The role of the renin-angiotensin system in pediatric kidney diseases and neonatal development

The local renal renin-angiotensin system (RAS) is regulated independently of the systemic RAS. The renal RAS not only regulates blood pressure and hemodynamics but also plays an important role in the kidney disease development. Many studies have shown that the of angiotensinogen urinary excretion rate is a specific index of the intrarenal RAS activation. Moreover, urinary angiotensinogen (AGT) levels reflect the intrarenal RAS status associated with hypertension, chronic kidney disease, and diabetic nephropathy. In addition, urinary AGT is a novel biomarker of intrarenal RAS activation during neonatal kidney development. Furthermore, angiotensin-converting enzyme 2 and the (pro)renin receptor have recently been identified as new components of the RAS that have novel functions in kidney diseases and development. This review summarizes the current knowledge on intrarenal RAS activation in the context of pathological and physiological processes in children. J. Med. Invest. 72 : 241-244, August, 2025.