The effect of cilostazol on the platelet-derived growth factor-beta/beta isoform reduction on venous hyperplasia in an experimental balloon-induced injury model.

Abstract

Intimal hyperplasia is the response to endothelial injury. Platelet-derived growth factor is released early and favors the formation of intimal hyperplasia. Although multiple treatments, from open surgery to endovascular techniques, have been used they remain controversial. There is currently interest in developing pharmacological strategies to address this pathology. Local vascular inflammation induced by vessel barotrauma generates intimal hyperplasia due to mechanical stress over the venous endothelium. Cilostazol is a selective phosphodiesterase type 3 (PDE3) selective inhibitor with a regulatory effect over intimal hyperplasia. The objective was to investigate cilostazol's role in inhibiting smooth muscle cell proliferation due to changes in the expression and release of PDGF-BB isoform and the effect on developing IH using an experimental model of vascular barotrauma (balloon-induced injury model). We included 12 New Zealand rabbits. The balloon-induced injury model (BIIM) and experimental group cilostazol (20mg/kg/day) included 6 rabbits each. Contralateral veins from 6 rabbits used in BIIM model has been taken as control group. We measured and compared the expression of PDGF-BB and the development of IH. A pathologist board chooses a PDGFRα antibody to localized its expression by immunohistochemistry analysis. Subsequently, using an automated immunohistochemical staining machine, the PDGFR expression was evaluated using a Zeiss Primo Star 4 light microscope. The measurement obtained in the intimal layer was: 126.12μm2 in the CG, 232μm2 in the BIIM group, and 178μm2 in the EG. A statistically significant difference was observed. Baseline serum concentrations of PDGF-BB in the BIIM group were 0.22pg/mL. At 12h 0.42pg/mL, and 0.17pg/mL at seven days. In the experimental group, the basal levels were 0.33pg/mL. With the use of cilostazol, a lower peak was obtained at 12h (0.08pg/mL). This difference was statistically significant. Cilostazol induced a significant reduction of IH caused by barotrauma in the venous endothelium, which correlates with decrease in the PDGF-BB in serum. This could be attributed to the pharmacologic effect on PDGFR expression.