Mechanisms of acute cocaine toxicity

Cocaine Effects on Reproductive Behavior and Fertility: An Overview

Cocaine is one of the most widely used drugs that, due to its molecular properties, causes various behavioral alterations, including sexual behavior. In vivo and in vitro studies conducted mainly in mammals have shown various disorders of sexual activity and morpho-functional dysfunctions of the gonads in both sexes. Although the modalities are still unclear, cocaine has been shown to alter the cell cycle, induce apoptosis, and alter sperm motility. In females, this drug alters the formation of the meiotic spindle as well as may obstruct the ovulation mechanism of mature oocytes. The data provided in this review, in addition to reviewing the current literature on the main effects of cocaine on spermatogenesis and oogenesis mainly in mammals, will hopefully provide a basic overview that may help and support further future studies on the molecular interaction of cocaine and its metabolites with germ cells.

E-cigarettes may serve as a gateway to conventional cigarettes and other addictive drugs

Electronic cigarettes (e-cigarettes) are devices that allow the user to inhale nicotine in a vapor, and are primarily marketed as a means of quitting smoking and a less harmful replacement for traditional cigarette smoking. However, further research is needed to determine if vaping nicotine via e-cigarettes can be effective. Conversely, nicotine has been considered a gateway drug to alcohol and other addictive drugs and e-cigarettes containing nicotine may have the same effects. Previous reports have shown that e-cigarette use may open the gate for the use of other drugs including conventional cigarettes, cannabis, opioids, etc. The increasing prevalence of e-cigarettes, particularly among youth and adolescents in the last decade have led to an increase in the dual use of e-cigarettes with alcohol, cannabis, and other illicit drug use like heroin and 3-4-methylenedioxymethamphetamine (MDMA). The advent of e-cigarettes as a device to self-administer addictive agents such as cocaine and synthetic cathinones may bring about additional adverse health effects associated with their concurrent use. This review aims to briefly describe e-cigarettes and their different generations, and their co-use with other addictive drugs as well as the use of the device as a tool to self-administer addictive drugs, such as cocaine, etc.

Sigma-1 receptor and seizures

Over the last decade, sigma-1 receptor (Sig1R) has been recognized as a valid target for the treatment of seizure disorders and seizure-related comorbidities. Clinical trials with Sig1R ligands are underway testing therapies for the treatment of drug-resistant seizures, developmental and epileptic encephalopathies, and photosensitive epilepsy. However, the direct molecular mechanism by which Sig1R modulates seizures and the balance between excitatory and inhibitory pathways has not been fully elucidated. This review article aims to summarize existing knowledge of Sig1R and its involvement in seizures by focusing on the evidence obtained from Sig1R knockout animals and the anti-seizure effects of Sig1R ligands. In addition, this review article includes a discussion of the advantages and disadvantages of the use of existing compounds and describes the challenges and future perspectives on the use of Sig1R as a target for the treatment of seizure disorders.

Gender differences in cocaine-induced hyperactivity and dopamine transporter trafficking to the plasma membrane

As well known, cocaine induces stimulant effects and dopamine transporter (DAT) trafficking to the plasma membrane of dopaminergic neurons. In the present study, we examined cocaine-induced hyperactivity along with cocaine-induced DAT trafficking and the recovery rate of the dopaminergic system in female rats in comparison with male rats, demonstrating interesting gender differences. Female rats are initially more sensitive to cocaine than male rats in terms of both the DAT trafficking and hyperactivity induced by cocaine. Particularly, intraperitoneal (i.p.) administration of 5 mg/kg cocaine induced significant hyperactivity and DAT trafficking in female rats but not in male rats. After repeated cocaine exposures (i.e., i.p. administration of 20 mg/kg cocaine every other day from Day 0 to Day 32), cocaine-induced hyperactivity in female rats gradually became a clear pattern of two phases, with the first phase of the hyperactivity lasting for only a few minutes and the second phase lasting for over an hour beginning at ~30 min, which is clearly different from that of male rats. It has also been demonstrated that the striatal DAT distribution of female rats may recover faster than that of male rats after multiple cocaine exposures. Nevertheless, despite the remarkable gender differences, our recently developed long-acting cocaine hydrolase, known as CocH5-Fc(M6), can similarly and effectively block cocaine-induced DAT trafficking and hyperactivity in both male and female rats.

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.

Substance use, microbiome and psychiatric disorders

Accumulating evidence from several studies has shown association between substance use, dysregulation of the microbiome and psychiatric disorders such as depression, anxiety, and psychosis. Many of the abused substances such as cocaine and alcohol have been shown to alter immune signaling pathways and cause inflammation in both the periphery and the central nervous system (CNS). In addition, these substances of abuse also alter the composition and function of the gut microbiome which is known to play important roles such as the synthesis of neurotransmitters and metabolites, that affect the CNS homeostasis and consequent behavioral outcomes. The emerging interactions between substance use, microbiome and CNS neurochemical alterations could contribute to the development of psychiatric disorders. This review provides an overview of the associative effects of substance use such as alcohol, cocaine, methamphetamine, nicotine and opioids on the gut microbiome and psychiatric disorders involving anxiety, depression and psychosis. Understanding the relationship between substance use, microbiome and psychiatric disorders will provide insights for potential therapeutic targets, aimed at mitigating these adverse outcomes.

Double Suicide Due to the Ingestion of Levamisole-Adulterated Cocaine: Case Report and Review of the Literature

Suicide is a major public health issue and the risk of attempting and committing suicide increases with age. We present the case of an elderly couple who decided to commit suicide together by self-poisoning using levamisole-adulterated cocaine. The choice of committing a double suicide, the method selected (self-poisoning), the drug self-administered (cocaine), and the route of administration (ingestion) are events rarely encountered in the forensic pathology practice, especially not in combination. In this article, we will review the literature regarding the frequency and features of these methods of suicide. An overview of the effects and mechanism of action of levamisole is also provided, highlighting the importance of including this substance and its metabolites in the routine toxicological analyses for cocaine deaths.

Safety of topical administration of nasal decongestants and vasoconstrictors in paediatric nasal surgery - A systematic review

OBJECTIVES

Topical intranasal decongestants are essential in nasal surgery to improve operative field. There are concerns regarding safety in paediatric population. Data on safety and safe dosage are limited. This systematic review evaluated the literature on safety and dosage of intranasal decongestant in paediatric population.

METHODS

We performed a systematic search of PubMed, EMBASE, Cochrane library for relevant articles. Quality assessment was done on included articles.

RESULTS

A total of 10 articles were included: five case reports; three observational studies; and two randomised control trials. Decongestants evaluated were phenylephrine, oxymetazoline, epinephrine, xylometazoline, and cocaine. In total, 209 patients were included. Side effects reported included bradycardia, tachycardia and hypertension. These were mostly self-limiting and of no clinical compromise to the patients. A total of 4/209 (1.9%) of patients required treatment for these reported effects. No mortality was reported in the included studies.

CONCLUSION

In the paediatric population, the literature suggests that when delivered in a pre-specified, controlled dosage, the haemodynamic effects of phenylephrine, oxymetazoline, xylometazoline are minimal and of no clinical significance. There is scope for further studies to establish safe dosage in the paediatric population given the paucity of current literature.

Cocaine hydrolase blocks cocaine-induced dopamine transporter trafficking to the plasma membrane

Cocaine blocks dopamine uptake via dopamine transporter (DAT) on plasma membrane of neuron cells and, as a result, produces the high and induces DAT trafficking to plasma membrane which contributes to the drug seeking or craving. In this study, we first examined the dose dependence of cocaine-induced DAT trafficking and hyperactivity in rats, demonstrating that cocaine at an intraperitoneal dose of 10 mg/kg or higher led to redistribution of most DAT to the plasma membrane while inducing significant hyperactivity in rats. However, administration of 5-mg/kg cocaine (ip) did not significantly induce DAT trafficking or hyperactivity in rats. So the threshold (intraperitoneal) dose of cocaine that can significantly induce DAT trafficking or hyperactivity should be between 5 and 10 mg/kg. These data suggest that when a cocaine dose is high enough to induce significant hyperactivity, it can also significantly induce DAT trafficking to the plasma membrane. Further, the threshold brain cocaine concentration required to induce significant hyperactivity and DAT trafficking was estimated to be ~2.0 ± 0.8 μg/g. Particularly, for treatment of cocaine abuse, previous studies demonstrated that an exogenous cocaine-metabolizing enzyme, for example, CocH3-Fc(M3), can effectively block cocaine-induced hyperactivity. However, it was unknown whether an enzyme could also effectively block cocaine-induced DAT trafficking to the plasma membrane. This study demonstrates, for the first time, that the enzyme is also capable of effectively blocking cocaine from reaching the brain even with a lethal dose of 60-mg/kg cocaine (ip) and, thus, powerfully preventing cocaine-induced physiological effects such as the hyperactivity and DAT trafficking.

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.

Computational Design and Crystal Structure of a Highly Efficient Benzoylecgonine Hydrolase

Benzoylecgonine (BZE) is the major toxic metabolite of cocaine and is responsible for the long-term cocaine-induced toxicity owing to its long residence time in humans. BZE is also the main contaminant following cocaine consumption. Here, we identified the bacterial cocaine esterase (CocE) as a BZE-metabolizing enzyme (BZEase), which can degrade BZE into biological inactive metabolites (ecgonine and benzoic acid). CocE was redesigned by a reactant-state-based enzyme design theory. An encouraging mutant denoted as BZEase2, presented a >400-fold improved catalytic efficiency against BZE compared with wild-type (WT) CocE. In vivo, a single dose of BZEase2 (1 mg kg^-1 , IV) could eliminate nearly all BZE within only two minutes, suggesting the enzyme has the potential for cocaine overdose treatment and BZE elimination in the environment by accelerating BZE clearance. The crystal structure of a designed BZEase was also determined.

Evaluation of Cocaine Effect on Endogenous Metabolites of HepG2 Cells Using Targeted Metabolomics

Cocaine toxicity has been a subject of study because cocaine is one of the most common and potent drugs of abuse. In the current study the effect of cocaine on human liver cancer cell line (HepG2) was assessed. Cocaine toxicity (IC50) on HepG2 cells was experimentally calculated using an XTT assay at 2.428 mM. The metabolic profile of HepG2 cells was further evaluated to investigate the cytotoxic activity of cocaine at 2 mM at three different time points. Cell medium and intracellular material samples were analyzed with a validated HILIC-MS/MS method for targeted metabolomics on an ACQUITY Amide column in gradient mode with detection on a triple quadrupole mass spectrometer in multiple reaction monitoring. About 106 hydrophilic metabolites from different metabolic pathways were monitored. Multivariate analysis clearly separated the studied groups (cocaine-treated and control samples) and revealed potential biomarkers in the extracellular and intracellular samples. A predominant effect of cocaine administration on alanine, aspartate, and glutamate metabolic pathway was observed. Moreover, taurine and hypotaurine metabolism were found to be affected in cocaine-treated cells. Targeted metabolomics managed to reveal metabolic changes upon cocaine administration, however deciphering the exact cocaine cytotoxic mechanism is still challenging.

The role of mitochondria in cocaine addiction

The incidence of cocaine abuse is increasing especially in the U.K. where the rates are among the highest in Europe. In addition to its role as a psychostimulant, cocaine has profound effect on brain metabolism, impacting glycolysis and impairing oxidative phosphorylation. Cocaine exposure alters metabolic gene expression and protein networks in brain regions including the prefrontal cortex, the ventral tegmental area and the nucleus accumbens, the principal nuclei of the brain reward system. Here, we focus on how cocaine impacts mitochondrial function, in particular through alterations in electron transport chain function, reactive oxygen species (ROS) production and oxidative stress (OS), mitochondrial dynamics and mitophagy. Finally, we describe the impact of cocaine on brain energy metabolism in the developing brain following prenatal exposure. The plethora of mitochondrial functions altered following cocaine exposure suggest that therapies maintaining mitochondrial functional integrity may hold promise in mitigating cocaine pathology and addiction.

Single Low Dose of Cocaine-Structural Brain Injury Without Metabolic and Behavioral Changes

Chronic cocaine use has been shown to lead to neurotoxicity in rodents and humans, being associated with high morbidity and mortality rates. However, recreational use, which may lead to addictive behavior, is often neglected. This occurs, in part, due to the belief that exposure to low doses of cocaine comes with no brain damage risk. Cocaine addicts have shown glucose metabolism changes related to dopamine brain activity and reduced volume of striatal gray matter. This work aims to evaluate the morphological brain changes underlying metabolic and locomotor behavioral outcome, in response to a single low dose of cocaine in a pre-clinical study. In this context, a Balb-c mouse model has been chosen, and animals were injected with a single dose of cocaine (0.5 mg/kg). Control animals were injected with saline. A behavioral test, positron emission tomography (PET) imaging, and anatomopathological studies were conducted with this low dose of cocaine, to study functional, metabolic, and morphological brain changes, respectively. Animals exposed to this cocaine dose showed similar open field activity and brain metabolic activity as compared with controls. However, histological analysis showed alterations in the prefrontal cortex and hippocampus of mice exposed to cocaine. For the first time, it has been demonstrated that a single low dose of cocaine, which can cause no locomotor behavioral and brain metabolic changes, can induce structural damage. These brain changes must always be considered regardless of the dosage used. It is essential to alert the population even against the consumption of low doses of cocaine.

Cocaine-regulated microRNA miR-124 controls poly (ADP-ribose) polymerase-1 expression in neuronal cells

MiR-124 is a highly expressed miRNA in the brain and regulates genes involved in neuronal function. We report that miR-124 post-transcriptionally regulates PARP-1. We have identified a highly conserved binding site of miR-124 in the 3'-untranslated region (3'UTR) of Parp-1 mRNA. We demonstrate that miR-124 directly binds to the Parp-1 3'UTR and mutations in the seed sequences abrogate binding between the two RNA molecules. Luciferase reporter assay revealed that miR-124 post-transcriptionally regulates Parp-1 3'UTR activity in a dopaminergic neuronal cell model. Interestingly, the binding region of miR-124 in Parp-1 3'UTR overlapped with the target sequence of miR-125b, another post-transcriptional regulator of Parp-1. Our results from titration and pull-down studies revealed that miR-124 binds to Parp-1 3'UTR with greater affinity and confers a dominant post-transcriptional inhibition compared to miR-125b. Interestingly, acute or chronic cocaine exposure downregulated miR-124 levels concomitant with upregulation of PARP-1 protein in dopaminergic-like neuronal cells in culture. Levels of miR-124 were also downregulated upon acute or chronic cocaine exposure in the mouse nucleus accumbens (NAc)-a key reward region of brain. Time-course studies revealed that cocaine treatment persistently downregulated miR-124 in NAc. Consistent with this finding, miR-124 expression was also significantly reduced in the NAc of animals conditioned for cocaine place preference. Collectively, these studies identify Parp-1 as a direct target of miR-124 in neuronal cells, establish miR-124 as a cocaine-regulated miRNA in the mouse NAc, and highlight a novel pathway underlying the molecular effects of cocaine.

Dopamine Receptor D1 Contributes to Cocaine Epigenetic Reprogramming of Histone Modifications in Male Germ Cells

Paternal environmental perturbations, including cocaine intake, can affect the development and behavior of the offspring through epigenetic inheritance. However, the mechanism by which cocaine alters the male germ cells epigenome is almost unexplored. Here, we report that cocaine-treated male mice showed alterations on specific histone post-translational modifications (PTMs) including increased silent chromatin marks H3K9me3 and H3K27me3 and decreased active enhancer and promoter marks H3K27ac and H3K4me3 in isolated germ cells. Also, cocaine increased H3K9ac and H4K16ac levels, involved in the replacement of histones by protamines that take place at round spermatid stage. Cocaine also altered histones H3/H4 epigenetic enzymes by increasing acetyltransferase KAT8/MOF, deacetylase SIRT1 and methyltransferase KMT1C/G9A, and decreasing deacetylases HDAC1/2 and demethylase KDM1A/LSD1 protein levels. Moreover, a pre-treatment with dopamine receptor 1 (DRD1) antagonist SCH23390 (SCH) blocked cocaine effects on H3K4me3, H3K27me3, and H4K16ac epigenetic marks. Interestingly, treatment with SCH-only was able to modify most of the histone marks tested here, pointing to a dopamine role in controlling histone PTMs in germ cells. Taken together, our data suggest a key role for DRD1 in mediating cocaine-triggered epigenetic modifications related to the silencing of gene transcription and the histone-to-protamine replacement that controls chromatin architecture of maturing sperm cells, and pinpoints a novel role of the dopaminergic system in the regulation of male germ cells reprogramming.

In vivo characterization of toxicity of norcocaethylene and norcocaine identified as the most toxic cocaine metabolites in male mice

BACKGROUND

Majority of cocaine users also consume alcohol, and concurrent use of cocaine and alcohol produces cocaethylene, norcocaine, norcocaethylene, and other non-toxic metabolites. It is essential to know their relative toxicity for development of a truly effective therapeutics for cocaine toxicity treatment.

METHODS

Drug (norcocaethylene or norcocaine)-induced acute toxicity was characterized by the occurrence (and the timing) of prostration, seizure, and death after intraperitoneal administration of the drug (n = 15) using the same strain (Swiss Webster) of male mice reported in previous study by Hearn et al. to determine LD₅₀ of cocaine and cocaethylene. In addition, drug (cocaine, cocaethylene, norcocaine, or norcocaethylene)-induced hyperactivity was determined by locomotor activity testing (n = 8).

RESULTS

According to the animal data, norcocaethylene (LD₅₀=∼39.4 mg/kg) and norcocaine (LD₅₀=∼49.7 mg/kg) are the most toxic metabolites, but they do not induce significant hyperactivity. In addition, the relative toxicity of drugs correlates with the time to the occurrence of prostration/seizure/death after the drug administration.

CONCLUSIONS

The relative toxicity of these toxic drugs can be ranked in this order: norcocaethylene > norcocaine > cocaethylene > cocaine. The data suggest that norcocaethylene, norcocaine, and cocaethylene are all significant contributors to acute toxicity of cocaine in concurrent use of cocaine and alcohol. Hence, future therapeutic development for cocaine toxicity treatment must account for detoxification of these more toxic metabolites. In addition, the relative toxicity of different drugs correlates with the average time to the occurrence of death, seizure, or prostration after the drug administration with a same dose close to their LD₅₀ values.

Evaluation of the cholinesterase activity of a potential therapeutic cocaine esterase for cocaine overdose

BACKGROUND

Cocaine is a commonly abused drug and there is no approved medication specifically to treat its addiction or overdose. Bacterial cocaine esterase (CocE)-derived RBP-8000 is currently under clinical development for cocaine overdose treatment. It is proven to be effective for human use to accelerate cocaine metabolism into physiologically inactive products. Besides cocaine, RBP-8000 may hydrolyze the neurotransmitter acetylcholine (ACh), however, no study has reported its cholinesterase activity. The present study aims to examine RBP-8000's cholinesterase activity and substrate selectivity to address the potential concern that this enzyme therapy might produce cholinergic side-effects.

METHODS

Both computational modeling and experimental kinetic analysis were carried out to characterize the potential cholinesterase activity of RBP-8000. Substrates interacting with RBP-8000 were modeled for their enzyme-substrate binding complexes. In vitro enzymatic kinetic parameters were measured using Ellman's colorimetric assay and analyzed by Michaelis-Menten kinetics.

RESULTS

It is the first demonstration that RBP-8000 catalyzes the hydrolysis of acetylthiocholine (ATC). However, its catalytic efficiency (k_cat/K_M) against ATC is 1000-fold and 5000-fold lower than it against cocaine at 25 °C and 37 °C, respectively, suggesting RBP-8000 has the desired substrate selectivity for cocaine over ACh.

CONCLUSION

Given the fact that clinically relevant dose of RBP-8000 displays insignificant cholinesterase activity relative to endogenous cholinesterases in human, administration of RBP-8000 is unlikely to produce any significant cholinergic side-effects. This study provides supplemental evidences in support of further development of RBP-8000 towards a clinically used pharmacotherapy for cocaine overdose.

Preventative effects of aripiprazole and quetiapine on seizure and lethality in a mice cocaine toxicity model: an experimental study

Objective

To assess the effectiveness of pre-treatment with aripiprazole and quetiapine to prevent acute cocaine toxicity in a mouse model of cocaine toxicity.

Methods

This experimental study included three groups (n = 25 per group) of mice that were intraperitoneally injected with normal saline solution, 10 mg/kg quetiapine or 10 mg/kg aripiprazole 15 min before 105 mg/kg cocaine hydrochloride. When the cocaine administration was completed, researchers blinded to the study groups observed the mice in terms of seizures and death for a further 30 min.

Results

In the cocaine + quetiapine group, the mean ± SE time to the first seizure was 10.80 ± 2.27 min and seizure activity was detected in 18 mice (72%) by the end of the 30 min. In the cocaine + aripiprazole group, the mean ± SE time to the first seizure was 18.10 ± 1.94 min and seizure activity was detected in 15 mice (60%) by the end of the 30 min. When compared with the control group, there was a significant difference between the cocaine + quetiapine and cocaine + aripiprazole groups in terms of seizure activity. Survival time was increased in the cocaine + aripiprazole group compared with the control and cocaine + quetiapine groups.

Conclusion

Quetiapine and aripiprazole pre-treatment reduced seizure activity and delayed the onset of seizures compared with the control group.

Mitigation of cocaine-mediated mitochondrial damage, defective mitophagy and microglial activation by superoxide dismutase mimetics

Although cocaine exposure has been shown to potentiate neuroinflammation by upregulating glial activation in the brain, the role of mitophagy in this process remains an enigma. In the present study, we sought to examine the role of impaired mitophagy in cocaine-mediated activation of microglia and to determine the ameliorative potential of superoxide dismutase mimetics in this context. Our findings demonstrated that exposure of mouse primary microglial cells (mPMs) to cocaine resulted in decreased mitochondrial membrane potential, that was accompanied by increased expression of mitophagy markers, PINK1 and PRKN. Exposure of microglia to cocaine also resulted in increased expression of DNM1L and OPTN with a concomitant decrease in the rate of mitochondrial oxygen consumption as well as impaired mitochondrial functioning. Additionally, in the presence of cocaine, microglia also exhibited upregulated expression of autophagosome markers, BECN1, MAP1LC3B-II, and SQSTM1. Taken together, these findings suggested diminished mitophagy flux and accumulation of mitophagosomes in the presence of cocaine. These findings were further confirmed by imaging techniques such as transmission electron microscopy and confocal microscopy. Cocaine-mediated activation of microglia was further monitored by assessing the expression of the microglial marker (ITGAM) and the inflammatory cytokine (Tnf, Il1b, and Il6) mRNAs. Pharmacological, as well as gene-silencing approaches aimed at blocking both the autophagy/mitophagy and SIGMAR1 expression, underscored the role of impaired mitophagy in cocaine-mediated activation of microglia. Furthermore, superoxide dismutase mimetics such as TEMPOL and MitoTEMPO were shown to alleviate cocaine-mediated impaired mitophagy as well as microglial activation.Abbreviations: 3-MA: 3-methyladenine; Δψm: mitochondrial membrane potential; ACTB: actin, beta; AIF1: allograft inflammatory factor 1; ATP: adenosine triphosphate; BAF: bafilomycin A₁; BECN1: beclin 1, autophagy related; CNS: central nervous system; DNM1L: dynamin 1 like; DMEM: Dulbecco modified Eagle medium; DAPI: 4,6-Diamidino-2-phenylindole; DRD2: dopamine receptor D2; ECAR: extracellular acidification rate; FBS: fetal bovine serum; FCCP: Trifluoromethoxy carbonylcyanide phenylhydrazone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; IL1B: interleukin 1, beta; IL6: interleukin 6; ITGAM: integrin subunit alpha M; MAP1LC3B: microtubule-associated protein 1 light chain 3 beta; mPMs: mouse primary microglial cells; MRC: maximal respiratory capacity; NFKB: nuclear factor kappa B; NLRP3: NLR family pyrin domain containing 3; NTRK2: neurotrophic receptor tyrosine kinase 2; OCR: oxygen consumption rate; OPTN: optineurin; PBS: phosphate buffered saline; PINK1: PTEN induced putative kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; ROS: reactive oxygen species; siRNA: small interfering RNA; SQSTM1: sequestosome 1; TNF: tumor necrosis factor.

A Novel Role of Prolidase in Cocaine-Mediated Breach in the Barrier of Brain Microvascular Endothelial Cells

Cocaine use is associated with breach in the blood brain barrier (BBB) and increased HIV-1 neuro-invasion. We show that the cellular enzyme "Prolidase" plays a key role in cocaine-induced disruption of the BBB. We established a barrier model to mimic the BBB by culturing human brain microvascular endothelial cells (HBMECs) in transwell inserts. In this model, cocaine treatment enhanced permeability of FITC-dextran suggesting a breach in the barrier. Interestingly, cocaine treatment increased the activity of matrix metallo-proteinases that initiate degradation of the BBB-associated collagen. Cocaine exposure also induced prolidase expression and activity in HBMECs. Prolidase catalyzes the final and rate-limiting step of collagen degradation during BBB remodeling. Knock-down of prolidase abrogated cocaine-mediated increased permeability suggesting a direct role of prolidase in BBB breach. To decipher the mechanism by which cocaine regulates prolidase, we probed the inducible nitric oxide synthase (iNOS) mediated phosphorylation of prolidase since mRNA levels of the protein were not altered upon cocaine treatment. We observed increased iNOS expression concurrent with increased prolidase phosphorylation in cocaine treated cells. Subsequently, inhibition of iNOS decreased prolidase phosphorylation and reduced cocaine-mediated permeability. Finally, cocaine treatment increased transmigration of monocytic cells through the HBMEC barrier. Knock-down of prolidase reduced cocaine-mediated monocyte transmigration, establishing a key role of prolidase in cocaine-induced breach in endothelial cell barrier.

Genome-edited skin epidermal stem cells protect mice from cocaine-seeking behaviour and cocaine overdose

Cocaine addiction is associated with compulsive drug-seeking, and exposure to the drug or to drug-associated cues leads to relapse, even after long periods of abstention. A variety of pharmacological targets and behavioral interventions have been explored to counteract cocaine addiction, but to date no market-approved medications for treating cocaine addiction or relapse exist, and effective interventions for acute emergencies resulting from cocaine overdose are lacking. We recently demonstrated that skin epidermal stem cells can be readily edited by using CRISPR (clustered regularly interspaced short palindromic repeats) and then transplanted back into the donor mice. Here, we show that the transplantation, into mice, of skin cells modified to express an enhanced form of butyrylcholinesterase, an enzyme that hydrolyzes cocaine, enables the long-term release of the enzyme and efficiently protects the mice from cocaine-seeking behavior and cocaine overdose. Cutaneous gene therapy through skin transplants that elicit drug elimination may offer a therapeutic option to address drug abuse.

Genetic depletion of p53 attenuates cocaine-induced hepatotoxicity in mice

Cocaine, an addictive drug, is known to induce hepatotoxicity via oxidative damage and proapoptosis. Since p53, a tumor suppressor gene, plays a major role in inducing oxidative stress and apoptosis, we examined the role of p53 inhibition against cocaine-induced hepatotoxicity. Cocaine treatment significantly increased oxidative parameters (i.e., reactive oxygen species, 4-hydroxylnonenal, and protein carbonyl) in the liver of wild type (WT) mice. We found that the pharmacological (i.e. pifithrin-α) and genetic (i.e. p53 knockout) inhibition of p53 significantly attenuates cocaine-induced hepatotoxicity. Cocaine treatment increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in the serum of mice, signifying hepatic damage. Consistently, these increases were attenuated by inhibition of p53, implying protection against cocaine-induced hepatic damage. In addition, cocaine treatment significantly increased PKCδ, cleaved PKCδ and p53 levels in the liver of WT mice. These increases were followed by the interaction between p53 and PKCδ, and pro-apoptotic consequences (i.e., cytosolic release of cytochrome c, activation of caspase-3, increase in Bax level and decreases in Bcl-2 and Bcl-xL levels). These changes were attenuated by p53 depletion, reflecting that the critical role of PKCδ in p53-mediated apoptotic potentials. Combined, our results suggest that the inhibition of p53 is important for protection against oxidative burdens, pro-apoptotic events, and hepatic degeneration induced by cocaine.

E-cigarettes-An unintended illicit drug delivery system

Since the introduction of electronic cigarettes (e-cigarettes) in 2003, the technology has advanced allowing for greater user modifications, with users now able to control voltage, battery power, and constituents of the e-cigarette liquid. E-cigarettes have been the subject of a growing body of research with most research justifiably focused on the chemical makeup and risk analysis of chemicals, metals, and particulates found in e-cigarette liquids and vapor. Little research to date has focused on assessing the risks associated with the drug delivery unit itself and its potential for use as an illicit drug delivery system. In light of this, a range of illicit drugs was researched focusing on pharmacodynamics, usual method of administration, the dosage required for toxicity, toxic effects, and evidence of existing use in e-cigarettes in both literature and online illicit drug forums. A systematic literature search found evidence of current use of e-cigarettes to vape almost all illicit drug types analyzed. This presents both a potential population health risk and a management issue for clinicians. It also raises the issue of policing illicit drugs due to potential altered characteristic smells and storage within e-cigarette fluids. E-cigarettes are a viable illicit drug delivery system with evidence both inside and outside of the formal medical literature detailing their potential use for drug delivery of a wide range of illicit and legal drugs.

Protein kinase Cδ knockout mice are protected from cocaine-induced hepatotoxicity

We investigated whether protein kinase Cδ (PKCδ) mediates cocaine-induced hepatotoxicity in mice. Cocaine treatment (60 mg/kg, i.p.) significantly increased cleaved PKCδ expression in the liver of wild-type (WT) mice, and led to significant increases in oxidative parameters (i.e., reactive oxygen species, 4-hydroxylnonenal and protein carbonyl). These cocaine-induced oxidative burdens were attenuated by pharmacological (i.e., rottlerin) or genetic depletion of PKCδ. We also demonstrated that treatment with cocaine resulted in significant increases in nuclear factor erythroid-2-related factor 2 (Nrf-2) nuclear translocation and increased Nrf-2 DNA-binding activity in wild-type (WT) mice. These increases were more pronounced in the rottlerin-treated WT or PKCδ knockout mice than in the saline-treated WT mice. Although cocaine treatment increased Nrf-2 nuclear translocation, DNA binding activity, and γ-glutamyl cysteine ligases (i.e., GCLc and GCLm) mRNA expressions, while it reduced the glutathione level and GSH/GSSG ratio. These decreases were attenuated by PKCδ depletion. Cocaine treatment significantly increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in the serum of WT mice signifying the hepatic damage. These increases were also attenuated by PKCδ depletion. In addition, cocaine-induced hepatic degeneration in WT mice was evident 1 d post-cocaine. At that time, cocaine treatment decreased Bcl-2 and Bcl-xL levels, and increased Bax, cytosolic cytochrome c, and cleaved caspase-3 levels. Pharmacological or genetic depletion of PKCδ significantly ameliorated the pro-apoptotic properties and hepatic degeneration. Therefore, our results suggest that inhibition of PKCδ, as well as activation of Nrf-2, is important for protecting against hepatotoxicity induced by cocaine.

Cocaine toxicological findings in cases of violent death in Sao Paulo city - Brazil

Violence is a dreadful phenomenon spread throughout the world, resulting in unfortunate events that can ultimately cause death. It is known that some countries play a much worrying role in this scenario than others. Brazil is one of them. The present work has focused on identifying the use of cocaine in 105 postmortem cases arriving at the Institute of Legal Medicine of Sao Paulo (IML-SP), the largest Brazilian city. Both blood and hair samples have been analyzed through ultra-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) in order to distinguish between recent or chronic cocaine use. The purpose of this work was to evaluate the proportion of cocaine use amongst violent individuals whose violence has ultimately led to their death. In order to do so, two previous methods, validated in-house, based on methanolic extraction for hair and protein precipitation for blood, have been used for this purpose and the final residue was analyzed through UPLC-ESI-MS/MS system. When looking at the demographics from the 105 postmortem cases analyzed, the results have shown the most critical age range to be between 18 and 25 years old and the least frequent between 37 and 45 years old. Gender wise, a rather extreme difference was found as 97 of the individuals were men and finally, considering the manner of death, the four-category criteria established appear to be fairly similar with 34 cases related to general violence and risk behavior, 26 to drug abuse suspicion, 23 to homicide resulting from opposition to police intervention and 22 to possible suicide.

Cocaine alters the mouse testicular epigenome with direct impact on histone acetylation and DNA methylation marks

RESEARCH QUESTION

Recent evidence suggests that cocaine administration in animal models can trigger non-genetic inheritance of addiction traits from father to offspring, affecting development and behaviour. Is chronic cocaine intake involved in alterations of epigenetic homeostasis in the testis?

DESIGN

Epigenetic marks and mediators in testis and isolated germ cells of adult mice treated with cocaine (10 mg/kg) or vehicle (sterile saline solution) were evaluated in an intermittent binge protocol: three intraperitoneal injections, 1 h apart, one day on/off for 13 days, collecting tissue 24 h after the last binge administration (day 14).

RESULTS

It was shown that chronic cocaine intake in mice disrupts testicular epigenetic homeostasis, increasing global methylated cytosine levels in DNA from germ cells and sperm. Cocaine also increased testicular and germ cell acetylated histone 3 and 4 and decreased expression of histone deacetylases HDAC1/2. Immunolocalization studies showed that HDAC1/2 and acetylated histone 3 and 4 proteins localize to meiotic germ cells. Analysis of mRNA expression in isolated germ cells shows decreased levels of Hdac1/2/8, Dnmt3b and Tet1 and increased levels of Dnmt3a gene expression after cocaine treatment.

CONCLUSIONS

Cocaine intake is associated with testicular toxicity and significant reproductive function impairment. The results presented here broaden the basic knowledge of the impact of addictive stimulants on testicular pathophysiology, fertility and male reproductive health and imply that altered epigenetic homeostasis by cocaine may have potential consequences on future generations.

Effectiveness of a Cocaine Hydrolase for Cocaine Toxicity Treatment in Male and Female Rats

Development of a truly effective medication for treatment of cocaine abuse has been a grand challenge. There is no FDA-approved therapeutic agent specific for cocaine addiction or overdose. An enzyme therapy using an efficient cocaine-metabolizing enzyme could be a promising treatment strategy for cocaine overdose and addiction. One of our previously designed cocaine hydrolases (CocHs), known as CocH1, was fused with human serum albumin (HSA) to prolong the biological half-life. The fusion protein CocH1-HSA is an investigational new drug (IND) approved by the FDA for clinical trials in cocaine addiction treatment, but not in cocaine overdose/toxicity treatment. In the present study, we aimed to evaluate the pharmacokinetic profile of CocH1-HSA and its effectiveness for cocaine toxicity treatment in male and female rats and demonstrate the clinical potential. The data demonstrate that enzyme CocH1-HSA has very similar pharmacokinetic profile in male and female rats. For both male and female rats, the enzyme can rapidly eliminate cocaine even if the cocaine dose is as high as 180 mg/kg (LD₁₀₀). Based on the animal data, whenever the enzyme is given to a living subject, the remaining cocaine in the body will be converted rapidly to physiologically inactive metabolites and, thus, reverse the cocaine toxicity and help the subject to recover. So, an enzyme therapy using CocH1-HSA can effectively treat cocaine toxicity and prevent the subject from further damage by cocaine. The data obtained clearly demonstrate the promising clinical potential of CocH1-HSA in cocaine overdose treatment for both genders.

Clinical Potential of an Enzyme-based Novel Therapy for Cocaine Overdose

It is a grand challenge to develop a truly effective medication for treatment of cocaine overdose. The current available, practical emergence treatment for cocaine overdose includes administration of a benzodiazepine anticonvulsant agent (e.g. diazepam) and/or physical cooling with an aim to relieve the symptoms. The inherent difficulties of antagonizing physiological effects of drugs in the central nervous system have led to exploring protein-based pharmacokinetic approaches using biologics like vaccines, monoclonal antibodies, and enzymes. However, none of the pharmacokinetic agents has demonstrated convincing preclinical evidence of clinical potential for drug overdose treatment without a question mark on the timing used in the animal models. Here we report the use of animal models, including locomotor activity, protection, and rescue experiments in rats, of drug toxicity treatment with clinically relevant timing for the first time. It has been demonstrated that an efficient cocaine-metabolizing enzyme developed in our previous studies can rapidly reverse the cocaine toxicity whenever the enzyme is given to a living rat, demonstrating promising clinical potential of an enzyme-based novel therapy for cocaine overdose as a successful example in comparison with the commonly used diazepam.

Poly (ADP-Ribose) Polymerase-1 (PARP-1) Induction by Cocaine Is Post-Transcriptionally Regulated by miR-125b

Cocaine exposure alters gene expression in the brain via methylation and acetylation of histones along with methylation of DNA. Recently, poly (ADP-ribose) polymerase-1 (PARP-1) catalyzed PARylation has been reported as an important regulator of cocaine-mediated gene expression. In this study, we report that the cellular microRNA “miR-125b” plays a key role for cocaine-induced PARP-1 expression. Acute and chronic cocaine exposure resulted in the downregulation of miR-125b concurrent with upregulation of PARP-1 in dopaminergic neuronal cells and nucleus accumbens (NAc) of mice but not in the medial prefrontal cortex (PFC) or ventral tegmental area (VTA). In silico analysis predicted a binding site of miR-125b in a conserved 3’-untranslated region (3’UTR) of the PARP-1 mRNA. Knockdown and overexpression studies showed that miR-125b levels negatively correlate with PARP-1 protein expression. Luciferase reporter assay using a vector containing the 3’UTR of PARP-1 mRNA confirmed regulation of PARP-1 by miR-125b. Specific nucleotide mutations within the binding site abrogated miR-125b’s regulatory effect on PARP-1 3’UTR. Finally, we established that downregulation of miR-125b and concurrent upregulation of PARP-1 is dependent on binding of cocaine to the dopamine transporter (DAT). Collectively, these results identify miR-125b as a post-transcriptional regulator of PARP-1 expression and establish a novel mechanism underlying the molecular effects of cocaine action.

Cocaine-Mediated Autophagy in Astrocytes Involves Sigma 1 Receptor, PI3K, mTOR, Atg5/7, Beclin-1 and Induces Type II Programed Cell Death

Cocaine, a commonly used drug of abuse, has been shown to cause neuropathological dysfunction and damage in the human brain. However, the role of autophagy in this process is not defined. Autophagy, generally protective in nature, can also be destructive leading to autophagic cell death. This study was designed to investigate whether cocaine induces autophagy in the cells of CNS origin. We employed astrocyte, the most abundant cell in the CNS, to define the effects of cocaine on autophagy. We measured levels of the autophagic marker protein LC3II in SVGA astrocytes after exposure with cocaine. The results showed that cocaine caused an increase in LC3II level in a dose- and time-dependent manner, with the peak observed at 1 mM cocaine after 6-h exposure. This result was also confirmed by detecting LC3II in SVGA astrocytes using confocal microscopy and transmission electron microscopy. Next, we sought to explore the mechanism by which cocaine induces the autophagic response. We found that cocaine-induced autophagy was mediated by sigma 1 receptor, and autophagy signaling proteins p-mTOR, Atg5, Atg7, and p-Bcl-2/Beclin-1 were also involved, and this was confirmed by using selective inhibitors and small interfering RNAs (siRNAs). In addition, we found that chronic treatment with cocaine resulted in cell death, which is caspase-3 independent and can be ameliorated by autophagy inhibitor. Therefore, this study demonstrated that cocaine induces autophagy in astrocytes and is associated with autophagic cell death.

Cocaine Enhances HIV-1 Transcription in Macrophages by Inducing p38 MAPK Phosphorylation

Cocaine is a commonly used illicit drug among HIV-1 infected individuals and is known to increase HIV-1 replication in permissive cells including PBMCs, CD4(+) T cells, and macrophages. Cocaine's potentiating effects on HIV-1 replication in macrophages- the primary targets of the virus in the central nervous system, has been suggested to play an important role in HIV-1 neuro-pathogenesis. However, the mechanism by which cocaine enhances HIV-1 replication in macrophages remain poorly understood. Here, we report the identification of cocaine-induced signaling events that lead to enhanced HIV-1 transcription in macrophages. Treatment of physiologically relevant concentrations of cocaine enhanced HIV-1 transcription in a dose-dependent manner in infected THP-1 monocyte-derived macrophages (THP-1macs) and primary monocyte-derived macrophages (MDMs). Toward decoding the underlying mechanism, results presented in this report demonstrate that cocaine induces the phosphorylation of p38 mitogen activated protein kinase (p38 MAPK), a known activator of HIV-1 transcription. We also present data suggesting that the p38 MAPK-driven HIV-1 transcription is dependent on the induction of mitogen- and stress-activated protein kinase 1 (MSK1). Consequently, MSK1 mediates the phosphorylation of serine 10 residue of histone 3 (H3 Ser10), which is known to activate transcription of genes including that of HIV-1 in macrophages. Importantly, our results show that inhibition of p38 MAPK/MSK1 signaling by specific pharmacological inhibitors abrogated the positive effect of cocaine on HIV-1 transcription. These results validate the functional link between cocaine and p38 MAPK/MSK1 pathways. Together, our results demonstrate for the first time that the p38 MAPK/MSK1 signaling pathway plays a critical role in the cocaine-induced potentiating effects on HIV-1 infection, thus providing new insights into the interplay between cocaine abuse and HIV-1 neuro-pathogenesis.

Coca: The History and Medical Significance of an Ancient Andean Tradition

Coca leaf products are an integral part of the lives of the Andean peoples from both a cultural and traditional medicine perspective. Coca is also the whole plant from which cocaine is derived. Coca products are thought to be a panacea for health troubles in regions of South America. This review will examine the toxicology of whole coca and will also look at medicinal applications of this plant, past, present, and future.

Cocaine occupancy of sigma1 receptors and dopamine transporters in mice

Activation of sigma1 (σ1) receptors contributes to the behavioral and toxic effects of (-)-cocaine. We studied a key step, the ability of (-)-cocaine to occupy σ1 receptors in vivo, using CD-1(®) mice and the novel radioligand [(125) I]E-N-1-(3'-iodoallyl)-N'-4-(3",4"-dimethoxyphenethyl)-piperazine ([(125) I]E-IA-DM-PE-PIPZE). (-)-Cocaine displayed an ED50 of 68 μmol/kg for inhibition of specific radioligand binding in whole brain, with values between 73 and 80 μmol/kg for heart, lung, and spleen. For comparison, an ED50 of 26 μmol/kg for (-)-cocaine occupancy of striatal dopamine transporters (DAT) was determined by inhibition of [(125) I]3β-(4-iodophenyl)tropan-2β-carboxylic acid isopropyl ester ([(125) I]RTI-121) binding. A chief finding is the relatively small potency difference between (-)-cocaine occupancy of σ1 receptors and the DAT, although the DAT occupancy is likely underestimated. Interactions of (-)-cocaine with σ1 receptors were assessed further using [(125) I]E-IA-DM-PE-PIPZE for regional cerebral biodistribution studies and quantitative ex vivo autoradiography of brain sections. (-)-Cocaine binding to cerebral σ1 receptors proved directly proportional to the relative site densities known for the brain regions. Nonradioactive E-IA-DM-PE-PIPZE gave an ED50 of 0.23 μmol/kg for occupancy of cerebral σ1 receptors, and a 3.16 μmol/kg (i.p.) dose attenuated (-)-cocaine-induced locomotor hyperactivity by 30%. This effect did not reach statistical significance, but suggests that E-IA-DM-PE-PIPZE is a probable σ1 receptor antagonist. As groundwork for the in vivo studies, we used standard techniques in vitro to determine ligand affinities, site densities, and pharmacological profiles for the σ1 and σ2 receptors expressed in CD-1(®) mouse brain.

Cysteine Metabolism and Oxidative Processes in the Rat Liver and Kidney after Acute and Repeated Cocaine Treatment

The role of cocaine in modulating the metabolism of sulfur-containing compounds in the peripheral tissues is poorly understood. In the present study we addressed the question about the effects of acute and repeated (5 days) cocaine (10 mg/kg i.p.) administration on the total cysteine (Cys) metabolism and on the oxidative processes in the rat liver and kidney. The whole pool of sulfane sulfur, its bound fraction and hydrogen sulfide (H₂S) were considered as markers of anaerobic Cys metabolism while the sulfate as a measure of its aerobic metabolism. The total-, non-protein- and protein- SH group levels were assayed as indicators of the redox status of thiols. Additionally, the activities of enzymes involved in H₂S formation (cystathionine γ-lyase, CSE; 3-mercaptopyruvate sulfurtransferase, 3-MST) and GSH metabolism (γ-glutamyl transpeptidase, γ-GT; glutathione S-transferase, GST) were determined. Finally, we assayed the concentrations of reactive oxygen species (ROS) and malondialdehyde (MDA) as markers of oxidative stress and lipid peroxidation, respectively. In the liver, acute cocaine treatment, did not change concentrations of the whole pool of sulfane sulfur, its bound fraction, H₂S or sulfate but markedly decreased levels of non-protein SH groups (NPSH), ROS and GST activity while γ-GT was unaffected. In the kidney, acute cocaine significantly increased concentration of the whole pool of sulfane sulfur, reduced the content of its bound fraction but H₂S, sulfate and NPSH levels were unchanged while ROS and activities of GST and γ-GT were reduced. Acute cocaine enhanced activity of the CSE and 3-MST in the liver and kidney, respectively. Repeatedly administered cocaine enhanced the whole pool of sulfane sulfur and reduced H₂S level simultaneously increasing sulfate content both in the liver and kidney. After repeated cocaine, a significant decrease in ROS was still observed in the liver while in the kidney, despite unchanged ROS content, a marked increase in MDA level was visible. The repeated cocaine decreased 3-MST and increased γ-GT activities in both organs but reduced GST in the kidney. Our results show that cocaine administered at a relatively low dose shifts Cys metabolism towards the formation of sulfane sulfur compounds which possess antioxidant and redox regulatory properties and are a source of H₂S which can support mitochondrial bioenergetics.

Cocaine elicits autophagic cytotoxicity via a nitric oxide-GAPDH signaling cascade

Cocaine exerts its behavioral stimulant effects by facilitating synaptic actions of neurotransmitters such as dopamine and serotonin. It is also neurotoxic and broadly cytotoxic, leading to overdose deaths. We demonstrate that the cytotoxic actions of cocaine reflect selective enhancement of autophagy, a process that physiologically degrades metabolites and cellular organelles, and that uncontrolled autophagy can also lead to cell death. In brain cultures, cocaine markedly increases levels of LC3-II and depletes p62, both actions characteristic of autophagy. By contrast, cocaine fails to stimulate cell death processes reflecting parthanatos, monitored by cleavage of poly(ADP ribose)polymerase-1 (PARP-1), or necroptosis, assessed by levels of phosphorylated mixed lineage kinase domain-like protein. Pharmacologic inhibition of autophagy protects neurons against cocaine-induced cell death. On the other hand, inhibition of parthanatos, necroptosis, or apoptosis did not change cocaine cytotoxicity. Depletion of ATG5 or beclin-1, major mediators of autophagy, prevents cocaine-induced cell death. By contrast, depleting caspase-3, whose cleavage reflects apoptosis, fails to alter cocaine cytotoxicity, and cocaine does not alter caspase-3 cleavage. Moreover, depleting PARP-1 or RIPK1, key mediators of parthanatos and necroptosis, respectively, did not prevent cocaine-induced cell death. Autophagic actions of cocaine are mediated by the nitric oxide-glyceraldehyde-3-phosphate dehydrogenase signaling pathway. Thus, cocaine-associated autophagy is abolished by depleting GAPDH via shRNA; by the drug CGP3466B, which prevents GAPDH nitrosylation; and by mutating cysteine-150 of GAPDH, its site of nitrosylation. Treatments that selectively influence cocaine-associated autophagy may afford therapeutic benefit.

Cocaine Constrictor Mechanisms of the Cerebral Vasculature

Cocaine constriction of the cerebral vasculature is thought to contribute to the ischemia associated with cocaine use. However, the mechanisms whereby cocaine elicits relevant vasoconstriction remain elusive. Indeed, proposed intra- and intercellular mechanisms based on over 3 decades of ex vivo vascular studies are, for the most part, of questionable relevancy due to the generally low contractile efficacy of cocaine combined with the use of nonresistance-type vessels. Furthermore, the significance attached to mechanisms derived from in vivo animal studies may be limited by the inability to demonstrate cocaine-induced decreased cerebral blood flow, as observed in (awake) humans. Despite these apparent limitations, we surmise that the vasoconstriction relevant to cocaine-induced ischemia is elicited by inhibition of dilator and activation of constrictor pathways because of cocaine action on the neurovascular unit (neuron, astrocyte, and vessel) and on vessels outside the unit. Furthermore, previous cocaine exposure, that is, conditions present in human subjects, downregulates and sensitizes these dilator and constrictor pathways, respectively, thereby enhancing constriction to acute cocaine. Identification of specific intra- and intercellular mechanisms requires investigations in the isolated microvasculature and the neurovascular unit from species chronically exposed to cocaine and in which cocaine decreases cerebral blood flow.

Psychostimulant-Induced Testicular Toxicity in Mice: Evidence of Cocaine and Caffeine Effects on the Local Dopaminergic System

Several organ systems can be affected by psychostimulant toxicity. However, there is not sufficient evidence about the impact of psychostimulant intake on testicular physiology and catecholaminergic systems. The aim of the present study was to further explore potential toxic consequences of chronic exposure to cocaine, caffeine, and their combination on testicular physiology. Mice were injected with a 13-day chronic binge regimen of caffeine (3x5mg/kg), cocaine (3×10mg/kg), or combined administration. Mice treated with cocaine alone or combined with caffeine showed reduced volume of the seminiferous tubule associated to a reduction in the number of spermatogonia. Cocaine-only and combined treatments induced increased lipid peroxidation evaluated by TBARS assay and decreased glutathione peroxidase mRNA expression. Importantly, caffeine-cocaine combination potentiated the cocaine-induced germ cell loss, and induced pro-apoptotic BAX protein expression and diminished adenosine receptor A1 mRNA levels. We analyzed markers of dopaminergic function in the testis and detected the presence of tyrosine hydroxylase (TH) in the cytoplasm of androgen-producing Leydig cells, but also in meiotic germs cells within seminiferous tubules. Moreover, using transgenic BAC-Drd1a-tdTomato and D2R-eGFP mice, we report for the first time the presence of dopamine receptors (DRs) D1 and D2 in testicular mouse Leydig cells. Interestingly, the presence of DRD1 was also detected in the spermatogonia nearest the basal lamina of the seminiferous tubules, which did not show TH staining. We observed that psychostimulants induced downregulation of DRs mRNA expression and upregulation of TH protein expression in the testis. These findings suggest a potential role of the local dopaminergic system in psychostimulant-induced testicular pathology.

Delirium Tremens Leads to Poor Outcomes for Acute Coronary Syndrome

OBJECTIVES

The mortality rate for patients with delirium tremens (DT) is 5%. As these patients present with elevated cardiac indices, coexisting DT in acute coronary syndrome (ACS) likely worsens outcomes. Our aim was to examine the outcomes of alcohol withdrawal syndrome (AWS) and DT in patients with ACS.

METHODS

We used the Nationwide Inpatient Sample (2000-2009) for our study. A multivariable logistic regression model was used to examine the independent association of AWS on inhospital mortality and a multivariable linear regression was used to examine the effect of AWS on inpatient length of stay (LOS).

RESULTS

An estimated 2,465,852 admissions with a primary diagnosis of ACS were analyzed. Of these, 4,499 patients had AWS and 3,460 patients had DT. Adjusting for age, gender, race, insurance, hospital characteristics, Charlson's comorbidity index, stent placement and year, the inhospital mortality was significant only for DT (OR 1.56; 95% CI 1.21-2.04). Inpatient LOS was 1.64 (95% CI 1.58-1.73) times higher in those with AWS and 2.33 (95% CI 2.22-2.43) times higher in DT when compared to nonalcoholics. Total hospital charges were higher for patients with AWS and DT when compared to nonalcoholics.

CONCLUSIONS

Coexisting DT in ACS admissions is associated with increased mortality along with longer inpatient LOS and higher hospital costs.

Cocaine modulates HIV-1 integration in primary CD4+ T cells: implications in HIV-1 pathogenesis in drug-abusing patients

Epidemiologic studies suggest that cocaine abuse worsens HIV-1 disease progression. Increased viral load has been suggested to play a key role for the accelerated HIV disease among cocaine-abusing patients. The goal of this study was to investigate whether cocaine enhances proviral DNA integration as a mechanism to increase viral load. We infected CD4(+) T cells that are the primary targets of HIV-1 in vivo and treated the cells with physiologically relevant concentrations of cocaine (1 µM-100 µM). Proviral DNA integration in the host genome was measured by nested qPCR. Our results illustrated that cocaine from 1 µM through 50 µM increased HIV-1 integration in CD4(+) T cells in a dose-dependent manner. As integration can be modulated by several early postentry steps of HIV-1 infection, we examined the direct effects of cocaine on viral integration by in vitro integration assays by use of HIV-1 PICs. Our data illustrated that cocaine directly increases viral DNA integration. Furthermore, our MS analysis showed that cocaine is able to enter CD4(+) T cells and localize to the nucleus-. In summary, our data provide strong evidence that cocaine can increase HIV-1 integration in CD4(+) T cells. Therefore, we hypothesize that increased HIV-1 integration is a novel mechanism by which cocaine enhances viral load and worsens disease progression in drug-abusing HIV-1 patients.

Toxic effects of xylazine on endothelial cells in combination with cocaine and 6-monoacetylmorphine

The use of xylazine as a drug of abuse has emerged worldwide in the last 7 years, including Puerto Rico. Clinical findings reported that xylazine users present greater physiological deterioration, than heroin users. The aim of this study was to assess the xylazine toxicity on endothelial cells, as this is one of the first tissues impact upon administration. Human umbilical vein endothelial cells in culture were treated with xylazine, cocaine, 6-monoacetylmorphine (heroin metabolite) and its combinations, at concentrations of 0.10-400 μM, for periods of 24, 48 and 72 h. IC50 were calculated and the Annexin V assay implemented to determine the cell death mechanism. Results indicated IC50 values at 24h as follow: xylazine 62 μM, cocaine 210 μM, 6-monoacetylmorphine 300 μM. When these drugs were combined the IC50 value was 57 μM. Annexin V results indicated cell death by an apoptosis mechanism in cells treated with xylazine or in combination. Results demonstrated that xylazine use inhibits the endothelial cell proliferation, at lower concentrations than cocaine and 6-monoacetylmorphine. These findings contribute to the understanding of the toxicity mechanisms induced by xylazine on endothelial cells.

A selective sigma-2 receptor ligand antagonizes cocaine-induced hyperlocomotion in mice

Cocaine functions, in part, through agonist actions at sigma-1 (σ1 ) receptors, while roles played by sigma-2 (σ2 ) receptors are less established. Attempts to discriminate σ2 receptor-mediated effects of cocaine in locomotor hyperactivity assays have been hampered by the lack of potent and selective antagonists. Certain tetrahydroisoquinolinyl benzamides display high σ2 receptor affinity, and excellent selectivity for binding to σ2 over σ1 receptors. The behavioral properties of this structural class of σ ligands have not yet been investigated. The present study evaluated 5-bromo-N-[4-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-butyl)]-2,3-dimethoxy-benzamide, 1, a ligand shown by others to bind preferentially to σ2 over σ1 receptors, as well as dopamine D2 and D3 sites. First, we determined binding to monoamine transporters and opioid receptors, and noted 57-fold selectivity for σ2 receptors over the serotonin transporter, and >800-fold selectivity for σ2 receptors over the other sites tested. We then examined 1 in locomotor activity studies using male CD-1® mice, and saw no alteration of basal activity at doses up to 31.6 µmol/kg. Cocaine produced a fivefold increase in locomotor activity, which was attenuated by 66% upon pretreatment of mice with 1 at 31.6 µmol/kg. In vivo radioligand binding studies also were performed, and showed no occupancy of σ1 receptors or the dopamine transporter by 1, or its possible metabolites, at the 31.6 µmol/kg dose. Thus, ligand 1 profiles behaviorally as a σ2 receptor-selective antagonist that is able to counteract cocaine's motor stimulatory effects.

Cocaine enhances HIV-1-induced CD4(+) T-cell apoptosis: implications in disease progression in cocaine-abusing HIV-1 patients

Substance abuse is a major barrier in eradication of the HIV epidemic because it serves as a powerful cofactor for viral transmission, disease progression, and AIDS-related mortality. Cocaine, one of the commonly abused drugs among HIV-1 patients, has been suggested to accelerate HIV disease progression. However, the underlying mechanism remains largely unknown. Therefore, we tested whether cocaine augments HIV-1-associated CD4(+) T-cell decline, a predictor of HIV disease progression. We examined apoptosis of resting CD4(+) T cells from HIV-1-negative and HIV-1-positive donors in our study, because decline of uninfected cells plays a major role in HIV-1 disease progression. Treatment of resting CD4(+) T cells with cocaine (up to 100 μmol/L concentrations) did not induce apoptosis, but 200 to 1000 μmol/L cocaine induced apoptosis in a dose-dependent manner. Notably, treatment of CD4(+) T cells isolated from healthy donors with both HIV-1 virions and cocaine significantly increased apoptosis compared with the apoptosis induced by cocaine or virions alone. Most important, our biochemical data suggest that cocaine induces CD4(+) T-cell apoptosis by increasing intracellular reactive oxygen species levels and inducing mitochondrial depolarization. Collectively, our results provide evidence of a synergy between cocaine and HIV-1 on CD4(+) T-cell apoptosis that may, in part, explain the accelerated disease observed in HIV-1-infected drug abusers.