Markers of cardiac oxidative stress and altered morphology after intraperitoneal cocaine injection in a rat model

Ameliorative effect of Metformin / alpha-lipoic acid combination on diabetic nephropathy via modulation of YAP/ miR-29a/PTEN/p-AKT axis

Diabetic nephropathy (DN) is the most frequent and serious complication of type 2 diabetes (T2DM). Lack of a precise remedy and socio-economic burden of DN patients implements searching about alternative therapies. This study aims to evaluate the possible beneficial effect of alpha-lipoic acid (α-LA) alone or in combination with metformin (Met) in ameliorating STZ/High fat diet (HFD)-induced DN. T2DM was induced via HFD administration for 15 weeks and single ip injection of STZ (35 mg/kg) at week 7. Male Sprague-Dawley rats were randomly grouped as follows: control group, STZ/HFD-induced DN, Met/T; daily treated with 150 mg/kg Met, α-LA/T group; daily treated with 100 mg/kg α-LA, and Met/T + α-LA/T group; daily treated with Met and α-LA at same doses. Administration of Met and α-LA succeeded in attenuating STZ/HFD-induced DN as manifested by significant decrease in kidney weight as well as renal and cardiac hypertrophy index. Moreover, Met and α-LA improved glycemic control, kidney functions and lipid profile as well as restored redox balance. Additionally, Met and α-LA administration significantly upregulated PTEN level accompanied by significant downregulation in renal p-AKT and miR-29a levels. Histopathologically, Met and α-LA administration mitigated STZ/HFD-induced histopathological alterations in kidney and heart. Moreover, immunohistochemical examination revealed a significant decrease in renal YAP, collagen I and Ki-67. Taken together, these observations revealed that Met and α-LA administration could protect against STZ/HFD-induced DN.

Contraction Band Necrosis with Dephosphorylated Connexin 43 in Rat Myocardium after Daily Cocaine Administration

Contraction band necrosis (CBN) is a common abnormality found in the myocardium of cocaine abusers, but is rarely reported in experimental models of cocaine abuse. Connexin 43 (Cx43) is essential for cardiac intercellular communication and the propagation of CBN. Under stress or injury, cardiac Cx43 is dephosphorylated, which is related to cardiomyocyte dysfunction and pathogenesis, whereas adiponectin exerts beneficial effects in the myocardium. In this study, we explore the effects of cocaine on cardiac Cx43 in vivo. Rats were administered cocaine via the tail vein at 20 mg/kg/day for 14 days, and showed widespread CBN, microfocal myocarditis and myocardial fibrosis, corresponding to a dysfunction of cardiac mitochondria under increased oxidative stress. The increase in dephosphorylated cardiac Cx43 and its negative correlation with the myocardial distribution of CBN after cocaine administration were determined. In addition, apoptosis and necroptosis, as well as increased adiponectin levels, were observed in the myocardium after cocaine exposure. Accordingly, we found altered profiles of cardiac Cx43, CBN and its negative correlation with dephosphorylated cardiac Cx43, and the possible involvement of adiponectin in the myocardium after 14 days of cocaine administration. The latter might play a protective role in the cardiotoxicity of cocaine. The current findings would be beneficial for establishing novel therapeutic strategies in cocaine-induced cardiac consequences.

Altered cardiac mitochondrial dynamics and biogenesis in rat after short-term cocaine administration

Abuse of the potent psychostimulant cocaine is widely established to have cardiovascular consequences. The cardiotoxicity of cocaine is mainly associated with oxidative stress and mitochondrial dysfunction. Mitochondrial dynamics and biogenesis, as well as the mitochondrial unfolded protein response (UPRmt), guarantee cardiac mitochondrial homeostasis. Collectively, these mechanisms act to protect against stress, injury, and the detrimental effects of chemicals on mitochondria. In this study, we examined the effects of cocaine on cardiac mitochondrial dynamics, biogenesis, and UPRmt in vivo. Rats administered cocaine via the tail vein at a dose of 20 mg/kg/day for 7 days showed no structural changes in the myocardium, but electron microscopy revealed a significant increase in the number of cardiac mitochondria. Correspondingly, the expressions of the mitochondrial fission gene and mitochondrial biogenesis were increased after cocaine administration. Significant increase in the expression and nuclear translocation of activating transcription factor 5, the major active regulator of UPRmt, were observed after cocaine administration. Accordingly, our findings show that before any structural changes are observable in the myocardium, cocaine alters mitochondrial dynamics, elevates mitochondrial biogenesis, and induces the activation of UPRmt. These alterations might reflect cardiac mitochondrial compensation to protect against the cardiotoxicity of cocaine.

Oxidative Stress and Cocaine Intoxication as Start Points in the Pathology of Cocaine-Induced Cardiotoxicity

Psychomotor stimulants are the most commonly used prohibited substances after cannabis. Globally, their use reaches epidemiological proportions and is one of the most common causes of death in many countries. The use of illicit drugs has negative effects on the cardiovascular system and is one of the causes of serious cardiovascular pathologies, ranging from abnormal heart rhythms to heart attacks and sudden cardiac death. The reactive oxygen species generation, toxic metabolites formation, and oxidative stress play a significant role in cocaine-induced cardiotoxicity. The aim of the present review is to assess acute and chronic cocaine toxicity by focusing on the published literature regarding oxidative stress levels. Hypothetically, this study can serve as a basis for developing a rapid and effective method for determining oxidative stress levels by monitoring changes in the redox status of patients with cocaine intoxication.

Ethanol addictively enhances the in vitro cardiotoxicity of cocaine through oxidative damage, energetic deregulation, and apoptosis

Cocaine (COC) is frequently consumed in polydrug abuse settings, and ethanol (EtOH) is the most prominent co-abused substance. Clinical data and experimental evidence suggest that the co-administration of COC with EtOH can be more cardiotoxic than EtOH or COC alone, but information on the molecular pathways involved is scarce. Since these data are crucial to potentiate the identification of therapeutic targets to treat intoxications, we sought to (i) elucidate the type of interaction that occurs between both substances, and (ii) assess the mechanisms implicated in the cardiotoxic effects elicited by COC combined with EtOH. For this purpose, H9c2 cardiomyocytes were exposed to COC (104 µM-6.5 mM) and EtOH (977 µM-4 M), individually or combined at a molar ratio based on blood concentrations of intoxicated abusers (COC 1: EtOH 9; 206 µM-110 mM). After 24 h, cell metabolic viability was recorded by the MTT assay and mixture toxicity expectations were calculated using the independent action (IA) and concentration addition (CA) models. EtOH (EC₅₀ 305.26 mM) proved to act additively with COC (EC₅₀ 2.60 mM) to significantly increase the drug in vitro cardiotoxicity, even when both substances were combined at individually non-cytotoxic concentrations. Experimental mixture testing (EC₅₀ 19.18 ± 3.36 mM) demonstrated that the cardiotoxicity was fairly similar to that predicted by IA (EC₅₀ 22.95 mM) and CA (EC₅₀ 21.75 mM), supporting additivity. Concentration-dependent increases of intracellular ROS/RNS and GSSG, depletion of GSH and ATP, along with mitochondrial hyperpolarization and activation of intrinsic, extrinsic, and common apoptosis pathways were observed both for single and combined exposures. In general, the mixture exhibited a toxicological profile that mechanistically did not deviate from the single drugs, suggesting that interventions such as antioxidant administration might aid in the clinical treatment of this type of polydrug intoxication. In a clinical perspective, the observed additive mixture effect may reflect the increased hazards at which users of this combination are exposed to in recreational settings.

Cardiovascular Mitochondrial Dysfunction Induced by Cocaine: Biomarkers and Possible Beneficial Effects of Modulators of Oxidative Stress

Cocaine abuse has long been known to cause morbidity and mortality due to its cardiovascular toxic effects. The pathogenesis of the cardiovascular toxicity of cocaine use has been largely reviewed, and the most recent data indicate a fundamental role of oxidative stress in cocaine-induced cardiovascular toxicity, indicating that mitochondrial dysfunction is involved in the mechanisms of oxidative stress. The comprehension of the mechanisms involving mitochondrial dysfunction could help in selecting the most appropriate mitochondria injury biological marker, such as superoxide dismutase-2 activity and glutathionylated hemoglobin. The potential use of modulators of oxidative stress (mitoubiquinone, the short-chain quinone idebenone, and allopurinol) in the treatment of cocaine cardiotoxic effects is also suggested to promote further investigations on these potential mitochondria-targeted antioxidant strategies.

Myocardial oxidative damage is induced by cardiac Fas-dependent and mitochondria-dependent apoptotic pathways in human cocaine-related overdose

The aim of this study is to analyse cardiac specimens from human cocaine-related overdose, to verify the hypothesis that cardiac toxicity by acute exposure to high dosage of cocaine could be mediated by unbalanced myocardial oxidative stress, and to evaluate the apoptotic response. To address these issues, biochemical and immunohistological markers of oxidative/nitrosative stress were evaluated. We found that i-NOS, NOX2 and nitrotyrosine expression were significantly higher in the hearts of subjects who had died from high doses of cocaine, compared to the control group. Increase of these markers was associated with a dramatic increase in 8-OHdG, another marker of oxidative stress. A high number of TUNEL-positive apoptotic myocells was observed in the study group compared to the control group. The immunoexpression of TNF-α was significantly higher in the cocaine group compared to the control group. Furthermore, we detected a significantly stronger immunoresponse to anti-SMAC/DIABLO in our study group compared to control cases. Both cardiac Fas-dependent and mitochondria-dependent apoptotic pathways appeared to be activated to a greater extent in the cocaine group than in the control group. Our results highlight the central role of oxidative stress in cocaine toxicity. High levels of NOS can promote the oxidation process and lead to apoptosis.

Oxidative stress biomarkers in some rat brain structures and peripheral organs underwent cocaine

Oxidative stress (OS) generates or intensifies cocaine-evoked toxicity in the brain and peripheral organs. The aim of this study was to examine superoxide dismutase (SOD) activity and lipid peroxidation [measured by malondialdehyde (MDA) levels] in rats during maintenance of cocaine self-administration and after withdrawal by a yoked-triad procedure. Our results indicate that repeated cocaine self-administration provoked an elevation of SOD activity in the hippocampus, frontal cortex, dorsal striatum, and liver. MDA levels were reduced in the brain, increased in the liver, kidney, and heart during maintenance of self-administration, and increased in the kidney in cocaine-yoked rats. In addition, following extinction training, we found enhanced MDA levels and SOD activity in the rat hippocampus, while changes in the activity of OS biomarkers in other brain structures and peripheral tissues were reminiscent of the changes seen during cocaine self-administration. These findings highlight the association between OS biomarkers in motivational processes related to voluntary cocaine intake in rats. OS participates in memory and learning impairments that could be involved in drug toxicity and addiction mechanisms. Therefore, further studies are necessary to address protective mechanisms against cocaine-induced brain and peripheral tissue damage.

Effects of hypoxia-induced intrauterine growth restriction on cardiac siderosis and oxidative stress

We have previously shown that adult rat offspring born intrauterine growth restricted (IUGR) as a result of a prenatal hypoxic insult exhibit several cardiovascular characteristics that are compatible with common manifestations of chronic iron toxicity. As hypoxia is one of the major regulators of iron absorption and metabolism, we hypothesized that hypoxia-induced IUGR offspring will have long-term changes in their ability to regulate iron metabolism leading to myocardial iron deposition and induction of myocardial oxidative stress. Pregnant Sprague Dawley rats were randomized to control (n = 8) or maternal hypoxia (11.5% oxygen; n = 8) during the last 6 days of pregnancy. At birth, litters were reduced to eight pups (four male and four female). At 4 or 12 months of age, offspring were euthanatized and samples (blood and myocardium) were collected. In only the male offspring, IUGR and aging were associated with an increase in myocardial markers of oxidative stress such as oxidized/reduced glutathione ratio and malondialdehyde. Aged male IUGR offspring also exhibited interstitial myocardial remodeling characterized by myocyte loss and disrupted extracellular matrix.Contrary to our hypothesis, however, neither IUGR nor aging were associated with changes in any systemic or local markers of iron metabolism. Our results suggest that hypoxic insults leading to IUGR produce long-term effects on the levels of oxidative stress and connective tissue distribution in the myocardium of male but not female offspring.

Effect of Ocimum sanctum, ascorbic acid, and verapamil on macrophage function and oxidative stress in mice exposed to cocaine

OBJECTIVE

To investigate the effect of Ocimum sanctum, ascorbic acid, and verapamil on macrophage function and oxidative stress in experimental animals exposed to cocaine.

MATERIALS AND METHODS

Mice were used in this study and were divided randomly into different groups of six animals each. They were either treated with intraperitoneal injection of saline or cocaine hydrochloride or an oral feeding of oil of Ocimum sanctum, ascorbic acid or verapamil, or both (ascorbic acid and verapamil), and were evaluated for a respiratory burst of macrophages, superoxide and nitric oxide (NO) production, estimation of TNF-alpha in the serum and supernatant of cultured macrophages, estimation of lipid peroxidation (malondialdehyde- MDA) in the serum, and superoxide dismutase activity in the erythrocytes.

RESULTS

Unstimulated respiratory burst as well as superoxide production was enhanced on treatment with cocaine and all the three drugs were found to attenuate this enhancement. The bactericidal capacity of macrophages decreased significantly on chronic cocaine exposure, as it was associated with decreased respiratory burst and superoxide production. There was a significant decrease in NO production by macrophages on chronic cocaine exposure and all the test drugs were found to restore nitrite formation to a normal level. There was an increase in the malonylodialdehyde (MDA) level and decrease in the superoxide dismutase level on chronic cocaine exposure, and all the three drugs effectively decreased the MDA level and increased superoxide dismutase level. There was an increase in serum TNF-alpha on chronic cocaine exposure, which was decreased significantly by ascorbic acid and verapamil.

CONCLUSION

O. sanctum, ascorbic acid, and verapamil were equally effective in improving the macrophage function and reducing oxidative stress. These findings suggested that O. sanctum, ascorbic acid, and verapamil attenuated acute and chronic cocaine-mediated effects.

Activated cell survival cascade protects cardiomyocytes from cell death in Tako-Tsubo cardiomyopathy

AIMS

Tako-Tsubo cardiomyopathy (TTC) is characterized by rapid regeneration of contractile dysfunction. From recent studies it is known that excessive catecholamine levels due to emotional or physical stress might play a central role. After sympathetic activation, the PIK3/AKT pathway is a key regulator of many cellular responses, including cytoprotective effects. Thus, the purpose of this study was to investigate whether the PIK3/AKT pathway plays a pivotal role in TTC.

METHODS AND RESULTS

A total of 16 consecutive patients diagnosed with TTC were studied. Left ventricular biopsies were taken during the acute phase and after functional recovery. Specimens were examined by quantitative RT-PCR and western blotting. Representative genes of the PI3K/AKT pathway (PIK3-R1, PTEN, GSK3beta, mTOR, PP2A, eIF4E) were compared with left ventricular controls from non-transplanted healthy hearts. PI3K expression was increased during the acute phase and after functional recovery. AKT protein levels were unaltered, but phosphorylation significantly increased during the acute phase. Both PTEN (PI3K antagonist) and PP2 (unspecific phosphatase) were down-regulated. Phosphorylation of the PI3K/AKT downstream target mTOR was increased, while expression of both GSK3 isoforms was decreased. The Bax/Bcl2 ratio was increased in the acute and recovery phases.

CONCLUSION

PI3K/AKT signalling is activated in TTC. This activated cell survival cascade might protect cardiomyocytes from cell death and also contribute to rapid regeneration in TTC.

Myocardial lesions after long-term administration of methamphetamine in rats

OBJECTIVE

To demonstrate the myocardial lesion associated with long-term administration of methamphetamine in rats.

METHODS

The experimental models of intoxication of methamphetamine were established in Sprague-Dawley rats. Methamphetamine hydrochloride (3 mg x kg(-1) x d(-1)) was subcutaneously injected to rats in methamphetamine-treated group (n = 16), and normal saline at the same dose was injected to rats in control group (n = 16). After 1 week and 8 weeks of injection, 8 rats in each group were sacrificed and their hearts were examined with light microscopy and electron microscopy, respectively.

RESULTS

After 1 week of methamphetamine exposure, foci of contraction band and cellular degeneration were present in subendocardial myocardium. Cellular degeneration, myocytolysis, and contraction band necrosis became prominent and extensive in methamphetamine-treated rats after 8 weeks. Hypertrophy, intracellular vacuolization, and fibrosis were also observed. The ultrastructural feature showed marked swelling and degeneration of mitochondria, enlargement of sarcoplasmic reticulum, and dissolution of myofilaments. No obvious cardiac myocyte lesions were observed in rats of control group.

CONCLUSION

Methamphetamine abuse daily for a long time may result in an increased risk of cardiovascular lesions similar to cardiomyopathy.

Heroin-associated myocardial damages--conventional and immunohistochemical investigations

Well-known complications related to drug abuse are myocardial insufficiency, myocardial infarction, endocarditis, myocarditis, aortic dissection, neurologic damages, ischemic colitis, thrombotic phenomenons, renal infarction and acute liver failure. Furthermore, microfocal fibrosis of the myocardium is found in stimulant abuse. The origin of myocardial fibrosis associated with opiate abuse (endocarditis, myocarditis, embolism) is still unclear. This question shall be investigated using immunohistochemical staining for early diagnosis of myocarditis. A quantification of myocardial interstitial leucocytic infiltrates was accomplished in 21 chronic drug abusers who died of heroin/morphine intoxication and compared to 15 normal subjects who died suddenly due to non-cardiac causes of death without intoxication (e.g. traffic accidents, head trauma). Toxicological investigations were performed and in addition, blood samples were checked to clarify the status of HIV, hepatitis A, B and C in both groups. To verify signs of inflammation, myocardial specimen from different locations were investigated with conventional histological stainings and immunohistochemical techniques for characterization and quantification of interstitial myocardial leucocytes, T-lymphocytes and macrophages. The number of cells were found up to fivefold increased in heroin addicts compared to the control group without reaching the cut-off values for immunohistochemically based diagnosis of myocarditis.

Cardiac oxidative stress determination and myocardial morphology after a single ecstasy (MDMA) administration in a rat model

Experimental and clinical data indicate that 3,4-methylenedioxy-N-methylamphetamine (MDMA) abuse can produce significant cardiovascular toxicity. A mechanism may be a direct toxic effect of redox active metabolites of MDMA. To evaluate the effect of a single MDMA dose on cellular antioxidant defence system and to investigate the morphology in male albino rats, total glutathione (GSH), oxidised glutathione (GSSG), ascorbic acid (AA), glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD) and malondialdehyde (MDAL) were studied. The effects were evaluated at 3, 6, 16 and 24 h after MDMA administration. Antioxidant enzymes activity was significantly reduced: GPx (-24%) and SOD (-50%) after 3 h and GR (-19%) after 6 h from treatment. AA levels decrease (-37%) after 3 h and (-30%) after 6 h; MDAL level increased (+119%) after 3 h; GSH levels decreased after 3 (31.3%) and 6 h (37.9%) from MDMA treatment. GSSG content was not affected by ecstasy administration. Myocardial contraction band necrosis (CBN) was already visible in rats killed at 6 h. After 16 h, macrophagic monocytes around the necrotic myocardial cells were observed, and within 24 h, this infiltrate became more widespread with an early removal of the necrotic material. Calcium deposits were observed within ventricular cardiomyocytes with intact nuclei and sarcomeres. Single administration of MDMA can significantly alter the cellular antioxidant defence system and produce oxidative stress which may result in lipid peroxidation and disruption of Ca(2 +) homeostasis. The depression in Ca(2+) regulatory mechanism by reactive oxygen species ultimately results in intracellular Ca(2 +) overload, CBN and cell death.

Correlation between cardiac oxidative stress and myocardial pathology due to acute and chronic norepinephrine administration in rats

Background: To investigate the cardiotoxic role of reactive oxygen species (ROS) and of products derived from catecholamines auto-oxidation, we studied: (1) the response of antioxidant cardiac cellular defence systems to oxidative stress induced by norepinephrine (NE) administration, (2) the effect of NE administration on cardiac β₁-adrenergic receptors by means of receptor binding assay, (3) the cellular morphological alterations related to the biologically cross-talk between the NE administration and cytokines [tumor necrosis factor-alpha (TNF-α), monocyte chemotactic protein-1 (MCP-1), interleukins IL6, IL8, IL10]Methods and Results: A total of 195 male rats was used in the experiment. All animals underwent electrocardiogram (EKG) before being sacrificed. The results obtained show that NE administration influences the antioxidant cellular defence system significantly increasing glutathione peroxidase (GPx) activity, glutathione reductase (GR) and superoxide dismutase (SOD). The oxidized glutathione (GSH/GSSG) ratio significantly decreases and malondialdehyde (MDA) levels increase showing a state of lipoperoxidation of cardiac tissue. We describe a significant apoptotic process randomly sparse in the damaged myocardium and the effect of ROS on the NE-mediated TNF-α, MCP-1, and IL6, IL8, IL10 production. Conclusions: Our results support the hypothesis that catecholamines may induce oxidative damage through reactive intermediates resulting from their auto-oxidation, irrespective of their interaction with adrenergic receptors, thus representing an important factor in the pathogenesis of catecholamines-induced cardiotoxicity. The rise of the cardioinhibitory cytokines may be interpreted as the adaptive response of jeopardized myocardium with respect to the cardiac dysfunction resulting from NE injection.

NADPH oxidase inhibition prevents cocaine-induced up-regulation of xanthine oxidoreductase and cardiac dysfunction

Oxidative stress is involved in the pathogenesis of cocaine-induced cardiomyopathy. In the present study, we aimed to determine the enzymatic sources of reactive oxygen species (ROS) production, namely NADPH oxidase and xanthine oxidoreductase (XOR) in male Wistar rats treated for 7 days with cocaine (2x7.5 mg/kg/day, ip) or cocaine with a NADPH oxidase inhibitor (apocynin, 50 mg/kg/day, po) or a XOR inhibitor (allopurinol, 50 mg/kg/day, po). Cocaine-induced cardiac dysfunction is associated with an increase in NADPH oxidase and XOR activities (59% and 29%, respectively) and a decrease in catalase activity. Apocynin or allopurinol treatment prevents the cocaine-induced cardiac alteration by restoration of cardiac output, stroke volume and fractional shortening. This is associated with a reduction of the myocardial production of superoxide anions and an enhancement of catalase activity. Surprisingly, apocynin treatment prevents XOR up-regulation supporting the hypothesis that NADPH oxidase-derived ROS play a role in modulating ROS production by XOR. These data suggest that NADPH and xanthine oxidase act synergically to form myocardial ROS and clearly demonstrate that their inhibition may be critical in preventing the initiation and progression of cocaine-induced LV dysfunction.

A systematic study of a myocardial lesion: Colliquative myocytolysis

BACKGROUND

The term "myocytolysis" was first used to define the repair process of contraction band necrosis associated with an acute myocardial infarction. On the other hand, in the latter condition a "myofibrillolysis," presenting edematous myocardial cells not involved by infarct necrosis, and without evidence of repair process was reported. The objective of this study is to establish the frequency, extent and meaning of this myocardial lesion.

MATERIALS AND METHODS

In 12 groups of patients for a total of 432 cases with and without coronary heart disease, "colliquative myocytolysis"--i.e., progressive vacuolization by loss of myofibrils until their total or subtotal disappearance associated with intramyocellular edema in absence of any cellular reaction--was graded in 16 histological slides of the different cardiac regions in each pathological case.

RESULTS

Colliquative myocytolysis (CM) was present in more than 90% with a maximal extent in cases of irreversible congestive heart failure followed by transplanted heart cases (67%) with a survival greater than 1 week. In all other groups, the lesion was absent or minimal.

CONCLUSIONS

No correlation was found between CM and contraction band necrosis, gender, age, heart weight, myocardial fibrosis, coronary artery stenosis, clinical data. Colliquative myocytolysis is a specific histological marker of congestive heart failure, without relation to coronary blood flow, heart weight and myocardial fibrosis. Vacuolization of myocardial cells may be due to other causes (e.g., storage disease, etc.) or may be an artifact. There is no support for the belief that coronary ischemia or myocardial hypoxia is its causes.

Chronic Exposure to Cocaine Binging Predisposes to an Accelerated Course of Dilated Cardiomyopathy in Conscious Dogs following Rapid Ventricular Pacing

Despite extensive study, the extent to which cocaine use predisposes to cardiac injury remains unknown. We hypothesized that chronic cocaine binging would increase susceptibility to a subsequent cardiac insult, even in the absence of demonstrable effects on baseline hemodynamics. We studied progression of dilated cardiomyopathy (DCM) induced by rapid ventricular pacing (240 beats per minute) in five conscious, chronically instrumented dogs, after exposure to repetitive cocaine binging (COC) in the form of four consecutive 1 mg/kg i.v. boluses daily for 8 days, to simulate human cocaine abuse. We compared the results with nine control dogs (CON) undergoing the exact pacing protocol, without prior cocaine exposure. Baseline hemodynamics were not significantly altered by chronic cocaine exposure. Following 2 weeks of pacing, COC dogs exhibited accelerated progression to DCM, depressed plasma nitric oxide levels (CON, 17 +/- 2 microM; COC, 10 +/- 2 microM, p < 0.05), and a significantly greater increase in plasma epinephrine (CON, 33 +/- 6 pg/ml; COC, 104 +/- 24 pg/ml). After only 2 weeks of pacing, COC dogs demonstrated progressive DCM of a magnitude comparable with end-stage pacing-induced DCM. Chronic cocaine binging increases susceptibility to a subsequent myocardial insult and accelerates progression of DCM in conscious dogs following rapid pacing. These data suggest that although chronic cocaine use alone may not affect myocardial function, it predisposes to greater susceptibility to a superimposed insult.

Cardiac pathology in death from electrocution

To better characterize the morphologic changes in electrocution, morphologic changes in the hearts of 21 subjects, who died instantaneously of electrocution, were compared to the hearts of decedents with different types of death. Sixteen myocardial samples per heart were processed for histological examination, and sections were prepared with a variety of specific stains. The frequency, location and extent of myocellular segmentation (stretching and/or rupture) of intercalated discs and associated changes of myocardial bundles and single myocells [myofibre break-up (MFB)] were recorded, quantitatively analysed and statistically evaluated. The frequency of MFB was maximal in cases of electrocution (90%). The findings show that MFB is an ante-mortem change and may be a distinct finding in electrocution.

Myofiberbreak-up: A marker of ventricular fibrillation in sudden cardiac death

BACKGROUND

Electrophysiologically, ventricular fibrillation is defined as a "chaotic, random, asynchronous electrical activity of the ventricles due to repetitive re-entrant excitation and/or rapid focal discharge". To this point its morphological equivalent has not been defined.

MATERIAL AND METHOD

Several groups of different diseases and types of accidental death in normal subjects were studied. A complete autopsy was performed and the hearts were examined in 432 cases. A total of 16 myocardial samples per heart were processed for histological examination and sections were stained by haematoxylin and eosin or by specific stains. The frequency, location and extent of myocellular segmentation (stretching and/or rupture) of intercalated discs and associated changes of myocardial bundles and single myocells were investigated. A quantitative analysis was performed and the data were processed for statistical evaluation.

RESULTS

The frequency of MFB was maximal in coronary (88%) and Chagas (76%) groups followed by the intracranial brain haemorrhage group (52%). The extent of myofiberbreak-up was maximal in coronary/Chagas groups followed by intracranial haemorrhage and transplant groups.

CONCLUSIONS

No correlation was seen between gender, age, heart weight, degree of coronary atherosclerosis, myocardial fibrosis, survival and MFB. If our postulate is correct, finding MFB in the myocardium might allow the diagnosis of a malignant arrhythmia followed by cardiac arrest due to ventricular fibrillation even in the absence of clinical information (sudden death out-of-hospital).

Role of oxidative metabolites of cocaine in toxicity and addiction: oxidative stress and electron transfer

Cocaine is one of the principal drugs of abuse. Although impressive advances have been made, unanswered questions remain concerning mechanism of toxicity and addiction. Discussion of action mode usually centers on receptor binding and enzyme inhibition, with limited attention to events at the molecular level. This review provides extensive evidence in support of the hypothesis that oxidative metabolites play important roles comprising oxidative stress (OS), reactive oxygen species (ROS), and electron transfer (ET). The metabolites include norcocaine and norcocaine derivatives: nitroxide radical, N-hydroxy, nitrosonium, plus cocaine iminium and formaldehyde. Observed formation of ROS is rationalized by redox cycling involving several possible ET agents. Three potential ones are present in the form of oxidative metabolites, namely, nitroxide, nitrosonium, and iminium. Most attention has been devoted to the nitroxide-hydroxylamine couple which has been designated by various investigators as the principal source of ROS. The proximate ester substituent is deemed important for intramolecular stabilization of reactive intermediates. Reduction potential of nitroxide is in accord with plausibility of ET in the biological milieu. Toxicity by cocaine, with evidence for participation of OS, is demonstrated for many body components, including liver, central nervous system, cardiovascular system, reproductive system, kidney, mitochondria, urine, and immune system. Other adverse effects associated with ROS comprise teratogenesis and apoptosis. Examples of ROS generated are lipid peroxides and hydroxyl radical. Often observed were depletion of antioxidant defenses, and protection by added antioxidants, such as, thiol, salicylate, and deferoxamine. Considerable evidence supports the contention that oxidative ET metabolites of cocaine are responsible for much of the observed OS. Quite significantly, the pro-oxidant, toxic effects, including generation of superoxide and lipid peroxyl radicals, plus depletion of glutathione, elicited by nitroxide or the hydroxylamine derivative, were greater than for the parent drug. The formaldehyde metabolite also appears to play a role. Mechanistic similarity to the action of neurotoxin 3,3'-iminodipropionitrile is pointed out. A number of literature strategies for treatment of addiction are addressed. However, no effective interventions are currently available. An hypothesis for addiction is offered based on ET and ROS at low concentrations. Radicals may aid in cell signaling entailing redox processes which influence ion transport, neuromodulation, and transcription. Ideas are suggested for future work dealing with health promotion. These include use of AOs, both dietary and supplemental, trapping of the norcocaine metabolite by non-toxic complexing agents, and use of nitrones for capturing harmful radical species.

Sudden cardiac death in a child affected by Prader-Willi syndrome

A case of sudden cardiac death in a 3-year-old young male affected by Prader-Willi syndrome, clinically diagnosed and confirmed by means of DNA methylation, is presented. The infant suddenly collapsed at home and was taken apparently unconsciousness by his mother to the emergency clinic where he was pronounced dead. A complete postmortem examination was performed and the histological findings led to the definition of cardiac death with a typical picture of contraction band necrosis. Pulmonary hypoxic alterations are frequently reported as the primary cause of death in PWS cases. In this fatal case according to the macroscopic and microscopic findings, the cause of death was most likely cardiac and possibly related to contraction band necrosis linked with ventricular fibrillation and sudden death.

Heat stroke in an incubator: an immunohistochemical study in a fatal case

The authors report the unique case of an 8-day-old infant succumbing to heat stroke caused by an abnormal increase of the environmental temperature in an incubator. At postmortem examination, second-degree burns were detected, and macroscopic and microscopic findings were typical for a heat-related death. An immunohistochemical study was performed. At the same time, a detailed examination of the incubator was conducted, revealing a malfunctioning of the temperature and relative humidity control system. We suggest that the diagnosis of heat stroke has to be confirmed on the basis of a detailed postmortem examination and a complete immunohistochemical investigation of heat shock proteins, molecules produced acutely in response to heat stress.

Selenium diet-supplementation improves cocaine-induced myocardial oxidative stress and prevents cardiac dysfunction in rats

Chronic cocaine abuse causes cardiac dysfunction and induces oxidative stress. The goal of this study was to evaluate whether an enhanced antioxidant pool, induced by the administration of selenium, may prevent the myocardial dysfunction induced by cocaine. Cocaine was administered for 7 days (15 mg/kg/day, i.p.) to rats pretreated for 4 weeks with selenium (1.16 mg/L/day, p.o.). Cardiac function was evaluated by cardiac index and left ventricular (LV) fractional shortening (FS) measured by echocardiography. The redox ratio and enzymatic activities of glutathione peroxidase (GPX) and superoxide dismutase (SOD) were measured in the LV myocardium. Cocaine administration induced a cardiac dysfunction, as evidenced by a decrease in cardiac index and LV FS as well as by an increase in LV diameters. Moreover, antioxidant markers and redox ratio were altered in rats after cocaine exposure. Selenite supplementation induced a significant limitation of cardiac index and FS alterations observed after cocaine administration. This improvement in cardiac function was associated with a redox ratio recovery while SOD and GPX activities remained unchanged. Thus, selenite reversed both the oxidative stress and the contractile dysfunction induced by cocaine administration. These results suggest a major role of oxidative stress in the cocaine-induced cardiotoxicity.

Cocaine-associated abscesses with lethal sepsis after splenic infarction in an 17-year-old woman

Well known complications related to cocaine use are myocardial insufficiency, myocardial infarction, myocarditis, aortic dissection, neurologic damages, ischemic colitis, thrombotic phenomenons, renal infarction and acute liver failure. Cases of splenic infarctions related to cocaine use are extremely rare. A 17-year-old drug addict was found by her boy-friend liveless in her bed. She was well known using cocaine since years. Autopsy revealed multiple splenic infarctions with secondary mixed bacterial infection and abscesses. Petechial bleedings were found and microabscesses in the myocardium, the meninges and the kidneys. The absolutely rare bacterial infection of the cocaine-associated splenic infarction leads to sepsis with lethal course.

Prolonged Cardiac Dysfunction After Withdrawal of Chronic Cocaine Exposure in Rats

Cocaine abuse causes myocardial dysfunction and induces oxidative stress. However, the reversibility of these effects is unknown. We evaluated myocardial function and oxidative stress after cocaine withdrawal, in a rat model of chronic cocaine exposure. Standard echocardiography and Doppler tissue imaging were performed after 4 weeks (W4) of cocaine administration (2 x 7.5 mg/kg/d, i.p.) and 4 weeks after interruption (W8). At these time points, redox state (reduced glutathione GSH, oxidized glutathione GSH, and GSH/GSSG) as well as activities of GSH peroxidase (GPX), superoxide dismutase (SOD), and catalase were determined in the left ventricle (LV). At W4, LV fractional shortening, posterior wall thickening, systolic myocardial ventricular gradient (SMVG), dP/dt(max), and dp/dt(min) were decreased, compared with control values while LV myocardial thickness was increased. At W8, even though dP/dtmax and dp/dt(min) were restored, myocardial function was still impaired as demonstrated by the decrease in posterior wall thickening, and systolic myocardial velocity gradient. At W4, CAT and GPX activities as well as GSH/GSSG ratio were reduced while SOD activity was increased. Antioxidant markers and redox ratio remained altered 4 weeks after the last injection. Thus, these data demonstrate the persistence of LV dysfunction after cocaine withdrawal, which occurs in a context of a deficit in antioxidant defenses.

Frequency and extent of contraction band necrosis in orthotopically transplanted human hearts. A morphometric study

BACKGROUND

The aims of the present study are to quantify forms of myocardial and coronary changes found at postmortem and to discuss their significance in relation to causes of death and cardiac arrest in orthotopic transplanted human hearts.

METHODS

The examined material included (1) 46 orthotopic transplanted human hearts and, as "controls", hearts from (2) 25 sudden/unexpected coronary death cases, 38 patients with acquired immunodeficiency syndrome, 34 subjects with "silent" Chagas' disease who died suddenly, 27 non cardiac patients who died from intracranial hemorrhage due to a ruptured cerebral aneurysm and 45 healthy subjects dead from head trauma.

RESULTS

Contraction band necrosis was observed in 85% of transplanted hearts, 66% of AIDS cases and in 100% Chagas' disease, 89% intracranial hemorrhage, 71% sudden coronary death, and 18% normal head trauma cases. Foci of lymphocytic infiltrate were present in 89% of transplanted heart, 50% AIDS, 100% Chagas' disease, 37% intracranial hemorrage and 64% head trauma groups. An allograft coronary vasculopathy was observed in four transplanted hearts with a survival greater than 202 days. In another 12 cases, who survived more than one year, atherosclerosis was the only coronary lesion found. No relation was observed between coronary lesions of any degree of stenosis and myocardial injuries.

CONCLUSIONS

In the group studied acute rejection was the least frequent cause (2%) of graft failure at any time following transplantation and coronary vasculopathy a questionable cause of it in four cases. Rather, contraction band necrosis as an expression of catecholamine myotoxicity seemed to play a role in graft failure related to increased myocardial catecholamine sensitivity after global denervation.

Immunosuppression and oxidative stress induced by acute and chronic exposure to cocaine in rat

The objective of the present study was to verify if immunosuppression caused by cocaine (CO) can be mediated, at least in part, by increased formation of oxidative metabolites and reactive oxygen species (ROS) in rat. Pharmacokinetics of cocaine and its metabolites, cell-mediated immune function and cytokines production, biomarkers of cell redox state maintenance and lipidic peroxidation, and variations of activity in the enzymatic systems involved in cell antioxidant defence were measured in spleen of Wistar rats acutely and chronically treated with cocaine.C(max), AUC, and t(1/2) of norcocaine (NC) significantly increased after chronic exposure to cocaine while kinetic parameters of benzoylecgonine (BE) significantly decreased. A decrease in cultured T-lymphocytes proliferation and natural killer (NK) cell activity, a high increase of immunosuppressive cytokines and a switch from Th1-type cytokines to Th2-type cytokines together with an unbalance toward anti-inflammatory cytokines recovered within 4 h after acute treatment while subsisted for 14 days after chronic treatment. A significant increase in ascorbic acid (AA), reduced glutathione and glutathione reductase (GR) with a simultaneous decrease in oxidized glutathione were observed in the first hours after acute administration. Conversely, the increase in oxidized glutathione and malondialdehyde (MDA) production and the simultaneous depletion of reduced glutathione and ascorbic acid persisted at least 24 h after chronic cocaine treatment as well as the increase in the activities of glutathione reductase, glutathione peroxidase (GPx) and superoxide dismutase (SOD). The results suggest that chronic cocaine administration affects cellular enzyme and non-enzyme-mediated antioxidant defence systems and promotes immunotoxicity in rat. Cocaine N-oxidative metabolism may be an indirect contributor, via oxidative stress.

The cocaine "body stuffer" syndrome: a fatal case

Body stuffer, sometimes called "mini packer", is the definition of someone who admits to or is strongly suspected of ingesting illegal drugs in order to escape detection by authorities, and not for recreational purposes or to transport the drug across borders. Cocaine is the drug most commonly involved in the body stuffer syndrome. Reported cases of body stuffer deaths are rare, however a fatality related to the ingestion of a plastic bag containing cocaine is described regarding a 17-year-old dealer. The authors describe how the cocaine body stuffer syndrome differs from the usual body packer. Histological and toxicological findings are examined and discussed for a better definition of this unique syndrome.