Pre-clinical atherosclerosis is found at post-mortem, in the brains of men with HIV.

The aim of this study is to ascertain the burden of pre-clinical atherosclerotic changes in the brains of young adult males with HIV and explore the impact of anti-retroviral therapy (ART). The study design is case-control, cross-sectional. Histological sections from HIV-positive post-mortem brain samples, with no associated opportunistic infection, from the MRC Edinburgh brain bank were evaluated. These were age and sex matched with HIV-negative controls. Immunohistochemical stains were performed to evaluate characteristics of atherosclerosis. The pathological changes were graded blinded to the HIV status and a second histopathologist reassessed 15%. Univariable models were used for statistical analyses; p ≤ 0.05 was considered significant. Nineteen HIV-positive post-mortem cases fulfilled our inclusion criteria. Nineteen HIV-negative controls were selected. We assessed mostly small-medium-sized vessels. For inflammation (CD45), 7 (36%) of the HIV+ had moderate/severe changes compared with none for the HIV- group (p < 0.001). Moderate/severe increase in smooth muscle remodeling (SMA) was found in 8 (42%) HIV+ and 0 HIV- brains (p < 0.001). Moderate/severe lipoprotein deposition (LOX-1) was found in 3 (15%) and 0 HIV-brains (p < 0.001). ART was associated with less inflammation [5 (63%) no ART versus 2 (18%) on ART (p = 0.028)] but was not associated with reduced lipid deposition or smooth muscle damage. In HIV infection, there are pre-clinical small- to medium-sized vessel atherosclerotic changes and ART may have limited impact on these changes. This could have implications on the increasing burden of cerebrovascular disease in HIV populations and warrants further investigation.

Hematopoietic stem and progenitor cells directly participate in host immune response.

The properties of hematopoietic stem and progenitor cells (HSPCs), including self-renewal and pluripotency, have been extensively studied. These features have been explored in the management of several haematological disorders and malignancies. Although their role as precursors of innate immune cells is well understood, little is known about their direct participation in host immune response. In this review, we explicate the direct role of HSPCs in the host immune response and highlight therapeutic options for the infectious disease burden that is currently ravaging the world, including COVID-19.