Endothelial progenitor cells (EPCs) repair damaged vascular endothelium, and low circulating EPC levels have been associated with cardiovascular disease (CVD). CD34⁺/KDR⁺ EPCs are commonly reported in the literature and CD34⁺/CD133⁺/KDR⁺ EPCs are rare in circulation but highly specific for endothelial lineage. HIV-infected (HIV+) adults have chronic inflammation and increased CVD risk, but the relationship between CVD, vascular inflammation, and EPCs in HIV remains unclear. In a pilot study, EPCs were measured in 57 HIV+ men [≥50 years old, HIV-1 RNA <50 copies/ml on antiretroviral therapy (ART)] by real-time flow cytometry using cellular immaturity (CD34 and/or CD133) and endothelial commitment (KDR) markers. Fasting inflammatory biomarker levels were measured by ELISA. Median age was 57 years; CD4⁺ T lymphocyte count was 570 cells/mm³. Prevalent CVD risk factors included 16% diabetes, 28% hypertension, 53% dyslipidemia, and 33% smoking. Median (interquartile range) EPC values were CD34⁺/KDR⁺ 0.1 (0.0-0.9) cells/10⁵ peripheral blood mononuclear cells (PBMCs) and CD34⁺/CD133⁺/KDR⁺ 0.1 (0.0-0.9) cells/10⁵ PBMCs. We observed a high prevalence of undetectable CD34⁺/KDR⁺ (40%) and CD34⁺/CD133⁺/KDR⁺ EPCs (44%). Men with undetectable EPCs were more likely to have ≥2 CVD risk factors, lower interleukin-6 (IL-6), and higher sCD163 levels. In these older HIV+ men on suppressive ART, CD34⁺/KDR⁺ and CD34⁺/CD133⁺/KDR⁺ EPC levels were low and often undetectable. Undetectable EPC levels were associated with greater CVD risk factor burden, lower IL-6 (consistent with decreased EPC production stimulus), and higher sCD163 (consistent with monocyte activation and prior CVD associations) levels, suggesting a potential relationship between EPCs and atherosclerotic burden in this population.

Objective

We documented the prevalence, distribution, and correlates of hepatitis C virus (HCV) infection among urban homeless adults.

Methods

We sampled a community-based probability sample of 534 homeless adults from 41 shelters and meal programs in the Skid Row area of downtown Los Angeles, California. Participants were interviewed and tested for HCV, hepatitis B, and HIV. Outcomes included prevalence, distribution, and correlates of HCV infection; awareness of HCV positivity; and HCV counseling and treatment history.

Results

Overall, 26.7% of the sample tested HCV-positive and 4.0% tested HIV-positive. In logistic regression analysis, independent predictors of HCV infection for the total sample included older age, less education, prison history, and single- and multiple-drug injection. Among lifetime drug injectors, independent predictors of HCV infection included older age, prison history, and no history of intranasal cocaine use. Among reported non-injectors, predictors of HCV infection included older age, less education, use of non-injection drugs, and three or more tattoos. Sexual behaviors and snorting or smoking drugs had no independent relationship with HCV infection. Among HCV-infected adults, nearly half (46.1%) were unaware of their infection.

Conclusions

Despite the high prevalence of HCV infection, nearly half of the cases were hidden and few had ever received any HCV-related treatment. While injection drug use was the strongest independent predictor, patterns of injection drug use, non-injection drug use, prison stays, and multiple tattoos were also independent predictors of HCV. Findings suggest that urgent interventions are needed to screen, counsel, and treat urban homeless adults for HCV infection.