Early Phase Of Diabetes Research Articles

Short-Term l-arginine Treatment Mitigates Early Damage of Dermal Collagen Induced by Diabetes.

Changes in the structural properties of the skin due to collagen alterations are an important factor in diabetic skin complications. Using a combination of photonic methods as an optic diagnostic tool, we investigated the structural alteration in rat dermal collagen I in diabetes, and after short-term l-arginine treatment. The multiplex approach shows that in the early phase of diabetes, collagen fibers are partially damaged, resulting in the heterogeneity of fibers, e.g., "patchy patterns" of highly ordered/disordered fibers, while l-arginine treatment counteracts to some extent the conformational changes in collagen-induced by diabetes and mitigates the damage. Raman spectroscopy shows intense collagen conformational changes via amides I and II in diabetes, suggesting that diabetes-induced structural changes in collagen originate predominantly from individual collagen molecules rather than supramolecular structures. There is a clear increase in the amounts of newly synthesized proline and hydroxyproline after treatment with l-arginine, reflecting the changed collagen content. This suggests that it might be useful for treating and stopping collagen damage early on in diabetic skin. Our results demonstrate that l-arginine attenuates the early collagen I alteration caused by diabetes and that it could be used to treat and prevent collagen damage in diabetic skin at a very early stage.

Tff3 Deficiency Protects against Hepatic Fat Accumulation after Prolonged High-Fat Diet.

Trefoil factor 3 (Tff3) protein is a small secretory protein expressed on various mucosal surfaces and is involved in proper mucosal function and recovery via various mechanisms, including immune response. However, Tff3 is also found in the bloodstream and in various other tissues, including the liver. Its complete attenuation was observed as the most prominent event in the early phase of diabetes in the polygenic Tally Ho mouse model of diabesity. Since then, its role in metabolic processes has emerged. To elucidate the complex role of Tff3, we used a new Tff3-deficient mouse model without additional metabolically relevant mutations (Tff3-/-/C57BL/6NCrl) and exposed it to a high-fat diet (HFD) for a prolonged period (8 months). The effect was observed in male and female mice compared to wild-type (WT) counter groups (n = 10 animals per group). We monitored the animals’ general metabolic parameters, liver morphology, ultrastructure and molecular genes in relevant lipid and inflammatory pathways. Tff3-deficient male mice had reduced body weight and better glucose utilization after 17 weeks of HFD, but longer HFD exposure (32 weeks) resulted in no such change. We found a strong reduction in lipid accumulation in male Tff3-/-/C57BL/6NCrl mice and a less prominent reduction in female mice. This was associated with downregulated peroxisome proliferator-activated receptor gamma (Pparγ) and upregulated interleukin-6 (Il-6) gene expression, although protein level difference did not reach statistical significance due to higher individual variations. Tff3-/-/C57Bl6N mice of both sex had reduced liver steatosis, without major fatty acid content perturbations. Our research shows that Tff3 protein is clearly involved in complex metabolic pathways. Tff3 deficiency in C57Bl6N genetic background caused reduced lipid accumulation in the liver; further research is needed to elucidate its precise role in metabolism-related events.

Urinary metabolites of type 2 diabetes rats fed with palm oil-enriched high fat diet

High fat diet (HFD) is one of the risk factors of obesity and diabetes. Recommended diet regimen for diabetes is difficult to abide by especially for HFD as it adds flavour to the taste buds. In this study, palm oil-enriched HFD and normal diet were fed to nicotinamide-induced type 2 diabetes rats, respectively for six weeks. Additionally, metformin, a common drug used to treat diabetes was given to rats under treatment groups. We evaluated the change of urinary metabolites of diabetes rats fed with palm oil-enriched HFD, and also after metformin treatment. Rats were divided into six-groups with different feeding diets, disease condition and with or without metformin treatment. Rats’ urine were collected at the end of six weeks feeding program and subjected to 1H-NMR and multivariate data analysis to evaluate their metabolite profiles. At the early phase of diabetes, metabolites changes in diabetic rats were associated with the disease itself. Our data showed that continuous consumption of HFD altered various metabolic pathways of diabetic rats and caused detrimental effects to the rats. On the other hand, metformin treatment combined with normal diet lessened the physiological impacts caused by diabetes condition.

Early combination therapy of empagliflozin and linagliptin exerts beneficial effects on pancreatic \u03b2 cells in diabetic db/db mice

Effects of combination therapy of dipeptidyl peptidase-4 (DPP-4) inhibitor and sodium-glucose co-transporter 2 (SGLT2) inhibitor on β-cells are still unclear, although combination agent of these two drugs has become common in clinical practice. Therefore, we aimed to elucidate the effects of DPP-4 inhibitor and/or SGLT2 inhibitor on β-cell mass and function and compared their effects between in an early and advanced phase of diabetes. We used 7-week-old db/db mice as an early phase and 16-week-old mice as an advanced phase and treated them for 2 weeks with oral administration of linagliptin, empagliflozin, linagliptin + empagliflozin (L + E group), and 0.5% carboxymethylcellulose (Cont group). Blood glucose levels in Empa and L + E group were significantly lower than Cont group after treatment. In addition, β-cell mass in L + E group was significantly larger than Cont group only in an early phase, accompanied by increased Ki67-positive β-cell ratio. In isolated islets, mRNA expression levels of insulin and its transcription factors were all significantly higher only in L + E group in an early phase. Furthermore, mRNA expression levels related to β-cell differentiation and proliferation were significantly increased only in L + E group in an early phase. In conclusion, combination of DPP-4 inhibitor and SGLT2 inhibitor exerts more beneficial effects on β-cell mass and function, especially in an early phase of diabetes rather than an advanced phase.

Urinary Metabolites of Type 2 Diabetes Rats Fed With Palm Oil Enriched-High Fat Diet

High fat diet (HFD) is one of the risk factors to obesity and diabetes. Recommended diet regimen for diabetes is difficult to abide especially for HFD as it adds flavour to the taste buds. In this study, palm oil-enriched HFD and control diet (ND) were fed to nicotinamide-induced type 2 diabetes rats, respectively for six weeks. Additionally, metformin, a common drug used to treat diabetes was given to rats under treatment groups. We evaluated the change of urinary metabolites of diabetes rats caused by HFD, and also after metformin treatment. Rats were divided into six-groups with different feeding diets, disease condition and with or without metformin treatment. Rats’ urine were collected at the end of six weeks feeding program and subjected to 1H-NMR and multivariate data analysis to evaluate their metabolite profiles. At the early phase of diabetes, metabolites changes in diabetic rats were associated with the disease itself. Our data showed that continuous consumption of HFD altered various metabolic pathways of diabetic rats and caused detrimental effects to the rats. Metformin treatment combined with ND lessened the physiological impacts caused by diabetes condition. Funding Information: This research project was supported by USM RUI topdown grant (1001/PFARMASI/870034) funded by Universiti Sains Malaysia. Declaration of Interests: None to declare. Ethics Approval Statement: All experiment procedures were approved by the Animal Ethics Committee Universiti Sains Malaysia (USM/Animal Ethics Approval/2016/(717)).

Dulaglutide exerts beneficial anti atherosclerotic effects in ApoE knockout mice with diabetes: the earlier, the better

There has been no report about the mechanism for anti-atherosclerotic effects of dulaglutide (Dula) and/or about the difference of its effectiveness between in an early and a late phase of diabetes. To address such questions, streptozotocin (STZ) was intraperitoneally injected to ApoE knockout mice at 8 weeks of age. Either Dula or vehicle was administered to STZ-induced diabetic ApoE knockout mice from 10 to 18 weeks of age as an early intervention group and from 18 to 26 weeks as a late intervention group. Next, non-diabetic ApoE knockout mice without STZ injection were subcutaneously injected with either Dula or vehicle. In an early intervention group, atherosclerotic lesion in aortic arch and Mac-2 and CD68-positive areas in aortic root were significantly smaller in Dula group. In abdominal aorta, expression levels of some villain factors were lower in Dula group. In a late intervention group, there were no immunohistological differences in aortic root and expression levels of various factors between two groups. Furthermore, even in non-diabetic ApoE knockout mice, expression levels of inflammatory and macrophage markers were reduced by treatment with Dula. Taken together, Dula exerts more beneficial anti-atherosclerotic effects in an early phase of diabetes rather than in a late phase.

Angiotensin-converting enzyme 2 influences pancreatic and renal function in diabetic mice

AbstractType 1 diabetes is a T-cell mediated autoimmune disease characterized by pancreatic beta cells destruction. Angiotensin-converting enzyme 2 (ACE2), a component of renin–angiotensin system (RAS) has been identified in pancreas from type 2 diabetic mice and its overexpression prevents beta cell dysfunction. We studied the effect of ACE2 deletion on pancreatic and renal function in the nonobese diabetic mice, a model that mimics type 1 diabetes. ACE2-deficient NOD mice and the respective controls were generated. Pancreas function and immunohistochemistry studies were performed. Renal function and RAS gene expression were also analyzed. Renal proximal tubular cells were obtained from these animals to dissect the effect of ACE2 deficiency in these cells. In NOD mice, ACE2 deletion significantly worsened glucose homeostasis, decreased islet insulin content, increased beta cell oxidative stress, and RIPK1-positive islets as compared with control mice. Angiotensin-converting enzyme and angiotensin II type 1 receptor (AT1R) were also increased in ACE2-deficient mice. In kidneys of 30-day diabetic mice, ACE2 deletion decreased podocyte number within the glomeruli, and altered renal RAS gene expression in tubules. ACE2 deletion influenced the expression of fibrosis-related genes in isolated primary renal proximal tubular cells before diabetes onset in NOD mice. Our findings suggest that ACE2 deletion may have a deleterious impact on beta cell and renal function, by promoting oxidative stress and increasing necroptosis mediators. In addition, this effect is accompanied by RAS alterations in both pancreas and renal proximal tubular cells, indicating that ACE2 may exert a renopancreatic protective effect on type 1 diabetes, which is activated before diabetes starts.This study examined the contribution of ACE2 in diabetes onset and the role of ACE2 in the progression of diabetic nephropathy in NOD mouse. ACE2 loss leads to an impaired glucose and insulin homeostasis, RAS activation, increase in oxidative stress, and RIPK1 within the pancreas. In the kidney, ACE2 deletion induced podocyte loss, RAS modulation, and renal fibrosis activation in an early phase of diabetes.

Comparative Histological Study on the Effect of Allium Sativum (Garlic), Allium Cepa (Onion) & Insulin on Lingual Papillae of Diabetic Rats

Introduction: Diabetes mellitus (DM) is a common chronic metabolic disease. Various inflammatory diseases and soft tissue pathologies are associated with DM. Major concern in diabetes is oxidative stress. Antioxidants prevent diabetic complications. Onion & garlic are strong antioxidants, so this study was done to determine their possible effect in minimizing complications that diabetic patients suffer, compared to insulin.Materials and Methods: Fifty Albino rats were divided into 5 groups, ten rats each; Control, untreated streptozotocin induced diabetic group, diabetic insulin treated, diabetic garlic treated and diabetic onion treated groups. On the 21st day of the experiment, rats were sacrificed and tongue specimens were prepared and examined by H&E for routine histological examination and by scanning Electron Microscope.Results: Histological changes of tongue papillae of diabetic untreated rats were observed, such as thinning of the epithelium of all papillae, numerous intra-epithelial cell vacuolations, thin detached keratin, extrcellular edema and inflammatory cell infiltrate within the lamina properia of all papillae. After, administration of insulin, garlic and onion, tongue papillae appeared almost normal compared to control group. However, the onion group displayed apparently slight better morphological and structural findings than garlic group.Discussion: Circumvallate papillae were most affected may be due to difference in their gustatory nerve supply. Other papillae in both garlic and onion treated groups, appeared almost normal. Which can be explained by the hypoglycemic, antimicrobial, anti-inflammatory effect of both extracts.Conclusion: Garlic and onion oral intake during early phases of diabetes caused valuable improvement of tongue papillae which was highly comparable to insulin treatment.

1435-P: Dulaglutide Exerts More Beneficial Antiatherosclerotic Effects in Early Phase of Diabetes than in Late Phase in ApoE Knockout Mice with Diabetes

There is no report about the anti-atherosclerotic effects of GLP-1 receptor activator dulaglutide (Dula) and the difference of its effectiveness between intervention from early phase and late phase of diabetes. Therefore, we aimed to address such questions by using ApoE knockout mice. First, ApoE KO mice without diabetes were subcutaneously injected with either Dula (0.6mg/kg×2/week) or vehicle from 10 to 18 weeks of age. No significant differences in blood glucose, serum lipid levels, body weight and atherosclerotic lesion of aortic arch were observed between two groups. In abdominal aorta, mRNA expression levels of V-CAM, F4/80, MCP-1, IL-6 and TNF-α were significantly lower in Dula group. Second, streptozotocin (50mg/kg×5days) was intraperitoneally injected to ApoE KO mice at 8 weeks of age. Animals whose non-fasting glucose levels were over 300 mg/dL underwent experiments. Either Dula or vehicle was administered to ApoE KO mice with diabetes from 10 to 18 weeks of age. Atherosclerotic lesion of aortic arch in Dula group was significantly smaller compared with vehicle group. CD68-positive area of aortic root was significantly smaller in Dula group. In abdominal aorta, mRNA expression level of GLP-1 receptor was significantly higher, while mRNA expression levels of MCP-1, IL-6, F4/80 and CD68 were significantly lower in Dula group. Finally, ApoE KO mice with diabetes received Dula or vehicle from 18 to 26 weeks of age. Atherosclerotic lesion of aortic arch in Dula group was significantly smaller compared with vehicle group. However, no differences were observed in immunostaining of aortic root and mRNA expression levels of various factors in abdominal aorta. In conclusion, Dula improved mRNA expressions of inflammatory and macrophage markers in a glucose-independent manner. Furthermore, our data suggest Dula exerts more beneficial anti-atherosclerotic effects in early phase of diabetes than in late phase. Disclosure J. Sanada: None. A. Obata: None. Y. Obata: None. Y. Fushimi: None. T. Ikeda: None. Y. Nogami: None. M. Shimoda: None. S. Nakanishi: None. T. Mune: None. K. Kaku: Advisory Panel; Self; Nippon Boehringer Ingelheim Co. Ltd., Novo Nordisk Inc. Consultant; Self; Sanwa Kagaku Kenkyusho. Research Support; Self; Taisho Pharmaceutical Co., Ltd. Speaker’s Bureau; Self; Astellas Pharma Inc., AstraZeneca, Daiichi Sankyo, Eli Lilly Japan K.K., Kowa Company, Ltd., Merck Sharp & Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Ono Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited. H. Kaneto: Research Support; Self; Astellas Pharma Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo, Eli Lilly Japan K.K., Kissei Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi, Sumitomo Dainippon Pharma Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited. Speaker’s Bureau; Self; Astellas Pharma Inc., AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo, Eli Lilly Japan K.K., Mitsubishi Tanabe Pharma Corporation, Novartis Pharmaceuticals Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi, Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Company Limited.

2054-P: Combination of Dipeptidyl Peptidase-4 (DPP-4) Inhibitor and Sodium–Glucose Cotransporter 2 (SGLT2) Inhibitor Substantially Protects Pancreatic ß-Cells Especially in Early Phase of Diabetes Rather than Advanced Phase

In diabetes treatment, it is important to protect pancreatic β-cells in addition to correct hyperglycemia. Although DPP-4 inhibitor and SGLT2 inhibitor are widely used nowadays, there is no report about β-cell protective effect by combination of both inhibitors. In this study, we examined the effects of DPP-4 inhibitor and/or SGLT2 inhibitor on β-cells and compared their effects between in early and advanced phase of diabetes. We used 7-week-old BKS. Cg-+ Leprdb/Jcl (db/db) mice as early phase and 16-week-old mice as advanced phase, and treated them for 2 weeks with oral administration of linagliptin 3 mg/kg (Lina group), empagliflozin 30mg/kg (Empa group), linagliptin + empagliflozin (L+E group), and 0.5% carboxymethylcellulose (Cont gourp). After 2-week treatment, blood glucose levels in Empa and L+E group were significantly lower than Cont group. OGTT after 1-week treatment showed that blood glucose levels were significantly lower in Empa and L+E group in both phases, and slightly lower in Lina group only in early phase. After 2-week treatment, islets size in L+E group was significantly larger than Cont group only in early phase. In GSIS using isolated islets, insulin levels in Lina, Empa and L+E group were significantly higher than Cont group in both phases. Furthermore, mRNA expression levels of ins1, ins2 and their transcription factors mafa, pdx-1, neurod and nkx6.1 were all higher in Lina and L+E group in early phase. Contrarily, mRNA expression levels of caspase3, 8 were lower in Lina and L+E group, and jnk and c-jun levels were lower in Empa and L+E group in early phase. Intriguingly, such changes were not observed in advanced phase. It seemed that DPP-4 inhibitor and SGLT2 inhibitor exerted beneficial effects on β-cells through some different mechanism. In conclusion, combination of DPP-4 inhibitor and SGLT2 inhibitor protects β-cells in early phase of diabetes. Disclosure Y. Fushimi: None. A. Obata: None. J. Sanada: None. Y. Nogami: None. T. Ikeda: None. Y. Obata: None. M. Shimoda: None. S. Nakanishi: None. T. Mune: None. K. Kaku: Advisory Panel; Self; Nippon Boehringer Ingelheim Co. Ltd., Novo Nordisk Inc. Consultant; Self; Sanwa Kagaku Kenkyusho. Research Support; Self; Taisho Pharmaceutical Co., Ltd. Speaker’s Bureau; Self; Astellas Pharma Inc., AstraZeneca, Daiichi Sankyo, Eli Lilly Japan K.K., Kowa Company, Ltd., Merck Sharp & Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Ono Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited. H. Kaneto: Research Support; Self; Astellas Pharma Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo, Eli Lilly Japan K.K., Kissei Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi, Sumitomo Dainippon Pharma Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited. Speaker’s Bureau; Self; Astellas Pharma Inc., AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo, Eli Lilly Japan K.K., Mitsubishi Tanabe Pharma Corporation, Novartis Pharmaceuticals Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi, Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Company Limited.

Conditions, pathogenesis, and progression of diabetic kidney disease and early decliner in Japan

ObjectiveGlomerular filtration rate (GFR) decreases without or prior to the development of albuminuria in many patients with diabetes. Therefore, albuminuria and/or a low GFR in patients with diabetes is referred...

Effect of Tff3 Deficiency and ER Stress in the Liver.

Endoplasmic reticulum (ER) stress, a cellular condition caused by the accumulation of unfolded proteins inside the ER, has been recognized as a major pathological mechanism in a variety of conditions, including cancer, metabolic and neurodegenerative diseases. Trefoil factor family (TFFs) peptides are present in different epithelial organs, blood supply, neural tissues, as well as in the liver, and their deficiency has been linked to the ER function. Complete ablation of Tff3 expression is observed in steatosis, and as the most prominent change in the early phase of diabetes in multigenic mouse models of diabesity. To elucidate the role of Tff3 deficiency on different pathologically relevant pathways, we have developed a new congenic mouse model Tff3−/−/C57BL6/N from a mixed background strain (C57BL6/N /SV129) by using a speed congenics approach. Acute ER stress was evoked by tunicamycin treatment, and mice were sacrificed after 24 h. Afterwards the effect of Tff3 deficiency was evaluated with regard to the expression of relevant oxidative and ER stress genes, relevant proinflammatory cytokines/chemokines, and the global protein content. The most dramatic change was noticed at the level of inflammation-related genes, while markers for unfolded protein response were not significantly affected. Ultrastructural analysis confirmed that the size of lipid vacuoles was affected as well. Since the liver acts as an important metabolic and immunological organ, the influence of Tff3 deficiency and physiological function possibly reflects on the whole organism.

568-P: Pain Threshold of Intraepidermal Nerve Terminal Reflects Small Nerve Fiber Function and Rises in Early Phase of Diabetes

We measured pain threshold of intra-epidermal nerve terminal (PINT) which is a simple and noninvasive method that can measure pain threshold of A delta fiber by intra-epidermal electrical stimulation. We aimed to investigate normal value, prevalence of abnormality and clinically associated factors to PINT and quantitative vibratory perception threshold (QVT). PINT and QVT were measured by a portable peripheral nerve testing device PNS-7000, and a vibration sensation meter AU 02-B in 656 Japanese regional health checkup examinees (40-75 years old; years old). Glucose tolerance; normal (N), pre-DM, newly diagnosed DM (NDM) and known DM (KDM), and neuropathic findings (pain, paresthesia, numbness in legs and reduced ATRs) were also determined. Relationship between age, glucose tolerance, neuropathic findings and PINT or QVT were investigated by simple and multivariate analyses. In 445 non-DM subjects without neuropathic findings, normal limit value of PINT (mA) was set by quantile regression method, and relationship between prevalence of PINT or QVT abnormalities and clinical factors were examined. As results, PINT was not changed under 70 years old, then somewhat elevated. QVT elevated from 50 years old. PINT was not associated with QVT. PINT was significantly elevated in NDM and KDM. QVT was elevated in diabetes and hypertension. Among the neuropathic findings, PINT was significantly associated with only pain. By multiple regression analyses, significant aggravating factors of PINT were aging and glucose intolerance. Normal values of PINT were > 0.4 (<69 years old) and >0.5 (70< years old) Prevalence of PINT abnormality were 3%, 4%, 13% and 9% in N, pre-DM, NDM and KDM, respectively. They were significantly increased with the deterioration of glucose tolerance. QVT abnormality was not significantly increased with glucose intolerance. In conclusion, PINT reflects small nerve fiber function, and associates with DM. So, PINT may be a useful for diagnosis and evaluation of small fiber neuropathy. Disclosure H. Sasaki: None. S. Kishimoto: None. K. Ogawa: None. S. Kurisu: None. K. Nanjo: None. Funding Japan Society for the Promotion of Science

Tadalafil, a phosphodiesterase type 5 inhibitor, improves bladder blood supply and restores the initial phase of lower urinary tract dysfunction in diabetic rats.

To investigate the effect of tadalafil on bladder blood flow and lower urinary tract function in a rat model of diabetes. We studied female Sprague-Dawley rats and induced diabetes in some using a single intraperitoneal injection of streptozotocin. We divided the rats into nondiabetes (ND), diabetes (D), and diabetes with tadalafil (DT) groups. The rats were raised for an additional 7 weeks after diabetes induction. The DT group received oral tadalafil (2 mg/kg/day) for 7 days before the experiments. At 7 weeks after diabetes induction, we performed cystometry, resected the bladders for immunohistochemistry (hypoxia-inducible factor-1α [HIF-1α] and 8-oxo-2'-deoxyguanosine [8-OHdG] staining), and measured bladder blood supply using a laser blood flow meter. The opening pressure, when the urethra opens and urine flow starts, was significantly lower in the DT group than in the D group (24.9 ± 5.9 vs 43.6 ± 12.3 cmH2 O). The inter-contraction interval was significantly longer in the D group than in the ND and DT groups (1566.2 ± 168.7 vs 702.9 ± 165.2 and 787.4 ± 148.8 s). Immunohistochemistry showed positive staining of the urothelial layer for both HIF-1α and 8-OHdG in the D group, but not in the ND or DT groups. Bladder blood flow was significantly lower in the D group than in the ND or DT groups. Tadalafil improves bladder blood supply and lower urinary tract function in diabetic rats. Tadalafil may be a promising drug that restores lower urinary tract dysfunction in the early phase of diabetes.

Advanced glycation end products induce brain-derived neurotrophic factor release from human platelets through the Src-family kinase activation

BackgroundBrain-derived neurotrophic factor (BDNF) exerts beneficial effects not only on diabetic neuropathies but also on cardiovascular injury. There is argument regarding the levels of serum BDNF in patients with diabetes mellitus (DM). Because BDNF in peripheral blood is rich in platelets, this may represent dysregulation of BDNF release from platelets. Here we focused on advanced glycation end products (AGEs), which are elevated in patients with DM and have adverse effects on cardiovascular functions. The aim of this study is to elucidate the role of AGEs in the regulation of BDNF release from human platelets.MethodsPlatelets collected from peripheral blood of healthy volunteers were incubated with various concentrations of AGE (glycated-BSA) at 37 °C for 5 min with or without BAPTA-AM, a cell permeable Ca2+ chelator, or PP2, a potent inhibitor of Src family kinases (SFKs). Released and cellular BDNF were measured by ELISA and calculated. Phosphorylation of Src and Syk, a downstream kinase of SFKs, in stimulated platelets was examined by Western blotting and immunoprecipitation.ResultsAGE induced BDNF release from human platelets in a dose-dependent manner, which was dependent on intracellular Ca2+ and SFKs. We found that AGE induced phosphorylation of Src and Syk.ConclusionsAGE induces BDNF release from human platelets through the activation of the Src-Syk-(possibly phospholipase C)-Ca2+ pathway. Considering the toxic action of AGEs and the protective roles of BDNF, it can be hypothesized that AGE-induced BDNF release is a biological defense system in the early phase of diabetes. Chronic elevation of AGEs may induce depletion or downregulation of BDNF in platelets during the progression of DM.

Interferon-α mediates human beta cell HLA class I overexpression, endoplasmic reticulum stress and apoptosis, three hallmarks of early human type 1 diabetes.

Three hallmarks of the pancreatic islets in early human type 1 diabetes are overexpression of HLA class I, endoplasmic reticulum (ER) stress and beta cell apoptosis. The mediators of these phenomena remain to be defined. The type I interferon IFNα is expressed in human islets from type 1 diabetes patients and mediates HLA class I overexpression. We presently evaluated the mechanisms involved in IFNα-induced HLA class I expression in human beta cells and determined whether this cytokine contributes to ER stress and apoptosis. IFNα-induced inflammation, ER stress and apoptosis were evaluated by RT-PCR, western blot, immunofluorescence and nuclear dyes, and proteins involved in type I interferon signalling were inhibited by small interfering RNAs. All experiments were performed in human islets or human EndoC-βH1 cells. IFNα upregulates HLA class I, inflammation and ER stress markers in human beta cells via activation of the candidate gene TYK2, and the transcription factors signal transducer and activator of transcription 2 and IFN regulatory factor 9. Furthermore, it acts synergistically with IL-1β to induce beta cell apoptosis. The innate immune effects induced by IFNα may induce and amplify the adaptive immune response against human beta cells, indicating that IFNα has a central role in the early phases of diabetes.

Administration of Zinc plus Cyclo-(His-Pro) Increases Hippocampal Neurogenesis in Rats during the Early Phase of Streptozotocin-Induced Diabetes.

The effects of zinc supplementation on hippocampal neurogenesis in diabetes mellitus have not been studied. Herein, we investigated the effects of zinc plus cyclo-(His-Pro) (ZC) on neurogenesis occurring in the subgranular zone of dentate gyrus after streptozotocin (STZ)-induced diabetes. ZC (27 mg/kg) was administered by gavage once daily for one or six weeks from the third day after the STZ injection, and histological evaluation was performed at 10 (early phase) or 45 (late phase) days after STZ injection. We found that the proliferation of progenitor cells in STZ-induced diabetic rats showed an increase in the early phase. Additionally, ZC treatment remarkably increased the number of neural progenitor cells (NPCs) and immature neurons in the early phase of STZ-induced diabetic rats. Furthermore, ZC treatment showed increased survival rate of newly generated cells but no difference in the level of neurogenesis in the late phase of STZ-induced diabetic rats. The present study demonstrates that zinc supplementation by ZC increases both NPCs proliferation and neuroblast production at the early phase of diabetes. Thus, this study suggests that zinc supplemented with a histidine/proline complex may have beneficial effects on neurogenesis in patients experiencing the early phase of Type 1 diabetes.

13C-Acetic Acid Breath Test Monitoring of Gastric Emptying during Disease Progression in Diabetic Rats.

Gastric motility disturbance is commonly found in long-standing hyperglycemia. Both delayed and rapid gastric emptying has been reported in diabetes. However, very few studies have followed the changes in gastric emptying during disease progression in diabetes because of technical limitations. 13C-Acetic acid breath test is a validated method which is non-invasive and can be used repeatedly or serially to evaluate gastric emptying changes in animal. We investigated the gastric emptying changes in different stages of diabetes using 13C-acetic acid breath test, as well as its related mechanisms involving interstitial cells of Cajal (ICCs), and stem cell factor (SCF) in streptozotocin-induced diabetic rats. The results showed that gastric emptying was accelerated at the early stage (12 weeks of diabetes) whereas intramuscular ICCs (ICC-IM) networks were not different from normal group. At long-term stage (28 weeks of diabetes), gastric emptying had returned to normal pattern with no delayed. ICC-IM networks were decreased in the diabetic group compared to 12th weeks, and were lower than in the normal group at the same time point. SCF levels were constantly high in the diabetic group than in the normal group. This result indicated that 13C-acetic acid breath test is useful to track the alteration in gastric emptying during disease progression. The change of gastric emptying was not found to be significantly associated with ICC-IM. Elevated SCF may help to preserve ICC-IM, especially in the early phase of diabetes.

Correlation of level of TNF -α with severity of Diabetic Polyneuropathy in Type-2 Diabetes Mellitus

Diabetic poly neuropathy (DPN) is the most common chronic complication of type 2 diabetes. Aim of this observational cross sectional study is to establish correlation between level of TNF α and severity of DPN if any. The forty seven subjects were divided into three groups. Group1:15 healthy normal controls; Group2:12 T2DM patients without neuropathy controls; Group3:20 T2DM patients with painful neuropathy case. To measure TNF-α 5ml blood was drawn and centrifuged and then TNF-α measurement was done with Ray Bio Human TNF-α ELISA kit. Plasma TNF-α shows high correlation with progress of neuropathy; In early phases of diabetes (group2) TNF-α shows a tendency to rise, which increases further with development of overt painful neuropathy (group3).

Alterations of voltage-dependent K(+) channels in the mesenteric artery during the early and chronic phases of diabetes.

This study investigated the alteration of voltage-dependent K(+) (Kv) channels in mesenteric arterial smooth muscle cells from control (Long-Evans Tokushima Otsuka [LETO]) and diabetic (Otsuka Long-Evans Tokushima Fatty [OLETF]) rats during the early and chronic phases of diabetes. We demonstrated alterations in the mesenteric Kv channels during the early and chronic phase of diabetes using the patch-clamp technique, the arterial tone measurement system, and RT-PCR in Long-Evans Tokushima (LETO; for control) and Otsuka Long-Evans Tokushima Fatty (OLETF; for diabetes) type 2 diabetic model rats. In the early phase of diabetes, the amplitude of mesenteric Kv currents induced by depolarizing pulses was greater in OLETF rats than in LETO rats. The contractile response of the mesenteric artery induced by the Kv inhibitor, 4-aminopyridine (4-AP), was also greater in OLETF rats. The expression of most Kv subtypes- including Kv1.1, Kv1.2, Kv1.4, Kv1.5, Kv1.6, Kv2.1, Kv3.2, Kv4.1, Kv4.3, Kv5.1, Kv6.2, Kv8.1, Kv9.3, and Kv10.1-were increased in mesenteric arterial smooth muscle from OLETF rats compared with LETO rats. However, in the chronic phase of diabetes, the Kv current amplitude did not differ between LETO and OLETF rats. In addition, the 4-AP-induced contractile response of the mesenteric artery and the expression of Kv subtypes did not differ between the two groups. The increased Kv current amplitude and Kv channel-related contractile response were attributable to the increase in Kv channel expression during the early phase of diabetes. The increased Kv current amplitude and Kv channel-related contractile response were reversed during the chronic phase of diabetes.