The coronary transfilter co-culture unit: an in vitro model for cellular and molecular studies of human coronary restenosis

Objective: The lack of reliable animal models for the prediction of human p ostangioplasty restenosis makes the development of complex human in vitro m odels necessary. Human coronary transfilter co-culture units (TCC-units) mi mic the inner parts of coronary arteries and allow in vitro investigations of the complex cellular interactions after vascular injury. Methods: Smooth muscle cells of the human coronary media (HCMSMC, Clonetics , Cell System, Remagen, Germany) and human coronary endothelial cells (HCAE C, Clonetics) were cultured on both sides of polycarbonate filter membranes . Through the filter pores direct interactions between HCMSMC and HCAEC are possible, the size of the filter pores enables cells to move from one side of the filter to the of her side. After 14 days in co-culture filter membr anes of the TCC-units were fixed with 4% paraformaldehyde, Bromodeoxyuridin e (BrdU), a thymidine analogue, was added to the culture media 18 h prior t o fixation in order to analyse proliferative activity, Semithin sections (4 mu m) were processed for toluidine blue and immunohistological staining, S ections of the filter membranes were investigated and the number of BrdU po sitive cells was calculated in percent of the total amount of cells. Results: After a period of 14 days one continuous layer of cells has grown on the HCAEC-side of the filters, 3-5 layers of cells were found on the HCM SMC-side. HCAEC and HCMSMC on the filters were identified by von Willebrand factor respectively smooth muscle alpha-actin antigen immunofluorescence. At day 15 only 1.94 +/- 0.72% (x SDn-1) of the cells on the HCMSMC side of the TCC-units were BrdU-positive. Conclusion: Coronary TCC-units are a tool for in vitro investigations of th e complex cellular and molecular interactions in human coronary arteries af ter vascular injury.