Effects of central nervous system antiretroviral penetration on cognitive functioning in the ALLRT cohort

HIV-associated neurocognitive disorders

Currently, neuropsychological impairment among HIV+ patients on antiretroviral therapy leads to a reduction in the quality of life and it is an important challenge due to the high prevalence of HIV-associated neurocognitive disorders and its concomitant consequences in relation to morbidity and mortality- including those HIV+ patients with adequate immunological and virological status. The fact that the virus is established in CNS in the early stages and its persistence within the CNS can help us to understand HIV-related brain injury even when highly active antiretroviral therapy is effective. The rising interest in HIV associated neurocognitive disorders has let to development new diagnostic tools, improvement of the neuropsychological tests, and the use of new biomarkers and new neuroimaging techniques that can help the diagnosis. Standardization and homogenization of neurocognitive tests as well as normalizing and simplification of easily accessible tools that can identify patients with increased risk of cognitive impairment represent an urgent requirement. Future efforts should also focus on diagnostic keys and searching for useful strategies in order to decrease HIV neurotoxicity within the CNS.

A Smartphone App to Screen for HIV-Related Neurocognitive Impairment

BACKGROUND

Neurocognitive Impairment (NCI) is one of the most common complications of HIV-infection, and has serious medical and functional consequences. However, screening for it is not routine and NCI often goes undiagnosed. Screening for NCI in HIV disease faces numerous challenges, such as limited screening tests, the need for specialized equipment and apparatuses, and highly trained personnel to administer, score and interpret screening tests. To address these challenges, we developed a novel smartphone-based screening tool, NeuroScreen, to detect HIV-related NCI that includes an easy-to-use graphical user interface with ten highly automated neuropsychological tests.

AIMS

To examine NeuroScreen's: 1) acceptability among patients and different potential users; 2) test construct and criterion validity; and 3) sensitivity and specificity to detect NCI.

METHODS

Fifty HIV+ individuals were administered a gold-standard neuropsychological test battery, designed to detect HIV-related NCI, and NeuroScreen. HIV+ test participants and eight potential provider-users of NeuroScreen were asked about its acceptability.

RESULTS

There was a high level of acceptability of NeuroScreen by patients and potential provider-users. Moderate to high correlations between individual NeuroScreen tests and paper-and-pencil tests assessing the same cognitive domains were observed. NeuroScreen also demonstrated high sensitivity to detect NCI.

CONCLUSION

NeuroScreen, a highly automated, easy-to-use smartphone-based screening test to detect NCI among HIV patients and usable by a range of healthcare personnel could help make routine screening for HIV-related NCI feasible. While NeuroScreen demonstrated robust psychometric properties and acceptability, further testing with larger and less neurocognitively impaired samples is warranted.

HIV-associated neurocognitive disorder in HIV-infected Koreans: the Korean NeuroAIDS Project

OBJECTIVES

HIV-associated neurocognitive disorder (HAND) is an independent predictor of early mortality and is associated with many difficulties in activities of daily living. We sought to determine the prevalence of and risk factors for HAND in HIV-infected Koreans. In addition, we investigated the performance of screening tools and components of neuropsychological (NP) tests for diagnosing HAND.

METHODS

HIV-infected patients were enrolled consecutively from two different urban teaching hospitals in Seoul, South Korea between March 2012 and September 2012. Participants completed a detailed NP assessment of six cognitive domains commonly affected by HIV. The Frascati criteria were used for diagnosing HAND. Four key questions, the International HIV Dementia Scale (IHDS) and Montreal Cognitive Assessment (MoCA)-K were also assessed as potential tools for screening for HAND.

RESULTS

Among the 194 participants, the prevalence of HAND was 26.3%. Asymptomatic neurocognitive impairment and minor neurocognitive disorder accounted for 52.9 and 47.1% of the patients with HAND, respectively. In multivariate analysis, haemoglobin (Hb) level ≤ 13 g/dL (P = 0.046) and current use of a protease inhibitor-based regimen (P = 0.031) were independent risk factors for HAND. The sensitivity and specificity of the IHDS were 72.6 and 60.8%, and those of MoCA-K were 52.9 and 73.4%, respectively. The IHDS (P < 0.001) and MoCA-K (P < 0.001) were both useful for screening for HAND. Among NP tests, the sensitivity and specificity of the Grooved Pegboard Test were 90.2 and 72.0%, and those of the Wisconsin Card Sorting Test were 61.2 and 84.4%, respectively.

CONCLUSIONS

HAND is a prevalent comorbidity in HIV-infected Koreans. Active screening and diagnosis with effective tools, such as the IHDS, MoCA-K and Grooved Pegboard Test, could be used to identify this important complication.

Antiretroviral drugs induce oxidative stress and neuronal damage in the central nervous system

HIV-associated neurocognitive disorder (HAND), characterized by a wide spectrum of behavioral, cognitive, and motor dysfunctions, continues to affect approximately 50 % of HIV(+) patients despite the success of combination antiretroviral drug therapy (cART) in the periphery. Of note, potential toxicity of antiretroviral drugs in the central nervous system (CNS) remains remarkably underexplored and may contribute to the persistence of HAND in the cART era. Previous studies have shown antiretrovirals (ARVs) to be neurotoxic in the peripheral nervous system in vivo and in peripheral neurons in vitro. Alterations in lipid and protein metabolism, mitochondrial damage, and oxidative stress all play a role in peripheral ARV neurotoxicity. We hypothesized that ARVs also induce cellular stresses in the CNS, ultimately leading to neuronal damage and contributing to the changing clinical and pathological picture seen in HIV-positive patients in the cART era. In this report, we show that ARVs are neurotoxic in the CNS in both pigtail macaques and rats in vivo. Furthermore, in vitro, ARVs lead to accumulation of reactive oxygen species (ROS), and ultimately induction of neuronal damage and death. Whereas ARVs alone caused some activation of the endogenous antioxidant response in vitro, augmentation of this response by a fumaric acid ester, monomethyl fumarate (MMF), blocked ARV-induced ROS generation, and neuronal damage/death. These findings implicate oxidative stress as a contributor to the underlying mechanisms of ARV-induced neurotoxicity and will provide an access point for adjunctive therapies to complement ARV therapy and reduce neurotoxicity in this patient population.

Long-term exposure of mice to nucleoside analogues disrupts mitochondrial DNA maintenance in cortical neurons

Nucleoside analogue reverse transcriptase inhibitor (NRTI), an integral component of highly active antiretroviral therapy (HAART), was widely used to inhibit HIV replication. Long-term exposure to NRTIs can result in mitochondrial toxicity which manifests as lipoatrophy, lactic acidosis, cardiomyopathy and myopathy, as well as polyneuropathy. But the cerebral neurotoxicity of NRTIs is still not well known partly due to the restriction of blood-brain barrier (BBB) and the complex microenvironment of the central nervous system (CNS). In this study, the Balb/c mice were administered 50 mg/kg stavudine (D4T), 100 mg/kg zidovudine (AZT), 50 mg/kg lamivudine (3TC) or 50 mg/kg didanosine (DDI) per day by intraperitoneal injection, five days per week for one or four months, and primary cortical neurons were cultured and exposed to 25 µM D4T, 50 µM AZT, 25 µM 3TC or 25 µM DDI for seven days. Then, single neuron was captured from mouse cerebral cortical tissues by laser capture microdissection. Mitochondrial DNA (mtDNA) levels of the primary cultured cortical neurons, and captured neurons or glial cells, and the tissues of brains and livers and muscles were analyzed by relative quantitative real-time PCR. The data showed that mtDNA did not lose in both NRTIs exposed cultured neurons and one month NRTIs treated mouse brains. In four months NRTIs treated mice, brain mtDNA levels remained unchanged even if the mtDNA levels of liver (except for 3TC) and muscle significantly decreased. However, mtDNA deletion was significantly higher in the captured neurons from mtDNA unchanged brains. These results suggest that long-term exposure to NRTIs can result in mtDNA deletion in mouse cortical neurons.

HIV-associated neurocognitive disorders: perspective on management strategies

Potent combination antiretroviral therapy (ART) has resulted in dramatic improvements in AIDS-associated morbidity and mortality. Although combination ART has resulted in a significant reduction in HIV-associated dementia, the most severe of the HIV-associated neurocognitive disorders (HAND), the overall prevalence of HAND among this population is estimated at 40%. It has been recognized that the central nervous system (CNS) serves as a reservoir for HIV, and neuronal damage begins at the time of acute infection and persists due to chronic infection of microglial and perivascular macrophages. Although combination ART has resulted in virologic control in the plasma compartment, virologic breakthrough can potentially ensue within the CNS compartment due to limited ART drug exposure. The purpose of this review is to discuss the definition, clinical spectrum, and risk factors associated with HAND, review the pathogenesis of HAND, and address the pharmacologic challenges associated with ART drug exposure in the CNS compartment.

HIV-associated neurocognitive disorder

Neurological involvement in HIV is often associated with cognitive impairment. Although severe and progressive neurocognitive impairment has become rare in HIV clinics in the era of potent antiretroviral therapy, most patients with HIV worldwide have poor outcomes on formal neurocognitive tests. In this Review, we describe the manifestations of HIV-associated neurocognitive disorder in the era of effective HIV therapy, outline diagnosis and treatment recommendations, and explore the research questions that remain. Although comorbid disorders, such as hepatitis C infection or epilepsy, might cause some impairment, their prevalence is insufficient to explain the frequency with which it is encountered. HIV disease markers, such as viral load and CD4 cell counts, are not strongly associated with ongoing impairment on treatment, whereas cardiovascular disease markers and inflammatory markers are. New cerebrospinal fluid and neuroimaging biomarkers are needed to detect and follow impairment. Ongoing research efforts to optimise HIV therapy within the CNS, and potentially to intervene in downstream mechanisms of neurotoxicity, remain important avenues for future investigation. Ultimately, the full control of virus in the brain is a necessary step in the goal of HIV eradication.

Genetic and non-genetic determinants of raltegravir penetration into cerebrospinal fluid: a single arm pharmacokinetic study

Background

Antiretroviral drugs vary in their central nervous system penetration, with better penetration possibly conferring neurocognitive benefit during human immunodeficiency virus (HIV) therapy. The efflux transporter gene ABCB1 is expressed in the blood-brain barrier, and an ABCB1 variant (3435C→T) has been reported to affect ABCB1 expression. The integrase inhibitor raltegravir is a substrate for ABCB1. We examined whether ABCB1 3435C→T affects raltegravir disposition into cerebrospinal fluid (CSF), and explored associations with polymorphisms in other membrane transporter genes expressed in the blood-brain barrier.

Methods

Forty healthy, HIV-negative adults of European descent (20 homozygous for ABCB1 3435 C/C, 20 homozygous for 3435 T/T, each group divided equally between males and females) were given raltegravir 400 mg twice daily for 7 days. With the final dose, plasma was collected for pharmacokinetic analysis at 9 timepoints over 12 hours, and CSF collected 4 hours post dose.

Results

The 4-hour CSF concentration correlated more strongly with 2-hour (r²=0.76, P=1.12x10^-11) than 4-hour (r²=0.47, P=6.89x10^-6) single timepoint plasma concentration, and correlated strongly with partial plasma area-under-the-curve values (AUC_0-4h r²=0.86, P=5.15x10^-16). There was no significant association between ABCB1 3435C→T and ratios of CSF-to-plasma AUC or concentration (p>0.05 for each comparison). In exploratory analyses, CSF-to-plasma ratios were not associated with 276 polymorphisms across 16 membrane transporter genes.

Conclusions

Among HIV-negative adults, CSF raltegravir concentrations do not differ by ABCB1 3435C→T genotype but strongly correlate with plasma exposure.

Trial Registration

ClinicalTrials.gov NCT00729924 http://clinicaltrials.gov/show/NCT00729924

Neuroprotective maraviroc monotherapy in simian immunodeficiency virus-infected macaques: reduced replicating and latent SIV in the brain

OBJECTIVE

HIV-associated neurocognitive deficits remain a challenge despite suppressive combined antiretroviral therapy. Given the association between HIV-induced central nervous system (CNS) disease and replication of HIV in immune-activated macrophages, CCR5 antagonists may attenuate CNS disease by modulating inflammatory signaling and by limiting viral replication.

DESIGN

To establish whether initiating CCR5 inhibition during early infection altered CNS disease progression, outcomes were compared between simian immunodeficiency virus (SIV)-infected macaques treated with maraviroc (MVC) versus untreated SIV-infected macaques.

METHODS

Six SIV-infected rhesus macaques were treated with MVC monotherapy for 5 months beginning 24 days postinoculation; 22 SIV-infected animals served as untreated controls. SIV RNA levels in plasma, cerobrospinal fluid, and brain, and CNS expression of TNFα and CCL2 were measured by qRT-PCR. Immunostaining for CD68 and amyloid precursor protein in the brain was measured by image analysis. Plasma sCD163 was measured by ELISA.

RESULTS

SIV RNA and proviral DNA levels in brain were markedly lower with MVC treatment, demonstrating CCR5 inhibition reduces CNS replication of SIV and may reduce the CNS latent viral reservoir. MVC treatment also lowered monocyte and macrophage activation, represented by CNS CD68 immunostaining and plasma sCD163 levels, and reduced both TNFα and CCL2 RNA expression in brain. Treatment also reduced axonal amyloid precursor protein immunostaining to levels present in uninfected animals, consistent with neuroprotection.

CONCLUSION

CCR5 inhibitors may prevent neurologic disorders in HIV-infected individuals by reducing inflammation and by limiting viral replication in the brain. Furthermore, CCR5 inhibitors may reduce the latent viral reservoir in the CNS. Adding CCR5 inhibitors to combined antiretroviral regimens may offer multiple neuroprotective benefits.

HIV and ageing: what the geriatrician needs to know

The transformation of human immunodeficiency virus (HIV) from a rapidly fatal disease to a chronic manageable illness has resulted in annual increases in the numbers of people living with HIV. The HIV cohort is therefore ageing, with numbers of older adults with HIV climbing, through both prolonged survival and late acquisition of the disease. Associated with ageing is an accumulation of HIV-associated non-AIDS related co-morbidities, creating a complex patient group affected by multi-morbidity along with polypharmacy, functional decline and complex social issues. With this in mind, this review seeks to explore areas where HIV (diagnosed or undetected) may impact on the work of clinical geriatricians.

Cognitive reserve during neuropsychological performance in HIV intravenous drug users

HIV-associated neurocognitive disorders are frequently observed in people with HIV. We aimed to evaluate the influence of cognitive reserve on the neuropsychological performance of seropositive drug users. We carried out a neuropsychological assessment and compared the performance of seropositive drug users (n = 75) with that of a group of seronegative drug users (n = 48). The results showed that a low cognitive reserve makes the seropositive patients neuropsychologically vulnerable. Likewise, we found that a high cognitive reserve has a protective effect in the presence of neuropsychological impairment associated with HIV. In the seronegative group, differences in a small number of tests were found between participants with low and high cognitive reserve. Overall, these data suggest that seropositivity is not sufficient to explain the neuropsychological alterations of seropositive drug users; rather, these alterations are multifactorial.

HIV and neurocognitive dysfunction

The spectrum of HIV-associated neurocognitive disorder (HAND) has been dramatically altered in the setting of widely available effective antiretroviral therapy (ART). Once culminating in dementia in many individuals infected with HIV, HAND now typically manifests as more subtle, though still morbid, forms of cognitive impairment in persons surviving long-term with treated HIV infection. Despite the substantial improvement in severity of this disorder, the fact that neurologic injury persists despite ART remains a challenge to the community of patients, providers and investigators aiming to optimize quality of life for those living with HIV. Cognitive dysfunction in treated HIV may reflect early irreversible CNS injury accrued before ART is typically initiated, ongoing low-level CNS infection and progressive injury in the setting of ART, or comborbidities including effects of treatment which may confound the beneficial reduction in viral replication and immune activation effected by ART.

HIV-Associated Neurocognitive Disorders—An Issue of Growing Importance

Introduction: HIV-associated neurocognitive disorders (HAND) comprise a wide spectrum of cognitive, motor, and mood abnormalities prevalent in people living with HIV and AIDS (PLWHAs). This field of HIV medicine has gained renewed prominence in recent years with evidence contending that anti-retroviral agents with increased central nervous system (CNS) penetration may improve neurocognitive outcomes in those affected. This review aims at evaluating the available evidence and postulating further study direction in Singapore. Materials and Methods: A PubMed search was carried out for original articles and systematic reviews on the subject of HIV-associated neurocognitive disorders, and the results reviewed by the authors. Results: There is a growing body of evidence that HAND is not uncommon, and the advent of highly active anti-retroviral therapy has increased its prevalence by improving the prognosis of HIV infection, and hence increasing the likelihood of diagnosing of this neurocognitive condition. Screening and diagnosing HAND is important, and requires clinical suspicion as well as validated test batteries for optimal accuracy. The authors recommend strategies for detection in the local context involving stepwise targeted screening. Anti-retroviral agents with good CNS penetration and activity, as well as adjunctive neuro-rehabilitative interventions, may improve the impairments experienced by affected individuals. Conclusion: Increased awareness of HAND, with earlier diagnosis and targeted, multi-disciplinary management of this challenging condition, may lead to better all-round outcomes for people living with HIV and AIDS in Singapore. Key words: AIDS, Cognition, Dementia, HAART

HIV, dementia and antiretroviral drugs: 30 years of an epidemic

Neurological complications due to the HIV itself became apparent early on in the course of the AIDS epidemic. The most feared were the cognitive and motor complications termed AIDS dementia complex or HIV-associated dementia. With the introduction of combination antiretroviral therapy, the incidence of HIV-associated dementia has been dramatically reduced. However, the prevalence of less severe forms of the disorder remains around 20%. There is controversy about whether some patients may continue with progressive cognitive decline despite adequate suppression of the HIV. The salient issues are those of cerebrospinal fluid (CSF) drug penetration, drug neurotoxicity and persistent immune activation and inflammation. This review will also discuss other newly encountered complications, including the compartmentalisation (or CSF escape) and immune reconstitution inflammatory syndromes.

Approach to cerebrospinal fluid (CSF) biomarker discovery and evaluation in HIV infection

Central nervous system (CNS) infection is a nearly universal facet of systemic HIV infection that varies in character and neurological consequences. While clinical staging and neuropsychological test performance have been helpful in evaluating patients, cerebrospinal fluid (CSF) biomarkers present a valuable and objective approach to more accurate diagnosis, assessment of treatment effects and understanding of evolving pathobiology. We review some lessons from our recent experience with CSF biomarker studies. We have used two approaches to biomarker analysis: targeted, hypothesis-driven and non-targeted exploratory discovery methods. We illustrate the first with data from a cross-sectional study of defined subject groups across the spectrum of systemic and CNS disease progression and the second with a longitudinal study of the CSF proteome in subjects initiating antiretroviral treatment. Both approaches can be useful and, indeed, complementary. The first is helpful in assessing known or hypothesized biomarkers while the second can identify novel biomarkers and point to broad interactions in pathogenesis. Common to both is the need for well-defined samples and subjects that span a spectrum of biological activity and biomarker concentrations. Previously-defined guide biomarkers of CNS infection, inflammation and neural injury are useful in categorizing samples for analysis and providing critical biological context for biomarker discovery studies. CSF biomarkers represent an underutilized but valuable approach to understanding the interactions of HIV and the CNS and to more objective diagnosis and assessment of disease activity. Both hypothesis-based and discovery methods can be useful in advancing the definition and use of these biomarkers.

Virological efficacy in cerebrospinal fluid and neurocognitive status in patients with long-term monotherapy based on lopinavir/ritonavir: an exploratory study

BACKGROUND

Data on suppression of HIV replication in the CNS and on the subsequent risk of neurocognitive impairment using monotherapy with boosted protease inhibitors are limited.

METHODS

Ours was an exploratory cross-sectional study in patients on lopinavir/ritonavir-based monotherapy (LPV/r-MT) or standard triple therapy (LPV/r-ART) for at least 96 weeks who maintained a plasma viral load <50 copies/mL. HIV-1 RNA in CSF was determined by HIV-1 SuperLow assay (lower limit of detection, 1 copy/mL). Neurocognitive functioning was assessed using a recommended battery of neuropsychological tests covering 7 areas. Neurocognitive impairment (NCI) was determined and also a global deficit score (GDS) for study comparisons.

RESULTS

Seventeen patients on LPV/r-MT and 17 on LPV/r-ART were included. Fourteen (82.4%) patients on LPV/r-MT and 16 (94.1%) on LPV/r-ART had HIV-1 RNA <1 copy/mL in CSF (p = 0.601). NCI was observed in 7 patients on LPV/r-MT and in 10 on LPV/r-ART (41% vs 59%; p = 0.494). Mean (SD) GDS was 0.22 (0.20) in patients on LPV/r-MT and 0.47 (0.34) in those on LPV/r-ART (p = 0.012).

CONCLUSIONS

Suppression of HIV in CSF is similar in individuals with durable plasma HIV-1 RNA suppression who are receiving LPV/r-MT or LPV/r-ART for at least 96 weeks. Findings for HIV-1 replication in CSF and neurocognitive status indicate that this strategy seems to be safe for CNS functioning.

Neurocognitive impairment in patients treated with protease inhibitor monotherapy or triple drug antiretroviral therapy

Background

In patients who remain virologically suppressed in plasma with triple-drug ART a switch to protease inhibitor monotherapy maintains high rates of suppression; however it is unknown if protease inhibitor monotherapy is associated to a higher rate of neurocognitive impairment.

Methods

In this observational, cross-sectional study we included patients with plasma virological suppression (≥1 year) without concomitant major neurocognitive confounders, currently receiving for ≥1 year boosted lopinavir or darunavir as monotherapy or as triple ART. Neurocognitive impairment was defined as per the 2007 consensus of the American Association of Neurology. The association between neurocognitive impairment and protease inhibitor monotherapy, adjusted by significant confounders, was analysed.

Results

Of the 191 included patients - triple therapy: 96, 1–2 years of monotherapy: 40 and >2 years of monotherapy: 55 - proportions (95% CI) with neurocognitive impairment were: overall, 27.2% (20.9–33.6); triple therapy, 31.6% (22.1–41.0); short-term monotherapy, 25.0% (11.3–38.7); long-term monotherapy: 21.4% (10.5–32.3); p = 0.38. In all groups, neurocognitive impairment was mildly symptomatic or asymptomatic by self-report. There were not significant differences in Global Deficit Score by group. In the regression model confounding variables for neurocognitive impairment were years on ART, ethnicity, years of education, transmission category and the HOMA index. Adjusted by these variables the Odds Ratio (95% CI) for neurocognitive impairment of patients receiving short-term monotherapy was 0.85 (0.29–2.50) and for long-term monotherapy 0.40 (0.14–1.15).

Conclusions

Compared to triple drug antiretroviral therapy, monotherapy with lopinavir/ritonavir or darunavir/ritonavir in patients with adequate plasma suppression was not associated with a higher rate of asymptomatic neurocognitive impairment than triple drug ART.

Monocyte/macrophages and their role in HIV neuropathogenesis

Neurological sequelae of human immunodeficiency virus (HIV) infection have been and remain a significant problem. Monocytes and macrophages in humans and monkeys are susceptible to infection by HIV and simian immunodeficiency virus (SIV), and are considered to be a main mechanism by which the central nervous system (CNS) is infected. Within the infected CNS, perivascular macrophages and, in some cases, parenchymal microglia are infected as are multinucleated giant cells when present. While neurons are not themselves directly infected, neuronal damage occurs within the infected CNS. Despite the success of antiretroviral therapy (ART) in limiting virus in plasma to non-detectable levels, neurological deficits persist. This review discusses the continued neurological dysfunctions that persist in the era of ART, focusing on the roles of monocyte and macrophage as targets of continued viral infection and as agents of pathogenesis in what appears to be emergent macrophage-mediated disease resulting from long-term HIV infection of the host. Data discussed include the biology of monocyte/macrophage activation with HIV and SIV infection, traffic of cells into and out of the CNS with infection, macrophage-associated biomarkers of CNS and cardiac disease, the role of antiretroviral therapy on these cells and CNS disease, as well as the need for effective adjunctive therapies targeting monocytes and macrophages.

Cellular Composition of Cerebrospinal Fluid in HIV-1 Infected and Uninfected Subjects

In order to characterize the cellular composition of cerebrospinal fluid (CSF) in a healthy state and in the setting of chronic pleocytosis associated with HIV-1 (HIV) infection, multi-parameter flow cytometry was used to identify and quantitate cellular phenotypes in CSF derived from HIV-uninfected healthy controls and HIV-infected subjects across a spectrum of disease and treatment. CD4+ T cells were the most frequent CSF population and the CD4:CD8 ratio was significantly increased in the CSF compared to blood (p = 0.0232), suggesting preferential trafficking of CD4+ over CD8+ T cells to this compartment. In contrast, in HIV-infection, CD8+ T cells were the major cellular component of the CSF and were markedly increased compared to HIV-uninfected subjects (p<0.001). As with peripheral blood, the CSF CD4:CD8 ratio was reversed in HIV-infected subjects compared to HIV-uninfected subjects. Monocytes, B cells and NK cells were rare in the CSF in both groups, although absolute counts of CSF NK cells and B cells were significantly increased in HIV-infected subjects (p<0.05). Our studies show that T cells are the major cellular component of the CSF in HIV-infected and uninfected subjects. The CSF pleocytosis characteristic of HIV infection involves all lymphocyte subsets we measured, except for CD4+ T cells, but is comprised primarily of CD8+ T cells. The reduced proportion of CD4+ T cells in the CSF may reflect both HIV-related peripheral loss and changes in trafficking patterns in response to HIV infection in the central nervous system.

Neurologic abnormalities in HIV-1 infected children in the era of combination antiretroviral therapy

Background

Pediatric HIV-1 infection is associated with neurologic abnormalities. In recent years, the neurological outcome of HIV-1 infected children has substantially improved with combination antiretroviral therapy (cART). However, data regarding the long-term effect of cART and neurologic outcome are limited.

Methods

In the Pediatric Amsterdam Cohort on HIV-1 study, 59 perinatally HIV-1 infected children were evaluated from 1992–2010. All children underwent neurological examination and neuro-imaging studies, including CT-scan and/or MRI imaging. Fisher exact and Kruskal-Wallis tests were used to compare clinical deviations of neuro-imaging studies with HIV-1 related parameters, including CD4⁺ T cell count, HIV-1 viral load in blood and cerebrospinal fluid (CSF), and duration of cART as well as neurological examination.

Results

Abnormal neurologic examinations in these HIV-1 infected children included language impairment (22%), abnormal muscle tone (hyper/hypotonia) (14%) and delay in reaching developmental milestones (12%). Ventricular enlargement and sulcal widening (29%) and white matter lesions (38%) were prominent findings. White matter lesions were positively correlated with HIV-1 viral load levels. In a small follow-up sub study white matter lesions did not improve while children with ventricular enlargement and sulcal widening showed improvements whilst being treated with cART.

Conclusions

In the current era of cART HIV-1 infected children still frequently show neurological impairments together with abnormal neuro-imaging.

Neurologic complications of HIV-1 infection and its treatment in the era of antiretroviral therapy

PURPOSE OF REVIEW

Neurologic complications of HIV infection are unfortunately common, even in the era of effective antiretroviral treatment (ART). The consulting neurologist is often asked to distinguish among neurologic deterioration due to opportunistic infection (OI), immune reconstitution, or the effect of the virus itself, and to comment on the role of immunomodulatory agents in patients with HIV infection. Additionally, as successful virologic control has extended the life span of patients with HIV infection, neurologists are called upon to manage long-term complications, such as neurocognitive disorders and peripheral neuropathy.

RECENT FINDINGS

Despite the use of ART, significant numbers of patients continue to be affected by HIV-associated neurocognitive disorders, although with milder forms compared to the pre-ART era. Regimens of ART have been ranked according to CNS penetration and are being studied with regard to neuropsychological outcomes. Nucleoside analogs with the greatest potential for peripheral neurotoxicity are no longer considered first-line agents for HIV treatment. Efavirenz, a non-nucleoside reverse transcriptase inhibitor, has the greatest frequency of neurologic side effects among newer ART regimens. The spectrum of clinical manifestations of immune reconstitution inflammatory syndrome (IRIS) continues to grow, including IRIS without underlying OI. A greater understanding of pathophysiology and risk factors has shown that while HIV should be treated early to prevent severe immunocompromise, delayed initiation of ART may be helpful while treating OIs.

SUMMARY

This article reviews the neurologic complications of HIV infection, or its treatment, most commonly encountered by neurologists.

A light in the cognitive fog?

HIV escape in the central nervous system (CNS) despite undetectable viral load in the plasma has been observed and may contribute to HIV-associated neurocognitive disorders. Favouring the use of HIV drugs with a good penetration into the CNS has been advocated, leading to the establishment of the CNS penetration-effectiveness (CPE) score. However, the relevance of this score is not fully established. Ciccarelli et al. compared two versions of the CPE scores in their capacity to predict cognitive dysfunction in HIV-infected individuals. The revised CPE score, but not the original one, showed an improved association with cognitive impairment. Prospective studies are warranted to assess the validity of the CPE score.

NRTI backbone in HIV treatment: will it remain relevant?

Nucleoside reverse transcriptase inhibitors (NRTIs) remain a critical component of therapy for HIV-infected patients. The drugs are effective, relatively inexpensive and an important component of antiretroviral therapy (ART), particularly in areas where the introduction of effective therapy has been delayed. They are an essential part of initial therapy for HIV and for prevention of mother-to-child transmission; however, toxicities and resistance may limit their use. The role for pre-exposure prophylaxis (PrEP) to reduce sexual transmission of HIV is still undefined, but this use may have a significant impact on NRTI resistance worldwide, most particularly in areas where subtype C predominates. With increasing prevalence of resistant HIV, the approval of new agents that are effective against resistant virus, and those that use novel cellular targets, are essential. Large studies are now in progress examining the safety and efficacy of NRTI-sparing regimens, but results are not currently available. NRTIs may lose relevance in the not distant future unless steps are put in place to reduce the development and spread of NRTI-resistant viruses, and new NRTIs with minimal toxicity are developed that have a novel resistance profile. This article describes the principal NRTIs, their mechanism of action, and resistance and selected toxicities of the class and of the individual drugs.

Cognitive neurorehabilitation of HIV-associated neurocognitive disorders: a qualitative review and call to action

Despite significant advances in the virologic management of HIV infection over the last two decades, effective treatments for HIV-associated neurocognitive disorders (HAND) remain elusive. While pharmacological interventions have yielded some success in improving neurocognitive outcomes in HIV, there is a dearth of rigorous studies examining the efficacy of cognitive rehabilitation for remediating HIV-associated neurocognitive impairment. This qualitative review summarizes and critiques the emerging literature on cognitive and behavioral treatments for HAND, which provides many reasons for optimism, but also has major limitations that underscore the scope of the work that lies ahead. Considering the notable real-world consequences of HAND, the development, validation, and clinical deployment of cognitive neurorehabilitation interventions tailored to the needs of persons living with HIV infection is a priority for clinical neuroAIDS investigators. In describing potential future directions for this endeavor, particular attention was paid to the application of cognitive neuropsychological principles in developing theory-driven approaches to managing HAND, improving everyday functioning, and enhancing HIV health outcomes.

Neurologic Complications and Considerations in HIV-Infected Persons

Neurologic complications for HIV-infected persons retain significant prevalence despite an increasingly global use of antiretroviral therapies. Such complications are often ascribed to advanced immunosuppression; however, the most common neurologic problems for HIV-infected persons, distal sensory polyneuropathy and HIV-associated neurocognitive disorders, affect a significant proportion of patients who have successfully achieved immunologic restoration with normal or near-normal CD4 count levels and undetectable HIV RNA in the periphery. Understanding specific considerations for HIV-associated complications, including the epidemiology, risk factors, medication-adverse effects, and benefits of appropriate management, is vital for all providers caring for those with HIV. This review will describe such considerations, as well as providing a more detailed review of the most common neurologic complications of HIV infection, and will highlight some of the challenges involved with diagnosis, management, and long-term effects.

Cognitive disorders in HIV-infected patients: are they HIV-related?

OBJECTIVES

Large unselected studies on representative samples of HIV-infected patients with a whole battery of neuropsychological tests and cerebral MRI scan are required to assess the frequency of neurocognitive impairment (NCI), the determinants of mild neurocognitive disorders (MNDs), or HIV-associated dementia (HAD) and the relationship between NCI and MRI scan findings.

METHODS

Investigation of 400 consecutively enrolled HIV-1-infected adults from the ANRS CO3 Aquitaine Cohort, using standardized neurocognitive tests chosen to achieve consistency with Frascati's criteria. Half of the patients had a cerebral MRI scan allowing gray and white matter volume measurement. Factors associated with NCI were studied by logistic regression models.

RESULTS

Median age of participants was 47 years, 79% were male and 89% received combination antiretroviral treatment (cART), of whom 93% had plasma HIV RNA below 500 copies/ml. Median CD4 cell count was 515 cells/μl. Prevalence of NCI was 59%, including 21% of asymptomatic NCI, 31% of MND, and 7% of HAD. A low level of education, prior neurologic AIDS-defining disorders event, anxiety, depressive symptoms, and prior history of brain damage were independently associated with MND or HAD, but neither HIV nor cART-related variables. The presence of NCI was significantly associated with lower gray matter fraction.

INTERPRETATION

In this large unselected cohort, a high prevalence of symptomatic neurocognitive disorders was mainly related to its traditional determinants and associated with gray matter atrophy at early stages of the disease.

CSF penetration by antiretroviral drugs

Severe HIV-associated neurocognitive disorders (HAND), such as HIV-associated dementia, and opportunistic CNS infections are now rare complications of HIV infection due to comprehensive highly active antiretroviral therapy (HAART). By contrast, mild to moderate neurocognitive disorders remain prevalent, despite good viral control in peripheral compartments. HIV infection seems to provoke chronic CNS injury that may evade systemic HAART. Penetration of antiretroviral drugs across the blood-brain barrier might be crucial for the treatment of HAND. This review identifies and evaluates the available clinical evidence on CSF penetration properties of antiretroviral drugs, addressing methodological issues and discussing the clinical relevance of drug concentration assessment. Although a substantial number of studies examined CSF concentrations of antiretroviral drugs, there is a need for adequate, well designed trials to provide more valid drug distribution profiles. Neuropsychological benefits and neurotoxicity of potentially CNS-active drugs require further investigation before penetration characteristics will regularly influence therapeutic strategies and outcome.

Dendritic spine injury induced by the 8-hydroxy metabolite of efavirenz

Despite combination antiretroviral therapies (cARTs), a significant proportion of HIV-infected patients develop HIV-associated neurocognitive disorders (HAND). Ongoing viral replication in the central nervous system (CNS) caused by poor brain penetration of cART may contribute to HAND. However, it has also been proposed that the toxic effects of long-term cART may contribute to HAND. A better understanding of the neurotoxic potential of cART is critically needed in light of the use of CNS-penetrating cARTs to contend with the virus reservoir in the brain. The efavirenz (EFV) metabolites 7-hydroxyefavirenz (7-OH-EFV) and 8-hydroxyefavirenz (8-OH-EFV) were synthesized and purified, and their chemical structures were confirmed by mass spectrometry and NMR. The effects of EFV, 7-OH-EFV, and 8-OH-EFV on calcium, dendritic spine morphology, and survival were determined in primary neurons. EFV, 7-OH-EFV, and 8-OH-EFV each induced neuronal damage in a dose-dependent manner. However, 8-OH-EFV was at least an order of magnitude more toxic than EFV or 7-OH-EFV, inducing considerable damage to dendritic spines at a 10 nM concentration. The 8-OH-EFV metabolite evoked calcium flux in neurons, which was mediated primarily by L-type voltage-operated calcium channels (VOCCs). Blockade of L-type VOCCs protected dendritic spines from 8-OH-EFV-induced damage. Concentrations of EFV and 8-OH-EFV in the cerebral spinal fluid of HIV-infected subjects taking EFV were within the range that damaged neurons in culture. These findings demonstrate that the 8-OH metabolite of EFV is a potent neurotoxin and highlight the importance of directly determining the effects of antiretroviral drugs and drug metabolites on neurons and other brain cells.

Antiretroviral monocyte efficacy score linked to cognitive impairment in HIV

BACKGROUND

Monocytes transmigrating to the brain play a central role in HIV neuropathology. We hypothesized that the continued existence of neurocognitive impairment (NCI) despite potent antiretroviral (ARV) therapy is mediated by the inability of such therapy to control this monocyte/macrophage reservoir.

METHODS

Cross-sectional and longitudinal analyses were conducted within a prospectively enrolled cohort. We devised a monocyte efficacy (ME) score based on the anticipated effectiveness of ARV medications against monocytes/macrophages using published macrophage in vitro drug efficacy data. We examined, within an HIV neurocognitive database, its association with composite neuropsychological test scores (NPZ8) and clinical cognitive diagnoses among subjects on stable ARV medications unchanged for >6 months prior to assessment.

RESULTS

Among 139 subjects on ARV therapy, higher ME score correlated with better NPZ8 performance (r=0.23, P<0.01), whereas a score devised to quantify expected penetration effectiveness of ARVs into the brain (CPE score) did not (r=0.12, P=0.15). In an adjusted model (adjusted r(2)=0.12), ME score (β=0.003, P=0.02), CD4(+) T-cell nadir (β=0.001, P<0.01) and gender (β=-0.456, P=0.02) were associated with NPZ8, whereas CPE score was not (β=0.003, P=0.94). A higher ME score was associated with better clinical cognitive status (P<0.01). With a range of 12.5-433.0 units, a 100-unit increase in ME score resulted in a 10.6-fold decrease in the odds of a dementia diagnosis compared with normal cognition (P=0.01).

CONCLUSIONS

ARV efficacy against monocytes/macrophages correlates with cognitive function in HIV-infected individuals on ARV therapy within this cohort. If validated, efficacy against monocytes/macrophages may provide a new target to improve HIV NCI.

Targeting chronic central nervous system HIV infection

Central nervous system (CNS) HIV infection is a nearly universal facet of systemic infection. Although antiretroviral therapy is generally effective in suppressing this infection and reducing its severe complications, reports of continued neurological abnormalities have questioned whether treatment developed for systemic efficacy is optimized for CNS infection. Shikuma et al. report that a 'monocyte efficacy' score based on cell culture studies and applied to antiretroviral drugs correlated with neuropsychological performance in a previously reported cohort. Although there are important questions regarding the theoretical underpinnings of both this score and its application, the findings present a novel slant on therapy.

Cardiovascular risk factors and carotid intima-media thickness are associated with lower cognitive performance in HIV-infected patients

OBJECTIVES

The aim of the study was to investigate the relationship between metabolic comorbidities, cardiovascular risk factors or common carotid intima-media thickness (cIMT) and cognitive performance in HIV-infected patients.

METHODS

Asymptomatic HIV-infected subjects were consecutively enrolled during routine out-patient visits at two clinical centres. All patients underwent an extensive neuropsychological battery and assessment of metabolic comorbidities and cardiovascular risk factors. Moreover, cIMT was assessed by ultrasonography. Cognitive performance was evaluated by calculating a global cognitive impairment (GCI) score obtained by summing scores assigned to each test (0 if normal and 1 if pathological).

RESULTS

A total of 245 patients (median age 46 years; 84.1% with HIV RNA < 50 copies/mL; median CD4 count 527 cells/μL) were enrolled in the study. Cardiovascular risk factors were highly prevalent in our population: the most frequent were dyslipidaemia (61.2%), cigarette smoking (54.3%) and hypertension (15.1%). cIMT was abnormal (≥ 0.9mm) in 31.8% of patients. Overall, the median GCI score was 2 [interquartile range (IQR) 1-4]; it was higher in patients with diabetes (P = 0.004), hypertension (P = 0.030) or cIMT ≥ 0.9 mm (P < 0.001). In multivariate analysis, it was confirmed that diabetes (P = 0.007) and cIMT ≥ 0.9 mm (P = 0.044) had an independent association with lower cognitive performance. In an analysis of patients on combination antiretroviral therapy (cART), abacavir use was independently associated with a better cognitive performance (P = 0.011), while no association was observed for other drugs or neuroeffectiveness score.

CONCLUSIONS

Diabetes, cardiovascular risk factors and cIMT showed a strong association with lower cognitive performance, suggesting that metabolic comorbidities could play a relevant role in the pathogenesis of HIV-associated neurocognitive disorders in the recent cART era.

Neurocognitive impairment in patients randomized to second-line lopinavir/ritonavir-based antiretroviral therapy vs. lopinavir/ritonavir monotherapy

We compared rates of neurocognitive impairment (NCI) among 93 Thai adults failing non-nucleoside reverse transcriptase inhibitor (NNRTI)-based combination antiretroviral therapy (cART) before and after switching to lopinavir/ritonavir monotherapy (mLPV/r) vs. tenofovir/lamivudine/LPV/r (TDF/3TC/LPV/r). Participants completed the Color Trails 1 and 2, Digit Symbol, and Grooved Pegboard at weeks 0, 24, and 48. We calculated z-scores using normative data from 451 healthy HIV-negative Thais. We defined NCI as performance of <-1 SD on ≥2 tests. The Thai depression inventory was used to capture depressive symptoms. Lumbar puncture was optional at week 0 and 48. At baseline, median (IQR) age was 36.9 (32.8-40.5) years, and 46 % had primary school education or lower. The median CD4 count was 196 (107-292) cells/mm(3), and plasma HIV RNA was 4.1 (3.6-4.5) log(10) copies/ml. Almost all (97 %) had circulating recombinant CRF01_AE. At baseline, 20 (47 %) of the mLPV/r vs. 22 (44 %) of TDF/3TC/LPV/r arms met NCI criteria (p = 0.89). The frequency of NCI at week 48 was 30 vs. 32 % (p = 0.85) with 6 vs. 7 % (p = 0.85) developing NCI in the mLPV/r vs. TDF/3TC/LPV/r arms, respectively. Having NCI at baseline and lower education each predicted NCI at week 48. Depression scores at week 48 did not differ between arms (p = 0.47). Cerebrospinal fluid HIV RNA of <50 copies/ml at 48 weeks was observed in five out of seven in mLPV/r vs. three out of four in TDF/3TC/LPV/r arm. The rates of NCI and depression did not differ among cases failing NNRTI-based cART who received mLPV/r compared to LPV/r triple therapy.

Cerebrospinal fluid HIV escape associated with progressive neurologic dysfunction in patients on antiretroviral therapy with well controlled plasma viral load

OBJECTIVE

To characterize HIV-infected patients with neurosymptomatic cerebrospinal fluid (CSF) 'escape', defined as detectable CSF HIV RNA in the setting of treatment-suppressed plasma levels or CSF RNA more than 1-log higher than plasma RNA.

DESIGN

Retrospective case series.

SETTING

Four urban medical centers in the United States and Europe.

PARTICIPANTS

Virologically controlled HIV-infected patients on antiretroviral therapy (ART) with progressive neurologic abnormalities who were determined to have CSF 'escape'. INTERVENTION Optimization of ART based upon drug susceptibility and presumed central nervous system exposure.

MAIN OUTCOME MEASURES

Levels of CSF HIV RNA and inflammatory markers, clinical signs and symptoms, and MRI findings.

RESULTS

Ten patients presented with new neurologic abnormalities, which included sensory, motor, and cognitive manifestations. Median CSF HIV RNA was 3900 copies/ml (range 134-9056), whereas median plasma HIV RNA was 62 copies/ml (range <50 to 380). Median CD4 T-cell count was 482 cells/μl (range 290-660). All patients had been controlled to less than 500 copies/ml for median 27.5 months (range 2-96) and five of 10 had been suppressed to less than 50 copies/ml for median 19.5 months (range 2-96). Patients had documentation of a stable ART regimen for median 21 months (range 9-60). All had CSF pleocytosis or elevated CSF protein; seven of eight had abnormalities on MRI; and six of seven harbored CSF resistance mutations. Following optimization of ART, eight of nine patients improved clinically.

CONCLUSION

The development of neurologic symptoms in patients on ART with low or undetectable plasma HIV levels may be an indication of CSF 'escape'. This study adds to a growing body of literature regarding this rare condition in well controlled HIV infection.

Regional brain structural dysmorphology in human immunodeficiency virus infection: effects of acquired immune deficiency syndrome, alcoholism, and age

BACKGROUND

Human immunodeficiency virus (HIV) infection and alcoholism each carries liability for disruption of brain structure and function integrity. Despite considerable prevalence of HIV-alcoholism comorbidity, few studies examined the potentially heightened burden of disease comorbidity.

METHODS

Participants were 342 men and women: 110 alcoholics, 59 with HIV infection, 65 with HIV infection and alcoholism, and 108 healthy control subjects. This design enabled examination of independent and combined effects of HIV infection and alcoholism along with other factors (acquired immune deficiency syndrome [AIDS]-defining events, hepatitis C infection, age) on regional brain volumes derived from T1-weighted magnetic resonance images.

RESULTS

Brain volumes, expressed as Z scores corrected for intracranial volume and age, were measured in 20 tissue and 5 ventricular and sulcal regions. The most profound and consistent volume deficits occurred with alcohol use disorders, notable in the cortical mantle, insular and anterior cingulate cortices, thalamus, corpus callosum, and frontal sulci. The HIV-only group had smaller thalamic and larger frontal sulcal volumes than control subjects. HIV disease-related factors associated with greater volume abnormalities included CD4 cell count nadir, clinical staging, history of AIDS-defining events, infection age, and current age. Longer sobriety and less lifetime alcohol consumption were predictive of attenuated brain volume abnormalities in both alcohol groups.

CONCLUSIONS

Having HIV infection with alcoholism and AIDS had an especially poor outcome on brain structures. That longer periods of sobriety and less lifetime alcohol consumption were predictive of attenuated brain volume abnormalities encourages the inclusion of alcohol recovery efforts in HIV/AIDS therapeutic settings.

Eliminating the HIV reservoir

In the past few years, major advances have been achieved in understanding the nature and the maintenance mechanisms of the HIV reservoir. Although antiretroviral therapy works well in a majority of patients, it faces problems of compliance, resistance, toxicity, and cost. In most cases, the remaining HIV reservoir precluding antiretroviral cessation consists of a tiny cell pool that is long-lived and inaccessible to current therapies. New strategies are therefore needed to either purge or control this residual reservoir and finally stop antiretroviral drugs. Both ways leading to a functional or a sterilizing cure are currently pursued. Several molecules have been identified to achieve these goals and some of them have already entered clinical testing in humans. In this article, we review recent findings on the biology of HIV persistence and detail how HIV eradication trials should be designed in the near future.

HIV-1-related central nervous system disease: current issues in pathogenesis, diagnosis, and treatment

HIV-associated central nervous system (CNS) injury continues to be clinically significant in the modern era of HIV infection and therapy. A substantial proportion of patients with suppressed HIV infection on optimal antiretroviral therapy have impaired performance on neuropsychological testing, suggesting persistence of neurological abnormalities despite treatment and projected long-term survival. In the underresourced setting, limited accessibility to antiretroviral medications means that CNS complications of later-stage HIV infection continue to be a major concern. This article reviews key recent advances in our understanding of the neuropathogenesis of HIV, focusing on basic and clinical studies that reveal viral and host features associated with viral neuroinvasion, persistence, and immunopathogenesis in the CNS, as well as issues related to monitoring and treatment of HIV-associated CNS injury in the current era.

Lower than expected maraviroc concentrations in cerebrospinal fluid exceed the wild-type CC chemokine receptor 5-tropic HIV-1 50% inhibitory concentration

To measure maraviroc total cerebrospinal fluid (CSF) concentrations and compare them with total and unbound plasma concentrations. Total maraviroc was measured by reverse-phase high-performance liquid chromatography with tandem mass spectrometry, whereas ultrafiltration was used for unbound maraviroc. Maraviroc was detected in all nine CSF/plasma pairs with a median CSF total concentration of 2.4 ng/ml. CSF concentrations exceeded the 50% inhibitory concentration of wild-type CC chemokine receptor 5-tropic HIV-1 in all specimens. CSF concentrations are lower than expected based on plasma concentrations and physicochemical characteristics. Unbound maraviroc plasma concentrations may be informative in estimating concentrations in CSF.

Neurocognitive and motor deficits in HIV-infected Ugandan children with high CD4 cell counts

BACKGROUND

Human immunodeficiency virus (HIV) infection causes neurocognitive or motor function deficits in children with advanced disease, but it is unclear whether children with CD4 cell measures above the World Health Organization (WHO) thresholds for antiretroviral therapy (ART) initiation suffer significant impairment.

METHODS

The neurocognitive and motor functions of HIV-infected ART-naive Ugandan children aged 6-12 years with CD4 cell counts of >350 cells/μL and CD4 cell percentage of >15% were compared with those of HIV-uninfected children, using the Test of Variables of Attention (TOVA), the Kaufman Assessment Battery for Children, second edition (KABC-2), and the Bruininks-Oseretsky Test of Motor Proficiency, second edition (BOT-2).

RESULTS

Ninety-three HIV-infected children (median CD4 cell count, 655 cells/μL; plasma HIV RNA level, 4.7 log(10) copies/mL) were compared to 106 HIV-uninfected children. HIV-infected children performed worse on TOVA visual reaction times (multivariate analysis of covariance; P = .006); KABC-2 sequential processing (P = .005), simultaneous processing (P = .039), planning/reasoning (P = .023), and global performance (P = .024); and BOT-2 total motor proficiency (P = .003). High plasma HIV RNA level was associated with worse performance in 10 cognitive measures and 3 motor measures. In analysis of only WHO clinical stage 1 or 2 HIV-infected children (n = 68), significant differences between the HIV-infected and HIV-uninfected groups (P < .05) remained for KABC-2 sequential processing, KABC-2 planning/reasoning, and BOT-2 motor proficiency.

CONCLUSIONS

Significant motor and cognitive deficits were found in HIV-infected ART-naive Ugandan children with CD4 cell counts of ∼350 cells/μL and percentages of >15%. Study of whether early initiation of ART could prevent or reverse such deficits is needed.

The kynurenine pathway and quinolinic acid: pivotal roles in HIV associated neurocognitive disorders

This brief review will first consider HIV associated neurocognitive disorder followed by the current understanding of its neuropathogenesis. Against this background the role of the kynurenine pathway will be detailed. Evidence both direct and indirect will be discussed for involvement of the kynurenine pathway at each step in the neuropathogenesis of HIV associated neurocognitive disorder.