The relationship of CSF and plasma cytokine levels in HIV infected patients with neurocognitive impairment

CD8+T cells and monocytes were associated with brain alterations in human immunodeficiency virus-infected individuals with cognitive impairment

Cognitive impairment (CI) continues to be a concern for people living with HIV-1 (PLWH) in the era of antiretroviral therapy (ART), yet the underlying mechanisms remain unclear. We aimed to elucidate the structural and functional brain alterations and peripheral immune profile of PLWH with CI, as well as the correlation between them. PLWH were divided into CI (n = 30) and cognitive normal (CN, n = 59) groups based on the Montreal Cognitive Assessment, and underwent multi-modal magnetic resonance imaging. Mass cytometry was utilized to profile immune cells, while the liquid chip technique was employed to measure plasma levels of cytokines and chemokines. Spearman correlation analyses were conducted for correlation analysis. Here, we found that the gray matter volume in left supramarginal gyrus was reduced, and the ReHo in the right middle frontal gyrus and the functional connectivity between right middle frontal gyrus and left postcentral gyrus were enhanced in CI group compared to CN group. Additionally, the frequencies of naïve CD8+T cells (Tn) and CD31lowCD8+ Tn were significantly correlated with gray matter volume in the left supramarginal gyrus. The amplitude of low frequency fluctuations in a specific brain region of frontal-middle lobe was negatively correlated with the frequencies of non-classical monocytes (nCM) and their subpopulations (CCR2lownCM, CD57lownCM and CD127+nCM), and positively associated with the plasma interleukin 25 and transforming growth factor-α levels. These findings suggest the association between peripheral immunity and the brain abnormalities in PLWH, highlighting a potential role of the immune-brain-cognition axis in the pathogenesis of CI in Chinese PLWH.

Multimodal Approach to Neurocognitive Function in People Living with HIV in the cART Era: A Comprehensive Review

Combination antiretroviral treatment (cART) has revolutionized the management of human immunodeficiency virus (HIV) and has markedly improved the disease burden and life expectancy of people living with HIV. HIV enters the central nervous system (CNS) early in the course of infection, establishes latency, and produces a pro-inflammatory milieu that may affect cognitive functions, even in the cART era. Whereas severe forms of neurocognitive impairment (NCI) such as HIV-associated dementia have declined over the last decades, milder forms have become more prevalent, are commonly multifactorial, and are associated with comorbidity burdens, mental health, cART neurotoxicity, and ageing. Since 2007, the Frascati criteria have been used to characterize and classify HIV-associated neurocognitive disorders (HAND) into three stages, namely asymptomatic neurocognitive impairment (ANI), mild neurocognitive disorder (MND), and HIV-associated dementia (HAD). These criteria are based on a comprehensive neuropsychological assessment that presupposes the availability of validated, demographically adjusted, and normative population data. Novel neuroimaging modalities and biomarkers have been proposed in order to complement NCI assessments, elucidate neuropathogenic mechanisms, and support HIV-associated NCI diagnosis, monitoring, and prognosis. By integrating neuropsychological assessments with biomarkers and neuroimaging into a holistic care approach, clinicians can enhance diagnostic accuracy, prognosis, and patient outcomes. This review interrogates the value of these modes of assessment and proposes a unified approach to NCI diagnosis.

Differential regulation of microglial states by colony stimulating factors

Recent studies have emphasized the role of microglia in the progression of many neurodegenerative diseases. The colony stimulating factors, CSF-1 (M-CSF), granulocyte-macrophage CSF (GM-CSF) and granulocyte CSF (G-CSF) regulate microglia through different cognate receptors. While the receptors for GM-CSF (GM-CSFR) and G-CSF (G-CSFR) are specific for their ligands, CSF-1 shares its receptor, the CSF-1 receptor-tyrosine kinase (CSF-1R), with interleukin-34 (IL-34). All four cytokines are expressed locally in the CNS. Activation of the CSF-1R in macrophages is anti-inflammatory. In contrast, the actions of GM-CSF and G-CSF elicit different activated states. We here review the roles of each of these cytokines in the CNS and how they contribute to the development of disease in a mouse model of CSF-1R-related leukodystrophy. Understanding their roles in this model may illuminate their contribution to the development or exacerbation of other neurodegenerative diseases.

The Impact of COVID-19 on People Living with HIV-1 and HIV-1-Associated Neurological Complications

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the causative pathogen of the coronavirus disease 2019 (COVID-19) pandemic, a fatal respiratory illness. The associated risk factors for COVID-19 are old age and medical comorbidities. In the current combined antiretroviral therapy (cART) era, a significant portion of people living with HIV-1 (PLWH) with controlled viremia is older and with comorbidities, making these people vulnerable to SARS-CoV-2 infection and COVID-19-associated severe outcomes. Additionally, SARS-CoV-2 is neurotropic and causes neurological complications, resulting in a health burden and an adverse impact on PLWH and exacerbating HIV-1-associated neurocognitive disorder (HAND). The impact of SARS-CoV-2 infection and COVID-19 severity on neuroinflammation, the development of HAND and preexisting HAND is poorly explored. In the present review, we compiled the current knowledge of differences and similarities between SARS-CoV-2 and HIV-1, the conditions of the SARS-CoV-2/COVID-19 and HIV-1/AIDS syndemic and their impact on the central nervous system (CNS). Risk factors of COVID-19 on PLWH and neurological manifestations, inflammatory mechanisms leading to the neurological syndrome, the development of HAND, and its influence on preexisting HAND are also discussed. Finally, we have reviewed the challenges of the present syndemic on the world population, with a particular emphasis on PLWH.

IRAK1 inhibition blocks the HIV-1 RNA mediated pro-inflammatory cytokine response from microglia

Human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) are a common source of morbidity in people living with HIV (PLWH). Although antiretroviral therapy (ART) has lessened the severity of neurocognitive disorders, cognitive impairment still occurs in PLWH receiving ART. The pathogenesis of HAND is likely multifaceted, but common factors include the persistence of HIV transcription within the central nervous system, higher levels of pro-inflammatory cytokines in the cerebrospinal fluid, and the presence of activated microglia. Toll-like receptor (TLR) 7 and TLR8 are innate pathogen recognition receptors located in microglia and other immune and non-immune cells that can recognise HIV RNA and trigger pro-inflammatory responses. IL-1 receptor-associated kinase (IRAK) 1 is key to these signalling pathways. Here, we show that IRAK1 inhibition inhibits the TLR7 and TLR8-dependent pro-inflammatory response to HIV RNA. Using genetic and pharmacological inhibition, we demonstrate that inhibition of IRAK1 prevents IRAK1 phosphorylation and ubiquitination, and the subsequent recruitment of TRAF6 and the TAK1 complex to IRAK1, resulting in the inhibition of downstream signalling and the suppression of pro-inflammatory cytokine and chemokine release.

The association between inflammatory markers in blood and cerebrospinal fluid: a systematic review and meta-analysis

BACKGROUND

Neuroinflammatory processes have been hypothesized to play a role in the pathogenesis of psychiatric and neurological diseases. Studies on this topic often rely on analysis of inflammatory biomarkers in peripheral blood. Unfortunately, the extent to which these peripheral markers reflect inflammatory processes in the central nervous system (CNS) is unclear.

METHODS

We performed a systematic review and found 29 studies examining the association between inflammatory marker levels in blood and cerebrospinal (CSF) samples. We performed a random effects meta-analysis of 21 studies (pooled n = 1679 paired samples) that reported the correlation of inflammatory markers in paired blood-CSF samples.

RESULTS

A qualitative review revealed moderate to high quality of included studies with the majority of studies reporting no significant correlation of inflammatory markers between paired blood-CSF. Meta-analyses revealed a significant low pooled correlation between peripheral and CSF biomarkers (r = 0.21). Meta-analyses of individual cytokines revealed a significant pooled correlation for IL-6 (r = 0.26) and TNFα (r = 0.3) after excluding outlier studies, but not for other cytokines. Sensitivity analyses showed that correlations were highest among participants with a median age above 50 (r = 0.46) and among autoimmune disorder patients (r = 0.35).

CONCLUSION

This systematic review and meta-analysis revealed poor correlation between peripheral and central inflammatory markers in paired blood-CSF samples, with increased correlations in certain study populations. Based on the current findings, peripheral inflammatory markers are a poor reflection of the neuroinflammatory profile.

The Role of Pannexin-1 Channels in HIV and NeuroHIV Pathogenesis

The human immunodeficiency virus-1 (HIV) enters the brain shortly after infection, leading to long-term neurological complications in half of the HIV-infected population, even in the current anti-retroviral therapy (ART) era. Despite decades of research, no biomarkers can objectively measure and, more importantly, predict the onset of HIV-associated neurocognitive disorders. Several biomarkers have been proposed; however, most of them only reflect late events of neuronal damage. Our laboratory recently identified that ATP and PGE2, inflammatory molecules released through Pannexin-1 channels, are elevated in the serum of HIV-infected individuals compared to uninfected individuals and other inflammatory diseases. More importantly, high circulating ATP levels, but not PGE2, can predict a decline in cognition, suggesting that HIV-infected individuals have impaired ATP metabolism and associated signaling. We identified that Pannexin-1 channel opening contributes to the high serological ATP levels, and ATP in the circulation could be used as a biomarker of HIV-associated cognitive impairment. In addition, we believe that ATP is a major contributor to chronic inflammation in the HIV-infected population, even in the anti-retroviral era. Here, we discuss the mechanisms associated with Pannexin-1 channel opening within the circulation, as well as within the resident viral reservoirs, ATP dysregulation, and cognitive disease observed in the HIV-infected population.

Colony stimulating factors in the nervous system

Although traditionally seen as regulators of hematopoiesis, colony-stimulating factors (CSFs) have emerged as important players in the nervous system, both in health and disease. This review summarizes the cellular sources, patterns of expression and physiological roles of the macrophage (CSF-1, IL-34), granulocyte-macrophage (GM-CSF) and granulocyte (G-CSF) colony stimulating factors within the nervous system, with a particular focus on their actions on microglia. CSF-1 and IL-34, via the CSF-1R, are required for the development, proliferation and maintenance of essentially all CNS microglia in a temporal and regional specific manner. In contrast, in steady state, GM-CSF and G-CSF are mainly involved in regulation of microglial function. The alterations in expression of these growth factors and their receptors, that have been reported in several neurological diseases, are described and the outcomes of their therapeutic targeting in mouse models and humans are discussed.

HIV Tat-Mediated Induction of Monocyte Transmigration Across the Blood-Brain Barrier: Role of Chemokine Receptor CXCR3

HIV trans-activator of transcription (Tat), one of the cytotoxic proteins secreted from HIV-infected cells, is also known to facilitate chemokine-mediated transmigration of monocytes into the brain leading, in turn, to neuroinflammation and thereby contributing to the development of HIV-associated neurocognitive disorders (HAND). The mechanism(s) underlying HIV Tat-mediated enhancement of monocyte transmigration, however, remain largely unknown. CXC chemokine receptor 3 (CXCR3) that is expressed by the peripheral monocytes is known to play a role in the monocyte influx and accumulation. In the present study, we demonstrate for the first time that exposure of human monocytes to HIV Tat protein resulted in upregulated expression of CXCR3 leading, in turn, to increased monocyte transmigration across the blood–brain barrier (BBB) both in the in vitro and in vivo model systems. This process involved activation of toll-like receptor 4 (TLR4), with downstream phosphorylation and activation of TANK-binding kinase 1 (TBK1), and subsequent phosphorylation and nuclear translocation of interferon regulatory factor 3 (IRF3), ultimately leading to enhanced expression of CXCR3 in human monocytes. These findings imply a novel molecular mechanism underlying HIV Tat-mediated increase of monocyte transmigration across the BBB, while also implicating a novel role of CXCR3-dependent monocyte transmigration in HIV Tat-mediated neuroinflammation.

Insult to Injury-Potential Contribution of Coronavirus Disease-19 to Neuroinflammation and the Development of HIV-Associated Neurocognitive Disorders

Severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2 is responsible for a new coronavirus disease known as coronavirus disease-19 (COVID-19). SARS-CoV-2 reports neurotropic properties and may have neurological implications, and this creates another health burden for people living with HIV. As yet, the impact of COVID-19 on (neuro)inflammation and the development of HIV-associated neurocognitive disorders (HAND) is not fully known. Here, we reviewed preliminary evidence that provides clues that COVID-19 may exacerbate inflammatory mechanisms related to the development of HAND.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Chemokines in Prediabetes and Type 2 Diabetes: A Meta-Analysis

Background

A growing number of studies found inconsistent results on the role of chemokines in the progression of type 2 diabetes (T2DM) and prediabetes (PDM). The purpose of this meta-analysis was to summarize the results of previous studies on the association between the chemokines system and T2DM/PDM.

Methods

We searched in the databases, PubMed, Web of Science, Embase and Cochrane Library, for eligible studies published not later than March 1, 2020. Data extraction was performed independently by 2 reviewers, on a standardized, prepiloted form. Group differences in chemokines concentrations were summarized using the standardized mean difference (SMD) with a 95% confidence interval (CI), calculated by performing a meta-analysis using the random-effects model.

Results

We identified 98 relevant studies that investigated the association between 32 different chemokines and T2DM/PDM. Altogether, these studies involved 14,708 patients and 14,574 controls. Results showed that the concentrations of CCL1, CCL2, CCL4, CCL5, CCL11, CXCL8, CXCL10 and CX3CL1 in the T2DM patients were significantly higher than that in the controls, while no difference in these concentrations was found between the PDM patients and controls.

Conclusion

Progression of T2DM may be associated with elevated concentrations of chemokines.

Meta-Analysis Registration

PROSPERO, identifier CRD42019148305.

Sex-specific associations between cerebrospinal fluid inflammatory marker levels and cognitive function in antiretroviral treated people living with HIV in rural Uganda

People with HIV (PWH) taking antiretroviral therapy (ART) have persistent cognitive impairment. The prevalence of cognitive impairment is higher in women with HIV (WWH) compared to men with HIV (MWH), possibly due to sex differences in immune function. Here we report sex differences in cerebrospinal fluid (CSF) immune markers in relation to cognitive performance. A subset of 83 PWH on ART (52% WWH; mean age = 37.6 years, SD = 7.9) from the Rakai community cohort study Cohort and Rakai Health Sciences Program supported clinics in rural Uganda completed a neuropsychological (NP) assessment and a lumbar puncture. CSF was used to measure 16 cytokines/chemokines. Individual NP test z-scores were generated based on local normative data. A series of least absolute shrinkage and selection operator (lasso) regressions examined associations between CSF inflammatory markers and NP outcomes. Overall, there were no sex differences in CSF inflammatory marker levels. However, MWH displayed more associations between inflammatory markers and cognitive performance than WWH. Among MWH, inflammatory markers were associated with a number of cognitive domains, including attention, processing speed, fluency, executive function, learning and memory. MIP-1β, INF-γ, GM-CSF, IL-7 and IL-12p70 were associated with multiple domains. Among WWH, few inflammatory markers were associated cognition. Degree of associations between CSF inflammatory biomarkers and cognitive performance varied by sex in this young, ART-treated, Ugandan cohort. Further investigation into sex-specific inflammatory mechanisms of cognitive impairment among PWH is warranted to inform sex-specific management strategies.

Persistent COVID-19-associated neurocognitive symptoms in non-hospitalized patients

As cases of coronavirus disease 2019 (COVID-19) mount worldwide, attention is needed on potential long-term neurologic impacts for the majority of patients who experience mild to moderate illness managed as outpatients. To date, there has not been discussion of persistent neurocognitive deficits in patients with milder COVID-19. We present two cases of non-hospitalized patients recovering from COVID-19 with persistent neurocognitive symptoms. Commonly used cognitive screens were normal, while more detailed testing revealed working memory and executive functioning deficits. An observational cohort study of individuals recovering from COVID-19 (14 or more days following symptom onset) identified that among the first 100 individuals enrolled, 14 were non-hospitalized patients reporting persistent cognitive issues. These 14 participants had a median age of 39 years (interquartile range: 35-56), and cognitive symptoms were present for at least a median of 98 days (interquartile range: 71-120 following acute COVID-19 symptoms); no participants with follow-up evaluation reported symptom resolution. We discuss potential mechanisms to be explored in future studies, including direct viral effects, indirect consequences of immune activation, and immune dysregulation causing auto-antibody production.

Chronic inflammation mediates brain injury in HIV infection: relevance for cure strategies

PURPOSE OF REVIEW

Chronic inflammation is a major component of HIV infection, the effects of which can be devastating in the central nervous system (CNS). Protecting the brain is, therefore, critical as efforts proceed to cure HIV infection by reactivating latent viral reservoirs and driving immune responses. We review the clinical presentation and pathology findings of inflammatory processes in the CNS in patients managed with ART and the drivers of these processes.

RECENT FINDINGS

Chronic inflammation is associated with increased mortality and morbidity and HIV infection increases the risk for chronic diseases, especially cognitive impairment. Latent viral reservoirs, including microglia and tissue macrophages, contribute to inflammation in the CNS. Inflammation is generated and maintained through residual viral replication, dysregulation of infected cells, continuously produced viral proteins and positive feedback loops of chronic inflammation. Novel therapeutics and lifestyle changes may help to protect the CNS from immune-mediated damage.

SUMMARY

As therapies are developed to cure HIV, it is important to protect the CNS from additional immune-mediated damage. Adjunctive therapies to restore glial function, reduce neuroinflammation and systemic inflammation, and inhibit expression of viral proteins are needed.

Targeting Cannabinoid Receptor 2 on Peripheral Leukocytes to Attenuate Inflammatory Mechanisms Implicated in HIV-Associated Neurocognitive Disorder

HIV infection affects an estimated 38 million people. Approximately 50% of HIV patients exhibit neurocognitive dysfunction termed HIV-Associated Neurocognitive Disorder (HAND). HAND is a consequence of chronic low-level neuroinflammation due to HIV entry into the brain. Initially, monocytes become activated in circulation and traffic to the brain. Monocytes, when activated, become susceptible to infection by HIV and can then carry the virus across the blood brain barrier. Once in the brain, activated monocytes secrete chemokines, which recruit virus-specific CD8+ T cells into the brain to further promote neuroinflammation. HAND is closely linked to systemic inflammation driven, in part, by HIV but is also due to persistent translocation of microorganisms across the GI tract. Persistent anti-viral responses in the GI tract compromise microbial barrier integrity. Indeed, HIV patients can exhibit remarkably high levels of activated (CD16+) monocytes in circulation. Recent studies, including our own, show that HIV patients using medical marijuana exhibit lower levels of circulating CD16+ monocytes than non-cannabis using HIV patients. Cannabis is a known immune modulator, including anti-inflammatory properties, mediated, in part, by ∆9-tetrahydrocannabinol (THC), as well as less characterized minor cannabinoids, such as cannabidiol (CBD), terpenes and presumably other cannabis constituents. The immune modulating activity of THC is largely mediated through cannabinoid receptors (CB) 1 and 2, with CB1 also responsible for the psychotropic properties of cannabis. Here we discuss the anti-inflammatory properties of cannabinoids in the context of HIV and propose CB2 as a putative therapeutic target for the treatment of neuroinflammation. Graphical Abstract HIV-associated neurocognitive disorder is a systemic inflammatory disease leading to activation of plasmacytoid dendritic cells, monocytes and T cells. Monocyte and CD8 T cell migration across the BBB and interaction with astrocytes promotes neurotoxic inflammatory mediators release. CB2 ligands are proposed as therapeutics capable of suppressing systemic and localized inflammation.

Cognition, Structural Brain Changes, and Systemic Inflammation in Adolescents Living With HIV on Antiretroviral Therapy

OBJECTIVE

To investigate the association between neurocognitive impairment, neuroimaging, and systemic inflammation in perinatally infected adolescents living with HIV (PHIV) on antiretroviral therapy (ART). Systemic inflammation may be one mechanism driving neurocognitive impairment despite ART, but this has not been investigated in adolescence when the brain is undergoing rapid development.

SETTING

Cape Town, South Africa.

METHODS

Baseline data were drawn from the Cape Town Adolescent Antiretroviral Cohort. PHIV on ART >6 months completed a comprehensive neurocognitive test battery. Diffusion tensor imaging and structural brain magnetic resonance imaging was done to determine whole brain fractional anisotropy, mean diffusion (MD), grey and white matter volumes, and cortical thickness. We examined how neurocognitive and neurostructural measures were associated with a concurrently measured marker of systemic inflammation, high-sensitive C-reactive protein (hs-CRP).

RESULTS

One hundred sixty-eight PHIV ages 9-12 years (mean CD4 980 cells/µL; 85.3% viral load <50 copies/mL) and 43 controls were included in the analysis. PHIV had similar hs-CRP (P = 0.17) to controls, after participants with hs-CRP >10 were excluded from the analysis. Forty-eight percent of the PHIV in this analysis have a neurocognitive disorder. Whole brain grey (P = 0.049) and white matter volumes (P = 0.044) were lowest in PHIV with a major neurocognitive disorder. Higher MD, was found in PHIV with a major neurocognitive disorder (P = 0.002). Among PHIV with a neurocognitive disorder, hs-CRP negatively correlated with general intelligence, visual spatial acuity, and executive function (all P = < 0.05). Whole brain MD correlated with higher hs-CRP values (P = < 0.01) in PHIV.

CONCLUSIONS

A marker of systemic inflammation was associated with both neurocognitive impairment and MD increases in PHIV.

Increased IL-8 levels in HIV-infected individuals who initiated ART with CD4+ T cell counts <350 cells/mm3 - A potential hallmark of chronic inflammation

The identification of inflammatory markers in HIV+ individuals on ART is fundamental since chronic ART-controlled HIV infection is linked to an increased inflammatory state. In this context, we assessed plasma levels of pro-inflammatory cytokines (IL-1β, IL-8, and IL-12p70) of HIV+ individuals who initiated ART after immunosuppression (CD4+ T cell counts <350 cells/mm3). HIV+ individuals were stratified according to two extreme phenotypes: Slow Progressors (SPs; individuals with at least 8 years of infection before ART initiation) and Rapid Progressors (RPs; individuals who needed to initiate ART within 1-4 years after infection). A control group was composed of HIV-uninfected individuals. We found increased IL-8 levels (median: 5.13 pg/mL; SPs and RPs together) in HIV-infected individuals on ART as compared to controls (median: 3.2 pg/mL; p = 0.04), although no association with the progression profile (slow or rapid progressors) or CD4+ T cell counts at sampling was observed. This result indicates that IL-8 is a general marker of chronic inflammation in HIV+ individuals on ART, independently of CD4+ T cell counts at the beginning of the treatment or of the potential progression profile of the patient. In this sense, IL-8 may be considered a possible target for novel therapies focused on reducing inflammation in chronic HIV infection.

Peripheral immune dysregulation in the ART era of HIV-associated neurocognitive impairments: A systematic review

Human immunodeficiency virus-associated neurocognitive impairment (HANI) remains problematic despite the effective use of antiretroviral therapy (ART) and viral suppression. A dysregulated immune response contributes to the development of HANI but findings on the association between peripheral blood immune markers and HANI have been inconsistent. We therefore conducted a systematic review of studies of the association of peripheral blood immune markers with neurocognitive performance in ART experienced HIV-positive participants. Thirty-seven studies were eligible, including 12 longitudinal studies and 25 cross-sectional studies. Findings consistently show that HIV-positive participants have altered immune marker levels, including elevated markers of monocyte activation (neopterin, sCD14, sCD163) and inflammation (CCL2, IL-8, IL-18, IP-10, IFN-α, sTNFR-II and TNF-α). These elevated levels persist in HIV-positive participants despite ART. The majority of studies found associations of HANI with immune markers, including those linked to monocyte activation (sCD14 and sCD163) and inflammation (IL-18 and IP-10). Despite the heterogeneity of studies reviewed, due to the presence of raised peripheral markers, our narrative review provides evidence of chronic inflammation despite ART. The raised levels of these markers may suggest certain mechanisms are active, potentially those involved in the neuropathophysiology of HANI.

Plasma CXCL10 correlates with HAND in HIV-infected women

HIV-associated neurocognitive disorder (HAND) is characterized by chronic immune activation. We aimed to identify biomarkers associated with HAND and to investigate their association with cognitive function and sex, in a homogenous cohort of HIV-infected (HIV+) young adults, parenterally infected during early childhood. One hundred forty-four HIV+ Romanian participants (51% women) without major confounders underwent standardized neurocognitive and medical evaluation in a cross-sectional study. IFN-γ, IL-1β, IL-6, CCL2, CXCL8, CXCL10, and TNF-α were measured in plasma in all participants and in cerebrospinal fluid (CSF) in a subgroup of 56 study participants. Biomarkers were compared with neurocognitive outcomes, and the influence of sex and HIV disease biomarkers was assessed. In this cohort of young adults (median age of 24 years), the rate of neurocognitive impairment (NCI) was 36.1%. Median current CD4+ count was 479 cells/mm3 and 36.8% had detectable plasma viral load. Women had better HIV-associated overall status. In plasma, controlling for sex, higher levels of IL-6 and TNF-α were associated with NCI (p < 0.05). Plasma CXCL10 showed a significant interaction with sex (p = 0.02); higher values were associated with NCI in women only (p = 0.02). Individuals with undetectable viral load had significantly lower plasma CXCL10 (p < 0.001) and CCL2 (p = 0.02) levels, and CSF CXCL10 (p = 0.01), IL-6 (p = 0.04), and TNF-α (p = 0.04) levels. NCI in young men and women living with HIV was associated with higher IL-6 and TNF-α in plasma, but not in the CSF. CXCL10 was identified as a biomarker of NCI specifically in women with chronic HIV infection.

The impact of substance abuse on HIV-mediated neuropathogenesis in the current ART era

Approximately 37 million people worldwide are infected with human immunodeficiency virus (HIV). One highly significant complication of HIV infection is the development of HIV-associated neurocognitive disorders (HAND) in 15-55% of people living with HIV (PLWH), that persists even in the antiretroviral therapy (ART) era. The entry of HIV into the central nervous system (CNS) occurs within 4-8 days after peripheral infection. This establishes viral reservoirs that may persist even in the presence of ART. Once in the CNS, HIV infects resident macrophages, microglia, and at low levels, astrocytes. In response to chronic infection and cell activation within the CNS, viral proteins, inflammatory mediators, and host and viral neurotoxic factors produced over extended periods of time result in neuronal injury and loss, cognitive deficits and HAND. Substance abuse is a common comorbidity in PLWH and has been shown to increase neuroinflammation and cognitive disorders. Additionally, it has been associated with poor ART adherence, and increased viral load in the cerebrospinal fluid (CSF), that may also contribute to increased neuroinflammation and neuronal injury. Studies have examined mechanisms that contribute to neuroinflammation and neuronal damage in PLWH, and how substances of abuse exacerbate these effects. This review will focus on how substances of abuse, with an emphasis on methamphetamine (meth), cocaine, and opioids, impact blood brain barrier (BBB) integrity and transmigration of HIV-infected and uninfected monocytes across the BBB, as well as their effects on monocytes/macrophages, microglia, and astrocytes within the CNS. We will also address how these substances of abuse may contribute to HIV-mediated neuropathogenesis in the context of suppressive ART. Additionally, we will review the effects of extracellular dopamine, a neurotransmitter that is increased in the CNS by substances of abuse, on HIV neuropathogenesis and how this may contribute to neuroinflammation, neuronal insult, and HAND in PLWH with active substance use. Lastly, we will discuss some potential therapies to limit CNS inflammation and damage in HIV-infected substance abusers.

Δ9-Tetrahydrocannabinol Suppresses Monocyte-Mediated Astrocyte Production of Monocyte Chemoattractant Protein 1 and Interleukin-6 in a Toll-Like Receptor 7-Stimulated Human Coculture

Cannabis is widely used in the United States, with an estimated prevalence of 9.5%. Certain cannabinoids in Cannabis sativa, Δ9-tetrahydrocannabinol (THC) in particular, possess immune-modulating and anti-inflammatory activity. Depending on the context, the anti-inflammatory activity of cannabinoids may be beneficial (e.g., in treating inflammatory diseases) or detrimental to normal immune defense against pathogens. The potential beneficial effect of cannabinoids on chronic neuroinflammation has gained recent attention. Monocyte migration to the brain has been implicated as a key event in chronic neuroinflammation and in the etiology of central nervous system diseases including viral infection (e.g., human immunodeficiency virus-associated neurocognitive disorder). In the brain, monocytes can contribute to neuroinflammation through interactions with astrocytes, including inducing astrocyte secretion of cytokines and chemokines. In a human coculture system, monocyte-derived interleukin (IL)-1β due to Toll-like receptor 7 (TLR7) activation has been identified to promote astrocyte production of monocyte chemoattractant protein (MCP)-1 and IL-6. THC treatment of the TLR7-stimulated coculture suppressed monocyte secretion of IL-1β, resulting in decreased astrocyte production of MCP-1 and IL-6. Furthermore, THC displayed direct inhibition of monocytes, as TLR7-stimulated monocyte monocultures treated with THC also showed suppressed IL-1β production. The cannabinoid receptor 2 (CB2) agonist, JWH-015, impaired monocyte IL-1β production similar to that of THC, suggesting that THC acts, in part, through CB2. THC also suppressed key elements of the IL-1β production pathway, including IL1B mRNA levels and caspase-1 activity. Collectively, this study demonstrates that the anti-inflammatory properties of THC suppress TLR7-induced monocyte secretion of IL-1β through CB2, which results in decreased astrocyte secretion of MCP-1 and IL-6. SIGNIFICANCE STATEMENT: Because cannabis use is highly prevalent in the United States and has putative anti-inflammatory properties, it is important to investigate the effect of cannabinoids on immune cell function. Furthermore, cannabinoids have garnered particular interest due to their potential beneficial effects on attenuating viral-induced chronic neuroinflammation. This study utilized a primary human coculture system to demonstrate that the major psychotropic cannabinoid in cannabis, Δ9-tetrahydrocannabinol, and a cannabinoid receptor-2 selective agonist suppress specific monocyte-mediated astrocyte inflammatory responses.

The Association of Immune Markers with Cognitive Performance in South African HIV-Positive Patients

Dysregulated expression of neuro-immune markers has previously been linked to HIV-associated neurocognitive impairment. We undertook an exploratory approach in a HIV clade-C cohort, investigating the association between eight immune markers and neurocognitive performance in 99 HIV+ and 51 HIV- participants. Markers were selected on preliminary and putative evidence of their link to key neuro-immune functions. Cognitive performance was established using a battery of tests sensitive to HIV-associated neurocognitive impairment, with domain-based scores utilized in analysis. The markers Thymidine phosphorylase (TYMP) and Neutrophil gelatinase-associated lipocalin (NGAL) were significantly higher while Matrix Metalloproteinase (MMP)9 was significantly lower in HIV+ participants. Our results further showed that in the HIV+ group, worse psychomotor processing speed was associated with higher TYMP and NGAL levels and worse motor function was associated with higher NGAL levels. Future studies should explore the underlying mechanisms of these markers in HIV-associated neurocognitive impairment. Graphical Abstract The association of peripheral immune markers with neurocognitive performance in South African HIV-positive patients.

HIV-Associated Neurocognitive Impairment in the Modern ART Era: Are We Close to Discovering Reliable Biomarkers in the Setting of Virological Suppression?

The prevalence of the most severe forms of HIV-associated neurocognitive disorders (HAND) is decreasing due to worldwide availability and high efficacy of antiretroviral treatment (ART). However, several grades of HIV-related cognitive impairment persist with effective ART and remain a clinical concern for people with HIV (PWH). The pathogenesis of these cognitive impairments has yet to be fully understood and probably multifactorial. In PWH with undetectable peripheral HIV-RNA, the presence of viral escapes in cerebrospinal fluid (CSF) might explain a proportion of cases, but not all. Many other mechanisms have been hypothesized to be involved in disease progression, in order to identify possible therapeutic targets. As potential indicators of disease staging and progression, numerous biomarkers have been used to characterize and implicate chronic inflammation in the pathogenesis of neuronal injuries, such as certain phenotypes of activated monocytes/macrophages, in the context of persistent immune activation. Despite none of them being disease-specific, the correlation of several CSF cellular biomarkers to HIV-induced neuronal damage has been investigated. Furthermore, recent studies have been evaluating specific microRNA (miRNA) profiles in the CSF of PWH with neurocognitive impairment (NCI). The aim of the present study is to review the body of evidence on different biomarkers use in research and clinical settings, focusing on PWH on ART with undetectable plasma HIV-RNA.

Peroxisome Proliferator-Activated Receptor-gamma agonists exhibit anti-inflammatory and antiviral effects in an EcoHIV mouse model

The widespread use of combination antiretroviral therapy (cART) has resulted in significantly reduced deaths from HIV-1 associated complications and opportunistic infections. However, it is estimated that up to 50% of HIV-1 infected individuals still develop HIV-1 associated neurocognitive disorders (HAND). With no treatment currently available for patients, there is a critical need to identify therapeutic approaches that can treat this disorder. Evidence suggests that targeting Peroxisome Proliferator-Activated Receptor-gamma (PPARγ) can be anti-inflammatory in neurological disorders. Here we show that treatment with PPARγ agonists (rosiglitazone or pioglitazone) in primary cultures of mouse glial cells reversed EcoHIV-induced inflammatory genes (TNFα, IL-1β, CCL2, CCL3, CXCL10) and indicator of oxidative stress (iNOS). Furthermore, in vivo, mice administered with EcoHIV through intracranial injection resulted in upregulation of inflammatory genes (TNFα, IL-1β, IFNγ, CCL2, CCL3, CXCL10) and oxidative stress marker (iNOS) in the brain which was reversed through intraperitoneal administration of PPARγ agonists (rosiglitazone or pioglitazone). Finally, we demonstrated that treatment with these compounds in vivo reduced EcoHIV p24 protein burden in the brain. Our results suggest that treatment with PPARγ agonists are anti-inflammatory and antiviral in an in vivo model of EcoHIV infection. These drugs hold promise as potential candidates for HAND treatment in the future.

Linked CSF reduction of phosphorylated tau and IL-8 in HIV associated neurocognitive disorder

HIV-associated neurocognitive disorder (HAND) is a common condition in both developed and developing nations, but its cause is largely unknown. Previous research has inconsistently linked Alzheimer's disease (AD), viral burden, and inflammation to the onset of HAND in HIV-infected individuals. Here we simultaneously measured cerebrospinal fluid (CSF) levels of established amyloid and tau biomarkers for AD, viral copy numbers, and six key cytokines in 41 HIV-infected individuals off combination anti-retroviral therapy (14 with HAND) who underwent detailed clinical and neuropsychological characterization, and compared their CSF patterns with those from young healthy subjects, older healthy subjects with normal cognition, and older people with AD. HAND was associated with the lowest CSF levels of phosphorylated tau (p-Tau181) after accounting for age and race. We also found very high CSF levels of the pro-inflammatory interferon gamma-induced protein 10 (IP-10/CXCL10) in HIV regardless of cognition, but elevated CSF interleukin 8 (IL-8/CXCL8) only in HIV-NC but not HAND. Eleven HIV-infected subjects underwent repeat CSF collection six months later and showed strongly correlated longitudinal changes in p-Tau181 and IL-8 levels (R = 0.841). These data suggest reduced IL-8 relative to IP-10 and reduced p-Tau181 to characterize HAND.

Cerebrospinal fluid extracellular vesicles and neurofilament light protein as biomarkers of central nervous system injury in HIV-infected patients on antiretroviral therapy

Objective:

The relationship of cerebrospinal fluid (CSF) extracellular vesicles to neurocognitive impairment (NCI) in HIV-infected individuals is unclear. Here, we characterize CSF extracellular vesicles and their association with central nervous system (CNS) injury related biomarkers [neurofilament light (NFL), S100B, neopterin] and NCI in HIV-positive individuals on combination antiretroviral therapy (cART).

Design:

A cross-sectional and longitudinal study of CSF samples from HIV-positive individuals on cART.

Methods:

NFL, S100B and neopterin were measured by ELISA in 190 CSF samples from 112 individuals (67 HIV-positive and 45 HIV-negative). CSF extracellular vesicles were isolated and characterized by electron microscopy, nanoparticle tracking analysis, immunoblotting for exosome markers (CD9, CD63, CD81, FLOT-1) and ELISA for HLA-DR.

Results:

HIV-positive individuals had median age 52 years, 67% with suppressed plasma viral load (< 50 copies/ml), median CD4⁺ nadir 66 cells/μl and CD4⁺ cell count 313 cells/μl. CSF NFL, S100B and neopterin levels were higher in HIV-positive vs. HIV-negative individuals, and nonsuppressed vs. suppressed HIV-positive individuals. Although CSF NFL and S100B levels were higher in NCI vs. unimpaired HIV-positive individuals (P < 0.05), only NFL was associated with NCI in adjusted models (P < 0.05). CSF extracellular vesicles were increased in HIV-positive vs. HIV-negative individuals, and NCI vs. unimpaired HIV-positive individuals (P < 0.05), and correlated positively with NFL (P < 0.001). HLA-DR was enriched in CSF extracellular vesicles from HIV-positive individuals with NCI (P < 0.05), suggesting that myeloid cells are a potential source of CSF extracellular vesicles during HIV infection.

Conclusion:

Increased CSF extracellular vesicles correlate with neuronal injury biomarker NFL in cART-treated HIV-positive individuals with neurocognitive impairment, suggesting potential applications as novel biomarkers of CNS injury.

Comorbid depression and apathy in HIV-associated neurocognitive disorders in the era of chronic HIV infection

This chapter provides an overview of the current research on the question of depression and apathy in HIV-associated neurocognitive disorders (HAND) in the era of chronic HIV infection. After presenting the epidemiology of each condition showing that depression and apathy are the two most frequent psychiatric comorbidities of HAND, we review the current research, particularly in relation to the milder forms of HAND that characterize treated HIV cohorts. Doing so, we include findings on depression and apathy in non-HIV aging population and the risk of dementia, findings that are relevant to the aging HIV cohorts carrying a high burden of psychiatric comorbidities. We then present a review of the research pertaining to the differentiation between depression and apathy. A section is dedicated to the question of suicidality in chronic HIV infection, which is underappreciated. An overview of the pharmacologic and psychosocial interventions relevant to depression and apathy in HIV cohorts treated with antiretroviral treatment is provided. The chapter concludes with future directions for the research on apathy and depression with emphasis on the question of aging and the need for longitudinal studies.

Characterizing amino-acid biosignatures amongst individuals with schizophrenia: a case-control study

Amino acids and derivatives participate in the biosynthesis and downstream effects of numerous neurotransmitters. Variations in specific amino acids have been implicated in the pathophysiology of schizophrenia. Herein, we sought to compare levels of amino acids and derivatives between subjects with schizophrenia and healthy controls (HC). Two hundred and eight subjects with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria (DSM-IV)-defined schizophrenia and 175 age- and sex-matched HC were enrolled. The levels of twenty-five amino acids and seven related derivatives were measured in plasma samples using hydrophilic interaction liquid chromatography (HILIC) liquid chromatography-tandem mass spectrometry (LC-MS). After controlling for age, sex and body mass index (BMI), four amino acids and derivatives (i.e., cysteine, GABA, glutamine and sarcosine) were observed to be higher in the schizophrenia group when compared with HC; seven amino acids and derivatives were lower in the schizophrenia group (i.e., arginine, L-ornithine, threonine, taurine, tryptophan, methylcysteine, and kynurenine). Statistically significant differences in plasma amino-acid profiles between subjects with first-episode vs. recurrent schizophrenia for aspartate and glutamine were also demonstrated using generalized linear models controlling for age, sex, and BMI. The differences in amino acids and derivatives among individuals with schizophrenia when compared to HC may represent underlying pathophysiology, including but not limited to dysfunctional proteinogenic processes, alterations in excitatory and inhibitory neurotransmission, changes in ammonia metabolism and the urea cycle. Taken together, amino-acid profiling may provide a novel stratification approach among individuals with schizophrenia.

Pattern recognition receptor mRNA expression and cytokine and granzyme levels in HIV infected individuals with neurotuberculosis

Neurotuberculosis is one of the commonest HIV-associated opportunistic infections (OI) of the CNS. Cross-talk between HIV, Mycobacterium tuberculosis and host immune responses may alter expression of pattern recognition receptors (PRRs), thereby affecting cytokine profiles and functional responses. We examined PRR mRNA expression and cytokine and granzyme levels in HIV infected individuals with neurotuberculosis and found significant downregulation of TLR9 and increased MDA5 expression compared to healthy subjects. Significantly higher Granzyme A and IFN-γ levels were also observed in the CSF of this group compared to CSF from non-infectious controls. These alterations may lead to inappropriate recruitment of immune cells to the CNS, leading to disease severity.

Childhood maltreatment and HIV-associated neurocognitive disorders share similar pathophysiology: a potential sensitisation mechanism?

HIV-associated neurocognitive disorders (HAND) are increasingly prevalent despite the use of antiretroviral therapies. Previous research suggests that individual host factors play an important role in determining susceptibility to HAND. In this review, we propose that childhood trauma (CT) and HAND share several common aetiological mechanisms, namely hypothalamic-pituitary-adrenal axis dysregulation, neuroinflammation and oxidative stress. These convergent and consequent mechanisms may translate into an increased risk of developing HAND in individuals who have experienced early life stress. We provide an overview of basic and clinical research relating to these pathophysiological mechanisms and suggest that further research examine brain-derived neurotrophic factor and telomere length as common mediating factors and potential therapeutic targets for HAND and CT. Graphical abstract Both childhood trauma and HIV-associated neurocognitive disorders are associated with HPA axis dysregulation, inflammation and oxidative stress.

Oxidative Stress Markers in Tuberculosis and HIV/TB Co-Infection

INTRODUCTION

Dysfunction of redox homeostasis has been implicated in many pathological conditions. An imbalance of pro- and anti-oxidants have been observed in Tuberculosis (TB) and its co-morbidities especially HIV/AIDS. The pro inflammatory milieu in either condition aggravates the physiological balance of the redox mechanisms. The present study therefore focuses on assessing the redox status of patients suffering from TB and HIV-TB co-infection.

AIM

To assess the oxidative stress markers in the HIV-TB and TB study cohort.

MATERIALS AND METHODS

The current prospective study was conducted in Haffkine Institute, Parel, Maharashtra, India, during January 2013 to December 2015. Blood samples from 50 patients each suffering from active TB and HIV-TB co-infection were collected from Seth G.S.Medical College and KEM Hospital Mumbai and Group of Tuberculosis Hospital, Sewree Mumbai. Samples were processed and the experiments were carried out at the Department of Biochemistry, Haffkine Institute. Samples from 50 healthy volunteers were used as controls. Serum was assessed for pro-oxidant markers such as Nitric Oxide (NO), Thiobarbituric Acid Reactive Species (TBARS), C-Reactive Protein (CRP), superoxide anion. Antioxidant markers such as catalase and Superoxide Dismutase (SOD) were assessed. Total serum protein, was also assessed.

RESULTS

Among the pro-oxidants, serum NO levels were decreased in TB group while no change was seen in HIV-TB group. TBARS and CRP levels showed significant increase in both groups; superoxide anion increased significantly in HIV-TB group. Catalase levels showed decreased activities in TB group. SOD activity significantly increased in HIV-TB but not in TB group. The total serum proteins were significantly increased in HIV-TB and TB groups. The values of Control cohort were with the normal reference ranges.

CONCLUSION

In the present study, we found the presence of oxidative stress to be profound in the TB and HIV-TB co-infection population.

The crosstalk between β-catenin signaling and type I, type II and type III interferons in lung cancer cells

BACKGROUND/OBJECTIVE

IFNs induce potent antiviral and antitumor activities. β-catenin pathway is a surviving pathway adapted by carcinogenetic mechanisms of various cancers. Crosstalk between these pathways has not been well described in lung cancer cells.

METHODS

Lung cancer cell lines, A549 and Calu-3, were used in this study. β-catenin protein levels and signaling activities were tested by flow cytometry and luciferase assay. Cell proliferation was measured by counting viable cells under microscope, and apoptosis by TUNEL assay and caspase 3 activation. DKK1 and GSK3β levels were tested by flow cytometry. Secreted DKK1 was measured by ELISA. αDKK1 , FLUD and S3I were to inhibit DKK1, STAT1 and STAT3 activities, respectively.

RESULTS

All of IFNα, IFNγ and IFNλ1 suppressed β-catenin signaling in A549 and Calu-3 cells, where IFNγ was the strongest (P<0.05). They inhibited cellular proliferation and promoted apoptosis. IFNγ gave greater induction ability compared to IFNα and IFNλ1 (P<0.05). All tested IFNs promoted DKK1 activation but not GSK3β in A549 and Calu-3 cells. IFNs activated STAT1 and STAT3. But only STAT3 was vital for IFN-mediated DKK1 activation and apoptosis. Plus, DKK1 antagonist abrogated IFN-mediated apoptosis. The degree of STAT3 activation was corresponding to the level of apoptosis induced by different IFNs (P<0.05).

CONCLUSIONS

In lung cancer cells, all three types of IFNs can induce apoptosis via suppressing β-catenin signaling by a STAT3- and DKK1-dependent manner. This findings demonstrate a link between IFNs and β-catenin signaling, which may possess potentials on the development of novel therapeutic measures against lung cancer.

Brief Report: CD14+ Enriched Peripheral Cells Secrete Cytokines Unique to HIV-Associated Neurocognitive Disorders

Monocytes play a vital role in HIV-associated neurocognitive disorder (HAND), postulated to transport HIV into the brain and secrete pro-inflammatory cytokines. We analyzed cytokines released by cultured peripheral blood mononuclear cells enriched with the CD14 marker isolated from HIV-infected individuals with HAND and normal cognition (NC) in combination antiretroviral therapy naive and after 1 year on treatment. Interleukin-8 and monocyte chemoattractant protein-1 levels were higher in HAND compared with NC at baseline (P = 0.002 and P < 0.0001). These cytokines remained higher in HAND patients 1 year after combination antiretroviral therapy and were significant when NC patients who were initially HAND were excluded (P = 0.012 and P = 0.002). Both correlated with baseline CD14 peripheral blood mononuclear cell HIV DNA levels supporting the role of HIV DNA reservoir size and monocyte cytokines in HAND persistence.

Intercellular Adhesion Molecular-5 as Marker in HIV Associated Neurocognitive Disorder

Despite the use of antiretroviral drugs HIV associated neurocognitive disorders (HAND) are still common in HIV-seropositive patients. Identification of HIV patients with cognitive impairment in early-stage might benefit a great deal from disease progression monitoring and treatment adjustment. Intercellular adhesion molecule-5 (ICAM5), characteristically expressed on neuron, may suppress immune functions by inhibition of T cell activation in central nervous system. Previous studies have shown that ICAM5 could be detected in patients with brain injury. To investigate the relationship between cognitive impairment and ICAM5 in HIV patients, we compared soluble ICAM5 levels in paired CSF and plasma specimens from HIV-infected individuals with or without neurocognitive impairment. sICAM5 concentrations were measured by ICAM5 ELISA kit. A total of 41 Patients were classified into HIV infected with normal cognition (HIV-NC) and impaired cognition groups (HIV-CI) based on Memorial Sloan-Kettering Scale. CSF and plasma levels of sICAM5 in HIV-CI patients were significantly higher than HIV-NC group (p<0.0001, p=0.0054 respectively). sICAM5 concentrations in plasma strongly correlated with sICAM5 in CSF (r=0.7250, p<0.0001) and S100B in CSF (r=0.3812, p<0.0139). Among 6 follow-up patients we found that sICAM5 levels in CSF and plasma might change consistently with HAND progression. In summary, we have shown that the expressions of sICAM5 in CSF and plasma may correlate with neurocognitive impairment in HIV infected patients. The elevation of sICAM5 in plasma were correspond with that in CSF as a consequence of blood-brain barrier permeability changes. ICAM5 can serve as a potential and readily accessible biomarker to predict HIV associated neurocognitive disorder.

Cytokines, Hepatic Fibrosis, and Antiretroviral Therapy Role in Neurocognitive Disorders HIV Related

The HIV may trigger a process of neuronal loss and axonal degeneration throughout the brain, which is carried on by the immune system releasing of proinflammatory cytokines, so that chronic inflammation associated with dysregulated innate immune response, glial cell dysfunction, and adverse antiretroviral therapy (ART) effect play an important role causing milder HIV-associated neurocognitive disorders or asymptomatic neurocognitive impairment. All patients have been tested for neurocognitive functioning through a comprehensive, five-domain neuropsychological battery performed in the study. Human cytokine (interleukin [IL]-6, IL-8, IL-18, and tumor necrosis factor [TNF]-α) and brain-derived neurotrophic factor serum levels were quantified using ELISAs, and the hepatic fibrosis was estimated using the noninvasive Fibrosis 4 (FIB-4) score. The study showed a group of 40 HIV-infected individuals and it was observed that almost 40% of HIV⁺ individuals, even if clinically asymptomatic, displayed some degree of neurocognitive dysfunction, compared to normative performance standards, at least in two cognitive areas. The functions affected the most were memory, attention, executive function, and psychomotor processing speed. Three cytokines (IL-6, IL-8, and IL-18) to be significantly linked to test results in specific neurocognitive domain were found. Treatments with nucleoside reverse transcriptase inhibitor plus non-nucleoside reverse transcriptase inhibitor alone were instead associated with poor neurocognitive outcome, especially in verbal fluency, fine motility, and Zung Depression Scale. Elevated value of FIB-4 score showed an opposite connection with cognitive performance as well, underlining the direct association between hepatic steatosis and neurocognitive deficit. The cytokine panel and the FIB-4 score can predict presence or worsening of neurocognitive functions in HIV-infected individuals. An ART switch can be suggested according to the neurocognitive domain involved the most, advising a therapy with protease inhibitors or/and integrase inhibitors to improve fluency, executive functions, and to prevent depression.

Inflammatory markers are associated with decreased psychomotor speed in patients with major depressive disorder

Previous data have demonstrated that administration of inflammatory cytokines or their inducers leads to altered basal ganglia function associated with reduced psychomotor speed. Decreased psychomotor speed, referred to clinically as psychomotor retardation, is a cardinal symptom of major depressive disorder (MDD) and has been associated with poor antidepressant treatment response. We therefore examined the association between plasma inflammatory markers and psychomotor speed in ninety-three un-medicated patients with MDD. Psychomotor speed was assessed by a range of neuropsychological tests from purely motor tasks (e.g. movement latency and finger tapping) to those that involved motor activity with increasing cognitive demand and cortical participation (e.g. Trails A and Digit Symbol Substitution Task (DSST)). Linear regression analyses were performed to determine the relationship of inflammatory markers and psychomotor task performance controlling for age, race, sex, education, body mass index, and severity of depression. MDD patients exhibited decreased psychomotor speed on all tasks relative to normative standards. Increased IL-6 was associated with decreased performance on simple and choice movement time tasks, whereas MCP-1 was associated with decreased performance on the finger tapping task and DSST. IL-10 was associated with increased performance on the DSST. In an exploratory principle component analysis including all psychomotor tasks, IL-6 was associated with the psychomotor speed factor. Taken together, the data indicate that a peripheral inflammatory profile including increased IL-6 and MCP-1 is consistently associated with psychomotor speed in MDD. These data are consistent with data demonstrating that inflammation can affect basal ganglia function, and indicate that psychomotor speed may be a viable outcome variable for anti-inflammatory therapies in depression and other neuropsychiatric disorders with increased inflammation.

Cerebrospinal Fluid Biomarkers of Simian Immunodeficiency Virus Encephalitis : CSF Biomarkers of SIV Encephalitis

Antiretroviral therapy has led to increased survival of HIV-infected patients but also increased prevalence of HIV-associated neurocognitive disorders. We previously identified YKL40 as a potential cerebrospinal fluid (CSF) biomarker of lentiviral central nervous system (CNS) disease in HIV-infected patients and in the macaque model of HIV encephalitis. The aim of this study was to define the specificity and sensitivity along with the predictive value of YKL40 as a biomarker of encephalitis and to assess its relationship to CSF viral load. CSF YKL40 and SIV RNA concentrations were analyzed over the course of infection in 19 SIV-infected pigtailed macaques and statistical analyses were performed to evaluate the relationship to encephalitis. Using these relationships, CSF alterations of 31 neuroimmune markers were studied pre-infection, during acute and asymptomatic infection, at the onset of encephalitis, and at necropsy. YKL40 CSF concentrations above 1122 ng/ml were found to be a specific and sensitive biomarker for the presence of encephalitis and were highly correlated with CSF viral load. Macaques that developed encephalitis had evidence of chronic CNS immune activation during early, asymptomatic, and end stages of infection. At the onset of encephalitis, CSF demonstrated a rise of neuroimmune markers associated with macrophage recruitment, activation and interferon response. CSF YKL40 concentration and viral load are valuable biomarkers to define the onset of encephalitis. Chronic CNS immune activation precedes the development of encephalitis while some responses suggest protection from CNS lentiviral disease.

Statin modulation of monocyte phenotype and function: implications for HIV-1-associated neurocognitive disorders

HIV-1-associated neurocognitive disorder (HAND) remains a persistent problem despite antiretroviral therapy (ART), largely a result of continued inflammation in the periphery and the brain and neurotoxin release from activated myeloid cells in the CNS. CD14+CD16+ inflammatory monocytes, expanded in HIV infection, play a central role in the pathogenesis of HAND and have parallels with monocyte-dependent inflammatory mechanisms in atherosclerosis. Statins, through their HMG-CoA reductase inhibitor activity, have pleiotropic immunomodulatory properties that contribute to their benefit in atherosclerosis beyond lipid lowering. Here, we investigated whether statins would modulate the monocyte phenotype and function associated with HIV-1 neuropathogenesis. Treatment ex vivo with simvastatin and atorvastatin reduced the proportion of CD16+ monocytes in peripheral blood mononuclear cells, as well as in purified monocytes, especially CD14++CD16+ "intermediate" monocytes most closely associated with neurocognitive disease. Statin treatment also markedly reduced expression of CD163, which is also linked to HAND pathogenesis. Finally, simvastatin inhibited production of monocyte chemoattractant protein-1 (MCP-1) and other inflammatory cytokines following LPS stimulation and reduced monocyte chemotaxis in response to MCP-1, a major driver of myeloid cell accumulation in the CNS in HAND. Together, these findings suggest that statin drugs may be useful to prevent or reduce HAND in HIV-1-infected subjects on ART with persistent monocyte activation and inflammation.

Interictal cytokine levels were correlated to seizure severity of epileptic patients: a retrospective study on 1218 epileptic patients

BACKGROUND

Many aspects on the correlation between epilepsy and cytokine levels were unclear. This study aims to investigate the correlations between cytokine levels and severe epilepsy.

METHODS

Totally 1218 epileptic patients were grouped by types of epilepsy: TLE (temporal lobe epilepsy, n = 409), XLE (extra-temporal lobe epilepsy, n = 290) and IGE (idiopathic generalized epilepsy, n = 519). Two hundred healthy volunteers were as controls. Clinical findings and levels of 14 serum and CSF cytokines and 6 STAT members were collected, measured and analyzed.

RESULTS

Analysis showed no differences in interictal cytokine levels among patients from TLE, XLE and IGE groups. Interictal serum levels of IL-1b, IL-1Ra, IL-6, IL-8, IFNγ, IFNλ3 and IL-17a were associated with seizure severity of epileptic patients, measured by seizure frequency, VA score or NHS3. Multivariate regression analysis indicated that interictal concentrations of serum IL-6, IFNγ, IL-17a, IFNλ3, and CSF IL-6, IL-17a, IFNλ3 were significant biomarkers for patients with severe epilepsy. mRNA levels of IL-6, IFNγ, IL-17a, and IFNλ3 were elevated in different types of epilepsy. Activation of all STATs was elevated in epilepsy, and STAT3 was activated 9-fold in average, which was the highest among all STATs.

CONCLUSIONS

Interictal serum IL-6, IFNγ, IL-17a, IFNλ3, and CSF IL-6, IL-17a, IFNλ3 could be used as potential biomarkers for severe epilepsy. Activation of STATs, especially STAT3, was important in epilepsy. Our findings pointed out crucial roles of cytokine levels in epilepsy.