| Summary: | 碩士 === 中興大學 === 生命科學院碩士在職專班 === 95 === Obesity, the excessive accumulation of fat, is a risk factor for development of metabolic syndrome. The adipose tissue itself has proven to be an important endocrine organ, secreting several hormones and cytokines, usually referred as adipocytokines or adipokines. Visfatin can bind to and activate the insulin receptor, exerting insulin mimetic effects both in vitro and in vivo. In addition, visfatin, found to identical to pre-B-cell colony-enhancing factor (PBEF), a novel inflammatory cytokine that plays a requisite role in the delayed neutrophil apoptosis , and it levels in blood levels have been reported higher in subjects with obesity and/or type 2 diabetes mellitus. It is currently unclear the pathophysiological role of visfatin and it association with endothelial dysfunction related inflammatory and adhesion molecule expression has been largely unexplored.
Primary human umbilical vein endothelial cells (HUVECs) pretreated with visfatin (1, 10, 50 ng/ml) were used to study the relationship between visfatin and endothelium dysfunction. Expression of cytokine (IL-6 and IL-8) and adhesion molecules (VCAM-1 and E-selectin) affected by visfatin were investigated by real-time PCR and ELISA. Activity of NF-κB was examined by electrophoretic mobility shift assay (EMSA).At a visfatin concentration of 50 ng/ml, significant increases in IL-6 (2.72 folds), IL-8 (1.93 folds), ICAM-1 (2.96 folds), VCAM-1 (3.97 folds) and E-selectin (2.80 folds) gene expression (all p<0.05) along with increased IL-6 (1.76 folds), IL-8 (1.23 folds) and sE-selectin (1.78 folds) protein levels (all p<0.05) in the conditioned medium were detected. Visfatin significantly increased ICAM-1 (1.11 folds) expression on 10 ng/ml, and VCAM-1 (1.06 folds) expression on 50 ng/ml detected by flow cytometry. Results from EMSA confirmed that visfatin (10, 50 ng/ml) increased DNA binding activity of NF-κB (1.56 folds, 1.38 folds respectively) (p<0.05). In addition, increased human monocyte cell line THP-1 attaching to HUVECs when pretreated with visfatin (10, 50 ng/ml) was also demonstrated(1.22 folds, 1.22 folds respectively) (p<0.05).
We demonstrated that visfatin increased inflammatory and adhesion molecule expression, at least partly via up-regulated of NF-κB activity, that might contribute to increased endothelial dysfunction. In addition, visfatin enhanced THP-1 adherence to HUVECs. Our findings provide direct evidence that visfatin causes endothelial dysfunction, which may help establish a link between obesity and cardiovascular disease, as well as a novel approach to target the development of new therapeutic strategies.
|
|---|
