Klotho was originally identified in a mutant mouse strain unable to express the gene that consequently showed shortened life spans. In humans, low serum Klotho levels are related to the prevalence of cardiovascular diseases in community-dwelling adults. However, it is unclear whether the serum Klotho levels are associated with signs of vascular dysfunction such as arterial stiffness, a major determinant of prognosis, in human subjects with chronic kidney disease (CKD). We determined the levels of serum soluble Klotho in 114 patients with CKD using ELISA and investigated the relationship between the level of Klotho and markers of CKD-mineral and bone disorder (CKD-MBD) and various types of vascular dysfunction, including flow-mediated dilatation, a marker of endothelial dysfunction, ankle-brachial pulse wave velocity (baPWV), a marker of arterial stiffness, intima-media thickness (IMT), a marker of atherosclerosis, and the aortic calcification index (ACI), a marker of vascular calcification. The serum Klotho level significantly correlated with the 1,25-dihydroxyvitamin D level and inversely correlated with the parathyroid hormone level and the fractional excretion of phosphate. There were significant decreases in serum Klotho in patients with arterial stiffness defined as baPWV≥1400 cm/sec, atherosclerosis defined as maximum IMT≥1.1 mm and vascular calcification scores of ACI>0%. The serum Klotho level was a significant determinant of arterial stiffness, but not endothelial dysfunction, atherosclerosis or vascular calcification, in the multivariate analysis in either metabolic model, the CKD model or the CKD-MBD model. The adjusted odds ratio of serum Klotho for the baPWV was 0.60 (p = 0.0075). Decreases in the serum soluble Klotho levels are independently associated with signs of vascular dysfunction such as arterial stiffness in patients with CKD. Further research exploring whether therapeutic approaches to maintain or elevate the Klotho level could improve arterial stiffness in CKD patients is warranted.

Kidney is thought to be a regenerative organ in terms of repair from acute tubular injury. It is unknown whether cell population contributes to repair disordered kidney. We attempted to identify and isolate highly proliferative cells from a single cell. We dissected a single nephron from adult rat kidney. Isolated nephrons were separated into segments and cultured. Outgrowing cells were replated after limiting dilution so that each well contained a single cell. One of cell line which was the most potent to grow was designated as rKS56. rKS56 cells showed cobblestone appearance and expressed immature cell markers relating to kidney development and mature tubular cell markers. rKS56 cells grew exponentially and could be maintained for 300 days without transformation. In different culture conditions, rKS56 cells differentiated into mature tubular cells defined by aquaporin‐1, 2 expression, and responsiveness to parathyroid hormone or vasopressin. Engrafted to kidney in rat ischemic reperfusion model, rKS56 cells replaced in injured tubules in part after implantation and improved renal function. These results suggest rKS56 cells possess character such as self‐renewal, multi‐plasticity and capability of tissue repair. rKS56 may possibly contribute to the future development of cell therapy for renal regeneration. Kitamura, S., Yamasaki, Y., Kinomura, M., Sugaya, T., Sugiyama, H., Maeshima, Y., Makino, H. Establishment and characterization of renal progenitor like cells from S3 segment of nephron in rat adult kidney. FASEB J. 19, 1789–1797 (2005)

In recent years, a concept of renal rehabilitation has become widely known among nephrology specialists, dialysis specialists, kidney transplantation specialists, rehabilitation specialists, nutrition specialists, guideline specialists, nurses, physiotherapists, and representatives of patients. Therefore, in order to make it clear the definition, methods, and effectiveness of renal rehabilitation in Japan, we launched Renal Rehabilitation Guideline Preparation Committee in 2016 as a part of works in the Japanese Society of Renal Rehabilitation, and created a guideline in accordance to the “Minds Handbook for Clinical Practice Guideline Development 2014”. Here, we report systematic reviews and recommendations of exercise therapies in patients with kidney diseases based on the guideline preparation committee works. Six recommendations for the condition of each kidney disorder, groups addressing nephritis/nephrosis, chronic kidney diseases, dialysis therapy, and kidney transplantation were created. All the recommendation grades were determined by a consensus conference participated in by representatives of patients and various professionals. The purpose of this report is to provide an evidence-based, best practice summary to optimize the quality, safety and efficacy, and availability of renal rehabilitation service, and to provide care for maximum patient prognosis, quality of life, and satisfaction.

In the early stage of diabetic nephropathy (one of the major microvascular complications of diabetes) glomerular hyperfiltration and hypertrophy are observed. It is clinically important to regulate glomerular hypertrophy for preventing glomerulosclerosis. The number of glomerular endothelial cells is known to be increased in diabetic nephropathy associated with enlarged glomerular tufts, suggesting that the mechanism is similar to that of angiogenesis. Tumstatin peptide is an angiogenesis inhibitor derived from type IV collagen and inhibits in vivo neovascularization induced by vascular endothelial growth factor (VEGF), one of the mediators of glomerular hypertrophy in diabetic nephropathy. Here, we show the effect of tumstatin peptide in inhibiting alterations in early diabetic nephropathy. Glomerular hypertrophy, hyperfiltration, and albuminuria were suppressed by tumstatin peptide (1 mg/kg) in streptozotocin-induced diabetic mice. Glomerular matrix expansion, the increase of total glomerular cell number and glomerular endothelial cells (CD31 positive), and monocyte/macrophage accumulation was inhibited by tumstatin peptide. Increase in renal expression of VEGF, flk-1, and angiopoietin-2, an antagonist of angiopoietin-1, was inhibited by tumstatin treatment in diabetic mice. Alteration of glomerular nephrin expression, a podocyte protein crucial for maintaining glomerular filtration barrier, was recovered by tumstatin in diabetic mice. Taken together, these results demonstrate the potential use of antiangiogenic tumstatin peptide as a novel therapeutic agent in early diabetic nephropathy.