ABSTRACT
Diabetes is associated with increased formation of advanced glycation end products (AGEs), which have been implicated in micro and macrovascular complications of diabetes. Our earlier reports showed proangiogenic effect of AGE-bovine serum albumin (BSA). In order to understand the mechanism of AGE-mediated angiogenesis, the possibility of involvement of peroxisome prolifeator activated receptor (PPAR) , a ligand activated transcription factor was examined. The angiogenic effect was studied in chick chorio allantoic membrane (CAM) and by analyzing angiogenic markers in human umbilical vein endothelial cells (HUVECs) in culture. The involvement of PPAR was investigated using synthetic PPAR agonist GW 1929 and antagonist GW 9662 and by RT-PCR. In CAM assay, PPAR antagonist GW 9662 reversed the AGE-induced effect on vascularity. In HUVECs in culture, GW 9662 reversed the effect of AGE-BSA and decreased the expression of CD 31, E-Selectin and VEGF. RT-PCR analysis showed that treatment with AGE-BSA caused upregulation of PPAR mRNA levels. The reversal of the effect of AGE on angiogenesis by treatment with PPAR antagonists and up-regulation of PPAR gene in HUVECs treated with AGE-BSA suggested the possible involvement of PPAR -dependent downstream pathway in mediating the angiogenic effect of AGE.
Subject(s)
Angiogenesis Inducing Agents/metabolism , Anilides/pharmacology , Animals , Platelet Endothelial Cell Adhesion Molecule-1/drug effects , Platelet Endothelial Cell Adhesion Molecule-1/metabolism , Benzophenones/pharmacology , Cells, Cultured , Chick Embryo , Chorioallantoic Membrane/drug effects , Chorioallantoic Membrane/metabolism , Diabetes Mellitus/metabolism , E-Selectin/metabolism , /pharmacology , Human Umbilical Vein Endothelial Cells/metabolism , PPAR gamma/antagonists & inhibitors , PPAR gamma/antagonists & inhibitors , PPAR gamma/drug effects , PPAR gamma/metabolism , RNA/drug effects , RNA/metabolism , Tyrosine/analogs & derivatives , Tyrosine/pharmacology , Vascular Endothelial Growth Factor A/drug effects , Vascular Endothelial Growth Factor A/metabolismABSTRACT
Biliary, ureteric and intestinal colic are extremely common clinical conditions associated with smooth muscle spasm. In the present study, antispasmodic activity was carried out against acetylcholine (10-640 ng/ml)-induced contractions on guinea pig ileum. Acetylcholine (10-640 ng/ml) induced concentration-dependent contraction of smooth muscle. Diclofenac, in varying concentration (9.4 x 10(-5) mol/l and 14.1 x 10(-5) mol/l) shifted the concentration response curve of acetylcholine to the right without suppressing the maximal response. However, in higher concentration diclofenac (18.9 x 10(-5) mol/l) blocked the response in an unsurmountable fashion. Further, analgin (11.09 x 10(-5), 16.63 x 10(-5) and 22.18 x 10(-5) mol/l) in equimolar concentrations did not alter the concentration response curve of acetylcholine, but in higher concentration analgin (44.36 x 10(-5) mol/l) also blocked the response in an unsurmountable fashion. Pitofenone (2.5 x 10(-6) mol/l) also, shifted the concentration response curve of acetylcholine to right in a parallel fashion with no change in maximal response. The present study confirms the potent antispasmodic activity of diclofenac-pitofenone combination in comparison to analgin-pitofenone in molar equivalent concentration (in comparison to diclofenac) against acetylcholine-induced contractions of guinea pig ileum.