Metformin pharmacogenomics: current status and future directions

Impact of SLC22A1 rs12208357 on therapeutic response to metformin in type 2 diabetes patients

Introduction

: Metformin, an oral hypoglycemic agent, is generally used as the first-line treatment in type 2 diabetes mellitus (T2DM) patients. The response to metformin varies between patients, and its mechanisms remain incompletely understood. Genetic variations in proteins involved in the pharmacodynamics and pharmacokinetics of metformin, like OCT1 transporter, are suspected to explain this difference. This study investigated the association of the response to metformin in T2DM patients with the presence of rs12208357 (R61C) variant in the SLC22A1 gene.

Materials and methods

We selected 100 patients who responded and 100 patients who did not respond to metformin monotherapy after 20 weeks according to their HbA1c level change. We investigated the effect of rs12208357 on the structure, function, and stability of OCT1 protein and its interaction with metformin by in silico tools. To determine the genotype of rs12208357 we used the ARMS-PCR technique.

Results

The in silico study indicated that rs12208357 probably changes OCT1 stability, function, interaction site, and binding energy to metformin in the extracellular domain. ARMS-PCR also showed the frequency of T and C alleles were significantly different between responders and non-responders (P-value = 0.014), also there is a significant difference in CC and CT/TT genotype frequency between responders and non-responders (P-value = 0.023).

Conclusion

Based on the in silico study and ARMS-PCR experiment results, the CC genotype has a better response to metformin therapy and the carrier of the T allele (CT and TT genotype) probably has complications in glycemic control by metformin.

Effects of genetic variants of organic cation transporters on metformin response in newly diagnosed patients with type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a chronic disease that affects millions of people worldwide. Metformin is the optimal initial therapy for patients with T2DM. Genetic factors play a vital role in metformin response, including variations in drug efficacy and potential side effects. To determine the effects of genetic variants of multidrug and toxin extrusion protein 2 (MATE2), ataxia telangiectasia mutated (ATM), and serine/threonine kinase 11 (STK11) genes on metformin response in a cohort of Saudi patients. This prospective observational study included 76 T2DM newly diagnosed Saudi patients treated with metformin monotherapy and 80 control individuals. Demographic data, lipid profiles, creatinine levels, and hemoglobin A1c (HbA1c) levels were collected before and after treatment. All participants were genotyped for 5 single-nucleotide polymorphisms (SNPs), including rs4621031, rs34399035, rs2301759, rs1800058, and rs11212617, using TaqMan R genotyping assays. This study included 156 subjects. The subjects' mean ± SD age was 50.4 ± 10.14 years. The difference in HbA1c levels in T2DM after treatment ranged from -1.20% to 8.8%, with a mean value of 0.927 ± 1.73%. In general, 73.7% of the patients with T2DM showed an adequate response to metformin (HbA1c < 7%). STK11 (rs2301759) significantly affects the response to metformin in T2DM patients. In the rs2301759 single-nucleotide polymorphisms, the prevalence of an adequate response to metformin was significantly higher among patients with C/C and T/C genotypes than among non-responders (P = .021). However, no statistically significant associations were observed for the other tested SNPs. Our study provides evidence of an association between STK11 (rs2301759) and response to metformin in Saudi patients with T2DM. The need for targeted studies on specific gene-drug associations is emphasized, and further studies with a larger population should be conducted.

The Effect of Genetic Variants of SLC22A2 (rs662301 and rs315978) on the response to Metformin in type 2 Saudi diabetic patients

PURPOSE

To investigate the allelic and genotypic frequencies of the two genetic variations, NC_000006.12: g.160275887C > T (rs662301) and NC_000006.12:g.160231826 T > C (rs315978), in the SLC22A2 gene among the Saudi population. The primary goal is to elucidate potential associations with these genetic variations and the response to metformin therapy over 6 months to enhance our knowledge of the genetic basis of Type 2 Diabetes Mellitus (T2DM) and its clinical management in the Saudi population.

MATERIALS/METHODS

76 newly diagnosed T2DM patients, aged 30 to 60, of both sexes and Saudi origin, were treated with metformin monotherapy. Blood samples were collected before and after 6 months of therapy,80 healthy individuals were included as controls. Genomic DNA was extracted. Genotyping of the SLC22A2 genetic variations was performed using TaqMan® SNP Genotyping Assays. Binary logistic regression was utilized to evaluate how certain clinical parameters influence T2DM concerning the presence of SLC22A2 gene variants.

RESULTS

Among these patients, 73.3 % were responders, and 26.7 % were non-responders. For these variants, no statistically significant differences in genotype or allele frequencies were observed between responders and non-responders (p = 0.375 and p = 0.384 for rs662301; p = 0.473 and p = 0.481 for rs315978, respectively). For the SLC22A2 variant rs662301, the C/C genotype was significantly associated with increased T2DM risk with age and elevated HbA1c levels. Similarly, rs315978 revealed higher T2DM susceptibility and HbA1c elevation in C/C genotype carriers, specifically with advancing age compared to individuals with C/T and T/T genotypes.

CONCLUSION

The study offers insights into the genetic landscape of T2DM in Saudi Arabia. Despite the absence of significant associations with treatment response, the study suggests potential age-specific associations, this highlights the complexity of the disease. This research underscores the necessity for expanded research, considering diverse populations and genetic factors, to develop personalized treatment approaches. This study serves as a foundation for future investigations into the Saudi population, recognizing the need for a larger sample size.

Metformin treatment of juvenile mice alters aging-related developmental and metabolic phenotypes in sex-dependent and sex-independent manners

Metformin has attracted increasing interest for its potential benefits in extending healthspan and longevity. This study examined the effects of early-life metformin treatment on the development and metabolism of C57BL/6 J (B6) mice, with metformin administered to juvenile mice from 15 to 56 days of age. Metformin treatment led to decreased body weight in both sexes (P < 0.05, t-test). At 9 weeks of age, mice were euthanized and organ weights were recorded. The relative weight of retroperitoneal fat was decreased in females, while relative weights of perigonadal and retroperitoneal fat were decreased, and relative liver weight was increased in males (P < 0.05, t-test). Glucose and insulin tolerance tests (GTT and ITT) were conducted at the age of 7 weeks. ANOVA revealed a significant impairment in insulin sensitivity by the treatment, and a significantly interactive effect on glucose tolerance between sex and treatment, underscoring a disparity in GTT between sexes in response to the treatment. Metformin treatment reduced circulating insulin levels in fasting and non-fasting conditions for male mice, with no significant alterations observed in female mice. qRT-PCR analysis of glucose metabolism-related genes (Akt2, Glut2, Glut4, Irs1, Nrip1, Pi3k, Pi3kca, Pkca) in the liver and skeletal muscle reveals metformin-induced sex- and organ-specific effects on gene expression. Comparison with previous studies in heterogeneous UM-HET3 mice receiving the same treatment suggests that genetic differences may contribute to variability in the effects of metformin treatment on development and metabolism. These findings indicate that early-life metformin treatment affects development and metabolism in both sex- and genetics-dependent manners.

Pharmacogenetics of sodium-glucose co-transporter-2 inhibitors: Validation of a sex-agnostic pharmacodynamic biomarker

AIM

To validate pharmacodynamic responses to sodium-glucose co-transporter-2 (SGLT2) inhibitors and test for association with genetic variants in SLC5A4, SLC5A9, and SLC2A9.

METHODS

Canagliflozin (300 mg), a SGLT2 inhibitor, was administered to 30 healthy volunteers. Several endpoints were measured to assess clinically relevant responses, including drug-induced increases in urinary excretion of glucose, sodium and uric acid.

RESULTS

This pilot study confirmed that canagliflozin (300 mg) triggered acute changes in mean levels of several biomarkers: fasting plasma glucose (-4.1 mg/dL; P = 6 × 10-5 ), serum creatinine (+0.05 mg/dL; P = 8 × 10-4 ) and serum uric acid (-0.90 mg/dL; P = 5 × 10-10 ). The effects of sex on glucosuria depended upon how data were normalized. Whereas males' responses were ~60% greater when data were normalized to body surface area, males and females exhibited similar responses when glucosuria was expressed as grams of urinary glucose per gram-creatinine. The magnitude of glucosuria was not significantly correlated with fasting plasma glucose, estimated glomerular filtration rate or age in those healthy individuals without diabetes with an estimated glomerular filtration rate of more than 60 mL/min/1.73m2 .

CONCLUSIONS

Normalizing data relative to creatinine excretion will facilitate including data from males and females in a single analysis. Furthermore, because our ongoing pharmacogenomic study (NCT02891954) is conducted in healthy individuals, this will facilitate detection of genetic associations with limited confounding by other factors such as HbA1c and renal function.

Association of SLC22A1, SLC47A1, and KCNJ11 polymorphisms with efficacy and safety of metformin and sulfonylurea combination therapy in Egyptian patients with type 2 diabetes

Background and purpose

Multidrug and toxin extrusion transporter 1 (MATE1), encoded by the SLC47A1 gene and single nucleotide polymorphisms of organic cation transport 1, may impact metformin's responsiveness and side effects. Inward-rectifier potassium channel 6.2 (Kir 6.2) subunits encoded by KCNJ11 may affect the response to sulfonylurea. This study aimed to evaluate the association between SLC22A1 rs72552763 and rs628031, SLC47A1 rs2289669 and KCNJ11 rs5219 genetic variations with sulfonylurea and metformin combination therapy efficacy and safety in Egyptian type 2 diabetes mellitus patients.

Experimental approach

This study was conducted on 100 cases taking at least one year of sulfonylurea and metformin combination therapy. Patients were genotyped via the polymerase chain reaction-restriction fragment length polymorphism technique. Then, according to their glycated hemoglobin level, cases were subdivided into non-responders or responders. Depending on metformin-induced gastrointestinal tract side effects incidence, patients are classified as tolerant or intolerant.

Findings/Results

KCNJ11 rs5219 heterozygous and homozygous mutant genotypes, SLC47A1 rs2289669 heterozygous and homozygous mutant genotypes (AA and AG), and mutant alleles of both polymorphisms were significantly related with increased response to combined therapy. Individuals with the SLC22A1 (rs72552763) GAT/del genotype and the SLC22A1 (rs628031) AG and AA genotypes were at a higher risk for metformin-induced gastrointestinal tract adverse effects.

Conclusion and implications

The results implied a role for SLC47A1 rs2289669 and KCNJ11 rs5219 in the responsiveness to combined therapy. SLC22A1 (rs628031) and (rs72552763) polymorphisms may be associated with increased metformin adverse effects in type 2 diabetes mellitus patients.

Aging, oxidative stress and degenerative diseases: mechanisms, complications and emerging therapeutic strategies

Aging accompanied by several age-related complications, is a multifaceted inevitable biological progression involving various genetic, environmental, and lifestyle factors. The major factor in this process is oxidative stress, caused by an abundance of reactive oxygen species (ROS) generated in the mitochondria and endoplasmic reticulum (ER). ROS and RNS pose a threat by disrupting signaling mechanisms and causing oxidative damage to cellular components. This oxidative stress affects both the ER and mitochondria, causing proteopathies (abnormal protein aggregation), initiation of unfolded protein response, mitochondrial dysfunction, abnormal cellular senescence, ultimately leading to inflammaging (chronic inflammation associated with aging) and, in rare cases, metastasis. RONS during oxidative stress dysregulate multiple metabolic pathways like NF-κB, MAPK, Nrf-2/Keap-1/ARE and PI3K/Akt which may lead to inappropriate cell death through apoptosis and necrosis. Inflammaging contributes to the development of inflammatory and degenerative diseases such as neurodegenerative diseases, diabetes, cardiovascular disease, chronic kidney disease, and retinopathy. The body's antioxidant systems, sirtuins, autophagy, apoptosis, and biogenesis play a role in maintaining homeostasis, but they have limitations and cannot achieve an ideal state of balance. Certain interventions, such as calorie restriction, intermittent fasting, dietary habits, and regular exercise, have shown beneficial effects in counteracting the aging process. In addition, interventions like senotherapy (targeting senescent cells) and sirtuin-activating compounds (STACs) enhance autophagy and apoptosis for efficient removal of damaged oxidative products and organelles. Further, STACs enhance biogenesis for the regeneration of required organelles to maintain homeostasis. This review article explores the various aspects of oxidative damage, the associated complications, and potential strategies to mitigate these effects.

Acute pharmacodynamic responses to exenatide: Drug-induced increases in insulin secretion and glucose effectiveness

AIM

Glucagon-like peptide-1 receptor agonists provide multiple benefits to patients with type 2 diabetes, including improved glycaemic control, weight loss and decreased risk of major adverse cardiovascular events. Because drug responses vary among individuals, we initiated investigations to identify genetic variants associated with the magnitude of drug responses.

METHODS

Exenatide (5 μg, subcutaneously) or saline (0.2 ml, subcutaneously) was administered to 62 healthy volunteers. Frequently sampled intravenous glucose tolerance tests were conducted to assess the impact of exenatide on insulin secretion and insulin action. This pilot study was a crossover design in which participants received exenatide and saline in random order.

RESULTS

Exenatide increased first phase insulin secretion 1.9-fold (p = 1.9 × 10-9 ) and accelerated the rate of glucose disappearance 2.4-fold (p = 2 × 10-10 ). Minimal model analysis showed that exenatide increased glucose effectiveness (Sg ) by 32% (p = .0008) but did not significantly affect insulin sensitivity (Si ). The exenatide-induced increase in insulin secretion made the largest contribution to interindividual variation in exenatide-induced acceleration of glucose disappearance while interindividual variation in the drug effect on Sg contributed to a lesser extent (β = 0.58 or 0.27, respectively).

CONCLUSIONS

This pilot study provides validation for the value of a frequently sampled intravenous glucose tolerance test (including minimal model analysis) to provide primary data for our ongoing pharmacogenomic study of pharmacodynamic effects of semaglutide (NCT05071898). Three endpoints provide quantitative assessments of the effects of glucagon-like peptide-1 receptor agonists on glucose metabolism: first phase insulin secretion, glucose disappearance rates and glucose effectiveness.

Effect of Human Adenovirus 36 on Response to Metformin Monotherapy in Obese Mexican Patients with Type 2 Diabetes: A Prospective Cohort Study

Human adenovirus 36 (HAdV-36) has been associated with obesity and changes in glucose and lipid metabolism. The virus has been reported to increase insulin sensitivity and paradoxically promote weight gain. Because of its effects on metabolism, infection with the virus could alter the response to several drugs used to treat type 2 diabetes (DM2), such as metformin. The aim of this study was to test whether HAdV-36 affects the response to metformin in a group of obese patients with DM2.

METHODS

In a prospective cohort study, 103 obese patients with newly diagnosed DM2 were divided into two groups based on their HAdV-36 seropositivity (+HAdV-36 and -HAdV-36). Weight, glucose, cholesterol, triglycerides, body mass index, body fat percentage, and waist and hip circumference were measured and compared in both groups at baseline and after 45 days of metformin treatment.

RESULTS

Only glucose was significantly lower in the +HAdV-36 group at baseline, while all other variables were similar between the two study groups. After 45 days of follow-up, it was observed that the effect of metformin did not differ between the groups, but the variables improved significantly after treatment.

CONCLUSIONS

In this study, we did not find that HAdV-36 had an effect on the response to metformin in obese patients with DM2.

Pharmacogenetics of SGLT2 Inhibitors: Validation of a sex-agnostic pharmacodynamic biomarker

Aim

SGLT2 inhibitors provide multiple benefits to patients with type 2 diabetes - including improved glycemic control and decreased risks of cardiorenal disease. Because drug responses vary among individuals, we initiated investigations to identify genetic variants associated with the magnitude of drug responses.

Methods

Canagliflozin (300 mg) was administered to 30 healthy volunteers. Several endpoints were measured to assess clinically relevant responses - including drug-induced increases in urinary excretion of glucose, sodium, and uric acid.

Results

This pilot study confirmed that canagliflozin (300 mg) triggered acute changes in mean levels of several biomarkers: fasting plasma glucose (-4.1 mg/dL; p=6x10), serum creatinine (+0.05 mg/dL; p=8×10 -4 ), and serum uric acid (-0.90 mg/dL; p=5×10 -10 ). The effects of sex on glucosuria depended upon how data were normalized. Whereas males' responses were ∼60% greater when data were normalized to body surface area, males and females exhibited similar responses when glucosuria was expressed as grams of urinary glucose per gram-creatinine. The magnitude of glucosuria was not significantly correlated with fasting plasma glucose, estimated GFR, or age in these healthy non-diabetic individuals with estimated GFR>60 mL/min/1.73m 2 .

Conclusions

Normalizing data relative to creatinine excretion will facilitate including data from males and females in a single analysis. Furthermore, because our ongoing pharmacogenomic study ( NCT02891954 ) is conducted in healthy individuals, this will facilitate detection of genetic associations with limited confounding by other factors such as age and renal function.

Registration

NCT02462421 ( clinicaltrials.gov ).

Funding

Research grants from the National Institute of Diabetes and Digestive and Kidney Diseases: R21DK105401, R01DK108942, T32DK098107, and P30DK072488.

Acute pharmacodynamic responses to exenatide: Drug-induced increases in insulin secretion and glucose effectiveness

Background

GLP1R agonists provide multiple benefits to patients with type 2 diabetes - including improved glycemic control, weight loss, and decreased risk of major adverse cardiovascular events. Because drug responses vary among individuals, we initiated investigations to identify genetic variants associated with the magnitude of drug responses.

Methods

Exenatide (5 µg, sc) or saline (0.2 mL, sc) was administered to 62 healthy volunteers. Frequently sampled intravenous glucose tolerance tests were conducted to assess the impact of exenatide on insulin secretion and insulin action. This pilot study was designed as a crossover study in which participants received exenatide and saline in random order.

Results

Exenatide increased first phase insulin secretion 1.9-fold (p=1.9×10 -9 ) and accelerated the rate of glucose disappearance 2.4-fold (p=2×10 -10 ). Minimal model analysis demonstrated that exenatide increased glucose effectiveness (S g ) by 32% (p=0.0008) but did not significantly affect insulin sensitivity (S i ). The exenatide-induced increase in insulin secretion made the largest contribution to inter-individual variation in exenatide-induced acceleration of glucose disappearance while inter-individual variation in the drug effect on S g contributed to a lesser extent (β=0.58 or 0.27, respectively).

Conclusions

This pilot study provides validation for the value of an FSIGT (including minimal model analysis) to provide primary data for our ongoing pharmacogenomic study of pharmacodynamic effects of semaglutide ( NCT05071898 ). Three endpoints provide quantitative assessments of GLP1R agonists' effects on glucose metabolism: first phase insulin secretion, glucose disappearance rates, and glucose effectiveness.

Registration

NCT02462421 (clinicaltrials.gov).

Funding

American Diabetes Association (1-16-ICTS-112); National Institute of Diabetes and Digestive and Kidney Disease (R01DK130238, T32DK098107, P30DK072488).

Metformin for Prevention of Anthropometric and Metabolic Complications of Androgen Deprivation Therapy in Prostate Cancer Patients Receiving Radical Radiotherapy: A Phase II Randomized Controlled Trial

BACKGROUND

Patients with prostate cancer undergoing treatment with radical radiation therapy (RT) plus androgen deprivation therapy (ADT) experience a constellation of deleterious metabolic and anthropometric changes related to hypogonadism that are associated with increased morbidity and mortality. We assessed the effect of metformin versus placebo to blunt the adverse effects of ADT on body weight, waist circumference, and other metabolic parameters.

METHODS AND MATERIALS

This phase 2, multicenter, randomized controlled trial (RCT) randomized normoglycemic men with locally advanced prostate cancer receiving radical RT and ADT (18-36 months) in a 1:1 ratio to receive metformin 500 mg by mouth 3 times a day (for 30-36 months) versus identical placebo.

RESULTS

From December 2015 to October 2019, 83 men were randomized with median follow-up of 23 months. Baseline mean body mass Index (BMI) of the cohort was 30.2 (range 22.2-52.5). Change in mean weight relative to baseline was lower among men who received metformin compared with placebo at 5 months (-1.80 kg, P = .038), but was not significant with longer follow-up (1 year: +0.16 kg, P = .874). Although participants on ADT had increases in waist circumference in both study arms, metformin did not significantly reduce these changes (1 year: +2.79 cm (placebo) versus +1.46 cm (metformin), P = .336). Low-density lipoprotein (LDL) cholesterol was lower in the metformin arm (-0.32 mmol/L) compared with the placebo arm (-0.03 mmol/L) at 5 months (P = .022), but these differences were not significant with longer follow-up (1 year: -0.17 mmol/L vs -0.19 mmol/L, P = .896). There were no differences in HbA1C, triglyceride, high-density lipoprotein (HDL) cholesterol, and total cholesterol by study arm.

CONCLUSIONS

Men receiving radical RT and ADT gained weight and had increases in waist circumference over time that metformin did not significantly mitigate. Although this study did not observe any preventive effect of metformin on the anthropometric and metabolic complications of ADT, metformin continues to be studied in phase 3 RCTs in this patient population to assess its potential antineoplastic effects.

A Review of the Impact of Pharmacogenetics and Metabolomics on the Efficacy of Metformin in Type 2 Diabetes

Metformin is the most often prescribed drug for people with type 2 diabetes (T2D). More than 120 million patients with T2D use metformin worldwide. However, monotherapy fails to achieve glycemic control in a third of the treated patients. Genetics contribute to some of the inter-individual variations in glycemic response to metformin. Numerous pharmacogenetic studies have demonstrated that variations in genes related to pharmacokinetics and pharmacodynamics of metformin's encoding transporters are mainly associated with metformin response. The goal of this review is to evaluate the current state of metformin pharmacogenetics and metabolomics research, discuss the clinical and scientific issues that need to be resolved in order to increase our knowledge of patient response variability to metformin, and how to improve patient outcomes. Metformin's hydrophilic nature and absorption as well as its action mechanism and effectiveness on T2D initiation are discussed. The impacts of variations associated with various genes are analysed to identify and evaluate the effect of genetic polymorphisms on the therapeutic activity of metformin. The metabolic pattern of T2D and metformin is also indicated. This is to emphasise that studies of pharmacogenetics and metabolomics could expand our knowledge of metformin response in T2D.

Implications of genetic variations, differential gene expression, and allele-specific expression on metformin response in drug-naïve type 2 diabetes

PURPOSE

Metformin is widely used to treat type 2 diabetes mellitus (T2DM) individuals. Clinically, inter-individual variability of metformin response is of significant concern and is under interrogation. In this study, a targeted exome and whole transcriptome analysis were performed to identify predictive biomarkers of metformin response in drug-naïve T2DM individuals.

METHODS

The study followed a prospective study design. Drug-naïve T2DM individuals (n = 192) and controls (n = 223) were enrolled. T2DM individuals were administered with metformin monotherapy and defined as responders and non-responders based on their glycated haemoglobin change over three months. 146 T2DM individuals were used for the final analysis and remaining samples were lost during the follow-up. Target exome sequencing and RNA-seq was performed to analyze genetic and transcriptome profile. The selected SNPs were validated by genotyping and allele specific gene expression using the TaqMan assay. The gene prioritization, enrichment analysis, drug-gene interactions, disease-gene association, and correlation analysis were performed using various tools and databases.

RESULTS

rs1050152 and rs272893 in SLC22A4 were associated with improved response to metformin. The copy number loss was observed in PPARGC1A in the non-responders. The expression analysis highlighted potential differentially expressed targets for predicting metformin response (n = 35) and T2DM (n = 14). The expression of GDF15, TWISTNB, and RPL36A genes showed a maximum correlation with the change in HbA1c levels. The disease-gene association analysis highlighted MAGI2 rs113805659 to be linked with T2DM.

CONCLUSION

The results provide evidence for the genetic variations, perturbed transcriptome, allele-specific gene expression, and pathways associated with metformin drug response in T2DM.

Towards Precritical Medical Therapy of the Abdominal Aortic Aneurysm

Pharmacotherapy for abdominal aortic aneurysm (AAA) can be useful for prevention, especially in people at higher risk, for slowing down AAA progression, as well as for post-surgery adjuvant treatment. Our review focuses on novel pharmacotherapy approaches targeted towards slowing down progression of AAA, known also as secondary prevention therapy. Guidelines for AAA are not specific to slow down the expansion rate of an abdominal aortic aneurysm, and therefore no medical therapy is recommended. New ideas are urgently needed to develop a novel medical therapy. We are hopeful that in the future, pharmacologic treatment will play a key role in the prevention and treatment of AAA.

Metformin attenuates osteoarthritis by targeting chondrocytes, synovial macrophages and adipocytes

OBJECTIVE

To investigate the therapeutic effect and mechanism of metformin on knee osteoarthritis (OA) in normal diet (ND) mice or high-fat diet (HFD)-induced obese mice.

METHODS

Destabilization of the medial meniscus surgery was performed in ND mice or HFD mice, and metformin was administrated in drinking water or not. The changes of OA joint structure, infiltration and polarization of synovial macrophages and circulating and local levels of leptin and adiponectin were evaluated. In vitro, the effects of metformin on chondrocytes and macrophages, and of conditioned mediums derived from mouse abdominal fat on murine chondrogenic cell line ATDC5 and murine macrophage cell line RAW264.7, were detected.

RESULTS

Metformin showed protective effects on OA, characterized by reductions on OARSI score (2.00, 95% CI [1.15-2.86] for ND mice and 3.17, 95% CI [2.37-3.96] for HFD mice) and synovitis score (1.17, 95% CI [0.27-2.06] for ND mice and 2.50, 95% CI [1.49-3.51] for HFD mice) after 10 weeks of treatment, and the effects were more significant in HFD mice than in ND mice. Mechanistically, in addition to decreasing apoptosis and matrix-degrading enzymes expression in chondrocytes as well as infiltration and pro-inflammatory differentiation of synovial macrophages, metformin reduced leptin secretion by adipose tissue in HFD mice.

CONCLUSIONS

Metformin protects against knee OA which could be through reducing apoptosis and catabolism of chondrocytes, and suppressing infiltration and pro-inflammatory polarization of synovial macrophages. For obese mice, metformin has a greater protective effect in knee OA additionally through reducing leptin secretion from adipose tissue.

Variants of SLC2A10 may be Linked to Poor Response to Metformin

Purpose

A study among Filipinos revealed that only 15% of patients with diabetes achieved glycemic control, and poor response to metformin could be one of the possible reasons. Recent studies demonstrate how genetic variations influence response to metformin. Hence, the present study aimed to determine genetic variants associated with poor response to metformin.

Methods

Using a candidate variant approach, 195 adult Filipino participants with newly diagnosed type 2 diabetes mellitus (T2DM) were enrolled in a case-control study. Genomic DNA from blood samples were collected. Allelic and genotypic associations of variants with poor response to metformin were determined using exact statistical methods.

Results

Several polymorphisms were nominally associated with poor response to metformin (P_uncorr < 0.05). The most notable is the association of multiple variants in the SLC2A10 gene—rs2425911, rs3092412, and rs2425904—with common additive genetic mode of inheritance. Other variants that have possible associations with poor drug response include rs340874 (PROX-AS1), rs815815 (CALM2), rs1333049 (CDKN2B-AS1), rs2010963 (VEGFA), rs1535435 and rs9494266 (AHI1), rs11128347 (PDZRN3), rs1805081 (NPC1), and rs13266634 (SLC30A8).

Conclusion

In Filipinos, a trend for the association for several variants was noted, with further observation that several mechanisms may be involved. The results may serve as pilot data for further validation of candidate variants for T2DM pharmacotherapy.

Analysis of missense SNPs in the SLC47A1 and SLC47A2 genes affecting the pharmacokinetics of metformin: Computational approach

Background

Metformin as an anti-hyperglycaemic drug is commonly used for the treatment of type 2 diabetes mellitus (T2DM). The metformin response is variable due to the interindividual variation of pharmacokinetics which is based on strong genetic background. MATE1 and MATE2 proteins are significantly implicated in the pharmacokinetics of metformin. Missense SNPs with high risk of pathogenicity are expected to affect response to metformin via pharmacokinetics. Therefore, the aim of the current study is to determine the effects of missense SNPs in the SLC47A1 and SLC47A2 genes. The structural and functional consequences of all known SLC47A1 and SLC47A2 missense SNPs of the human MATE1 and MATE2 proteins were identified by various bioinformatics methods (SIFT, PhD-SNP, PolyPhen-2, PROVEAN, PMut, MUpro, I-Mutant 3.0, COACH, RaptorX Binding, ConSurf, STRING).

Results

The SLC47A1 variants P186T, L116P and the SLC47A2 variants I158N, L112P, V118G exhibited ΔΔG values less than − 1 kcal/mol, and these variants are considered to disrupt the structure and function of MATE1 and MATE2 proteins. SLC47A1 R118Q and SLC47A2 Y273C, V118G may significantly disturb protein function and transporting activities according to the analysis of ligand-binding regions.

Conclusion

It is suggested that high-risk deleterious missense SNPs may mediate the pharmacokinetics of metformin and may be associated with altered tissue distribution, renal clearance and metformin toxicity. We suppose that our results might serve as potential targets for the studies composed of the development of potential diagnostic and therapeutic strategies based on the relationship between mutations and metformin response.

Association of gene polymorphisms with body weight changes in prediabetic patients

BACKGROUND

Recent research has demonstrated that Type 2 Diabetes (T2D) risk is influenced by a number of common polymorphisms, including MC4R rs17782313, PPARG rs1801282, and TCF7L2 rs7903146. Knowledge of the association between these single nucleotide polymorphisms (SNPs) and body weight changes in different forms of prediabetes treatment is still limited. The aim of this study was to investigate the association of polymorphisms within the MC4R, PPARG, and TCF7L2 genes on the risk of carbohydrate metabolism disorders and body composition changes in overweight or obese patients with early carbohydrate metabolism disorders.

METHODS AND RESULTS

From 327 patients, a subgroup of 81 prediabetic female patients (48.7 ± 14.8 years) of Eastern European descent participated in a 3-month study comprised of diet therapy or diet therapy accompanied with metformin treatment. Bioelectrical impedance analysis and genotyping of MC4R rs17782313, PPARG rs1801282, and TCF7L2 rs7903146 polymorphisms were performed. The MC4R CC and TCF7L2 TT genotypes were associated with increased risk of T2D (OR = 1.46, p = 0.05 and OR = 2.47, p = 0.006, respectively). PPARG CC homozygotes experienced increased weight loss; however, no additional improvements were experienced with the addition of metformin. MC4R TT homozygotes who took metformin alongside dietary intervention experienced increased weight loss and reductions in fat mass (p < 0.05).

CONCLUSIONS

We have shown that the obesity-protective alleles (MC4R T and PPARG C) were positively associated with weight loss efficiency. Furthermore, we confirmed the previous association of the MC4R C and TCF7L2 T alleles with T2D risk.

Watermelon (Citrullus lanatus) leaf extract attenuates biochemical and histological parameters in high-fat diet/streptozotocin-induced diabetic rats

The present research aimed to investigate the attenuative effects of watermelon (Citrullus lanatus) leaf extract on biochemical and histological parameters in a high-fat diet combined with a low-dose streptozotocin (HFD/STZ)-induced type 2 diabetes mellitus. Forty male Sprague Dawley rats were divided into five groups, including three supplemented groups: 10 mg metformin/kg BW (HFD/STZ +M), 200 mg watermelon leaf extract /kg BW (HFD/STZ + LD), and 400 mg watermelon leaf extract /kg BW (HFD/STZ + HD). The efficacy of the 6-week intervention was evaluated by measuring body weight, fasting blood sugar, serum insulin, lipid profile, superoxide dismutase, catalase, malondialdehyde, and serum liver markers. Kidneys and liver structure were defined by histopathological examination. Results revealed that intervention with watermelon leaf extract attenuated the biochemical parameters and the structural changes in kidneys and liver. In brief, the watermelon leaf extract treatment could effectively decrease complications associated with diabetes better than metformin, and that the treatment with 400 mg/kg BW is the most potent. PRACTICAL APPLICATIONS: This was the first study to investigate the antidiabetic potential of watermelon leaf extract in obese diabetic rats. Data revealed that the watermelon leaf extract significantly attenuated the HFD/STZ-induced diabetes changes, as evidenced by the biochemical and histological data. Hence, watermelon leaf could be an excellent candidate to be developed as a functional food ingredients or nutraceuticals for holistic management of diabetes mellitus and its complications.

Phytomodulatory proteins isolated from Calotropis procera latex promote glycemic control by improving hepatic mitochondrial function in HepG2 cells

The medicinal uses of Calotropis procera are diverse, yet some of them are based on effects that still lack scientific support. Control of diabetes is one of them. Recently, latex proteins from C. procera latex (LP) have been shown to promote in vivo glycemic control by the inhibition of hepatic glucose production via AMP-activated protein kinase (AMPK). Glycemic control has been attributed to an isolated fraction of LP (CpPII), which is composed of cysteine peptidases (95%) and osmotin (5%) isoforms. Those proteins are extensively characterized in terms of chemistry, biochemistry and structural aspects. Furthermore, we evaluated some aspects of the mitochondrial function and cellular mechanisms involved in CpPII activity. The effect of CpPII on glycemic control was evaluated in fasting mice by glycemic curve and glucose and pyruvate tolerance tests. HepG2 cells was treated with CpPII, and cell viability, oxygen consumption, PPAR activity, production of lactate and reactive oxygen species, mitochondrial density and protein and gene expression were analyzed. CpPII reduced fasting glycemia, improved glucose tolerance and inhibited hepatic glucose production in control animals. Additionally, CpPII increased the consumption of ATP-linked oxygen and mitochondrial uncoupling, reduced lactate concentration, increased protein expression of mitochondrial complexes I, III and V, and activity of peroxisome-proliferator-responsive elements (PPRE), reduced the presence of reactive oxygen species (ROS) and increased mitochondrial density in HepG2 cells by activation of AMPK/PPAR. Our findings strongly support the medicinal use of the plant and suggest that CpPII is a potential therapy for prevention and/or treatment of type-2 diabetes. A common epitope sequence shared among the proteases and osmotin is possibly the responsible for the beneficial effects of CpPII.

Transporters, TBC1D4, and ARID5B Variants to Explain Glycated Hemoglobin Variability in Patients with Type 2 Diabetes

INTRODUCTION

Genetic variants could aid in predicting antidiabetic drug response by associating them with markers of glucose control, such as glycated hemoglobin (HbA1c). However, pharmacogenetic implementation for antidiabetics is still under development, as the list of actionable markers is being populated and validated. This study explores potential associations between genetic variants and plasma levels of HbA1c in 100 patients under treatment with metformin.

METHODS

HbA1c was measured in a clinical chemistry analyzer (Roche), genotyping was performed in an Illumina-GSA array and data were analyzed using PLINK. Association and prediction models were developed using R and a 10-fold cross-validation approach.

RESULTS

We identified genetic variants on SLC47A1, SLC28A1, ABCG2, TBC1D4, and ARID5B that can explain up to 55% of the interindividual variability of HbA1c plasma levels in diabetic patients under treatment. Variants on SLC47A1, SLC28A1, and ABCG2 likely impact the pharmacokinetics (PK) of metformin, while the role of the two latter can be related to insulin resistance and regulation of adipogenesis.

CONCLUSIONS

Our results confirm previous genetic associations and point to previously unassociated gene variants for metformin PK and glucose control.

The genetic association of the transcription factor NPAT with glycemic response to metformin involves regulation of fuel selection

The biguanide, metformin, is the first-choice therapeutic agent for type-2 diabetes, although the mechanisms that underpin metformin clinical efficacy remain the subject of much debate, partly due to the considerable variation in patient response to metformin. Identification of poor responders by genotype could avoid unnecessary treatment and provide clues to the underlying mechanism of action. GWAS identified SNPs associated with metformin treatment success at a locus containing the NPAT (nuclear protein, ataxia-telangiectasia locus) and ATM (ataxia-telangiectasia mutated) genes. This implies that gene sequence dictates a subsequent biological function to influence metformin action. Hence, we modified expression of NPAT in immortalized cell lines, primary mouse hepatocytes and mouse tissues, and analysed the outcomes on metformin action using confocal microscopy, immunoblotting and immunocytochemistry. In addition, we characterised the metabolic phenotype of npat heterozygous knockout mice and established the metformin response following development of insulin resistance. NPAT protein was localised in the nucleus at discrete loci in several cell types, but over-expression or depletion of NPAT in immortalised cell models did not change cellular responses to biguanides. In contrast, metformin regulation of respiratory exchange ratio (RER) was completely lost in animals lacking one allele of npat. There was also a reduction in metformin correction of impaired glucose tolerance, however no other metabolic abnormalities, or response to metformin, were found in the npat heterozygous mice. In summary, we provide methodological advancements for the detection of NPAT, demonstrate that minor reductions in NPAT mRNA levels (20–40%) influence metformin regulation of RER, and propose that the association between NPAT SNPs and metformin response observed in GWAS, could be due to loss of metformin modification of cellular fuel usage.

Metformin has no impact on nitric oxide production in patients with pre-diabetes

AIMS/INTRODUCTION

The authors evaluated the impact of different dose of metformin on NO (nitric oxide) production in subjects with pre-diabetes.

MATERIALS AND METHODS

The metformin-naïve patients from one Diabetic Center with newly diagnosed pre-diabetes, without cardio-vascular diseases, were randomized (based on the identification number, individual for each inhabitant in the country) for treatment with different doses of metformin (group A 3 × 500 mg, group B 3 × 1000 mg) for 12 weeks. Then, the subjects from group B were switched to dose 3 × 500 for the last 3 weeks. The wide panel of L-arginine/NO pathway metabolites concentrations was assessed using the liquid chromatography-mass spectrometry technique.

RESULTS

Between October 2017 and December 2018, 36 individuals were initially randomized to intervention groups. The study was completed with 25 subjects: 14 patients in group A, 11 in group B; also 11 healthy volunteers were recruited. There was no difference between participants with pre-diabetes and healthy volunteers as regards the baseline characteristics except for fasting glucose and fatty liver. The decrease of L-citrulline concentration only was reported for treatment groups during the intervention period, with no change for the other NO-production related substances.

CONCLUSION

It was the first study on the in vivo release of NO in humans with different metformin doses in patients with pre-diabetes. Metformin did not seem to increase NO production measured by the citrulline plasma levels, irrespective of the dose. The citrulline concentration change might indicate the drug impact on the condition of the enterocytes.

Pharmacological treatment of hyperglycemia in type 2 diabetes

Diabetes mellitus is a major public health problem, affecting about 10% of the population. Pharmacotherapy aims to protect against microvascular complications, including blindness, end-stage kidney disease, and amputations. Landmark clinical trials have demonstrated that intensive glycemic control slows progression of microvascular complications (retinopathy, nephropathy, and neuropathy). Long-term follow-up has demonstrated that intensive glycemic control also decreases risk of macrovascular disease, albeit rigorous evidence of macrovascular benefit did not emerge for over a decade. The US FDA's recent requirement for dedicated cardiovascular outcome trials ushered in a golden age for understanding the clinical profiles of new type 2 diabetes drugs. Some clinical trials with sodium-glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide 1 (GLP1) receptor agonists reported data demonstrating cardiovascular benefit (decreased risk of major adverse cardiovascular events and hospitalization for heart failure) and slower progression of diabetic kidney disease. This Review discusses current guidelines for use of the 12 classes of drugs approved to promote glycemic control in patients with type 2 diabetes. The Review also anticipates future developments with potential to improve the standard of care: availability of generic dipeptidylpeptidase-4 (DPP4) inhibitors and SGLT2 inhibitors; precision medicine to identify the best drugs for individual patients; and new therapies to protect against chronic complications of diabetes.

Pharmacokinetics of metformin in collagen-induced arthritis rats

Due to the elevated presence of cytokines, the expressions of metabolic enzymes and drug transporters are altered in rheumatoid arthritis (RA). Given the high incidence of diabetes in patients with RA, the aim of the present study was to investigate the metformin pharmacokinetics of a single oral dose in rats with collagen-induced arthritis (CIA). Blood and urine samples were collected at different timepoints, and analyzed by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Tissue samples were also collected to investigate the expression of metabolic enzymes and drug transporters by quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and western blot. The results indicated that the bioavailability of metformin was markedly decreased in the CIA rats. Moreover, metformin was not metabolized by enzymes of rat liver microsomes, suggesting that the decreased bioavailability of metformin was independent of the liver metabolism. In addition, the mRNA, protein expression level and activity of the renal organic cation transporter 2 (OCT2) was markedly increased, suggesting that the enhanced renal clearance of metformin in CIA rats may be due to the up-regulated activity of OCT2. In conclusion, our study suggested that the reduced bioavailability of metformin in CIA rats is possibly related to the up-regulated function of the renal protein OCT2.

Oral Antidiabetics and Sleep Among Type 2 Diabetes Patients: Data From the UK Biobank

Previous small-scale studies have found that oral antidiabetic therapy is associated with sleep difficulties among patients with type 2 diabetes (T2D). Here, we used data from 11 806 T2D patients from the UK Biobank baseline investigation to examine the association of oral antidiabetic therapy with self-reported difficulty falling and staying asleep and daily sleep duration. As shown by logistic regression adjusted for, e.g., age, T2D duration, and HbA_1c, patients on non-metformin therapy (N=815; 86% were treated with sulphonylureas) had a 1.24-fold higher odds ratio of reporting regular difficulty falling and staying asleep at night compared to those without antidiabetic medication use (N=5 366, P<0.05) or those on metformin monotherapy (N=5 625, P<0.05). Non-metformin patients reported about 8 to 10 minutes longer daily sleep duration than the other groups (P<0.05). We did not find significant differences in sleep outcomes between untreated and metformin patients. Our findings suggest that non-metformin therapy may result in sleep initiation and maintenance difficulties, accompanied by a small but significant sleep extension. The results of the present study must be replicated in future studies using objective measures of sleep duration and validated questionnaires for insomnia. Considering that most T2D patients utilize multiple therapies to manage their glycemic control in the long term, it may also be worth investigating possible interactions of antidiabetic drugs on sleep.

Population pharmacokinetics and dosing optimization of metformin in Chinese patients with type 2 diabetes mellitus

Approximately 35% of patients fail to attain ideal initial blood glucose control under metformin monotherapy. The objective of this observational study is to simulate the optimal protocol of metformin according to the different renal function.The population pharmacokinetics of metformin was performed in 125 subjects with type 2 diabetes mellitus. Plasma concentrations of metformin were quantified by high-performance liquid chromatography. A population pharmacokinetic model of metformin was developed using NONMEN (version 7.2, Icon Development Solutions, USA). Monte Carlo simulation was used to simulate the concentration-time profiles for doses of metformin for 1000 times at different stages of renal function.The mean population pharmacokinetic parameters were apparent clearance 53.0 L/h, apparent volume of distribution 438 L, absorption rate constant 1.4 hour and lag-time 0.91 hour. Covariate analyses revealed that estimated glomerular filtration rate (eGFR) and bodyweight as individual factors influencing the apparent oral clearance: CL/F = 53.0 × ( bodyweight/75) × (eGFR/102.5)EXP(0.1797). The results of the simulation showed that patients should be prescribed metformin 2550 mg/d (t.i.d.) vs 3000 mg/d (b.i.d.) as the minimum doses for patients with augmented renal clearance.eGFR had a significant impact on metformin pharmacokinetics. Patients administered metformin twice a day require higher total daily doses than those with a regimen of 3 times a day at each stage of kidney function.

Metformin and Chemoprevention: Potential for Heart-Healthy Targeting of Biologically Aggressive Breast Cancer

Currently, tamoxifen is the only drug approved for reduction of breast cancer risk in premenopausal women. The significant cardiovascular side effects of tamoxifen, coupled with lack of a survival benefit, potential for genotoxicity, and failure to provide a significant risk-reduction for estrogen receptor-negative breast cancer, all contribute to the low acceptance of tamoxifen chemoprevention in premenopausal women at high-risk for breast cancer. While other prevention options exist for postmenopausal women, there is a search for well-tolerated prevention agents that can simultaneously reduce risk of breast cancers, cardiovascular disease, and type-2 diabetes. Metformin is a well-tolerated oral biguanide hypoglycemic agent that is prescribed worldwide to over 120 million individuals with type-2 diabetes. Metformin is inexpensive, safe during pregnancy, and the combination of metformin, healthy lifestyle, and exercise has been shown to be effective in preventing diabetes. There is a growing awareness that prevention drugs and interventions should make the “whole woman healthy.” To this end, current efforts have focused on finding low toxicity alternatives, particularly repurposed drugs for chemoprevention of breast cancer, including metformin. Metformin's mechanisms of actions are complex but clearly involve secondary lowering of circulating insulin. Signaling pathways activated by insulin also drive biologically aggressive breast cancer and predict poor survival in women with breast cancer. The mechanistic rationale for metformin chemoprevention is well-supported by the scientific literature. Metformin is cheap, safe during pregnancy, and has the potential to provide heart-healthy breast cancer prevention. On-going primary and secondary prevention trials will provide evidence whether metformin is effective in preventing breast cancer.

Immunomodulatory and Antiviral Activity of Metformin and Its Potential Implications in Treating Coronavirus Disease 2019 and Lung Injury

The pandemic of coronavirus disease 2019 (COVID-19), a disease which causes severe lung injury and multiple organ damage, presents an urgent need for new drugs. The case severity and fatality of COVID-19 are associated with excessive inflammation, namely, a cytokine storm. Metformin, a widely used drug to treat type 2 diabetes (T2D) mellitus and metabolic syndrome, has immunomodulatory activity that reduces the production of proinflammatory cytokines using macrophages and causes the formation of neutrophil extracellular traps (NETs). Metformin also inhibits the cytokine production of pathogenic Th1 and Th17 cells. Importantly, treatment with metformin alleviates various lung injuries in preclinical animal models. In addition, a recent proteomic study revealed that metformin has the potential to directly inhibit SARS-CoV-2 infection. Furthermore, retrospective clinical studies have revealed that metformin treatment reduces the mortality of T2D with COVID-19. Therefore, metformin has the potential to be repurposed to treat patients with COVID-19 at risk of developing severe illness. This review summarizes the immune pathogenesis of SARS-CoV-2 and addresses the effects of metformin on inhibiting cytokine storms and preventing SARS-CoV-2 infection, as well as its side effects.

Solute Carrier Transportome in Chemotherapy-Induced Adverse Drug Reactions

Members of the solute carrier (SLC) family of transporters are responsible for the cellular influx of a broad range of endogenous compounds and xenobiotics. These proteins are highly expressed in the gastrointestinal tract and eliminating organs such as the liver and kidney, and are considered to be of particular importance in governing drug absorption and elimination. Many of the same transporters are also expressed in a wide variety of organs targeted by clinically important anticancer drugs, directly affect cellular sensitivity to these agents, and indirectly influence treatment-related side effects. Furthermore, targeted intervention strategies involving the use of transport inhibitors have been recently developed, and have provided promising lead candidates for combinatorial therapies associated with decreased toxicity. Gaining a better understanding of the complex interplay between transporter-mediated on-target and off-target drug disposition will help guide the further development of these novel treatment strategies to prevent drug accumulation in toxicity-associated organs, and improve the safety of currently available treatment modalities. In this report, we provide an update on this rapidly emerging field with particular emphasis on anticancer drugs belonging to the classes of taxanes, platinum derivatives, nucleoside analogs, and anthracyclines.

Metformin strongly affects transcriptome of peripheral blood cells in healthy individuals

Metformin is a commonly used antihyperglycaemic agent for the treatment of type 2 diabetes mellitus. Nevertheless, the exact mechanisms of action, underlying the various therapeutic effects of metformin, remain elusive. The goal of this study was to evaluate the alterations in longitudinal whole-blood transcriptome profiles of healthy individuals after a one-week metformin intervention in order to identify the novel molecular targets and further prompt the discovery of predictive biomarkers of metformin response. Next generation sequencing-based transcriptome analysis revealed metformin-induced differential expression of genes involved in intestinal immune network for IgA production and cytokine-cytokine receptor interaction pathways. Significantly elevated faecal sIgA levels during administration of metformin, and its correlation with the expression of genes associated with immune response (CXCR4, HLA-DQA1, MAP3K14, TNFRSF21, CCL4, ACVR1B, PF4, EPOR, CXCL8) supports a novel hypothesis of strong association between metformin and intestinal immune system, and for the first time provide evidence for altered RNA expression as a contributing mechanism of metformin’s action. In addition to universal effects, 4 clusters of functionally related genes with a subject-specific differential expression were distinguished, including genes relevant to insulin production (HNF1B, HNF1A, HNF4A, GCK, INS, NEUROD1, PAX4, PDX1, ABCC8, KCNJ11) and cholesterol homeostasis (APOB, LDLR, PCSK9). This inter-individual variation of the metformin effect on the transcriptional regulation goes in line with well-known variability of the therapeutic response to the drug.

Common Variants in 22 Genes Regulate Response to Metformin Intervention in Children with Obesity: A Pharmacogenetic Study of a Randomized Controlled Trial

Metformin is a first-line oral antidiabetic agent that has shown additional effects in treating obesity and metabolic syndrome. Inter-individual variability in metformin response could be partially explained by the genetic component. Here, we aimed to test whether common genetic variants can predict the response to metformin intervention in obese children. The study was a multicenter and double-blind randomized controlled trial that was stratified according to sex and pubertal status in 160 children with obesity. Children were randomly assigned to receive either metformin (1g/d) or placebo for six months after meeting the defined inclusion criteria. We conducted a post hoc genotyping study in 124 individuals (59 placebo, 65 treated) comprising finally 231 genetic variants in candidate genes. We provide evidence for 28 common variants as promising pharmacogenetics regulators of metformin response in terms of a wide range of anthropometric and biochemical outcomes, including body mass index (BMI) Z-score, and glucose, lipid, and inflammatory traits. Although no association remained statistically significant after multiple-test correction, our findings support previously reported variants in metformin transporters or targets as well as identify novel and promising loci, such as the ADYC3 and the BDNF genes, with plausible biological relation to the metformin's action mechanism. Trial Registration: Registered on the European Clinical Trials Database (EudraCT, ID: 2010-023061-21) on 14 November 2011 (URL: https://www.clinicaltrialsregister.eu/ctr-search/trial/2010-023061-21/ES).

Targeting the TR4 nuclear receptor-mediated lncTASR/AXL signaling with tretinoin increases the sunitinib sensitivity to better suppress the RCC progression

Renal cell carcinoma (RCC) is one of the most lethal urological tumors. Using sunitinib to improve the survival has become the first-line therapy for metastatic RCC patients. However, the occurrence of sunitinib resistance in the clinical application has curtailed its efficacy. Here we found TR4 nuclear receptor might alter the sunitinib resistance to RCC via altering the TR4/lncTASR/AXL signaling. Mechanism dissection revealed that TR4 could modulate lncTASR (ENST00000600671.1) expression via transcriptional regulation, which might then increase AXL protein expression via enhancing the stability of AXL mRNA to increase the sunitinib resistance in RCC. Human clinical surveys also linked the expression of TR4, lncTASR, and AXL to the RCC survival, and results from multiple RCC cell lines revealed that targeting this newly identified TR4-mediated signaling with small molecules, including tretinoin, metformin, or TR4-shRNAs, all led to increase the sunitinib sensitivity to better suppress the RCC progression, and our preclinical study using the in vivo mouse model further proved tretinoin had a better synergistic effect to increase sunitinib sensitivity to suppress RCC progression. Future successful clinical trials may help in the development of a novel therapy to better suppress the RCC progression.

Clinical and genetic predictors of diabetes drug's response

Diabetes is a major health problem worldwide. Glycemic control is the main goal in the management of type 2 diabetes. While many anti-diabetic drugs and guidelines are available, almost half of diabetic patients do not reach their treatment goal and develop complications. The glucose-lowering response to anti-diabetic drug differs significantly between individuals. Relatively little is known about the factors that might underlie this response. The identification of predictors of response to anti-diabetic drugs is essential for treatment personalization. Unfortunately, the evidence on predictors of drugs response in type 2 diabetes is scarce. Only a few trials were designed for specific groups of patients (e.g. patients with renal impairment or older patients), while subgroup analyses of larger trials are frequently unreported. Physicians need help in picking the drug which provides the maximal benefit, with minimal side effects, in the right dose, for a specific patient, using an omics-based approach besides the phenotypic characteristics.

Protective effect of metformin on a rat model of lipopolysaccharide-induced preeclampsia

Recent in vitro and clinical studies have found that metformin (MET) may play a preventive or therapeutic role in preeclampsia (PE) and may be a candidate drug for the prevention and/or treatment of PE. In this study, we used lipopolysaccharide (LPS) to induce a PE-like rat model and investigated the intervention effect of MET from the perspectives of clinical manifestations, placental morphology, serum marker for placental injury, systemic inflammatory response and oxidative/nitrative stress, and placental nuclear factor-κB (NF-κB) signaling. The results showed that MET improved LPS-induced hypertension, proteinuria, fetal growth restriction (FGR) and stillbirth, alleviated placental injury and decreased maternal serum marker alpha-fetoprotein (MS-AFP) level; MET suppressed LPS-induced TNF-α and IL-6 productions, reduced oxidative/nitrative stress as evidenced by increased superoxide dismutase (SOD) activity, decreased inducible nitric oxide synthase (iNOS) activity, and decreased levels of malondialdehyde (MDA) and nitric oxide (NO); MET inhibited LPS-induced NF-κB activation in placentas. Based on these findings, it can be concluded that MET is beneficial to the PE-like rat model by protecting placentas from injury, suppressing systemic inflammatory response and oxidative/nitrative stress, and inhibiting placental NF-κB signaling pathway. MET is a promising drug for prevention and/or treatment of PE.

Pharmacogenetics of Metformin for Medication-Induced Weight Gain in Autism Spectrum Disorder

Objectives: We recently found that metformin attenuated weight gain due to mixed dopamine and serotonin receptor antagonists, commonly termed atypical antipsychotics, in children and adolescents with autism spectrum disorder (ASD). Previous studies have found that genetic variation predicts response to metformin in diabetes. In this study, we aimed to assess whether response to metformin for weight gain in this population is associated with variants in five genes previously implicated in metformin response in diabetes. Methods: Youth with ASD who experienced significant weight gain while taking mixed receptor antagonist medications were randomly assigned to metformin or placebo for 16 weeks, followed by open-label metformin treatment for 16 weeks. In the 53 participants with available DNA samples, we used a linear, mixed model analysis to assess response in the first 16 weeks of metformin treatment, whether in the randomized or open-label period, based upon genotypes at polymorphisms in five genes previously associated with metformin response in diabetes: ATM, SLC2A2, MATE1, MATE2, and OCT1. Results: In the primary analysis, both ATM and OCT1 showed significant effects of genotype on change in body mass index z-scores, the primary outcome measure, during the first 16 weeks of treatment with metformin. No other polymorphism showed a significant difference. Conclusion: As has been shown for metformin treatment in diabetes, genetic variation may predict response to metformin for weight gain in youth with ASD treated with mixed receptor antagonists. Further work is needed to replicate these findings and evaluate whether they can be used prospectively to improve outcomes.

The influence of SLC22A1 rs622342 and ABCC8 rs757110 genetic variants on the efficacy of metformin and glimepiride combination therapy in Egyptian patients with type 2 diabetes

Background: The incidence of Type 2 Diabetes Mellitus (T2DM) in Egypt is considered one of the highest in the world. Metformin and Sulfonylureas are usually prescribed together due to their efficacy and their relatively low cost. Organic cation transport 1, encoded by SLC22A1 gene, is the main transporter of metformin into hepatocytes, which is considered metformin site of action. Sulfonylureas enhance insulin release from pancreatic B-cells through binding to sulfonylurea receptor 1, encoded by ABCC8 gene. Single nucleotide polymorphisms in the SLC22A1 and ABCC8 genes might affect the response of each drug.

Aims: To investigate the influence of SLC22A1 rs622342 (A>C) and ABCC8 rs757110 (A>C) genetic variants on the efficacy of metformin and glimepiride combination therapy in Egyptian T2DM patients.

Methods: Observational cross-sectional study in which patients receiving metformin and glimepiride combination therapy for at least 6 months were included for genotyping and classified into either responders or non-responders, based on their HbA1C level.

Results: A total of 127 patients were included and genotyped. They were divided into 93 responders (HbA1C<7%) and 34 non-responders (HbA1C≥7%). Minor allele frequencies for rs622342 and rs757110 were 0.189 and 0.271, respectively. Only SLC22A1 rs622342 variant was found to be associated with the response of combination therapy, in which AA alleles carriers were 2.7-times more responsive to metformin than C allele carriers (Recessive model, odds ratio = 2.718, p = 0.025, 95% CI = 1.112–6.385).

Conclusion: Genotyping of rs622342 can be useful in predicting the response to metformin in combination therapy in Egyptian T2DM patients.

Regulation of Mitochondrial Biogenesis as a Way for Active Longevity: Interaction Between the Nrf2 and PGC-1α Signaling Pathways

Aging is a general degenerative process related to deterioration of cell functions in the entire organism. Mitochondria, which play a key role in energy homeostasis and metabolism of reactive oxygen species (ROS), require lifetime control and constant renewal. This explains recently peaked interest in the processes of mitochondrial biogenesis and mitophagy. The principal event of mitochondrial metabolism is regulation of mitochondrial DNA (mtDNA) transcription and translation, which is a complex coordinated process that involves at least two systems of transcription factors. It is commonly believed that its major regulatory proteins are PGC-1α and PGC-1β, which act as key factors connecting several regulator cascades involved in the control of mitochondrial metabolism. In recent years, the number of publications on the essential role of Nrf2/ARE signaling in the regulation of mitochondrial biogenesis has grown exponentially. Nrf2 is induced by various xenobiotics and oxidants that oxidize some Nrf2 negative regulators. Thus, ROS, in particular H₂O₂, were found to be strong Nrf2 activators. At present, there are two major concepts of mitochondrial biogenesis. Some authors suggest direct involvement of Nrf2 in the regulation of this process. Others believe that Nrf2 regulates expression of the antioxidant genes, while the major and only regulator of mitochondrial biogenesis is PGC-1α. Several studies have demonstrated the existence of the regulatory loop involving both PGC-1α and Nrf2. In this review, we summarized recent data on the Nrf2 role in mitochondrial biogenesis and its interaction with PGC-1α in the context of extending longevity.

Metformin protects bone mass in ultra-high-molecular-weight polyethylene particle-induced osteolysis by regulating osteocyte secretion

Metformin, an anti-hyperglycemic agent used for type 2 diabetes, has recently been found to have more effects apart from glucose regulation. We found that, in ultra-high-molecular-weight polyethylene particle-induced osteolysis mouse models, metformin had bone protect property and reduced the negative regulator of bone formation sclerostin (SOST) and Dickkopf-related protein 1 (DKK1), and increased osteoprotegerin (OPG) secretion and the ratio of OPG/Receptor Activator for Nuclear Factor-κB Ligand (RANKL). In vitro, we established a 3D co-culture system in which metformin affects osteoblasts and osteoclasts through mature osteocytes secretion. Metformin (50 μM) significantly decreased SOST and DKK1 mRNA expression, stimulating alkaline phosphatase activity and proliferation of osteoblast, and increased OPG secretion and the ratio of OPG/RANKL, inhibiting osteoclastogenesis. Moreover, the effect on OPG was reversed by adenosine 5'-monophosphate-activated protein kinase inhibitor, Compound C. Our finding suggests that metformin induces differentiation and mineralization of osteoblasts, while inhibits osteoclastogenesis via mature osteocytes secretion. Therefore, the drug might be beneficial for not only diabetes but also in other bone disorders by acting on mature osteocytes.

Metformin modifies disparity in hepatocellular carcinoma incidence in men with type 2 diabetes but without chronic liver diseases

Background

We assessed racial/ethnic disparity in hepatocellular carcinoma (HCC) incidence among men with type 2 diabetes (T2D) but without chronic liver diseases (CLD), and whether metformin use modified the disparity.

Methods

Study cohort: the nationwide Veterans Administration Health Care System electronic medical records among 40‐89 years old men with T2D; without CLD, cancer, cardiovascular or renal diseases previously; insulin and thiazolidinedione naive. Logistic regression analyses compared HCC incidence between race/ethnicity groups under no metformin use adjusted for covariates and inverse propensity score weights (IPSW) for race/ethnicity. The generalizability technique integrated with IPSW was incorporated to compare covariates adjusted odds ratios (aOR) of HCC associated with metformin use among race/ethnicity groups.

Results

Study cohort: N = 84 433; 79.47% non‐Hispanic white (NHW), 15.5% non‐Hispanic African American (NHAA), 5.03% Hispanics; 36.76% metformin users; follow‐up 6.10 ± 2.87 years; age 67.8 ± 9.8 years, HbA1c 6.57 ± 0.98%; 0.14% HCC cases. Under no metformin use, HCC incidence was lower for NHAA vs NHW (aOR = 0.60 [0.40‐0.92]), similar between NHW and Hispanics. Metformin was associated with reduced HCC risk: aOR = 0.57 (0.40‐0.81) for NHW; aOR = 0.35 (0.25‐0.47) for NHAA; aOR = 0.31 (0.22‐0.43) for Hispanics. Metformin dose >1000 mg/d was neutral for NHW; less effective for NHAA (P = 0.02); more effective for Hispanics (P = 0.002).

Conclusions

In men with T2D but without CLD nor metformin use, HCC incidence was lower for NHAA compared to NHW or Hispanics; similar between NHW and Hispanics. Metformin use reduced HCC risk and modified the race/ethnicity disparity.

Impact

Metformin's heterogeneous HCC prevention effect elucidates potential interventions to modify HCC disparity in patients with T2D.

Metformin Pharmacogenetics: Effects of SLC22A1, SLC22A2, and SLC22A3 Polymorphisms on Glycemic Control and HbA1c Levels

Type 2 diabetes mellitus (T2DM) constitutes a major portion of Jordan’s disease burden, and incidence rates are rising at a rapid rate. Due to variability in the drug’s response between ethnic groups, it is imperative that the pharmacogenetics of metformin be investigated in the Jordanian population. The objective of this study was to investigate the relationship between twenty-one single nucleotide polymorphisms (SNPs) in the SLC22A1, SLC22A2, and SLC22A3 genes and their effects on metformin pharmacogenetics in Jordanian patients diagnosed with type 2 diabetes mellitus. Blood samples were collected from 212 Jordanian diabetics who fulfilled the inclusion criteria, which were then used in SNP genotyping and determination of HbA1c levels. The rs12194182 SNP in the SLC22A3 gene was found to have a significant association (p < 0.05) with lower mean HbA1c levels, and this association more pronounced in patients with the CC genotype (i.e., p-value was significant before correcting for multiple testing). Moreover, the multinomial logistic regression analysis showed that SNP genotypes within the SLC22A1, SLC22A2, and SLC22A3 genes, body mass index (BMI) and age of diagnosis were significantly associated with glycemic control (p < 0.05). The results of this study can be used to predict response to metformin and other classes of T2DM drugs, making treatment more individualized and resulting in better clinical outcomes.

Mulberry leaf active components alleviate type 2 diabetes and its liver and kidney injury in db/db mice through insulin receptor and TGF-β/Smads signaling pathway

Mulberry leaf is one of the commonly used traditional Chinese medicines, has been shown to exert hypoglycemic effects against diabetes. The aim of this study is to investigate the effects and mechanism of mulberry leaf flavonoids (MF), polysaccharides (MP) and alkaloids (MA) on diabetic and its liver and kidney injury. The db/db mice was adopted and the results showed that the FBG (fasting blood glucose) of model group continued to increase and associated liver and kidney injury. After the intervention of MP and MA, the value of FBG exhibited the most obvious hypoglycemic effect. MF and MP have obvious improved effect on kidney injury, which reduced the content of mALB/Cre (microalbumin/creatinine) in urine and improved the tubular epithelial cells edematous and renal cystic epithelial thickening. While the MF and MA possessed a significant effect on liver damage, manifested in reducing the levels of ALT (alanine aminotransferase) and AST (aspartate aminotransferase) and pathological changes of liver on db/db mice. Through metabolomics analysis, 13 endogenous potential biomarkers were identified in serum. The three effective components of mulberry can regulate the 13 potential biomarkers and the corresponding metabolic pathway. Collectively, the components of mulberry leaf have clear hypoglycemic effect and protective effect on liver and kidney injury and the effects are related to insulin receptor and TGF-β/Smads signaling pathway.

Precision Diabetes Is Slowly Becoming a Reality

The concept of precision medicine is becoming increasingly popular. The use of big data, genomics and other "omics" like metabolomics, proteomics and transcriptomics could make the dream of personalised medicine become a reality in the near future. As far as polygenic forms of diabetes like type 2 and type 1 diabetes are concerned, interesting leads are emerging, but precision diabetes is still in its infancy. However, with regard to monogenic forms of diabetes like maturity-onset diabetes of the young and neonatal diabetes mellitus, rapid strides have been made and precision diabetes has already become part of the clinical tools used at advanced diabetes centres. In patients with some monogenic form of diabetes, if the appropriate gene defects are identified, insulin injections can be stopped and be replaced by oral sulphonylurea drugs. In the coming years, rapid advances can be expected in the field of precision diabetes, thereby making the control of diabetes more effective and hopefully leading to prevention of its complications and improvement of the quality of life of people afflicted with diabetes.

Is metformin still the most efficacious first-line oral hypoglycaemic drug in treating type 2 diabetes? A network meta-analysis of randomized controlled trials

OBJECTIVES

The objective of the study is to compare the efficacy of hypoglycaemic drugs for type 2 diabetes mellitus (T2DM) by network meta-analysis of randomized controlled trials (RCTs).

METHODS

We compared 11 major oral hypoglycaemic drugs under five categories evaluated by RCTs as drug monotherapy for the patients with T2DM, measuring glycosylated haemoglobin (%) or fasting plasma glucose (mmol L^-1 ) as outcomes. RCT quality was assessed with the Cochrane risk of bias tool. Network meta-analysis estimated the mean differences and 95% credible intervals. Subgroup and sensitivity analyses were performed to determine the results robustness. The Grading of Recommendation, Assessment, Development, and Evaluation evidence strength was assessed.

RESULTS

Seventy-five RCTs including 33,830 patients were identified. Their study quality was high. Regarding glycosylated haemoglobin, top three anti-diabetics were repaglinide (mean differences -1.39 [95% credible intervals -1.75 to -1.03]), gliclazide (-1.37 [-2.04 to -0.71]) and metformin (-1.13 [-1.37 to -0.90]), against placebo. Regarding fasting plasma glucose, top three anti-diabetics were repaglinide (-2.01 [-2.75 to -0.97]), metformin (-1.72 [-2.16 to -1.27]) and glipizide (-1.57 [-2.44 to -0.64]), against placebo. There was no difference between metformin and repaglinide. Subgroup and sensitivity analyses found the results to be robust. The evidence strength was moderate to high.

CONCLUSION

This meta-analysis showed that repaglinide and metformin would be the most efficacious oral drugs for first-line monotherapy of T2DM.

Metformin transporter pharmacogenomics: insights into drug disposition-where are we now?

INTRODUCTION

Metformin is recommended as first-line treatment for type 2 diabetes (T2D) by all major diabetes guidelines. With appropriate usage it is safe and effective overall, but its efficacy and tolerability show considerable variation between individuals. It is a substrate for several drug transporters and polymorphisms in these transporter genes have shown effects on metformin pharmacokinetics and pharmacodynamics. Areas covered: This article provides a review of the current status of the influence of transporter pharmacogenomics on metformin efficacy and tolerability. The transporter variants identified to have an important influence on the absorption, distribution, and elimination of metformin, particularly those in organic cation transporter 1 (OCT1, gene SLC22A1), are reviewed. Expert opinion: Candidate gene studies have shown that genetic variations in SLC22A1 and other drug transporters influence the pharmacokinetics, glycemic responses, and gastrointestinal intolerance to metformin, although results are somewhat discordant. Conversely, genome-wide association studies of metformin response have identified signals in the pharmacodynamic pathways rather than the transporters involved in metformin disposition. Currently, pharmacogenomic testing to predict metformin response and tolerability may not have a clinical role, but with additional data from larger studies and availability of safe and effective alternative antidiabetic agents, this is likely to change.

Epigenetic Control of Pancreatic Regeneration in Diabetes

Both type 1 and type 2 diabetes are conditions that are associated with the loss of insulin-producing β-cells within the pancreas. An active research therefore aims at regenerating these β-cells with the hope that they could restore euglycemia. The approaches classically used consist in mimicking embryonic development, making use of diverse cell sources or converting pre-existing pancreatic cells. Despite impressive progresses and promising successes, it appears that we still need to gain further insight into the molecular mechanisms underlying β-cell development. This becomes even more obvious with the emergence of a relatively new field of research, epigenetics. The current review therefore focuses on the latest advances in this field in the context of β-cell (neo-)genesis research.