浙江大学沈啸等研究人员合作发现，肾脏巨噬细胞监控并清除尿液中的微粒来防止肾小管阻塞。这一研究成果于2023年12月29日在线发表在国际学术期刊《免疫》上。

研究人员利用高分辨率显微镜发现，肾髓质中的并管巨噬细胞会连续形成跨上皮突起，并对尿液内容物进行“取样”。它们能有效地吸附和吞噬管腔内的沉积物颗粒，并偶尔转移到肾小管腔内，为尿液颗粒的排泄保驾护航。肾脏巨噬细胞数量减少的小鼠容易出现各种肾小管内沉积物，包括肾结石。

从机制上讲，髓质巨噬细胞的跨上皮行为需要整合素β1介导的与肾小管上皮细胞的连接。这些研究结果表明，髓质巨噬细胞会对尿液内容物进行采样，并清除管内颗粒，从而保持肾小管系统畅通无阻。

据了解，当肾小球的滤液流经肾小管系统时，会产生各种微小的沉淀颗粒，包括矿物晶体。清除这些微粒对于确保滤液的自由流动至关重要，而如果不能清除这些微粒，则会导致肾结石的形成和梗阻。然而，清除的基本机制尚不清楚。

附：英文原文

Title: Renal macrophages monitor and remove particles from urine to prevent tubule obstruction

Author: Jian He, Yangyang Cao, Qian Zhu, Xinge Wang, Guo Cheng, Qiang Wang, Rukun He, Haoran Lu, Yuancheng Weng, Genxiang Mao, Yizhong Bao, Jing Wang, Xiaoli Liu, Fei Han, Peng Shi, Xiao Z. Shen

Issue&Volume: 2023-12-29

Abstract: When the filtrate of the glomerulus flows through the renal tubular system, variousmicroscopic sediment particles, including mineral crystals, are generated. Dislodgingthese particles is critical to ensuring the free flow of filtrate, whereas failureto remove them will result in kidney stone formation and obstruction. However, theunderlying mechanism for the clearance is unclear. Here, using high-resolution microscopy,we found that the juxtatubular macrophages in the renal medulla constitutively formedtransepithelial protrusions and “sampled” urine contents. They efficiently sequesteredand phagocytosed intraluminal sediment particles and occasionally transmigrated tothe tubule lumen to escort the excretion of urine particles. Mice with decreased renalmacrophage numbers were prone to developing various intratubular sediments, includingkidney stones. Mechanistically, the transepithelial behaviors of medulla macrophagesrequired integrin β1-mediated ligation to the tubular epithelium. These findings indicatethat medulla macrophages sample urine content and remove intratubular particles tokeep the tubular system unobstructed.

DOI: 10.1016/j.immuni.2023.12.003

Source: https://www.cell.com/immunity/fulltext/S1074-7613(23)00534-4