[Focal segmental glomerulosclerosis: Pathogenesis, pathophysiology, and therapy].
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Actinin↗
Biomedical subjects
Masahiro Hagiwara
Publications and source records attributed to Masahiro Hagiwara.
Polyclonal activation of an IgA subclass against Staphylococcus aureus cell membrane antigen in post-methicillin-resistant S. aureus infection glomerulonephritis.
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Antigens, Bacterial↗
Age distribution and yearly changes in the incidence of ESRD in Japan.
BACKGROUND: Although several treatment and screening methods have been tried, the incidence of patients with end-stage renal disease (ESRD) on renal replacement therapy (RRT) continues to increase worldwide. By making a detailed analysis of the major primary renal diseases, we found there have been some favorable effects in the incidence rate of ESRD recently in Japan. METHODS: A total of 339,478 patients in Japan and 909,591 patients in the United States started RRT between 1983 and 1999. We compared trends of average age and incidence rate in each age group with major primary renal diseases and in racial groups after adjusting for general population aging by using a linear regression analysis. RESULTS: All trends in ESRD incidence rates among Japanese, US total, US white, and US black patients showed significant increases (P < 0.001). A significant positive linear relationship between year and mean age at start of RRT also was observed (P < 0.001). After adjustment for general population aging, the mean age increment in Japanese patients with glomerulonephritis was increased significantly, and the proportion of Japanese patients who had glomerulonephritis and were younger than 45 years was decreased, but this decrement was not observed in US patients with glomerulonephritis. CONCLUSION: The reduced number of new patients with ESRD with glomerulonephritis might be caused by early detection and early referral to nephrologists as a result of the Japanese urinalysis-screening program. To reduce the ESRD population, it will be necessary to establish more effective treatment methods to delay exacerbation of progressive renal diseases.
Adult↗
[Mitochondrial dysfunction and focal segmental glomerular sclerosis].
Focal segmental glomerular sclerosis (FSGS) is known as one of major renal complication of mitochondrial cytopathies. Glomerular epithelial cells are primary pathogenic sites in FSGS lesions. Glomerular epithelial cells are regarded as terminally differentiated cells and do not proliferate. This characteristic is the same for neuron cells and muscular cells, which are major sites of mitochondrial DNA mutations accumulation. Accumulation of mitochondrial DNA mutations might induce mitochondrial dysfunction and lead to FSGS lesion in glomeruli or these accumulations are only consequences of pathogenic stimuli to glomerular epithelial cells during the disease course of several glomerulopathies. Further investigations are needed to clarify pathogenic role of mitochondria and mitochondrial DNA mutations.
DNA, Mitochondrial↗
Mitochondrial DNA mutations in focal segmental glomerulosclerosis lesions.
Glomerular epithelial cells are primary pathogenic sites in focal segmental glomerulosclerosis (FGS) lesions. Glomerular epithelial cells are regarded as terminally differentiated cells that do not proliferate. These characteristics are also noted for neurons and muscular cells, which are major sites of mitochondrial DNA (mtDNA) mutation accumulation. Screening for mtDNA mutations was performed with renal biopsy specimens from patients with primary FGS and patients with IgA nephropathy (as subjects with secondary FGS and as control subjects). mtDNA extracted from kidney biopsy specimens was amplified with appropriate primer pairs for study of the mtDNA point mutations 3243A-->G, 3271T-->C, 8344A-->G, and 8993T-->G/C, as well as the common deletion (a 4977-bp deletion spanning mtDNA nucleotide pairs 8469 to 13447). In situ amplification of both total mtDNA and the common deletion was also performed. Two patients with FGS demonstrated the 3243A-->G point mutation; 12 patients with FGS and seven patients with IgA nephropathy accompanied by glomerulosclerotic lesions exhibited the common deletion in their kidney tissue. No patient demonstrated the mtDNA mutations 3271T-->C, 8344A-->G, or 8993T-->G/C. The degree of heteroplasmy for the 3243A-->G point mutation was >85%; however, the heteroplasmy for the common deletion was <1%. As determined with in situ PCR, normal mtDNA was mainly distributed in the tubular epithelium and mtDNA with the common deletion was mainly distributed among glomerular epithelial cells. In conclusion, it is suggested that mtDNA mutations are distributed in glomerular epithelial cells among some patients with primary FGS or secondary FGS with IgA nephropathy. These mutations may be related to glomerular epithelial cell damage.
Adolescent↗
Staphylococcus aureus antigens induce IgA-type glomerulonephritis in Balb/c mice.
BACKGROUND: Staphylococcus aureus (S. aureus) is a common, normal pathogenic flora that colonizes mucosal tissues. We previously reported that glomerulonephritis occurs during methicillin-resistant S. aureus infection, and demonstrated polyclonal elevation of serum immunoglobulin A (IgA) and IgG levels and various histological findings, such as mesangial extracapillary and endocapillary proliferation. To investigate the pathogenic roles of S. aureus antigens, we induced IgA-type glomerulonephritis in mice by immunization with antigens derived from S. aureus, as a model of human IgA nephropathy (IgAN). METHODS: Balb/c mice (Th2 dominant type) and C57BL/6 mice (Th1 dominant type) were immunized biweekly for 4 months with antigens derived from S. aureus mixed with Freund's incomplete adjuvant. RESULTS: Mesangial proliferative glomerulonephritis with IgA, IgG and complement 3 (C3) depositions were observed in all Balb/c mice. Although C3 depositions and cell proliferation in the mesangial area were also seen in C57BL/6 mice, they were not correlated with urinary findings. In Balb/c mice, S. aureus antigens were detected in glomeruli using affinity-purified human anti-S. aureus antibodies, but there was no staining in C57BL/6 mice. The antibodies reacted with several S. aureus antigens, based on Western blot analysis, and the main 30-35 kDa band differed in intensity in Balb/c and C57BL/6 mice. In addition, increased transforming growth factor beta (TGF-beta) messenger RNA (mRNA) expression was seen in Balb/c mice compared to C57BL/6 mice. CONCLUSIONS: S. aureus antigens including, in particular, a 30-35 kDa protein and the host genetic background could play important roles in IgA-like glomerulonephritis pathogenesis.
Analysis of Variance↗
Post-MRSA infection glomerulonephritis with marked Staphylococcus aureus cell envelope antigen deposition in glomeruli.
A 48-year-old male developed massive proteinuria and renal dysfunction after pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) infection. Examination of a renal biopsy specimen by light microscopy showed severe mesangiocapillary proliferative glomerulonephritis with fibrocellular crescents. Immunofluorescence microscopy showed weak linear staining for immunoglobulin G (IgG), while both the peripheral and mesangial lesions stained for IgA and C3. Immunostaining for a possible antigen related to post-MRSA infection glomerulonephritis, using monoclonal antibody S1D6, revealed marked deposition of S.aureus cell envelope antigen in the glomeruli. Electron-dense deposits were observed in both the subendothelial and the mesangial areas. Focal subendothelial widening accompanied with monocytes or foam cell infiltration was also seen. The findings reflect a typical post-MRSA infection glomerulonephritis caused by S.aureus cell envelope antigen.
Antigens, Bacterial↗