Cocaine infusion increases interferon-gamma and decreases interleukin-10 in cocaine-dependent subjects

Role of Microglia in Psychostimulant Addiction

The use of psychostimulant drugs can modify brain function by inducing changes in the reward system, mainly due to alterations in dopaminergic and glutamatergic transmissions in the mesocorticolimbic pathway. However, the etiopathogenesis of addiction is a much more complex process. Previous data have suggested that microglia and other immune cells are involved in events associated with neuroplasticity and memory, which are phenomena that also occur in addiction. Nevertheless, how dependent is the development of addiction on the activity of these cells? Although the mechanisms are not known, some pathways may be involved. Recent data have shown psychoactive substances may act directly on immune cells, alter their functions and induce various inflammatory mediators that modulate synaptic activity. These could, in turn, be involved in the pathological alterations that occur in substance use disorder. Here, we extensively review the studies demonstrating how cocaine and amphetamines modulate microglial number, morphology, and function. We also describe the effect of these substances in the production of inflammatory mediators and a possible involvement of some molecular signaling pathways, such as the toll-like receptor 4. Although the literature in this field is scarce, this review compiles the knowledge on the neuroimmune axis that is involved in the pathogenesis of addiction, and suggests some pharmacological targets for the development of pharmacotherapy.

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.

Histopathological and inflammatory response in multiple organs of rats exposed to crack

The aim of this study was to investigate histopathological and inflammatory response in liver and kidney of rats after crack exposure. For this purpose, a total of 32 male Wistar rats were distributed into four groups: (G1) and (G2): received 18 mg/kg of body weight (b.w) of crack cocaine, but Group G2 remained 72 h without exposure after the experimental period (5 days). Experimental group 3 (G3): received 36 mg/kg of body weight (b.w) of crack cocaine. Control Group (CTRL): received only the vehicle (DMSO) administered by intraperitoneal (i.p) route for 5 days. The results showed that crack cocaine induced histopathological changes in liver and kidney. Immunohistochemistry data revealed that G2 group showed a higher immunoexpression of Ki-67 in hepatic and renal tissues. Regarding inflammation, the results showed that all groups exposed to crack cocaine decreased the expression of TNF-α, IL-6, and IL-10 in liver and kidney. In summary, our results showed that the subacute doses of crack cocaine used in this study had cytotoxic, and immunosuppressive effects in liver and kidney of rats, especially at 36 mg/kg dose. Since cellular death and inflammation participates in the multi-step process of chemical carcinogenesis, these data offer new insights into potential ways to understand the pathobiological mechanisms induced by crack cocaine in several tissues and organs.

Oral Enrichment of Streptococcus and its Role in Systemic Inflammation Related to Monocyte Activation in Humans with Cocaine Use Disorder

Cocaine use is commonly associated with increased chronic systemic inflammation. However, the drivers for cocaine use-mediated systemic inflammation are not fully understood. In the current study, we recruited individuals with cocaine use disorder and healthy individuals who did not use cocaine and collected paired saliva and blood samples. The saliva samples were used to assess the oral microbiome, and the plasma samples were evaluated for 33 cytokines and chemokines. Cocaine users exhibited decreased saliva microbial diversities compared to non-users. Streptococcus was the only increased genus in the saliva from cocaine users, whereas several genera were decreased in cocaine users compared to non-users. Notably, cocaine users exhibited increased plasma levels of several monocyte activation markers, including monocyte chemoattractant protein (MCP)-4, macrophage inflammatory protein (MIP)-3α, macrophage-derived chemokine (MDC), and thymus and activation-regulated chemokine (TARC), all of which were correlated with increased saliva levels of three Streptococcus species. Furthermore, treatment with Streptococcus or its lipoteichoic acid preferentially activated primary human monocytes to produce proinflammatory cytokines and chemokines, such as MIP-3α and TARC, in vitro compared to controls. However, monocytes failed to produce these chemokines after exposure to cocaine or cocaine plus bacteria compared to medium or bacteria alone. This study revealed that chronic cocaine use-associated inflammation in the blood may result from increased oral Streptococcus and its effects on myeloid cell activation, but does not result from cocaine directly.

Transplantation with Lewis bone marrow induces the reinstatement of cocaine-seeking behavior in male F344 resistant rats

One of the main challenges to understand drug addiction is defining the biological mechanisms that underlie individual differences in recidivism. Studies of these mechanisms have mainly focused on the brain, yet we demonstrate here a significant influence of the peripheral immune system on this phenomenon. Lewis (LEW) and Fischer 344 (F344) rats have different immunological profiles and they display a distinct vulnerability to the reinforcing effects of cocaine, with F344 more resistant to reinstate cocaine-seeking behavior. Bone marrow from male LEW and F344 rats was transferred to male F344 rats (F344/LEW-BM and F344/F344-BM, respectively), and these rats were trained to self-administer cocaine over 21 days. Following extinction, these animals received a sub-threshold primer dose of cocaine to evaluate reinstatement. F344/LEW-BM but not F344/F344-BM rats reinstated cocaine-seeking behavior, in conjunction with changes in their peripheral immune cell populations to a profile that corresponded to that of the LEW donors. After cocaine exposure, higher CD4⁺ T-cells and lower CD4⁺CD25⁺ T-cells levels were observed in F344/LEW-BM rats referred to control, and the splenic expression of Il-17a, Tgf-β, Tlr-2, Tlr-4 and Il-1β was altered in both groups. We propose that peripheral T-cells respond to cocaine, with CD4⁺ T-cells in particular undergoing Th17 polarization and generating long-term memory, these cells releasing mediators that trigger central mechanisms to induce reinstatement after a second encounter. This immune response may explain the high rates of recidivism observed despite long periods of detoxification, shedding light on the mechanisms underlying the vulnerability and resilience of specific individuals, and opening new perspectives for personalized medicine in the treatment of relapse.

Cocaine Use Disorder Is Associated With Changes in Th1/Th2/Th17 Cytokines and Lymphocytes Subsets

Background: Cocaine is a psychostimulant drug with high addictive proprieties. Evidence suggests that cocaine use leads to critical changes in the immune system, with significant effects on T, B, and natural killer (NK) cells and influencing peripheral levels of cytokines. The presence of abstinence-related symptoms during detoxification treatment is known to influence the prognosis. Here, our aim was to investigate immune profiles in women with cocaine use disorder (CUD) according to withdrawal symptoms severity.

Methods: Blood samples and clinical data were collected at onset of detoxification treatment of 50 women with CUD. The patients were stratified according to Cocaine Selective Severity Assessment (CSSA) scores in low withdrawal (L-W) and high withdrawal (H-W) categories. In addition, we also included a control group with 19 healthy women as reference to immune parameters. Peripheral blood was collected and lymphocyte subsets were phenotyped by multi-color flow cytometry (B cells, CD4⁺ T, CD8⁺ T, NK cells, and different stages of T-cell differentiation). PBMCs from patients and healthy controls were stimulated in vitro with phytohemagglutinin (1%) for 72 h to assess the production of Th1/Th2/Th17 cytokines.

Results: Following stimulation, lymphocytes from women with CUD produced increased levels of Th1/Th2/Th17 cytokines. However, higher levels of IL-2 and IL-17 were observed only in the L-W group, while higher levels of IL-6 were detected in the H-W group compared to controls. H-W group showed lower percentage of early-differentiated Th cells (CD4⁺CD27⁺CD28⁺), elevated percentage of Th cells (CD3⁺CD4⁺), intermediate-differentiated Th cells (CD4⁺CD27⁻CD28⁺), and B cells (CD3⁻CD19⁺). Both CUD groups showed decreased percentages of naïve T cells (CD3⁺CD4⁺CD45RA⁺ and CD3⁺CD8⁺CD45RA⁺).

Conclusion: Our data demonstrated that CUD can lead to increased production of Th1/Th2/Th17 cytokines and lymphocyte changes.

Distinct inflammatory profiles in HIV-infected individuals under antiretroviral therapy using cannabis, cocaine or cannabis plus cocaine

OBJECTIVES

To evaluate the effects of cannabis and/or cocaine use on inflammatory, oxidative stress status and circulating monocyte subsets in HIV-infected individuals under antiretroviral therapy.

DESIGN

Soluble CD14 (sCD14), intestinal fatty acid-binding protein (IFABP), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-8, IL-10, C-reactive protein (CRP) and oxidative stress markers were examined. The monocyte subsets and their activation and cytokine production by peripheral blood mononuclear cells (PBMCs) of HIV-1 infected individuals upon lipopolysaccharide (LPS)-stimulation were also investigated.

METHODS

sCD14, IFABP, TNF-α, IL-6, IL-8 and IL-10 levels were evaluated using ELISA, CRP by turbidimetry; lipid peroxidation (TBARS) spectrofluometrically and total thiol levels by using 5-5'-dithio-bis (2-nitrobenzoic acid) reagent. Monocyte subsets and activation were assessed by flow cytometry.

RESULTS

All HIV-infected drug user groups showed higher sCD14 levels compared with HIV+ nondrug users. IFABP was increased in HIV+ drug-users in relation to healthy individuals. Cannabis use lowered the percentages of inflammatory, nonclassical, activated-classic and activated-inflammatory monocytes. Cocaine users showed increased plasmatic TNF-α and TBARS levels, decreased thiols content and lower activated-classic and inflammatory-monocyte percentages. Cannabis-plus-cocaine use increased CRP, IL-8 and IL-6/IL-10 ratio, but decreased thiol content, and inflammatory and activated-classic monocyte percentages. PBMCs of cannabis and cannabis-plus-cocaine users showed low-potential cytokine production either spontaneously or under LPS-stimulation.

CONCLUSION

In HIV infection, the use of cannabis induces predominantly an anti-inflammatory profile. The use of cocaine and cannabis-plus-cocaine showed a mixed pro-inflammatory and anti-inflammatory profile, with predominance of inflammatory status. Further studies are required to better understand the action of these drugs in HIV infection.

Drugs of Abuse Induced-Subversion of the Peripheral Immune Response and Central Glial Activity: Focus on Novel Therapeutic Approaches

BACKGROUND

Drugs of abuse affect both central nervous system (CNS) and peripheral immune function. Besides the involvement of dopamine and glutamate systems, chronic exposure to drugs of abuse alters immune homeostasis, promoting a pro-inflammatory status. At the same time, impaired peripheral immunity leads to an increased susceptibility to infections in drug abusers.

DISCUSSION

There is evidence that certain drugs, such as opioids, activate microglial cells and astrocytes which, in turn, provoke central neuroinflammation. Particularly, opioids bind the Toll-like receptor (TLR)-4 with increased expression of nuclear factor kappa-light-chain-enhancer of activated B cells and release of pro-inflammatory cytokines. Peripheral mediators released by immune cells also contribute to aggravate central neuroinflammation.

CONCLUSION

These are based either on the inhibition of TLR-4 activation by drugs of abuse or on the correction of dopamine and glutamate pathways. Finally, a hypothetic nutraceutical intervention with polyphenols in view of their anti-inflammatory and anti-oxidant properties will be outlined as an adjuvant treatment for drugs of abuse-related disorders.

Exosome markers associated with immune activation and oxidative stress in HIV patients on antiretroviral therapy

Exosomes are nanovesicles released from most cell types including immune cells. Prior studies suggest exosomes play a role in HIV pathogenesis, but little is known about exosome cargo in relation to immune responses and oxidative stress. Here, we characterize plasma exosomes in HIV patients and their relationship to immunological and oxidative stress markers. Plasma exosome fractions were isolated from HIV-positive subjects on ART with suppressed viral load and HIV-negative controls. Exosomes were characterized by electron microscopy, nanoparticle tracking, immunoblotting, and LC-MS/MS proteomics. Plasma exosomes were increased in HIV-positive subjects compared to controls, and correlated with increased oxidative stress markers (cystine, oxidized cys-gly) and decreased PUFA (DHA, EPA, DPA). Untargeted proteomics detected markers of exosomes (CD9, CD63, CD81), immune activation (CD14, CRP, HLA-A, HLA-B), oxidative stress (CAT, PRDX1, PRDX2, TXN), and Notch4 in plasma exosomes. Exosomal Notch4 was increased in HIV-positive subjects versus controls and correlated with immune activation markers. Treatment of THP-1 monocytic cells with patient-derived exosomes induced expression of genes related to interferon responses and immune activation. These results suggest that exosomes in ART-treated HIV patients carry proteins related to immune activation and oxidative stress, have immunomodulatory effects on myeloid cells, and may have pro-inflammatory and redox effects during pathogenesis.

More inflammation but less brain-derived neurotrophic factor in antisocial personality disorder

Antisocial personality disorder (ASPD) is highly comorbid with substance use disorders (SUDs). We hypothesize that chronic neuroinflammation and the loss of neurotrophic factors prompts the pathogenesis of both disorders. We used ELISA to measure plasma levels of proinflammatory (tumor necrosis factor-α [TNF-α], C-reactive protein [CRP]) and anti-inflammatory factors (transforming growth factor-β1 [TGF-β1] and interleukin-10 [IL-10]), and brain-derived neurotrophic factor (BDNF) in male patients with ASPD (n=74), SUDs (n=168), ASPD comorbid with SUDs (ASPD+SUDs) (n=438), and Healthy Controls (HCs) (n=81). A multivariate analysis of covariance (MANCOVA) controlled for possible confounders was used to compare cytokines and BDNF levels between groups. The results of MANCOVA adjusted for age showed a significant (p<0.001) main effect of diagnosis on inflammatory factors and BDNF expression in these groups. ASPD, SUDs, and ASPD+SUDs patients had significantly (p<0.001) higher TNF-α levels but lower TGF-β1 and BDNF levels. SUDs and ASPD+SUDs patients had higher IL-10 levels than did ASPD patients and HCs. There was no difference in IL-10 levels between HCs and ASPD. Moreover, subgrouping SUDs and ASPD±SUDs into opioid use disorder (OUD) and other SUDs groups showed that the IL-10 levels were specifically higher in OUD and ASPD±OUD groups than other SUDs (P≤0.001). We conclude that uncontrolled inflammation and losing neurotrophic factors, with or without comorbid SUDs, underlies ASPD. IL-10 expression might be more specifically associated with OUD.

Differences in biomarkers of crack-cocaine adolescent users before/after abstinence

AIMS

To measure the variation in Brain-Derived Neurotrophic Factor (BDNF), Thiobarbituric Acid Reactive Substances (TBARS) and interleukin (IL) levels in crack-cocaine dependent adolescents after 21days of abstinence, comparing to levels found in a group of healthy controls.

DESIGN

Cross-sectional nested on a short follow-up study.

SETTING

Two inpatient treatment units for adolescents, and a low-income neighborhood.

PARTICIPANTS

90 adolescents, of both genders, with diagnosis of crack cocaine dependence, and 81 healthy adolescents.

MEASUREMENTS

Serum levels of IL-6, IL-10, TBARS and BDNF were assessed on admission and discharge. Drug addiction severity was assessed by the Addiction Severity Index - Teen Version (T-ASI) and Cocaine Craving Questionnaire - Brief version (CCQ-b). Psychiatric comorbidities were assessed by the Schedule for Affective Disorders and Schizophrenia for School-Age Children - Present and Lifetime Version (K-SADS-PL). Generalized Estimating Equations (GEE) were used to estimate the IL-6, IL-10, TBARS and BDNF levels, adjusted for confounders. Hedges' g was used to estimate effect size.

FINDINGS

TBARS (p=0.005, d=0.04), IL-6 (p=0.027, d=0.40) and IL-10 (p=0.025, d=0.41) were elevated and BDNF (p<0.001, d=0.62) was reduced (p<0.001), in patients, in comparison to controls, at admission time. Variation in those levels between admission and discharge were not significant.

CONCLUSIONS

Crack-cocaine use seems to be associated with inflammatory and oxidative imbalances in adolescents.

Effects of amphetamine and cocaine on the development of acute experimental allergic encephalomyelitis in Lewis rats

The present experiment deals with the effects of amphetamine and cocaine on the development and course of experimental allergic encephalomyelitis (EAE) induced in Lewis rats. Rats were immunized at the age of eight weeks with purified myelin basic protein isolated from guinea pig brain in complete Freund's adjuvant. Drug administration and recording of EAE clinical signs was performed daily since day 1 post-immunization (PI). On day 14 and 28 PI, six rats per group were bled and sacrificed. Spinal cord was examined histologically for EAE lesions. In vivo administration of 0.5 and 1 mg/Kg of amphetamine or cocaine resulted in a dose-related enhancement of neurological and histological signs of acute EAE in comparison with control rats. Both drugs caused a reduction of latent period together with a delayed regression of neurological signs along with an increase in inflammation in the central nervous system in comparison with placebo. Human & Experimental Toxicology (2007) 26, 637—643

Cocaine abuse and effects in the serum levels of cytokines IL-6 and IL-10

BACKGROUND

Cocaine abuse is capable of activating the innate immune system in the CNS resulting in deregulation of homeostasis between pro and antiinflammatory cytokines. The aim of this study was to investigate serum levels of pro and antiinflammatory cytokines, IL-6 and IL-10 respectively, in cocaine users from a young population-based sample.

METHODS

This is a case-control study nested in a cross-sectional population-based survey, with individuals of 18 and 35 years old. Two groups were selected: 24 healthy controls and 12 subjects who reported cocaine use. Serum IL-6 and IL-10 were measured by ELISA using a commercial kit.

RESULTS

There was a statistically significant increase in IL-6 (p=0.037) and decrease in IL-10 (p=0.007) serum levels, between cocaine users and the control group. There was also an increase in the ratio IL-6/IL-10 (p=0.013) among cocaine users individuals, when compared to the control group.

CONCLUSIONS

Our results suggest that cocaine users showed an activation of the immune system when compared a control group, demonstrating a disruption in the balance of pro and antiinflammatory cytokines. Thus, peripheral cytokines may represent a putative biomarkers for cocaine users, contributing to the development of diagnosis and effective treatments.

Cocaine-mediated impact on HIV infection in humanized BLT mice

Cocaine abuse has been shown to have broad-ranging effects on human immunity. With regards to HIV infection, in vitro studies have shown that cocaine enhances infection of stimulated lymphocytes. Moreover, cohort studies in the pre- and post-HAART era have linked stimulant abuse with increased HIV pathogenesis. The latter data, however, have been undermined by a series of confounding factors underscoring the importance of controlled in vivo models to fully assess the impact of cocaine use and abuse on HIV infection and pathogenesis. Here, we have infected humanized mice with HIV-1 following acute cocaine exposure to assess the impact on infection. Stimulant exposure resulted in increased inflammatory cytokine expression, accelerated HIV infection, while blunting effector function of cytotoxic T lymphocytes. These data demonstrate cocaine’s multifactorial impact on HIV infection that extends beyond high-risk behavior.

Neuroinflammation as a possible link between cannabinoids and addiction

OBJECTIVE

Substance dependence disorder is a chronically relapsing condition characterised by neurobiological changes leading to loss of control in restricting a substance intake, compulsion and withdrawal syndrome. In the past few years, (endo)cannabinoids have been raised as a possible target in the aetiology of drug addiction. On the other hand, although the exact mechanisms of the genesis of addiction remain poorly understood, it is possible that neuroinflammation might also play a role in the pathophysiology of this condition. Studies demonstrated that (endo)cannabinoids act as immunomodulators by inhibiting cytokines production and microglial cell activation. Thus, in the present review, we explore the possible role of neuroinflammation on the therapeutic effects of cannabinoids on drug addiction.

METHODS

We conducted an evidence-based review of the literature in order to assess the role of cannabinoids on the neuroinflammatory hypothesis of addiction (terms: addiction, cannabinoids and inflammation). We searched PubMed and BioMedCentral databases up to April 2014 with no date restrictions.

RESULTS

In all, 165 eligible articles were included in the present review. Existing evidence suggests that disruption in cannabinoid signalling during the drug addiction process leads to microglial activation and neuroinflammation.

CONCLUSION

The literature showed that inflammation and changes in endocannabinod signalling occur in drug abuse; however, it remains uncertain whether these changes are causally or coincidentally associated with addiction. Additional studies, therefore, are needed to elucidate the contribution of neuroinflammation on the behavioural and neuroprotective effects of cannabinoids on drug addiction.

Systems-level view of cocaine addiction: the interconnection of the immune and nervous systems

The human body is a complex assembly of physiological systems designed to manage the multidirectional transport of both information and nutrients. An intricate interplay between the nervous, circulatory, and secretory systems is therefore necessary to sustain life, allow delivery of nutrients and therapeutic drugs, and eliminate metabolic waste products and toxins. These systems also provide vulnerable routes for modification by substances of abuse. Addictive substances are, by definition, neurologically active, but as they and their metabolites are spread throughout the body via the nervous, circulatory, respiratory and digestive systems, there is abundant opportunity for interaction with numerous cell and tissue types. Cocaine is one such substance that exerts a broad physiological effect. While a great deal of the research concerning addiction has addressed the neurological effects of cocaine use, only a few studies have been aimed at delineating the role that cocaine plays in various body systems. In this paper, we probe the current research regarding cocaine and the immune system, and map a systems-level view to outline a broader perspective of the biological response to cocaine. Specifically, our overview of the neurological and immunomodulatory effects of the drug will allow a broader perspective of the biological response to cocaine. The focus of this review is on the connection between the nervous and immune systems and the role this connection plays in the long-term complications of cocaine use. By describing the multiplicity of these connections, we hope to inspire detailed investigations into the immunological interplay in cocaine addiction.

Adipokines during early abstinence of crack cocaine in dependent women reporting childhood maltreatment

Childhood maltreatment has been associated with addiction and immune dysregulation, although neurobiological substrates underlying this association remain largely unknown. The aim of the study was to compare plasma levels of adipokines during early abstinence in crack cocaine dependent women with (CM+) and without history of childhood maltreatment (CM-). One hundred four crack cocaine female users were followed for 20 days in a detoxification inpatient treatment unit. Plasma levels of adiponectin, resistin and leptin were assessed every 7 days during 3 weeks of follow-up. The Childhood Trauma Questionnaire (CTQ) retrospectively assessed childhood maltreatment history. A healthy control group was included to provide adipokines reference values (HC). All crack users increased leptin plasma levels during early abstinence despite concentrations remained lower in comparison with non-users group. Crack users reporting childhood maltreatment exhibited a significant reduction in plasma levels of adiponectin and resistin when compared to CM- group. In addition, only CM- participants increased plasma levels of adiponectin during detoxification. This is the first study evaluating adipokines during crack cocaine abstinence. Our results suggest a modulator effect of childhood maltreatment on inflammatory status in treatment-seeking crack cocaine dependents during early abstinence.

Applications and limitations of inflammatory biomarkers for studies on neurocognitive impairment in HIV infection

Despite reduced prevalence of severe forms of HIV-associated neurocognitive disorders (HAND) on current antiretroviral therapy (ART) regimens, milder forms of neurocognitive impairment (NCI) remain prevalent in HIV-infected populations. These mild forms of HAND consist of subtypes, probably reflecting distinct, though possibly overlapping, pathophysiological mechanisms. Factors associated with HAND in HIV patients with prolonged viral suppression on ART include older age, low nadir CD4, active HCV co-infection, and cardiovascular risk factors, but underlying mechanisms and their relationship to innate immune activation, chronic inflammation, and other features of systemic disease are poorly understood. In this article, we discuss applications and limitations of plasma inflammatory biomarkers for studies on HAND in HIV patients on ART and describe an analysis pipeline to reduce common sources of noise and increase likelihood of identifying relevant inflammatory biomarkers. Clinical covariates and comorbidities that influence inflammatory biomarkers, such as aging, obesity, metabolic abnormalities, HCV co-infection, and substance abuse, are also reviewed. As an example for using this analytic pipeline, we present an exploratory study of 22 plasma inflammatory biomarkers (IFN-α 2b and -γ, 16 cytokines/chemokines, sIL-2R, sCD14, HA, and YKL-40) in a cohort of HIV-infected individuals with advanced disease, frequent HCV co-infection, and viral suppression on ART. The identification of inflammatory biomarkers associated with HAND in HIV+ patients on ART may be useful to distinguish between HAND subtypes with distinct pathophysiology, and is important for achieving a systems-level understanding of the biology of these disorders, developing effective therapies, and evaluating therapeutic outcomes.

Substance use disorders: psychoneuroimmunological mechanisms and new targets for therapy

An estimated 76.4 million people worldwide meet criteria for alcohol use disorders, and 15.3 million meet criteria for drug use disorders. Given the high rates of addiction and the associated health, economic, and social costs, it is essential to develop a thorough understanding of the impact of substance abuse on mental and physical health outcomes and to identify new treatment approaches for substance use disorders (SUDs). Psychoneuroimmunology is a rapidly expanding, multidisciplinary area of research that may be of particular importance to addiction medicine, as its focus is on the dynamic and complex interactions among behavioral factors, the central nervous system, and the endocrine and immune systems (Ader, 2001). This review, therefore, focuses on: 1) the psychoneuroimmunologic effects of SUDs by substance type and use pattern, and 2) the current and future treatment strategies, including barriers that can impede successful recovery outcomes. Evidence-based psychosocial and pharmacotherapeutic treatments are reviewed. Psychological factors and central nervous system correlates that impact treatment adherence and response are discussed. Several novel therapeutic approaches that are currently under investigation are introduced; translational data from animal and human studies is presented, highlighting immunotherapy as a promising new direction for addiction medicine.

Cocaine and HIV-1 interplay in CNS: cellular and molecular mechanisms

Although antiretrovirals are the mainstay of therapy against HIV infection, neurological complications associated with the virus continue to hamper quality of life of the infected individuals. Drugs of abuse in the infected individuals further fuel the epidemic. Epidemiological studies have demonstrated that abuse of cocaine resulted in acceleration of HIV infection and the progression of NeuroAIDS. Cocaine has not only been shown to play a crucial role in promoting virus replication, but also has diverse but often deleterious effects on various cell types of the CNS. In the neuronal system, cocaine exposure results in neuronal toxicity and also potentiates gp120-induced neurotoxicity. In the astroglia and microglia, cocaine exposure leads to up-regulation of pro-inflammatory mediators such as cytokines and chemokines. These in turn, can lead to neuroinflammation and transmission of toxic responses to the neurons. Additionally, cocaine exposure can also lead to leakiness of the blood-brain barrier that manifests as enhanced transmigraiton of leukocytes/monocytes into the CNS. Both in vitro and in vivo studies have provided valuable tools in exploring the role of cocaine in mediating HIV-associated neuropathogenesis. This review summarizes previous studies on the mechanism(s) underlying the interplay of cocaine and HIV as it relates to the CNS.

A plasma biomarker signature of immune activation in HIV patients on antiretroviral therapy

BACKGROUND

Immune activation is a strong predictor of disease progression in HIV infection. Combinatorial plasma biomarker signatures that represent surrogate markers of immune activation in both viremic and aviremic HIV patients on combination antiretroviral therapy (cART) have not been defined. Here, we identify a plasma inflammatory biomarker signature that distinguishes between both viremic and aviremic HIV patients on cART and healthy controls and examine relationships of this signature to markers of disease progression.

METHODS

Multiplex profiling and ELISA were used to detect 15 cytokines/chemokines, soluble IL-2R (sIL-2R), and soluble CD14 (sCD14) in plasma from 57 HIV patients with CD4 nadir <300 cells/µl and 29 healthy controls. Supervised and unsupervised analyses were used to identify biomarkers explaining variance between groups defined by HIV status or drug abuse. Relationships between biomarkers and disease markers were examined by Spearman correlation.

RESULTS

The majority (91%) of HIV subjects were on cART, with 38% having undetectable viral loads (VL). Hierarchical clustering identified a biomarker cluster in plasma consisting of two interferon-stimulated gene products (CXCL9 and CXCL10), T cell activation marker (sIL-2R), and monocyte activation marker (sCD14) that distinguished both viremic and aviremic HIV patients on cART from controls (p<0.0001) and were top-ranked in variables important in projection plots. IL-12 and CCL4 were also elevated in viremic and aviremic patients compared to controls (p<0.05). IL-12 correlated with IFNα, IFNγ, CXCL9, and sIL-2R (p<0.05). CXCL10 correlated positively with plasma VL and percentage of CD16+ monocytes, and inversely with CD4 count (p = 0.001, <0.0001, and 0.04, respectively).

CONCLUSION

A plasma inflammatory biomarker signature consisting of CXCL9, CXCL10, sIL-2R, and sCD14 may be useful as a surrogate marker to monitor immune activation in both viremic and aviremic HIV patients on cART during disease progression and therapeutic responses.

Implications of central immune signaling caused by drugs of abuse: mechanisms, mediators and new therapeutic approaches for prediction and treatment of drug dependence

In the past two decades a trickle of manuscripts examining the non-neuronal central nervous system immune consequences of the drugs of abuse has now swollen to a significant body of work. Initially, these studies reported associative evidence of central nervous system proinflammation resulting from exposure to the drugs of abuse demonstrating key implications for neurotoxicity and disease progression associated with, for example, HIV infection. However, more recently this drug-induced activation of central immune signaling is now understood to contribute substantially to the pharmacodynamic actions of the drugs of abuse, by enhancing the engagement of classical mesolimbic dopamine reward pathways and withdrawal centers. This review will highlight the key in vivo animal, human, biological and molecular evidence of these central immune signaling actions of opioids, alcohol, cocaine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA). Excitingly, this new appreciation of central immune signaling activity of drugs of abuse provides novel therapeutic interventions and opportunities to identify 'at risk' individuals through the use of immunogenetics. Discussion will also cover the evidence of modulation of this signaling by existing clinical and pre-clinical drug candidates, and novel pharmacological targets. Finally, following examination of the breadth of central immune signaling actions of the drugs of abuse highlighted here, the current known common immune signaling components will be outlined and their impact on established addiction neurocircuitry discussed, thereby synthesizing a common neuroimmune hypothesis of addiction.

Breaking down the barrier: the effects of HIV-1 on the blood-brain barrier

Human immunodeficiency virus type 1 (HIV-1) primarily infects CD4(+) T cells and cells of the monocyte-macrophage lineage, resulting in immunodeficiency in an infected patient. Along with this immune deficiency, HIV-1 has been linked to a number of neurological symptoms in the absence of opportunistic infections or other co-morbidities, suggesting that HIV-1 is able to cross the blood-brain barrier (BBB), enter the central nervous system (CNS), and cause neurocognitive impairment. HIV-1-infected monocyte-macrophages traverse the BBB and enter the CNS throughout the course of HIV-1 disease. Once in the brain, both free virus and virus-infected cells are able to infect neighboring resident microglia and astrocytes and possibly other cell types. HIV-1-infected cells in both the periphery and the CNS give rise to elevated levels of viral proteins, including gp120, Tat, and Nef, and of host inflammatory mediators such as cytokines and chemokines. It has been shown that the viral proteins may act alone or in concert with host cytokines and chemokines, affecting the integrity of the BBB. The pathological end point of these interactions may facilitate a positive feedback loop resulting in increased penetration of HIV into the CNS. It is proposed in this review that the dysregulation of the BBB during and after neuroinvasion is a critical component of the neuropathogenic process and that dysregulation of this protective barrier is caused by a combination of viral and host factors including secreted viral proteins, components of the inflammatory process, the aging process, therapeutics, and drug or alcohol abuse.

Cocaine-mediated induction of platelet-derived growth factor: implication for increased vascular permeability

Neuroinflammation associated with advanced HIV-1 infection is often exacerbated in cocaine-abusing, HIV-infected patients. The underlying mechanisms could, in part, be attributed to the increased impairment of blood brain barrier integrity in the presence of cocaine. Platelet-derived growth factor (PDGF) has been implicated in several pathologic conditions, specifically attributable to its potent mitogenic effects. Its modulation by drug abuse, however, has received very little attention. In the present study, we demonstrated cocaine-mediated induction of PDGF-BB in human brain microvascular endothelial cells through the binding to its cognate σ receptor. Furthermore, this effect was mediated, with subsequent activation of mitogen-activated protein kinases and Egr-1 pathways, culminating ultimately into increased expression of PDGF-BB. Cocaine exposure resulted in increased permeability of the endothelial barrier, and this effect was abrogated in mice exposed to PDGF-BB neutralizing antibody, thus underscoring its role as a vascular permeant. In vivo relevance of these findings was further corroborated in cocaine-treated mice that were administered neutralizing antibody specific for PDGF-BB as well as in Egr-1(-/-) mice. Understanding the regulation of PDGF-BB expression may provide insights into the development of potential therapeutic targets for neuroinflammation associated with HIV infection and drug abuse.

Cocaine administration increases CD4/CD8 lymphocyte ratio in peripheral blood despite lymphopenia and elevated corticosterone

The CD4/CD8 lymphocyte ratio in peripheral blood is used in the diagnosis of HIV infection, autoimmune disorders or susceptibility to infections. The present experiment aimed to evaluate the lymphocyte subsets, their distribution and CD4/CD8 ratio in blood after repeated, intravenous administration of cocaine. Adult male Wistar rats received three daily, in 30 min intervals, intravenous infusions of cocaine hydrochloride (5 mg/kg) or saline for 14 consecutive days. After each infusion the locomotor-activating effects of cocaine were assessed. Blood samples were collected 30 min after the last daily infusion on the 1st, 7th and 14th day of treatment. Total leukocyte numbers, percentages of leukocyte subpopulations, and T, B, NK, T CD4+, and T CD8+ lymphocyte subsets, IFN-γ, and plasma corticosterone were determined. Repeated cocaine treatment resulted in an increase in neutrophil numbers and a significant decrease in total leukocyte and lymphocyte numbers involving a significant reduction in numbers of T, B, and NK lymphocyte subsets. T CD4+ and T CD8+ lymphocyte numbers were reduced but with a considerably smaller decrease in T CD4+ number. Cocaine treatment altered proportions between the lymphocyte subsets by decreasing the percentages of T CD8+, B, and NK cells but increasing a percentage of T CD4+ cells. Destabilization in proportions between T CD4+ and T CD8+ was manifested as an elevated CD4/CD8 ratio that occurred despite increased plasma corticosterone and the lymphocytopenia. Cocaine did not affect the concentration of IFN-γ. The results suggest that although cocaine induced lymphopenia, it did not suppress the overall immune activity in terms of the CD4/CD8 ratio.

Stimulant use is associated with immune activation and depleted tryptophan among HIV-positive persons on anti-retroviral therapy

Cocaine, crack, and methamphetamine are stimulants that promote autonomic nervous system activation. Although these stimulants may have immunomodulatory effects, relatively few studies have examined this possibility. The present cross-sectional investigation utilized baseline data from 127 HIV-positive individuals on anti-retroviral therapy (ART) that were enrolled in a randomized controlled trial. The goal of this study was to examine whether stimulant use is independently associated with immune activation and indices of tryptophan degradation. Forty-four participants reported using stimulants 2-3 times a month or more (i.e., monthly stimulant use) and a sub-set of these (n=27) reported using stimulants once a week or more (i.e., weekly stimulant use) during the past three months. These stimulant-using groups were compared to a group of participants who reported no stimulant use (n=83) during the past three months. Results indicated that individuals who reported either monthly or weekly stimulant use displayed elevated neopterin, a measure of immune activation. Those who reported weekly stimulant use also displayed a markedly elevated HIV viral load and lower tryptophan levels. Even after controlling for self-reported ART non-adherence, weekly stimulant use was independently associated with higher neopterin, elevated HIV viral load, and lower tryptophan. To our knowledge, this is the first study to observe that stimulant use may independently promote immune activation and tryptophan degradation among HIV-positive persons on ART. Further research is needed to replicate these findings and examine the plausible bio-behavioral pathways that may account for the effects of stimulant use on HIV disease markers and depleted tryptophan.

Cocaine dependence and acute cocaine induce decreases of monocyte proinflammatory cytokine expression across the diurnal period: autonomic mechanisms

Cocaine dependence is associated with an increased risk of infectious diseases. The innate immune system triggers effector pathways to combat microbial pathogens through expression of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). It is not known whether cocaine alters the capacity of monocytes to respond to a bacterial challenge in humans. In cocaine-dependent volunteers and control subjects, we analyzed monocyte TNF-alpha and IL-6 expression at rest and in response to the bacterial ligand, lipopolysaccharide (LPS), over a 24-h period. In addition, the in vivo effects of cocaine (40 mg) versus placebo on monocyte expression of TNF-alpha and IL-6 were profiled over 48 h. Cocaine-dependent volunteers showed a decrease in the capacity of monocytes to express TNF-alpha and IL-6 compared with control subjects. Moreover, acute infusion of cocaine induced a further decline in the responsiveness of monocytes to LPS, which persisted after cocaine had cleared from the blood. Heart rate variability analyses showed that increases of sympathetic activity along with vagal withdrawal were associated with decreases in monocyte expression of TNF-alpha. Cocaine alters autonomic activity and induces protracted decreases in innate immune mechanisms. Targeting sympathovagal balance might represent a novel strategy for partial amelioration of impairments of innate immunity in cocaine dependence.

Cocaine induced inflammatory response in human neuronal progenitor cells

We have employed a genomic approach in homogenous cell culture to investigate the fundamental transcriptional responses which occur in neurons over time as a consequence of a single 30-min exposure to cocaine. Data from 24 Affymetrix microarrays, representing eight treatment groups, were analyzed by GeneChip Operating Software and then further mined by hierarchical clustering, anova, and Ingenuity Pathway Analysis software to examine known molecular pathways impacted by the observed transcriptional changes. For each time point under investigation, the data sets of genes exhibiting altered expression in treated cells compared with control were interrogated with a specific focus on differential expression of genes involved in immunomodulation and inflammation. The existing literature on the effects of cocaine in a diverse array of experimental paradigms demonstrates a significant modulation of inflammation and immune mechanisms, but these have typically been studies of chronic exposure in immune-competent cells. Our data show a time-dependent up-regulation of genes associated with pro-inflammatory and immune responses, peaking at 24 h as confirmed by all methods of analysis, suggesting a specific neuronal immunomodulatory response to acute cocaine exposure.

Cocaine increases human immunodeficiency virus type 1 neuroinvasion through remodeling brain microvascular endothelial cells

Cocaine is a suspected cofactor in human immunodeficiency virus (HIV)-associated dementia but cocaine's effects are not clear. Herein the authors describe investigations of the mechanisms by which cocaine increases HIV-1 invasion through brain microvascular endothelial cells (BMVECs). Cocaine binds to a site on BMVECs, which is not a biogenic amine transporter, a binding site for estrogen, or a muscarinic receptor and for which benztropine and tamoxifen have the highest affinity. Cocaine treatment of BMVECs disrupts intercellular junctions and induces cell ruffling, which could account for their increased permeability and decreased electrical resistance. HIV-1 enters BMVECs by macropinocytosis and is transported to lysosomes and inactivated. In cocaine-treated BMVECs, the virus enters and persists in large cytoplasmic "lakes." Cocaine exposure of BMVECs up-regulates transcription of genes important in cytoskeleton organization, signal transduction, cell swelling, vesicular trafficking, and cell adhesion. The toxicity of cocaine for the blood-brain barrier may lead to increased virus neuroinvasion and neurovascular complications of cocaine abuse.

Dopamine by itself activates either D2, D3 or D1/D5 dopaminergic receptors in normal human T-cells and triggers the selective secretion of either IL-10, TNFalpha or both

The neurotransmitter dopamine on its own increased significantly TNFalpha and IL-10 secretion by resting normal-human T-cells, and induced approximately 5-fold elevation of the corresponding mRNA's, without affecting IFNgamma and IL-4. Using seven highly selective dopamine-receptor (DR) agonists and antagonists we found that TNFalpha-upregulation, evident after 24 h, was mediated by D3R and D1/D5R while IL-10-upregulation, evident after 72 h, was mediated by D2R and D1/D5R. We confirmed the expression of D2R and D3R in these human T cells. Dopamine's unique ability to trigger a selective secretion of either TNFalpha only (via D3R) or IL-10 only (via D2R) or both (via D1/D5R), differs from the robust and non-selective cytokine-secretion induced by 'classical' TCR-activation, and as such may have important beneficial or detrimental implications in various immunological and neurological diseases/injuries/cancers.

The effect of cocaine sensitization on mouse immunoreactivity

Recent studies indicate a role of the immune system in the behavioral effects of cocaine in rodents. In the present study, we attempted to find a correlation between the behavioral changes induced by repeated, intermittent administration of cocaine and some immunological consequences of sensitization to cocaine. Male Albino Swiss mice were treated repeatedly (for 5 days) with cocaine (10 or 15 mg/kg, intraperitoneally, ip). On day 9, they received a challenge dose of cocaine (10 or 15 mg/kg). Acute administration of cocaine increased the locomotor activity of mice. In animals treated repeatedly with the higher dose of cocaine, the locomotor hyperactivity induced by a challenge dose of the psychostimulant (15 mg/kg) was ca. twice as high as that after its first administration; in consequence, evidence for behavioral sensitization was obtained. Immune functions were evaluated by measuring the ability of splenocytes to proliferate and to produce cytokines such as interferon-gamma (IFN-gamma), interleukin (IL)-4 and IL-10. Acute cocaine administration significantly decreased proliferation of splenocytes to concanavalin A (Con A) and increased their ability to produce IFN-gamma. Repeated intermittent treatment with cocaine in a dose of 10 mg/kg significantly decreased the thymus weight and the proliferative response of T cells to a suboptimal dose of Con A. Sensitization with the higher dose of cocaine significantly enhanced IFN-gamma production. These data indicate that cocaine sensitization results in the development of a tolerant state to the cocaine-induced suppression of a thymus dependent T-lymphocyte response. It may be suggested that the cocaine sensitization partly depends on the altered balance of cytokine production, e.g. an increase in IFN-gamma production. Since repeated, intermittent use of cocaine by humans leads to psychoses or craving for this drug, our findings also seem to indicate considerable importance of monitoring and correcting immune changes in the therapy of cocaine addiction.

Cocaine increases inducible nitric oxide synthase expression in rats: effects of acute and binge administration

The present studies assessed the effects of acute and binge cocaine administration on the in vivo production of inducible nitric oxide synthase in a rat model of endotoxemia. Inducible nitric oxide synthase is a key enzyme involved in host defense and inflammatory responses consequent to infection through its production of nitric oxide. Male Lewis rats received subcutaneous injections of saline or selected doses of cocaine (7.5-30 mg/kg) at the same time as a 50 microg/kg dose of lipopolysaccharide (LPS). Animals in the binge cocaine experiments received two additional injections of cocaine or saline at 2 and 4 h after the initial injections. All animals were sacrificed 6 h after initial drug administration and tissues harvested for determination of iNOS protein levels. Plasma nitrite/nitrate levels were also assayed to assess any treatment-related differences in the degradative by-products of nitric oxide metabolism. Western blot analyses of iNOS expression indicated that both acute and binge cocaine treatment resulted in significant increases in iNOS expression in all tissues assayed. Furthermore, acute and binge cocaine treatment also dose-dependently increased plasma nitrite levels. These data suggest that cocaine may impact resistance to gram-negative infections and severity of these infections via modulation of nitric oxide parameters.

Cocaine causes increased type I interferon secretion by both L929 cells and murine macrophages

Cocaine has been demonstrated to have a number of different effects on immune cell functions. We have reported alterations of cellular functions by macrophages (Mphi) exposed to cocaine in vitro, including the inhibition of mouse hepatitis virus replication. Here, we present evidence that cocaine stimulates the secretion of an antiviral product that is neutralized by anti-interferon (anti-IFN). A dose-dependent increase in the secretion of IFN by both Mphi and L929 cells incubated with cocaine, with a concomitant decrease in virus replication, is also reported. The increase in IFN secretion was most pronounced when cells were cultured in the presence of the IFN inducer poly(I.C). The effect of cocaine on IFN production was found to be primarily at the transcript level in both Mphi and L929 cells. These findings further support our previous research demonstrating an antiviral activity of cocaine in vitro. The relevance of this activity to viral infections in general remains to be determined.

Cocaine enhances brain endothelial adhesion molecules and leukocyte migration

Leukocyte infiltration of cerebral vessels in cocaine-associated vasculopathy suggests that cocaine may enhance leukocyte migration. We have investigated cocaine's effects on leukocyte adhesion in human brain microvascular endothelial cell (BMVEC) cultures and monocyte migration in an in vitro blood-brain barrier (BBB) model constructed with BMVEC and astrocytes. Cocaine (10(-5) to 10(-9) M) enhanced adhesion of monocytes and neutrophils to BMVEC. In the BBB model, cocaine (10(-4) to 10(-8) M) enhanced monocyte transmigration. Cocaine increased expression of endothelial adhesion molecules, intercellular adhesion molecule-1 (ICAM-1, CD54), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leukocyte adhesion molecule-1 (ELAM-1) on BMVEC. The peak effect on ICAM-1 expression was between 6 and 18 h after treatment. ICAM-1 was increased by cocaine in BMVEC, but not in human umbilical vein endothelial cells, and the enhancement was greater in a coculture of BMVEC with monocytes. ICAM-1 expression was enhanced by a transcriptional mechanism. Polymyxin B inhibited up-regulation of adhesion molecules by LPS but not by cocaine. In LPS-activated BMVEC/monocyte coculture, cocaine increased secretion of tumor necrosis factor-alpha and interleukin-6. Taken together, these findings indicate that cocaine enhances leukocyte migration across the cerebral vessel wall, in particular under inflammatory conditions, but the effects are variable in different individuals. Cocaine's effects are exerted through a cascade of augmented expression of inflammatory cytokines and endothelial adhesion molecules. These could underlie the cerebrovascular complications of cocaine abuse.