Background
Chronic inflammation in people with HIV (PWH) is linked to cardiovascular disease (CVD). We previously described distinct inflammatory clusters from 24 biomarkers that were associated with CVD. We aimed to validate these results in an independent cohort and assess whether additional biomarkers or gut microbiome signatures could enhance CVD prediction in PWH.
Methods
In plasma from people with and without HIV from three international cohorts we measured 55 biomarkers by quantitative immunoassays. Principal component analysis (PCA) and hierarchical clustering (HC) was performed on the original 24 biomarkers and a recursive feature addition (RFA) model used to assess the stepwise addition of 31 additional biomarkers, selecting those that enhanced the model for repeat PCA and HC. Stool microbiome was analysed by 16S rRNA sequencing, with differentially abundant species identified by Analysis of Compositions of Microbiomes with Bias Correction (ANCOM-BC) and correlated to biomarkers using Spearman correlation. Multinomial logistic regression explored associations between clusters and CVD outcomes. Data are median (IQR) unless stated.
Results
We included 408 participants (age 50 (43–58) years; 83% male; 68% White; 78% PWH). Consistent with previous studies, initial PCA of 24 biomarkers again revealed 3 clusters, with cluster 3 (n= 41) showing elevated markers of inflammation (IL1-β, IL-6, TNF-α), immune regulation (TSLP, MIP1-α), and T-cell differentiation (IL2, IL12, IFN-γ). Cluster 3 participants were older (51 (47-55) years), had higher BMI (27.5 (24.4–29.2)kg/m2), higher triglycerides (1.98 (1.23- 2.62) mmol/L), and higher CVD prevalence (n= 6 (39%)). After RFA, 13 of the 31 additional biomarkers enhanced the PCA, with cluster 3 now including GM-CSF, IFN-α2a, TGF-α, and Thrombopoietin, with a stronger CVD association (OR: 2.13 (95% CI: 1.03, 4.4), p= 0.04). In cluster 3, ANCOM-BC revealed 5 enriched and 7 depleted microbial species . Within cluster 3, IFN-l2, MIP-1 α, MCP-1, CD40-ligand and TGF-α all correlated with depletion of short-chain fatty acid-producing species (B. coprocola, B. massiliensis, F. mortiferum, D. invisus, Figure) that are linked to regulation of inflammation and CVD.
Conclusions
This analysis again confirmed distinct inflammatory clusters associated with CVD in an independent cohort of PWH. Clusters enhanced with additional biomarkers better predicted CVD and identified lined gut microbiome signatures linked to CVD.