Pediatric frequent relapsing nephrotic syndrome with multiple cerebral infarctions accompanied by patent foramen ovale and cerebral venous sinus thrombosis: a case report.

BACKGROUND: Idiopathic nephrotic syndrome (NS) presents as a hypercoagulable state, of which thromboembolism (TE) is a well-known life-threatening complication. Although TE is more likely to occur in venous vessels than arterial vessels, arterial TE is important because it may cause after-effects, including tissue necrosis and cerebral infarction (CI); therefore, prompt diagnosis and appropriate treatment are required. We report a pediatric NS case with multiple CIs. CASE PRESENTATION: A 14-year-7-month-old Japanese girl was diagnosed with frequent relapsing NS, accompanied by headache and disturbance of consciousness during the second relapse. Brain magnetic resonance imaging (MRI) and four-dimensional computed tomography revealed multiple CIs, vasogenic edema, and cerebral venous sinus thrombosis (CVST). The patient had no underlying thrombophilia other than hypercoagulability due to NS and prednisolone (PSL), and no cardiac arrhythmia; however, a right-to-left shunt through the patent foramen ovale (PFO) was observed with the Valsalva maneuver by echocardiography. Therefore, we assumed that a potential cause of multiple CIs might be an embolic stroke, caused by thrombosis formed from a hypercoagulable state due to NS and PSL treatment and reached through PFO. Antiplatelet and anticoagulant therapies were administered for TE. She was treated with PSL and mycophenolate mofetil (MMF) for NS. Rituximab (RTX) was administered to prevent NS relapse after complete remission (CR). She underwent transcatheter PFO closure at age 14 years and 9 months because we considered that the right-to-left shunt through the PFO would be one of the risks for recurrent cerebral embolism when NS relapses. One year after the onset of CIs, an MRI indicated that the CVST had resolved, leaving no neurological sequelae due to CI; therefore, anticoagulant therapy was discontinued. And then she has been in CR for NS with only MMF therapy. CONCLUSIONS: CI is a serious complication in patients with NS. The pathogenesis of multiple CIs is various, including right-to-left shunt through PFO, in addition to the hypercoagulability due to NS. It is important to investigate and manage underlying risks such as PFO, besides preventing the relapses of NS by aggressive treatments using MMF and RTX, in patients with NS.

Hepatic veno-occlusive disease accompanied by thrombotic microangiopathy developed during treatment of juvenile dermatomyositis and macrophage activation syndrome: A case report.

Hepatic veno-occlusive disease (VOD) is a complication of haematopoietic stem cell transplantation. VOD is associated with the occurrence of thrombotic microangiopathy (TMA). In haematopoietic stem cell transplantation, VOD and TMA are endothelial syndromes resulting from endothelial cell activation and dysfunction. In rheumatic disease, while TMA is not rare, there are few reports of VOD. In idiopathic myositis, only one case with VOD and TMA complications has been reported, and there are no published cases in juvenile dermatomyositis (JDM). We report a case of JDM manifesting VOD and TMA complications during the treatment for myositis and macrophage activation syndrome (MAS). A 5-year-old boy diagnosed as anti-nuclear matrix protein 2 antibody-positive JDM was complicated by MAS. He received pulsed methylprednisolone, prednisolone, and tacrolimus, but JDM and MAS progressed. He was then treated with intravenous cyclophosphamide and cyclosporine A, with improvement in myositis symptoms and MAS. After initiation of cyclophosphamide and cyclosporine A, he developed haemolysis, painful hepatomegaly, liver damage, and ascites. He was diagnosed with VOD and TMA. Cyclophosphamide and cyclosporine A were discontinued, with recovery from VOD and TMA. The patient remained well on treatment with methotrexate, without any relapse of JDM and MAS to date. The presence of vasculopathy and hypercytokinaemia because of JDM and MAS exacerbated endothelial cell damage. In the present case, we suggest that the main cause of VOD was medication with CY and CsA, which had been used to treat acute exacerbation of MAS and JDM.

USP40 deubiquitinates HINT1 and stabilizes p53 in podocyte damage.

Podocyte damage is a major pathological lesion leading to focal segmental glomerulosclerosis (FSGS). Podocytes damaged by cellular stress undergo hypertrophy to compensate for podocytopenia. It is known that cyclin-dependent kinase inhibitors induced by p53 ensure podocytes hypertrophy; however, its precise mechanism remains to be further investigated. In this study, we found that ubiquitin specific protease 40 (USP40) is a novel regulator of p53. Although USP40 knockout mice established in the present study revealed no abnormal kidney phenotype, intermediate filament Nestin was upregulated in the glomeruli, and was bound to and colocalized with USP40. We also found that USP40 deubiquitinated histidine triad nucleotide-binding protein 1 (HINT1), an inducer of p53. Gene knockdown experiments of USP40 in cultured podocytes revealed the reduction of HINT1 and p53 protein expression. Finally, in glomerular podocytes of mouse FSGS, upregulation of HINT1 occurred in advance of the proteinuria, which was followed by upregulation of USP40, p53 and Nestin. In conclusion, USP40 bound to Nestin deubiquitinates HINT1, and in consequence upregulates p53. These results provide additional insight into the pathological mechanism of podocyte hypertrophy in FSGS.

Mycophenolate Mofetil after Rituximab for Childhood-Onset Complicated Frequently-Relapsing or Steroid-Dependent Nephrotic Syndrome.

BACKGROUND: Rituximab is the standard therapy for childhood-onset complicated frequently relapsing or steroid-dependent nephrotic syndrome (FRNS/SDNS). However, most patients redevelop FRNS/SDNS after peripheral B cell recovery. METHODS: We conducted a multicenter, randomized, double-blind, placebo-controlled trial to examine whether mycophenolate mofetil (MMF) administration after rituximab can prevent treatment failure (FRNS, SDNS, steroid resistance, or use of immunosuppressive agents or rituximab). In total, 39 patients (per group) were treated with rituximab, followed by either MMF or placebo until day 505 (treatment period). The primary outcome was time to treatment failure (TTF) throughout the treatment and follow-up periods (until day 505 for the last enrolled patient). RESULTS: TTFs were clinically but not statistically significantly longer among patients given MMF after rituximab than among patients receiving rituximab monotherapy (median, 784.0 versus 472.5 days, hazard ratio [HR], 0.59; 95% confidence interval [95% CI], 0.34 to 1.05, log-rank test: P=0.07). Because most patients in the MMF group presented with treatment failure after MMF discontinuation, we performed a post-hoc analysis limited to the treatment period and found that MMF after rituximab prolonged the TTF and decreased the risk of treatment failure by 80% (HR, 0.20; 95% CI, 0.08 to 0.50). Moreover, MMF after rituximab reduced the relapse rate and daily steroid dose during the treatment period by 74% and 57%, respectively. The frequency and severity of adverse events were similar in both groups. CONCLUSIONS: Administration of MMF after rituximab may sufficiently prevent the development of treatment failure and is well tolerated, although the relapse-preventing effect disappears after MMF discontinuation.

Clinical practice guidance for childhood-onset systemic lupus erythematosus-secondary publication.

Childhood-onset systemic lupus erythematosus (cSLE) has been recognised as a more acute and severe autoimmune disease than adult-onset SLE. With the development of medications for the disease and supportive therapy, the mortality rate associated with cSLE has drastically improved; the 10-year survival rate among patients with cSLE between 1995 and 2006 in Japan was 98.3%. However, the 10-year survival rate without any permanent functional impairment remained low at 66.1%. Therefore, the current treatment goal for cSLE is to ensure that they can perform normal daily activities throughout their lives by preventing the occurrence and/or progression of organ damage. For this purpose, appropriate treatments and evaluations are required according to the severity and risk of organ damage; however, there are no established guidelines for cSLE. Therefore, the Pediatric Rheumatology Association of Japan and the Pediatric Rheumatology Subcommittee in the Japan College of Rheumatology developed a comprehensive guidance for clinical practice based on cSLE-related data collected from Japanese national surveys and relevant articles from both domestic and international sources. However, due to the lack of indications for defined and objective evidence quality levels, this guidance should be used on the basis of the judgement of the attending physicians for individual patients.

Systematic Review of Genotype-Phenotype Correlations in Frasier Syndrome.

INTRODUCTION: Frasier syndrome (FS) is a rare inherited kidney disease caused by intron 9 splicing variants of WT1. For wild-type WT1, 2 active splice donor sites in intron 9 cause a mixture of 2 essential transcripts (with or without lysine-threonine-serine [+/KTS or -KTS]), and imbalance of the +KTS/-KTS ratio results in the development of FS. To date, 6 causative intron 9 variants have been identified; however, detailed transcript analysis has not yet been conducted and the genotype-phenotype correlation also remains to be elucidated. METHODS: We conducted an in vitro minigene splicing assay for 6 reported causative variants and in vivo RNA sequencing to determine the +KTS/-KTS ratio using patients' samples. We also performed a systematic review of reported FS cases with a description of the renal phenotype. RESULTS: The in vitro assay revealed that although all mutant alleles produced -KTS transcripts only, the wild-type allele produced both +KTS and -KTS transcripts at a 1:1 ratio. In vivo RNA sequencing showed that patients' samples with all heterozygous variants produced similar ratios of +KTS to -KTS (1:3.2-1:3.5) and wild-type kidney showed almost a 1:1 ratio (1:0.85). A systematic review of 126 cases clarified that the median age of developing ESKD was 16 years in all FS patients, and there were no statistically significant differences between the genotypes or sex chromosome karyotypes in terms of the renal survival period. CONCLUSION: Our study suggested no differences in splicing pattern or renal survival period among reported intron 9 variants causative of FS.

Pediatric Dual-Energy X-Ray Absorptiometry in Japan: A Proposal for Shared Access to Equipment.

BACKGROUND: Regular assessment of bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) is essential for detecting glucocorticoid-induced osteoporosis in juvenile-onset autoimmune diseases. Z-score is used to standardize osteoporosis assessment in children and is evaluated with only one of three devices in Japan. The purpose of this study was to determine how many Japanese medical facilities for pediatric rheumatic diseases were unable to use Z-scores to evaluate osteoporosis. METHODS: Electronic questionnaires were distributed between 2017 and 2019 to hospitals belonging to the Pediatric Rheumatology Association of Japan and to university hospitals and public children's hospitals that provide medical care for pediatric rheumatic diseases. The questionnaire inquired about the location of DXA measurement, manufacturer (Hologic, GE healthcare, Hitachi), and measurement site, and the answers were collected using Google Forms. Statcel 4 was used for analysis. RESULTS: Overall, 120 facilities responded to the survey, of which 117 had DXA. In the remaining three facilities, DXA was not installed in two and was out of order in one. Bone loss in childhood was evaluated using a Z-score calculated from age-based reference values; however, 30% of hospitals without HOLOGIC DXA could not evaluate osteoporosis by Z-score in Japanese childhood. The characteristics of the hospitals enrolled in this study did not bias the selection of Hologic DXA. CONCLUSIONS: Neighboring institutions should consider sharing access to Hologic DXA equipment, to ensure use of uniform reference values. GE BMD reference values should be established for Japanese children.

Exploitation of Elevated Extracellular ATP to Specifically Direct Antibody to Tumor Microenvironment.

The extracellular adenosine triphosphate (ATP) concentration is highly elevated in the tumor microenvironment (TME) and remains tightly regulated in normal tissues. Using phage display technology, we establish a method to identify an antibody that can bind to an antigen only in the presence of ATP. Crystallography analysis reveals that ATP bound in between the antibody-antigen interface serves as a switch for antigen binding. In a transgenic mouse model overexpressing the antigen systemically, the ATP switch antibody binds to the antigen in tumors with minimal binding in normal tissues and plasma and inhibits tumor growth. Thus, we demonstrate that elevated extracellular ATP concentration can be exploited to specifically target the TME, giving therapeutic antibodies the ability to overcome on-target off-tumor toxicity.

The Role of Preoperative and Postoperative Transversus Abdominis Plane and Rectus Sheath Block in Patients Undergoing Total Laparoscopic Hysterectomy.

PURPOSE: This study was performed to assess the efficacy of a preoperative and postoperative transversus abdominis plane (TAP) and rectus sheath (RS) block compared with no TAP and RS block in patients undergoing total laparoscopic hysterectomy (TLH). DESIGN: Prospective observational cohort study. METHODS: From January 2014 to December 2017, 195 women undergoing TLH were categorized into three groups based on their perioperative analgesia: no TAP + RS block (n = 88), preoperative TAP + RS block + systemic analgesia (n = 68), and postoperative TAP + RS block + systemic analgesia (n = 39). We evaluated use of nonsteroidal anti-inflammatory drugs (NSAIDs) and NSAID consumption within the first 12 hours postoperatively and the numerical rating scale score at 0, 12, and 24 hours postoperatively. FINDINGS: Women with a preoperative TAP + RS block had a significantly lower utilization rate of NSAIDs within the first 12 hours postoperatively (54.4% vs 75.0%; P = .007), lower postoperative flurbiprofen dose (45.5 vs 62.0 mg; P = .048), and lower numerical rating scale score at 12 hours postoperatively (1.63 vs 2.20; P = .002) compared with women with no TAP + RS block. CONCLUSIONS: A preoperative TAP + RS block provided superior postoperative analgesia in patients undergoing TLH and reduced analgesic consumption during the first 12 hours postoperatively.

Refractory secondary thrombotic microangiopathy with kidney injury associated with systemic lupus erythematosus in a pediatric patient.

Thrombotic microangiopathy (TMA) is generally diagnosed through clinical features characterized as microangiopathic hemolytic anemia, thrombocytopenia, and multiple organ injury, as well as by pathological findings such as vascular damage and endothelial cell injury. Rheumatic and autoimmune diseases could be accompanied by secondary TMA; in fact, systemic lupus erythematosus (SLE) is a common disease associated with secondary TMA, and SLE complicated with TMA has been reported to have a poor prognosis. Although TMA occurs rarely in pediatric SLE patients, it often leads to severe clinical conditions. Here, we report a rare case of severe juvenile-onset SLE complicated with TMA and kidney injury. The 5-year-old patient showed renal dysfunction, thrombocytopenia, hemolytic anemia, nephrotic syndrome, hypocomplementemia, and elevation of anti-dsDNA IgG levels. Kidney biopsy revealed mesangial proliferation and endocapillary proliferation, as well as plumped endothelial cells, with full-house pattern deposits in immunofluorescence study. Combination treatment of methylprednisolone pulse therapy followed by oral prednisolone, mycophenolate mofetil, and plasma exchange was effective, whereas eculizumab did not show therapeutic effects. The patient further showed recurrent deterioration, and we initiated intravenous cyclophosphamide in addition to combination treatment and eventually succeeded in controlling the disease. Genome analysis by whole-exome sequencing revealed no particular gene mutation related to either complement disorders or type-1 interferon. Further elucidations concerning the pathogenic mechanisms causing juvenile-onset SLE are needed to establish an efficient treatment strategy for TMA with SLE.

Pathological assessment of the lymph node biopsies for lymphadenopathy in rheumatoid arthritis.

Objectives: To assess the incidence of reactive lymph node hyperplasia (RLH) and the diagnostic characteristics that can help differentiate it from lymphoproliferative disorders (LPD) in patients with rheumatoid arthritis (RA).Methods: Data on patient characteristic from 32 consecutive RA patients with lymphadenopathy at a single medical center over a 6-year period were collected and analyzed to determine whether any of these characteristics can differentiated RLH from LPD.Results: LPD including methotrexate (MTX) - associated LPD (MTX-LPD) and RLH were diagnosed in 19 and 10 patients, respectively. Conclusive diagnosis was not reached in the remaining three cases and they were regarded as grey-zone cases. Age, levels of lactate dehydrogenase (LDH) and soluble interleukin-2 receptor (sIL-2R), as well as maximum standardized uptake value (SUVmax), were significantly higher in LPD than in RLH patients. The diagnosis cut-off values for these parameters were 66 year, 169 U/L, 899 U/mL and 8.18, respectively, based on the receiver operating characteristics curve analysis for both RLH and LPD.Conclusions: About one-third of patients with RA who presented with lymphadenopathy had reactive lymph node enlargement. Older age and higher levels of LDH, sIL-2R, and SUVmax are more associated with LPD than should be considered when deciding to perform a biopsy.

Influences of Total Laparoscopic Hysterectomy According to Body Mass Index (Underweight, Normal Weight, Overweight, or Obese).

STUDY OBJECTIVE: The aim of this study is to evaluate the effect of body mass index (BMI) on laparoscopic hysterectomy outcomes. DESIGN: This was retrospective study. SETTING: Minoh City Hospital, Japan. MATERIALS AND METHODS: Between January 1, 2014, and June 30, 2017, 183 patients underwent total laparoscopic hysterectomy (TLH) at our institution. INTERVENTION: Patients who underwent TLH were grouped according to BMI, as follows: underweight group (BMI <18.5 kg/m2), normal-weight group (18.5 ≤BMI <25 kg/m2), overweight group (25 ≤BMI <30 kg/m2), and obese group (BMI ≥30 kg/m2). MEASUREMENTS AND MAIN RESULTS: Information on patients' clinical characteristics and surgical results were collected retrospectively by medical record review. The severity of complications was graded according to the Clavien-Dindo classification. We assessed clinical characteristics, surgical results, and the perioperative complications in each BMI group. Surgical results included operation time, nonsurgical operating room time estimated blood loss, uterine weight, and postoperative hospital stay. Compared with the normal-weight group, the obese group had significantly more complications (P = 0.012) and longer operation time (P = 0.04). The underweight and overweight groups did not have significantly different surgical results than the normal-weight group. CONCLUSION: Underweight and overweight patients had no significant differences in surgical results, compared with patients of normal weight. Obese patients had significantly longer operation times and more perioperative complications than patients with normal weight. Laparoscopic hysterectomy has burdens and risks for obese patients. Our results suggest that appropriate weight control may decrease the risk of surgery for obese patients.

Diffusion-weighted Whole-body Imaging with Background Body Signal Suppression (DWIBS) as a Novel Imaging Modality for Disease Activity Assessment in Takayasu's Arteritis.

A 26-year-old woman with Takayasu's arteritis (TAK) experienced back and neck pain during tocilizumab (TCZ) treatment. The levels of C-reactive protein were normal, and ultrasonography revealed no significant changes. Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) showed signal enhancement in the walls of several arteries. Contrast computed tomography showed arterial inflammation in the same lesion. After increasing the dose of prednisolone and TCZ, all signal enhancements decreased and continued to decrease, as observed on days 76 and 132. Thus, DWIBS may be a novel imaging modality for assessing the disease activity of TAK, particularly during follow-up.

Crosstalk between tumor necrosis factor-alpha signaling and aryl hydrocarbon receptor signaling in nuclear factor -kappa B activation: A possible molecular mechanism underlying the reduced efficacy of TNF-inhibitors in rheumatoid arthritis by smoking.

OBJECTIVES: To examine the influence of smoking on biologics treatment against different therapeutic targets, such as TNFα, IL-6, and T cell, in rheumatoid arthritis (RA) and elucidate the underlying molecular mechanism. METHODS: The association between drug-discontinuation due to poor therapeutic response and smoking status was analyzed individually in biologics against different therapeutic targets by a multivariable logistic regression analysis using the "NinJa" Registry, one of the largest cohorts of Japanese RA patients. In vitro enhancement of TNFα-induced NF-κB activation and subsequent proinflammatory cytokine production by cigarette chemical components was examined by RT-PCR, qPCR, ELISA, and western blotting using an immortalized rheumatoid synovial cell line, MH7A. RESULTS: The rate of drug-discontinuation due to poor therapeutic response was higher in the current smoking group than in the never- or ever-smoking groups (the odds ratio of current/never smoking: 2.189, 95%CI; 1.305-3.672,P = 0.003; current/ever: 1.580, 95%CI; 0.879-2.839,P = 0.126) in the TNF inhibitor (TNFi) treatment group. However, this tendency was not observed in either the IL-6 or T cell inhibitor treatment groups. Cigarette smoke chemical components, such as benzo[α]pyrene, known as aryl hydrocarbon receptor (AhR) ligands, themselves activated NF-κB and induced proinflammatory cytokines, IL-1ß and IL-6. Furthermore, they also significantly enhanced TNFα-induced NF-κB activation and proinflammatory cytokine production. This enhancement was dominantly inhibited by Bay 11-7082, an NF-κB inhibitor. CONCLUSIONS: These results suggest a crosstalk between TNFα signaling and AhR signaling in NF-κB activation which may constitute one of the molecular mechanisms underlying the higher incidence of drug-discontinuation in RA patients undergoing TNFi treatment with smoking habits.

A review of clinical characteristics and genetic backgrounds in Alport syndrome.

Alport syndrome (AS) is a progressive hereditary renal disease that is characterized by sensorineural hearing loss and ocular abnormalities. It is divided into three modes of inheritance, namely, X-linked Alport syndrome (XLAS), autosomal recessive AS (ARAS), and autosomal dominant AS (ADAS). XLAS is caused by pathogenic variants in COL4A5, while ADAS and ARAS are caused by those in COL4A3/COL4A4. Diagnosis is conventionally made pathologically, but recent advances in comprehensive genetic analysis have enabled genetic testing to be performed for the diagnosis of AS as first-line diagnosis. Because of these advances, substantial information about the genetics of AS has been obtained and the genetic background of this disease has been revealed, including genotype-phenotype correlations and mechanisms of onset in some male XLAS cases that lead to milder phenotypes of late-onset end-stage renal disease (ESRD). There is currently no radical therapy for AS and treatment is only performed to delay progression to ESRD using nephron-protective drugs. Angiotensin-converting enzyme inhibitors can remarkably delay the development of ESRD. Recently, some new drugs for this disease have entered clinical trials or been developed in laboratories. In this article, we review the diagnostic strategy, genotype-phenotype correlation, mechanisms of onset of milder phenotypes, and treatment of AS, among others.

A postzygotic KRAS mutation in a patient with Schimmelpenning syndrome presenting with lipomatosis, renovascular hypertension, and diabetes mellitus.

Schimmelpenning syndrome is a rare neurocutaneous disorder categorized as a mosaic RASopathy due to postzygotic HRAS or KRAS mutations. We report a 6-year-old girl diagnosed with Schimmelpenning syndrome due to a postzygotic KRAS G12D mutation. The patient had three atypical symptoms of Schimmelpenning syndrome: renovascular hypertension, congenital lipomatosis, and diabetes mellitus. The first two symptoms may overlap with phenotypes of other neurocutaneous syndromes or congenital lipomatous overgrowth syndrome due to mosaic RASopathies or other somatic mosaic mutations. We propose that impaired glucose tolerance was caused by KRAS mutation and a novel clinical phenotype of Schimmelpenning syndrome. Our study indicated that clinical diagnosis of Schimmelpenning syndrome or related conditions should be reorganized with genetic diagnosis of postzygotic mutation. Moreover, further accumulation of genetically proven cases with mosaic RASopathies should be used to more accurately characterize phenotypic presentations of this syndrome and develop a future therapeutic strategy, such as molecular-targeted therapy.

Neurofilament heavy polypeptide protects against reduction in synaptopodin expression and prevents podocyte detachment.

Podocytes are highly specialized cells that line the glomerulus of the kidney and play a role in filtration. Podocyte injury plays a critical role in the development of many kidney diseases, but the underlying mechanisms remain unclear. In this study, we identified that neurofilament heavy polypeptide (NEFH), an intermediate filament component, protects podocyte from injury. We observed that NEFH was upregulated after ADRIAMYCIN(ADR)-induced podocyte injury in both mice and cultured murine podocytes. Immunofluorescence and co-immunoprecipitation analyses revealed that NEFH was colocalized with synaptopodin, a podocyte-specific marker. High NEFH expression in podocytes prevented the Adriamycin-induced reduction in synaptopodin expression. The siRNA-mediated knockdown of NEFH in podocytes reduced the number of vinculin-containing focal contacts, thereby reducing adhesion to the extracellular matrix and increasing podocyte detachment. In addition, NEFH expression was significantly increased in renal biopsy specimens from patients with focal segmental glomerulosclerosis and membranous nephropathy, but in those with minimal change disease. These findings indicate that NEFH is expressed in podocytes during the disease course and that it prevents the reduction in synaptopodin expression and detachment of podocytes.

Rac1 in podocytes promotes glomerular repair and limits the formation of sclerosis.

Rac1, a Rho family member, is ubiquitously expressed and participates in various biological processes. Rac1 expression is induced early in podocyte injury, but its role in repair is unclear. To investigate the role of Rac1 expression in podocytes under pathological conditions, we used podocyte-specific Rac1 conditional knock-out (cKO) mice administered adriamycin (ADR), which causes nephrosis and glomerulosclerosis. Larger areas of detached podocytes, more adhesion of the GBM to Bowman's capsule, and a higher ratio of sclerotic glomeruli were observed in Rac1 cKO mice than in control mice, whereas no differences were observed in glomerular podocyte numbers in both groups after ADR treatment. The mammalian target of rapamycin (mTOR) pathway, which regulates the cell size, was more strongly suppressed in the podocytes of Rac1 cKO mice than in those of control mice under pathological conditions. In accordance with this result, the volumes of podocytes in Rac1 cKO mice were significantly reduced compared with those of control mice. Experiments using in vitro ADR-administered Rac1 knockdown podocytes also supported that a reduction in Rac1 suppressed mTOR activity in injured podocytes. Taken together, these data indicate that Rac1-associated mTOR activation in podocytes plays an important role in preventing the kidneys from developing glomerulosclerosis.

[Numerical and Visual Evaluation of Compressed Sensing MRI Using 3D Cartesian Sampling].

We performed numerical and visual evaluation of compressed sensing MRI (CS-MRI) using 3D Cartesian sampling by numerical simulation. Three brain anatomical ROIs (white matter, gray matter, cerebrospinal fluid) of a T1-weighted image (T1WI), a T2-weighted image (T2WI) and a proton density-weighted image (PDWI) were used for numerical evaluation. Sampling ratio of the Cartesian grid was 30%. Reconstruction was performed by the projection onto convex sets (POCS) method with soft thresholding, subject to data fidelity constraints. In the absence of noise, RMSE of 3D-T1WI was 1.50, ant that of the 2D-T1WI of the transverse plane was in the range of 1.06 to 1.54; anatomical ROIs was in the range of 0.75 to 2.80; those of T2WI were 3.20, 2.77 to 3.06, and 1.81 to 4.51; those of PDWI were 1.69, 1.33 to 1.49, and 1.08 to 1.86. Visual evaluation was performed by three radiologists on the basis of three categories: artifact, anatomical structure, and tissue contrast. Average score of the visual evaluation indicated that anatomical structure and tissue contrast of CS images were equal to those of the original image, although a few artifacts were visible. If noise level was assumed to be 20 dB or less, anatomical structure and tissue contrast were not significantly degraded compared to noise-free CS images.

Re-expression of Sall1 in podocytes protects against adriamycin-induced nephrosis.

The highly conserved spalt (sal) gene family members encode proteins characterized by multiple double zinc finger motifs of the C2H2 type. Humans and mice each have four known Sal-like genes (SALL1-4 in humans and Sall1-4 in mice). Sall1 is known to have a crucial role in kidney development. To explore the significance of Sall1 in differentiated podocytes, we investigated podocyte-specific Sall1-deficient mice (Sall1 KOp°d°/p°d°) using a podocin-Cre/loxP system and siRNA Sall1 knockdown (Sall1 KD) podocytes. Under physiological conditions, Sall1 KOp°d°/p°d° mice exhibited no proteinuria during their lifetime, but foot-process effacement was detected in some of the podocytes. To elucidate the role of Sall1 in injured podocytes, we used an adriamycin (ADR)-induced model of nephrosis and glomerulosclerosis. Surprisingly, the expression of Sall1 was elevated in control mice on day 14 after ADR injection. On day 28 after ADR injection, Sall1 KOp°d°/p°d° mice exhibited significantly higher levels of proteinuria and higher numbers of sclerotic glomeruli. Differentiated Sall1 KD podocytes showed a loss of synaptopodin, suppressed stress fiber formation, and, ultimately, impaired directed cell migration. In addition, the loss of Sall1 increased the number of apoptotic podocytes following ADR treatment. These results indicated that Sall1 has a protective role in podocytes; thus, we investigated the endoplasmic reticulum stress marker GRP78. GRP78 expression was higher in ADR-treated Sall1 KOp°d°/p°d° mice than in control mice. Sall1 appeared to influence the expression of GRP78 in injured podocytes. These results suggest that Sall1 is associated with actin reorganization, endoplasmic reticulum stress, and apoptosis in injured podocytes. These protective aspects of Sall1 re-expression in injured podocytes may have the potential to reduce apoptosis and possibly glomerulosclerosis.