Kevin R. Robertson

The prevalence and incidence of neurocognitive impairment in the HAART era.

Objectives:HAART suppresses HIV viral replication and restores immune function. The effects of HAART on neurological disease are less well understood. The aim of this study was to assess the prevalence and incidence of neurocognitive impairment in individuals who initiated HAART as part of an AIDS clinical trial. Design:A prospective cohort study of HIV-positive patients enrolled in randomized antiretroviral trials, the AIDS Clinical Trials Group (ACTG) Longitudinal Linked Randomized Trials (ALLRT) study. Methods:We examined the association between baseline and demographic characteristics and neurocognitive impairment among 1160 subjects enrolled in the ALLRT study. Results:A history of immunosuppression (nadir CD4 cell count < 200 cells/μl) was associated with an increase in prevalent neurocognitive impairment. There were no significant virological and immunological predictors of incident neurocognitive impairment. Current immune status (low CD4 cell count) was associated with sustained prevalent impairment. Conclusion:The association of previous advanced immunosuppression with prevalent and sustained impairment suggests that there is a non-reversible component of neural injury that tracks with a history of disease progression. The association of sustained impairment with worse current immune status (low CD4 cell count) suggests that restoring immunocompetence increases the likelihood of neurocognitive recovery. Finally, the lack of association between incident neurocognitive impairment and virological and immunological indicators implies that neural injury continues in some patients regardless of the success of antiretroviral therapy on these laboratory measures.

Impact of Combination Antiretroviral Therapy on Cerebrospinal Fluid HIV RNA and Neurocognitive Performance

Objective:To determine whether antiretroviral regimens with good central nervous system (CNS) penetration control HIV in cerebrospinal fluid (CSF) and improve cognition. Design:Multisite longitudinal observational study. Setting:Research clinics. Study participants:One hundred and one individuals with advanced HIV beginning or changing a new potent antiretroviral regimen were enrolled in the study. Data for 79 participants were analyzed. Participants underwent structured history and neurological examination, venipuncture, lumbar puncture, and neuropsychological tests at entry, 24, and 52 weeks. Intervention:Antiretroviral regimens were categorized as CNS penetration effectiveness (CPE) rank of at least 2 or less than 2. Generalized estimating equations were used to examine associations over the course of the study. Main outcome measures:Concentration of HIV RNA in CSF and blood and neuropsychological test scores (NPZ4 and NPZ8). Results:Odds of suppression of CSF HIV RNA were higher when CPE rank was at least 2 than when it was less than 2. Odds of suppression of plasma HIV RNA were not associated with CPE rank. Among participants with impaired neuropsychological performance at entry, those prescribed regimens with a CPE rank of at least 2 or more antiretrovirals had lower composite NPZ4 scores over the course of the study. Conclusion:Antiretroviral regimens with good CNS penetration, as assessed by CPE rank, are more effective in controlling CSF (and presumably CNS) viral replication than regimens with poorer penetration. In this study, antiretrovirals with good CNS penetration were associated with poorer neurocognitive performance. A larger controlled trial is required before any conclusions regarding the influence of specific antiretrovirals on neurocognitive performance should be made.

HIV-infected subjects with the E4 allele for APOE have excess dementia and peripheral neuropathy

HIV produces a chronic viral infection of the central nervous system that elicits chronic glial activation and overexpression of glial cytokines1–5 that are also implicated in Alzheimer disease (AD) pathogenesis6–11. A genetic risk factor for AD is the E4 isoform for apolipoprotein E (APOE)12,13. Here we compare the frequency of neurologic symptoms for subjects with and without the E4 isoform (E4(+)and E4(–), respectively) in an HIV cohort14–17. Compared with E4(–) subjects, twice as many E4(+) subjects were demented (30% compared with 15%) or had peripheral neuropathy (70% compared with 39%) at least once, and they had threefold more symptomatic examinations (13% compared with 3% and 42% compared with 14%, respectively)(P < 0.0001). Thus, neurologic symptoms for HIV-infection and AD are linked through an etiologic risk factor. Long-term survivors of HIV infection with E4 may be at high risk for AD; conversely, gene–viral interactions may speed AD pathogenesis.

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

Objective:Differences in antiretroviral distribution into the central nervous system (CNS) may impact neurocognitive status. We assessed the relationship between estimates of antiretroviral therapy penetration into the CNS, using a published ranking system, and neurocognitive status in HIV-positive participants with plasma HIV-1 RNA (vRNA) suppression. Design:Participants with at least 6 weeks ongoing antiretroviral drug use and vRNA less than 50 copies/ml (N = 2636; 83% male, median baseline CD4 T cells: 244 cells/μl) had at least one neuroscreen assessment [Trail Making Test, Part A and B; Wechsler Adult Intelligence Scale-Revised (WAIS-R) Digit Symbol] at 10 413 neurovisits. Neuroscreen test scores were demographically adjusted and converted to Z-scores (NPZ3: lower scores imply more impairment). Central nervous system penetration effectiveness (CPE) ranks of 0.0 (low), 0.5 (medium), or 1.0 (high) were assigned to antiretrovirals and summed per regimen, per neurovisit. Methods:Multivariate linear regression models using generalized estimating equations assessed NPZ3 scores with respect to antiretroviral regimen. Covariates were retained if P ≤ 0.1. Results:A final model demonstrated that better NPZ3 scores were associated with higher CPE among participants taking more than three antiretroviral drugs (+0.07 per one unit increase in CPE score; P = 0.004) but not among participants with three or less antiretroviral drugs in the regimen (+0.01; P = 0.5). Results were adjusted for demographics, injection drug use, hepatitis C virus serostatus, CD4 cell count (current and nadir), baseline vRNA, antiretroviral experience, and years since first antiretroviral drug use. Conclusion:Use of antiretroviral drugs with better estimated CNS penetration may be associated with better neurocognitive functioning; some people may require more than three antiretroviral drugs to treat HIV in the CNS. Clinically this means antiretroviral regimens could be designed to optimize estimated CNS penetration without sacrificing virologic and immunologic benefits.

HIV in body fluids during primary HIV infection: Implications for pathogenesis, treatment and public health

ObjectiveTo describe initial viral dissemination to peripheral tissues and infectious body fluids during human primary HIV infection. DesignObservational cohort study. MethodsBlood plasma, cerebrospinal fluid (CSF), seminal plasma, cervicovaginal lavage fluid and/or saliva were sampled from 17 individuals with primary HIV infection (range of time from symptoms onset to sampling, 8–70 days) and one individual with early infection (168 days). Subjects’ HIV-1 RNA levels in each fluid were compared with levels from antiretroviral-naive controls with established HIV infection. For study subjects, correlations were assessed between HIV-1 RNA levels and time from symptoms onset. Responses to antiretroviral therapy with didanosine + stavudine + nevirapine ± hydroxyurea were assessed in each compartment. ResultsHIV-1 RNA levels were highest closest to symptoms gnset in blood plasma (18 patients) and saliva (11 patients). CSF HIV-1 RNA levels (five patients) appeared lower closer to symptoms onset, although they were higher overall in primary versus established infection. Shedding into seminal plasma (eight patients) and cervicovaginal fluid (two patients) was established at levels observed in chrgnic infection within 3–5 weeks of symptoms onset. High-level seminal plasma shedding was associated with coinfection with other sexually transmitted pathogens. Virus replication was suppressed in all compartments by antiretroviral therapy. ConclusionsPeak level HIV replication is established in blood, oropharyngeal tissues and genital tract, but potentially not in CSF, by the time patients are commonly diagnosed with primary HIV infection. Antiretroviral therapy is unlikely to limit initial virus spread to most tissue compartments, but may control genital tract shedding and central nervous system expansiof in primary infection.

HIV-1 expression within resting CD4+ T cells after multiple doses of vorinostat.

BACKGROUND A single dose of the histone deacetylase inhibitor vorinostat (VOR) up-regulates HIV RNA expression within resting CD4(+) T cells of treated, aviremic human immunodeficiency virus (HIV)-positive participants. The ability of multiple exposures to VOR to repeatedly disrupt latency has not been directly measured, to our knowledge. METHODS Five participants in whom resting CD4(+) T-cell-associated HIV RNA (rc-RNA) increased after a single dose of VOR agreed to receive daily VOR Monday through Wednesday for 8 weekly cycles. VOR serum levels, peripheral blood mononuclear cell histone acetylation, plasma HIV RNA single-copy assays, rc-RNA, total cellular HIV DNA, and quantitative viral outgrowth assays from resting CD4(+) T cells were assayed. RESULTS VOR was well tolerated, with exposures within expected parameters. However, rc-RNA measured after dose 11 (second dose of cycle 4) or dose 22 (second dose of cycle 8) increased significantly in only 3 of the 5 participants, and the magnitude of the rc-RNA increase was much reduced compared with that after a single dose. Changes in histone acetylation were blunted. Results of quantitative viral outgrowth and other assays were unchanged. CONCLUSIONS Although HIV latency is disrupted by an initial VOR dose, the effect of subsequent doses in this protocol was much reduced. We hypothesize that the global effect of VOR results in a refractory period of ≥ 24 hours. The optimal schedule for VOR administration is still to be defined.

Neurocognitive effects of treatment interruption in stable HIV-positive patients in an observational cohort.

Objective: Prior studies have shown improved neurocognition with initiation of antiretroviral treatment (ART) in HIV. We hypothesized that stopping ART would be associated with poorer neurocognitive function. Methods: Neurocognitive function was assessed as part of ACTG 5170, a multicenter, prospective observational study of HIV-infected subjects who elected to discontinue ART. Eligible subjects had CD4 count >350 cells/mm3, had HIV RNA viral load <55,000 cp/mL, and were on ART (≥2 drugs) for ≥6 months. Subjects stopped ART at study entry and were followed for 96 weeks with a neurocognitive examination. Results: A total of 167 subjects enrolled with a median nadir CD4 of 436 cells/mm3 and 4.5 median years on ART. Significant improvements in mean neuropsychological scores of 0.22, 0.39, 0.53, and 0.74 were found at weeks 24, 48, 72, and 96 (all p < 0.001). In the 46 subjects who restarted ART prior to week 96, no significant changes in neurocognitive function were observed. Conclusion: Subjects with preserved immune function found that neurocognition improved significantly following antiretroviral treatment (ART) discontinuation. The balance between the neurocognitive cost of untreated HIV viremia and the possible toxicities of ART require consideration. Classification of evidence: This study provides Class III evidence that discontinuing ART is associated with an improvement in 2 neuropsychological tests (Trail-Making Test A & B and the Wechsler Adult Intelligence Scale–Revised Digit Symbol subtest) for up to 96 weeks. Resuming ART was not associated with a decline in these scores for up to 45 weeks.

Childhood history of abuse and adult child abuse potential

The experience of aversive interactions within the family of origin is believed to increase the probability of parental physical child abuse. To test this hypothesis, 375 subjects were given a Childhood History Questionnaire (CHQ) and the Child Abuse Potential (CAP) Inventory. The CHQ contained a series of questions about the presence and frequency of various abusive behaviors and associated sequelae that were received and/or observed before and/or after puberty. The CAP Inventory was used to measure adult physical child abuse potential. As expected, a childhood history of physical abuse was significantly related to adult physical child abuse potential; and, as chronicity increased, so did abuse potential. The experience of physical abuse prior to puberty produced higher abuse scores than the experience of physical abuse after puberty. The study provides preliminary data indicating the childhood experience of a caring adult and / or caring friend moderates adult child abuse potential.

Highly active antiretroviral therapy improves neurocognitive functioning

Summary:Although the effects of highly active antiretroviral therapy (HAART) have resulted in substantial improvements in the systemic health of patients with HIV infection, concerns remain that these medications, which cross the blood–brain barrier poorly, may have a less beneficial effect on nervous system function. This raises the possibility that there may be a progressive long-term decline in neurologic function in patients with adequate systemic response. In a prospective longitudinal study, subjects were evaluated immediately before instituting HAART. Forty-eight subjects underwent ultrasensitive HIV RNA quantitative evaluation of both plasma and cerebrospinal fluid as well as neurologic and neuropsychological examinations. They were reevaluated 6 months after treatment initiation while receiving stable HAART. Both plasma and cerebrospinal fluid viral levels significantly declined after treatment. There was significant improvement in neurologic and neuropsychological functioning after HAART. These results indicate that despite the poor central nervous system penetration of most of these agents, there is satisfactory short-term improvement in both central nervous system viral burden and nervous system function with HAART. However, because treatment failure is increasingly likely over time, continued longitudinal evaluation of this group of subjects is required.

Antiretroviral therapy improves cognitive impairment in HIV+ individuals in sub-Saharan Africa

Background: Highly active antiretroviral therapy (HAART) can improve cognitive performance in some patients with HIV-associated cognitive impairment in the United States. The effect of HAART on HIV dementia in sub-Saharan Africa is largely unknown. Objective: To evaluate neuropsychological test and functional performance in HIV+ individuals after 3 and 6 months of HAART in Uganda. Methods: Twenty-three HIV+ individuals receiving HAART also received a detailed clinical history, neuropsychological testing, and a functional assessment. Follow-up evaluations were performed at 3 and 6 months after baseline. Longitudinal changes in the HIV dementia stage, the mean Z score for each neuropsychological test, and the Karnofsky Functional Performance Scale were evaluated at 3 and 6 months. Results: The mean (SD) CD4 cell count improved from 71 (15) at baseline to 161 (30) at 3 months (p = 0.005) and 222 (46) at 6 months (p < 0.001). Improvements were found in the Memorial Sloan Kettering HIV dementia stage and in tests of verbal memory, psychomotor speed, and executive functioning after 3 and 6 months of HAART (p < 0.001 at 6 months for each neuropsychological test). There was also improvement in the Karnofsky Functional Performance Scale at both 3 and 6 months after the initiation of HAART (p < 0.001). Conclusion: Highly active antiretroviral therapy (HAART) can be associated with improvement in neurocognitive and functional performance in HIV+ individuals in sub-Saharan Africa. These results suggest that HAART, if available in areas with limited resources in sub-Saharan Africa, should be provided for patients with HIV-associated cognitive impairment.