Pallero MA, Talbert Roden M, Chen YF, Anderson PG, Lemons J, Brott BC, Murphy-Ullrich JE. Stainless steel ions stimulate increased thrombospondin-1-dependent TGF-beta activation by vascular smooth muscle cells: implications for in-stent restenosis.
J Vasc Res 2009;
47:309-22. [PMID:
20016205 DOI:
10.1159/000265565]
[Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Accepted: 06/02/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS
Despite advances in stent design, in-stent restenosis (ISR) remains a significant clinical problem. All implant metals exhibit corrosion, which results in release of metal ions. Stainless steel (SS), a metal alloy widely used in stents, releases ions to the vessel wall and induces reactive oxygen species, inflammation and fibroproliferative responses. The molecular mechanisms are unknown. TGF-beta is known to be involved in the fibroproliferative responses of vascular smooth muscle cells (VSMCs) in restenosis, and TGF-beta antagonists attenuate ISR. We hypothesized that SS ions induce the latent TGF-beta activator, thrombospondin-1 (TSP1), through altered oxidative signaling to stimulate increased TGF-beta activation and VSMC phenotype change.
METHODS
VSMCs were treated with SS metal ion cocktails, and morphology, TSP1, extracellular matrix production, desmin and TGF-beta activity were assessed by immunoblotting.
RESULTS
SS ions stimulate the synthetic phenotype, increased TGF-beta activity, TSP1, increased extracellular matrix and downregulation of desmin in VSMCs. Furthermore, SS ions increase hydrogen peroxide and decrease cGMP-dependent protein kinase (PKG) signaling, a known repressor of TSP1 transcription. Catalase blocks SS ion attenuation of PKG signaling and increased TSP1 expression.
CONCLUSIONS
These data suggest that ions from stent alloy corrosion contribute to ISR through stimulation of TSP1-dependent TGF-beta activation.
Collapse