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Background: The importance of the ratio of creatinine to urinary protein, albumin, and low-molecular weight protein as a urinary marker in chronic kidney disease patients is widely recognized. However, no reference values have hitherto been established for these markers in Japanese children. The present study aimed to establish the reference values for these urinary markers in Japanese children. Methods: The first morning urine was randomly collected from 1712 pupils aged ≥ 3 to < 18 years during school and kindergarten mass urinary screenings. The upper limit of the reference values was set at the 97.5th percentile of the creatinine ratio per marker. Results: The urinary protein-to-creatinine ratio (PCR), urinary albumin-to-creatinine ratio (ACR), urinary beta 2-microglobulin-to-creatinine ratio (BMCR), and urinary alpha 1-microglobulin-to-creatinine ratio (AMCR) showed an age-related decrease at the 50th percentile reflecting an age-related increase in urinary creatinine. The appropriate reference value for the PCR and ACR was 0.12 g/gCr and 35 mg/gCr, respectively, in the entire cohort. The appropriate reference value for the BMCR was 0.5 μg /mgCr for age ≥ 3 to < 6 years and 0.35 μg/mgCr for age 6 years or older. The appropriate reference value for the AMCR was 5.0 μg/mgCr for age ≥ 3 to < 6 years and 3.5 μg /mgCr for age 6 years or older. Conclusion: The present study was the first to determine appropriate reference values for the PCR, ACR, BMCR, and AMCR based on an analysis of the first morning urine samples of a large number of children. [ABSTRACT FROM AUTHOR]

Background: Hyperuricemia is a known risk factor for end-stage renal disease. Although xanthine oxidase (XO) inhibitors are expected to protect the kidney function, evidence to this end is insufficient at present. Methods: This study was a multi-center, open-labeled, randomized study conducted in Mie Prefecture in Japan. Patients were included if they were between 20 and 80 years old and had a serum uric acid (sUA) level ≥ 7.0 mg/dl with or without gout, estimated glomerular filtration rate (eGFR) of 15–60 ml/min/1.73 m2, and urinary protein creatinine ratio (uPCR) of 0.15–3.5 g/gCr. Patients were randomly assigned to a Topiroxostat or Febuxostat group, and the treatment target for the sUA level was < 6.0 mg/dl. The primary outcome was the change in the uPCR after 24 weeks. Results: The change in the median uPCR after 24 weeks was not statistically significant after treatment in the Topiroxostat or Febuxostat group (0.05 g/gCr and − 0.04 g/gCr, respectively). However, the sUA levels decreased significantly in both groups (Topiroxostat group: 8.6 ± 1.1 at baseline to 6.0 ± 1.1 mg/dl at 24 weeks, Febuxostat group: 8.4 ± 1.1 mg/dl at baseline to 5.9 ± 1.3 mg/dl at 24 weeks). No significant change in the eGFR after 24 weeks was noted in either the Topiroxostat or Febuxostat group (− 0.04 ± 4.59 ml/min/1.73 m2 and 0.31 ± 4.70 ml/min/1.73 m2, respectively). Conclusions: In this study, XO inhibitors did not significantly reduce the uPCR in chronic kidney disease stage 3 and 4 patients with hyperuricemia. [ABSTRACT FROM AUTHOR]

Background: The urinary protein/creatinine ratio [Up/Ucr (g/gCr)] has been used in the clinical management of patients with chronic kidney disease (CKD). However, a discrepancy is often noted between the Up/Ucr and 24-h urinary protein excretion [24hUp (g/day)] in patients with extremes of muscle mass. We examined devised a method for precise estimation of the 24-h urinary protein excretion (E-24hUp) based on estimation of 24-h urinary creatinine output (E-24hCr). Methods: Three parameters, spot Up/Ucr, 24hUP and E-24hUp (=Up/Ucr × E-24hCr), were determined in 116 adult patients with CKD. The correlations among the groups were analyzed. Results: There was a significant correlation between the Up/Ucr and 24hUp ( p < 0.001). We divided the patients into three groups according to the 24hUp; the low urinary protein group (<1.0 g/day), the intermediate urinary protein group (1.0-3.5 g/day), and the high urinary protein group (>3.5 g/day). There was a significant correlation between the Up/Ucr and 24hUp in the low ( p = 0.04) and high urinary protein ( p = 0.01) groups, whereas the correlation coefficient was lower in the intermediate urinary protein ( p = 0.07) group. Thus, we found a significant correlation between 24hUp and E-24hUp in the study population overall ( p < 0.001), in the low ( p = 0.01), in the intermediate ( p < 0.001), and in the high urinary protein group ( p < 0.001). Conclusion: We conclude that a poor correlation exists between the Up/Ucr and 24hUp in patients with intermediate urinary protein excretion levels. The recommended parameter for monitoring proteinuria in such patients may be the E-24hUp, which is calculated using the E-24hCr. [ABSTRACT FROM AUTHOR]

Background: Na/Ca exchanger 1 (NCX1) controls intracellular Ca concentration in various cell types. In the kidney, NCX1 is expressed mainly in the distal tubular basolateral membrane as well as in vascular smooth muscle. Tubular NCX1 is involved in Ca reabsorption, and NCX1 in renal arterioles may control intraglomerular pressure. However, the functions of renal NCX1 have not been studied in vivo. Therefore, this study examined the effects of renal NCX1 blockade on water and solute metabolism, renal function and blood pressure in rats. Methods: Wistar-Kyoto rats were uninephrectomized, and an osmotic mini pump was implanted to infuse the remnant kidney cortex with a specific NCX1 inhibitor, SEA0400 (SEA), or vehicle for 7 days. Results: Serum Ca concentration and urinary Ca excretion were similar between the vehicle- and SEA-treated groups. However, serum phosphate was significantly decreased by 8 % in the SEA group, with similar urinary phosphate excretion between the two groups. Systolic blood pressure was higher in the SEA group (117 ± 3 vs. 126 ± 1 mmHg, n = 9-11), with a 1.6-fold increase in plasma aldosterone concentration. However, SEA significantly reduced urinary protein excretion and the glomerular sectional area by 16 and 8 %, respectively. Similar experiment in spontaneously hypertensive rats produced different results. Conclusion: Renal SEA treatment reduced serum phosphate concentration, urinary protein and glomerular size with higher systemic blood pressure compared to control Wistar-Kyoto rats. Further study on renal NCX1 may be beneficial in delineating the pathophysiology of glomerular pressure control and calcium/phosphate regulations. [ABSTRACT FROM AUTHOR]

Background: Although the cardiorenal relationship in chronic kidney disease has been investigated, information about the lung−kidney relationship is limited. Here, we investigated the impact of kidney function and urinary protein excretion on pulmonary dysfunction. Methods: The data from pulmonary function tests and kidney function (estimated glomerular filtration rate [eGFR] and urinary protein) between 1 April 2005 and 30 June 2010 were selected from our laboratory database. Data were classified into 4 categories according to eGFR and proteinuria. Category 1, eGFR ≥60 ml/min/1.73 m and urinary protein <0.3 g/gCr; category 2, eGFR <60 ml/min/1.73 m and urinary protein <0.3 g/gCr; category 3, eGFR ≥60 ml/min/1.73 m and urinary protein ≥0.3 g/gCr; and category 4, eGFR <60 ml/min/1.73 m and urinary protein ≥0.3 g/gCr. Pulmonary function data were evaluated according to these 4 categories. Results: A total of 133 participants without major respiratory disease, abnormal computed tomography and smoking history were enrolled. Hemoglobin (Hb)-adjusted percentage carbon monoxide diffusing capacity (%DL) in category 4 (46.2 ± 7.5) and category 2 (63.6 ± 17.8) were significantly lower than in category 1 (75.8 ± 18.9) ( P < 0.05). In addition, Hb-adjusted %DL was weakly correlated with eGFR in participants with urinary protein <0.3 g/gCr ( R = 0.30, P = 0.001). Hb-adjusted %DL was strongly correlated with eGFR in participants with urinary protein ≥0.3 g/gCr ( R = 0.81, P < 0.001). Other pulmonary function test markers (percentage (%) vital capacity, % forced expiratory volume in one second (FEV1), FEV1/forced vital capacity, % total lung capacity, and % residual volume) were not significantly different between categories. Conclusion: This study suggests that decreased eGFR is associated with decreased %DL in proteinuric patients. [ABSTRACT FROM AUTHOR]

Background. Angiotensin-converting enzyme inhibitors (ACE-Is) are important agents for preserving renal function in patients with renal diseases. However, the choice of which ACE-I to employ for the treatment of renal disease has not yet been clarified. This study compared the renal effects of enalapril with those of five other ACE-Is in patients with chronic renal diseases. Methods. One hundred and twenty-eight patients with various renal diseases were randomly assigned to six groups according to the ACE-I used: group 1, alacepril (75 mg/day; n = 20); group 2, captopril (37.5 mg/day; n = 19); group 3, cilazapril (1.0 mg/day; n = 23); group 4, delapril (30 mg/day; n = 22); group 5, enalapril (5.0 mg/day; n = 20); and group 6, temocapril (2.0 mg/day; n = 24). Doses of the ACE-I adjusted-converting to the renal function showed similar effects in decreasing blood pressure. Each ACE-I was administered to the patients for 4 months, with monthly examinations. Twenty-four patients dropped out, for various reasons; therefore, results for 104 patients were finally analyzed (group 1, n = 16; group 2, n = 11; group 3, n = 22; group 4, n = 21; group 5, n = 12; group 6, n = 22). Results. There were no differences in absolute or percent changes in mean arterial pressure (MAP), plasma aldosterone (ALDO), the urinary excretion of protein (U-P) and albumin (U-ALB), 24-h creatinine clearance (24-h Ccr), plasma renin activity (PRA), and serum potassium (K) between enalapril and the other ACE-Is, although significant decreases from baseline values in MAP, ALDO, U-P, U-ALB, and 24-h Ccr, and increases in PRA and serum K from baseline values were observed after the administration of enalapril and the other ACE-Is. Conclusions. These results indicated that the renal effects of enalapril were similar to those of the other ACE-Is tested, and suggested, therefore, that any one of the class of ACE-Is could be chosen with the choice being dependent on that considered to lead to best compliance for the patient. The beneficial effects of the class of ACE-Is in patients with renal disease would be expected to be similar. [ABSTRACT FROM AUTHOR]