Madigan Michael, Entabi Fateh, Zuckerbraun Brian, Loughran Patricia, Tzeng Edith
Department of Veterans Affairs Medical Center, University of Pittsburgh, Pittsburgh, Pa; Division of Vascular Surgery, University of Pittsburgh, Pittsburgh, Pa.
Department of Veterans Affairs Medical Center, University of Pittsburgh, Pittsburgh, Pa; Department of Surgery, University of Pittsburgh, Pittsburgh, Pa.
J Vasc Surg. 2015 Apr;61(4):1026-33. doi: 10.1016/j.jvs.2013.11.072. Epub 2014 Jan 11.
Intimal hyperplasia (IH) contributes to the failure of vascular interventions. While many investigational therapies inhibit the development of IH in animal models, few of these potential therapies can reverse established lesions. Inhaled carbon monoxide (CO) dramatically inhibits IH in both rats and pigs when given perioperatively. It also prevented the development of pulmonary arterial hypertension in rodents. Interestingly, CO could reverse pulmonary artery structural changes and right heart hemodynamic changes when administered after the establishment of pulmonary hypertension. Thus, we hypothesize that inhaled CO may mediate the regression of established neointimal lesions.
Rats underwent carotid artery balloon angioplasty injury. Carotid arteries were collected at 2 and 4 weeks after injury for morphometric analysis of the neointima. Another group was treated with inhaled CO (250 parts per million) for 1 hour daily from week 2 until week 4. Additional rats were sacrificed 3 days after initiating CO treatment, and the carotid arteries were examined for apoptosis by terminal deoxynucleotidyl transferase dUTP nick end-labeling, proliferation by Ki67 staining, and autophagy by microtubule-associated protein light chain 3 I/II staining.
At 2 weeks following injury, sizable neointimal lesions had developed (intimal/media = 0.92 ± 0.22). By 4 weeks, lesion size remained stable (0.80 ± 0.09). Delayed inhaled CO treatment greatly reduced neointimal lesion size vs the 2- and 4-week control mice (0.38 ± 0.05; P < .05). Arteries from the CO-treated rats exhibited significantly reduced apoptosis compared with control vessels (3.18% ± 1.94% vs 16.26% ± 5.91%; P = .036). Proliferation was also dramatically reduced in the CO-treated animals (2.98 ± 1.55 vs 10.37 ± 2.80; P = .036). No difference in autophagy between control and CO-treated rats was detected.
Delayed administration of inhaled CO reduced established neointimal lesion size. This effect was mediated by the antiproliferative effect of CO on medial and intimal smooth muscle cells without increases in arterial wall apoptosis or autophagy. Future studies will examine additional time points to determine if there is temporal variation in the rates of apoptosis and autophagy.
内膜增生（IH）是血管介入治疗失败的原因之一。虽然许多研究性疗法在动物模型中可抑制IH的发展，但这些潜在疗法中很少能逆转已形成的病变。围手术期给予吸入一氧化碳（CO）可显著抑制大鼠和猪的IH。它还能预防啮齿动物肺动脉高压的发展。有趣的是，在肺动脉高压形成后给予CO，可逆转肺动脉结构变化和右心血流动力学变化。因此，我们推测吸入CO可能介导已形成的新生内膜病变的消退。
对大鼠进行颈动脉球囊血管成形术损伤。在损伤后2周和4周收集颈动脉，用于新生内膜的形态计量分析。另一组从第2周开始至第4周每天吸入CO（百万分之250）1小时。在开始CO治疗3天后处死另外的大鼠，通过末端脱氧核苷酸转移酶dUTP缺口末端标记法检测颈动脉的凋亡情况，通过Ki67染色检测增殖情况，通过微管相关蛋白轻链3 I/II染色检测自噬情况。
损伤后2周，出现了相当大的新生内膜病变（内膜/中膜=0.92±0.22）。到4周时，病变大小保持稳定（0.80±0.09）。与2周和4周的对照小鼠相比，延迟吸入CO治疗大大减小了新生内膜病变的大小（0.38±0.05；P<.05）。与对照血管相比，CO处理大鼠的动脉凋亡明显减少（3.18%±1.94%对16.26%±5.91%；P=.036）。CO处理动物的增殖也显著降低（2.98±1.55对10.37±2.80；P=.036）。未检测到对照大鼠和CO处理大鼠在自噬方面的差异。
延迟给予吸入CO可减小已形成的新生内膜病变的大小。这种作用是由CO对中膜和内膜平滑肌细胞的抗增殖作用介导的，而动脉壁凋亡或自噬并未增加。未来的研究将检查更多时间点，以确定凋亡和自噬速率是否存在时间变化。
