Immune Biomarkers in the Prediction of Future Myocardial Infarctions in People With Human Immunodeficiency Virus

Gut microbiome and cardiometabolic comorbidities in people living with HIV

BACKGROUND

Despite modern antiretroviral therapy (ART), people living with HIV (PLWH) have increased relative risk of inflammatory-driven comorbidities, including cardiovascular disease (CVD). The gut microbiome could be one of several driving factors, along with traditional risk factors and HIV-related risk factors such as coinfections, ART toxicity, and past immunodeficiency.

RESULTS

PLWH have an altered gut microbiome, even after adjustment for known confounding factors including sexual preference. The HIV-related microbiome has been associated with cardiometabolic comorbidities, and shares features with CVD-related microbiota profiles, in particular reduced capacity for short-chain fatty acid (SCFA) generation. Substantial inter-individual variation has so far been an obstacle for applying microbiota profiles for risk stratification. This review covers updated knowledge and recent advances in our understanding of the gut microbiome and comorbidities in PLWH, with specific focus on cardiometabolic comorbidities and inflammation. It covers a comprehensive overview of HIV-related and comorbidity-related dysbiosis, microbial translocation, and microbiota-derived metabolites. It also contains recent data from studies in PLWH on circulating metabolites related to comorbidities and underlying gut microbiota alterations, including circulating levels of the SCFA propionate, the histidine-analogue imidazole propionate, and the protective metabolite indole-3-propionic acid.

CONCLUSIONS

Despite recent advances, the gut microbiome and related metabolites are not yet established as biomarkers or therapeutic targets. The review gives directions for future research needed to advance the field into clinical practice, including promises and pitfalls for precision medicine. Video Abstract.

A Mass Spectrometry-Based Proteome Study of Twin Pairs Discordant for Incident Acute Myocardial Infarction within Three Years after Blood Sampling Suggests Novel Biomarkers

Acute myocardial infarction (AMI) is a major cause of mortality and morbidity worldwide, yet biomarkers for AMI in the short- or medium-term are lacking. We apply the discordant twin pair design, reducing genetic and environmental confounding, by linking nationwide registry data on AMI diagnoses to a survey of 12,349 twins, thereby identifying 39 twin pairs (48-79 years) discordant for their first-ever AMI within three years after blood sampling. Mass spectrometry of blood plasma identified 715 proteins. Among 363 proteins with a call rate > 50%, imputation and stratified Cox regression analysis revealed seven significant proteins (FDR < 0.05): FGD6, MCAM, and PIK3CB reflected an increased level in AMI twins relative to their non-AMI co-twins (HR > 1), while LBP, IGHV3-15, C1RL, and APOC4 reflected a decreased level in AMI twins relative to their non-AMI co-twins (HR < 1). Additional 50 proteins were nominally significant (p < 0.05), and bioinformatics analyses of all 57 proteins revealed biology within hemostasis, coagulation cascades, the immune system, and the extracellular matrix. A protein-protein-interaction network revealed Fibronectin 1 as a central hub. Finally, technical validation confirmed MCAM, LBP, C1RL, and APOC3. We put forward novel biomarkers for incident AMI, a part of the proteome field where markers are surprisingly rare and where additional studies are highly needed.

Injecting drug use and hepatitis C virus infection independently increase biomarkers of inflammatory disease risk which are incompletely restored by curative direct-acting antiviral therapy

Background

Hepatitis C virus (HCV) infections are more prevalent in people who inject drugs (PWID) who often experience additional health risks. HCV induces inflammation and immune alterations that contribute to hepatic and non-hepatic morbidities. It remains unclear whether curative direct acting antiviral (DAA) therapy completely reverses immune alterations in PWID.

Methods

Plasma biomarkers of immune activation associated with chronic disease risk were measured in HCV-seronegative (n=24) and HCV RNA+ (n=32) PWID at baseline and longitudinally after DAA therapy. Adjusted generalised estimating equations were used to assess longitudinal changes in biomarker levels. Comparisons between community controls (n=29) and HCV-seronegative PWID were made using adjusted multiple regression modelling.

Results

HCV-seronegative PWID exhibited significantly increased levels of inflammatory biomarkers including soluble (s) TNF-RII, IL-6, sCD14 and sCD163 and the diabetes index HbA1c as compared to community controls. CXCL10, sTNF-RII, vascular cell adhesion molecule-1 and lipopolysaccharide binding protein (LBP) were additionally elevated in PWID with viremic HCV infection as compared to HCV- PWID. Whilst curative DAA therapy reversed some biomarkers, others including LBP and sTNF-RII remained elevated 48 weeks after HCV cure.

Conclusion

Elevated levels of inflammatory and chronic disease biomarkers in PWID suggest an increased risk of chronic morbidities such as diabetes and cardiovascular disease. HCV infection in PWID poses an additional disease burden, amplified by the incomplete reversal of immune dysfunction following DAA therapy. These findings highlight the need for heightened clinical surveillance of PWID for chronic inflammatory diseases, particularly those with a history of HCV infection.

Pro-inflammatory and pro-resolving lipid mediators of inflammation in HIV: effect of aspirin intervention

BACKGROUND

Persons with HIV (PWH) have an increased risk of cardiovascular disease (CVD) compared to HIV-seronegative individuals (SN). Inflammation contributes to this risk but the role of lipid mediators, with central roles in inflammation, in HIV infection remain to be established; further aspirin reduces CVD risk in the general population through production of some of these anti-inflammatory lipid mediators, but they have not been studied in PWH.

METHODS

We evaluated the relationship between plasma lipid mediators (i.e. 50 lipid mediators including classic eicosanoids and specialized pro-resolving mediators (SPMs)) and HIV status; and the impact of aspirin in PWH on regulating these autacoids. Plasma samples were obtained from 110 PWH receiving antiretroviral therapy (ART) from a randomized trial of aspirin (ACTG-A5331) and 107 matched SN samples (MACS-WIHS Combined Cohort).

FINDINGS

PWH had lower levels of arachidonic acid-derived pro-inflammatory prostaglandins (PGs: PGE2 and PGD2) and thromboxanes (Tx: TxB2), and higher levels of select pro-resolving lipid mediators (e.g. RvD4 and MaR2n-3 DPA) compared to SN. At the interval tested, aspirin intervention was observed to reduced PGs and Tx, and while we did not observe an increase in aspirin triggered mediators, we observed the upregulation of other SPM in aspirin treated PWH, namely MaR2n-3 DPA.

INTERPRETATION

Together these observations demonstrate that plasma lipid mediators profiles, some with links to systemic inflammation and CVD risk, become altered in PWH. Furthermore, aspirin intervention did not increase levels of aspirin-triggered pro-resolving lipid mediators, consistent with other reports of an impaired aspirin response in PWH.

FUNDING

NIH.

The Gut Microbiome, Microbial Metabolites, and Cardiovascular Disease in People Living with HIV

PURPOSE OF REVIEW

To synthesize recent evidence relating the gut microbiome and microbial metabolites to cardiovascular disease (CVD) in people living with HIV (PLWH).

RECENT FINDINGS

A few cross-sectional studies have reported on the gut microbiome and cardiovascular outcomes in the context of HIV, with no consistent patterns emerging. The largest such study found that gut Fusobacterium was associated with carotid artery plaque. More studies have evaluated microbial metabolite trimethylamine N-oxide with CVD risk in PLWH, but results were inconsistent, with recent prospective analyses showing null effects. Studies of other microbial metabolites are scarce. Microbial translocation biomarkers (e.g., lipopolysaccharide binding protein) have been related to incident CVD in PLWH. Microbial translocation may increase CVD risk in PLWH, but there is insufficient and/or inconsistent evidence regarding specific microbial species and microbial metabolites associated with cardiovascular outcomes in PLWH. Further research is needed in large prospective studies integrating the gut microbiome, microbial translocation, and microbial metabolites with cardiovascular outcomes in PLWH.

CD4:CD8 Ratio and CD8 Cell Count and Their Prognostic Relevance for Coronary Heart Disease Events and Stroke in Antiretroviral Treated Individuals: The Swiss HIV Cohort Study

INTRODUCTION

HIV infection leads to a persistent expansion of terminally CD8 T cells and CD8 T suppressor cells, a marker of chronic immune activation leading to a low CD4:CD8 ratio that may persist in the presence of potent antiretroviral therapy and regained CD4 helper cells. It remains unclear whether a low CD4:CD8 ratio is associated with cardiovascular diseases.

METHODS

We conducted an observational cohort study to investigate the association of immune depression and activation as characterized by the proxy of the CD4:CD8 ratio on the hazard of coronary heart disease (CHD) and stroke among treated individuals living with HIV, while accounting for viral load and known risk factors for cardiovascular diseases and exposure to abacavir or protease inhibitors. We used Cox proportional hazard models with time-dependent cumulative and lagged exposures to account for time-evolving risk factors and avoid reverse causality.

RESULTS

CD4, CD8, and CD4:CD8 immunological markers were not associated with an increased hazard for CHD. CD8 cell count lagged at 12 months above 1000 cells per μL increased the hazard of stroke, after adjusting for sociodemographics, cardiovascular risk factors, and exposure to specific types of antiretroviral drugs.

CONCLUSIONS

This analysis of treated HIV-positive individuals within a large cohort with long-term follow-up does not provide evidence for a prognostic role of immune dysregulation regarding CHD. However, increased CD8 cell count may be a moderate risk factor for stroke. Early detection and treatment of HIV-positive individuals are crucial for an optimal immune restoration and a limited CD8 cells expansion.

Effect of Rosuvastatin Therapy on Biomarkers of Inflammation and Immune Activation in People With Human Immunodeficiency Virus at Intermediate Cardiovascular Risk

BACKGROUND

Statins may help prevent cardiovascular disease (CVD) in people with human immunodeficiency virus (PWH) with chronic inflammation owing to their pleotropic lipid-lowering and anti-inflammatory properties.

METHODS

The impact of 48 weeks of rosuvastatin therapy on inflammation and immune activation in a double-blind, placebo-controlled trial in PWH at moderate cardiovascular disease risk was assessed.

RESULTS

Rosuvastatin did not alter plasma levels of interleukin 6, soluble tumor necrosis factor receptor type 2, CXCL10, soluble CD14, or soluble vascular cellular adhesion molecule 1 (P ≥ .1 for all). Proportions of CD16+ monocyte subsets were increased in PWH receiving rosuvastatin.

CONCLUSIONS

The potential benefits of statin use in PWH with normal lipid levels requires further clinical outcome research.