Translational research methods: Renal stem cells

Abstract

The kidney is the main excretory organ in the body and performs essential functions, such as the excretion of waste products from the blood, the regulation of water volume, electrolyte balance and pH levels, and the maintenance of blood pressure, erythropoiesis and bone metabolism. In humans, these functions are carried out by the combined action of approximately two million nephrons, which are the functional units of the kidney. Any pathologic process that leads to a loss of nephrons may eventually cause decreased renal function and perturbs the physiological homeostasis maintained by the kidney, which is a process collectively termed chronic kidney disease (CKD) [1–3]. CKD gradually progress to end stage renal disease (ESRD). At present, ESRD patients have only two therapeutic options: renal transplantation and dialysis therapy. Renal transplantation is a radical treatment, but hampered by serious problems, including the shortage of donor organs and chronic use of immunosuppressive drugs. Dialysis therapy can substitute for a part of renal function, but it eventually causes systemic complications in ESRD patients [3–6]. The prevalence of CKD is increasing worldwide, mainly due to the increased incidence of diabetes mellitus and hypertension. Moreover, CKD is associated with elevated morbidity and mortality due to the increased risk of cardiovascular diseases, which gives growing economic burden to health care systems [7]. Since CKD represents a gradual loss of nephron number, substantial efforts have sought cell sources that can compensate the loss. One option might be the supplementation of renal stem cells [8].