Effects of Shear Forces and Pressure on Blood Vessel Function and Metabolism in a Perfusion Bioreactor

Abstract

Bovine saphenous veins (BSV) were incubated in a perfusion bioreactor to study vessel wall metabolism and wall structure under tissue engineering conditions. Group 1 vessels were perfused for 4 or 8 days. The viscosity of the medium was increased to that of blood in group 2.Group 3 vessels were additionally strained with luminal pressure. Groups 1-d through 3-d were similar except that BSV were endothelium-denuded before perfusion. Groups 1-a through 3-a used native vessels at elevated flow rates. Group 3 vessels responded significantly better to noradrenaline on day 4, whereas denuded vessels showed attenuated responses (p<0.001). Tetrazolium dye reduction did not depend on perfusion conditions or time except for denuded vessels. pO 2 gradients across the vessels were independent of time and significantly higher in group 2 (p<0.001). BSV converted glucose stoichiometrically to lactate except vessels of groups 3, 1-d, and 3-d which released more lactate than glucose could supply (p<0.001). Group 1 vessels as well as all vessels perfused with elevated flow rates showed a loss of endothelial cells after 4 days, whereas group 2 and 3 vessels retained most of the endothelium. These data suggest that vessel metabolism was not limited by oxygen supply. Shear forces did not affect glucose metabolism but increased oxygen consumption and endothelial cell survival. Luminal pressure caused the utilization of energy sources other than glucose, as long as the endothelium was intact. Therefore, vessel metabolism needs to be monitored during tissue engineering procedures which challenge the constructs with mechanical stimuli.

A compact and automatedex vivovessel culture system for the pulsatile pressure conditioning of human saphenous veins

“…Further, the silicone tubing length was dimensioned according to an analytical model (Orr and Burg, ) based on the balance between oxygen depletion (vessel cell metabolism) or replenishment (silicone tubing) in order to guarantee appropriate vessel oxygenation. Briefly, the oxygen consumption of native vascular tissue was set to 3.57 × 10 –3 ml O 2 /min, assuming an oxygen demand of 3.57 × 10 –6 ml O 2 /(min kg) and considering the mass of a SV graft to be about 1 g (Hoenicka et al ., ). In this condition, the necessary silicone tubing length was found to be at least 250 cm.…”

Nanomechanics to Drive Stem Cells in Injured Tissues: Insights from Current Research and Future Perspectives

“…The mechanotransduction is a critical process that can drive many physiological and diseaserelated cellular events, including cell death [11], metabolism [12], migration [13], proliferation, and differentiation [14]; further, the magnitude of sensing is often related to the type and direction of mechanical forces applied. Mechanosensitive feedback underlies many tissue processes at a cellular level, including tissue morphogenesis and homeostasis, angiogenesis, and wound healing.…”

Impact of short‐term perfusion on cell retention for 3D bioconstruct development

“…Dynamic culture can affect cell function from various aspects such as metabolism, cell number, and extracellular matrix assembly 5, 6. Tremendous studies in literature have investigated the cell population change under dynamic culture for 3D construct development 7–10.…”