X-linked Alport syndrome associated with a synonymous p.Gly292Gly mutation alters the splicing donor site of the type IV collagen alpha chain 5 gene.

BACKGROUND: X-linked Alport syndrome (XLAS) is a progressive hereditary nephropathy caused by mutations in the type IV collagen alpha chain 5 gene (COL4A5). Although many COL4A5 mutations have previously been identified, pathogenic synonymous mutations have not yet been described. METHODS: A family with XLAS underwent mutational analyses of COL4A5 by PCR and direct sequencing, as well as transcript analysis of potential splice site mutations. In silico analysis was also conducted to predict the disruption of splicing factor binding sites. Immunohistochemistry (IHC) of kidney biopsies was used to detect α2 and α5 chain expression. RESULTS: We identified a hemizygous point mutation, c.876A>T, in exon 15 of COL4A5 in the proband and his brother, which is predicted to result in a synonymous amino acid change, p.(Gly292Gly). Transcript analysis showed that this mutation potentially altered splicing because it disrupted the splicing factor binding site. The kidney biopsy of the proband showed lamellation of the glomerular basement membrane (GBM), while IHC revealed negative α5(IV) staining in the GBM and Bowman's capsule, which is typical of XLAS. CONCLUSIONS: This is the first report of a synonymous COL4A5 substitution being responsible for XLAS. Our findings suggest that transcript analysis should be conducted for the future correct assessment of silent mutations.

Serum hepcidin levels and reticulocyte hemoglobin concentrations as indicators of the iron status of peritoneal dialysis patients.

Hepcidin is the key mediator of renal anemia, and reliable measurement of serum hepcidin levels has been made possible by the ProteinChip system. We therefore investigated the iron status and serum hepcidin levels of peritoneal dialysis (PD) patients who had not received frequent doses of an erythrocytosis-stimulating agent (ESA) and had not received iron therapy. In addition to the usual iron parameters, the iron status of erythrocytes can be determined by measuring reticulocyte hemoglobin (RET-He). The mean serum hepcidin level of the PD patients (n = 52) was 80.7 ng/mL. Their serum hepcidin levels were significantly positively correlated with their serum ferritin levels and transferrin saturation (TSAT) levels, but no correlations were found between their serum hepcidin levels and RET-He levels, thereby suggesting that hepcidin has no effect on the iron dynamics of reticulocytes. Since low serum levels of CRP and IL-6, biomarkers of inflammation, were not correlated with the serum hepcidin levels, there is likely to be a threshold for induction of hepcidin expression by inflammation.

[Clinical usefulness of reticulocyte hemoglobin equivalent (RET-He) in patients at the pre-dialysis stage and in patients on peritoneal dialysis].

BACKGROUND: Evaluation of the iron status of patients with renal anemia provides information essential to prescribing adequate rHuEPO therapy. Cellular iron status can be determined by the recently available method of measuring the reticulocyte hemoglobin equivalent (RET-He). We previously showed that RET-He values were correlated with conventional parameters and with a direct marker of the reticulocyte hemoglobin (CHr) content of hemodialysis patients. We attempted to utilize the measurements of RET-He levels of non-dialyzed patients and the iron status of peritoneal dialysis (PD) patients. METHODS: Iron deficiency was defined on the basis of the TSAT (< 20 %) and ferritin (< 100 ng/mL) levels. RET-He levels and conventional red blood cell parameters were measured with a Sysmex XE-2100 automated blood cell counter. CHr was measured with an ADVIA120 autoanalyzer. The serum hepcidin levels of PD patients were measured by mass-spectrometry. RESULTS: The mean RET-He value was 32.0 pg in the non-dialysis group and 32.5 pg in the PD group, and a correlation was found between the RET-He and TSAT values, but not the ferritin values in both groups. The serum hepcidin level was 49.8 pg in the PD group and there was a positive correlation between their hepcidin and ferritin values. Receiver operating characteristic analysis yielded a cut-off value of RET-He in the non-dialysis group (31.0 pg) and the PD group (32.7 pg). The RET-He values of PD patients who were switched from epoetin beta to darbepoetin alfa responded more rapidly than TSAT or ferritin values. CONCLUSION: RET-He is a new parameter, whose values are equivalent to CHr, and can be easily measured with a widely available and popular blood cell counter. Reticulocyte hemoglobin is an indispensable marker of iron status for chronic kidney disease patients. Moreover, reticulocyte hemoglobin is likely to provide useful information regarding the need for iron supplementation in patients being treated with an ESA.

[Clinico-pathological features and outcome in adult patients with Henoch-Schönlein purpura nephritis].

We examined the data of 24 patients with Henoch-Schönlein purpura nephritis (HSPN) over a 5-year follow-up period. Proteinuria, sediment RBC and CRP significantly decreased between the time of diagnosis and the end of the 5-year period. In the steroid usage group (n = 16), proteinuria was significantly higher, and crescent formation was significant higher at the time of diagnosis than in the non-steroid usage group (n = 8). However, there was no significant difference in the decrease in eGFR from the baseline at the end of the 5-year period between the two groups. Furthermore, to clarify the factors influencing the risk of renal function deterioration, we divided the patients into two groups, the (delta eGFR/pre eGFR) <0.25 group (n = 13) and (delta eGFR/pre eGFR) >0.25 group (n = 11), and compared the clinico-pathophysiological characteristics between the two groups. In the (delta eGFR/pre eGFR) >0.25 group, the ratio of glomerular obsolescence at the time of diagnosis was significantly higher than in the (delta eGFR/pre eGFR) <0.25 group. Glomerular obsolescence was identified as an independent risk factor for renal function deterioration. In this study, the prognosis of HSPN was related to glomerular obsolescence rather than to the disease activity. It may be necessary to consider the decrease in nephrons, in accordance with non-immunological glomerular obsolescence, in addition to immunological treatment to clarify the prognosis.

Combined cyclosporine and prednisolone therapy in adult patients with the first relapse of minimal-change nephrotic syndrome.

BACKGROUND: Although minimal-change nephrotic syndrome (MCNS) is highly steroid-responsive, some patients show frequent relapses, necessitating administration of repeated courses of prednisolone (PSL) at high doses. The adverse effects of long-term PSL treatment include osteoporosis, infection, diabetes, cataract, etc., most of which are serious. It is therefore necessary to establish useful strategies to reduce the PSL dose. METHODS: Patients with the first relapse of MCNS were randomly assigned to two groups, namely, the CyA (AUC 1700-2000 ng/ml) + PSL (0.8 mg/kg/day) group (n = 26) and the PSL alone (PSL) (1.0 mg/kg/day) group (n = 26), and the clinical characteristics were compared between the two groups. All patients used C2 for CyA monitoring. RESULTS: A significant decrease of the urinary protein excretion (P = 0.02) and serum total cholesterol (P = 0.003) was observed at 2 weeks from the first relapse in the CyA + PSL group. The increase in the serum total protein (P = 0.03) and serum albumin (P = 0.007) as compared with that in the PSL group was also observed in the CyA + PSL group at this time-point. The time to remission in the CyA + PSL group was shorter than that in the PSL group (P = 0.006). CONCLUSION: It was possible to obtain early remission and reduce the PSL dose with combined CyA and PSL therapy in patients with MCNS.

Monitoring of blood cyclosporine concentration in steroid-resistant nephrotic syndrome.

OBJECTIVE: Cyclosporine has been used for patients with nephrotic syndrome. Because of substantial inter- and intra-patient variability and a narrow therapeutic window, drug monitoring of cyclosporine is mandatory. To confirm the therapeutic effects of a cyclosporine microemulsion (CSAME), the absorption profile of the agent after preprandial administration was determined in steroid-resistant patients with refractory nephrotic syndrome. METHODS: Fourteen patients were enrolled into the study (mean age, 31.2+/-12; 6 men, 8 women). The patients received 1.5 mg/kg of cyclosporine 30 minutes before breakfast for 6 months. Blood cyclosporine concentration was measured 5 times serially: before administration (C0) and at 1-hour intervals until 4 hours after administration of cyclosporine (C1-C4). In addition, area under the concentration-time curve from 0-4 hours (AUC0-4) was calculated. RESULTS: After 6 months, CSAME showed marked improvement in proteinuria levels (8.3+/-4.8 g/day vs 0.8+/-0.4 g/day, p<0.001). No changes in serum creatinine and urea nitrogen levels were observed. In 83% of the patients, the CSAME peak concentration appeared within 1 hour after administration (C1). A strong positive correlation was noted between AUC0-4 and C1 (R2=0.90312) and C2 (R2=0.78431). The mean steroid (prednisolone) dose was 40 mg/day when CSAME treatment was started, but a lowering of the dose to 17.5 mg/day (p<0.001) was achieved at 6 months after CSAME therapy. CONCLUSION: Preprandial administration of CSAME is effective in steroid-resistant patients with refractory nephrotic syndrome. C1 or C2, but not C0, was a good clinical marker for CSAME exposure.

[Effects of steroid therapy on membranous nephropathy].

BACKGROUND: Although membranous nephropathy is a common cause of nephrotic syndrome in adults, its treatment remains under debate. METHODS: To clarify the effects of steroid therapy, the data of 51 Japanese adult patients with idiopathic membranous nephropathy who received treatment at our department were analyzed retrospectively. We divided the patients with nephrotic syndrome and a serum creatinine level <1.7 mg/dL, into two groups: the steroid therapy group (n=20) and the non-steroid therapy group (n=7), and compared the clinical characteristics between the two groups. RESULTS: Significantly decreased proteinuria levels (p<0.05) after 2 and 5 years were observed in the steroid therapy group as compared to the non-steroid therapy group. There was no significant difference in the serum creatinine levels after 2 and 5 years between the steroid therapy group and the non-steroid therapy group. CONCLUSION: Steroid therapy in idiopathic membranous nephropathy showed good efficacy in patients with nephrotic syndrome.

Patterns in the prevalence of hepatitis C virus infection at the start of hemodialysis in Japan.

BACKGROUND: Although hepatitis C virus (HCV) infection is a persistent public health concern in hemodialysis patients, there seem to have been only a few reports on the prevalence of HCV at the start of hemodialysis. In this study we investigated whether patients starting on hemodialysis therapy are positive for anti-HCV antibody or not. METHODS: The 400 patients who began regular hemodialysis between February 2003 and June 2007 were enrolled in this study. Clinical data such as age, anti-HCV antibody and primary cause of end-stage kidney disease (ESKD) were examined. As healthy controls we used 70,717 healthy blood donors in 2005 whose data were obtained from Tokyo Metropolitan Red Cross Blood Center. Anti-HCV antibody was used as an indicator of HCV infection. Since the prevalence of HCV infection is affected by age in Japan, we classified the patients by age group. RESULTS: The anti-HCV antibody prevalence rate among the patients who were new to hemodialysis was 7.3%, as opposed to 0.15% in the healthy volunteers. The prevalence of HCV in the 31-45-, 46-60-, and 61-year-old groups was significantly higher among the hemodialysis patients than among the healthy volunteers (P = 0.0209, <0.0001, and <0.0001, respectively). The prevalence rate of anti-HCV antibody was higher among men (10.0%) than among women (1.5%, P < 0.0001) in the hemodialysis patients. The anti-HCV-antibody-positive patients were significantly older than the anti-HCV-antibody-negative patients (66.4 +/- 14.3 years versus 58.6+/-16.6 years; P = 0.0152). Diabetic nephropathy was a more frequent cause of ESKD among the anti-HCV-antibody-positive patients (30.4%) than among the anti-HCV-antibody-negative patients (19.9%, P = 0.0122). Among the anti-HCV-antibody-positive patients, 55.2% had received a blood transfusion. The rate was significantly higher than that among the anti-HCV-antibody-negative patients (19.4%, P < 0.0001). CONCLUSION: The results showed a much higher rate of anti-HCV antibody positivity in patients new to hemodialysis than in healthy volunteers. Older age, blood transfusion, male gender, and diabetic nephropathy seemed to be risk factors for anti-HCV antibody positivity in Japan.

[Case of membranous nephropathy associated with argyria].

We experienced a case of membranous nephropathy associated with argyria. The patient was a 78-year-old woman who had noticed blue skin of the face and azure lunulae for 8 years. She was admitted to our hospital for edema and proteinuria. She was diagnosed as membranous nephropathy by needle renal biopsy, and treated with prednisolone. Her proteinuria disappeared after 63 days. We investigated the blue skin of her face and azure lunulae. Skin biopsy was performed and black granules deposited in the upper layer of the corium were observed. The granules were identified with silver by EDS (energy-dispersive X-ray spectroscopy) analysis. Membranous nephropathy associated with gold or mercury has been reported, but association with silver has not been reported. We considered that this is a rare case of membranous nephropathy associated with silver.