Abstract
Diabetes mellitus is a risk factor for cardiovascular disease; however, the mechanisms through which diabetes impairs homeostasis of the vasculature have not been completely elucidated. The endothelium interacts with circulating blood through the surface glycocalyx layer, which serves as a mechanosensor/transducer of fluid shear forces leading to biomolecular responses. Atherosclerosis localizes typically in regions of low or disturbed shear stress, but in diabetics, the distribution is more diffuse, suggesting that there is a fundamental difference in the way cells sense shear forces. In the present study, we examined the effect of hyperglycemia on mechanotranduction in bovine aortic endothelial cells (BAEC). After six days in high glucose media, we observed a decrease in heparan sulfate content coincident with a significant attenuation of the shear-induced hydraulic conductivity response, lower activation of eNOS after exposure to shear, and reduced cell alignment with shear stress. These studies are consistent with a diabetes-induced change to the glycocalyx altering endothelial response to shear stress that could affect the distribution of atherosclerotic plaques.
Highlights
Hyperglycemia is a characteristic feature of type 1 and type 2 diabetes that has been long associated with both micro and macrovascular dysfunction [1]
The baseline values for Lp for normal vs. high glucose were not significantly different from one another (3.826102760.57 cm/s/cm H2O vs. 4.716102760.65 cm/s/ cm H2O, p = 0.34). Both values of the baseline Lp were within the normal ranges that have been reported for bovine aortic endothelial cells (BAEC) in previous studies [20,24,25]
These observations have motivated our study of the effects of hyperglycemia on mechanosensing
Summary
Hyperglycemia is a characteristic feature of type 1 and type 2 diabetes that has been long associated with both micro and macrovascular dysfunction [1] Factors such as dyslipidemia, hyperinsulinemia, and hypertension together with endothelial dysfunction interact during the progression of the disease. The interaction between blood flow and the endothelium is a result of soluble factors, and includes the mechanosensing of shear forces that are exerted by blood flow [3]. This sensing enables the endothelium to strictly and acutely enforce vasoregulation through the production of vasodilators such as nitric oxide (NO) and prostacyclin (PGI2) and vasoconstrictors such as endothelin (ET) [4]. Shear forces affect the endothelial transport barrier through regulation of apoptosis and mitosis rates that control the leaky junctions that influence LDL transport [5,6] as well as through hydraulic conductivity (Lp) whose shear response is mediated by the glycocalyx (GCX) [7]
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