肥胖代谢紊乱加剧了猪中度冠状动脉狭窄远端的心肌细胞丢失,但不影响整体心脏功能。

Obesity-metabolic derangement exacerbates cardiomyocyte loss distal to moderate coronary artery stenosis in pigs without affecting global cardiac function.

机构信息

Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota;

出版信息

Am J Physiol Heart Circ Physiol. 2014 Apr 1;306(7):H1087-101. doi: 10.1152/ajpheart.00052.2013. Epub 2014 Feb 7.

Abstract

Obesity associated with metabolic derangements (ObM) worsens the prognosis of patients with coronary artery stenosis (CAS), but the underlying cardiac pathophysiologic mechanisms remain elusive. We tested the hypothesis that ObM exacerbates cardiomyocyte loss distal to moderate CAS. Obesity-prone pigs were randomized to four groups (n = 6 each): lean-sham, ObM-sham, lean-CAS, and ObM-CAS. Lean and ObM pigs were maintained on a 12-wk standard or atherogenic diet, respectively, and left circumflex CAS was then induced by placing local-irritant coils. Cardiac structure, function, and myocardial oxygenation were assessed 4 wk later by computed-tomography and blood oxygenation level dependent (BOLD) MRI, the microcirculation with micro-computed-tomography, and injury mechanisms by immunoblotting and histology. ObM pigs showed obesity, dyslipidemia, and insulin resistance. The degree of CAS (range, 50-70%) was similar in lean and ObM pigs, and resting myocardial perfusion and global cardiac function remained unchanged. Increased angiogenesis distal to the moderate CAS observed in lean was attenuated in ObM pigs, which also showed microvascular dysfunction and increased inflammation (M1-macrophages, TNF-α expression), oxidative stress (gp91), hypoxia (BOLD-MRI), and fibrosis (Sirius-red and trichrome). Furthermore, lean-CAS showed increased myocardial autophagy, which was blunted in ObM pigs (downregulated expression of unc-51-like kinase-1 and autophagy-related gene-12; P < 0.05 vs. lean CAS) and associated with marked apoptosis. The interaction diet xstenosis synergistically inhibited angiogenic, autophagic, and fibrogenic activities. ObM exacerbates structural and functional myocardial injury distal to moderate CAS with preserved myocardial perfusion, possibly due to impaired cardiomyocyte turnover.

摘要

肥胖与代谢紊乱(ObM)相关,使冠状动脉狭窄(CAS)患者的预后恶化,但潜在的心脏病理生理机制仍不清楚。我们测试了以下假说:ObM 会加重中度 CAS 远端的心肌细胞损失。易肥胖的猪被随机分为四组(每组 6 只):瘦对照、ObM 对照、瘦 CAS 和 ObM-CAS。瘦猪和 ObM 猪分别接受 12 周的标准或致动脉粥样硬化饮食,然后通过放置局部刺激线圈诱导左回旋支 CAS。4 周后,通过计算机断层扫描和血氧水平依赖(BOLD)MRI、微血管计算机断层扫描评估心脏结构、功能和心肌氧合,通过免疫印迹和组织学评估损伤机制。ObM 猪表现出肥胖、血脂异常和胰岛素抵抗。瘦猪和 ObM 猪的 CAS 程度(范围 50-70%)相似,静息心肌灌注和整体心脏功能保持不变。在瘦猪中观察到的中度 CAS 远端的血管生成增加在 ObM 猪中减弱,并且也显示出微血管功能障碍和炎症增加(M1-巨噬细胞,TNF-α 表达)、氧化应激(gp91)、缺氧(BOLD-MRI)和纤维化(天狼星红和三原色)。此外,瘦-CAS 显示心肌自噬增加,而 ObM 猪的自噬减少(自噬相关基因 12 和自噬相关基因 12 的表达下调;与瘦 CAS 相比,P < 0.05),并且与明显的凋亡相关。饮食 x 狭窄的相互作用协同抑制了血管生成、自噬和纤维生成活性。ObM 加重了中度 CAS 远端的结构性和功能性心肌损伤,尽管心肌灌注保持不变,但可能是由于心肌细胞更新受损所致。

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