Institute of Cellular Therapeutics, Allegheny Health Network, 11th Floor South Tower, 320 East North Avenue, Pittsburgh, PA, S15212, USA.
Department of Molecular Physiology and Biophysics, Vanderbilt University., Nashville, TN, 37232, USA.
Cardiovasc Diabetol. 2022 Jul 12;21(1):130. doi: 10.1186/s12933-022-01564-y.
Liver pathology (LP) characteristic of non-alcoholic fatty acid disease (NAFLD)/non-alcoholic steatohepatitis (NASH) is a prevalent co-morbidity of type 2 diabetes (T2D). Accumulating evidence indicates that neutrophils driving insulin resistance (IR), including hepatic IR, precipitate T2D-associated NAFLD/NASH. We hypothesized that targeting neutrophil accumulation into insulin-sensitive tissues in mice using a CXCR2 antagonist under T2D-precipitating high fat diet (HFD) could improve insulin sensitivity and prevent the progression towards liver pathology reminiscent of NAFLD/NASH.
Mice were age-matched and on standard rodent chow prior to 1:1 randomization into control and HFD formulated with the CXCR2 antagonist AZD5069 or with biologically inactive substitute. They were monitored for metabolic changes including insulin sensitivity using the hyperinsulinemic-euglycemic clamp and hepatic histopathologic evaluation in H&E-stained sections as well as via immunofluorescence microscopy of liver sections for leukocyte markers, collagen 1A1 formation, α-smooth muscle actin (SMA), and galectin-3 expression, for 16 weeks. Statistical tests used to determine significant differences among study groups and outcomes include Student's t-test, one-way ANOVA, repeated measures two-way ANOVA, and Fisher's exact test, depending on the analytical question.
Compared to mice on HFD, mice in the AZD5069-formulated HFD exhibited improved insulin sensitivity, a modest reduction in weight gain, and a significant improvement in LP and markers related to NAFLD/NASH. Mice in the AZD5069-formulated HFD also exhibited reduced neutrophil accumulation into the liver at the end of the 16 week study period.
These results show, for the first time, the effectiveness of a selective CXCR2 antagonist to improve insulin sensitivity, concomitantly preventing the progression towards LP characteristic of NAFLD/NASH. This represents a novel approach to target IR and developing LP under T2D-susceptible conditions using a single agent. Furthermore, our data extend the growing evidence in support of neutrophils as a leukocyte population that imprints and maintains a chronic inflammatory state in the progression of dysregulated metabolism in liver-specific co-morbid conditions.
非酒精性脂肪性肝病（NAFLD）/非酒精性脂肪性肝炎（NASH）的肝脏病理学（LP）特征是 2 型糖尿病（T2D）的常见合并症。越来越多的证据表明，导致胰岛素抵抗（IR）的中性粒细胞，包括肝 IR，会引发与 T2D 相关的 NAFLD/NASH。我们假设，在 T2D 诱发的高脂肪饮食（HFD）下，使用 CXCR2 拮抗剂将中性粒细胞募集到胰岛素敏感组织中，可以改善胰岛素敏感性并防止向类似于 NAFLD/NASH 的肝病理学进展。
在将年龄匹配的小鼠进行 1:1 随机分组为对照组和 HFD 组之前，所有小鼠均接受标准啮齿动物饲料喂养，HFD 组中添加了 CXCR2 拮抗剂 AZD5069 或具有生物活性的替代物。通过高胰岛素-正葡萄糖钳夹监测代谢变化，包括胰岛素敏感性，并通过 H&E 染色切片进行肝组织病理学评估，以及通过免疫荧光显微镜检查肝切片中的白细胞标志物、胶原 1A1 形成、α-平滑肌肌动蛋白（SMA）和半乳糖凝集素-3 表达，共进行 16 周。用于确定研究组和结果之间显著差异的统计检验包括学生 t 检验、单因素方差分析、重复测量双向方差分析和 Fisher 精确检验，具体取决于分析问题。
与 HFD 组的小鼠相比，AZD5069 配方 HFD 组的小鼠胰岛素敏感性得到改善，体重增加适度减少，LP 和与 NAFLD/NASH 相关的标志物显著改善。在 16 周研究结束时，AZD5069 配方 HFD 组的小鼠肝脏中的中性粒细胞积聚也减少。
这些结果首次表明，选择性 CXCR2 拮抗剂可有效改善胰岛素敏感性，同时防止 LP 向 NAFLD/NASH 特征发展。这代表了一种在 T2D 易感条件下使用单一药物靶向 IR 和发展 LP 的新方法。此外，我们的数据扩展了越来越多的证据，支持中性粒细胞作为一种白细胞群体，在肝脏特异性合并症中代谢失调的进展过程中，会产生并维持慢性炎症状态。
