Pericytes Augment the Capillary Barrier in in Vitro Cocultures

• Published in: The Journal of surgical research 2001-05, Vol.97 (1), p.85-91
• Main Authors: Dente, Christopher J, Steffes, Christopher P, Speyer, Cecilia, Tyburski, James G
• Format: Article
• Language: English
• Subjects: albumin permeability; Albumins - metabolism; Animals; Biological and medical sciences; Blood and lymphatic vessels; Capillary Permeability; Cardiology. Vascular system; Cattle; Cell Culture Techniques - methods; Cell Division; Cells, Cultured; cocultures; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Electric Impedance; electrical resistance; endothelial cells; Endothelium, Vascular - cytology; Endothelium, Vascular - physiology; in vitro; Kinetics; Medical sciences; microvascular permeability; pericytes; Pericytes - physiology; tissue culture
• ISSN: 0022-4804; 1095-8673
• DOI: 10.1006/jsre.2001.6117

Most in vitro studies of capillary permeability focus on endothelial cell (MVEC) monolayers and ignore the second cell that forms the capillary wall: the microvascular pericyte (PC). We describe a model to study the permeability characteristics of MVEC, PC, and MVEC:PC cocultures. Methods. Semipermeable culture inserts were coated with collagen and then plated with early passage bovine pulmonary MVEC. On Day 3, bovine pulmonary PC were added at concentrations to approximate MVEC:PC ratios of 1:1, 5:1, and 10:1. Electrical resistance was measured on subsequent days and fluorescently labeled (FITC) albumin was used in a permeability assay to calculate an albumin clearance for each culture. Results. The results for electrical resistance measurements and albumin assays showed a similar pattern. Resistance for endothelial cell monolayers was significantly higher and albumin permeability was significantly lower than that of controls. Addition of pericytes at a 10:1 and 5:1 ratios increased the permeability barrier compared to endothelial cells alone, although these cultures were not significantly different from one another. Cocultures at a 1:1 ratio had the best barrier, significantly better than all other cultures. Conclusions. Endothelial cell monolayers are an inadequate model of the microcirculation. As PC form a key component of the capillary wall in vivo and as addition of PC to MVEC monolayers in vitro, optimally at a 1:1 ratio, increase their barrier effect to large and small molecules, we believe it is necessary to include both cells in future in vitro studies.