Alteration of the Thymic T Cell Repertoire by Rotavirus Infection Is Associated with Delayed Type 1 Diabetes Development in Non-Obese Diabetic Mice

Rotaviruses are implicated as a viral trigger for the acceleration of type 1 diabetes in children. Infection of adult non-obese diabetic (NOD) mice with rotavirus strain RRV accelerates diabetes development, whereas RRV infection in infant NOD mice delays diabetes onset. In this study of infant mice, RRV titers and lymphocyte populations in the intestine, mesenteric lymph nodes (MLN) and thymus of NOD mice were compared with those in diabetes-resistant BALB/c and C57BL/6 mice. Enhanced intestinal RRV infection occurred in NOD mice compared with the other mouse strains. This was associated with increases in the frequency of CD8αβ TCRαβ intraepithelial lymphocytes, and their PD-L1 expression. Virus spread to the MLN and T cell numbers there also were greatest in NOD mice. Thymic RRV infection is shown here in all mouse strains, often in combination with alterations in T cell ontogeny. Infection lowered thymocyte numbers in infant NOD and C57BL/6 mice, whereas thymocyte production was unaltered overall in infant BALB/c mice. In the NOD mouse thymus, effector CD4⁺ T cell numbers were reduced by infection, whereas regulatory T cell numbers were maintained. It is proposed that maintenance of thymic regulatory T cell numbers may contribute to the increased suppression of inflammatory T cells in response to a strong stimulus observed in pancreatic lymph nodes of adult mice infected as infants. These findings show that rotavirus replication is enhanced in diabetes-prone mice, and provide evidence that thymic T cell alterations may contribute to the delayed diabetes onset following RRV infection.     

Low Incidence of Spontaneous Type 1 Diabetes in Non-Obese Diabetic Mice Raised on Gluten-Free Diets Is Associated with Changes in the Intestinal Microbiome

Human and animal studies strongly suggest that dietary gluten could play a causal role in the etiopathogenesis of type 1 diabetes (T1D). However, the mechanisms have not been elucidated. Recent reports indicate that the intestinal microbiome has a major influence on the incidence of T1D. Since diet is known to shape the composition of the intestinal microbiome, we investigated using non-obese diabetic (NOD) mice whether changes in the intestinal microbiome could be attributed to the pro- and anti-diabetogenic effects of gluten-containing and gluten-free diets, respectively. NOD mice were raised on gluten-containing chows (GCC) or gluten-free chows (GFC). The incidence of diabetes was determined by monitoring blood glucose levels biweekly using a glucometer. Intestinal microbiome composition was analyzed by sequencing 16S rRNA amplicons derived from fecal samples. First of all, GCC-fed NOD mice had the expected high incidence of hyperglycemia whereas NOD mice fed with a GFC had significantly reduced incidence of hyperglycemia. Secondly, when the fecal microbiomes were compared, Bifidobacterium, Tannerella, and Barnesiella species were increased (p = 0.03, 0.02, and 0.02, respectively) in the microbiome of GCC mice, where as Akkermansia species was increased (p = 0.02) in the intestinal microbiomes of NOD mice fed GFC. Thirdly, both of the gluten-free chows that were evaluated, either egg white based (EW-GFC) or casein based (C-GFC), significantly reduced the incidence of hyperglycemia. Interestingly, the gut microbiome from EW-GFC mice was similar to C-GFC mice. Finally, adding back gluten to the gluten-free diet reversed its anti-diabetogenic effect, reduced Akkermansia species and increased Bifidobacterium, Tannerella, and Barnesiella suggesting that the presence of gluten is directly responsible for the pro-diabetogenic effects of diets and it determines the gut microflora. Our novel study thus suggests that dietary gluten could modulate the incidence of T1D by changing the gut microbiome.     

Identification of the Locus Associated with Diabetic Nephropathy in Type 1 Diabetes Mellitus

Polymorphic tetranucleotide microsatellites D3S1512, D3S1744, D3S1550, and D3S2326 were used to study the association of chromosome region 3q21–q25 neighboring the angiotensin II receptor type 1 gene (AT ₂ R1) with diabetic nephropathy (DN) in diabetes mellitus type 1 (DM1). Allele and genotype frequencies were compared for DM1 patients with (N = 39) or without (N = 62) DN. Fisher's exact test with Bonferroni's correction revealed significant differences in frequencies of two D3S2326 alleles, one D3S1512 allele, and one allele and one genotype of D3S1550. No significant difference was observed with D3S1744. Thus, region 3q21–q25 proved tightly associated with DN in ethnic Russians with DM1 from Moscow.     

IL-2 Immunotherapy Reveals Potential for Innate Beta Cell Regeneration in the Non-Obese Diabetic Mouse Model of Autoimmune Diabetes

Type-1 diabetes (T1D) is an autoimmune disease targeting insulin-producing beta cells, resulting in dependence on exogenous insulin. To date, significant efforts have been invested to develop immune-modulatory therapies for T1D treatment. Previously, IL-2 immunotherapy was demonstrated to prevent and reverse T1D at onset in the non-obese diabetic (NOD) mouse model, revealing potential as a therapy in early disease stage in humans. In the NOD model, IL-2 deficiency contributes to a loss of regulatory T cell function. This deficiency can be augmented with IL-2 or antibody bound to IL-2 (Ab/IL-2) therapy, resulting in regulatory T cell expansion and potentiation. However, an understanding of the mechanism by which reconstituted regulatory T cell function allows for reversal of diabetes after onset is not clearly understood. Here, we describe that Ab/IL-2 immunotherapy treatment, given at the time of diabetes onset in NOD mice, not only correlated with reversal of diabetes and expansion of Treg cells, but also demonstrated the ability to significantly increase beta cell proliferation. Proliferation appeared specific to Ab/IL-2 immunotherapy, as anti-CD3 therapy did not have a similar effect. Furthermore, to assess the effect of Ab/IL-2 immunotherapy well after the development of diabetes, we tested the effect of delaying treatment for 4 weeks after diabetes onset, when beta cells were virtually absent. At this late stage after diabetes onset, Ab/IL-2 treatment was not sufficient to reverse hyperglycemia. However, it did promote survival in the absence of exogenous insulin. Proliferation of beta cells could not account for this improvement as few beta cells remained. Rather, abnormal insulin and glucagon dual-expressing cells were the only insulin-expressing cells observed in islets from mice with established disease. Thus, these data suggest that in diabetic NOD mice, beta cells have an innate capacity for regeneration both early and late in disease, which is revealed through IL-2 immunotherapy.     

Polymorphic Gene Markers of Lipid Metabolism Are Associated with Diabetic Nephropathy in Patients with Type 1 Diabetes Mellitus

In groups of type 1 diabetes mellitus patients with and without clinical signs of diabetic nephropathy (n = 62 and 68, respectively), a search was made for associations between diabetic nephropathy and the polymorphic marker ε2/ε3/ε4 of apolipoprotein E gene (APOE), I/D marker of apolipoprotein B gene (APOB), and Ser447Ter marker of lipoprotein lipase-encoding gene (LPL). The risk of diabetic nephropathy was higher in the carriers of allele ε3 and genotype ε3/ε3 of the polymorphic marker ε2/ε 3/ε4 of APOE gene as well as in the carriers of allele I and APOB genotype I/I gene (OR = 2.08 and 2.16; 1.91 and 2.11, respectively). Conversely, the carriers of allele D showed a reduced risk of this complication (OR = 0.52). No significant differences in distribution of alleles and genotypes of the polymorphic marker Ser447Ter of LPL gene were found between the groups. Our results indicate that the genes encoding two major components of lipid metabolism are involved in the development of diabetic nephropathy in patients with type 1 diabetes mellitus.__________Translated from Genetika, Vol. 41, No. 7, 2005, pp. 931–937.Original Russian Text Copyright © 2005 by Yakunina, Shestakova, Voron’ko, Vikulova, Savost’yanov, Chugunova, Shamkhalova, Dedov, Nosikov.     

Effect of Insulin on ACE2 Activity and Kidney Function in the Non-Obese Diabetic Mouse

We studied the non-obese diabetic (NOD) mice model because it develops autoimmune diabetes that resembles human type 1 diabetes. In diabetic mice, urinary albumin excretion (UAE) was ten-fold increased at an “early stage” of diabetes, and twenty-fold increased at a “later stage” (21 and 40 days, respectively after diabetes diagnosis) as compared to non-obese resistant controls. In NOD Diabetic mice, glomerular enlargement, increased glomerular filtration rate (GFR) and increased blood pressure were observed in the early stage. In the late stage, NOD Diabetic mice developed mesangial expansion and reduced podocyte number. Circulating and urine ACE2 activity were markedly increased both, early and late in Diabetic mice. Insulin administration prevented albuminuria, markedly reduced GFR, blood pressure, and glomerular enlargement in the early stage; and prevented mesangial expansion and the reduced podocyte number in the late stage of diabetes. The increase in serum and urine ACE2 activity was normalized by insulin administration at the early and late stages of diabetes in Diabetic mice. We conclude that the Diabetic mice develops features of early kidney disease, including albuminuria and a marked increase in GFR. ACE2 activity is increased starting at an early stage in both serum and urine. Moreover, these alterations can be completely prevented by the chronic administration of insulin.     

Measurement of Cooling Detection Thresholds for Identification of Diabetic Sensorimotor Polyneuropathy in Type 1 Diabetes

Objective

Compared to recently-studied novel morphological measures, conventional small nerve fiber functional tests have not been systematically studied for identification of diabetic sensorimotor polyneuropathy (DSP). We aimed to determine and compare the diagnostic performance of cooling detection thresholds (CDT) in a cross-sectional type 1 diabetes cohort.

Research Design and Methods

136 subjects with type 1 diabetes and 52 healthy volunteers underwent clinical and electrophysiological examination for DSP classification concomitantly with the Toronto Clinical Neuropathy Score (TCNS) and three small fiber function tests: CDT, heart rate variability (HRV), and laser doppler imaging of axon-mediated neurogenic flare responses to cutaneous heating (LDI_FLARE). Area under the curve (AUC) and optimal thresholds were determined by receiver operating characteristic (ROC) curves in the type 1 diabetes cohort.

Results

Type 1 diabetes subjects were 42±17 years of age with mean HbA1c 7.9±1.7%. Fifty-nine (45%) met the case definition for DSP. CDT values were lowest in cases with DSP (18.3±8.4°C) compared to controls without DSP (28.4±3.5°C) and to healthy volunteers (29.6±1.8°C; p-value for both comparisons<0.0001). AUC_CDT was 0.863 which was similar to AUC_TCNS (0.858, p = 0.24) and AUC_HRV (0.788, p = 0.05), but exceeded AUC_LDIFLARE (0.750, p = 0.001). The threshold of <25.1°C was equivalent to the lower bound of the healthy volunteer 95% distribution [25.1, 30.8°C] and performed with 83% sensitivity and 82% specificity.

Conclusions

Akin to novel small fiber morphological measures, CDT is a functional test that identifies DSP with very good diagnostic performance. These findings support further research that revisits the role of CDT in early DSP detection.     

Lysine Malonylation Is Elevated in Type 2 Diabetic Mouse Models and Enriched in Metabolic Associated Proteins

Protein lysine malonylation, a newly identified protein post-translational modification (PTM), has been proved to be evolutionarily conserved and is present in both eukaryotic and prokaryotic cells. However, its potential roles associated with human diseases remain largely unknown. In the present study, we observed an elevated lysine malonylation in a screening of seven lysine acylations in liver tissues of db/db mice, which is a typical model of type 2 diabetes. We also detected an elevated lysine malonylation in ob/ob mice, which is another model of type 2 diabetes. We then performed affinity enrichment coupled with proteomic analysis on liver tissues of both wild-type (wt) and db/db mice and identified a total of 573 malonylated lysine sites from 268 proteins. There were more malonylated lysine sites and proteins in db/db than in wt mice. Five proteins with elevated malonylation were verified by immunoprecipitation coupled with Western blot analysis. Bioinformatic analysis of the proteomic results revealed the enrichment of malonylated proteins in metabolic pathways, especially those involved in glucose and fatty acid metabolism. In addition, the biological role of lysine malonylation was validated in an enzyme of the glycolysis pathway. Together, our findings support a potential role of protein lysine malonylation in type 2 diabetes with possible implications for its therapy in the future.Post-translational modifications (PTMs)¹ have been recognized as a common feature of proteins (1–3). More than 300 types of PTMs have been identified according to the Swiss-Prot database (4, 5). Most of them use small molecular compounds as group donors. For example, adenosine-triphosphate (ATP) is used in phosphorylation, S-adenosylmethionine (SAM) in methylation, and acetyl-CoA in acetylation. Lysine acylations including malonylation (6), succinylation (7), butyrylation (8), propionylation (9), and crotonylation (10) represent a group of PTMs that use intermediates of energy metabolism like malonyl-CoA, succinyl-CoA, butyryl-CoA, propionyl-CoA, and crotonyl-CoA as group donors. Among the lysine acylations, lysine malonylation was first identified in Escherichia coli (E. coli) and HeLa cells using a specific anti-Kmal (anti-malonyllysine) antibody (6). It was found in three proteins in E. coli and 17 proteins in HeLa cells. Using a novel chemical fluorescent probe, another group identified more than 300 malonylated protein candidates in HeLa cells (11). Despite the rapid progress in detection technologies and tools, functional studies of lysine malonylation and its role in human diseases have been lagging behind.Type 2 diabetes is characterized by hyperglycemia and production of glycated proteins. For example, glycated hemoglobin A1c (HbA1c) has been clinically used as diagnostic criteria for diabetes. In addition to glycation, the role of other types of PTMs in type 2 diabetes remains to be revealed. In fact, elevated malonyl-CoA levels have been found in type 2 diabetic patients (12), and prediabetic rats (13). And hepatic overexpression of malonyl-CoA decarboxylase (MCD) decreased malonyl-CoA and reversed insulin resistance (14). Given the use of malonyl-CoA as malonyl donor in lysine malonylation, lysine malonylation is therefore anticipated to be of functional significance in the pathogenesis of type 2 diabetes.In the present study, we observed elevated lysine malonylation in liver tissues of db/db mice after unbiased screening seven types of lysine acylations. We then detected elevated levels of lysine malonylation in liver tissues of more db/db and ob/ob mice. Using an immunoaffinity based proteomic method, we identified a total of 573 malonylated lysine sites from 268 proteins in liver tissues of wt and db/db mice. Elevation of lysine malonylation in five proteins was confirmed by immunoprecipitation coupled with Western blot analysis. Functional analysis of the malonylated proteins showed an apparent enrichment in metabolic pathways, especially those involved in the glucose and fatty acid metabolism. Our study indicates the putative association between protein lysine malonylation and type 2 diabetes.     

鼠神经生长因子对2型糖尿病周围神经病变的影响

目的:探讨鼠神经生长因子治疗2型糖尿病周围神经病变(DPN)临床疗效及安全性。方法:选择89例DPN患者分为观察组45例和对照组44例,两组都给予糖尿病的基础治疗,观察组在基础治疗基础上,加用注射用鼠神经生长因子,对照组加用甲钴胺注射液和丹红注射用,治疗前后测定正中神经和腓总神经的感觉传导速度(SNCV)、运动传导速度(MNCV),行多伦多临床评分系统(TCSS)评分。结果:治疗前,两组患者TCSS评分、正中神经、腓总神经的MNCV及SNCV相似,差异无统计学意义(P0.05);疗程结束时,两组TCSS评分较治疗前均下降,正中神经、腓总神经的MNCV及SNCV较治疗前均增加,差异有统计学意义(P0.05),但是观察组改善幅度较对照组更显著(P0.05)。观察组显效20例、有效23例和无效2例;对照组显效15例、有效21例和无效8例,差异有统计学意义(P0.05)。两组患者治疗期间未见严重不良反应发生。结论:加用鼠神经生长因子可以有效缓解2型糖尿病DPN的临床症状,提高神经传导速度,安全性高。     

Bioluminescence Imaging Reveals Dynamics of Beta Cell Loss in the Non-Obese Diabetic (NOD) Mouse Model

We generated a mouse model (MIP-Luc-VU-NOD) that enables non-invasive bioluminescence imaging (BLI) of beta cell loss during the progression of autoimmune diabetes and determined the relationship between BLI and disease progression. MIP-Luc-VU-NOD mice displayed insulitis and a decline in bioluminescence with age which correlated with beta cell mass, plasma insulin, and pancreatic insulin content. Bioluminescence declined gradually in female MIP-Luc-VU-NOD mice, reaching less than 50% of the initial BLI at 10 weeks of age, whereas hyperglycemia did not ensue until mice were at least 16 weeks old. Mice that did not become diabetic maintained insulin secretion and had less of a decline in bioluminescence than mice that became diabetic. Bioluminescence measurements predicted a decline in beta cell mass prior to the onset of hyperglycemia and tracked beta cell loss. This model should be useful for investigating the fundamental processes underlying autoimmune diabetes and developing new therapies targeting beta cell protection and regeneration.     

Glycemic Control and Diabetic Dyslipidemia in Adolescents with Type 2 Diabetes

ObjectiveThe incidence of type 2 diabetes mellitus (T2DM) is increasing at an alarming rate, especially in ethnic minorities, and T2DM is associated with significant comorbidities. The primary objective of this study was to assess glycemic control and cardiovascular risk outcomes in children with T2DM at 1 year after diagnosis. We also assessed whether insulin treatment at onset of diabetes is beneficial for overall outcome in those with elevated glycated hemoglobin (HbA1C).MethodsA retrospective electronic chart review of non-Hispanic white (NHW) and African American (AA) children with T2DM.ResultsA total of 86 patients (66.3% females, 79.1% AA, mean age, 13.8 ± 2.4 years) with T2DM were included. Analyses of therapeutic outcome measures at the 1-year follow-up showed HbA1C <8% in 27.7% of patients, low-density-lipoprotein cholesterol (LDL-C) >130 mg/dL in 12.5%, non-high-density-lipoprotein cholesterol (non-HDL-C) >160 mg/dL in 15.6%, HDL-C <35 mg/dL in 25%, systolic hypertension (HTN) in 35.6%, and diastolic HTN in 6.8% of subjects. Among those started on insulin at initial diagnosis, there was significant improvement in glycemic outcomes (P<.0001 on insulin vs. P = .02 not on insulin) and dyslipidemia (total cholesterol [TC] [P = .001], LDL-C [P = .02], HDL-C [P = .01], non-HDL-C [P = .0002], and TC/HDL-C [P = .005]) compared with no significant change among those who did not receive insulin at diagnosis.ConclusionSubstantial numbers of children with T2DM do not achieve glycemic and cardiovascular therapeutic goals 1 year after diagnosis. Insulin therapy at diagnosis has significant beneficial effects on diabetic dyslipidemia in those with higher HbA1C. (Endocr Pract. 2013; 19:972-979)     

Diminished Autophagy Limits Cardiac Injury in Mouse Models of Type 1 Diabetes

Cardiac autophagy is inhibited in type 1 diabetes. However, it remains unknown if the reduced autophagy contributes to the pathogenesis of diabetic cardiomyopathy. We addressed this question using mouse models with gain- and loss-of-autophagy. Autophagic flux was inhibited in diabetic hearts when measured at multiple time points after diabetes induction by streptozotocin as assessed by protein levels of microtubule-associated protein light chain 3 form 2 (LC3-II) or GFP-LC3 puncta in the absence and presence of the lysosome inhibitor bafilomycin A1. Autophagy in diabetic hearts was further reduced in beclin 1- or Atg16-deficient mice but was restored partially or completely by overexpression of beclin 1 to different levels. Surprisingly, diabetes-induced cardiac damage was substantially attenuated in beclin 1- and Atg16-deficient mice as shown by improved cardiac function as well as reduced levels of oxidative stress, interstitial fibrosis, and myocyte apoptosis. In contrast, diabetic cardiac damage was dose-dependently exacerbated by beclin 1 overexpression. The cardioprotective effects of autophagy deficiency were reproduced in OVE26 diabetic mice. These effects were associated with partially restored mitophagy and increased expression and mitochondrial localization of Rab9, an essential regulator of a non-canonical alternative autophagic pathway. Together, these findings demonstrate that the diminished autophagy is an adaptive response that limits cardiac dysfunction in type 1 diabetes, presumably through up-regulation of alternative autophagy and mitophagy.     

Oral Administration of Recombinant Lactococcus lactis Expressing HSP65 and Tandemly Repeated P277 Reduces the Incidence of Type I Diabetes in Non-Obese Diabetic Mice

Diabetes mellitus type 1 (DM1) is an autoimmune disease that gradually destroys insulin-producing beta-cells. We have previously reported that mucosal administration of fusion protein of HSP65 with tandem repeats of P277 (HSP65-6P277) can reduce the onset of DM1 in non-obese diabetic (NOD) mice. To deliver large amounts of the fusion protein and to enhance long-term immune tolerance effects, in the present study, we investigated the efficacy of using orally administrated L. lactis expressing HSP65-6P277 to reduce the incidence of DM1 in NOD mice. L. lactis strain NZ9000 was engineered to express HSP65-6P277 either constitutively or by nisin induction. After immunization via gavage with the recombinant L. lactis strains to groups of 4-week old female NOD mice for 36 weeks, we observed that oral administration of recombinant L. Lactis resulted in the prevention of hyperglycemia, improved glucose tolerance and reduced insulitis. Immunologic analysis showed that treatment with recombinant L. lactis induced HSP65- and P277- specific T cell immuno-tolerance, as well as antigen-specific proliferation of splenocytes. The results revealed that the DM1-preventing function was in part caused by a reduction in the pro-inflammatory cytokine IFN-γ and an increase in the anti-inflammatory cytokine IL-10. Orally administered recombinant L. lactis delivering HSP65-6P277 may be an effective therapeutic approach in preventing DM1.     

Diabetic Ketoacidosis in Peruvian Patients with Type 2 Diabetes Mellitus

ObjectiveTo describe the clinical and laboratory characteristics of diabetic ketoacidosis (DKA) in adult Peruvian patients with type 2 diabetes mellitus.MethodsIn this cross-sectional analysis, we reviewed clinical charts of type 2 diabetic patients with DKA admitted to Cayetano Heredia Hospital between 2001 and 2005 for data on demographics, previous treatment, previous hospital admissions for DKA, family history of diabetes, precipitating factors, hospital course, mortality, and insulin use 3 and 6 months after the index DKA episode. Patients older than 18 years who had confirmed DKA were included. Patients with type 1 diabetes mellitus were excluded.ResultsWe report on 53 patients with DKA for whom complete clinical and laboratory data were available. Of the 53 patients, 39 (74%) were men; mean age (± SD) was 45 ± 12 years; and 22 (42%) had no previous diagnosis of type 2 diabetes. The following mean (± SD) laboratory values were obtained at DKA diagnosis: glucose, 457 ± 170 mg/dL; pH, 7.15 ± 0.14; bicarbonate, 7.73 ± 6 mEq/L; and anion gap, 24.45 ± 7.44 mEq/L. Of the 53 DKA episodes, 35 (66%) were severe (arterial pH < 7.0 and/or serum bicarbonate < 10 mEq/L). The following precipitating factors were discerned: discontinuation of treatment in 21 (40%), infections in 16 (30%), intercurrent illness in 3 (6%), and no identifiable cause in 13 (25%). Mortality rate was 0%. Three and 6 months after the index DKA episode, insulin was used by 65% and 56% of patients, respectively.ConclusionIn countries with a low incidence of type 1 diabetes, DKA is frequently reported in patients with type 2 diabetes. In this study, 42% of patients had new-onset disease. Most DKA episodes were severe and were related to infection or noncompliance with treatment. (Endocr Pract. 2008;14:442-446)     

Chronic Kidney Disease and Diabetic Retinopathy in Patients with Type 2 Diabetes

Purpose

To explore the relationship between chronic kidney disease (CKD) and diabetic retinopathy (DR) in a representative population of type 2 diabetes mellitus (DM2) patients in Catalonia (Spain).

Methods

This was a population-based, cross-sectional study. A total of 28,344 patients diagnosed with DM2 who had recorded ophthalmologic and renal functional examinations were evaluated. Data were obtained from a primary healthcare electronic database of medical records. CKD was defined as an estimated glomerular filtration ratio (eGFR) of <60 ml/min/1.73m² and/or urine albumin to creatinine ratio (UACR) ≥30 mg/g. DR was categorized as non-vision threatening diabetic retinopathy and vision threatening diabetic retinopathy.

Results

CKD was associated with a higher rate of DR [OR], 95% confidence interval [CI], 1.5 (1.4–1.7). When we analyzed the association between different levels of UACR and DR prevalence observed that DR prevalence rose with the increase of UACR levels, and this association was significant from UACR values ≥10 mg/g, and increased considerably with UACR values ≥300mg/g (Odds ratio [OR], 95% confidence interval [CI], 2.0 (1.6–2.5). This association was lower in patients with eGFR levels 44 to 30 mL/min/1.73m² [OR], 95% confidence interval [CI], 1.3 (1.1–1.6).

Conclusions

These results show that CKD, high UACR and/or low eGFR, appear to be associated with DR in this DM2 population.     

Genomic and Metabolic Disposition of Non-Obese Type 2 Diabetic Rats to Increased Myocardial Fatty Acid Metabolism

Lipotoxicity of the heart has been implicated as a leading cause of morbidity in Type 2 Diabetes Mellitus (T2DM). While numerous reports have demonstrated increased myocardial fatty acid (FA) utilization in obese T2DM animal models, this diabetic phenotype has yet to be demonstrated in non-obese animal models of T2DM. Therefore, the present study investigates functional, metabolic, and genomic differences in myocardial FA metabolism in non-obese type 2 diabetic rats. The study utilized Goto-Kakizaki (GK) rats at the age of 24 weeks. Each rat was imaged with small animal positron emission tomography (PET) to estimate myocardial blood flow (MBF) and myocardial FA metabolism. Echocardiograms (ECHOs) were performed to assess cardiac function. Levels of triglycerides (TG) and non-esterified fatty acids (NEFA) were measured in both plasma and cardiac tissues. Finally, expression profiles for 168 genes that have been implicated in diabetes and FA metabolism were measured using quantitative PCR (qPCR) arrays. GK rats exhibited increased NEFA and TG in both plasma and cardiac tissue. Quantitative PET imaging suggests that GK rats have increased FA metabolism. ECHO data indicates that GK rats have a significant increase in left ventricle mass index (LVMI) and decrease in peak early diastolic mitral annular velocity (E’) compared to Wistar rats, suggesting structural remodeling and impaired diastolic function. Of the 84 genes in each the diabetes and FA metabolism arrays, 17 genes in the diabetes array and 41 genes in the FA metabolism array were significantly up-regulated in GK rats. Our data suggest that GK rats’ exhibit increased genomic disposition to FA and TG metabolism independent of obesity.     

Diabetes Increases the Expression of Hypothalamic Neuropeptides in a Spontaneous Model of Type I Diabetes, the Nonobese Diabetic (NOD) Mouse

1. Synthesis of oxytocin (OT) and arginine-vasopressin(AVP) is increased in induced models of Type I diabetes, such as thestreptozotocin model. However, these parameters have not yet been evaluated inspontaneous models, such as the nonobese diabetic mouse (NOD). Therefore, we studied in the magnocellular cells of the paraventricular nucleus (PVN)of nondiabetic and diabetic 16-week-old female NOD mice and control C57Bl/6mice, the immunocytochemistry of OT and AVP peptides and their mRNA expression, using nonisotopic in situ hybridization (ISH).2. In nondiabetic and diabetic NOD female mice, the number of OT- and AVP-immunoreactive cells were similar to those of the controls, whereas immunoreaction intensity was significantly higher for both peptides in diabetic NOD as compared with nondiabetic NOD and control C57Bl/6 mice.3. ISH analysis showed that the number of OT mRNA-containing cells was in the same range in the three groups, whereas higher number of AVP mRNA expressing cells was found in diabetic NOD mice. However, the intensity of hybridization signal was also higher for both OT and AVP mRNA in the diabetic group as compared with nondiabetic NOD and control mice.4. Blood chemistry demonstrated that haematrocrit, total plasma proteins, urea, sodium, and potassium were within normal limits in diabetic mice. Thus, NODmice were neither hypernatremic nor dehydrated.5. We suggest that upregulation of OT and AVP reflects a high-stress condition in the NOD mice. Diabetes may affect neuropeptide-producing cells of the PVN, with the increased AVP and OT playing a deleterious role on the outcome of the disease.     

Immunohistochemical Demonstration of Leptin in Pancreatic Islets of Non-Obese Diabetic and CD-1 mice: Co-localization in Glucagon Cells and its Attenuation at the Onset of Diabetes

Leptin is a 16 kD polypeptide hormone produced predominantly by white adipose tissue and exerts profound effects on food intake and energy balance. More recent studies have shown extra sites of leptin production in human and rodent tissues and have ascribed additional roles for the hormone, e.g., in immune and reproductive functions. A role for the hormone has also been implicated in insulin-dependent diabetes mellitus in the non-obese diabetic (NOD) mouse. However, whether leptin originates from islet cells of the mouse is not known. Here dual-label immunohistochemistry was employed to examine leptin expression in islet cells, and its distribution and cellular sources in pancreatic sections of female NOD/Ak and CD-1 mice of various ages. For comparison, leptin immunolabelling was examined in adult pancreatic sections from male NOD/Ak CD-1, Balb/c and FVB/N mice and female severe combined immunodeficient CB. 17 mice. Pancreatic tissues from adult female guinea pig, sheep and cattle and neonatal pigs were also studied. Our results show that in the day 1 NOD and CD-1 mice, leptin immunolabelling was observed in selective glucagon cells within the developing islets while at days 15 and 22, it became more intense and co-incident. This pattern of staining was maintained at days 40, 90, 150 and 250. In the female NOD mouse, leptin was absent in intra-islet immune cells. Its expression was variable in islets from male NOD and CD-1 mice. In spontaneously diabetic female NOD mice and following acceleration of diabetes with cyclophosphamide, despite the persistence of strong immunolabelling for glucagon in the re-distributed alpha cells, leptin expression was either absent, diminished or present in only a proportion of alpha cells. The reduction in leptin labelling was often associated with diabetic islets which had insulitis in association with only a small number of residual beta cells. Leptin expression was absent in guinea pig, ovine, bovine and neonatal porcine islet cells, despite the expression of intensely labelled glucagon cells. The present results demonstrate leptin co-localization in glucagon cells of the mouse islet. Its expression diminishes in the presence of inadequate insulin. Leptin produced within the mouse islet may have bi-directional influences on leptin and insulin regulation and may play local functions in islet development and metabolism.