Reactive oxygen species damaged human serum albumin in patients with type 1 diabetes mellitus: biochemical and immunological studies

The role of hydroxyl radical (.OH) damaged human serum albumin (HSA) in type 1 diabetes has been investigated in the present study. Hydroxyl radical induced modification on HSA has been studied by UV absorption spectroscopy, ANS fluorescence and carbonyl estimation. Hydroxyl radical modified HSA was found to be highly immunogenic in rabbits as compared to native HSA. The binding characteristics of circulating autoantibodies in type 1 diabetes patients against native and modified HSA were assessed. Diabetes patients (n=31) were examined by direct binding ELISA and the results were compared with healthy age-matched controls (n=22). High degree of specific binding by 54.8% of patients sera towards .OH modified HSA, in comparison to its native analogue (p<0.05) was observed. Sera from those type 1 diabetes patients having smoking history, high aging with high degree of disease showed substantially stronger binding to .OH modified HSA over native HSA in particular. Normal human sera showed negligible binding with either antigen. Competitive inhibition ELISA reiterates the direct binding results. Gel retardation assay further substantiated the enhanced recognition of modified HSA by circulating autoantibodies in diabetes patients. The increase in total serum protein carbonyl levels in the diabetes patients was largely due to an increase in oxidized albumin. HSA of diabetes mellitus patients (DM-HSA) and normal subjects (normal-HSA) were purified on a Sephacryl S-200 HR column. Spectroscopic analysis confirmed that the DM-HSA samples contained higher levels of carbonyls than normal-HSA (p<0.001). DM-HSA was conformationally altered, with more exposure of its hydrophobic regions. Collectively, the oxidation of plasma proteins, especially HSA, might enhance oxidative stress in type 1 diabetes mellitus patients.     

Increased tissue kallikrein amidase activity in urine of patients with type 1 diabetes under insulin therapy, and in those with gestational diabetes mellitus not under insulin therapy

Human tissue kallikrein (hK1) is reduced in hypertension, cardiovascular and renal diseases. There is little information on the participation of hK1 in type 1 diabetes mellitus (DM), type 2 DM, and gestational diabetes mellitus (GDM), respectively. The aim of this study was to evaluate the roles of insulin and hyperglycemia on urinary hK1 activity in type 1 DM and in GDM. Forty-three type 1 DM patients (5–35 years, disease duration ?5 years, receiving insulin, HbA_1c > 7.6%) were selected. Forty-three healthy individuals, paired according to gender and age, were used as controls. Thirty GDM patients (18–42 years, between the 24th and 37th week of pregnancy, recently diagnosed, not under insulin therapy) were also selected. Thirty healthy pregnant (18–42 years, between the 24th and 37th week of pregnancy) and 30 healthy non-pregnant women (18–42 years) were selected as controls. Random midstream urine was used. hK1 amidase activity was estimated with D-Val-Leu-Arg-Nan substrate. Creatinine was determined by Jaffe’s method. hK1 specific amidase activity was expressed as μM/(min mg creatinine) to correct for differences in urine flow rate. hK1 specific amidase activity was significantly higher in the urine of type 1 DM than in controls, and in the urine of GDM patients than in healthy pregnant women and healthy non-pregnant women, respectively. The data suggest that hyperglycemia, rather than insulin, is involved in the mechanism of increased hK1 specific amidase activity in both type 1 DM and GDM patients, respectively.     

Androgen receptor: a new player associated with apoptosis and proliferation of pancreatic beta-cell in type 1 diabetes mellitus

Androgen receptor (AR) mediates a wide range of cellular processes, such as proliferation, differentiation and apoptosis. Here we sought to identify whether AR was located in pancreatic beta-cells and investigate its functions in type 1 diabetes induced by multiple low doses of streptozotocin. Double/triple immunofluorescence, Western blot and semi-quantitative RT-PCR were carried out to determine variances of AR expression in beta-cells and correlation between AR and apoptosis/proliferation of beta-cells with progress of diabetes. In addition, in vitro primary beta-cells from control mice were cultured for 3 days or 6 days with compound stimulation in order to further identify effect of AR on beta-cell apoptosis and proliferation. AR expression in beta-cells peaked in control and 1-day diabetic mice, gradually and significantly decreased, even disappeared in diabetic mice with progress of diabetes. TUNEL-positive beta-cells were concomitant with overexpression of AR, and Ki67-positive beta-cells showed extremely weak, even negative AR staining. In vitro, AR could mediate beta-cell apoptosis, and AR antagonist flutamide contributed to beta-cell proliferation. In conclusion, AR is abundantly expressed in pancreatic beta-cell cytoplasm of control mice. With progress of type 1 diabetes, decrement of AR expression in diabetic mice contributes to prohibit beta-cells from apoptosis, and is strongly associated with beta-cell proliferation.     

Suppressive effects of electrolyzed reduced water on alloxan-induced apoptosis and type 1 diabetes mellitus

Electrolyzed reduced water, which is capable of scavenging reactive oxygen species, is attracting recent attention because it has shown improved efficacy against several types of diseases including diabetes mellitus. Alloxan produces reactive oxygen species and causes type 1 diabetes mellitus in experimental animals by irreversible oxidative damage to insulin-producing β-cells. Here, we showed that electrolyzed reduced water prevented alloxan-induced DNA fragmentation and the production of cells in sub-G1 phase in HIT-T15 pancreatic β-cells. Blood glucose levels in alloxan-induced type 1 diabetes model mice were also significantly suppressed by feeding the mice with electrolyzed reduced water. These results suggest that electrolyzed reduced water can prevent apoptosis of pancreatic β-cells and the development of symptoms in type 1 diabetes model mice by alleviating the alloxan-derived generation of reactive oxygen species.     

磺酰脲受体1基因多态性与2型糖尿病的相关性

目的：研究磺酰脲受体1（sulfonylurea receptorl,SUR1）基因外显子16-3c／t多态性与湖北汉族人群2型糖尿病的相关性。方法：采用同胞对（2型糖尿病人及其正常同胞）和随机病例一对照两种实验设计,应用PCR-RFLP方法分析共405个样本的SUR1基因外显子16-3c／t多态性,并测定身高、体重、腰围、臀围、血压、空腹血糖等生理生化指标。结果：两种实验设计中病例组与对照组的基因型和等位基因频率均无显著性差异（P〉0．05）。结论：在湖北汉族人群中未发现SUR1基因外显子16-3c／t多态性与2型糖尿病之间存在关联,该基因座可能不是该人群的致病基因。     

肠道微生物与1型糖尿病的相关性研究

1型糖尿病(type 1 diabetes, T1D)是一种自身免疫性疾病,越来越多的证据支持肠道菌群是T1D发病的重要因素。在T1D发生前,观察到肠道通透性发生改变,使抗原透过肠黏膜进而攻击胰岛β细胞。患有T1D宿主体内的肠道微生物也与健康宿主的微生物有别,其调节性T细胞、Toll样受体(toll-like receptor, TLR)、丁酸、粘蛋白、胰高血糖素样肽-1(glucagon-likepeptide1,GLP-1)等可能与T1D有关。尽管通过细菌定植促进自身免疫的机制在糖尿病动物模型中虽已发现,但有些问题目前尚不清楚。现就肠道黏膜通透性与T1D的关系、宿主体内微生物组成的变化、肠道微生物与T1D的相关性作一阐述。     

Assessment of gender-related differences in vitamin D levels and cardiovascular risk factors in Saudi patients with type 2 diabetes mellitus

Diabetes is a major risk factor for cardiovascular disease (CVD) including stroke, coronary heart disease, and peripheral artery disease. It remains a leading cause of mortality throughout the world, affecting both women and men. This investigation was aimed to study gender based differences in cardiovascular risk factors of adult population with type-2 diabetes mellitus (T2DM) and to check the correlation between serum HbA1C, lipid profile and serum vitamin D levels, in T2DM patients of Riyadh, Saudi Arabia. This hospital-based cross-sectional study involving subjects was divided into two gender based groups; normal male (800), diabetic male (800) and normal female (800) and T2DM females (800). Blood samples were analyzed for fasting glucose (FBG), HbA1c, total cholesterol (TC), triglycerides (Tg), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and serum levels of 25(OH)-vitamin D in all groups. All the glycemic control parameters and lipid profile parameters were found to be significantly different in diabetic vs non-diabetic group (p < 0.001) in both genders. The results also show that vitamin D concentration decreased significantly (p < 0.001) in diabetic patients than the healthy individuals in both the genders. Vitamin-D and HbA1C were negatively correlated in both males and females in T2DM patients and significant at P < 0.05. Our study reveals that dyslipidemia remains one of the major risk factors of CVD in T2DM. In addition to dyslipidemia, decreased levels of vitamin-D associated with increased HbA1C alarms the early diagnosis of Type 2 Diabetes.     

Suppressive effects of natural reduced waters on alloxan-induced apoptosis and type 1 diabetes mellitus

Insulin-producing cells express limited activities of anti-oxidative enzymes. Therefore, reactive oxygen species (ROS) produced in these cells play a crucial role in cytotoxic effects. Furthermore, diabetes mellitus (DM) development is closely linked to higher ROS levels in insulin-producing cells. Hita Tenryosui Water^® (Hita T. W., Hita, Japan) and Nordenau water (Nord. W., Nordenau, Germany), referred to as natural reduced waters (NRWs), scavenge ROS in cultured cells, and therefore, might be a possibility as an alternative to conventional pharmacological agents against DM. Therefore, this study aimed to investigate the role of NRWs in alloxan (ALX)-induced β-cell apoptosis as well as in ALX-induced diabetic mice. NRWs equally suppressed DNA fragmentation levels. Hita T. W. and Nord. W. ameliorated ALX-induced sub-G₁ phase production from approximately 40% of control levels to 8.5 and 11.8%, respectively. NRWs restored serum insulin levels (p < 0.01) and reduced blood glucose levels (p < 0.01) in ALX-induced mice. Hita T. W. restored tissue superoxide dismutase (SOD) (p < 0.05) activity but not tissue catalase activity. Hita T. W. did not elevate SOD or catalase activity in HIT-T15 cells. Nord. W. restored SOD (p < 0.05) and catalase (p < 0.05) activity in both cultured cells and pancreatic tissue to normal levels. Even though variable efficacies were observed between Hita T. W. and Nord. W., both waters suppressed ALX-induced DM development in CD-1 male mice by administering NRWs for 8 weeks. Our results suggest that Hita T. W. and Nord. W. protect against ALX-induced β-cell apoptosis, and prevent the development of ALX-induced DM in experimental animals by regulating ALX-derived ROS generation and elevating anti-oxidative enzymes. Therefore, the two NRWs tested here are promising candidates for the prevention of DM development.     

Double transgenic mice with type 1 diabetes mellitus develop somatic, metabolic and vascular disorders

The double transgenic mice (dTg) were obtained by mating: (i) transgenic mice expressing the hemagglutinin of influenza virus under the insulin promoter with (ii) transgenic mice expressing specific T lymphocytes with receptor for the immunodominant epitope of the same virus. In this study we show that dTg mice developed type 1 diabetes mellitus associated with hyperglycemia, low level of plasma insulin, glucosuria, weight loss and approximately 90% mortality (at 3 months biological age). The membrane of red blood cells was more sensitive to osmotic shock in diabetic mice, compared to non-diabetic mice, assessing systemic oxidative stress. Both vasoconstriction and vasorelaxation of the renal arteries decreased significantly in diabetic mice (compared to the control group of non-diabetic mice) related to the phenotypic change of endothelium and smooth muscle cells within the artery wall. This animal model, may be used in developing various strategies to study pancreatic beta-cell function, as well as for a better metabolic control conducting to a reduced risk of vascular complications.     

Trace elements,oxidative stress and glycemic control in young people with type 1 diabetes mellitus

Trace elements and oxidative stress are associated with glycemic control and diabetic complications in type 1 diabetes mellitus. In this study, we analyzed the levels of serum copper, zinc, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) and urinary MDA and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in 33 type 1 diabetic patients with optimal and suboptimal glycemic control (HbA_1C < 9.0%) and 40 patients with poor glycemic control (HbA_1C ≥ 9%) and 27 age- and sex-matched non-diabetic controls to evaluate the differences between these markers in different glycemic control states. Diabetic patients, especially poor-glycemic-control subjects (HbA_1C ≥ 9%), exhibited significantly lower levels of serum zinc and increased levels of serum copper (and, therefore, increased serum copper-to-zinc ratios), serum SOD, blood MDA, and urinary MDA and 8-OHdG, relative to non-diabetic subjects. Furthermore, significant correlations existed in these patients between the serum copper, serum copper-to-zinc ratio, and urinary MDA (all p < 0.001) and the levels of urinary 8-OHdG (p = 0.007) and HbA_1C. Our results suggest that high serum copper levels and oxidative stress correlate with glycemic control. Therefore, strict glycemic control, decreased oxidative stress, and a lower copper concentration might prevent diabetic complications in patients with type 1 diabetes mellitus.     

肠道菌群与儿童1型糖尿病关系的研究进展

1型糖尿病（type 1 diabetes mellitus,T1DM）是胰岛β细胞被破坏而导致胰岛素绝对缺乏所致。T1DM绝大多数属于自身免疫性疾病,由遗传及环境因素共同参与其发病过程。儿童糖尿病95%以上为T1DM。近年来儿童T1DM发病率呈现逐年上升趋势。研究表明肠道菌群与儿童T1DM的发病密切相关,T1DM儿童肠道菌群分布失调,肠道菌群可能通过影响肠道免疫系统和改变肠壁通透性来参与T1DM的发病过程。动物实验的研究中,改变肠道菌群分布和应用益生菌可以预防和延缓T1DM的发病。干预肠道菌群是否会预防、延缓儿童T1DM的发生尚需要进一步的研究,希望干预肠道菌群能为预防和治疗儿童T1DM提供新的方向。     

Novel protein tyrosine phosphatase 1B inhibitors: interaction requirements for improved intracellular efficacy in type 2 diabetes mellitus and obesity control

Resistance to the hormones insulin and leptin are hallmarks in common for type 2 diabetes mellitus and obesity. Both conditions are associated with increased activity and expression of protein tyrosine phosphatase (PTP)1B. Therefore, inhibition of PTP1B activity or down-regulation of its expression should ameliorate insulin and leptin resistance, and may hold therapeutic utility in type 2 diabetes mellitus and obesity control. This background has motivated the fervent search for PTP1B inhibitors, carried out in the recent years. The purpose of this review is to provide the most recent advances in understanding the structural details of PTP1B molecule relevant to the interactions with inhibitors, and the progress towards compounds with enhanced membrane permeability, affinity, specificity, and potency on intracellular PTP1B; several inhibitors of benefit in type 2 diabetes mellitus and obesity control are presented and discussed.     

1型糖尿病的干细胞治疗研究进展

1型糖尿病是由于产生胰岛素的β细胞特征性的被破坏造成的自身免疫疾病.理想的治疗方法就是通过外源的或内源的移植使胰腺细胞再生.干细胞包括胚胎干细胞和成体干细胞,它们都有各自的特点.最近的数据显示这些干细胞能够在体外特定的培养条件下分化成为胰岛素产生细胞.虽然在很多的案例中,来源于干细胞的胰岛素产生细胞在实验中可以逆转糖尿病模型动物的高血糖,但是,要想达到明确的应用于临床,仍然存在几个问题：主要有与胰岛β细胞相似细胞系的获得、移植后的免疫相容性问题和肿瘤的形成.本文综述了从胚胎干细胞和成体干细胞获得胰岛素产生细胞的不同方法、分化后的细胞移植治疗情况以及干细胞治疗1型糖尿病存在的主要问题和可能解决的办法.     

2型糖尿病与糖尿病肾病患者微炎症及肠道微生物多样性分析

目的 分析2型糖尿病(T2DM)及糖尿病肾病(DKD)患者微炎症情况和肠道微生物多样性。 方法 将2016年4月至2019年7月在我院进行治疗的68例T2DM患者(T2DM组)和57例DKD患者(DKD组)纳入研究,选择同期于我院进行健康体检的36例志愿者作为对照组。收集3组对象一般资料、血液标本和粪便标本,测定血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDLC)、高密度脂蛋白胆固醇(HDLC)、糖化血红蛋白(HbAlc)、空腹血糖(FBG)、超敏C反应蛋白(hsCRP)、白细胞介素6(IL6)水平,并对肠道细菌进行16S rDNA序列测序。比较3组对象一般资料,血液指标,肠道菌群门水平构成情况,肠道菌群多样性,肠道菌属差异性,并对患者炎性指标与菌群种类进行相关性分析。 结果 DKD组患者糖尿病病程长于T2DM组(P结论 2型糖尿病患者普遍存在微炎症和肠道菌群失衡,微炎症程度与肾脏病变和肠道菌群数量密切相关。T2DM与DKD患者在肠道菌群结构上具有一致性和差异性,肠道菌群检测有可能成为预测T2DM患者发生肾脏病变的风险指标。     

Regulatory T cells (CD4CD25FoxP3) expansion in systemic sclerosis correlates with disease activity and severity

Background

The role and function of T regulatory (Treg) cells have not been fully investigated in patients with systemic sclerosis (SSc).

Methods

Ten patients with SSc donated 20 ml of peripheral blood. Activity (Valentini) and severity (Medsger) scores for SSc were calculated for all patients. Healthy volunteers (controls) were matched to each patient by gender and age. CD4⁺ cells were separated using the MACS system. The numbers of Treg cells were estimated by flow cytometry after staining for CD4, CD25, and FoxP3 and calculated as patient-to-control ratio separately for each experiment. Correlations with activity and severity indices of the disease were performed. Twenty-four-hour production of TGF-β and IL-10 by activated CD4⁺ cells was measured by ELISA in culture supernatants.

Results

The numbers of Treg cells, expressed as patient-to-control ratio, correlated significantly with both activity and severity indices (r = 0.71, p = 0.034 and r = 0.67, p = 0.044, respectively). ELISA-measured production of TGF-β and IL-10 by CD4⁺ cells was similar in patients and controls.

Conclusions

Increased numbers of Treg cells are present in patients with SSc, correlating with activity and severity of the disease. This expansion of Treg cells was not accompanied, however, by heightened TGF-β or IL-10 production. Further studies to elaborate the causes and functional significance of Treg cell expansion in SSc are needed.     

锌转运蛋白8与1型和2型糖尿病的研究进展

ZnT8(zinc transporter,member8)是锌离子转运蛋白,主要定位于胰岛β细胞,能将胞浆锌离子转运至胰岛素储存/分泌性囊泡内,其转运功能降低会影响胰岛素合成、储存和分泌,能增加2型糖尿病(T2DM)的发病风险。ZnT8蛋白也可作为抗原引起β细胞自身免疫损伤,诱发1型糖尿病(T1DM)。ZnT8基因多态性是引起其锌离子转运功能和免疫原性变化的重要因素,与糖尿病的发生、发展密切相关。该文综述了ZnT8与T1DM和T2DM的研究进展,提示ZnT8可作为糖尿病防治的新药物靶点。     

A meta-analysis of association of vitamin D receptor BsmI gene polymorphism with the risk of type 1 diabetes mellitus

Abstract

Association between vitamin D receptor (VDR) BsmI (rs1544410) gene polymorphism and the risk of type 1 diabetes mellitus (T1DM) from the published reports are still conflicting. This study was conducted to evaluate the relationship between VDR BsmI gene polymorphism and the risk of T1DM using meta-analysis method. The association studies were identified from PubMed, and Cochrane Library on 1 December 2013, and eligible investigations were included and synthesized using meta-analysis method. Twenty-three reports were recruited into this meta-analysis for the association of VDR BsmI gene polymorphism with T1DM susceptibility. In overall populations, bb genotype was associated with T1DM, but the B allele and BB genotype were not. In Asians and Latino population, B allele and bb genotype were associated with TIDM risk, but BB genotype was not. In Caucasians, VDR BsmI gene polymorphism was not associated with the T1DM risk. In Africans, B allele and BB genotype were associated with T1DM risk, but the bb genotype was not. However, the sample size for Latino population and Africans was small. In conclusion, VDR BsmI B allele, bb genotype was associated with T1DM risk in Asians, and bb genotype was associated with T1DM risk in overall populations. However, more studies should be conducted to confirm it.     

Association of low GLP-1 with oxidative stress is related to cardiac disease and outcome in patients with type 2 diabetes mellitus: A pilot study

Oxidative stress (OS) contributes to cardiovascular damage in type 2 diabetes mellitus (T2DM). The peptide glucagon-like peptide-1 (GLP-1) inhibits OS and exerts cardiovascular protective actions. Our aim was to investigate whether cardiac remodeling (CR) and cardiovascular events (CVE) are associated with circulating GLP-1 and biomarkers of OS in T2DM patients. We also studied GLP-1 antioxidant effects in a model of cardiomyocyte lipotoxicity. We examined 72 T2DM patients with no coronary or valve heart disease and 14 nondiabetic subjects. A median of 6 years follow-up information was obtained in 60 patients. Circulating GLP-1, dipeptidyl peptidase-4 activity, and biomarkers of OS were quantified. In T2DM patients, circulating GLP-1 decreased and OS biomarkers increased, compared with nondiabetics. Plasma GLP-1 was inversely correlated with serum 3-nitrotyrosine in T2DM patients. Patients showing high circulating 3-nitrotyrosine and low GLP-1 levels exhibited CR and higher risk for CVE, compared to the remaining patients. In palmitate-stimulated HL-1 cardiomyocytes, GLP-1 reduced cytosolic and mitochondrial oxidative stress, increased mitochondrial ATP synthase expression, partially restored mitochondrial membrane permeability and cytochrome c oxidase activity, blunted leakage of creatine to the extracellular medium, and inhibited oxidative damage in total and mitochondrial DNA. These results suggest that T2DM patients with reduced circulating GLP-1 and exacerbated OS may exhibit CR and be at higher risk for CVE. In addition, GLP-1 exerts antioxidant effects in HL-1 palmitate-overloaded cardiomyocytes. It is proposed that therapies aimed to increase GLP-1 may counteract OS, protect from CR, and prevent CVE in patients with T2DM.     

Mononuclear and polymorphonuclear leukocytes show increased fructose-1,6-bisphosphatase activity in patients with type 1 diabetes mellitus

The activity and localization of fructose-1,6-bisphosphatase (FBPase; EC 3.1.3.11) in blood leukocytes of patients with type 1 diabetes mellitus and healthy adults were investigated immunocytochemically. The amount of polymorphonuclear (PMN) and mononuclear (MN) cells with positive FBPase immunocytochemical reaction was 57% and 68%, respectively, in pathological, and 38% and 42%, respectively, in healthy donors. Results of light microscopic investigations were confirmed by measurements of FBPase activity following lysis of PMN and MN cells. The enzyme activity of PMN and MN leukocytes was higher in diabetes mellitus than in healthy adults, by 30% and 127%, respectively. Using immunocytochemistry together with electron microscopy, FBPase was detected not only in the cytoplasm but also in the nucleus of leukocytes of both patients with insulin-dependent diabetes mellitus and healthy donors.     

HLA polymorphism in type 1 diabetes Tunisians

Several studies of the association between HLA and type 1 diabetes have been carried out revealing differences between ethnic groups. Our study, as part of the studies that should be performed about this association in the rest of the word, aims at elucidating the HLA DRB1, DQB1 polymorphism in Tunisian type 1 diabetes. This study includes 43 unrelated type 1 diabetes patients, and their mean age at onset is less than 15 years. Analysis of the frequency of alleles and haplotypes in these subjects, compared to a reference group (n = 101) led to the following results. 1) The Tunisian insulin-dependent diabetics present similarities as well as differences with other ethnic groups (Caucasians, North Africans). 2) The haplotype DRB1*04 DQ*0302 and DRB1*03 DQB1*0201 is positively associated to type 1 diabetes. 3) The heterozygotic genotype DRB1*04 DQB1*0302 / DRB1*03 DQB1*0201 is strongly associated to type 1 diabetes. 4) The haplotypes DRB1*01501 DQB1*0602 and DRB1*11 DQB1*0301 proved to be protective. In addition, the study of the subtypes DRB1*04 showed that alleles DRB1*0405 predispose to type 1 diabetes, whereas the allele DRB1*0403, which is in linkage disequilibrium with the DQB1*0402 in the Tunisian population, has a protective effect.