Urinary Protein-to-creatinine Ratios Predict Recurrence in Pediatric and Young Adult Cases of Minimal Change Nephrotic Syndrome.

High-dose steroids are required for the treatment of minimal change nephrotic syndrome (MCNS), especially for episodes of recurrence. Predicting and avoiding recurrence can help reduce the steroid dose, but prediction is currently difficult. We herein examined whether changes in laboratory data, especially the urinary protein- to-creatinine ratio (UTP/UCr), can predict clinical recurrence. We also assessed differences in clinical features between children and young adults. We included 36 patients with MCNS; for each case, we retrospectively studied laboratory data during stable remission and pre-recurrence, with the "stable" period defined as all but the 6 weeks before recurrence, and pre-recurrence defined as the 4±2 weeks before recurrence. UTP/UCr, serum albumin, etc. were measured every 5 years during stable periods. We divided patients into cohorts by age at recurrence, < 15 years and ≥ 15 years, and compared stable and pre-recurrence values for the two groups. UTP/UCr values during stable periods tended to be higher in younger patients. UTP/UCr and serum albumin showed statistically significant changes during pre-recurrence periods, but only in those aged ≥ 15 years. Thus, clinical features of recurrence differed depending on age. Signs of recurrence can be confirmed via UTP/UCr or serum albumin several weeks before recurrence in patients ≥ 15 years.

A cross-sectional nationwide survey of congenital and infantile nephrotic syndrome in Japan.

BACKGROUND: Congenital nephrotic syndrome (CNS) and infantile nephrotic syndrome (INS) cause substantial morbidity and mortality. In Japan, there is a lack of knowledge regarding the characteristics of CNS and INS. This study aimed to clarify the characteristics of CNS and INS in Japan. METHODS: This cross-sectional nationwide survey obtained data from 44 institutions in Japan managing 92 patients with CNS or INS, by means of two survey questionnaires sent by postal mail. Patients aged < 16 years by 1 April 2015, with a diagnosis of CNS or INS, were included in this study. The primary outcome was end-stage kidney disease. RESULTS: A total of 83 patients with CNS or INS were analyzed. The most frequent disease type was non-Finnish (60.2%); 33 patients (39.8%) had Finnish type. Among those with non-Finnish-type disease, 26 had no syndrome and 24 had a syndrome, of which the most frequent was Denys-Drash syndrome (70.8%). Patients with non-Finnish-type disease with syndrome showed the earliest progression to end-stage kidney disease compared with the other two groups, whereas patients with non-Finnish-type disease without syndrome progressed more slowly compared with the other two groups. In the Finnish-type group, the disease was diagnosed the earliest; a large placenta was reported more frequently; genetic testing was more frequently performed (93.8%); mental retardation was the most frequent extra-renal symptom (21.2%); and thrombosis and infection were more frequent compared with the other groups. Patients with non-Finnish-type disease with syndrome had a higher frequency of positive extra-renal symptoms (79.2%), the most common being urogenital symptoms (54.2%). Treatment with steroids and immunosuppressants was more frequent among patients with non-Finnish-type disease without syndrome. Two patients with non-Finnish-type disease without syndrome achieved complete remission. In all groups, unilateral nephrectomy was performed more often than bilateral nephrectomy and peritoneal dialysis was the most common renal replacement therapy. CONCLUSIONS: The present epidemiological survey sheds light on the characteristics of children with CNS and INS in Japan. A high proportion of patients underwent genetic examination, and patient management was in accord with current treatment recommendations and practices. TRIAL REGISTRATION: Not applicable.

Long-term outcome of childhood-onset complicated nephrotic syndrome after a multicenter, double-blind, randomized, placebo-controlled trial of rituximab.

BACKGROUND: Although rituximab effectively prevents relapses of complicated frequently relapsing nephrotic syndrome (FRNS) and steroid-dependent nephrotic syndrome (SDNS), data of long-term outcomes and safety are limited. METHODS: Fifty-one patients (age, 3-38 years) with childhood-onset complicated FRNS or SDNS, who received rituximab in investigator-initiated multicenter prospective trials were enrolled. Rituximab was administered at 375 mg/m2 once weekly for 4 weeks, and immunosuppressive agents were discontinued according to the study protocol. We investigated relapses, re-administration of immunosuppressive agents, additional rituximab treatment, body height, renal function, and late adverse events during the observation period. RESULTS: Forty-eight patients (94%) developed relapses during the observation period (median, 59 months) and the 50% relapse-free survival was 261 days. Thirty patients (59%) developed SDNS, 44 (86%) required re-administration of immunosuppressive agents, and 22 (43%) received additional rituximab treatment. All patients who were receiving immunosuppressive agents at rituximab treatment required either immunosuppressive agents or additional rituximab treatment. On the contrary, 5 of the 13 patients without immunosuppressive agents at rituximab treatment required neither immunosuppressive agents nor additional rituximab treatment and 3 of them did not develop relapse during observation period. Growth failure due to steroid toxicity did not progress and none of the patients developed chronic renal insufficiency. None of the patients suffered from rituximab-related late adverse events. CONCLUSIONS: As most patients suffer from relapses after B-cell recovery, long-term immunosuppressive agents or additional rituximab treatment is necessary. However, some patients who can discontinue immunosuppressive agents before rituximab treatment may achieve long-term remission after rituximab treatment without immunosuppressive agents.

Rituximab for childhood-onset, complicated, frequently relapsing nephrotic syndrome or steroid-dependent nephrotic syndrome: a multicentre, double-blind, randomised, placebo-controlled trial.

BACKGROUND: Rituximab could be an effective treatment for childhood-onset, complicated, frequently relapsing nephrotic syndrome (FRNS) and steroid-dependent nephrotic syndrome (SDNS). We investigated the efficacy and safety of rituximab in patients with high disease activity. METHODS: We did a multicentre, double-blind, randomised, placebo-controlled trial at nine centres in Japan. We screened patients aged 2 years or older experiencing a relapse of FRNS or SDNS, which had originally been diagnosed as nephrotic syndrome when aged 1-18 years. Patients with complicated FRNS or SDNS who met all other criteria were eligible for inclusion after remission of the relapse at screening. We used a computer-generated sequence to randomly assign patients (1:1) to receive rituximab (375 mg/m(2)) or placebo once weekly for 4 weeks, with age, institution, treatment history, and the intervals between the previous three relapses as adjustment factors. Patients, guardians, caregivers, physicians, and individuals assessing outcomes were masked to assignments. All patients received standard steroid treatment for the relapse at screening and stopped taking immunosuppressive agents by 169 days after randomisation. Patients were followed up for 1 year. The primary endpoint was the relapse-free period. Safety endpoints were frequency and severity of adverse events. Patients who received their assigned intervention were included in analyses. This trial is registered with the University Hospital Medical Information Network clinical trials registry, number UMIN000001405. FINDINGS: Patients were centrally registered between Nov 13, 2008, and May 19, 2010. Of 52 patients who underwent randomisation, 48 received the assigned intervention (24 were given rituximab and 24 placebo). The median relapse-free period was significantly longer in the rituximab group (267 days, 95% CI 223-374) than in the placebo group (101 days, 70-155; hazard ratio: 0·27, 0·14-0·53; p<0·0001). Ten patients (42%) in the rituximab group and six (25%) in the placebo group had at least one serious adverse event (p=0·36). INTERPRETATION: Rituximab is an effective and safe treatment for childhood-onset, complicated FRNS and SDNS. FUNDING: Japanese Ministry of Health, Labour and Welfare.

Functional analysis of NPHS1 mutations in Japanese patients.

BACKGROUND: Many mutations in the NPHS1 gene were detected among patients with congenital nephrotic syndrome. Functional analysis of those mutations was done with a stable-expression cell line. Nevertheless, establishing such a cell line is time-consuming. METHODS AND RESULTS: We established an easier method using automatic counting software for functional analysis with transient-transfection cells rather than a stable-expression cell line. We demonstrated maltrafficking to the plasma membrane of abnormal nephrin for immunostaining on transient-expression cells by comparison without Triton X (detecting proteins on the cell membrane only) and with Triton X (detecting proteins both on the cell membrane and inside the cell cytoplasm). We obtained relevant results with data obtained previously using a stable-expression cell line. Furthermore, we conducted functional analysis of NPHS1 mutations in Japanese patients with congenital nephrotic syndrome using this simple method, which revealed that all pathogenic mutations impaired trafficking to the protein plasma membrane. CONCLUSIONS: Functional analysis using transient-expression cells with automatic counting software was useful to demonstrate maltrafficking to the plasma membrane of a protein. All pathogenic mutations detected in Japanese patients impaired trafficking to the protein plasma membrane.

Fibroblast growth factor 23 concentrations in healthy term infants during the early postpartum period.

Fibroblast growth factor 23 (FGF23) is a potent regulator of Pi and 1,25-(OH)(2)D homeostasis. Early postpartum infants show intriguing changes in serum levels of Ca, Pi, PTH and 1,25-(OH)(2)D. However, the role of FGF23 in the early neonatal mineral metabolism has not been clarified. In order to evaluate the significance of FGF23 during the early postpartum period, we examined the circulating FGF23 levels using an intact FGF23 ELISA and a C-terminal FGF23 ELISA either in 22 umbilical cord blood samples (the cord blood) or in 22 term infants at 5 days of life (the 5-day-old infant). We also compared these ranges with those of 11 healthy adults. Data were expressed as mean+/-SD, and analyzed by two-way ANOVA, followed by the Tukey's test. C-terminal FGF23 in the cord blood, the 5-day-old infants and the healthy adults were 73.3+/-22.4, 81.0+/-28.2 and 39.0+/-7.8 RU/ml, respectively. Intact FGF23 in the cord blood, the 5-day-old infants and the healthy adults were 3.9+/-1.6, 21.8+/-17.6, and 27.6+/-7.3 pg/ml, respectively. Immunoprecipitation assays using anti-FGF23 antibodies demonstrated that the intact 32 kDa FGF23 was low and the fragmented FGF23 of 18 kDa was abundant in the cord blood compared with those in the healthy adults. In conclusion, our observations indicated that the intact FGF23/C-terminal FGF23 ratio was very low due to the fragmentation of FGF23 during the early postpartum period and might have a considerable contribution to the Pi homeostasis in the healthy term infants.

Fibroblast growth factor 23 concentrations in healthy term infants during the early postpartum period.

Fibroblast growth factor 23 (FGF23) is a potent regulator of Pi and 1,25-(OH)(2)D homeostasis. Early postpartum infants show intriguing changes in serum levels of Ca, Pi, PTH and 1,25-(OH)(2)D. However, the role of FGF23 in the early neonatal mineral metabolism has not been clarified. In order to evaluate the significance of FGF23 during the early postpartum period, we examined the circulating FGF23 levels using an intact FGF23 ELISA and a C-terminal FGF23 ELISA either in 22 umbilical cord blood samples (the cord blood) or in 22 term infants at 5days of life (the 5-day-old infant). We also compared these ranges with those of 11 healthy adults. Data were expressed as mean+/-SD, and analyzed by two-way ANOVA, followed by the Tukey's test. C-terminal FGF23 in the cord blood, the 5-day-old infants and the healthy adults were 73.3+/-22.4, 81.0+/-28.2 and 39.0+/-7.8 RU/ml, respectively. Intact FGF23 in the cord blood, the 5-day-old infants and the healthy adults were 3.9+/-1.6, 21.8+/-17.6, and 27.6+/-7.3 pg/ml, respectively. Immunoprecipitation assays using anti-FGF23 antibodies demonstrated that the intact 32 kDa FGF23 was low and the fragmented FGF23 of 18kDa was abundant in the cord blood compared with those in the healthy adults. In conclusion, our observations indicated that the intact FGF23/C-terminal FGF23 ratio was very low due to the fragmentation of FGF23 during the early postpartum period and might have a considerable contribution to the Pi homeostasis in the healthy term infants.

NPHS1 gene mutation in Japanese patients with congenital nephrotic syndrome.

BACKGROUND AND METHODS: The NPHS1gene was analysed in different five Japanese patients with congenital nephrotic syndrome (CNS) from the patients in a previous report (Sako M, Nakanishi K, Obana M et al. Analysis of NPHS1, NPHS2, ACTN4, and WT1 in Japanese patients with congenital nephrotic syndrome. Kidney Int 2005; 67: 1248-1255) that suggested that the mutation of NPHS1 was not a major cause of CNS in Japanese patients. Genomic DNA was extracted from leukocytes, and all exons and exon-intron boundaries were analysed for NPHS1 using polymerase chain reaction and direct sequencing. RESULTS AND CONCLUSIONS: Compound heterozygous mutations of NPHS1 were found in four patients and homozygous mutations in one patient. Interestingly, three patients out of five had the same mutation in NPHS1: nt2515(delC). Parents who had this mutation heterozygously were from neighbouring prefectures. Two among five patients in this research and one in the previous report (Kidney Int 2005; 67:1248-1255) had the same mutation: 736G > T in exon 7. All mutations including these two mutations except for one have never been reported outside of Japan yet.

Late-onset Lymphedema and Protein-losing Enteropathy with Noonan Syndrome.

Noonan syndrome is characterized by facial dysmorphology, congenital heart disease and growth failure. Although it is also accompanied by deranged lymph-vessel formation, protein-losing enteropathy (PLE) with Noonan syndrome is rarely reported. We report clinical information about a boy with Noonan syndrome and late-onset lymphedema and PLE after standing for long periods of time during athletic practice sessions. The boy recovered from lymphedema and PLE after administration of 2.5 g of albumin followed by resting and raising his legs. They did not recur after he began walking again. Standing for long periods of time congested the lymph stream at the abdominal lymph vessel, whose formation is frequently disturbed in Noonan syndrome, and the increased pressure caused lymphedema and PLE. PLE is one of the clinical manifestations of Noonan syndrome.

NF-(kappa)B-inducing kinase controls lymphocyte and osteoclast activities in inflammatory arthritis.

NF-(kappa)B is an important component of both autoimmunity and bone destruction in RA. NF-(kappa)B-inducing kinase (NIK) is a key mediator of the alternative arm of the NF-(kappa)B pathway, which is characterized by the nuclear translocation of RelB/p52 complexes. Mice lacking functional NIK have no peripheral lymph nodes, defective B and T cells, and impaired receptor activator of NF-kappaB ligand-stimulated osteoclastogenesis. We investigated the role of NIK in murine models of inflammatory arthritis using Nik-/- mice. The serum transfer arthritis model is initiated by preformed antibodies and required only intact neutrophil and complement systems in recipients. While Nik-/- mice had inflammation equivalent to that of Nik+/+ controls, they showed significantly less periarticular osteoclastogenesis and less bone erosion. In contrast, Nik-/- mice were completely resistant to antigen-induced arthritis (AIA), which requires intact antigen presentation and lymphocyte function but not lymph nodes. Additionally, transfer of Nik+/+ splenocytes or T cells to Rag2-/- mice conferred susceptibility to AIA, while transfer of Nik-/- cells did not. Nik-/- mice were also resistant to a genetic, spontaneous form of arthritis, generated in mice expressing both the KRN T cell receptor and H-2. Thus, NIK is important in the immune and bone-destructive components of inflammatory arthritis and represents a possible therapeutic target for these diseases.

Marrow stromal cells and osteoclast precursors differentially contribute to TNF-alpha-induced osteoclastogenesis in vivo.

The marrow stromal cell is the principal source of the key osteoclastogenic cytokine receptor activator of NF-kappaB (RANK) ligand (RANKL). To individualize the role of marrow stromal cells in varying states of TNF-alpha-driven osteoclast formation in vivo, we generated chimeric mice in which wild-type (WT) marrow, immunodepleted of T cells and stromal cells, is transplanted into lethally irradiated mice deleted of both the p55 and p75 TNFR. As control, similarly treated WT marrow was transplanted into WT mice. Each group was administered increasing doses of TNF-alpha. Exposure to high-dose cytokine ex vivo induces exuberant osteoclastogenesis irrespective of in vivo TNF-alpha treatment or whether the recipient animals possess TNF-alpha-responsive stromal cells. In contrast, the osteoclastogenic capacity of marrow treated with lower-dose TNF-alpha requires priming by TNFR-bearing stromal cells in vivo. Importantly, the osteoclastogenic contribution of cytokine responsive stromal cells in vivo diminishes as the dose of TNF-alpha increases. In keeping with this conclusion, mice with severe inflammatory arthritis develop profound osteoclastogenesis and bone erosion independent of stromal cell expression of TNFR. The direct induction of osteoclast recruitment by TNF-alpha is characterized by enhanced RANK expression and sensitization of precursor cells to RANKL. Thus, osteolysis attending relatively modest elevations in ambient TNF-alpha depends upon responsive stromal cells. Alternatively, in states of severe periarticular inflammation, TNF-alpha may fully exert its bone erosive effects by directly promoting the differentiation of osteoclast precursors independent of cytokine-responsive stromal cells and T lymphocytes.

A missense mutation in the nephrin gene impairs membrane targeting.

BACKGROUND: NPHS1, which encodes nephrin, recently has been identified as the gene in which mutations cause congenital nephrotic syndrome of the Finnish type (CNF). We previously reported novel missense mutations of NPHS1 in a Japanese patient with CNF. However, the mechanism by which these missense mutations cause the disorder remains to be clarified. METHODS: Wild-type nephrin and mutated nephrin complementary DNA were each tagged by the green fluorescence protein (GFP) gene; the expressing vectors of the fusion protein were each transfected to human embryonic kidney 293 cells. We compared intracellular localization of mutated nephrin with that of wild-type nephrin by using GFP and immunostaining examination. RESULTS: In both wild-type and mutated nephrin (Glu(447)Lys), GFP and immunostaining resulted in a colocalized microgranular pattern along the cell membrane that indicated these recombinant proteins were located at the cell surface. Conversely, in mutated nephrin (Asp(819)Val), GFP aggregation was observed in the cytoplasm, and no fluorescence was observed at the cell membrane, indicating that recombinant mutated nephrin (Asp(819)Val) could not be distributed at the cell membrane and instead was retained in cytoplasm. CONCLUSION: We confirmed that the missense mutation GAC-to-GTC transversion leading to an Asp(819)Val caused the disorder. The present study analyzes in vitro distribution of nephrin with a missense point mutation. The analysis uses a new convenient method, construction of a nephrin-GFP fusion protein.