Immune dysregulation and vascular risk in HIV-infected patients: implications for clinical care

Cardiovascular Risk Estimation Is Suboptimal in People With HIV

BACKGROUND

Established cardiovascular disease (CVD) risk prediction functions may not accurately predict CVD risk in people with HIV. We assessed the performance of 3 CVD risk prediction functions in 2 HIV cohorts.

METHODS AND RESULTS

CVD risk scores were calculated in the Mass General Brigham and Kaiser Permanente Northern California HIV cohorts, using the American College of Cardiology/American Heart Association atherosclerotic CVD function, the FHS (Framingham Heart Study) hard coronary heart disease function and the Framingham Heart Study hard CVD function. Outcomes were myocardial infarction or coronary death for FHS hard coronary heart disease function; and myocardial infarction, stroke, or coronary death for American College of Cardiology/American Heart Association and FHS hard CVD function. We calculated regression coefficients and assessed discrimination and calibration by sex; predicted to observed risk of outcome was also compared. In the combined cohort of 9412, 158 (1.7%) had a coronary heart disease event, and 309 (3.3%) had a CVD event. Among women, CVD risk was generally underestimated by all 3 risk functions. Among men, CVD risk was underestimated by the American College of Cardiology/American Heart Association and FHS hard CVD function, but overestimated by the FHS hard coronary heart disease function. Calibration was poor for women using the FHS hard CVD function and for men using all functions. Discrimination in all functions was good for women (c-statistics ranging from 0.78 to 0.90) and moderate for men (c-statistics ranging from 0.71 to 0.72).

CONCLUSIONS

Established CVD risk prediction functions generally underestimate risk in people with HIV. Differences in model performance by sex underscore the need for both HIV-specific and sex-specific functions. Development of CVD risk prediction models tailored to HIV will enhance care for aging people with HIV.

The Determinants of Elevated Pathobiological Determination of Atherosclerosis in Youth Risk Score in Perinatally HIV-Infected Adolescents in South Africa

BACKGROUND

Youth living with perinatally acquired HIV infection (YLPHIV) are at risk of developing atherosclerotic cardiovascular disease.

METHODS

We determined the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) coronary arteries (CA) and abdominal aorta (AA) risk scores among YLPHIV who are ≥15 years old in Cape Town Adolescent and Antiretroviral Cohort. PDAY score was calculated using non-high-density lipoprotein, high-density lipoprotein cholesterol, hyperglycemia, hypertension, obesity, and smoking; a score ≥1 was considered elevated. HIV viremia was categorized as sustained (SV) = viral load (VL) >50 copies/mL, transient (TV) = mix of VL >50 and ≤50 copies/mL, or sustained-virologic suppression = VL <50 copies/mL throughout the study. Among YLPHIV, logistic models were fit to assess factors associated with elevated PDAY.

RESULTS

Overall, 218 YLPHIV [median age 16.8 (interquartile range: 15.9-17.8) years, male 47%] were included. Among YLPHIV, 8% (n = 17) had SV, and 54% (n = 118) had TV. Median antiretroviral therapy (ART) duration was 12 (interquartile range: 8-14) years. Among YLPHIV, 30.3% and 18.4% had elevated PDAY for CA and AA, respectively.Among YLPHIV, SV [adjusted odds ratio (aOR) = 18.4, P < 0.01] and TV (aOR = 2.10, P = 0.04) compared with virologic suppression and ART duration in years (aOR = 1.12, P = 0.03) were associated with elevated CA. Male sex was associated with both elevated CA and AA (aOR = 2.14, P = 0.02, and aOR = 3.43, P = 0.01, respectively) and association of SV with elevated AA (aOR = 3.24, P = 0.09).

CONCLUSIONS

A substantial proportion of YLPHIV have PDAY scores reflecting increased aggregate atherosclerotic risk. Among YLPHIV, viremia, lifetime ART duration, and male sex contribute to this risk, highlighting the importance of HIV control and the need to monitor cardiometabolic health.

Cardiovascular Risk Prediction Functions Underestimate Risk in HIV Infection

BACKGROUND

Cardiovascular disease (CVD) risk is elevated in HIV-infected individuals, with contributions from both traditional and nontraditional risk factors. The accuracy of established CVD risk prediction functions in HIV is uncertain. We sought to assess the performance of 3 established CVD risk prediction functions in a longitudinal cohort of HIV-infected men.

METHODS

The FHS (Framingham Heart Study) functions for hard coronary heart disease (FHS CHD) and atherosclerotic CVD (FHS ASCVD) and the American College of Cardiology/American Heart Association ASCVD function were applied to the Partners HIV cohort. Risk scores were calculated between January 1, 2006, and December 31, 2008. Outcomes included CHD (myocardial infarction or coronary death) for the FHS CHD function and ASCVD (myocardial infarction, stroke, or coronary death) for the FHS ASCVD and American College of Cardiology/American Heart Association ASCVD functions. We investigated the accuracy of CVD risk prediction for each function when applied to the HIV cohort using comparison of Cox regression coefficients, discrimination, and calibration.

RESULTS

The HIV cohort was comprised of 1272 men followed for a median of 4.4 years. There were 78 (6.1%) ASCVD events; the 5-year incidence rate was 16.4 per 1000 person-years. Discrimination was moderate to poor as indicated by the low c statistic (0.68 for FHS CHD, 0.65 for American College of Cardiology/American Heart Association ASCVD, and 0.67 for FHS ASCVD). Observed CVD risk exceeded the predicted risk for each of the functions in most deciles of predicted risk. Calibration, or goodness of fit of the models, was consistently poor, with significant χ²P values for all functions. Recalibration did not significantly improve model fit.

CONCLUSIONS

Cardiovascular risk prediction functions developed for use in the general population are inaccurate in HIV infection and systematically underestimate risk in a cohort of HIV-infected men. Development of tailored CVD risk prediction functions incorporating traditional CVD risk factors and HIV-specific factors is likely to result in more accurate risk estimation to guide preventative CVD care.

HIV-associated changes in the enteric microbial community: potential role in loss of homeostasis and development of systemic inflammation

Supplemental Digital Content is available in the text

Purpose of review

Despite HIV therapy advances, average life expectancy in HIV-infected individuals on effective treatment is significantly decreased relative to uninfected persons, largely because of increased incidence of inflammation-related diseases, such as cardiovascular disease and renal dysfunction. The enteric microbial community could potentially cause this inflammation, as HIV-driven destruction of gastrointestinal CD4⁺ T cells may disturb the microbiota–mucosal immune system balance, disrupting the stable gut microbiome and leading to further deleterious host outcomes.

Recent findings

Varied enteric microbiome changes have been reported during HIV infection, but unifying patterns have emerged. Community diversity is decreased, similar to pathologies such as inflammatory bowel disease, obesity, and Clostridium difficile infection. Many taxa frequently enriched in HIV-infected individuals, such as Enterobacteriaceae and Erysipelotrichaceae, have pathogenic potential, whereas depleted taxa, such as Bacteroidaceae and Ruminococcaceae, are more linked with anti-inflammatory properties and maintenance of gut homeostasis. The gut viral community in HIV has been found to contain a greater abundance of pathogenesis-associated Adenoviridae and Anelloviridae. These bacterial and viral changes correlate with increased systemic inflammatory markers, such as serum sCD14, sCD163, and IL-6.

Summary

Enteric microbial community changes may contribute to chronic HIV pathogenesis, but more investigation is necessary, especially in the developing world population with the greatest HIV burden (Video, Supplemental Digital Content 1, which includes the authors’ summary of the importance of the work).

Hepatic, Renal, Hematologic, and Inflammatory Markers in HIV-Infected Children on Long-term Suppressive Antiretroviral Therapy

BACKGROUND

Data on long-term toxicity of antiretroviral therapy (ART) in HIV-infected children are sparse. PENPACT-1 was an open-label trial in which HIV-infected children were assigned randomly to receive protease inhibitor (PI)- or nonnucleoside reverse-transcriptase inhibitor (NNRTI)-based ART.

METHODS

We examined changes in clinical, immunologic, and inflammatory markers from baseline to year 4 in the subset of children in the PENPACT-1 study who experienced viral suppression between week 24 and year 4 of ART. Liver enzyme, creatinine, and cholesterol levels and hematologic parameters were assessed during the trial. Cystatin C, high-sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), d-dimer, and soluble CD14 (sCD14) were assayed from cryopreserved specimens.

RESULTS

Ninety-nine children (52 on PI-based and 47 on NNRTI-based ART) met inclusion criteria. The median age at initiation of ART was 6.5 years (interquartile range [IQR], 3.7-13.4 years), and 22% were aged <3 years at ART initiation; 56% of the PI-treated children received lopinavir/ritonavir, and 70% of NNRTI-treated children received efavirenz initially. We found no evidence of significant clinical toxicity in either group; growth, liver, kidney, and hematologic parameters either remained unchanged or improved between baseline and year 4. Total cholesterol levels increased modestly, but no difference between the groups was found. IL-6 and hs-CRP levels decreased more after 4 years in the NNRTI-based ART group. The median change in IL-6 level was -0.35 pg/ml in the PI-based ART group and -1.0 in the NNRTI-based ART group (P = .05), and the median change in hs-CRP level was 0.25 µg/ml in the PI-based ART group and -0.95 µg/ml in the NNRTI-based ART group (P = .005).

CONCLUSION

These results support the safety of prolonged ART use in HIV-infected children and suggest that suppressive NNRTI-based regimens can be associated with lower levels of systemic inflammation.

Persistent Immune Activation and Carotid Atherosclerosis in HIV-Infected Ugandans Receiving Antiretroviral Therapy

BACKGROUND

Human immunodeficiency virus (HIV) infection and associated immune activation predict the risk of cardiovascular disease in resource-rich areas. Less is known about these relationships in sub-Saharan Africa.

METHODS

Beginning in 2005, we enrolled subjects in southwestern Uganda into a cohort at the time of antiretroviral therapy (ART) initiation. Multiple immune activation measures were assessed before and 6 months after ART initiation. Beginning in 2013, participants aged >40 years underwent metabolic profiling, including measurement of hemoglobin A1c and lipid levels and carotid ultrasonography. We fit regression models to identify traditional and HIV-specific correlates of common carotid intima media thickness (CCIMT).

RESULTS

A total of 105 participants completed carotid ultrasonography, with a median completion time of 7 years following ART initiation. Age, low-density lipoprotein cholesterol level, and pre-ART HIV load were correlated with CCIMT. No association was found between CCIMT and any pre-ART biomarkers of immune activation. However, in multivariable models adjusted for cardiovascular disease risk factors, lower absolute levels of soluble CD14 and interleukin 6 and greater declines in the CD14 level and kynurenine-tryptophan ratio after 6 months of ART predicted a lower CCIMT years later (P < .01).

CONCLUSIONS

Persistent immune activation despite ART-mediated viral suppression predicts the future atherosclerotic burden among HIV-infected Ugandans. Future work should focus on clinical correlates of these relationships, to elucidate the long-term health priorities for HIV-infected people in the region.

HIV-associated large-vessel vasculopathy: a review of the current and emerging clinicopathological spectrum in vascular surgical practice

An established relationship exists between human immunodeficiency virus (HIV) and the vascular system, which is characterised by clinical expressions of aneurysmal and occlusive disease that emanate from a common pathological process. The exact pathogenesis is currently unknown; attempts to implicate opportunistic pathogens have been futile. Theories converge on leucocytoclastic vasculitis with the vaso vasora as the vasculopathic epicentre. It is thought that the virus itself or viral proteins trigger the release of inflammatory mediators that cause endothelial dysfunction and smooth muscle proliferation leading to vascular injury and thrombosis. The beneficial effects of highly active anti-retroviral therapy alter the natural history of the disease profile and promote longevity but are negated by cardiovascular complications. Atherosclerosis is an emerging challenge. Presently patients are managed by standard surgical protocols because of non-existent universal surgical interventional guidelines. Clinical response to treatment is variable and often compounded by complications of graft occlusion, sepsis and poor wound healing. The clinical, imaging and pathological observations position HIV-associated large-vessel vasculopathy as a unique entity. This review highlights the spectrum of HIV-associated large-vessel aneurysmal, occlusive and atherosclerotic disease in vascular surgical practice.

Aggregate risk of cardiovascular disease among adolescents perinatally infected with the human immunodeficiency virus

BACKGROUND

Perinatally HIV-infected adolescents may be susceptible to aggregate atherosclerotic cardiovascular disease risk, as measured by the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) coronary arteries and abdominal aorta risk scores, as a result of prolonged exposure to HIV and antiretroviral therapy.

METHODS AND RESULTS

Coronary arteries and abdominal aorta PDAY scores were calculated for 165 perinatally HIV-infected adolescents, using a weighted combination of modifiable risk factors: dyslipidemia, cigarette smoking, hypertension, obesity, and hyperglycemia. Demographic and HIV-specific predictors of scores ≥1 were identified, and trends in scores over time were assessed. Forty-eight percent and 24% of the perinatally HIV-infected adolescents had coronary arteries and abdominal aorta scores ≥1, representing increased cardiovascular disease risk factor burden. Significant predictors of coronary arteries scores ≥1 included male sex, history of an AIDS-defining condition, longer duration of use of a ritonavir-boosted protease inhibitor, and no prior use of tenofovir. Significant predictors of abdominal aorta scores ≥1 included suppressed viral load, history of an AIDS-defining condition, and longer duration of boosted protease inhibitor use. No significant changes in coronary arteries and abdominal aorta risk scores were observed over the 4-year study period.

CONCLUSIONS

A substantial proportion of perinatally HIV-infected youth have high PDAY scores, reflecting increased aggregate atherosclerotic cardiovascular disease risk factor burden. High scores were predicted by HIV disease severity and boosted protease inhibitor use. PDAY scores may be useful in identifying high-risk youth who may benefit from early lifestyle or clinical interventions.

Immune activation in HIV-infected aging women on antiretrovirals--implications for age-associated comorbidities: a cross-sectional pilot study

Background

Persistent immune activation and microbial translocation associated with HIV infection likely place HIV-infected aging women at high risk of developing chronic age-related diseases. We investigated immune activation and microbial translocation in HIV-infected aging women in the post-menopausal ages.

Methods

Twenty-seven post-menopausal women with HIV infection receiving antiretroviral treatment with documented viral suppression and 15 HIV-negative age-matched controls were enrolled. Levels of immune activation markers (T cell immune phenotype, sCD25, sCD14, sCD163), microbial translocation (LPS) and biomarkers of cardiovascular disease and impaired cognitive function (sVCAM-1, sICAM-1 and CXCL10) were evaluated.

Results

T cell activation and exhaustion, monocyte/macrophage activation, and microbial translocation were significantly higher in HIV-infected women when compared to uninfected controls. Microbial translocation correlated with T cell and monocyte/macrophage activation. Biomarkers of cardiovascular disease and impaired cognition were elevated in women with HIV infection and correlated with immune activation.

Conclusions

HIV-infected antiretroviral-treated aging women who achieved viral suppression are in a generalized status of immune activation and therefore are at an increased risk of age-associated end-organ diseases compared to uninfected age-matched controls.

HIV infection and stroke: current perspectives and future directions

HIV infection can result in stroke via several mechanisms, including opportunistic infection, vasculopathy, cardioembolism, and coagulopathy. However, the occurrence of stroke and HIV infection might often be coincidental. HIV-associated vasculopathy describes various cerebrovascular changes, including stenosis and aneurysm formation, vasculitis, and accelerated atherosclerosis, and might be caused directly or indirectly by HIV infection, although the mechanisms are controversial. HIV and associated infections contribute to chronic inflammation. Combination antiretroviral therapies (cART) are clearly beneficial, but can be atherogenic and could increase stroke risk. cART can prolong life, increasing the size of the ageing population at risk of stroke. Stroke management and prevention should include identification and treatment of the specific cause of stroke and stroke risk factors, and judicious adjustment of the cART regimen. Epidemiological, clinical, biological, and autopsy studies of risk, the pathogenesis of HIV-associated vasculopathy (particularly of arterial endothelial damage), the long-term effects of cART, and ideal stroke treatment in patients with HIV are needed, as are antiretrovirals that are without vascular risk.

Potential cardiovascular disease risk markers among HIV-infected women initiating antiretroviral treatment

BACKGROUND

Inflammation and hemostasis perturbation may be involved in vascular complications of HIV infection. We examined atherogenic biomarkers and subclinical atherosclerosis in HIV-infected adults before and after beginning highly active antiretroviral therapy (HAART).

METHODS

In the Women's Interagency HIV Study, 127 HIV-infected women studied pre and post HAART were matched to HIV-uninfected controls. Six semiannual measurements of soluble CD14, tumor necrosis factor (TNF) alfa, soluble interleukin (IL) 2 receptor, IL-6, IL-10, monocyte chemoattractant protein 1, D-dimer, and fibrinogen were obtained. Carotid artery intima-media thickness was measured by B-mode ultrasound.

RESULTS

Relative to HIV-uninfected controls, HAART-naive HIV-infected women had elevated levels of soluble CD14 (1945 vs 1662 ng/mL, Wilcoxon signed rank P < 0.0001), TNF-α (6.3 vs 3.4 pg/mL, P < 0.0001), soluble IL-2 receptor (1587 vs 949 pg/mL, P < 0.0001), IL-10 (3.3 vs 1.9 pg/mL, P < 0.0001), monocyte chemoattractant protein 1 (190 vs 163 pg/mL, P < 0.0001), and D-dimer (0.43 vs 0.31 μg/mL, P < 0.01). Elevated biomarker levels declined after HAART. Although most biomarkers normalized to HIV-uninfected levels, in women on effective HAART, TNF-α levels remained elevated compared with HIV-uninfected women (+0.8 pg/mL, P = 0.0002). Higher post-HAART levels of soluble IL-2 receptor (P = 0.02), IL-6 (P = 0.05), and D-dimer (P = 0.03) were associated with increased carotid artery intima-media thickness.

CONCLUSIONS

Untreated HIV infection is associated with abnormal hemostasis (eg, D-dimer), proatherogenic (eg, TNF-α), and antiatherogenic (eg, IL-10) inflammatory markers. HAART reduces most inflammatory mediators to HIV-uninfected levels. Increased inflammation and hemostasis are associated with subclinical atherosclerosis in recently treated women. These findings have potential implications for long-term risk of cardiovascular disease in HIV-infected patients, even with effective therapy.