THE EFFECT OF RADIOGRAPHIC CONTRAST-MEDIA ON HUMAN VASCULAR SMOOTH-MUSCLE CELLS

The relation between intravascular radiographic contrast media (RCM) a nd myointimal hyperplasia after percutaneous transluminal angioplasty is not known. We have: investigated the cytotoxic effects of RCM on hu man vascular smooth muscle cells (VSMCs) and their effect on the growt h of these cells. The cytotoxic effects of RCM were studied using huma n VSMCs. The cells after being grown to confluency were exposed for 60 min to 250 mgI ml(-1) of diatrizoate, ioxaglate, iopromide, iotrolan and saturated mannitol solutions. The control group was treated with o nly 15% fetal calf serum (FCS) containing medium. The viability of the cells was examined using the trypan blue exclusion test. The effect o f RCM on growth was assessed by exposing the VSMCs after growth arrest , for either 15 or 60 min to 250 mgI ml(-1) of diatrozoate, ioxaglate? iopromide, iotrolan and saturated mannitol solution. There was net si gnificant change in the viability of the VSMCs after 60 min exposure t o iopromide. iotrolan, saturated mannitol solution, and after 15 min e xposure to diatrizoate or ioxaglate. After exposure to diatrizoate or ioxaglate for 60 min, 16.5 +/- 2.2% or 9.2 +/- 2.6% dead cells were fo und, respectively (p < 0.05 versus control). In the growth assay of VS MCs, diatrizoate, ioxaglate and saturated mannitol solutions reduced t he growth rate (p < 0.05 versus control). No significant change was ob served with iopromide and iotrolan. In conclusion, ionic RCM have cyto toxic and cytostatic effects on VSMCs while nonionic media have no eff ects. There is no direct stimulatory effect of contrast media on the g rowth of VSMCs. The cytotoxic and cytostatic effects of contrast media seems to be bath osmolality and chemotoxicity dependent. Low osmolar non-ionic RCM are not likely to contribute to the mechanisms responsib le for myointimal hyperplasia after angioplasty.