Anorexigenic effects of miglitol in concert with the alterations of gut hormone secretion and gastric emptying in healthy subjects

Insulin Resistance Is Better Estimated by Using Fasting Glucose, Lipid Profile, and Body Fat Percent Than by HOMA-IR in Japanese Patients with Type 2 Diabetes and Impaired Glucose Tolerance: An Exploratory Study

Aims: The aim of the present study is to estimate insulin resistance (IR) using clinically available parameters except for serum insulin or C-peptide concentration to overcome the limitation of homeostasis model assessment of IR (HOMA-IR), which has been widely used in clinical practice. Patients and Methods: Fifty-two admitted patients with type 2 diabetes or impaired glucose tolerance were enrolled, and steady state plasma glucose (SSPG) method and cookie meal tolerance test were performed together with fasting blood sampling and anthropometric measurements. Insulin sensitivity measured by SSPG was estimated as glucose clearance corrected by the excretion of glucose into urine (C-GC). Results: Log-transformed (C-GC) was negatively correlated with fasting plasma glucose (FPG), log (Fasting triglyceride: TG), log (Fasting TG/Fasting high-density lipoprotein cholesterol: HDLC), and their area under the curves (AUCs). Fasting and AUC-HDLC was positively and fasting free fatty acid (FFA) was negatively correlated with log (C-GC). Body fat (%) was negatively correlated with log (C-GC). Multiple regression analysis on log (C-GC) as an outcome variable revealed that FPG, log (AUC-TG/AUC-HDLC), body fat (%), and fasting FFA were selected as significant predictive variables and contributed to log (C-GC) by 60% (adjusted R2). Replacing log (AUC-TG/AUC-HDLC) with its fasting value, log (Fasting TG/Fasting HDLC), this model still showed a strong contribution to log (C-GC) by 57% (adjusted R2). These contributions were stronger than those in log (HOMA-IR) (52.5%), log (Fasting C-peptide) (45.7%) to log (C-GC). Conclusions: It is plausible that our estimation for IR without the inclusion of plasma insulin concentration can be applied in Japanese patients whose HOMA-IR is not appropriately available. The model using fasting values is less complicated and could be the best way for the estimation of IR.

Callyspongia spp.: Secondary Metabolites, Pharmacological Activities, and Mechanisms

One of the most widespread biotas in the sea is the sponge. Callyspongia is a sponge genus found in the seas, making it easily available. In this review, the pharmacological activity and mechanism of action of the secondary metabolites of Callyspongia spp. are addressed, which may lead to the development of new drugs and targeted therapeutic approaches. Several scientific databases, such as Google Scholar, PubMed, ResearchGate, Science Direct, Springer Link, and Wiley Online Library, were mined to obtain relevant information. In the 41 articles reviewed, Callyspongia spp. was reported to possess pharmacological activities such as cytotoxicity against cancer cell lines (36%), antifungal (10%), anti-inflammatory (10%), immunomodulatory (10%), antidiabetic and antiobesity (6%), antimicrobial (8%), antioxidant (4%), antineurodegenerative (4%), antihypercholesterolemic (2%), antihypertensive (2%), antiparasitic (2%), antiallergic (2%), antiviral (2%), antiosteoporotic (2%), and antituberculosis (2%) activities. Of these, the antioxidant, antituberculosis, and anti-inflammatory activities of Callyspongia extract were weaker compared with that of the control drugs; however, other activities, particularly cytotoxicity, show promise, and the compounds responsible may be developed into new drugs.

Receptor-Mediated Bioassay Reflects Dynamic Change of Glucose-Dependent Insulinotropic Polypeptide by Dipeptidyl Peptidase 4 Inhibitor Treatment in Subjects With Type 2 Diabetes

Objective: We recently observed a greater increase in plasma levels of bioactive glucose-dependent insulinotropic polypeptide (GIP) than glucagon-like peptide 1 (GLP-1) using the receptor-mediated bioassays in the subjects with normal glycemic tolerance (NGT) treated with dipeptidyl peptidase 4 (DPP-4) inhibitors, which may be unappreciated using conventional enzyme-linked immunosorbent assays (ELISAs) during oral glucose tolerance test. Thus, we determined incretin levels in addition to glucagon level using the bioassays in type 2 diabetes mellitus (T2DM) subjects with or without treatment of DPP-4 inhibitor, to evaluate whether these assays can accurately measure bioactivity of these peptides. Methods: We performed single meal tolerance test (MTT) by using a cookie meal (carbohydrate 75.0 g, protein 8.0 g, fat 28.5 g) in the subjects with NGT (n = 9), the subjects with T2DM treated without DPP-4 inhibitor (n = 7) and the subjects with T2DM treated with DPP-4 inhibitor (n = 10). All subjects fasted for 10-12 h before the MTT, and blood samples were collected at 0, 30, 60, and 120 min. We used the cell lines stably cotransfected with human-form GIP, GLP-1 or glucagon receptor, and a cyclic adenosine monophosphate-inducible luciferase expression construct for the bioassays. We measured active GIP, active GLP-1, and glucagon by the bioassays. To evaluate the efficacy of bioassay, we measured identical samples via ELISA kits. Results: During the single MTT study, postprandial active GIP _bioassay levels of T2DM with DPP-4 inhibitor treatment were drastically higher than those of NGT and T2DM without DPP-4 inhibitor, although the DPP-4 inhibitor-treated group showed moderate increase of active GIP_ELISA and active GLP-1 _bioassay , while active GLP-1 _bioassay levels of T2DM subjects without DPP-4 inhibitor were comparable to those of NGT subjects. During the serial MTT, administration of DPP-4 inhibitor significantly increased active GIP _bioassay levels, but not active GLP-1 _bioassay . Conclusions: In comparison to conventional ELISA, receptor-mediated bioassay reflects dynamic change of GIP polypeptide by DPP-4 inhibitor treatment in subjects with type 2 diabetes.

Usefulness of antidiabetic alpha-glucosidase inhibitors: a review on the timing of administration and effects on gut hormones

Elevation of postprandial plasma glucose is correlated with an increase in cardiovascular events, and alpha-glucosidase inhibitors (αGIs) are effective at reducing postprandial glucose levels. In Japan, the αGIs acarbose, voglibose, and miglitol have been available since 1993, 1994, and 2006, respectively. Dipeptidyl peptidase-4 (DPP-4) inhibitors are also effective at reducing postprandial glucose levels, and they have been available in Japan since 2009. A combination therapy of αGI, miglitol, and the DPP-4 inhibitor, sitagliptin, is more effective at decreasing postprandial glucose levels than monotherapy with either miglitol or sitagliptin. Moreover, the combination therapy of miglitol and sitagliptin is more effective at increasing postprandial active glucagon-like peptide-1 (GLP-1) levels than monotherapy. Peptide YY (PYY) has appetite-suppressing and gastric-emptying effects similar to GLP-1. In healthy individuals, miglitol increases the postprandial total PYY; however, combination therapy of miglitol and vildagliptin does not change postprandial total PYY levels. αGIs are typically prescribed to be taken just before a meal, which can result in decreased drug adherence. Different patterns of αGI intake were examined, and the results showed that miglitol or acarbose administration after a meal is effective. The effects of taking miglitol dissolved in water during a meal appeared to be similar to that of taking miglitol as a tablet just before a meal. The long-term effects of taking miglitol dissolved in water should be evaluated in future studies. αGIs may be effective even when they are not taken before a meal, and a more flexible administration may improve drug adherence.

Efficacy and safety of combination therapy with an α-glucosidase inhibitor and a dipeptidyl peptidase-4 inhibitor in patients with type 2 diabetes mellitus: A systematic review with meta-analysis

AIMS/INTRODUCTION

The combination of dipeptidyl peptidase-4 (DPP4) inhibitors and α-glucosidase inhibitors (AGIs) might provide an additive or synergistic glucose-lowering effect, as they have a complementary mode of action. In the present study, we examined the efficacy and safety of the addition of a DPP4 inhibitor to patients with type 2 diabetes inadequately controlled with an AGI.

MATERIALS AND METHODS

We carried out an electronic search of MEDLINE, EMBASE, the Cochrane Library and Clinicaltrials.gov through October 2016. Randomized controlled trials written in English that compared DPP4 inhibitors plus AGI (DPP4i/AGI) and placebo plus AGI (PCB/AGI) in patients with type 2 diabetes were selected. Data on the study characteristics, efficacy and safety outcomes were extracted, and the risk of potential biases was assessed. The efficacy and safety of DPP4i/AGI and PCB/AGI were compared.

RESULTS

Of 756 potentially relevant published articles and 40 registered trials, five studies including 845 patients randomized to DPP4i/AGI and 832 patients randomized to PCB/AGI were included for meta-analysis. Compared with PCB/AGI, DPP4i/AGI showed a greater reduction in glycated hemoglobin (weighted mean difference -1.2%, 95% confidence interval -1.6 to -0.8), fasting plasma glucose and 2-h postprandial plasma glucose levels, with no increase in bodyweight. The risks of hypoglycemia and gastrointestinal adverse events were similar between DPP4i/AGI and PCB/AGI.

CONCLUSIONS

The addition of a DPP4 inhibitor to patients with type 2 diabetes inadequately controlled with an AGI achieved better glycemic control without further increasing the risk of weight gain and hypoglycemia.

Appetite and Gut Hormones Response to a Putative α-Glucosidase Inhibitor, Salacia Chinensis, in Overweight/Obese Adults: A Double Blind Randomized Controlled Trial

Animal studies indicate Salacia reduces body weight, possibly due to its α-glucosidase inhibitor (α-GI) properties, but this has not been examined previously. In this study, a randomized, placebo-controlled, three-way cross-over design was used to evaluate whether Salacia Chinensis (SC) reduces appetite in healthy overweight/obese individuals (body mass index 28.8 ±3.6 kg/m²; 32 ± 12 years). Forty-eight participants were fasted overnight and consumed a dose of SC (300 or 500 mg) or placebo with a fixed breakfast meal at each visit. Appetite sensations, glycemic indices and gastrointestinal peptides were measured. Results indicated that SC had no effect on postprandial appetite. However, in women, hunger was reduced by SC compared to placebo at multiple time points (300 mg; p < 0.05), but not in men. Area under the curve (AUC) for serum glucose, insulin and amylin was attenuated with SC compared to placebo (p < 0.05). Glucagon like peptide-1 had two peaks after the meal, but the AUC did not differ between groups. The AUC of peak areas for peptide YY and ghrelin were greater for SC than placebo (p < 0.05). These findings indicate that Salacia decreases glycemic indices supporting its role as an α-GI, and affects certain gastrointestinal peptides suggesting it may be an appetite modulator.

Review: Miglitol has potential as a therapeutic drug against obesity

The number of obese patients has increased annually worldwide. Therefore, there is a strong need to develop a new effective and safe anti-obesity drug. Miglitol is an alpha-glucosidase inhibitor (αGI) that is commonly used as an anti-diabetic drug, and there is growing evidence that it also has anti-obesity effects. Miglitol has been shown to reduce body weight and ameliorate insulin resistance in both clinical trials with adult patients and in rodent models of obesity. Although the specific mechanism of action of this effect remains unclear, some mechanisms have been suggested through experimental results. Miglitol has been shown to inhibit adipogenesis of white adipocytes in vitro, activate brown adipose tissue (BAT) in mice, influence bile acid metabolism in mice, and regulate the secretion of incretin hormones in humans. Among these results, we consider that BAT activation is likely the definitive mediator of miglitol's anti-obesity effect. A unique advantage of miglitol is that it is already used as an anti-diabetic drug with no severe side effects, whereas many of the anti-obesity drugs developed to date have been withdrawn because of their severe side effects. Miglitol is currently used clinically in a limited number of countries. In this review, we provide an overview of the state of research on miglitol for obesity treatment, emphasizing that it warrants more detailed attention. Overall, we demonstrate that miglitol shows good potential as a therapeutic for the treatment of obesity. Thus, we believe that further investigations of how it exerts its anti-obesity effect will likely contribute to the development of a new class of safe and effective drugs against obesity.

Postprandial effects of a polyphenolic grape extract (PGE) supplement on appetite and food intake: a randomised dose-comparison trial

Background

There is recent evidence that glucose delivered to the distal small intestine (SI) may stimulate the ileal brake and inhibit appetite. High polyphenolic grape extract (PGE) has been shown to inhibit α-amylase and α-glucosidase activity, two key enzymes required for starch digestion, in vitro. It is hypothesised to slow digestion and absorption of starch in the proximal SI such that glucose may be delivered distally into the ileum and suppress appetite. This study investigated the safety and efficacy of a PGE supplement, delivered within a capsule and consumed with a high-starch breakfast, on appetite ratings and ad libitum energy intake (EI) at a subsequent lunch meal.

Methods

Twenty healthy, non-obese (BMI 18–28 kg/m²) male volunteers participated in a randomised, double blind, placebo controlled, three arm, cross-over study. Participants were administered (i) low dose PGE₅₀₀ (500 mg), (ii) high dose PGE₁₅₀₀ (1500 mg), and (iii) matched placebo with a 2MJ high-starch breakfast (white bread); followed 3 h later by a single item buffet-style lunch meal (pasta and meat sauce). Outcome variables were feelings of hunger, fullness, prospective thoughts of food (TOF) and satisfaction assessed using visual analogue scales (VAS); and ad lib energy and macronutrient intake at the lunch meal.

Results

There was no detectable effect of PGE₅₀₀ or PGE₁₅₀₀ compared with placebo (all, time*supplement interaction, P > 0.05) on VAS-assessed hunger, fullness, TOF or satisfaction. There was also no evidence that PGE significantly altered ad lib energy or macronutrient intake at the lunch meal relative to placebo (P > 0.05). EI following PGE₅₀₀ was +164 kJ higher than placebo (+5.3 %, P > 0.05); and EI following PGE₁₅₀₀was −51 kJ lower than placebo (−1.7 %, P > 0.05).

Conclusions

Whilst well tolerated, there was no evidence that encapsulated low dose PGE₅₀₀ or high dose PGE₁₅₀₀ consumed with a high starch breakfast meal altered postprandial hunger, fullness, TOF or satisfaction relative to a matched placebo. Nor was there evidence that either dose altered ad lib energy or macronutrient intake at an outcome meal.

Trial registration

ACTRN12614000041651

Effects of Miglitol, Acarbose, and Sitagliptin on Plasma Insulin and Gut Peptides in Type 2 Diabetes Mellitus: A Crossover Study

INTRODUCTION

Both dipeptidyl peptidase-4 inhibitors and α-glucosidase inhibitors (α-GI) have been reported to change the incretin and insulin secretion. To examine the effects of acarbose, miglitol, and sitagliptin on glucose metabolism and secretion of gut peptides, we conducted a crossover study in patients with type 2 diabetes mellitus (T2DM).

METHODS

Eleven Japanese patients with T2DM underwent four meal tolerance tests with single administration of acarbose, miglitol, sitagliptin, or nothing. Fasting and postprandial plasma levels of glucose, insulin, glucagon, active glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), ghrelin, and des-acyl ghrelin were measured.

RESULTS

Early-phase insulin secretion was reduced following acarbose and miglitol, and the areas under the curve (AUC) of insulin at 180 min following acarbose and miglitol were significantly lower than sitagliptin. AUC of plasma glucose at 180 min after acarbose, miglitol, and sitagliptin tended to be lower than in controls, and plasma glucose levels at 30-60 min following miglitol were significantly lower than in controls. Plasma glucagon, ghrelin, and des-acyl ghrelin levels did not differ among the four conditions. Postprandial plasma active GLP-1 levels and AUC of GLP-1 increased significantly in both the sitagliptin and miglitol groups compared to control. Postprandial plasma total GIP levels increased following sitagliptin but decreased after acarbose and miglitol. Changes in incretin levels tended to be greater with miglitol than acarbose.

CONCLUSION

These results showed that sitagliptin and α-GIs, miglitol more so than acarbose, improved hyperglycemia in patients with T2DM after single administration, and had different effects on insulin and incretin secretion.

TRIAL REGISTRATION

UMIN-CTR number, UMIN000009981.

Greater dose-ranging effects on A1C levels than on glucosuria with LX4211, a dual inhibitor of SGLT1 and SGLT2, in patients with type 2 diabetes on metformin monotherapy

OBJECTIVE

To assess the dose-ranging efficacy and safety of LX4211, a dual inhibitor of sodium-glucose cotransporter (SGLT) 1 and SGLT2, in type 2 diabetes.

RESEARCH DESIGN AND METHODS

Type 2 diabetic patients inadequately controlled on metformin were randomly assigned to 75 mg once daily, 200 mg once daily, 200 mg twice daily, or 400 mg once daily of LX4211 or placebo. Primary end point was A1C change from baseline to week 12. Secondary end points included changes in blood pressure (BP) and body weight.

RESULTS

Baseline characteristics in 299 patients randomly assigned to LX4211 or placebo in this 12-week dose-ranging study were similar: mean age 55.9 years, A1C 8.1% (65 mmol/mol), BMI 33.1 kg/m(2), and BP 124/79 mmHg. LX4211 significantly reduced A1C to week 12 in a dose-dependent manner by 0.42% (4.6 mmol/mol), 0.52% (5.7 mmol/mol), 0.80% (8.7 mmol/mol), and 0.92% (10.0 mmol/mol), respectively (P < 0.001 each), compared with 0.09% (1.0 mmol/mol) for placebo. Greater A1C reductions were produced by 400 mg once a day than 200 mg once a day LX4211 without higher urinary glucose excretion, suggesting a contribution of SGLT1 inhibition. Significant reductions were seen in body weight (-1.85 kg; P < 0.001) and systolic BP (-5.7 mmHg; P < 0.001), but diastolic BP was unchanged (-1.6; P = 0.164). Adverse events with LX4211 were mild to moderate and similar to placebo, including urinary tract infections and gastrointestinal-related events; genital infections were limited to LX4211 groups (0-5.0%). No hypoglycemia occurred.

CONCLUSIONS

Dual inhibition of SGLT1/SGLT2 with LX4211 produced significant dose-ranging improvements in glucose control without dose-increasing glucosuria and was associated with reductions in weight and systolic BP in metformin-treated patients with type 2 diabetes.

Effects of miglitol, sitagliptin, and initial combination therapy with both on plasma incretin responses to a mixed meal and visceral fat in over-weight Japanese patients with type 2 diabetes. "the MASTER randomized, controlled trial"

AIM

To assess changes in circulating incretin levels and body fat compositions with initial combination therapy with α-glucosidase inhibitor and dipeptidyl peptidase-4 inhibitor in patients with type 2 diabetes (T2D).

METHODS

In this multicenter open-label 24-week trial, Japanese over-weight (BMI ≥ 25 kg/m(2)) patients with T2D not taking medication or taking metformin and/or sulfonylurea were randomly assigned to receive either 50mg of miglitol three times a day (M, n=14), 50mg of sitagliptin once a day (S, n=14), or a combination of both (M+S, n=13). Changes in plasma incretin levels during a meal tolerance test (MTT) and body fat composition with impedance method were evaluated.

RESULTS

During MTT, postprandial plasma glucose levels decreased more after M+S than after M or S, and postprandial serum insulin levels decreased significantly after M and M+S whereas they increased after S. After M, active gastric inhibitory polypeptide (aGIP) decreased significantly at 30 min despite a significant increase at 120 min. After S, aGIP levels increased significantly throughout the MTT. After M+S, aGIP increased significantly at 0 and 120 min despite of significant decrease at 30 min. M+S further enhanced postprandial active glucagon-like peptide-1 levels during MTT than S did. Total body fat mass decreased significantly after M and M+S. Visceral fat mass decreased significantly only after M+S. Serum adiponectin increased significantly only after M+S.

CONCLUSIONS

In over-weight patients with T2D, M+S may have a beneficial effect on adiposity with relation to these different effects on two incretins.

Effects of miglitol, vildagliptin, or their combination on serum insulin and peptide YY levels and plasma glucose, cholecystokinin, ghrelin, and obestatin levels

We previously reported that combination therapy with an α-glucosidase inhibitor (αGI) and a dipeptidyl peptidase-4 (DPP-4) inhibitor increased active glucagon-like peptide-1 (GLP-1) levels and decreased total glucose-dependent insulinotropic polypeptide (GIP) levels, compared with monotherapy, in non-diabetic men. However, the peptide YY (PYY), cholecystokinin (CCK), ghrelin, and obestatin levels in patients receiving a combination of αGIs and DPP-4 inhibitors have not been previously reported. We evaluated the effect of miglitol, vildagliptin, or their combination on these parameters. Miglitol and/or vildagliptin were administered according to four different intake schedules in eleven non-diabetic men (C: no drug, M: miglitol; V: vildagliptin, M+V: miglitol+vildagliptin). Blood samples were collected at 0, 30, 60, and 120 min after the start of breakfast. The plasma glucose, serum insulin, serum total PYY (PYY1-36 and PYY3-36), plasma CCK, plasma active ghrelin, and plasma obestatin levels were measured. The area under the curve (AUC) of the serum total PYY level in the M group was significantly greater than that in the C group, and the AUC of the serum total PYY level in the M+V group was significantly lower than that in the M group. The combination therapy did not change the AUC of the plasma CCK, plasma active ghrelin, plasma obestatin, and ghrelin/obestatin levels, compared with the control. The results of our study suggested that combination therapy with miglitol and vildagliptin had no effect on appetite regulation hormones, such as total PYY, CCK, active ghrelin, and obestatin, compared with the levels in the control group.