Paper Title
Butyrate Induced Icam-1, Cathepsin B, Vimentin And N-Cadherin Secretion/Expression Of Vascular Endothelial Cells

Abstract
Butyric acid is generated by oral and intestinal microorganisms duringmetabolism of fibrous food. Localized concentration of butyric acid in periodontal pockets can reach even 24 mM. Butyric acid has diverse biological effects including anti-carcinogenic, prevention of obesity, and insulin resistance etc. But whether high concentration of butyric acid in periodontal pocket may affect periodontal/periapical wound healing responses and systemic cardiovascular health is an interesting issue. However, little is known about whether butyric acid may have effects on various mediators’ release and mesenchymal transition of vascular endothelial cells, that plays important role in wound healing, angiogenesis, atherosclerosis, and cardiovascular diseases. In this study, EAHY endothelial cells were exposed to various concentrations of butyrate for 3 days. Morphology was taken under microscope. Cell viability was determined by MTT assay. Culture medium was collected for analysis. Effect of butyrate on various inflammatory mediators’ release into culture mediumof EAHY endothelial cells was analyzed by enzyme linked immunosorbant assay (ELISA). Cellular proteins were collected for western blotting analysis. Butyrate (1-16 mM) showed no marked cytotoxicity to EAHY endothelial cells after 3 days of exposure. Butyrate stimulated sICAM-1 and cathepsin B secretion of endothelial cells. But it inhibited endothelin, uPA and osteocalcin production of endothelial cells. Butyrate also stimulated osteoactivin (GPNMB) secretion. Morphologically, endothelial cells are cuboid or polygonal appearance. After exposure to butyrate for 3 days, endothelial cells became fibroblast-like spindle shaped in appearance. Moreover, an increased expression of N-cadherin and vimentin (two endothelial-mesenchymal transition markers) in endothelial cells after exposure to butyrate was noted. These results indicate that exposure of endothelium to butyric acid may potentially affect inflammatory effect, vascular calcification and endothelial-mesenchymal transition. These events may possibly contribute to vascular inflammation, healing, fibrosis,atherosclerosis, cardiovascular and periodontal/periapical diseases. (This study is supported by grants from Ministry of Science and Technology, Taiwan, ROC; Chang Gung Memorial Hospital, CMRP, Taiwan).