基于GLP-1抑制血管外周脂肪组织细胞焦亡探讨胃旁路术拮抗肥胖2型糖尿病血管外膜重构

Adventitia remodeling is an early stage of atherosclerosis in type 2 diabetes mellitus (AS). Perivascular adipose tissue (PVAT) inflammation plays an important role in adventitia remodeling. Pyroptosis induced by obesity. Gastric bypass improves atherosclerosis in type 2 diabetes mellitus. GLP-1 increased after gastric bypass. According to previous studies, we hypothesized that GLP-1 increased after gastric bypass, GLP-1 inhibited the pyroptosis in peripheral vascular adipose tissue (PVAT), then inhibited adventitia remodeling. We established a model of gastric bypass in obese type 2 diabetic rats, primary cultured PVAT adipocytes-detect pyroptosis, and aortic sinus adventitia fibroblasts (AF)- detect proliferation and differentiation, in order to clarify the inhibition of adventitia remodeling by gastric bypass, and prove key roles of GLP-1 in gastric bypass inhibiting adventitia remodeling. PVAT adipocytes and AF were co-cultured. Lipopolysaccharide stimulates PVAT adipocytes to establish a pyroptosis model. GLP-1 was used to treat cells to verify that GLP-1 inhibited the pyroptosis of PVAT adipocytes and the differentiation and proliferation of AF; GSDMD of PVAT adipocytes was silenced to verify that pyroptosis promoted the differentiation and proliferation of AF; GSDMD of PVAT adipocytes was overexpressed to demonstrated the role of pyroptosis in the inhibition of GLP-1 to the differentiation and proliferation of AF. This study provides a new perspective for the mechanism of gastric bypass interventing AS in obesity with type 2 diabetes.

血管外膜重构是2型糖尿病动脉粥样硬化病变（AS）早期环节，血管外周脂肪组织(PVAT)炎症在血管外膜重构中起重要作用，肥胖可诱导脂肪细胞焦亡，胃旁路术改善肥胖2型糖尿病AS，且术后GLP-1升高。根据前期研究和文献，我们提出：胃旁路术后GLP-1水平增加，GLP-1抑制PVAT细胞焦亡，拮抗血管外膜重构。本项目1.建立肥胖2型糖尿病大鼠胃旁路术模型，原代培养PVAT脂肪细胞后检测焦亡及主动脉窦血管外膜成纤维细胞(AF)增殖分化，明确胃旁路术抑制血管外膜重构及PVAT焦亡，并验证GLP-1在上述效应中的关键作用；2.将PVAT脂肪细胞(脂多糖刺激建立焦亡模型)和AF共培养，明确GLP-1抑制PVAT脂肪细胞焦亡、AF增殖分化；沉默与过表达PVAT脂肪细胞GSDMD，阐明焦亡促进AF增殖分化及其在GLP-1拮抗AF增殖分化中的作用。本研究为胃旁路术改善肥胖2型糖尿病AS的机制研究提供新视角。

血管病变是2型糖尿病常见并发症，减重代谢手术可干预糖尿病和血管病变的发生发展，但机制不明确，胰高血糖素样肽–1 (GLP-1）在减重术后明显升高，是手术改善肥胖糖尿病血糖异常和血管炎症的重要原因。本项目通过real-time PCR、Western blot等发现较之SD大鼠，肥胖糖尿病大鼠胰腺组织ABCA1表达降低，油红“O”染色显示胰腺组织出现明显脂质沉积，组织胆固醇含量测定发现胰腺组织胆固醇含量增加，HE染色显示胰岛体积显著缩小，结构紊乱。艾塞那肽可上调肥胖糖尿病大鼠胰腺组织ABCA1表达，减轻胰腺组织脂质沉积，降低胰腺组织胆固醇含量，胰岛数目、体积增多，排列更为规则。在 ZDF 大鼠血管周围脂肪组织( PVAT)中表达最丰富的炎性体是 NLRP3小体。与对照相比，PVAT中的NLRP3、caspase-1、IL-1b、IL-18 和 GSDMD 明显上调组织，GLP-1 逆转这种变化。加入NF-κB激活剂后GLP-1抑制 NLRP3 炎症小体介导的炎症反应。本项目发现GLP-1抑制NLRP3炎症体介导的血管周围脂肪组织炎症，并通过抑制NF-κB通路拮抗NLRP3炎症体介导的PVAT炎症. 糖脂毒性可导致大鼠胰腺组织ABCA1表达降低，胆固醇流出受阻，胰腺组织胆固醇蓄积。GLP-1可上调肥胖糖尿病大鼠胰腺组织ABCA1介导的胆固醇流出，明显降低胆固醇含量，改善胰岛功能。