Evaluation of Oxidant/Antioxidant Status and Cytokine Levels in Patients with Cannabis Use Disorder

Levels of Synovial Fluid Inflammatory Biomarkers on Day of Arthroscopic Partial Meniscectomy Predict Long-Term Outcomes and Conversion to TKA: A 10-Year Mean Follow-up Study

BACKGROUND

The purpose of the present study was to evaluate the relationships of the concentrations of pro- and anti-inflammatory biomarkers in the knee synovial fluid at the time of arthroscopic partial meniscectomy (APM) to long-term patient-reported outcomes (PROs) and conversion to total knee arthroplasty (TKA).

METHODS

A database of patients who underwent APM for isolated meniscal injury was analyzed. Synovial fluid had been aspirated from the operatively treated knee prior to the surgical incision, and concentrations of pro- and anti-inflammatory biomarkers (RANTES, IL-6, MCP-1, MIP-1β, VEGF, TIMP-1, TIMP-2, IL-1RA, MMP-3, and bFGF) were quantified. Prior to surgery and again at the time of final follow-up, patients were asked to complete a survey that included a visual analog scale (VAS) for pain and Lysholm, Tegner, and Knee injury and Osteoarthritis Outcome Score-Physical Function Short Form (KOOS-PS) questionnaires. Clustering analysis of the 10 biomarkers of interest was carried out with the k-means algorithm.

RESULTS

Of the 82 patients who met the inclusion criteria for the study, 59 had not undergone subsequent ipsilateral TKA or APM, and 43 (73%) of the 59 completed PRO questionnaires at long-term follow-up. The mean follow-up time was 10.6 ± 1.3 years (range, 8.7 to 12.4 years). Higher concentrations of individual pro-inflammatory biomarkers including MCP-1 (β = 13.672, p = 0.017) and MIP-1β (β = -0.385, p = 0.012) were associated with worse VAS pain and Tegner scores, respectively. K-means clustering analysis separated the cohort of 82 patients into 2 groups, one with exclusively higher levels of pro-inflammatory biomarkers than the second group. The "pro-inflammatory phenotype" cohort had a significantly higher VAS pain score (p = 0.024) and significantly lower Lysholm (p = 0.022), KOOS-PS (p = 0.047), and Tegner (p = 0.009) scores at the time of final follow-up compared with the "anti-inflammatory phenotype" cohort. The rate of conversion to TKA was higher in the pro-inflammatory cohort (29.4% versus 12.2%, p = 0.064). Logistic regression analysis demonstrated that the pro-inflammatory phenotype was significantly correlated with conversion to TKA (odds ratio = 7.220, 95% confidence interval = 1.028 to 50.720, p = 0.047).

CONCLUSIONS

The concentrations of synovial fluid biomarkers on the day of APM can be used to cluster patients into pro- and anti-inflammatory cohorts that are predictive of PROs and conversion to TKA at long-term follow-up.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effect of Cannabis Usage on Thyroid Eye Disease

PURPOSE

The purpose of this study is to investigate the association between cannabis usage and thyroid eye disease (TED) in patients with autoimmune hyperthyroidism. While the association between cigarette smoking and TED is well established, the effect of cannabis on TED is unclear.

METHODS

This cohort study examined data from TriNetX, an electronic health record platform, for patients with autoimmune hyperthyroidism between December 1, 2003, and December 1, 2023. Primary outcomes were TED presentation (exophthalmos, eyelid retraction, eyelid edema, orbital edema, strabismus, and optic neuropathy) and treatment (teprotumumab, methylprednisolone, tarsorrhaphy, and orbital decompression) in cannabis users, nicotine users, and control patients. Propensity matching was performed to control for characteristics such as age, sex, race, prior thyroidectomy, and/or radio ablation. Relative risk between cohorts was calculated for each outcome in 6-month, 1-year, and 2-year intervals following diagnosis of autoimmune hyperthyroidism.

RESULTS

Of 36,186 patients with autoimmune hyperthyroidism, 783 were cannabis users, 17,310 were nicotine users, and 18,093 were control patients without cannabis or nicotine usage. Compared with control patients, cannabis users were more likely to be younger, male, and Black/African American and have anxiety or depression. After propensity matching, cannabis users were 1.9 times more likely to develop exophthalmos (p = 0.03) and 1.6 times more likely to develop any TED presentation (p = 0.049) in the 1-year interval although these differences did not remain statistically significant in the 2-year interval.

CONCLUSIONS

Cannabis users had a significantly increased risk for TED outcomes in the 1-year interval. Further research is needed to inform TED management.

Cardioprotective effect of CB1 receptor antagonist AM251 against β receptor-stimulated myocardial infarction via modulation of NF-kB signaling pathway in diabetic mice

We substantiated the effect of AM251, a cannabinoid receptor-1 (CB1R) antagonist, against β-receptor stimulated myocardial infarction (MI) in streptozotocin (STZ)-induced diabetic mice via modulation- of the NF-kB signaling pathway. The different parameters were assessed such as ECG, hemodynamic, cardiac injury markers, oxidative stress parameters, pro-inflammatory cytokines, and histopathological abnormalities. Mice were fed a high-fat diet for 30 days. On day 7, to trigger diabetes, 150 mg/kg of STZ was injected intraperitoneally. On day 10, to determine whether diabetes developed, the blood level of glucose was monitored. From days 11-30, diabetic mice were injected with either CB1R agonist oleamide or antagonist AM251 or both, with concurrent administrations of β-agonist isoproterenol on days 28 and 29 to induce MI. In comparison to normal, the myocardial infarcted diabetic animals demonstrated alterations in ECG, hemodynamic profiles, and diminished enzymatic activities (CK-MB, LDH, SOD, GSH, catalase), with concurrently increased MDA levels, which indicated increased oxidative stress in the myocardium. Additionally, higher concentrations of cytokines that signal myocardial inflammation, such as IL-1β, IL-6, and TNF-α, were also noted. Furthermore, elevated myonecrosis, edema, and cell infiltration which is confirmed by histopathology of heart tissue. Treatment with AM251 significantly ameliorated myocardial redox status, reduced cytokines, and repaired enzymatic activities leading to subsequent recovery in cardiac function. AM251 effectively suppressed myonecrosis and edema. This study also showed that AM251 protects against myocardial inflammation and oxidative stress triggered by isoproterenol by blocking NF-kB signalling pathway. However, upregulation of the CB1R through oleamide showed significant cardiac toxicity. Conversely, the concurrent administration of oleamide and AM251 failed to induce cardiotoxic effects in isoproterenol-induced MI in diabetic mice which indicates downregulation of the CB1R might be associated with the cardioprotective effect.

Evaluation of Complete Blood Cell Count Parameters and Their Role in Inflammation in Patients with Methamphetamine and Synthetic Cannabis Use Disorder

Background

The aim of this study was to compare the complete blood cell count parameters of patients with methamphetamine and synthetic cannabis use disorder (MCUD), a condition that has recently exhibited a gradual increase in prevalence, with those of healthy subjects.

Methods

In total, 76 patients diagnosed with MCUD and 78 healthy controls were included in the study. Venous blood samples were collected from all participants at presentation for laboratory examination.

Results

The rate of mono- and poly-substance users in the patient group was 14.5% and 85.5%, respectively. The average duration of methamphetamine (METH) use in the patient group is 3.0 ± 1.9 years. White blood cell (P < .001), PLT (P = .005), monocyte count (P < .001), basophil count (P < .001), neutrophil count (P < .001), lymphocyte count (P < .001) basophil/lymphocyte ratio (BLR) (P = .04), SII (P = .006), and SIRI (P = .001) values were significantly higher. In contrast Hgb (P = .043), Hct (P = .002), monocyte percentage (P = .004), and RBC (P = .021) values were significantly lower in the MCUD group compared to the control group. There was a significant positive correlation between neutrophil/lymphocyte ratio and platelet/lymphocyte ratio (r = .552 P < .001) and between systemic immune inflammatory index (SII) and systemic inflammation response index (SIRI) (r = 0.580 P < .001).

Conclusion

Methamphetamine and cannabis may affect the levels of inflammatory markers and SII and SIRI values through various mechanisms. To the best of our knowledge, this is the first study in the relevant literature, which investigated SII and SIRI values in patients with MCUD, therefore, the results can contribute to the future development of immune system-related markers in this field.

Influence of supplementation with iron and probiotic bacteria Lactobacillus plantarum and Lactobacillus curvatus on selected parameters of inflammatory state in rats on a high-fat iron-deficient diet

BACKGROUND

A high-fat (HF) diet, diet iron deficiency and iron supplementation may affect inflammatory parameters. Probiotics influence both iron metabolism and inflammation. We compared the inflammatory state in rats on a HF iron-deficient diet receiving oral iron, Lactobacillus plantarum and Lactobacillus curvatus in different combinations.

METHODS

This was a two-stage experiment. In groups C (n = 8) and HF (n = 8), rats ate a control or HF diet, respectively, for 16 weeks. In the group HFDEF (n = 48), rats ate a HF iron-deficient diet for 8 weeks (first stage) and were subsequently divided into 6 groups (n = 8 each) receiving the following for a further 8 weeks (second stage): HFDEF - a HF iron-deficient diet; HFDEFFe - a HF iron-deficient diet with iron; HFDEFLp and HFDEFLc - a HF iron-deficient diet with L. plantarum or L. curvatus, respectively; and HFDEFFeLp and HFDEFFeLc - a HF iron-deficient diet with iron and L. plantarum or L. curvatus, respectively. Body composition analysis and blood sampling was performed. Markers of iron status and levels of total antioxidant status (TAS), C-reactive protein (CRP), tumour necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) were measured in the blood.

RESULTS

TAS was higher in the HFDEF group (756.57 ± 489.53 ng mL-1) versus the HFDEFLc group (187.04 ± 47.84 ng mL-1; P = 0.022). No more differences were found between groups, or in TAS, CRP, TNF-α and IL-6 concentrations. Also, no differences were found between groups for alanine and aspartate aminotransferases, glucose, total cholesterol, low- and high-density lipoproteins and triglycerides. TAS level was positively correlated with ferritin concentration, IL-6 with TAS and TNF-α with hepcidin level.

CONCLUSIONS

Supplementation with L. plantarum, L. curvatus and iron in combinations exerts no influence on inflammatory status, lipid profile, hepatic function and serum fasting glucose in rats on a HF iron-deficient diet. © 2024 Society of Chemical Industry.

Neuroactive Steroids, Toll-like Receptors, and Neuroimmune Regulation: Insights into Their Impact on Neuropsychiatric Disorders

Pregnane neuroactive steroids, notably allopregnanolone and pregnenolone, exhibit efficacy in mitigating inflammatory signals triggered by toll-like receptor (TLR) activation, thus attenuating the production of inflammatory factors. Clinical studies highlight their therapeutic potential, particularly in conditions like postpartum depression (PPD), where the FDA-approved compound brexanolone, an intravenous formulation of allopregnanolone, effectively suppresses TLR-mediated inflammatory pathways, predicting symptom improvement. Additionally, pregnane neurosteroids exhibit trophic and anti-inflammatory properties, stimulating the production of vital trophic proteins and anti-inflammatory factors. Androstane neuroactive steroids, including estrogens and androgens, along with dehydroepiandrosterone (DHEA), display diverse effects on TLR expression and activation. Notably, androstenediol (ADIOL), an androstane neurosteroid, emerges as a potent anti-inflammatory agent, promising for therapeutic interventions. The dysregulation of immune responses via TLR signaling alongside reduced levels of endogenous neurosteroids significantly contributes to symptom severity across various neuropsychiatric disorders. Neuroactive steroids, such as allopregnanolone, demonstrate efficacy in alleviating symptoms of various neuropsychiatric disorders and modulating neuroimmune responses, offering potential intervention avenues. This review emphasizes the significant therapeutic potential of neuroactive steroids in modulating TLR signaling pathways, particularly in addressing inflammatory processes associated with neuropsychiatric disorders. It advances our understanding of the complex interplay between neuroactive steroids and immune responses, paving the way for personalized treatment strategies tailored to individual needs and providing insights for future research aimed at unraveling the intricacies of neuropsychiatric disorders.

Immune and glial cell alterations in the rat brain after repeated exposure to the synthetic cannabinoid JWH-018

The use of synthetic cannabinoid receptor agonists (SCRAs) poses major psychiatric risks. We previously showed that repeated exposure to the prototypical SCRA JWH-018 induces alterations in dopamine (DA) transmission, abnormalities in the emotional state, and glial cell activation in the mesocorticolimbic DA circuits of rats. Despite growing evidence suggesting the relationship between substance use disorders (SUD) and neuroinflammation, little is known about the impact of SCRAs on the neuroimmune system. Here, we investigated whether repeated JWH-018 exposure altered neuroimmune signaling, which could be linked with previously reported central effects. Adult male Sprague-Dawley (SD) rats were exposed to JWH-018 (0.25 mg/kg, i.p.) for fourteen consecutive days, and the expression of cytokines, chemokines, and growth factors was measured seven days after treatment discontinuation in the striatum, cortex, and hippocampus. Moreover, microglial (ionized calcium-binding adaptor molecule 1, IBA-1) and astrocyte (glial fibrillary acidic protein, GFAP) activation markers were evaluated in the caudate-putamen (CPu). Repeated JWH-018 exposure induces a perturbation of neuroimmune signaling specifically in the striatum, as shown by increased levels of cytokines [interleukins (IL) -2, -4, -12p70, -13, interferon (IFN) γ], chemokines [macrophage inflammatory protein (MIP) -1α, -3α], and growth factors [macrophage colony-stimulating factor (M-CSF), vascular endothelial growth factor (VEGF)], together with increased IBA-1 and GFAP expression in the CPu. JWH-018 exposure induces persistant brain region-specific immune alterations up to seven days after drug discontinuation, which may contribute to the behavioral and neurochemical dysregulations in striatal areas that play a role in the reward-related processes that are frequently impaired in SUD.

THC improves behavioural schizophrenia-like deficits that CBD fails to overcome: a comprehensive multilevel approach using the Poly I:C maternal immune activation

Prenatal infections and cannabis use during adolescence are well-recognized risk factors for schizophrenia. As inflammation and oxidative stress (OS) contribute to this disorder, anti-inflammatory drugs have been proposed as potential therapies. This study aimed to evaluate the association between delta-9-tetrahydrocannabinol (THC) and schizophrenia-like abnormalities in a maternal immune activation (MIA) model. Additionally, we assessed the preventive effect of cannabidiol (CBD), a non-psychotropic/anti-inflammatory cannabinoid. THC and/or CBD were administered to Saline- and MIA-offspring during periadolescence. At adulthood, THC-exposed MIA-offspring showed significant improvements in sensorimotor gating deficits. Structural and metabolic brain changes were evaluated by magnetic resonance imaging, revealing cortical shrinkage in Saline- and enlargement in MIA-offspring after THC-exposure. Additionally, MIA-offspring displayed enlarged ventricles and decreased hippocampus, which were partially reverted by both cannabinoids. CBD prevented THC-induced reduction in the corpus callosum, despite affecting white matter structure. Post-mortem studies revealed detrimental effects of THC, including increased inflammation and oxidative stress. CBD partially reverted these pro-inflammatory alterations and modulated THC's effects on the endocannabinoid system. In conclusion, contrary to expectations, THC exhibited greater behavioural and morphometric benefits, despite promoting a pro-inflammatory state that CBD partially reverted. Further research is needed to elucidate the underlying mechanisms involved in the observed benefits of THC.

Health status outcome among cannabis addicts after treatment of addiction

The abuse of Cannabis is a widespread issue in the Asir region. It has a lot of legal and occupational repercussions. The purpose of this study was to evaluate the health status of cannabis addicts at admission and after treatment using body mass index, glycemic status, liver function, renal function, and oxidative stress. A cross-sectional study was conducted with 120 participants. The study was conducted at Al Amal Hospital for Mental Health in Asir region of Saudi Arabia, with 100 hospitalized patients receiving addiction treatment and 20 healthy volunteers. The participants were divided into two groups: group I, the control group, and group II, the cannabis addicts. The socio-demographic data were gathered. The level of cannabis in the urine and the CWAS [Cannabis Withdrawal Assessment Scale] were determined. In addition, the Body Mass Index [BMI], vital signs [temperature, heart rate, systolic blood pressure, diastolic blood pressure, and respiratory rate], serum levels of albumin, total bilirubin, direct bilirubin, AST, ALT, and ALP, urea, creatinine, Thiobarbituric acid-reactive substances [TBARS], superoxide dismutase [SOD], reduced glutathione [GSH], and catalase [CAT] were analyzed on the first day of admission and after treatment. According to the results, there was no significant change in the body mass index. The vital signs in the cannabis user group were significantly lower than the corresponding admission values. Regarding renal function tests such as urea and creatinine, we found that after treatment, the mean urea and creatinine values in the cannabis user group did not differ significantly from the corresponding admission values. However, after treatment, the mean values of fasting blood glucose levels in the cannabis user group were significantly lower than at admission. Also, the mean values of liver function tests such as albumin, total bilirubin, direct bilirubin, AST, ALT, and ALP in the cannabis user group were significantly lower than the corresponding admission values after treatment. In assessing the antioxidant system, we found that the mean values of TBARS, SOD, GSH, and CAT in the cannabis user group did not differ significantly from the corresponding admission values after treatment. The current findings have revealed that cannabis addiction harms the various body systems and has significant implications for the addict's state of health. The values of oxidative stress biomarkers did not change in this study, but other measured parameters improved after treatment.

Perturbation of 3D nuclear architecture, epigenomic dysregulation and aging, and cannabinoid synaptopathy reconfigures conceptualization of cannabinoid pathophysiology: part 1-aging and epigenomics

Much recent attention has been directed toward the spatial organization of the cell nucleus and the manner in which three-dimensional topologically associated domains and transcription factories are epigenetically coordinated to precisely bring enhancers into close proximity with promoters to control gene expression. Twenty lines of evidence robustly implicate cannabinoid exposure with accelerated organismal and cellular aging. Aging has recently been shown to be caused by increased DNA breaks. These breaks rearrange and maldistribute the epigenomic machinery to weaken and reverse cellular differentiation, cause genome-wide DNA demethylation, reduce gene transcription, and lead to the inhibition of developmental pathways, which contribute to the progressive loss of function and chronic immune stimulation that characterize cellular aging. Both cell lineage-defining superenhancers and the superanchors that control them are weakened. Cannabis exposure phenocopies the elements of this process and reproduces DNA and chromatin breakages, reduces the DNA, RNA protein and histone synthesis, interferes with the epigenomic machinery controlling both DNA and histone modifications, induces general DNA hypomethylation, and epigenomically disrupts both the critical boundary elements and the cohesin motors that create chromatin loops. This pattern of widespread interference with developmental programs and relative cellular dedifferentiation (which is pro-oncogenic) is reinforced by cannabinoid impairment of intermediate metabolism (which locks in the stem cell-like hyper-replicative state) and cannabinoid immune stimulation (which perpetuates and increases aging and senescence programs, DNA damage, DNA hypomethylation, genomic instability, and oncogenesis), which together account for the diverse pattern of teratologic and carcinogenic outcomes reported in recent large epidemiologic studies in Europe, the USA, and elsewhere. It also accounts for the prominent aging phenotype observed clinically in long-term cannabis use disorder and the 20 characteristics of aging that it manifests. Increasing daily cannabis use, increasing use in pregnancy, and exponential dose-response effects heighten the epidemiologic and clinical urgency of these findings. Together, these findings indicate that cannabinoid genotoxicity and epigenotoxicity are prominent features of cannabis dependence and strongly indicate coordinated multiomics investigations of cannabinoid genome-epigenome-transcriptome-metabolome, chromatin conformation, and 3D nuclear architecture. Considering the well-established exponential dose-response relationships, the diversity of cannabinoids, and the multigenerational nature of the implications, great caution is warranted in community cannabinoid penetration.

Oxidative Stress and Inflammatory Biomarkers in People with Methamphetamine Use Disorder

Objective

This study aimed to investigate the blood serum levels of biomarkers specifying oxidative stress status and systemic inflammation between people using methamphetamine (METH) and the control group (CG). Serum thiol/disulfide balance and ischemia-modified albumin levels were studied to determine oxidative stress, and serum interleukin-6 (IL-6) levels and complete blood count (CBC) were to assess inflammation.

Methods

Fifty patients with METH use disorder (MUD) and 36 CG participants were included in the study. Two tubes of venous blood samples were taken to measure oxidative stress, serum thiol/disulfide balance, ischemia-modified albumin, and IL-6 levels between groups. The correlation of parameters measuring oxidative stress and inflammation between groups with sociodemographic data was investigated.

Results

In this study, serum total thiol, free thiol levels, disulfide/native thiol percentage ratios, and serum ischemia- modified albumin levels of the patients were statistically significantly higher than the healthy controls. No difference was observed between the groups in serum disulfide levels and serum IL-6 levels. Considering the regression analysis, only the duration of substance use was a statistically significant factor in explaining serum IL-6 levels. The parameters showing inflammation in the CBC were significantly higher in the patients than in the CG.

Conclusion

CBC can be used to evaluate systemic inflammation in patients with MUD. Parameters measuring thiol/disulfide homeostasis and ischemia-modified albumin can be, also, used to assess oxidative stress.

Inflammation, Dopaminergic Brain and Bilirubin

Dopamine is a well-known neurotransmitter due to its involvement in Parkinson's disease (PD). Dopamine is not only involved in PD but also controls multiple mental and physical activities, such as the pleasure of food, friends and loved ones, music, art, mood, cognition, motivation, fear, affective disorders, addiction, attention deficit disorder, depression, and schizophrenia. Dopaminergic neurons (DOPAn) are susceptible to stressors, and inflammation is a recognized risk for neuronal malfunctioning and cell death in major neurodegenerative diseases. Less is known for non-neurodegenerative conditions. Among the endogenous defenses, bilirubin, a heme metabolite, has been shown to possess important anti-inflammatory activity and, most importantly, to prevent DOPAn demise in an ex vivo model of PD by acting on the tumor necrosis factor-alpha (TNFα). This review summarizes the evidence linking DOPAn, inflammation (when possible, specifically TNFα), and bilirubin as an anti-inflammatory in order to understand what is known, the gaps that need filling, and the hypotheses of anti-inflammatory strategies to preserve dopamine homeostasis with bilirubin included.

Thiol disulfide homeostasis in psychiatric disorders: A comprehensive review

Thiol-disulfide couple maintains an intracellular redox status. Dynamic thiol-disulfide homeostasis acts crucial parts in metabolic processes involving signal mechanisms, inflammation, antioxidant defense. Thiol-disulfide homeostasis have been implicated in numerous diseases. In this comprehensive review we identified the studies that examined the thiol-disulfide homeostasis in psychiatric disorders. Most cases demonstrated alterations in thiol-disulfide homeostasis and in most of them the thiol-disulfide balance tended to change direction to the disulfide side, that is, to the oxidative side. Currently, the fact that N-acetylcysteine, a thiol-containing compound, is of great interest as a new treatment approach in psychiatric disorders and the role of glutathione, the most abundant thiol, in the brain highlights the importance of evaluating the thiol-disulfide balance in psychiatric disorders.

Deletion of Cryab increases the vulnerability of mice to the addiction-like effects of the cannabinoid JWH-018 via upregulation of striatal NF-κB expression

Synthetic cannabinoids have exhibited unpredictable abuse liabilities, especially self-administration (SA) responses in normal rodent models, despite seemingly inducing addiction-like effects in humans. Thus, an efficient pre-clinical model must be developed to determine cannabinoid abuse potential in animals and describe the mechanism that may mediate cannabinoid sensitivity. The Cryab knockout (KO) mice were recently discovered to be potentially sensitive to the addictive effects of psychoactive drugs. Herein, we examined the responses of Cryab KO mice to JWH-018 using SA, conditioned place preference, and electroencephalography. Additionally, the effects of repeated JWH-018 exposure on endocannabinoid- and dopamine-related genes in various addiction-associated brain regions were examined, along with protein expressions involving neuroinflammation and synaptic plasticity. Cryab KO mice exhibited greater cannabinoid-induced SA responses and place preference, along with divergent gamma wave alterations, compared to wild-type (WT) mice, implying their higher sensitivity to cannabinoids. Endocannabinoid- or dopamine-related mRNA expressions and accumbal dopamine concentrations after repeated JWH-018 exposure were not significantly different between the WT and Cryab KO mice. Further analyses revealed that repeated JWH-018 administration led to possibly greater neuroinflammation in Cryab KO mice, which may arise from upregulated NF-κB, accompanied by higher expressions of synaptic plasticity markers, which might have contributed to the development of cannabinoid addiction-related behavior in Cryab KO mice. These findings signify that increased neuroinflammation via NF-κB may mediate the enhanced addiction-like responses of Cryab KO mice to cannabinoids. Altogether, Cryab KO mice may be a potential model for cannabinoid abuse susceptibility.

The Inflammatory Signals Associated with Psychosis: Impact of Comorbid Drug Abuse

Psychosis and substance use disorders are two diagnostic categories whose association has been studied for decades. In addition, both psychosis spectrum disorders and drug abuse have recently been linked to multiple pro-inflammatory changes in the central nervous system. We have carried out a narrative review of the literature through a holistic approach. We used PubMed as our search engine. We included in the review all relevant studies looking at pro-inflammatory changes in psychotic disorders and substance use disorders. We found that there are multiple studies that relate various pro-inflammatory lipids and proteins with psychosis and substance use disorders, with an overlap between the two. The main findings involve inflammatory mediators such as cytokines, chemokines, endocannabinoids, eicosanoids, lysophospholipds and/or bacterial products. Many of these findings are present in different phases of psychosis and in substance use disorders such as cannabis, cocaine, methamphetamines, alcohol and nicotine. Psychosis and substance use disorders may have a common origin in an abnormal neurodevelopment caused, among other factors, by a neuroinflammatory process. A possible convergent pathway is that which interrelates the transcriptional factors NFκB and PPARγ. This may have future clinical implications.

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.

Stress- and drug-induced neuroimmune signaling as a therapeutic target for comorbid anxiety and substance use disorders

Stress and substance use disorders remain two of the most highly prevalent psychiatric conditions and are often comorbid. While individually these conditions have a debilitating impact on the patient and a high cost to society, the symptomology and treatment outcomes are further exacerbated when they occur together. As such, there are few effective treatment options for these patients, and recent investigation has sought to determine the neural processes underlying the co-occurrence of these disorders to identify novel treatment targets. One such mechanism that has been linked to stress- and addiction-related conditions is neuroimmune signaling. Increases in inflammatory factors across the brain have been heavily implicated in the etiology of these disorders, and this review seeks to determine the nature of this relationship. According to the "dual-hit" hypothesis, also referred to as neuroimmune priming, prior exposure to either stress or drugs of abuse can sensitize the neuroimmune system to be hyperresponsive when exposed to these insults in the future. This review completes an examination of the literature surrounding stress-induced increases in inflammation across clinical and preclinical studies along with a summarization of the evidence regarding drug-induced alterations in inflammatory factors. These changes in neuroimmune profiles are also discussed within the context of their impact on the neural circuitry responsible for stress responsiveness and addictive behaviors. Further, this review explores the connection between neuroimmune signaling and susceptibility to these conditions and highlights the anti-inflammatory pharmacotherapies that may be used for the treatment of stress and substance use disorders.

Adolescent self-administration of the synthetic cannabinoid receptor agonist JWH-018 induces neurobiological and behavioral alterations in adult male mice

RATIONALE

The use of synthetic cannabinoid receptor agonists (SCRAs) is growing among adolescents, posing major medical and psychiatric risks. JWH-018 represents the reference compound of SCRA-containing products.

OBJECTIVES

This study was performed to evaluate the enduring consequences of adolescent voluntary consumption of JWH-018.

METHODS

The reinforcing properties of JWH-018 were characterized in male CD1 adolescent mice by intravenous self-administration (IVSA). Afterwards, behavioral, neurochemical, and molecular evaluations were performed at adulthood.

RESULTS

Adolescent mice acquired operant behavior (lever pressing, Fixed Ratio 1-3; 7.5 µg/kg/inf); this behavior was specifically directed at obtaining JWH-018 since it increased under Progressive Ratio schedule of reinforcement, and was absent in vehicle mice. JWH-018 IVSA was reduced by pretreatment of the CB1-antagonist/inverse agonist AM251. Adolescent exposure to JWH-018 by IVSA increased, at adulthood, both nestlet shredding and marble burying phenotypes, suggesting long-lasting repetitive/compulsive-like behavioral effects. JWH-018 did not affect risk proclivity in the wire-beam bridge task. In adult brains, there was an increase of ionized calcium binding adaptor molecule 1 (IBA-1) positive cells in the caudate-putamen (CPu) and nucleus accumbens (NAc), along with a decrease of glial fibrillary acidic protein (GFAP) immunoreactivity in the CPu. These glial alterations in adult brains were coupled with an increase of the chemokine RANTES and a decrease of the cytokines IL2 and IL13 in the cortex, and an increase of the chemokine MPC1 in the striatum.

CONCLUSIONS

This study suggests for the first time that male mice self-administer the prototypical SCRA JWH-018 during adolescence. The adolescent voluntary consumption of JWH-018 leads to long-lasting behavioral and neurochemical aberrations along with glia-mediated inflammatory responses in adult brains.

Drugs and Bugs: The Gut-Brain Axis and Substance Use Disorders

Substance use disorders (SUDs) represent a significant public health crisis. Worldwide, 5.4% of the global disease burden is attributed to SUDs and alcohol use, and many more use psychoactive substances recreationally. Often associated with comorbidities, SUDs result in changes to both brain function and physiological responses. Mounting evidence calls for a precision approach for the treatment and diagnosis of SUDs, and the gut microbiome is emerging as a contributor to such disorders. Over the last few centuries, modern lifestyles, diets, and medical care have altered the health of the microbes that live in and on our bodies; as we develop, our diets and lifestyle dictate which microbes flourish and which microbes vanish. An increase in antibiotic treatments, with many antibiotic interventions occurring early in life during the microbiome's normal development, transforms developing microbial communities. Links have been made between the microbiome and SUDs, and the microbiome and conditions that are often comorbid with SUDs such as anxiety, depression, pain, and stress. A better understanding of the mechanisms influencing behavioral changes and drug use is critical in developing novel treatments for SUDSs. Targeting the microbiome as a therapeutic and diagnostic tool is a promising avenue of exploration. This review will provide an overview of the role of the gut-brain axis in a wide range of SUDs, discuss host and microbe pathways that mediate changes in the brain's response to drugs, and the microbes and related metabolites that impact behavior and health within the gut-brain axis.

Cannabinoid receptor 1 antagonist genistein attenuates marijuana-induced vascular inflammation

Epidemiological studies reveal that marijuana increases the risk of cardiovascular disease (CVD); however, little is known about the mechanism. Δ⁹-tetrahydrocannabinol (Δ⁹-THC), the psychoactive component of marijuana, binds to cannabinoid receptor 1 (CB1/CNR1) in the vasculature and is implicated in CVD. A UK Biobank analysis found that cannabis was an risk factor for CVD. We found that marijuana smoking activated inflammatory cytokines implicated in CVD. In silico virtual screening identified genistein, a soybean isoflavone, as a putative CB1 antagonist. Human-induced pluripotent stem cell-derived endothelial cells were used to model Δ⁹-THC-induced inflammation and oxidative stress via NF-κB signaling. Knockdown of the CB1 receptor with siRNA, CRISPR interference, and genistein attenuated the effects of Δ⁹-THC. In mice, genistein blocked Δ⁹-THC-induced endothelial dysfunction in wire myograph, reduced atherosclerotic plaque, and had minimal penetration of the central nervous system. Genistein is a CB1 antagonist that attenuates Δ⁹-THC-induced atherosclerosis.

Standardized Cannabis Smoke Extract Induces Inflammation in Human Lung Fibroblasts

Cannabis (marijuana) is the most commonly used illicit product in the world and is the second most smoked plant after tobacco. There has been a rapid increase in the number of countries legalizing cannabis for both recreational and medicinal purposes. Smoking cannabis in the form of a joint is the most common mode of cannabis consumption. Combustion of cannabis smoke generates many of the same chemicals as tobacco smoke. Although the impact of tobacco smoke on respiratory health is well-known, the consequence of cannabis smoke on the respiratory system and, in particular, the inflammatory response is unclear. Besides the combustion products present in cannabis smoke, cannabis also contains cannabinoids including Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD). These compounds are hydrophobic and not present in aqueous solutions. In order to understand the impact of cannabis smoke on pathological mechanisms associated with adverse respiratory outcomes, the development of in vitro surrogates of cannabis smoke exposure is needed. Therefore, we developed a standardized protocol for the generation of cannabis smoke extract (CaSE) to investigate its effect on cellular mechanisms in vitro. First, we determined the concentration of Δ9-THC, one of the major cannabinoids, by ELISA and found that addition of methanol to the cell culture media during generation of the aqueous smoke extract significantly increased the amount of Δ9-THC. We also observed by LC-MS/MS that CaSE preparation with methanol contains CBD. Using a functional assay in cells for CB1 receptors, the major target of cannabinoids, we found that this CaSE contains Δ9-THC which activates CB1 receptors. Finally, this standardized preparation of CaSE induces an inflammatory response in human lung fibroblasts. This study provides an optimized protocol for aqueous CaSE preparation containing biologically active cannabinoids that can be used for in vitro experimentation of cannabis smoke and its potential impact on various indices of pulmonary health.

Serum lipid analysis and isotopic enrichment is suggestive of greater lipogenesis in young long-term cannabis users: A secondary analysis of a case-control study

Cannabis is now legal in many countries and while numerous studies have reported on its impact on cognition and appetite regulation, none have examined fatty acid metabolism in young cannabis users. We conducted an exploratory analysis to evaluate cannabis impact on fatty acid metabolism in cannabis users (n = 21) and non-cannabis users (n = 16). Serum levels of some saturated and monounsaturated fatty acids, including palmitic, palmitoleic, and oleic acids were higher in cannabis users compared to nonusers. As palmitic acid can be derived from diet or lipogenesis from sugars, we evaluated lipogenesis using a de novo lipogenesis index (palmitate/linoleic acid) and carbon-specific isotope analysis, which allows for the determination of fatty acid ¹³ C signature. The significantly higher de novo lipogenesis index in the cannabis users group along with a more enriched ¹³ C signature of palmitic acid suggested an increase in lipogenesis. In addition, while serum glucose concentration did not differ between groups, pyruvate and lactate were lower in the cannabis user group, with pyruvate negatively correlating with palmitic acid. Furthermore, the endocannabinoid 2-arachidonoylglycerol was elevated in cannabis users and could contribute to lipogenesis by activating the cannabinoid receptor 1. Because palmitic acid has been suggested to increase inflammation, we measured peripheral cytokines and observed no changes in inflammatory cytokines. Finally, an anti-inflammatory metabolite of palmitic acid, palmitoylethanolamide was elevated in cannabis users. Our results suggest that lipogenic activity is increased in cannabis users; however, future studies, including prospective studies that control dietary intake are required.

Polygenic networks in peripheral leukocytes indicate patterns associated with HIV infection and context-dependent effects of cannabis use

In spite of suppressive antiretroviral therapies (ART), Human Immunodeficiency Virus (HIV)-infected subjects still experience the consequences of viral persistence and chronic inflammation. In the brain, where most HIV-1 targets are of innate immune origin, neurological and cognitive impairments are detectable and enhanced by highly prevalent substance use disorders. Cannabis is one of the most prevalent substances among HIV+ ​subjects, compared to non-infected populations, either prescribed for improving various symptoms or used recreationally, as well as a component of polysubstance use. The mechanisms by which addictive substances and HIV interact are multifactorial and poorly understood. Importantly, the HIV brain target cells, macrophages and microglia, express receptors to neurotransmitters elevated by such drugs, and express receptors to cannabinoids, particularly CB2R. We have tested a panel of 784 transcripts associated with neurological disorders, digitally multiplexed and detectable in peripheral blood cells from a small cohort (n ​= ​102) of HIV-positive (HIV+) and HIV-negative (HIV-) specimens, stratified based on criteria of lifetime (LT) dependence of cannabis (CAN+) or not (CAN-). Demographic homogeneity and low incidence of co-morbidities helped increase power and allowed the identification of key differences consistent with HIV infection, cannabis exposure, or their interactions. A small percentage of these subjects used cannabis as well as other drugs. The data was analyzed using robust systems and visualization strategies to detect orchestrated patterns in gene networks connected based on molecular interfaces with higher power than in single genes. We found that the effects of cannabis differed drastically between HIV- and HIV+ ​groups, particularly in gene networks playing a role in inflammation, neurodegeneration, apoptosis and leukocyte adhesion and transmigration. At the level of individual genes, we identified detrimental effects that were associated with polysubstance use as a covariate, particularly methamphetamine. Transcription factor usage predictions suggest that the effects of cannabis are associated with transcriptional co-regulation at the gene promoters by multiple factors that vary by context. Overall, we have found that the effects of cannabis may be context-dependent, with potential benefits in the context of HIV reflected by improvements in cognition, but in the absence of the polysubstance use component.

The relation of optical coherence tomography findings with oxidative stress parameters in patients with bipolar disorder and unaffected first-degree relatives

BACKGROUND

We aimed to evaluate the optical coherence tomography(OCT) findings and oxidative stress parameters in patients with bipolar disorder(BD) and their unaffected first-degree relatives(FDRs) and to explore OCT findings and oxidative stress parameters as potential endophenotype candidates.

METHODS

Fifty patients with BD, 40 FDRs of BD, and 50 healthy controls(HCs) were included. OCT was performed to measure peripapillary retinal nerve fiber layer(RNFL), ganglion cell layer(GCL), inner plexiform layer(IPL), central macular, and minimum foveal thicknesses(CMT and MFT), choroidal thickness(ChT). 4-hydroxy-2-nonenal(HNE), total thiol(TT), native thiol(NT), total oxidant status(TOS), total antioxidant status(TAS), disulfide(DIS) and oxidative stress index(OSI) were measured from serum samples.

RESULTS

TOS was higher patients with BD and FDRs than HCs (p < .001 and p = .012, respectively). OSI, DIS, HNE levels were higher patients with BD and FDRs than HCs (p < .001). TAS, TT, NT levels were lower patients and FDRs than HCs (p < .001). MFT of patients was thinner than HCs (p = .001). CMT of patients was thinner than HCs (p = .006); the same trend was observed in FDRs but did not reach the statistical significance level (p = .07). The groups did not differ on RNFL and choroidal thickness or GCL and IPL volume.

LIMITATIONS

Evaluation of only a few retinal layers.

CONCLUSIONS

TOS, TAS, OSI, TT, NT, DIS, HNE can be useful endophenotype biomarkers in BD. Among the OCT findings, CMT was determined as the closest parameter to being an endophenotype biomarker. Our study corroborates that oxidative stress parameters are more effective than OCT findings in endophenotype studies.

Inflammatory Biomarkers in Addictive Disorders

Substance use disorders are a group of diseases that are associated with social, professional, and family impairment and that represent a high socio-economic impact on the health systems of countries around the world. These disorders present a very complex diagnosis and treatment regimen due to the lack of suitable biomarkers supporting the correct diagnosis and classification and the difficulty of selecting effective therapies. Over the last few years, several studies have pointed out that these addictive disorders are associated with systemic and central nervous system inflammation, which could play a relevant role in the onset and progression of these diseases. Therefore, identifying different immune system components as biomarkers of such addictive disorders could be a crucial step to promote appropriate diagnosis and treatment. Thus, this work aims to provide an overview of the immune system alterations that may be biomarkers of various addictive disorders.

Pro-Inflammatory Cytokines: Potential Links between the Endocannabinoid System and the Kynurenine Pathway in Depression

Substance use/abuse is one of the main causes of depressive symptoms. Cannabis and synthetic cannabinoids in particular gained significant popularity in the past years. There is an increasing amount of clinical data associating such compounds with the inflammatory component of depression, indicated by the up-regulation of pro-inflammatory cytokines. Pro-inflammatory cytokines are also well-known to regulate the enzymes of the kynurenine pathway (KP), which is responsible for metabolizing tryptophan, a precursor in serotonin synthesis. Enhanced pro-inflammatory cytokine levels may over-activate the KP, leading to tryptophan depletion and reduced serotonin levels, which can subsequently precipitate depressive symptoms. Therefore, such mechanism might represent a possible link between the endocannabinoid system (ECS) and the KP in depression, via the inflammatory and dysregulated serotonergic component of the disorder. This review will summarize the data regarding those natural and synthetic cannabinoids that increase pro-inflammatory cytokines. Furthermore, the data on such cytokines associated with KP activation will be further reviewed accordingly. The interaction of the ECS and the KP has been postulated and demonstrated in some studies previously. This review will further contribute to this yet less explored connection and propose the KP to be the missing link between cannabinoid-induced inflammation and depressive symptoms.

Association between chronic psychoactive substances use and systemic inflammation: A systematic review and meta-analysis

This systematic review and meta-analysis assess the change in inflammation biomarkers level among chronic psychoactive substance users. To meet the required inclusion criteria, all studies had to describe human participants with an age ≥18y., experiencing chronic psychostimulant (nicotine, amphetamine, cocaine), sedative (benzodiazepine, opioids) and/or cannabinoid use. The comparison group was defined as healthy participants. Studies where included if they reported at least one of the pro/inflammatory biomarkers. Study bias was examined by Funnel plots and heterogeneity by computing the I² statistics. Only 21 eligible studies were selected based on 26,216 study participants. A small and significant effect size of 0.18 mg/l (95 % CI:0.10-0.27) was detected in favour of chronic smokers (z = 4.33;P < 0.0001). There was evidence of publication bias for studies measuring IL-6 and IL-10 association with cocaine and IL-6 in association with cannabis. In summary, except for chronic tobacco users, there was no evidence of association between other chronic substances abuse and inflammatory levels. More studies are needed to inform policy and decision makers about the utility of anti-inflammatory based targeted intervention programmes.

The concomitant use of cannabis and cocaine coexists with increased LPS levels and systemic inflammation in male drug users

Illicit drug use can cause a variety of effects including alterations in the immune system. The aim of this study was to investigate the effects of illicit drugs on circulating lipopolysaccharide (LPS), systemic inflammation and oxidative stress markers in drug users. We evaluated the levels of soluble CD14 (sCD14), LPS, inflammatory (TNF-α and IL-6) and regulatory (IL-10) cytokines, as well as C-reactive protein (CRP), lipid peroxidation (TBARS) and total thiols in the peripheral blood of 81 men included in groups of cannabis (n = 21), cocaine (n = 12), cannabis-plus-cocaine users (n = 27), and non-drug users (n = 21). The use of cannabis plus cocaine leads to higher systemic levels of LPS, CRP, IL-6 and higher IL-6/IL-10 ratio, characterizing a proinflammatory profile. In contrast, a regulatory profile as viewed by lower systemic TNF-α and IL-6 levels and lower TNF-α/IL-10 ratio were observed in cannabis users compared to the control group. Moreover, cocaine users presented a lower content of non-enzymatic antioxidant thiol compared to control group, cannabis group and cannabis plus cocaine group. In conclusion, our results indicate that the use of cannabis contributes to an anti-inflammatory/or regulatory profile while the concomitant cannabis plus cocaine consumption coexists with increased circulating amounts of LPS and proinflammatory status.

Cannabinoid use in psychotic patients impacts inflammatory levels and their association with psychosis severity

Inflammatory abnormalities are well-documented in individuals with chronic psychotic disorders. Particular attention has focused on interleukin-6 (IL-6) and its correlation with psychotic symptom severity. Cannabis use is associated with an increased risk of psychosis and also has immunomodulating properties. It has been hypothesized that inflammatory disturbances are a common underlying pathology between cannabis use and psychosis. We measured inflammatory markers in individuals admitted to a psychiatric unit with acute psychosis who had toxicology positive for natural and/or synthetic cannabinoids (n = 59) compared to patients with negative cannabinoid toxicology (n = 60). Psychosis severity was assessed using the Positive and Negative Syndrome Scale (PANSS). While PANSS scores were similar between groups, cannabinoid-positive participants were more likely to receive pro re nata (PRN or as-needed) medications for agitation in the psychiatric emergency room, particularly synthetic cannabinoid-positive participants. In unadjusted models, cannabinoid-positive participants had lower interferon-γ (IFN-γ) levels (p = 0.046), but this finding was not significant after adjusting for covariates and multiple comparisons. Among cannabinoid-positive participants, IL-6 levels negatively correlated with PANSS total score (p = 0.040), as well as positive (p = 0.035) and negative (p = 0.024) subscales. Results suggest inflammatory alterations among psychotic individuals with comorbid cannabinoid use.

Accumulation rate of advanced glycation end products in recent onset psychosis: A longitudinal study

Schizophrenia is associated with excessive oxidative stress. Production of advanced glycation end products (AGEs) in the skin is strongly associated with oxidative stress. Increased skin AGE-levels have been demonstrated at cross-sectional level in recent onset psychosis and chronic schizophrenia, indicating increased cardiovascular risk. We aimed to investigate factors underlying AGE-accumulation and accumulation rate of AGEs in recent onset psychosis. From December 2016 through May 2017, 66 patients and 160 (highly educated) healthy controls from a previous case-control study of AGE-levels were assessed for a follow-up measurement 12-24 months after baseline. Possible determinants of AGE-accumulation were analyzed. AGE-accumulation rates in patients and controls were compared adjusted for relevant confounders. In healthy controls, a significant association of AGE-accumulation with ethnicity and tobacco exposure was found. An indication of a markedly higher AGE-accumulation rate was found in patients suffering from recent onset psychosis compared to healthy controls, independent of ethnicity and tobacco smoking, but not independent of cannabis use (more prevalent in patients than controls), although results were not significant.

Potential of Glial Cell Modulators in the Management of Substance Use Disorders

The pervasive and devastating nature of substance use disorders underlies the need for the continued development of novel pharmacotherapies. We now know that glia play a much greater role in neuronal processes than once believed.  The various types of glial cells (e.g., astrocytes, microglial, oligodendrocytes) participate in numerous functions that are crucial to healthy central nervous system function. Drugs of abuse have been shown to interact with glia in ways that directly contribute to the pharmacodynamic effects responsible for their abuse potential. Through their effect upon glia, drugs of abuse also alter brain function resulting in behavioral changes associated with substance use disorders. Therefore, drug-induced changes in glia and inflammation within the central nervous system (neuroinflammation) have been investigated to treat various aspects of drug abuse and dependence. This article presents a brief overview of the effects of each of the major classes of addictive drugs on glia. Next, the paper reviews the pre-clinical and clinical studies assessing the effects that glial modulators have on abuse-related behavioral effects, such as pleasure, withdrawal, and motivation. There is a strong body of pre-clinical literature demonstrating the general effectiveness of several glia-modulating drugs in models of reward and relapse. Clinical studies have also yielded promising results, though not as robust. There is still much to disentangle regarding the integration between addictive drugs and glial cells. Improved understanding of the relationship between glia and the pathophysiology of drug abuse should allow for more precise exploration in the development and testing of glial-directed treatments for substance use disorders.

Investigation of DNA damage, oxidative stress, and inflammation in synthetic cannabinoid users

BACKGROUND

The widespread use of synthetic cannabinoids (SCs) among youth has become an important public health problem. Several life-threatening side effects of SC have been reported, including cardiovascular, gastrointestinal, neurological, renal, metabolic, ophthalmologic, and pulmonary effects, besides skin toxicity and hepatotoxicity.

METHODS

Given that high levels of SC can lead to oxidative stress, DNA damage, and inflammation, it has been aimed in this study to investigate the effects of SC in aspects of primary DNA damage, plasma total oxidant status (TOS)/total antioxidant status (TAS), thiol-disulfide homeostasis, myeloperoxidase (MPO) level, and cytokine levels (interleukin 1 beta (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-α)) of 40 SC users (SCUs) in Turkey.

RESULTS

Mean plasma TOS levels were significantly higher in the SCUs group than in the healthy group (HG). Similarly, mononuclear leukocyte DNA damage, plasma TOS, MPO activity, disulfide, oxidative stress index levels, IL-1β, IL-6, and TNF-α levels were significantly higher in the SCU group than in the HG, whereas plasma TAS, total, and native thiol levels were significantly lower in the SCU group than in the HG.

CONCLUSION

It is concluded that SC can cause increase in oxidative stress and in inflammatory processes in addition to its potential for DNA damage. Additional studies with larger sample sizes and longer durations should be held to understand more specific outcomes of SC use.

In Vivo Imaging of Translocator Protein in Long-term Cannabis Users

IMPORTANCE

Cannabis is the most commonly used illicit drug in the world. Cannabinoids have been shown to modulate immune responses; however, the association of cannabis with neuroimmune function has never been investigated in vivo in the human brain.

OBJECTIVE

To investigate neuroimmune activation or 18-kDa translocator protein (TSPO) levels in long-term cannabis users, and to evaluate the association of brain TSPO levels with behavioral measures and inflammatory blood biomarkers.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study based in Toronto, Ontario, recruited individuals from January 1, 2015, to October 30, 2018. Participants included long-term cannabis users (n = 24) and non-cannabis-using controls (n = 27). Cannabis users were included if they had a positive urine drug screen for only cannabis and if they used cannabis at least 4 times per week for the past 12 months and/or met the criteria for cannabis use disorder. All participants underwent a positron emission tomography scan with [18F]FEPPA, or fluorine F 18-labeled N-(2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide.

MAIN OUTCOMES AND MEASURES

Total distribution volume was quantified across regions of interest. Stress and anxiety as well as peripheral measures of inflammatory cytokines and C-reactive protein levels were also measured.

RESULTS

In total, 24 long-term cannabis users (mean [SD] age, 23.1 [3.8] years; 15 men [63%]) and 27 non-cannabis-using controls (mean [SD] age, 23.6 [4.2] years; 18 women [67%]) were included and completed all study procedures. Compared with the controls, cannabis users had higher [18F]FEPPA total distribution volume (main group effect: F1,48 = 6.5 [P = .01]; ROI effect: F1,200 = 28.4 [P < .001]; Cohen d = 0.6; 23.3% higher), with a more prominent implication for the cannabis use disorder subgroup (n = 15; main group effect: F1,39 = 8.5 [P = .006]; ROI effect: F1,164 = 19.3 [P < .001]; Cohen d = 0.8; 31.5% higher). Greater TSPO levels in the brain were associated with stress and anxiety and with higher circulating C-reactive protein levels in cannabis users.

CONCLUSIONS AND RELEVANCE

The results of this study suggest that TSPO levels in cannabis users, particularly in those with cannabis use disorder, are higher than those in non-cannabis-using controls. The findings emphasize the need for more complementary preclinical systems for a better understanding of the role of cannabinoids and TSPO in neuroimmune signaling.

Cannabis Influences the Putative Cytokines-Related Pathway of Epilepsy among Egyptian Epileptic Patients

The study aims to investigate: (1) the prevalence of cannabis among epileptic patients seen at Mansoura University Hospital, (2) serum levels and gene expression of cytokines in epilepsy patients and the controls. and (3) the possibility that cannabis use affects the cytokine levels in epilepsy patients, triggering its future use in treatment. We recruited 440 epilepsy patients and 200 controls matched for age, gender, and ethnicity. Of the epileptic patients, 37.5% demonstrated lifetime cannabis use with a mean duration of 15 ± 73 years. Serum levels of interleukin IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, and tumor necrosis factor-α (TNF-α), were analyzed and gene expression analysis was conducted only for those cytokines that were different between groups in the serum analysis. The “Epilepsy-only” patients had significantly higher serum and mRNA levels of IL-1α, β, IL-2,6,8, and TNF-α compared to the controls and the “Cannabis+Epilepsy” group (p = 0.0001). IL-10 showed significantly lower levels in the “Epilepsy-only” patients compared to the controls and “Cannabis+Epilepsy” (p = 0.0001). Cannabis use is prevalent among epilepsy patients. Epilepsy is characterized by a pro-inflammatory state supported by high serum and gene expression levels. Cannabis users demonstrated significantly lower levels of inflammatory cytokines compared to epilepsy non-cannabis users which might contribute to its use in the treatment of resistant epilepsy.

Cannabinoid Receptor 2 (CB2) Signals via G-alpha-s and Induces IL-6 and IL-10 Cytokine Secretion in Human Primary Leukocytes

Cannabinoid receptor 2 (CB₂) is a promising therapeutic target for immunological modulation. There is, however, a deficit of knowledge regarding CB₂ signaling and function in human primary immunocompetent cells. We applied an experimental paradigm which closely models the in situ state of human primary leukocytes (PBMC; peripheral blood mononuclear cells) to characterize activation of a number of signaling pathways in response to a CB₂-selective ligand (HU308). We observed a "lag" phase of unchanged cAMP concentration prior to development of classically expected Gα_i-mediated inhibition of cAMP synthesis. Application of G protein inhibitors revealed that this apparent lag was a result of counteraction of Gα_i effects by concurrent Gα_s activation. Monitoring downstream signaling events showed that activation of p38 was mediated by Gα_i, whereas ERK1/2 and Akt phosphorylation were mediated by Gα_i-coupled βγ. Activation of CREB integrated multiple components; Gα_s and βγ mediated ∼85% of the response, while ∼15% was attributed to Gα_i. Responses to HU308 had an important functional outcome-secretion of interleukins 6 (IL-6) and 10 (IL-10). IL-2, IL-4, IL-12, IL-13, IL-17A, MIP-1α, and TNF-α were unaffected. IL-6/IL-10 induction had a similar G protein coupling profile to CREB activation. All response potencies were consistent with that expected for HU308 acting via CB₂. Additionally, signaling and functional effects were completely blocked by a CB₂-selective inverse agonist, giving additional evidence for CB₂ involvement. This work expands the current paradigm regarding cannabinoid immunomodulation and reinforces the potential utility of CB₂ ligands as immunomodulatory therapeutics.

Supraphysiologic-dose anabolic-androgenic steroid use: A risk factor for dementia?

Supraphysiologic-dose anabolic-androgenic steroid (AAS) use is associated with physiologic, cognitive, and brain abnormalities similar to those found in people at risk for developing Alzheimer's Disease and its related dementias (AD/ADRD), which are associated with high brain β-amyloid (Aβ) and hyperphosphorylated tau (tau-P) protein levels. Supraphysiologic-dose AAS induces androgen abnormalities and excess oxidative stress, which have been linked to increased and decreased expression or activity of proteins that synthesize and eliminate, respectively, Aβ and tau-P. Aβ and tau-P accumulation may begin soon after initiating supraphysiologic-dose AAS use, which typically occurs in the early 20s, and their accumulation may be accelerated by other psychoactive substance use, which is common among non-medical AAS users. Accordingly, the widespread use of supraphysiologic-dose AAS may increase the numbers of people who develop dementia. Early diagnosis and correction of sex-steroid level abnormalities and excess oxidative stress could attenuate risk for developing AD/ADRD in supraphysiologic-dose AAS users, in people with other substance use disorders, and in people with low sex-steroid levels or excess oxidative stress associated with aging.

Neuroinflammation in addiction: A review of neuroimaging studies and potential immunotherapies

Addiction is a worldwide public health problem and this article reviews scientific advances in identifying the role of neuroinflammation in the genesis, maintenance, and treatment of substance use disorders. With an emphasis on neuroimaging techniques, this review examines human studies of addiction using positron emission tomography to identify binding of translocator protein (TSPO), which is upregulated in reactive glial cells and activated microglia during pathological states. High TSPO levels have been shown in methamphetamine use but exhibits variable patterns in cocaine use. Alcohol and nicotine use, however, are associated with lower TSPO levels. We discuss how mechanistic differences at the neurotransmitter and circuit level in the neural effects of these agents and subsequent immune response may explain these observations. Finally, we review the potential of anti-inflammatory drugs, including ibudilast, minocycline, and pioglitazone, to ameliorate the behavioral and cognitive consequences of addiction.