Interaction between pericytes and endothelial cell of foetal capillaries in hypertensive placentae

Abstract

INTRODUCTION : Pericytes and endothelial cells are known to possess direct contacts in many parts of the vascular tree. Pericytes are known to have modulating effects on endothelial cell growth and differentiation. It is possible that some pericytes are a source of new endothelial cell. OBJECTIVES : Information regarding the ultrastructural changes of foetal capillaries of hypertensive placentae is lacking. Therefore we studied the foetal capillaries of hypertensive placentae to ascertain any significant ultrastructural interaction between pericytes. endothelial cells and basement membrane. METHOD : Placental tissue from 15 pregnant mothers with a blood pressure of 140/90 or more and 10 normal mothers who had normal full term deliveries were studied. Fresh placentae were examined and 2mm sized pieces were taken from central foetal and fixed in 2% gluteraldehyde for eletron microscopic studies. RESULTS : All hypertensive placentae showed a number of pericytic processes, which was significantly higher than in normal placentae. (P<0.001). Both frequency and complexity of direct connections between endothelial cells and pericytes appear to be increased in foetal capi 1 laries of hypertensive placentae . Basement membranes of foetal capillaries in 9 hypertensive placentae showed marked thickening. CONCLUSIONS : There was complexed interaction between endothelial cells and pericytes of foetal capillaries of hypertensive placentae.