**1. Introduction**

Functionally graded materials (FGMs) are a distinct and varied class of materials with a wide range of uses, from home to commercial. The introduction of these materials in the field of mechanical and materials engineering aims to provide a novel and resilient material that satisfies mechanical, microstructural, and tribological requirements. In order to provide solutions with this kind of materials, these types of materials are designed and developed. Materials with continuous material properties in all

directions and some modifications to their microstructure are unable to withstand all temperature variations and gradients within a short period of the material thickness.

Even if they are successful, researchers with their creativity and knowledge are working hard to produce these materials to a greater level, but the production and characterization processes have flaws and limitations. This is frequently accomplished by progressively shifting the volume fraction of two components with various thermomechanical properties in a certain direction, resulting in a compound with various volume ratios [1]. For spacecraft with one side exposed to extremely high temperatures and the other exposed to extremely low temperatures, FGMs are the best choice because they distribute material functions throughout the material body for best heat resistance and mechanical qualities. FGM is used in the development of most industrial sectors' products today, including those in the automotive, information technology, computer science, and other related fields [2].

### **1.1 Development and progression of FGM**

Most of the research investigations are progressed with the development of functionally graded aluminum composites by the aid of centrifugal casting analyzed the influence of mechanical and wear properties of pure aluminum, boron carbide, silicon carbide, alumina, and titanium boride. Radhika et al. [3] in her research experimentations with FGM stated that the outer peripheries of the FGM exhibit higher hardness except in AlB4C and the outer zone exhibits tensile strength at its maximum. Chandrappa et al. [4] have synthesized with the aid of conventional powder metallurgy method at 436o C sintering temperature and depicted that high volume fraction of SiC caused clustering of carbide phase at grain boundaries, which restricts interparticle contacts and further becomes a wall for densification in their study titled, "manufacturing and characterization of Al-SiC FGM developed through powder metallurgy." For preparation of Al/Si functionally graded materials using ultrasonic separation method, Zhang Zhong tao et al. [5, 6] have successfully synthesized the standardized Al-SiC FGM and also depicted that increasing the composition of SiC makes the FGM harder and at a limiting value, it becomes brittle and crack formation is observed, with the highest compressive strength obtained at 7.5% of SiC insertion.

A research article designated as synthesis of hydroxyapatite in combination with titanium alloy to prepare FGM composites by powder methodology ultimately used as implant materials depicted that microhardness is increased by 28% when compared with steel alloys. Amir Arifin et al. [7] successfully processed HA/Ti FGMs and depicted that increasing the titanium percentage increases the hardness and compaction capability of the synthesized FGM. He has also illustrated the elements' flawless cohesion and excellent microstructural characteristics. Madhusudan et al. [8] successfully formulated a procedure to determine the optimal thickness of the mold material in the production of FGM in centrifugal casting, as well as inferred various parameters affecting FGM production, starting with preheating, molten metal heating, and solidification rate.


6. Conclusion

The Bohemian Massif hosts a significant quantity of uranium deposits bound by brittle shear zones developed in high-grade metamorphic rocks (Rožná, Okrouhlá Radouň, Zadní Chodov and Dyleň) and/or granites of the Klenov and Bor plutons (Okrouhlá Radouň, Vítkov II and Lhota). The shear zone-hosted uranium deposits consist of peneconcordant lenses or highly disseminated uranium mineralisation evolved in brecciaed shear zones. The host rocks of these deposits are strongly altered, exhibiting extensive albitisation, chloritisation, hematitisation, and desilification in pre-ore stages. By hydrothermal alteration, aceites are products of lowtemperature alkaline metasomatism associated with a significant input of Na2O and the loss of SiO2. Complex coffinite-uraninite or coffinite-uraninite-brannerite assemblages form the shear zone mineralisation with predominance coffinite about uraninite. Mineralisation evolved in shear zone-hosted uranium deposits of the Bohemian Massif displays enrichment of HREE, Y and Zr in examined uranium minerals, especially in coffinite. For analysed coffinites and brannerites, enrichment of Y (up to 3.4 wt.% Y2O3) and Zr (up to 13.8 wt.% ZrO2) is significant.


**3. Results**

There are some general observations of the behavior of the different sample solutions that deserve to be noted here. Due to the cohesion degree of the core sample not all treatment solutions were capable to completely disintegrate the sample's mass. The most effective reagent to turn the sample solution into homogeneous mud slurry was H2O2 regardless of its concentration or admixture. The sample aliquots that were treated with water or Na6O18P6 solution did not completely disintegrate and small chunks of sediment were left still standing in the beaker that required some extra mechanical effort to dissolve better. Finally, beaker 4 which contained simultaneously both H2O2 and Na6O18P6 exhibited strong foaming during treatment time.


**5. Role of meals in the generation of symptoms in functional dyspepsia**

Epidemiologic studies, both in the USA and Europe, have shown that 50 to 80% of subjects with functional dyspepsia indicate that their symptoms are meal-related [5]. Meal ingestion is associated with diverse changes in the environment of the gastrointestinal lumen, the gastro‐ intestinal function and potential physiopathological mechanisms. The two most cited causes of pathology are delayed gastric emptying and visceral hypersensitivity. After ingestion of a meal, patients with functional dyspepsia experience a marked rise in the intensity of their symptoms (epigastric burning, epigastric pain, fullness, bloating, nausea and belching) that persists for 4 hours [14]. Postprandial fullness is the most severe symptom that a meal aggravates.

How Food Triggers Gastrointestinal Symptoms?

of the balloon during barostat studies).

abnormal motility responses may ensue.

hypersensitivity, and with abdominal pain [23,24].

dietary manipulation.

The enteric nervous system is a major controller of multiple gut functions, such as secretion, motility, blood flow and mucosal growth. In a normal situation, low intensity stimuli from the lumen have few discernible effects on motility (as occurs in association with minimal inflation

Diet in the Etiology and Management of Functional Dyspepsia

http://dx.doi.org/10.5772/57138

99

In most patients with functional gastrointestinal disorders, there is a change in relationship between stimulus intensity and perception (the hallmark of visceral hypersensitivity) and efferent motility response. These people experience pain in response to low intensity stimuli;

Luminal events may be initiated via two main stimuli: mechanical (associated with distention of the gut wall) and chemical stimuli. Chemical stimuli trigger specific enteroendocrine cells of the gut, releasing serotonin, which stimulates primary afferents of the enteric nervous system [21]. There is also evidence that some enteric neurons might directly respond to mechanical stimuli: the transient receptor potential (TRP) cation channels seem to be involved in most levels of control of gastrointestinal function, including visceral hypersensitivity [22]. The TRPV1 (vanilloid) channels appear to be central to the initiation and persistence of visceral hypersensitivity in an animal model. Increased expression of TRPV1 channels in neurons of the gut has been observed in patients with IBS; such expression correlates with visceral

Food stimulates the gut through the release of enteric hormones and particularly via the enteric nervous system. A primary trigger is luminal distention, which results from the physical act of ingesting food and from secondary events such as gas production (especially bacterial fermentation). Food also contains potent chemicals. If the food constituents that stimulate the enteric nervous system were to be identified, then these would become obvious targets for

On the basis of these concepts (luminal distention, visceral hypersensitivity and chemical stimuli of the enteric nervous system), three specific areas of proven or suspected food-induced gut symptoms in patients with functional GI symptoms are important: a. FODMAPs (fer‐ mentable oligo-, di- and monosaccharides and polyols) that include luminal distention; b. food chemicals (salicylates, amines) that potentially stimulates the enteric nervous system (ENS),

Carbohydrates occur across a range of foods regularly consumed including grains such as wheat and rye, vegetables, fruit and legumes. Short-chain carbohydrates with chain lengths up to 10 sugars vary in their digestibility and subsequent absorption. Those that are poorly absorbed exert osmotic effects in the intestinal lumen increasing its water volume. They are also rapidly fermented by bacteria yielding consequent gas production. These two effects may underlie many of the gastrointestinal symptoms that follows their ingestion. Only monosac‐ charides (glucose, galactose) can be actively absorbed across the small intestinal epithelium.

and c. gluten that may trigger symptoms by as yet unknown mechanisms.

**a.** *Targeting luminal distention: The FODMAP approach*

Disturbances in upper gastrointestinal motor functions in FD have received considerable attention. Not surprisingly, current treatments such as prokinetics are primarily directed to these abnormalities. Therapies for visceral hypersensitivity remain difficult to establish. Factors such as eating patterns (meal size and frequency, nutrient composition, overall energy intake) and intolerances to specific foods or food groups have received little attention so far.

## **6. Dietary factors in functional dyspepsia**

#### **6.1. Eating patterns**

Patients with functional dyspepsia frequently report that they are able to tolerate only small quantities of food [15], suggesting that their eating patterns differ from healthy subjects [8]. As a result of eating smaller quantities of food with lower energy intake, over half of FD patients experience weight loss even with a tendency to snack [16]. Despite eating fewer meals and consuming less total energy and fat, patients with FD experience fullness that is directly related to the amount of fat ingested and overall energy intake, while inversely related to the amount of carbohydrates ingested. Management of FD patients therefore might be improved by consuming smaller meals with reduced fat content [17,18].

#### **6.2. Food intolerances**

Patients with functional dyspepsia appear to exhibit more food intolerances than healthy persons, although studies are limited.

The belief that food is causing or at least triggering gut symptoms has led to the application of investigations purporting to guide dietary design. Various tests for food "intolerances" are widely available, such as skin prick (allergy) tests and assays for food specific immunoglobu‐ lins, but their value is unknown. Furthermore, various diets including wheat-free, anticandida, carbohydrate-free, and other complex exclusions diets are touted in books and on the internet but evidence for any benefit is lacking.[19] The exception is the gluten-free diet, which will be discussed later in the chapter.

Alternative health practitioners and some nutritionists have advocated many such diets and intolerance-testing.

Therefore, gastroenterologists often are left with a defensive role when patients request dietary interventions. Although gastroenterologists may appreciate that food is an undoubted trigger, it is difficult to recognize the specific food item. Tests designed to this have a poor predictive value, while the resulting diets are often overly restrictive with the potential to render the patient nutritionally compromised [20].

#### How Food Triggers Gastrointestinal Symptoms?

meal, patients with functional dyspepsia experience a marked rise in the intensity of their symptoms (epigastric burning, epigastric pain, fullness, bloating, nausea and belching) that persists for 4 hours [14]. Postprandial fullness is the most severe symptom that a meal

Disturbances in upper gastrointestinal motor functions in FD have received considerable attention. Not surprisingly, current treatments such as prokinetics are primarily directed to these abnormalities. Therapies for visceral hypersensitivity remain difficult to establish. Factors such as eating patterns (meal size and frequency, nutrient composition, overall energy intake) and intolerances to specific foods or food groups have received little attention so far.

Patients with functional dyspepsia frequently report that they are able to tolerate only small quantities of food [15], suggesting that their eating patterns differ from healthy subjects [8]. As a result of eating smaller quantities of food with lower energy intake, over half of FD patients experience weight loss even with a tendency to snack [16]. Despite eating fewer meals and consuming less total energy and fat, patients with FD experience fullness that is directly related to the amount of fat ingested and overall energy intake, while inversely related to the amount of carbohydrates ingested. Management of FD patients therefore might be improved

Patients with functional dyspepsia appear to exhibit more food intolerances than healthy

The belief that food is causing or at least triggering gut symptoms has led to the application of investigations purporting to guide dietary design. Various tests for food "intolerances" are widely available, such as skin prick (allergy) tests and assays for food specific immunoglobu‐ lins, but their value is unknown. Furthermore, various diets including wheat-free, anticandida, carbohydrate-free, and other complex exclusions diets are touted in books and on the internet but evidence for any benefit is lacking.[19] The exception is the gluten-free diet, which

Alternative health practitioners and some nutritionists have advocated many such diets and

Therefore, gastroenterologists often are left with a defensive role when patients request dietary interventions. Although gastroenterologists may appreciate that food is an undoubted trigger, it is difficult to recognize the specific food item. Tests designed to this have a poor predictive value, while the resulting diets are often overly restrictive with the potential to render the

**6. Dietary factors in functional dyspepsia**

98 Dyspepsia - Advances in Understanding and Management

by consuming smaller meals with reduced fat content [17,18].

aggravates.

**6.1. Eating patterns**

**6.2. Food intolerances**

intolerance-testing.

persons, although studies are limited.

will be discussed later in the chapter.

patient nutritionally compromised [20].

The enteric nervous system is a major controller of multiple gut functions, such as secretion, motility, blood flow and mucosal growth. In a normal situation, low intensity stimuli from the lumen have few discernible effects on motility (as occurs in association with minimal inflation of the balloon during barostat studies).

In most patients with functional gastrointestinal disorders, there is a change in relationship between stimulus intensity and perception (the hallmark of visceral hypersensitivity) and efferent motility response. These people experience pain in response to low intensity stimuli; abnormal motility responses may ensue.

Luminal events may be initiated via two main stimuli: mechanical (associated with distention of the gut wall) and chemical stimuli. Chemical stimuli trigger specific enteroendocrine cells of the gut, releasing serotonin, which stimulates primary afferents of the enteric nervous system [21]. There is also evidence that some enteric neurons might directly respond to mechanical stimuli: the transient receptor potential (TRP) cation channels seem to be involved in most levels of control of gastrointestinal function, including visceral hypersensitivity [22]. The TRPV1 (vanilloid) channels appear to be central to the initiation and persistence of visceral hypersensitivity in an animal model. Increased expression of TRPV1 channels in neurons of the gut has been observed in patients with IBS; such expression correlates with visceral hypersensitivity, and with abdominal pain [23,24].

Food stimulates the gut through the release of enteric hormones and particularly via the enteric nervous system. A primary trigger is luminal distention, which results from the physical act of ingesting food and from secondary events such as gas production (especially bacterial fermentation). Food also contains potent chemicals. If the food constituents that stimulate the enteric nervous system were to be identified, then these would become obvious targets for dietary manipulation.

On the basis of these concepts (luminal distention, visceral hypersensitivity and chemical stimuli of the enteric nervous system), three specific areas of proven or suspected food-induced gut symptoms in patients with functional GI symptoms are important: a. FODMAPs (fer‐ mentable oligo-, di- and monosaccharides and polyols) that include luminal distention; b. food chemicals (salicylates, amines) that potentially stimulates the enteric nervous system (ENS), and c. gluten that may trigger symptoms by as yet unknown mechanisms.

#### **a.** *Targeting luminal distention: The FODMAP approach*

Carbohydrates occur across a range of foods regularly consumed including grains such as wheat and rye, vegetables, fruit and legumes. Short-chain carbohydrates with chain lengths up to 10 sugars vary in their digestibility and subsequent absorption. Those that are poorly absorbed exert osmotic effects in the intestinal lumen increasing its water volume. They are also rapidly fermented by bacteria yielding consequent gas production. These two effects may underlie many of the gastrointestinal symptoms that follows their ingestion. Only monosac‐ charides (glucose, galactose) can be actively absorbed across the small intestinal epithelium. Di- and oligosaccharides must be hydrolyzed to their constituent hexoses for absorption to occur. All these molecules are plentiful in the diet and have been termed FODMAPs1

In general, the stronger the flavor of the food, the higher the chemical content will be. In clinical practice, food chemicals have received some attention in the pathogenesis and management

Food chemicals are major afferent stimuli to the enteric nervous system. In the presence of visceral hypersensitivity, normal physiological stimulation by such chemicals might result in exaggerated effector responses (luminal distention). [32] Plant chemicals are able to activate TRP channels. Chronic exposure to certain chemicals will lead to increased expression of TRP channels and this contributes to a higher sensitivity of the enteric nervous system, and thus to the development of functional gut symptoms. Withdrawing the offending chemicals from the diet may reverse the TRP channel overexpression with subsequent resolution of the gut

The only food chemicals that have been systematically studied with respect to gut symptoms are salicylates and related molecules such as non-steroid anti-inflammatory drugs. 2 to 4 % of patients with irritable bowel syndrome (IBS) or food allergies are salicylate-drug intolerant [29]. Examples of food sources containing high amounts of potentially bioactive chemicals are

**Salicylates Amines Glutamates**

Eggplant, olives

Brie , camembert, parmesan , tasty cheeses

tempeh

Surimi, soy sauce , miso,

Redcurrant Dried prunes, raisins,

Diet in the Etiology and Management of Functional Dyspepsia

http://dx.doi.org/10.5772/57138

101

grapes, plum, sultanas

Brie , camembert , parmesan

protein

Canned baked beans in sauce , textured vegetable

of urticaria, headaches, asthma and anaphylactic reactions.

Avocado, berries , cherry, citrus , date, grape , kiwifruit, pineapple, plum ,

Mushrooms, sauerkraut, spinach, tomato, chicory, eggplant, onion, chili, ginger, herbs

Breakfast cereals , mueslis, dried fruit, honey, coconut,

strawberry

potato chips

nut pasta

seed pasta

sauce

Seeds Mustard seeds, sesame

Almond, hazelnut, marzipan , peanut butter ,

Milk with chocolate, strawberry or banana flavor , yoghurt

Bean mixes , broad beans , canned baked beans in

symptoms.

Fruits

Vegetables

Grains , cereals

Milk , milk products

Legumes

Nuts

summarized in Table 2.

FODMAPs are therefore poorly absorbed, highly osmotic and rapidly fermented by gastroin‐ testinal bacteria, leading to increased water and gas. The result is intestinal distention that also effects changes in motility, leading to symptoms of bloating and discomfort [26]. FOPMAPs induce functional symptoms in patients with IBS who have fructose malabsorption; reduction of dietary FODMAPs produces a durable symptomatic response [27, 28].

Some common food sources of FODMAPs are summarized in table 1:

#### **Table 1.**

#### **b.** *Targeting food chemicals*

Plants produce a wide variety of chemicals, some of which have survival function (the bad taste for protection, odors for reproduction), along with antibacterial or preservative proper‐ ties.

Potentially bioactive chemicals include salicylates (that have a protective role), amines and glutamates (that are products of protein breakdown), and common food additives such as benzoates, sulfites and, nitrates (as preservatives).

1 FODMAP is an acronym for different carbohydrates: F: fermentable; O: oligosaccharides (fructans , galacto-oligosac‐ charides); D: disaccharides (lactose); M: monosaccharides (fructose); A: and P: polyols (sorbitol , mannitol , xylitol , maltitol) [25].

In general, the stronger the flavor of the food, the higher the chemical content will be. In clinical practice, food chemicals have received some attention in the pathogenesis and management of urticaria, headaches, asthma and anaphylactic reactions.

Di- and oligosaccharides must be hydrolyzed to their constituent hexoses for absorption to

FODMAPs are therefore poorly absorbed, highly osmotic and rapidly fermented by gastroin‐ testinal bacteria, leading to increased water and gas. The result is intestinal distention that also effects changes in motility, leading to symptoms of bloating and discomfort [26]. FOPMAPs induce functional symptoms in patients with IBS who have fructose malabsorption; reduction

**Lactose Fructose Polyols**

Apple, apricot, pear, avocado, cherry, blackberries, plum, prune, nectarine

Cauliflower, mushroom, snow peas

xylitol, isomalt

Apple, cherry, mango, pear, Watermelon

Asparagus, artichokes, sugar snap peas

fructose corn syrup

occur. All these molecules are plentiful in the diet and have been termed FODMAPs1

custard, soft cheeses

Food additives Inulin Sorbitol, mannitol, maltitol,

Plants produce a wide variety of chemicals, some of which have survival function (the bad taste for protection, odors for reproduction), along with antibacterial or preservative proper‐

Potentially bioactive chemicals include salicylates (that have a protective role), amines and glutamates (that are products of protein breakdown), and common food additives such as

1 FODMAP is an acronym for different carbohydrates: F: fermentable; O: oligosaccharides (fructans , galacto-oligosac‐ charides); D: disaccharides (lactose); M: monosaccharides (fructose); A: and P: polyols (sorbitol , mannitol , xylitol ,

of dietary FODMAPs produces a durable symptomatic response [27, 28].

Some common food sources of FODMAPs are summarized in table 1:

**Oligosaccharides, fructans**

100 Dyspepsia - Advances in Understanding and Management

watermelon

Artichokes, beetroot, Brussels sprouts, chicory, garlic, onion, peas

Milk Milk, yoghurt, ice-cream,

benzoates, sulfites and, nitrates (as preservatives).

Other Chicory drinks Honey, high

Fruit Peach, persimmon,

Grains , cereals Wheat , rye, barley Nuts pistachios

Legumes Lentils, chickpeas

**b.** *Targeting food chemicals*

Vegetables

**Table 1.**

ties.

maltitol) [25].

Food chemicals are major afferent stimuli to the enteric nervous system. In the presence of visceral hypersensitivity, normal physiological stimulation by such chemicals might result in exaggerated effector responses (luminal distention). [32] Plant chemicals are able to activate TRP channels. Chronic exposure to certain chemicals will lead to increased expression of TRP channels and this contributes to a higher sensitivity of the enteric nervous system, and thus to the development of functional gut symptoms. Withdrawing the offending chemicals from the diet may reverse the TRP channel overexpression with subsequent resolution of the gut symptoms.

The only food chemicals that have been systematically studied with respect to gut symptoms are salicylates and related molecules such as non-steroid anti-inflammatory drugs. 2 to 4 % of patients with irritable bowel syndrome (IBS) or food allergies are salicylate-drug intolerant [29]. Examples of food sources containing high amounts of potentially bioactive chemicals are summarized in Table 2.

biopsy-proven celiac disease in individuals with dyspepsia may be as low as 1%, a value similar to that amongst individuals in the general population, or markedly higher at 6% to 9% [37]. Routine screening for celiac disease therefore seems useful through serological testing and with distal duodenal biopsy during upper gastrointestinal endoscopy done to investigate

Diet in the Etiology and Management of Functional Dyspepsia

http://dx.doi.org/10.5772/57138

103

B. *Gluten (wheat) sensitivity*. Gluten may also induce other pathological conditions, such as a wheat allergy. Wheat allergy is an immunoglobulin IgE–mediated disease and thus com‐ pletely unrelated to celiac disease. [33] Recent attention however has been given to another entity: gluten or wheat sensitivity (also termed non-celiac gluten sensitivity). This disorder misses one or more of the key criteria: enteropathy and the presence of specific autoantibod‐ ies that define celiac disease (CD). The current working definition of non-celiac gluten sensi‐ tivity is the occurrence of irritable bowel syndrome (IBS)-like symptoms after ingesting gluten, and improvement after gluten withdrawal from the diet. Celiac disease must be ex‐ cluded by negative celiac serology or a normal intestinal architecture, while wheat allergy should be negated by a negative IgE-mediated allergy test to wheat. Non-celiac gluten sensi‐ tivity (NCGS) thus encompasses a collection of medical conditions in which gluten leads to an adverse food reaction, clinically similar to some features of celiac disease, but celiac test‐ ing is negative or inconclusive [38, 39]. Such non-celiac IBS patients, in whom celiac disease

The key question is the mechanism by which gluten induces symptoms. Gluten may mediate cholinergic activation, leading to increased smooth muscle contractility and indirectly have effects on luminal water content. Another explanation might be the release of neutrally active peptides from the gluten digestion that might potentially gain access to enteric nerve endings. Gluten ingestion can precipitate duodenal tissue eosinophilia in those with wheat sensitivity [39]. Although there is no well-established mechanism for NCGS, the gluten-free diet has

Because of the many patients with functional dyspepsia and its serious impairment to their quality of life, this entity represents an important clinical challenge. Pharmacologic therapies are limited, leaving patients and physicians to often use dietary strategies in managing FD.

Unfortunately most of the available information concerning the role of diet and food intake in FD patients is inconclusive. Several studies fortunately have shown clear differences between FD patients and healthy persons in the ability to tolerate certain types of foods including

FD patients often maintain regular consumption of several foods despite these being impli‐ cated with the dyspepsia. Why these patients do not avoid the majority of food components, which they link to dyspepsia, remains unclear. Possible reasons might be ignorance of this association, a lack of alternatives to replace food items, or cultural habits such as the use of

is excluded, will improve on a gluten-free diet [30].

gained substantial popularity with the general public.

fermentable carbohydrates (FODMAPs).

**7. Dietary management strategies in functional dyspepsia**

dyspepsia.

**Table 2.** Examples of food sources with very high amounts of salicylates, amines and glutamates (reference: http:// www.allergy.net.eu)

#### **c.** *Targeting gluten: A suspected molecule without a known mechanism*

A. *Celiac disease* in recent years has undergone a profound revision. Celiac disease (CD) is now considered to be a systemic immune-mediated disorder elicited by gluten. The common denominator for all patients with CD is the presence of a combination of gluten-dependent clinical manifestations, specific autoantibodies (anti–tissue transglutaminase, anti-endomysial antibodies plus serum IgA) and different degrees of enteropathy, ranging from lymphocytic infiltration of the epithelium to complete villous atrophy. [33, 34] Nevertheless, CD remains underdiagnosed in all age groups. The advent of serological testing has improved the detection of celiac disease but typical endoscopic findings for villous atrophy such as scalloping of folds, a mosaic pattern, or decreased folds are often not evident in less severe cases. Magnification tools like confocal endomicroscopy or "water immersion" techniques help characterize the abnormal duodenal mucosa and target biopsying. In many patients, particular adults, the disease features atypical symptoms or is completely silent, the so-called "celiac iceberg". Upper abdominal symptoms, such as abdominal pain and dyspepsia, are a common primary complaint in CD [36]. 30 to 40 % of celiac patients have dyspeptic symptoms. From a different perspective, diagnostic testing for celiac disease in individuals with dyspepsia has some advocates, because of a trend to a greater prevalence [35]. Nevertheless, the prevalence of biopsy-proven celiac disease in individuals with dyspepsia may be as low as 1%, a value similar to that amongst individuals in the general population, or markedly higher at 6% to 9% [37]. Routine screening for celiac disease therefore seems useful through serological testing and with distal duodenal biopsy during upper gastrointestinal endoscopy done to investigate dyspepsia.

**Salicylates Amines Glutamates**

Beef : billong, jerky Chicken : pressed , seasoned , gravy

Almond oil , extra virgin olive oil , sesame oil

Beer , champagne , cider , tea , herbal tea , wine

Jam , fruit flavored sweets , yeast extract , fermented products , chicken salt , sauces ( tomato , soy , fish

and oyster)

Ham , bacon , anchovies, prawns tuna , fish : pickled ,

Almond oil , extra virgin olive oil , sesame oil

Beer , champagne , cider , tea , herbal tea , wine Chocolate drinks , cocoa

Jam , marmalade , yeast extract , vinegar , chocolate , sauces ,

salted, smoked

powder

**Table 2.** Examples of food sources with very high amounts of salicylates, amines and glutamates (reference: http://

A. *Celiac disease* in recent years has undergone a profound revision. Celiac disease (CD) is now considered to be a systemic immune-mediated disorder elicited by gluten. The common denominator for all patients with CD is the presence of a combination of gluten-dependent clinical manifestations, specific autoantibodies (anti–tissue transglutaminase, anti-endomysial antibodies plus serum IgA) and different degrees of enteropathy, ranging from lymphocytic infiltration of the epithelium to complete villous atrophy. [33, 34] Nevertheless, CD remains underdiagnosed in all age groups. The advent of serological testing has improved the detection of celiac disease but typical endoscopic findings for villous atrophy such as scalloping of folds, a mosaic pattern, or decreased folds are often not evident in less severe cases. Magnification tools like confocal endomicroscopy or "water immersion" techniques help characterize the abnormal duodenal mucosa and target biopsying. In many patients, particular adults, the disease features atypical symptoms or is completely silent, the so-called "celiac iceberg". Upper abdominal symptoms, such as abdominal pain and dyspepsia, are a common primary complaint in CD [36]. 30 to 40 % of celiac patients have dyspeptic symptoms. From a different perspective, diagnostic testing for celiac disease in individuals with dyspepsia has some advocates, because of a trend to a greater prevalence [35]. Nevertheless, the prevalence of

Beef : smoked , corned ,

Almond oil , extra virgin olive oil , sesame , avocado

Flavored mineral waters, spirits (except gin, tonic, whisky, vodka) , wine, fruit juices, ginger beer, beer , champagne , cider , herbal

Jam , marmalade , fruit flavored syrup , yeast extract , vinegar (cider , red

**c.** *Targeting gluten: A suspected molecule without a known mechanism*

and white wine) Honey , peppermints, tomato sauce , soy sauce

Chicken : nuggets , smoked Meat pastes , fish pastes ,

dried

102 Dyspepsia - Advances in Understanding and Management

salami

oil

tea , tea

Meat, fish , chicken

Fats and oils

Beverages

Other

www.allergy.net.eu)

B. *Gluten (wheat) sensitivity*. Gluten may also induce other pathological conditions, such as a wheat allergy. Wheat allergy is an immunoglobulin IgE–mediated disease and thus com‐ pletely unrelated to celiac disease. [33] Recent attention however has been given to another entity: gluten or wheat sensitivity (also termed non-celiac gluten sensitivity). This disorder misses one or more of the key criteria: enteropathy and the presence of specific autoantibod‐ ies that define celiac disease (CD). The current working definition of non-celiac gluten sensi‐ tivity is the occurrence of irritable bowel syndrome (IBS)-like symptoms after ingesting gluten, and improvement after gluten withdrawal from the diet. Celiac disease must be ex‐ cluded by negative celiac serology or a normal intestinal architecture, while wheat allergy should be negated by a negative IgE-mediated allergy test to wheat. Non-celiac gluten sensi‐ tivity (NCGS) thus encompasses a collection of medical conditions in which gluten leads to an adverse food reaction, clinically similar to some features of celiac disease, but celiac test‐ ing is negative or inconclusive [38, 39]. Such non-celiac IBS patients, in whom celiac disease is excluded, will improve on a gluten-free diet [30].

The key question is the mechanism by which gluten induces symptoms. Gluten may mediate cholinergic activation, leading to increased smooth muscle contractility and indirectly have effects on luminal water content. Another explanation might be the release of neutrally active peptides from the gluten digestion that might potentially gain access to enteric nerve endings. Gluten ingestion can precipitate duodenal tissue eosinophilia in those with wheat sensitivity [39]. Although there is no well-established mechanism for NCGS, the gluten-free diet has gained substantial popularity with the general public.


**4.1 Cases**

It is believed that minimally invasive therapy can reduce morbidity and mortality in sickle cell disease patients. The safety of laparoscopic cholecystectomy in such patients has already been recognized. Rachid et al [10] reported the results of their experience on laparoscopic cholecystectomy in sickle cell disease patients in Niger, which is included in the sickle cell belt. Their study covered 45 months and included 47 patients operated by the same surgeon. The average age was 22.4 years (range: 11 to 46 years) and eleven (23.4%) of them were aged less than 15 years. The types of sickle cell disease found were 37 SS, 2 SC, 1 S betathalassemia and 7 AS. The indications for their surgeries were biliary colic in 29 cases (61.7%) and acute cholecystitis in 18 cases (38.3%). Their mean operative time was 64 minutes. Reports from the authors states that there were conversions to open cholecystectomy in 2 cases (4.2 %) for non recognition of Calot's triangle structures. They reported four cases of postoperative complications of vaso-occlusive crisis and one case of acute chest syndrome. Their mean postoperative hospital stay was 3.5days (range: 1 to 9 days). There was no mortality encountered. The authors concluded that laparoscopic cholecystectomy is a safe procedure in sickle cell patients and that it should be a multidisciplinary approach and involve the haematologist, anaesthesiologist and a surgeon.

Haberkem et al [12] studied a group of 364 patients who underwent cholecystectomy. There were ninety-eight percent of their patients who had symptomatic cholelithiasis. Their total perioperative morbidity was 39% and they reported that while total morbidity is not affected by preoperative transfusion, the incidence of specific sickle cell events is higher in those patients who were not transfused preoperatively than in those who were. Laparoscopic cholecystectomy was accompanied by shorter hospitalization time (6.4 days) than the open cholecystectomy (9.8 days) and noted that perioperative outcomes were the same with both techniques. The authors concluded that conservative preoperative transfusion and use of the laparoscopic technique are necessary for patients with sickle cell disease who will be undergoing cholecystectomy to prevent further complications.


3.4.2. DPPH Radical Scavenging Assay

The DPPH radical scavenging assay is among the most frequently used antioxidant assays and offers a first approach for evaluating the antioxidant capacity of a complex mixture [44]. In the current research, the DPPH activity of the tested goji berries ranged from na (not active, B1D sample) to the highest value of 40.32 ± 4.01 mg TE/g extract (for the Italian W5D sample). Zhang et al. [38] obtained values ranging between 35.88 ± 2.2 to 85.46 ± 1.9 μM TE/g fresh weight for the DPPH antioxidant capacity assay from eight Chinese goji genotypes, while Abdennacer et al. [43] reported a value of 0.05 mg TE/mg dry weight for the methanolic extracts of fruits of Tunisian *Lycium intricatum*.


*3.1. Velocity Models with Anomalies*

We have generated various types of velocity models. The basic type is a velocity model with one anomaly and no fault. Through the controlled variable method, the other velocity fields are multiple (two) anomalies with no fault and one anomaly with fault. According to the natural laws of geophysics, the velocity in the upper level (near the surface) is small, and the velocity increases as the depth increases. The location and size of the anomalies are randomly generated, and the default shape of the anomaly is an ellipse. The length of the semi-axis of the ellipse is [20, 100]. Figure 7 shows the different types of velocity models.

**Figure 7.** Examples of velocity models.


**5. Smart irrigation and climate-risks**

Deploying smart irrigation system may lower the overall irrigation water volume necessary to cultivate field crops in two ways. First, producers may eliminate noncropped or marginal regions from water application, and second, producers can limit application rates in low-lying areas or soils with high water-holding capacity. Field

*Smart Irrigation for Climate Change Adaptation and Improved Food Security DOI: http://dx.doi.org/10.5772/intechopen.106628*

**Figure 7.** *Thinkspeak clould platform, Source [55].*

installation of smart irrigation systems has demonstrated typical savings in irrigation water consumption of 8–20% [56] compared to uniform irrigation application. Using an intelligent irrigation system may assist minimize irrigation withdrawals while still maintaining a well-watered crop. This allows effective water usage and may lessen the likelihood of transient well failures during droughts. Having the machinery and availability to water for irrigation makes irrigated croplands less exposed to climaterelated threats than their dryland equivalents. Smart irrigation decreases this danger by enhancing irrigation water-use efficiency and minimizing freshwater withdrawals to allow for more predictable water supply.


Meet the editors

Prof. Margarita Stoytcheva graduated from the University of Chemical Technologies and Metallurgy at Sofia, Bulgaria, as a chemical engineer and master of electrochemical technologies. She has PhD and DS. degrees in Chemistry and Technical Sciences. She has been a researcher and teacher in several universities in Bulgaria, Algeria, and France. From 2006 to the present, she has participated in activities of scientific research, technological

development, and teaching in Mexico at the Autonomous University of Baja California at Mexicali as a full-time researcher. Since 2008 she has been a member of the National System of Research of Mexico, and since 2011 she has been a regular member of the Mexican Academy of Sciences. Her interests and area of research are analytical chemistry and biotechnology.

Dr. Roumen Zlatev is a full-time researcher at the Engineering Institute of the Autonomous University of Baja California (UABC) at Mexicali, Mexico. He obtained his bachelor's and master's degrees from the University of Chemical Technology and Metallurgy of Sofia, Bulgaria, and his PhD degree from the National Polytechnic University of Grenoble, France. He was a full-time researcher at the Bulgarian Academy of Sciences and a

part-time professor at Sofia University. In 2005 he accepted the position of fulltime senior researcher at UABC. Dr. Zlatev is a member of the Mexican National System of Researchers and a regular member of the Mexican Academy of Sciences. He participates in research projects in France, Germany, and Mexico. Dr. Zlatev is the author of more than 170 publications, book chapters, and reports in scientific congresses and holds 14 patents in the field of electrochemical and spectroscopic methods of analysis, corrosion and materials, and electrochemical and analytical instrumentation.

Contents

**Section 1**

and Molecular Diagnostic

Healing Based on Synthetic Polymers

*and Vaibhav Tripathi*

*and Alla Sinica*

**Section 2**

*by Jiahao Yan and Yuchao Li*

**Preface XI**

Nanomaterials in Medicine, Agriculture and Biosensorics **1**

**Chapter 1 3**

**Chapter 2 19**

**Chapter 3 33**

**Chapter 4 63**

**Chapter 5 77**

Nanofluidics **91**

**Chapter 6 93**

**Chapter 7 113**

Nanoparticle Synthesis, Applications, and Toxicity *by Hamid-Reza Rahimi and Mohsen Doostmohammadi*

Role of Nanobiotechnology in Drug Discovery, Development

*by Deepak Kumar Dash, Rajni Kant Panik, Anil Kumar Sahu*

Nanofibrous Scaffolds for Skin Tissue Engineering and Wound

Electro-Optical Manipulation Based on Dielectric Nanoparticles

Nanofluids and Computational Applications in Medicine and Biology

Convection Currents in Nanofluids under Small Temperature Gradient

*by Lucie Bacakova, Marketa Zikmundova, Julia Pajorova, Antonin Broz, Elena Filova, Andreu Blanquer, Roman Matejka, Jana Stepanovska, Petr Mikes, Vera Jencova, Eva Kuzelova Kostakova*

Applications of Nanotechnology in Agriculture *by Alaa Y. Ghidan and Tawfiq M. Al Antary*

*by Laith Jaafer Habeeb and Hasan Shakir Majdi*

*by Jyoti Sharma and Urvashi Gupta*


*2.5. Analysis*

Analysis of the transcripts was completed using NVivo 12 [21]. Narrative analysis was used where key themes under each of the broad research objectives were derived. All transcripts were coded against a priori key themes based on the research questions, including the acceptability of each of the WHO drowning reduction programs, and considerations for the implementation and feasibility of using government programs to deliver the programs. Subsequent sub-themes were developed under each of these based on commonalities and diversified perspectives from participants. We also triangulated di fferent sources of data by coding for the type of stakeholder and type of qualitative method (IDI, FGD, observation) to assess congruent and di fferent perspectives across genders and participant type as well as to compare individual and community-level viewpoints [22]. The two independent reviewers (M.G. and P.K.) discussed their results and discrepancies before finalising the key findings.

Stakeholders were identified and then allocated to level of power and interest as based on Mendelow's Matrix [23]. The level of power describes the stakeholder's influence over program success, and the level of interest reflects the impacts of the program on the stakeholder. The framework was used to identify the correct engagement strategies for each of the stakeholders based on their framework allocation.


*3.1. Unmodified Electrode*

Detergent solubilised membrane proteins can be absorbed directly on carbon, metal or semi-conductor electrodes in an approach known as protein film electrochemistry (Figure 2a) [33]. A frequently used electrode material is pyrolytic graphite "edge" (PGE) which has a rough, negatively charged surface, which can be tailored with polycations such as polymixin B or poly-l-lysine if required. Respiratory nitrate reductase (NarGHI) isolated from *Paracoccus pantotrophus* in *n*-dodecyl β-D-maltoside (DDM) buffer was adsorbed onto PGE electrodes and showed direct electron transfer (DET) with the electrode [34]. The catalytic activity of NarGHI from *E. coli* was studied over a wide pH range (5 < pH < 9), nitrate concentrations and in the presence of inhibitor [35]. Similarly, purple bacteria RC-LH I was solubilised in 0.1% lauryldimethylamine N-oxide (LDAO) buffer and immobilised directly on a bare Au electrode [36]. RC-LH I did not exhibit DET, but showed photocurrents (~64 nA/cm2 ) when ubiquinone-0 and cytochrome *c* were present in solution, indicating that electron transfer needs to be mediated by small redox compounds in this system (mediated electron transfer, MET). Like water-soluble proteins, membrane proteins on bare electrodes often lack a specific orientation and this can impede efficient electron transfer between electrode and proteins. Making use of the amphiphilic nature of membrane proteins, a densely packed protein monolayer with defined orientation can be formed on electrode surfaces by Langmuir−Blodgett deposition and this was shown to increase the electron transfer efficiency [37–41]. An example of this strategy can be found in Kamran et al. where detergent solubilised-RC-LH I was first pre-assembled in a monolayer at a water-air interface and then transferred onto a gold-coated electrode, reaching photocurrent values of ~45 µA/cm2 [37].


Rotaviral Diseases and Their Implications

*Kirti Nirmal and Seema Gangar*

#### **Abstract**

Rotaviruses (Latin rota, "wheel"), the name derived from the wheel-like appearance of the virions when viewed by negative-contrast electron microscopy Rotavirus, are one of the foremost causes of rigorous peadiatric diarrhea globally. According to WHO, it is the primary cause of severe diarrhea among young children, leading to 4.5 million hospitalizations and more than 700,000 deaths of children aged 5 and under annually. The viruses are present in the stool of an infected person and can remain viable for a long time on contaminated surfaces, including people's hands. They are transmitted by fecal-oral route. Fecal contamination of food and water are common reservoirs and fingers, flies and fomites play vehicular role in transmission of rotaviruses. Both symptomatic and asymptomatic infections can lead to viral transmission due to shedding of viruses, often observed in close contacts, day care centers or via infected food handlers or healthcare workers. The disease manifested the symptoms of rotavirus infection, which may last up to 8 days and comprises fever, nausea, vomiting, abdominal cramps, and frequent, watery diarrhea. Two types of the rotavirus vaccine RotaTeq (RV5) and Rotarix (RV1) are available. Both vaccines are administrated orally, not as a shot. This chapter focuses on new information related to the clinical presentation and pathogenesis of rotavirus infection and its implications.

**Keywords:** rotavirus, disease, virus, systematic review

#### **1. Introduction**

Rotaviruses are recognized as a major cause of viral gastroenteritis among children since 1973 when Ruth F. Bishop and his colleagues observed the virus particles in the duodenal epithelial cells of gastroenteritis patients by electron microscopy [1]. As per WHO, Rotaviruses are responsible for approximately 453,000 deaths/year among children aged <5 years, globally, and over 2 million children are hospitalized each year with pronounced dehydration from rotavirus infection [2].

#### **2. Taxonomy**

The rotavirus (RV) genome is comprised of eleven segments of double-stranded RNA (dsRNA) and is contained within a non-enveloped, icosahedral particle.

During assembly, a highly-coordinated selective packaging mechanism ensures that progeny RV virions contain one of each genome segment. It has two subfamilies: Sedoreovirinae and Spinareovirinae [3].

#### **3. Morphology**

The name Rotaviruses (Latin *rota*, "wheel") is derived from the wheel-like appearance of the virions when viewed by negative-contrast electron microscopy (**Figure 1**). The mature virion has an approximate diameter of about 100 nm and possesses icosahedral symmetry. It is made up of three concentric protein layers and thus also known as a "triple-layered particle" or TLP. The mature virion lacks a lipid envelope (**Figure 2**) [4]. However, there is the acquisition of a transient lipid envelope during the budding of immature particles into the endoplasmic reticulum (ER). The triple-layered capsid encloses 11 discrete segments (seg 1–11) of linear dsRNA, which codes for six structural viral proteins, (VP1, VP2, VP3, VP4, VP6, and VP7) and six non-structural viral proteins (NSP1-NSP6). Each segment of dsRNA codes one protein except for segment 11, which codes two proteins (**Figure 3**) [5].

The outermost layer of the capsid is an icosahedral-shaped lattice made up of 780 copies of VP7 (38 kDa), a glycoprotein, and 120 copies of the spike protein VP4 (88 kDa) [6]. As per cryo-EM studies, VP4 has a large globular domain that is buried inside the inner layer, and it forms the spikes that emanate through the outer layer, which helps in cell attachment, penetration, hemagglutination, neutralization, and virulence of Rotaviruses [7]. The VP4 or the spike protein has a trypsin cleavage site along its length. The infectivity of virus particles gets enhanced by several folds on proteolytic cleavage of VP4 (88 kDa) into VP8∗ (28 kDa) and VP5∗ (60 kDa). It induces conformational changes to stabilize the spike protein. VP8∗ and VP5∗ remain

#### **Figure 1.**

*Transmission electron micrograph of rotavirus virions (viral particles). (https://www.cdc.gov/rotavirus/about/ photos.html) (taken permission from original resources).*

*Rotaviral Diseases and Their Implications DOI: http://dx.doi.org/10.5772/intechopen.109466*

#### **Figure 2.**

*3D graphical representation of rotavirus virions (viral particles). Rotavirus is known and named for the wheel-like appearance visible under an electron microscope (taken permission from original resources).*

**Figure 3.** *Structure of rotavirus.*

associated with the virion and facilitate virus entry into cells [8]. The intermediate layer of the virion is formed by 260 VP6 trimers in an icosahedral shape. The outer two layers consist of 132 aqueous channels of three types (types I–III), which play an important role in the transcription and translocation of mRNA. The virus particles that lack the outer layer are non-infectious and known as double-layered particles (DLPs), and particles that lack the outer two layers are known as single-layered particles (SLPs) [9]. The VP2 is the most abundant protein; it interacts with genomic RNA on the inside and the VP6 layer on its outer side. The rest of the core proteins are present in small quantities and provide the enzymatic functions required for producing the capped mRNA transcripts [10]. The components of outermost layer (VP7 and VP4) carry epitopes for eliciting neutralizing antibodies independently. Based on this, a dual classification system was established decades ago to define Rotavirus G (VP7 is a **G**lycoprotein) and P (VP4 is **P**rotease sensitive) genotypes. So far, 36 G genotypes and 51 P serotypes have been identified [11].

#### **4. Nucleic acid**

The genome of rotaviruses consists of 11 discrete segments of linear dsRNA of 18,555 bp size. The size of the segments ranges from 667 bp to 3302 bp. The genome is A + U rich (58–67%). **Table 1** describes the size, protein products encoded by segments of dsRNA, and functions of proteins of the Rotaviruses group [5, 11]. The minor proteins VP1 and VP3 form a heterodimer, which is anchored to the inner surface (N-terminal residues) of the VP2 layer and is known as the transcription enzyme complex. The VP2 layer in addition to proper positioning of the transcription enzyme complex helps in the regulation of endogenous transcription of the genome [5, 12]. The transcription of the genome is a dynamic process, the dsRNA segments move around the anchored transcription enzyme complex (**Figure 3**). The similar assembly of the structures has been observed in members of ortho-reoviruses; however, their capping enzyme is outside the innermost layer (**Table 1**).

#### **5. Replication**

Rotaviruses enter the body via the fecal-oral route and infect the epithelial cells of the villi in the small intestine. The virus multiplies in the cytoplasm of the epithelial cells [12]. The rotaviruses replicate well in continuous cell cultures derived from monkey kidneys. The replication cycle is approximately completed in 12–15 h at 37°C. The replication cycle can be divided into the following steps (**Figure 4**) [8]. The following steps need to be followed for replication of the virus. Attachment (mediated by VP4 and VP7), Penetration and uncoating, Synthesis of the plus strand of ssRNA (which also acts as mRNA), Formation of viroplasm, RNA packaging, synthesis of minus-strand and DLP formation, and Virus particle maturation (TLP formation) and release.

#### **5.1 Attachment**

The VP4 or the spike protein is the viral attachment protein of the TLPs. The VP8\* subunit of VP4 (at the tip of the spikes) interacts with the sialoglycans (such as gangliosides GM1 and GD1a) and non-sialoglycans receptors such as histoblood group antigens (HBGAs), receptors present on the host cell [13, 14]. Several integrins (α2β 1, ανβ3, αxβ2, and α4β1) and heat shock protein 70 (hsc70) serve as co-receptors, which interact with VP5\* or VP7 [15]. The VP8\* subunit also mediates hemagglutination in some strains of rotaviruses [10, 16]. The VP4 spike undergoes conformational change the moment it interacts with the host cell receptors leading

*Rotaviral Diseases and Their Implications DOI: http://dx.doi.org/10.5772/intechopen.109466*

#### **Table 1.**

*The number of and size of each gene segment and the functions of their encoded proteins.*

to the exposure of the VP5\* subunit, which is normally hidden under VP8\*. The trypsin facilitates this virus's entry into cells by inducing conformational changes and stabilizing the spike protein.

#### **Figure 4.**

*The rotavirus replication cycle. The rotavirus triple-layered particles (TLPs) first attach to sialo-glycans on the host cell surface, followed by interactions with other cellular receptors (integrins and Hsc70). Virus is then internalized by receptor-mediated endocytosis. Removal of the outer layer, triggered by the low calcium of the endosome, results in the release of transcriptionally active double-layered particles (DLPs) into the cytoplasm. The DLPs start rounds of mRNA transcription, and these mRNAs are used to translate viral proteins. Once enough viral proteins are made, the RNA genome is replicated and packaged into newly made core in specialized structures called viroplasms. Addition of VP6 protein to the core forms the DLPs. The newly made DLPs bind to NSP4, which serves as an endoplasmic reticulum (ER) receptor, and bud into the ER. NSP4 also acts as a viroporin to release Ca2+ from intracellular stores. Transiently enveloped particles are seen in the ER. The transient membranes are removed as the outer capsid proteins VP4 and VP7 assemble, resulting in the maturation of the TLPs. The progeny virions are released through cell lysis.*

#### **5.2 Penetration and uncoating**

After binding, the virusparticles (TLPs) penetrate the host cell either by receptormediated endocytosis or direct membrane penetration. Due to low Ca2+ concentrations in endosomes, the outer capsid proteins (VP4 and VP7) solubilize and release the transcriptionally active DLP form in the cytoplasm of the host cell [17].

#### **5.3 Synthesis of the plus strand of ssRNA and viroplasm formation**

The transcription complexes (RdRp/VP1/Capping enzymeVP3) in the core of the DLPs are complex with the dedicated segment of viral dsRNA [17, 18]. The negative strand of the genomic RNA acts as a template, and the transcription complex synthesizes a capped, non-polyadenylated plus (+) ssRNA, which is released in the cytoplasm via type I aqueous channels [18]. These plus (+) ssRNA transcripts serve two functions. First, they are used for the translation of virus-encoded proteins in the cytoplasm, thus also called mRNA, and later on in the replication cycle, they act as templates for negative-sense strand synthesis and producing dsRNA genome segments [16–18].

#### **5.4 Formation of the viroplasm**

Two non-structural proteins NSP2 and NSP5 mediate the synthesis of virion assembly in cytoplasmic inclusions termed viroplasms. NSP2 octamer forms a complex with VP1, VP2, and tubulin to form viroplasms. The NSP2 octamer has a binding site for which NSP5 and (+)ssRNA compete, thus it regulates the balance between translation and replication [19].

#### **5.5 RNA packaging, synthesis of minus-strand RNA, and DLP formation**

The transcription complex interacts with VP2 decamer, NSP5, and NSP2 and forms the core particle The 11 different (+) ssRNA segments interact with the transcription complex and VP2 and are then packaged [20]. This interaction leads to the synthesis of a negative-sense strand and results in the formation of cores containing a complete set of 11 dsRNA segments. Once formed, VP6 is added to the core leading to the synthesis of DLPs [20].

#### **5.6 Virus particle maturation (TLP formation) and release**

The NSP4 is a transmembrane glycoprotein, located in the endoplasmic reticulum (ER). It interacts with the VP6 protein and acts as an intracellular receptor for DLPs [21]. The NSP4 acts as viroporin as it increases intracellular Ca2+ levels by releasing Ca2+ from intracellular stores. The elevated levels of intracellular Ca2+ are needed to stabilize the outer layer of TLPs, and it activates a kinase-dependent pathway, which leads to autophagy [22]. NSP4 also acts as viral enterotoxin and interacts with noninfected intestinal cells [21, 22]. Interaction of NSP4 and DLP is crucial in the maturation process. The DLPs are recruited to the ER. Budding of DLPs through the ER results in the transient acquisition of a lipid envelope followed by the acquisition of the outermost layers by the addition of VP4 and VP7 to the DLPs. The newly formed TLPs are then released by either cell lysis or exocytosis [8].

#### **5.7 Physical properties**

The outermost layer (VP7 and VP4) of the infectious triple-layer particles (TLPs) can be destabilized with Ca2+-chelating agents, such as EDTA, leading to the loss of the outermost layer and formation of double-layered particles (DLPs). The DPLs are non-infectious. The virion became non-infectious by treating it with 95% ethanol, 0.1% sodium dodecyl sulfate, beta-propiolactone, chlorine, formalin, and phenols. The hemagglutinin activity of VP4 is lost at 45°C or by freezing and thawing [4, 5].

#### **6. Pathogenesis**

Rotaviruses are ubiquitous, and TLPs are relatively stable in the environment. They are transmitted by the fecal-oral route. Fecal contamination of food and water are common reservoirs and fingers, flies and fomites play a vehicular role in the transmission of rotaviruses. Both symptomatic and asymptomatic infections can lead to viral transmission due to the shedding of viruses, often observed in close contact, with day care centers, or via infected food handlers or healthcare workers [23].

The rotaviruses mainly infect the villi of small intestinal mucosa leading to loss of microvilli, villous atrophy, and necrosis of the gut epithelium. The virions extensively replicate in the cytoplasm of enterocytes and damage their transport mechanism resulting in electrolytes and fluid malabsorption leading to increased osmotic pressure in the gut lumen and subsequently onset of diarrhea [8, 24].

The NSP4 protein, encoded by rotaviruses, is a viral enterotoxin that induces calcium ion-dependent chloride secretion into the intestinal lumen via activating signal transduction pathways through phospholipase C. The NSP4 inactivates the Sodium-Glucose-Lactose-Transporter proteins system (SGLT1) that mediates the reabsorption of water, sugar, and body electrolytes. The NSP4 also stimulates the enteric nervous system by inducing the secretion of serotonin (5-HT: 5-hydroxytryptamine) from enteroendocrine cells due to an increase in intracellular calcium concentration, thus increasing gut motility [24, 25].

#### **7. Clinical manifestations**

Rotaviruses are the major cause of diarrheal illness in infants and children worldwide. The infectious dose is low (<100 TLPs), and the incubation period is of 18–36 h followed by acute onset of symptoms. The symptoms vary from mild to severe watery diarrhea, vomiting, abdominal pain, fever, and dehydration. Diarrhea may last for

**Table 2.** *Summary of rotavirus.* *Rotaviral Diseases and Their Implications DOI: http://dx.doi.org/10.5772/intechopen.109466*

5–7 days. The majority of patients usually recover completely. Infected adults are usually asymptomatic or rarely exhibit symptoms. However, infants and children may suffer because of severe loss of fluid and electrolytes leading to dehydration or death if untreated. The excretion of viruses in the stool may persist up to 50 days after the onset of diarrhea (**Table 2**).

#### **8. Epidemiology**

As per WHO, more than 25 million outpatient visits and more than 2 million hospitalizations each year globally are due to severe, dehydrating diarrhea by rotavirus infections in children aged less than 5 years. Generally, the mortality rate is higher in low and middle-income countries as compared with high-income countries. In low and middle-income countries, approximately 75% of children acquire their first episode of rotavirus infection within 12 months of age, whereas children of 2–5 years of age are predominantly infected in high-income countries. The group A rotaviruses (RVA) is the major group that accounts for more than 90% of rotavirus infections in humans worldwide [26]. Rotavirus gastroenteritis is predominantly seen during cool, dry seasons thus also known as "winter diarrhea" and in tropical areas, it can be seen all the year around [27]. Nosocomial outbreaks of rotaviruses are common in pediatric wards, elderly, and immunocompromised patients.

#### **9. Lab diagnosis**

A fresh stool sample should be collected in well-labeled, clean wide-mouth container for the presence of the virus, virus-specific antigen, or RNA by direct or indirect detection methods. Rectal swabs can also be taken, but they are not ideal samples [27].

#### **9.1 Direct method**

The demonstration of the viral particle in stool sample by electron microscopy shows a typical wheel-shaped virion. The sensitivity and specificity can be improved by immune-electron microscopy by adding specific antiviral antibodies to the specimen or by utilizing magnetic microparticles functionalized with monoclonal antibodies to enhance the ability to capture, concentrate, separate, and detect infectiously [28]. The rotavirus can be cultured on cell lines such as monkey kidney cell line to confirm viral viability and also improves the molecular detection of the virus in clinical samples where low viral load is present, although the method is highly sensitive, it is time-consuming, expensive, highly prone to contamination, and is usually available at research-based laboratories [20].

#### **9.2 Indirect method**

Indirect detection of viruses by a variety of molecular assays to detect antigens, antibodies, or viral RNA is more popular, cost-effective, and less time-consuming as compared with direct methods. Commercially available antigen detection kits based on various principles such as immunochromatography or latex agglutination are widely used point-of-care tests for rotavirus diagnosis in resource-limited nations.

The ELISA-based antigen detection techniques are the most widely recognized screening platform with high sensitivity and specificity. A large sample volume can be tested on a 96-well plate [28, 29]. Other immunoassays such as radioimmunoassay, counter-Immuno-electrophoresis, and fluorescent antibody staining are also used.

#### **9.3 Molecular method**

The detection of the rotaviral genome through polymerase chain reaction–based methods (e.g., RT-PCR, RT-qPCR, real-time PCR, and multiplex RT-PCR) are revolutionary as a research tool as well as for diagnosis. Newer PCR-based techniques such as RT-qPCR assays are more sensitive and specific than antigen detection and are suitable for genotyping and sequencing with faster turnaround time as compared with conventional methods [29].

#### **10. Treatment**

The treatment is mainly supportive and consists of rehydration by the oral or intravenous route to restore the loss of water and electrolytes. Commercial preparations of oral rehydration solution (ORS) are available over the counter. To restore the damaged mucosal epithelial lining, the ORS is supplemented with zinc tablets [30].

There is currently no antiviral drug approved for the treatment of rotavirus infections.

There have been studies that demonstrate the anti-rotavirus activity of some drugs such as Nitazoxanide (100 mg in 12–47 months and 200 mg in 4 years old, twice daily for consecutive 3 days) an oralsynthetic anti-parasitic agent inhibits viro plasma formation; gemcitabine, an anticancer drug, with pyrimidine nucleotide inhibitor activity inhibits rotavirus as well. Resveratrol (Inhibitor of viral protein synthesis), Ziyuglycoside II (Inhibitor of TLR4/NF-kB pathway), Brequinar (pyrimidine biosynthesis inhibitor), 20 -*C*-methyl nucleosides (viral polymerase inhibitor), Racecadotril (Intestinal enkephalinase inhibitor, which suppresses the secretion of water and electrolytes into the gut), ML-60218 (RNA polymerase III inhibitors), and Genipin (Entry inhibitor) are potent antiviral drugs [31, 32].

#### **11. Prevention**

General preventive measures:

The rotavirus infection can be prevented by good hygiene measures such as personal hygiene mainly hand and sanitary. Maintenance of food safety standards, safe water supply, and environmental hygiene are essential in preventing outbreaks at food outlets. The WHO recommends continued breastfeeding as maternal antibodies have a protective role and help in reducing the duration and severity of diarrhea [33].

#### **11.1 Rotavirus vaccine**

The rotavirus vaccines that have been licensed by WHO are RotaTeq, Rotarix, Rotavac, and ROTASIIL for the prevention and control of rotavirus gastroenteritis *Rotaviral Diseases and Their Implications DOI: http://dx.doi.org/10.5772/intechopen.109466*

#### *11.1.1 RotaTeq (RV5)*

RotaTeq (RV5) is an oral live attenuated pentavalent vaccine developed by Merck and Co. Inc., USA, and approved by WHO in 2008. RotaTeq is given in three doses at ages 2 months, 4 months, and 6 months. It is a human-bovine reassorted live attenuated vaccine containing four human VP7(G) types (G1, G2, G3, and G4) and one human VP4(P) type. The efficacy of the vaccine in developed nations such as in European countries is higher at 98%; however, the efficacy reduces in low socioeconomic countries such as Asia at 51% and African countries at 64%. Multiple factors such as malnutrition, enteric co-infections, poor maternal health, prevalent strain diversity, and poor maintenance of cold chain storage lead to reduce effectiveness and efficacy of the vaccine in low socioeconomic countries [34, 35].

#### *11.1.2 Rotarix (RV1)*

Rotarix (RV1) is an oral live attenuated monovalent vaccine developed by GlaxoSmithKline Biologicals and approved by WHO in 2009. It is human rotavirus G1P8 genotype months for the prevention of rotavirus gastroenteritis caused by G1 and non-G1 types (G3, G4, and G9). The vaccine is available in lyophilized form, which can be stored at 2°–8°C. It should be used within 24 h of reconstitution in provided diluent. The vaccine is given in two doses (1 ml each) 4 weeks apart. The first dose should be administered before 15 weeks of age, and the two dose series should be completed before 8 months. Similar to RotaTeq, the efficacy reduces to 62–85% in developing countries as compared with developed countries (96%) [36].

#### *11.1.3 Live attenuated, oral vaccine by Bharat Biotech, India, in 2018*

Recently, WHO prequalified another live attenuated, oral vaccine by Bharat Biotech, India, in 2018. It is a monovalent liquid frozen vaccine containing wild-type reassortant G9P11 (116E) strain of rotavirus, prepared in Vero cells. The vaccine is administered as a 3-dose regimen, 4 weeks apart, beginning at 6 weeks of age. The vaccine should not be administered to children older than 8 months of age. The vaccine can be stored at 2–8°C for 7 for months and −20°C for long-term (5 years). The vaccine efficacy is 56.4% (37–70%) in the first year of life in developed countries [37, 38].

#### *11.1.4 Rotasiil*

Rotasiil, developed by the Serum Institute of India, is a pentavalent vaccine containing a lyophilized preparation of live attenuated human-bovine rotavirus reassortant G1, G2, G3, G4, and G9 strains. The vaccine is available in Lyophilized, Thermostable lyophilized and Liquid formulations and thus can be kept at <40°C for up to 18 months and <25°C for up to 30 months. The three doses are given at 6 weeks, 10 weeks, and 14 weeks [38].

#### *11.1.5 Rotavin-M1 (POLYVAC, ThànhphË Hà NÎi, Vietnam) and Lanzhou lamb (Lanzhou Institute of biological product, China)*

Recently, two vaccines have been licensed in Vietnam and India are Rotavin-M1 (POLYVAC, ThànhphË Hà NÎi, Vietnam) and Lanzhou lamb (Lanzhou Institute of biological product, China) respectively though yet to be licensed by WHO, and their coverage is limited [38].

#### *11.1.6 Rotavin-M1*

Rotavin-M1 is a live attenuated human rotavirus strain G1P8 available in the liquid frozen formulation, which can be stored 2–8°C for 2 months and 20°C for 24 months. Two doses are required minimum at 6 weeks of age, for 4 weeks apart. On the other hand, Lanzhou lamb is a live attenuated lamb G10P15 rotavirus strain available in the liquid formulation, which can be stored at 2–8°C for 12 months [37, 38]. The vaccine is given as a single dose followed by annual boosters for children aged between 2 months and 3 years [35]. Rotavirus causes acute gastroenteritis among children less than 5 years of age. Early detection and treatment are crucial to prevent mortality. Improvement in vaccination coverage, safe water supply, personal and environmental hygiene, continued surveillance, and knowledge of circulating genotypes of the virus in the environment are needed.

Rotavac and Rotasiil are manufactured in India, while others are manufactured outside India.

#### **12. Conclusion**

Rotavirus remains the leading cause of severe acute dehydrating diarrhea among infants and young children for four decades with a substantial effect on morbidity and mortality. This infection is primarily localized to the intestinal enterocytes leading to necrosis of mucosal cells by various mechanisms and subsequently secretorydriven watery diarrhea. It is to be expected that together with rotavirus-mediated gastroenteritis such extra-intestinal manifestations will become less prevalent as a consequence of the introduction of anti-rotavirus vaccination. Clinicians, particularly pediatricians caring for rotavirus-infected children, should be aware of the possible extra-intestinal complications of rotavirus infection. The currently available vaccines have significantly reduced mortality in the developed world, but vaccine efficacy, safety, and cost still pose a significant challenge to developing countries. Considering that the attack rate and mortality are relatively higher in developing countries, the control of rotavirus-attributable gastroenteritis mainly relies on vaccine coverage along with good hygienic measures. The introduction and expansion of the use of next-generation RV vaccines with better efficacy, safety, and low cost are necessary along with a multifaceted health approach to address the infections by rotavirus. A new generation of rotavirus vaccines will soon be licensed in many countries and available for more widespread use. Identifying the full value of these vaccines to prevent mortality from rotavirus in developing countries is still several years away and each of the vaccines must first show its effectiveness in poor populations in Africa and Asia. Although many hurdles remain to ascertain the effectiveness of these vaccines in key target populations and their affordability and to remove lingering concerns about safety from intussusception, the presence of two candidate vaccines provides an important new instrument to decrease the morbidity and mortality associated with rotavirus diarrhea.

*Rotaviral Diseases and Their Implications DOI: http://dx.doi.org/10.5772/intechopen.109466*

#### **Author details**

Kirti Nirmal\* and Seema Gangar Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India

\*Address all correspondence to<EMAIL_ADDRESS>
© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] Bishop RF, Davidson GP, et al. Virus particles in epithelial cells of duodenal mucosa from children with viral gastroenteritis. Lancet. 1973;**1**:1281-1283

[2] Available from: https://www.who.int/ westernpacific/health-topics/rotavirusinfections. [Accessed: October 4, 2022]

[3] Carstens EB. Ratification vote on taxonomic proposals to the International Committee on Taxonomy of Viruses (2009). Archives of Virology. 2010;**155**(1):133-146. DOI: 10.1007/ s00705-009-0547-x

[4] Flewett T, Bryden A, Davies H, Woode G, Bridger J, Derrick J. Relation between viruses from acute gastroenteritis of children and newborn calves. The Lancet. 1974;**304**(7872):61- 63. DOI: 10.1016/s0140-6736(74)91631-6

[5] Jayaram H, Estes M, Prasad BVV. Emerging themes in rotavirus cell entry, genome organization, transcription, and replication. Virus Research. 2004;**101**(1):67-81. DOI: 10.1016/j. virusres.2003.12.007

[6] Prasad BV, Burns JW, Marietta E, Estes MK, Chiu W. Localization of VP4 neutralization sites in rotavirus by threedimensional cryo-electron microscopy. Nature. 1990;**343**:476-479

[7] Shaw AL, Rothnagel R, Chen D, Ramig RF, Chiu W, Prasad BV. Threedimensional visualization of the rotavirus hemagglutinin structure. Cell. 1993;**74**:693-701

[8] Estes MK, Greenberg HB. Rotaviruses. In: Knipe DM, Howley PM, et al., editors. Fields Virology. 6th ed. Philadelphia, PA: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2013. pp. 1347-1401

[9] Tihova M, Dryden KA, Bellamy AR, Greenberg HB, Yeager M. Localization of membrane permeabilization and receptor binding sites on the VP4 hemagglutinin of rotavirus: Implications for cell entry. Journal of Molecular Biology. 2001;**314**:985-992

[10] Settembre EC, Chen JZ, Dormitzer PR, Grigorieff N, Harrison SC. Atomic model of an infectious rotavirus particle. EMBO Journal. 2011;**30**(2):408- 416. DOI: 10.1038/emboj.2010.322. Epub 2010 Dec 14

[11] Matthijnssens J, Ciarlet M, Heiman E, Arijs I, Delbeke T, McDonald SM, et al. Full genome-based classification of rotaviruses reveals a common origin between human Wa-Like and porcine rotavirus strains and human DS-1-like and bovine rotavirus strains. Journal of Virology. 2008;**82**(7):3204-3219. DOI: 10.1128/JVI.02257-07. Epub 2008 Jan 23

[12] Cohen J, Laporte J, Charpilienne A, Scherrer R. Activation of rotavirus RNA polymerase by calcium chelation. Archives of Virology. 1979;**60**(3-4):177-186

[13] Guo CT, Nakagomi O, Mochizuki M, Ishida H, Kiso M, Ohta Y, et al. Ganglioside GM(1a) on the cell surfaceis involved in the infection by human rotavirus KUN and MO strains. Journal of Biochemistry. 1999;**126**(October (4)):683-688

[14] Haselhorst T, Fleming FE, Dyason JC, Hartnell RD, Yu X, Holloway G, et al. Sialic acid dependence in rotavirus host cell invasion. Nature Chemical Biology. 2009;**5**(February (2)):91-93

[15] Coulson BS, Londrigan SL, Lee DJ. Rotavirus contains integrin ligand

*Rotaviral Diseases and Their Implications DOI: http://dx.doi.org/10.5772/intechopen.109466*

sequences and a disintegrin-like domain that are implicated in virus entry into cells. Proceedings of the National Academy of Sciences of the United States of America. 1997;**94**(May (10)): 5389-5394

[16] Mackow ER, Barnett JW, Chan H, Greenberg HB. The rhesus rotavirus outer capsid protein VP4 functions as a hemagglutinin and is antigenically conserved when expressed by a baculovirus recombinant. Journal of Virology. 1989;**63**(April (4)):1661-1668

[17] Ludert JE, Michelangeli F, Gil F, Liprandi F, Esparza J. Penetration and uncoating of rotaviruses in cultured cells. Intervirology. 1987;**27**(2):95-101

[18] Periz J, Celma C, Jing B, Pinkney JN, Roy P, Kapanidis AN. Rotavirus mRNAS are released by transcript-specific channels in the double-layered viral capsid. Proceedings of the National Academy of Sciences of the United States of America. 2013;**110**(July (29)): 12042-12047

[19] Silvestri LS, Taraporewala ZF, Patton JT. Rotavirus replication: Plussense templates for double-stranded RNA synthesis are made in viroplasms. Journal of Virology. 2004;**78**(July (14)): 7763-7774

[20] Fabbretti E, Afrikanova I, Vascotto F, Burrone OR. Two nonstructural rotavirus proteins, NSP2 and NSP5, form viroplasm-like structures in vivo. The Journal of General Virology. 1999;**80**(February (Pt 2)):333-339

[21] Berois M, Sapin C, Erk I, Poncet D, Cohen J. Rotavirus nonstructural protein NSP5 interacts with major core protein VP2. Journal of Virology. 2003;**77**(February (3)):1757-1763

[22] Taylor JA, O'Brien JA, Yeager M. The cytoplasmic tail of NSP4, the

endo- plasmic reticulum-localized non-structural glycoprotein of rotavirus, contains distinct virus binding and coiled coil domains. The EMBO Journal. 1996;**15**(September (17)):4469-4476

[23] Crawford SE, Hyser JM, Utama B, Estes MK. Autophagy hijacked through viroporin-activated calcium/calmodulindependent kinase kinase-signaling is required for rotavirus replication. Proceedings of the National Academy of Sciences of the United States of America. 2012;**109**(December (50)):E3405-E3413

[24] Omatola CA, Olaniran AO. Rotaviruses: From pathogenesis to disease control—A critical review. Viruses. 2022;**14**:875. DOI: 10.3390/ v14050875

[25] O'Ryan MG. Clinical Manifestations and Diagnosis of Rotavirus Infection: An Update. Wolters Kluwers. Available from: https://www.uptodate.com/contents/ clinical-manifestations-and-diagnosisof-rotavirus-infection#H3096970958. [Accessed: September 12, 2020]

[26] Bialowas S, Hagbom M, Nordgren J, Karlsson T, Sharma S, Magnusson KE, et al. Rotavirus and serotonin cross-talk in diarrhoea. PLoS One. 2016;**11**:e0159660

[27] Crawford SE, Ramani S, Tate JE, Parashar UD, Svensson L, Hagbom M, et al. Rotavirus infection. Nature Reviews Disease Primers. 2017;**3**:17083

[28] Lestari FB, Vongpunsawad S, Wanlapakorn N, Poovorawan Y. Rotavirus infection in children in Southeast Asia 2008-2018: Disease burden, genotype distribution, seasonality, and vaccination. Journal of Biomedical Science. 2020;**27**:66

[29] Yen C, Cortese MM. Rotaviruses. Principles and Practice of Pediatric

Infectious Diseases. Amsterdam, The Netherlands: Elsevier; 2018. pp. 1122- 1125.e3

[30] World Health Organization (WHO). Rotavirus vaccines: An update. Weekly Epidemiological Record. 2009;**84**:533-537

[31] El Ageery MS, Ali R, NTA EK, Rakha SA, Zeid MS. Comparison of enzyme immunoassay, late x agglutination and polyacrylamide gel electrophoresis for diagnosis of rotavirus in children. Egyptian Journal of Basic and Applied Sciences. 2020;**7**:47-52

[32] Chen S, Wanga Y, Lia P, Yina Y, Bijveldsa MJ, de Jongea HR, et al. Drug screening identifies gemcitabine inhibiting rotavirus through alteration of pyrimidine nucleotide synthesis pathway. Antiviral Research. 2020;**180**:104823

[33] Center for Health Protection (CHP). Health Topics on Rotavirus Infection by the Department of Health, the Government of the Hong Kong Special Administrative Region. 2019. Available from: https://www.chp.gov.hk/en/ healthtopics/content/24/38.html

[34] Soares Weiser K, Bergman H, Henschke N, Pitan F, Cunliffe N. Vaccines for preventing rotavirus diarrhoea: Vaccines in use. Cochrane Database of Systematic Reviews. 2019;**3**:CD008521

[35] Vesikari T, Matson DO, Dennehy P, Van Damme P, Santosham M, Rodriguez Z, et al. Safety and efficacy of a pentavalent human–bovine (WC3) reassortant rotavirus vaccine. The New England Journal of Medicine. 2006;**354**:23-33

[36] Vesikari T, Karvonen A, Prymula R, Schuster V, Tejedor JC, Cohen R, et al. Efficacy of human rotavirus vaccine against rotavirus gastroenteritis during the first 2 years of life in

European infants: Randomised, double-blind controlled study. Lancet. 2007;**370**:1757-1763

[37] Bhandari N, Rongsen-Chandola T, Bavdekar A, John J, Antony K, Taneja S, et al. Efficacy of a monovalent humanbovine (116E) rotavirus vaccine in Indian children in the second year of life. Vaccine. 2014;**32**:A110-A116

[38] World Health Organization. Summary of Key Characteristics of Currently WHO-Pre-Qualified Rotavirus Vaccines, Version 1.4. 2019. Available from: https://www.who.int/ publications/i/item/WHO-IVB-2021.03. [Accessed: November 10, 2022]

#### **Chapter 3**


3. Macrophage migration inhibitory factor (MIF)

MIF is a multifunctional protein, constitutively expressed in a wide variety of immune and nonimmune cells, such as eosinophils, neutrophils, granulocytes, monocytes/macrophages, B and T lymphocytes; endocrine; endothelial; epithelial; and neuronal cells [19].

MIF is a monomer of 115 amino acids forming a homotrimer; each has two antiparallel alpha helices that pack against a four-stranded beta-sheet. Each of the three monomers is arranged to form a barrel containing a channel that runs through the center of the protein along a molecule (Figure 3) [20].

MIF is stored in pre-formed and released rapidly in response to the stimulation from microbial products (LPS), proliferative signals, and hypoxia [18–20], works in a paracrine and autocrine form, promotes the activation of cells, as well as the release of pro-inflammatory cytokines, and counteracts the effects of glucocorticoids at the sites of inflammation [18].

MIF activates in macrophages functions such as phagocytosis, adherence, motility and transendothelial migration [19].

Monocytes/macrophages store large amounts of preformed MIF that are released against stimulation with LPS, glucocorticoids, Gram-positive exotoxins, cytokines, and pro-inflammatory mediators, which have an important role in the local secretion of MIF during the innate immune response [19, 21].

### 3.1 MIF and inflammation

The physiological role of MIF is to counteract the inhibitory effects of steroids on the inflammatory and immune response; MIF is a pro-inflammatory cytokine that

Figure 3. MIF structure. (a) The folding of the MIF monomer and (b) the folded structure of MIF trimer [18].

Immune Response in Gingival Disease: Role of Macrophage Migration Inhibitory Factor DOI: http://dx.doi.org/10.5772/intechopen.82026

stimulates the release of other cytokines, such as TNF-α, IFN-γ, IL-1β, IL-6, IL-8, and IL-12 in inflammation [19].

MIF also participate in the modulation of the expression of other proinflammatory molecules, including the same MIF, nitric oxide and cyclooxygenase 2 (COX-2), and prostaglandin 2 (PGE2), perpetuating the inflammatory environment, by positive feedback to the inflammatory response [22, 23].

MIF plays a critical role in the regulation of the innate immune response, through the modulation of TLR4. Activation of TLR4 results in the production of pro-inflammatory mediators, including MIF, which induces the recruitment of inflammatory cells, including neutrophils [19].

#### 3.2 MIF chemotactic activity

osteoclastogenesis begins by the binding of RANK-RANKL and can be interrupted by OPG that functions as a decoy receptor that blocks the binding of RANKL to

Gingival Disease - A Professional Approach for Treatment and Prevention

The pro-inflammatory cytokines are proteins that have a principal role in the control, direction, amplitude, and duration of the immune response. They allow contact within the immune system and communication with other organs and tissue systems [8]. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine; MIF is an important mediator of the innate immune response [18]; however, there are a few studies that describe its participation in PE, for its characteristics it can lead the environment of the inflammatory response in the disease.

MIF is a multifunctional protein, constitutively expressed in a wide variety of immune and nonimmune cells, such as eosinophils, neutrophils, granulocytes, monocytes/macrophages, B and T lymphocytes; endocrine; endothelial; epithelial;

MIF is a monomer of 115 amino acids forming a homotrimer; each has two antiparallel alpha helices that pack against a four-stranded beta-sheet. Each of the three monomers is arranged to form a barrel containing a channel that runs through

MIF is stored in pre-formed and released rapidly in response to the stimulation from microbial products (LPS), proliferative signals, and hypoxia [18–20], works in a paracrine and autocrine form, promotes the activation of cells, as well as the release of pro-inflammatory cytokines, and counteracts the effects of glucocorti-

MIF activates in macrophages functions such as phagocytosis, adherence, motil-

Monocytes/macrophages store large amounts of preformed MIF that are released against stimulation with LPS, glucocorticoids, Gram-positive exotoxins, cytokines, and pro-inflammatory mediators, which have an important role in the local secre-

The physiological role of MIF is to counteract the inhibitory effects of steroids on the inflammatory and immune response; MIF is a pro-inflammatory cytokine that

MIF structure. (a) The folding of the MIF monomer and (b) the folded structure of MIF trimer [18].

3. Macrophage migration inhibitory factor (MIF)

the center of the protein along a molecule (Figure 3) [20].

tion of MIF during the innate immune response [19, 21].

RANK (Figure 2) [17].

and neuronal cells [19].

coids at the sites of inflammation [18].

ity and transendothelial migration [19].

3.1 MIF and inflammation

Figure 3.

48

Although MIF was identified for the first time as an inhibitor of macrophage migration, subsequent studies revealed that in the presence of inflammatory mediators, it is also capable of leukocyte extravasation [24]. This cytokine can have a similar function to chemokines while it is in interaction with the chemokine receptors CXCR4 and CXCR2 to promote the recruitment of inflammatory cells [19].

In this way, MIF participates in the adhesion of monocytes to the vessel wall and its transendothelial migration [25]. This immobilization of cells to the endothelial surface is mediated by the action of chemokines that prevent these cells from continuing their circulation, promoting the immobilization and transmigration of the cells through the endothelium [26].

### 3.3 MIF and periodontal disease

The pro-inflammatory, chemoattractant, and osteoclastogenic characteristics of MIF make it a cytokine with an important role both in the initiation and progression of periodontal disease (Figure 4).

The studies related to MIF and periodontal disease are few; however, the existing ones have given the guidelines to introduce this cytokine to its pathophysiology.

#### 3.3.1 MIF expression in gingival tissue

As mentioned above, MIF is a cytokine produced by immune and nonimmune cells; therefore the source of MIF in periodontal tissues can be diverse including inflammatory cells as cells resident in tissues [19].

Figure 4. MIF in periodontal disease.

In 2003, the presence of MIF in epithelial cells, keratinocytes, and fibroblasts of gingival tissue was first described by immunohistochemistry [27], confirming that this cytokine is located preformed in the cytoplasm of the cell [21], therefore MIF could participate in homeostatic, proliferative (necessary for the cell), and inflammatory functions in the tissue [27].

Another study in a murine model of acute apical PE analyzed the coexpression of MIF and RANKL in periapical lesions induced in mice, where the author associates that the presence of MIF increases the pro-inflammatory environment that promotes the overexpression of RANKL, the inducer of the direct activation of the

Immune Response in Gingival Disease: Role of Macrophage Migration Inhibitory Factor

The osteoclastogenic activity of MIF in PE can also be attributed to the ability of the cytokine to activate signaling pathways such as NF-kB and NFAT in osteoclast precursors that initiate differentiation and survival in the cell [37, 38], as well as the possible chemoattractant faculty of MIF by acting as a ligand for the chemokine

In periodontal disease MIF regulates the immune response and can promote soft

Due to the few studies about MIF and periodontal disease it is important to continue doing more research to elucidate the participation of this cytokine in the

receptor CXCR4 in the recruitment of osteoclast precursor cells [39].

The authors declare that they have no conflicts of interest.

osteoclasts [36].

4. Conclusion

tissue degradation and bone resorption.

DOI: http://dx.doi.org/10.5772/intechopen.82026

immunopathology of this disease.

GCF gingival crevicular fluid

PE periodontitis

MIF macrophage migration inhibiting factor

RANK receptor activator of nuclear factor-kappa B RANKL receptor activator of nuclear factor-kappa B ligand

Conflict of interest

Abbreviation

51

Likewise, Li et al. evaluated the expression of MIF in gum biopsies of subjects with PE where they found the presence of MIF in both epithelial strata and in connective tissue vessels; it was also determined that reconstituted gingival epithelial cells overexpress MIF when performing stimulations with LPS [28]. Therefore, the expression profile of MIF can be regulated by the periodontal conditions and the presence of endotoxins that induce its release [21].

#### 3.3.2 MIF in gingival crevicular fluid

The evaluation of MIF in body fluids as a biological indicator has been carried out in various pathologies. Recently the gingival crevicular fluid (GCF) has received a lot of attention for being an informative fluid of both physiological and pathological events in the oral cavity.

In 2009 the concentrations of MIF in GCF of subjects with induced gingivitis were determined where it is verified that the levels of MIF can be modified in response to bacterial colonization in the gingival sulcus [29], this being the first work in describing the cytokine in this fluid.

Another study evaluated the MIF concentrations in GCF of patients with metabolic syndrome with gingivitis. This study found that the group with both pathologies does not present significant differences with the group that presents only gingivitis; nevertheless, it found differences in comparison with healthy subjects, and therefore the authors related the increase of MIF directly with the gingival inflammation and not with the presence of the metabolic syndrome [30].

#### 3.3.3 MIF in saliva and serum

Research on the quantification of MIF in saliva has been increasing in various pathologies such as oral squamous cell carcinoma [31], in studies evaluating depressive symptoms [32], and in chronic pelvic pain syndrome [33], among others.

The investigations about MIF serum concentrations are extensive because this fluid has been used to evaluate MIF in numerous systemic diseases.

In 2017 MIF was evaluated in saliva and serum in aggressive PE, this study was first to report this cytokine in both fluids in periodontal disease. Their results showed that the cytokine increased significantly due to the presence of the disease in both fluids, likewise MIF correlated with clinical diagnostic parameters [34].

Knowing the concentrations of MIF in different fluids in periodontal disease would provide us the information necessary to know the behavior of the protein at the local and systemic levels in the presence of this type of entity.

#### 3.3.4 MIF experimental studies

An experimental study in a murine model of PE showed that in MIF / mice, the absence of MIF decreases the clinical signs of the disease and the recruitment and phagocytic activity of neutrophils. It also points out that MIF is important in the control of infection because the lack of the cytokine increases the bacterial load and decreases the production of inflammatory cytokines in MIF / mice compared to wild-type mice [35].

Immune Response in Gingival Disease: Role of Macrophage Migration Inhibitory Factor DOI: http://dx.doi.org/10.5772/intechopen.82026

Another study in a murine model of acute apical PE analyzed the coexpression of MIF and RANKL in periapical lesions induced in mice, where the author associates that the presence of MIF increases the pro-inflammatory environment that promotes the overexpression of RANKL, the inducer of the direct activation of the osteoclasts [36].

The osteoclastogenic activity of MIF in PE can also be attributed to the ability of the cytokine to activate signaling pathways such as NF-kB and NFAT in osteoclast precursors that initiate differentiation and survival in the cell [37, 38], as well as the possible chemoattractant faculty of MIF by acting as a ligand for the chemokine receptor CXCR4 in the recruitment of osteoclast precursor cells [39].

## 4. Conclusion

In 2003, the presence of MIF in epithelial cells, keratinocytes, and fibroblasts of gingival tissue was first described by immunohistochemistry [27], confirming that this cytokine is located preformed in the cytoplasm of the cell [21], therefore MIF could participate in homeostatic, proliferative (necessary for the cell), and inflam-

Gingival Disease - A Professional Approach for Treatment and Prevention

Likewise, Li et al. evaluated the expression of MIF in gum biopsies of subjects with PE where they found the presence of MIF in both epithelial strata and in connective tissue vessels; it was also determined that reconstituted gingival epithelial cells overexpress MIF when performing stimulations with LPS [28]. Therefore, the expression profile of MIF can be regulated by the periodontal conditions and the

The evaluation of MIF in body fluids as a biological indicator has been carried out in various pathologies. Recently the gingival crevicular fluid (GCF) has received a lot of attention for being an informative fluid of both physiological and patholog-

In 2009 the concentrations of MIF in GCF of subjects with induced gingivitis were determined where it is verified that the levels of MIF can be modified in response to bacterial colonization in the gingival sulcus [29], this being the first

Another study evaluated the MIF concentrations in GCF of patients with metabolic syndrome with gingivitis. This study found that the group with both pathologies does not present significant differences with the group that presents only gingivitis; nevertheless, it found differences in comparison with healthy subjects, and therefore the authors related the increase of MIF directly with the gingival inflammation and not with the presence of the metabolic syndrome [30].

Research on the quantification of MIF in saliva has been increasing in various

depressive symptoms [32], and in chronic pelvic pain syndrome [33], among others. The investigations about MIF serum concentrations are extensive because this

In 2017 MIF was evaluated in saliva and serum in aggressive PE, this study was

An experimental study in a murine model of PE showed that in MIF / mice, the absence of MIF decreases the clinical signs of the disease and the recruitment and phagocytic activity of neutrophils. It also points out that MIF is important in the control of infection because the lack of the cytokine increases the bacterial load and decreases the production of inflammatory cytokines in MIF / mice compared to

pathologies such as oral squamous cell carcinoma [31], in studies evaluating

first to report this cytokine in both fluids in periodontal disease. Their results showed that the cytokine increased significantly due to the presence of the disease in both fluids, likewise MIF correlated with clinical diagnostic parameters [34]. Knowing the concentrations of MIF in different fluids in periodontal disease would provide us the information necessary to know the behavior of the protein at

fluid has been used to evaluate MIF in numerous systemic diseases.

the local and systemic levels in the presence of this type of entity.

matory functions in the tissue [27].

3.3.2 MIF in gingival crevicular fluid

ical events in the oral cavity.

3.3.3 MIF in saliva and serum

3.3.4 MIF experimental studies

wild-type mice [35].

50

presence of endotoxins that induce its release [21].

work in describing the cytokine in this fluid.

In periodontal disease MIF regulates the immune response and can promote soft tissue degradation and bone resorption.

Due to the few studies about MIF and periodontal disease it is important to continue doing more research to elucidate the participation of this cytokine in the immunopathology of this disease.