Effects of once-daily teneligliptin on 24-h blood glucose control and safety in Japanese patients with type 2 diabetes mellitus: a 4-week, randomized, double-blind, placebo-controlled trial

AIM

To assess blood glucose control over 24 h and the safety of teneligliptin 10 and 20 mg, a novel dipeptidyl peptidase-4 inhibitor, in Japanese patients with type 2 diabetes mellitus inadequately controlled with diet and exercise.

METHODS

Ninety-nine patients were administered teneligliptin 10 or 20 mg or placebo before breakfast for 4 weeks in a randomized, double-blind, placebo-controlled, parallel-group study.

RESULTS

Both teneligliptin-treated groups showed significantly smaller 2-h postprandial glucose (2-h PPG), 24-h mean glucose and fasting plasma glucose values than the placebo group. The differences between the teneligliptin 10 mg and placebo groups in changes in 2-h PPG after each meal were -50.7 ± 7.8, -34.8 ± 9.2 and -37.5 ± 7.5 mg/dl at breakfast, lunch and dinner, respectively [least-squares (LS) means ± standard error (s.e.), all, p < 0.001]. The corresponding LS means ± s.e. for teneligliptin 20 mg versus placebo were -38.1 ± 7.8, -28.6 ± 9.2 and -36.1 ± 7.5 mg/dl, respectively (p < 0.001, p < 0.01, p < 0.001, respectively). Both doses of teneligliptin increased postprandial plasma active glucagon-like peptide-1 concentrations compared with placebo. The incidence of adverse events and drug-related adverse events was similar among groups. There were no hypoglycaemic symptoms or serious adverse events.

CONCLUSIONS

Once-daily teneligliptin improved blood glucose levels over 24 h without hypoglycaemia.

Control of beta cell function and proliferation in mice stimulated by small-molecule glucokinase activator under various conditions

AIMS/HYPOTHESIS

We investigated changes in the expression of genes involved in beta cell function and proliferation in mouse islets stimulated with glucokinase activator (GKA) in order to elucidate the mechanisms by which GKA stimulates beta cell function and proliferation.

METHODS

Islets isolated from mice were used to investigate changes in the expression of genes related to beta cell function and proliferation stimulated by GKA. In addition, Irs2 knockout (Irs2 (-/-)) mice on a high-fat diet or a high-fat diet containing GKA were used to investigate the effects of GKA on beta cell proliferation in vivo.

RESULTS

In wild-type mice, Irs2 and Pdx1 expression was increased by GKA. In Irs2 (-/-) mice, GKA administration increased the glucose-stimulated secretion of insulin and Pdx1 expression, but not beta cell proliferation. It was particularly noteworthy that oxidative stress inhibited the upregulation of the Irs2 and Pdx1 genes induced by GKA. Moreover, whereas neither GKA alone nor exendin-4 alone upregulated the expression of Irs2 and Pdx1 in the islets of db/db mice, prior administration of exendin-4 to the mice caused GKA to increase the expression of these genes.

CONCLUSIONS/INTERPRETATION

GKA-stimulated IRS2 production affected beta cell proliferation but not beta cell function. Oxidative stress diminished the effects of GKA on the changes in expression of genes involved in beta cell function and proliferation. A combination of GKA and an incretin-related agent might therefore be effective in therapy.

Adiponectin, adiponectin receptors, and epigenetic regulation of adipogenesis

We studied the molecular mechanism of obesity-induced insulin resistance and adipogenesis. Plasma adiponectin and adiponectin receptor (AdipoR1) in muscle are down-regulated in obesity. Analysis of muscle-specific AdipoR1 knockout mice revealed the pivotal role of adiponectin/AdipoR1 in the regulation of mitochondrial biogenesis via AMPK- and SIRT1-mediated PGC-1α activation as well as Ca(2+)-dependent up-regulation of PGC-1α expression. Reduced adiponectin/AdipoR1 signals in muscle in obesity appear to cause PGC-1α inactivation as well as down-regulation and consequently impaired mitochondrial biogenesis and insulin resistance. In the epigenetic analysis of adipogenesis, we demonstrated that adipocyte-specific formaldehyde-assisted isolation of regulatory elements (FAIRE) peaks are associated with genes up-regulated by adipogenesis, whereas preadipocyte-specific FAIRE peaks are associated with genes down-regulated by adipogenesis. Computational motif analyses of adipocyte-specific FAIRE peaks confirmed PPARγ and CCAAT-enhancer binding proteins (C/EBPs) on the top list, consistent with their crucial roles in adipogenic transcription, and also revealed NFIA and NFIB to be important regulators of proper adipocyte differentiation.

The diabetogenic VPS13C/C2CD4A/C2CD4B rs7172432 variant impairs glucose-stimulated insulin response in 5,722 non-diabetic Danish individuals

AIMS/HYPOTHESIS

A genome-wide association study in the Japanese population reported two genome-wide significant loci associated with type 2 diabetes of which the VPS13C/C2CD4A/C2CD4B locus was replicated in Europeans. We looked for potential associations between the diabetogenic VPS13C/C2CD4A/C2CD4B rs7172432 variant and diabetes-related intermediary traits.

METHODS

We genotyped the rs7172432 variant in the population-based Inter99 cohort (n = 6,784) and analysed quantitative diabetes-related traits in 5,722 non-diabetic participants who all were examined by an OGTT.

RESULTS

The diabetes-associated A allele was associated with 0.60 cm higher waist circumference (p = 0.004), 0.037 mmol/l higher fasting plasma glucose (p = 4 × 10(-5)) and 0.11 mmol/l higher plasma glucose at 30 min during an OGTT (p = 4 × 10(-4)). In analyses adjusted for concomitant insulin sensitivity levels the diabetogenic allele was associated with a lower acute glucose-stimulated insulin response (GSIR) as estimated by 30 min serum insulin (β = -0.039, p = 2 × 10(-7)), insulinogenic index (β = -0.057, p = 1 × 10(-8)) and BIGTT-acute insulin release (β = -0.041, p = 9 × 10(-9)). As rs7172432 is situated in a region previously associated with glycaemic traits, we tested linkage disequilibrium (LD) with the reported regional lead single-nucleotide polymorphisms for fasting (rs11071657) and 2 h plasma glucose (rs17271305), and performed conditional analyses of rs7172432. Rs7172432 showed moderate LD with rs11071657 and rs17271305 (R (2) < 0.34) and we found strong association by almost unchanged effect sizes of rs7172432 with plasma glucose and estimates of GSIR in analyses conditional on rs11071657 and rs17271305.

CONCLUSIONS/INTERPRETATION

The diabetogenic VPS13C/C2CD4A/C2CD4B rs7172432 A allele associates with GSIR in non-diabetic individuals from the general population, suggesting an impaired beta cell function as an intermediary diabetes-related trait.

Living-donor liver transplantation at the University of Tokyo, 1996-2011: the impact of HLA matching and a positive crossmatch on long-term survival and tolerance

OBJECTIVE

We analyzed a single center's experience during 16 years of living-donor liver transplantation (LDLT). The impacts of HLA mismatches and positive crossmatches on long term outcomes and tolerance were evaluated.

METHODS

This study was of primary LDLTs of consecutive patients from January 1996 to December 2011; re-transplants were not included. Long-term survival was compared by primary disease, number of HLA mismatches, and crossmatches. Demographics and complications after transplantation between pediatric recipients who achieved clinical operational tolerance and those who did not were compared.

RESULTS

One-year liver graft survival rates for adult and pediatric cases were 90.4% and 91.9%, respectively; the 5-year rates were 83.1% and 89.2%, respectively; the 10-year rates were 79.7% and 89.2%, respectively; and 15-year rates were 65.9% and 83.8%, respectively. For the grafts that survived more than one year, the 10-year rates for adult and pediatric cases were 88.2% and 97.0%, respectively. The 10-year rates for adult LDLT in 0 mismatches, 1-2 mismatches, 3-4 mismatches, and 5-6 mismatches were 79.2%, 86.8%, 77.4%, and 69.4%, respectively. Although the survival rates were not significantly different, the survival rates were lowest in LDLT recipients with 5-6 HLA mismatches. Ten-year liver graft survival rates for adult LDLT with negative T-cell crossmatch, and positive T-cell crossmatch were 80.0% and 71.1%, respectively. The 1-year liver graft survival rates for adult LDLT with negative B-cell crossmatch, and positive B-cell crossmatch were 90.6% and 88.2%, respectively. None of the factors--age of recipients and donors, primary disease, donor gender, relationship of donors to recipients, positive crossmatches, or number of HLA mismatches--was significantly different between COT and non-COT recipients, except for recipient gender (p = 0.01); in COT cases, there were more female recipients (88.9%) than male (11.1%). Post-transplant complications--acute rejection rate in one year post-transplant, biliary complications rate, and vascular complication rate--were not significantly different between COT and non-COT recipients.

CONCLUSIONS

High long-term survival was achieved by both adult and pediatric recipients. Even higher survival can be achieved by improving early graft loss. Further studies are necessary to determine the impact of HLA mismatches and positive crossmatches on long-term outcomes and tolerance.

Abstract P6-08-02: Comparative Analysis between Primary and Secondary in Breast Tumors by Polymorphysim of Androgen Receptor Gene and Mitochondria D-Loop Somatic Mutation

Background: It has not been fully understood how we can differentiate a new primary breast cancer from a recurrent tumor, when second tumor arises in ipsilateral breast after the surgery for primary breast cancer. To address this research question, we estimate the usefulness of a method analyzing polymorphism of androgen receptor gene and mitochondrial D-loop somatic mutation.

Materials and methods: 1) Select patients: Among the 558 patients who received the breast conservative surgery in Tokai University Hospital (1991∼2004), 9 ipsilateral breast tumors and 11 contralateral breast tumors were submitted for the analysis. 2) Formalin-fixed paraffin-embedded (FFPE) sections of non-neoplastic lymph node were examined whether polymorphism of AR gene present or not. 3) When polymorphism of AR gene in non-neoplastic lymphoid tissue were demonstrated, ipsilateral and contralateral breast cancers were further examined. 4) When AR gene in breast cancers on same allele in primary and secondary tumors, FFPE sections were further analyzed by mutaion analysis of mitochondrial D-loop region.

Results: 1) Polymorphism of AR was demonstrated in 8/9 (88.9%) and 9/11 (81.8%) non-neoplastic lymph nodes obtained from the patients who had ipsilateral and contralateral breast tumor, respectively. 2) Only 2 of 8 ipsilateral breast cancers demonstrated AR polymorphism different from primary cancer. In contrast, 6 of 9 contralateral breast cancers had different polymorphism for AR from primary breast cancers. 3) Analysis of mitochondrial D-loop mutation showed that 8 seconary ipsilateral cancers had different mutation in 3/8 (37.5%), identical mutation in 3/8 (37.5%), and no mutation in 2/8 (25.0%).

Results of analysis for ipsilateral secondary breast cancers

Conclusion: Half of the ipsilateral in breast secondary tumors were estimated as new primary lesions by molecular estimation. Combination analyses of AR gene polymorphism and mitochondrial D-loop somatic mutation unable us to distinguish between true recurrent or new primary cancers.

Efficacy and safety of sitagliptin monotherapy compared with voglibose in Japanese patients with type 2 diabetes: a randomized, double-blind trial

OBJECTIVE

To compare the efficacy and safety of sitagliptin (a dipeptidyl peptidase-4 inhibitor) and voglibose (an alpha-glucosidase inhibitor) monotherapy in Japanese patients with type 2 diabetes who have inadequate glycaemic control (HbA1c > or =6.5% and <10.0%) on diet and exercise.

METHODS

In a multi-center, randomized, double-blind, parallel-group study, 319 patients were randomized (1:1) to 12-week treatment with sitagliptin 50 mg once daily or voglibose 0.2 mg thrice daily before meals. The primary analysis assessed whether sitagliptin was non-inferior to voglibose in lowering HbA1c.

RESULTS

After 12 weeks, sitagliptin was non-inferior to voglibose for HbA1c-lowering efficacy. Furthermore, sitagliptin was superior to voglibose, providing significantly greater reductions in HbA1c from baseline [least squares mean changes in HbA1c [95% confidence intervals (CI)] = -0.7% (-0.8 to -0.6) and -0.3% (-0.4 to -0.2), respectively; between-group difference = -0.4% (-0.5 to -0.3), p < 0.001]. Sitagliptin was also superior to voglibose on other key efficacy endpoints, including change from baseline in 2-h postmeal glucose (-2.8 mmol/l vs. -1.8 mmol/l, p < 0.001) and fasting plasma glucose (-1.1 mmol/l vs. -0.5 mmol/l, p < 0.001). After 12 weeks, the incidences of clinical adverse experiences (AEs), drug-related AEs and gastrointestinal AEs in the sitagliptin group (48.5, 10.4 and 18.4%, respectively) were significantly (p < 0.05) lower than those in the voglibose group (64.7, 26.3 and 34.6%, respectively). The incidences of hypoglycaemia, serious AEs and discontinuations due to AEs were low and similar in both groups.

CONCLUSIONS

In Japanese patients with type 2 diabetes, once-daily sitagliptin monotherapy showed greater efficacy and better tolerability than thrice-daily voglibose over 12 weeks.

Colestilan monotherapy significantly improves glycaemic control and LDL cholesterol levels in patients with type 2 diabetes: a randomized double-blind placebo-controlled study

AIM

To evaluate the plasma glucose-reducing activity and safety of colestilan, a bile acid sequestrant, in patients with type 2 diabetes.

METHODS

Patients with fasting plasma glucose (FPG) 7.2-11.1 mmol/l and HbA (1c)> or =7.0% were randomly allocated in double-blind manner to receive colestilan or placebo therapy for 12 weeks.

RESULTS

A total of 183 patients entered the double-blind treatment phase. At 12 weeks, colestilan significantly reduced HbA (1c) and FPG vs. placebo by 0.9% and 1.2 mmol/l respectively (both p < 0.001). A significant (p < 0.001) 22.5% reduction of LDL cholesterol was also observed in the 172 patients evaluated (colestilan group: n = 86; placebo group: n = 86). However, no significant reduction of fasting insulin was observed (p = 0.087). No incidence of hypoglycaemia was reported in this study.

CONCLUSION

Colestilan improved glycaemic control and reduced LDL cholesterol levels in patients with type 2 diabetes.

Simultaneous pancreas-kidney transplantation in the United States: an analysis of the UNOS registry

The rate of chronic pancreas graft loss in simultaneous pancreas kidney transplantation has remained almost unchanged despite induction therapy. Since 1987, seven major immunosuppressive induction agents-basiliximab, daclizumab, ALG, eATG, OKT 3, alembuzumab, rATG-have been used as immunosuppressive induction agents. Those agents improved short-term survival by preventing acute rejection, but improvement of short-term survival has not translated into improved long-term graft survival. As with most solid organ transplants, there is a need for means to control chronic rejection to improve long-term graft survival.

Effects of insulin glulisine as mono- or add-on therapy in patients with type 2 diabetes mellitus

AIM

To evaluate the safety and efficacy of insulin glulisine (glulisine) with and without oral antidiabetic drugs (OAD; sulphonylurea or sulphonylurea + biguanide) relative to that of OAD alone in Japanese and Korean patients with inadequately controlled type 2 diabetes mellitus (T2DM).

METHODS

In an open, randomized, parallel-group, comparative, controlled trial, 387 patients were randomized and treated with glulisine + OAD (n = 130), glulisine monotherapy (n = 127) or OAD only (n = 130) for 16 weeks. Glulisine was self-injected subcutaneously three times daily (0-15 minutes before meals) at a starting dose of >or=0.2 U/kg/day. Patients titrated the glulisine dose to achieve a 2-h postprandial plasma glucose (2h-PPG) level of 7.1-9.5 mmol/l (128-172 mg/dl) by administering at least one additional unit at each appropriate meal time if the 2h-PPG level was > 9.5 and < 11.1 mmol/l (> 172 and < 200 mg/dl) and by administering at least two additional units if the 2h-PPG level was >or= 11.1 mmol/l (>or= 200 mg/dl). Therapy with OAD was continued at the stable baseline regimen. The primary efficacy endpoint was change in haemoglobin A(1c) (HbA(1c)) from baseline to endpoint in the intention-to-treat population.

RESULTS

At baseline, therapy with OAD was a sulphonylurea only and a sulphonylurea + a biguanide in approximately 24 and 76% of patients respectively. Both glulisine groups had larger reductions in adjusted mean HbA(1c) than the OAD-only group (glulisine + OAD, -2.07%; glulisine monotherapy, -1.25%; OAD only, -0.61%). Superiority of glulisine + OAD and glulisine monotherapy vs. OAD only was shown by differences in adjusted mean HbA(1c) change from baseline values of -1.46% (p < 0.0001) and -0.64% (p < 0.0001) respectively. Both glulisine groups had better 2h-PPG control than the OAD-only group. Mean daily glulisine doses increased from baseline to endpoint (glulisine + OAD, 13.3-22.5 U; glulisine monotherapy, 14.2-38.0 U). The rate of all symptomatic hypoglycaemia events per patient-year in the entire treatment phase was 11.9 in the glulisine + OAD group, 8.8 in the glulisine monotherapy group and 1.7 in the OAD-only group. There was only one event of severe hypoglycaemia, which occurred in the glulisine + OAD group. Efficacy and safety were similar in Japanese and Korean subpopulations.

CONCLUSIONS

Both glulisine + OAD and glulisine monotherapy were well tolerated and effective for Japanese and Korean patients with T2DM mellitus inadequately controlled by OAD therapy alone.

Efficacy and safety of insulin glulisine in Japanese patients with type 1 diabetes mellitus

AIM

The rapid-acting insulin analogue insulin glulisine (glulisine) was compared with insulin lispro (lispro) for efficacy and safety in Japanese patients with type 1 diabetes mellitus (T1DM), using insulin glargine (glargine) as basal insulin.

METHODS

This was an open, randomized, parallel-group, comparative non-inferiority study. The primary efficacy measure was change in adjusted mean haemoglobin A1c (HbA1c) from baseline to endpoint. Safety and treatment satisfaction using the Diabetes Treatment Satisfaction Questionnaire (DTSQ) were also assessed. Patients were treated for 28 weeks with either glulisine or lispro administered 0-15 min before a meal. Doses were titrated to obtain 2-h postprandial plasma glucose (2h-PPG) of 7.11-9.55 mmol/l (128-172 mg/dl). All patients were concomitantly treated with glargine at bedtime, titrated to obtain a fasting (prebreakfast) plasma glucose level of 5.27-7.11 mmol/l (95-128 mg/dl).

RESULTS

Baseline mean HbA1c values were similar for the glulisine (n = 132) and lispro (n = 135) groups (7.44 and 7.50% respectively). From baseline to endpoint, adjusted mean HbA1c increased by 0.10% in the glulisine group and by 0.04% in the lispro group. Non-inferiority of glulisine compared with lispro was shown. There were no significant differences between glulisine and lispro in adjusted mean 2h-PPG [glulisine, 9.06 mmol/l (163 mg/dl) vs. lispro, 8.13 mmol/l (146 mg/dl); p = 0.065] and change in adjusted mean daily rapid-acting insulin dose (glulisine, 0.26 U vs. lispro, 0.26 U; p = 0.994) at study endpoint. There was a significant difference for change in adjusted mean daily basal insulin dose from baseline to study endpoint (glulisine, -0.54 U vs. lispro, 0.26 U; p = 0.013). The most common serious adverse events were hypoglycaemia-related events (hypoglycaemia, hypoglycaemic seizure and hypoglycaemic coma) with no difference observed between the two groups [glulisine, 6.8% (9/132) vs. lispro, 4.4% (6/135); p = 0.437]. No noteworthy differences were observed for change in insulin antibodies from baseline to endpoint. Assessment of treatment satisfaction score and perceived frequency of hyperglycaemia and hypoglycaemia by DTSQ showed no changes from baseline in either group.

CONCLUSIONS

Glulisine was as effective as lispro with respect to change in HbA1c and was well tolerated when used in combination with glargine in Japanese patients with T1DM.

Replication study for the association of new meta-analysis-derived risk loci with susceptibility to type 2 diabetes in 6,244 Japanese individuals

AIMS/HYPOTHESIS

Additional susceptibility loci for type 2 diabetes have been identified by a meta-analysis of genome-wide association studies (GWASs) in European populations. To examine further the roles of these new loci, we performed a replication study for the association of these single-nucleotide polymorphism (SNP) loci with the disease in three independent Japanese populations.

METHODS

We genotyped seven of the 11 SNPs that emerged in stage 2 of the meta-analysis for European GWASs (rs864745 in JAZF1, rs12779790 near CDC123/CAMK1D, rs7961581 near TSPAN8/LGR5, rs4607103 near ADAMTS9, rs10923931 in NOTCH2, rs1153188 near DCD and rs9472138 near VEGFA) for three independent Japanese populations (first set, 1,630 type 2 diabetes patients vs 1,064 controls; second set, 1,272 type 2 diabetes patients vs 856 controls; third set, 486 type 2 diabetes patients vs 936 controls) using a TaqMan assay. The association of the SNP loci in each population was analysed using a logistic regression analysis, adjusting for age, sex and BMI, and the data were evaluated by a meta-analysis.

RESULTS

A meta-analysis for the three case-control studies identified a nominal association of rs864745 in JAZF1 with type 2 diabetes (OR 1.148, 95% CI 1.034-1.275, p = 0.0098, corrected p = 0.069). The association of other loci did not reach statistically significant levels (nominal p > 0.05).

CONCLUSIONS/INTERPRETATION

From these results the contribution of these seven loci in conferring susceptibility to type 2 diabetes is considered minor in the Japanese population, if they are present.

The molecular basis and clinical characteristics of Maternally Inherited Diabetes and Deafness (MIDD), a recently recognized diabetic subtype

Diabetes mellitus comprises a number of diseases with hyperglycemia as hallmark. Currently, multiple genetic factors are being recognized which contribute to the development of diabetes or which may modulate its clinical expression. This review presents an overview of our current knowledge on a diabetic subtype which associates with a single mutation in mitochondrial DNA. Based on the triad of Maternal Inheritance, Diabetes and Deafness we propose the name Maternally Inherited Diabetes and Deafness (MIDD) for this syndrome. In Northwestern Europe MIDD affects approximately 1.3% of all diabetic individuals.

Adiponectin suppresses colorectal carcinogenesis under the high-fat diet condition

BACKGROUND AND AIMS

The effect of adiponectin on colorectal carcinogenesis has been proposed but not fully investigated. We investigated the effect of adiponectin deficiency on the development of colorectal cancer.

METHODS

We generated three types of gene-deficient mice (adiponectin-deficient, adiponectin receptor 1-deficient, and adiponectin receptor 2-deficient) and investigated chemical-induced colon polyp formation and cell proliferation in colon epithelium. Western blot analysis was performed to elucidate the mechanism which affected colorectal carcinogenesis by adiponectin deficiency.

RESULTS

The numbers of colon polyps were significantly increased in adiponectin-deficient mice compared with wild-type mice fed a high-fat diet. However, no difference was observed between wild-type and adiponectin-deficient mice fed a basal diet. A significant increase in cell proliferative activity was also observed in the colonic epithelium of the adiponectin-deficient mice when compared with wild-type mice fed a high-fat diet; however, no difference was observed between wild-type and adiponectin-deficient mice fed a basal diet. Similarly, an increase in epithelial cell proliferation was observed in adiponectin receptor 1-deficient mice, but not in adiponectin receptor 2-deficient mice. Western blot analysis revealed activation of mammalian target of rapamycin, p70 S6 kinase, S6 protein and inactivation of AMP-activated protein kinase in the colon epithelium of adiponectin-deficient mice fed with high-fat diet.

CONCLUSIONS

Adiponectin suppresses colonic epithelial proliferation via inhibition of the mammalian target of the rapamycin pathway under a high-fat diet, but not under a basal diet. These studies indicate a novel mechanism of suppression of colorectal carcinogenesis induced by a Western-style high-fat diet.

Crucial role of insulin receptor substrate-2 in compensatory beta-cell hyperplasia in response to high fat diet-induced insulin resistance

In type 2 diabetes, there is a defect in the regulation of functional beta-cell mass to overcome high-fat (HF) diet-induced insulin resistance. Many signals and pathways have been implicated in beta-cell function, proliferation and apoptosis. The co-ordinated regulation of functional beta-cell mass by insulin signalling and glucose metabolism under HF diet-induced insulin-resistant conditions is discussed in this article. Insulin receptor substrate (IRS)-2 is one of the two major substrates for the insulin signalling. Interestingly, IRS-2 is involved in the regulation of beta-cell proliferation, as has been demonstrated using knockout mice models. On the other hand, in an animal model for human type 2 diabetes with impaired insulin secretion because of insufficiency of glucose metabolism, decreased beta-cell proliferation was observed in mice with beta-cell-specific glucokinase haploinsufficiency (Gck(+/) (-)) fed a HF diet without upregulation of IRS-2 in beta-cells, which was reversed by overexpression of IRS-2 in beta-cells. As to the mechanism underlying the upregulation of IRS-2 in beta-cells, glucose metabolism plays an important role independently of insulin, and phosphorylation of cAMP response element-binding protein triggered by calcium-dependent signalling is the critical pathway. Downstream from insulin signalling via IRS-2 in beta-cells, a reduction in FoxO1 nuclear exclusion contributes to the insufficient proliferative response of beta-cells to insulin resistance. These findings suggest that IRS-2 is critical for beta-cell hyperplasia in response to HF diet-induced insulin resistance.