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- Chai, W. D., et al.
(författare)
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Inhibiting myeloperoxidase prevents onset and reverses established high-fat diet-induced microvascular insulin resistance
- 2019
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Ingår i: American Journal of Physiology-Endocrinology and Metabolism. - : American Physiological Society. - 0193-1849 .- 1522-1555. ; 317:6
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Tidskriftsartikel (refereegranskat)abstract
- A high-fat diet (HFD) can rapidly recruit neutrophils to insulin target tissues and within days induce microvascular insulin resistance (IR). Myeloperoxidase (MPO) is highly enriched in neutrophils, can inhibit nitric oxide-mediated vasorelaxation in vitro and is associated with increased cardiovascular disease risk. AZD5904 irreversibly inhibits MPO and in human clinical trials. MPO knockout, or chemical inhibition, blunts HFD-induced metabolic IR in mice. Whether MPO affects microvascular IR or muscle metabolic insulin sensitivity in vivo is unknown. We used contrast-enhanced ultrasound and the euglycemic insulin clamp to test whether inhibiting MPO could prevent the development or reverse established HFD-induced metabolic and/or microvascular IR in Sprague-Dawley rats. Two weeks of HFD feeding blocked insulin-ediated skeletal muscle capillary recruitment, inhibited glucose utilization, and insulin signaling to muscle. Continuous subcutaneous AZD5904 infusion during the 2 wk selectively blocked HFD's microvascular effect. Furthermore, AZD5904 infusion during the last 2 of 4 wk of HFD feeding restored microvascular insulin sensitivity but not metabolic IR. We conclude that inhibiting MPO selectively improves vascular IR. This selective microvascular effect may connote a therapeutic potential for MPO inhibition in the prevention of vascular disease/dysfunction seen in IR humans.
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- Jahn, L. A., et al.
(författare)
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Insulin Enhances Endothelial Function Throughout the Arterial Tree in Healthy But Not Metabolic Syndrome Subjects
- 2016
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Ingår i: Journal of Clinical Endocrinology & Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 101:3, s. 1198-1206
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Tidskriftsartikel (refereegranskat)abstract
- Context: Insulin reportedly impairs endothelial function in conduit arteries but improves it in resistance and microvascular arterioles in healthy humans. No studies have assessed endothelial function at three arterial levels in healthy or metabolic syndrome (METSYN) subjects. Objective: The objective of the study was to compare endothelial responsiveness of conduit arteries, resistance, and microvascular arterioles to insulin in healthy and METSYN subjects. Design: We assessed conduit, resistance, and microvascular arterial function in the postabsorptive and postprandial states and during euglycemic hyperinsulinemia (insulin clamp). Participants: Age-matched healthy and METSYN subjects participated in the study. Interventions: We used brachial flow-mediated dilation, forearm postischemic flow velocity, and contrast-enhanced ultrasound to assess the conduit artery, resistance arteriole, and microvascular arteriolar endothelial function, respectively. We also assessed the conduit artery stiffness (pulse wave velocity and augmentation index) and measured the plasma concentrations of 92 cardiovascular disease biomarkers at baseline and after the clamp. Results: Postabsorptive and postprandial endothelial function was similar in controls and METSYN in all tested vessels. METSYN subjects were metabolically insulin resistant (P < .005). In controls, but not METSYN subjects, during euglycemic hyperinsulinemia, endothelial function improved at each level of arterial vasculature (P < .05 or less for each). Conduit vessel stiffness (pulse wave velocity) was increased in the METSYN group. Twelve of 92 biomarkers differed at baseline (P < .001) and remained different at the end of the insulin clamp. Conclusions: We conclude that insulin enhances arterial endothelial function in health but not in METSYN, and this vascular insulin resistance may underlie its increased cardiovascular disease risk.
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