Screening for HIV-related neurocognitive impairment in clinical practice: challenges and opportunities

Neurological soft signs and brain morphology in people living with HIV

Neurological soft signs (NSS) are a common feature of severe psychiatric disorders such as schizophrenia but are also prevalent in organic brain diseases like HIV-associated neurocognitive disorder (HAND) or Alzheimer’s disease. While distinct associations between NSS, neurocognition, and cerebral regions were demonstrated in schizophrenia, these associations still have to be elucidated in HIV. Therefore, we investigated 36 persons with HIV of whom 16 were neurocognitively healthy and 20 were diagnosed with HAND. NSS were assessed using the Heidelberg scale. NSS scores were correlated with gray matter (GM) using whole brain voxel-based morphometry. Results showed significantly elevated NSS in the HAND group when compared to the neurocognitively healthy with respect to NSS total score and the subscores “orientation” and “complex motor tasks”. While the two groups showed only minor, non-significant GM differences, higher NSS scores (subscales “motor coordination”, “orientation”) were significantly correlated with GM reduction in the right insula and cerebellum (FWE-corrected). Our results corroborate elevated NSS in HIV+ patients with HAND in contrast to cognitively unimpaired patients. In addition, cerebral correlates of NSS with GM reductions in insula and cerebellum were revealed. Taken together, NSS in this patient group could be considered a marker of cerebral damage and neurocognitive deficits.

Screening for HIV-Associated Neurocognitive Disorders: Sensitivity and Specificity

HIV-associated neurocognitive disorder (HAND) remains prevalent among people living with HIV (PLWH), especially the mild forms, even those with well-controlled HIV. Recommendations from the literature suggest routine and regular screening for HAND to detect it early and manage it effectively and adjust treatments, if warranted, when present. However, screening for HAND is not routinely done, as there are no current guidelines on when to screen and which test or tests to use. Furthermore, many of the available screening tools for HAND often cannot accurately detect the mild forms of HAND and require highly trained healthcare professionals to administer and score the tests, a requirement that is not feasible for those low- and middle-income countries with the highest HIV incidence and prevalence rates. The purpose of this chapter was to review recent research on screening tests to detect HAND and report on the strengths, limitations, and psychometric properties of those tests to detect HAND.

Global prevalence and burden of HIV-associated neurocognitive disorder

Objective

To characterize the prevalence and burden of HIV-associated neurocognitive disorder (HAND) and assess associated factors in the global population with HIV.

Methods

We searched PubMed and Embase for cross-sectional or cohort studies reporting the prevalence of HAND or its subtypes in HIV-infected adult populations from January 1, 1996, to May 15, 2020, without language restrictions. Two reviewers independently undertook the study selection, data extraction, and quality assessment. We estimated pooled prevalence of HAND by a random effects model and evaluated its overall burden worldwide.

Results

Of 5,588 records identified, we included 123 studies involving 35,513 participants from 32 countries. The overall prevalence of HAND was 42.6% (95% confidence interval [CI] 39.7–45.5) and did not differ with respect to diagnostic criteria used. The prevalence of asymptomatic neurocognitive impairment, mild neurocognitive disorder, and HIV-associated dementia were 23.5% (20.3–26.8), 13.3% (10.6–16.3), and 5.0% (3.5–6.8) according to the Frascati criteria, respectively. The prevalence of HAND was significantly associated with the level of CD4 nadir, with a prevalence of HAND higher in low CD4 nadir groups (mean/median CD4 nadir <200 45.2% [40.5–49.9]) vs the high CD4 nadir group (mean/median CD4 nadir ≥200 37.1% [32.7–41.7]). Worldwide, we estimated that there were roughly 16,145,400 (95% CI 15,046,300–17,244,500) cases of HAND in HIV-infected adults, with 72% in sub-Saharan Africa (11,571,200 cases, 95% CI 9,600,000–13,568,000).

Conclusions

Our findings suggest that people living with HIV have a high burden of HAND in the antiretroviral therapy (ART) era, especially in sub-Saharan Africa and Latin America. Earlier initiation of ART and sustained adherence to maintain a high-level CD4 cell count and prevent severe immunosuppression is likely to reduce the prevalence and severity of HAND.

Screening for HIV-associated neurocognitive disorders in perinatally infected adolescents: youth-International HIV Dementia Scale validation

CONTEXT

Perinatal HIV infection has adverse cognitive consequences into adolescence. However, there are no screening tools that assess risk for HIV-associated neurocognitive disorders in adolescent populations. Such screening tools are needed urgently for clinical care in resource-poor settings with a high prevalence of HIV.

OBJECTIVE

To investigate the performance of the International HIV Dementia Scale (IHDS) as a screening tool for HIV-associated neurocognitive disorders in perinatally adolescents.

DESIGN

The current study is a quantitative, quasiexperimental design.

METHODS

Perinatally HIV-infected adolescents aged 9-12 years were recruited from community health clinics into the Cape Town Adolescent Antiretroviral Cohort; matched HIV-negative controls from the same communities were enrolled. Each participant completed the IHDS and a comprehensive neuropsychological battery. The adult version of the IHDS was performed, except for two minor modifications. We evaluated the diagnostic validity of this modified instrument, the youth-IHDS (y-IHDS), using a four-step process that included sensitivity and specificity calculations, and generating receiver operating characteristic curves. Validity was measured against the youth HIV-associated diagnostic criteria.

RESULTS

At a cut-off score of 10 or less, the y-IHDS demonstrated good sensitivity (94%) but poor specificity (24%) for detecting all forms of neurocognitive disorders, with an acceptable area under the curve value of 0.695.

CONCLUSION

The y-IHDS requires minimal resources and is based on a screening tool for adult HIV-associated cognitive disorders that is already widely used globally. Hence, this brief, cost-efficient, and valid screening tool may be a useful addition for clinicians working in resource-poor contexts in which adolescent HIV is highly prevalent.

Assessing Risk of HIV-Associated Neurocognitive Disorder

BACKGROUND

People with HIV (PLHIV) are aging, and 20% are at risk of developing a neurological complication known as HIV-associated neurocognitive disorder (HAND). Signs and symptoms of HAND may be subtle; however, treatment can improve clinical outcomes.

OBJECTIVE

The aim of the study was to identify and agree on a risk assessment and monitoring process for the regular review of patients at risk of HAND.

METHODS

Between March and September 2017, 25 experts from four community healthcare services participated in three rounds of a modified Delphi study to reach consensus on the items, monitoring period, and format of assessment tools to identify risk of HAND in PLHIV in the community.

RESULTS

More than 80% consensus was reached at all three Delphi rounds. A flow chart, an initial assessment, and an annual monitoring tool were developed for an ongoing assessment of risk of developing HAND.

CONCLUSION

Twenty percent of PLHIV may develop HAND, a treatable condition. The use of a modified Delphi method led to the successful development of two risk assessment tools to identify those at risk of HAND. The initial assessment tool may be used as a precursor to formal assessment by medical and nursing staff, whereas the annual monitoring tool may assist community-based health professionals in their ongoing assessment of risk of HAND in PLHIV, facilitating early formal medical review for this condition.

Examining Relationships between Metabolism and Persistent Inflammation in HIV Patients on Antiretroviral Therapy

With the advent of antiretroviral therapy (ART), HIV-infected individuals are now living longer and healthier lives. However, ART does not completely restore health and treated individuals are experiencing increased rates of noncommunicable diseases such as dyslipidemia, insulin resistance, type 2 diabetes, cardiovascular disease, and nonalcoholic fatty liver disease. While it is well known that persistent immune activation and inflammation contribute to the development of these comorbid diseases, the mechanisms underlying this chronic activation remain incompletely understood. In this review, we will discuss emerging evidence that suggests that alterations in cellular metabolism may play a central role in driving this immune dysfunction in HIV patients on ART.

Neurological soft signs as a marker of cognitive impairment severity in people living with HIV

HIV-associated neurocognitive disorders (HAND) include asymptomatic neurocognitive impairment (ANI), mild neurocognitive disorder (MND) and HIV-associated dementia. Early recognition of HAND is crucial, and usually requires thorough neuropsychological testing. Neurological soft signs (NSS), i.e. minor motor and sensory changes, a common feature in severe psychiatric disorders, may facilitate early diagnosis. NSS were examined using the Heidelberg NSS Scale in 18 patients with ANI, 21 with MND, 28 HIV positive patients without HAND, and 39 healthy controls matched for age, gender, and education. The highest NSS scores were obtained in the MND patients (13.3 ± 10.0, p < 0.0001) followed by those with ANI (11.7 ± 10.6), the HIV positive subjects without neurocognitive deficits (8.0 ± 4.1) and the healthy controls (3.8 ± 3.2). This result was confirmed when age and years of school education were entered as covariates. No significant correlations between NSS and CD4 counts or any other clinical variables were found among the HIV positive groups. Our results demonstrate that NSS are frequently found in both ANI and MND but not HIV positive patients without neurocognitive deficits. NSS may facilitate the screening of HIV positive patients for ANI and MND as an easier and less expensive clinical tool.

4-(E)-{(p-tolylimino)-methylbenzene-1,2-diol} (TIMBD) suppresses HIV1-gp120 mediated production of IL6 and IL8 but not CCL5

Human immunodeficiency virus (HIV) has been associated with inflammatory effects that may potentially result in neurodegenerative changes and a number of newer chemotherapeutic agents are being tested to ameliorate these effects. In this study, we investigated the anti-neuroinflammatory activity of a novel resveratrol analog 4-(E)-{(p-tolylimino)-methylbenzene-1,2-diol} (TIMBD) against HIV1-gp120 induced neuroinflammation in SVG astrocytes. SVG astrocytic cells were pretreated with TIMBD or resveratrol (RES) and then transfected with a plasmid encoding HIV1-gp120. The mRNA and protein expression levels of proinflammatory cytokines IL6, IL8 and CCL5 were determined. Protein expression levels of NF-κB, AP1, p-STAT3, p-AKT, p-IKKs and p-p38 MAPK were also determined. TIMBD inhibited gp120-induced RNA and protein expression levels of IL6 and IL8, but not that of CCL5 in SVG astrocytes. Moreover, TIMBD attenuated gp120-induced phosphorylation of cJUN, cFOS, STAT3, p38-MAPK, AKT and IKKs, and the nuclear translocation of NF-κB p-65 subunit whereas RES mostly affected NF-κB protein expression levels. Our results suggest that TIMBD exerts anti-inflammatory effects better than that of RES in SVG astrocytes in vitro. These effects seem to be regulated by AP1, STAT-3 and NF-κB signaling pathways. TIMBD may thus have a potential of being a novel agent for treating HIV1-gp120-mediated neuroinflammatory diseases.

Associations between brain microstructures, metabolites, and cognitive deficits during chronic HIV-1 infection of humanized mice

Background

Host-species specificity of the human immunodeficiency virus (HIV) limits pathobiologic, diagnostic and therapeutic research investigations to humans and non-human primates. The emergence of humanized mice as a model for viral infection of the nervous system has overcome such restrictions enabling research for HIV-associated end organ disease including behavioral, cognitive and neuropathologic deficits reflective of neuroAIDS. Chronic HIV-1 infection of NOD/scid-IL-2Rg_c^null mice transplanted with human CD34⁺ hematopoietic stem cells (CD34-NSG) leads to persistent viremia, profound CD4⁺ T lymphocyte loss and infection of human monocyte-macrophages in the meninges and perivascular spaces. Murine cells are not infected with virus.

Methods

Changes in mouse behavior were measured, starting at 8 weeks after viral infection. These were recorded coordinate with magnetic resonance spectroscopy metabolites including N-acetylaspartate (NAA), creatine and choline. Diffusion tensor magnetic resonance imaging (DTI) was recorded against multispectral immunohistochemical staining for neuronal markers that included microtubule associated protein-2 (MAP2), neurofilament (NF) and synaptophysin (SYN); for astrocyte glial fibrillary acidic protein (GFAP); and for microglial ionized calcium binding adaptor molecule 1 (Iba-1). Oligodendrocyte numbers and integrity were measured for myelin associated glycoprotein (MAG) and myelin oligodendrocyte glycoprotein (MOG) antigens.

Results

Behavioral abnormalities were readily observed in HIV-1 infected mice. Longitudinal open field activity tests demonstrated lack of habituation indicating potential for memory loss and persistent anxiety in HIV-1 infected mice compared to uninfected controls. End-point NAA and creatine in the cerebral cortex increased with decreased MAG. NAA and glutamate decreased with decreased SYN and MAG. Robust inflammation reflected GFAP and Iba-1 staining intensities. DTI metrics were coordinate with deregulation of NF, Iba-1, MOG and MAG levels in the whisker barrel and MAP2, NF, MAG, MOG and SYN in the corpus callosum.

Conclusions

The findings are consistent with some of the clinical, biochemical and pathobiologic features of human HIV-1 nervous system infections. This model will prove useful towards investigating the mechanisms of HIV-1 induced neuropathology and in developing novel biomarkers and therapeutic strategies for disease.

Electronic supplementary material

The online version of this article (doi:10.1186/1750-1326-9-58) contains supplementary material, which is available to authorized users.

Taming HIV-related inflammation with physical activity: a matter of timing

Many sets of data indicate that HIV-infected individuals maintain a low level of chronic immune activation and inflammation even in the presence of effective antiretroviral therapy (ART). This residual immune activation seems to be associated with accelerated aging and an increased incidence of non-AIDS-defining illnesses. Several published studies suggest that physical activity is a beneficial nonpharmacological intervention to reduce chronic inflammation. However, currently available data on the potential benefits of regular physical exercises for HIV-infected individuals are limited. Nonetheless, increasing evidence suggests that the introduction of regular physical exercise in the clinical management of HIV-infected individuals may have a significant positive impact in reducing some of the long-term complications of both infection and ART. Based on a comprehensive review of the existing data, we propose that regular physical exercise should be further studied as a potential antiinflammatory, nonpharmacological approach to be used to treat HIV residual disease and non-AIDS-defining illnesses in ART-treated HIV-infected individuals.