Search

Background: Conflicting results have been reported on the efficacy of insulin degludec/insulin aspart (IDegAsp) compared to basal insulin in type 2 diabetes. We investigated the effects of changing basal insulin to IDegAsp on glycemic control and sought to identify factors related to those effects., Methods: In this retrospective study of patients from three referral hospitals, patients with type 2 diabetes using basal insulin with hemoglobin A1c (HbA1c) levels less than 11.0% were enrolled. Basal insulin was replaced with IDegAsp, and data were analyzed from 3 months before to 3 months after the replacement., Results: Eighty patients were recruited (52.5% male; mean age, 67.0±9.8 years; mean duration of diabetes, 18.9±8.5 years; mean HbA1c, 8.7%±1.0%). HbA1c levels increased during 3 months of basal insulin use, but significantly decreased after changing to IDegAsp (8.28%±1.10%, P =0.0001). The reduction was significant at 6 months in 35 patients whose longer-term data were available. Patients with a measured fasting plasma glucose (m-FPG) lower than their predicted FPG (p-FPG) by regression from HbA1c showed a significant HbA1c reduction caused by the change to IDegAsp, even without a significantly increased insulin dose. However, patients whose m-FPG was higher than their p-FPG did not experience a significant HbA1c reduction, despite a significantly increased insulin dose. Furthermore, the HbA1c reduction caused by IDegAsp was significant in patients with low fasting C-peptide levels and high insulin doses., Conclusion: We observed a significant glucose-lowering effect by replacing basal insulin with IDegAsp, especially in patients with a lower m-FPG than p-FPG., Competing Interests: No potential conflict of interest relevant to this article was reported., (Copyright © 2019 Korean Endocrine Society.)

Background: We have reported that partial PERK attenuation using PERK inhibitors (PI) enhanced glucose-stimulated insulin secretion (GSIS) from pancreatic islets and mice through induction of ER chaperone BIP. Therefore, we investigated if PI would have the same effects in a diabetic condition as well., Methods: GSK2606414 was treated to mouse islets under 20-mM glucose and 0.5-mM palmitate to examine GSIS. To generate a mouse model of type 2 diabetes mellitus (DM), male C57BL/6J mice were fed with high-fat diet and injected with streptozotocin. Several doses (6-16 mg/kg/day) of GSK2656157 and glimepiride were administrated to the mice for 8 weeks, and metabolic phenotypes were evaluated such as body weight, blood glucose levels, insulin secretion and sensitivity, and then changes in the pancreas were measured., Results: High-glucose and palmitate treatment significantly increased PERK phosphorylation in the isolated islets. Suppression of GSIS and glucose-stimulated Ca 2+ transit was also observed. PI at 40 nM which decreased PERK phosphorylation by 40% significantly recovered the GSIS and cytosolic calcium. In the mice where significant weight gain and prominent hyperglycemia were induced, PI at 10 mg/kg/day significantly enhanced GSIS and reduced blood glucose levels compared to the vehicle. The effects were similar to those by 10 mg/kg/day of glimepiride. Administration of PI did not induce changes in beta cell mass or pancreatic insulin contents, however, high dose PI decreased pancreatic weight., Conclusion: PI at low dose significantly enhanced GSIS in vitro and in vivo under metabolic stress and improved hyperglycemia in the mice mimicking type 2 DM, suggesting a potential as a new therapeutic approach for type 2 DM., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Type 2 diabetes is caused by both insulin resistance and relative insulin deficiency. To investigate age-related changes in glucose metabolism and development of type 2 diabetes, we compared glucose homeostasis in different groups of C57BL/6J mice ranging in age from 4 months to 20 months (4, 8, 12, 16 and 20 months). Interestingly, we observed that non-fasting glucose levels were not significantly changed, but glucose tolerance gradually increased by 20 months of age, whereas insulin sensitivity declined with age. We found that the size of islets and glucose-stimulated insulin secretion increased with aging. However, mRNA expression of pancreatic and duodenal homeobox 1 and granuphilin was decreased in islets of older mice compared with that of 4-month-old mice. Serum calcium (Ca2+) levels were significantly decreased at 12, 20 and 28 months of age compared with 4 months and calcium sensing receptor (CaSR) mRNA expression in the islets significantly increased with age. An extracellular calcium depletion agent upregulated CaSR mRNA expression and consequently enhanced insulin secretion in INS-1 cells and mouse islets. In conclusion, we suggest that decreased Ca2+ levels and increased CaSR expression might be involved in increased insulin secretion to compensate for insulin resistance in aged mice.

In this study, the effects of autologous islet transplantation (ITx) were compared to those of oral antidiabetic drugs (OAD) after distal pancreatectomy (NCT01922492). We enrolled nondiabetic patients who underwent distal pancreatectomy for benign tumors. In the ITx group, islets were isolated from the normal part of the resected pancreas and implanted via the portal vein. Patients who did not receive ITx were regularly monitored and were enrolled in the OAD group if diabetes mellitus developed. The OAD group was treated with metformin with or without vildagliptin. Metabolic parameters were monitored for 12 months postoperatively. Nine patients in the ITx group and 10 in the OAD group were included in the analysis. After 12 months, hemoglobin A1c significantly increased by 5% of the baseline in each group. Area under the curve for blood glucose (AUCglucose) of the 75-g oral glucose tolerance test increased similarly in the immediate postoperative period in both groups but significantly reduced only in the ITx group thereafter. Insulinogenic index (INSindex) significantly decreased from 25.6 ± 18.9 to 4.7 ± 3.7 in the OAD group, while no significant change was observed in the ITx group (from 15.0 ± 4.5 to 11.0 ± 8.2). In the multiple regression analysis, ITx was an independent factor for changes in AUCglucose and INSindex. In addition, changes in INSindex in the ITx group after postoperative 6 months were associated with the efficacy of islet isolation, amount of grafts, and peak serum HMGB1 and VEGF levels after ITx. ITx was superior to OAD in maintaining insulin secretory capacity and glucose tolerance after distal pancreatectomy.

Background: Periosteum-derived progenitor cells (PDPCs) isolated from the adult periosteum can differentiate into several specific cell types. In this study, we examined the characteristics of human PDPCs and insulin-producing cells (IPCs) differentiated from PDPCs and their ability to ameliorate hyperglycemia when transplanted into streptozotocin-induced nonobese diabetic-severe combined immunodeficiency diabetic mice., Methods: Periosteum-derived progenitor cells were isolated from patients, expanded in culture, and subjected to a three-step differentiation protocol to produce IPCs. The expression of immunogenic, pluripotent, and pancreatic markers was examined, and glucose-stimulated insulin release in vitro was also assessed. Insulin-producing cells that differentiated from PDPCs were transplanted under the kidney capsule of streptozotocin-induced diabetic mice, and glucose levels and glucose tolerance were measured., Results: We found that PDPCs expressed the mesenchymal stem cell markers CD73, CD90, and CD105 and the pluripotent markers, octamer-binding transcription factor 4 and Nanog, but not sex-determining region Y-box 2 or Rex1. Periosteum-derived progenitor cells expressed human leukocyte antigen-ABC but did not express human leukocyte antigen-DR or the costimulatory molecules CD80 and CD86. Differentiated IPCs expressed pancreatic hormones (insulin, glucagon, somatostatin, and glucose transporter 2), hormone processing, and secretion molecules (prohormone convertase-1 and convertase-2, Kir6.2), and pancreatic transcription factors (neurogenin 3, pancreatic and duodenal homeobox 1, sex-determining region Y-box 17). When IPCs were stimulated with glucose in vitro, insulin secretion was elevated. Transplantation of IPCs under the kidney capsules of diabetic mice improved hyperglycemia and glucose tolerance. Human insulin was detected in the serum and kidney sections of mice transplanted with IPCs differentiated from PDPCs., Conclusion: These results suggest that IPCs differentiated from PDPCs might be an alternative source of β cells for treating diabetes.

This study was undertaken to investigate the effect of a magnetic resonance imaging (MRI) contrast agent, superparamagnetic iron oxide nanoparticle (SPIO), on signal transduction by glucose and insulin in pancreatic β-cells. INS-1 cells were labeled in culture medium containing clinically approved SPIO for 24 h. Labeled and unlabeled cells were stimulated with glucose (25 mM) or insulin (0.1-1 µM) for 12 h. The phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2) and protein kinase B (AKT) and intracellular insulin protein levels were assessed by Western blotting. After labeling with increasing amounts of SPIO, cytotoxicity was not observed, yet the intracellular iron concentration increased in a dose-dependent manner. SPIO labeling (200 µg Fe ml(-1)) induced a significant increase in ERK1/2 and AKT phosphorylation (labeled vs unlabeled, p < 0.05), but significantly reduced the glucose-stimulated phosphorylation of ERK1/2 and AKT and insulin-stimulated phosphorylation of AKT (labeled vs unlabeled, p < 0.05). The level of intracellular insulin protein was found to be lower in labeled cells than unlabeled cells (labeled vs unlabeled, p < 0.05). This study demonstrates that SPIO labeling alters some fundamental functional variables, at least in INS-1 cells, through modulation of the glucose- or insulin-induced activation of ERK1/2 and AKT, which leads to insulin biosynthesis., (Copyright © 2012 John Wiley & Sons, Ltd.)

The exposure to acute or chronic endoplasmic reticulum (ER) stress has been known to induce dysfunction of islets, leading to apoptosis. The reduction of ER stress in islet isolation for transplantation is critical for islet protection. In this study, we investigated whether tauroursodeoxycholate (TUDCA) could inhibit ER stress induced by thapsigargin, and restore the decreased glucose stimulation index of islets. In pig islets, thapsigargin decreased the insulin secretion by high glucose stimulation in a time-dependent manner (1h, 1.35+/-0.16; 2h, 1.21+/-0.13; 4h, 1.17+/-0.16 vs. 0h, 1.81+/-0.15, n=4, p<0.05, respectively). However, the treatment of TUDCA restored the decreased insulin secretion index induced by thapsigargin (thapsigargin, 1.25+/-0.12 vs. thapsigargin+TUDCA, 2.13+/-0.19, n=5, p<0.05). Furthermore, the culture of isolated islets for 24h with TUDCA significantly reduced the rate of islet regression (37.4+/-5.8% vs. 14.5+/-6.4%, n=12, p<0.05). The treatment of TUDCA enhanced ATP contents in islets (27.2+/-3.2pmol/20IEQs vs. 21.7+/-2.8pmol/20IEQs, n=9, p<0.05). The insulin secretion index by high glucose stimulation is also increased by treatment of TUDCA (2.42+/-0.15 vs. 1.92+/-0.12, n=12, p<0.05). Taken together, we suggest that TUDCA could be a useful agent for islet protection in islet isolation for transplantation., (Copyright 2010 Elsevier Inc. All rights reserved.)

The ginsenoside Rg3 is known to have a protective effect against hyperglycemia, obesity and diabetes in vivo. In this study, we examined the effect of Rg3 on insulin signaling and glucose uptake in cultured L6 myotubes. Rg3 increased glucose uptake both in the basal and insulin-induced states of L6 myotubes. Consistent with the increase in glucose uptake, Rg3 stimulated the phosphorylation of IRS-1 and Akt. Interestingly, Rg3 dramatically increased IRS-1 protein levels, while the protein level of Akt was not affected. Rg3 regulated IRS-1 expression at the transcriptional level and also increased the level of GLUT4 mRNA. Treatment of ginsam, in which Rg3 is the major compound of ginsenosides, increased the IRS-1 protein levels in OLEFT rats. In addition, we found that this effect of Rg3 on insulin signaling was not mediated by the AMPK pathway. In conclusion, these results suggest that Rg3 improves insulin signaling and glucose uptake primarily by stimulating the expression of IRS-1 and GLUT4.

The purpose of this study was to evaluate the effects of autologous islet transplantation (ITx) on glucose homeostasis and insulin secretory function after partial pancreatectomy (Px). Fourteen nondiabetic patients who underwent distal Px and autologous ITx for benign pancreatic tumors were enrolled in the study (Px + ITx group). Fourteen normal glucose-tolerant controls and 6 Px without ITx controls were recruited, and all groups were followed over a 24-month period. They performed the 75-g oral glucose tolerance test and the 1-mg glucagon stimulation test. Hemoglobin A(1c) was measured, and indices of insulin secretion were calculated. In the Px + ITx group, insulin secretion increased after a nadir at 6 months. Glucose tolerance, which had been abruptly impaired immediately after Px, recovered until 6 months and stabilized thereafter. As a result, differences in glucose intolerance emerged between the subjects in the Px group and those in the Px + ITx group at 24 months after Px. Characteristic variables in the better insulin secretory subjects in the Px + ITx group included younger age, less extensive pancreas resection, and a greater number of total islets. In summary, delayed amelioration of glucose intolerance was induced by autologous ITx after partial Px, even with a small number of islets.

Background: Pancreatic beta cells are known to regenerate, especially when insulin requirements are increased. Islet transplantation (ITx) is one strategy for insulin replacement in patients with diabetes. ITx can provide not only insulin in a physiological manner but also can exert additional effects such as beta-cell regeneration. This study examined the effects of ITx on endogenous beta-cell mass in mice., Methods: Male Balb/c mice were 70% pancreatectomized and transplanted with syngeneic islets, then compared with pancreatectomized mice with or without insulin treatment. Blood glucose levels and weight were evaluated for 10 days, with remnant pancreas obtained for evaluation of beta-cell mass and turnover., Results: Hyperglycemia and weight loss were induced after pancreatectomy (Px). After ITx or insulin treatment, blood glucose levels recovered to normal, and body weight started to increase. At 10 days after Px, fasting serum insulin levels, beta-cell mass, and insulin content in the remnant pancreas were higher in the ITx group than they were in the Px group. Insulin treatment after Px also increased beta-cell mass, but did not increase pancreatic insulin content compared with those in the Px group. The enhanced beta-cell mass and insulin content in the remnant pancreas of the ITx group resulted from increased beta-cell proliferation/neogenesis and from prevention of beta-cell apoptosis., Conclusions: These findings suggest that ITx after partial Px in mice enhances endogenous beta-cell regeneration and survival, rendering beta-cell mass increased and glucose homeostasis improved.

Aims/Introduction: The benefits of once‐daily insulin degludec/aspart (IDegAsp) compared with basal insulin in type 2 diabetes patients have not been established. Materials and Methods: This was a retrospective observational study. From a basal insulin cohort from three referral hospitals, patients were enrolled who initiated once‐daily IDegAsp. A control group maintaining basal insulin was selected by propensity score matching. Glycated hemoglobin (HbA1c) changes over a period of 6 months and associated clinical factors were evaluated. Results: The IDegAsp group and the control group comprised of 87 patients, respectively. Baseline HbA1c was comparable between the two groups (8.7 ± 0.9 vs 8.6 ± 0.9%, mean and standard deviation). After 6 months with matched insulin doses, HbA1c in the IDegAsp group was lower than that in the control group (8.1 ± 1.0 vs 8.4 ± 1.1%, P = 0.029). Among baseline variables, fasting plasma glucose (FPG) and fasting C‐peptide in the IDegAsp were lower than that in the control (FPG 124.2 ± 38.4 vs 148.0 ± 50.6 mg/dL, P < 0.001). Considering that the lower FPG despite the comparable HbA1c could be related with the efficacy of IDegAsp, subgroup analysis was carried out according to a ratio of FPG‐to‐estimated average glucose, which is calculated from HbA1c. When compared with each control group, the superiority of IDegAsp in the reduction of HbA1c was significant only in the patients with a lower FPG‐to‐estimated average glucose ratio (0.49 ± 0.09), but not in those with a higher FPG‐to‐estimated average glucose ratio (0.79 ± 0.20). Conclusions: We observed that IDegAsp was more effective than basal insulin in patients with an FPG lower than predicted by HbA1c, which might be related with insulin deficiency and postprandial hyperglycemia in patients on basal insulin therapy. [ABSTRACT FROM AUTHOR]

Objective: This study evaluated the efficacy of a smartphone-based, patient-centered diabetes care system (mDiabetes) for type 2 diabetes that contains comprehensive modules for glucose monitoring, diet, physical activity, and a clinical decision support system.Research Design and Methods: We conducted a 24-week, multicenter, randomized controlled trial with adult patients with inadequately controlled type 2 diabetes. The patients were randomly assigned to the mDiabetes group or the paper logbook (pLogbook) group. The primary end point was the difference of the change in HbA1c from baseline between the two groups.Results: HbA1c reduction from baseline was greater in the mDiabetes group (-0.40 ± 0.09%, n = 90) than in the pLogbook group (-0.06 ± 0.10%, n = 82). The difference of adjusted mean changes was 0.35% (95% CI 0.14-0.55, P = 0.001). The proportion of patients whose HbA1c fell below 7.0% (53 mmol/mol) was 41.1% for the mDiabetes group and 20.7% for the pLogbook group (odds ratio [OR] 2.01, 95% CI 1.24-3.25, P = 0.003). The percentage of patients who attained HbA1c levels below 7.0% (53 mmol/mol) without hypoglycemia was 31.1% in the mDiabetes group and 17.1% in the pLogbook group (OR 1.82, 95% CI 1.03-3.21, P = 0.024). There was no difference in the event numbers of severe hyperglycemia and hypoglycemia between the two groups.Conclusions: The implementation of the mDiabetes for patients with inadequately controlled type 2 diabetes resulted in a significant reduction in HbA1c levels, with tolerable safety profiles. [ABSTRACT FROM AUTHOR]

Glucagon-like peptide 1 (GLP-1) can increase pancreatic β-cells, and α-cells could be a source for new β-cell generation. We investigated whether GLP-1 increases β-cells through α-cell transdifferentiation. New β-cells originating from non-β-cells were significantly increased in recombinant adenovirus expressing GLP-1 (rAd-GLP-1)-treated RIP-CreER;R26-YFP mice. Proliferating α-cells were increased in islets of rAd-GLP-1-treated mice and αTC1 clone 9 (αTC1-9) cells treated with exendin-4, a GLP-1 receptor agonist. Insulin+glucagon+ cells were significantly increased by rAd-GLP-1 or exendin-4 treatment in vivo and in vitro. Lineage tracing to label the glucagon-producing α-cells showed a higher proportion of regenerated β-cells from α-cells in rAd-GLP-1-treated Glucagon-rtTA;Tet-O-Cre;R26-YFP mice than rAd producing β-galactosidase-treated mice. In addition, exendin-4 increased the expression and secretion of fibroblast growth factor 21 (FGF21) in αTC1-9 cells and β-cell-ablated islets. FGF21 treatment of β-cell-ablated islets increased the expression of pancreatic and duodenal homeobox-1 and neurogenin-3 and significantly increased insulin+glucagon+ cells. Generation of insulin+glucagon+ cells by exendin-4 was significantly reduced in islets transfected with FGF21 small interfering RNA or islets of FGF21 knockout mice. Generation of insulin+ cells by rAd-GLP-1 treatment was significantly reduced in FGF21 knockout mice compared with wild-type mice. We suggest that GLP-1 has an important role in α-cell transdifferentiation to generate new β-cells, which might be mediated, in part, by FGF21 induction. [ABSTRACT FROM AUTHOR]