  anabolic androgenic steroids ( aass ) represent a large group of synthetic derivatives of testosterone , produced to maximize anabolic effects and minimize the androgenic ones [ 1 , 2 ] .   
the most common oral and injectable aass with their chemical structures are reported in table 1 .
androgens act by binding to the nuclear androgen receptor ( ar ) in the cytoplasm and then translocate into the nucleus .
this binding results in sequential conformational changes of the receptor affecting the interaction between receptor and protein , and receptor and dna .  
the basic structure of all steroids is a perhydro - cyclopentano phenanthrene ring system that can be modified in order to obtain several designed chemical modifications . the most important chemical modification , in which the basic structure can undergo , is reported in fig . 1 .   
anabolism is defined by kuhn   as  any state in which nitrogen is differentially retained in lean body mass , either through stimulation of protein synthesis and/or decreased breakdown of protein anywhere in the body  .
skeletal muscle can be considered as the main target tissue for the anabolic effects of aas , which are mediated by ars which after exposure to aass are up - regulated and their number increases with body building .
therefore , aass determine an increase in muscle size as a consequence of a dose - dependent hypertrophy resulting in an increase of the cross - sectional areas of both type i and type ii muscle fibers and myonucleardomains .
moreover , it has been reported that aass can increase tolerance to exercise by making the muscles more capable to overload therefore shielding them from muscle fiber damage and improving the level of protein synthesis during recovery .   despite some therapeutic use of aass ( severe burns , primary or secondary hypogonadism , short stature , hiv wasting syndrome etc . )
there is also wide abuse among athletes especially bodybuilders in order to improve their performances and to increase muscle growth and lean body mass , taking into account the significant anabolic effects above reported . not by chance
, these substances fall within the vast group of  performance - enhancing drugs  , which also include : stimulants , painkillers , sedatives and anxiolytics , diuretics , blood boosters and masking drugs .
a high - dose regimen is  stacked  by combining numerous oral and injectable aass , which are self - administered in drug 
cycles  which last from 4 to 12 weeks [ 7 - 9 ] .  
furthermore , aas users frequently associate other substances to aass , the so called  steroid - accessory drugs  , such as ephedrine , growth hormone , insulin , diuretics , ghb etc [ 10 - 15 ] for several reasons .   
the prolonged misuse and abuse of aass can determine several adverse effects , some of which may be even fatal especially on the cardiovascular system because they may increase the risk of sudden cardiac death ( scd ) , myocardial infarction , altered serum lipoproteins , and cardiac hypertrophy .
2 .   the aim of this review is to focus on deaths related to aas abuse , trying to evaluate the autoptic , histopathological and toxicological findings in order to investigate the pathophysiological mechanism that underlines this type of death , which is still obscure in several aspects .
  some databases , from 1975 to june 2014 , were searched : medline , cochrane central , scopus , web of science , science direct , embase and google scholar , using the following keywords : anabolic androgenic steroid , death , cardiovascular effects , toxicity , side / adverse effects . the main key word  anabolic androgenic steroid  was individually searched in association to each of the others .
the 189 sources found after the initial screening in order to exclude duplicate sources and retrospective studies , were selected according to the  inclusion criteria  , which allowed the identification of 10 sources . a comprehensive flow diagram with inclusion criteria
  the review of the literature using the flow diagram reported in fig . 3 allowed us to identify 19 fatal cases between 1990 and 2012 .
the most important autoptic , histopathological findings and circumstantial data are reported in table 2 , while the toxicological findings are reported in table 3 .  
of the 19 cases , 17 ( 89.5% ) were males whereas only 2 ( 10.5% ) were females .
the age ranged from 18 to 37 years ( mean age : 28  4.4 ) . among the 19 fatal cases , in 14 bodies   ( 12 males and 2 females ) the data available allowed to calculate the body mass index ( bmi ) and the results are reported in table 4 . in none of the cases the bmi was lower than 24.9 , which is considered the upper limit of the normal healthy weight .   
for all cases the autopsy excluded extracardiac causes of death , only in one case a bilateral pulmonary embolism from deep venous thrombus of lower extremities was found ( table 2 ) .   toxicological investigation performed mainly on urine samples but also in blood and hair samples , by using several screening tests and analytical methods revealed in 12 cases [ 16 , 18 , 20 - 25 ] the presence of aass and/or their metabolites in urine specimens ; in one case   nandrolone
was detected in blood , whereas in another case   stanozolol was found in hair . in the remaining 6 cases in which the toxicological analysis was negative ,
circumstantial data and evidences reported by relatives and friends of the deceased highlighted a previous prolonged use of aass .
  the chronic use of aass can cause various pathological alterations , which are related to dose , frequency and patterns of use . taking into account that numerous organs and apparatus are the target of aass
, several adverse effects can involve the liver , cardiovascular , reproductive , musculoskeletal , endocrine , renal , immunologic and hematological systems as well as some psychological effects ; a schematic representation is reported in fig .
19 fatal cases are reported ; although only single case report or small series of cases were included , whereas retrospective studies and other papers that did not fulfill the inclusion criteria were not taken into account , some consideration can be formulated ; in all cases the autopsy findings together with the histological examination have highlighted cardiac causes of death . only in one case   a mechanical cardiovascular cause of death was found ( a bilateral pulmonary embolism from deep venous thrombus of lower extremities ) . in numerous cases [ 16 ,   18 ,   19 ,   22 ,   25 ] ,
a common finding was a left ventricular hypertrophy , frequently associated with fibrosis and myocytolisis .
a myocardial hypertrophy was not found in the 4 cases reported by fineschi et al in two different reports [ 21 ,   23 ] .    what is the significance that could be attributed to the myocardial hypertrophy ?
a vigorous training in young athletes can determine a left ventricularhypertrophy , independently of the use of aass ( the so called  athlete 's heart  ) [ 25 - 28 ] .  
melchert and welder   categorized the effects of aas on the cardiovascular system into four groups of activities : vasospastic , atherogenic , thrombotic and direct myocardial injuries .
aas can induce adverse cardiovascular effects such as left ventricular hypertrophy ( lvh ) , hypertension , impaired diastolic filling , arrhythmia , erythrocytosis , thrombosis and altered lipoprotein profiles .
abnormalities in cardio - vascular reflex control of the cardiovascular system [ 31 - 35 ] and in vascular reactivity [ 36 - 40 ] have also been reported .  
studies on isolated hearts from rats treated chronically with nandrolonedecanoate ( nd ) have also shown a raise in myocardial susceptibility to ischemia / reperfusion injuries [ 41 ,   42 ] .   
nandrolone abuse combined with vigorous exercise training may lead to impaired diastolic function and concentric hypertrophy of the left ventricular ( lv ) wall .
vigorous weight lifting itself would also cause lv wall mass and thickness increase but cardiac function would not be affected . however ,
when combined with aas abuse pathological cardiac hypertrophy could be caused . in another study , rats were treated with nd for 6 weeks ( total dose 30 mg /kg ) .
rocha et al .   studied the effects on cardiac function in rats undergoing swimming training and those not undergoing it .
they investigated that swimming training combined with high doses of nandrolone ( 5 mg / kg per injection , equal to 10 mg / kg per week ) sharpens cardiac hypertrophy with interstitial fibrosis . without a doubt
. an explanation might be the change of the sympathetic autonomic activity modulated by the renin - angiotensin - system ( ras ) .
experiments have shown that ras plays a significant role in the development of lvh and myocardial fibrosis .  
angiotensin ii type 1 receptor s ( at1r s ) stimulation is associated with the regulation of cell growth and proliferation of vascular smooth muscle cells , cardiomyocytes and endothelial cells involved in endothelial dysfunction , atherosclerotic vascular phenomena , congestive heart failure and myocardial infarction .  
marques neto et al .   pointed out that the treatment with supraphysiological , chronic doses of aass induce cardiac parasympathetic disturbances in ventricular depolarization in both exercised and sedentary rats .
unambiguously , it has been shown that the blockage of the ras , and in particular of at1r by losartan , obstructs qt prolongation .  
down - regulation of ion channel subunits , kchip2 , kv1.4 and kv4.3 , could explain the autonomic dysfunction and cardiac repolarization disturbances caused by chronic treatment with supraphysiological doses of nd .
moreover , prolonged qt intervals and ventricular action potential could be explained by the reduced density of the transient outward potassium .
no augmentation in tissue collagen content or in the mrna expression of types i and iii collagens have been shown by histological analysis
the previously mentioned unconformity could be attributed to the duration of treatment with nd and the age of rats used .
participation of the potassium ( k ) current in the generation of prolonged qt and potential action duration has been noticed .
ito is the transient outward k+ current which is one of the main repolarizing currents in the mammalian myocardium and is generally believed to flow through kv1.4 , kv4.2 and kv4.3 channels in rats [ 49 ,   50 ] . in heart hypertrophic cases ito is down - regulated [ 51 - 53 ]
.    low ito density , kv1.4 and kv4.3 down - regulation in the left ventricle and prolonged action was noticed in the group treated with nandrolone compared to the control group .
homogenous distribution of kv4.3 channel in the rat s ventricular wall , higher kv4.2 in the epicardial and lower in the endocardial ventricular wall have been observed [ 49 , 50 ] .
these differences may partially explain the up - regulation of kv4.2 and prolonged qtc interval and action potential .
the expression of kchip2 is considerably decreased in heart failure and hypertrophy [ 54 ,   55 ] .
kchip2 was found to be significant for ito expression in the human heart and the correlation between kchip2 absence and a total loss of ito together with an increased susceptibility to ventricular arrhythmias in mice has been shown .   according to riezzo
the following effects were produced in physically trained mice intramuscularly treated with nd : moderate increase of heart weight , morphologically extensive cardiac hypertrophy and a wide colliquative myocytolysis which together could result in a significant heart failure .
medei et al .   found approximately 25% less nuclei and higher cardiomyocyte nuclei diameter in the ventricles of the group treated with nd .
lower nuclei suggests a toxic effect of nd which may involve a pro - apoptotic mechanism .  
tanno et al   found that nd treatment whether combined with resistance training or not induced pathological concentric hypertrophy , re - expression of fetal genes , systolic and diastolic function impairment and an incremented myocardial collagen content leading to lvh .  
increased relative left ventricle wall thickness ( rwt ) was observed as a consequence of intensive physical training in rats treated with nd compared to the respective non - trained ones . in addition , the non - trained nandrolone treated group also produced higher rwt compared to the non - trained treated group . increased interventricular septum thickness in the end - diastole ( ivsdia ) was noticed in both the non - trained nandrolone treated and trained vehicle - treated groups , compared to the non - trained vehicle treated rats .   
a considerable lower ratio of maximum early to late transmitral flow velocity ( e / a ratio ) was observed in the trained groups , in comparison with non - trained groups .
nandrolone - treated groups ( both trained and non - trained ) showed lower e / a ratio in comparison with the respective vehicle - treated groups . moreover ,
significant decrease in the expression of alpha - myosin heavy chain ( -mhc ) mrna and beta - myosin heavy chain ( -mhc ) mrna in the left ventricle was induced by nandrolone and resistance training respectively .
.   found that short - term nd treatment induces an overexpression of 2-adrenoceptors without cardiac hypertrophy .  
increment in cardiovascular mortality has been associated to an imbalance of ( ans ) activity .  
aass can acutely inhibit the reuptake of catecholamines into extraneuronal tissue   and consequently the increment of catecholamine concentrations at receptor sites occurs .
although , the neuronal catecholamine transporter is normally responsible for the reuptake of noradrenaline , it has also been proved responsible for nonexocytotic release of noradrenaline from sympathetic nerve terminals during ischemia .
an increased release of noradrenaline has been implicated in ischemia - induced arrhythmia [ 63 ,   64 ] .   
an increased activity of 6-phosphogluconate dehydrogenases and glucose-6-phosphate was observed in rat hearts , also nd activated isocitrate dehydrogenase and malic enzyme , which are other nadp - linked dehydrogenases . during the same study a significantly increased heart weight
it was shown that treatment with nd causes small qrs complex extension that might slightly reduce the spreading rate of the action potential through the heart ventricles , possibly because of the greater heart mass .  
it is known that administration of doses higher than normal ( supraphysiological ) of nd impair exercise - induced cardioprotection in treadmill - exercised rats .
chaves et al .   were the first to say that enhanced levels of antioxidant enzyme levels produced after exercise are impaired with nd treatment ( 10mg / kg for 8 weeks ) , a fact which is well correlated to the cardiac injurious effects of the drug .
it was observed that the hearts of animals treated with nandrolone and having undergone training ( dt group ) showed lower glutathione peroxidase ( gpx ) , superoxide dismutase ( sod ) and glutathione reductase ( gr ) activities compared with controls and trained groups of animals ( ct ) .
the latter observation indicates that nandrolone could act through blocking or down regulating the mechanisms implicated in the improvement of antioxidant defenses in dt animals , which might explain the lower percentage of left ventricular developed pressure and augmented infarct size in dt group .  
it has been shown , in other researches on rats that exercise training improves myocardial resistance to reperfusion injury / ischemia [ 67 - 69 ] since physiological cardiac hypertrophy amends the sensitiveness of that heart making it more resistant to the previously mentioned disorders in vivo rat hearts . notwithstanding the strenuous research efforts , the molecular mechanism(s ) involved in exercise - induced cardio protection is still debatable .   
the numerous studies above reported in animal models , especially in rats , have called into question several pathophysiological mechanisms , which may explain some of the macroscopic and microscopic finding regarding the 19 cases here reported ; however , we have to underline that these cases are single case report or small series of cases and not experimental studies .
moreover , the users of these substances frequently associate numerous steroids , in different forms , singularly and in several temporal combinations and cycles , and commonly , various steroid - accessory drugs are also used .
therefore , the interpretation of the postmortem findings is particularly difficult and no comprehensive conclusions can be done .   
finally , a brief remark must be placed regarding the bmi which was in all cases ( 12 males and 2 females ) higher than 25 .
although according to the bmi ranges from an  overweight  ( 9 cases ) to a  very severely obese  ( 2 cases ) were found , however , the bmi is not a direct measure of body fatness and bmi is calculated from an individual 's weight which includes both muscle and fat . as a result
, some subjects such as highly trained athletes may have a high bmi because of increased muscularity rather than increased body fatness ; therefore , these results should be evaluated with caution .   
the relationship between aas abuse , vigorous exercise training , and cardiac death can be evaluated only by the application of an investigative protocol , which must include a rigorous methodology covering :   a complete autopsy with a special regard to aas target organs and apparatus ( the cardiovascular system in primis ) .
a broad toxicological investigation , preceded by a careful evaluation of clinico - anamnestic data , in order to confirm an aas consumption ( including type of aass , concentration and interval of exposure ) and the possible detection of other substances which could have contributed to the fatal outcome . for this purpose ,
different matrices can be used ; urine is the most common , because it provides a prolonged detection time window , but also several other matrices such as : blood , serum , plasma , hair , oral fluid and nails can be used .   
the comparison of the cases reported here , allows us to support the hypothesis that the combined effects of strong workout , the prolonged / chronic or previous abuse of aass in different forms and combinations , have predisposed these subjects to develop different patterns of myocardial injuries and consequent sudden cardiac death [ 21 ,   23 ] .  
therefore , the authors would strengthen the  warning  already expressed in previous reports [ 21 ,   23 ] against the use / abuse of these substances among professional and non - professional athletes .
moreover , only through a careful examination of all suspicious cases of aas related deaths with the application of a rigorous investigative protocol , these cases can be identified and they could provide further information and data that may increase the knowledge of this type of deaths .
 anabolic androgenic steroids ( aass ) represent a large group of synthetic derivatives of testosterone , produced to maximize anabolic effects and minimize the androgenic ones . 
 aas can be administered orally , parenterally by intramuscular injection and transdermally . 
 androgens act by binding to the nuclear androgen receptor ( ar ) in the cytoplasm and then translocate into the nucleus . 
 this binding results in sequential conformational changes of the receptor affecting the interaction between receptor and protein , and receptor and dna.skeletal muscle can be considered as the main target tissue for the anabolic effects of aas , which are mediated by ars which after exposure to aass are up - regulated and their number increases with body building . 
 therefore , aass determine an increase in muscle size as a consequence of a dose - dependent hypertrophy resulting in an increase of the cross - sectional areas of both type i and type ii muscle fibers and myonuclear domains . 
 moreover , it has been reported that aass can increase tolerance to exercise by making the muscles more capable to overload therefore shielding them from muscle fiber damage and improving the level of protein synthesis during recovery.despite some therapeutic use of aass , there is also wide abuse among athletes especially bodybuilders in order to improve their performances and to increase muscle growth and lean body mass , taking into account the significant anabolic effects of these drugs.the prolonged misuse and abuse of aass can determine several adverse effects , some of which may be even fatal especially on the cardiovascular system because they may increase the risk of sudden cardiac death ( scd ) , myocardial infarction , altered serum lipoproteins , and cardiac hypertrophy . 
 the aim of this review is to focus on deaths related to aas abuse , trying to evaluate the autoptic , histopathological and toxicological findings in order to investigate the pathophysiological mechanism that underlines this type of death , which is still obscure in several aspects . 
 the review of the literature allowed us to identify 19 fatal cases between 1990 and 2012 , in which the autopsy excluded in all cases , extracardiac causes of death . 
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION AND CONCLUSIONS
CONFLICT OF INTEREST