Single-leg exercise training augments in vivo skeletal muscle oxidative flux and vascular content and function in adults with type 2 diabetes.

KEY POINTS: People with type 2 diabetes (T2D) have impaired skeletal muscle oxidative flux due to limited oxygen delivery. In the current study, this impairment in oxidative flux in people with T2D was abrogated with a single-leg exercise training protocol. Additionally, single-leg exercise training increased skeletal muscle CD31 content, calf blood flow and state 4 mitochondrial respiration in all participants. ABSTRACT: Cardiorespiratory fitness is impaired in type 2 diabetes (T2D), conferring significant cardiovascular risk in this population; interventions are needed. Previously, we reported that a T2D-associated decrement in skeletal muscle oxidative flux is ameliorated with acute use of supplemental oxygen, suggesting that skeletal muscle oxygenation is rate-limiting to in vivo mitochondrial oxidative flux during exercise in T2D. We hypothesized that single-leg exercise training (SLET) would improve the T2D-specific impairment in in vivo mitochondrial oxidative flux during exercise. Adults with (n = 19) and without T2D (n = 22) with similar body mass indexes and levels of physical activity participated in two weeks of SLET. Following SLET, in vivo oxidative flux measured by 31 P-MRS increased in participants with T2D, but not people without T2D, measured by the increase in initial phosphocreatine synthesis (P = 0.0455 for the group × exercise interaction) and maximum rate of oxidative ATP synthesis (P = 0.0286 for the interaction). Additionally, oxidative phosphorylation increased in all participants with SLET (P = 0.0209). After SLET, there was no effect of supplemental oxygen on any of the in vivo oxidative flux measurements in either group (P > 0.02), consistent with resolution of the T2D-associated oxygen limitation previously observed at baseline in subjects with T2D. State 4 mitochondrial respiration also improved in muscle fibres ex vivo. Skeletal muscle vasculature content and calf blood flow increased in all participants with SLET (P < 0.0040); oxygen extraction in the calf increased only in T2D (P = 0.0461). SLET resolves the T2D-associated impairment of skeletal muscle in vivo mitochondrial oxidative flux potentially through improved effective blood flow/oxygen delivery.

Carotid magnetic resonance imaging in persons living with HIV and 10-year atherosclerotic cardiovascular disease risk score.

BACKGROUND: Both traditional and HIV-specific risk factors contribute to greater incidence of cardiovascular disease in persons living with HIV (PLWH). Using state-of-the-art, high-resolution magnetic resonance (MR) imaging of the common carotid arteries, this study aimed to evaluate the relationship between carotid vessel wall thickness (c-VWT) and atherosclerotic cardiovascular disease (ASCVD) risk score in PLWH. METHODS: Cross-sectional determinations of c-VWT using MR imaging in virally suppressed PLWH without known cardiovascular disease (n=32) and matched controls (n=13) were completed. Clinical data, including ASCVD risk and c-VWT, were compared between groups and regression analyses performed to identify predictors of c-VWT. RESULTS: PLWH had significantly higher c-VWT (1.15 ±0.11 mm versus 1.08 ±0.08 mm; P=0.02) as well as higher diastolic blood pressure compared to controls, but exhibited no differences in 10-year ASCVD risk score, systolic blood pressure or smoking. Ten-year ASCVD risk score (r=0.53, P-value =0.0002), age (r=0.30, P-value <0.05), triglycerides (r=0.33, P-value =0.03) and waist circumference (r=0.36, P-value =0.02) were significantly associated with increased c-VWT. Among PLWH, c-VWT did not differ by protease inhibitor use. In a multivariate regression analysis, ASCVD risk score was the only variable significantly associated with c-VWT (P-value =0.02), whereas, HIV status was not. CONCLUSIONS: In this cross-sectional study MR imaging demonstrated that c-VWT, a known marker for CVD risk, was increased in PLWH relative to controls, and that 10-year ASCVD risk was closely related to c-VWT, independent of HIV infection. Our data suggest that traditional cardiovascular disease risk factors in PLWH are adequately captured in the ASCVD risk score which was closely associated with subclinical carotid disease.

Indole-based allosteric inhibitors of HIV-1 integrase.

Employing a scaffold hopping approach, a series of allosteric HIV-1 integrase (IN) inhibitors (ALLINIs) have been synthesized based on an indole scaffold. These compounds incorporate the key elements utilized in quinoline-based ALLINIs for binding to the IN dimer interface at the principal LEDGF/p75 binding pocket. The most potent of these compounds displayed good activity in the LEDGF/p75 dependent integration assay (IC50=4.5µM) and, as predicted based on the geometry of the five- versus six-membered ring, retained activity against the A128T IN mutant that confers resistance to many quinoline-based ALLINIs.