Cardiovascular and Hepatic Toxicity of Cocaine: Potential Beneficial Effects of Modulators of Oxidative Stress

Liver disorders in substance abusers

Substance use disorders are a global health problem with detrimental effects on one's health, wealth, and stealth. It includes the use of prescribed medications or the use of illicit drugs in excess amounts or for excess durations associated with complex neuropsychiatric and/or physical manifestations. It affects every organ in the body, and the liver is no exception to the deleterious effects of substance abuse. The mechanism of liver injury varies from agent to agent and may include direct toxic effects, oxidative stress, and inflammatory responses. The hepatic involvement ranges from asymptomatic liver enzyme elevation and fatty liver disease to hepatitis, liver failure, and cirrhosis. Alcohol, the most frequent agent implicated in substance use disorder, is also a prototype hepatotoxin, capable of inducing the whole spectrum of liver diseases. Cigarette smoke contains numerous harmful chemicals, including carcinogens, which can induce liver injury, fibrosis, and HCC. Cocaine, particularly in acute overdose, can result in ischemic hepato-necrosis, while it can also result in clinically inapparent transaminasemia. Marijuana and opiates, despite being associated with numerous deleterious effects, are rarely implicated in clinically apparent liver injury. Individuals with substance use disorder are also prone to viral hepatitis and hepatic insults secondary to hypotension, hypoxia, and other systemic ailments. Liver transplant candidacy in individuals with substance use disorder is a highly complex arena, with guidelines balancing abstinence requirements against evolving evidence on outcomes. This review article provides a thorough analysis of the hepatotoxic repercussions stemming from the agents commonly implicated in substance abuse disorders.

Episodic Cocaine Use as a Cause of Venous Thromboembolism and Acute Liver Injury

BACKGROUND Pulmonary embolism secondary to deep vein thrombosis (DVT) with cor pulmonale is commonly associated with risk factors including surgery, cancer, and prolonged immobility. Cocaine is known to cause vasoconstriction and has a prothrombotic effect. Prolonged and heavy use of cocaine can also cause inflammation and liver damage. However, data on its potential role in causing pulmonary embolism and direct hepatotoxicity in cases of episodic use are scarce. CASE REPORT A 34-year-old man with no significant medical history except for episodic cocaine use presented in respiratory distress. Workup revealed submassive pulmonary embolism with pulmonary infarctions complicated by pneumonia, hypoxemic respiratory failure, and anemia. He was treated with anticoagulation and intensive care. On day 5 of hospitalization, the patient had an acute hepatic injury. His alanine aminotransferase level peaked at over 2000 IU/L on day 7, until finally tapering. Liver failure was found to be secondary to cocaine use. Liver enzyme levels improved with supportive care. He was discharged with apixaban and continued liver enzyme monitoring. CONCLUSIONS When investigating the cause of venous thromboembolism and transaminitis, evaluating cocaine use via patient history or laboratory analysis of cocaine and its metabolites should be considered. Cocaine is known to cause vasoconstriction and has a prothrombotic effect, although data on its potential role in causing pulmonary embolism and direct hepatotoxicity in cases of episodic use are scarce. Further investigation, such as cohort studies, could help strengthen our understanding of the relationship between cocaine use, acute hepatic injury, and pulmonary embolism.

Subcellular Effectors of Cocaine Cardiotoxicity: All Roads Lead to Mitochondria-A Systematic Review of the Literature

Cocaine abuse is a serious public health problem as this drug exerts a plethora of functional and histopathological changes that potentially lead to death. Cocaine causes complex multiorgan toxicity, including in the heart where the blockade of the sodium channels causes increased catecholamine levels and alteration in calcium homeostasis, thus inducing an increased oxygen demand. Moreover, there is evidence to suggest that mitochondria alterations play a crucial role in the development of cocaine cardiotoxicity. We performed a systematic review according to the Preferred Reporting Items for Systemic Reviews and Meta-Analysis (PRISMA) scheme to evaluate the mitochondrial mechanisms determining cocaine cardiotoxicity. Among the initial 106 articles from the Pubmed database and the 17 articles identified through citation searching, 14 final relevant studies were extensively reviewed. Thirteen articles included animal models and reported the alteration of specific mitochondria-dependent mechanisms such as reduced energy production, imbalance of membrane potential, increased oxidative stress, and promotion of apoptosis. However, only one study evaluated human cocaine overdose samples and observed the role of cocaine in oxidative stress and the induction of apoptosis though mitochondria. Understanding the complex processes mediated by mitochondria through forensic analysis and experimental models is crucial for identifying potential therapeutic targets to mitigate or reverse cocaine cardiotoxicity in humans.

A Case of Cocaine-Induced Acute Liver Failure Reversed With N-Acetylcysteine

Acute liver failure (ALF) is a life-threatening injury that is most often caused by drug-induced injury, including acetaminophen overdose, in the United States. The hallmarks of ALF are hepatic encephalopathy and coagulopathy in a patient without an established history of liver disease. While acetaminophen overdose has an antidote, that is N-acetylcysteine (NAC), when given acutely, most other causes of hepatic failure require an urgent liver transplant. In this paper, we report a case of cocaine-induced acute liver failure that was reversed with the administration of NAC. Our case began when a middle-aged male presented to the emergency department complaining of nausea, vomiting, fatigue, and confusion for the past three days. His past medical history was pertinent for a history of opioid use disorder and his physical exam was remarkable for somnolence, asterixis, and periumbilical ecchymoses. His initial lab results showed markedly elevated liver function tests, prolonged coagulation studies, and a urine drug screen that was positive for cocaine. During the patient's interview, his vital signs became unstable. He was intubated for airway protection and transferred to a tertiary care facility for liver transplant evaluation with the diagnosis of cocaine-induced acute liver failure. There he received NAC, lactulose, rifaximin, and vasopressors. On day two of treatment, his clinical condition greatly improved, and he was extubated. He continued to receive NAC until day five when his liver function tests and coagulopathy improved enough to stop treatment. This case report highlights the clinical benefit of NAC in a case of cocaine-induced acute liver failure, improving the patient's survival and eliminating his need for a liver transplant.

Morphologic Markers of Acute and Chronic Stress in Child Abuse

OBJECTIVES

To elucidate pathologic markers of acute and chronic stress found but rarely reported in chronic child abuse.

METHODS

Autopsies of 3 cases of fatal child abuse with well-documented chronic maltreatment are reported, with an emphasis on the nontraumatic findings of acute and chronic stress.

RESULTS

Besides the overwhelming physical injuries, all 3 children and 1 additional case obtained for consultation had telogen effluvium, a form of alopecia well known to be associated with stress in adults and some children but never reported in chronic abuse. All 3 had the microscopic findings of markedly involuted thymus, a well-known marker of physiologic stress in children but only occasionally referred to in child abuse. All 3 also had microscopic findings of myocardial necrosis associated with supraphysiologic levels of catecholamine, a well-documented finding associated with stress but rarely reported in fatalities associated with child abuse. Two of the 3 children also had Anitschkow-like nuclear changes in cardiac tissue, markers associated with prior, nonischemic myocardial pathologies that may be associated with prior episodes of acute stress.

CONCLUSIONS

Pathologists are urged to explore these markers as supportive evidence in their own investigations of possible child abuse fatalities, especially when associated with stress.

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.

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.

Substance Use Disorder in the COVID-19 Pandemic: A Systematic Review of Vulnerabilities and Complications

As the world endures the coronavirus disease 2019 (COVID-19) pandemic, the conditions of 35 million vulnerable individuals struggling with substance use disorders (SUDs) worldwide have not received sufficient attention for their special health and medical needs. Many of these individuals are complicated by underlying health conditions, such as cardiovascular and lung diseases and undermined immune systems. During the pandemic, access to the healthcare systems and support groups is greatly diminished. Current research on COVID-19 has not addressed the unique challenges facing individuals with SUDs, including the heightened vulnerability and susceptibility to the disease. In this systematic review, we will discuss the pathogenesis and pathology of COVID-19, and highlight potential risk factors and complications to these individuals. We will also provide insights and considerations for COVID-19 treatment and prevention in patients with SUDs.

Acute and Chronic Effects of Cocaine on Cardiovascular Health

Cardiac complications resulting from cocaine use have been extensively studied because of the complicated pathophysiological mechanisms. This study aims to review the underlying cellular and molecular mechanisms of acute and chronic effects of cocaine on the cardiovascular system with a specific focus on human studies. Studies have consistently reported the acute effects of cocaine on the heart (e.g., electrocardiographic abnormalities, acute hypertension, arrhythmia, and acute myocardial infarction) through multifactorial mechanisms. However, variable results have been reported for the chronic effects of cocaine. Some studies found no association of cocaine use with coronary artery disease (CAD), while others reported its association with subclinical coronary atherosclerosis. These inconsistent findings might be due to the heterogeneity of study subjects with regard to cardiac risk. After cocaine use, populations at high risk for CAD experienced coronary atherosclerosis whereas those at low risk did not experience CAD, suggesting that the chronic effects of cocaine were more likely to be prominent among individuals with higher CAD risk. Studies also suggested that risky behaviors and cardiovascular risks may affect the association between cocaine use and mortality. Our study findings highlight the need for education regarding the deleterious effects of cocaine, and access to interventions for cocaine abusers.

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.

Hepatoprotective effect of N-acetylcysteine in trabectedin-induced liver toxicity in patients with advanced soft tissue sarcoma

PURPOSE

Trabectedin is one of the few active agents in soft tissue sarcoma (STS) but hepatotoxicity is frequent and represents a dose-limiting factor. Protective strategies aiming at counteracting this important side effect have a crucial clinical impact. Due to its antioxidant properties, N-acetylcysteine (NAC) has a recognized hepatoprotective effect and this provides the rationale for testing NAC in the management of trabectedin-induced hepatotoxicity.

METHODS

Patients with recurrent or metastatic soft tissue sarcoma, consecutively observed at our institution, who were considered eligible to trabectedin, received concomitant NAC if they had impaired hepatic or renal function at baseline or developed hepatotoxicity during treatment. The study aim was to retrospectively explore trabectedin administration in terms of number of cycles, mean dose, and dose intensity (DI) in patients who received NAC as compared with those who did not. Secondary end points were progression-free survival (PFS) and overall survival (OS).

RESULTS

A total number of 18 patients were enrolled in this study. Nine received NAC and nine did not. The median number of administered trabectedin cycles, mean trabectedin dose/cycles, and median DI was comparable in the two groups (p = 0.450, p = 0.534, and p = 0.450, respectively). The PFS and OS curves overlapped.

CONCLUSION

This explorative study suggests that NAC can have a hepatoprotective activity in patients receiving trabectedin allowing to maintain an adequate dose intensity and continuative administration in patients with impaired liver and renal function or developing treatment-induced hepatotoxicity. A prospective randomized trial is warranted.

Chronic treatment with Tempol during acquisition or withdrawal from CPP abolishes the expression of cocaine reward and diminishes oxidative damage

In previous studies, we reported that pretreatment with the antioxidant Tempol attenuated the development and expression of cocaine-induced psychomotor sensitization in rats and diminished cocaine-induced oxidative stress (OS) in the prefrontal cortex (PFC) and nucleus accumbens (NAc), suggesting a potential role for Tempol in interfering with cocaine-related psychomotor sensitization. The aim of the current study was to examine the role of Tempol in reward and reinforcement using the conditioned place preference (CPP) paradigm. We found that administration of Tempol during the conditioning session abolished the expression of cocaine-induced CPP. We also found that OS was significantly elevated following the establishment of CPP, and that cocaine-induced OS was significantly diminished by pretreatment with Tempol during conditioning. Furthermore, we found that repeated, but not single, administration of Tempol for seven days during withdrawal from CPP resulted in significant attenuation in the expression of CPP. Moreover, Tempol did not affect the expression of food reward. Taken together, these findings provide evidence for the involvement of Tempol in regulating cocaine rewarding properties without affecting natural rewards. Since Tempol was found to be effective in reducing OS and expression of CPP following withdrawal, it may be a potential treatment for cocaine addiction.

Sex-dependent mental illnesses and mitochondria

The prevalence of some mental illnesses, including major depression, anxiety-, trauma-, and stress-related disorders, some substance use disorders, and later onset of schizophrenia, is higher in women than men. While the higher prevalence in women could simply be explained by socioeconomic determinants, such as income, social status, or cultural background, extensive studies show sex differences in biological, pharmacokinetic, and pharmacological factors contribute to females' vulnerability to these mental illnesses. In this review, we focus on estrogens, chronic stress, and neurotoxicity from behavioral, pharmacological, biological, and molecular perspectives to delineate the sex differences in these mental illnesses. Particularly, we investigate a possible role of mitochondrial function, including biosynthesis, bioenergetics, and signaling, on mediating the sex differences in psychiatric disorders.

Redox theory of aging: implications for health and disease

Genetics ultimately defines an individual, yet the phenotype of an adult is extensively determined by the sequence of lifelong exposures, termed the exposome. The redox theory of aging recognizes that animals evolved within an oxygen-rich environment, which created a critical redox interface between an organism and its environment. Advances in redox biology show that redox elements are present throughout metabolic and structural systems and operate as functional networks to support the genome in adaptation to environmental resources and challenges during lifespan. These principles emphasize that physical and functional phenotypes of an adult are determined by gene-environment interactions from early life onward. The principles highlight the critical nature of cumulative exposure memories in defining changes in resilience progressively during life. Both plasma glutathione and cysteine systems become oxidized with aging, and the recent finding that cystine to glutathione ratio in human plasma predicts death in coronary artery disease (CAD) patients suggests this could provide a way to measure resilience of redox networks in aging and disease. The emerging concepts of cumulative gene-environment interactions warrant focused efforts to elucidate central mechanisms by which exposure memory governs health and etiology, onset and progression of disease.

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.