Central nervous system (CNS) complications are common among people with HIV (PWH), even those who are taking antiretroviral therapy (ART). The spectrum of CNS complications is broad, ranging from mild cognitive deficits that do not affect daily functioning to life-threatening encephalitis. Cognitive and mood disorders are among the most common CNS diseases that affect PWH and share a common risk factor, inflammation. Inflammation persists in effectively treated PWH for multiple reasons, including production of HIV RNA and proteins and gut dysbiosis and microbial translocation. CHARTER is a multisite, U.S.-based, neuroHIV cohort study that is funded by NIH and that has investigated CNS disorders in PWH for nearly two decades, during which it has completed more than 6,000 assessments generating more than 10 million data points. CHARTER has made important contributions to understanding the frequency, risk factors, and pathogenesis of these disorders. In recent years, new questions have arisen about the heterogeneity, biological basis, clinical impact, and management of CNS disorders. This debate has highlighted the need to create new classifications of CNS disorders in PWH that are more biology-based. We propose to use methods such as machine learning and an agnostic approach to categorize CHARTER?s high-dimensional neurobehavioral, neuromedical, psychiatric, substance use, and imaging data. Such analyses would yield not just cognitive phenotypes but biopsychosocial (BPS) phenotypes that could identify new mechanisms that lead to clinically useful diagnostic tests, new therapies, and better management of CNS disorders in PWH. Our overarching goal is to leverage prior investment in CHARTER by using its data and stored specimens to a) better understand cognitive and BPS phenotypes in PWH and b) relate them to biological mechanisms. To accomplish this, we will use unsupervised and supervised machine learning methods to analyze data from CHARTER?s comprehensive assessments with the goal of identifying new cognitive and BPS phenotypes (Aim 1). We will then compare these new phenotypes to high-dimensional data from CHARTER?s completed genomewide association study as well as new data we will generate on inflammation (45-plex bead-based array) and highly novel assays of the microbiome and the metabolome in blood and CSF (Aim 2). Our analyses will include a specific focus how sex affects the observed relationships. To determine if this novel approach relates more strongly to biology than prior methods, we will also compare the performance of the new phenotypes to those defined by the 2007 HAND criteria. This highly innovative application is supported by strong preliminary data, responds well to Office of AIDS Research priorities, and will address key gaps in the field, including the need to better understand the pathogenesis of comorbid disease.
Cognitive and mood disorders occur more commonly in people with HIV than in the general population but the field still does not fully understand why and has no effective therapies for most of those who are affected. This project will take a new approach to understanding how cognition, mood, substance use, and medical characteristics cluster together and will identify new biological mechanisms associated with these conditions. The successful project could lead to new diagnostic tests and therapies for these disorders, which would have substantial public health relevance.
