High-Glucose-Altered Endothelial Cell Function Involves Both Disruption of Cell-to-Cell Connection and Enhancement of Force Development

Abstract

Vascular endothelial cells (ECs), which regulate vascular tonus, serve as a barrier at the interface of vascular tissue. It is generally believed that alteration of this barrier is correlated with diabetic complications; however, a detailed mechanism has not been elucidated. This study examined alteration of bovine arterial EC functions stimulated by a thromboxane A 2 analog (9,11-dideoxy-11␣,9␣-epoxymethano prostaglandin F 2␣ ; U46619) under normal and high-glucose (HG) conditions. U46619 treatment increased EC layer permeability in a timeand dose-dependent fashion. This response initially disrupted calcium-dependent EC-to-EC connections, namely, vascular endothelial cadherin (VE-CaD). Thereafter, EC force development in association with morphological changes was detected employing a reconstituted EC fiber technique, resulting in paracellular hole formation in the EC layer. Thus, we confirmed that U46619-induced enhancement of EC layer permeability involves these sequential steps. Similar trials were performed using a concentration twice that of normal glucose (22.2 mM glucose for 48 h). This treatment significantly enhanced U46619-induced EC layer permeability; furthermore, increases in both rate of VE-CaD disruption and EC fiber contraction were evident. Inhibition of calcium-independent protein kinase C and diacylglycerol kinase indicated that the glucose-dependent increase in VE-CaD disruption was mediated by a calcium-independent mechanism. Moreover, EC contraction was regulated by a typical calcium-independent pathway associated with rho kinase and actin stress fiber. Contraction was also enhanced under HG conditions. This investigation revealed that glucosedependent enhancement of EC layer permeability is related to increases in VE-CaD disruption and EC contraction. Increases in both parameters were mediated by alteration of a calciumindependent pathway.

Glucose-Dependent Enhancement of Diabetic Bladder Contraction Is Associated with a Rho Kinase-Regulated Protein Kinase C Pathway

“…It was recently reported that HG treatment enhances rho kinase activity via increases in rho A level in diabetic aorta (Akiyama et al, 2008). We suggested previously that HG-induced vascular endothelial cell dysfunctions participate in glucosedependent rho kinase activation (Nobe et al, 2006). A similar relationship between glucose and rho kinase was predicted with respect to the diabetic bladder smooth muscle dysfunction under HG conditions; however, a critical target of the enhanced extracellular glucose in relation to rho kinase activity is unknown.…”

Endothelial cells' biophysical, biochemical, and chromosomal aberrancies in high‐glucose condition within the diabetic range

“…On the other hand, we found that the disruption of EC‐EC tight confluent connectivity and TEER reduction were induced 72 hours after exposure to HGC . The reason for this finding could be that disrupted calcium dependence of EC‐EC connections via VE‐cadherin, morphological rearrangement, and paracellular gap formation was induced after exposure to HGC . The other possible mechanisms include the previously reported protein kinase C elevation and focal adhesion kinase phosphorylation impairment in HGC, which in turn can lead to deformed actin alignment .…”

“…17,50 The reason for this finding could be that disrupted calcium dependence of EC-EC connections via VE-cadherin, morphological rearrangement, and paracellular gap formation was induced after exposure to HGC. 51 The other possible mechanisms include the previously reported protein kinase C elevation and focal adhesion kinase phosphorylation impairment in HGC, which in turn can lead to deformed actin alignment. 52 In line with previous studies, we showed an enhanced expression of both VE-cadherin and ZO-1 at all-time points (especially at 72 hours) in the cells under HGC.…”

Resveratrol Ameliorates High Glucose and High-Fat/Sucrose Diet-Induced Vascular Hyperpermeability Involving Cav-1/eNOS Regulation

“…Vascular hyperpermeability is one of the manifestations of endothelial dysfunction [1]. Evidence demonstrated that endothelial dysfunction is recognized as initial step in the atherosclerotic process and is well advanced in diabetes [2].…”