Yasuhiko Kanazawa

Keio University, Edo, Tōkyō, Japan

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Publications (15)73.98 Total impact

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    ABSTRACT: Most type 1 diabetes mellitus is caused by autoimmune pancreatic beta-cell destruction. Several antigens such as insulin, glutamic acid decarboxylase (GAD) and islet-specific glucose-6-phosphatase catalytic subunit related protein (IGRP) are considered to take part in the autoimmune destructive process. Because the role of GAD in the disease process of type 1 diabetes is still controversial, we investigated the disease phenotype upon in vivo induction of whole GAD65 reactivity using a GAD65 homo knockout NOD splenocytes to NOD-scid transfer system. Splenocytes from 8 to 10-week-old female GAD65 homo knockout (=KOT splenocytes) or age-matched wild type (=WTT splenocytes) NOD mice were transferred into female NOD-scid recipients. As compared to recipients of WTT splenocytes, the onset of diabetes in recipients of KOT splenocytes was significantly delayed (p<0.001). Moreover, TGF-beta expression was enhanced in the pancreas from recipients of KOT splenocytes. Splenocytes from recipients of KOT splenocytes produced IL-10 (/IFN-gamma) upon GAD65 stimulation, whereas those from recipients of WTT splenocytes did not. Based upon these results, we propose that anti-whole GAD65-reactive T cells have the ability to regulate the development of type 1 diabetes.
    Journal of Autoimmunity 03/2009; 32(2):104-9. DOI:10.1016/j.jaut.2009.01.001 · 7.02 Impact Factor
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    ABSTRACT: The IL-2 receptor-alpha (IL2RA), also known as CD25, is expressed on the regulatory T cells, which play an important role in the control of immune responses and the maintenance of immune homeostasis. Our objective was to determine whether variants in the IL2RA gene are associated with type 1 diabetes in the Japanese population. We genotyped the four single-nucleotide polymorphisms (rs706778, rs3118470, ss52580101, and rs11594656) of the IL2RA in 885 patients with type 1 diabetes and 606 control subjects of Japanese origin. The allele and genotype frequencies were examined in the patient groups stratified by their mode of onset in a case-control study. We found evidence of association with acute-onset, but not slow-onset and fulminant, type 1 diabetes for two of the four single-nucleotide polymorphisms genotyped (rs706778 and rs3118470). The rs706778 A allele and the rs3118470 G allele were associated with an increased disease risk [odds ratio (OR) for rs706778 AA genotype 1.54, P = 4.2 x 10(-4) and OR for rs3118470 GG genotype 1.50, P = 0.0019, respectively]. Furthermore, the A-G haplotype was associated with increased type 1 diabetes risk in the acute-onset form (OR 1.30, P = 0.002). The present data confirm the type 1 diabetes association with IL2RA and provide evidence that the different contributions of the IL2RA in the susceptibility to acute-onset and other forms of type 1 diabetes in the Japanese population.
    The Journal of Clinical Endocrinology and Metabolism 03/2009; 94(3):947-52. DOI:10.1210/jc.2008-1596 · 6.31 Impact Factor
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    ABSTRACT: Some reports have shown that the cause of type 1 diabetes is associated with dysfunction of regulatory T cells (Tregs). The FOXP3/Scurfin gene is known to be a master gene of Tregs. Therefore, we tried to analyze the relation between the gene polymorphism and adult onset type 1 diabetes and its subtype in the Japanese population. In this study, we recruited 316 Japanese patients with type 1 diabetes (155 male and 161 female, mean onset age 35.4 years) and 432 healthy Japanese controls (263 male and 169 female, mean age 44.4 years). Then we subdivided the patients by onset type, sex, and islet-associated autoantibody positivity. The genotype frequency of (GT)(16)/(GT)(16) in female patients with overall type 1 diabetes was especially lower than that in controls (19.9% vs. 38.5%, p = 0.0002). Moreover, the genotype frequency of (GT)(16)/(GT)(16) in female patients with slowly progressive type 1 diabetes was significantly lower than that in controls (15.4% vs. 38.5%, p = 0.002). Our data showed that the (GT)n microsatelloite polymorphism in the FOXP3/Scrufin gene was associated with Japanese adult onset type 1 diabetes, especially in females, and slowly progressive type 1 diabetes.
    Autoimmunity 01/2009; 42(2):159-67. DOI:10.1080/08916930802488258 · 2.75 Impact Factor
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    ABSTRACT: Recent genome-wide association studies have identified several novel type 1 diabetes (T1D) loci in white populations. Objective: In line with recent findings, we conducted a replication study of two loci on chromosome 12p13 and 16p13 and assessed their potential associations with thyroid autoimmunity in a Japanese population. Two single-nucleotide polymorphisms (SNPs), rs2292399 in ERBB3 on 12q13 and rs2903692 in CLEC16A (or KIAA0350) on 16p13, were analyzed in Japanese subjects consisting of 735 T1D patients, 330 patients with autoimmune thyroid disease (AITD), and 621 control subjects. According to a case-control study and logistic regression adjusting for sex and age, we observed that these SNPs in ERBB3 and CLEC16A were both significantly associated with T1D, with the risk alleles being consistent with those in white populations [adjusting odds ratio by multiplicative model: 1.37 (1.13-1.67), P = 0.001; and 1.28 (1.02-1.60), P = 0.030, respectively]. In both SNPs, the association was suggested to be stronger in T1D complicated with AITD (Graves' disease, Hashimoto's thyroiditis, or thyroid autoantibodies). Furthermore, a joint analysis, with the INS and CTLA4 SNPs, revealed that CTLA4 rs3087243, ERBB3 rs2292399, and CLEC16A rs2903692, but not INS rs689, were significant risk factors for the cooccurrence of AITD in Japanese T1D. We confirmed two loci on 12q13 and 16p13 that were identified by the independent genome-wide association studies in white populations, thus suggesting that these loci contribute to T1D susceptibility across different ethnic groups. In addition, these loci may also be associated with the cooccurrence of thyroid autoimmunity in T1D.
    Journal of Clinical Endocrinology &amp Metabolism 11/2008; 94(1):231-5. DOI:10.1210/jc.2008-0718 · 6.31 Impact Factor
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    ABSTRACT: Type 1 diabetes is considered to be T-helper 1 (Th1) type autoimmune disease. Because the vitamin D receptor is expressed on CD4+T cells and is known to affect cytokine responses, several groups have investigated the association between the vitamin D receptor gene BsmI polymorphism and type 1 diabetes. However, this issue is still controversial; therefore, we examined this gene polymorphism in a large number of type 1 diabetic patients as a multi-center collaborative study in Japan. A total of 1,373 subjects, including 774 cases and 599 control subjects of Japanese origin, were studied. The frequency of carriers of the BB genotype in type 1 diabetic patients was significantly higher than that in controls (p<0.01, odds ratio 3.65). Moreover, IFN-gamma production upon anti-CD3 stimulation in the BB genotype group was significantly higher than that in the Bb and bb genotype groups (p<0.05), suggesting that the polyclonal T cell response in BB genotype patients is Th1 dominant. Based upon these results, we propose that it may be worthwhile to focus on subjects with the BB genotype of this gene polymorphism as having high risk for type 1 diabetes.
    Journal of Autoimmunity 06/2008; 30(4):207-11. DOI:10.1016/j.jaut.2007.09.002 · 7.02 Impact Factor
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    ABSTRACT: At the onset of type 1 diabetes, most of the insulin-producing pancreatic beta cells are destroyed by effector cells, and therefore, the following two factors, at a minimum, are necessary for "reversing" hyperglycemia in autoimmune diabetes; depletion of effector cells and enhancement of beta cell regeneration. In this study, we tried a novel approach for "reversing" autoimmune diabetes in a murine model. Here we show that remission could be achieved with a combination therapy of a single injection of complete Freund's adjuvant (CFA) and a single intraperitoneal injection of a pancreatic beta cell line, MIN6N-9a, in recent-onset diabetic NOD (non-obese diabetic) mice. Five out of seven mice (71%) receiving MIN6N-9a and CFA became normoglycemic within 120 days after treatment, whereas only two of nine (22%) receiving vehicle instead of MIN6N-9a achieved remission. Histological examination of pancreatic specimens from "reversed" mice showed decreased islet number, but each islet was markedly hyperplastic; being about six times larger than those from controls. Although it has been reported that hematopoietic cells such as splenocytes differentiate into insulin-producing cells and play a key role, our data indicate that they are not an absolute requirement for the "reversal" of autoimmune diabetes.
    Diabetes research and clinical practice 02/2008; 79(1):18-23. DOI:10.1016/j.diabres.2007.08.020 · 2.54 Impact Factor
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    American Journal of Medical Genetics Part A 08/2007; 143A(15):1812-1813. DOI:10.1002/ajmg.a.31833 · 2.05 Impact Factor
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    ABSTRACT: It is suggested that insulin autoimmunity plays an important role in the development of type 1 diabetes in humans. However, the association between insulin gene (INS) region (IDDM2) and type 1 diabetes has been uncertain in Asians. A multicenter collaboration study was conducted to clarify the role of the IDDM2 region in Japan. In total, 661 patients with type 1 diabetes and 706 control subjects were enrolled. The INS variable number of tandem repeat (VNTR) class I/class III status was estimated by genotyping the -23 HphI single nucleotide polymorphism. From surrounding polymorphisms across the insulin gene, we also inferred haplotypes bearing INS VNTR lineages. The frequency of the class I allele was 99.3% in patients and 96.7% in controls (P < 10(-5)), and the class I/III or III/III genotype was found in 1.4% of patients and in 6.4% of controls [odds ratio (OR) 0.20, P < 10(-5)]. The class I subdivision revealed IC to increase significantly in patients with type 1 diabetes (P = 0.002), whereas ID did not; the distribution of IC and ID was significantly different between patients and controls (P = 0.014). The present study certainly shows that the IDDM2 region is also a susceptibility locus in the Japanese population. Furthermore, it was revealed that IC may be more susceptible to type 1 diabetes than ID, which could be evidence that the INS VNTR itself confers susceptibility to type 1 diabetes.
    Journal of Clinical Endocrinology &amp Metabolism 05/2007; 92(5):1791-5. DOI:10.1210/jc.2006-2242 · 6.31 Impact Factor
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    ABSTRACT: One of the CTLA-4 SNPs, +6230G>A (CT60), has recently been reported to be related to susceptibility to type 1 diabetes and autoimmune thyroid disease. We have previously reported an association between acute-onset type 1 diabetes in Japanese and the Vitamin D receptor (VDR) gene Bsm I large B polymorphism, which is related to the Th1-type response. Moreover, we found a significant correlation between autoimmune-related type 1 diabetes with HLA DR9 and detection of GAD-reactive Th1 (T helper 1)-type cells. In the present article, we tried to clarify whether the frequency of one of the CTLA-4 SNPs, +6230G>A (CT60), is affected by the VDR gene Bsm I polymorphism or by HLA DR9 in Japanese type 1 diabetics. The frequency of the CT60 GG genotype did not appear to be affected by either the VDR gene Bsm I large B polymorphism or HLA DR9.
    Annals of the New York Academy of Sciences 11/2006; 1079(1):251-6. DOI:10.1196/annals.1375.038 · 4.31 Impact Factor
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    ABSTRACT: Thiazolidinediones improve glycemic control by reducing insulin resistance. Some studies have demonstrated that troglitazone had a preventative effect on diabetes in NOD (non-obese diabetic) mice. One of the mechanisms proposed for the prevention of diabetes by thiazolidinediones is an effect on T-helper 1/T-helper 2 (Th1/Th2) balance. In this article, we attempted to clarify whether pioglitazone is also effective in preventing diabetes as compared to metformin, which has no immunological effect. Female NOD mice were administered pioglitazone or metformin orally, and the insulitis score, cytokines secreted from splenocytes, cytokine expression levels in the pancreas, and the incidence of diabetes after acceleration by cyclophosphamide were analyzed. We could not find any advantage of pioglitazone in preventing Th1 skewing and the development of diabetes over metformin. Therefore, further research should take place before the application of thiazolidinediones to human slowly progressive insulin-dependent diabetes mellitus (SPIDDM) patients.
    Annals of the New York Academy of Sciences 11/2006; 1079(1):365-8. DOI:10.1196/annals.1375.056 · 4.31 Impact Factor
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    ABSTRACT: The protein tyrosine phosphatase, nonreceptor 22 gene (PTPN22) maps to human chromosome 1p13.3-p13.1 and encodes an important negative regulator of T-cell activation, lymphoid-specific phosphatase (Lyp). Recently, the minor allele of a single-nucleotide polymorphism (SNP) at nucleotide position 1858 (rs2476601, +1858C > T) was found to be associated with type 1 diabetes. However, the degree of the association is variable among ethnic populations, suggesting the presence of other disease-associated variants in PTPN22. To examine this possibility, we carried out a systemic search for PTPN22 using direct sequencing of PCR-amplified products in the Japanese population. Association and linkage studies were also conducted in 1,690 Japanese samples, 180 Korean samples, and 472 Caucasian samples from 95 nuclear families. We identified five novel SNPs, but not the +1858C > T SNP. Of these two frequent SNPs, -1123G > C, and +2740C > T were in strong linkage disequilibrium (LD), and the -1123G > C promoter SNP was associated with acute-onset but not slow-onset type 1 diabetes in the Japanese population (odds ratio [OR] = 1.42, 95% CI = 1.07-1.89, P = 0.015). This association was observed also in Korean patients with type 1 diabetes (Mantel-Haenszel chi2= 6.543, P = 0.0105, combined OR = 1.41 95% CI = 1.09-1.82). Furthermore, the affected family-based control (AFBAC) association test and the transmission disequilibrium analysis of multiplex families of European descent from the British Diabetes Association (BDA) Warren Repository indicated that the association was stronger in -1123G > C compared to +1858C > T. In conclusion, the type 1 diabetes association with PTPN22 is confirmed, but it cannot be attributed solely to the +1858C > T variant. The promoter -1123G > C SNP is a more likely causative variant in PTPN22.
    American Journal of Medical Genetics Part A 03/2006; 140(6):586-93. DOI:10.1002/ajmg.a.31124 · 2.05 Impact Factor
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    ABSTRACT: Although we have previously reported an elevated serum level of CXCL10/IP-10 (CXCL10), a Th1 chemokine, in type 1 diabetic patients, little is known about the origin of serum CXCL10 and its significance in type 1 diabetes. Therefore, we examined serum CXCL10 level in NOD mice in association with the expression level of CXCL10 in the pancreas, pancreatic lymph nodes (LN) and spleen. Serum CXCL10 level increased over time towards the onset of diabetes, and was significantly higher in the "diabetic" period (20 and 24 weeks of age and at onset of diabetes) than in the "pre-diabetic" period (4, 8 and 16 weeks of age). Moreover, serum CXCL10 level was associated with CXCL10 and CXCR3 mRNA level in pancreatic LN. Furthermore, it seemed that serum CXCL10 level increased just before (or at) the onset of overt diabetes. These results suggest that serum CXCL10 level may reflect accumulation of Th1 lymphocytes in pancreatic LN, and measurement of serum CXCL10 level may be useful to assess the pathophysiology of the disease course in type 1 diabetes.
    Journal of Autoimmunity 03/2006; 26(1):66-71. DOI:10.1016/j.jaut.2005.09.027 · 7.02 Impact Factor
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    ABSTRACT: Transracial studies are a powerful tool for genetic association studies of multifactorial diseases, such as type 1 diabetes. The low incidence of type 1 diabetes in Asian countries, however, makes it difficult to perform large-scale studies in Asia. To overcome this, we have assembled a multicenter study group in Japan and studied the association of CTLA4 polymorphisms with type 1 diabetes relative to autoimmune thyroid disease (AITD) phenotypes. Subjects included a total of 1837 samples, including 1114 cases (769 with type 1 diabetes and 345 with AITD) and 723 control subjects. The +6230G>A and +49G>A polymorphisms of CTLA4 as well as HLA-DRB1 and -DQB1 were genotyped. The +6230G>A polymorphism was significantly associated with type 1 diabetes complicated with AITD (odds ratio, 1.54; P = 0.027) and with AITD alone (odds ratio, 1.31; P = 0.045) but not with type 1 diabetes without AITD. The association with type 1 diabetes positive for autoantibodies to both pancreatic islets and thyroid was particularly strong (odds ratio, 1.87; P = 0.001). Type 1 diabetic patients with the disease-associated GG genotype were characterized by a significantly higher frequency of AITD (P = 0.013), of positivity for both AITD and antiislet autoantibody (P = 0.00086), and of high-risk HLA genotypes (P = 0.034). Given the high frequency of AITD in patients with type 1 diabetes, these data suggest the possibility that the association of CTLA4 with type 1 diabetes in previous studies may have been secondary to AITD, suggesting the importance of subclassification of type 1 diabetes relative to AITD in genetic studies.
    Journal of Clinical Endocrinology &amp Metabolism 03/2006; 91(3):1087-92. DOI:10.1210/jc.2005-1407 · 6.31 Impact Factor
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    ABSTRACT: CXCL10, a chemokine for Th1 cells, is involved in the pathogenesis of various Th1-dominant autoimmune diseases. Type 1 diabetes is considered to be a Th1-dominant autoimmune disease, and a suppressive effect of CXCL10 neutralization on diabetes development has been reported in a cyclophosphamide-induced accelerated diabetes model through induction of beta cell proliferation. However, intervention in a diabetes model might bring about opposite effects, depending on the timing, amount, or method of treatment. In the present study, we examined the effect of CXCL10 neutralization in a "spontaneous diabetes" model of NOD mice, using CXCL10 DNA vaccination (pCAGGS-CXCL10). pCAGGS-CXCL10 treatment in young NOD mice induced the production of anti-CXCL10 Ab in vivo and suppressed the incidence of spontaneous diabetes, although this treatment did not inhibit insulitis or alter the immunological response. pCAGGS-CXCL10 treatment enhanced the proliferation of pancreatic beta cells, resulting in an increase of beta cell mass in this spontaneous diabetes model as well. Therefore, CXCL10 neutralization is suggested to be useful for maintaining beta cell mass at any stage of autoimmune diabetes.
    The Journal of Immunology 01/2006; 175(12):8401-8. DOI:10.4049/jimmunol.175.12.8401 · 5.36 Impact Factor
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    ABSTRACT: Type 1 diabetes mellitus (T1DM) is considered to be a T cell-mediated disease, and many reports suggest that some HLA types, especially HLA DR4 and DR9, convey susceptibility to T1DM in Japanese. We investigated the association between T cell reactivity against GAD and HLA types in "islet-associated autoantibody-positive" T1DM in Japanese. Blood samples were obtained from 36 "autoantibody-positive" type 1 diabetic patients with HLA DR4 or DR9 and 23 type 2 diabetic patients with HLA DR4 or DR9 as controls. They were divided into three groups, DR4/9, DR4/X, and DR9/X groups. In each HLA type group, GAD-reactive IFN-gamma-producing CD4(+) cells were assessed by means of intracellular cytokine staining for flow cytometry. Type 1 diabetic patients with HLA DR9/X had significantly higher numbers of GAD-reactive IFN-gamma-producing CD4(+) cells as compared to type 1 diabetic patients with DR4/X or DR4/9 (P < 0.05) and all type 2 diabetic patients. There was no significant difference in the number of GAD-reactive IFN-gamma-producing CD4(+) cells between type 1 diabetic and type 2 diabetic patients belonging to the DR4/X and DR4/9 groups. There was an association between T cell reactivity against GAD and HLA DR9 in Japanese type 1 diabetes.
    Annals of the New York Academy of Sciences 12/2004; 1037(1):33-40. DOI:10.1196/annals.1337.006 · 4.31 Impact Factor