*Review* **The Role of the Human Microbiome in the Pathogenesis of Pain**

**Klaudia Ustianowska 1, Łukasz Ustianowski 1, Filip Machaj 1,2, Anna Gor ˛acy 3, Jakub Rosik 1,4, Bartosz Szostak 1, Joanna Szostak 5 and Andrzej Pawlik 1,\***

**Abstract:** Understanding of the gut microbiome's role in human physiology developed rapidly in recent years. Moreover, any alteration of this microenvironment could lead to a pathophysiological reaction of numerous organs. It results from the bidirectional communication of the gastrointestinal tract with the central nervous system, called the gut–brain axis. The signals in the gut–brain axis are mediated by immunological, hormonal, and neural pathways. However, it is also influenced by microorganisms in the gut. The disturbances in the gut–brain axis are associated with gastrointestinal syndromes, but recently their role in the development of different types of pain was reported. The gut microbiome could be the factor in the central sensitization of chronic pain by regulating microglia, astrocytes, and immune cells. Dysbiosis could lead to incorrect immune responses, resulting in the development of inflammatory pain such as endometriosis. Furthermore, chronic visceral pain, associated with functional gastrointestinal disorders, could result from a disruption in the gut microenvironment. Any alteration in the gut–brain axis could also trigger migraine attacks by affecting cytokine expression. Understanding the gut microbiome's role in pain pathophysiology leads to the development of analgetic therapies targeting microorganisms. Probiotics, FODMAP diet, and fecal microbiota transplantation are reported to be beneficial in treating visceral pain.

**Keywords:** microbiome; pain; IBS; neuropathy


**Abstract**

For the fabrication of thin films, Physical Vapor Deposition (PVD) techniques specified greater contribution than all other deposition techniques. Laser Ablation or Pulsed Laser deposition (PLD) technique is the one of most promising techniques for the fabrication of thin films among all other physical vapor deposition. In particular, flexible thin-film energy storage fabrication PLD plays an important role due to its special parameters such as fine thickness control, partial pressure atmospheric condition, pulsed repetition rate, in-situ annealing and microstructure optimization. Very recently, thin film supercapbatteries have been broadly studied, in which the battery and supercapacitor based electrodes are combined to obtain a high specific power and specific energy density and extended cycle stability. In order to fabricate thin film supercapbatteries, electrodes that have a large potential window, high capacitance, and capacity performance are vastly desired. Thus, the presented chapter represents an important enhancement in the growth of economical and eco-friendly thin flexible supercapbatteries and confirms their potential in sensible applications such as transport electronics devices and other gadgets.

**Keywords:** pulsed laser deposition, thin film supercapbatteries, micro electronics devices, semi solid state electrolytes, volumetric specific capacities


**2. Endoscopic assessment of polyp histology**

The key factor in adopting the "resect and discard" strategy is the endoscopic evaluation of polyp histology, since this information is necessary to plan the next surveillance interval. Moreover, the presence of suspicious endoscopic features may prompt a polyp to be submit‐ ted to pathologic assessment. Therefore, a reliable endoscopic method of evaluating histolo‐ gy is needed.

In recent years several imaging-enhancing technologies have emerged as an adjuvant for di‐ agnosing and evaluating colorectal lesions [34]. High-resolution and magnification endo‐ scopes allow enlarging the image and discriminating details. These endoscopes are often used in combination with chromoendoscopy, which involves the topical application of dyes at the time of endoscopy to enhance tissue characterization. Narrow-band imaging (NBI) is a technology that applies narrow-bandwidth filters to white light endoscopy allowing dis‐ crimination of mucosal vascular net. Fuji Intelligent Color Enhancement (FICE) and i-Scan are based on the same physical principles as NBI but are not depending on optical filters but on a postprocessing image system. All these technologies have been evaluated in the predic‐ tion of histology of colon polyps.

#### **2.1. High-resolution/magnification endoscopy and chromoendoscopy**

The usefulness of this technology in assessing histology is based on the pit-pattern classifica‐ tion proposed by Kudo which is intended to differentiate between non-neoplastic, neoplas‐ tic and malignant polyps. Following this classification patterns I and II correspond to nonneoplastic lesions and patterns III to V to neoplastic ones. Type V suggests malignant transformation [35].

Several large case series evaluate the utility of pit-pattern analysis to differentiate neoplastic from non-neoplastic lesions. Generally speaking, positive predictive values (PPV) for neo‐ plastic lesion range between 70 to 100% and negative predictive values (NPV) between 70 and 99%. Studies with the largest number of lesions show an overall accuracy of 80-95% [36-38]. One study focused in diminutive lesions, reported an overall accuracy of 95% [39]. There are also some randomized controlled trials comparing magnification plus chromoen‐ doscopy to conventional chromoendoscopy. Konishi et al. [40] showed an accuracy of mag‐ nification colonoscopy in distinguishing non-neoplastic from neoplastic lesions < 10 mm in size of 92% vs 68% for conventional chromoendoscopy. Emura el al. [41] using a similar de‐ sign showing an overall accuracy of 95% vs 84%. These figures were similar whenthe sub‐ group of lesions ≤ 5 mm was analyzed. Conventional colonoscopy, chromoendoscopy and magnification chromoendoscopy were compared in the study by Fu et al. [42], and the latter was found to have the highest accuracy (95.6%).

Magnification chromoendoscopy has also been evaluated in the prediction of malignant his‐ tology and invasive depth of cancer with variable results. Overall, it seems that its sensitivi‐ ty and accuracy are lower. For instance, Bianco et al. [43] showed that endoscopic differentiation between invasive and noninvasive neoplasm had a PPV of 79% and a NPV of 95%. Hurlstone et al. reported an accuracy of 78% and a specificity of 50% [44]. Some au‐ thors use a modification of the Kudo classification with different subtypes of the type V pat‐ tern that may be quite cumbersome to use [45].

In conclusion, high-magnification chromoendoscopy allows the prediction of histology even in small and diminutive lesions, but is better differentiating nonneoplastic from neoplastic lesions than differentiating invasive from noninvasive neoplasms. Moreover, it must be kept in mind that overall accuracy is not 100%, despite the fact that a technology with a NPV of 95% for adenomatous histology fulfils the PIVI criteria for leaving suspected rectosigmoid hyperplastic polyps ≤ 5 mm in size in place [33].

#### **2.2. Narrow-band imaging**

resolution photograph and the polyp then would be resected and discarded. The endoscopic assessment of histology would be used to make an immediate recommendation regarding the next colonoscopy surveillance interval. Finally, when multiple diminutive rectosigmoid hyperplastic polyps are suspected endoscopically, histology can be established by real-time endoscopic assessment and documented by photography without the need of resection and

The key factor in adopting the "resect and discard" strategy is the endoscopic evaluation of polyp histology, since this information is necessary to plan the next surveillance interval. Moreover, the presence of suspicious endoscopic features may prompt a polyp to be submit‐ ted to pathologic assessment. Therefore, a reliable endoscopic method of evaluating histolo‐

In recent years several imaging-enhancing technologies have emerged as an adjuvant for di‐ agnosing and evaluating colorectal lesions [34]. High-resolution and magnification endo‐ scopes allow enlarging the image and discriminating details. These endoscopes are often used in combination with chromoendoscopy, which involves the topical application of dyes at the time of endoscopy to enhance tissue characterization. Narrow-band imaging (NBI) is a technology that applies narrow-bandwidth filters to white light endoscopy allowing dis‐ crimination of mucosal vascular net. Fuji Intelligent Color Enhancement (FICE) and i-Scan are based on the same physical principles as NBI but are not depending on optical filters but on a postprocessing image system. All these technologies have been evaluated in the predic‐

The usefulness of this technology in assessing histology is based on the pit-pattern classifica‐ tion proposed by Kudo which is intended to differentiate between non-neoplastic, neoplas‐ tic and malignant polyps. Following this classification patterns I and II correspond to nonneoplastic lesions and patterns III to V to neoplastic ones. Type V suggests malignant

Several large case series evaluate the utility of pit-pattern analysis to differentiate neoplastic from non-neoplastic lesions. Generally speaking, positive predictive values (PPV) for neo‐ plastic lesion range between 70 to 100% and negative predictive values (NPV) between 70 and 99%. Studies with the largest number of lesions show an overall accuracy of 80-95% [36-38]. One study focused in diminutive lesions, reported an overall accuracy of 95% [39]. There are also some randomized controlled trials comparing magnification plus chromoen‐ doscopy to conventional chromoendoscopy. Konishi et al. [40] showed an accuracy of mag‐ nification colonoscopy in distinguishing non-neoplastic from neoplastic lesions < 10 mm in size of 92% vs 68% for conventional chromoendoscopy. Emura el al. [41] using a similar de‐ sign showing an overall accuracy of 95% vs 84%. These figures were similar whenthe sub‐

**2.1. High-resolution/magnification endoscopy and chromoendoscopy**

pathological evaluation [33].

tion of histology of colon polyps.

transformation [35].

gy is needed.

**2. Endoscopic assessment of polyp histology**

180 Colonoscopy and Colorectal Cancer Screening - Future Directions

#### *2.2.1. Predicting histology by means of vascular features*

Angiogenesis is a main step in the progression of neoplasms; therefore the diagnosis based on vascular morphological changes seems ideal for early detection and diagnosis of co‐ lon neoplasms. NBI enhances the visibility of the capillary network on the surface layer of the mucosa.

Normal mucosa displays a regular hexagonal or honeycomb-like pattern of capillary vessels around the crypt of the gland. This capillary meshwork, named meshed capillary (MC), is invisible or faintly visible (Figure 2a). In the neoplastic lesion, vessels grow thicker, with increasing diameter size, disruption and rise of vessel density as the lesion progresses. There‐ fore, recognizing the lesion becomes easier because it appears as a brownish area (Figure 2b).

**Figure 2.** NBI image of normal mucosa (a) and a diminutive adenoma (b)

Several studies have evaluated the performance of NBI in characterizing colorectal lesions, focusing in the characteristics of the vascular capillary network. Generally speaking, NBI sensitivity and specificity for diagnosing neoplastic lesions ranges between 77% and 99% and 59 – 100% respectively (table 2). This heterogeneity may be explained by the use of dif‐ ferent descriptions of vascular networks. Examples are, brown blob or dense vascular net‐ work to predict neoplasia [46-48]; fine capillary network, dark dots, light rounds, tubular or gyrus like [49]; microvessel thickness (invisible, thin, thick) and microvessel irregularity (in‐ visible, regular, mildly irregular, severely irregular) [50]; vascular patter intensity (weaker, the same or darker than the surrounding mucosa) [51]; fine vascular network or dilated corkscrew type vessels and abnormal branching patterns [52]; and finally, capillary pattern (CP type I: invisible or faintly visible, CP type II: capillaries elongated and thicker and CP type III: capillaries of irregular sizes, thicker and branched) [53-55].Other causes of heteroge‐ neity are the use of magnification or high-resolution endoscopes since the results with the latter are not as encouraging (see section 2.2.5) [46,49,56], and finally, better results are re‐ ported by experts.

**Author Mag Patients/**

Values for each observer are shown.

AC: diagnostic accuracy.

**Author Mag Patients/**

*2.2.3. Predicting submucosal invasion*

**Lesions**

**Sensitivity (%) Specificity (%) PPV**

In vivo Optical Diagnosis of Polyp Histology: Can We Omit Pathological Examination of Diminutive Polyps?

**Sensitivity (%) Specificity (%) PPV**

Chiu [46] a Yes/No 133/180 87-95 88-72 96-92 67-80 87-90 Sano [53] Yes 92/150 96 92 97 90 95 Hirata [50] Yes 163/189 99 90 99 90 98 Hirata [48] Yes 99/148 99 94 99 94 99 Rastogi [49] No 40/123 96 86 90 95 92 Kanao [55] Yes 223/289 95 100 100 20 99 Henry [54] No 42/126 93 88 909 91 91 Ignjatovic [56] Yes/No 48/80 93-74 59-56 - - 76-85

**Table 2.** Vascular pattern analysis with NBI for prediction of adenomatous histology. Mag: use of optical magnification; PPV: positive predictive value; NPV: negative predictive value; DA: diagnostic accuracy. a

Machida [57] Yes 34/43 100 75 91 100 93 East [51] a Yes 20/33 86-77 80-60 - - 84-72 Tischendorf [52] Yes 99/200 90 89 93 84 90 Van den Broek [59] Yes 100/208 90 70 69 90 78

observer are shown. Mag: use of optical magnification; PPV: positive predictive value; NPV: negative predictive value;

A systematic review which included 6 reports published until 2008 comparing NBI (pit pat‐ tern and vascular assessment) and chromoendoscopy showed a pooled sensitivity, specifici‐

NBI has also been evaluated to diagnose early colorectal neoplasia and submucosal inva‐ sion. Katagiri et al. [61] used the capillary pattern classification in colon adenomas. Those showing CP type III harbored HGD or invasive cancer. In a recent report this group further developed this classification expanding CP type III in group IIIA (visible microvascular ar‐ chitecture and high microvessel density with lack of uniformity, branching and curtailed ir‐ regularity) and group IIIB (nearly avascular or loose microvascular area). This detailed classification allowed differentiation between lesions with Sm1 submucosal invasion from Sm2-Sm3 with a sensitivity, specificity and diagnostic accuracy of 84.8%, 88.7% and 87.7% respectively [62]. Hirata et al.[50] found that the accuracy of diagnosis of submucosal mas‐

**Lesions**

**Table 3.** Pit pattern analysis with NBI for prediction of adenomatous histology a

ty and overall accuracy of 92%, 86% and 89% respectively [60].

**(%)**

**(%)**

Two observers. Values for each

**NPV (%)**

**NPV (%)**

http://dx.doi.org/10.5772/53205

**DA (%)** 183

Two observers.

**DA (%)**

#### *2.2.2. Predicting histology by means of pit pattern evaluation*

Most of the published studies, mainly from Japan, use optical magnification in combination with NBI, and the performance of pit pattern analysis with NBI ha salso been assessed (table 3). Sensitivity for neoplastic lesion ranges between 86 and 100%, while specificity ranges be‐ tween 84 and 100%. Some studies have compared NBI with chromoendoscopy showing sim‐ ilar diagnostic accuracy, suggesting that NBI could replace chromoendoscopy in the diagnostic evaluation of colon lesions [46, 47, 52]. However, the original pit pattern classifi‐ cation was not designed for NBI, and has not been validated for this purpose. NBI funda‐ mentals are different that those of chromoendoscopy. The latter uses dyes that lie inside the pits or stain their edges depending on the stain used while NBI highlights the capillary plexus that surrounds the opening of each pit. Machida et al. [57] described the use of NBI with magnification for pit pattern classification, showing that NBI was superior to conven‐ tional colonoscopy for pit pattern delineation but inferior to chromoendoscopy. The correla‐ tion between pit pattern analysis using chromoendoscopy and NBI is far from perfect especially for the pattern with the upmost clinical importance, type V. A study compared the pit pattern analysis obtained by NBI with stereoscopic examination and showed that the correlation was only 57% for type VN[58]. East et al. [51] found a kappa score of only 0.23 between both types of pit pattern evaluation. Better results were obtained by Hirata et al. [48] (78% of agreement for pit pattern VI and 100% for VN).

In vivo Optical Diagnosis of Polyp Histology: Can We Omit Pathological Examination of Diminutive Polyps? http://dx.doi.org/10.5772/53205 183

**Table 2.** Vascular pattern analysis with NBI for prediction of adenomatous histology. Mag: use of optical magnification; PPV: positive predictive value; NPV: negative predictive value; DA: diagnostic accuracy. a Two observers. Values for each observer are shown.

**Table 3.** Pit pattern analysis with NBI for prediction of adenomatous histology a Two observers. Values for each observer are shown. Mag: use of optical magnification; PPV: positive predictive value; NPV: negative predictive value; AC: diagnostic accuracy.

A systematic review which included 6 reports published until 2008 comparing NBI (pit pat‐ tern and vascular assessment) and chromoendoscopy showed a pooled sensitivity, specifici‐ ty and overall accuracy of 92%, 86% and 89% respectively [60].

#### *2.2.3. Predicting submucosal invasion*

Several studies have evaluated the performance of NBI in characterizing colorectal lesions, focusing in the characteristics of the vascular capillary network. Generally speaking, NBI sensitivity and specificity for diagnosing neoplastic lesions ranges between 77% and 99% and 59 – 100% respectively (table 2). This heterogeneity may be explained by the use of dif‐ ferent descriptions of vascular networks. Examples are, brown blob or dense vascular net‐ work to predict neoplasia [46-48]; fine capillary network, dark dots, light rounds, tubular or gyrus like [49]; microvessel thickness (invisible, thin, thick) and microvessel irregularity (in‐ visible, regular, mildly irregular, severely irregular) [50]; vascular patter intensity (weaker, the same or darker than the surrounding mucosa) [51]; fine vascular network or dilated corkscrew type vessels and abnormal branching patterns [52]; and finally, capillary pattern (CP type I: invisible or faintly visible, CP type II: capillaries elongated and thicker and CP type III: capillaries of irregular sizes, thicker and branched) [53-55].Other causes of heteroge‐ neity are the use of magnification or high-resolution endoscopes since the results with the latter are not as encouraging (see section 2.2.5) [46,49,56], and finally, better results are re‐

Most of the published studies, mainly from Japan, use optical magnification in combination with NBI, and the performance of pit pattern analysis with NBI ha salso been assessed (table 3). Sensitivity for neoplastic lesion ranges between 86 and 100%, while specificity ranges be‐ tween 84 and 100%. Some studies have compared NBI with chromoendoscopy showing sim‐ ilar diagnostic accuracy, suggesting that NBI could replace chromoendoscopy in the diagnostic evaluation of colon lesions [46, 47, 52]. However, the original pit pattern classifi‐ cation was not designed for NBI, and has not been validated for this purpose. NBI funda‐ mentals are different that those of chromoendoscopy. The latter uses dyes that lie inside the pits or stain their edges depending on the stain used while NBI highlights the capillary plexus that surrounds the opening of each pit. Machida et al. [57] described the use of NBI with magnification for pit pattern classification, showing that NBI was superior to conven‐ tional colonoscopy for pit pattern delineation but inferior to chromoendoscopy. The correla‐ tion between pit pattern analysis using chromoendoscopy and NBI is far from perfect especially for the pattern with the upmost clinical importance, type V. A study compared the pit pattern analysis obtained by NBI with stereoscopic examination and showed that the correlation was only 57% for type VN[58]. East et al. [51] found a kappa score of only 0.23 between both types of pit pattern evaluation. Better results were obtained by Hirata et al.

**Sensitivity (%) Specificity (%) PPV**

**(%)**

**NPV (%)**

**DA (%)**

ported by experts.

*2.2.2. Predicting histology by means of pit pattern evaluation*

182 Colonoscopy and Colorectal Cancer Screening - Future Directions

[48] (78% of agreement for pit pattern VI and 100% for VN).

**Lesions**

Su [47] Yes 78/110 96 87 93 92 92 Tischendorf [52] Yes 99/200 94 89 94 89 92 East [51] a Yes 30/33 77-91 50-60 - - 69-81

**Author Mag Patients/**

NBI has also been evaluated to diagnose early colorectal neoplasia and submucosal inva‐ sion. Katagiri et al. [61] used the capillary pattern classification in colon adenomas. Those showing CP type III harbored HGD or invasive cancer. In a recent report this group further developed this classification expanding CP type III in group IIIA (visible microvascular ar‐ chitecture and high microvessel density with lack of uniformity, branching and curtailed ir‐ regularity) and group IIIB (nearly avascular or loose microvascular area). This detailed classification allowed differentiation between lesions with Sm1 submucosal invasion from Sm2-Sm3 with a sensitivity, specificity and diagnostic accuracy of 84.8%, 88.7% and 87.7% respectively [62]. Hirata et al.[50] found that the accuracy of diagnosis of submucosal mas‐ sive invasion on the basis of thick and severely irregular vascular pattern was 100%. Kanao et al. [55] used a combination of capillary pattern and pit pattern and showed that lesions with irregular microvessels with variable sizes and distribution, and pit absence with avas‐ cular areas harbored more often massive submucosal invasion.

**Author Predictive of adenoma Predictive of hyperplastic**

Fine capillary network alone but absent mucosal

http://dx.doi.org/10.5772/53205

185

Circular pattern with dots (central dark area

Pattern of black dots surrounded by white

Thin blood vessels coursing across polyp surface, and

Non-neoplastic pit pattern (circular pit pattern)

surrounded by a lighter area)

Bland, featureless appearance

not surrounding pits

No vascular markins

pattern

In vivo Optical Diagnosis of Polyp Histology: Can We Omit Pathological Examination of Diminutive Polyps?

 Prediction of histology using NBI without magnification

*2.2.6. Prediction of histology of diminutive polyps*

Tubular or oval pits, variable size pits

Straight blood vessels around pits forming

Rogart [68] Modified Kudo´s classification Vascular color intensity (light, medium, dark)

The group of the Indiana University has very recently designed a simple classification for determination of polyp histology (NICE classification) and has validated it for its use by ex‐ perienced and non-experienced examinators (table 5) [70]. Further studies are needed to

Some authors have evaluated de diagnostic accuracy of NBI on diminutive polyps showing similar results to those on polyps of any size. In a study by Rex [67] the sensitivity of NBI in diagnosing adenomas was 92%, specificity 87%, PPV was 88%, NPV 91% and accuracy 89%. Grading the confidence on the endoscopic diagnosis in high and low, high confidence pre‐ dictions of adenomas were correct in 92% of polyps and in 91% of ≤ 5 mm polyps. The equivalent figures for hyperplastic prediction were 95%. The same group evaluated the per‐ formance of NBI in real time for distal colorectal polyps, and showed a sensitivity of 96%, a specificity of 99.4%, and NPV and PPV of 99.4% and 96% respectively [71]. The authors con‐ cluded that NBI is sufficiently accurate to allow distal hyperplastic polyps to be left in place without resection and small, distal adenomas to be discarded without pathologic assess‐ ment. In the study of Henry et al. [54] the sensitivity for predicting histology was 87%, spe‐ cificity was 93%, PPV was 89%, NPV was 91% and overall accuracy was 90%. Paggy et al. [72] found similar results both in the whole group of < 10 mm polyps and in diminutive pol‐ yps. Other authors have not showed as good results [56,73]. The most recent report using the NICE classification found an accuracy of 89%, sensitivity of 98% and a NPV of 95%. In conclusion, diagnostic accuracy of endoscopic prediction of histology of diminutive polyps

evaluate the reproducibility of this classification in real-time endoscopy.

seems equivalent to that of larger polyps, at least in expert hands.

Rex [67] Overall brown color

Rastogi [49, 65,

66]

#### *2.2.4. NBI compared with other diagnostic modalities*

NBI has been compared with other image enhancing technologies, most frequently with chromoendoscopy. Overall, the diagnostic accuracy of NBI is better than that of convention‐ al colonoscopy and equivalent to that of chromoendoscopy (figure 3) [46,47,52], especially if vascular assessment rather than pit pattern is used [51].

**Figure 3.** Invasive carcinoma in a depressed lesion observed with white light (a), NBI (b), and chromoendoscopy (c)

Four recent studies perform an evaluation of endoscopic trimodal imaging (high-resolution endoscopy, autofluorescence imaging and NBI) for colonic polyp characterization. Three studies from the same group show a poor diagnostic accuracy for NBI without magnifica‐ tion and autofluorescence with similar sensitivity but worse specificity [59,63,64]. Ignjatovic et al. [56] reported that NBI with magnification appeared to have the best accuracy, albeit modest and not adequate for in vivo diagnosis.

#### *2.2.5. NBI without optical magnification*

Most of the studies on prediction of histology using NBI have been carried out in Japan us‐ ing Olympus equipments with optical magnification (Lucera), a feature not included in high-resolution systems (Exera) available in the USA and in continental Europe. Most of the capillary pattern descriptions or classifications have been designed using optical magnifica‐ tion, therefore are not directly applicable to high-resolution examinations. That is also the case for the Kudo´s pit pattern classification.

The results of NBI without optical magnification in predicting histology are variable with authors showing an accuracy similar to that of optical magnification NBI and authors ob‐ taining worse results [56]. Again, different definitions for a vascular pattern typical of ade‐ noma (table 4) may account for these discrepancies. None of these classifications have been appropriately validated and its reproducibility in different clinical settings is unknown.

**Table 4.** Prediction of histology using NBI without magnification

sive invasion on the basis of thick and severely irregular vascular pattern was 100%. Kanao et al. [55] used a combination of capillary pattern and pit pattern and showed that lesions with irregular microvessels with variable sizes and distribution, and pit absence with avas‐

NBI has been compared with other image enhancing technologies, most frequently with chromoendoscopy. Overall, the diagnostic accuracy of NBI is better than that of convention‐ al colonoscopy and equivalent to that of chromoendoscopy (figure 3) [46,47,52], especially if

**Figure 3.** Invasive carcinoma in a depressed lesion observed with white light (a), NBI (b), and chromoendoscopy (c)

Four recent studies perform an evaluation of endoscopic trimodal imaging (high-resolution endoscopy, autofluorescence imaging and NBI) for colonic polyp characterization. Three studies from the same group show a poor diagnostic accuracy for NBI without magnifica‐ tion and autofluorescence with similar sensitivity but worse specificity [59,63,64]. Ignjatovic et al. [56] reported that NBI with magnification appeared to have the best accuracy, albeit

Most of the studies on prediction of histology using NBI have been carried out in Japan us‐ ing Olympus equipments with optical magnification (Lucera), a feature not included in high-resolution systems (Exera) available in the USA and in continental Europe. Most of the capillary pattern descriptions or classifications have been designed using optical magnifica‐ tion, therefore are not directly applicable to high-resolution examinations. That is also the

The results of NBI without optical magnification in predicting histology are variable with authors showing an accuracy similar to that of optical magnification NBI and authors ob‐ taining worse results [56]. Again, different definitions for a vascular pattern typical of ade‐ noma (table 4) may account for these discrepancies. None of these classifications have been appropriately validated and its reproducibility in different clinical settings is unknown.

cular areas harbored more often massive submucosal invasion.

*2.2.4. NBI compared with other diagnostic modalities*

184 Colonoscopy and Colorectal Cancer Screening - Future Directions

modest and not adequate for in vivo diagnosis.

case for the Kudo´s pit pattern classification.

*2.2.5. NBI without optical magnification*

vascular assessment rather than pit pattern is used [51].

The group of the Indiana University has very recently designed a simple classification for determination of polyp histology (NICE classification) and has validated it for its use by ex‐ perienced and non-experienced examinators (table 5) [70]. Further studies are needed to evaluate the reproducibility of this classification in real-time endoscopy.

#### *2.2.6. Prediction of histology of diminutive polyps*

Some authors have evaluated de diagnostic accuracy of NBI on diminutive polyps showing similar results to those on polyps of any size. In a study by Rex [67] the sensitivity of NBI in diagnosing adenomas was 92%, specificity 87%, PPV was 88%, NPV 91% and accuracy 89%. Grading the confidence on the endoscopic diagnosis in high and low, high confidence pre‐ dictions of adenomas were correct in 92% of polyps and in 91% of ≤ 5 mm polyps. The equivalent figures for hyperplastic prediction were 95%. The same group evaluated the per‐ formance of NBI in real time for distal colorectal polyps, and showed a sensitivity of 96%, a specificity of 99.4%, and NPV and PPV of 99.4% and 96% respectively [71]. The authors con‐ cluded that NBI is sufficiently accurate to allow distal hyperplastic polyps to be left in place without resection and small, distal adenomas to be discarded without pathologic assess‐ ment. In the study of Henry et al. [54] the sensitivity for predicting histology was 87%, spe‐ cificity was 93%, PPV was 89%, NPV was 91% and overall accuracy was 90%. Paggy et al. [72] found similar results both in the whole group of < 10 mm polyps and in diminutive pol‐ yps. Other authors have not showed as good results [56,73]. The most recent report using the NICE classification found an accuracy of 89%, sensitivity of 98% and a NPV of 95%. In conclusion, diagnostic accuracy of endoscopic prediction of histology of diminutive polyps seems equivalent to that of larger polyps, at least in expert hands.

**3. Conclusion**

be supported by Professional Societies.

Address all correspondence to<EMAIL_ADDRESS>
EndoscopyUnit. University Hospital La Fe.Valencia, Spain

to take this step forward.

Marco Bustamante-Balén\*

**Author details**

**References**

10-29.

138, 2177-90.

papers/DE/de050402.pdf.

New image-enhancing technologies may allow in vivo histological assessment of colorectal polyps, avoiding the need to pathological evaluation of all resected polyps. This would rep‐ resent substantial savings and a more direct planning of surveillance intervals [81]. Howev‐ er, there are several steps to achieve before the resect and discard strategy is widely implemented. First a more simple, reproducible and validated way of characterize colon le‐ sions is needed, especially in community practice. Learning the technique is also crucial be‐ cause when learning curve is achieved NBI performs significantly better [68]. Moreover, implementing PIVI guidelines [33] implies accepting a 10% rate of false negative when in vivo assessing histology of rectal polyps. Endoscopists may feel more comfortable with a much lower rate before leaving polyps behind. Finally, if in vivo histology is applied in dai‐ ly practice this represents a turning point in the management of colon polyps, which must

In vivo Optical Diagnosis of Polyp Histology: Can We Omit Pathological Examination of Diminutive Polyps?

http://dx.doi.org/10.5772/53205

187

In vivo histology seems here to stay, but we are still at the beginning of the way. Improve‐ ment in equipments and development of new technologies will help the medical community

[1] Siegel, R., Naishadham, D., & Jemal, A. (2012). Cancer Statistics . *CA Cancer J Clin*, 62,

[2] Ferlay, J., Autier, P., Boniol, M., Heanue, M., Colombet, M., & Boyle, P. (2007). Esti‐ mates of the cancer incidence and mortality in Europe in 2006. *Ann Oncol*, 18, 581-92.

[3] Gellad, Z. F., & Provenzale, D. (2010). Colorectal cancer: national and international perspective on the burden of the disease and public health impact. *Gastroenterology*,

[4] Oliva, J., Lobo, F., López-Bastida, J., Zozaya, N., & Romay, R. Pérdidas de productivi‐ dad laboral ocasionadas por los tumores en España. http://docubib.uc3m.es/working‐

**Table 5.** The NBI International colorectal endoscopic (NICE) classification

#### *2.2.7. Learning NBI. Does expertise matters?*

Most of the published studies have been performed by experts endoscopists, both in Japan and in Western countries. Reliable information about reproducibility of this results is lack‐ ing. Moreover, the overall accuracy in prediction of histology es markedly influenced by expertise in NBI interpretation, as has been shown in a study performed in a non academic setting in which sensitivity for high-confidence prediction was 77% and specificity 78% [73].  Fortunately, NBI interpretation of histology can be easily learned. Several studies have shown significant improvements in diagnostic accuracy and in interobserver agreement after following a computer-based training module [75] or a short teaching ses‐ sion [76].

#### **2.3. Fujinon intelligent color enhancement system (FICE) and i-Scan**

FICE also narrowes the bandwidth of light components using a computed spectral estima‐ tion technology that aritmetically processes the reflected photons to reconstitute virtual im‐ ages for a choice of different wavelenghts [77]. Therefore, it no depends on optical filters to modify the image. There are less studies using FICE or i-Scan than NBI but its accuracy seems broadly similar.

In the study by Pohl et al. [77] FICE (with set 4 activated) was used to identify the pit pattern and the vascular pattern intensity in a similar way to NBI. The sensitivity and specificity of FICE for the prediction of adenoma was 93.2% and 61.2%, figures similar to those of chro‐ moendoscopy. Parra et al. [78] showed that FICE performance in predicting histology was inferior to that of chromoendoscopy with magnification. Kim et al. [80] reported that FICE with magnification was better than without magnification especially for diminutive polyps [79]. Regarding i-Scan, a study compared this technology with NBI for histology prediction of diminutive polyps and showed a similar performance with good agreement between the two modalities (kappa index > 0.7).


Preface

Scientific and technological development has led to the formulation of tailor-made materials, which have given rise to materials with new structural and industrial applications. This book aims to analyze the synthesis, characterization, and applications of ceramic materials. First, an introduction to traditional and advanced ceramics is made, followed by an overview of material preparation techniques and various applications in recent years. Then, traditional ceramic materials as ideal candidates for absorbing wastes are studied, offering the possibility of obtaining new eco-efficient ceramic materials, such as concrete, while competitively approaching the concept of the circular economy. The following chapters focus on the study of different advanced ceramics. During the last decade, nanoceramics have received significant attention as candidate materials due to their ability to demonstrate improved and unique properties compared to conventional ceramics. The obtaining of ceramic nanopowders is studied by a new obtaining method called the dissolution method with advantages with respect to solvothermal, sol-gel, and coprecipitation methods. Also analyzed are plasma resistance and the characteristics of yttria ceramics in terms of calcination and three-step sintering compared to alumina and zirconia ceramics as well as the characteristics of hot-pressed pure yttria ceramics that are annealed in an oxidation atmosphere. Finally, a study of some equivalent circuit models most useful for impedance spectroscopic studies of electronic ceramics and their simulated immittance behavior is made.

### **Dolores Eliche-Quesada**

Department of Chemical, Environmental, and Materials Engineering, Higher Polytechnic School of Jaén, University of Jaen, Campus Las Lagunillas s/n, 23071 Jaén, Spain

#### **Luis Pérez-Villarejo**

Department of Chemical, Environmental, and Materials Engineering, Higher Polytechnic School of Linares, University of Jaen, Campus Científico-Tecnológico Cinturón Sur s/n, 23700 Jaén, Linares, Spain

#### **Pedro J. Sánchez-Soto**

Materials Science Institute of Sevilla (ICMS), Joint Center Spanish National Research Council (CSIC)-University of Sevilla, c/Américo Vespucio, 49, 41092 Sevilla, Spain

Chapter 1

Introductory Chapter: Ceramic

Characterization, Applications

Ceramic materials can be defined as inorganic materials constituted by the combination of metallic and nonmetallic elements whose properties depend on the way in which these elements are linked [1, 2]. Ceramic materials are the most versatile branch of materials. The origin of this versatility lies in the chemical nature of its bonds, since they are mainly constituted by strong ionic and covalent bonds in different proportions. The bonds determine a series of particular properties of ceramic materials among which are relatively high fusion temperatures, high modulus, high wear strength, poor thermal properties, high hardness and fragilities combined with tenacities, and low ductility. In addition to the lack of conduction electrons since they are combined forming chemical bonds, they are good electrical

Ceramic materials can be divided into two large groups: traditional ceramics and technical or advanced ceramics. Traditional ceramics can be defined as those that are based on silicates, among which are cement, clay products, and refractories. Traditional ceramics are produced in large volumes and constitute an important market. Traditional ceramic materials are made with raw materials from natural deposits such as clay materials. The second group, technical or advanced ceramics, is manufactured with artificial raw materials that have undergone an important chemical processing to achieve a high purity and an improvement of their physical characteristics. Therefore, they are manufactured with more advanced and sophisticated methods. Among them are carbides, nitrides, borides, pure oxides, and a

great variety of ceramics with magnetic, ferroelectric, piezoelectric, and superconducting applications, among others. These ceramics possess excellent mechanical properties under extreme conditions of tension, high wear strength or excellent electrical, magnetic, or optical properties, or exceptional strength to high temperatures and corrosive environments, showing high strength to chemical attack [3]. There is a third group that is glasses that, although considered ceramic, are studied separately because they differ from the first group in the order reached

The versatility mentioned above also allows ceramics to be used for a large number of end user and applications for the construction and building industry such as clay bricks and blocks, sanitary ware, and wall and floor tiles; in household

by their crystalline structures as glass-ceramics.

Dolores Eliche-Quesada, Luis Pérez-Villarejo and

Materials - Synthesis,

and Recycling

Pedro José Sánchez-Soto

1. Introduction

insulators.

1


Parkinsonism and Potential of Mucuna Beans

*Suresh S. Suryawanshi, Prajakta P. Kamble, Vishwas A. Bapat and Jyoti P. Jadhav*

### **Abstract**

Parkinson's is a neurodegenerative disease, which is common all over the world. Various aspect like damages of reactive oxygen species, excitotoxicity, mitochondrial dysfunction, and inflammation-facilitated cell damages are included in the etiology of disease. Good-balanced nutrition is an important part involved in the body health maintenance and reduction in the risk of chronic diseases. Genus *Mucuna* falls under family Fabaceae, containing high contents of L-DOPA (commonly used as an anti-Parkinson drug). Plant-based medicines are the superfluous source of polyphenols, flavonoids, carotenoids, antioxidants (ROS and RNS), terpenoids, isoflavonoids, and other biologically active phytochemicals. All these molecules have health beneficial effects with superlative pharmaceutical values. The existing chapter summaries to determine the influence of different nutritional, anti-nutritional, and medicinal potential of the *Mucuna* species present in India and its significance in the management of Parkinson's disease (Shaking Palsy) as well as other medicinal values. It also covers various treatment models used in studying the Parkinson's disease like *Drosophila melanogaster*, zebrafish, mice, rat, and humans. This chapter also focuses light on the neurosurgical treatments used in the treatment of Parkinson's disease. This study concluded that the use of *Mucuna* seeds for the treatment of Parkinson's disease is the best choice besides chemical drugs and other therapies.

**Keywords:** Kampavata, L-DOPA, *Mucuna*, neuroprotective, experimental models, neurosurgical remedy

## **1. Introduction**

Research in plant-based medicine is gaining much more attention due to its lack of side effects, its large availability, and its multiple medicinal applications. In the past few years, this has also increased people's awareness toward functional food, thus enhancing the consumption rate of legumes enormously [1]. The attention toward *Mucuna* improved colossally after 1937 when it was initially revealed that a huge quantity of levodopa is present in it. Genus *Mucuna,* which is familiar by different names (like: velvet beans, sea beans, cowitch, buffalo beans, cowhage, atmagupta, kapikachu, and dopa bean), is one of the conventional medicine performing crucial roles in both health and disease management. *Mucuna* is an excellent source of proteins, starch, micronutrients, dietary fiber, and bioactive compounds (L-DOPA), which play a great role in the traditional as well as modern medicine all

over the world against Parkinson's disease. The genus *Mucuna* belongs to the family *Leguminosae* distributed throughout the tropical and subtropical regions of various countries of the world comprising hundreds of species [2]*.* Recently, Pulikkalpura et al. [3] and Patil et al. [4, 5] studied the occurrence and biochemical activities of various *Mucuna* species in India.

Plant-based remedies are most beneficial remedies, having a cumulative effect of phytochemical and other bioactive components obtained from plants. *Mucuna* has various actions like antioxidant activity, anti-inflammatory activity, wound-healing activity, and activity against snake bite. Along with all this, *Mucuna* is also rich in nutritional and anti-nutritional compounds (rich in minerals) [6]. *Mucuna* is also well known for nematicidic effects and also possesses notable allelopathic activity, which was reported by Gliessman et al. [7]. In countries like Guatemala and Mexico, it is used as a coffee substitute. Along with that, in some countries (lower hills of the eastern country and Himalayas), it is commonly consumed as vegetable beans after frying and boiling. *Mucuna* seed powder has been used in active management of Parkinson's disease in several countries due to its L-DOPA content.

In early health care system of India, Parkinson's disease (PD) is known as "Kampavata", which is a common neurological disorder related to neuromelanin containing nigrostriatal dopaminergic neuronal loss. Kampa means tremor and vata means lack of muscular movement. It was found via door-to-door survey in Bangalore (Karnataka, India) that 76 per 100, 000 (age adjusted) and 33 per 100,000 (crude prevalence) people suffered from Parkinsonism [8]. Out of that, 5–10% of individuals having PD belong to families with history of genetic disorders [9, 10]. The disease commonly occurs in the age group of 60–80. A survey on Parsi community in Mumbai shows that they were diminutively stable to PD [8]. Diagnosis of disease is sometimes difficult by clinical method, which involves analysis by considering large number of motor and non-motor symptoms in PD patients. PD is caused due to decrease in dopaminergic neurons in the substantia nigra pars compacta (SNpc) part of the brain, which leads to motor symptoms including rigidity, bradykinesia, tremor, and development of some non-motor symptoms in later stages of the disease. Although there is significant number of improvements in the medicinal and surgical actions against PD, scientists have not yet identified definite targets for disease management. According to research by Ramanan and Saykin, neurodegeneration is divided in to four main levels out of which aggregation and accumulation of abnormal or misfolded mutated proteins is crucial [11]. Some reports examine that oxidative stress (OS) and neuroinflammation (NIF) are the main reasons of neurodegenerative disease. Thus, to tackle these neurodegenerative disorders, researchers have diverted their attention toward finding oxidative stress enzymes and pathogenesis of PD. Abraham et al. studied 115 cases of PD and concluded that catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (G-Px), and glucose-6-phosphate dehydrogenase (G6PD) levels are present in greater quantities in PD patients as compared to the control patients [11]. Various oxidative stress enzymes, pro-inflammatory cytokines, proteinase, reactive oxygen intermediates, and complement proteins are secreted by the immune cells against the neuronal cell damage response, which leads to inflammation. Along with mitochondrial dysfunction, altered proteolysis, oxidative damage of cells and Lewy bodies' formation are some of the symptoms of Parkinson's disease.

There are various strategies for the management for PD but there is no complete cure for this disease. The only management of the lowered dopamine levels is to control various metabolic inhibitions and enhancement pathways, preventing degeneration of neurons and other non-dopaminergic (surgelogical) treatment. L-DOPA (L-3,4 dihydroxy phenylalanine) is a non-protein amino acid used in the

**137**

**Figure 1.**

*Parkinsonism and Potential of Mucuna Beans DOI: http://dx.doi.org/10.5772/intechopen.92855*

and other treatments used in treating Parkinson's disease.

**2. Treatment strategies of Parkinson's disease**

*Synthesis pathway of L-DOPA, dopamine and further metabolites.*

**2.1 Neuroprotective potential of** *Mucuna*

treatment of Parkinson's disease. It acts as precursor of dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). It is synthesized by plants, animals, and microbes (bacterial and fungus) and has a different role in each source. Chemical synthesis of L-DOPA is easy but the purification of L and D forms is slightly complicated and expensive. Synthetic L-DOPA is considered as anti-nutritional factor and its consumption causes abdominal distention, vomiting, dyskinesia, nausea, etc. This happens when L-DOPA is converted to dopamine in the peripheral nervous system by enzyme dopa decarboxylase. Whereas, L-dopa is also used as the treatment against infertility recovering the spermatogenic harm to some extent. Numerous other secondary metabolites produced by plants like flavonoids and phenolics illustrate strong anti-inflammatory and antioxidant potentials, which have a significant role in the management of health and disease of human beings. The current book chapter is focused on the use of plant source of L-DOPA and neuroprotective potential of magical dopa beans and their special prominence in Parkinson's disease treatment. Along with this we have also focused on the models

Parkinson's disease (PD) was initially discovered by Dr. James Parkinson in 1817; it is a chronic neurological disorder triggered by a progressive loss of dopaminergic neurons present in the nigrostriatal part of the brain and found to be common in U.S [12]. In 1970, only few effective drugs were available for treatment of the PD but there is no such therapy yet that completely treats PD. Only thing we can do is to stop the progression of Parkinson's disease or delay the of PD by replacement of dopaminergic neuron or by mimicking the neuron by using substituent. Management of PD is mainly divided into two categories: first involves improving symptomatic treatment of motor and non-motor types of symptoms and second will be addressing potential causes of PD. Firstly in 1978 Vaidya et al., published the report that PD can be treated by *Mucuna* extract, a natural source of levodopa having better activity than the synthetic version of levodopa drug [13]. Similar studies were reported in 1990 and 1994 by Kempster et al. and Rabey et al. [14, 15]. L-DOPA is a precursor of dopamine (**Figure 1**), norepinephrine (noradrenaline),

*Parkinsonism and Potential of Mucuna Beans DOI: http://dx.doi.org/10.5772/intechopen.92855*

*Bioethics in Medicine and Society*

various *Mucuna* species in India.

over the world against Parkinson's disease. The genus *Mucuna* belongs to the family *Leguminosae* distributed throughout the tropical and subtropical regions of various countries of the world comprising hundreds of species [2]*.* Recently, Pulikkalpura et al. [3] and Patil et al. [4, 5] studied the occurrence and biochemical activities of

Plant-based remedies are most beneficial remedies, having a cumulative effect of phytochemical and other bioactive components obtained from plants. *Mucuna* has various actions like antioxidant activity, anti-inflammatory activity, wound-healing activity, and activity against snake bite. Along with all this, *Mucuna* is also rich in nutritional and anti-nutritional compounds (rich in minerals) [6]. *Mucuna* is also well known for nematicidic effects and also possesses notable allelopathic activity, which was reported by Gliessman et al. [7]. In countries like Guatemala and Mexico, it is used as a coffee substitute. Along with that, in some countries (lower hills of the eastern country and Himalayas), it is commonly consumed as vegetable beans after frying and boiling. *Mucuna* seed powder has been used in active management of

Parkinson's disease in several countries due to its L-DOPA content.

In early health care system of India, Parkinson's disease (PD) is known as "Kampavata", which is a common neurological disorder related to neuromelanin containing nigrostriatal dopaminergic neuronal loss. Kampa means tremor and vata means lack of muscular movement. It was found via door-to-door survey in Bangalore (Karnataka, India) that 76 per 100, 000 (age adjusted) and 33 per 100,000 (crude prevalence) people suffered from Parkinsonism [8]. Out of that, 5–10% of individuals having PD belong to families with history of genetic disorders [9, 10]. The disease commonly occurs in the age group of 60–80. A survey on Parsi community in Mumbai shows that they were diminutively stable to PD [8]. Diagnosis of disease is sometimes difficult by clinical method, which involves analysis by considering large number of motor and non-motor symptoms in PD patients. PD is caused due to decrease in dopaminergic neurons in the substantia nigra pars compacta (SNpc) part of the brain, which leads to motor symptoms including rigidity, bradykinesia, tremor, and development of some non-motor symptoms in later stages of the disease. Although there is significant number of improvements in the medicinal and surgical actions against PD, scientists have not yet identified definite targets for disease management. According to research by Ramanan and Saykin, neurodegeneration is divided in to four main levels out of which aggregation and accumulation of abnormal or misfolded mutated proteins is crucial [11]. Some reports examine that oxidative stress (OS) and neuroinflammation (NIF) are the main reasons of neurodegenerative disease. Thus, to tackle these neurodegenerative disorders, researchers have diverted their attention toward finding oxidative stress enzymes and pathogenesis of PD. Abraham et al. studied 115 cases of PD and concluded that catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (G-Px), and glucose-6-phosphate dehydrogenase (G6PD) levels are present in greater quantities in PD patients as compared to the control patients [11]. Various oxidative stress enzymes, pro-inflammatory cytokines, proteinase, reactive oxygen intermediates, and complement proteins are secreted by the immune cells against the neuronal cell damage response, which leads to inflammation. Along with mitochondrial dysfunction, altered proteolysis, oxidative damage of cells and Lewy bodies' formation are some of the symptoms of

There are various strategies for the management for PD but there is no complete cure for this disease. The only management of the lowered dopamine levels is to control various metabolic inhibitions and enhancement pathways, preventing degeneration of neurons and other non-dopaminergic (surgelogical) treatment. L-DOPA (L-3,4 dihydroxy phenylalanine) is a non-protein amino acid used in the

**136**

Parkinson's disease.

treatment of Parkinson's disease. It acts as precursor of dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). It is synthesized by plants, animals, and microbes (bacterial and fungus) and has a different role in each source. Chemical synthesis of L-DOPA is easy but the purification of L and D forms is slightly complicated and expensive. Synthetic L-DOPA is considered as anti-nutritional factor and its consumption causes abdominal distention, vomiting, dyskinesia, nausea, etc. This happens when L-DOPA is converted to dopamine in the peripheral nervous system by enzyme dopa decarboxylase. Whereas, L-dopa is also used as the treatment against infertility recovering the spermatogenic harm to some extent. Numerous other secondary metabolites produced by plants like flavonoids and phenolics illustrate strong anti-inflammatory and antioxidant potentials, which have a significant role in the management of health and disease of human beings.

The current book chapter is focused on the use of plant source of L-DOPA and neuroprotective potential of magical dopa beans and their special prominence in Parkinson's disease treatment. Along with this we have also focused on the models and other treatments used in treating Parkinson's disease.


**8. Conclusion**

Indian spirituality and meditation are established knowledge tools and expected to be incorporated into the Indian education system in order to strengthen and popularize it. These are unique in the world, so they should be practice and taught in schools from kindergarten. It provides lot of opportunities for students' personality development along with development of fundamental knowledge and skills. The present education system attempts to achieve significant success in the formation of personality, the development of personality, and the contribution of knowledge to all aspects of learning, social well-being and material prosperity and has been emphasized in National Education Policy 2020 (NEP 2020). The current Indian curriculum development system must develop a special form of education in order to establish harmony between materialism and spiritualism with humans to achieve greater perfection.


**About the Editors**

**Giovanni Pau** (Professor) received a B.S. in telematic engineering from the University of Catania, Italy; a M.S. (cum laude) in telematic engineering; and a Ph.D. from the Kore University of Enna, Italy. He is currently an Associate Professor with the Faculty of Engineering and Architecture, Kore University of Enna. He is the author or coauthor of more than 65 refereed articles published in journals and conference proceedings. His research interests include wireless sensor networks, fuzzy logic controllers, intelligent transportation systems, green communications, and network security. He has been involved in the organization of several international conferences as the session co-chair and technical program committee member. He serves as a leading guest editor for Special Issues of several international journals. He is an Editorial Board Member and an Associate Editor of several journals such as IEEE ACCESS, Wireless Networks (Springer), EURASIP *Journal on Wireless Communications and Networking* (Springer), *Wireless Communications and Mobile Computing* (Hindawi), and *Future Internet* (MDPI).

**Hsing-Chung Chen** (Professor) received a Ph.D. in Electronic Engineering from National Chung Cheng University, Taiwan, in 2007. From February 2008 to July 2018, he was sn Assistant Professor and Associate Professor in the Department of Computer Science and Information Engineering at Asia University, Taiwan. Since August 2018 until July 2019, he was a Full Professor in the Department of Computer Science and Information Engineering at Asia University, Taiwan. From August 2019–present, he has been a Distinguished Full Professor with the Department of Computer Science and Information Engineering, Asia University, Taiwan. From August 2019–July 2020, he was Chairman with the Department of Computer Science and Information Engineering, Asia University, Taiwan. Since May 2014–present, he has also been the Research Consultant of Dept. of Medical Research, China Medical University Hospital, China Medical University Taichung, Taiwan. In addition, since Feb 2017, he has been the Permanent Council Member of Taiwan Domain Names Association (Taiwan DNA), Taiwan. He was also the Program Committee Chair of APNIC44 (September 2017) organized by Asia-Pacific Network Information Centre (APNIC). He has been awarded Best Paper Awards by BWCCA2018, MobiSec2017 and BWCCA2016, individually. He was awarded the Best Journal Paper Award by Association Algorithm & Computation Theory (AACT). Currently, his research interests include information and communication security, cyberspace security, blockchain network security, internet of things, application engineering and security, mobile and wireless networks protocols, medical and bio-information signal image processing, artificial intelligence and soft computing, and applied cryptography.

**Fang-Yie Leu** (Distinguished Professor) received his B.S., M.S., and Ph.D. degrees all from National Taiwan University of Science and Technology, Taiwan, in 1983, 1986, and 1991, respectively. His research interests include wireless communication, network security, grid applications, and sensor networks. He is currently a distinguished professor with the Computer Science Department, and the chairperson of the Big Data Program, Tunghai University, Taiwan. He also acts as an Editorial Board Member of at least 7 journals and serves as the TPC member of at least 10 international conferences. Prof. Leu now organizes MCNCS and CWECS international workshops. He is an IEEE member and was also a visiting scholar of Pittsburg University.

**Ilsun You** (Professor) received M.S. and Ph.D. degrees in computer science from Dankook University, Seoul, Korea, in 1997 and 2002, respectively. He received a second Ph.D. from Kyushu University, Japan, in 2012. From 1997 to 2004, he was at THINmultimedia Inc., Internet Security Co., Ltd. and Hanjo Engineering Co., Ltd. as a research engineer. Now, he is a full professor with the Department of Information Security Engineering, Soonchunhyang University. Prof. You is the EiC of the *Journal of Wireless Mobile Networks, Ubiquitous Computing, and Dependable Applications* (JoWUA) and *Journal of Internet Services and Information Security* (JISIS). He is on the Editorial Board for *Information Sciences* (INS), *Journal of Network and Computer Applications* (JNCA), IEEE *Access, Intelligent Automation & Soft Computing* (AutoSoft), *International Journal of Ad Hoc and Ubiquitous Computing* (IJAHUC), *Computing and Informatics* (CAI), and *Journal of High Speed Networks* (JHSN). He has especially focused on 4/5G security, security for wireless networks and mobile internet, IoT security, and so forth, publishing more than 180 papers in these areas. He is a Fellow of the IET and a Senior member of the IEEE.


**7. Conclusion**

580 Risk Management – Current Issues and Challenges

A system was developed to ingest output data from the Predictive Atmospheric-Ocean Model for Australia (POAMA) GCM [17]. A user-facing component was developed, based on a rich web-based interface that provides a one-stop shop for access to dynamical modelbased outlooks. The purpose of the tool is to provide a specialised point of access to CGCM based seasonal outlooks for the national meteorological services of Pacific Island countries.

This project was supported by the Pacific Adaptation Strategy Assistance Program (PASAP), a component of the International Climate Change Adaptation Initiative - an Australian Government Initiative of \$328 million over five years, 2008-2013 to assist with high priority climate adaptation needs in vulnerable countries in the Asia-Pacific region. As part of this program, the Australian Bureau of Meteorology lead a project to strengthen climate prediction capacities in the national meteorological and hydrological services of Pacific Island countries, including countries both north and south of the equator: Papua New Guinea, Tuvalu, Kiribati, Fiji, Marshall Islands, Federated States of Micronesia, Palau, Nauru, Cook Islands, Samoa, Tonga, Niue, Solomon Islands, Vanuatu and East Timor. A key element of this work was the development of a web-based application providing access to dynamical model-based seasonal outlooks. As previously described, one means to reduce vulnerability to climate change is by improve preparedness to anomalous climatic events.

Graphical displays of seasonal forecasts of broad-scale, point and climate driver forecasts are generated with an example shown in Figure 9. The web application displays the contextual information provided as meta-data by the data service layer, consumes the outputs of web services that produce figures and tables. It displays model-based outlooks as overlays on dynamical maps using geospatial web services. Access is given not just to application graphics but also to outlook data. User-friendly options for data extraction from

An agile, iterative approach to the development of the web portal user interface (UI) included testing of early development versions of the portal with users at a project workshop, and in a series of country visits. These sessions validated the overall UI design

While much work went into the web front end, an equal amount of work was spent ensuring that the forecast generation layer is decoupled from this specific client. The access to the data provided by the data service layer allows for the future design of web clients that perform computational value adding using processing services, for example the ingestion

The integration of data into a dynamical mapping tool provides opportunities for data mash-up in which data from different sources is displayed in composite. The provision of geospatial information in such a way that data from multiple sources can be integrated opens the way for new and interesting applications. For example, one potential future application for seasonal forecasting might be the display of agricultural or fishery yield data

the web portal are provided to support users of the range of tools from Excel to R.

and subsequent combination and calibration of multiple selected models.

and provided valuable feedback for improvements.

overlaid with outlook reliability data.

From the physical basis to the complexities of applications to specific industries and decisions it is clear that seasonal prediction is a large-scale enterprise requiring coordinated work across a range of scientific and technological disciplines. Steady improvements in GCM resolution and physics, coupled with ever increasing understanding of the physical mechanisms of predictability, will ensure that seasonal predictions become an important component of adaptation to a changing and more variable climate.


*3.2. Increased Mitochondrial ROS Levels in J82 Cells Treated with Scabertopin*

We detected the cells treated with scabertopin for 24 and 48 h using a DCF fluorescent probe and found that scabertopin treatment could significantly increase the content of intracellular ROS (Figure 2A). To determine the mechanism of ROS production caused by scabertopin, we used a JC-1 assay to observe the changes of ΔΨ in the J82 cells treated with scabertopin. The results showed that ΔΨ decreased (red fluorescence decreased while green fluorescence increased) after scabertopin treatment (Figure 2C,D). In conclusion, the ΔΨ of the scabertopin treatment group decreased significantly compared to the control group.

The ROS in mitochondria are usually in the form of hydrogen peroxide (H2O2) and superoxide anions (O2 −). However, H2O2 is hardly able to escape through the mitochondrial membrane and be detected in the cytoplasm, and, thus, superoxide anion produced in the mitochondria and transported to the cytoplasm has become a key signaling factor for mitochondrial ROS [31]. Therefore, we used a DHE fluorescent probe to detect the content of superoxide anion in the cells treated with scabertopin. The results showed that the level of superoxide anion in the scabertopin treatment group was significantly higher than that in the control group (Figure 2B).

**Figure 2.** Increased mitochondrial ROS and reduced mitochondrial membrane potential in J82 cells treated with scabertopin. (**A**) Scabertopin induces ROS production in a dose- and time-dependent manner. (**B**) The DHE probe assay shows that superoxide anion is positively correlated with the scabertopin dose. (**C**) The JC-1 assay shows that, after 24 h treatment, scabertopin decreases the mitochondrial membrane potential in J82 cells in a dose-dependent manner. (**C**) The JC-1 assay shows that NAC treatment can restore the mitochondrial membrane potential reduced by 24 h treatment of scabertopin to some extent. (**D**) The DHE probe assay shows that superoxide anion is positively correlated with the scabertopin dose. (**E**) A 24 h treatment with 10 μM of scabertopin is efficient in depleting GSH through a dose-dependent mechanism in J82 cells, which can be reversed with NAC treatment. A total of 5 μM of NAC was used in the experiments. Data represent the mean ± standard error of mean (s.e.m.) of the three independent experiments. \*\* *p* < 0.01, \*\*\* *p* < 0.001, ns: no significance vs. 0 μM scabertopin-treated group. NAC: *N*-acetylcysteine; SA: scabertopin.

In addition, GSH is an important antioxidant in cells, and we also detected the changes in intracellular GSH after scabertopin treatment (Figure 2E). The results showed that scabertopin treatment could deplete GSH, which is one of the reasons for the accumulation of intracellular ROS, and the efficacy of scabertopin depleting GSH could be blocked by NAC (Figure 2E).


*4.2. Leaf* δ*15N Values Changed with Leaf Age and Tree Age*

Leaf nitrogen isotope compositions were determined by the isotope ratio of the external nitrogen source and physiological mechanisms within the plant. However, the intra-plant variation in isotope composition was caused by multiple assimilation events, organ-specific losses of nitrogen as well as resorption and reallocation of nitrogen [12]. In our work, 15N of current year leaves were more enriched compared to other mature leaves—a pattern completely similar to stable carbon isotope compositions. Meanwhile, the result of Figure 5 indicated that these ratios shift similarly to leaf age. Nitrogen as a key nutrient to build up the photosynthetic apparatus was translocated either from the roots, storage organs or mature leaves to growing leaves [13]. Therefore, there may be variation in δ15N of leaves throughout the plant depending on sink/source activity and the timing and source of remobilized and assimilated organic nitrogen [34,35]. Nitrogen remobilization was important for perennial plant survival. During growth, there was significant variation in primary N-containing compounds being remobilized in the plant [34]. Masclaux-Daubresse et al. [36] reported that N-containing compounds (like proteins, chlorophyll, etc.) could be degraded during leaf senescence and then nitrogen may be remobilized from senescing leaves to expanding leaves at the vegetative stage. For example, 15N-enriched glutamine was observed as the primary transport form of organic nitrogen, which would be remobilized to developing sink leaves (receiving enriched 15N-glutamine) from a source leaf (exporting enriched 15N-glutamine) [34]. Consequently, an enrichment of 15N in new leaves was expected. In addition, leaf proteins and in particular photosynthetic proteins of plastids were extensively degraded during senescence, providing an enormous source of nitrogen that plants could tap into to supplement the nutrition of growing organs such as new leaves and seeds [36]. Moreover, juvenile trees (<50 years old) were 15N depleted compared to middle-aged trees (50–100 years old) at each leaf age level except for 1-year-old leaves in this study. This was likely attributed to the various allocated proportions of the structural, functional and storage components within the plant bodies to meet the plant's nutrient demands [37]. In addition, there was a significant difference in water potential, stomatal conductance, photosynthetic rate, and water-use efficiency between juvenile trees and other aged trees [37].


*2.4. Melt Flow Rate (MFR)*

In order to evaluate the melt fluidity variation caused by the addition of HSP, the melt flow rate (MFR) were measured on the biocomposites pellets by a CEAST Melt Flow Tester M20 (Instron, Canton, MA, USA) equipped with an encoder. The standard ISO1133D method was used: the sample was preheated without any weight for 30 s at 190 ◦C and then a weight of 2.16 kg was applied. The molten material quantity that flows for 30 s was then weighted and the MFR calculated. At least three measurements for each composition were carried out and the mean MFR value reported. Before the test, the materials were kept in a ventilated oven at 60 ◦C to avoid the pellets water uptake.


**10. Conclusions**

Motivational ability, planning, behavior modulation, ability to complete an action program, identification of functional strategies to achieve the goal, problem solving, flexibility, monitoring and self-assessment of behavior in relation to results, change of task, or behavior in the light of emerging information may be all impaired by nocturnal intermittent hypoxia also during the developmental age. The final effects of this impairment may be identified in such clinical condition mimicking other neurobehavioral symptoms, such as ADHD [34], while learning problems may be sustained by OSAS [91, 92], or in Fragile X syndrome [93], in epilepsy [94], and in EEG abnormalities [95], suggesting that the sleep screening may be considered as mandatory in neurodevelopmental disorders.

*Updates in Sleep Neurology and Obstructive Sleep Apnea*

interrelated. It is precisely the transversal nature and the structural complexity that characterizes them, associated with their slow development process, to explain why multiple neuropsychiatric disorders of the developmental age (pervasive developmental disorders, behavioral disorders, speech disorders, learning disorders, and disorders of the nonverbal area) present, with varying degrees of symptomatic severity, a common deficit for executive functioning. There are also motivated situations in which a deficiency of theirs manifests itself with clinical signs and symptoms that are often nuanced, nonspecific, and not immediately diagnostic (instability of behavior and emotionality, distractibility, difficulty in moving from one activity to another, and atypia communication). To this lively theoretical debate on what and what the EFs are, a new theoretical contribution has recently been added linked to the different types of cognitive and behavioral deficits that have emerged from injuries to the different areas of the prefrontal cortex, which has

allowed a further classification in hot and cold executive functions [63].

neuropsychological tests used in clinical practice (DLPFC) [66].

closely related and combined in different situations of daily life.

ally, all mental activities [63].

ADHD [72], and OSAS [73].

disorder [77].

The "hot" executive processes involve the emotional-emotional sphere and are associated with the activity of the ventromedial prefrontal cortex (VMPFC); the "cold" executive ones concern cognitive and nonemotional processing and are associated with the activity of the dorsolateral prefrontal cortex and can be measured by

The "hot" executive functions recall phenomena such as empathy, the theory of the mind, emotional, and affective regulation, which coordinate the cognitive with the emotional sphere in order to adequately address the primary impulses with socially acceptable strategies. The "cold" executive functions intervene in cognitive, abstract, and decontextualized tasks (problem solving, abstraction, planning, working memory, and elaboration of strategies). Despite this distinction, they are

In summary, the EFs are a particular set of cognitive operations activated in pursuit of objectives, responsible for planning, the ability to set goals, to classify, to know how to execute an order, to control and monitor one's behavior, to know how to order a series of activities in order to achieve a goal, and to manage, more gener-

These functions are modified in some pathological conditions such as posterior cranial fossa neoplasms [67], localized posttraumatic lesions to the frontal lobe [68], neurodegenerative syndromes (i.e. Parkinson's disease and Alzheimer's disease) [69, 70], cerebrovascular malformations (i.e. Moya-Moya syndrome) [71],

The close relationship between cognitive functions has long been known and sleep, with particular reference to disorders respirators for which it has been widely demonstrated in the developmental age the association with learning disorders and more generally with alterations of the cognitive performance [74] that appears in such subjects dominated by slowness in concept development [75, 76] which however do not seem to be related to degree of severity of the respiratory

Several studies have focused on the role of the frontal lobes as possible relay zones between the OSAS and the cognitive alterations [78, 79]; however, studies conducted on executive functions of subjects with OSAS have pay attention exclusively to adult-

In this context, the close interconnection between OSAS and alteration specifications charged to executive functions. Furthermore, as reported in other studies, the modified card sorting test (MCST) is related especially to changes in blood flow for the frontal and hippocampal regions [80]. These data reflect the conclusions of recent neuroimaging studies on subjects suffering from OSAS, which would present a level reduction of the gray substance of the fronto parietal regions and

hood [79], leaving aside the impact of this disease in the developmental age.

**164**


**Author details**

Anthony Tibaingana1,2\*, Godswill Makombe2 and Tumo Kele3

1 Department of Marketing and Management, School of Business, Makerere University College of Business and Management Sciences, Kampala, Uganda

2 The University of Pretoria, Gordon Institute of Business Science, Johannesburg, South Africa

3 Tshwane School for Business and Society, Tshwane University of Technology, Pretoria, South Africa

\*Address all correspondence to<EMAIL_ADDRESS>
© 2022 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.

*Smallholder Maize Farmers Need Better Storage for Food Security: An Exploratory Study… DOI: http://dx.doi.org/10.5772/intechopen.109172*


**1. Introduction**

196 Lipoproteins – Role in Health and Diseases

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Coll Cardiol 2008;51:49-55.

[37] Kotseva K, Wood D, De Backer G, De Bacquer D, Pyörälä K, Keil U et al. EUROASPIRE III: a survey on the lifestyle, risk factors and use of cardioprotective drug therapies in coronary patients from 22 European countries. Eur J Cardiovasc Prev Rehabil

[38] MONICA monograph: World's largest study of heart disease, stroke, risk factors, and population trends 1979-2002. Tundstall-Pendoe H edition. WHO, Geneva, 2003. [39] Davey-Smith G, Song F, Sheldon TA. Cholesterol lowering and mortality: the

[40] Roe MT,Ou FS, Alexander KP, Newby LK, Foody JM, Gibler WB, Boden WE et al. Patterns and prognostic implications of low high-density lipoprotein levels in patients with non-ST-segment elevation Acute coronary syndromes. Eur Heart

[41] deGoma EM, Leeper NJ, Heidenreich PA. Clinical significance of high-density lipoprotein cholesterol in patients with low low-density lipoprotein cholesterol. J Am

[42] Lehto S, Palomaki P, Miettinen H et al. Serum cholesterol and high density lipoprotein cholesterol distribution in patients with acute myocardial infarction and in the general population of Kuopio province, eastern Finland. J Intern Med 1993;233(2):179-185.

importance of considering initial level of risk. Br Med J 1993;306:1367-1373.

### **1.1. What are lipids?**

Lipids consists of a broad group of naturally occurring molecules that include fats, waxes, sterols including cholesterol, fat-soluble vitamins (such as vitamins A, D, E, and K), monoglycerides, diglycerides, triglycerides, phospholipids, and others. Lipids were previously known as sources of energy storage and the building blocks for cell membrane. Lipids are now known to play several key roles in intracellular signalling, membrane trafficking, hormonal regulation, blood clotting (Muller-Roeber and Pical, 2002; Vance and Vance, 2002; Fahy *et al.*, 2009). All lipids may be defined as hydrophobic or amphiphilic small molecules. The amphiphilic nature of some lipids allows them to form structures such as vesicles, liposomes, or membranes in an aqueous environment. Biological lipids originate entirely or in part from two distinct types of biochemical subunits, which are ketoacyl and isoprene groups (Fahy *et al.*, 2009).

Lipids typically do not travel alone in the blood. Instead, it binds to a protein that transports it to its destination in the body. The complex formed by the binding of lipid to protein i.e. lipoprotein, makes lipids water soluble, which enables its transportation in blood. The lipoprotein particle is composed of an outer shell of phospholipids, which renders the particle soluble in water; a core of fats called lipid, including cholesterol and a surface apoprotein (apolipoprotein). Ideally, the lipoprotein aggregates should be described in terms of the different protein components (apolipoprotein) because this determines the overall structures and metabolism of the lipoprotein, and the interactions with receptor molecules in liver and peripheral tissues. The apolipoprotein molecule enables tissues to recognize and take up the lipoprotein particle. However, lipoproteins are classified based on their characteristic density on ultracentrifugation, which has been used to segregate the different lipoprotein classes. Lipoproteins are broadly classified as high density lipoprotein (HDL), low density lipoprotein (LDL), intermediate density lipoprotein (IDL), very low density lipoprotein (VLDL) and chylomicrons (CM). Each of these particles perform

© 2012 Saba and Oridupa, licensee InTech. This is an open access chapter 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. © 2012 The Author(s). Licensee InTech. 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.

different functions and can be detrimental (VLDL, IDL, LDL) or beneficial (HDL) to the cardiovascular system.

**Figure 1.** Structure of Lipoprotein available from http://www.campbell.edu

\*Most of the remaining materials comprise the various apolipoproteins

**Table 1.** Physical properties and lipid compositions of lipoprotein classes

#### **1.2. Role of cholesterol in membrane dynamics**

It is relevant to establish the important of cholesterol in the body to be able to relate the various metabolic events associated with cholesterol and its homeostasis. Mammalian cell membranes contain varying proportions of cholesterol depending on organelle and cell type. These levels are tightly controlled by lipid transfer, through both vesicular and protein-bound pathways. With its rigid sterol backbone, cholesterol preferentially locates among saturated membrane lipids that have straight, elongated hydrocarbon chains rather than among kinked, unsaturated species. The presence of cholesterol in the membrane increases lateral ordering of lipids, reducing permeability and fluidity and potentially restricting diffusion of membrane proteins. Its distribution is not uniform within a membrane: regions of high cholesterol and corresponding low fluidity are termed lipid rafts. These areas act as platforms for the assembly of signalling complexes within the membrane and have been implicated in the development of numerous disease processes, notably arteriosclerosis and cancer (Di Vizio *et al.*, 2008; Ikonen, 2008).

#### **2. Cardiovascular disease and risk factors**

198 Lipoproteins – Role in Health and Diseases

cardiovascular system.

different functions and can be detrimental (VLDL, IDL, LDL) or beneficial (HDL) to the

**Figure 1.** Structure of Lipoprotein available from http://www.campbell.edu

\*Most of the remaining materials comprise the various apolipoproteins

**1.2. Role of cholesterol in membrane dynamics**

**Table 1.** Physical properties and lipid compositions of lipoprotein classes

 CM VLDL IDL HDL Density (g/ml) < 0.94 0.94 – 1.006 1.006 – 1.063 1.063 -1.210 Diameter (Á) 6000 - 2000 600 250 70-120 Total lipid (wt %) \* 99 91 80 44 Triacylglycerols 85 55 10 6 Cholesterol esters 3 18 50 40 Cholesterol 2 7 11 7 Phospholipids 8 20 29 46

It is relevant to establish the important of cholesterol in the body to be able to relate the various metabolic events associated with cholesterol and its homeostasis. Mammalian cell membranes contain varying proportions of cholesterol depending on organelle and cell type. These levels are tightly controlled by lipid transfer, through both vesicular and protein-bound pathways. With its rigid sterol backbone, cholesterol preferentially locates Elevated plasma levels of low density lipoprotein (LDL) and low levels of high density lipoprotein (HDL) poses a major risk of development of cardiovascular diseases (Grundy *et al.*, 1999). A dietary intake of saturated fat and a sedentary lifestyle has been associated with about 31% of coronary heart disease and 11% of stroke in humans. According to the Framingham Heart Study and other studies (Wilson *et al.*, 1998), the major and independent risk factors for coronary heart disease (CHD) are cigarette smoking of any amount, elevated blood pressure, elevated serum total cholesterol and low-density lipoprotein cholesterol (LDL-C), low serum high-density lipoprotein cholesterol (HDL-C), diabetes mellitus, and advancing age. More recently, a review by Patrick and Uzick (2001) documented new risk factors for CHD which included levels of circulating homocysteine, fibrinogen, C-reactive protein (CRP), endogenous tissue plasminogen-activator, plasminogen-activator inhibitor type I, lipoprotein(a), factor VII and certain infections such as *Chlamydia pneumonia*. These studies showed that the total risk of an individual is the summation of all major risk factors.

Other factors contributing to the total risk for CHD are categorized as conditional risk factors and predisposing risk factors. The conditional risk factors are associated with increased risk for CHD, although their causative, independent, and quantitative contributions to CHD have not been well documented. The predisposing risk factors are those that worsen the independent risk factors. Two of these risk factors; obesity and physical inactivity, are designated major risk factors by the American Heart Association (AHA) (Fletcher *et al.*, 1996; Eckel, 1997). The adverse effects of obesity are worsened when it is expressed as abdominal obesity, an indicator of insulin resistance. These risk factors apply before clinical manifestation of coronary atherosclerotic diseases. The clinical significance of these risk assessment is to identify high-risk patients who require attention, motivate patients to adhere to risk-reduction therapies and modify the intensity of risk reduction effort required in potential patients (Grundy *et al.*, 1999).

#### **2.1. Lipoproteins, cholesterol and atherosclerosis**

Cholesterol is a building block of the outer layer of cell membranes. Cholesterol is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals (Leah, 2009). As an essential structural component of mammalian cell membranes, it is required to establish proper membrane permeability and fluidity. In addition, cholesterol is an important component for the manufacture of bile acids, steroid hormones, and vitamin D. Cholesterol is the principal sterol synthesized by animals; however, small quantities can be synthesized in other eukaryotes such as plants and fungi. It is almost completely absent among prokaryotes including bacteria (Pearson *et al*., 2003).

Owing to its limited solubility in water, cholesterol is transported in blood in lipoproteins. The lipoprotein outer layer is formed of amphiphilic cholesterol and phospholipid molecules, studded with proteins, surrounding a hydrophobic core of triglycerides and cholesterol esters. Lipoproteins are specifically targeted to cells by distinct apolipoproteins on their surface that bind to specific receptors. Low density lipoprotein (LDL) contains the highest level of cholesterol. LDL receptors in peripheral tissues bind LDL, triggering its endocytosis, lysosomal targeting and hydrolysis. When cells have abundant cholesterol, LDL receptor synthesis is inhibited by the sterol regulatory element binding proteins (SREBP) pathway (Wang *et al.*, 1993; Yokoyama *et al.*, 1993; Brown and Goldstein, 2009).

The biosynthesis of cholesterol is intensely regulated in the body with negative feedback of plasma cholesterol levels. The molecular basis of this regulation was set out by Michael Brown and Joseph Goldstein, earning them the Nobel Prize in Physiology and Medicine in 1985 (Leah, 2009). A key irreversible step of cholesterol synthesis is catalyzed by HMG-CoA reductase. Transcription of the HMG gene is controlled by SREBPs, transcription factors that bind sterol regulatory elements. SREBPs are only able to enter the nucleus when cholesterol levels fall. At other times they are tied up in a complex that includes Scap (SREBP-cleavage activating protein), an escort protein with a cholesterol-binding motif that senses cellular cholesterol levels. The SREBP pathway is now implicated in multiple regulatory aspects of lipid formation and metabolism (Brown and Goldstein, 2009).

#### **2.2. Atherogenicity of lipoprotein sub-fractions**

The first stages of cholesterol build up in the blood vessels (atherosclerosis) occur when LDL particles circulating in the blood penetrate through the inner lining of blood vessels and become trapped in the artery wall. The normal function of LDL is to deliver cholesterol to cells, where it is used in membranes or for the synthesis of steroid hormones. Cells take up cholesterol by receptor-mediated endocytosis. LDL binds to a specific LDL receptor and is internalized in an endocytic vesicle. Receptors are recycled to the cell surface, while hydrolysis in an endolysosome releases cholesterol for use in the cell. The liver removes LDL and other lipoproteins from the circulation by receptor-mediated endocytosis.

Deregulation of cholesterol levels results in the existence of more LDL in the blood than can be taken up by LDL receptors. Excess LDL is oxidized and taken up by macrophages, forming foam cells that can become trapped in the walls of blood vessels along with cells of inflammation (Zioncheck *et al.*, 1991; Young and McEneny, 2001). Fatty streaks, consisting of subendothelial collection of foam cells are initially formed in blood vessels. Small, dense LDL particles are more atherogenic than large, buoyant LDL particles, and oxidation of LDL also increases its atherogenicity. In addition, LDL belongs to the group of lipoproteins that contain apolipoprotein (apo) B-100. Some of the particles in this highly heterogeneous group contain other apolipoproteins, such as apo C-II, apo C-III, and apo E. Furthermore, some particles are larger and rich in triglycerides (large VLDL), whereas others are smaller and rich in cholesteryl esters (small VLDL, IDL). It is now known that remnant lipoproteins containing apo C-III are highly atherogenic and may be more specific measures of coronary heart disease (CHD) risk assessment than plasma triglycerides (Carmena *et al.*, 2004).

200 Lipoproteins – Role in Health and Diseases

prokaryotes including bacteria (Pearson *et al*., 2003).

lipid formation and metabolism (Brown and Goldstein, 2009).

**2.2. Atherogenicity of lipoprotein sub-fractions**

proper membrane permeability and fluidity. In addition, cholesterol is an important component for the manufacture of bile acids, steroid hormones, and vitamin D. Cholesterol is the principal sterol synthesized by animals; however, small quantities can be synthesized in other eukaryotes such as plants and fungi. It is almost completely absent among

Owing to its limited solubility in water, cholesterol is transported in blood in lipoproteins. The lipoprotein outer layer is formed of amphiphilic cholesterol and phospholipid molecules, studded with proteins, surrounding a hydrophobic core of triglycerides and cholesterol esters. Lipoproteins are specifically targeted to cells by distinct apolipoproteins on their surface that bind to specific receptors. Low density lipoprotein (LDL) contains the highest level of cholesterol. LDL receptors in peripheral tissues bind LDL, triggering its endocytosis, lysosomal targeting and hydrolysis. When cells have abundant cholesterol, LDL receptor synthesis is inhibited by the sterol regulatory element binding proteins (SREBP) pathway (Wang *et al.*, 1993; Yokoyama *et al.*, 1993; Brown and Goldstein, 2009).

The biosynthesis of cholesterol is intensely regulated in the body with negative feedback of plasma cholesterol levels. The molecular basis of this regulation was set out by Michael Brown and Joseph Goldstein, earning them the Nobel Prize in Physiology and Medicine in 1985 (Leah, 2009). A key irreversible step of cholesterol synthesis is catalyzed by HMG-CoA reductase. Transcription of the HMG gene is controlled by SREBPs, transcription factors that bind sterol regulatory elements. SREBPs are only able to enter the nucleus when cholesterol levels fall. At other times they are tied up in a complex that includes Scap (SREBP-cleavage activating protein), an escort protein with a cholesterol-binding motif that senses cellular cholesterol levels. The SREBP pathway is now implicated in multiple regulatory aspects of

The first stages of cholesterol build up in the blood vessels (atherosclerosis) occur when LDL particles circulating in the blood penetrate through the inner lining of blood vessels and become trapped in the artery wall. The normal function of LDL is to deliver cholesterol to cells, where it is used in membranes or for the synthesis of steroid hormones. Cells take up cholesterol by receptor-mediated endocytosis. LDL binds to a specific LDL receptor and is internalized in an endocytic vesicle. Receptors are recycled to the cell surface, while hydrolysis in an endolysosome releases cholesterol for use in the cell. The liver removes

Deregulation of cholesterol levels results in the existence of more LDL in the blood than can be taken up by LDL receptors. Excess LDL is oxidized and taken up by macrophages, forming foam cells that can become trapped in the walls of blood vessels along with cells of inflammation (Zioncheck *et al.*, 1991; Young and McEneny, 2001). Fatty streaks, consisting of subendothelial collection of foam cells are initially formed in blood vessels. Small, dense LDL particles are more atherogenic than large, buoyant LDL particles, and oxidation of LDL also increases its atherogenicity. In addition, LDL belongs to the group of lipoproteins that

LDL and other lipoproteins from the circulation by receptor-mediated endocytosis.

The end result is the formation of an atherosclerotic plaque which occludes the endothelial lumen and impedes blood flow, leading to myocardial infarction, the major cause of heart attacks and strokes. Although LDL levels correlate with heart attack risk, high density lipoprotein (HDL) has an inverse ratio of risk because HDL particles transport cholesterol to the liver for excretion. Modern cholesterol tests distinguish the LDL/HDL ratio as well as the overall level (Barter *et al.*, 2007). Other sub-fractions of lipoproteins such as chylomicrons, IDL and VLDL may enter the endothelial spaces due to their sizes, thus contribute substantially to development of atherosclerotic plaques. They may also increase prothrombotic factors, triggering cardiovascular diseases (Brunzell *et al.*, 2008).

**Figure 2.** Sizes of Lipoproteins available at http://www.sigmaaldrich.com/european-export.html

Triglyceride-rich lipoproteins comprise a great variety of nascent and metabolically modified lipoprotein particles differing in size, density, and lipid and apolipoprotein composition. Studies have shown an inverse relationship between the size of lipoproteins and their ability to cross the endothelial barrier to enter the arterial intima. Chylomicrons and large VLDLs are probably not capable of entering the arterial wall. On the other hand, small VLDL and IDL can enter the arterial intima. Therefore, certain triglyceride rich lipoproteins are atherogenic, whereas others are not. A large body of evidence suggests that small VLDLs and IDLs are independently associated with atherosclerosis (Carmena *et al.*, 2004).