20/(fasting C-peptide × fasting plasma glucose) is a simple and effective index of insulin resistance in patients with type 2 diabetes mellitus: a preliminary report

Serum fatty acid-binding protein 4 (FABP4) concentration is associated with insulin resistance in peripheral tissues, A clinical study

Type 2 diabetes mellitus (T2DM) is caused by insulin resistance and β cell dysfunction. In recent studies reported that several markers associated with insulin sensitivity in skeletal muscle, Adiponectin and other parameters, such as fatty acid-binding protein (FABP4), have been reported to regulate insulin resistance, but it remains unclear which factor mostly affects insulin resistance in T2DM. In this cross-sectional study, we evaluated the relationships between several kinds of biomarkers and insulin resistance, and insulin secretion in T2DM and healthy controls. We recruited 30 participants (12 T2DM and 18 non-diabetic healthy controls). Participants underwent a meal tolerance test during which plasma glucose, insulin and serum C-peptide immunoreactivity were measured. We performed a hyperinsulinemic-euglycemic clamp and measured the glucose-disposal rate (GDR). The fasting serum levels of adiponectin, insulin-like growth factor-1, irisin, autotaxin, FABP4 and interleukin-6 were measured by ELISA. We found a strong negative correlation between FABP4 concentration and GDR in T2DM (r = -0.657, p = 0.020). FABP4 also was positively correlated with insulin secretion during the meal tolerance test in T2DM (IRI (120): r = 0.604, p = 0.038) and was positively related to the insulinogenic index in non-DM subjects (r = 0.536, p = 0.022). Autotaxin was also related to GDR. However, there was no relationship with insulin secretion. We found that serum FABP4 concentration were associated with insulin resistance and secretion in T2DM. This suggests that FABP4 may play an important role in glucose homeostasis.

Marked alteration of glycemic profile surrounding lanreotide administration in acromegaly: A case report

Whether somatostatin analogs for acromegaly improve or worsen a patient's glycemic profile is controversial. A risk of hypoglycemia should be presumed, especially when patients receive insulin therapy, as the package inserts caution. However, a detailed clinical course of such a case has never been reported in research articles. An 80‐year‐old Japanese female diabetes patient treated with insulin therapy was diagnosed with acromegaly, and the somatostatin analog, lanreotide, was given. On day 4 of lanreotide treatment, repeated hypoglycemia as a result of exogenous insulin arose and the patient required inpatient care. After lanreotide treatment, the total daily insulin dose could be reduced, but her fasting C‐peptide level decreased from 1.6 to 0.4 ng/mL, implying improved insulin resistance and impaired endogenous insulin secretion. In the present case, marked alteration surrounding lanreotide administration was observed; careful co‐administration with insulin therapy is required, as the package insert cautions.

Teneligliptin, a Chemotype Prolyl-Thiazolidine-Based Novel Dipeptidyl Peptidase-4 Inhibitor with Insulin Sensitizing Properties

BACKGROUND AND OBJECTIVES

Teneligliptin, a chemotype prolyl-thiazolidine-based novel dipeptidyl peptidase (DPP)-4 inhibitor, was preliminarily shown to reduce insulin resistance in patients with type 2 diabetes mellitus (T2DM). The objective of this study is to further investigate the insulin sensitising properties of teneligliptin in comparison to those of sitagliptin.

METHODS

Treatment-naïve subjects with T2DM were administered 20 mg/day teneligliptin monotherapy (n = 45). As a comparator, 25-50 mg/day sitagliptin monotherapy was performed in a non-randomized manner (n = 71). No other drugs were administered. At 3 months, levels of diabetic parameters were compared with those at baseline.

RESULTS

At 3 months, while similar reductions of glycated hemoglobin (HbA1c) levels were observed with these two drugs, indexes for insulin sensitivity [homeostasis model assessment (HOMA)-R and 20/(C-peptide × fasting blood glucose (FBG)) levels] ameliorated only with teneligliptin. Then, the subjects were divided into two groups representing distinct degrees of insulin resistance; high HOMA-R (≥4) and low HOMA-R (<2) groups. With teneligliptin, similar decreases of HbA1c levels were observed in high (9.85-7.66 %, p < 0.0005) and low (10.12-8.51 %, p < 0.01) HOMA-R groups. HOMA-R (-32.6 %, p < 0.05) and non-high density lipoprotein cholesterol (non-HDL-C, -6 %, p < 0.05) levels significantly decreased and 20/(C-peptide × FBG) levels significantly increased (53 %, p < 0.001) in high HOMA-R group. HOMA-B levels increased in both groups with significant inter-group differences (+101.7 % in low HOMA-R group vs. +55.4 % in high HOMA-R group). Group 2. With sitagliptin, similar decreases of HbA1c levels were observed from those of teneligliptin in either high or low HOMA-R group, but no changes of HOMA-R, non-HDL-C or 20/(C-peptide × FBG) levels were noted. Increases of HOMA-B levels with sitagliptin were comparable to those with teneligliptin in either high or low HOMA-R group.

CONCLUSIONS

These results indicate that: (i) teneligliptin ameliorates insulin sensitivity and non-HDL-C levels in subjects with high degrees of insulin resistance. This is not the case with sitagliptin, though similar glycemic efficacies were observed. (ii) glycemic efficacy of teneligliptin may be determined by the balance of its capacity in modulating insulin resistance and beta-cell function depending on the degrees of baseline insulin resistance.

High Serum Advanced Glycation End Products Are Associated with Decreased Insulin Secretion in Patients with Type 2 Diabetes: A Brief Report

OBJECTIVE

Advanced glycation end products (AGEs) are important in the pathophysiology of type 2 diabetes mellitus (T2DM). They directly cause insulin secretory defects in animal and cell culture models and may promote insulin resistance in nondiabetic subjects. We have developed a highly sensitive liquid chromatography-tandem mass spectrometry method for measuring AGEs in human serum. Here, we use this method to investigate the relationship between AGEs and insulin secretion and resistance in patients with T2DM.

METHODS

Our study involved 15 participants with T2DM not on medication and 20 nondiabetic healthy participants. We measured the AGE carboxyethyllysine (CEL), carboxymethyllysine (CML), and methyl-glyoxal-hydro-imidazolone (MG-H1). Plasma glucose and insulin were measured in these participants during a meal tolerance test, and the glucose disposal rate was measured during a euglycemic-hyperinsulinemic clamp.

RESULTS

CML and CEL levels were significantly higher in T2DM than non-DM participants. CML showed a significant negative correlation with insulin secretion, HOMA-%B, and a significant positive correlation with the insulin sensitivity index in T2DM participants. There was no correlation between any of the AGEs measured and glucose disposal rate.

CONCLUSIONS

These results suggest that AGE might play a role in the development or prediction of insulin secretory defects in type 2 diabetes.

A novel hepatokine, HFREP1, plays a crucial role in the development of insulin resistance and type 2 diabetes

AIMS/HYPOTHESIS

Type 2 diabetes is highly correlated with nonalcoholic fatty liver disease (NAFLD). Hepatocyte-derived fibrinogen-related protein 1 (HFREP1) is a hepatokine that mediates NAFLD development; however, the role of HFREP1 in the development of insulin resistance and diabetes remains obscure.

METHODS

A total of 193 age- and sex-matched participants with normal glucose tolerance, impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and newly diagnosed diabetes (NDD) were recruited for a cross-sectional study. Plasma HFREP1 levels were measured and multivariate linear regression analysis was used to evaluate the relationship between HFREP1, IFG, IGT and NDD. The causal relationship between HFREP1 and insulin resistance was then investigated in animal and cell models. Glucose and insulin tolerance tests, and euglycaemic-hyperinsulinaemic clamp, were used to evaluate insulin sensitivity in animals with Hfrep1 overexpression or knockdown in liver by lentiviral vectors. HepG2 cells were used to clarify the possible mechanism of HFREP1-induced insulin resistance.

RESULTS

Plasma HFREP1 concentrations were significantly increased in participants with IFG, IGT and NDD. HFREP1 concentrations were independently associated with fasting plasma glucose levels, insulin resistance, IFG, IGT and NDD. Injection of recombinant HFREP1 or Hfrep1 overexpression induced insulin resistance in mice, and HFREP1 disrupted insulin signalling to induce insulin resistance through an extracellular signal-regulated kinase (ERK)1/2-dependent pathway. Moreover, hepatic knockdown of HFREP1 improved insulin resistance in both mice fed a high-fat diet and ob/ob mice.

CONCLUSIONS/INTERPRETATION

These findings highlight the crucial role of HFREP1 in insulin resistance and diabetes, and provide a potential strategy and biomarker for developing therapeutic approaches to combat these diseases.

C-Peptide-Based Index Is More Related to Incident Type 2 Diabetes in Non-Diabetic Subjects than Insulin-Based Index

BACKGROUND

Diabetes can be efficiently prevented by life style modification and medical therapy. So, identification for high risk subjects for incident type 2 diabetes is important. The aim of this study is to identify the best β-cell function index to identify high risk subjects in non-diabetic Koreans.

METHODS

This is a retrospective longitudinal study. Total 140 non-diabetic subjects who underwent standard 2-hour 75 g oral glucose tolerance test from January 2007 to February 2007 at Kangbuk Samsung Hospital and followed up for more than 1 year were analyzed (mean follow-up, 54.9±16.4 months). The subjects were consist of subjects with normal glucose tolerance (n=44) and subjects with prediabetes (n=97) who were 20 years of age or older. Samples for insulin and C-peptide levels were obtained at 0 and 30 minutes at baseline.

RESULTS

Thirty subjects out of 140 subjects (21.4%) developed type 2 diabetes. When insulin-based index and C-peptide-based index are compared between progressor and non-progressor to diabetes, all C-peptide-based indices were statistically different between two groups, but only insulinogenic index and disposition index among insulin-based index were statistically different. C-peptide-based index had higher value of area under receiver operating characteristic curve (AROC) value than that of insulin-based index. "C-peptidogenic" index had highest AROC value among indices (AROC, 0.850; 95% confidence interval, 0.761 to 0.915). C-peptidogenic index had significantly higher AROC than insulinogenic index (0.850 vs. 0.731 respectively; P=0.014).

CONCLUSION

C-peptide-based index was more closely related to incident type 2 diabetes in non-diabetic subjects than insulin-based index.

Distinct glucose-lowering properties in good responders treated with sitagliptin and alogliptin

BACKGROUND AND OBJECTIVES

All dipeptidyl peptidase 4 (DPP-4) inhibitors display similar glycemic efficacies, although they differ greatly in their chemical structures and pharmacological properties. This may be due to the inclusions of non- or poor-responders in the analysis, thereby masking the real effects of these drugs. The aim of this study was to identify any differences in diabetic parameters only in good responders treated with sitagliptin and alogliptin.

METHODS

Treatment naïve subjects with type 2 diabetes mellitus were assigned to either sitagliptin 25-50 mg/day (n = 69) or alogliptin 12.5-25 mg/day monotherapy (n = 62) for 3 months. Only those who showed good response selected by a novel parameter called A1c index were further analysed (n = 24 for sitagliptin and n = 21 for alogliptin).

RESULTS

At baseline, FBG and BMI were significantly higher and CPR-index was significantly lower in alogliptin good responders. At 3 months, while similar reductions of HbA1c were observed in these two groups, decreases of fasting blood glucose (FBG) were significantly higher in alogliptin good responders. Homeostasis model assessment (HOMA)-R significantly decreased only in alogliptin good responders, while HOMA-B similarly and significantly increased in these two groups. BMI significantly increased only in sitagliptin good responders. Significant negative correlations were observed between A1c index and changes (Δ) of HOMA-B in both groups. By contrast, significant positive and negative correlations were observed between ΔFBG and ΔHOMA-R, and between ΔFBG and ΔHOMA-B, respectively, only in alogliptin good responders.

CONCLUSIONS

These results implicate that the effects on diabetic parameters and the glucose-lowering mechanisms of these two drugs might be different in those who have good response with these drugs. Accordingly, the choice of these drugs may be dependent on the characteristics of the patients.

Ipragliflozin: A novel sodium-glucose cotransporter 2 inhibitor developed in Japan

Sodium-glucose cotransporter 2 (SGLT2) inhibition induces glucosuria and decreases blood glucose levels in diabetic patients and lowers hypoglycemic risk. SGLT1 is expressed in the kidney and intestine; SGLT1 inhibition causes abdominal symptoms such as diarrhea and reduces incretin secretion. Therefore, SGLT2 selectivity is important. Ipragliflozin is highly selective for SGLT2. In type 2 diabetes mellitus (T2DM), urinary glucose excretion increased to 90 g/24 h after 28 d of treatment with ipragliflozin 300 mg/d. Twelve weeks of ipragliflozin 50 mg/d vs placebo reduced glycated hemoglobin and body weight by 0.65% and 0.66 kg, respectively, in Western T2DM patients, and by 1.3% and 1.89 kg, respectively, in Japanese patients. Ipragliflozin (highly selective SGLT2 inhibitor) improves glycemic control and reduces body weight and lowers hypoglycemic risk and abdominal symptoms. Ipragliflozin can be a novel anti-diabetic and anti-obesity agent.

Clinical usefulness of lipid ratios, visceral adiposity indicators, and the triglycerides and glucose index as risk markers of insulin resistance

Background

To directly compare traditional lipid ratios (total cholesterol [TC]/high density lipoprotein cholesterol [HDL-C], non-HDL-C/HDL-C, low density lipoprotein cholesterol [LDL-C]/HDL-C, and triglycerides [TG]/HDL-C), apolipoprotein B (apoB)/apolipoprotein A-I (apoA-I) ratio, visceral adiposity index (VAI), lipid accumulation product (LAP), and the product of TG and fasting glucose (TyG) for strength and independence as risk factors for insulin resistance (IR).

Methods

We conducted a cross-sectional analysis of 7629 Chinese adults using data from the China Health and Nutrition Survey 2009.

Results

For all lipid ratios (traditional lipid ratios and apoB/apoA-I), among both sexes, TG/HDL-C explained the most additional percentage of variation in HOMA-IR (2.9% in men, and 2.3% in women); for all variables of interest, the variability in HOMA-IR explained by VAI and TG/HDL-C were comparable; TyG had the most significant association with HOMA-IR, which explained 9.1% for men and 7.8% for women of the variability in HOMA-IR. Logistic regression analysis showed the similar patterns. Receiver operating characteristic (ROC) curve analysis showed that, among both sexes, TG/HDL-C was a better discriminator of IR than apoB/apoA-I; the area under the ROC curve (AUC) for VAI (0.695 in men and 0.682 in women) was greater than that for TG/HDL-C (AUC 0.665 in men and 0.664 in women); TyG presented the greatest value of AUC (0.709 in men and 0.711 in women).

Conclusion

The apoB/apoA-I performs no better than any of the traditional lipid ratios in correlating with IR. The TG/HDL-C, VAI and TyG are better markers for early identification of IR individuals.

Sitagliptin Improves the Impaired Acute Insulin Response during a Meal Tolerance Test in Japanese Patients with Type 2 Diabetes Mellitus: A Small-Scale Real-World Study

INTRODUCTION

Several studies have shown that dipeptidyl peptidase-4 (DPP-4) inhibitors improve insulin secretion during oral glucose tolerance tests. However, the effects of DPP-4 inhibitors on impaired acute insulin responses in the postprandial state in real-world settings are unknown. Therefore, we evaluated the effects of sitagliptin on the acute insulin responses in Japanese patients with type 2 diabetes mellitus (T2DM) using meal tolerance tests.

METHODS

Twenty-one patients with T2DM were given a test meal (460 kcal), and plasma glucose and insulin were measured at 0, 30, 60, 120, and 180 min after the meal. The insulinogenic index of all of these patients was below 43.2. The postprandial profiles were assessed at baseline and after 3 months of treatment with 50 mg/day sitagliptin after a meal (n = 11) or were untreated (control group; n = 10). This study was a prospective, open-label, non-blinded, non-randomized, clinical study.

RESULTS

Sitagliptin significantly decreased the plasma glucose levels at 60, 120, and 180 min, and significantly increased the plasma insulin levels at 0 and 30 min. There were no significant changes in glucose or insulin in the control group. The insulinogenic index increased significantly in the sitagliptin group compared with the control group (+16.7 vs. +0.1, P < 0.005). However, homeostasis model assessment of insulin resistance and the insulin sensitivity index were not significant different between the two groups.

CONCLUSION

Administration of sitagliptin at 50 mg/day after a meal improved the impaired acute insulin response and suppressed postprandial hyperglycemia. Whereas the study is rather small and the design is suboptimal as it is not randomized and not blinded, these results suggest that sitagliptin is effective in Japanese patients with T2DM, many of whom display impaired acute insulin responses after a meal.

Bezafibrate improves insulin resistance evaluated using the glucose clamp technique in patients with type 2 diabetes mellitus: a small-scale clinical study

BACKGROUND

Bezafibrate is mainly used to treat hypertriglyceridemia. Studies have reported that bezafibrate also improves type 2 diabetes mellitus, but the mechanism has not been fully elucidated. We performed euglycemic hyperinsulinemic clamps (glucose clamp) and meal tolerance tests (MTT) to examine the effects of bezafibrate on insulin resistance in patients with type 2 diabetes mellitus.

METHODS

Twelve Japanese patients with type 2 diabetes mellitus and dyslipidemia (mean age: 59.5 years; fasting plasma glucose: 7.95 mmol/L; hemoglobin A1c [HbA1c]: 7.3%; body mass index: 26.5 kg/m(2)) underwent a glucose clamp and MTT before and after 12 weeks of treatment with 400 mg/day bezafibrate. The glucose infusion rate was measured during the glucose clamp. The patients took a test meal (460 kcal) in the MTT. Plasma glucose and immunoreactive insulin levels were measured at 0 (fasting), 30, 60, 120, and 180 min. Serum C-peptide immunoreactivity, serum lipids, and liver function markers were also measured during the MTT.

RESULTS

Bezafibrate significantly increased the mean glucose infusion rate from 5.78 ± 1.94 to 6.78 ± 2.52 mg/kg/min (p < 0.05). HbA1c improved from 7.30 ± 0.55% to 7.02 ± 0.52% (p < 0.05). In the MTT, fasting plasma glucose decreased from 7.95 ± 1.15 to 6.98 ± 1.07 mmol/L (p < 0.05). The area under the plasma glucose curve from 0 to 180 min decreased significantly from 29.48 ± 5.07 to 27.12 ± 3.98 mmol/h/L (p < 0.05), whereas immunoreactive insulin was unchanged. Furthermore, bezafibrate also significantly improved serum lipids, with decreases in triglyceride levels from 1.84 ± 0.88 to 1.14 ± 0.41 mmol/L (p < 0.05), low-density lipoprotein cholesterol levels from 3.56 ± 0.83 to 2.92 ± 0.55 mmol/L (p < 0.05), and remnant-like particle cholesterol levels decreased from 0.25 ± 0.16 to 0.14 ± 0.06 mmol/L (p < 0.05), and increases in high-density lipoprotein cholesterol levels from 1.50 ± 0.24 to 1.66 ± 0.29 mmol/L (p < 0.05).

CONCLUSIONS

Bezafibrate improved glucose intolerance and peripheral insulin resistance in these Japanese patients with type 2 diabetes mellitus and dyslipidemia. Therefore, bezafibrate could be used to treat insulin resistance in patients with type 2 diabetes mellitus and dyslipidemia.

TRIAL REGISTRATION

University Hospital Medical Information Network (UMIN) Clinical Trials Registry, UMIN000012462.

Low serum galectin-3 concentrations are associated with insulin resistance in patients with type 2 diabetes mellitus

BACKGROUND

Galectin-3 is a family of soluble beta-galactoside-binding lectins that play many important regulatory roles in inflammation. Galectin-3-deficient mice have been shown to exhibit excess adiposity, hyperglycemia, insulin resistance and systemic inflammation. We investigated the association between serum galectin-3 and insulin resistance in patients with type 2 diabetes using a glucose clamp method.

METHODS

This was a cross-sectional study. Twenty patients (mean fasting plasma glucose 7.6 mmol/L, HbA1c 7.2%, BMI 28.1 kg/m(2)) underwent a meal tolerance test and glucose clamp test. Participants were given a test meal and plasma glucose and insulin were measured at 0, 30, 60, 120 and 180 min. The glucose disposal rate was measured during hyperinsulinemic-euglycemic glucose clamps. Serum galectin-3 levels were measured using the enzyme-linked immunosorbent assay method.

RESULTS

The mean serum galectin-3 level was 5103 pg/ml. Galectin-3 levels correlated significantly with the glucose disposal rate (R = 0.71, P < 0.001), fasting insulin (R = -0.56, P < 0.01), homeostasis model assessment for insulin resistance (R = -0.52, P < 0.05), and the insulin sensitivity index (R = 0.62, P < 0.005). Galectin-3 levels also positively correlated with the serum adiponectin level (R = 0.61, P < 0.05), but not with the high-sensitive C-reactive protein and interleukin-6 and -10.

CONCLUSIONS

These results suggest that low levels of serum galectin-3 are associated with insulin resistance in patients with type 2 diabetes.

Efficacy of initial Basal-supported oral therapy with sitagliptin in untreated type 2 diabetes

INTRODUCTION

The present study assessed the efficacy of initial basal-supported oral therapy (BOT) with sitagliptin for achievement of glycemic control and subsequent switching from BOT to sitagliptin-based oral therapy.

METHODS

Nineteen recently diagnosed type 2 diabetic patients who had received no antidiabetic medication in the previous 2 years were sequentially examined for the 24-week study. Patients were initially treated with a combination of insulin glargine and sitagliptin. Sitagliptin was initiated and maintained at a dose of 50 mg/day, and insulin glargine was started at a dose of 4 U at bedtime and adjusted if needed.

RESULTS

During the 24-week treatment period, 12 patients (63%) achieved HbA1c levels <7% (mean BOT duration 13.7 ± 5.6 weeks) and switched from BOT to sitagliptin monotherapy or in combination with metformin (achievers). The remaining seven patients (37%) failed to achieve HbA1c levels <7% (non-achievers) and continued on BOT. Both FPG and HbA1c in achievers significantly dropped at 4, 8, 12 and 24 weeks from baseline, while those in non-achievers significantly decreased at 12 and 24 weeks from baseline, but failed to reach target glycemic control. There were statistically significant differences in FPG at 4, 8, 12 and 24 weeks and in HbA1c at 8, 12 and 24 weeks between achievers and non-achievers. Body weight and BMI in achievers were significantly reduced at 12 and 24 weeks, but those in non-achievers did not change significantly. Dosage of concomitant insulin during BOT was significantly lower in achievers compared to non-achievers. Non-achievers had a similar CPI, a measure of insulin secretion capacity, to achievers, but significantly showed an insulin resistance index (value of 20/[fasting CPR × FPG]), in comparison to achievers.

CONCLUSION

Initiating BOT with sitagliptin followed by sitagliptin-based oral therapy is a useful option in untreated and poorly controlled patients with type 2 diabetes.

The proinsulin/insulin (PI/I) ratio is reduced by postprandial targeting therapy in type 2 diabetes mellitus: a small-scale clinical study

Background

An elevated PI/I ratio is attributable to increased secretory demand on β-cells. However, the effect of postprandial targeting therapy on proinsulin level is unknown. We evaluated the metabolic effect of glinide and sulfonylurea (SU) using the meal tolerance test (MTT).

Methods

MTT was applied to previously untreated Type 2 Diabetes Mellitus (T2DM) subjects. Twenty-two participants were given a test meal (450 kcal). Plasma glucose and insulin were measured at 0 (fasting), 30, 60, 120, and 180 min. Serum proinsulin and C-peptide immunoreactivity (CPR) were measured at 0 and 120 min. Postprandial profile was assessed at baseline and following 3 months treatment with either mitiglinide or glimepiride.

Results

Plasma glucose level at 30, 60, 120, and 180 min was significantly improved by mitiglinide. Whereas, glimepiride showed a significant improve plasma glucose at 0, 180 min. Peak IRI shifted from 120 to 30 min by mitiglinide treatment. The pattern of insulin secretion was not changed by glimepiride treatment. Whereas mitiglinide did not affect the PI/I ratio, glimepiride tended to increase the PI/I ratio. Moreover, although mitiglinide did not affect PI/I ratio as a whole, marked reduction was noted in some patients treated by mitiglinide. PI/I ratio was reduced significantly in the responder group. The responder subgroup exhibited less insulin resistance and higher insulinogenic index at baseline than non-responders. Moreover, the triglyceride level of responders was significantly lower than that of non-responders.

Conclusions

Mitiglinide improved postprandial insulin secretion pattern and thereby suppressed postprandial glucose spike. In T2DM patients with low insulin resistance and low triglyceride, mitiglinide recovered impaired β-cell function from the viewpoint of the PI/I ratio.

Trial registration

UMIN-CTR: UMIN000010467