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Gitelman syndrome is an autosomal recessive genetic disease caused by pathogenic variants in SLC12A3 resulting in the loss of function of the Na–Cl co-transporter (NCC) in the distal tubules. Hypokalemia and diuretic effects can cause secondary type 2 diabetes and renal function decline. Here, we present the case of a 49-year-old male patient with chronic persistent treatment-resistant hypokalemia for the past 13 years who had been receiving treatment for type 2 diabetes mellitus for 6 years. He was referred to our department due to the presence of urinary protein, impaired renal function, high renin activity, and hyperaldosteronism. Laboratory test results showed hypokalemia, hypomagnesemia, hypocalciuria, and metabolic alkalosis. Using next-generation and Sanger sequencing, we identified a novel stop-gain variant (NM_000339.3:c.137del [p.His47fs]) and a missense variant (NM_000339.3:c.2927C > T [p.Ser976Phe]) in the SLC12A3 gene. This novel pathogenic variant was located at the intracellular N-terminus of the NCC. Based on these findings, the patient was diagnosed with Gitelman syndrome. The use of next-generation sequencing facilitated the exclusion of diseases with similar clinical symptoms.

Hematuria is the first manifestation of urinary abnormality in immunoglobulin A nephropathy (IgAN). Hematuria has recently been reported as a risk factor for deterioration of renal function; however, its cause remains unknown.We analyzed the surface marker of peripheral blood mononuclear cells before and immediately after tonsillectomy in IgAN patients and controls (chronic tonsillitis or tonsillar hypertrophy) by flow cytometry and investigated the association with hematuria. To prove our hypothesis that NK cells induce hematuria, we administered IL-12, activator of NK cells, to HIGA mice. In addition, we transferred cultured NK cells to nude rats and transferred the CD16(+)CD56(+) cells, including NK cells, that are derived from the peripheral blood of IgAN patients immediately after tonsillectomy to nude rats to assess the hematuria level and renal histology of the recipients. We also performed cytotoxicity assays against glomerular endothelial cells by NK cells.We found that IgAN patients who showed rapid deterioration of hematuria after tonsillectomy also displayed a significant increase in CD16(+)CD56(+) cells in the peripheral blood immediately after tonsillectomy. Exogenous administration of IL-12 to HIGA mice induced hematuria. Adoptive transfer of either cells of an NK cell line, or of CD16(+)CD56(+) cells derived from IgAN patients, into nude rats induced hematuria in the recipients. In vitro analysis showed that NK cells exert cytotoxic activity toward human glomerular endothelial cells in a dose-dependent manner.CD16(+)CD56(+) cells seem to be responsible for hematuria in IgAN.

Background. As a cardiorenal syndrome, there is a dynamic interplay between the heart and the kidney. We conducted a prospective study to evaluate the prognostic impact of plasma B-type natriuretic peptide (BNP) level, a cardiac biomarker, on the long-term kidney prognosis in chronic kidney disease (CKD) patients. Methods. We prospectively enrolled 508 patients with CKD Stages 3, 4 and 5 not on dialysis, from a single nephrology department between 2004 and 2010. The exclusion criteria were over 90 years of age, malignancy, active infection, low cardiac ejection fraction and rapid progressive glomerulonephritis. Relationships between BNP and kidney end point [defined as doubling of baseline serum creatinine and end-stage kidney disease (ESKD) requiring kidney replacement therapy] were measured using Cox models for case-mix and laboratory variables. Results. The final analysis covered 485 participants with no loss to follow-up. The median follow-up period was 3.2 years. Two hundred and twenty-eight of the 485 patients reached ESKD requiring dialysis, and baseline serum creatinine levels doubled in another 31. The kidney end point was significantly poorer among patients with plasma BNP levels above, compared with below a cut-off value of 86.1 pg/mL indicated from receiver operating characteristic analysis. Multivariable Cox regression analysis identified the common logarithm BNP as a predictor of kidney end point (adjusted hazard ratio 1.78, 95% CI: 1.28–2.46, P < 0.01). Conclusions. Elevation of BNP level is associated with an increased risk for accelerated progression of CKD ultimately to ESKD. Monitoring the BNP level could be helpful in the management of combined heart and kidney disease.

Background. The quality of dialysis care provided by specialists is expected to be superior to that by nonspecialists. However, little is known about the actual effect of specialist care on long-term prognosis in dialysis patients. We sought to determine whether specialist care can actually be associated with better survival rates in a nationwide Japanese dialysis cohort. Methods. The Japanese Society for Dialysis Therapy (JSDT) has annually reported clinical and demographic variables of dialysis patients for each prefecture in Japan since 1983. We analysed the data for the 47 prefectures from 1983 to 2006 to evaluate the relationship between the proportion of specialists and the cumulative survival rates for 5-year periods. Results. Trend analyses revealed that a higher quintile of specialists was associated with a better cumulative survival rate at 5-, 10-, 15- and 20-year periods. Univariate analyses for the 47 prefectures showed a higher proportion of specialists to be correlated with a better cumulative survival at 10-, 15- and 20-year periods. Multivariate analyses revealed that the proportion of specialists persisted as an independent contributor for better survival at 10-, 15- and 20-year periods even after adjustment for age, sex, diabetes mellitus and socioeconomical status, while the survival rate at 5 years was at a nonsignificant level. Conclusions. While our study should be confirmed using data for individuals, this was not possible due to privacy issues. Therefore, based on our current findings, we conclude that for patients on maintenance dialysis, specialist care can be associated with better survival rates, particularly with longer follow-up.

Background/Aims: Little information is available concerning the effectiveness of plasma exchange for progressive liver failure in liver transplant recipients. The aims of the present study were to evaluate the effectiveness of plasma exchange and discuss its indication. Methods: Forty-six ABO-compatible recipients of living-related liver transplants operated on in Osaka University hospital were retrospectively studied. Results: Total bilirubin was identified as the most accurate predictor of the short-term prognosis of 46 recipients (optimal cut-off point: 13.3 mg/dl). Eleven patients received 14 plasma exchange sessions. Elevation of total bilirubin was significantly suppressed after plasma exchange in the patients with total bilirubin below the median (24 mg/dl), whereas total bilirubin significantly increased even after plasma exchange in those with total bilirubin above the median. Conclusion: Plasma exchange improved liver function in recipients with progressive liver failure and appears to be indicated in patients with total bilirubin levels ranging between 13 and 24 mg/dl.

Background: The accuracy for the detection of coronary stenosis by multidetector row computed tomography (MDCT) has been getting more recognition. However, the usefulness of MDCT in patients with chronic kidney disease (CKD) has not been confirmed. Methods: Weanalyzed 19 consecutive patients with asymptomatic diabetic CKD who underwent both MDCT and coronary angiography (CAG) at the initiation of dialysis. The definition of stenosis in this study was lesions with ≧50% stenosis by CAG. Results: CAG revealed stenosis in 35 of 76 branches in 19 patients. Vessel diameter could not be evaluated by MDCT in 11 (14%) major vessels because of motion artifacts, pericardial effusion, pleural effusion, and severe calcification. Almost all of such lesions were located in the right coronary (4/11; 36%) or left circumflex (5/11; 45%) artery. The sensitivity, specificity, positive and negative predictive values of MDCT for a diagnosis of stenosis in the 65 evaluable major vessels were 86, 81, 78, and 88%, respectively. The severity of vessel calcification was increased in a stepwise manner with increments in the proportion of major vessels with ≧50% stenosis (p = 0.004 for trend). Conclusion: MDCT seemed to be an effective non-invasive method of screening patients with diabetic CKD for CAD.

Background. The high prevalence of asymptomatic coronary artery stenosis (CAS) in chronic kidney disease (CKD) has emerged as an important predictor of outcome. However, diagnostic tools that can identify asymptomatic CAS have not yet been established. We investigated whether asymptomatic patients at the initiation of renal replacement therapy (RRT) could be screened using cardiac troponin T (cTnT) and atherosclerotic surrogate markers such as ankle-brachial blood pressure index (ABPI) and intimamedia thickness (IMT). Methods and results. Among 142 patients who were about to start RRT, 60 who were asymptomatic underwent coronary evaluation by multi-slice computed tomography (MSCT) and/or coronary angiography (CAG). CAG diagnosed 35 patients (43.8%) as CAS positive and 27 of them had multi-vessel disease. Factors associated with CAS were smoking, elevated cTnT, low ABPI and high IMT. Moreover, the severity of CAS was associated with smoking, cTnT and ABPI. Stepwise logistic regression analyses revealed that cTnT was a powerful predictor of asymptomatic multi-vessel CAS. Receiver operating characteristic analysis documented the usefulness of cTnT as a screening tool with a cut-off point 0.05 ng/ml. The optimal screening tool for multi-vessel CAS was cTnT (sensitivity, 92.6%; 95% CI, 82.7–99.9; specificity, 63.6%; 95% CI, 47.2–80.0). Conclusion. We concluded that cTnT should be measured as part of a strategy for detecting asymptomatic CAS, especially multi-vessel disease in patients with CKD at the start of RRT.

Background Erythropoietin (EPO) has been reported to slow the decline of renal function in predialysis chronic kidney disease (CKD) patients. On the contrary, in the recent large-scale randomized controlled trial (RCT), CREATE and CHOIR, which aimed to keep a higher haemoglobin (Hb) level than former trials, the renoprotective effect of EPO was not observed. Today, the renoprotective effect of EPO has become controversial. In order to test the hypothesis that the usage of EPO in predialysis CKD patients may ameliorate the progression of renal disease, we conducted a macro-level observational study dealing with all Japanese predialysis CKD patients. Methods Annually since 1982, the Japanese Society for Dialysis Therapy reports the number of patients that have entered maintenance dialysis in each prefecture of Japan. Based on the 2002-2004 data, we calculated the annual incidence of end-stage renal disease (ESRD) in each of the 47 prefectures. The annual amounts paid for EPO by each prefecture, presumably corresponding to the amounts used, corrected for the estimated predialysis CKD patients, were calculated. We examined the relationship between the incidence of new dialysis and the usage of EPO in each prefecture. Furthermore, the usage of EPO was compared with that of antihypertensive agents including angiotensin converting enzyme inhibitor (ACE-I), and that of statin. Results There were prefectural differences in the annual incidence of ESRD from 2002 to 2004. We also found prefectural differences in the usage of EPO for the three consecutive years. The usage of EPO in predialysis patients was negatively correlated with the incidence of ESRD on linear and multiple regression analyses. At the same time, the usage of EPO had strong positive correlations with the usage of antihypertensive agents including ACE-I and with that of statin. Conclusion Our nationwide epidemiologic study revealed that a higher use of EPO was associated with a decreased incidence of new dialysis in daily clinical practice. In addition, there were strong correlations among the usage of EPO, antihypertensive agents and statin. These data are supportive of, but do not prove, the hypothesis that EPO may be renoprotective, when used in combination with other strategies.

IgA nephropathy (IgAN) is the most common primary glomerulonephritis. Its close relation with the tonsils is well known because tonsillitis sometimes causes aggravation of urinary findings or macrohematuria. However, the genes specific to the tonsils of IgAN patients are not clarified. To clarify the specific gene expression in the tonsils of IgAN patients, we performed tonsillectomy and corticosteroid IV therapy as a treatment of IgAN, analyzed the gene expression in the tonsils by microarray and compared it with that in tonsils from chronic tonsillitis patients. The upregulated genes seem to be categorized into two groups: muscle-related genes and immunerelated genes. The downregulated genes include the polymeric Ig receptor (pIgR) which was reportedly involved in single nucleotide polymorphism (SNP) of Japanese IgAN patients.

Background Recently, combination of tonsillectomy and steroid pulse therapy was reported to be effective as the treatment of the immunoglobulin A nephropathy (IgAN). However, the gene expression difference between the tonsils in patients with IgAN and those in control patients is not established. Methods We performed tonsillectomy combined with steroid pulse as a treatment to IgAN, analyzed the gene expression in the tonsils (N = 23) using microarray, compared with those with patients suffering from chronic tonsillitis (N = 22). From some candidate genes related with IgAN, we confirmed the apolipoprotein B messenger RNA-editing enzyme catalytic polypeptides 2 (APOBEC2) gene expression in the tonsil and we also analyzed its expression levels and clinical features. Results Up-regulated genes seem to be categorized into two groups. One group belongs to the muscle related genes which might be caused by structural differences. The other group includes the immune system-related genes, such as APOBEC2, CALB2, DUSP27, and CXCL11. APOBEC2 was positively stained in the epithelium and the peripheral region of the germinal center in both tonsils. APOBEC2 expression level was negatively related with serum igg level, but did not correlate with clinical course after tonsillectomy. Conclusion We confirmed gene expression differences related with immune system and muscle structure. The APOBEC2 was confirmed to be elevated in the tonsils with IgAN patients, and the gene expression level was negatively related with serum igg level in overall patients. These results might be helpful to reveal the mechanism of IgAN.

Background: Type IV collagen is one of the major components of basement membrane. In diabetic nephropathy, it is already known that urinary excretion of type IV collagen increases with the disease progression. However, in nondiabetic kidney disease, urinary type IV collagen (u-IVc) levels have not been extensively investigated. The aim of this study was to evaluate u-IVc levels in various nephropathies except diabetic nephropathy. Methods: u-IVc levels were measured cross-sectionally from 527 biopsy-proven nondiabetic renal disease patients at tertiary care hospitals by one-step sandwich enzyme immunoassay. Results: On simple regression analyses, u-IVc levels had positive correlation with age, blood pressure, urinary protein (u-Prot), urinary β2 microglobulin, urinary N-acetyl-β-D-glucosaminidase, HbA1c, and selectivity index (SI), while u-IVc had negative correlation with eGFR and serum albumin. Multiple regression analyses revealed that u-IVc was positively correlated with u-Prot, HbA1c and SI. Among biopsy-proven nondiabetic nephropathies, elevation of u-IVc was distinctively observed in membranous nephropathy and anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis. Conclusion: u-IVc levels were elevated with the increase in u-Prot, HbA1c and SI. In addition, among nondiabetic kidney disease, elevation of u-IVc was observed in patients with membranous nephropathy and ANCA, which might reflect the thickening of basement membrane or severe kidney damage.

We report a case of a 17-year-old boy suffering from severe loin pain and oliguric acute kidney injury after strenuous exercise, with slightly elevated serum myoglobin and creatinine phosphokinase. Exercise-induced acute kidney injury (AKI) was diagnosed. We started intermittent hemodialysis thrice a week from the admission day. Four days later, he temporally lost consciousness, followed by visual agnosia and general clonic seizure. T2-weighted brain magnetic resonance images (MRI) showed multiple areas of increased signal intensity in the subcortical white matter, predominantly in the cerebrum of the posterior and parietal lobes and in the cerebellum. Clinical symptoms improved without sequelae. Follow-up MRI 1 month later showed complete resolution of the signals, and he was diagnosed with reversible posterior leukoencephalopathy syndrome (RPLS). This is the first reported case of exercise-induced AKI associated with RPLS. Vasoconstriction and endothelial dysfunction are considered as the common etiology of these diseases.

BackgroundImmunoglobulin (Ig)A nephropathy (IgAN) is the most common form of primary glomerulonephritis in the world. Some bacteria were reported to be the candidate of the antigen or the pathogenesis of IgAN, but systematic analysis of bacterial flora in tonsil with IgAN has not been reported. Moreover, these bacteria specific to IgAN might be candidate for the indicator which can predict the remission of IgAN treated by the combination of tonsillectomy and steroid pulse.Methods and findingsWe made a comprehensive analysis of tonsil flora in 68 IgAN patients and 28 control patients using Denaturing gradient gel electrophoresis methods. We also analyzed the relationship between several bacteria specific to the IgAN and the prognosis of the IgAN. Treponema sp. were identified in 24% IgAN patients, while in 7% control patients (P = 0.062). Haemophilus segnis were detected in 53% IgAN patients, while in 25% control patients (P = 0.012). Campylobacter rectus were identified in 49% IgAN patients, while in 14% control patients (P = 0.002). Multiple Cox proportional-hazards model revealed that Treponema sp. or Campylobactor rectus are significant for the remission of proteinuria (Hazard ratio 2.35, p = 0.019). There was significant difference in remission rates between IgAN patients with Treponema sp. and those without the bacterium (p = 0.046), and in remission rates between IgAN patients with Campylobacter rectus and those without the bacterium (p = 0.037) by Kaplan-Meier analysis. Those bacteria are well known to be related with the periodontal disease. Periodontal bacteria has known to cause immune reaction and many diseases, and also might cause IgA nephropathy.ConclusionThis insight into IgAN might be useful for diagnosis of the IgAN patients and the decision of treatment of IgAN.