Minoru Sakatsume

Comparison of gastroduodenal, renal and abdominal fat biopsies for diagnosing amyloidosis in rheumatoid arthritis.

Abstract: The aim of the study was to determine the frequency of amyloidosis detected by gastroduodenal biopsy in rheumatoid arthritis (RA) patients, and to investigate correlations between the results of gastroduodenal biopsy and abdominal fat and renal biopsies. A total of consecutive 1006 RA patients underwent gastroduodenal biopsy. The 71 patients who tested positive for gastrointestinal (GI) amyloidosis were asked to undergo renal and abdominal fat biopsies, and 21 did so. Renal biopsies were also performed on 12 patients with no amyloidosis but indicators of drug-induced renal damage, and abdominal fat biopsies were performed on 50 RA patients with no indication of amyloidosis. The prevalence of GI amyloidosis was 7.1%. Urinary abnormalities and GI symptoms were common in GI amyloidisis, and inflammatory markers were elevated. Sixty-one (86%) had either depressed creatinine clearance or urinary symptoms. Nineteen of the 21 patients (91%) with GI amyloidosis who underwent renal biopsies also had renal amyloid deposits. Eleven of the 21 (52%) had amyloidosis on abdominal fat biopsy. None of the 12 patients without GI amyloidosis had renal amyloidosis on renal biopsy, and none of the 50 patients without GI amyloidosis had amyloidosis on abdominal fat biopsy. Gastroduodenal biopsy reveals a high prevalence of amyloidosis in RA patients. Amyloidosis is often associated with signs of renal impairment. Results of GI biopsy are highly correlated with those of renal biopsy, but the results of fat biopsy are not. We recommend GI biopsy for RA patients for the screening of systemic amyloidosis.

Monocyte chemoattractant protein-1 A-2518G gene polymorphism and renal survival of Japanese patients with immunoglobulin A nephropathy.

BackgroundMonocyte chemoattractant protein (MCP)-1 is closely related to the pathogenesis of the progression of various chronic renal diseases, including IgA nephropathy (IgAN), through its chemoattractant effect on macrophages. However, the correlation of MCP-1 gene polymorphism with the long-term prognosis of Japanese patients with IgAN has not been clearly determined yet.MethodsWe investigated 277 Japanese patients diagnosed with IgAN based on renal biopsy to clarify the association between the progression of IgAN and MCP-1 gene polymorphism at position A-2518G, which regulates the transcription of the MCP-1 gene.ResultsThe incidence of endstage renal disease was significantly higher in patients with the AA genotype (47.1%) compared to those with the AG (24.1%) or GG (27.4%) genotype (P = 0.024). Moreover, Kaplan-Meier analysis revealed that the AA genotype significantly facilitated the progression of renal disease (log rank; P = 0.0029), and Cox proportional hazards regression model analysis showed that the AA genotype represented a 2.058-fold risk for the progression of renal disease (P = 0.026) compared to the AG/GG genotype. However, when the patients were treated with angiotensin-converting enzyme inhibitor and/or angiotensin receptor blocker, or corticosteroid, homozygosity for the -2518A allele was not associated with a higher rate of incidence of endstage renal disease. Serum MCP-1 levels were higher although not significantly so, in the patients with IgAN possessing the AA genotype.ConclusionsThe AA genotype at MCP-1 -2518 was an independent risk factor for the progression of renal disease in Japanese patients with IgAN, and was closely associated with renal survival.

A case of AA amyloidosis associated with rheumatoid arthritis effectively treated with Infliximab

We report the case of a 55-year-old Japanese woman with reactive AA amyloidosis associated with rheumatoid arthritis, in which inflammatory disease was completely suppressed with infliximab. Nephrotic syndrome was observed and renal biopsy specimens revealed amyloidosis deposits. Treatment with infliximab normalized the serum amyloid A (SAA) protein level, and subsequently nephritic syndrome disappeared and her creatinine clearance improved. Serial gastrointestinal biopsy specimens showed marked lasting regression of amyloid deposits. Thus treatment with infliximab represents an important therapeutic strategy for AA amyloidosis associated with RA.

SM22α: The Novel Phenotype Marker of Injured Glomerular Epithelial Cells in Anti-Glomerular Basement Membrane Nephritis

Background/Aims: Our previous comprehensive analysis of the genes expressed in kidneys with anti-glomerular basement membrane (GBM) nephritis using DNA microarrays showed that SM22α was one of the highly expressed genes. SM22α is a 22-kDa cytoskeletal protein that is exclusively expressed in smooth muscle cells. We investigated the localization of SM22α at mRNA and protein levels, and its pathological significance in anti-GBM nephritis kidneys. Methods: Northern blot analysis, in situ hybridization, immunohistochemistry and double immunofluorescence studies were performed. The specific antibody (Ab) against SM22α was obtained by immunization of rabbits with recombinant rat SM22α protein. Results: SM22α mRNA expression was upregulated in kidneys and inducibly expressed in the parietal and visceral glomerular epithelial cells in anti-GBM nephritis kidneys. Immunohistochemistry with anti-SM22α Ab showed that SM22α protein was localized in the same series of cells. Double immunofluorescence with anti-SM22α and anti-glomerular cell markers demonstrated that SM22α might be expressed in epithelial cells of injured glomeruli. In visceral epithelial cells, SM22α might be expressed in cells in which podocyte specific markers, podocalyxin and nephrin were lost. Conclusion: The injured glomerular epithelial cells in anti-GBM nephritis might undergo structural and functional alterations, including the expression of a smooth muscle marker, SM22α.

Genetic Polymorphism of NPHS1 Modifies the Clinical Manifestations of Ig A Nephropathy

Nephrin, the molecule responsible for congenital nephrotic syndrome of Finnish type, is crucial in maintaining the glomerular filtration barrier. Recently, its complete gene structure and common gene polymorphisms in its exons have been reported, although the functional and clinical significance of these polymorphisms has not yet been elucidated. We investigated a possible association of the NPHS1 polymorphisms with the development of Ig A nephropathy (IgAN), as well as the clinical and histologic manifestations in IgAN. A total of 464 Japanese subjects, including 267 patients with histologically proven IgAN and 197 healthy controls with normal urinalysis, were genotyped for the NPHS1 G349A, G2289A, and T3315C polymorphisms. The frequencies of the genotypes, alleles, and estimated haplotypes of NPHS1 polymorphisms were no different between patients with IgAN and the controls. Within the IgAN group, patients carrying at least one G allele of G349A tended to present with more proteinuria, lower renal function, and more severe histopathologic injury than those with the AA genotype, although the time from the first urinary abnormality to the renal biopsy was no different between both groups. The logistic regression analysis indicated that even after adjusting for the effect of proteinuria and hypertension the GG genotype of NPHS1 G349A was an independent risk factor for the deteriorated renal function at the time of diagnosis. This study suggests that the NPHS1 G349A polymorphism may be associated with heavy proteinuria and a decline in renal function in patients with IgAN.

Genetic polymorphisms in the promoter and 5′ UTR region of the Fc α receptor (CD89) are not associated with a risk of IgA nephropathy

AbstractThe molecular mechanisms of immunoglobulin A glomerulonephritis (IgAN), the most prevalent form of primary glomerulonephritis, remain poorly understood. Recently, the essential role of soluble Fc α receptor (FcαR) in the formation of the pathogenic immune complex has been revealed. We screened genomic DNA samples from patients with IgAN and those with other glomerular diseases for polymorphisms in the promoter and the 5′-untranslated region region of the FcαR gene by direct nucleotide sequencing. We found three common polymorphisms in this region, T-114C, T-27C, and T+56C from the putative transcription initiation site. Each genotype was determined in 151 patients with IgAN and 163 patients with other glomerular diseases shown to have no mesangial IgA deposition by renal biopsy. The haplotype analysis revealed tight linkage disequilibrium among them. An association study for the genotype, allele, and haplotype frequencies of the polymorphisms between the patients with histologically proven IgAN and those with other glomerular diseases showed no significant difference in the genotype, allele, and haplotype distributions between the two groups. The present study indicates that the analyzed polymorphisms of the FcαR gene do not appear to be primarily involved in the susceptibility to IgAN.

Rapid and sensitive electrophoresis of urinary protein clearly reveals the pathophysiological feature of renal diseases

Aim:  The diagnostic approach for renal diseases with the electrophoretic pattern of urinary protein on cellulose acetate (CA) membrane differentiates the causes of proteinuria. However, this method has not been used routinely because of its difficulty in obtaining a clear image. This study was performed in order to re‐evaluate this method with an improved system.

Association of the MCP-1 gene polymorphism A-2518G with carpal-tunnel syndrome in hemodialysis patients.

Abstract Carpal-tunnel syndrome (CTS) in long-term hemodialysis patients is caused by the deposition of amyloid as well as by the local inflammatory process. The recruitment of monocytes/macrophages in the tenosynovium, promoted by chemokines such as monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1a (M1P-I α), is thought to play an important role in CTS development. The genetic polymorphism of these chemokines has been identified and their clinical function has been partly revealed. We attempted to analyze the relationship between these polymorphisms and their susceptibility to CTS. The subjects of this study were 366 patients who underwent hemodialysis. Ninety-five patients received surgery for CTS. No significant difference was observed in the genotype distributions of MCP-1 or MIP-lα between patients who received CTS surgery and those that did not. However, with the use of a logistic regression model, the MCP-1 GG genotype was identified as a risk factor for the development of CTS, in addition to the duration and the age of initiation of dialysis, as confirmed by a Cox proportional hazards model. In conclusion, homozygosity for G at -2518 in the MCP-1 gene might be a candidate for the genetic marker of CTS development in Japanese hemodialysis patients.

Mortality Predictors after 10 Years of Dialysis: A Prospective Study of Japanese Hemodialysis Patients

BACKGROUND This work aimed to examine the predictive value for death of various clinical variables after long-term hemodialysis (HD). DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS A total of 947 patients (597 men and 350 women, aged 21 to 93 yr) who were undergoing maintenance HD in Niigata, Japan, were stratified into two cohorts: Those with >10 yr of prior HD at study enrollment (n = 391) and those with < or =10 yr of previous therapy (n = 556). The survival of patients was examined for up to 40 mo (1999 to 2003) with the Cox proportional hazards model. Baseline clinical and dialysis data and serum biochemistries were used as independent variables. For adjustment for bias in patient selection, patient survival in either cohort was analyzed separately. RESULTS In patients with >10 yr of HD, high pulse pressure, cerebrovascular disease, low serum creatinine, and low Kt/V values were the mortality risk predictors, whereas for those with < or =10 yr of HD, age and cerebrovascular disease were independent risk predictors for death. Diabetes, coronary artery disease, serum albumin, and C-reactive protein were NS predictors in those with long-term HD. CONCLUSIONS Providing adequate dosage of dialysis and achieving a better control of pulse pressure may further improve survival in selected patients who had undergone HD for >10 yr.

Molecular heterogeneity of urinary albumin in glomerulonephritis: Comparison of cardiovascular disease with albuminuria

BACKGROUND Despite the unstable structure of urinary albumin in kidney diseases, urinary albumin fragments have been identified by denaturing methods such as two-dimensional electrophoresis. This study examined the relationship between the structural heterogeneity of urinary albumin and protease effects. METHODS Urine samples from patients with glomerulonephritis (GN), cardiovascular diseases (CVD), and healthy subjects were analyzed by non-reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE), Western blot, diagonal 2-dimensional non-reducing/reducing (d2D) SDS PAGE, and albumin zymography. RESULTS The major band was monomer albumin in CVD and healthy subjects; however, 13 urinary albumin bands ranging from 55 to 172 kDa were identified by non-reducing SDS PAGE in GN. The results from d2D SDS PAGE showed urinary albumin polymerization between disulfide bridges, interactions with other proteins, and reduction induced degradation in GN patients. The results from albumin zymography showed that low-molecular mass forms of albumin did not necessarily correspond to high protease activity. Furthermore, concentrated healthy urine showed similar protease digestion as in GN without low-molecular mass of albumin. CONCLUSIONS The molecular alterations observed cannot be explained only by urinary proteases. The specific alteration of urinary albumin molecules in GN can be attributed to different mechanisms to CVD.