Abstract: Renal microvascular rarefaction is a key process in the progression of chronic kidney disease (CKD) ,essentially characterized by decreased capillary density, local hypoxia, and insufficient perfusion. With the advancement of technologies such as spatial transcriptomics, multimodal imaging, and intravital imaging, researchers can now re-examine the relationship between microvascular rarefaction and fibrosis from a spatiotemporal perspective. This article focuses on the spatiotemporal dimensions of renal microvascular rarefaction and proposes the concept of a "spatiotemporal causal chain",suggesting that incomplete capillary repair after acute kidney injury (AKI) can evolve into persistent rarefaction. The renal medulla, due to its physiological hypoxia, is more susceptible to ischemia, and the degree of rarefaction is positively correlated with fibrosis. Furthermore, the article constructs an "intervention window" framework, proposing that the optimal timing for intervention is when vascular function declines but fibrosis has not yet become irreversible, which may help delay CKD progression. The authors suggest that in the future, a mapping approach could be used to elucidate the specific differences in the "spatiotemporal causal chain" among different disease types, as well as the duration and molecular markers of the "intervention window". Combined with large sample follow-up studies and the development of detection tools, this strategy may enhance clinical translational value and promote the early identification and precise intervention of CKD.

Key words: Nephrology, Renal fibrosis, Renal microvascular rarefaction, Urinary system, Review

摘要： 肾脏微血管稀疏是慢性肾脏病（CKD）进展的关键环节，其本质特征是毛细血管密度下降、局部缺氧与灌注不足。随着空间转录组学、多模态成像和活体成像等技术的发展，研究者能够从“时空”角度重新审视微血管稀疏与纤维化的关系。本文聚焦肾脏微血管稀疏的时空维度，提出“时空因果链”设想，即急性肾损伤（AKI）后毛细血管修复不完全可演变为持续性稀疏，而肾髓质因生理性低氧更易发生缺血，且稀疏程度与纤维化呈正相关；同时构建了“可干预窗口”框架，认为在血管功能下降、纤维化未固化时为干预时机，可延缓CKD进展。作者认为未来可以通过图谱化方法明确不同肾脏疾病类型中“时空因果链”的特异性差异及“可干预窗口”时长与分子标志物，结合大样本随访数据和检测工具开发，提升临床转化价值，促进CKD早期识别与精准干预。

关键词: 肾脏病学, 肾脏纤维化, 肾脏微血管稀疏, 泌尿系统, 综述