肾小管上皮细胞程序性坏死对慢性肾脏病患者肾损伤的影响

目的:分析不同分期慢性肾脏病（chronic kidney disease，CKD）患者肾组织中发生程序性坏死的肾小管上皮细胞数量及其与临床病理指标的相关性，探讨肾小管上皮细胞程序性坏死在CKD患者肾小管上皮细胞过度死亡、慢性肾损伤进展中的作用。方法:收集2017年6月至2019年6月于海南医学院第一附属医院行肾活检且...

Effects of renal tubular epithelial cell necroptosis on kidney injury in patients with chronic kidney disease

Objective To investigate the number of necroptotic renal tubular epithelial cells in renal tissues of patients with chronic kidney disease (CKD) and the correlation with clinicopathologic parameters, and explore its role in the progression of the excessive loss of renal tubular cells and chronic kidney injury. Methods Renal tissue samples from 60 patients (18-65 years old) with CKD proven by kidney biopsy in the First Affiliated Hospital of Hainan Medical University from June 2017 to June 2019 were collected. According to internationally accepted K/DOQI guidelines, the patients were divided into 1-4 stages of CKD, with 15 cases in each stage. The number of necroptotic renal tubular epithelial cells in patients with different stages of CKD was detected using receptor-interacting protein 3 (RIP3) and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) fluorescent staining, and the expression of RIP3 and MLKL, marker protein of necroptosis, was detected by immunohistochemistry. Pearson correlation analysis was used to analyze the correlation between the percentage of necroptotic renal tubular epithelial cells and clinicopathologic parameters. In addition, the expression of angiotensinogenⅡ receptor (AT2R) in renal tissue and its correlation with the percentage of necroptotic renal tubular epithelial cells were analyzed. Results With the development of CKD, the structural destruction of renal tubules in patients with CKD was gradually aggravated, and the renal tubules in the corresponding areas were atrophied, accompanied by worsening interstitial fibrosis. The adjacent renal tubules were focally dilated and numerous protein tubules were seen in the tubules. Importantly, renal tubular injury score in second and third stage of CKD was significantly higher than that in control group (both P＜0.01). TUNEL+RIP3 immunofluorescence staining results showed that the percentage of TUNEL/RIP3 double positive renal tubular epithelial cells (necroptotic renal tubular epithelial cells) in renal tubules of the second and third stage of CKD was higher (all P＜0.01). Immunohistochemical results showed that RIP3, MLKL and AT2R proteins were mainly expressed in cytoplasm of renal tubular epithelial cells, and the expression of RIP3, MLKL and AT2R in renal tubular epithelial cells was higher in the second and third stage of CKD patients (all P＜0.05). Pearson correlation analysis showed that the percentage of necroptotic renal tubular epithelial cells was positively correlated with blood urea nitrogen (r=0.514, P=0.003), serum creatinine (r=0.507, P=0.019), serum cystatin C (r=0.571, P=0.026), serum uric acid (r=0.592, P=0.008), renal tubules injury score (r=0.901, P＜0.001), renal interstitial fibrosis index (r=0.700, P=0.001) and the expression of AT2R protein in renal tissue (r=0.715，P=0.001). Conclusions As CKD progresses, necroptosis of renal tubular epithelial cells in CKD patients occurs. The necroptotic cell death may be an important factor leading to renal tubular epithelial cell excessive death and the progression of chronic kidney injury. Furthermore, necroptosis of renal tubular epithelial cells may be related to the high expression of AT2R in kidney tissue.