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Synaptic plasticity is obstructed by pathogenic tau in the brain, representing a key mechanism that underlies memory loss in Alzheimer’s disease (AD) and related tauopathies. Here, we define a mechanism for plasticity repair in vulnerable neurons using the C-terminus of the KIdney/BRAin (KIBRA) protein (CT-KIBRA). We show that CT-KIBRA restores plasticity and memory in transgenic mice expressing pathogenic human tau; however, CT-KIBRA did not alter tau levels or prevent tau-induced synapse loss. Instead, we find that CT-KIBRA binds to and stabilizes protein kinase Mζ (PKMζ) to maintain synaptic plasticity and memory despite tau mediated pathogenesis. In humans we find that reduced KIBRA in brain and increased KIBRA in cerebrospinal fluid are associated with cognitive impairment and pathological tau levels in disease. Thus, our results distinguish KIBRA both as a novel biomarker of synapse dysfunction in AD and as the foundation for a synapse repair mechanism to reverse cognitive impairment in tauopathy.

ObjectiveChronic inflammation and vascular dysfunction (e.g., chronic endothelial activation) are related yet dissociable mechanisms of HIV-associated neurocognitive impairment (NCI), even among those on antiretroviral therapy (ART). However, how these mechanisms differentially contribute to domain-specific deficits in people with and without HIV (PWH, PWoH) is unclear. We empirically-derived profiles of NCI and examined relationships with peripheral inflammatory and vascular biomarkers.MethodsParticipants were 84 virally-suppressed PWH and 126 PWoH who underwent neuropsychological testing and blood draw. Cluster analysis identified subgroups based on domain deficit scores. ANOVAs examined HIV serostatus and cluster group differences in composite plasma biomarker z-scores of inflammation (IL-6, CXCL10/IP-10, CCL2/MCP-1) and vascular injury (VCAM-1, ICAM-1, uPAR). Confirmatory regressions examined the interaction of HIV and biomarker z-scores on domain-specific T-scores, controlling for cardiovascular disease (CVD) risk and psychosocial factors.ResultsCluster analysis identified three groups: Unimpaired (n=129), Learning/Recall (n=52, isolated learning/recall deficits), Dysexecutive/Slow (n=29, executive function, working memory, processing speed, and motor deficits). PWH had higher odds of Dysexecutive/Slow membership, which related to CVD risk and higher vascular dysfunction, but not inflammation, in PWH. Vascular biomarkers moderated adverse HIV effects on executive function, processing speed, and working memory such that PWH had lower T-scores only when vascular dysfunction was high.ConclusionsIn PWH with controlled disease, peripheral markers of endothelial dysfunction and vascular permeability are selectively associated with an empirically-derived subgroup that exhibits domain deficits commonly impacted by cerebrovascular disease. Findings support the presence of a vascular NCI subgroup of PWH who may benefit from interventions that directly target the neurovascular unit.

BackgroundTo investigate joint contributions of cognitive and physiologic reserve to neurocognitive SuperAging in older persons with HIV (PWH).MethodsParticipants included 396 older PWH (age range: 50-69 years) who completed cross-sectional neuropsychological and neuromedical evaluations. Using published criteria, participants exhibiting global neurocognition within normative expectations of healthy 25-year-olds were classified as SuperAgers (SA; n = 57). Cognitively normal (CN; n = 172) and impaired (n = 167) participants were classified with chronological age-based norms. Cognitive reserve was operationalized with an estimate of premorbid verbal intelligence, and physiologic reserve was operationalized with a cumulative index of 39 general and HIV-specific health variables. Analysis of variance with confirmatory multinomial logistic regression examined linear and quadratic effects of cognitive and physiologic reserve on SA status, adjusting for chronological age, depression, and race/ethnicity.ResultsUnivariably, SA exhibited significantly higher cognitive and physiologic reserve compared with CN and cognitively impaired ( d s ≥ 0.38, p s < 0.05). Both reserve factors independently predicted SA status in multinomial logistic regression; higher physiologic reserve predicted linear increases in odds of SA, and higher cognitive reserve predicted a quadratic "J-shaped" change in odds of SA compared with CN (ie, odds of SA > CN only above 35th percentile of cognitive reserve).ConclusionsEach reserve factor uniquely related to SA status, which supports the construct validity of our SA criteria and suggests cognitive and physiologic reserve reflect nonoverlapping pathways of neuroprotection in HIV. Incorporation of proxy markers of reserve in clinical practice may improve characterization of age-related cognitive risk and resilience among older PWH, even among PWH without overt neurocognitive impairment.

Despite the neurocognitive risks of aging with HIV, initial cross-sectional data suggest a subpopulation of older people with HIV (PWH) possess youthful neurocognition (NC) characteristic of SuperAgers (SA). Here we characterize longitudinal NC trajectories of older PWH and their convergent validity with baseline SA status, per established SuperAging criteria in PWH, and baseline biopsychosocial factors. Growth mixture modeling (GMM) identified longitudinal NC classes in 184 older (age ≥ 50-years) PWH with 1-5years of follow-up. Classes were defined using 'peak-age' global T-scores, which compare performance to a normative sample of 25-year-olds. 3-classes were identified: Class 1Stable Elite (n = 31 [16.8%], high baseline peak-age T-scores with flat trajectory); Class 2Quadratic Average (n = 100 [54.3%], intermediate baseline peak-age T-scores with u-shaped trajectory); Class 3Quadratic Low (n = 53 [28.8%], low baseline peak-age T-scores with u-shaped trajectory). Baseline predictors of Class 1Stable Elite included SA status, younger age, higher cognitive and physiologic reserve, and fewer subjective cognitive difficulties. This GMM analysis supports the construct validity of SuperAging in older PWH through identification of a subgroup with longitudinally-stable, youthful neurocognition and robust biopsychosocial health.

HIV and major depressive disorder (MDD) commonly co-occur and are both linked to greater risk-taking behavior, possibly due to neurocognitive impairment (NCI). The present study examined the concordance of the Balloon Analog Risk Task (BART), a gold standard measure of risk-taking propensity, with NCI and real-world sexual risk behaviors in PWH with comorbid MDD. Participants included 259 adults, stratified by HIV serostatus (HIV + /HIV -) and lifetime MDD (MDD + /MDD -), who completed neuropsychological testing, the BART, and sexual risk behavior questionnaires. Logistic regression, stratified by HIV serostatus, examined joint effects of MDD and BART (linear and quadratic) on NCI. Follow-up linear regressions examined sexual risk behavior and neurocognitive domain T-scores as correlates of the BART. NCI prevalence was lowest in HIV - /MDD - , but BART scores did not differ by HIV/MDD status. In the HIV + group, BART performance predicted NCI such that high and low BART scores related to greater odds of NCI, but only in dual-risk HIV + /MDD + individuals. HIV + /MDD + individuals with both low and high BART scores exhibited poorer learning and recall, whereas processing speed and executive function were only poor in low BART risk-taking HIV + /MDD + . Higher BART scores linearly related to higher sexual risk behaviors only in MDD + individuals, independent of HIV serostatus. Low and high risk-taking on the BART may reflect discrete neurocognitive profiles in HIV + /MDD + individuals, with differential implications for real-world sexual risk behavior. HIV and comorbid MDD may disturb corticostriatal circuits responsible for integrating affective and neurocognitive components of decision-making, thereby contributing to risk-averse and risk-taking phenotypes.

ObjectivesGiven the rising number of older people with HIV (PWH) and the overlap in cognitive dysfunction profiles in HIV-associated neurocognitive disorders (HAND) and Alzheimer's disease and its precursor, amnestic mild cognitive impairment (aMCI), methods are needed to distinguish aMCI/Alzheimer's disease from HAND. As an early indicator of Alzheimer's disease, we examined whether olfactory dysfunction could help to distinguish between aMCI/Alzheimer's disease and HAND among PWH.DesignAn observational cohort study.MethodsEighty-one older (≥50 years) PWH (83% men, 65% white) from the California NeuroAIDS Tissue Consortium completed the University of Pennsylvania Smell Identification Test (UPSIT; higher scores = better smell identification) and a comprehensive seven-domain neuropsychological test battery and neuromedical evaluation. HAND was classified via Frascati criteria. High aMCI risk was defined as impairment (>1.0 SD below normative mean) on two of four delayed recall or recognition outcomes (at least one recognition impairment required) from the Hopkins Verbal Learning Test-Revised and the Brief Visuospatial Memory Test-Revised. We examined UPSIT scores in relation to aMCI risk and HAND status, and continuous memory scores considering adjustments for demographics and relevant clinical or HIV disease characteristics.ResultsFifty-seven participants were classified with HAND (70%) and 35 participants were classified as high aMCI risk (43%). UPSIT scores were lower (worse) in the high versus low aMCI risk group [F (1,76) = 10.04, P = 0.002], but did not differ by HAND status [F (1,76) = 0.62, P = 0.43]. UPSIT scores positively correlated with all memory outcomes (Ps

ObjectiveFrascati international research criteria for HIV-associated neurocognitive disorders (HAND) are controversial; some investigators have argued that Frascati criteria are too liberal, resulting in a high false positive rate. Meyer et al. recommended more conservative revisions to HAND criteria, including exploring other commonly used methodologies for neurocognitive impairment (NCI) in HIV including the global deficit score (GDS). This study compares NCI classifications by Frascati, Meyer, and GDS methods, in relation to neuroimaging markers of brain integrity in HIV.MethodTwo hundred forty-one people living with HIV (PLWH) without current substance use disorder or severe (confounding) comorbid conditions underwent comprehensive neurocognitive testing and brain structural magnetic resonance imaging and magnetic resonance spectroscopy. Participants were classified using Frascati criteria versus Meyer criteria: concordant unimpaired [Frascati(Un)/Meyer(Un)], concordant impaired [Frascati(Imp)/Meyer(Imp)], or discordant [Frascati(Imp)/Meyer(Un)] which were impaired via Frascati criteria but unimpaired via Meyer criteria. To investigate the GDS versus Meyer criteria, the same groupings were utilized using GDS criteria instead of Frascati criteria.ResultsWhen examining Frascati versus Meyer criteria, discordant Frascati(Imp)/Meyer(Un) individuals had less cortical gray matter, greater sulcal cerebrospinal fluid volume, and greater evidence of neuroinflammation (i.e., choline) than concordant Frascati(Un)/Meyer(Un) individuals. GDS versus Meyer comparisons indicated that discordant GDS(Imp)/Meyer(Un) individuals had less cortical gray matter and lower levels of energy metabolism (i.e., creatine) than concordant GDS(Un)/Meyer(Un) individuals. In both sets of analyses, the discordant group did not differ from the concordant impaired group on any neuroimaging measure.ConclusionsThe Meyer criteria failed to capture a substantial portion of PLWH with brain abnormalities. These findings support continued use of Frascati or GDS criteria to detect HIV-associated CNS dysfunction.

IntroductionThe Val allele of the Val158Met single-nucleotide polymorphism of the catechol-o-methyltransferase gene (COMT) confers greater catabolism of dopamine (DA) in the prefrontal cortex (PFC) than the Met allele. Met/Met homozygotes typically outperform Val-carriers on tests of executive function (EF), perhaps resulting from increased DA bioavailability. Methamphetamine (METH) causes large releases of DA, which is associated with neurotoxicity and executive dysfunction in chronic METH users. We hypothesized that, contrary to its effect in non-METH-using populations, slower DA clearance conferred by Met/Met will relate to worse EF in METH users.Methods149 non-Hispanic White men, stratified by METH dependence (METH+/-) and COMT (Val/Val, Val/Met, Met/Met), completed three tests of EF: Wisconsin Card Sorting Test (WCST), Stroop Color-Word Test (Stroop), and Trail Making Test Part B (Trails B). Demographically-adjusted test scores were averaged to create an EF composite T-score. We examined the interaction of METH and COMT on the EF composite and individual test T-scores, controlling for premorbid functioning and alcohol use.ResultsMETH group differences in EF were evident only among Met/Met carriers (beta = -9.36, p

HIV and methamphetamine (MA) use disorder are commonly comorbid and individually associated with adverse health consequences, including frailty; however, less is known about the combined effects of both conditions. The current cross-sectional study examined how HIV and lifetime MA use disorder relate to frailty and explored associations between frailty and relevant clinical outcomes (i.e., neurocognitive and everyday functioning). Participants were categorized into three groups based on HIV status and lifetime MA diagnosis: HIV+/MA+ (n = 43), HIV+/MA- (n = 75), and HIV-/MA- (n = 92). A frailty index score (representing proportion of accumulated multisystem deficits) was calculated from 27 medical and psychiatric deficits. Multiple regression was used to examine frailty index score by HIV/MA group. Additional multiple regression models examined the interaction between frailty and HIV/MA group on cognitive and everyday functioning. Comorbid HIV+/MA+ participants had higher frailty index scores than both HIV-/MA- (b = -0.13, p

OBJECTIVES:Methamphetamine (MA) dependence contributes to neurotoxicity and neurocognitive deficits. Although combined alcohol and MA misuse is common, how alcohol consumption relates to neurocognitive performance among MA users remains unclear. We hypothesized that alcohol and MA use would synergistically diminish neurocognitive functioning, such that greater reported alcohol consumption would exert larger negative effects on neurocognition among MA-dependent individuals compared to MA-nonusing persons. METHODS:Eighty-seven MA-dependent (MA+) and 114 MA-nonusing (MA-) adults underwent neuropsychological and substance use assessments. Linear and logistic regressions examined the interaction between MA status and lifetime average drinks per drinking day on demographically corrected global neurocognitive T scores and impairment rates, controlling for recent alcohol use, lifetime cannabis use, WRAT reading performance, and lifetime depression. RESULTS:MA+ displayed moderately higher rates of impairment and lower T scores compared to MA-. Lifetime alcohol use significantly interacted with MA status to predict global impairment (ORR = 0.70, p = .003) such that greater lifetime alcohol use increased likelihood of impairment in MA-, but decreased likelihood of impairment in MA+. Greater lifetime alcohol use predicted poorer global T scores among MA- (b = -0.44, p = .030) but not MA+ (b = 0.08, p = .586). CONCLUSIONS:Contrary to expectations, greater lifetime alcohol use related to reduced risk of neurocognitive impairment among MA users. Findings are supported by prior research identifying neurobiological mechanisms by which alcohol may attenuate stimulant-driven vasoconstriction and brain thermotoxicity. Replication and examination of neurophysiologic mechanisms underlying alcohol use in the context of MA dependence are warranted to elucidate whether alcohol confers a degree of neuroprotection.

OBJECTIVE:The influence of confounding neurocognitive comorbidities in people living with HIV (PLWH) on neuroimaging has not been systematically evaluated. We determined associations between comorbidity burden and brain integrity and examined the moderating effect of age on these relationships. DESIGN:Observational, cross-sectional substudy of the CNS HIV Antiretroviral Therapy Effects Research cohort. METHODS:A total of 288 PLWH (mean age = 44.2) underwent structural MRI and magnetic resonance spectroscopy as well as neurocognitive and neuromedical assessments. Consistent with Frascati criteria for HIV-associated neurocognitive disorders (HAND), neuromedical and neuropsychiatric comorbidity burden was classified as incidental (mild), contributing (moderate), or confounding (severe-exclusionary) to a diagnosis of HAND. Multiple regression modeling predicted neuroimaging outcomes as a function of comorbidity classification, age, and their interaction. RESULTS:Comorbidity classifications were 176 incidental, 77 contributing, and 35 confounded; groups did not differ in HIV disease characteristics. Relative to incidental and contributing participants, confounded participants had less cortical gray matter and more abnormal white matter and ventricular cerebrospinal fluid, alongside more neuroinflammation (choline, myo-inositol) and less neuronal integrity (N-acetylaspartate). Older age exacerbated the impact of comorbidity burden: to a greater extent in the confounded group, older age was associated with more abnormal white matter (P = 0.017), less total white matter (P = 0.015), and less subcortical gray matter (P = 0.014). CONCLUSION:Neuroimaging in PLWH reveals signatures associated with confounding neurocognitive conditions, emphasizing the importance of evaluating these among individuals with suspected HAND. Older age amplifies subcortical and white matter tissue injury, especially in PLWH with severe comorbidity burden, warranting increased attention to this population as it ages.

OBJECTIVES:Studies of neurocognitively elite older adults, termed SuperAgers, have identified clinical predictors and neurobiological indicators of resilience against age-related neurocognitive decline. Despite rising rates of older persons living with HIV (PLWH), SuperAging (SA) in PLWH remains undefined. We aimed to establish neuropsychological criteria for SA in PLWH and examined clinically relevant correlates of SA. METHODS:734 PLWH and 123 HIV-uninfected participants between 50 and 64 years of age underwent neuropsychological and neuromedical evaluations. SA was defined as demographically corrected (i.e., sex, race/ethnicity, education) global neurocognitive performance within normal range for 25-year-olds. Remaining participants were labeled cognitively normal (CN) or impaired (CI) based on actual age. Chi-square and analysis of variance tests examined HIV group differences on neurocognitive status and demographics. Within PLWH, neurocognitive status differences were tested on HIV disease characteristics, medical comorbidities, and everyday functioning. Multinomial logistic regression explored independent predictors of neurocognitive status. RESULTS:Neurocognitive status rates and demographic characteristics differed between PLWH (SA=17%; CN=38%; CI=45%) and HIV-uninfected participants (SA=35%; CN=55%; CI=11%). In PLWH, neurocognitive groups were comparable on demographic and HIV disease characteristics. Younger age, higher verbal IQ, absence of diabetes, fewer depressive symptoms, and lifetime cannabis use disorder increased likelihood of SA. SA reported increased independence in everyday functioning, employment, and health-related quality of life than non-SA. CONCLUSIONS:Despite combined neurological risk of aging and HIV, youthful neurocognitive performance is possible for older PLWH. SA relates to improved real-world functioning and may be better explained by cognitive reserve and maintenance of cardiometabolic and mental health than HIV disease severity. Future research investigating biomarker and lifestyle (e.g., physical activity) correlates of SA may help identify modifiable neuroprotective factors against HIV-related neurobiological aging. (JINS, 2019, 25, 507-519).

AimsOlder persons living with HIV (PLWH) and past alcohol use disorder (AUD) are at higher risk for neurocognitive deficits compared to those with either condition alone; however, factors underlying this relationship are unknown. Given that aging potentiates multi-system damage from alcohol misuse, the current study examined whether neurocognitive functioning among older adults relates to the age at which they last met criteria for AUD (i.e. 'age of last AUD'), and whether this relationship differed by HIV serostatus.MethodsAll participants (aged between 50 and 75 years) were grouped by HIV/AUD status: 345 HIV+/AUD+, 148 HIV-/AUD+, 273 HIV+/AUD-, and 206 HIV-/AUD-. Neurocognitive functioning was assessed globally and within seven domains. Among only the two AUD+ groups, multivariable linear regressions examined the interaction between age of last AUD and HIV status on neurocognitive functioning, controlling for demographics and clinical characteristics.ResultsOlder age of last AUD related to worse processing speed among PLWH (b = -0.03; P = 0.006); however, this relationship was not significant among persons without HIV (b = 0.01; P = 0.455). The interaction between age of last AUD and HIV status did not predict neurocognitive functioning in other domains. Processing speed appeared clinically important, as slower speed related to worse everyday functioning, including more reported cognitive difficulties (r = -0.26, P < 0.001) and higher rates of functional dependence (OR = 0.87, 95%CI = 0.80-0.95, P = 0.002).ConclusionsOur novel findings, demonstrating slower processing speed when a past AUD occurred at an older age in PLWH, highlight the value in assessing older PLWH for processing speed deficits, even if other cognitive domains appear to be intact.

Although cognitive impairment has been well documented in human immunodeficiency virus (HIV) and hepatitis C virus (HCV) mono-infections, research on neurocognitive effects is limited in the context of HIV/HCV co-infection. The aims of this study were to explore the interplay between HIV and HCV infections in the expression of neurocognitive impairment (NCI), and to examine the differences in test performance between HIV/HCV co-infected and HIV or HCV mono-infected patients. A total of 128 participants from Southern Brazil underwent a comprehensive neuropsychological (NP) battery comprising 18 tests. Participants were grouped according to their serological status: HCV mono-infected (n = 20), HIV mono-infected (n = 48), HIV/HCV co-infected (n = 12), and HIV-/HCV-uninfected controls (n = 48). The frequencies of HIV subtypes B and C between the HIV mono-infected and HIV/HCV co-infected groups were comparable. There was greater prevalence of neuropsychological impairment among all three infection groups compared with the uninfected control group, but no statistically significant differences among mono- and co-infected groups were found. HCV infection was associated with cognitive deficits, independently of liver dysfunction. HCV infection did not show an additive effect on neurocognitive function among HIV+. NCI was independent of HCV RNA on peripheral blood, CSF, and hepatic injury. While we did not find additive global effect, in the present study, there was some evidence of additive HIV/HCV co-infection effects in speed of information processing, executive function, and verbal fluency domains when comparing the co-infected group with the other three groups. NP impairment was not dependent on HCV subtypes.