INCREASED AMBIENT-PRESSURE STIMULATES PROLIFERATION AND MORPHOLOGIC CHANGES IN CULTURED ENDOTHELIAL-CELLS

Very little is known about the effects of pressure within the vascular system on EC phenotype. To study this, bovine aortic EC were seeded o n rat type I collagen plates (2,000/cm2) and allowed to attach for 24 hours. The cells were exposed to either atmospheric, 40, 80, or 1 20 m m Hg pressure by placing them in a plexiglass pressure chamber loaded with 5% CO2/air and maintained at 37-degrees-C inside an incubator. Ch amber pressure was continuously monitored with an amplified voltage tr ansducer connected to a digital monitor. EC were maintained in DMEM su pplemented with 10% calf serum and substrates for up to 9 days. The re sults indicate that EC proliferation is influenced by their ambient pr essure. EC subjected in vitro to pressures comparable to mean systemic blood pressures had a significant increase in cell number compared to EC exposed to atmospheric pressures. EC were elongated and appeared t o align randomly. We hypothesize that the systemic pressure which the endothelium is exposed to in vivo may have a significant regulatory in fluence on the ability of the endothelium to proliferate which may aff ect the endothelial cell response to injury. (C) 1994 Wiley-Liss, Inc.