Guidelines for clinical evaluation of chronic kidney disease in early stages : AMED research on regulatory science of pharmaceuticals and medical devices.

BACKGROUND: For the development of pharmaceutical products in kidney field, appropriate surrogate endpoints which can predict long-term prognosis are needed as an alternative to hard endpoints, such as end-stage kidney disease. Though international workshop has proposed estimated glomerular filtration rate (GFR) slope reduction of 0.5-1.0 mL/min/1.73 m /year and 30% decrease in albuminuria/proteinuria as surrogate endpoints in early and advanced chronic kidney disease (CKD), it was not clear whether these are applicable to Japanese patients. METHODS: We analyzed J-CKD-DB and CKD-JAC, Japanese databases/cohorts of CKD patients, and J-DREAMS, a Japanese database of patients with diabetes mellitus to investigate the applicability of eGFR slope and albuminuria/proteinuria to the Japanese population. Systematic review on those endpoints was also conducted including the results of clinical trials published after the above proposal. RESULTS: Our analysis showed an association between eGFR slope and the risk of end-stage kidney disease. A 30% decrease in albuminuria/proteinuria over 2 years corresponded to a 20% decrease in the risk of end-stage kidney disease patients with baseline UACR ≥ 30 mg/gCre or UPCR ≥ 0.15 g/gCre in the analysis of CKD-JAC, though this analysis was not performed on the other database/cohort. Those results suggested similar trends to those of the systematic review. CONCLUSION: The results suggested that eGFR slope and decreased albuminuria/proteinuria may be used as a surrogate endpoint in clinical trials for early CKD (including diabetic kidney disease) in Japanese population, though its validity and cutoff values must be carefully considered based on the latest evidence and other factors.

Effect of dapagliflozin on the initial estimated glomerular filtration rate dip in chronic kidney disease patients without diabetes mellitus.

BACKGROUND: Dapagliflozin (DAPA), a sodium-glucose transporter 2 inhibitor (SGLT2i), attenuates kidney outcomes in patients with not only diabetes mellitus (DM) but also chronic kidney disease (CKD). SGLT2i-derived initial dip in estimated glomerular filtration rate (eGFR) has been considered to reduce excess glomerular pressure, followed by renal protection in patients with DM. However, whether DAPA confers the eGFR dip and its independent determinants for CKD patients without DM are unclear. METHODS: A total of 126 patients with CKD treated with 10 mg DAPA daily was retrospectively registered. After participants with missing data and DM were excluded, 51 participants were enrolled. RESULTS: An initial eGFR dip was observed 1 month after initiation of DAPA, which was sustained until 2 months. DAPA did not affect urinary protein excretion; however, serum uric acid was decreased, while hemoglobin level was increased. Multiple regression analysis revealed that eGFR at baseline was the only independent determinant of the initial dip of eGFR. The patients currently showing exacerbation of glomerular hyperfiltration exhibited the larger initial eGFR dip rather than those showing progressive renal dysfunction. The patients meeting exclusion criteria of DAPA-CKD trial exhibited same degree of the initial eGFR dip as others. CONCLUSIONS: DAPA causes an initial dip of eGFR in CKD patients without DM at 1 month after starting DAPA treatment. A higher eGFR at baseline predicts a large initial eGFR dip, which might be linked to the subsequent recovery in eGFR in CKD patients without DM.

A nationwide cross-sectional analysis of biopsy-proven Fabry nephropathy: the Japan Renal Biopsy Registry.

BACKGROUND: Fabry disease (FD) is an X-linked inherited disease where renal complications are associated with a poor prognosis. However, little is known about the prevalence of Fabry nephropathy (FN) in patients with chronic kidney disease (CKD). We extracted FN data from the Japan Renal Biopsy Registry, analyzed the prevalence of FN, and examined the correlation between clinical characteristics and renal involvement according to sex differences and hemi- and heterozygosity in patients with FD. METHODS: A total of 38,351 participants who underwent renal biopsy were retrospectively enrolled, and FN was determined. The clinical characteristics of FD patients were examined based on sex differences. RESULTS: Twenty-nine patients (0.076%) (19 males and 10 females, mean age: 43.7 ± 15.5 years old) were diagnosed with FN. Median estimated urinary protein (UP) and mean eGFR levels were 0.9 [interquartile range (IQR) [0.7-1.6] g/gCr and 67.1 ± 36.8 mL/min/1.73 m2, respectively. Mean systolic blood pressure (SBP) was 126.4 ± 17.1 mmHg and diastolic blood pressure was 76.1 ± 12.6 mmHg. An inverse correlation between eGFR and logarithm UP levels was observed (r2 = 0.23, p = 0.02), SBP was positively associated with logarithm UP (r2 = 0.34, p = 0.004) overall and inversely associated with eGFR (r2 = 0.25, p = 0.007) regardless of sex, and SBP was an independent determinant of proteinuria (p = 0.004) and eGFR (p = 0.007). CONCLUSIONS: The prevalence of biopsy-proven FN was 0.076%. Since SBP is associated with eGFR regardless of zygosity, strict SBP control might be necessary to prevent progression to end-stage kidney disease in both male and female patients with FN.

Association of Baseline Renal Function with Mortality in Patients with Sepsis Requiring Continuous Renal Replacement Therapy for Acute Kidney Injury: A Single-Center Retrospective Study.

INTRODUCTION: To date, the prognosis of patients with sepsis and underlying chronic kidney disease (CKD) had been poor. However, the impact of preseptic renal function on the short-term prognosis of patients with extremely severe septic shock with acute kidney injury (AKI) that requires renal replacement therapy (RRT) is unclear. METHODS: Of the septic shock cases treated at the intensive care unit for ≥48 h, 131 adults who were diagnosed as septic AKI and underwent continuous venovenous hemodiafiltration were retrospectively analyzed. The relationships of demographic, clinical, and laboratory data with mortality were evaluated, and the independent risk factors for death were identified. RESULTS: The median age of the subjects was 73 (range, 63-80) years, and 76 (58%) were men. The rate of mortality was significantly higher among patients with CKD (n = 42) than in those without CKD (n = 89) (43% vs. 22%, p < 0.016). On univariate and multivariate logistic regression analyses, the associated factors and independent predictors of death were Sequential Organ Failure Assessment score (odds ratios [ORs] 1.151, 95% confidence intervals [CIs] 1.026-1.293, p = 0.017, and OR 1.129, 95% CI 1.003-1.271, respectively); baseline estimated glomerular filtration rate (OR 0.986, 95% CI 0.975-0.997, p = 0.016, and OR 0.983, 95% CI 0.970-0.996, respectively); and lactic acid (OR 1.094, 95% CI 1.005-1.190, p = 0.038, and OR 1.110 CI 1.015-1.215, respectively). CONCLUSION: Reduced baseline renal function may be a factor for poor short-term prognosis in severe septic AKI cases requiring RRT.

New Estimation Formulas for Daily Sodium Intake in Hemodialysis Patients by a Duplicate Portion Method.

OBJECTIVE: Excess sodium intake is associated with volume overload and increased blood pressure. Therefore, to prevent future cardiovascular events, a sodium-restricted diet is strongly recommended for patients on maintenance hemodialysis (HD). However, only one formula for estimating dietary sodium intake in HD patients is available, and its validity has not been adequately evaluated. This study aimed to measure daily sodium intake using the duplicate portion method and provide a new formula for estimating dietary sodium intake. DESIGN AND METHODS: Nineteen Japanese patients undergoing HD were enrolled in this cross-sectional multicenter study. The daily sodium intake of these patients was measured directly using the duplicate portion method. Two formulas for estimating sodium intake were developed by stepwise regression analysis. Their validities were compared with the validity of the previous formula. Furthermore, using these new formulas, we estimated the daily consumption of sodium in a large number of Japanese HD patients. RESULTS: The previous formula underestimated true sodium intake using Bland-Altman diagrams. No significant correlation was noted between the measured sodium intake and the estimated intake (r = 0.30, P = .23, Fisher's Z-transformation). The new formulas 1 and 2, which included age, predialysis and postdialysis serum sodium levels, predialysis body weight, and interdialytic body weight gain, accurately estimated sodium consumption. The coefficients of correlation between the estimated values and the true sodium intake were r = 0.858 and r = 0.805, respectively. The simulation model using data from the Japanese Society for Dialysis Therapy showed that the distribution of the estimated sodium intake using the previous formula shifted left compared with that using the new formulas. CONCLUSIONS: The new formulas accurately estimated the daily sodium consumption in HD patients. Further longitudinal studies are required to determine whether the estimated sodium intake level calculated using the new formulas would serve as a potential marker and/or therapeutic target to prevent cardiovascular events in HD patients.

Quantification and Visualization of Reliable Hemodynamics Evaluation Based on Non-Contact Arteriovenous Fistula Measurement.

The condition of arteriovenous fistula (AVF) blood flow is typically checked by using auscultation; however, auscultation should require a qualitative judgment dependent on the skills of doctors, and further attention to contact infection is required. For these reasons, this study developed a non-contact and non-invasive medical device to measure the pulse wave of AVFs by applying optical imaging technology. As a first step toward realization of the quantification judgment based on non-contact AVF measurement, we experimentally validated the developed system, whereby the hemodynamics of 168 subjects were visually and quantitatively evaluated based on clinical tests. Based on the evaluation results, the fundamental statistical characteristics of the non-contact measurement, including the average and median values, and distribution of measured signal-to-noise power ratio, were demonstrated. The clinical test results contributed to the future construction of quantified criteria for the AVF condition with the non-contact measurement.

Screening of Fabry disease in patients with chronic kidney disease in Japan.

BACKGROUND: Fabry disease (FD), an X-linked lysosomal storage disorder caused by a deficiency in alfa-galactosidase A (α-Gal A) activity due to mutations in the GLA gene, has a prevalence of 0-1.69% in patients undergoing haemodialysis; however, its prevalence in patients with chronic kidney disease (CKD) Stages 1-5 is unknown. METHODS: Serum α-Gal A activity analysis and direct sequencing of GLA were used to screen for FD in 2122 male patients with CKD, including 1703 patients with CKD Stage 5D and 419 with CKD Stages 1-5. The correlation between serum α-Gal A activity and confounding factors in patients with CKD Stages 1-5 was evaluated. RESULTS: FD prevalence rates in patients with CKD Stage 5D and CKD Stages 1-5 were 0.06% (1/1703) and 0.48% (2/419), respectively. A patient with CKD Stage 5D exhibited a novel GLA mutation, p.Met208Arg, whereas two patients with CKD Stages 1-5 had c.370delG and p.Met296Ile. p. Met208Arg caused moderate structural changes in the molecular surface region near the substituted amino acid residue but did not affect the catalytic residues Asp170 and Asp231 in α-Gal A. Serum α-Gal A activity in patients with CKD Stages 1-5 was inversely correlated with age (P < 0.0001) but directly correlated with estimated glomerular filtration rate (P < 0.0001). CONCLUSIONS: FD prevalence was much higher in male patients with CKD Stages 1-5 than in those with CKD Stage 5D. FD screening in patients with CKD Stages 1-5 may improve patient survival, decreasing the number of patients with CKD Stage 5D.

A new diagnostic indication device of a biomarker growth differentiation factor 15 for mitochondrial diseases: From laboratory to automated inspection.

Mitochondrial diseases (MDs) are occasionally difficult to diagnose. Growth differentiation factor 15 (GDF15) has been reported as a biomarker useful for not only diagnosing MDs, but also evaluating disease severity and therapeutic efficacy. To enable the measurement of serum GDF15 concentrations at medical institutions, we developed a new latex-enhanced turbidimetric immunoassay (LTIA) as an automated diagnostic indication test for MDs. We also examined the equivalency of specificity and sensitivity in measuring serum GDF15 concentrations between a commercially available enzyme-linked immunosorbent assay (ELISA) kit and a novel LTIA device in patients with MDs, disease controls, and healthy controls. A clinical performance study used a newly developed LTIA device and an existing ELISA kit to measure the concentrations of GDF15 in 35 MD patients, 111 disease controls, and 86 healthy controls. The median (first quartile-third quartile) of serum GDF15 concentrations measured with the LTIA device was significantly higher (P < .001) in MD patients (1389.0 U/mL [869.5-1776.0 U/mL]) than in healthy controls (380.5 U/mL [330.2-471.8 U/mL]); the interquartile ranges did not overlap between MD patients and healthy controls. The areas under the curve in disease and healthy controls were 0.812 (95% confidence interval [CI]: 0.734-0.886) and 0.951 (95% CI: 0.910-0.992), respectively. The automated, high-throughput technology-based LTIA device has definite advantages over the ELISA kit in shorter processing time and lower estimated cost per sample measurement. The LTIA device of GDF15 may be a sufficiently reliable, frontline, diagnostic indicator of individuals with suspected MDs in the general population.

Effect of tolvaptan on renal involvement in patients with autosomal dominant polycystic kidney disease according to different gene mutations.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is an inherited disorder caused by mutations in the polycystic kidney disease (PKD) gene. Although tolvaptan has benefits for renal involvement, the different effects depending on the gene mutation type are unknown. Thus, we explore the different effects of tolvaptan on the annual changes in total kidney volume (%TKV) and estimated glomerular filtration rate (eGFR) according to the gene mutation type in ADPKD patients. METHODS: In total, 135 ADPKD patients were screened, and 22 patients taking tolvaptan for at least a year were retrospectively studied at the Kurume University Hospital. We examined the decline in renal function and %TKV by computed tomography and analyzed the gene mutation. Patients were classified into the following four groups according to gene mutation type: PKD1-truncated, PKD1-non-truncated, PKD2, and mutation not found. Patients were treated with tolvaptan, and the effects of tolvaptan were analyzed according to the gene mutation type. RESULTS: Patients (age: 52.3 ± 11.2 years) were administered tolvaptan at a dose of 45 or 60 mg. No variation was observed in the annual changes in eGFR (%eGFR) (before: - 10.5% ± 13.9%, after: - 14.4% ± 8.1%, P = 0.139), whereas %TKV was significantly improved after the tolvaptan treatment (before: 14.9% ± 8.0%, after: - 5.4% ± 7.6%, P < 0.001). Unlike %eGFR, tolvaptan treatment significantly improved %TKV, regardless of the type of gene mutation. CONCLUSIONS: A year treatment with tolvaptan significantly improved %TKV in patients with ADPKD, regardless of the gene mutation type.

Better remission rates in elderly Japanese patients with primary membranous nephropathy in nationwide real-world practice: The Japan Nephrotic Syndrome Cohort Study (JNSCS).

BACKGROUND: The aim of the present study was to clarify the prevalence of immunosuppressive drug use and outcomes in elderly and non-elderly patients with primary membranous nephropathy (MN) in nationwide real-world practice in Japan. PATIENTS AND METHODS: Between 2009 and 2010, 374 patients with primary nephrotic syndrome were enrolled in the cohort study (The Japan Nephrotic Syndrome Cohort Study, JNSCS), including 126 adult patients with MN. Their clinical characteristics were compared with those of nephrotic patients with primary MN registered in a large nationwide registry (The Japan Renal Biopsy Registry, J-RBR). Outcomes and predictors in the elderly (≥ 65 years) and non-elderly groups were identified. RESULTS: Similar clinical characteristics were observed in JNSCS patients and J-RBR patients (n = 1808). At the early stage of 1 month, 84.1% of patients were treated with immunosuppressive therapies. No significant differences were observed in therapies between age groups. However, elderly patients achieved complete remission (CR) more frequently than non-elderly patients, particularly those treated with therapies that included corticosteroids. No significant differences were noted in serum creatinine (sCr) elevations at 50 or 100%, end-stage kidney disease, or all-cause mortality between age groups. Corticosteroids were identified as an independent predictor of CR (HR 2.749, 95%CI 1.593-4.745, p = 0.000) in the multivariate Cox's model. sCr levels, hemoglobin levels, immunosuppressants, clinical remission, and relapse after CR were independent predictors of sCr × 1.5 or × 2.0. CONCLUSION: Early immunosuppressive therapy including corticosteroids for primary MN showed better remission rates in elderly patients in a nationwide cohort study.

Uremic Toxin-Targeting as a Therapeutic Strategy for Preventing Cardiorenal Syndrome.

Chronic kidney disease (CKD) is a global health problem. CKD patients are at high risk of developing cardiovascular disease (CVD), including coronary artery disease, heart failure and stroke. Several factors invoke a vicious cycle of CKD and CVD, which is referred as to "cardiorenal syndrome". Among these factors, the compounds retained through loss of renal excretion play a pathological role in causing atherosclerosis and CVD. These compounds have been broadly classified as uremic toxins because of their accumulation with declining renal function and cytotoxicity. The major uremic toxins contributing to CVD are asymmetric dimethylarginine (ADMA), advanced glycation endproducts (AGE), and trimethyl amine N-oxide (TMAO). ADMA is linked to CVD through regulation of nitric oxide, reactive oxygen species, and renal anemia. AGE not only directly accumulates in the heart and kidney, but interacts with the receptor for AGE (RAGE), leading to cell damage in CVD. TMAO correlates with a high prevalence of CVD and promotes organ fibrosis by itself. The levels of these and other uremic toxins rise with worsening CKD, inducing multiplicative damage in the heart and kidney. Therefore, a better understanding of uremic toxins has great clinical importance for preventing cardiorenal syndrome. This review highlights the molecular mechanism by which these uremic toxins are implicated in CVD and suggests the possible mutual relationship between them.

Effectiveness of immunosuppressive therapy for nephrotic syndrome in a patient with late-onset Fabry disease: a case report and literature review.

BACKGROUND: Fabry disease (FD) is an X-linked lysosomal storage disorder caused by mutations of the GLA gene, followed by deficiency in α-galactosidase A (α-gal) activity. Nephrotic syndrome, as the renal phenotype of FD, is unusual. Here, we report the rare case of a patient with FD with nephrotic syndrome whose proteinuria disappeared by immunotherapy. CASE PRESENTATION: A 67-year-old Japanese man was admitted to our hospital because of emesis, abdominal pain, and facial edema due to nephrotic syndrome. The patient was diagnosed with focal segmental glomerulosclerosis (FSGS) by renal biopsy before being diagnosed with FD, and immunotherapy was initiated. After treatment, the kidney biopsy results showed typical glycosphingolipid accumulation in the podocytes of this patient. The white blood cell α-gal activity was very low, and genetic analysis revealed a GLA gene variant (M296I), which is known as a late-onset genetic mutation of FD. Immunotherapy (steroids and cyclosporine A) dramatically improved the massive proteinuria. Currently, he has been undergoing enzyme replacement therapy, and his proteinuria has further decreased. There is the possibility that other nephrotic syndromes, such as minimal change nephrotic syndrome or FSGS, may co-exist in this patient. CONCLUSIONS: We experienced the rare case of a FD patient whose nephrotic syndrome disappeared by immunotherapy. These findings suggest that immunosuppressive treatment may be considered if nephrotic syndrome develops, even in patients with FD.

[Role of AGEs-RAGE system in CKD-MBD.]

Abnormalities, such as hyperparathyroidism, vascular calcification, and osteoporosis, are devastating complications in patients with end-stage renal disease(ESRD). These abnormalities significantly affect the quality of life and prognosis. Therefore, controlling the abnormalities of chronic kidney disease-mineral and bone metabolism play an important role in these patients. Conventionally, calcium and phosphorus metabolism abnormalities have been mainly attributed to the development of vascular calcification, but preventing vascular calcification is still difficult even if calcium and phosphorus levels are controlled. Additionally, the mechanisms of the development and progression of vascular calcification in patients with ESRD are still unknown. Recently, advanced glycation end products(AGEs)have been known to be involved in the development and promotion of bone abnormality, such as bone embrittlement and vascular calcification. Therefore, blockade of AGEs and the receptor for AGE(RAGE)system may be a novel therapeutic strategy to improve the prognosis of patients with ESRD by inhibiting bone embrittlement and vascular calcification.

Advanced glycation end products evoke inflammatory reactions in proximal tubular cells via autocrine production of dipeptidyl peptidase-4.

We have previously shown that albuminuria and renal levels of advanced glycation end products (AGEs), receptor for AGEs (RAGE), and oxidative stress are suppressed in dipeptidyl peptidase-4 (DPP-4)-deficient diabetic rats, thus suggesting the crosstalk between AGE-RAGE axis and DPP-4 in experimental diabetic nephropathy. Therefore, we examined here the role of DPP-4 in AGE-evoked inflammatory reactions in human proximal tubular cells. Proteins were extracted from proximal tubular cells, and conditioned medium was collected, both of which were subjected to western blot analysis using anti-DPP-4 antibody. RAGE-aptamer was prepared using a systemic evolution of ligands by exponential enrichment. NF-κB p65 and monocyte chemoattractant protein-1 (MCP-1) gene expression was analyzed by reverse transcription-polymerase chain reaction. AGEs significantly increased DPP-4 expression and soluble DPP-4 production by tubular cells, the latter of which was attenuated by RAGE-aptamer or an anti-oxidant, N-acetylcysteine. AGEs or DPP-4 up-regulated NF-κB p65 or MCP-1 mRNA levels in tubular cells, which were suppressed by linagliptin, an inhibitor of DPP-4. AGEs stimulated NF-κB p65 gene expression in tubular cells isolated from control rats, but not from DPP-4-deficient rats. Our present results suggest that the AGE-RAGE-mediated oxidative stress could evoke inflammatory reactions in proximal tubular cells via autocrine production of DPP-4.

Compared effects of calcium and sodium polystyrene sulfonate on mineral and bone metabolism and volume overload in pre-dialysis patients with hyperkalemia.

BACKGROUND: Hyperkalemia is prevalent in end-stage renal disease patients, being involved in life-threatening arrhythmias. Although polystyrene sulfonate (PS) is commonly used for the treatment of hyperkalemia, direct comparison of effects between calcium and sodium PS (CPS and SPS) on mineral and bone metabolism has not yet been studied. METHODS: In a randomized and crossover design, 20 pre-dialysis patients with hyperkalemia (>5 mmol/l) received either oral CPS or SPS therapy for 4 weeks. RESULTS: After 4-week treatments, there was no significant difference of changes in serum potassium (K) from the baseline (ΔK) between the two groups. However, SPS significantly decreased serum calcium (Ca) and magnesium (Mg) and increased intact parathyroid hormone (iPTH) values, whereas CPS reduced iPTH. ΔiPTH was inversely correlated with ΔCa and ΔMg (r = -0.53 and r = -0.50, respectively). Furthermore, sodium (Na) and atrial natriuretic peptide (ANP) levels were significantly elevated in patients with SPS, but not with CPS, whereas ΔNa and ΔANP were significantly correlated with each other in all the patients. We also found that ΔNa and Δ(Na to chloride ratio) were positively correlated with ΔHCO3-. In artificial colon fluid, CPS increased Ca and decreased Na. Furthermore, SPS greatly reduced K, Mg, and NH3. CONCLUSION: Compared with SPS, CPS may be safer for the treatment of hyperkalemia in pre-dialysis patients, because it did not induce hyperparathyroidism or volume overload.

Decline in estimated glomerular filtration rate is associated with risk of end-stage renal disease in type 2 diabetes with macroalbuminuria: an observational study from JDNCS.

BACKGROUND: There is increased interest in surrogate endpoints for clinical trials of chronic kidney disease. METHODS: In this nationwide observational study of 456 patients with type 2 diabetes and clinically suspected diabetic nephropathy followed for a median of 4.2 years, we evaluated the association between estimated glomerular filtration rate (eGFR) and albuminuria at baseline or during follow-up and risk of ESRD. RESULTS: Low eGFR (<60 mL/min/1.73 m2) and macroalbuminuria at enrollment were independently associated with risk of ESRD. In patients with macroalbuminuria, both ≤-50% change and -50 to -30% change in eGFR over 1 and 2 years were predictive of ESRD. The higher cut point (≥50% decline in eGFR) was more strongly predictive but less common. Remission of macroalbuminuria to normo-/microalbuminuria at 1 and 2 years was associated with a lower incidence of ESRD than no remission; however, it was not a determinant for ESRD independently of initial eGFR and initial protein-to-creatinine ratio. CONCLUSION: These results suggest that a ≥30% decline in eGFR over 1 or 2 years adds prognostic information about risk for ESRD in patients with type 2 diabetes and macroalbuminuria, supporting the consideration of percentage decline in eGFR as a surrogate endpoint among macroalbuminuric cases in type 2 diabetes. On the other hand, our study suggests that additional analyses on the relationship between remission of macroalbuminuria and risk of ESRD are needed in type 2 diabetes.

Regional variations in immunosuppressive therapy in patients with primary nephrotic syndrome: the Japan nephrotic syndrome cohort study.

BACKGROUND: The lack of high-quality clinical evidences hindered broad consensus on optimal therapies for primary nephrotic syndromes. The aim of the present study was to compare prevalence of immunosuppressive drug use in patients with primary nephrotic syndrome across 6 regions in Japan. METHODS: Between 2009 and 2010, 380 patients with primary nephrotic syndrome in 56 hospitals were enrolled in a prospective cohort study [Japan Nephrotic Syndrome Cohort Study (JNSCS)], including 141, 151, and 38 adult patients with minimal change disease (MCD), membranous nephropathy (MN), and focal segmental glomerulosclerosis (FSGS), respectively. Their clinical characteristics were compared with those of patients registered in a large nationwide registry of kidney biopsies [Japan Renal Biopsy Registry (J-RBR)]. The regional prevalence of use of each immunosuppressive drug was assessed among adult MCD, MN, and FSGS patients who underwent immunosuppressive therapy in the JNSCS (n = 139, 127, and 34, respectively). Predictors of its use were identified using multivariable-adjusted logistic regression models. RESULTS: The clinical characteristics of JNSCS patients were comparable to those of J-RBR patients, suggesting that the JNSCS included the representatives in the J-RBR. The secondary major immunosuppressive drugs were intravenous methylprednisolone [n = 33 (24.6%), 24 (19.7%), and 9 (28.1%) in MCD, MN, and FSGS, respectively] and cyclosporine [n = 25 (18.7%), 62 (50.8%), and 16 (50.0%), respectively]. The region was identified as a significant predictor of use of intravenous methylprednisolone in MCD and MN patients. CONCLUSION: Use of intravenous methylprednisolone for MCD and MN differed geographically in Japan. Its efficacy should be further evaluated in a well-designed trial.

Asymmetric Dimethylarginine Contributes to the Impaired Response to Erythropoietin in CKD-Anemia.

Erythropoietin-resistant anemia is associated with adverse cardiovascular events in patients with ESRD, but the underlying mechanism remains unclear. Here, we evaluated the role of the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA). In 54 patients with advanced CKD, erythrocyte but not plasma ADMA levels independently associated with low hemoglobin values, although levels of both types of ADMA were elevated compared with those in healthy volunteers. Furthermore, erythrocyte ADMA level associated with the erythropoietin resistance index in patients receiving a weekly injected dose of erythropoiesis-stimulating agents standardized for hemoglobin levels and body weight, whereas it correlated with the erythropoietin demand index (plasma erythropoietin units divided by the hemoglobin value) in patients not receiving erythropoiesis-stimulating agents. Compared with sham-operated controls, wild-type mice with 5/6 subtotal nephrectomy (Nx), a remnant kidney model with advanced CKD, had decreased hemoglobin, hematocrit, and mean corpuscular volume values but increased erythrocyte and plasma ADMA and plasma erythropoietin levels. In comparison, dimethylarginine dimethlaminohydrolase-1 transgenic (DDAH-1 Tg) mice, which efficiently metabolized ADMA, had significant improvements in all of the values except those for erythropoietin after 5/6 Nx. Additionally, wild-type Nx mice, but not DDAH-1 Tg Nx mice, had reduced splenic gene expression of erythropoietin receptor and erythroferrone, which regulates iron metabolism in response to erythropoietin. This study suggests that erythrocyte ADMA accumulation contributes to impaired response to erythropoietin in predialysis patients and advanced CKD mice via suppression of erythropoietin receptor expression.

RAGE-aptamer Attenuates the Growth and Liver Metastasis of Malignant Melanoma in Nude Mice.

Epidemiological studies have suggested the link between cumulative diabetic exposure and cancer. Interaction of advanced glycation end products (AGEs) with their receptor (RAGE) may contribute to the phenomenon. We examined here the effects of DNA aptamer raised against RAGE (RAGE-aptamer) on growth and liver metastasis of G361 melanoma in nude mice. Malignant melanoma cells were intradermally injected into the upper flank region of nude mice, which received continuous administration of RAGE-aptamer (38.4 pmol/day/g body weight) or vehicle intraperitoneally by an osmotic pump up to 42 days. RAGE-aptamer significantly reduced levels of 8-hydroxy-2'-deoxy-guanosine, AGEs, RAGE, proliferating nuclear antigen, cyclin D1, vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (MCP-1), and CD31 and Mac-3, respective markers of endothelial cells and macrophages in tumors of nude mice and suppressed the proliferation and liver metastasis of malignant melanoma. Furthermore, RAGE-aptamer attenuated the AGE-induced oxidative stress generation, proliferation, and VEGF and MCP-1 gene expression in both G361 melanoma cells and endothelial cells. The present findings suggest that RAGE-aptamer could attenuate melanoma growth and liver metastasis in nude mice by suppressing the tumor angiogenesis and macrophage infiltration via inhibition of the AGE-RAGE system. RAGE-aptamer may be a novel therapeutic tool for the treatment of malignant melanoma.