The contribution of HIV infection to intracranial arterial remodeling: a pilot study

Abstract

Pathological arterial wall changes have been cited as potential mechanisms of cerebrovascular disease in the HIV population. We hypothesize that dilatation would be present in arterial walls of patients with HIV compared to controls. Fifty-one intracranial arteries, obtained from autopsies of five individuals with HIV infection and 13 without, were fixed, embedded, stained, and digitally photographed. Cross-sectional areas of intima, media, adventitia and lumen were measured by preset color thresholding. A measure of arterial remodeling was obtained by calculating the ratio between the lumen diameter and the thickness of the arterial wall. Higher numbers indicate arterial dilatation, while lower numbers indicate arterial narrowing. HIV-infected brain donors were more frequently black (80% vs. 15%, P = 0.02) compared with uninfected donors. Inter and intra-reader agreement measures were excellent. The continuous measure of vascular remodeling was significantly higher in the arteries from HIV donors (β = 2.8, P = 0.02). Adjustments for demographics and clinical covariates strengthen this association (β = 9.3, P = 0.01). We found an association of HIV infection with outward brain arterial remodeling. This association might be mediated by a thinner media layer. The reproduction of these results and the implications of this proposed pathophysiology merits further study.

Fig. 1

Scatter plot of individual arterial wall components and lumen by wall thickness to lumen diameter ratio. 1A: This plot shows that greater degrees of stenosis correlate with lower lumen-to-wall ratio (LWR). 1B and 1C: A thinner media is associated with a lower LWR, probably a reflection of increased intima proportion within the arterial wall. 1D: While the degree of stenosis remains stable, there is a growing internal elastic lamina area (IEL). The more vertical line and the question mark indicate a potential increase in stenosis with no more IEL accommodation.

Fig. 2

Examples of brain arterial remodeling by HIV status. It can be observed that brain arteries from HIV brain donors look thinner and more dilated that the HIV-negative controls.