Drugs and immunity: cannabinoids and their role in decreased resistance to infectious disease

Development of N-(1-Adamantyl)benzamides as Novel Anti-Inflammatory Multitarget Agents Acting as Dual Modulators of the Cannabinoid CB2 Receptor and Fatty Acid Amide Hydrolase

Cannabinoid type 2 receptor (CB2R), belonging to the endocannabinoid system, is overexpressed in pathologies characterized by inflammation, and its activation counteracts inflammatory states. Fatty acid amide hydrolase (FAAH) is an enzyme responsible for the degradation of the main endocannabinoid anandamide; thus, the simultaneous CB2R activation and FAAH inhibition may be a synergistic anti-inflammatory strategy. Encouraged by principal component analysis (PCA) data identifying a wide chemical space shared by CB2R and FAAH ligands, we designed a small library of adamantyl-benzamides, as potential dual agents, CB2R agonists, and FAAH inhibitors. The new compounds were tested for their CB2R affinity/selectivity and CB2R and FAAH activity. Derivatives 13, 26, and 27, displaying the best pharmacodynamic profile as CB2R full agonists and FAAH inhibitors, decreased pro-inflammatory and increased anti-inflammatory cytokines production. Molecular docking simulations complemented the experimental findings by providing a molecular rationale behind the observed activities. These multitarget ligands constitute promising anti-inflammatory agents.

Associations between prenatal and postnatal substance exposure and salivary C-reactive protein in early childhood

BACKGROUND

Exposure to tobacco and cannabis during developmental periods of enhanced vulnerability (e.g., in utero and early childhood) may have long-lasting effects on child health. One potential mechanism underlying these associations is the alteration of inflammatory pathways. Using data from a longitudinal study of mother/child dyads, we examined the adjusted and combined associations of prenatal and postnatal tobacco and cannabis exposure with inflammation in early childhood. Furthermore, we explored the relations between different measures of exposure, partly reflecting differences in timing, dose, and level of fetal exposure (e.g., self-report vs. biomarker), and inflammation. Finally, we explored child sex as a moderator of prenatal and postnatal tobacco and cannabis exposure and inflammation.

METHOD

Women were recruited from a local hospital during their first prenatal appointment. Repeated assessments were conducted at each trimester, at birth, and when children were 2, 9, 16, 24, 36, and 60 months old (N = 215; 112 female children). To evaluate associations with different measurement approaches, prenatal tobacco and cannabis exposure were assessed using: 1) continuous dose-response variables of maternal self-reported tobacco and cannabis use during each trimester to assess associations with timing and severity of exposure, 2) categorization of children into exposure groups based on drugs and metabolites present in infant meconium reflecting later pregnancy fetal exposure, and 3) categorization into exposure groups using a combination of maternal self-report data and biomarker data derived from maternal saliva samples and infant meconium taking advantage of multiple methods of assessment to examine group differences. Postnatal exposure to tobacco (assessed using child salivary cotinine) and cannabis (assessed using maternal self-reported average joints smoked per day) was measured at each infancy/early childhood assessment. Adjusted pre- and postnatal exposure associations with child inflammation were assessed by including both measures as predictor variables in linear regression models predicting child salivary C-reactive protein (CRP) concentrations at 60 months. Interactions between pre- and postnatal exposure variables were then modeled to investigate the combined relations between pre- and postnatal substance exposure with child salivary CRP concentrations at 60 months.

RESULTS

Adjusting for postnatal exposure variables, there was a significant interaction between the average daily cigarettes and the average daily cannabis joints smoked during the third trimester predicting salivary CRP concentrations in early childhood. At high tobacco exposure, the effect of cannabis on CRP concentrations was negligible, whereas at low tobacco exposure, the effect of cannabis exposure on CRP concentrations was positive. Adjusting for postnatal tobacco and cannabis exposure, children for whom meconium data indicated co-exposure to tobacco and cannabis showed approximately 43% lower CRP concentrations at age 60 months compared to children with no exposure. However, when mother/child dyads were categorized based on a combination of maternal self-report data and biomarker data from saliva samples and infant meconium, there were no differences in salivary CRP concentrations at age 60 months across the three groups (no prenatal exposure, prenatal tobacco exposure only, prenatal co-exposure to tobacco and cannabis), controlling for postnatal associations. Regardless of the measurement method used to assess prenatal exposures in adjusted analyses, prenatal tobacco exposure alone did not predict CRP concentrations in early childhood, nor did postnatal tobacco exposure. Among boys, postnatal cannabis exposure was associated with higher concentrations of CRP at age 60 months, controlling for prenatal exposure relations. There were no significant combined associations of pre- and postnatal exposure with CRP concentrations.

CONCLUSION

This study expands upon known relations between prenatal and postnatal substance exposure and immunological outcomes in early childhood, underscoring the importance of assessing cannabis exposure during gestation and early life in combination with tobacco exposure.

The Therapeutic Potential of the Endocannabinoid System in Age-Related Diseases

The endocannabinoid system (ECS) dynamically regulates many aspects of mammalian physiology. ECS has gained substantial interest since growing evidence suggests that it also plays a major role in several pathophysiological conditions due to its ability to modulate various underlying mechanisms. Furthermore, cannabinoids, as components of the cannabinoid system (CS), have proven beneficial effects such as anti-inflammatory, immunomodulatory, neuromodulatory, antioxidative, and cardioprotective effects. In this comprehensive review, we aimed to describe the complex interaction between CS and most common age-related diseases such as neuro-degenerative, oncological, skeletal, and cardiovascular disorders, together with the potential of various cannabinoids to ameliorate the progression of these disorders. Since chronic inflammation is postulated as the pillar of all the above-mentioned medical conditions, we also discuss in this paper the potential of CS to ameliorate aging-associated immune system dysregulation.

Anti-Microbial Activity of Phytocannabinoids and Endocannabinoids in the Light of Their Physiological and Pathophysiological Roles

Antibiotic resistance has become an increasing challenge in the treatment of various infectious diseases, especially those associated with biofilm formation on biotic and abiotic materials. There is an urgent need for new treatment protocols that can also target biofilm-embedded bacteria. Many secondary metabolites of plants possess anti-bacterial activities, and especially the phytocannabinoids of the Cannabis sativa L. varieties have reached a renaissance and attracted much attention for their anti-microbial and anti-biofilm activities at concentrations below the cytotoxic threshold on normal mammalian cells. Accordingly, many synthetic cannabinoids have been designed with the intention to increase the specificity and selectivity of the compounds. The structurally unrelated endocannabinoids have also been found to have anti-microbial and anti-biofilm activities. Recent data suggest for a mutual communication between the endocannabinoid system and the gut microbiota. The present review focuses on the anti-microbial activities of phytocannabinoids and endocannabinoids integrated with some selected issues of their many physiological and pharmacological activities.

Examining the Use of Antidepressants for Adolescents with Depression/Anxiety Who Regularly Use Cannabis: A Narrative Review

Depression and anxiety disorders are two of the most common and growing mental health concerns in adolescents. Consequently, antidepressant medication (AD) use has increased widely during the last decades. Several classes of antidepressants are used mainly to treat depression, anxiety, and obsessive-compulsive disorders by targeting relevant brain neurochemical pathways. Almost all randomized clinical trials of antidepressants examined patients with no concomitant medications or drugs. This does not address the expected course of therapy and outcome in cannabis users. Cannabis is the most commonly used illicit substance globally. Substantial changes in its regulation are recently taking place. Many countries and US states are becoming more permissive towards its medical and recreational use. The psychological and physiological effects of cannabis (mainly of its major components, tetrahydrocannabinol (THC) and cannabidiol (CBD)) have been extensively characterized. Cannabis use can be a risk factor for depressive and anxiety symptoms, but some constituents or mixtures may have antidepressant and/or anxiolytic potential. The aim of this literature review is to explore whether simultaneous use of AD and cannabis in adolescence can affect AD treatment outcomes. Based on the current literature, it is reasonable to assume that antidepressants are less effective for adolescents with depression/anxiety who frequently use cannabis. The mechanisms of action of antidepressants and cannabis point to several similarities and conjunctions that merit future investigation regarding the potential effectiveness of antidepressants among adolescents who consume cannabis regularly.

Antimicrobial and Antiviral (SARS-CoV-2) Potential of Cannabinoids and Cannabis sativa: A Comprehensive Review

Antimicrobial resistance has emerged as a global health crisis and, therefore, new drug discovery is a paramount need. Cannabis sativa contains hundreds of chemical constituents produced by secondary metabolism, exerting outstanding antimicrobial, antiviral, and therapeutic properties. This paper comprehensively reviews the antimicrobial and antiviral (particularly against SARS-CoV-2) properties of C. sativa with the potential for new antibiotic drug and/or natural antimicrobial agents for industrial or agricultural use, and their therapeutic potential against the newly emerged coronavirus disease (COVID-19). Cannabis compounds have good potential as drug candidates for new antibiotics, even for some of the WHO's current priority list of resistant pathogens. Recent studies revealed that cannabinoids seem to have stable conformations with the binding pocket of the Mpro enzyme of SARS-CoV-2, which has a pivotal role in viral replication and transcription. They are found to be suppressive of viral entry and viral activation by downregulating the ACE2 receptor and TMPRSS2 enzymes in the host cellular system. The therapeutic potential of cannabinoids as anti-inflammatory compounds is hypothesized for the treatment of COVID-19. However, more systemic investigations are warranted to establish the best efficacy and their toxic effects, followed by preclinical trials on a large number of participants.

Parkinson's disease related alterations in cannabinoid transmission

Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic (DAergic) neurons of the substantia nigra pars compacta (SNc) by neurodegeneration. Recent findings in animal models of PD propose tonic inhibition of the remaining DA neurons through GABA release from reactive glial cells. Movement dysfunctions could be ameliorated by promotion of activity in dormant DA cells. The endocannabinoid system (ECS) is extensively present in basal ganglia (BG) and is known as an indirect modulator of DAergic neurotransmission, thus drugs designed to target this system have shown promising therapeutic potential in PD patients. Interestingly, down/up-regulation of cannabinoid receptors (CBRs) varies across the different stages of PD, suggesting that some of the motor/ non-motor deficits may be related to changes in CBRs. Determination of the profile of changes of these receptors across the different stages of PD as well as their neural distribution within the BG could improve understanding of PD and identify pathways important in disease pathobiology. In this review, we focus on temporal and spatial alterations of CBRs during PD in the BG. At present, as inconclusive, but suggestive results have been obtained, future investigations should be conducted to extend preclinical studies examining CBRs changes within each stage in controlled clinical trials in order to determine the potential of targeting CBRs in management of PD.

Coronavirus Disease 2019 (COVID-19) Crisis: Losing Our Immunity When We Need It the Most

The ongoing coronavirus disease 2019 (COVID-19) crisis has led to a new socioeconomic reality with the acquisition of novel habits. Measures imposed by governments and health authorities such as confinement and lockdown have had important consequences, including mental health problems, economic crisis, and social isolation. Combined with newly acquired habits such as hand washing, sanitization, and face masks, these have all directly and indirectly led to reduced immunity. Such effects on the immune system not only impact the epidemiological profile with respect to COVID-19 and other infectious diseases but also limit the efficacy of the ongoing anti-COVID-19 vaccination campaign. Therefore, there is a need to review these approaches and optimize measures towards better population immunity, which is much needed during such an epidemic.

Cannabis, the Endocannabinoid System and Immunity-the Journey from the Bedside to the Bench and Back

The Cannabis plant contains numerous components, including cannabinoids and other active molecules. The phyto-cannabinoid activity is mediated by the endocannabinoid system. Cannabinoids affect the nervous system and play significant roles in the regulation of the immune system. While Cannabis is not yet registered as a drug, the potential of cannabinoid-based medicines for the treatment of various conditions has led many countries to authorize their clinical use. However, the data from basic and medical research dedicated to medical Cannabis is currently limited. A variety of pathological conditions involve dysregulation of the immune system. For example, in cancer, immune surveillance and cancer immuno-editing result in immune tolerance. On the other hand, in autoimmune diseases increased immune activity causes tissue damage. Immuno-modulating therapies can regulate the immune system and therefore the immune-regulatory properties of cannabinoids, suggest their use in the therapy of immune related disorders. In this contemporary review, we discuss the roles of the endocannabinoid system in immunity and explore the emerging data about the effects of cannabinoids on the immune response in different pathologies. In addition, we discuss the complexities of using cannabinoid-based treatments in each of these conditions.

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.

Therapeutic Cannabis and Endocannabinoid Signaling System Modulator Use in Otolaryngology Patients

Objectives

1) review benefits and risks of cannabis use, with emphasis on otolaryngic disease processes; 2) define and review the endocannabinoid signaling system (ESS); and 3) review state and federal regulations for the use and research of cannabis and ESS modulators.

Methods

This manuscript is a review of the current literature relevant to the stated objectives.

Results

Cannabis (marijuana) use is increasing. It is the most widely used illicit substance in the world. There is increasing interest in its therapeutic potential due to changing perceptions, new research, and legislation changes controlling its use. The legal classification of cannabis is complicated due to varied and conflicting state and federal laws. There are currently two synthetic cannabinoid drugs that are FDA approved. Current indications for use include chemotherapy‐related nausea and vomiting, cachexia, and appetite loss. Research has demonstrated potential benefit for use in many other pathologies including pain, inflammatory states, and malignancy. Data exists demonstrating potential antineoplastic benefit in oral, thyroid, and skin cancers.

Conclusions

ESS modulators may play both a causal and therapeutic role in several disorders seen in otolaryngology patients. The use of cannabis and cannabinoids is not without risk. There is a need for further research to better understand both the adverse and therapeutic effects of cannabis use. With increasing rates of consumption, elevated public awareness, and rapidly changing legislation, it is helpful for the otolaryngologist to be aware of both the adverse manifestations of use and the potential therapeutic benefits when talking with patients.

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.

Maternal marijuana use, adverse pregnancy outcomes, and neonatal morbidity

BACKGROUND

The Eunice Kennedy Shriver National Institute of Child Health and Human Development Stillbirth Collaborative Research Network previously demonstrated an association between stillbirth and maternal marijuana use as defined by the presence of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid in the umbilical cord homogenate. However, the relationship between marijuana use and perinatal complications in live births is uncertain.

OBJECTIVE

Our aim was to examine if maternal marijuana use is associated with increased odds of adverse pregnancy outcomes and neonatal morbidity among live-born controls in the Stillbirth Collaborative Research Network cohort.

STUDY DESIGN

We conducted a secondary analysis of singleton, live-born controls in the Stillbirth Collaborative Research Network data set. Marijuana use was measured by self-report and/or the presence of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid in umbilical cord homogenate. Tobacco use was measured by self-report and/or presence of any cotinine in maternal serum. Adverse pregnancy outcome was a composite of small for gestational age, spontaneous preterm birth resulting from preterm labor with or without intact membranes, and hypertensive disorders of pregnancy. Neonatal morbidity included neonatal intensive care unit admission and composite neonatal morbidity (pulmonary morbidity, necrotizing enterocolitis, seizures, retinopathy of prematurity, infection morbidity, anemia requiring blood transfusion, neonatal surgery, hyperbilirubinemia, neurological morbidity, or death prior to hospital discharge). Effect of maternal marijuana use on the probability of an adverse outcome was estimated using weighted methodology to account for oversampling in the original study. 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid cord homogenate analysis was performed in the subset of women for whom biospecimens were available. Comparisons using logistic modeling, χ², and t tests were weighted to account for oversampling of preterm births and non-Hispanic blacks. Results are reported as weighted percent and unweighted frequencies.

RESULTS

Maternal marijuana use was identified in 2.7% (unweighted frequency 48/1610) of live births. Use was self-reported by 1.6% (34/1610) and detected by 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid in cord homogenate for 1.9% (17/897), n = 3 overlapping. Rate of tobacco use was 12.9% (217/1610), with 10.7% (167/1607) by self-report and 9.5% (141/1313) by serum cotinine. The composite adverse pregnancy outcome was not significantly increased in women with marijuana use compared to nonusers (31.2% vs 21.2%; P = .14). After adjustment for tobacco, clinical, and socioeconomic factors, marijuana use was not associated with the composite adverse pregnancy outcome (adjusted odds ratio, 1.29; 95% confidence interval, 0.56-2.96). Similarly, among women with umbilical cord homogenate and serum cotinine data (n = 765), marijuana use was not associated with adverse pregnancy outcomes (adjusted odds ratio, 1.02; 95% confidence interval, 0.18-5.66). Neonatal intensive care unit admission rates were not statistically different between groups (16.9% users vs 9.5% nonusers, P = .12). Composite neonatal morbidity or death was more frequent among neonates of mothers with marijuana use compared to nonusers (14.1% vs 4.5%; P = .002). In univariate comparisons, the components of the composite outcome that were more frequent in neonates of marijuana users were infection morbidity (9.8% vs 2.4%; P < .001) and neurologic morbidity (1.4% vs 0.3%; P = .002). After adjustment for tobacco, race, and other illicit drug use, marijuana use was still associated with composite neonatal morbidity or death (adjusted odds ratio, 3.11; 95% confidence interval, 1.40-6.91).

CONCLUSION

Maternal marijuana use was not associated with a composite of small for gestational age, spontaneous preterm birth, or hypertensive disorders of pregnancy. However, it was associated with an increased risk of neonatal morbidity.

Endo-cannabinoids system and the toxicity of cannabinoids with a biotechnological approach

Cannabinoids have shown diverse and critical effects on the body systems, which alter the physiological functions. Synthetic cannabinoids are comparatively innovative misuse drugs with respect to their nature of synthesis. Synthetic cannabinoids therapy in healthy, chain smokers, and alcoholic individuals cause damage to the immune and nervous system, eventually leading to intoxication throughout the body. Relevant studies were retrieved using major electronic databases such as PubMed, EMBASE, Medline, Scopus, and Google Scholar. The extensive use of Cannabis Sativa L. (C. Sativa) and its derivatives/analogues such as the nonpsychoactive dimethyl heptyl homolog (CBG-DMH), and tetrahydrocannabivarin (THCV) amongst juveniles and adults have been enhanced in recent years. Cannabinoids play a crucial role in the induction of respiratory, reproductive, immune and carcinogenic effects; however, potential data about mutagenic and developmental effects are still insufficient. The possible toxicity associated with the prolong use of cannabinoids acts as a tumor promoter in animal models and humans. Particular synthetic cannabinoids and analogues have low affinity for CB1 or CB2 receptors, while some synthetic members like Δ9-THC have high affinity towards these receptors. Cannabinoids and their derivatives have a direct or indirect association with acute and long-term toxicity. To reduce/attenuate cannabinoids toxicity, pharmaceutical biotechnology and cloning methods have opened a new window to develop cannabinoids encoding the gene tetrahydrocannabinolic acid (THCA) synthase. Plant revolution and regeneration hindered genetic engineering in C. Sativa. The genetic culture suspension of C. Sativa can be transmuted by the use of Agrobacterium tumefaciens to overcome its toxicity. The main aim of the present review was to collect evidence of the endo-cannabinoid system (ECS), cannabinoids toxicity, and the potential biotechnological approach of cannabinoids synthesis.

Lifetime marijuana use and sexually transmitted infection history in a sample of Black college students

BACKGROUND

Sexually transmitted infections (STIs) and marijuana use are more prevalent in African Americans/Blacks (Blacks) than any other ethnicity in the United States. Given the significant health care costs and deleterious health correlates of using marijuana or contracting a STI, it is imperative to examine their association, especially in the vulnerable and underrepresented group of young adult Blacks.

PURPOSE

The current study examines the association between lifetime marijuana use on history of STI diagnosis in a sample of Black college students.

RESULTS

Approximately 81% of the 213 participants were female, with approximately 81% also being 21years of age or younger. Alcohol (88%) led the prevalence of substances ever used, followed by marijuana (75%), and cigarettes (57%). When including demographic and substance use covariates, lifetime marijuana use (AOR=2.51; 95% CIs, 1.01, 6.21) and age (AOR=2.72; 95% CIs, 1.32, 5.64) were associated with history of STI.

CONCLUSION

These findings will inform intervention and prevention methods used to reduce STI prevalence and marijuana use among Black young adults. Both epidemiological and biological foundations will be discussed.

Exposure of Adolescent Mice to Delta-9-Tetrahydrocannabinol Induces Long-Lasting Modulation of Pro- and Anti-Inflammatory Cytokines in Hypothalamus and Hippocampus Similar to that Observed for Peripheral Macrophages

Cannabis use is frequent among adolescents. Its main component, delta-9-tetrahydrocannabinol (THC), affects the immune system. We recently demonstrated that chronic exposure of adolescent mice to THC suppressed immunity immediately after treatment but that after a washout period THC induced a long-lasting opposite modulation towards a proinflammatory and T-helper-1 phenotype in adulthood. The main objective of this study was to investigate whether the same effect was also present in brain regions such as the hypothalamus and hippocampus. Thirty-three-day-old adolescent and 80-day-old adult male mice were used. Acute THC administration induced a similar reduction of macrophage proinflammatory cytokines and an IL-10 increase in adult and adolescent mice. THC did not affect brain cytokines in adult mice, but a proinflammatory cytokine decrease was evident in the adolescent brain. A similar effect was present in the hypothalamus and hippocampus after 10 days' THC administration. In contrast, when brain cytokines were measured 47 days after the final THC administration, we observed an inverted effect in adult mice treated as adolescents, i.e., IL-1β and TNF-α increased and IL-10 decreased, indicating a shift toward neuroinflammation. These data suggest that THC exposure in adolescence has long-lasting effects on brain cytokines that parallel those present in the periphery. This modulation may affect vulnerability to immune and behavioural diseases in adulthood.

Chronic Δ⁹-tetrahydrocannabinol administration may not attenuate simian immunodeficiency virus disease progression in female rhesus macaques

Persons living with HIV/AIDS (PLWHA) frequently use cannabinoids, either recreationally by smoking marijuana or therapeutically (delta-9-tetrahydrocannabinol; Δ(9)-THC dronabinol). Previously, we demonstrated that chronic Δ(9)-THC administration decreases early mortality in male simian immunodeficiency virus (SIV)-infected macaques. In this study, we sought to examine whether similar protective effects resulted from chronic cannabinoid administration in SIV-infected female rhesus macaques. Clinical and viral parameters were evaluated in eight female rhesus macaques that received either Δ(9)-THC (0.18-0.32 mg/kg, intramuscularly, twice daily) or vehicle (VEH) starting 28 days prior to intravenous inoculation with SIVmac251. SIV disease progression was assessed by changes in body weight, mortality, viral levels in plasma and mucosal sites, and lymphocyte subsets. In contrast to our results in male animals, chronic Δ(9)-THC did not protect SIV-infected female rhesus macaques from early mortality. Markers of SIV disease, including viral load and CD4(+)/CD8(+) ratio, were not altered by Δ(9)-THC compared to control females; however, females that received chronic Δ(9)-THC did not gain as much weight as control animals. In addition, Δ(9)-THC administration increased total CXCR4 expression in both peripheral and duodenal CD4(+) and CD8(+) T lymphocytes prior to SIV inoculation. Although protection from early mortality was not evident, chronic Δ(9)-THC did not affect clinical markers of SIV disease progression. The contrasting effects of chronic Δ(9)-THC in males versus females remain to be explained, but highlight the need for further studies to explore the sex-dependent effects of Δ(9)-THC and other cannabinoids on the HIV disease course and their implications for virus transmission.

Influence of noninjecting and injecting drug use on mortality, retention in the cohort, and antiretroviral therapy, in participants in the Swiss HIV Cohort Study

OBJECTIVES

We studied the influence of noninjecting and injecting drug use on mortality, dropout rate, and the course of antiretroviral therapy (ART), in the Swiss HIV Cohort Study (SHCS).

METHODS

Cohort participants, registered prior to April 2007 and with at least one drug use questionnaire completed until May 2013, were categorized according to their self-reported drug use behaviour. The probabilities of death and dropout were separately analysed using multivariable competing risks proportional hazards regression models with mutual correction for the other endpoint. Furthermore, we describe the influence of drug use on the course of ART.

RESULTS

A total of 6529 participants (including 31% women) were followed during 31 215 person-years; 5.1% participants died; 10.5% were lost to follow-up. Among persons with homosexual or heterosexual HIV transmission, noninjecting drug use was associated with higher all-cause mortality [subhazard rate (SHR) 1.73; 95% confidence interval (CI) 1.07-2.83], compared with no drug use. Also, mortality was increased among former injecting drug users (IDUs) who reported noninjecting drug use (SHR 2.34; 95% CI 1.49-3.69). Noninjecting drug use was associated with higher dropout rates. The mean proportion of time with suppressed viral replication was 82.2% in all participants, irrespective of ART status, and 91.2% in those on ART. Drug use lowered adherence, and increased rates of ART change and ART interruptions. Virological failure on ART was more frequent in participants who reported concomitant drug injections while on opiate substitution, and in current IDUs, but not among noninjecting drug users.

CONCLUSIONS

Noninjecting drug use and injecting drug use are modifiable risks for death, and they lower retention in a cohort and complicate ART.

Association between exposure to HSV1 and cognitive functioning in a general population of adolescents. The TRAILS study

BACKGROUND

Infections with different herpes viruses have been associated with cognitive functioning in psychiatric patients and healthy adults. The aim of this study was to find out whether antibodies to different herpes viruses are prospectively associated with cognitive functioning in a general adolescent population.

METHODS

This study was performed in TRAILS, a large prospective general population cohort (N = 1084, 54% female, mean age 16.2 years (SD 0.6)). At age 16, immunoglobulin G antibodies against HSV1, HSV2, CMV and EBV were measured next to high sensitive C-Reactive Protein (hsCRP). Two years later, immediate memory and executive functioning were assessed using the 15 words task and the self ordered pointing task. Multiple linear regression analysis with bootstrapping was performed to study the association between viral infections and cognitive function, adjusting for gender, socioeconomic status, ethnicity, and cannabis use.

RESULTS

Presence of HSV1 antibodies was associated with memory function ((B = -0.272, 95% CI = -0.556 to -0.016, p = 0.047)), while the association with executive functioning did not reach statistical significance (B = 0.560, 95% CI is -0.053 to 1.184, p = 0.075). The level of HSV1 antibodies was associated with both memory function (B = -0.160, 95% CI = -0.280 to -0.039, p = 0.014) and executive functioning (B = 0.296, 95% CI = 0.011 to 0.578, p = 0.046). Other herpes viruses and hsCRP were not associated with cognitive functioning.

CONCLUSIONS

Both presence and level of HSV1 antibodies are prospectively associated with reduced cognitive performance in a large cohort of adolescents.

Δ⁹-Tetrahydrocannabinol-induced anti-inflammatory responses in adolescent mice switch to proinflammatory in adulthood

Marijuana abuse is prominent among adolescents. Although Δ(9)-THC, one of its main components, has been demonstrated to modulate immunity in adults, little is known about its impact during adolescence on the immune system and the long-lasting effects in adulthood. We demonstrate that 10 days of Δ(9)-THC treatment induced a similar alteration of macrophage and splenocyte cytokines in adolescent and adult mice. Immediately at the end of chronic Δ(9)-THC, a decrease of proinflammatory cytokines IL- 1β and TNF-α and an increase of anti-inflammatory cytokine IL-10 production by macrophages were present as protein and mRNA in adolescent and adult mice. In splenocytes, Δ(9)-THC modulated Th1/Th2 cytokines skewing toward Th2: IFN-γ was reduced, and IL-4 and IL-10 increased. These effects were lost in adult animals, 47 days after the last administration. In contrast, in adult animals treated as adolescents, a perturbation of immune responses, although in an opposite direction, was present. In adults treated as adolescents, a proinflammatory macrophage phenotype was observed (IL-1β and TNF-α were elevated; IL-10 decreased), and the production of Th cytokines was blunted. IgM titers were also reduced. Corticosterone concentrations indicate a long-lasting dysregulation of HPA in adolescent mice. We measured blood concentrations of Δ(9)-THC and its metabolites, showing that Δ(9)-THC plasma levels in our mice are in the order of those achieved in human heavy smokers. Our data demonstrate that Δ(9)-THC in adolescent mice triggers immune dysfunctions that last long after the end of abuse, switching the murine immune system to proinflammatory status in adulthood.

CB2 receptor deficiency increases amyloid pathology and alters tau processing in a transgenic mouse model of Alzheimer's disease

The endocannabinoid CB2 receptor system has been implicated in the neuropathology of Alzheimer's disease (AD). In order to investigate the impact of the CB2 receptor system on AD pathology, a colony of mice with a deleted CB2 receptor gene, CNR2, was established on a transgenic human mutant APP background for pathological comparison with CB2 receptor-sufficient transgenic mice. J20 APP (PDGFB-APPSwInd) mice were bred over two generations with CNR2(-/-) (Cnr2(tm1Dgen)/J) mice to produce a colony of J20 CNR2(+/+) and J20 CNR2(-/-) mice. Seventeen J20 CNR2(+/+) mice (12 females, 5 males) and 16 J20 CNR2(-/-) mice (11 females, 5 males) were killed at 12 months, and their brains were interrogated for AD-related pathology with both biochemistry and immunocytochemistry (ICC). In addition to amyloid-dependent endpoints such as soluble Aβ production and plaque deposition quantified with 6E10 staining, the effect of CB2 receptor deletion on total soluble mouse tau production was assayed by using a recently developed high-sensitivity assay. Results revealed that soluble Aβ42 and plaque deposition were significantly increased in J20 CNR2(-/-) mice relative to CNR2(+/+) mice. Microgliosis, quantified with ionized calcium-binding adapter molecule 1 (Iba-1) staining, did not differ between groups, whereas plaque associated microglia was more abundant in J20 CNR2(-/-) mice. Total tau was significantly suppressed in J20 CNR2(-/-) mice relative to J20 CNR2(+/+) mice. The results confirm the constitutive role of the CB2 receptor system both in reducing amyloid plaque pathology in AD and also support tehpotential of cannabinoid therapies targeting CB2 to reduce Aβ; however, the results suggest that interventions may have a divergent effect on tau pathology.

Association of marijuana smoking with oropharyngeal and oral tongue cancers: pooled analysis from the INHANCE consortium

BACKGROUND

The incidence of oropharyngeal and oral tongue cancers has increased over the last 20 years which parallels increased use of marijuana among individuals born after 1950.

METHODS

A pooled analysis was conducted comprising individual-level data from nine case-control studies from the United States and Latin America in the INHANCE consortium. Self-reported information on marijuana smoking, demographic, and behavioral factors was obtained from 1,921 oropharyngeal cases, 356 oral tongue cases, and 7,639 controls.

RESULTS

Compared with never marijuana smokers, ever marijuana smokers had an elevated risk of oropharyngeal [adjusted OR (aOR), 1.24; 95% confidence interval (CI): 1.06-1.47] and a reduced risk of oral tongue cancer (aOR, 0.47; 95% CI, 0.29, 0.75). The risk of oropharyngeal cancer remained elevated among never tobacco and alcohol users. The risk of oral tongue cancer was reduced among never users of tobacco and alcohol. Sensitivity analysis adjusting for potential confounding by HPV exposure attenuated the association of marijuana use with oropharyngeal cancer (aOR, 0.99; 95% CI, 0.71-1.25), but had no effect on the oral tongue cancer association.

CONCLUSIONS

These results suggest that the association of marijuana use with head and neck carcinoma may differ by tumor site.

IMPACT

The associations of marijuana use with oropharyngeal and oral tongue cancer are consistent with both possible pro- and anticarcinogenic effects of cannabinoids. Additional work is needed to rule out various sources of bias, including residual confounding by HPV infection and misclassification of marijuana exposure.

CB₂ receptor deficiency increases amyloid pathology and alters tau processing in a transgenic mouse model of Alzheimer's disease

The endocannabinoid CB₂ receptor system has been implicated in the neuropathology of Alzheimer's disease (AD). In order to investigate the impact of the CB₂ receptor system on AD pathology, a colony of mice with a deleted CB₂ receptor gene, CNR2, was established on a transgenic human mutant APP background for pathological comparison with CB₂ receptor-sufficient transgenic mice. J20 APP (PDGFB-APPSwInd) mice were bred over two generations with CNR2⁻/⁻ (Cnr2(tm1Dgen)/J) mice to produce a colony of J20 CNR2⁺/⁺ and J20 CNR2⁻/⁻ mice. Seventeen J20 CNR2⁺/⁺ mice (12 females, 5 males) and 16 J20 CNR2⁻/⁻ mice (11 females, 5 males) were killed at 12 months, and their brains were interrogated for AD-related pathology with both biochemistry and immunocytochemistry (ICC). In addition to amyloid-dependent endpoints such as soluble Aβ production and plaque deposition quantified with 6E10 staining, the effect of CB2 receptor deletion on total soluble mouse tau production was assayed by using a recently developed high-sensitivity assay. Results revealed that soluble Aβ42 and plaque deposition were significantly increased in J20 CNR2⁻/⁻ mice relative to CNR2⁺/⁺ mice. Microgliosis, quantified with ionized calcium-binding adapter molecule 1 (Iba-1) staining, did not differ between groups, whereas plaque associated microglia was more abundant in J20 CNR2⁻/⁻ mice. Total tau was significantly suppressed in J20 CNR2⁻/⁻ mice relative to J20 CNR2⁺/⁺ mice. The results confirm the constitutive role of the CB₂ receptor system both in reducing amyloid plaque pathology in AD and also support tehpotential of cannabinoid therapies targeting CB₂ to reduce Aβ; however, the results suggest that interventions may have a divergent effect on tau pathology.

Microarray and pathway analysis reveal distinct mechanisms underlying cannabinoid-mediated modulation of LPS-induced activation of BV-2 microglial cells

Cannabinoids are known to exert immunosuppressive activities. However, the mechanisms which contribute to these effects are unknown. Using lipopolysaccharide (LPS) to activate BV-2 microglial cells, we examined how Δ⁹-tetrahydrocannabinol (THC), the major psychoactive component of marijuana, and cannabidiol (CBD) the non-psychoactive component, modulate the inflammatory response. Microarray analysis of genome-wide mRNA levels was performed using Illumina platform and the resulting expression patterns analyzed using the Ingenuity Pathway Analysis to identify functional subsets of genes, and the Ingenuity System Database to denote the gene networks regulated by CBD and THC. From the 5338 transcripts that were differentially expressed across treatments, 400 transcripts were found to be upregulated by LPS, 502 by CBD+LPS and 424 by THC+LPS, while 145 were downregulated by LPS, 297 by CBD+LPS and 149 by THC+LPS, by 2-fold or more (p≤0.005). Results clearly link the effects of CBD and THC to inflammatory signaling pathways and identify new cannabinoid targets in the MAPK pathway (Dusp1, Dusp8, Dusp2), cell cycle related (Cdkn2b, Gadd45a) as well as JAK/STAT regulatory molecules (Socs3, Cish, Stat1). The impact of CBD on LPS-stimulated gene expression was greater than that of THC. We attribute this difference to the fact that CBD highly upregulated several genes encoding negative regulators of both NFκB and AP-1 transcriptional activities, such as Trib3 and Dusp1 known to be modulated through Nrf2 activation. The CBD-specific expression profile reflected changes associated with oxidative stress and glutathione depletion via Trib3 and expression of ATF4 target genes. Furthermore, the CBD affected genes were shown to be controlled by nuclear factors usually involved in regulation of stress response and inflammation, mainly via Nrf2/Hmox1 axis and the Nrf2/ATF4-Trib3 pathway. These observations indicate that CBD, and less so THC, induce a cellular stress response and that this response underlies their high immunosuppressant activities.

Inhibition of apolipoprotein A-I gene expression by obesity-associated endocannabinoids

Obesity is associated with increased serum endocannabinoid (EC) levels and decreased high-density lipoprotein cholesterol (HDLc). Apolipoprotein A-I (apo A-I), the primary protein component of HDL is expressed primarily in the liver and small intestine. To determine whether ECs regulate apo A-I gene expression directly, the effect of the obesity-associated ECs anandamide and 2-arachidonylglycerol on apo A-I gene expression was examined in the hepatocyte cell line HepG2 and the intestinal cell line Caco-2. Apo A-I protein secretion was suppressed nearly 50% by anandamide and 2-arachidonoylglycerol in a dose-dependent manner in both cell lines. Anandamide treatment suppressed both apo A-I mRNA and apo A-I gene promoter activity in both cell lines. Studies using apo A-I promoter deletion constructs indicated that repression of apo A-I promoter activity by anandamide requires a previously identified nuclear receptor binding site designated as site A. Furthermore, anandamide-treatment inhibited protein-DNA complex formation with the site A probe. Exogenous over expression of cannabinoid receptor 1 (CBR1) in HepG2 cells suppressed apo A-I promoter activity, while in Caco-2 cells, exogenous expression of both CBR1 and CBR2 could repress apo A-I promoter activity. The suppressive effect of anandamide on apo A-I promoter activity in Hep G2 cells could be inhibited by CBR1 antagonist AM251 but not by AM630, a selective and potent CBR2 inhibitor. These results indicate that ECs directly suppress apo A-I gene expression in both hepatocytes and intestinal cells, contributing to the decrease in serum HDLc in obese individuals.

The cannabinoid receptors agonist WIN55212-2 inhibits macrophageal differentiation and alters expression and phosphorylation of cell cycle control proteins

In this study we investigated if and how cannabinoid receptor stimulation regulates macrophageal differentiation, which is one of the key steps in the immune effector reaction. For that reason, we used a well established differentiation model system of human U937 myelocytic leukemia cells that differentiate along the monocyte/macrophage lineage upon stimulation with the phorbol ester PMA. Constant cannabinoid receptor (CB) stimulation was performed using WIN55212-2, a potent synthetic CB agonist. We found that WIN55212-2 inhibited CB1/2-receptor-dependent PMA-induced differentiation of human myelocytic U937 cells into the macrophageal phenotype, which was associated with impaired vimentin, ICAM-1 and CD11b expression. In the presence of WIN55212-2, cdc2 protein and mRNA expression was progressively enhanced and Tyr-15-phosporylation of cdc2 was reduced in differentiating U937 cells. Additionally, p21^Waf1/Cip1 expression was up-regulated. PMA-induced apoptosis was not enhanced by WIN55212-2 and differentiation-associated c-jun expression was not altered. In conclusion, we suppose that WIN55212-2-induced signals interferes with cell-cycle-arrest-signaling in differentiating myelocytic cells and thus inhibits macrophageal differentiation. Thus, it is possible that the cannabinoid system is able to influence one of the key steps in the immune effector function, the monocytic-macrophageal differentiation by alteration of cell cycle control proteins cdc2 and p21, and is therefore representing a promising option for therapeutic intervention in exacerbated immune reactions.

Marijuana use and motor vehicle crashes

Since 1996, 16 states and the District of Columbia in the United States have enacted legislation to decriminalize marijuana for medical use. Although marijuana is the most commonly detected nonalcohol drug in drivers, its role in crash causation remains unsettled. To assess the association between marijuana use and crash risk, the authors performed a meta-analysis of 9 epidemiologic studies published in English in the past 2 decades identified through a systematic search of bibliographic databases. Estimated odds ratios relating marijuana use to crash risk reported in these studies ranged from 0.85 to 7.16. Pooled analysis based on the random-effects model yielded a summary odds ratio of 2.66 (95% confidence interval: 2.07, 3.41). Analysis of individual studies indicated that the heightened risk of crash involvement associated with marijuana use persisted after adjustment for confounding variables and that the risk of crash involvement increased in a dose-response fashion with the concentration of 11-nor-9-carboxy-delta-9-tetrahydrocannabinol detected in the urine and the frequency of self-reported marijuana use. The results of this meta-analysis suggest that marijuana use by drivers is associated with a significantly increased risk of being involved in motor vehicle crashes.

Perinatal exposure to Δ9-tetrahydrocannabinol triggers profound defects in T cell differentiation and function in fetal and postnatal stages of life, including decreased responsiveness to HIV antigens

Marijuana abuse is very prominent among pregnant women. Although marijuana cannabinoids have been shown to exert immunosuppression in adults, virtually nothing is known about the effects of marijuana use during pregnancy on the developing immune system of the fetus and during postnatal life. We noted that murine fetal thymus expressed high levels of the cannabinoid receptors CB1 and CB2. Moreover, perinatal exposure to Δ(9)-tetrahydrocannabinol (THC) had a profound effect on the fetus as evidenced by a decrease in thymic cellularity on gestational days 16, 17, and 18 and postgestational day 1 and marked alterations in T cell subpopulations. These outcomes were reversed by CB1/CB2 antagonists, suggesting that THC-mediated these effects through cannabinoid receptors. Thymic atrophy induced in the fetus correlated with caspase-dependent apoptosis in thymocytes. Thymic atrophy was the result of direct action of THC and not based on maternal factors inasmuch as THC was able to induce T cell apoptosis in vitro in fetal thymic organ cultures. It is noteworthy that perinatal exposure to THC also had a profound effect on the immune response during postnatal life. Peripheral T cells from such mice showed decreased proliferative response to T cell mitogen as well as both T cell and antibody response to HIV-1 p17/p24/gp120 antigens. Together, our data demonstrate for the first time that perinatal exposure to THC triggers profound T cell dysfunction, thereby suggesting that the offspring of marijuana abusers who have been exposed to THC in utero may be at a higher risk of exhibiting immune dysfunction and contracting infectious diseases including HIV.

Methylenedioxymethamphetamine ('Ecstasy')-induced immunosuppression: a cause for concern?

Methylenedioxymethamphetamine (MDMA; 'Ecstasy') is a ring-substituted amphetamine and a popular drug of abuse. In addition to ability to induce euphoria, MDMA abuse is associated with a range of acute and long-term hazardous effects. This paper is focused on once such adverse effect: its ability to negatively impact on functioning of the immune system. Research demonstrates that MDMA has immunosuppressive properties, with both innate and adaptive arms of the immune system being affected. The ability of MDMA to suppress innate immunity is indicated by impaired neutrophil phagocytosis and reduced production of dendritic cell/macrophage-derived pro-inflammatory cytokines including tumour necrosis factor-alpha, interleukin (IL)-1beta, IL-12 and IL-15. MDMA also suppresses innate IFN-gamma production, and considering the role of IFN-gamma in priming antigen-presenting cells, it is not surprising that MDMA reduces MHC class II expression on dendritic cells and macrophages, and inhibits co-stimulatory molecule expression. Paradoxically, studies demonstrate that MDMA elicits pro-inflammatory actions in the CNS by activating microglia, the resident innate immune cells in the brain. In terms of adaptive immunity, MDMA reduces circulating lymphocyte numbers, particularly CD4(+) T-cells; suppresses T-cell proliferation; and skews cytokine production in a Th(2) direction. For the most part, the immunosuppressive effects of MDMA cannot be attributed to a direct action of the drug on immune cells, but rather due to the release of endogenous immunomodulatory substances. In this regard, peripheral beta-adrenoceptors and cholinergic receptors have been shown to mediate some immunosuppressive effects of MDMA. Finally, we discuss emerging evidence indicating that MDMA-induced immunosuppression can translate into significant health risks for abusers.

Cannabinoids and Viral Infections

Exogenous cannabinoids or receptor antagonists may influence many cellular and systemic host responses. The anti-inflammatory activity of cannabinoids may compromise host inflammatory responses to acute viral infections, but may be beneficial in persistent infections. In neurons, where innate antiviral/pro-resolution responses include the activation of NOS-1, inhibition of Ca²⁺ activity by cannabinoids, increased viral replication and disease. This review examines the effect(s) of cannabinoids and their antagonists in viral infections.

Cannabinoid conditioned reward and aversion: behavioral and neural processes

The discovery that delta-9-tetrahydrocannabinol (Δ(9)-THC) is the primary psychoactive ingredient in marijuana prompted research that helped elucidate the endogenous cannabinoid system of the brain. Δ(9)-THC and other cannabinoid ligands with agonist action (CP 55,940, HU210, and WIN 55,212-2) increase firing of dopamine neurons and increase synaptic dopamine in brain regions associated with reward and drug addiction. Such changes in cellular processes have prompted investigators to examine the conditioned rewarding effects of the cannabinoid ligands using the place conditioning task with rats and mice. As reviewed here, these cannabinoid ligands can condition place preferences (evidence for rewarding effects) and place aversions (evidence for aversive qualities). Notably, the procedural details used in these place conditioning studies have varied across laboratories. Such variation includes differences in apparatus type, existence of procedural biases, dose, number of conditioning trials, injection-to-placement intervals, and pre-training drug exposure. Some differences in outcome across studies can be explained by these procedural variables. For example, low doses of Δ(9)-THC appear to have conditioned rewarding effects, whereas higher doses have aversive effects that either mask these rewarding effects or condition a place aversion. Throughout this review we highlight key areas that need further research.

Immunoactive effects of cannabinoids: considerations for the therapeutic use of cannabinoid receptor agonists and antagonists

The active constituents of Cannabis sativa have been used for centuries as recreational drugs and medicinal agents. Today, marijuana is the most prevalent drug of abuse in the United States and, conversely, therapeutic use of marijuana constituents are gaining mainstream clinical and political acceptance. Given the documented contributions of endocannabinoid signaling to a range of physiological systems, including cognitive function, and the control of eating behaviors, it is unsurprising that cannabinoid receptor agonists and antagonists are showing significant clinical potential. In addition to the neuroactive effects of cannabinoids, an emerging body of data suggests that both endogenous and exogenous cannabinoids are potently immunoactive. The central premise of this review article is that the immunological effects of cannabinoids should be considered in the context of each prescribing decision. We present evidence that the immunological effects of cannabinoid receptor agonists and antagonists are highly relevant to the spectrum of disorders for which cannabinoid therapeutics are currently offered.

Antibody response to hepatitis B vaccine in substance use disorder patients

The objectives of this study were to assess the prevalence of prognostic factors previously known to be associated with poor antibody response to hepatitis B vaccination in a sample of veterans presenting for substance use disorders treatment at a Veterans Health Administration (VA) Medical Center, assess vaccination response, and identify markers for poor response in this population. Results indicated that most participants had multiple prognostic factors previously known to be associated with poor antibody response including male gender, age over 40, smoking, and obesity. The rate of seroconversion in this sample was 51.9%. This is substantially lower than seen in healthy adults. Alcohol dependence was the only significant independent negative predictor of seroconversion in this sample. Substance use disorders treatment providers who are considering adding hepatitis B vaccination services to their clinics should be aware that the antibody response to the hepatitis B vaccination is inconsistent and that patients with particular demographic characteristics may be at heightened risk of poor antibody response.

Cannabinoids and the immune system: an overview

Cannabinoids can influence the immune network. Data on the impact of exogenous cannabinoid ligands on immune function serve not only to understand how the endocannabinoid system modulates immune phenomena associated with infection or inflammation, but also to identify therapeutic targets for immune diseases. Cannabinoids can modulate immune reactions in the periphery but also in the brain, influence T cell subset balance and cytokine expression and play a role in the balance between neuroinflammation and neurodegeneration. Immune cells can synthesize endocannabinoids and also be influenced by cannabinoid analogues. Cannabinoid receptors show different expression on immune cells depending on activation status and stimuli. The complexity of relation between cannabinoid ligands of various classes and cannabinoid receptors brought the need to refine the simple conceptual frame of agonist-antagonists and offered potential implications for understanding interactions in pathological conditions. The immune influence of cannabinoid ligands is not fully elucidated. However, aspects of their immunomodulatory effects provide the basis for a context-dependent targeted therapeutic approach, thus leading to the possibility for the use of cannabinoids in the treatment of inflammatory disease.

Cannabinoid system in the skin - a possible target for future therapies in dermatology

Cannabinoids and their derivatives are group of more than 60 biologically active chemical agents, which have been used in natural medicine for centuries. The major agent of exogenous cannabinoids is Delta(9)-tetrahydrocannabinol (Delta(9)-THC), natural psychoactive ingredient of marijuana. However, psychoactive properties of these substances limited their use as approved medicines. Recent discoveries of endogenous cannabinoids (e.g. arachidonoylethanolamide, 2-arachidonoylglycerol or palmithyloethanolamide) and their receptors initiated discussion on the role of cannabinoid system in physiological conditions as well as in various diseases. Based on the current knowledge, it could be stated that cannabinoids are important mediators in the skin, however their role have not been well elucidated yet. In our review, we summarized the current knowledge about the significant role of the cannabinoid system in the cutaneous physiology and pathology, pointing out possible future therapeutic targets.

Cannabinoids and experimental models of multiple sclerosis

The inflammatory response is a hallmark in the development of autoimmune-mediated neurodegenerative diseases of the central nervous system (CNS). Research on these pathological phenomena is being extensively undertaken and experimental autoimmune encephalomyelitis (EAE) serves as a valuable animal model. Studies from this model have generated interesting insights into biological effects of cannabinoids and may, at least to a certain extent, reflect the cannabinoid-mediated protective mechanisms also in human diseases with similar characteristics, such as multiple sclerosis (MS). Cannabinoids are involved in regulation of the immune system. These effects comprise modulation of inflammatory reaction through components of the innate and adaptive immune responses. Cannabinoids also confer neuroprotection and assist neuroregeneration, thus maintaining a balance within the delicate CNS microenvironment and restoring function following pathological condition, commonly driven by neuroinflammation. Continued studies of cannabinoid actions in EAE pathogenesis should be beneficial for the better understanding of the mechanisms governing such a vast array of physiological effects and in development of new therapeutic strategies for the treatment of human neuroinflammatory and neurodegenerative diseases.

Emerging role of the cannabinoid receptor CB2 in immune regulation: therapeutic prospects for neuroinflammation

There is now a large body of data indicating that the cannabinoid receptor type 2 (CB2) is linked to a variety of immune events. This functional relevance appears to be most salient in the course of inflammation, a process during which there is an increased number of receptors that are available for activation. Studies aimed at elucidating signal transduction events resulting from CB2 interaction with its native ligands, and of the role of exogenous cannabinoids in modulating this process, are providing novel insights into the role of CB2 in maintaining a homeostatic immune balance within the host. Furthermore, these studies suggest that the CB2 may serve as a selective molecular target for therapeutic manipulation of untoward immune responses, including those associated with a variety of neuropathies that exhibit a hyperinflammatory component.

Targeting the endocannabinoid system in Alzheimer's disease

The endocannabinoid system is rapidly emerging as a potential drug target for a variety of immune-mediated central nervous system diseases. There is a growing body of evidence suggesting that endocannabinoid interventions may have particular relevance to Alzheimer's disease. Here we present a review of endocannabinoid physiology, the evidence that underscores its utility as a potential target for intervention in Alzheimer's disease, and suggest future pathways of research.

Reduced serum concentrations of nerve growth factor, but not brain-derived neurotrophic factor, in chronic cannabis abusers

Chronic cannabis use produces effects within the central nervous system (CNS) which include deficits in learning and attention tasks and decreased brain volume. Neurotrophins, in particular nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), are proteins that serve as survival factors for CNS neurons. Deficits in the production and utilization of these proteins can lead to CNS dysfunctions including those associated with cannabis abuse. In this study we measured by enzyme-linked immunosorbent assay (ELISA) the NGF and BDNF serum levels in two groups of subjects: cannabis-dependent patients and healthy subjects. We found that NGF serum levels were significantly reduced in cannabis abusers as compared to healthy subjects. These findings indicate that NGF may have a role in the central action of cannabis and potentially in the neurotoxicity induced by this drug. These data also suggest that chronic cannabis consumption may be a risk factor for developing psychosis among drug users.

The cannabinoid delta-9-tetrahydrocannabinol mediates inhibition of macrophage chemotaxis to RANTES/CCL5: linkage to the CB2 receptor

The chemotactic response of murine peritoneal macrophages to RANTES/CCL5 was inhibited significantly following pretreatment with delta-9-tetrahydrocannabinol (THC), the major psychoactive component in marijuana. Significant inhibition of this chemokine directed migratory response was obtained also when the full cannabinoid agonist CP55940 was used. The CB2 receptor-selective ligand O-2137 exerted a robust inhibition of chemotaxis while the CB1 receptor-selective ligand ACEA had a minimal effect. The THC-mediated inhibition was reversed by the CB2 receptor-specific antagonist SR144528 but not by the CB1 receptor-specific antagonist SR141716A. In addition, THC treatment had a minimal effect on the chemotactic response of peritoneal macrophages from CB2 knockout mice. Collectively, these results suggest that cannabinoids act through the CB2 receptor to transdeactivate migratory responsiveness to RANTES/CCL5. Furthermore, the results suggest that the CB2 receptor may be a constituent element of a network of G protein-coupled receptor signal transductional systems, inclusive of chemokine receptors, that act coordinately to modulate macrophage migration.

Distinct risk factor profiles for human papillomavirus type 16-positive and human papillomavirus type 16-negative head and neck cancers

BACKGROUND

High-risk types of human papillomavirus (HPV), including HPV-16, cause a subgroup of head and neck squamous cell carcinomas (HNSCCs). We examined whether the risk factors for HPV-16-positive HNSCCs are similar to those for HPV-16-negative HNSCCs in a hospital-based case-control study.

METHODS

Case subjects (n = 240) diagnosed with HNSCC at the Johns Hopkins Hospital from 2000 through 2006 were stratified by tumor HPV-16 status as determined by in situ hybridization. Two control subjects (n = 322) without cancer were individually matched by age and sex to each HPV-16-positive and HPV-16-negative case subject. Data on risk behaviors were obtained by use of audio computer-assisted self-interview technology. Multivariable conditional logistic regression models were used to estimate the odds ratios (ORs) for HPV-16-positive HNSCC and HPV-16-negative HNSCC associated with risk factors. All statistical tests were two-sided.

RESULTS

HPV-16 was detected in 92 of 240 case subjects. HPV-16-positive HNSCC was independently associated with several measures of sexual behavior and exposure to marijuana but not with cumulative measures of tobacco smoking, alcohol drinking, or poor oral hygiene. Associations increased in strength with increasing number of oral sex partners (P(trend) = .01) and with increasing intensity (joints per month, P(trend) = .007), duration (in years, P(trend) = .01), and cumulative joint-years (P(trend) = .003) of marijuana use. By contrast, HPV-16-negative HNSCC was associated with measures of tobacco smoking, alcohol drinking, and poor oral hygiene but not with any measure of sexual behavior or marijuana use. Associations increased in strength with increasing intensity (cigarettes per day), duration, and cumulative pack-years of tobacco smoking (for all, P(trend) < .001), increasing years of heavy alcohol drinking (> or = 15 years of 14 drinks per week; P(trend) = .03), and increasing number of lost teeth (P(trend) = .001). Compared with subjects who neither smoked tobacco nor drank alcohol, those with heavy use of tobacco (> or = 20 pack-years) and alcohol had an increased risk of HPV-16-negative HNSCC (OR = 4.8, 95% confidence interval [CI] = 1.8 to 12) but not of HPV-16-positive HNSCC (OR = 0.67, 95% CI = 0.29 to 1.9).

CONCLUSIONS

HPV-16-positive HNSCCs and HPV-16-negative HNSCCs have different risk factor profiles, indicating that they should be considered to be distinct cancers.

Marijuana as therapy for people living with HIV/AIDS: social and health aspects

Therapeutic use of marijuana has emerged as an important issue for people living with cancer, HIV/AIDS and multiple sclerosis. This paper examines therapeutic use of marijuana in the Positive Health cohort study, a longitudinal cohort study of men and women living with HIV/AIDS in NSW and Victoria, Australia. Factors that distinguish therapeutic use of marijuana from recreational use were assessed by comparisons on a range of social and health-related variables. The results show that among 408 participants, 59.8% reported some use of marijuana in the past six months. Of those participants (n=244), 55.7% reported recreational use only of marijuana and 44.3% report mixed use of marijuana for therapeutic and recreational purposes. Multivariate logistic regression analysis showed that participants who used marijuana for therapeutic purposes were significantly more likely than recreational-only users to have used other complementary or alternative therapies, experienced HIV/AIDS-related illness or other illnesses in the past 12 months, had higher CD4/T-cell counts, had lower incomes, be younger in age and less likely to have had a casual partner in the six months prior to interview. These results show that a substantial proportion of people living with HIV/AIDS (PLWHA) use marijuana for therapeutic purposes, despite considerable legal barriers, suggesting marijuana represents another option in their health management. Rather than solely using marijuana in response to illness, the experience of illness may influence a person's understanding of their marijuana use, so that they come to understand it as therapeutic. Further research might consider possible interactions between cannabinoids and antiretroviral treatments, potential use of oral THC and the difficulties faced by clinicians and PLWHA in discussing marijuana in the current legal context.

Anti-inflammatory property of the cannabinoid receptor-2-selective agonist JWH-133 in a rodent model of autoimmune uveoretinitis

Previous studies have shown that cannabinoids have anti-inflammatory and immune-modulating effects, but the precise mechanisms of action remain to be elucidated. In this study, we investigated the effect of JWH 133, a selective agonist for cannabinoid receptor 2, the main receptor expressed on immune cells, in a model of autoimmune disease, experimental autoimmune uveoretinitis (EAU). JWH 133 suppressed EAU in a dose-dependent manner (0.015-15 mg/kg), and the suppressive effect could be achieved in the disease-induction stage and the effector stage. Leukocytes from mice, which had been treated with JWH 133, had diminished responses to retinal peptide and mitogen Con A stimulation in vitro. In vivo JWH 133 treatment also abrogated leukocyte cytokine/chemokine production. Further in vitro studies indicated that JWH 133 down-regulated the TLR4 via Myd88 signal transduction, which may be responsible for its moderate, suppressive effect on antigen presentation. In vivo JWH 133 treatment (1 mg/kg) also suppressed leukocyte trafficking (rolling and infiltration) in inflamed retina as a result of an effect on reducing adhesion molecules CD162 (P-selectin glycoprotein ligand 1) and CD11a (LFA-1) expression on T cells. In conclusion, the cannabinoid agonist JWH 133 has a high in vivo, anti-inflammatory property and may exert its effect via inhibiting the activation and function of autoreactive T cells and preventing leukocyte trafficking into the inflamed tissue.

Temporal variation in CB2R levels following T lymphocyte activation: Evidence that cannabinoids modulate CXCL12-induced chemotaxis

Cannabinoids have long been proposed to affect the immune system, especially as one of the cannabinoid receptors, the cannabinoid receptor-2 (CB(2)R) has been found almost exclusively on immune cells. Here, using human in vitro activated peripheral blood-derived T lymphocytes we investigated the long-term changes in cannabinoid receptor protein expression following cellular activation and the effects of cannabinoids on migration. We report that resting T lymphocytes do not detectably express either the cannabinoid receptor-1 (CB(1)R) or CB(2)R at the protein level. However, CB(2)R protein expression is upregulated in a biphasic manner in T lymphocytes following activation by superantigen. The cannabinoids 2-AG and JWH-133 were found to elicit activation of downstream biochemical effectors (as assessed by the phosphorylation of the ERK1/2 MAP kinases). Neither 2-AG nor JWH-133 induced chemotaxis in day 5 activated T lymphocytes, when receptor expression was at its highest. Interestingly, both 2-AG and JWH-133 inhibited CXCL12-induced chemotaxis, suggesting a modulatory role for cannabinoids in activated T lymphocytes.

Therapeutic Potential of Cannabinoid-Based Drugs

Cannabinoid-based drugs modeled on cannabinoids originally isolated from marijuana are now known to significantly impact the functioning of the endocannabinoid system of mammals. This system operates not only in the brain but also in organs and tissues in the periphery including the immune system. Natural and synthetic cannabinoids are tricyclic terpenes, whereas the endogenous physiological ligands are eicosanoids. Several receptors for these compounds have been extensively described, CB1 and CB2, and are G protein-coupled receptors; however, cannabinoid-based drugs are also demonstrated to function independently of these receptors. Cannabinoids regulate many physiological functions and their impact on immunity is generally antiinflammatory as powerful modulators of the cytokine cascade. This anti-inflammatory potency has led to the testing of these drugs in chronic inflammatory laboratory paradigms and even in some human diseases. Psychoactive and nonpsychoactive cannabinoid-based drugs such as Delta9-tetrahydrocannabinol, cannabidiol, HU-211, and ajulemic acid have been tested and found moderately effective in clinical trials of multiple sclerosis, traumatic brain injury, arthritis, and neuropathic pain. Furthermore, although clinical trials are not yet reported, preclinical data with cannabinoid-based drugs suggest efficacy in other inflammatory diseases such as inflammatory bowel disease, Alzheimer's disease, atherosclerosis, and osteoporosis.

Neuropharmacology of the endocannabinoid signaling system-molecular mechanisms, biological actions and synaptic plasticity

The endocannabinoid signaling system is composed of the cannabinoid receptors; their endogenous ligands, the endocannabinoids; the enzymes that produce and inactivate the endocannabinoids; and the endocannabinoid transporters. The endocannabinoids are a new family of lipidic signal mediators, which includes amides, esters, and ethers of long-chain polyunsaturated fatty acids. Endocannabinoids signal through the same cell surface receptors that are targeted by Delta(9)-tetrahydrocannabinol (Delta(9)THC), the active principles of cannabis sativa preparations like hashish and marijuana. The biosynthetic pathways for the synthesis and release of endocannabinoids are still rather uncertain. Unlike neurotransmitter molecules that are typically held in vesicles before synaptic release, endocannabinoids are synthesized on demand within the plasma membrane. Once released, they travel in a retrograde direction and transiently suppress presynaptic neurotransmitter release through activation of cannabinoid receptors. The endocannabinoid signaling system is being found to be involved in an increasing number of pathological conditions. In the brain, endocannabinoid signaling is mostly inhibitory and suggests a role for cannabinoids as therapeutic agents in central nervous system (CNS) disease. Their ability to modulate synaptic efficacy has a wide range of functional consequences and provides unique therapeutic possibilities. The present review is focused on new information regarding the endocannabinoid signaling system in the brain. First, the structure, anatomical distribution, and signal transduction mechanisms of cannabinoid receptors are described. Second, the synthetic pathways of endocannabinoids are discussed, along with the putative mechanisms of their release, uptake, and degradation. Finally, the role of the endocannabinoid signaling system in the CNS and its potential as a therapeutic target in various CNS disease conditions, including alcoholism, are discussed.