Pearce Jeffrey D, Li Jing, Edwards Matthew S, English William P, Geary Randolph L
Division of Surgical Sciences, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
J Vasc Surg. 2004 Jan;39(1):223-8. doi: 10.1016/s0741-5214(03)01037-1.
Constrictive remodeling and new artery wall mass contribute to lumen narrowing in atherosclerosis and following injury. Rho-kinase, an important regulator of myosin phosphorylation and cytoskeletal reorganization, is critical to smooth muscle cell (SMC) growth and vasoconstriction, but its role in artery wall remodeling is poorly defined. We hypothesized that constrictive artery wall remodeling is dependent on Rho signaling so that blocking Rho-kinase would promote outward artery wall remodeling in response to intimal hyperplasia and thus limit lumen narrowing.
To test this hypothesis, we first studied the effects of the Rho-kinase inhibitor fasudil on SMC remodeling of collagen matrix in vitro. Mouse aortic SMCs were seeded into three-dimensional collagen gels with and without fasudil, and extent of contraction was measured at 24 hours. We then used the mouse carotid ligation model to study the effects of Rho-kinase inhibition on remodeling and intimal hyperplasia in vivo. C57B6/J mice were randomly assigned to fasudil (100 mg/kg per day) or vehicle and underwent unilateral carotid artery ligation or sham ligation. Remodeling and wall mass were measured after 28 days.
Fasudil blocked SMC contraction of collagen gels in a dose-dependent manner. Complete inhibition of collagen gel remodeling was achieved between 10 and 30 micromol/L fasudil. In control mice, carotid ligation caused significant thickening of the adventitia, media, and intima (P <.01) and outward remodeling of the carotid wall. The external elastic lamina (EEL) area increased by 14% versus sham (P <.05), but this increase was insufficient to prevent lumen narrowing (-42% vs sham, P <.05). Fasudil treatment had favorable effects on wall mass, inhibiting neointimal (P =.04), medial (P =.03), and adventitial thickening (P =.07) versus controls. Opposite our hypothesis, however, fasudil did not enhance outward artery wall remodeling or improve lumen caliber. Rather, inhibiting Rho-kinase blocked outward remodeling in response to ligation. EEL area was significantly smaller in treated versus control animals (P =.04) and slightly smaller versus shams (P = NS). These data suggest that Rho activation contributes significantly to both hyperplasia and outward remodeling of the injured artery wall. Rho-kinase may prove an important target to limit intimal hyperplasia and prevent restenosis when remodeling is improved by other means (eg, stents).
在动脉粥样硬化及损伤后，缩窄性重塑和新的动脉壁质量增加会导致管腔狭窄。Rho激酶是肌球蛋白磷酸化和细胞骨架重组的重要调节因子，对平滑肌细胞（SMC）生长和血管收缩至关重要，但其在动脉壁重塑中的作用尚不清楚。我们假设缩窄性动脉壁重塑依赖于Rho信号传导，因此阻断Rho激酶将促进动脉壁向外重塑以应对内膜增生，从而限制管腔狭窄。
为验证这一假设，我们首先在体外研究了Rho激酶抑制剂法舒地尔对SMC在胶原基质中重塑的影响。将小鼠主动脉SMC接种到含或不含法舒地尔的三维胶原凝胶中，并在24小时时测量收缩程度。然后我们使用小鼠颈动脉结扎模型在体内研究Rho激酶抑制对重塑和内膜增生的影响。将C57B6/J小鼠随机分为法舒地尔组（每天100mg/kg）或溶剂对照组，进行单侧颈动脉结扎或假结扎。28天后测量重塑和壁质量。
法舒地尔以剂量依赖性方式阻断SMC对胶原凝胶的收缩。在10至30μmol/L法舒地尔之间可实现对胶原凝胶重塑的完全抑制。在对照小鼠中，颈动脉结扎导致外膜、中膜和内膜显著增厚（P<.01）以及颈动脉壁向外重塑。与假手术组相比，外弹性膜（EEL）面积增加了14%（P<.05），但这种增加不足以防止管腔狭窄（-42% vs假手术组，P<.05）。法舒地尔治疗对壁质量有有利影响，与对照组相比，抑制了新生内膜增厚（P=.04）、中膜增厚（P=.03）和外膜增厚（P=.07）。然而，与我们的假设相反，法舒地尔并未增强动脉壁向外重塑或改善管腔内径。相反，抑制Rho激酶阻断了因结扎引起的向外重塑。与对照动物相比，治疗组动物的EEL面积显著更小（P=.04），与假手术组相比略小（P=无显著性差异）。这些数据表明，Rho激活对损伤动脉壁的增生和向外重塑均有显著贡献。当通过其他手段（如支架）改善重塑时，Rho激酶可能被证明是限制内膜增生和预防再狭窄的重要靶点。
