Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan.
Clin Exp Nephrol. 2012 Jun;16(3):442-7. doi: 10.1007/s10157-011-0582-2. Epub 2012 Feb 18.
Klotho has been investigated as an anti-aging protein that is predominantly expressed in the distal convoluted tubules in the kidneys and in the choroid plexus of the brain. The purpose of the present study was to determine the relationship between the soluble form of Klotho and renal function in chronic peritoneal dialysis (PD) patients, a relationship which remains poorly understood.
The soluble Klotho levels in the serum, urine, and peritoneal dialysate obtained from thirty-six PD patients were determined by a sandwich enzyme-linked immunosorbent assay system.
The amount of urinary excreted soluble Klotho over 24 h ranged from 1.54 to 1774.4 ng/day (median 303.2 ng/day; interquartile range [IR] 84.1-498.5), while the serum soluble Klotho concentration ranged from 194.4 to 990.4 pg/ml (mean 553.7 ± 210.4 pg/ml). The amount of urinary Klotho excretion was significantly correlated with residual renal function. However, there was no apparent correlation between the serum soluble Klotho levels and the residual renal function. Klotho was also detected in the 24-h dialysate collections. There was a significant correlation between the peritoneal Klotho excretion and the amount of albumin contained in the dialysate collections (r = 0.798, p < 0.01).
The total amount of urinary excreted Klotho, but not the serum level of soluble Klotho, may be a potential biomarker for assessing the residual renal function among PD patients. Whether our findings are also valid for chronic kidney disease patients overall should therefore be evaluated in greater detail.
Klotho 已被研究为一种抗衰老蛋白，主要在肾脏的远曲小管和脑的脉络丛中表达。本研究的目的是确定可溶性 Klotho 与慢性腹膜透析（PD）患者肾功能之间的关系，这种关系尚未得到充分理解。
采用夹心酶联免疫吸附试验系统检测 36 例 PD 患者血清、尿液和腹膜透析液中可溶性 Klotho 的水平。
24 小时内尿中 Klotho 的排泄量为 1.54 至 1774.4ng/天（中位数 303.2ng/天；四分位距[IR] 84.1-498.5），而血清可溶性 Klotho 浓度为 194.4 至 990.4pg/ml（平均值 553.7±210.4pg/ml）。尿 Klotho 排泄量与残余肾功能显著相关。然而，血清可溶性 Klotho 水平与残余肾功能之间似乎没有明显的相关性。Klotho 也在 24 小时透析液收集物中被检测到。腹膜 Klotho 排泄量与透析液收集物中白蛋白含量之间存在显著相关性（r = 0.798，p <0.01）。
尿中 Klotho 的总排泄量，而不是血清可溶性 Klotho 水平，可能是评估 PD 患者残余肾功能的潜在生物标志物。因此，应更详细地评估我们的发现是否也适用于所有慢性肾脏病患者。
