Association of the polymorphism in manganese superoxide dismutase gene with diabetic retinopathy in Chinese type 2 diabetic patients

OBJECTIVE: To investigate the association of the polymorphism in manganese superoxide dismutase (Mn-SOD) gene in Chinese type 2 diabetic patients with diabetic retinopathy. METHODS: The Ala(-9)Val polymorphism of the Mn-SOD gene was determined by polymerase chain reaction and direct sequencing in 198 normal control subjects and 264 patients with type 2 diabetes mellitus, among them there were 139 non-diabetic retinopathy (NDR) subjects and 125 subjects with diabetic retinopathy (DR). RESULTS: There was no statistic difference in the frequencies of VV genotype and V allele between the type 2 diabetic group and the control group. However, the frequencies of VV genotype and V allele were significantly higher in the DR group than that in the NDR group (chi-square (2)=5.015, P=0.025?chi-square (2)=10.253, P=0.001),but there was no statistic difference in the NDR group compared with the control group (P > 0.05). The presence of V allele was shown to be associated with diabetic retinopathy (OR=1.96, 95%CI: 1.29-2.97). Furthermore, the subjects carrying the VV genotype had lower serum Mn-SOD level (P=0.025) and had a tendency of higher total serum SOD activity, but this tendency had no statistic significance. CONCLUSION: The Ala(-9)Val polymorphism in the Mn-SOD gene may not be related to the etiology of type 2 diabetes, but it seems to contribute to the development of diabetic retinopathy in Chinese type 2 diabetic patients.     

锰超氧化物歧化酶基因Ala(-9)Val多态性与2型糖尿病视网膜病变的相关性

目的 探讨锰超氧化物歧化酶(manganese superoxide dismutase,Mn-SOD)基因Ala(-9)Val多态性与2型糖尿病视网膜病变发生的关联性.方法 应用PCR-直接测序方法检测了中国湖北地区汉族264例2型糖尿病患者和198名正常对照者的Mn-SOD基因Ala(-9)Val多态性(GCT→GTT).结果 (1)2型糖尿病组与正常对照组比较,VV基因型频率(72.7%vs 67.2%,P>0.05)与V等位基因频率(76.1%vs71.0%,P>0.05)差异无统计学意义.(2)在2型糖尿病者中,有糖尿病视网膜病变(diabetic retinopathy,DR)组 VV基因型频率为79.2%,与无糖尿病视网膜病变(non-diabetic retinopathy,NDR)组(66.9%)比较,差异有统计学意义(x2=5.015,P=0.025);V等位基因频率在DR组为82.4%,NDR组为70.5%,差异亦有统计学意义(x2=10.253,P=0.001);NDR组与正常对照组比较,VV基因型频率(66.9%vs67.2%,P>0.05)及V等位基因频率(70.5%vs 71.0%,P>0.05)差异无统计学意义,V等位基因与2型糖尿病视网膜病发生相关(OR=1.96,95%CI:1.29-2.97).(3)基因型为VV型的2型糖尿病患者其Nn-SOD水平较AA型、AV型患者低,差异有统计学意义(P=0.025),其总超氧化物歧化酶有增加趋势,但差异无统计学意义(P>0.05).结论 Mn-SOD基因Ala(-9)Val多态性与2型糖尿病发病无关,但可能参与了2型糖尿病视网膜病变的发生、发展过程.     

The polymorphism of manganese superoxide dismutase is associated with diabetic nephropathy in Japanese type 2 diabetic patients

 We evaluated the relationship of an alanine or valine polymorphism at amino acid sequence 16 [Val(16)Ala] of manganese superoxide dismutase (Mn-SOD) with diabetes and diabetic nephropathy in Japanese type 2 diabetic patients. Val(16)Ala genotyping of Mn-SOD was done by polymerase chain reaction-restriction fragment length polymorphism with a restriction enzyme (Bsaw I) in 478 Japanese type 2 diabetic patients and 261 nondiabetic Japanese healthy subjects. The genotype distribution of diabetic and nondiabetic subjects was then compared, and the association of genotype with diabetic nephropathy was evaluated in the diabetic patients. The allele frequency and genotype of the diabetic patients were not different from those of the healthy nondiabetic subjects. The VV type showed a significantly higher frequency in the diabetic patients with nephropathy than did the AA or VA type [VV type: normoalbuminuria 70.8%, microalbuminuria 84.8% (P = 0.0057), macroalbuminuria 84.1% (P = 0.0128)]. Furthermore, logistic regression analysis showed that this polymorphism is associated with diabetic nephropathy independently (odds ratio = 0.461925, P = 0.03). Accordingly, the Val(16)Ala polymorphism of Mn-SOD may be unrelated to the etiology of type 2 diabetes, but it seems to be associated with diabetic nephropathy in Japanese type 2 diabetic patients. Received: August 5, 2002 / Accepted: December 3, 2002 Correspondence to:Y. Tanaka     

<Emphasis Type="Italic">Bgl</Emphasis>II gene polymorphism of the α2β1 integrin gene is a risk factor for diabetic retinopathy in Caucasians with type 2 diabetes

Platelets are thought to be involved in the pathogenesis of diabetic retinopathy. The BglII gene polymorphism of the 21 integrin, which is a platelet collagen receptor, has been suggested as a genetic risk factor for diabetic retinopathy in Japanese subjects. The aim of this study was to look for a relationship between the BglII gene polymorphism of the 21 integrin gene and the development of diabetic retinopathy in Caucasians with type 2 diabetes. Subjects with type 2 diabetes and diabetic retinopathy (n=163) were compared with diabetic subjects without diabetic retinopathy (n=95). A significantly higher frequency of the BglII (+/+) genotype of the gene polymorphism of the 21 integrin gene was found in patients with diabetic retinopathy compared with patients without diabetic retinopathy (19.6% vs 7.4%; P=0.008). The present study demonstrates that the BglII (+/+) genotype of the gene polymorphism of the 21 integrin gene is an independent risk factor (odds ratio: 2.4, 95% confidence interval 1.0–6.0; P<0.05) for diabetic retinopathy in Caucasians with type 2 diabetes.     

糖尿病视网膜病MTHFR基因多态性及其与血浆同型半胱氨酸水平的关系

目的：研究亚甲基四氢叶酸还原酶（methylenetetrahydrofolate reductase,MTHFR）基因多态性及血浆同型半胱氨酸水平与2型糖尿病视网膜病的关系。方法：应用聚合酶链反应－限制性内切酶片段长度多态性技术检测208例2型糖尿病患者（其中110例伴视网膜病）及57名正常对照的MTHFR C677T基因型，采用高效液相色谱法测定血浆同型半胱氨酸水平。结果：糖尿病视网膜病组MTHFR基因TT纯合基因型、CT杂合基因型及T等位基因频率（分别为28．18％、41．82％、49．09％）均明显高于糖尿病不伴视网膜病组（分别为18．37％、29．59％、33．16％）及正常对照组（分别为17．54％、28．07％、31．58％），基因型和等位基因频率分布差异均有显著性（P＜0．01），而MTHFR基因多态性在糖尿病不伴视网膜病组与正常对照组之间差异无显著性（P＞0．05），T等位基因与糖尿病视网膜病的发生密切相关（OR＝1．94，95％CI；1．31－2．88）。糖尿病视网膜病组、糖尿病不伴视网膜病组及正常对照组中，MTHFR基因有C677T突变者血浆同型半胱氨酸水平均显著高于无基因突变者。结论：MTHFR基因C677T位碱基突变致血浆同型半胱氨酸水平升高可能是糖尿病视网膜病发病的重要遗传因素。     

The -106CC genotype of the aldose reductase gene is associated with an increased risk of proliferative diabetic retinopathy in Caucasian-Brazilians with type 2 diabetes

Diabetic retinopathy is a sight-threatening chronic complication of diabetes mellitus and is the leading cause of acquired blindness in adults. The -106C>T polymorphism in the promoter region of the aldose reductase (AR) gene has been shown to be associated with the susceptibility to diabetic nephropathy in type 2 diabetes, but the findings regarding the occurrence of diabetic retinopathy are conflicting. In this case-control study, we investigated whether the -106C>T polymorphism in the AR gene is involved in the development and progression of diabetic retinopathy in 579 Brazilians with type 2 diabetes (424 Caucasian- and 155 African-Brazilians). Patients underwent a clinical and laboratory evaluation consisting of a questionnaire, physical examination, assessment of diabetic complications and laboratory tests. Genotype analysis was performed using the polymerase chain reaction followed by digestion with restriction enzyme. Logistic regression analysis was used to control for independent risk factors associated with diabetic retinopathy. There were no differences in either genotype or allele frequencies for the -106C>T polymorphism between type 2 diabetic patients with or without diabetic retinopathy, in both ethnic groups. However, the CC genotype was associated with an increased risk of having proliferative diabetic retinopathy in Caucasian-Brazilians with type 2 diabetes (odds ratio (OR)=2.04; 95% confidence interval (CI)=1.21-3.45; P=0.007), independently of other risk factors associated with this complication. Thus, our results show that the -106CC genotype (-106C>T polymorphism) in the AR gene is related to the progression of diabetic retinopathy in Caucasian-Brazilians with type 2 diabetes.     

The catalase -262C/T promoter polymorphism and diabetic complications in Caucasians with type 2 diabetes

Catalase is a central antioxidant enzyme constituting the primary defense against oxidative stress. In this study, we investigated whether the functional -262C/T polymorphism in the promoter of catalase gene is associated with the presence of diabetic retinopathy (DR), diabetic nephropathy (DN) and ischemic heart disease (IHD) in 520 Caucasian-Brazilians with type 2 diabetes. The -262C/T polymorphism was also examined in 100 Caucasian blood donors. Patients underwent a clinical and laboratory evaluation consisting of a questionnaire, physical examination, assessment of diabetic complications and laboratory tests. Genotype analysis was performed using the polymerase chain reaction followed by digestion with restriction enzyme. The genotype and allele frequencies of the -262C/T polymorphism in patients with type 2 diabetes were very similar to those of blood donors (T allele frequency=0.20 and 0.18, respectively). Likewise, there were no differences in either genotype or allele frequencies between type 2 diabetic patients with or without DR, DN or IHD. Thus, our results do not support the hypothesis that the -262C/T polymorphism is related to the development of DR, DN or IHD in patients with type 2 diabetes. Further studies are necessary to elucidate the role of catalase gene polymorphisms in the pathogenesis of diabetic complications.     

血管内皮生长因子3’非翻译区936C/T 突变与糖尿病视网膜病变的关系

目的: 探讨血管内皮生长因子(VEGF)936C/T突变与糖尿病视网膜病变(DR)的关系。方法: 按WHO的糖尿病(DM)诊断和排除标准及分型标准,选取无亲缘关系的2型糖尿病患者254例,分为非增殖性视网膜病变(NPDR)组、增殖性视网膜病变(PDR)组和单纯2型糖尿病(DM)组,选取健康体检人群120例作为正常对照组(NC)。采用PCR-RFLP方法确定全部人员的基因型,对不同组间的临床与生化指标及VEGF浓度、936C/T多态性进行了统计分析。结果: NPDR 和PDR组的CC基因型频率及C等位基因频率显著高于DM组(²=7.490,²=4.448, P<0.05;²=8.333,²=5.227,P<0.05)和NC组(²=9.934,²=4.899, P<0.05; ²=10.895,²=5.714, P<0.05),而NPDR 和PDR组(CT+TT)基因型频率及T等位基因频率显著低于NC组(²=9.934,²=10.895, P<0.01;²=4.899,²=5.714, P<0.05)和DM组(²=7.490,²=8.333,P<0.01;²=4.448,²=5.227,P<0.05)。DR多重危险因素分析显示血清低密度脂蛋白胆固醇(LDL-C)、总胆固醇(TC)、糖化血红蛋白(HbA1c)水平以及VEGF浓度和DR发病呈正相关,而VEGF 936C/T突变与DR发病危险呈负相关(β=-1.027,OR=0.343,P<0.01,CI:0.157-0.723)。结论: 中国汉族人群中存在VEGF 936C/T突变。VEGF 936C等位基因及CC基因型可能是中国汉族糖尿病患者易于发生DR的危险性遗传标志,而VEGF 936T等位基因和携带T等位基因的基因型(936TT基因型和936CT基因型)可能是DR发病风险降低的遗传标志。血浆VEGF、 LDL-C、TC和HbA1c水平可能是2型糖尿病患者易发DR的危险因素。     

Intron 4 polymorphism of the endothelial nitric oxide synthase eNOS gene and early microangiopathy in type 1 diabetes

Nitric oxide (NO) is an endogenous vasodilator involved in inflammatory and autoimmune response, and in the pathophysiology of diabetic vascular disease. Endothelium‐derived NO is formed from l ‐arginine by endothelial NO synthase (eNOS), and earlier studies have provided evidence for altered NO metabolism and impaired endothelial function in diabetes, probably due to polymorphisms in eNOS gene. In the present study we investigated the association of the eNOS gene intron 4 a/b VNTR polymorphism with diabetic microangiopathy in 61 young individuals with type 1 diabetes (T1D), 35 male and 26 female, aged 5.0–29.1 (mean 15.6) years, and followed up for 3.24–11.4 (mean 7.44) years. Ten patients (16.4%) had developed microalbuminuria, three hypertension and two retinopathy. Wild‐type b/b homozygosity for eNOS gene intron 4 VNTR was found in 37 (60.7%) and a/b polymorphism in 24 (39.3%). No significant relationship was demonstrated between eNOS gene intron 4 polymorphisms and microalbuminuria, hypertension or retinopathy in these young individuals. Our findings suggest that a/b polymorphism of the intron 4 eNOS gene is not associated with early onset diabetic microangiopathy.     

GSTT1 null genotype is a risk factor for diabetic retinopathy in Caucasians with type 2 diabetes, whereas GSTM1 null genotype might confer protection against retinopathy

Aim: Substantial data indicate that oxidative stress is involved in the development of diabetic retinopathy (DR). The aim of the present study was to investigate whether the genetic polymorphisms: polymorphic deletions of glutathione S-transferases M1 (GSTM1) and T1 (GSTT1) and Ile105Val of the GSTP1 are associated with DR in Slovenian patients with type 2 diabetes.Methods: In this cross sectional case-control study 604 unrelated Slovene subjects (Caucasians) with type 2 diabetes mellitus were enrolled: 284 patients with DR (cases) and the control group of 320 subjects with type 2 diabetes of more than 10 years’ duration who had no clinical signs of DR. Genotypes were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Results: In our study, the deletion of the GSTM1 was found less frequent in cases with DR than in the controls (27.5% versus 44.4%; P < 0.001), whereas the deletion of GSTT1 was found significantly more often in cases than in the controls (49.3% versus 29.7%;P < 0.001). We did not find statistically significant differences in the genotype distribution in GSTP1 (Ile105Val) polymorphism between cases and controls (40.5% versus 46.0%). Conclusions: We may conclude that individuals homozygous for the deletion of GSTT1 are at an ≈ 2-fold-greater risk of DR, whereas the GSTM1 deficiency is associated with lower frequency of DR in type 2 diabetics.     

A hemochromatosis-causing mutation C282Y is a risk factor for proliferative diabetic retinopathy in Caucasians with type 2 diabetes

Iron metabolism might be involved in the pathogenesis of type 2 diabetes and in the pathogenesis of diabetic retinopathy. C282Y and H63D mutations in the hemochromatosis (HFE) gene are associated with increased serum iron levels and consequently with hereditary hemochromatosis. In the present study, we searched for a relationship between C282Y and H63D gene mutations and the development of proliferative diabetic retinopathy in Caucasians with type 2 diabetes. For this purpose, 90 subjects with type 2 diabetes with proliferative diabetic retinopathy (PDR) were compared to 133 diabetic subjects without PDR. There was a significantly higher frequency of the C282Y heterozygotes in patients with PDR compared to subjects without it (OR=3.0, 95% CI=1.2–8.0; p=0.02), whereas no association was demonstrated between PDR and H63D genotypes (OR=1.1, 95% CI=0.6–2.2; p=0.7). Logistic regression analysis revealed that the C282Y mutation was a significant independent risk factor for the development of PDR (OR=6.1, 95% CI=1.2–30.5; p=0.027). These data suggest that heterozygosity for C282Y might be a novel risk factor for PDR in Caucasians with type 2 diabetes.     

血管紧张素I转换酶基因多态性与糖尿病视网膜病和糖尿病心肌梗塞关联

目的探讨血管紧张素Ⅰ转换酶(angiotensin Ⅰ-converting enzyme, ACE)基因多态性与糖尿病视网膜病和心肌梗塞之间的关联性.方法应用PCR技术,对1型糖尿病33例视网膜病患者和36例非视网膜病患者、2型糖尿病68例伴心肌梗塞患者和57例伴视网膜病患者以及190例无并发症患者的ACE基因插入/缺失型多态性进行了检测.结果 ACE基因与视网膜病之间无关联.而2型糖尿病心肌梗塞患者与非心肌梗塞患者比较, DD纯合子频率显著增高(41.2% vs 33.2%),D等位基因频率也显著增高,差异有显著性(P<0.05).结论 D等位基因(相对风险为1.50)和DD基因型(相对风险为1.33)可能是2型糖尿病心肌梗塞发生的风险因子.     

血管紧张素Ⅰ转换酶基因多态性与糖尿病视网膜病和糖尿病心肌梗塞关联

目的　探讨血管紧张素 转换酶 ( angiotensin - converting enzyme,ACE)基因多态性与糖尿病视网膜病和心肌梗塞之间的关联性。方法　应用 PCR技术 ,对 1型糖尿病 33例视网膜病患者和 36例非视网膜病患者、2型糖尿病 6 8例伴心肌梗塞患者和 5 7例伴视网膜病患者以及 190例无并发症患者的ACE基因插入 /缺失型多态性进行了检测。结果　 ACE基因与视网膜病之间无关联。而 2型糖尿病心肌梗塞患者与非心肌梗塞患者比较 ,DD纯合子频率显著增高 ( 4 1.2 % vs 33.2 % ) ,D等位基因频率也显著增高 ,差异有显著性 ( P<0 .0 5 )。结论　 D等位基因 (相对风险为 1.5 0 )和 DD基因型 (相对风险为 1.33)可能是 2型糖尿病心肌梗塞发生的风险因子     

亚甲基四氢叶酸还原酶基因677C→T突变与糖尿病微血管病

目的 研究中国人群2型糖尿病患者中,亚甲基四氢叶酸还原酶（methylenetetrahydrofolate reductase,MTHFR)基因677C→T突变与糖尿病微血管病的关系。方法 将168名研究对象分为正常对照组、糖尿病和糖尿病微血管病（diabetic microangiopathy,DMA)组,采用PCR－RFLP检测各组MTHFR677C→T突变,统计各组对象的突变频率。结果 与无糖尿病微血管病患者和正常人相比,糖尿病微血管病患者MTHFR677C→T（T／T基因型）变频率更高（22．6％vs6.7%和5．5％,P＜0．01）,MTHFRT／T基因型对MDA的OR值为3．36,P＜0．001。结论 糖尿病患者中MTHFR677C→T突变为其发生微血管病的一种遗传易感因素。     

Genetic variation screening and association studies of the adenylate cyclase activating polypeptide 1 (ADCYAP1) gene in patients with type 2 diabetes

Adenylate cyclase activating polypeptide 1 (ADCYAP1) is a pancreatic neuropeptide and modulates glucose-stimulated insulin secretion. The ADCYAP1 gene is located on chromosome 18p11 linked to type 2 diabetes. To test whether it is a candidate gene for type 2 diabetes, screening of the gene in Finnish and Swedish type 2 diabetic patients was done. Two novel SNPs, g.9863G>A (G54D) in exon 3 and g.12712C>G in the 3'-UTR of exon 5 of the ADCYAP1 gene (accession number X60435), were found. PCR-RFLP genotyping was then performed in a total of 253 type 2 diabetic patients and 253 non-diabetic control subjects. Transmission disequilibrium test (TDT) was performed in 132 parent-offspring trios. The G allele frequencies of g.9863G>A (G54D) and g.12712C>G of the ADCYAP1 gene were higher in type 2 diabetic patients than in non-diabetic control subjects (21.0% vs 15.8%, P=0.04; 5.3% vs 3.0%, P=0.045). However, no significant differences in clinical variables was seen between the different genotype carriers, and also no transmission distortion of the G allele of SNP g.9863G>A (G54D) was observed in 132 parent-offspring trios. The present study thus suggest that the variants in the ADCYAP1 gene may not be major influence of the susceptibility to type 2 diabetes in Finnish and Swedish Caucasians.     

Polymorphism in gene for islet autoantigen, IA-2, and type 1 diabetes in Japanese subjects

Autoantibodies against IA-2 have been detected in up to 86% of newly diagnosed patients with type 1 diabetes and appear to identify a subgroup of prediabetic subjects who rapidly progress to type 1 diabetes. We examined the association of IA-2 gene polymorphism with type 1 diabetes in Japanese subjects. A total of 276 Japanese subjects were studied for disease association and, in addition, another 53 patients were studied for association with the autoantibody status to IA-2. A microsatellite marker D2S1753E, located in the intron of the IA-2 gene, was used as a genetic marker in this study. In Japanese, two alleles (161mu and 165mu) were more frequent, and the 163mu allele was less frequent than in Caucasians (p = 0.0001). There was no significant difference in frequencies of alleles between diabetic patients and control subjects. The frequency of IA-2 gene polymorphism was not significantly different between patients stratified by age-at-onset, or between patients with and without susceptible HLA, DRB1*0405, DRB1*0802 and DRB1*0901. There was no significant difference in allele frequency of the IA-2 gene polymorphism between patients with and without autoantibody to IA-2. In conclusion, IA-2 gene polymorphism is not associated with either susceptibility to, or heterogeneity in type 1 diabetes in Japanese subjects.     

Evidence for association between vitamin D receptor BsmI polymorphism and type 1 diabetes in Japanese

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.