Effect of endothelial and adventitial injury on somatostatin receptor expression

Background. The somatostatin analog, angiopeptin, inhibits intimal hyperpla sia formation; although the specific somatostatin receptor (SSTR) subtypes transducing this effect are unknown. The purpose of this study was to deter mine the expression of SSTR subtypes in rat iliac arteries after balloon ca theter endothelial injury and perivascular dissection. Methods, Male rats received balloon endothelial injury to their lep common and external iliac arteries with or without circumferential arterial dissec tion. The right arteries served as controls. At I and 2 months after intima l injury, animals were killed and their iliac arteries harvested and studie d for SSTR expression by using immunocytochemical and molecular techniques. Quantitative polymerase chain reaction was used to determine the level of SSTR expression, Results, Normal rat iliac arteries expressed only SSTR2 and 3. After balloo n endothelial injury, there was significant upregulation of SSTR2 messenger RNA at 1 and 2 months after injury as compared with controls (I month, 1.8 +/- 0.3 vs 0.4 +/- 0.1 zmol, P < .001; 2 months, 2.7 +/- 0.5 vs 1.1 +/- 0. 2 zmol, P < .05). The addition of adventitial dissection to endothelial inj ury also showed a significant increase in SSTR2 expression (I month, 2.4 +/ - 0.4 vs 0.8 +/- 0.2, P < .05; 2 months, 1.3 +/- 0.3 vs 0.7 +/- 0.3, P < .0 5), but not significantly greater than that seen after balloon endothelial injury alone. Conclusions. These findings show that SSTR2 is the primary SSTR that is upr egulated after injury and likely mediates the effects of somatostatin analo gs on intimal hyperplasia.