Pharmacogenomic Studies of Current Antidiabetic Agents and Potential New Drug Targets for Precision Medicine of Diabetes

Glucagon kinetics assessed by mathematical modelling during oral glucose administration in people spanning from normal glucose tolerance to type 2 diabetes

Background/Objectives

Glucagon is important in the maintenance of glucose homeostasis, with also effects on lipids. In this study, we aimed to apply a recently developed model of glucagon kinetics to determine the sensitivity of glucagon variations (especially, glucagon inhibition) to insulin levels ("alpha-cell insulin sensitivity"), during oral glucose administration.

Subjects/Methods

We studied 50 participants (spanning from normal glucose tolerance to type 2 diabetes) undergoing frequently sampled 5-hr oral glucose tolerance test (OGTT). The alpha-cell insulin sensitivity and the glucagon kinetics were assessed by a mathematical model that we developed previously.

Results

The alpha-cell insulin sensitivity parameter (named SGLUCA; "GLUCA": "glucagon") was remarkably variable among participants (CV=221%). SGLUCA was found inversely correlated with the mean glycemic values, as well as with 2-hr glycemia of the OGTT. When stratifying participants into two groups (normal glucose tolerance, NGT, N=28, and impaired glucose regulation/type 2 diabetes, IGR_T2D, N=22), we found that SGLUCA was lower in the latter (1.50 ± 0.50·10-2 vs. 0.26 ± 0.14·10-2 ng·L-1 GLUCA/pmol·L-1 INS, in NGT and IGR_T2D, respectively, p=0.009; "INS": "insulin").

Conclusions

The alpha-cell insulin sensitivity is highly variable among subjects, and it is different in groups at different glucose tolerance. This may be relevant for defining personalized treatment schemes, in terms of dietary prescriptions but also for treatments with glucagon-related agents.

The effects of transcription factor 7-like 2 rs7903146 and paired box 4 rs2233580 variants associated with type 2 diabetes on the therapeutic efficacy of hypoglycemic agents

Aim

This study aims to investigate the effects of the TCF7L2 rs7903146 and PAX4 rs2233580 (R192H) variants associated with T2D on the therapeutic efficacies of various HAs in patients with T2D after follow-up for 3 years.

Methods

A total of 526 patients who were followed up at the Diabetic Clinic of Siriraj Hospital during 2016-2019 were enrolled. The variants TCF7L2 rs7903146 and PAX4 rs2233580 (R192H) were genotyped using the RNase H2 enzyme-based amplification (rhAmp) technique and the associations between genotypes and glycemic control after treatments with different combinations HA were evaluated using Generalized Estimating Equations (GEE) analysis.

Results

Patients who carried TCF7L2 rs7903146C/T + T/T genotypes when they were treated with biguanide alone had significantly lower fasting plasma glucose (FPG) than those of the patients who carried the C/C genotype (p = 0.01). Patients who carried the PAX4 rs2233580 G/G genotype when they were treated with sulfonylurea alone had significantly lower FPG than those of the patients who carried G/A + A/A genotypes (p = 0.04).

Conclusion

Genotypes of TCF7L2 rs7903146 and PAX4 rs2233580 (R192H) variants associated with T2D influence the therapeutic responses to biguanide and sulfonylurea. Different genotypes of these two variants might distinctively affect the therapeutic effects of HAs. This finding provides evidence of pharmacogenetics in the treatment of diabetes.

"Green" synthesized versus chemically synthesized zinc oxide nanoparticles: In vivo antihyperglycemic activity and pharmacokinetics

Zinc is one of the most studied trace elements, commonly used as supplement in diabetes treatment. By its involvement in the synthesis, secretion of insulin, promotion of insulin sensitivity and its multiple enzymatic functions it is known to contribute to reduce hyperglycemia. Researchers have shown that zinc administered under the form of zinc oxide nanoparticles (ZnONPs) is more effective than under its ionic form. Studies evaluating the antihyperglycemic activity of these nanocarriers include both ZnONPs synthesised using plants (i.e. green synthesized) or chemically synthesized. The present work aims to compare green synthesized ZnONPs with the marketed chemically synthesized ones. Green ZnONPs were synthesized using the aqueous extract of the stem bark of the medicinal plant Panda oleosa and zinc nitrate hexahydrate. Both nanocarriers were compared in terms of optical properties, morphology, composition, chemical functions, resistance to oxidation, in vivo antihyperglycemic activity via oral glucose tolerance test (OGTT) and pharmacokinetics in relation to zinc in C57BL/6J mice. A UV absorption peak was observed at 354 nm and 374 nm for the green and marketed ZnONPs, respectively. The shape and hydrodynamic diameters were anisotropic and of 228.8 ± 3.0 nm for the green ZnONPs and spherical and of 225.6 ± 0.9 nm for the marketed ZnONPs. Phenolic compounds accounted for 2.58 ± 0.04% of the green ZnONPs and allowed them to be more stable and unaffected by an oxidizing agent during the experiment, while the marketed chemically synthesized ZnONPs aggregated with or without contact with an oxidizing agent. No significant differences were observed on the amounts of zinc absorbed when comparing green ZnONPs, chemically synthesized ZnONPs and zinc sulfate in a pharmacokinetics study in normoglycemic mice. When evaluating the in vivo hypoglycemic activity of the nanocarriers in obese/diabetic mice, green synthesized ZnONPs displayed a significant hypoglycemic effect compared with the chemically synthesized nanoparticles following an OGTT. Altogether, these data indicate that phytocompounds, as catechin derivatives and polyphenols, attached to the green synthesized ZnONPs' surface, could contribute to their hypoglycemic activity. The comparison thus demonstrated that green synthesized ZnONPs are significantly more efficient than chemically ones at reducing hyperglycemia regardless of their absorption.

Recent Trends in the Antidiabetic Prominence of Natural and Synthetic Analogues of Aurones

Natural products are a boundless source for the development of pharmaceutical agents against a wide range of human diseases. Accordingly, naturally occurring aurones possess various biological benefits, such as anticancer, antioxidant, antimicrobial, antidiabetic, anti-inflammatory, antiviral and neuroprotective effects. In addition, various studies have revealed that aurones are potential templates for the regulation of diabetes mellitus and its associated complications. Likewise, certain aurones and their analogues have been found to be remarkable kinase inhibitors of DARK2, PPAR-γ, PTPM1, AGE, α-amylase and α-glucosidase, which represents a promising approach for the treatment of chronic metabolic disorders such as diabetes. Therefore, in our present study, we provide a detailed account of the advances in aurones as antidiabetic agents over the past decade.

Exploring the hidden treasures of Nitella hyalina: a comprehensive study on its biological compounds, nutritional profile, and unveiling its antimicrobial, antioxidative, and hypoglycemic properties

Macroalgae has the potential to be a precious resource in food, pharmaceutical, and nutraceutical industries. Therefore, the present study was carried out to identify and quantify the phyco-chemicals and to assess the nutritional profile, antimicrobial, antioxidant, and anti-diabetic properties of Nitella hyalina extracts. Nutritional composition revealed0.05 ± 2.40% ash content, followed by crude protein (24.66 ± 0.95%), crude fat (17.66 ± 1.42%), crude fiber (2.17 ± 0.91%), moisture content (15.46 ± 0.48%) and calculated energy value (173.50 ± 2.90 Kcal/100 g). 23 compounds were identified through GC-MS analysis in ethyl acetate extract, with primary compounds being Palmitic acid, methyl ester, (Z)-9-Hexadecenoic acid, methyl ester, and Methyl tetra decanoate. Whereas 15 compounds were identified in n-butanol extract, with the major compounds being Tetra decanoic acid, 9-hexadecanoic acid, Methyl pentopyranoside, and undecane. FT-IR spectroscopy confirmed the presence of alcoholic phenol, saturated aliphatic compounds, lipids, carboxylic acid, carbonyl, aromatic components, amine, alkyl halides, alkene, and halogen compounds. Moreover, n-butanol contains 1.663 ± 0.768 mg GAE/g, of total phenolic contents (TPC,) and 2.050 ± 0.143 QE/g of total flavonoid contents (TFC), followed by ethyl acetate extract, i.e. 1.043 ± 0.961 mg GAE/g and 1.730 ± 0.311 mg QE/g respectively. Anti-radical scavenging effect in a range of 34.55-46.35% and 35.39-41.79% was measured for n-butanol and ethyl acetate extracts, respectively. Antimicrobial results declared that n-butanol extract had the highest growth inhibitory effect, followed by ethyl acetate extract. Pseudomonas aeruginosa was reported to be the most susceptible strain, followed by Staphylococcus aureus and Escherichia coli, while Candida albicans showed the least inhibition at all concentrations. In-vivo hypoglycemic study revealed that both extracts exhibited dose-dependent activity. Significant hypoglycemic activity was observed at a dose of 300 mg/kg- 1 after 6 h i.e. 241.50 ± 2.88, followed by doses of 200 and 100 mg/kg- 1 (245.17 ± 3.43 and 250.67 ± 7.45, respectively) for n-butanol extract. In conclusion, the macroalgae demonstrated potency concerning antioxidant, antimicrobial, and hypoglycemic properties.

Profiling of patients with type 2 diabetes based on medication adherence data

Introduction

Type 2 diabetes mellitus (T2DM) is a complex, chronic disease affecting multiple organs with varying symptoms and comorbidities. Profiling patients helps identify those with unfavorable disease progression, allowing for tailored therapy and addressing special needs. This study aims to uncover different T2DM profiles based on medication intake records and laboratory measurements, with a focus on how individuals with diabetes move through disease phases.

Methods

We use medical records from databases of the last 20 years from the Department of Endocrinology and Diabetology of the University Medical Center in Maribor. Using the standard ATC medication classification system, we created a patient-specific drug profile, created using advanced natural language processing methods combined with data mining and hierarchical clustering.

Results

Our results show a well-structured profile distribution characterizing different age groups of individuals with diabetes. Interestingly, only two main profiles characterize the early 40-50 age group, and the same is true for the last 80+ age group. One of these profiles includes individuals with diabetes with very low use of various medications, while the other profile includes individuals with diabetes with much higher use. The number in both groups is reciprocal. Conversely, the middle-aged groups are characterized by several distinct profiles with a wide range of medications that are associated with the distinct concomitant complications of T2DM. It is intuitive that the number of profiles increases in the later age groups, but it is not obvious why it is reduced later in the 80+ age group. In this context, further studies are needed to evaluate the contributions of a range of factors, such as drug development, drug adoption, and the impact of mortality associated with all T2DM-related diseases, which characterize these middle-aged groups, particularly those aged 55-75.

Conclusion

Our approach aligns with existing studies and can be widely implemented without complex or expensive analyses. Treatment and drug use data are readily available in healthcare facilities worldwide, allowing for profiling insights into individuals with diabetes. Integrating data from other departments, such as cardiology and renal disease, may provide a more sophisticated understanding of T2DM patient profiles.

PMAT variant rs3889348 is associated with metformin-induced gastrointestinal among Chinese Type 2 diabetes patients

Aim: This study examined intronic gene variants for their association with metformin intolerance in a Chinese population, focusing on the plasma monoamine transporter (PMAT) cis-protein expression quantitative trait loci (cis-eQTL) variant rs3889348. Methods: We recruited Type 2 diabetes patients from two hospitals and identified 111 metformin-intolerant patients using a questionnaire, and selected 206 metformin-tolerant patients from 2180 Type 2 diabetes mellitus patients. Genetic testing revealed an association between adverse gastrointestinal (GI) effects and SLC22A1 and PMAT. Results: The single-nucleotide polymorphism rs3889348 is associated with metformin-induced adverse GI effects. Each additional copy of the G allele increases the score by 5.23 (95% CI: 1.82-8.64; p = 0.003). Patients taking more transporter inhibitors were more likely to respond to metformin-induced GI intolerance (p = 0.042). Conclusion: PMAT cis-eQTL rs3889348 was significantly associated with metformin-induced adverse GI effects.

Association of ABCC8 gene variants with response to sulfonylurea in type 2 diabetes mellitus

Background

Diabetes mellitus (DM) is associated with high blood glucose levels and sulfonylureas (SFUs) are one of the treatment options for DM. SFUs bind to sulfonylurea-1 receptor (SUR1), which is encoded by the ABCC8 gene and leads to blood glucose reduction. Genetic variants like rs757110 and rs1799854 of ABCC8 can influence the response to the drug's efficiency. Therefore, this study aimed to investigate the association between the ABCC8 rs757110 and rs1799854 genetic variants and response to SFUs treatment.

Methods

Totally, 61 DM patients with SFUs treatment were included. Baseline characteristics of the patients were recorded and 5 ml of blood was taken from each patient. After DNA extraction, a sequence containing rs757110 and rs1799854 was synthesized by the PCR method, and the PCR products were used for Sanger sequencing.

Results

Frequencies of GG, GA, and AA genotypes of rs1799854 variant was 12 (40%), 14 (46.7%), and 4 (13.3%), and the frequencies of CC, AC, and AA genotypes for rs757110 variant was 3 (9.7%), 5 (16.1%) and 23 (74.2%) in, respectively. Patients with different genotypes had the same age, BMI (body mass index), initial FBS (Fasting blood sugar), initial HbA1c, treatment duration, gender and history of smoking, alcohol consumption, and exercise. There was no significant difference in FBS and HbA1c changes after SFUs treatment between patients with rs757110 variant (p = 0.39 for FBS and p = 0.76 for HbA1c) and rs1799854 (p = 0.24 for FBS and p = 0.36 for HbA1c).

Conclusion

The rs1799854 and rs757110 variants of the ABCC8 gene had no significant influence on response to SFUs treatment.

Synthesis, in vitro inhibitor screening, structure-activity relationship, and molecular dynamic simulation studies of novel thioquinoline derivatives as potent α-glucosidase inhibitors

New series of thioquinoline structures bearing phenylacetamide 9a-p were designed, synthesized and the structure of all derivatives was confirmed using different spectroscopic techniques including FTIR, ¹H-NMR, ¹³C-NMR, ESI-MS and elemental analysis. Next, the α-glucosidase inhibitory activities of derivatives were also determined and all the synthesized compounds (IC₅₀ = 14.0 ± 0.6-373.85 ± 0.8 μM) were more potent than standard inhibitors acarbose (IC₅₀ = 752.0 ± 2.0 μM) against α-glucosidase. Structure-activity relationships (SARs) were rationalized by analyzing the substituents effects and it was shown that mostly, electron-donating groups at the R position are more favorable compared to the electron-withdrawing group. Kinetic studies of the most potent derivative, 9m, carrying 2,6-dimethylphenyl exhibited a competitive mode of inhibition with K_i value of 18.0 µM. Furthermore, based on the molecular dynamic studies, compound 9m depicted noticeable interactions with the α-glucosidase active site via several H-bound, hydrophobic and hydrophilic interactions. These interactions cause interfering catalytic potential which significantly decreased the α-glucosidase activity.

Genetic variants of the GLP-1R gene affect the susceptibility and glucose metabolism of gestational diabetes mellitus: a two-center nested case‒control study

BACKGROUND

Gestational diabetes mellitus (GDM) is the most common complication during pregnancy, occurring under the combined action of environmental and genetic factors. Genetic variants of glucagon-like peptide-1 receptor (GLP-1R) have been reported to affect insulin secretion and susceptibility to type 2 diabetes. This study aimed to explore the role of GLP-1R polymorphisms in GDM and glucose metabolism.

METHODS

A two-center nested case‒control study was designed, including 200 pregnant women with GDM and 200 pregnant women without GDM genotyped for five tag SNPs of GLP-1R using Sanger sequencing. Logistic regression was used to evaluate the relationship between GLP-1R polymorphisms and GDM risk. Glucose and insulin concentrations were measured based upon the 75 g oral glucose tolerance test (OGTT). Beta cell function of different genotypes was estimated with the 60 min insulinogenic index (IGI₆₀) and OGTT-derived disposition index (DI).

RESULTS

Mutant genotype AG + GG of tag SNP rs6458093 nominally increased GDM risk (p = 0.049), especially among subjects younger than 35 years (p = 0.024) and with BMI no less than 24 (p = 0.041), after adjusting for confounders. Meanwhile, compared with subjects with wild genotype AA, subjects with genotype AG + GG of rs6458093 also showed nominally significantly lower IGI₆₀ (p = 0.032) and DI (p = 0.029), as well as significantly higher 75 g OGTT-based 1 h glucose load plasma glucose levels (p = 0.045). Moreover, the mutant heterozygous genotype GA of tag SNP rs3765467 nominally decreased GDM risk among subjects older than 35 years (p = 0.037) but showed no association with insulin secretion and glucose homeostasis.

CONCLUSIONS

Tag SNP rs6458093 of GLP-1R was nominally associated with increased GDM risk and affected beta cell function and postprandial glucose metabolism, while tag SNP rs3765467 of GLP-1R was nominally associated with decreased GDM risk, providing evidence for molecular markers and etiological study of GDM.

Effects of the TCF7L2 and KCNQ1 common variant on sulfonylurea response in type 2 diabetes mellitus patients: a preliminary pharmacogenetic study

Background

Type 2 diabetes mellitus (T2DM) is a common chronic condition characterized by high blood glucose levels which is caused by genetic and environmental factors. Currently, pharmacogenomics (PGx) is anticipated to enable the development of personalized treatment in a wide range of health issues. Sulfonylureas (SFUs) are among the oral anti-diabetic drugs that are very popular due to their low cost. Genetic variants in transcription factor 7 like 2 (TCF7L2) and potassium voltage-gated channel subfamily Q member 1 (KCNQ1) have been reported for altered therapeutic response to sulfonylurea. The aim of the present study is to evaluate any association between common genetic variant of the TCF7L2 and KCNQ1 (rs7903146 and rs2237892, respectively) and the response to sulfonylurea in a group of Iranian patients for the first time.

Methods

Genotyping was carried out in 30 T2DM patients who received sulfonylurea treatment for more than two months in addition to previous medication using the Sanger sequencing method.

Results

In 30 T2DM patients who received SFUs treatment, 60%, 33.3% and 6.7% had CC, CT and TT genotypes, respectively. After treatment, adjusted fasting blood sugar (FBS) mean reduction level in CT and TT carriers was lower than CC carriers. Adjusted hemoglobin A1c (HbA1c) mean reduction level was also lower in CT and TT compared with CC carriers, but, none of these differences were statistically significant. Genotype frequencies of TT, CT and CC genotypes of rs2237892 variant of KCNQ1 gene were 0 (0%), 3 (10%) and 27 (90%) respectively. Patients with CT and CC genotypes of rs2237892 variant had also similar changes in FBS (P=0.200) and HbA1c (P=0.436) after treatment with SFUs.

Conclusions

Genotypes of TCF7L2 and KCNQ1 common variant did not show any impact on the treatment response among T2DM patients receiving SFUs.

GPR21 Inhibition Increases Glucose-Uptake in HepG2 Cells

GPR21 is a constitutively active, orphan, G-protein-coupled receptor, with in vivo studies suggesting its involvement in the modulation of insulin sensitivity. However, its precise contribution is not fully understood. As the liver is both a major target of insulin signalling and critically involved in glucose metabolism, the aim of this study was to examine the role of GPR21 in the regulation of glucose uptake and production in human hepatocytes. In particular, HepG2 cells, which express GPR21, were adopted as cellular models. Compared with untreated cells, a significant increase in glucose uptake was measured in cells treated with siRNA to downregulate GPR21 expression or with the GPR21-inverse agonist, GRA2. Consistently, a significantly higher membrane translocation of GLUT-2 was measured under these conditions. These effects were accompanied by an increased ratio of phAKT^(Ser473)/tot-AKT and phGSK-3β^(Ser9)/tot-GSK-3β, thus indicating a marked activation of the insulin signalling pathway. Moreover, a significant reduction in ERK activation was observed with GPR21 inhibition. Collectively, these results indicate that GPR21 mediates the negative effects on glucose uptake by the liver cells. In addition, they suggest that the pharmacological inhibition of GPR21 could be a novel strategy to improve glucose homeostasis and counteract hepatic insulin resistance.

Novel strategies for glycaemic control and preventing diabetic complications applying the clustering-based classification of adult-onset diabetes mellitus: A perspective

Diabetes mellitus results from an interplay between insulin resistance and β-cell dysfunction. Since their relative contributions to its pathogenesis are difficult to quantify, therapeutic strategies for glycaemic control are determined primarily based on two limited metrics: plasma glucose and haemoglobin A1c. Recent attempts have been made to subclassify diabetes mellitus to better predict its associated pathology and plan appropriate therapeutic strategies. These classifications are based on data-driven cluster analysis using autoimmunity, age, obesity (metabolically unhealthy and healthy phenotypes), insulin secretory capacity and resistance, and ethnicity. This review addresses potential therapeutic strategies for the cluster-based classifications of adult-onset diabetes mellitus to achieve better glycaemic control and prevent or at least delay the concomitant complications.

Advances in Pharmacotherapeutics, Metabolic Surgery, and Technology for Diabetes

Remarkable advances in diabetes management have occurred since the discovery of insulin 100 years ago. Advances across a therapeutic spectrum, including pharmacotherapy, metabolic surgery, and diabetes technology, offer superior treatment options for diabetes management. New medication classes (glucagon-like peptide-1 receptor analogs and SGLT-2 inhibitors) have demonstrated cardiorenal benefits beyond glycemic control in type 2 diabetes mellitus, while evolving metabolic surgical interventions also help patients achieve diabetes remission. The use of artificial pancreas systems has shown consistent improvement in glycemic control in type 1 diabetes mellitus. It is time for policy changes to expand access to such advantageous therapies.

Circulating microRNAs Signature for Predicting Response to GLP1-RA Therapy in Type 2 Diabetic Patients: A Pilot Study

Type 2 diabetes (T2D) represents one of the major health issues of this century. Despite the availability of an increasing number of anti-hyperglycemic drugs, a significant proportion of patients are inadequately controlled, thus highlighting the need for novel biomarkers to guide treatment selection. MicroRNAs (miRNAs) are small non-coding RNAs, proposed as useful diagnostic/prognostic markers. The aim of our study was to identify a miRNA signature occurring in responders to glucagon-like peptide 1 receptor agonists (GLP1-RA) therapy. We investigated the expression profile of eight T2D-associated circulating miRNAs in 26 prospectively evaluated diabetic patients in whom GLP1-RA was added to metformin. As expected, GLP1-RA treatment induced significant reductions of HbA1c and body weight, both after 6 and 12 months of therapy. Of note, baseline expression levels of the selected miRNAs revealed two distinct patient clusters: “high expressing” and “low expressing”. Interestingly, a significantly higher percentage of patients in the high expression group reached the glycemic target after 12 months of treatment. Our findings suggest that the evaluation of miRNA expression could be used to predict the likelihood of an early treatment response to GLP1-RA and to select patients in whom to start such treatment, paving the way to a personalized medicine approach.

The Impact of Glucose-Lowering Drugs on Sarcopenia in Type 2 Diabetes: Current Evidence and Underlying Mechanisms

The age-related decrease in skeletal muscle mass together with the loss of muscle power and function is defined sarcopenia. Mounting evidence suggests that the prevalence of sarcopenia is higher in patients with type 2 diabetes mellitus (T2DM), and different mechanisms may be responsible for this association such as impaired insulin sensitivity, chronic hyperglycemia, advanced glycosylation end products, subclinical inflammation, microvascular and macrovascular complications. Glucose-lowering drugs prescribed for patients with T2DM might impact on these mechanisms leading to harmful or beneficial effect on skeletal muscle. Importantly, beyond their glucose-lowering effects, glucose-lowering drugs may affect per se the equilibrium between protein anabolism and catabolism through several mechanisms involved in skeletal muscle physiology, contributing to sarcopenia. The aim of this narrative review is to provide an update on the effects of glucose-lowering drugs on sarcopenia in individuals with T2DM, focusing on the parameters used to define sarcopenia: muscle strength (evaluated by handgrip strength), muscle quantity/quality (evaluated by appendicular lean mass or skeletal muscle mass and their indexes), and physical performance (evaluated by gait speed or short physical performance battery). Furthermore, we also describe the plausible mechanisms by which glucose-lowering drugs may impact on sarcopenia.

Prominent and emerging anti-diabetic molecular targets

Diabetes is on the rise across the globe affecting more than 463 million people and crucially increasing morbidities of diabetes-associated diseases. Urgent and immense actions are needed to improve diabetes prevention and treatment. Regarding the correlation of diabetes with many associated diseases, inhibition of the disease progression is more crucial than controlling symptoms. Currently, anti-diabetic drugs are accompanied by undesirable side-effects and target confined types of biomolecules. Thus, extensive research is demanding to identify novel disease mechanisms and molecular targets as probable candidates for effective treatment of diabetes. This review discusses the conventional molecule targets that have been applied for their therapeutic rationale in treatment of diabetes. Further, the emerging and prospective molecular targets for the future focus of library screenings are presented.