Differences in the direction of change of cerebral function parameters are evident over three years in HIV-infected individuals electively commencing initial cART

Increased Dolutegravir Peak Concentrations in People Living With Human Immunodeficiency Virus Aged 60 and Over, and Analysis of Sleep Quality and Cognition

Background

Demographic data show an increasingly aging human immunodeficiency virus (HIV) population worldwide. Recent concerns over dolutegravir-related neuropsychiatric toxicity have emerged, particularly amongst older people living with HIV (PLWH). We describe the pharmacokinetics (PK) of dolutegravir (DTG) 50 mg once daily in PLWH aged 60 and older. Additionally, to address calls for prospective neuropsychiatric toxicodynamic data, we evaluated changes in sleep quality and cognitive functioning in this population after switching to abacavir (ABC)/lamivudine (3TC)/DTG over 6 months.

Methods

PLWH ≥60 years with HIV-viral load <50 copies/mL on any non-DTG-based antiretroviral combination were switched to ABC/3TC/DTG. On day 28, 24-hour PK sampling was undertaken. Steady-state PK parameters were compared to a published historical control population aged ≤50 years. We administered 6 validated sleep questionnaires and neurocognitive (Cogstate) testing pre-switch and over 180 days.

Results

In total, 43 participants enrolled, and 40 completed the PK phase. Overall, 5 discontinued (2 due to sleep-related adverse events, 4.6%). DTG maximum concentration (Cmax) was significantly higher in patients ≥60 years old versus controls (geometric mean 4246 ng/mL versus 3402 ng/mL, P = .005). In those who completed day 180 (n = 38), sleep impairment (Pittsburgh Sleep Quality Index) was marginally higher at day 28 (P = .02), but not at days 90 or 180. Insomnia, daytime functioning, and fatigue test scores did not change statistically over time.

Conclusions

DTG Cmax was significantly higher in older PLWH. Our data provides clinicians with key information on the safety of prescribing DTG in older PLWH.

Neurometabolic Remodeling in Chronic Hiv Infection: a Five-Year Follow-up Multi-Voxel Mrs Study

There is a lack of data about the long-term follow-up changes in neurometabolic profile and neuropsychological performance of HIV-positive subjects under continuous antiretroviral therapy (cART). The aim of the study was to assess changes in neurometabolic profile in chronically-infected, HIV-positive subjects during a five-year follow-up period, using multi-voxel proton magnetic resonance spectroscopy (¹H-MRS). Nineteen neurologically asymptomatic, aviremic, HIV-positive subjects, underwent multi-voxel 2D MRS on a 3 T MR unit and synchronous neurocognitive assessment in a five-year follow-up period. Twelve voxels were placed in prefrontal cortices, anterior and posterior cingulate gyrus, intraparietal sulci, and frontal centrum semiovale white matter, to identify peaks of N-acetyl-aspartate (NAA), creatine (Cr), choline (Cho), and myoinositol (mI). Ratios of NAA/Cr, NAA/Cho, NAA/mI, mI/Cr, and Cho/Cr were analyzed. Longitudinal differences in ratios and neurocognitive scores were tested with the Wilcoxon signed-rank-test. Statistical significance was set at p ≤ 0.004 significant, and 0.05 > p > 0.004 trending toward significance. A significant longitudinal increase in NAA/Cr ratio was observed in 5/12 voxels, while there was a trend toward significance in an additional three. The increase in Cho/Cr reached statistical significance in one voxel. Changes in the mI/Cr ratio demonstrated a significant increase in 4/12 voxels. A progressive increase in NAA/Cr, followed by better neurocognitive performance, may be an indicator of brain plasticity in the setting of chronic HIV-related neuronal injury. A progressive mI/Cr increase could be partly explained by glial proliferation due to functional compartment remodeling and partly attributable to insufficient control of persistent neuroinflammation by cART.

Heterogeneity in neurocognitive change trajectories among people with HIV starting antiretroviral therapy in Rakai, Uganda

Considerable heterogeneity exists in patterns of neurocognitive change in people with HIV (PWH). We examined heterogeneity in neurocognitive change trajectories from HIV diagnosis to 1-2 years post-antiretroviral therapy (ART). In an observational cohort study in Rakai, Uganda, 312 PWH completed a neuropsychological (NP) test battery at two-time points (ART-naïve, 1-2 years post-ART initiation). All NP outcomes were used in a latent profile analysis to identify subgroups of PWH with similar ART-related neurocognitive change profiles. In a subset, we examined subgroup differences pre-ART on cytokine and neurodegenerative biomarkers CSF levels. We identified four ART-related change subgroups: (1) decline-only (learning, memory, fluency, processing speed, and attention measures), (2) mixed (improvements in learning and memory but declines in attention and executive function measures), (3) no-change, or (4) improvement-only (learning, memory, and attention measures). ART-related NP outcomes that are most likely to change included learning, memory, and attention. Motor function measures were unchanged. Subgroups differed on eight of 34 pre-ART biomarker levels including interleukin (IL)-1β, IL-6, IL-13, interferon-γ, macrophage inflammatory protein-1β, matrix metalloproteinase (MMP)-3, MMP-10, and platelet-derived growth factor-AA. The improvement-only and mixed subgroups showed lower levels on these markers versus the no-change subgroup. These findings provide support for the need to disentangle heterogeneity in ART-related neurocognitive changes, to focus on higher-order cognitive processes (learning, memory, attention) as they were most malleable to change, and to better understand why motor function remained unchanged despite ART treatment. Group differences in pre-ART CSF levels provide preliminary evidence of biological plausibility of neurocognitive phenotyping.

CNS-Targeted Antiretroviral Strategies: When Are They Needed and What to Choose

PURPOSE OF REVIEW

Neurocognitive disorders are not uncommon in HIV-positive patients but their pathogenesis is multifactorial and incompletely understood. After excluding contributing comorbidities, several factors may impair neurocognition including severe immune suppression, incomplete antiviral efficacy, drugs' persistent immune activation, vascular abnormalities, and drugs' neurotoxicity. The effectiveness of targeted antiretroviral strategies on these risk factors is unknown.

RECENT FINDINGS

Recent studies support the idea that residual cerebrospinal fluid HIV RNA in the setting of plasma viral suppression is associated with compartmental immune activation but the link to neuronal damage is debated. Some authors have reported an incomplete antiviral efficacy in macrophage-derived cells but targeted antiretroviral regimen switches have not been performed. Additionally, improvements in neurocognition using drugs with better central nervous system penetration or maraviroc (associated with favorable immunological properties) have been observed in pilot studies. Trials evaluating specific interventions for cardiovascular health (including brain white matter abnormalities) and neurotoxicity of antiretrovirals are warranted. Central nervous system-targeted antiretroviral strategies are needed in patients with uncontrolled cerebrospinal HIV replication, and they may be suggested in subjects with low CD4 nadir, individuals carrying drug-resistant viruses, and those with compartmental immune activation.

HIV infection and latency induce a unique metabolic signature in human macrophages

Currently, a major barrier to curing HIV infection is the generation of tissue-associated, non-replicating, long-lasting viral reservoirs that are refractory to therapy and can be reactivated upon anti-retroviral therapy interruption. One of these reservoirs are latently HIV-infected macrophages. Here, we show that HIV infection of macrophages results in survival of a small population of infected cells that are metabolically altered and characterized by mitochondrial fusion, lipid accumulation, and reduced mitochondrial ATP production. No changes in glycolysis were detected. Metabolic analysis indicated an essential role of succinate and other TCA metabolites in the tricarboxylic acid (TCA) cycle in mediating lipid accumulation and oxidative phosphorylation (OXPHOS) in the mitochondria. Furthermore, we show that while uninfected and HIV infected macrophages use fatty acids and glucose as primary sources of energy, surviving HIV infected macrophages also use glutamine/glutamate as a major energy source, and blocking these new sources of energy resulted in the killing of latent HIV infected macrophages. Together, our data provide a new understanding of the formation, properties, and potential novel ways to eliminate macrophage viral reservoirs.

White matter microstructure among perinatally HIV-infected youth: a diffusion tensor imaging study

We evaluated white matter microstructure integrity in perinatally HIV-infected (PHIV) youths receiving cART compared to age- and gender-matched healthy youths through DTI metrics using voxel-based morphometry (VBM). We investigated 14 perinatally HIV-infected patients (age 17.9 ± 2.5 years) on cART and 17 healthy youths (HC) (age 18.0 ± 3.0 years) using a 3T MRI scanner. Four DTI-derived metrics were fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Statistical analysis was done with voxel-based analysis of covariance (ANCOVA), with age and gender as covariates. Region-of-interest secondary analyses in statistically significant regions were also performed. Regional increases in FA in the PHIV youths were found in left middle frontal gyrus, right precuneus, right lingual gyrus, and left supramarginal gyrus. Increased MD was found in the right precentral gyrus while decreased MD was found in the white matter of the right superior parietal lobule and right inferior temporal gyrus/fusiform gyrus. Regions of increased/decreased RD overlapped with regions of increased/decreased MD. Both increased and decreased AD were found in three to four regions respectively. The regional FA, MD, RD, and AD values were consistent with the voxel-based analysis findings. The findings are mostly consistent with previous literature, but increased FA has not been previously reported for perinatally HIV-infected youths. Potentially early and prolonged therapy in our population may have contributed to this new finding. Both toxicity of antiretroviral therapy and indolent infection must be considered as causative factors in the DTI metric changes that we have observed.

Similar neurocognitive outcomes after 48 weeks in HIV-1-infected participants randomized to continue tenofovir/emtricitabine + atazanavir/ritonavir or simplify to abacavir/lamivudine + atazanavir

Human immunodeficiency virus (HIV)-associated neurocognitive disorders can persist in many patients despite achieving viral suppression while on antiretroviral therapy (ART). Neurocognitive function over 48 weeks was evaluated using a Cogstate test battery assessing psychomotor function, attention, learning, and working memory in 293 HIV-1-infected, ART-experienced, and virologically suppressed adults. The ASSURE study randomized participants 1:2 to remain on tenofovir/emtricitabine (TDF/FTC) and ritonavir-boosted atazanavir (ATV/r) or simplify to abacavir/lamivudine + atazanavir (ABC/3TC + ATV). Neurocognitive z-scores were computed using demographically adjusted normative data and were classified as "impaired" (defined as either a z-score ≤ - 2 or having 2 or more standardized individual test z-scores ≤ - 1); while higher scores (equaling better performance) were classified as "normal". By z-scores, 54.7% of participants had impaired neurocognition at baseline and 50.2% at week 48. There were no significant differences (p < 0.05) in the baseline-adjusted performance between treatment groups for any individual test or by z-score. Specific demographic and medical risk factors were evaluated by univariate analysis for impact on neurocognitive performance. Factors with p < 0.10 were evaluated by backwards regression analysis to identify neurocognition-correlated factors after accounting for treatment, assessment, and baseline. Four risk factors at baseline for impaired neurocognition were initially identified: lower CD4 nadir lymphocyte counts, higher Framingham risk scores, and interleukin-6 levels, and a history of psychiatric disorder not otherwise specified, however none were found to moderate the effect of treatment on neurocognition. In this aviremic, treatment-experienced population, baseline-adjusted neurocognitive function remained stable and equivalent over 48 weeks with both TDF/FTC + ATV/r-treated and in the ART-simplified ABC/3TC + ATV treatment groups.

White matter measures are near normal in controlled HIV infection except in those with cognitive impairment and longer HIV duration

The objective of the current study was to quantify the degree of white matter (WM) abnormalities in chronic and virally suppressed HIV-infected (HIV+) persons while carefully taking into account demographic and disease factors. Diffusion tensor imaging (DTI) was conducted in 40 HIV- and 82 HIV+ men with comparable demographics and life style factors. The HIV+ sample was clinically stable with successful viral control. Diffusion was measured across 32 non-colinear directions with a b-value of 1000 s/mm²; fractional anisotropy (FA) and mean diffusivity (MD) maps were quantified with Itrack IDL. Using the ENIGMA DTI protocol, FA and MD values were extracted for each participant and in 11 skeleton regions of interest (SROI) from standard labels in the JHU ICBM-81 atlas covering major striato-frontal and parietal tracks. We found no major differences in FA and MD values across the 11 SROI between study groups. Within the HIV+ sample, we found that a higher CNS penetrating antiretroviral treatment, higher current CD4+ T cell count, and immune recovery from the nadir CD4+ T cell count were associated with increased FA and decreased MD (p < 0.05-0.006), while HIV duration, symptomatic, and asymptomatic cognitive impairment were associated with decreased FA and increased MD (p < 0.01-0.004). Stability of HIV treatment and antiretroviral CNS penetration efficiency in addition to current and historical immune recovery were related to higher FA and lower MD (p = 0.04-p < 0.01). In conclusion, WM DTI measures are near normal except for patients with neurocognitive impairment and longer HIV disease duration.

Pilot Assessment of Brain Metabolism in Perinatally HIV-Infected Youths Using Accelerated 5D Echo Planar J-Resolved Spectroscopic Imaging

Purpose

To measure cerebral metabolite levels in perinatally HIV-infected youths and healthy controls using the accelerated five dimensional (5D) echo planar J-resolved spectroscopic imaging (EP-JRESI) sequence, which is capable of obtaining two dimensional (2D) J-resolved spectra from three spatial dimensions (3D).

Materials and Methods

After acquisition and reconstruction of the 5D EP-JRESI data, T₁-weighted MRIs were used to classify brain regions of interest for HIV patients and healthy controls: right frontal white (FW), medial frontal gray (FG), right basal ganglia (BG), right occipital white (OW), and medial occipital gray (OG). From these locations, respective J-resolved and TE-averaged spectra were extracted and fit using two different quantitation methods. The J-resolved spectra were fit using prior knowledge fitting (ProFit) while the TE-averaged spectra were fit using the advanced method for accurate robust and efficient spectral fitting (AMARES).

Results

Quantitation of the 5D EP-JRESI data using the ProFit algorithm yielded significant metabolic differences in two spatial locations of the perinatally HIV-infected youths compared to controls: elevated NAA/(Cr+Ch) in the FW and elevated Asp/(Cr+Ch) in the BG. Using the TE-averaged data quantified by AMARES, an increase of Glu/(Cr+Ch) was shown in the FW region. A strong negative correlation (r < -0.6) was shown between tCh/(Cr+Ch) quantified using ProFit in the FW and CD4 counts. Also, strong positive correlations (r > 0.6) were shown between Asp/(Cr+Ch) and CD4 counts in the FG and BG.

Conclusion

The complimentary results using ProFit fitting of J-resolved spectra and AMARES fitting of TE-averaged spectra, which are a subset of the 5D EP-JRESI acquisition, demonstrate an abnormal energy metabolism in the brains of perinatally HIV-infected youths. This may be a result of the HIV pathology and long-term combinational anti-retroviral therapy (cART). Further studies of larger perinatally HIV-infected cohorts are necessary to confirm these findings.

Evolution of changes in cognitive function after the initiation of antiretroviral therapy

BACKGROUND

Cognitive function is reported to improve after the initiation of combination antiretroviral therapy (cART). Data on the evolution of such changes are limited. We assessed the dynamics of changes in cognitive parameters, in HIV-positive subjects initiating cART.

METHODS

Cognitive function in seven domains was evaluated for HIV-infected patients without clinically significant cognitive impairment prior to the initiation of cART, and 24 and 48 weeks after. Cognitive scores were transformed using standardised z-scores according to the pooled baseline standard deviation. Global, speed, and accuracy composite z-scores were calculated with changes calculated using a paired t test.

RESULTS

In 14 subjects, change in global cognitive z-scores from baseline was by 0.08 at week 24 (p = 0.59) and 0.15 at week 48 (p = 0.43). Change in composite speed and accuracy z-scores from baseline at weeks 24/48 were 0.07/0.05 (p = 0.45/0.82) and 0.13/0.23 (p = 0.47/0.45), respectively. In two of the cognitive domains assessing speed (learning and monitoring time), a continued improvement from baseline to weeks 24 and 48 was observed (changes of 0.06-0.08 and 0.10-0.19, respectively), whereas in two domains (detection and identification) an initial improvement at week 24 (changes of -0.10 and 0.04 from baseline, respectively) was followed by a deterioration in score at week 48 (changes of -0.12 and -0.08 from baseline, respectively). None of these changes were statistically significant.

CONCLUSIONS

A trend for improvement in cognitive function was observed in naïve HIV-positive patients starting cART. The dynamics of this improvement differed both between cognitive domains and the time-points assessed.