Division of Cardiothoracic Surgery, Cardiovascular Research Center, Warren Alpert Medical School of Brown University, Providence, RI, 02905, USA.
Basic Res Cardiol. 2012 Mar;107(2):243. doi: 10.1007/s00395-012-0243-y. Epub 2012 Jan 10.
Ossabaw miniswine have been naturally selected to efficiently store large amounts of lipids offering them a survival advantage. Our goal was to evaluate the myocardial response to chronic ischemia of the Ossabaw consuming a hypercaloric, high-fat/cholesterol diet with and without metformin supplementation. At 6 weeks of age animals were fed either a regular diet (OC, n = 9), a hypercaloric high-fat/cholesterol diet (OHC, n = 9), or a hypercaloric high-fat/cholesterol diet supplemented with metformin (OHCM, n = 8). At 9 weeks, all animals underwent ameroid constrictor placement to the left circumflex coronary artery to simulate chronic ischemia. Seven weeks after ameroid placement, all animals underwent hemodynamic and functional measurements followed by cardiac harvest. Both OHC and OHCM animals developed significantly greater weight gain, total cholesterol, and LDL:HDL ratio compared to OC controls. Metformin administration reversed diet-induced hypertension and glucose intolerance. There were no differences in global and regional contractility, myocardial perfusion, capillary and arteriolar density, or total protein oxidation between groups. Myocardial protein expression of VEGF, PPAR-α, γ, and δ was significantly increased in the OHC and OHCM groups. Microvessel reactivity was improved in the OHC and OHCM groups compared to controls, and correlated with increased p-eNOS expression. Overfed Ossabaw miniswine develop several components of metabolic syndrome. However, impairments of myocardial function, neovascularization and perfusion were not present, and microvessel reactivity was paradoxically improved in hypercholesterolemic animals. The observed cardioprotection despite metabolic derangements may be due to lipid-dependant upregulation of the PPAR pathway which is anti-inflammatory and governs myocardial fatty acid metabolism.
奥萨索普小型猪已经过自然选择,能够有效地储存大量脂肪,从而为它们提供生存优势。我们的目标是评估奥萨索普小型猪在食用高热量高脂肪/高胆固醇饮食并补充二甲双胍时对慢性缺血的心肌反应。在 6 周龄时,动物分别喂食普通饮食(OC,n=9)、高热量高脂肪/高胆固醇饮食(OHC,n=9)或高热量高脂肪/高胆固醇饮食补充二甲双胍(OHCM,n=8)。在 9 周龄时,所有动物均接受环甲缩窄器放置到左旋冠状动脉以模拟慢性缺血。在环甲缩窄器放置 7 周后,所有动物均进行血流动力学和功能测量,然后进行心脏收获。与 OC 对照组相比,OHC 和 OHCM 动物的体重增加、总胆固醇和 LDL:HDL 比值显著增加。二甲双胍的给药逆转了饮食引起的高血压和葡萄糖不耐受。各组间整体和局部收缩性、心肌灌注、毛细血管和小动脉密度或总蛋白氧化无差异。OHC 和 OHCM 组的 VEGF、PPAR-α、γ 和 δ 的心肌蛋白表达显著增加。与对照组相比,OHC 和 OHCM 组的微血管反应性得到改善,并且与增加的 p-eNOS 表达相关。过度喂养的奥萨索普小型猪会出现几种代谢综合征的成分。然而,心肌功能、新生血管和灌注的损伤并不存在,并且高脂血症动物的微血管反应性反而得到改善。尽管存在代谢紊乱,但观察到的心脏保护可能是由于脂质依赖性上调 PPAR 途径,该途径具有抗炎作用,并控制心肌脂肪酸代谢。