Role of Immunometabolism in Myocardial Infarction Outcomes in Metabolic Syndrome

肥胖和高血压（即代谢综合征）在经历心肌梗死（MI）的患者中非常普遍。除了增加发生心肌梗死的风险外，这些危险因素还会促进心肌梗死后不良左心室重构，从而增加心肌梗死后心力衰竭的发生。然而，肥胖和高血压相互作用促进心肌梗死后异常结局的机制尚不清楚。一种可能的机制是通过炎症，其中单核细胞/巨噬细胞起关键作用。虽然巨噬细胞对正常伤口愈合和炎症消退至关重要，但在慢性疾病状态下，它们也会促进愈合不足并加剧炎症。心肌梗死后，单核细胞迅速侵入坏死的左室，分化为心肌促炎巨噬细胞，产生炎症反应，随着伤口愈合的进展，分化或“极化”为M2抗炎巨噬细胞，缓解炎症。免疫细胞代谢（免疫代谢）已被确定为决定极化的关键因素；然而，心肌梗死后免疫代谢的作用尚未得到研究。心脏代谢受到慢性压力源（如肥胖和高血压）的损害，这些代谢变化有助于疾病进展。因此，本研究的主要目的是确定肥胖和高血压如何相互作用影响心肌梗死后心脏巨噬细胞极化和代谢，以及操纵巨噬细胞代谢是否可以改善心肌梗死后代谢综合征的结局。为了实现这一目标，小鼠将被喂食慢性高脂肪和高果糖（即西方）饮食来诱导肥胖，并通过腹主动脉缩窄手术诱导高血压。然后通过永久性冠状动脉结扎给予小鼠心肌梗死。巨噬细胞极化和代谢表型将通过荧光活化细胞分选（FACS）、RNA-Seq、糖酵解和氧化代谢来评估。在第2项研究中，小鼠将被给予2-脱氧葡萄糖以扰乱葡萄糖代谢，并被给予亚硝酸钠以增强线粒体脂肪酸氧化。巨噬细胞表型将与心肌梗死后的预后相关，如生存、心功能和心脏重塑。

Obesity and hypertension (i.e. metabolic syndrome) are highly prevalent in patients who experience myocardial infarction (MI). In addition to increasing the risk of developing MI, these risk factors also promote adverse left ventricular remodeling after MI and thus increase the development of heart failure after MI. However, the mechanisms by which obesity and hypertension interact to promote aberrant post-MI outcomes are not well understood. One possible mechanism is through inflammation, in which monocytes/macrophages play key roles. While macrophages are critical for normal wound healing and resolution of inflammation, they can also promote inadequate healing and exacerbate inflammation during chronic disease states. Following MI, monocytes quickly invade the necrotic LV and differentiate into MI pro-inflammatory macrophages to generate an inflammatory response, then as wound healing progresses differentiate or “polarize” into M2 anti-inflammatory macrophages to resolve inflammation. Immune cell metabolism (immunometabolism) has been identified as a key factor dictating polarization; however, the role of immunometabolism following MI has not been investigated. Cardiac metabolism is impaired by chronic stressors on the heart, such as obesity and hypertension, and these changes in metabolism contribute to disease progression. Thus, the main goal of this study is to identify how obesity and hypertension interact to affect cardiac macrophage polarization and metabolism after MI, and whether manipulating macrophage metabolism can improve post-MI outcomes in metabolic syndrome. To accomplish this goal, mice will be fed a chronic high fat and high fructose (i.e. Western) diet to induce obesity, and hypertension will be surgically induced by abdominal aortic coarctation. Mice will then be given MI by permanent coronary artery ligation. Macrophage polarization and metabolic phenotypes will be assessed by fluorescence activated cell sorting (FACS), RNA-Seq, and glycolytic and Oxidative metabolism. In Aim 2, mice will be administered 2-deoxyglucose to perturb glucose metabolism and sodium nitrite to enhance mitochondrial fatty acid oxidation. Macrophage phenotypes will be linked to post-MI outcomes such as survival, cardiac function, and cardiac remodeling.