Influence of Class I interferons on performance of vascular cells on stent material in vitro.

Purpose: Numerous reports suggest that Class 1 interferons (IFNs), particularly IFN-gamma, inhibit migration and proliferation of different types of human cells. The objective of the present study was to determine the effect of Class I IFNs on viability and growth characteristics of human aortic endothelial cells (ECs), smooth muscle cells (SMC) and fibroblasts (FBs) in vitro.

Methods: Stainless-steel (316-l) disks were coated with fibrin meshwork containing IFN-gamma or IFN-alpha. The discs and IFN embedded meshwork were incubated with human EC, SMC and FB, and then cultured, whereas control cells were seeded onto uncoated surfaces or plain fibrin meshwork. Concentrations of recombinant IFN varied from 5 to 20 ng/cm(2). Assessment of effect on cell viability, growth and attachment was performed utilizing Alamar Blue (AB) assay. Cell morphology was assessed by scanning electron microscopy (SEM).

Results: We have now shown inhibitory capacity of IFN-gamma on all three types of unstimulated cells. The growth-inhibitory effect was maximal with SMC, while it was minimal with FB and EC. IFN-gamma abrogated mitogenic responses of SMC but not EC and partially FB to VEGF and FGF stimulation. IFN-alpha was able to inhibit EC growth and, to a lesser extent, FB, and did influence growth rates of SMC. Biochemical analysis of lactate dehydrogenase activity suggested that IFN was not toxic to vascular cells. We also measured the expression of cell adhesive molecules: P- and E-selections, PECAM and ICAM-1. These molecules were upregulated by IFN in EC. Media derived from quiescent human SMC displayed low immunoreactive elastase activity, while conditional media after IFN-gamma treatment but not IFN-alpha treatment had approximately a threefold greater activity.

Conclusion: These data suggest that IFN-gamma significantly inhibits SMC growth in the absence of significant endothelial toxicity and is dose-dependent; however, animal experiments are needed to further explore the antirestenotic effects of IFNs.