Kanzaki Go
Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-Ku, Tokyo, 105-8461, Japan.
Clin Exp Nephrol. 2025 Apr 19. doi: 10.1007/s10157-025-02662-3.
The number of nephrons is a key determinant of blood pressure regulation and chronic kidney disease (CKD) progression. Although traditional estimates suggest approximately one million nephrons per kidney, modern stereological approaches reveal substantial variability, that is influenced by ethnicity, birth weight, and other early life factors. This review evaluates the century-long evolution of nephron number research, variations across racial and ethnic groups, and explores how factors, such as body size, aging, and lifestyle risks, influence nephron endowment. Techniques for nephron quantification, from design-based stereology to emerging in vivo imaging, are also discussed. Recent research suggests markedly lower nephron counts in Japanese populations, especially among individuals with hypertension or CKD. The autopsy-based investigation in the present study included 27 middle-aged to older Japanese men (9 normotensive, 9 hypertensive, and 9 participants with CKD) who underwent dissector-fractionator stereology to quantify non-sclerosed glomeruli. Normotensive men had an average of approximately 640,399 non-sclerosed glomeruli. In contrast, the hypertensive participants had approximately 392,108 non-sclerosed glomeruli and those with CKD had only 268, 043. These findings underscore the potential influence of limited nephron reserves on hypertension and CKD in Japan. Current evidence suggests that nephron number estimates can guide therapeutic decisions and predict CKD outcomes, while advancements in real-time imaging offer potential avenues for non-invasive nephron assessment. Collectively, these developments highlight the central importance of nephron quantity in nephrology and enable targeted interventions aimed at preserving kidney function and mitigating the CKD burden.
肾单位数量是血压调节和慢性肾脏病（CKD）进展的关键决定因素。尽管传统估计表明每个肾脏约有100万个肾单位，但现代体视学方法显示存在很大差异，这种差异受种族、出生体重和其他早期生活因素影响。本综述评估了肾单位数量研究长达一个世纪的演变、不同种族和民族之间的差异，并探讨了诸如体型、衰老和生活方式风险等因素如何影响肾单位禀赋。还讨论了从基于设计的体视学到新兴的体内成像等肾单位量化技术。最近的研究表明，日本人群中的肾单位计数明显较低，尤其是在患有高血压或CKD的个体中。本研究基于尸检的调查纳入了27名中年至老年日本男性（9名血压正常者、9名高血压患者和9名CKD患者），他们接受了剖分分离体视学以量化未硬化的肾小球。血压正常的男性平均约有640,399个未硬化的肾小球。相比之下，高血压参与者有大约392,108个未硬化的肾小球，而CKD患者只有268,043个。这些发现强调了有限的肾单位储备对日本高血压和CKD的潜在影响。目前的证据表明，肾单位数量估计可以指导治疗决策并预测CKD结局，而实时成像的进展为非侵入性肾单位评估提供了潜在途径。总的来说，这些进展凸显了肾单位数量在肾脏病学中的核心重要性，并使旨在保护肾功能和减轻CKD负担的针对性干预成为可能。
