Wako Yumura

A functional variant in FCRL3, encoding Fc receptor-like 3, is associated with rheumatoid arthritis and several autoimmunities

Rheumatoid arthritis is a common autoimmune disease with a complex genetic etiology. Here we identify a SNP in the promoter region of FCRL3, a member of the Fc receptor-like family, that is associated with susceptibility to rheumatoid arthritis (odds ratio = 2.15, P = 0.00000085). This polymorphism alters the binding affinity of nuclear factor-κB and regulates FCRL3 expression. We observed high FCRL3 expression on B cells and augmented autoantibody production in individuals with the disease-susceptible genotype. We also found associations between the SNP and susceptibility to autoimmune thyroid disease and systemic lupus erythematosus. FCRL3 may therefore have a pivotal role in autoimmunity.

Morphological Changes in the Peritoneal Vasculature of Patients on CAPD with Ultrafiltration Failure

Vascular changes in the peritoneum were histochemically assessed in patients on continuous ambulatory peritoneal dialysis (CAPD) with ultrafiltration failure. Light microscopy showed extensive interstitial fibrosis, mesothelial denudation and vascular changes. Morphological changes in the vasculature were observed at different levels. The specific changes in the vasculature in these patients were characterized by severe fibrosis and hyalinization of the media of venules. Immunofluorescence microscopy revealed extensive deposition of such extracellular matrices as type IV collagen and laminin in the vascular wall. Electron microscopy revealed a significant increase in collagenous fibers and degeneration of smooth muscle cells in the media. However, the endothelial cells at the levels of vasculature affected were relatively well preserved. These pathological alterations in the vasculature in CAPD patients with ultrafiltration failure suggest that certain toxic factors, such as a high osmolar dialysate or low pH of dialysate, had affected the peritoneal vasculature from the adventitial side rather than the endothelial side. These vascular changes in the peritoneum are thought to be irreversible, associated with deterioration of peritoneal function, and to cause ultrafiltration failure in the patients on long-term CAPD therapy.

The progression of vascular calcification and serum osteoprotegerin levels in patients on long-term hemodialysis

BACKGROUND The aortic calcification index (ACI), estimated on abdominal computed tomographic scans, has been associated with the extent of arteriosclerosis in hemodialysis patients. However, the contribution of biochemical markers to the progression of vascular calcification in patients undergoing hemodialysis is not fully understood. METHODS We examined the relationship between coronary risk factors; metabolic factors, including serum osteoprotegerin (OPG) concentration; and progression of vascular calcification in 26 dialysis patients. RESULTS Mean patient age was 52.6 +/- 8.7 (SD) years, and mean duration of dialysis therapy was 7.7 +/- 5.8 years. ACI was measured twice in each patient, and the mean interscan period was 4.9 +/- 0.3 years. Mean ACI changed from 22.2 +/- 24.2 to 33.9 +/- 28.8 overall, and mean change in ACI (DeltaACI) was 12.0 +/- 9.9. Patients were divided into 2 groups: slow progressors, with DeltaACI of 4.1 +/- 3.2 (n = 13), and rapid progressors, with DeltaACI of 19.8 +/- 7.9 (n = 13). Serum fasting glucose and CRP levels of rapid progressors were high, and their serum albumin and intact parathyroid hormone levels were low. Multiple regression analyses showed that serum OPG levels were independently associated with vascular calcification in the hemodialysis patients studied. CONCLUSION Rapid progression of vascular calcification was associated with dose of calcium carbonate prescribed and serum OPG concentration. The clinical significance of these observations remains to be determined.

Japan as the front‐runner of super‐aged societies: Perspectives from medicine and medical care in Japan

The demographic structure of a country changes dramatically with increasing trends toward general population aging and declining birth rates. In Japan, the percentage of the elderly population (aged ≥65 years) reached 25% in 2013; it is expected to exceed 30% in 2025 and reach 39.9% in 2060. The national total population has been decreasing steadily since its peak reached in 2008, and it is expected to fall to the order of 80 million in 2060. Of the total population, those aged ≥75 years accounted for 12.3% as of 2013, and this is expected to reach 26.9% in 2060. As the demographic structure changes, the disease structure changes, and therefore the medical care demand changes. To accommodate the medical care demand changes, it is necessary to secure a system for providing medical care. Japan has thus far attained remarkable achievements in medical care, seeking a better prognosis for survival; however, its medical care demand is anticipated to change both qualitatively and quantitatively. As diseases in the elderly, particularly in the old‐old population, are often intractable, conventional medical care must be upgraded to one suitable for an aged society. What is required to this end is a shift from “cure‐seeking medical care” focusing on disease treatment on an organ‐specific basis to “cure and support‐seeking medical care” with treatments reprioritized to maximize the quality of life (QOL) for the patient, or a change from “hospital‐centered medical care” to “community‐oriented medical care” in correlation with nursing care and welfare.

Association of single-nucleotide polymorphisms in the polymeric immunoglobulin receptor gene with immunoglobulin A nephropathy (IgAN) in Japanese patients

AbstractImmunoglobulin A nephropathy (IgAN) is a primary glomerulonephritis of common incidence world-wide whose etiology and pathogenesis remain unresolved, although genetic factors are assumed to be involved in the development and progression of this disease. To identify genetic variations that might confer susceptibility to IgAN, we performed a case-control association study involving 389 Japanese IgAN patients and 465 controls. Genome-wide analysis of approximately 80,000 single-nucleotide polymorphisms (SNPs) identified a significant association between IgAN and six SNPs located in the PIGR (polymeric immuoglobulin receptor) gene at chromosome 1q31-q41. One of them, PIGR-17, caused an amino-acid substitution from alanine to valine at codon 580 (χ2=13.05, P=0.0003, odds ratio [OR] =1.59, 95% confidence interval [95% CI] =1.24–2.05); the OR of minor homozygotes to others was 2.71 (95% CI = 1.31–5.61). Another SNP, PIGR-2, could affect promoter activity (χ2 = 11.95, P=0.00055, OR=1.60, 95% CI=1.22–2.08); the OR of minor homozygotes to others was 2.08 (95% CI=0.94–4.60). Pairwise analyses demonstrated that all six SNPs were in almost complete linkage disequilibrium. Biopsy specimens from IgAN patients were positively stained by antibody against the secretory component of PIGR, but corresponding tissues from non-IgAN patients were not. Our results suggest that a gene associated with susceptibility to IgAN lies within or close to the PIGR gene locus on chromosome 1q in the Japanese population.

Plasma concentration of brain natriuretic peptide as an indicator of cardiac ventricular function in patients on hemodialysis

The plasma concentration of human brain natriuretic peptide (BNP) was measured by immunoradiometric assay in patients on maintenance hemodialysis (HD) to assess the possible relationship between the plasma levels of this peptide and cardiac ventricular function, as judged by M-mode echocardiography. The plasma BNP levels in the pre-HD state were significantly higher (688.5 ± 154.5 pg/ml) than those of healthy subjects (<40 pg/ml). In addition, the plasma BNP levels were slightly decreased during HD (post-HD, 617.3 ± 157.1 pg/ml). There was no correlation between the plasma levels of BNP and body weight changes during HD. The mean plasma BNP level was significantly higher in the group of patients with a low left ventricular ejection fraction (EF < 60%) than in the group with a normal EF. In the patients as a whole, there was an inverse correlation between plasma BNP levels and EF. Moreover, a positive correlation was found between plasma BNP levels and left ventricular mass index (r = 0.57, p < 0.05). These results suggest that plasma BNP levels increase in response to chronic stimulation in accordance with increased cardiac load, and that they may be a possible indicator of reduced ventricular function in HD patients.

Soluble Osteopontin and Vascular Calcification in Hemodialysis Patients

Background: Vascular calcification often occurs in patients with uremia. As osteopontin (OPN) is not only involved in the physiological but also the pathological calcification of tissues, OPN may be associated with the pathogenesis of aortic calcification in hemodialysis (HD) patients. Methods: We examined the expression of OPN in atherosclerotic aortas of HD patients. In addition, we performed a prospective longitudinal study by using CT scans to detect aortic calcifications and by measuring the plasma OPN concentration by ELISA in HD patients (20 men, 16 women; mean age 55.2 ± 21.3 years) and in healthy volunteers (18 men, 17 women; mean age 54.0 ± 13.2 years). Results: By immunohistochemical staining, OPN was abundantly localized in atherosclerotic plaques of HD patients. The macrophages surrounding the atheromatous plaques were identified as the OPN-expressing cells. We furthermore found that the concentration of soluble plasma OPN was significantly higher in HD patients as compared with the concentrations in age-matched healthy volunteers (837.3 ± 443.2 vs. 315.1 ± 117.4 ng/ml, p < 0.01). The OPN concentration was positively correlated with the aortic calcification index in HD patients (r = 0.749, p < 0.01). Conclusion: These data suggest that OPN, secreted by macrophages, plays a role in the calcification of atheromatous plaques in HD patients.

Effects of long-term treatment with mizoribine in patients with proliferative lupus nephritis.

AIM Mizoribine (MZR) is a purine antimetabolic immunosuppressant agent that has few little severe adverse events. We studied whether maintenance therapy with MZR and prednisolone (PSL) in severe proliferative lupus nephritis patients could improve immunity, reduce proteinuria, prevent renal relapse, and reduce steroid dose. METHOD Long-term maintenance therapy with MZR and PSL was evaluated in ten patients with biopsy-proven proliferative lupus nephritis. Patients with severe lupus nephritis, who had proteinuria of 0.5 g or more even after treatments with plasma exchange and/or pulse methyl prednisolone, were recruited. MZR at an average dose of 140 +/- 10 (100 - 200) mg was administered two to three times/day in combination with PSL. The average period for the MZR maintenance therapy was 89.7 +/- 5.5 (70 - 126) months. Urine protein excretion, serum hemolytic complement activity (CH50), C3, serum creatinine, general and biochemical blood examinations, anti-ds-DNA antibody were collected at each monthly medical examination. RESULTS All patients were females, mean age 43.0 +/- 3.3 years. A significant decrease in proteinuria was noted two years after the combination therapy (p = 0.0016). Five patients experienced lupus nephritis relapse. Patients who did not experience relapses had their MZR combination therapy initiated earlier (p = 0.037) when compared with the patients who experienced relapses. Serum creatinine levels remained unchanged in all patients throughout treatment and follow-up, even during renal relapses. Levels of C3 and CH50 normalized as proteinuria decreased. None of the patients developed serious side effects during MZR treatment. A significant steroid-sparing effect was observed three years after initiating MZR (p = 0.0025). CONCLUSION From our long-term observation, maintenance therapy with low-dose PSL combined with MZR can eliminate proteinuria and have steroid-sparing effect. Early initiation of the therapy can protect against renal relapses among severe proliferative lupus nephritis patients without serious side effects.

Latent IgA deposition from donor kidney is the major risk factor for recurrent IgA nephropathy in renal transplantation

Abstract:  Background:  Previous studies have recognized risk factors for recurrent IgA nephropathy (r‐IgAN) in renal transplantation. However the clinical significance of latent IgA deposition from the donor kidney remains to be determined.

Single-nucleotide polymorphisms in the class II region of the major histocompatibility complex in Japanese patients with immunoglobulin A nephropathy

AbstractImmunoglobulin A nephropathy (IgAN) is a form of chronic glomerulonephritis of unknown etiology and pathogenesis. Immunogenetic studies have not conclusively indicated that human leukocyte antigen (HLA) is involved. As a first step in investigating a possible relationship between HLA class II genes and IgAN, we analyzed the extent of linkage disequilibrium (LD) in this region of chromosome 6p21.3 in a Japanese test population and found extended LD blocks within the class II locus. We designed a case-control association study of single-nucleotide polymorphisms (SNPs) in each of those LD blocks, and determined that SNPs located in the HLA-DRA gene were significantly associated with an increased risk of IgAN (P = 0.000001, odds ratio = 1.91 [95% confidence interval 1.46–2.49]); SNPs in other LD blocks were not. Our data imply that some haplotype of the HLA-DRA locus has an important role in the development of IgAN in Japanese patients.