Combined effects of HIV and marijuana use on neurocognitive functioning and immune status

Changes in Immune-Related Biomarkers and Endocannabinoids as a Function of Frequency of Cannabis Use in People Living With and Without HIV

Background: Cannabis use is common among people living with HIV (PLWH). Some observational studies of PLWH have linked cannabis use to lower immune markers; however, this is yet to be confirmed. In addition, whether HIV affects the endogenous cannabinoid system has not been studied. Our objective was to examine changes in immune-related biomarkers and endocannabinoids as a function of cannabis use frequency in people living with and without HIV. Materials and Methods: Data were obtained from a longitudinal study of men who have sex with men living in Los Angeles with, or at risk for, HIV. By design, half were PLWH. Those eligible for the parent study were willing and able to return for follow-up every 6 months. Those eligible for inclusion in this study reported varying levels of current cannabis use at follow-up. Specifically, one visit corresponded to a period of daily use and another to a period of infrequent use (weekly, monthly, or less than monthly). Banked serum from all eligible participants was analyzed for immune-related biomarkers, endocannabinoids, and paracannabinoids. Results: The analysis included 36 men, 19 of whom were PLWH. PLWH reported greater lifetime methamphetamine or amphetamine use (68% vs. 0%) and current cigarette use (55% vs. 20%) than people without HIV. Serum levels of HIV-related immune biomarkers including tumor necrosis factor receptor 2 (TNFR2; p=0.013) and CD27 (p=0.004) were greater in PLWH, alongside lower anandamide (AEA) (F1,34=5.337, p=0.027) and oleoylethanolamide (OEA) (F1,34=8.222, p=0.007) levels relative to people without HIV. Frequency of cannabis use did not impact the serum analytes in our study. Conclusions: Higher levels of TNFR2 and CD27 and lower levels of AEA and OEA in PLWH underscore the role of the TNF/TNFR superfamily in HIV, while highlighting a new role for the enzymatic activity of fatty acid amide hydrolase (the enzyme that hydrolyzes AEA and OEA) in HIV. Findings that cannabis frequency did not impact the immune phenotype may not generalize to other populations of PLWH. Additional work is required to further clarify the relationship between immune markers and endocannabinoids as a function of cannabis use frequency in PLWH. ClinicalTrials.gov ID: NCT01201083.

The Impact of Cannabis Use on Cognition in People with HIV: Evidence of Function-Dependent Effects and Mechanisms from Clinical and Preclinical Studies

PURPOSE OF REVIEW

Cannabis may have beneficial anti-inflammatory effects in people with HIV (PWH); however, given this population's high burden of persisting neurocognitive impairment (NCI), clinicians are concerned they may be particularly vulnerable to the deleterious effects of cannabis on cognition. Here, we present a systematic scoping review of clinical and preclinical studies evaluating the effects of cannabinoid exposure on cognition in HIV.

RECENT FINDINGS

Results revealed little evidence to support a harmful impact of cannabis use on cognition in HIV, with few eligible preclinical data existing. Furthermore, the beneficial/harmful effects of cannabis use observed on cognition were function-dependent and confounded by several factors (e.g., age, frequency of use). Results are discussed alongside potential mechanisms of cannabis effects on cognition in HIV (e.g., anti-inflammatory), and considerations are outlined for screening PWH that may benefit from cannabis interventions. We further highlight the value of accelerating research discoveries in this area by utilizing translatable cross-species tasks to facilitate comparisons across human and animal work.

Effects of acute cannabidiol on behavior and the endocannabinoid system in HIV-1 Tat transgenic female and male mice

Background

Some evidence suggests that cannabidiol (CBD) has potential to help alleviate HIV symptoms due to its antioxidant and anti-inflammatory properties. Here we examined acute CBD effects on various behaviors and the endocannabinoid system in HIV Tat transgenic mice.

Methods

Tat transgenic mice (female/male) were injected with CBD (3, 10, 30 mg/kg) and assessed for antinociception, activity, coordination, anxiety-like behavior, and recognition memory. Brains were taken to quantify endocannabinoids, cannabinoid receptors, and cannabinoid catabolic enzymes. Additionally, CBD and metabolite 7-hydroxy-CBD were quantified in the plasma and cortex.

Results

Tat decreased supraspinal-related nociception and locomotion. CBD and sex had little to no effects on any of the behavioral measures. For the endocannabinoid system male sex was associated with elevated concentration of the proinflammatory metabolite arachidonic acid in various CNS regions, including the cerebellum that also showed higher FAAH expression levels for Tat(+) males. GPR55 expression levels in the striatum and cerebellum were higher for females compared to males. CBD metabolism was altered by sex and Tat expression.

Conclusion

Findings indicate that acute CBD effects are not altered by HIV Tat, and acute CBD has no to minimal effects on behavior and the endocannabinoid system.

Effects of acute Δ9-tetrahydrocannabinol on behavior and the endocannabinoid system in HIV-1 Tat transgenic female and male mice

Cannabis use is highly prevalent especially among people living with HIV (PLWH). Activation of the anti-inflammatory and neuroprotective endocannabinoid system by phytocannabinoids, i.e. Δ9-tetrahydrocannabinol (THC), has been proposed to reduce HIV symptoms. However, THC's effects on HIV-related memory deficits are unclear. Using HIV-1 Tat transgenic mice, the current study investigates acute THC effects on various behavioral outcomes and the endocannabinoid system. For the rodent tetrad model, THC doses (1, 3, 10 mg/kg) induced known antinociceptive effects, with Tat induction increasing antinociceptive THC effects at 3 and 10 mg/kg doses. Only minor or no effects were noted for acute THC on body temperature, locomotor activity, and coordination. Increased anxiety-like behavior was found for females compared to males, but acute THC had no effect on anxiety. Object recognition memory was diminished by acute THC in Tat(-) females but not Tat(+) females, without affecting males. The endocannabinoid system and related lipids were not affected by acute THC, except for THC-induced decreases in CB1R protein expression levels in the spinal cord of Tat(-) mice. Female sex and Tat induction was associated with elevated 2-AG, AEA, AA, CB1R, CB2R, FAAH and/or MAGL expression in various brain regions. Further, AEA levels in the prefrontal cortex of Tat(+) females were negatively associated with object recognition memory. Overall, findings indicate that acute THC exerts differential effects on antinociception and memory, dependent on sex and HIV Tat expression, potentially in relation to an altered endocannabinoid system, which may be of relevance in view of potential cannabis-based treatment options for PLWH.

A longitudinal study of cannabis use and risk for cognitive and functional decline among older adults with HIV

Cannabis use is rapidly increasing among older adults in the United States, in part to treat symptoms of common health conditions (e.g., chronic pain, sleep problems). Longitudinal studies of cannabis use and cognitive decline in aging populations living with chronic disease are lacking. We examined different levels of cannabis use and cognitive and everyday function over time among 297 older adults with HIV (ages 50-84 at baseline). Participants were classified based on average cannabis use: frequent (> weekly) (n = 23), occasional (≤ weekly) (n = 83), and non-cannabis users (n=191) and were followed longitudinally for up to 10 years (average years of follow-up = 3.9). Multi-level models examined the effects of average and recent cannabis use on global cognition, global cognitive decline, and functional independence. Occasional cannabis users showed better global cognitive performance overall compared to non-cannabis users. Rates of cognitive decline and functional problems did not vary by average cannabis use. Recent cannabis use was linked to worse cognition at study visits when participants had THC+ urine toxicology-this short-term decrement in cognition was driven by worse memory and did not extend to reports of functional declines. Occasional (≤ weekly) cannabis use was associated with better global cognition over time in older adults with HIV, a group vulnerable to chronic inflammation and cognitive impairment. Recent THC exposure may have a temporary adverse impact on memory. To inform safe and efficacious medical cannabis use, the effects of specific cannabinoid doses on cognition and biological mechanisms must be investigated in older adults.

Altered large-scale brain network interactions associated with HIV infection and error processing

Altered activity within and between large-scale brain networks has been implicated across various neuropsychiatric conditions. However, patterns of network dysregulation associated with human immunodeficiency virus (HIV), and further impacted by cannabis (CB) use, remain to be delineated. We examined the impact of HIV and CB on resting-state functional connectivity (rsFC) between brain networks and associations with error awareness and error-related network responsivity. Participants (N = 106), stratified into four groups (HIV+/CB+, HIV+/CB-, HIV-/CB+, HIV-/CB-), underwent fMRI scanning while completing a resting-state scan and a modified Go/NoGo paradigm assessing brain responsivity to errors and explicit error awareness. We examined separate and interactive effects of HIV and CB on resource allocation indexes (RAIs), a measure quantifying rsFC strength between the default mode network (DMN), central executive network (CEN), and salience network (SN). We observed reduced RAIs among HIV+ (vs. HIV-) participants, which was driven by increased SN-DMN rsFC. No group differences were detected for SN-CEN rsFC. Increased SN-DMN rsFC correlated with diminished error awareness, but not with error-related network responsivity. These outcomes highlight altered network interactions among participants with HIV and suggest such rsFC dysregulation may persist during task performance, reflecting an inability to disengage irrelevant mental operations, ultimately hindering error processing.

Interactive Effects of HIV Infection and Cannabis Use on Insula Subregion Functional Connectivity

Chronic inflammation in the central nervous system is one mechanism through which human immunodeficiency virus (HIV) may lead to progressive cognitive decline. Given cannabis's (CB's) anti-inflammatory properties, use prevalence among people living with HIV (PLWH), and evidence implicating the insula in both, we examined independent and interactive effects of HIV and CB on insular circuitry, cognition, and immune function. We assessed resting-state functional connectivity (rsFC) of three insula subregions among 106 participants across four groups (co-occurring: HIV+/CB+; HIV-only: HIV+/CB-; CB-only: HIV-/CB+; controls: HIV-/CB-). Participants completed a neurocognitive battery assessing functioning across multiple domains and self-reported somatic complaints. Blood samples quantified immune function (T-cell counts) and inflammation (tumor necrosis factor alpha [TNF-α]). We observed interactive HIV × CB effects on rsFC strength between two anterior insula (aI) subregions and sensorimotor cortices such that, CB appeared to normalize altered rsFC among non-using PLWH. Specifically, compared to controls, HIV-only and CB-only groups displayed decreased dorsal anterior insula (DI) - postcentral gyrus rsFC and increased ventral anterior insula (VI) - supplementary motor area rsFC, whereas the co-occurring group displayed DI and VI rsFC more akin to that of controls. Altered DI - postcentral rsFC correlated with decreased processing speed and somatic complaints, but did not significantly correlate with inflammation (TNF-α). These outcomes implicate insula - sensorimotor neurocircuitries in HIV and CB and are consistent with prior work suggesting that CB use may normalize insula functioning among PLWH.

Cannabinoids Reduce Extracellular Vesicle Release from HIV-1 Infected Myeloid Cells and Inhibit Viral Transcription

Of the 37.9 million individuals infected with human immunodeficiency virus type 1 (HIV-1), approximately 50% exhibit HIV-associated neurocognitive disorders (HAND). We and others previously showed that HIV-1 viral RNAs, such as trans-activating response (TAR) RNA, are incorporated into extracellular vesicles (EVs) and elicit an inflammatory response in recipient naïve cells. Cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC), the primary cannabinoids present in cannabis, are effective in reducing inflammation. Studies show that cannabis use in people living with HIV-1 is associated with lower viral load, lower circulating CD16+ monocytes and high CD4+ T-cell counts, suggesting a potentially therapeutic application. Here, HIV-1 infected U1 monocytes and primary macrophages were used to assess the effects of CBD. Post-CBD treatment, EV concentrations were analyzed using nanoparticle tracking analysis. Changes in intracellular and EV-associated viral RNA were quantified using RT-qPCR, and changes in viral proteins, EV markers, and autophagy proteins were assessed by Western blot. Our data suggest that CBD significantly reduces the number of EVs released from infected cells and that this may be mediated by reducing viral transcription and autophagy activation. Therefore, CBD may exert a protective effect by alleviating the pathogenic effects of EVs in HIV-1 and CNS-related infections.

Integration of Cannabis Extract Tetrahydrocannabinol:Cannabidiol in an Interdisciplinary Therapy Setting: A Case of Chronic Multilocular Pain Disorder

Multilocular pain syndromes with advanced chronification lead to a significant reduction in the quality of life of patients. The administration of cannabis is currently being discussed in the context of therapy-resistant pain and increasing opiate abuse. In this case study, possible side effects from the administration of a cannabis extract tetrahydrocannabinol:cannabidiol are examined. Furthermore, the effect on pain intensity and sleep quality is recorded. Due to numerous comorbidities in the patient, interactions with other medications are documented.

HIV infection is linked with reduced error-related default mode network suppression and poorer medication management abilities

OBJECTIVE

Brain activity linked with error processing has rarely been examined among persons living with HIV (PLWH) despite importance for monitoring and modifying behaviors that could lead to adverse health outcomes (e.g., medication non-adherence, drug use, risky sexual practices). Given that cannabis (CB) use is prevalent among PLWH and impacts error processing, we assessed the influence of HIV serostatus and chronic CB use on error-related brain activity while also considering associated implications for everyday functioning and clinically-relevant disease management behaviors.

METHODS

A sample of 109 participants, stratified into four groups by HIV and CB (HIV+/CB+, n = 32; HIV+/CB-, n = 27; HIV-/CB+, n = 28; HIV-/CB-, n = 22), underwent fMRI scanning while completing a modified Go/NoGo paradigm called the Error Awareness Task (EAT). Participants also completed a battery of well-validated instruments including a subjective report of everyday cognitive failures and an objective measure of medication management abilities.

RESULTS

Across all participants, we observed expected error-related anterior insula (aI) activation which correlated with better task performance (i.e., less errors) and, among HIV- participants, fewer self-reported cognitive failures. Regarding awareness, greater insula activation as well as greater posterior cingulate cortex (PCC) deactivation were notably linked with aware (vs. unaware) errors. Regarding group effects, unlike HIV- participants, PLWH displayed a lack of error-related deactivation in two default mode network (DMN) regions (i.e., PCC, medial prefrontal cortex [mPFC]). No CB main or interaction effects were detected. Across all participants, reduced error-related PCC deactivation correlated with reduced medication management abilities and PCC deactivation mediated the effect of HIV on such abilities. More lifetime CB use was linked with reduced error-related mPFC deactivation among HIV- participants and poorer medication management across CB users.

CONCLUSIONS

These results demonstrate that insufficient error-related DMN suppression linked with HIV infection, as well as chronic CB use among HIV- participants, has real-world consequences for medication management behaviors. We speculate that insufficient DMN suppression may reflect an inability to disengage task irrelevant mental operations, ultimately hindering error monitoring and behavior modification.

The neurocognitive effects of a past cannabis use disorder in a diverse sample of people living with HIV

People living with HIV (PLWH) report higher rates of cannabis use than the general population, a trend likely to continue in light of recent policy changes and the reported therapeutic benefits of cannabis for PLWH. Therefore, it is important to better understand cannabis-associated effects on neurocognition, especially as PLWH are at heightened risk for neurocognitive impairment. This study aimed to elucidate the effects of a past cannabis use disorder on current neurocognition in a diverse sample of PLWH. This cross-sectional study included 138 PLWH (age M(SD) = 47.28(8.06); education M(SD) = 12.64(2.73); 73% Male; 71% Latinx) who underwent neuropsychological, DSM-diagnostic, and urine toxicology evaluations. One-way ANCOVAs were conducted to examine effects of a past cannabis use disorder (CUD+) on tests of attention/working memory, processing speed, executive functioning, verbal fluency, learning, memory, and motor ability. Compared to the past CUD- group, the past CUD+ group performed significantly better on tests of processing speed, visual learning and memory, and motor ability (p's < .05). Findings suggest PLWH with past cannabis use have similar or better neurocognition across domains compared to PLWH without past use.

HIV Transgenic Rats Demonstrate Impaired Sensorimotor Gating But Are Insensitive to Cannabinoid (Δ9-Tetrahydrocannabinol)-Induced Deficits

BACKGROUND

HIV-associated neurocognitive disorder (HAND) is commonly observed in persons living with HIV (PWH) and is characterized by cognitive deficits implicating disruptions of fronto-striatal neurocircuitry. Such circuitry is also susceptible to alteration by cannabis and other drugs of abuse. PWH use cannabis at much higher rates than the general population, thus prioritizing the characterization of any interactions between HIV and cannabinoids on cognitively relevant systems. Prepulse inhibition (PPI) of the startle response, the process by which the motor response to a startling stimulus is attenuated by perception of a preceding non-startling stimulus, is an operational assay of fronto-striatal circuit integrity that is translatable across species. PPI is reduced in PWH. The HIV transgenic (HIVtg) rat model of HIV infection mimics numerous aspects of HAND, although to date the PPI deficit observed in PWH has yet to be fully recreated in animals.

METHODS

PPI was measured in male and female HIVtg rats and wild-type controls following acute, nonconcurrent treatment with the primary constituents of cannabis: Δ 9-tetrahydrocannabinol (THC; 1 and 3 mg/kg, s.c.) and cannabidiol (1, 10, and 30 mg/kg, i.p.).

RESULTS

HIVtg rats exhibited a significant PPI deficit relative to wild-type controls. THC reduced PPI in controls but not HIVtg rats. Cannabidiol exerted only minor, genotype-independent effects on PPI.

CONCLUSIONS

HIVtg rats exhibit a relative insensitivity to the deleterious effects of THC on the fronto-striatal function reflected by PPI, which may partially explain the higher rates of cannabis use among PWH.

General risks of harm with cannabinoids, cannabis, and cannabis-based medicine possibly relevant to patients receiving these for pain management: an overview of systematic reviews

ABSTRACT

The growing demand for improved pain treatments together with expanding legalization of, and access to, cannabinoids, cannabis, and cannabis-based medicines has intensified the focus on risk-benefit considerations in pain management. Given limited harms data from analgesic clinical trials, we conducted an overview of systematic reviews focused on all harms possibly relevant to patients receiving cannabinoids for pain management. This PROSPERO-registered, PRISMA-compliant systematic overview identified 79 reviews, encompassing over 2200 individual reports about psychiatric and psychosocial harms, cognitive/behavioral effects, motor vehicle accidents, cardiovascular, respiratory, cancer-related, maternal/fetal, and general harms. Reviews, and their included studies, were of variable quality. Available evidence suggests variable associations between cannabis exposure (ranging from monthly to daily use based largely on self-report) and psychosis, motor vehicle accidents, respiratory problems, and other harms. Most evidence comes from settings other than that of pain management (eg, nonmedicinal and experimental) but does signal a need for caution and more robust harms evaluation in future studies. Given partial overlap between patients receiving cannabinoids for pain management and individuals using cannabinoids for other reasons, lessons from the crisis of oversupply and overuse of opioids in some parts of the world emphasize the need to broadly consider harms evidence from real-world settings. The advancement of research on cannabinoid harms will serve to guide optimal approaches to the use of cannabinoids for pain management. In the meantime, this evidence should be carefully examined when making risk-benefit considerations about the use of cannabinoids, cannabis, and cannabis-based medicine for chronic pain.

Daily Cannabis Use is Associated With Lower CNS Inflammation in People With HIV

OBJECTIVE

Recent cannabis exposure has been associated with lower rates of neurocognitive impairment in people with HIV (PWH). Cannabis's anti-inflammatory properties may underlie this relationship by reducing chronic neuroinflammation in PWH. This study examined relations between cannabis use and inflammatory biomarkers in cerebrospinal fluid (CSF) and plasma, and cognitive correlates of these biomarkers within a community-based sample of PWH.

METHODS

263 individuals were categorized into four groups: HIV- non-cannabis users (n = 65), HIV+ non-cannabis users (n = 105), HIV+ moderate cannabis users (n = 62), and HIV+ daily cannabis users (n = 31). Differences in pro-inflammatory biomarkers (IL-6, MCP-1/CCL2, IP-10/CXCL10, sCD14, sTNFR-II, TNF-α) by study group were determined by Kruskal-Wallis tests. Multivariable linear regressions examined relationships between biomarkers and seven cognitive domains, adjusting for age, sex/gender, race, education, and current CD4 count.

RESULTS

HIV+ daily cannabis users showed lower MCP-1 and IP-10 levels in CSF compared to HIV+ non-cannabis users (p = .015; p = .039) and were similar to HIV- non-cannabis users. Plasma biomarkers showed no differences by cannabis use. Among PWH, lower CSF MCP-1 and lower CSF IP-10 were associated with better learning performance (all ps < .05).

CONCLUSIONS

Current daily cannabis use was associated with lower levels of pro-inflammatory chemokines implicated in HIV pathogenesis and these chemokines were linked to the cognitive domain of learning which is commonly impaired in PWH. Cannabinoid-related reductions of MCP-1 and IP-10, if confirmed, suggest a role for medicinal cannabis in the mitigation of persistent inflammation and cognitive impacts of HIV.

Confound, Cause, or Cure: The Effect of Cannabinoids on HIV-Associated Neurological Sequelae

The persistence of human immunodeficiency virus-1 (HIV)-associated neurocognitive disorders (HAND) in the era of effective antiretroviral therapy suggests that modern HIV neuropathogenesis is driven, at least in part, by mechanisms distinct from the viral life cycle. Identifying more subtle mechanisms is complicated by frequent comorbidities in HIV⁺ populations. One of the common confounds is substance abuse, with cannabis being the most frequently used psychoactive substance among people living with HIV. The psychoactive effects of cannabis use can themselves mimic, and perhaps magnify, the cognitive deficits observed in HAND; however, the neuromodulatory and anti-inflammatory properties of cannabinoids may counter HIV-induced excitotoxicity and neuroinflammation. Here, we review our understanding of the cross talk between HIV and cannabinoids in the central nervous system by exploring both clinical observations and evidence from preclinical in vivo and in vitro models. Additionally, we comment on recent advances in human, multi-cell in vitro systems that allow for more translatable, mechanistic studies of the relationship between cannabinoid pharmacology and this uniquely human virus.

A Mapping Literature Review of Medical Cannabis Clinical Outcomes and Quality of Evidence in Approved Conditions in the USA from 2016 to 2019

In 2017, a National Academies of Sciences, Engineering, and Medicine (NASEM) report comprehensively evaluated the body of evidence regarding cannabis health effects through the year 2016. The objectives of this study are to identify and map the most recently (2016-2019) published literature across approved conditions for medical cannabis and to evaluate the quality of identified recent systematic reviews, published following the NASEM report. Following the literature search from 5 databases and consultation with experts, 11 conditions were identified for evidence compilation and evaluation: amyotrophic lateral sclerosis, autism, cancer, chronic noncancer pain, Crohn's disease, epilepsy, glaucoma, human immunodeficiency virus/AIDS, multiple sclerosis (MS), Parkinson's disease, and posttraumatic stress disorder. A total of 198 studies were included after screening for condition-specific relevance and after imposing the following exclusion criteria: preclinical focus, non-English language, abstracts only, editorials/commentary, case studies/series, and non-U.S. study setting. Data extracted from studies included: study design type, outcome definition, intervention definition, sample size, study setting, and reported effect size. Few completed randomized controlled trials (RCTs) were identified. Studies classified as systematic reviews were graded using the Assessing the Methodological Quality of Systematic Reviews-2 tool to evaluate the quality of evidence. Few high-quality systematic reviews were available for most conditions, with the exceptions of MS (9 of 9 graded moderate/high quality; evidence for 2/9 indicating cannabis improved outcomes; evidence for 7/9 indicating cannabis inconclusive), epilepsy (3 of 4 graded moderate/high quality; 3 indicating cannabis improved outcomes; 1 indicating cannabis inconclusive), and chronic noncancer pain (12 of 13 graded moderate/high quality; evidence for 7/13 indicating cannabis improved outcomes; evidence from 6/7 indicating cannabis inconclusive). Among RCTs, we identified few studies of substantial rigor and quality to contribute to the evidence base. However, there are some conditions for which significant evidence suggests that select dosage forms and routes of administration likely have favorable risk-benefit ratios (i.e., epilepsy and chronic noncancer pain). The body of evidence for medical cannabis requires more rigorous evaluation before consideration as a treatment option for many conditions, and evidence necessary to inform policy and treatment guidelines is currently insufficient for many conditions.

Cannabis and the Gut-Brain Axis Communication in HIV Infection

People living with HIV infection (PWH) disclose that cannabis is an effective strategy for alleviating symptoms associated with HIV disease. However, some medical providers feel ill-informed to engage in evidence-based conversations. HIV leads to alterations in the gut microbiome, gut-brain axis signaling, and chronic inflammation. The endocannabinoid system regulates homeostasis of multiple organ systems. When deficient, dysregulation of the gut-brain axis can result in chronic inflammation and neuroinflammation. Cannabis along with the naturally occurring endocannabinoids has antioxidant and anti-inflammatory properties that can support healing and restoration as an adjunctive therapy. The purpose of this literature review is to report the physiologic mechanisms that occur in the pathology of HIV and discuss potential benefits of cannabinoids in supporting health and reducing the negative effects of comorbidities in PWH.

Understanding disparities in viral suppression among Black MSM living with HIV in Atlanta Georgia

INTRODUCTION

Due to factors associated with structural racism, Black men who have sex with men (MSM) living with HIV are less likely to be virally suppressed compared to white MSM. Most of these data come from clinical cohorts and modifiable reasons for these racial disparities need to be defined in order to intervene on these inequities. Therefore, we examined factors associated with racial disparities in baseline viral suppression in a community-based cohort of Black and white MSM living with HIV in Atlanta, GA.

METHODS

We conducted an observational cohort of Black and white MSM living with HIV infection in Atlanta. Enrolment occurred from June 2016 to June 2017 and men were followed for 24 months; laboratory and behavioural survey data were collected at 12 and 24 months after enrolment. Explanatory factors for racial disparities in viral suppression included sociodemographics and psychosocial variables. Poisson regression models with robust error variance were used to estimate prevalence ratios (PR) for Black/white differences in viral suppression. Factors that diminished the PR for race by ≥5% were considered to meaningfully attenuate the racial disparity and were included in a multivariable model.

RESULTS

Overall, 26% (104/398) of participants were not virally suppressed at baseline. Lack of viral suppression was significantly more prevalent among Black MSM (33%; 69/206) than white MSM (19%; 36/192) (crude Prevalence Ratio (PR) = 1.6; 95% CI: 1.1 to 2.5). The age-adjusted Black/white PR was diminished by controlling for: ART coverage (12% decrease), housing stability (7%), higher income (6%) and marijuana use (6%). In a multivariable model, these factors cumulatively mitigated the PR for race by 21% (adjusted PR = 1.1 [95% CI: 0.8 to 1.6]).

CONCLUSIONS

Relative to white MSM, Black MSM living with HIV in Atlanta were less likely to be virally suppressed. This disparity was explained by several factors, many of which should be targeted for structural, policy and individual-level interventions to reduce racial disparities.

Mini-review: The therapeutic role of cannabinoids in neuroHIV

In the era of combined antiretroviral therapy (cART), human immunodeficiency virus type 1 (HIV-1) is considered a chronic disease with an inflammatory component that specifically targets the brain and causes a high prevalence of HIV-1-associated neurocognitive disorders (HAND). The endocannabinoid (eCB) system has attracted interest as a target for treatment of neurodegenerative disorders, due to the potential anti-inflammatory and neuroprotective properties of cannabinoids, including its potential therapeutic use in HIV-1 neuropathogenesis. In this review, we summarize what is currently known about the structural and functional changes of the eCB system under conditions of HAND. This will be followed by summarizing the current clinical and preclinical findings on the effects of cannabis use and cannabinoids in the context of HIV-1 infection, with specifically focusing on viral load, cognition, inflammation, and neuroprotection. Lastly, we present some potential future directions to better understand the involvement of the eCB system and the role that cannabis use and cannabinoids play in neuroHIV.

Synergistic effects of HIV and marijuana use on functional brain network organization

HIV is associated with disruptions in cognition and brain function. Marijuana use is highly prevalent in HIV but its effects on resting brain function in HIV are unknown. Brain function can be characterized by brain activity that is correlated between regions over time, called functional connectivity. Neuropsychiatric disorders are increasingly being characterized by disruptions in such connectivity. We examined the synergistic effects of HIV and marijuana use on functional whole-brain network organization during resting state. Our sample included 78 adults who differed on HIV and marijuana status (19 with co-occurring HIV and marijuana use, 20 HIV-only, 17 marijuana-only, and 22 controls). We examined differences in local and long-range brain network organization using eight graph theoretical metrics: transitivity, local efficiency, within-module degree, modularity, global efficiency, strength, betweenness, and participation coefficient. Local and long-range connectivity were similar between the co-occurring HIV and marijuana use and control groups. In contrast, the HIV-only and marijuana-only groups were both associated with disruptions in brain network organization. These results suggest that marijuana use in HIV may normalize disruptions in brain network organization observed in persons with HIV. However, future work is needed to determine whether this normalization is suggestive of a beneficial or detrimental effect of marijuana on cognitive functioning in HIV.

Perceptions of quality and safety in cannabis acquisition amongst young gay and bisexual men living with HIV/AIDS who use cannabis: Impact of legalisation and dispensaries

BACKGROUND

Upwards of 35% of young gay and bisexual men living with HIV report daily use of cannabis in the U.S. The effects of legalisation of recreational and medical cannabis on the acquisition of cannabis products amongst a group with such high prevalence of use is largely unknown.

METHODS

We investigated potential effects of recent legalisation and changes in distribution venues/networks in U.S. jurisdictions (Denver and Chicago) with different legal statuses regarding medical and recreational cannabis. We conducted semi-structured interviews with 30 young gay and bisexual men living with HIV recruited from adolescent HIV clinics and service sites in the two cities.

RESULTS

Findings indicate four domains in which the acquisition of cannabis from medical or recreational dispensaries was differentiated by participants from acquisition from illicit drug distribution networks: quality of information, perceived quality of products, safety of acquisition, and safety of products. Some participants expressed reservations in becoming involved with requirements for accessing legal distribution of medical and recreational cannabis.

CONCLUSIONS

Our findings indicate that young men living with HIV in Denver perceive benefits from legalisation of cannabis in terms of quality of information and products and safety of acquisition for a range of medical, therapeutic, and recreational uses. Participants in Chicago report mixed levels of knowledge of potential benefits through the medical cannabis dispensaries in their area, and continue to be exposed to safety risks associated with street-based acquisition. Concerns regarding institutional involvement in medical cannabis registries and dispensaries may inhibit the uptake of legal means of acquisition in sub-populations of young men living with HIV.

Reciprocal Influences of HIV and Cannabinoids on the Brain and Cognitive Function

Globally, cannabis is the most commonly used illicit drug, with disproportionately high use among persons with HIV. Despite advances in HIV care, nearly half of persons living with HIV continue to experience neurocognitive deficits or impairments that may have negative impacts on their daily function. Chronic cannabis use may play a role in the development or exacerbation of these impairments. Here we present a review summarizing existing research detailing the effect of cannabis use associated with the neuropathogenesis of HIV. We examine evidence for possible additive or synergistic effects of HIV infection and cannabis use on neuroHIV in both the preclinical and adult human literatures, including in vitro studies, animal models, clinical neuroimaging research, and studies examining the cognitive effects of cannabis. We discuss the limitations of existing research, including methodological challenges involved with clinical research with human subjects. We identify gaps in the field and propose critical research questions to advance our understanding of how cannabis use affects neuroHIV. Graphical Abstract.

Methamphetamine and Cannabis: A Tale of Two Drugs and their Effects on HIV, Brain, and Behavior

HIV infection and drug use intersect epidemiologically, and their combination can result in complex effects on brain and behavior. The extent to which drugs affect the health of persons with HIV (PWH) depends on many factors including drug characteristics, use patterns, stage of HIV disease and its treatment, comorbid factors, and age. To consider the range of drug effects, we have selected two that are in common use by PWH: methamphetamine and cannabis. We compare the effects of methamphetamine with those of cannabis, to illustrate how substances may potentiate, worsen, or even buffer the effects of HIV on the CNS. Data from human, animal, and ex vivo studies provide insights into how these drugs have differing effects on the persistent inflammatory state that characterizes HIV infection, including effects on viral replication, immune activation, mitochondrial function, gut permeability, blood brain barrier integrity, glia and neuronal signaling. Moving forward, we consider how these mechanistic insights may inform interventions to improve brain outcomes in PWH. This review summarizes literature from clinical and preclinical studies demonstrating the adverse effects of METH, as well as the potentially beneficial effects of cannabis, on the interacting systemic (e.g., gut barrier leakage/microbial translocation, immune activation, inflammation) and CNS-specific (e.g., glial activation/neuroinflammation, neural injury, mitochondrial toxicity/oxidative stress) mechanisms underlying HIV-associated neurocognitive disorders.

Microstructural brain abnormalities in HIV+ individuals with or without chronic marijuana use

OBJECTIVE

Cognitive deficits and microstructural brain abnormalities are well documented in HIV-positive individuals (HIV+). This study evaluated whether chronic marijuana (MJ) use contributes to additional cognitive deficits or brain microstructural abnormalities that may reflect neuroinflammation or neuronal injury in HIV+.

METHOD

Using a 2 × 2 design, 44 HIV+ participants [23 minimal/no MJ users (HIV+), 21 chronic active MJ users (HIV + MJ)] were compared to 46 seronegative participants [24 minimal/no MJ users (SN) and 22 chronic MJ users (SN + MJ)] on neuropsychological performance (7 cognitive domains) and diffusion tensor imaging metrics, using an automated atlas to assess fractional anisotropy (FA), axial (AD), radial (RD), and mean (MD) diffusivities, in 18 cortical and 4 subcortical brain regions.

RESULTS

Compared to SN and regardless of MJ use, the HIV+ group had lower FA and higher diffusivities in multiple white matter and subcortical structures (p < 0.001-0.050), as well as poorer cognition in Fluency (p = 0.039), Attention/Working Memory (p = 0.009), Learning (p = 0.014), and Memory (p = 0.028). Regardless of HIV serostatus, MJ users had lower AD in uncinate fasciculus (p = 0.024) but similar cognition as nonusers. HIV serostatus and MJ use showed an interactive effect on mean diffusivity in the right globus pallidus but not on cognitive function. Furthermore, lower FA in left anterior internal capsule predicted poorer Fluency across all participants and worse Attention/Working Memory in all except SN subjects, while higher diffusivities in several white matter tracts also predicted lower cognitive domain Z-scores. Lastly, MJ users with or without HIV infection showed greater than normal age-dependent FA declines in superior longitudinal fasciculus, external capsule, and globus pallidus.

CONCLUSIONS

Our findings suggest that, except in the globus pallidus, chronic MJ use had no additional negative influence on brain microstructure or neurocognitive deficits in HIV+ individuals. However, lower AD in the uncinate fasciculus of MJ users suggests axonal loss in this white matter tract that connects to cannabinoid receptor rich brain regions that are involved in verbal memory and emotion. Furthermore, the greater than normal age-dependent FA declines in the white matter tracts and globus pallidus in MJ users suggest that older chronic MJ users may eventually have lesser neuronal integrity in these brain regions.

Impact of Cannabis Use on Brain Structure and Function in Suppressed HIV Infection

BACKGROUND

Brain atrophy and cognitive deficits persist among individuals with suppressed HIV disease. The impact of cannabis use is unknown.

METHODS

HIV+ and HIV- participants underwent cross-sectional magnetic resonance imaging and neuropsychological testing. Lifetime frequency, duration (years), and recency of cannabis use were self-reported. Relationships of cannabis use to resting-state functional connectivity (RSFC) and to 9 regional brain volumes were assessed with corrections for multiple comparisons. Peripheral blood cytokines and monocyte subsets were measured in the HIV+ group and examined in relation to cannabis exposure.

RESULTS

We evaluated 52 HIV+ [50.8 ± 7.1 years old; 100% on antiretroviral therapy ≥ 3 months; 83% with plasma viral load < 50 copies/mL] and 55 HIV- [54.0 ± 7.5 years old] individuals. Among HIV+ participants, recent cannabis use (within 12 months) was associated with diminished RSFC, including of occipital cortex, controlling for age. Duration of use correlated negatively with volumes of all regions (most strikingly the nucleus accumbens) independently of recent use and intracranial volume. Recent use was associated with larger caudate and white matter volumes and lower soluble vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1 concentrations. Duration of use correlated positively with psychomotor speed. Use > 10 times/lifetime was linked to more somatic symptoms, better executive function, and lower CD14⁺CD16⁺⁺ monocyte count.

CONCLUSION

HIV+ individuals demonstrated opposing associations with cannabis. Recent use may weaken RSFC and prolonged consumption may exacerbate atrophy of the accumbens and other brain regions. More frequent or recent cannabis use may reduce the inflammation and CD14⁺CD16⁺⁺ monocytes that facilitate HIV neuroinvasion. HIV-specific cannabis studies are necessary.

Cannabis Exposure is Associated With a Lower Likelihood of Neurocognitive Impairment in People Living With HIV

BACKGROUND

Aging and HIV have adverse effects on the central nervous system, including increased inflammation and neural injury and confer risk of neurocognitive impairment (NCI). Previous research suggests the nonacute neurocognitive effects of cannabis in the general population are adverse or null. However, in the context of aging and HIV, cannabis use may exert beneficial effects due to its anti-inflammatory properties. In the current study, we examined the independent and interactive effects of HIV and cannabis on NCI and the potential moderation of these effects by age.

METHODS

Participants included 679 people living with HIV (PLHIV) and 273 people living without HIV (HIV-) (18-79 years old) who completed neurocognitive, neuromedical, and substance use assessments. NCI was defined as a demographically corrected global deficit score ≥ 0.5. Logistic regression models examined the effects of age, HIV, cannabis (history of cannabis substance use disorder and cannabis use in past year), and their 2-way and 3-way interactions on NCI.

RESULTS

In logistic regression models, only a significant interaction of HIV X cannabis was detected (P = 0.02). Among PLHIV, cannabis was associated with a lower proportion of NCI (odds ratio = 0.53, 95% confidence interval = 0.33-0.85) but not among HIV- individuals (P = 0.40). These effects did not vary by age.

CONCLUSIONS

Findings suggest cannabis exposure is linked to a lower odds of NCI in the context of HIV. A possible mechanism of this result is the anti-inflammatory effect of cannabis, which may be particularly important for PLHIV. Further investigations are needed to refine the effects of dose, timing, and cannabis compound on this relationship, which could inform guidelines for cannabis use among populations vulnerable to cognitive decline.

Clinical Data for the Use of Cannabis-Based Treatments: A Comprehensive Review of the Literature

Objective:

To compile and synthesize the available literature describing medical cannabis use across various disease states.

Data Sources:

PubMed, EBSCO, and Google Scholar searches were conducted using MeSH and/or keywords.

Study Selection and Data Extraction:

Studies were included if they described the use of cannabis-based products and medications in the treatment of a predefined list of disease states in humans and were published in English. The extraction period had no historical limit and spanned through April 2019.

Data Synthesis:

Evidence was compiled and summarized for the following medical conditions: Alzheimer disease, amyotrophic lateral sclerosis, autism, cancer and cancer-associated adverse effects, seizure disorders, human immunodeficiency virus, inflammatory bowel disease, multiple sclerosis (MS), nausea, pain, posttraumatic stress disorder, and hospice care.

Relevance to Patient Care and Clinical Practice:

Based on identified data, the most robust evidence suggests that medical cannabis may be effective in the treatment of chemotherapy-induced nausea and vomiting, seizure disorders, MS-related spasticity, and pain (excluding diabetic neuropathy). Overall, the evidence is inconsistent and generally limited by poor quality. The large variation in cannabis-based products evaluated in studies limits the ability to make direct comparisons. Regardless of the product, a gradual dose titration was utilized in most studies. Cannabis-based therapies were typically well tolerated, with the most common adverse effects being dizziness, somnolence, dry mouth, nausea, and euphoria.

Conclusions:

As more states authorize medical cannabis use, there is an increasing need for high-quality clinical evidence describing its efficacy and safety. This review is intended to serve as a reference for clinicians, so that the risks and realistic benefits of medical cannabis are better understood.

Striatal and white matter volumes in chronic ketamine users with or without recent regular stimulant use

BACKGROUND

Previous studies found enlarged striatum and white matter in those with stimulants use disorders. Whether primarily ketamine users (Primarily-K) and ketamine users who co-used stimulants and other substances (K+PolyS) have abnormal brain volumes is unknown. This study aims to evaluate possible brain structural abnormalities, cognitive function and depressive symptoms, between Primarily-K and K+PolyS users.

METHODS

Striatal and white matter volumes were automatically segmented in 39 Primarily-K users, 41 K+PolyS users and 46 non-drug users (ND). Cognitive performance in 7 neurocognitive domains and depressive symptoms were also evaluated.

RESULTS

Ketamine users had larger caudates than ND-controls (Right: 1-way-ANCOVA-p=0.035; K+PolyS vs. ND, p=0.030; Linear trend for K+PolyS>Primarily-K>ND, p=0.011; Left: 1-way-ANCOVA-p=0.047, Primarily-K vs. ND p=0.051) and larger total white matter (1-way ANCOVA-p=0.009, Poly+K vs. Primarily-K, p=0.05; Poly+K vs. ND p=0.011; Linear trend for K+PolyS>Primarily-K >ND, p=0.004). Across all ketamine users, they performed poorer on Arithmetic, learning and memory tasks, and were more depressed than Non-users (p<0.001 to p=0.001). Greater lifetime ketamine usage correlated with more depressive symptoms (r=0.27, p=0.008). Larger white matter correlated with better learning across all participants (r=0.21, p=0.019), while larger right caudate correlated with lower depression scores in ketamine users (r=-0.28, p=0.013).

CONCLUSION

Ketamine users had larger caudates and total white matter than ND-controls. The even larger white matter in K+PolyS users suggests additive effects from co-use of ketamine and stimulants. However, across the ketamine users, since greater volumes were associated with better learning and less depressive symptom, the enlarged caudates and white matter might represent a compensatory response.

Synergistic effects of marijuana abuse and HIV infection on neural activation during a cognitive interference task

Marijuana use, which is disproportionately prevalent among human immunodeficiency virus (HIV)-infected persons, can alter activity in fronto-parietal regions during cognitively demanding tasks. While HIV is also associated with altered neural activation, it is not known how marijuana may further affect brain function in this population. Our study examined the independent and additive effects of HIV infection and regular marijuana use on neural activation during a cognitive interference task. The sample included 93 adults who differed on marijuana (MJ) and HIV statuses (20 MJ+/HIV+, 19 MJ+/HIV-, 29 MJ-/HIV+, 25 MJ-/HIV-). Participants completed a counting Stroop task during a functional magnetic resonance imaging scan. Main and interactive effects on neural activation during interference versus neutral blocks were examined using a mixed-effects analysis. The sample showed the expected Stroop effect for both speed and accuracy. There were main effects of MJ in the right and left inferior parietal lobules, with the left cluster extending into the posterior middle temporal gyrus and a main effect of HIV in the dorsal anterior cingulate cortex. There was an interaction in the left fronto-insular cortex, such that the MJ+/HIV+ group had the largest increase in activation compared with other groups. Among MJ+, signal change in this cluster correlated positively with cumulative years of regular marijuana use. These results suggest that comorbid HIV and marijuana use is associated with complex neural alterations in multiple brain regions during cognitive interference. Follow-up research is needed to determine how marijuana-related characteristics may moderate HIV neurologic disease and impact real-world functioning.

Druggable targets of the endocannabinoid system: Implications for the treatment of HIV-associated neurocognitive disorder

HIV-associated neurocognitive disorder (HAND) affects nearly half of all HIV-infected individuals. Synaptodendritic damage correlates with neurocognitive decline in HAND, and many studies have demonstrated that HIV-induced neuronal injury results from excitotoxic and inflammatory mechanisms. The endocannabinoid (eCB) system provides on-demand protection against excitotoxicity and neuroinflammation. Here, we discuss evidence of the neuroprotective and anti-inflammatory properties of the eCB system from in vitro and in vivo studies. We examine the pharmacology of the eCB system and evaluate the therapeutic potential of drugs that modulate eCB signaling to treat HAND. Finally, we provide perspective on the need for additional studies to clarify the role of the eCB system in HIV neurotoxicity and speculate that strategies that enhance eCB signaling might slow cognitive decline in HAND.

Cognitive Trajectory Phenotypes in Human Immunodeficiency Virus-Infected Patients

OBJECTIVE

The presentation of cognitive impairments in HIV-infected individuals has transformed since the introduction of antiretroviral therapies. Although the overall prevalence of cognitive impairments has not changed considerably, frank dementia is now infrequent, and milder forms of cognitive impairments predominate. Mechanistic insights to the underlying causes of these residual cognitive impairments have been elusive, in part due to the heterogenous etiology of cognitive dysfunction in this population. Here, we sought to categorize longitudinal change in HIV-infected patients based on the performance in specific cognitive domains.

DESIGN

This study consisted of 193 participants from the CHARTER cohort with detailed demographic, clinical, and neuropsychological testing data obtained from 2 study visits interspersed by ∼6 months. Cognitive testing assessed executive function, learning and delayed recall, working memory, verbal fluency, speed of information processing, and motor skills. Change scores were calculated for each domain between the 2 study visits. Dimension reduction and clustering was accomplished by principal component analysis of change scores and k-means clustering to identify cognitive domains that group together and groups of subjects with similar patterns of change.

RESULTS

We identified 4 distinct cognitive change phenotypes that included declines in: (1) verbal fluency, (2) executive function (3) learning and recall, and (4) motor function, with approximately equal numbers of participants in each phenotype.

CONCLUSIONS

Each of the 4 cognitive change phenotypes identify deficits that imply perturbations in specific neural networks. Future studies will need to validate if cognitive change phenotypes are associated with alterations in associated neural pathways.

Total and differential white blood cell count in cannabis users: results from the cross-sectional National Health and Nutrition Examination Survey, 2005-2016

Background

Elevated white blood cell (WBC) count in tobacco cigarette smokers compared to non-smokers has been well documented, but little is known on circulating WBC counts and cannabis use.

Methods

The National Health and Nutrition Examination Survey (2005–2016) is designed to be nationally representative of United States non-institutionalized population. The current study includes adult participants 20–59 years of age (n = 16,430) who underwent a detailed examination in the mobile examination center (MEC). Cannabis use was measured using Audio Computer-Assisted Self-Interview. Cannabis use was classified into never, former, occasional (1–7 days of the past 30 days), and heavy (> 7 days of the past 30 days). WBC count was measured using the Coulter Counter method.

Results

Total WBC count was higher among heavy cannabis users when compared to never users (β = 189; 95% confidence interval: 74, 304, p = 0.001). Among circulating WBC types, modest differences were observed for neutrophil count. Neither former nor occasional cannabis use was associated with total or differential WBC counts.

Conclusions

A modest association between heavy cannabis use and WBC count was detected. Additional research is needed to understand the immune related effects of different modes of cannabis use and to elucidate the role of proinflammatory chemicals generated from smoking cannabis.

Electronic supplementary material

The online version of this article (10.1186/s42238-019-0007-8) contains supplementary material, which is available to authorized users.

Medical, therapeutic, and recreational use of cannabis among young men who have sex with men living with HIV

Cannabis plays a role in symptoms management in HIV, especially the alleviation of pain and nausea and stimulation of appetite, and prevalence of cannabis use in HIV-positive populations exceeds that of the general U.S. population. Previous research has described an "overlap" between medical and recreational cannabis use among persons living with HIV. To understand better the motives associated cannabis use among young men who have sex with men living with HIV (HIV+ YMSM), we conducted semi-structured interviews with 30 HIV+YMSM in Denver and Chicago. Interviews were audio-recorded, transcribed, and coded by a diverse team of analysts. In addition to findings that mapped onto previously identified medical motives and recreational motives, we identified several themes that straddled medical and recreational use in a domain we describe as therapeutic. Themes identified in this therapeutic domain of cannabis use include (a) enhanced introspection among individuals that promotes psychological adjustment to an HIV diagnosis, improved medical management, and future orientation; (b) reflection processes that mitigate interpersonal conflict and improve interpersonal communication; and (c) a social-therapeutic phenomena of cannabis use among young persons with living HIV that is characterized by both enhanced introspection and improved interpersonal communication. Our findings suggest a spectrum of cannabis use among HIV+ YMSM that may be characterized not only by an overlap between medical and recreational use, but also by a distinct therapeutic domain that incorporates stress alleviation and cognitive expansion processes to improve focus on HIV management and self-care.

Confirmed marijuana use and lymphocyte count in black people living with HIV

BACKGROUND

Marijuana is a commonly used recreational substance with purported analgesic and mood enhancing properties. Many people living with HIV identify marijuana as a palliative substance. However, through its main psychoactive component, tetrahydrocannabinol (THC), is known to influence the immune system. The effects of marijuana use in people with HIV are still controversial, with very scant literature in Black adults.

METHODS

The current study determined the differences in the lymphocyte count, specifically the number cluster differentiation 4 and 8 (CD4+ and CD8+), among patients who urine drug tested negative for THC (n = 70) and those who tested positive for THC (n = 25). The sample included 95 Black people living with HIV, 51% female, with a mean age of 46 ± 11 years. Participants provided a urine sample for substance use testing and a trained researcher extracted clinical data from clinical charts on the day of appointment.

RESULTS

After adjusting for demographic and HIV-related covariates, THC-positive patients had significantly higher CD4+ and CD8+ counts than their THC-negative counterparts.

CONCLUSION

These results extend previous HIV-related immunity findings in an underrepresented group, and suggest that THC use does not reduce immune function as measured by CD count. Further research is warranted on the overall effects of THC on immune function in HIV positive patients.

Neurocognitive SuperAging in Older Adults Living With HIV: Demographic, Neuromedical and Everyday Functioning Correlates

OBJECTIVES

Studies of neurocognitively elite older adults, termed SuperAgers, have identified clinical predictors and neurobiological indicators of resilience against age-related neurocognitive decline. Despite rising rates of older persons living with HIV (PLWH), SuperAging (SA) in PLWH remains undefined. We aimed to establish neuropsychological criteria for SA in PLWH and examined clinically relevant correlates of SA.

METHODS

734 PLWH and 123 HIV-uninfected participants between 50 and 64 years of age underwent neuropsychological and neuromedical evaluations. SA was defined as demographically corrected (i.e., sex, race/ethnicity, education) global neurocognitive performance within normal range for 25-year-olds. Remaining participants were labeled cognitively normal (CN) or impaired (CI) based on actual age. Chi-square and analysis of variance tests examined HIV group differences on neurocognitive status and demographics. Within PLWH, neurocognitive status differences were tested on HIV disease characteristics, medical comorbidities, and everyday functioning. Multinomial logistic regression explored independent predictors of neurocognitive status.

RESULTS

Neurocognitive status rates and demographic characteristics differed between PLWH (SA=17%; CN=38%; CI=45%) and HIV-uninfected participants (SA=35%; CN=55%; CI=11%). In PLWH, neurocognitive groups were comparable on demographic and HIV disease characteristics. Younger age, higher verbal IQ, absence of diabetes, fewer depressive symptoms, and lifetime cannabis use disorder increased likelihood of SA. SA reported increased independence in everyday functioning, employment, and health-related quality of life than non-SA.

CONCLUSIONS

Despite combined neurological risk of aging and HIV, youthful neurocognitive performance is possible for older PLWH. SA relates to improved real-world functioning and may be better explained by cognitive reserve and maintenance of cardiometabolic and mental health than HIV disease severity. Future research investigating biomarker and lifestyle (e.g., physical activity) correlates of SA may help identify modifiable neuroprotective factors against HIV-related neurobiological aging. (JINS, 2019, 25, 507-519).

Total and differential white blood cell count in cannabis users: results from the cross-sectional National Health and Nutrition Examination Survey, 2005-2016

BACKGROUND

Elevated white blood cell (WBC) count in tobacco cigarette smokers compared to non-smokers has been well documented, but little is known on circulating WBC counts and cannabis use.

METHODS

The National Health and Nutrition Examination Survey (2005-2016) is designed to be nationally representative of United States non-institutionalized population. The current study includes adult participants 20-59 years of age (n= 16,430) who underwent a detailed examination in the mobile examination center (MEC). Cannabis use was measured using Audio Computer-Assisted Self-Interview. Cannabis use was classified into never, former, occasional (1-7 days of the past 30 days), and heavy (>7 days of the past 30 days). WBC count was measured using the Coulter Counter method.

RESULTS

Total WBC count was higher among heavy cannabis users when compared to never users (β = 189; 95% confidence interval: 74, 304, p = 0.001). Among circulating WBC types, modest differences were observed for neutrophil count. Neither former nor occasional cannabis use was associated with total or differential WBC counts.

CONCLUSIONS

A modest association between heavy cannabis use and WBC count was detected. Additional research is needed to understand the immune related effects of different modes of cannabis use and to elucidate the role of proinflammatory chemicals generated from smoking cannabis.

Inflammatory Mechanisms and Cascades Contributing to Neurocognitive Impairment in HIV/AIDS

Neurocognitive impairment caused by chronic human immunodeficiency virus (HIV) infection is a growing concern. In this chapter we discuss the inflammatory mechanisms underlying the pathology of asymptomatic and mild neurocognitive impairment in the context of antiretroviral therapy. We discuss the role of HIV, viral proteins, and virally infected cells on the development of neuroinflammation and the effect of viral proteins on the cells of the central nervous system.We examine how these collective factors result in an inflammatory context that triggers the development of neurocognitive impairment in HIV. We assess the contribution of antiretrovirals and drugs of abuse, including methamphetamine, cannabis, and opioids, to the neurotoxic and neuroinflammatory milieu that leads to the development of neurocognitive impairment in HIV-infected individuals. We also examined circulating biomarkers, NF-L, sCD163, and sCD14, pertinent to identifying changes in the CNS that could indicate real-time changes in patient physiology. Lastly, we discuss future studies, such as exosomes and the microbiome, which could play a role in the HIV-induced neuroinflammation that eventually manifests as cognitive impairment.

Association of Marijuana Use with Changes in Cognitive Processing Speed and Flexibility for 17 Years in HIV-Seropositive and HIV-Seronegative Men

BACKGROUND

The long-term effects of marijuana on cognition, particularly in the context of HIV is not clear, as extant research shows mixed findings.

OBJECTIVE

To determine associations between current and cumulative exposure to marijuana and changes in cognitive processing speed and flexibility in 788 HIV-seropositive (HIV+) and 1,132 HIV-seronegative (HIV-) men followed for up to 17 years in the Multicenter AIDS Cohort Study.

RESULTS

Among HIV+ men only, current daily marijuana use compared to none-use, was significantly associated with a greater annual percentage decline in cognitive processing speed assessed with the Trail Making Test A (TMTA) (β=-0.41, 95% confidence interval (CI): -0.88, -0.03, p=0.03)] and Symbol Digit Modalities Test (SDMT) (β= -0.14, 95% CI: -0.28, -0.01, p=0.04). Further, monthly marijuana use was associated with greater annual percentage decline in cognitive flexibility assessed with the Trail Making Test B (TMTB) (β= -0.70, 95% CI: -1.34, -0.05; p=0.03] and cognitive processing speed (SDMT) (β= -0.21, 95% CI: -0.40, -0.01, p=0.03). Among the HIV- men only, each 5-marijuana use-years (equivalent to 5-years of daily marijuana use) was significantly associated with a 0.17 annual percentage decline in cognitive processing speed only (TMTA) (β= -0.18, 95% CI: -0.36, -0.01; p=0.04).

CONCLUSIONS

Our findings suggest that marijuana use, particularly current use, may be associated with worse cognitive processing speed, but the magnitude of the estimates was not clinically meaningful.

Effects of Sleep Health on Cognitive Function in HIV+ and HIV- Adults

OBJECTIVES

People living with HIV (PLWH) are more likely to report sleep difficulties and cognitive deficits. While cognitive impairment associated with sleep problems have been found in healthy and medical populations, less is known about the effects of poor sleep health (SH) on cognition among PLWH. This study examined differences in cognitive performance among participants classified based upon their HIV status and reported SH.

METHODS

One hundred sixteen (N=116) adults recruited from the Greater Los Angeles community were administered a comprehensive cognitive test battery and completed a questionnaire about SH. Participants were classified into the following HIV/SH groups: [HIV+/good sleep health (SH+; n=34); HIV-/SH+ (n=32); HIV-/poor sleep health (SH-; n=18) and HIV+/SH- (n=32)].

RESULTS

For both HIV+ and HIV- individuals, poor SH was associated with lower cognitive performance, with the domains of learning and memory driving the overall relationship. The HIV+/SH- group had poorer scores in domains of learning and memory compared to the SH+ groups. Additionally, the HIV-/SH- group demonstrated poorer learning compared to the HIV-/SH+ group.

CONCLUSIONS

Our findings suggest that sleep problems within medical populations are relevant to cognitive functioning, highlighting the clinical and scientific importance of monitoring sleep health and cognition to help identify individuals at greatest risk of poor health outcomes. Longitudinal investigations using both objective and subjective measures of sleep are needed to determine the robustness of the current findings and the enduring effects of poor SH in the context of chronic disease. (JINS, 2018, 24, 1038-1046).

Confirmed marijuana use and lymphocyte count in black people living with HIV

BACKGROUND

Marijuana is a commonly used recreational substance with purported analgesic and mood enhancing properties. Many people living with HIV identify marijuana as a palliative substance. However, through its main psychoactive component, tetrahydrocannabinol (THC), is known to influence the immune system. The effects of marijuana use in people with HIV are still controversial, with very scant literature in Black adults.

METHODS

The current study determined the differences in the lymphocyte count, specifically the number cluster differentiation 4 and 8 (CD4+ and CD8+), among patients who urine drug tested negative for THC (n=70) and those who tested positive for THC (n=25). The sample included 95 Black people living with HIV, 51% female, with a mean age of 46±11years. Participants provided a urine sample for substance use testing and a trained researcher extracted clinical data from clinical charts on the day of appointment.

RESULTS

After adjusting for demographic and HIV-related covariates, THC-positive patients had significantly higher CD4+ and CD8+ counts than their THC-negative counterparts.

CONCLUSION

These results extend previous HIV-related immunity findings in an underrepresented group, and suggest that THC use does not reduce immune function as measured by CD count. Further research is warranted on the overall effects of THC on immune function in HIV positive patients.

HIV, Tat and dopamine transmission

Human Immunodeficiency Virus (HIV) is a progressive infection that targets the immune system, affecting more than 37 million people around the world. While combinatorial antiretroviral therapy (cART) has lowered mortality rates and improved quality of life in infected individuals, the prevalence of HIV associated neurocognitive disorders is increasing and HIV associated cognitive decline remains prevalent. Recent research has suggested that HIV accessory proteins may be involved in this decline, and several studies have indicated that the HIV protein transactivator of transcription (Tat) can disrupt normal neuronal and glial function. Specifically, data indicate that Tat may directly impact dopaminergic neurotransmission, by modulating the function of the dopamine transporter and specifically damaging dopamine-rich regions of the CNS. HIV infection of the CNS has long been associated with dopaminergic dysfunction, but the mechanisms remain undefined. The specific effect(s) of Tat on dopaminergic neurotransmission may be, at least partially, a mechanism by which HIV infection directly or indirectly induces dopaminergic dysfunction. Therefore, precisely defining the specific effects of Tat on the dopaminergic system will help to elucidate the mechanisms by which HIV infection of the CNS induces neuropsychiatric, neurocognitive and neurological disorders that involve dopaminergic neurotransmission. Further, this will provide a discussion of the experiments needed to further these investigations, and may help to identify or develop new therapeutic approaches for the prevention or treatment of these disorders in HIV-infected individuals.

Prevalence and correlates of marijuana use among HIV-seropositive and seronegative men in the Multicenter AIDS Cohort Study (MACS), 1984-2013

BACKGROUND

Marijuana use is common among HIV+ individuals, but few studies have examined long-term trends in prevalence and correlates of use.

METHODS

We evaluated trends (1984-2013) in the annual prevalence of current (past 6-month use) and daily (among current users) marijuana use and determined correlates of use among 2742 HIV-seropositive (HIV+) and 3172 HIV-seronegative (HIV-) men who have sex with men in the Multicenter AIDS Cohort Study (MACS). Poisson regression models were used to estimate prevalence ratios of marijuana use separately for the men who were enrolled before 2001 (early-cohort) and after 2001 (late-cohort).

RESULTS

Over the 29 years of the study, the prevalence of current marijuana use declined significantly, whereas daily use among users increased among all men in the early and late-cohorts. A HIV+ status was associated with higher prevalence of marijuana use among the men in the early-cohort (adjusted prevalence ratio [aPR] = 1.53, 95% confidence interval [CI]:1.42, 1.64, p = <0.0001), but not in the men in the late-cohort (aPR = 0.90, 95% CI: 0.79, 1.03, p = 0.1424). Alcohol use and cigarette smoking were being positively associated with marijuana use.

CONCLUSIONS

Although the annual prevalence of current marijuana use decreased significantly over time in the MACS, daily use among users increased significantly. Further, among the HIV+ men, our study did not show clinically significant adverse effects of marijuana use on highly active antiretroviral therapy use, CD4+ count, or HIV viral load.

Marijuana Use Impacts Midlife Cardiovascular Events in HIV-Infected Men

BACKGROUND

Marijuana use is prevalent among persons infected with human immunodeficiency virus (HIV), but its long-term effects on HIV disease progression and comorbidities are unknown.

METHODS

In this prospective study of 558 HIV-infected men enrolled in the Multicenter AIDS Cohort Study between 1990 and 2010, there were 182 HIV seroconverters and 376 with viral suppression on combination antiretroviral therapy (ART). Associations between heavy marijuana use and HIV disease markers or white blood cell (WBC) count were examined using mixed-effects and linear regression models. Effects of marijuana use on cardiovascular (CV) events and other endpoints were estimated using Kaplan-Meier and logistic regression analyses.

RESULTS

The median baseline age of participants was 41, 66% were white, 79% had education >12 years, and 20% reported heavy marijuana use at ≥50% of biannual visits during follow-up. Long-term heavy marijuana use showed no significant associations with viral load, CD4 counts, AIDS, cancer, or mortality in both cohorts but was independently associated with increased CV events between ages 40-60 after adjusting for age, tobacco smoking, viral load, and traditional risk factors (odds ratio [OR], 2.5; 95% confidence interval [CI] 1.3, 5.1). Marijuana and tobacco use were each independently associated with higher WBC counts in adjusted models (P < .01); the highest quartile of WBC counts (≥6500 cells/µL) was associated with increased CV events (OR 4.3; 95% CI, 1.5, 12.9).

CONCLUSIONS

Heavy marijuana use is a risk factor for CV disease in HIV-infected men ages 40-60, independent of tobacco smoking and traditional risk factors.

Cannabis Use, Medication Management and Adherence Among Persons Living with HIV

Cannabis is used to relieve nausea, trigger weight gain, and reduce pain among adults living with HIV; however, the relationship between its use and medication adherence and management is unclear. Participants (N = 107) were from an ongoing cohort study of community-dwelling HIV+ adults, stratified by cannabis (CB) use: HIV+/CB+ (n = 41) and HIV+/CB- (n = 66). CB+ participants either tested positive in a urine toxicology screen for THC or had a self-reported history of regular and recent use. HIV-status was provided by physician results and/or biomarker assessment. Adherence was measured via the Morisky scale and medication management was assessed via the Medication Management Test-Revised. After adjusting for gender, we found no association between cannabis use group and adherence nor medication management. The amount of cannabis used was also not associated with measures of adherence and management. Preliminary findings suggest that cannabis use may not adversely influence medication adherence/management among adults living with HIV.

High-intensity cannabis use and HIV clinical outcomes among HIV-positive people who use illicit drugs in Vancouver, Canada

BACKGROUND

Reforms to the legal status of medical and non-medical cannabis are underway in many jurisdictions, including Canada, as are renewed efforts to scale-up HIV treatment-as-prevention (TasP) initiatives. It has been suggested that high-intensity cannabis use may be associated with sub-optimal HIV treatment outcomes. Thus, using data from a setting with a community-wide treatment-as-prevention (TasP) initiative coinciding with increasing access to medical cannabis, we sought to investigate the possible impact of high-intensity cannabis use on HIV clinical outcomes.

METHODS

Data was derived from the ACCESS study, a prospective cohort of HIV-positive people who use illicit drugs (PWUD) in Vancouver, Canada. Cohort data was confidentially linked to comprehensive clinical profiles, including records of all antiretroviral therapy (ART) dispensations and longitudinal plasma HIV-1 RNA viral load (VL) monitoring. We used generalized estimating equations (GEEs) to estimate the longitudinal bivariable and multivariable relationships between at least daily cannabis use and two key clinical outcomes: overall engagement in ART care, and achieving a non-detectable VL among ART-exposed participants.

RESULTS

Between December 2005 and June 2015, 874 HIV-positive PWUD (304 [35%] non-male) were included in this study. In total, 788 (90%) were engaged in HIV care at least once over the study period, of whom 670 (85%) achieved non-detectable VL at least once. In multivariable analyses, ≥ daily cannabis use did not predict lower odds of ART care (Adjusted Odds Ratio [AOR]: 1.02, 95% confidence interval [CI]: 0.77-1.36) or VL non-detectability among ART-exposed (AOR: 0.96, 95% CI: 0.75-1.21). Upon testing for potential interactions, ≥ daily cannabis use was found to be negatively associated with ART engagement during periods of binge alcohol use (p<0.05).

CONCLUSION

With the exception of frequent cannabis use during periods of binge alcohol use, our results showed no statistically significant impact of daily cannabis use on the likelihood of ART care or VL non-detectability among ART-exposed HIV-positive PWUD. These findings are reassuring in light of the impending legalization of cannabis in Canada and ongoing efforts to expand TasP initiatives.

Marijuana effects on changes in brain structure and cognitive function among HIV+ and HIV- adults

BACKGROUND

The current study examined the independent and interactive effects of HIV and marijuana (MJ) use on brain structure and cognitive function among a sample of HIV-positive (HIV+) and HIV-negative (HIV-) individuals.

METHODS

Participants (HIV+, n=48; HIV-, n=29) individuals underwent cognitive testing, questionnaires about substance use, and brain MRI. The HIV+ group was clinically stable based upon current plasma CD4 count, 50% had undetectable viral load (i.e.,<20 copies/mL), and all were on a stable regimen of cART.

RESULTS

For HIV+ and HIV- participants, higher levels of MJ use were associated with smaller volumes in the entorhinal cortex and fusiform gyrus. HIV status (but not MJ use) was associated with cingulate thickness, such that HIV+ participants evidenced smaller thickness of the cingulate, as compared to HIV- controls. Regarding neurocognitive functioning, there was a HIV*MJ interactive effect on global cognition, such that when the amount of MJ use was less than 1.43g per week, the HIV- group displayed significantly better neurocognitive performance than the HIV+ group (t=3.14, p=0.002). However, when MJ use reached 1.43g per week, there were no significant HIV group differences in global cognitive performance (t=1.39, p=0.168).

CONCLUSIONS

Our results show independent and interactive effects of HIV and MJ on brain structure and cognition. However, our results do not support that HIV+ MJ users are at greater risk for adverse brain or cognitive outcomes compared to HIV- MJ users.

Marijuana use and viral suppression in persons receiving medical care for HIV-infection

BACKGROUND

Marijuana use is common among persons living with HIV (PLWH), but studies on its effect on HIV clinical outcomes are limited.

OBJECTIVES

We determined the association between marijuana use and HIV viral suppression among PLWH.

METHODS

Data came from five repeated cross-sections (2009-2013) of the Florida Medical Monitoring Project, a population-based sample of PLWH in Florida. Data were obtained via interview and medical record abstraction (MRA). Weighted logistic regression models were used to determine the association between marijuana use (past 12 months) and durable viral suppression (HIV-1 RNA value of ≤ 200 copies/milliliter in all measurements within the past 12 months).

RESULTS

Of the 1,902 PLWH receiving antiretroviral therapy, completed an interview, and had a linked MRA, 20% reported marijuana use (13% less than daily and 7% daily use) and 73% achieved durable viral suppression. In multivariable analysis, marijuana use was not significantly associated with durable viral suppression in daily [Adjusted Odds Ratio (AOR): 0.87, 95% confidence interval (CI): 0.58, 1.33] or in less than daily [AOR: 0.83, 95% CI: 0.51, 1.37] users as compared to non-users when adjusting for sociodemographic factors, time since HIV diagnosis, depressive symptoms, alcohol, cigarette and other substance use.

CONCLUSION

In this sample of PLWH receiving medical care in Florida, there was no statistically significant association between marijuana use and viral suppression. However, as the limits of the confidence intervals include effects that may be considered to be clinically important, there is a need for additional evidence from other samples and settings that include more marijuana users.