Survey of Japanese nephrologists' use of clinical practice guidelines for rapidly progressive glomerulonephritis.

BACKGROUND: The guidelines in Japan for the treatment of rapidly progressive glomerulonephritis (RPGN) have been revised; the latest update was released in 2020. We investigated the actual usage of the new guidelines in Japan. METHODS: We distributed a survey electronically to board-certified nephrologists throughout Japan from December 15, 2021 to January 31, 2022. The survey focused on anti-neutrophil cytoplasmic antibody (ANCA)-associated RPGN and anti-glomerular basement membrane (GBM)-antibody RPGN, plus the treatment strategies and infection-prevention measures used. RESULTS: The survey was completed by 155 certified nephrologists from medical facilities across Japan. Their responses regarding treatment procedures revealed that ANCA-associated RPGN was treated with immunosuppressants and/or biologics by 58.1% of the survey respondents, and with plasma exchange (PE) in combination with corticosteroids by 21.3%. Regarding anti-GBM-antibody RPGN, 78.1% of the respondents used corticosteroids in combination with PE (63.2%), cyclophosphamide (CY) (23.9%), or rituximab (RTX) (8.4%), suggesting a discrepancy between clinical practice and the actual use of the guidelines. Trimethoprim-sulfamethoxazole was prescribed as prophylaxis by 94.8% of the respondents, reflecting the widespread recognition of the need to prevent infectious disease in patients with RPGN. CONCLUSIONS: The survey responses revealed how Japan's new RPGN guidelines are used in actual clinical practice. Our findings will contribute to the guidelines' dissemination and implementation.

Mitochondrial DNA deletion-dependent podocyte injuries in Mito-miceΔ, a murine model of mitochondrial disease.

Focal segmental glomerulosclerosis (FSGS) is a major renal complication of human mitochondrial disease. However, its pathogenesis has not been fully explained. In this study, we focused on the glomerular injury of mito-miceΔ and investigated the pathogenesis of their renal involvement. We analyzed biochemical data and histology in mito-miceΔ. The proteinuria began to show in some mito-miceΔ with around 80% of mitochondrial DNA deletion, then proteinuria developed dependent with higher mitochondrial DNA deletion, more than 90% deletion. Mito-miceΔ with proteinuria histologically revealed FSGS. Immunohistochemistry demonstrated extensive distal tubular casts due to abundant glomerular proteinuria. Additionally, the loss of podocyte-related protein and podocyte's number were found. Therefore, the podocyte injuries and its depletion had a temporal relationship with the development of proteinuria. This study suggested mitochondrial DNA deletion-dependent podocyte injuries as the pathogenesis of renal involvement in mito-miceΔ. The podocytes are the main target of mitochondrial dysfunction originated from the accumulation of mitochondrial DNA abnormality in the kidney.

Immunohistological score of transcription factor 21 had a positive correlation with its urinary excretion and proteinuria in immunoglobulin A nephropathy.

Transcription factor 21 (TCF21) contributes to mammalian nephrogenesis, and especially to glomerular maturation. Our previous study suggested its influence on glomerular injury, showing that TCF21 expression in podocytes had a positive correlation with the urinary protein value and also with the urinary TCF21 concentration. We now focus on its influence on the clinical course of immunoglobulin A nephropathy (IgAN), as patients with IgAN constitute the largest population of individuals with primary chronic glomerulonephritis in the world. Twenty cases of IgAN were divided into two groups according to the immunohistological score (IHS) of glomerular TCF21 expression: group IHS1 (n=7) and group IHS2+3 (n=13). Sixteen of the 20 cases were followed up for 2 years. Group IHS2+3 had heavier urinary protein (p=0.03) and a greater urinary TCF21 level (p<0.001) compared to group IHS1 at baseline. None of the other factors including hematuria, estimated glomerular filtration rate (eGFR), or the Oxford classification showed a statistically significant difference between these two groups. At the 2-year follow-up, even though the rate of remission in urinary protein, hematuria and the eGFR decline were not statistically correlated to IHS, the IHS2+3 group had a slight tendency toward a steeper eGFR decline compared to IHS1 (p=0.31). The present study suggested that the higher IHS of TCF21 corresponded to heavier proteinuria and a higher urinary TCF21 level in IgAN. This could be the first step in determining the TCF21 value for predicting the prognosis for IgAN.

Literature review of allograft adenovirus nephritis and a case presenting as mass lesions in a transplanted kidney without symptoms of urinary tract infection or acute kidney injury.

Adenovirus (AdV) infection is a common complication in bone marrow/hematopoietic stem cell transplant and solid organ transplant recipients. AdV infection usually presents as hemorrhagic cystitis, but sometimes it can progress to acute kidney injury showing AdV nephritis (AdVN). We present the case of a 52-year-old Japanese female who had received a living kidney transplantation (KT) from her husband. At 21 months post-KT, the patient presented with a fever, but no renal dysfunction and no abnormal urine findings. A contrast-enhanced computed tomography (CT) scan revealed a few mass lesions with hypoperfusion in the transplanted kidney. An enhanced CT-guided biopsy targeting one of these lesions revealed a necrotizing tubulointerstitial nephritis suggesting AdVN. The polymerase chain reaction tests for ADV were negative in a urine sample but positive in the sera and the frozen kidney biopsy samples. AdVN can manifest as an unusual pattern of acute lobar nephritis/acute focal bacterial nephritis-like localization without symptoms of acute kidney injury or urinary tract infection. Enhanced CT can provide clues for clinical diagnosis.

Anti-glomerular Basement Membrane Glomerulonephritis During the First Trimester of Pregnancy.

A 28-year-old woman was admitted during the eighth week of her pregnancy because her clinical course was consistent with rapid progressive glomerulonephritis (RPGN). Anti-glomerular basement membrane antibody (anti-GBM Ab) and myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) were positive, and the anti-GBM Ab titer being extremely high. She was treated with hemodialysis, plasma exchange and prednisolone. She survived the illness; however, neither the fetus nor her kidney function could be rescued. She had human leukocyte antigen (HLA)-DRB1*1502:01, which differs from the DRB1*1501 associated with anti-GBM GN. When patients have particular symptoms, we should check the urine and serum creatinine to exclude RPGN, even in cases of pregnancy.

Transcription factor 21 expression in injured podocytes of glomerular diseases.

Transcription factor 21 (TCF21) is one of the essential transcription factors in kidney development. To elucidate its influence on glomerular disease, we have investigated TCF21 expression in human and rat kidney tissue, and its urinary concentration. Immunohistological analysis suggested the highest TCF21 expression in nephrotic syndrome along with the urinary protein level. Urinary TCF21 concentration in human showed a positive correlation with its podocyte expression level. In nephrotic rat models, TCF21 expression in podocytes increased along with the severity of nephrotic syndrome. Next, in vitro experiments using Tcf21-expressing murine podocyte cell line, we could observe some Tcf21-dependent effects, related with actin cytoskeleton dysregulation and apoptosis. Our study illustrated TCF21 expression changes in vivo and its in vitro-functional significance injured podocytes.

Age-dependent survival in rapidly progressive glomerulonephritis: A nationwide questionnaire survey from children to the elderly.

BACKGROUND: Rapidly progressive glomerulonephritis (RPGN) has been known to have a poor prognosis. Although evidence across adult RPGN cases has accumulated over many years, the number of case series in adolescents and young adults has been limited, requiring further studies. METHODS: A total of 1,766 cases from 1989 to 2007 were included in this nationwide questionnaire survey, led by Intractable (former name, Progressive) Renal Diseases Research, Research on intractable disease, from the Ministry of Health, Labour and Welfare of Japan. To elucidate age-related differences in 2-year patient and renal survival rates, the cases were divided into the following four groups: children (0-18 years), young adults (19-39 years), the middle-aged (40-64 years), and the elderly (over 65 years). RESULTS: Of the 1,766 total RPGN cases, antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis comprised 1,128 cases (63.9% of all RPGN cases), showing a tendency to increase with age. Two-year patient survival for RPGN was 93.9% among children, 92.6% in young adults, 83.2% in the middle-aged, and 68.8% in the elderly. The younger group (children plus young adults) showed a clearly higher survival rate compared to the older group (middle-aged plus elderly) (p<0.05). ANCA-associated glomerulonephritis also showed similar age-related results with all RPGN cases. The comparison of renal prognosis showed no statistically significant differences both in RPGN and in ANCA-associated GN. CONCLUSION: The present study described the age-dependent characteristics of the classification of RPGN, especially focusing on a better prognosis of the younger group in patient survival both in RPGN and in ANCA-associated GN.

Kidney transplant patient with immunoglobulin A nephropathy subsequently diagnosed as concurrent autosomal dominant polycystic kidney disease during 17-year follow-up.

A 14-year-old Japanese boy was diagnosed with immunoglobulin A nephropathy resulting in end-stage kidney disease (ESKD). He underwent ABO-compatible living kidney transplantation from his father at the age of 27. In the process of selecting a donor before the transplantation, it turned out that his mother had polycystic kidneys and that her family had a history of hypertension and cerebrovascular diseases. The patient himself also had bilateral multiple kidney cysts, with a normal-sized kidney, confusing us to make the diagnosis of acquired cystic kidney disease (ACKD) or ADPKD difficult at that point. Seventeen years later, his native kidneys showed bilateral swelling with multiple cysts. This, along with the histories of his mother and her relatives and with the existence of multiple liver cysts, led us to confirm the diagnosis of autosomal dominant polycystic kidney disease, not of ACKD. Contrary to previous studies that have suggested the size of cysts both in ADPKD and ACKD reduced with time, the present case showed an increase of 3.0% per year in total kidney volume (TKV) by computed tomography. It suggested the possibility that TKV, after decreasing in the relatively early stage after transplantation, may later increase in the long term after ESKD due to another kidney injury.