Intestinal microbiota, microbial translocation, and systemic inflammation in chronic HIV infection.

BACKGROUND: Despite effective antiretroviral therapy (ART), patients with chronic human immunodeficiency virus (HIV) infection have increased microbial translocation and systemic inflammation. Alterations in the intestinal microbiota may play a role in microbial translocation and inflammation. METHODS: We profiled the fecal microbiota by pyrosequencing the gene encoding 16S ribosomal RNA (rRNA) and measured markers of microbial translocation and systemic inflammation in 21 patients who had chronic HIV infection and were receiving suppressive ART (cases) and 16 HIV-uninfected controls. RESULTS: The fecal microbial community composition was significantly different between cases and controls. The relative abundance of Proteobacteria, Gammaproteobacteria, Enterobacteriales, Enterobacteriaceae, Erysipelotrichi, Erysipelotrichales, Erysipelotrichaceae, and Barnesiella was significantly enriched in cases, whereas that of Rikenellaceae and Alistipes was depleted. The plasma soluble CD14 level (sCD14) was significantly higher and the endotoxin core immunoglobulin M (IgM) level lower in cases, compared with controls. There were significant positive correlations between the relative abundances of Enterobacteriales and Enterobacteriaceae and the sCD14 level; the relative abundances of Gammaproteobacteria, Enterobacteriales, and Enterobacteriaceae and the interleukin 1ß (IL-1ß) level; the relative abundances of Enterobacteriales and Enterobacteriaceae and the interferon γ level; and the relative abundances of Erysipelotrichi and Barnesiella and the TNF-α level. There were negative correlations between endotoxin core IgM and IL-1ß levels. CONCLUSIONS: Patients who have chronic HIV infection and are receiving suppressive ART display intestinal dysbiosis associated with increased microbial translocation and significant associations between specific taxa and markers of microbial translocation and systemic inflammation. This was an exploratory study, the findings of which need to be confirmed.

Associations of cocaine use and HIV infection with the intestinal microbiota, microbial translocation, and inflammation.

OBJECTIVE: HIV and illicit drug use have been associated with altered nutrition, immune function, and metabolism. We hypothesized that altered composition and decreased diversity of the intestinal microbiota, along with microbial translocation, contribute to nutritional compromise in HIV-infected drug users. METHOD: We enrolled 26 men and 6 women, 15 HIV infected and 17 HIV uninfected, in this exploratory, cross-sectional study; 7 HIV-infected and 7 HIV-uninfected participants had used cocaine within the previous month. We examined the independent effects of cocaine use and HIV infection on the composition and diversity of the intestinal microbiota, determined by 16S rRNA gene pyrosequencing. Using dietary records, anthropometrics, and dual x-ray absorptiometry, we examined the additional effects of nutritional indices on the intestinal microbiota. We compared markers of inflammation and microbial translocation between groups. RESULTS: Cocaine users had a higher relative abundance of Bacteroidetes (M ± SD = 57.0% ± 21 vs. 37.1% ± 23, p = .02) than nonusers. HIV-infected individuals had a higher relative abundance of Proteobacteria (Mdn [interquartile range] = 1.56% [0.5, 2.2] vs. 0.36% [0.2, 0.7], p = .03), higher levels of soluble CD14 and tumor necrosis factor-α, and lower levels of anti-endotoxin core antibodies than uninfected subjects. HIV-infected cocaine users had higher interferon-γ levels than all other groups. Food insecurity was higher in HIV-infected cocaine users. CONCLUSIONS: We identified differences in the relative abundance of major phyla of the intestinal microbiota, as well as markers of inflammation and microbial translocation, based on cocaine use and HIV infection. Nutritional factors, including alcohol use and lean body mass, may contribute to these differences.

High-fat meals do not impair postprandial endothelial function in HIV-infected and uninfected men.

Prior studies have demonstrated impaired endothelium-dependent flow-mediated dilation (FMD) in healthy subjects following a high-fat meal. Compared to uninfected individuals, HIV-infected persons have been shown to have impaired FMD. We examined the effect of two different high-fat meals on endothelial function in HIV-infected and uninfected men. We performed a randomized, parallel group crossover study comparing 47 white men [18 HIV-uninfected, 9 HIV-infected and antiretroviral therapy (ART)-naïve, and 20 HIV-infected men on ART]. Fasting participants consumed one of two randomly assigned high-fat meals of either saturated or polyunsaturated fat, followed at least 24 h later by the other meal. Brachial artery ultrasound measurements to assess vascular reactivity were performed before and 3 h after each dietary challenge. There was no significant difference in mean baseline or postprandial FMD between HIV-infected and HIV-uninfected participants (mean baseline FMD±SD, 9.0%±5 vs. 9.2%±5, p=0.9; mean postprandial FMD±SD, 9.0%±4.7 vs. 9.1%±4.7, p=0.96, respectively). No significant difference in baseline or postprandial change in FMD was found between meals or HIV treatment groups. Fasting lipids and glucose, CD4(+) count, and viral load did not predict FMD in HIV-infected participants. In contrast to previous reports, this study did not demonstrate impaired endothelium-dependent vasodilation after high-fat meals in either HIV-infected or HIV-uninfected men. Moreover, HIV infection itself may not be the primary explanation for the abnormal endothelial function reported in HIV-infected individuals.

Progression of carotid intima-media thickness and coronary artery calcium over 6 years in an HIV-infected cohort.

OBJECTIVE: To evaluate changes in cardiovascular disease risk surrogate markers in a longitudinal cohort of HIV-infected adults over 6 years. DESIGN: Internal carotid artery (ICA) and common carotid artery (CCA) intima-media thickness (IMT), coronary artery calcium (CAC), vascular, and HIV risk factors were prospectively examined over 6 years in HIV-infected adults from 2002 to 2010. SETTING: Longitudinal cohort study with participants from urban center and surrounding communities. SUBJECTS/PARTICIPANTS: Three hundred forty-five HIV-infected participants were recruited from a longitudinal cohort study. Two hundred eleven participants completed the study and were included in this analysis. MAIN OUTCOME MEASURES: Total and yearly ICA and CCA IMT change; CAC score progression. RESULTS: Participants were 27% female and 49% nonwhite; mean age at start was 45 ± 7 years. The median change in ICA and CCA over 6 years was 0.15 mm (0.08, 0.28) and 0.12 mm (0.09, 0.15), respectively. Age, baseline triglycerides ≥150 mg/dL, and pack-years smoking were associated with ICA IMT change; age, cholesterol, nadir CD4 count, and protease inhibitor use were associated with CCA IMT change. Diabetes, HIV viral load, and highly active antiretroviral therapy duration were associated with CAC progression. CONCLUSIONS: Carotid IMT and CAC progressed in this HIV-infected cohort. Some HIV-specific characteristics were associated with surrogate marker changes, but the majority of risk factors continue to be traditional. Aggressive identification and management of modifiable risk factors may reduce progression of cardiovascular disease risk in this population.