Non-invasive assessment of microvascular dysfunction in patients with microvascular angina.

Background: We aimed to evaluate the microvascular function in patients with microvascular angina (MVA) by assessing 1) the endothelial glycocalyx barrier properties using sublingual microscopy, and 2) the myocardial perfusion reserve using cardiovascular magnetic resonance (CMR) imaging.

Methods: Sublingual microscopy was performed in 13 MVA patients (angina pectoris, ST-depression on treadmill testing, normal coronary angiogram) and compared with 2 control groups of 13 volunteers and 14 patients with known obstructive coronary artery disease (CAD). To test the glycocalyx-mediated microvascular responsiveness, the erythrocyte perfused boundary region (PBR) was assessed at baseline and after nitroglycerin challenge.

Metformin and sulodexide restore cardiac microvascular perfusion capacity in diet-induced obese rats.

Background: Disturbances in coronary microcirculatory function, such as the endothelial glycocalyx, are early hallmarks in the development of obesity and insulin resistance. Accordingly, in the present study myocardial microcirculatory perfusion during rest and stress was assessed following metformin or sulodexide therapy in a rat model of diet-induced obesity. Additionally, the effect of degradation of the glycocalyx on myocardial perfusion was assessed in chow-fed rats.

Early impairment of coronary microvascular perfusion capacity in rats on a high fat diet.

Background: It remains to be established if, and to what extent, the coronary microcirculation becomes compromised during the development of obesity and insulin resistance. Recent studies suggest that changes in endothelial glycocalyx properties contribute to microvascular dysfunction under (pre-)diabetic conditions. Accordingly, early effects of diet-induced obesity on myocardial perfusion and function were studied in rats under baseline and hyperaemic conditions.

Effects of two weeks of metformin treatment on whole-body glycocalyx barrier properties in db/db mice.

Background: The anti-diabetic drug metformin has been demonstrated to exert a protective effect against vascular complications in diabetes independent of its glucose lowering action. Since the endothelial glycocalyx has been indicated to have important vasculoprotective properties and to be vulnerable to degradation by hyperglycemic conditions, we evaluated in the current study the effect of short-term metformin treatment on whole-body glycocalyx barrier properties in a mouse model of non-insulin dependent diabetes mellitus (db/db mouse).

Methods: Glycocalyx barrier properties were measured in an acute experiment in three groups of mice: 1) db/db mice without treatment serving as controls, 2) db/db mice which received metformin for two weeks in the drinking water serving as experimental group, and 3) C57Bl/6 mice serving as reference group.

Whole-body recruitment of glycocalyx volume during intravenous adenosine infusion.

Adenosine-mediated recruitment of microvascular volume in heart and muscle has been suggested to include, in addition to vasodilation of resistance vessels, an increased accessibility of the endothelial glycocalyx for flowing plasma as a result of an impairment of its barrier properties. The aim of the current study was to investigate the effect of systemic intravenous administration of adenosine on the glycocalyx-dependent exclusion of circulating blood at a whole-body level. In anesthetized goats (N = 6), systemic blood-excluded glycocalyx volume was measured by comparing the intravascular distribution volume of the suggested glycocalyx accessible tracer dextrans with a molecular weight of 40 kDa (Dex-40) to that of circulating plasma, derived from the dilution of labeled red blood cells and large vessel hematocrit.

Real-time subject-specific analyses of dynamic internal tissue loads in the residual limb of transtibial amputees.

Transtibial amputation (TTA) prosthetic-users may risk the integrity of their residuum while trying to maintain everyday activities. Compression of the muscle flap between the truncated bones and the prosthetic socket may cause pressure ulcers and deep tissue injury (DTI). We hypothesize that mechanical stresses in the muscle flap are higher when walking over complex terrains than during plane gait, and so, the residuum could be at risk for DTI when walking over these terrains.