Surgical preparation induces injury and promotes smooth muscle cell proliferation in a culture of human saphenous vein.

OBJECTIVE

The aim was to investigate the influence of vessel wall injury, incurred during routine vein preparation, on smooth muscle cell proliferation.

METHODS

A newly developed quantitative organ culture was used, in which segments of human saphenous vein were cultured in medium containing 30% fetal bovine serum and 1 microCi.ml-1 of [3H]thymidine for up to 14 d. Endothelial integrity was measured by scanning electron microscopy and medial cell viability by adenine nucleotide concentrations. Cell proliferation was measured by DNA concentration, global incorporation of [3H]thymidine, and by counting labelled cells in autoradiographs of transverse sections.

RESULTS

Surgical preparation led to endothelial injury and reduced adenine triphosphate concentration by 60%. Surgically prepared veins also suffered a significant decline in DNA concentration during culture, which implied that injury led to cell necrosis. Surgically prepared veins showed 2.1- and 2.7-fold greater global incorporation of [3H]thymidine than freshly isolated veins after 7 and 14 d in culture, respectively, which corresponded with a 23-fold and 11-fold greater abundance of thymidine labelled cells in the medial layer. Intimal thickening and the numbers of total and thymidine labelled cells in the intimal layer were similar.

CONCLUSIONS

The data show that injury incurred during routine surgical preparation is associated with enhanced medial smooth muscle cell proliferation. The effect of injury was most probably to permit an increased response of medial smooth muscle cells to serum derived mitogens.