Efavirenz exposure, alone and in combination with known drugs of abuse, engenders addictive-like bio-behavioural changes in rats

The Impact of Drugs and Substance Abuse on Viral Pathogenesis-A South African Perspective

Illicit drug and alcohol abuse have significant negative consequences for individuals who inject drugs/use drugs (PWID/UDs), including decreased immune system function and increased viral pathogenesis. PWID/UDs are at high risk of contracting or transmitting viral illnesses such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). In South Africa, a dangerous drug-taking method known as "Bluetoothing" has emerged among nyaope users, whereby the users of this drug, after injecting, withdraw blood from their veins and then reinject it into another user. Hence, the transmission of blood-borne viruses (BBVs) is exacerbated by this "Bluetooth" practice among nyaope users. Moreover, several substances of abuse promote HIV, HBV, and HCV replication. With a specific focus on the nyaope drug, viral replication, and transmission, we address the important influence of abused addictive substances and polysubstance use in this review.

Exploring the perspectives of community members on use of Nyaope in Tshwane, South Africa

BACKGROUND

 Substance use is a major public health issue in South Africa. Cocktails, containing two or more low-quality substances, have been reported. Nyaope is one of the most popular and is widely available. It has a significant impact on users and communities. The aim of this study was to explore community members' perceptions of the potential contributors to Nyaope use and dependency.

METHODS

 This was an exploratory descriptive qualitative study that conducted three focus group interviews with 29 community members. A maximum variation sample was used. Data were analysed using the framework method, assisted by Atlas-ti.

RESULTS

 Seven main themes were identified, namely unfavourable home environments, distrust between community members and the local police, easy access to Nyaope at school, inadequate social services, lack of religious or spiritual drive, unfavourable community environments and the effects of Nyaope on users.

CONCLUSION

 The factors identified, were used to construct an emerging model of how Nyaope use is driven in Tshwane. It is clear that a multisectoral response is required involving health and social services, basic education, policing and community leadership. Further research will explore the views of family members and users and quantify the importance of the factors identified.Contribution: This study showed that rather than a simple linear chain of events, Nyaope use is enabled by a complex system of interconnected elements. According to the respondents, variables in the community at large, the school, the home and the specific user all have a role in Nyaope usage and dependency.

HIV and Drug Use: A Tale of Synergy in Pulmonary Vascular Disease Development

Over the past two decades, with the advent and adoption of highly active anti-retroviral therapy, HIV-1 infection, a once fatal and acute illness, has transformed into a chronic disease with people living with HIV (PWH) experiencing increased rates of cardio-pulmonary vascular diseases including life-threatening pulmonary hypertension. Moreover, the chronic consequences of tobacco, alcohol, and drug use are increasingly seen in older PWH. Drug use, specifically, can have pathologic effects on the cardiovascular health of these individuals. The "double hit" of drug use and HIV may increase the risk of HIV-associated pulmonary arterial hypertension (HIV-PAH) and potentiate right heart failure in this population. This article explores the epidemiology and pathophysiology of PAH associated with HIV and recreational drug use and describes the proposed mechanisms by which HIV and drug use, together, can cause pulmonary vascular remodeling and cardiopulmonary hemodynamic compromise. In addition to detailing the proposed cellular and signaling pathways involved in the development of PAH, this article proposes areas ripe for future research, including the influence of gut dysbiosis and cellular senescence on the pathobiology of HIV-PAH. © 2023 American Physiological Society. Compr Physiol 13:4659-4683, 2023.

Prolonged efavirenz exposure reduces peripheral oxytocin and vasopressin comparable to known drugs of addiction in male Sprague Dawley rats

INTRODUCTION

Several drugs of abuse (DOA) are capable of modulating neurohypophysial hormones, such as oxytocin (OT) and vasopressin (VP), potentially resulting in the development of psychological abnormalities, such as cognitive dysfunction, psychoses, and affective disorders. Efavirenz (EFV), widely used in Africa and globally to treat HIV, induces diverse neuropsychiatric side effects while its abuse has become a global concern. The actions of EFV may involve neurohypophysial system (NS) disruption like that of known DOA. This study investigated whether sub-chronic EFV exposure, at a previously-determined rewarding dose, alters peripheral OT and VP levels versus that of a control, ∆9-tetrahydrocannabinol (∆9-THC), methamphetamine (MA) and cocaine.

MATERIALS AND METHODS

To simulate the conditions under which reward-driven behavior had previously been established for EFV, male Sprague Dawley rats (n = 16/exposure) received intraperitoneal vehicle (control) or drug administration across an alternating sixteen-day dosing protocol. Control administration (saline/olive oil; 0.2 ml) occurred on odd-numbered and drug administration (EFV: 5 mg/kg, ∆9-THC: 0.75 mg/kg, MA: 1 mg/kg, or cocaine: 20 mg/kg) on even-numbered days followed by euthanasia, trunk blood collection and plasma extraction for neuropeptide assay. Effect of drug exposure on peripheral OT and VP levels was assessed versus controls and quantified using specific ELISA kits. Statistical significance was determined by Kruskal-Wallis ANOVA, with p < 0.05. Ethics approval: NWU-00291-17-A5.

RESULTS

Delta-9-THC reduced OT and VP plasma levels (p < 0.0001, p = 0.0141; respectively), cocaine reduced plasma OT (p = 0.0023), while MA reduced plasma VP levels (p = 0.0001), all versus control. EFV reduced OT and VP plasma levels (p < 0.0001; OT and VP) versus control, and similar to ∆9-THC.

CONCLUSION

EFV markedly affects the NS in significantly reducing both plasma OT and VP equivalent to DOA. Importantly, EFV has distinct effects on peripheral OT and VP levels when assessed within the context of drug dependence. The data highlights a possible new mechanism underlying previously documented EFV-induced effects in rats, and whereby EFV may induce neuropsychiatric adverse effects clinically; also providing a deeper understanding of the suggested abuse-potential of EFV.

HIV-Associated Apathy/Depression and Neurocognitive Impairments Reflect Persistent Dopamine Deficits

Individuals living with human immunodeficiency virus type 1 (HIV-1) are often plagued by debilitating neurocognitive impairments and affective alterations;the pathophysiology underlying these deficits likely includes dopaminergic system dysfunction. The present review utilized four interrelated aims to critically examine the evidence for dopaminergic alterations following HIV-1 viral protein exposure. First, basal dopamine (DA) values are dependent upon both brain region andexperimental approach (i.e., high-performance liquid chromatography, microdialysis or fast-scan cyclic voltammetry). Second, neurochemical measurements overwhelmingly support decreased DA concentrations following chronic HIV-1 viral protein exposure. Neurocognitive impairments, including alterations in pre-attentive processes and attention, as well as apathetic behaviors, provide an additional line of evidence for dopaminergic deficits in HIV-1. Third, to date, there is no compelling evidence that combination antiretroviral therapy (cART), the primary treatment regimen for HIV-1 seropositive individuals, has any direct pharmacological action on the dopaminergic system. Fourth, the infection of microglia by HIV-1 viral proteins may mechanistically underlie the dopamine deficit observed following chronic HIV-1 viral protein exposure. An inclusive and critical evaluation of the literature, therefore, supports the fundamental conclusion that long-term HIV-1 viral protein exposure leads to a decreased dopaminergic state, which continues to persist despite the advent of cART. Thus, effective treatment of HIV-1-associated apathy/depression and neurocognitive impairments must focus on strategies for rectifying decreases in dopamine function.

Perinatal exposure of rats to the HIV drug efavirenz affects medial prefrontal cortex cytoarchitecture

Efavirenz (EFV) is used for antiretroviral treatment of HIV infection, and successfully inhibits viral replication and mother-to-child transmission of HIV during pregnancy and childbirth. Unfortunately, the drug induces neuropsychiatric symptoms such as anxiety and depressed mood and potentially affects cognitive performance. EFV acts on, among others, the serotonin transporter and serotonin receptors that are expressed in the developing brain. Yet, how perinatal EFV exposure affects brain cytoarchitecture remains unclear. Here, we exposed pregnant and lactating rats to EFV, and examined in the medial prefrontal cortex (mPFC) of their adult offspring the effects of the maternal EFV exposure on cortical architecture. We observed a significant decrease in the number of cells, mainly mature neurons, in the infra/prelimbic and cingulate cortices of adult offspring. Next, we found an altered cortical cytoarchitecture characterized by a significant reduction in deep- and superficial-layer cells. This was accompanied by a sharp increase in programmed cell death, as we identified a significantly higher number of cleaved Caspase-3-positive cells. Finally, the serotonergic and dopaminergic innervation of the mPFC subdomains was increased. Thus, the perinatal exposure to EFV provoked in the mPFC of adult offspring cell death, significant changes in cytoarchitecture, and disturbances in serotonergic and dopaminergic innervation. Our results are important in the light of EFV treatment of HIV-positive pregnant women, and its effect on brain development and cognitive behavior.

Bidirectional Associations among Nicotine and Tobacco Smoke, NeuroHIV, and Antiretroviral Therapy

People living with HIV (PLWH) in the antiretroviral therapy (ART) era may lose more life-years to tobacco use than to HIV. Yet, smoking rates are more than twice as high among PLWH than the general population, contributing not just to mortality but to other adverse health outcomes, including neurocognitive deficits (neuroHIV). There is growing evidence that synergy with chronic inflammation and immune dysregulation that persists despite ART may be one mechanism by which tobacco smoking contributes to neuroHIV. This review will summarize the differential effects of nicotine vs tobacco smoking on inflammation in addition to the effects of tobacco smoke components on HIV disease progression. We will also discuss biomarkers of inflammation via neuroimaging as well as biomarkers of nicotine dependence (e.g., nicotine metabolite ratio). Tobacco smoking and nicotine may impact ART drug metabolism and conversely, certain ARTs may impact nicotine metabolism. Thus, we will review these bidirectional relationships and how they may contribute to neuroHIV and other adverse outcomes. We will also discuss the effects of tobacco use on the interaction between peripheral organs (lungs, heart, kidney) and subsequent CNS function in the context of HIV. Lastly, given the dramatic rise in the use of electronic nicotine delivery systems, we will discuss the implications of vaping on these processes. Despite the growing recognition of the importance of addressing tobacco use among PLWH, more research is necessary at both the preclinical and clinical level to disentangle the potentially synergistic effects of tobacco use, nicotine, HIV, cognition and immune dysregulation, as well as identify optimal approaches to reduce tobacco use. Graphical Abstract Proposed model of the relationships among HIV, ART, smoking, inflammation, and neurocognition. Solid lines represent relationships supported by evidence. Dashed lines represent relationships for which there is not enough evidence to make a conclusion. (a) HIV infection produces elevated levels of inflammation even among virally suppressed individuals. (b) HIV is associated with deficits in cognition function. (c) Smoking rates are higher among PLWH, compared to the general population. (d) The nicotine metabolite ratio (NMR) is associated with smoking behavior. (e) HIV and tobacco use are both associated with higher rates of psychiatric comorbidities, such as depression, and elevated levels of chronic stress. These factors may represent other mechanisms linking HIV and tobacco use. (f) The relationship between nicotine, tobacco smoking, and inflammation is complex, but it is well-established that smoking induces inflammation; the evidence for nicotine as anti-inflammatory is supported in some studies, but not others. (g) The relationship between tobacco use and neurocognition may differ for the effects of nicotine (acute nicotine use may have beneficial effects) vs. tobacco smoking (chronic use may impair cognition). (h) Elevated levels of inflammation may be associated with deficits in cognition. (i) PLWH may metabolize nicotine faster than those without HIV; the mechanism is not yet known and the finding needs validation in larger samples. We also hypothesize that if HIV-infection increases nicotine metabolism, then we should observe an attenuation effect once ART is initiated. (j) It is possible that the increase in NMR is due to ART effects on CYP2A6. (k) We hypothesize that faster nicotine metabolism may result in higher levels of inflammation since nicotine has anti-inflammatory properties.

Recreational ART use among individuals living with HIV/AIDS in South Africa: Examining longitudinal ART initiation and viral suppression

BACKGROUND

South Africa has the highest number of people living with HIV (PLWH) and one of the largest antiretroviral therapy (ART) programs globally. High rates of substance use comorbidity exist, including speculation of recreational ART use (i.e., mixing ART with other illicit drugs). Recreational ART use may affect viral load among PLWH due to ART nonadherence and/or viral resistance; however, prior quantitative research has not examined rates of recreational ART use, nor associations with HIV treatment outcomes longitudinally.

METHODS

Data were drawn from a prospective, observational cohort study (n = 500) of ART-eligible adults recruited from two HIV voluntary counseling and testing centers in Cape Town, and Johannesburg, South Africa. Multiple logistic regression models assessed recreational ART use as a predictor of ART initiation over six months and viral load suppression over nine months, above and beyond other substance use (binge drinking and illicit drug use).

RESULTS

Approximately 5% (n = 24) reported recreational ART use, which was less frequent in Cape Town compared to Johannesburg (AOR = 0.025; 95%CI: 0.003-0.19; p < 0.001). Recreational ART use was not significantly associated with ART initiation or viral suppression. Other substance use, but not recreational ART use, was significantly associated with lower odds of ART initiation (AOR = 0.54; 95%CI: 0.33-0.87; p = .01) and viral suppression (AOR = 0.47; 95%CI: 0.25-0.89; p = .02).

CONCLUSIONS

Recreational ART use was infrequent and not uniquely associated with ART initiation or viral suppression. Findings suggest that comorbid use of other substances is ultimately what may make recreational ART use problematic for ongoing engagement in care and viral suppression.

Neurodevelopmental and behavioral consequences of perinatal exposure to the HIV drug efavirenz in a rodent model

Efavirenz is recommended as a preferred first-line drug for women of childbearing potential living with human immunodeficiency virus. Efavirenz is known for its central nervous system side effects, which are partly mediated by serotonergic actions. The neurotransmitter serotonin exerts neurotrophic effects during neurodevelopment and antenatal exposure to serotonergic agents has been linked to developmental delay. Although the teratogenic risks of efavirenz appear to be minimal, data on long-term developmental effects remain scarce. Here, we aimed to investigate the short- and long-term behavioral and neurodevelopmental effects of perinatal efavirenz exposure. We treated pregnant rats from gestation day 1 until postnatal day 7 with efavirenz (100 mg/kg) or vehicle. We measured behavioral outcomes in male offspring during the first 3 postnatal weeks, adolescence and adulthood, and conducted brain immunohistochemistry analyses after sacrifice. Perinatal efavirenz exposure resulted in reduced body weight and delayed reflex and motor development. During adulthood, we observed a decrease in the total number of cells and mature neurons in the motor cortex, as well as an increase in the number of Caspase-3-positive cells and serotonergic fibers. Together, our data show a developmental delay and persistent changes in the brain motor cortex of rats exposed to efavirenz perinatally. Because over 1 million children born annually are exposed to antiretroviral therapy, our findings underline the need for clinical studies on long-term neurodevelopmental outcomes of perinatal exposure to efavirenz.