Acarbose: an alternative to metformin for first-line treatment in type 2 diabetes?

Kinetics and molecular modeling studies on the inhibition mechanism of GH13 α-glycosidases by small molecule ligands

Alpha-glucosidase inhibitors play an important role in Diabetes Mellitus (DM) treatment since they prevent postprandial hyperglycemia. The Glycoside Hydrolase family 13 (GH13) is the major family of enzymes acting on substrates containing α-glucoside linkages, such as maltose and amylose/amylopectin chains in starch. Previously, our group identified glycoconjugate 1H-1,2,3-triazoles (GCTs) inhibiting two GH13 α-glycosidases: yeast maltase (MAL12) and porcine pancreatic amylase (PPA). Here, we combined kinetic studies and computational methods on nine GCTs to characterize their inhibitory mechanism. They all behaved as reversible inhibitors, and kinetic models encompassed noncompetitive and various mechanisms of mixed-type inhibition for both enzymes. Most potent inhibitors displayed Ki values of 30 μM for MAL12 (GPESB16) and 37 μM for PPA (GPESB15). Molecular dynamics and docking simulations indicated that on MAL12, GPESB15 and GPESB16 bind in a cavity adjacent to the active site, while on the PPA, GPESB15 was predicted to bind at the entrance of the catalytic site. Notably, despite its putative location within the active site, the binding of GPESB15 does not obstruct the substrate's access to the cleavage site. Our study contributes to paving the way for developing novel therapeutic strategies for managing DM-2 through GH13 α-glycosidases inhibition.

Acarbose reduces Pseudomonas aeruginosa respiratory tract infection in type 2 diabetic mice

BACKGROUND

Type 2 diabetes mellitus (T2DM) is widely prevalent worldwide, and respiratory tract infections (RTIs) have become the primary cause of death for T2DM patients who develop concurrent infections. Among these, Pseudomonas aeruginosa infection has been found to exhibit a high mortality rate and poor prognosis and is frequently observed in bacterial infections that are concurrent with COVID-19. Studies have suggested that acarbose can be used to treat T2DM and reduce inflammation. Our objective was to explore the effect of acarbose on P. aeruginosa RTI in T2DM individuals and elucidate its underlying mechanism.

METHODS

High-fat diet (HFD) induction and P. aeruginosa inhalation were used to establish a RTI model in T2DM mice. The effect and mechanism of acarbose administered by gavage on P. aeruginosa RTI were investigated in T2DM and nondiabetic mice using survival curves, pathological examination, and transcriptomics.

RESULTS

We found that P. aeruginosa RTI was more severe in T2DM mice than in nondiabetic individuals, which could be attributed to the activation of the NF-κB and TREM-1 signaling pathways. When acarbose alleviated P. aeruginosa RTI in T2DM mice, both HIF-1α and NF-κB signaling pathways were inhibited. Furthermore, inhibition of the calcium ion signaling pathway and NF-κB signaling pathway contributed to the attenuation of P. aeruginosa RTI by acarbose in nondiabetic mice.

CONCLUSIONS

This study confirmed the attenuating effect of acarbose on P. aeruginosa RTIs in T2DM and nondiabetic mice and investigated its mechanism, providing novel support for its clinical application in related diseases.

Evaluation of Antidiabetic Effect of Combined Leaf and Seed Extracts of Moringa oleifera (Moringaceae) on Alloxan-Induced Diabetes in Mice: A Biochemical and Histological Study

Moringa oleifera (Moringaceae) is a medicinal plant rich in biologically active compounds. The aim of the present study was to screen M. oleifera methanolic leaf (L) extract, seed (S) extract, and a combined leaf/seed extract (2L : 1S ratio) for antidiabetic and antioxidant activities in mice following administration at a dose level of 500 mg/kg of body weight/day. Diabetes was induced by alloxan administration. Mice were treated with the extracts for 1 and 3 months and compared with the appropriate control. At the end of the study period, the mice were euthanized and pancreas, liver, kidney, and blood samples were collected for the analysis of biochemical parameters and histopathology. The oral administration of the combined L/S extract significantly reduced fasting blood glucose to normal levels compared with L or S extracts individually; moreover, a significant decrease in cholesterol, triglycerides, creatinine, liver enzymes, and oxidant markers was observed, with a concomitant increase in antioxidant biomarkers. Thus, the combined extract has stronger antihyperlipidemic and antioxidant properties than the individual extracts. The histopathological results also support the biochemical parameters, showing recovery of the pancreas, liver, and kidney tissue. The effects of the combined L/S extracts persisted throughout the study period tested. To the best of our knowledge, this is the first study to report on the antidiabetic, antioxidant, and antihyperlipidemic effects of a combined L/S extract of M. oleifera in an alloxan-induced diabetic model in mice. Our results suggest the potential for developing a natural potent antidiabetic drug from M. oleifera; however, clinical studies are required.

Complete biosynthetic pathway to the antidiabetic drug acarbose

Acarbose is a bacterial-derived α-glucosidase inhibitor clinically used to treat patients with type 2 diabetes. As type 2 diabetes is on the rise worldwide, the market demand for acarbose has also increased. Despite its significant therapeutic importance, how it is made in nature is not completely understood. Here, we report the complete biosynthetic pathway to acarbose and its structural components, GDP-valienol and O-4-amino-(4,6-dideoxy-α-D-glucopyranosyl)-(1→4)-O-α-D-glucopyranosyl-(1→4)-D-glucopyranose. GDP-valienol is derived from valienol 7-phosphate, catalyzed by three cyclitol modifying enzymes, whereas O-4-amino-(4,6-dideoxy-α-D-glucopyranosyl)-(1→4)-O-α-D-glucopyranosyl-(1→4)-D-glucopyranose is produced from dTDP-4-amino-4,6-dideoxy-D-glucose and maltose by the glycosyltransferase AcbI. The final assembly process is catalyzed by a pseudoglycosyltransferase enzyme, AcbS, which is a homologue of AcbI but catalyzes the formation of a non-glycosidic C-N bond. This study clarifies all previously unknown steps in acarbose biosynthesis and establishes a complete pathway to this high value pharmaceutical.

The market demand for acarbose, a drug used for treatment of patients affected by type-2 diabetes, has increased. In this article, the authors report the acarbose complete biosynthetic pathway, clarifying previously unknown steps and identifying a pseudoglycosyltransferase enzyme, AcbS, a homologue of AcbI that catalyzes the formation of a non-glycosidic C-N bond.

Association of Acarbose with Decreased Muscle Mass and Function in Patients with Type 2 Diabetes: A Retrospective, Cross-Sectional Study

INTRODUCTION

Prevalence of sarcopenia has increased in patients with type 2 diabetes. The influence of glucose-lowering drugs on muscles in these patients remains unclear. We aimed to investigate the association between muscle mass/function and glucose-lowering drugs.

METHODS

Data of 1042 hospitalized patients with type 2 diabetes were included in this retrospective, cross-sectional study. All the patients had stable hypoglycemic therapy in the last 3 months, and performed bioelectrical impedance analysis, grip strength, and gait speed tests on admission.

RESULTS

Skeletal muscle index [6.81 (95% CI 6.67, 6.94) vs. 7.17 (7.09, 7.24) kg/m²], handgrip strength [23.41 (22.24, 24.58) vs. 26.93 (26.33, 27.54) kg], and gait speed [1.19 (1.15, 1.22) vs. 1.27 (1.25, 1.28) m/s] decreased in patients using acarbose compared with the others (all p < 0.001). Gait speed and skeletal muscle index remained lower in patients using acarbose compared to their matched patients in propensity score matching (p = 0.036 and 0.010, respectively). Among drug-naïve patients and patients using insulin, metformin, sulfonylureas, or acarbose monotherapy, the acarbose group had lowest skeletal muscle index and handgrip strength [6.81 (6.52, 7.11) kg/m² and 22.54 (19.28, 25.79) kg, p = 0.028 and 0.001, respectively].

CONCLUSION

Acarbose treatment was associated with decreased muscle mass and strength. Assessment and exercise of muscles in patients with long-term acarbose treatment should be considered.

Linagliptin and cardiovascular outcomes in type 2 diabetes after acute coronary syndrome or acute ischemic stroke

Background

The cardiovascular safety and efficacy of linagliptin, a dipeptidyl peptidase-4 inhibitor, in patients with type 2 diabetes mellitus (T2DM) after acute coronary syndrome (ACS) or acute ischemic stroke (AIS) are unclear. The aim of our real-world cohort study was to evaluate the cardiovascular outcomes of linagliptin in patients with T2DM after ACS or AIS.

Methods

An open observational noncrossover retrospective cohort study was conducted between June 1, 2012 and December 31, 2013 utilizing Taiwan National Health Insurance Research Database. A total of 1203 patients with T2DM after ACS or AIS were selected as the study cohort. Cardiovascular safety and efficacy of linagliptin were evaluated by comparing outcomes of 401 subjects receiving linagliptin after ACS or AIS to 802 matched control subjects not receiving any incretin-based therapy after ACS or AIS. The primary composite outcome included cardiovascular death, non-fatal myocardial infarction and non-fatal ischemic stroke.

Results

The primary composite outcome after 15-month follow-up was 7% (28 patients) in the linagliptin group compared with 6.1% (49 patients) in the control group [hazard ratio (HR) 1.06; 95% confidence interval (CI) .66–1.68]. The linagliptin group also had similar risks of all-cause mortality, hospitalization for heart failure, percutaneous coronary intervention and coronary artery bypass grafting compared to the control group in terms of the secondary outcomes.

Conclusions

In T2DM patients after ACS or AIS, treatment with linagliptin was not associated with increased risks of cardiovascular death, non-fatal myocardial infarction, or non-fatal ischemic stroke.

Comparative assessment of the efficacy and safety of acarbose and metformin combined with premixed insulin in patients with type 2 diabetes mellitus

This study, a subgroup analysis of the data from the Organization Program of DiabEtes INsulIN ManaGement study, aimed to compare the efficacy and safety profiles of acarbose and metformin used in combination with premixed insulin.This analysis included 80 and 192 patients taking only 1 oral antidiabetic drug, classified into acarbose (treated with acarbose + insulin) and metformin groups (treated with metformin + insulin), respectively. The efficacy and safety data were analyzed for within- and between-group differences. The clinical trial registry number was NCT01338376.The percentage of patients who achieved target hemoglobin A1c (HbA1c) <7% in the acarbose and metformin groups were 38.75% and 30.73%, respectively, after a 16-week treatment. The average HbA1c levels in the acarbose and metformin groups were comparable at baseline and decreased significantly in both groups at the end of the study. All 7 blood glucose decreased significantly in both groups at endpoint compared with that at baseline. Insulin consumption was higher in the metformin group in terms of total daily amount and units/kg body weight. Incidences of hypoglycemia were similar in both groups. Body weight changed significantly in both groups from baseline to endpoint, but with no significant difference between the groups. Mean scores of Morisky Medication Adherence Scale improved in both groups at endpoint.Combination of insulin with acarbose or metformin could improve glycemic control in patients with type 2 diabetes mellitus. Acarbose and metformin were found to be comparable in terms of efficacy, weight gain, and incidence of hypoglycemia.

Comparison of acarbose and metformin therapy in newly diagnosed type 2 diabetic patients with overweight and/or obesity

OBJECTIVE

To compare the efficacy of acarbose and metformin in overweight and/or obese patients with newly diagnosed type 2 diabetes mellitus (T2DM).

METHODS

A total of 108 drug-naïve patients with newly diagnosed T2DM, whose hemoglobin A1c (HbA1c) was between 7% and 10% and body mass index was greater than 24 kg/m(2), were enrolled in the First People's Hospital and Municipal Central Hospital of Xiangtan City, Xiangtan, China, from 1 February 2010 to 1 August 2011. Patients were randomly assigned to acarbose (100 mg three times a day) and metformin (1.5 g/day) groups for a predictive follow-up period of 24 weeks. Plasma glucose, insulin, and glucagons at 0, 0.5, and 2 hours after a standardized meal, and HbA1c were measured at baseline and 24 weeks.

RESULTS

Baseline characteristics of the acarbose and metformin groups were similar. Glucose control improved significantly in both groups at 24 weeks. The percentage of patients achieving HbA1C <6.5% was comparable for acarbose and metformin therapy at 24 weeks. Body weight reduction from baseline to 24 weeks was 3.3 kg in the acarbose group and 2.7 kg in the metformin group, whereas the change in HbA1c and body weight was similar in both groups. The early-phase insulin secretion index improved only in the acarbose group at 24 weeks. After 24 weeks of therapy, fasting glucagon and 0.5 hour postprandial glucagon levels decreased markedly in the acarbose group compared to the metformin group.

CONCLUSIONS

Twenty-four weeks of therapy with acarbose and metformin induced similar reductions in HbA1c and body weight, but acarbose showed superior efficacy in improving islet α-cell function compared with metformin in overweight/obese patients with newly diagnosed T2DM. However, more large-sample, multicenter, randomized controlled trials are needed to evaluate the efficacy, safety, cost-effectiveness, and glycemic variability of the two drugs.

Metformin and metabolic diseases: a focus on hepatic aspects

Metformin has been widely used as a first-line anti-diabetic medicine for the treatment of type 2 diabetes (T2D). As a drug that primarily targets the liver, metformin suppresses hepatic glucose production (HGP), serving as the main mechanism by which metformin improves hyperglycemia of T2D. Biochemically, metformin suppresses gluconeogenesis and stimulates glycolysis. Metformin also inhibits glycogenolysis, which is a pathway that critically contributes to elevated HGP. While generating beneficial effects on hyperglycemia, metformin also improves insulin resistance and corrects dyslipidemia in patients with T2D. These beneficial effects of metformin implicate a role for metformin in managing non-alcoholic fatty liver disease. As supported by the results from both human and animal studies, metformin improves hepatic steatosis and suppresses liver inflammation. Mechanistically, the beneficial effects of metformin on hepatic aspects are mediated through both adenosine monophosphate-activated protein kinase (AMPK)-dependent and AMPK-independent pathways. In addition, metformin is generally safe and may also benefit patients with other chronic liver diseases.