Markers of microbial translocation predict hypertension in HIV-infected individuals.

OBJECTIVES: The aim of the study was to test the hypothesis that microbial translocation, quantified by levels of lipopolysaccharide (LPS) and subsequent monocyte activation [soluble (sCD14)], is associated with hypertension in HIV-infected individuals. METHODS: In this exploratory substudy, 42 patients were recruited from a larger, longitudinal HIV-infected cohort study on blood pressure. LPS and sCD14 levels were measured retrospectively at the time of nadir CD4 cell count, selecting untreated HIV-infected patients with both advanced immunodeficiency and preserved immunocompetence at the time of nadir. Patients with later sustained hypertension (n = 16) or normotension (n = 26) throughout the study were identified. LPS was analysed using the Limulus Amebocyte Lysate colorimetric assay (Lonza, Walkersville, MD) and sCD14 using an enzyme-linked immunosorbent assay (ELISA). Nonparametric statistical tests were applied. RESULTS: In the HIV-infected patients [median (interquartile range) age 42 (32-46) years; 79% male and 81% Caucasian], LPS and sCD14 levels were both negatively correlated with nadir CD4 cell count. Plasma levels of LPS (P < 0.001) and sCD14 (P = 0.024) were elevated in patients with later hypertension compared with patients with normotension. There was a stepwise increase in the number of patients with hypertension across tertiles of LPS (P = 0.001) and sCD14 (P = 0.007). Both LPS and sCD14 were independent predictors of elevated blood pressure after adjustment for age and gender. For each 10-unit increase in LPS (range 66-272 pg/ml), the increment in mean blood pressure in the first period of blood pressure recording was 0.86 (95% confidence interval 0.31-1.41) mmHg (P = 0.003). CONCLUSIONS: As LPS and sCD14 were both independently associated with elevated blood pressure, microbial translocation may be linked to the development of hypertension.

Association between HIV infection and attenuated diurnal blood pressure rhythm in untreated hypertensive individuals.

OBJECTIVE: Hypertensive cardiovascular complications are more closely associated with ambulatory blood pressure (ABP), particularly the attenuated diurnal blood pressure (BP) rhythm (i.e. a fall in systolic blood pressure <10% during the night compared with the day), than with casual BP. The aim of the study was to assess the ABP pattern in an HIV-infected cohort in which hypertension was newly diagnosed. METHODS: ABP over 24 h was compared between 77 newly diagnosed, untreated hypertensive HIV-positive individuals and 76 HIV-uninfected untreated hypertensive controls. RESULTS: More HIV-infected subjects had an attenuated ABP rhythm with a reduced nocturnal fall than HIV-negative hypertensive control subjects (60 vs. 33%, respectively; P=0.001). The dipping pattern was observed despite newly diagnosed hypertension, a low prevalence of microalbuminuria, and the absence of signs of overt kidney disease. Furthermore, the prevalence of nondipping in the HIV-infected subjects was independent of combination antiretroviral treatment. Multiple logistic regression analysis with dipping pattern as the dependent variable showed that HIV status was an independent predictor of nondipping BP [P=0.002; odds ratio (OR) 0.33; 95% confidence interval (CI) 0.17-0.66]; casual SBP (P=0.37; OR 1.001; 95% CI 0.99-1.04) and microalbuminuria (P=0.39; OR 1.56; 95% CI 0.57-4.28) were not associated with dipping pattern. CONCLUSIONS: The prevalence of a nondipping BP pattern in HIV-infected subjects with newly diagnosed hypertension who had not received antihypertensive treatment was high and significantly greater than in hypertensive control subjects.