The relationship between bile acid concentration, glucagon-like-peptide 1, fibroblast growth factor 15 and bile acid receptors in rats during progression of glucose intolerance.

BACKGROUND: Recent studies show that bile acids are involved in glucose and energy homeostasis through activation of G protein coupled membrane receptor (TGR5) and farnesoid X receptor (FXR). A few researches have explored changes of TGR5 and FXR in animals with impaired glucose regulation. This study aimed to observe changes of plasma total bile acids (TBA), glucagon-like-peptide 1 (GLP-1), fibroblast growth factor 15 (FGF15), intestinal expressions of TGR5 and FXR, and correlations between them in rats with glucose intolerance. METHODS: Besides plasma fasting glucose, lipid, TBAs, alanine transaminase (ALT), active GLP-1(GLP-1A) and FGF15, a postprandial meal test was used to compare responses in glucose, insulin and GLP-1A among groups. The expressions of TGR5 and FXR in distal ileum and ascending colon were quantified by real-time PCR and western blot. RESULTS: TGR5 expression was significantly decreased in distal ileum in DM group compared to other groups, and TGR5 and FXR expressions in ascending colon were also decreased in DM group compared to other groups. Correlation analysis showed correlations between TBA and GLP-1A or FGF15. GLP-1A was correlated with TGR5 mRNA expression in colon, and FGF15 was correlated with FXR mRNA expression in colon. CONCLUSIONS: These results indicates that bile acid-TGR5/FXR axis contributes to glucose homeostasis.

Human umbilical cord mesenchymal stem cells attenuate diabetic nephropathy through the IGF1R-CHK2-p53 signalling axis in male rats with type 2 diabetes mellitus. / 人脐带间å 质干细胞通过IGF1R-CHK2-p53信号轴减轻2åž‹ç³–å°¿ç— é›„æ€§å¤§é¼ ç³–å°¿ç— è‚¾ç— .

Diabetes mellitus (DM) is a disease syndrome characterized by chronic hyperglycaemia. A long-term high-glucose environment leads to reactive oxygen species (ROS) production and nuclear DNA damage. Human umbilical cord mesenchymal stem cell (HUcMSC) infusion induces significant antidiabetic effects in type 2 diabetes mellitus (T2DM) rats. Insulin-like growth factor 1 (IGF1) receptor (IGF1R) is important in promoting glucose metabolism in diabetes; however, the mechanism by which HUcMSC can treat diabetes through IGF1R and DNA damage repair remains unclear. In this study, a DM rat model was induced with high-fat diet feeding and streptozotocin (STZ) administration and rats were infused four times with HUcMSC. Blood glucose, interleukin-6 (IL-6), IL-10, glomerular basement membrane, and renal function were examined. Proteins that interacted with IGF1R were determined through coimmunoprecipitation assays. The expression of IGF1R, phosphorylated checkpoint kinase 2 (p-CHK2), and phosphorylated protein 53 (p-p53) was examined using immunohistochemistry (IHC) and western blot analysis. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum levels of 8-hydroxydeoxyguanosine (8-OHdG). Flow cytometry experiments were used to detect the surface markers of HUcMSC. The identification of the morphology and phenotype of HUcMSC was performed by way of oil red "O" staining and Alizarin red staining. DM rats exhibited abnormal blood glucose and IL-6/10 levels and renal function changes in the glomerular basement membrane, increased the expression of IGF1 and IGF1R. IGF1R interacted with CHK2, and the expression of p-CHK2 was significantly decreased in IGF1R-knockdown cells. When cisplatin was used to induce DNA damage, the expression of p-CHK2 was higher than that in the IGF1R-knockdown group without cisplatin treatment. HUcMSC infusion ameliorated abnormalities and preserved kidney structure and function in DM rats. The expression of IGF1, IGF1R, p-CHK2, and p-p53, and the level of 8-OHdG in the DM group increased significantly compared with those in the control group, and decreased after HUcMSC treatment. Our results suggested that IGF1R could interact with CHK2 and mediate DNA damage. HUcMSC infusion protected against kidney injury in DM rats. The underlying mechanisms may include HUcMSC-mediated enhancement of diabetes treatment via the IGF1R-CHK2-p53 signalling pathway.

Association between circulating oxidized OxLDL/LDL-C ratio and the severity of coronary atherosclerosis, along with other emerging biomarkers of cardiovascular disease in patients with type 2 diabetes.

AIMS: The aim of this study was to evaluate the association between circulating oxLDL/LDL-C ratio and the severity of coronary atherosclerosis, along with other emerging biomarkers of cardiovascular disease (CVD) in patients with type 2 diabetes. METHODS: We recruited 152 patients with type 2 diabetes for our study. ELISA measured the plasma levels of oxLDL and other biomarkers. The severity of coronary lesions was evaluated using Gensini scores, which were calculated based on results of coronary computed tomographic angiography (CCTA). All patients were allocated into four groups according to CCTA findings and Gensini score: normal group (score = 0), mild coronary atherosclerosis group (0 < scores ≤ 3), moderate coronary atherosclerosis group (3.01 ≤ scores ≤ 32.67) and severe coronary atherosclerosis group (32.68 ≤ scores ≤ 180). Association between the oxLDL/LDL-C ratio and the severity of coronary atherosclerosis were evaluated using logistic regression models. RESULTS: Multivariate logistic regression analysis showed that the oxLDL/LDL-C ratio was positively associated with severity of coronary atherosclerosis (OR 2.03, 95% CI 1.31-3.14, p < 0.01). Interleukin 33 (IL33) correlated positively with oxLDL/LDL-C ratio (r = 0.274, p < 0.01). However, vascular cell adhesion molecular-1 (VCAM-1) had similar trends with oxLDL/LDL-C ratio in these 4 groups. CONCLUSIONS: OxLDL/LDL-C ratio is considered as a potential biomarker in patients with diabetes for early recognition and intervention of severe coronary atherosclerosis, and will be more effective if tested IL33 and VCAM-1 at the same time.

Effects of GLP-1 receptor analogue liraglutide and DPP-4 inhibitor vildagliptin on the bone metabolism in ApoE-/- mice.

BACKGROUND: It has been reported that glucagon-like peptide-1 (GLP-1) can alleviate diabetic osteoporosis (DOP). This study was to investigate the effects of GLP-1RA liraglutide and dipeptidyl peptdase-4 (DPP-4) inhibitor vildagliptin on the advanced glycation end products (AGEs)-induced bone injury in ApoE-/- mice with euglycemia. METHODS: The bone markers OC, PINP, PTH, TRACP and CTX, the mRNA and protein expressions of RAGE in the femur, and the femoral morphology index were determined to evaluate whether the osteoporosis was improved by liraglutide or vildagliptin. RESULTS: AGEs adversely affected the bone metabolism, characterized by reduced OC and increased CTX. However, vildagliptin reduced AGEs and increased OC, and liraglutide significantly decreased AGEs and PTH. Both vildagliptin and liraglutide had no effects on the bone metrology and RAGE expression in the femurs of ApoE-/- mice. CONCLUSIONS: The elevated AGEs may exacerbate osteogenesis and increase bone resorption, and vildagliptin/liraglutide may improve bone metabolism.

Peripheral pain is enhanced by insulin-like growth factor 1 and its receptors in a mouse model of type 2 diabetes mellitus.

BACKGROUND: Insulin-like growth factor 1 (IGF1) is a neurotrophic factor with many actions, including a possible hyperalgesic effect. This study investigated the effects of IGF1 on the overall behavior of diabetic mice and explored the possible mechanisms underlying IGF1-induced pain. METHODS: Mice were divided into five groups (db/m, db/db, vehicle-treated db/db, IGF1-treated db/db, and IGF1 + JB1-treated db/db mice). Behavioral studies were conducted using the hot plate and Von Frey tests after intraplantar injection of recombinant (r) IGF1 (50 µg/kg) and the IGF1 receptor (IGF1R) antagonist JB1 (6 µg/mouse). Morphological changes in dorsal root ganglia (DRG) were evaluated using electron microscopy. Immunofluorescence was used to detect IGF1R expression and colocalisation with pain mediators in the DRG. Changes in the expression of IGF1R, extracellular signal-regulated kinase (ERK), and ras-associated factor-1 (c-raf) in the DRG were evaluated using western blotting. RESULTS: Intraplantar injection of rIGF1 resulted in a hyperalgesic effect after 2 hours. This IGF1-induced hypersensitivity was attenuated by prior intraplantar injection of the IGF1R antagonist. There was no significant change in neuronal structure in the db/m group, whereas neuronal structure was impaired in the other four groups. Moreover, IGF1R was colocalised with pain mediators in the DRG of mice. Intraplantar injection of rIGF1 resulted in increased IGF1R, phosphorylated (p-) ERK, and c-raf expression in the DRG; prior intraplantar injection of the IGF1R antagonist attenuated rIGF1-induced increases in p-ERK and c-raf. CONCLUSIONS: The results indicate that IGF1-induced acute hyperalgesia may be associated with the IGF1R/c-raf/ERK pathway. The IGF1-induced hypersensitivity was attenuated by an IGF1R antagonist.

Efficacy and Safety of Premixed Human Insulin Combined with Sulfonylureas in Type 2 Diabetic Patients Previously Poorly Controlled with Insulin.

INTRODUCTION: Some type 2 diabetes (T2DM) patients treated with premixed insulin alone or in combination with oral glucose-lowering agents (without sulfonylureas) cannot reach the required glucose targets. Clinical studies have demonstrated that diabetes patients treated with sulfonylureas achieve stable glycemic control, with a low hypoglycemic rate. The aim of our study was to evaluate the efficacy and safety of therapy with the combination of premixed insulin and sulfonylureas. METHODS: A total of 120 patients with T2DM who were unable to achieve glycemic control on premixed human insulin were randomized into four groups, namely, a control group (premixed human insulin only) and three groups receiving combination therapy with premixed human insulin and one of the following sulfonylureas: gliclazide sustained release tablets [Diamicron], glipizide extended release tablets [Glucotrol XL], and glimepiride medium-to-long-acting tablets [Amaryl], with 30 patients in each group. Hemoglobin A1c, blood glucose, and adverse events were assessed at baseline and at the end of the 12-week treatment period. RESULTS: After treatment for 12 weeks, HbA1c, fasting glucose, and 2-h postprandial glucose levels in the four groups were significantly decreased when compared with baseline (P < 0.05). However, there was no difference between the four groups at the end of the study. In the control group, the daily insulin dose had been significantly increased at the end of the follow-up when compared with baseline (P < 0.05), while there were no significant changes in premixed insulin dose in the three combination therapy groups. There were no significant differences in adverse events among the four groups. CONCLUSION: Insulin combined with sulfonylureas could improve glycemic control without increasing daily insulin dose and adverse events. Based on our results, we consider the combination of premixed insulin and sulfonylureas to be effective and safe for the treatment of T2DM. TRIAL REGISTRATION: This trial was registered as ChiCTR-TRC-14004751. Trial Registration Date: 5 June 2014.

Effects of mobile phone application combined with or without self-monitoring of blood glucose on glycemic control in patients with diabetes: A randomized controlled trial.

AIMS/INTRODUCTION: There is potential for mobile applications to deliver new self-management interventions for chronic disease, especially in diabetes. The aim of the present study was to evaluate the effects of a mobile phone application (MPA) combined with or without self-monitoring of blood glucose (SMBG) on glycemic control in patients with diabetes. MATERIALS AND METHODS: The study was a 24-week period, four-arm parallel group, non-blinded, randomized trial. A total of 185 patients with mean age of 52 years were randomized to group A (no MPA and no SMBG), group B (SMBG only), group C (MPA only) and group D (both MPA and SMBG were used). Changes in glycated hemoglobin (HbA1c), fasting plasma glucose and 1,5-anhydroglucitol from baseline to week 24 were analyzed. RESULTS: At 24 weeks, the HbA1c levels in patients of all groups decreased significantly from baseline. There were significant differences in the proportions of patients that achieved HbA1c <7% between groups, especially in group C and group D, compared with group A at week 24 (60.4%, 62.2% vs 25.5%, all P < 0.05). 1,5-Anhydroglucitol changes were obvious in group A and group C at week 24 from baseline (all P < 0.05 within groups). Factorial analysis of anova showed that MPA intervention was the main effective factor for HbA1c change (F = 4.59, P = 0.034), and there was no effect on HbA1c change for SMBG intervention (P = 0.975). CONCLUSIONS: Implementation of the MPA, Diabetes-Carer, is effective in improving the proportion of HbA1c <7% in patients with type 2 diabetes.

Protection of insulin­like growth factor 1 on experimental peripheral neuropathy in diabetic mice.

The present study investigated whether insulin­like growth factor­1 (IGF­1) exerts a protective effect against neuropathy in diabetic mice and its potential underlying mechanisms. Mice were divided into four groups: Db/m (control), db/db (diabetes), IGF­1­treated db/db and IGF­1­picropodophyllin (PPP)­treated db/db. Behavioral studies were conducted using the hot plate and von Frey methods at 6 weeks of age prior to treatment. The motor nerve conduction velocity (NCV) of the sciatic nerve was measured using a neurophysiological method at 8 weeks of age. The alterations in the expression levels of IGF­1 receptor (IGF­1R), c­Jun N­terminal kinase (JNK), extracellular signal­regulated kinase (ERK), p38 and effect of IGF­1 on the sciatic nerve morphology were observed by western blotting and electron microscopy. Compared with the control group, the diabetes group developed hypoalgesia after 12 weeks, and neurological lesions improved following an intraperitoneal injection of recombinant (r)IGF­1. The sciatic NCV in the diabetes group was significantly lower compared with the control group. The sciatic NCV improved following rIGF­1 intervention; however, was impaired following administration of the IGF­1 receptor antagonist, PPP. The myelin sheath in the sciatic nerve of the diabetes group was significantly more impaired compared with the control group. The myelin sheath in the sciatic nerves of the rIGF­1­treated group was significantly improved compared with the diabetes group; whereas, they were significantly impaired following administration of the IGF­1R inhibitor. In addition, the expression of IGF­1R, phosphorylated (p)­JNK and p­ERK of sciatic nerves in the db/db mice was significantly increased following treatment with IGF­1. The expression levels of these proteins were significantly lower in the IGF­1­PPP group compared with the IGF­1 group; however, no significant difference was observed in the expression levels of p­p38 following treatment with IGF­1. The results of the present study demonstrated that IGF­1 may improve neuropathy in diabetic mice. This IGF­1­induced neurotrophic effect may be associated with the increased phosphorylation levels of JNK and ERK, not p38; however, it was attenuated by administration of an IGF­1R antagonist.

Glucagon-like peptide-1 analogue liraglutide ameliorates atherogenesis via inhibiting advanced glycation end product-induced receptor for advanced glycosylation end product expression in apolipoprotein-E deficient mice.

Glucagon-like peptide-1 (GLP-1) can protect arteriosclerotic lesions in apolipoprotein-E deficient (ApoE-/-) mice. Advanced glycation end products (AGEs)/receptor for advanced glycation end products (RAGE) interaction serves a key role in the development of diabetic vascular complications. The present study examined whether the GLP-1 analogue liraglutide can ameliorate atherogenesis via inhibiting AGEs-induced RAGE expression. Male ApoE-/- mice (age, 10 weeks) were divided into control, GLP-1, AGEs and AGEs+GLP-1 group. All mice were fed a high-fat diet. The AGEs and AGEs+GLP-1 groups were treated with intraperitoneal injection of AGEs (30 mg/kg/day). The GLP-1 and AGEs+GLP-1 groups were treated with subcutaneous injections of liraglutide (0.4 mg/kg/day). After 9 weeks, blood was drawn and the aortas were rapidly procured. The serum levels of AGEs, soluble RAGE (sRAGE), stromal cell-derived factor-1α (SDF-1α), total cholesterol and triacylglycerol were measured. Atherosclerotic plaque area was determined by Sudan IV staining. The mRNA and protein expression levels of RAGE were determined using reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. The results demonstrated that AGEs treatment increased serum AGEs levels, increased the expression of RAGE in the aorta, and aggravated atherosclerotic lesions compared with the control. Liraglutide treatment reduced serum AGEs levels, reduced the expression of RAGE in aorta, and relieved atherosclerotic lesions compared with the control. In conclusion, these data suggested that liraglutide serves an anti-atherosclerotic effect via inhibiting AGEs-induced RAGE expression in ApoE-/- mice. These findings provide novel evidence for the use of GLP-1-type agents for the treatment of diabetic vascular complications.

Microflora Disturbance during Progression of Glucose Intolerance and Effect of Sitagliptin: An Animal Study.

Background. Emerging evidences have shown a close interplay between obesity, diabetes, and intestinal flora disturbance. Dipeptidyl peptidase-4 inhibitor, exemplified by sitagliptin, is highly efficacious in treating type 2 diabetes (T2DM), yet little is known if sitagliptin exerts beneficial effects on microbiota associated with obesity and T2DM. We evaluated changes of gut microbiota following the induction of obesity and T2DM in a streptozotocin treated high fat/high carbohydrate fed (HF/HC-STZ) rat model and explored the effect of sitagliptin on gut microbiota for HF/HC-STZ rats. Methods. Sitagliptin was administered via oral gavage to diabetic rats. Fecal DNA extraction and 454 pyrosequencing based on analysis of 16S rRNA genes was utilized to determine the overall structure of microbiota in fecal DNA samples. Results. Results showed that, at the level of phylum, there was higher abundance of Firmicutes and Tenericutes and less abundance of Bacteroidetes in obese rats compared to their lean counterparts. At the level of genus, short-chain fatty acid- (SCFA-) producing bacteria, Blautia, Roseburia, and Clostridium, and probiotics Lactobacillus, Bifidobacterium, and so forth were identified significantly different from each other among conditions. Conclusion. Marked shifts of the gut microbiota structure were observed in the rats during development of glucose intolerance. Intestinal flora changed in the process of glucose intolerance, and treatment of sitagliptin moderately corrected the dysbiosis of microbiota in T2DM.

Structural modulation of the gut microbiota and the relationship with body weight: compared evaluation of liraglutide and saxagliptin treatment.

The mechanisms underlying the weight-loss effect of GLP-1 receptor agonists need further elucidation. The present study was performed to explore the effects of liraglutide and saxagliptin on the composition of the gut microbiota. Mice were randomly treated with saxagliptin or liraglutide for eight weeks. Their metabolic profiles were assessed, and 454 pyrosequencing of 16s rRNA of faeces was performed. Liraglutide induced a smaller body weight gain in mice. The pyrosequencing showed that liraglutide, but not saxagliptin, substantially changed the overall structure of the gut microbiota as well as the relative abundance of weight-relevant phylotypes. Subsequent ridge regression analyses indicated that, in addition to food intake (ß = -0.182, p = 0.043 in phylotypes inversely correlated with body weight) and blood glucose level (ß = -0.240, p = 0.039 in phylotypes positively correlated with body weight), the administration of liraglutide was another independent factor associated with the abundance of weight-relevant phylotypes (ß = 0.389, p = 6.24e-5 in inversely correlated ones; ß = -0.508, p = 2.25e-5 in positively correlated ones). These results evidenced that GLP-1 receptor agonist liraglutide could modulate the composition of the gut microbiota, leading to a more lean-related profile that was consistent with its weight-losing effect.

Effect of exercise on the expression of adiponectin mRNA and GLUT4 mRNA in type 2 diabetic rats.

To investigate the impact of exercise on the expression of adiponectin and GLUT4 mRNA in type 2 diabetic rats, type 2 diabetic rat model was made. The diabetic rats were treated with swimming training for 8 weeks. The expression of adiponectin mRNA in perirenal fat and GLUT4 mRNA in skeletal muscles were assessed by reverse transcription polymerase chain reaction (RT-PCR) and the levels of blood glucose, serum insulin, and blood lipid were measured. Our results showed that the expression of adiponectin mRNA and GLUT4 mRNA in diabetic model group was decreased by 45% (P < 0.01), 43% (P < 0.01) respectively. The gene expression of adiponectin and GLUT4 was increased significantly in swimming group (P < 0.05 and P < 0.01, respectively). Compared with the model group, fasting insulin, TG, TC and FFA were decreased significantly in the training group (P < 0.05 or P < 0.01) as compared with model group. It is concluded that exercise can promote the expression of adiponectin mRNA and GLUT4 mRNA in type 2 diabetic rats, which may be one of the mechanisms responsible for the amelioration of insulin resistance in the rats.

Astragalus polysaccharides affect insulin resistance by regulating the hepatic SIRT1-PGC-1α/PPARα-FGF21 signaling pathway in male Sprague Dawley rats undergoing catch-up growth.

The present study investigated the effects of Astragalus polysaccharides (APS) on insulin resistance by modulation of hepatic sirtuin 1 (SIRT1)­peroxisome proliferator­activated receptor (PPAR)­Î³ coactivator (PGC)­1α/PPARα­fibroblast growth factor (FGF)21, and glucose and lipid metabolism. Thirty male Sprague Dawley rats were divided into three groups: A normal control group, a catch­up growth group and an APS­treated (APS-G) group. The latter two groups underwent food restriction for 4 weeks, prior to being provided with a high fat diet, which was available ad libitum. The APS­G group was orally treated with APS for 8 weeks, whereas the other groups were administered saline. Body weight was measured and an oral glucose tolerance test (OGTT) was conducted after 8 weeks. The plasma glucose and insulin levels obtained from the OGTT were assayed, and hepatic morphology was observed by light and transmission electron microscopy. In addition, the mRNA expression levels of PGC­1α/PPARα, and the protein expression levels of SIRT1, FGF21 and nuclear factor­κB were quantified in the liver and serum. APS treatment suppressed abnormal glycolipid metabolism and insulin resistance following 8 weeks of catch­up growth by improving hepatic SIRT1­PPARα­FGF21 intracellular signaling and reducing chronic inflammation, and by partially attenuating hepatic steatosis. The suppressive effects of APS on liver acetylation and glycolipid metabolism­associated molecules contributed to the observed suppression of insulin resistance. However, the mechanism underlying the effects of APS on insulin resistance requires further research in order to be elucidated. Rapid and long­term treatment with APS may provide a novel, safe and effective therapeutic strategy for type 2 diabetes.

Angiographic evaluation of the effects of glucose metabolic status on progression of coronary artery lesions in patients with coronary artery disease.

BACKGROUND: The aim of the present study was to assess the effect of glucose metabolic status on the progression of coronary artery lesions in patients with coronary artery disease (CAD). METHODS: Two hundred and ninety-eight CAD patients who underwent coronary angiography were included in the study; follow-up angiography was performed after 9-15 months. The Gensini score, SYNTAX score, and the number of diseased vessels (at baseline and follow-up, as well as the change from baseline to follow-up) were used to determine the severity and progression of coronary artery lesions. The relationship between glucose metabolic status and progression of coronary artery lesions was investigated. Based on results of an oral glucose tolerance test, patients were divided into three groups: normal glucose tolerance (NGT); impaired glucose regulation(IGR); and type 2 diabetes mellitus (DM). RESULTS: Compared with the NGT group, changes (from baseline to follow-up) in the Gensini score, SYNTAX score, and the number of diseased vessels were significantly higher in the IGR and DM groups. There were no significant differences between the IGR and DM groups. Multivariate regression analysis suggested abnormal glucose metabolism was an independent risk factor for greater changes in the Gensini and SYNTAX scores, as well as for a greater number of diseased vessels. CONCLUSIONS: Greater progression of coronary artery lesions is seen in patients with abnormal glucose metabolism (DM and/or IGR), even when levels of HbA1c are on target.