Alpha-glucosidase inhibitors for prevention or delay of type 2 diabetes mellitus and its associated complications in people at increased risk of developing type 2 diabetes mellitus

In silico exploration of the potential inhibitory activities of in-house and ZINC database lead compounds against alpha-glucosidase using structure-based virtual screening and molecular dynamics simulation approach

Inhibitors of α-glucosidase have been used to treat type-2 diabetes (T2DM) by preventing the breakdown of carbohydrates into glucose and prevent enhancing glucose conversion. Structure-based virtual screening (SBVS) was used to generate novel chemical scaffold-ligand α-glucosidase inhibitors. The databases were screened against the receptor α-glucosidase using SBVS and molecular dynamics simulation (MDS) techniques in this study. Based on molecular docking studies, three and two compounds of α-glucosidase inhibitors were chosen from a commercial database (ZINC) and an In-house database for this study respectively. The mode of binding interactions of the selected compounds later predicted their α-glucosidase inhibitory potential. Finally, one out of three lead compound from ZINC and one out of two lead compound from In-house database were shortlisted based on interactions. Furthermore, MDS and post-MDS strategies were used to refine and validate the shortlisted leads along with the reference acarbose/α-glucosidase. The Hits' ability to inhibit α-glucosidase was predicted by SBVS, indicating that these compounds have good inhibitory activities. The lead inhibitor's structure may serve as templates for the design of novel inhibitors, and in vitro testing to confirm their anti-diabetic potential is necessary. These insights can help rationally design new effective anti-diabetic drugs.

Kigelia africana fruit fractions inhibit in vitro alpha-glucosidase activity: a potential natural alpha-glucosidase inhibitor

BACKGROUND

Diabetes affects 75% of people in low-income countries, where conventional drugs like metformin are available, but newer drugs like alpha-glucosidase inhibitors are not accessible to most Southern African patients.

AIM

To evaluate the α-glucosidase and α-amylase inhibitory activities of fractionated aqueous extracts of Kigelia africana fruit (KAFE) and their phytochemical fingerprints using gas chromatography-mass spectrometry (GC-MS).

MATERIALS AND METHODS

We studied K. africana fruit fractions' inhibitory effects on alpha-glucosidase and alpha-amylase using bioassay-guided fractionation, and analyzed their phytochemical profiles with GC-MS.

KEY FINDINGS

Both the aqueous extract and ethyl acetate fraction of the aqueous extract exhibited a low dose-dependent inhibition of alpha-amylase activity (p < 0.0001). At a concentration of 500 μg/mL, the aqueous extract caused an alpha-glucosidase inhibition of 64.10 ± 2.7%, with an estimated IC50 of 193.7 μg/mL, while the ethyl acetate fraction had an inhibition of 89.82 ± 0.8% and an estimated IC50 of 10.41 μg/mL. The subfraction G, which had the highest alpha-glucosidase inhibitory activity at 85.10 ± 0.7%, had significantly lower activity than the ethyl acetate fraction. The most bioactive fraction was found to contain 11"(2-cyclopenten-1-yl) undecanoic acid, ( +)- and cyclopentane undecanoic acid as well as the indole alkaloids Akuammilan-17-ol-10-methoxy, N-nitroso-2-methyl-oxazolidine and epoxide Oxirane2.2″ -(1.4-butanediyl) bis-.

CONCLUSION

The K. africana fruit fraction demonstrated significant alpha-glucosidase inhibitory activity, while its alpha-amylase inhibitory activity was limited. This study suggests a potential natural alpha-glucosidase inhibitor and phytocompounds that could serve as leads for developing antidiabetic agents.

Association between dietary glycemic index and non-alcoholic fatty liver disease in patients with type 2 diabetes mellitus

Objective

Managing dietary glycemic index (GI) deserves further attention in the interplay between non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM). This study aimed to evaluate the relationship between dietary GI and the odds of NAFLD in patients with T2DM.

Methods

A cross-sectional study was carried out between April 2021 and February 2022, including 200 participants with T2DM aged 18-70 years, of which 133 had NAFLD and 67 were in the non-NAFLD group. Cardiometabolic parameters were analyzed using standard biochemical kits and dietary intake was assessed using a validated food frequency questionnaire. Binary logistic regression was applied to explore odds ratios (ORs) and 95% confidence intervals (CIs) for NAFLD according to tertiles of dietary GI.

Results

Highest vs. lowest tertile (< 57 vs. > 60.89) of energy-adjusted GI was not associated with the odds of having NAFLD (OR 1.25, 95% CI = 0.6-2.57; P-trend = 0.54) in the crude model. However, there was an OR of 3.24 (95% CI = 1.03-10.15) accompanied by a significant trend (P-trend = 0.04) after full control for potential confounders (age, gender, smoking status, duration of diabetes, physical activity, waist circumference, HbA1c, triglycerides, total cholesterol, dietary intake of total carbohydrates, simple carbohydrates, fat, and protein).

Conclusion

High dietary GI is associated with increased odds of NAFLD in subjects with T2DM. However, interventional and longitudinal cohort studies are required to confirm these findings.

Capsicum annuum L. cv. DANGJO ameliorated hyperglycemia in type 2 diabetes animal model induced by high-fat diet and streptozotocin

In this study, it was evaluated the effect of freeze-dried powder of Capsicum annuum L. cv. DANGJO (DJ) on ameliorating hyperglycemia in type 2 diabetes rat model induced by high-fat diet (HFD) and streptozotocin (STZ). Oral administration of DJ significantly reduced non-fasting blood glucose (NFBG) and insulin levels, as well as glycated hemoglobin (HbA1c) level, a representative marker for diabetes, in HFD/STZ treated rats whereas the administration of green hot pepper (GHP) and green sweet pepper (GSP) did not show the significant effect. Quercitrin was quantified (40.97 mg/100 g of DJ) by HPLC, and administration of the same amount of quercitrin with DJ exerted the significant reduction of blood glucose level, strongly supporting that quercitrin is the key component in ameliorating the hyperglycemia of DJ in HFD/STZ treated rats. These results suggest that DJ can be considered as a potent functional food in preventing hyperglycemia in type 2 diabetes mellitus.

Influence of Hospital Formularies on Outpatient Prescribing Practices: Analysis of the Introduction of a Local Formulary: A Single-Center, 2-Year Follow-Up, Retrospective Cohort Study of a Local Formulary in Japan

PURPOSE

The impact of a hospital formulary was evaluated to provide a guide for the establishment of local formularies to optimize patient care and healthcare costs.

METHODS

A formulary was introduced by formulary pharmacists of the Toda Medical Group for suggesting recommended medicines to physicians based on the medication history. Patients who were hospitalized in the rehabilitation ward of the Niiza Hospital and prescribed medicines according to the formulary introduced between April 2017 and March 2018 were included and followed-up for six months.

RESULTS

Of the 183 patients screened, 154 patients were enrolled as the formulary's introduction patients (76 males/78 females, median age 78 years); 92% of these patients received formulary-proposed prescriptions at the specified timepoints; and 19 patients re-consulted at the Niiza Hospital after discharge and continued the same formulary medicines. The proposed acceptance rate by physicians was 100%. Most changes suggested introduced generic formulations. The doses were equivalent for all pharmacological classes with the exception of medicines that interfere with the renin-angiotensin system, which fell from 10.7 to 7.2 mg (P< .0001). Overall daily medication costs fell at discharge compared to admission (38.5 vs. 94.6 yen per patient, respectively, P< .0001). This was valid for all pharmacological classes except for calcium channel blockers.

CONCLUSION

Hospital formulary-prescribed medications continued after discharge and promoted significant decreases in costs associated with outpatient prescriptions. Introducing a hospital formulary provides a basis for the introduction of local formularies and contributes to the reduction of local healthcare costs.

Identifying potential therapeutic targets of Tang-Yi-Ping for the treatment of impaired glucose tolerance: a tandem mass tag-labeled quantitative proteomic analysis

Background

This study uses the tandem mass tag (TMT)-labeled quantitative proteomic analysis to identify potential therapeutic protein targets of a Chinese prescription called Tang-Yi-Ping (TYP) for the treatment of impaired glucose tolerance (IGT) in rats.

Methods

A total of 31 specific-pathogen free (SPF) male Wistar rats were used in our study. Ten were randomly selected as a control group, while 21 received a high-sugar and high-fat diet combined with an intraperitoneal injection of streptozotocin to establish IGT subjects. After eliminating 2 rats without successful modeling, 19 were randomly divided into a TYP group (n=9) and IGT model group (n=10). The TYP group was given a TYP decoction of 6.36 mg/kg−1/d−1. After 8 weeks of intervention, blood glucose-related indicators were measured, and cell morphology was observed by hematoxylin and eosin (HE) staining. TMT-labeled proteomic analysis was applied to detect the differentially expressed proteins (DEPs) in the pancreases of the three groups. The intersection of the DEPs in both the TYP group and IGT model group underwent Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses to identify the related biological functions and signal transduction pathways. Finally, western blot (WB) was used to verify the TMT proteomics results.

Results

TYP can effectively reduce blood glucose and improve islet morphology in IGT rats. We identified a total of 16 potential therapeutic protein targets of TYP, 4 of which were upregulated, while 12 were downregulated, including Rbp4, Fam3b, Flot2, etc. [fold change (FC) >1.1, P<0.05]. The significant signal transduction pathways included arginine and proline metabolism, glyceride metabolism, glycerophospholipid metabolism, mTOR, Wnt, and insulin signaling pathways.

Conclusions

For anti-IGT therapy, we found TYP regulates 16 protein targets, multiple biological functions, and multiple signal transduction pathways. This study thus makes a significant contribution to identifying new potential therapeutic targets for treating IGT.

The effect of oat β-glucan on postprandial blood glucose and insulin responses: a systematic review and meta-analysis

To determine the effect of oat β‑glucan (OBG) on acute glucose and insulin responses and identify significant effect modifiers we searched the MEDLINE, EMBASE, and Cochrane databases through October 27, 2020 for acute, crossover, controlled feeding trials investigating the effect of adding OBG (concentrate or oat-bran) to carbohydrate-containing test-meals compared to comparable or different carbohydrate-matched control-meals in humans regardless of health status. The primary outcome was glucose incremental area-under-the-curve (iAUC). Secondary outcomes were insulin iAUC, and glucose and insulin incremental peak-rise (iPeak). Two reviewers extracted the data and assessed risk-of-bias and certainty-of-evidence (GRADE). Data were pooled using generic inverse-variance with random-effects model and expressed as ratio-of-means with [95% CIs]. We included 103 trial comparisons (N = 538). OBG reduced glucose iAUC and iPeak by 23% (0.77 [0.74, 0.81]) and 28% (0.72 [0.64, 0.76]) and insulin by 22% (0.78 [0.72, 0.85]) and 24% (0.76 [0.65, 0.88]), respectively. Dose, molecular-weight, and comparator were significant effect modifiers of glucose iAUC and iPeak. Significant linear dose-response relationships were observed for all outcomes. OBG molecular-weight >300 kg/mol significantly reduced glucose iAUC and iPeak, whereas molecular-weight <300 kg/mol did not. Reductions in glucose iAUC (27 vs 20%, p = 0.03) and iPeak (39 vs 25%, p < 0.01) were significantly larger with different vs comparable control-meals. Outcomes were similar in participants with and without diabetes. All outcomes had high certainty-of-evidence. In conclusion, current evidence indicates that adding OBG to carbohydrate-containing meals reduces glycaemic and insulinaemic responses. However, the magnitude of glucose reduction depends on OBG dose, molecular-weight, and the comparator.

Evaluation and treatment of peripheral nervous system dysfunction in patients with prediabetes

The worldwide prevalence of prediabetes is steadily increasing, with up to a third of patients already showing signs of diabetic neuropathy (DN). Prediabetes includes impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or a combination of both.

Recent diagnostic criteria of prediabetes according to Russian, European, and American clinical guidelines are presented. The review covers the most common forms of DN in patients with prediabetes (distal symmetric sensory polyneuropathy, painful DN, cardiovascular autonomic neuropathy) and their prevalence. Recommended methods of DN screening are discussed: diagnostic scales, sensory testing, nerve conduction study, autonomic testing, corneal confocal microscopy. The results of studies evaluating instrumental methods for diagnosing peripheral nervous system (PNS) dysfunction in prediabetes are discussed. Management tactics in patients with prediabetes and PNS dysfunction should include non-pharmacological and pharmacological interventions. Combining a low-calorie diet and regular physical activity can delay the development of diabetes mellitus and reduce the severity of neuropathic pain. In patients with painful DN, the first-line therapy includes pregabalin, gabapentin, and duloxetine. Since there is no current data on the effect of hypoglycemic therapy on the risks of development and/or progression of DN in patients with prediabetes, antioxidants are considered pathogenetic therapy. Alpha-lipoic acid (Berlition®) in the management of patients with prediabetes is discussed.

Agriophyllum Oligosaccharides Ameliorate Diabetic Insulin Resistance Through INS-R/IRS/Glut4-Mediated Insulin Pathway in db/db Mice and MIN6 Cells

We have previously reported that Agriophyllum oligosaccharides (AOS) significantly enhance glycemic control by increasing the activation of insulin receptor (INS-R), insulin receptor substrate-2 (IRS-2), phosphatidylinositol 3 kinase (PI3K), protein kinase B (AKT), peroxisome proliferator-activated receptor (PPAR)-γ, and glucose transporter 4 (Glut4) proteins in hepatic tissues. However, the effect of glucose control by AOS on the regulation of pancreatic tissues in db/db mice and MIN6 cells remains to be determined. An oral dose of AOS (380 or 750 mg/kg) was administered to type-2 diabetic db/db mice for 8 weeks to determine whether AOS regulates glucose by the INS-R/IRS/Glut4-mediated insulin pathway. Meanwhile, the effects of AOS on glucose uptake and its related signaling pathway in MIN6 cells were also investigated. The results showed that the random blood glucose (RBG) level in the AOS-treated group was lower than that in the control group. AOS reduced the levels of glycated hemoglobin (HbA1c) and free fatty acid (FFA) and significantly improved the pathological changes in the pancreatic tissues in db/db mice. Moreover, immunohistochemical analysis revealed that the expression of INS-R, IRS-1, IRS-2, and Glut4 was increased in the AOS-treated group than in the model group. Further, in vitro experiments using MIN6 cells showed that AOS regulated INS-R, IRS-1, IRS-2, and Glut4 protein and mRNA levels and attenuated insulin resistance and cell apoptosis. The results of both in vitro and in vivo experiments were comparable. Ultra-performance liquid chromatography coupled with time-of-flight mass spectrometric analysis of AOS with precolumn derivatization with 3-amino-9-ethylcarbazole (AEC) tentatively identified five types of sugars: glucose, lactose, rutinose, glucuronic acid, and maltotriose. Our present study clearly showed that AOS is efficacious in preventing hyperglycemia, possibly by increasing insulin sensitivity and improving IR by regulating the INS-R/IRS/Glut4 insulin signal pathway. Therefore, AOS may be considered as a potential drug for diabetes treatment.

Diabetes medications as potential calorie restriction mimetics-a focus on the alpha-glucosidase inhibitor acarbose

The field of aging research has grown rapidly over the last half-century, with advancement of scientific technologies to interrogate mechanisms underlying the benefit of life-extending interventions like calorie restriction (CR). Coincident with this increase in knowledge has been the rise of obesity and type 2 diabetes (T2D), both associated with increased morbidity and mortality. Given the difficulty in practicing long-term CR, a search for compounds (CR mimetics) which could recapitulate the health and longevity benefits without requiring food intake reductions was proposed. Alpha-glucosidase inhibitors (AGIs) are compounds that function predominantly within the gastrointestinal tract to inhibit α-glucosidase and α-amylase enzymatic digestion of complex carbohydrates, delaying and decreasing monosaccharide uptake from the gut in the treatment of T2D. Acarbose, an AGI, has been shown in pre-clinical models to increase lifespan (greater longevity benefits in males), with decreased body weight gain independent of calorie intake reduction. The CR mimetic benefits of acarbose are further supported by clinical findings beyond T2D including the risk for other age-related diseases (e.g., cancer, cardiovascular). Open questions remain regarding the exclusivity of acarbose relative to other AGIs, potential off-target effects, and combination with other therapies for healthy aging and longevity extension. Given the promising results in pre-clinical models (even in the absence of T2D), a unique mechanism of action and multiple age-related reduced disease risks that have been reported with acarbose, support for clinical trials with acarbose focusing on aging-related outcomes and incorporating biological sex, age at treatment initiation, and T2D-dependence within the design is warranted.

Diabetes medications as potential calorie restriction mimetics-a focus on the alpha-glucosidase inhibitor acarbose

The field of aging research has grown rapidly over the last half-century, with advancement of scientific technologies to interrogate mechanisms underlying the benefit of life-extending interventions like calorie restriction (CR). Coincident with this increase in knowledge has been the rise of obesity and type 2 diabetes (T2D), both associated with increased morbidity and mortality. Given the difficulty in practicing long-term CR, a search for compounds (CR mimetics) which could recapitulate the health and longevity benefits without requiring food intake reductions was proposed. Alpha-glucosidase inhibitors (AGIs) are compounds that function predominantly within the gastrointestinal tract to inhibit α-glucosidase and α-amylase enzymatic digestion of complex carbohydrates, delaying and decreasing monosaccharide uptake from the gut in the treatment of T2D. Acarbose, an AGI, has been shown in pre-clinical models to increase lifespan (greater longevity benefits in males), with decreased body weight gain independent of calorie intake reduction. The CR mimetic benefits of acarbose are further supported by clinical findings beyond T2D including the risk for other age-related diseases (e.g., cancer, cardiovascular). Open questions remain regarding the exclusivity of acarbose relative to other AGIs, potential off-target effects, and combination with other therapies for healthy aging and longevity extension. Given the promising results in pre-clinical models (even in the absence of T2D), a unique mechanism of action and multiple age-related reduced disease risks that have been reported with acarbose, support for clinical trials with acarbose focusing on aging-related outcomes and incorporating biological sex, age at treatment initiation, and T2D-dependence within the design is warranted.

[Treatment of diabetes mellitus in perioperative medicine-an update]

Patients with diabetes who undergo a surgical intervention have an increased risk of metabolic derailment, anesthesiological complications, postoperative infections and cardiovascular events. The treatment of diabetes mellitus is subject to a continuous further development due to pharmaceutical and technical innovations. This article presents the implications of the current concepts of diabetes treatment for perioperative medicine, particularly the changes due to new oral antidiabetic agents and insulin pump treatment. Some of the currently available guidelines are discussed with respect to the care of diabetes patients in childhood and adulthood in connection with an operation. Finally, possible perspectives in the field of monitoring and treatment of diabetes patients are discussed.

Rational Design of Novel Inhibitors of α-Glucosidase: An Application of Quantitative Structure Activity Relationship and Structure-Based Virtual Screening

α-Glucosidase is considered a prime drug target for Diabetes Mellitus and its inhibitors are used to delay carbohydrate digestion for the treatment of diabetes mellitus. With the aim to design α-glucosidase inhibitors with novel chemical scaffolds, three folds ligand and structure based virtual screening was applied. Initially linear quantitative structure activity relationship (QSAR) model was developed by a molecular operating environment (MOE) using a training set of thirty-two known inhibitors, which showed good correlation coefficient (r² = 0.88), low root mean square error (RMSE = 0.23), and cross-validated correlation coefficient r² (q² = 0.71 and RMSE = 0.31). The model was validated by predicting the biological activities of the test set which depicted r² value of 0.82, indicating the robustness of the model. For virtual screening, compounds were retrieved from zinc is not commercial (ZINC) database and screened by molecular docking. The best docked compounds were chosen to assess their pharmacokinetic behavior. Later, the α-glucosidase inhibitory potential of the selected compounds was predicted by their mode of binding interactions. The predicted pharmacokinetic profile, docking scores and protein-ligand interactions revealed that eight compounds preferentially target the catalytic site of α-glucosidase thus exhibit potential α-glucosidase inhibition in silico. The α-glucosidase inhibitory activities of those Hits were predicted by QSAR model, which reflect good inhibitory activities of these compounds. These results serve as a guidelines for the rational drug design and development of potential novel anti-diabetic agents.

ZG02 Improved Hepatic Glucose Metabolism and Insulin Sensitivity via Activation of AMPK/Sirt1 Signaling Pathways in a High-fat Diet/Streptozotocin-induced Type 2 Diabetes Model

PURPOSE

The aim of the present study was to investigate the hypoglycemic activity and potential mechanism of tetrahydrocarbazole derivatives ZG02 in high-fat diet/streptozotocin-induced type 2 diabetes model.

METHODS

C57BL/6 mice (n=30) were randomly assigned to three groups: control group (n=10) was fed with normal diet, the diabetes group (n=10) was fed with high-fat diet for eight weeks followed by intraperitoneal injection of streptozotocin (25 mg/kg) and the ZG02 group (n=10) injected intraperitoneally with ZG02 (30 mg/kg/day) for two weeks after successful modeling. The changes of weight, fasting blood glucose, oral glucose tolerance and fasting blood insulin levels in each group were evaluated. In addition, we also assessed the expression level of total AMPK, phosphorylation AMPK, SIRT1, PGC-1 and the activity of G6PC in liver.

RESULTS

The results demonstrated that ZG02 could significantly antagonize the high-fat diet/streptozotocin-induced fasting hyperglycemia, restore fasting blood insulin levels and also improve activity of G6PC in liver. The results from Western blot indicated that ZG02 significantly restored the expression level of phosphorylation AMPK, Sirt1 and PGC-1.

CONCLUSION

ZG02 improve hepatic glucose metabolism and insulin sensitivity via activation AMPK/Sirt1 signaling pathways in type 2 diabetes mice model.

Acarbose has sex-dependent and -independent effects on age-related physical function, cardiac health, and lipid biology

With an expanding aging population burdened with comorbidities, there is considerable interest in treatments that optimize health in later life. Acarbose (ACA), a drug used clinically to treat type 2 diabetes mellitus (T2DM), can extend mouse life span with greater effect in males than in females. Using a genetically heterogeneous mouse model, we tested the ability of ACA to ameliorate functional, pathological, and biochemical changes that occur during aging, and we determined which of the effects of age and drug were sex dependent. In both sexes, ACA prevented age-dependent loss of body mass, in addition to improving balance/coordination on an accelerating rotarod, rotarod endurance, and grip strength test. Age-related cardiac hypertrophy was seen only in male mice, and this male-specific aging effect was attenuated by ACA. ACA-sensitive cardiac changes were associated with reduced activation of cardiac growth-promoting pathways and increased abundance of peroxisomal proteins involved in lipid metabolism. ACA further ameliorated age-associated changes in cardiac lipid species, particularly lysophospholipids - changes that have previously been associated with aging, cardiac dysfunction, and cardiovascular disease in humans. In the liver, ACA had pronounced effects on lipid handling in both sexes, reducing hepatic lipidosis during aging and shifting the liver lipidome in adulthood, particularly favoring reduced triglyceride (TAG) accumulation. Our results demonstrate that ACA, already in clinical use for T2DM, has broad-ranging antiaging effects in multiple tissues, and it may have the potential to increase physical function and alter lipid biology to preserve or improve health at older ages.

Gamma-Polyglutamic Acid-Rich Natto Suppresses Postprandial Blood Glucose Response in the Early Phase after Meals: A Randomized Crossover Study

We evaluated the suppressive effects of high-gamma-polyglutamic acid (γ-PGA) natto on postprandial blood glucose level and insulin response. After confirming the eligibility of candidates using a pre-selective test with packaged white rice, a meal loading test including low- or high-γ-PGA natto (with 57.6 mg (LPGA) and 439.6 mg (HPGA) of γ-PGA, respectively) was conducted in men aged 20 to 70 years (n = 29) and postmenopausal women aged ≤70 years (n = 7). On each examination day, blood samples were obtained after they fasted overnight and for 120 min after test meal loading. The primary outcome of this study was the difference between the measurements of the incremental area under the curve (IAUC) for blood glucose 0 to 30 min after loading of LPGA and HPGA meals. The IAUCs for blood glucose and insulin after the HPGA meal were lower than those after the LPGA meal within 45 min (0 to 15 and 0 to 30 min: p < 0.001, 0 to 45 min: p < 0.01) and 1 h (all p < 0.001) of loading, respectively. The suppressive effects of HPGA natto on postprandial glucose response in the early phase, which possibly relates to the risk of dysglycemia and cardiovascular disease, were clarified.

The Potential of Anti-Diabetic Rākau Rongoā (Māori Herbal Medicine) to Treat Type 2 Diabetes Mellitus (T2DM) Mate Huka: A Review

T2DM (type 2 diabetes mellitus, or Māori term “mate huka”) is a major long-term health issue in New Zealand particularly among the Māori community. Non-insulin drugs commonly used in New Zealand for the treatment of T2DM have limits to their efficacy as well as side effects, which are of concern for diabetics. As such, the potential for natural products such as traditional rākau rongoā are of interest for potentially preventing the development of T2DM or improving the treatment of the disease. In particular, anti-diabetic effects have been reported for rākau rongoā such as karamu, kūmarahou, and kawakawa. Natural products have been identified in karamu, kūmarahou, and kawakawa that have documented potential effects on glucose metabolism that could contribute to the anti-diabetic effect of these rākau rongoā. As such, this could provide scientific insight into the mātauranga (traditional knowledge) developed over generations by Māori. However, detailed laboratory based and clinical studies would be required to understand and validate these properties of karamu, kūmarahou, and kawakawa, and to understand how they can be used in T2DM treatment. Social determinants of indigenous health such as language, culture, traditional knowledge, and identity, are important in understanding the relationship Māori have with their land and the mātauranga they developed of the medicinal properties within their rākau rongoā, over many centuries. Interestingly, traditional Māori views towards scientific research using animal models to test rākau rongoā are varied but supportive. Furthermore, cultural issues surrounding Māori mana motuhake (self-determination) of traditional rongoā Māori healing practices and the inequity faced by many kairongoā (rongoā Māori practitioners) and tohunga (healers) compared to mainstream health are a current issue within the New Zealand health system. As such, a cultural holistic approach for T2DM care among Māori would be advantageous. This review will outline the available evidence supporting the anti-diabetic efficacy of karamu, kūmarahou, and kawakawa. Currently though there is a lack of molecular research to understand the mechanisms of this efficacy, as such this review will also outline Te Reo Tipu Research, a kaupapa Māori framework for molecular and genomic research on taonga flora.

Steamed Ginger May Enhance Insulin Secretion through KATP Channel Closure in Pancreatic β-Cells Potentially by Increasing 1-Dehydro-6-Gingerdione Content

Ginger (Zingiber officinale Roscoe) and its active compounds (gingerols, shogaols and paradols) have been reported as having beneficial functions for several diseases, including diabetes. In this study, we revealed that the steaming process could enhance the anti-diabetic potential of ginger. To confirm the anti-diabetic effect of steamed ginger extract (GG03), we assessed pancreatic islets impaired by alloxan in zebrafish and demonstrated anti-hyperglycemic efficacy in a mouse model. The EC50 values of ginger extract (GE) and GG03 showed that the efficacy of GG03 was greater than that of GE. In addition, LC50 values demonstrated that GG03 had lower toxicity than GE, and the comparison of the Therapeutic Index (TI) proved that GG03 is a safer functional food. Furthermore, our data showed that GG03 significantly lowered hyperglycemia in a diabetic mouse model. HPLC was performed to confirm the change in the composition of steamed ginger. Interestingly, GG03 showed a 375% increase in 1-dehydro-6-gingerdione (GD) compared with GE. GD has not yet been studied much pharmacologically. Thus, we identified the protective effects of GD in the damaged pancreatic islets of diabetic zebrafish. We further assessed whether the anti-diabetic mechanism of action of GG03 and GD involves insulin secretion. Our results suggest that GG03 and GD might stimulate insulin secretion by the closure of KATP channels in pancreatic β-cells.

Metformin for prevention or delay of type 2 diabetes mellitus and its associated complications in persons at increased risk for the development of type 2 diabetes mellitus

BACKGROUND

The projected rise in the incidence of type 2 diabetes mellitus (T2DM) could develop into a substantial health problem worldwide. Whether metformin can prevent or delay T2DM and its complications in people with increased risk of developing T2DM is unknown.

OBJECTIVES

To assess the effects of metformin for the prevention or delay of T2DM and its associated complications in persons at increased risk for the T2DM.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Scopus, ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform and the reference lists of systematic reviews, articles and health technology assessment reports. We asked investigators of the included trials for information about additional trials. The date of the last search of all databases was March 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with a duration of one year or more comparing metformin with any pharmacological glucose-lowering intervention, behaviour-changing intervention, placebo or standard care in people with impaired glucose tolerance, impaired fasting glucose, moderately elevated glycosylated haemoglobin A1c (HbA1c) or combinations of these.

DATA COLLECTION AND ANALYSIS

Two review authors read all abstracts and full-text articles and records, assessed risk of bias and extracted outcome data independently. We used a random-effects model to perform meta-analysis and calculated risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, using 95% confidence intervals (CIs) for effect estimates. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 20 RCTs randomising 6774 participants. One trial contributed 48% of all participants. The duration of intervention in the trials varied from one to five years. We judged none of the trials to be at low risk of bias in all 'Risk of bias' domains. Our main outcome measures were all-cause mortality, incidence of T2DM, serious adverse events (SAEs), cardiovascular mortality, non-fatal myocardial infarction or stroke, health-related quality of life and socioeconomic effects.The following comparisons mostly reported only a fraction of our main outcome set. Fifteen RCTs compared metformin with diet and exercise with or without placebo: all-cause mortality was 7/1353 versus 7/1480 (RR 1.11, 95% CI 0.41 to 3.01; P = 0.83; 2833 participants, 5 trials; very low-quality evidence); incidence of T2DM was 324/1751 versus 529/1881 participants (RR 0.50, 95% CI 0.38 to 0.65; P < 0.001; 3632 participants, 12 trials; moderate-quality evidence); the reporting of SAEs was insufficient and diverse and meta-analysis could not be performed (reported numbers were 4/118 versus 2/191; 309 participants; 4 trials; very low-quality evidence); cardiovascular mortality was 1/1073 versus 4/1082 (2416 participants; 2 trials; very low-quality evidence). One trial reported no clear difference in health-related quality of life after 3.2 years of follow-up (very low-quality evidence). Two trials estimated the direct medical costs (DMC) per participant for metformin varying from $220 to $1177 versus $61 to $184 in the comparator group (2416 participants; 2 trials; low-quality evidence). Eight RCTs compared metformin with intensive diet and exercise: all-cause mortality was 7/1278 versus 4/1272 (RR 1.61, 95% CI 0.50 to 5.23; P = 0.43; 2550 participants, 4 trials; very low-quality evidence); incidence of T2DM was 304/1455 versus 251/1505 (RR 0.80, 95% CI 0.47 to 1.37; P = 0.42; 2960 participants, 7 trials; moderate-quality evidence); the reporting of SAEs was sparse and meta-analysis could not be performed (one trial reported 1/44 in the metformin group versus 0/36 in the intensive exercise and diet group with SAEs). One trial reported that 1/1073 participants in the metformin group compared with 2/1079 participants in the comparator group died from cardiovascular causes. One trial reported that no participant died due to cardiovascular causes (very low-quality evidence). Two trials estimated the DMC per participant for metformin varying from $220 to $1177 versus $225 to $3628 in the comparator group (2400 participants; 2 trials; very low-quality evidence). Three RCTs compared metformin with acarbose: all-cause mortality was 1/44 versus 0/45 (89 participants; 1 trial; very low-quality evidence); incidence of T2DM was 12/147 versus 7/148 (RR 1.72, 95% CI 0.72 to 4.14; P = 0.22; 295 participants; 3 trials; low-quality evidence); SAEs were 1/51 versus 2/50 (101 participants; 1 trial; very low-quality evidence). Three RCTs compared metformin with thiazolidinediones: incidence of T2DM was 9/161 versus 9/159 (RR 0.99, 95% CI 0.41 to 2.40; P = 0.98; 320 participants; 3 trials; low-quality evidence). SAEs were 3/45 versus 0/41 (86 participants; 1 trial; very low-quality evidence). Three RCTs compared metformin plus intensive diet and exercise with identical intensive diet and exercise: all-cause mortality was 1/121 versus 1/120 participants (450 participants; 2 trials; very low-quality evidence); incidence of T2DM was 48/166 versus 53/166 (RR 0.55, 95% CI 0.10 to 2.92; P = 0.49; 332 participants; 2 trials; very low-quality evidence). One trial estimated the DMC of metformin plus intensive diet and exercise to be $270 per participant compared with $225 in the comparator group (94 participants; 1 trial; very-low quality evidence). One trial in 45 participants compared metformin with a sulphonylurea. The trial reported no patient-important outcomes. For all comparisons there were no data on non-fatal myocardial infarction, non-fatal stroke or microvascular complications. We identified 11 ongoing trials which potentially could provide data of interest for this review. These trials will add a total of 17,853 participants in future updates of this review.

AUTHORS' CONCLUSIONS

Metformin compared with placebo or diet and exercise reduced or delayed the risk of T2DM in people at increased risk for the development of T2DM (moderate-quality evidence). However, metformin compared to intensive diet and exercise did not reduce or delay the risk of T2DM (moderate-quality evidence). Likewise, the combination of metformin and intensive diet and exercise compared to intensive diet and exercise only neither showed an advantage or disadvantage regarding the development of T2DM (very low-quality evidence). Data on patient-important outcomes such as mortality, macrovascular and microvascular diabetic complications and health-related quality of life were sparse or missing.

Meta-analysis of the impact of alpha-glucosidase inhibitors on incident diabetes and cardiovascular outcomes

Background

Alpha-glucosidase inhibitors (AGIs) have been shown to reduce incident type 2 diabetes but their impact on cardiovascular (CV) disease remains controversial. We sought to identify the overall impact of AGIs with respect to incident type 2 diabetes in individuals with impaired glucose tolerance (IGT), and CV outcomes in those with IGT or type 2 diabetes.

Methods

We used PubMed and SCOPUS to identify randomized controlled trials reporting the incidence of type 2 diabetes and/or CV outcomes that had compared AGIs with placebo in populations with IGT or type 2 diabetes, with or without established CV disease. Eligible studies were required to have ≥ 500 participants and/or ≥ 100 endpoints of interest. Meta-analyses of available trial data were performed using random effects models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for incident type 2 diabetes and CV outcomes.

Results

Of ten trials identified, three met our inclusion criteria for incident type 2 diabetes and four were eligible for CV outcomes. The overall HR (95% CI) comparing AGI with placebo for incident type 2 diabetes was 0.77 (0.67–0.88), p < 0.0001, and for CV outcomes was 0.98 (0.89–1.10), p = 0.85. There was little to no heterogeneity between studies, with I² values of 0.03% (p = 0.43) and 0% (p = 0.79) for the two outcomes respectively.

Conclusions

Allocation of people with IGT to an AGI significantly reduced their risk of incident type 2 diabetes by 23%, whereas in those with IGT or type 2 diabetes the impact on CV outcomes was neutral.

Anti-diabetic agents for prevention of type 2 diabetes mellitus in people with pre-diabetes: a systematic review and network meta-analysis protocol

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is a substantial health problem worldwide. Pre-diabetic state is associated with increased risk for the development of diabetes. There are various pharmacological therapies with glucose-lowering activity for diabetes prevention. Of those, most are being compared with placebo instead of active agents. The relative effects and safety of different glucose-lowering drugs still remain uncertain. To address this gap, we will conduct a systematic review and network meta-analysis (NMA) to evaluate comparative efficacy and safety of glucose-lowering agents for T2DM prevention in patients with pre-diabetes.

METHODS AND ANALYSIS

PubMed, the Cochrane library and Embase will be searched from inception to December 2019 for relevant randomised controlled trials (RCTs) that examined anti-diabetic drugs for diabetes prevention in patients with pre-diabetes. Two reviewers working independently will screen titles, abstracts and full papers. Data extraction will also be completed by two independent authors. The primary outcome will be the incidence of T2DM in patients with pre-diabetes at baseline. Secondary outcomes will include the achievement of normoglycaemia, all-cause mortality, cardiovascular mortality and hypoglycaemic event. Pairwise meta-analysis and NMA will be conducted for each outcome using a frequentist random-effects model. Additionally, subgroup analyses will also be performed. The comparison-adjusted funnel plot will be used to assess publication bias. The overall quality of evidence will be rated with the Grading of Recommendations Assessment, Development and Evaluation framework. Data analysis will be conducted using Stata V.14.0.

ETHICS AND DISSEMINATION

Ethics approval is not required. We plan to submit the results of this study to a peer-review journal.

PROSPERO REGISTRATION NUMBER

CRD42019119157.

Lorcaserin for prevention and remission of type 2 diabetes mellitus in people with overweight or obesity: protocol for a systematic review and meta-analysis

INTRODUCTION

High body mass index (BMI) is associated with risk of diabetes. Lorcaserin is a selective 5-hydroxytryptamine 2C agonist which exerts robust benefits on long-term weight loss by suppressing appetite among adults with overweight or obesity. The magnitude of efficacy of lorcaserin for preventing and remitting type 2 diabetes mellitus (T2DM) among those people remains undefined. Therefore, we plan to conduct this systematic review and meta-analysis to aggregate data from all published studies with regard to the issue to acquire reliable evidence.

METHODS AND ANALYSIS

We will search various databases for relevant trials published up to June 2019. Randomised controlled trials investigating the efficacy of lorcaserin for preventing and remitting T2DM among overweight and obese population will be included. A standardised data form will be used to complete data search and extraction in duplicate. All discrepancies will be resolved by consensus. The primary outcome will be incidence of T2DM in patients with pre-diabetes. Secondary outcomes will include achievement of normoglycaemia in people with pre-diabetes, remission of hyperglycaemia in patients with diabetes, the proportion of patients with weight loss of at least 5% or 10% and hypoglycaemia incident. Data synthesis and statistical analysis will be performed for each outcome with Stata V.14.0.

ETHICS AND DISSEMINATION

Ethics approval is not required. Results of our study will be submitted to a peer-review journal.

PROSPERO REGISTRATION NUMBER

CRD42019119136.