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

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.

The Influence of OCT3 and MATE2 Genetic Polymorphisms in Poor Response to Metformin in Type 2 Diabetes Mellitus

BACKGROUND

The response of patients with Type 2 diabetes mellitus (T2DM) to metformin may be a variation because of genetic differences in solute carrier (SLC) transporter proteins and other effect factors, which have an important effect on how metformin is processed in the body and its efficiency for glycaemic control.

AIM

This study was conducted to investigate the impact of certain genetic variants of the organic cation transporter genes OCT3 (SLC22A3 rs12194182 and rs8187722) and MATE2 (SLC47A2 rs12943590) and their association with glycaemic parameters in patients with T2DM who respond poorly to metformin.

PATIENTS AND METHODS

This cross-sectional study involved 150 Iraqi cases with T2DM who were prescribed a daily dose of (1000 mg/day) metformin for a minimum of 3 months. Various parameters included are as follows: demographic data, glycaemic parameters and three SNPs: rs12943590 variant of SLC47A2, rs12194182 and rs8187722 variant of SLC22A3 using the standard PCR-sequencing technique.

RESULTS

Thirty-nine patients (26.17%) were responders, whereas 111 patients (73.82%) could not respond to metformin treatment. Upon analysing the genotypes of the rs12943590 variants of SLC47A2, rs12194182 and rs8187722 SNPs of SLC22A3, the present findings revealed a nonsignificant association of genetic variations in all SNPs with metformin response. SLC47A2 (rs12943590) showed nonsignificant associations of the GG, AA and AG genotyping; SLC22A3 (rs12194182) showed nonsignificant associations of the TT, TC and CC genotyping; and SLC22A3 (rs8187722) showed nonsignificant associations of the AA, CC and AC genotyping between two groups.

CONCLUSION

Variations in genes SLC22A3 and SLC47A2 did not have a significant role in the response of patients with T2DM to metformin (1000 mg/day).

Polycystic Ovary Syndrome Physiologic Pathways Implicated Through Clustering of Genetic Loci

CONTEXT

Polycystic ovary syndrome (PCOS) is a heterogeneous disorder, with disease loci identified from genome-wide association studies (GWAS) having largely unknown relationships to disease pathogenesis.

OBJECTIVE

This work aimed to group PCOS GWAS loci into genetic clusters associated with disease pathophysiology.

METHODS

Cluster analysis was performed for 60 PCOS-associated genetic variants and 49 traits using GWAS summary statistics. Cluster-specific PCOS partitioned polygenic scores (pPS) were generated and tested for association with clinical phenotypes in the Mass General Brigham Biobank (MGBB, N = 62 252). Associations with clinical outcomes (type 2 diabetes [T2D], coronary artery disease [CAD], and female reproductive traits) were assessed using both GWAS-based pPS (DIAMANTE, N = 898,130, CARDIOGRAM/UKBB, N = 547 261) and individual-level pPS in MGBB.

RESULTS

Four PCOS genetic clusters were identified with top loci indicated as following: (i) cluster 1/obesity/insulin resistance (FTO); (ii) cluster 2/hormonal/menstrual cycle changes (FSHB); (iii) cluster 3/blood markers/inflammation (ATXN2/SH2B3); (iv) cluster 4/metabolic changes (MAF, SLC38A11). Cluster pPS were associated with distinct clinical traits: Cluster 1 with increased body mass index (P = 6.6 × 10-29); cluster 2 with increased age of menarche (P = 1.5 × 10-4); cluster 3 with multiple decreased blood markers, including mean platelet volume (P = 3.1 ×10-5); and cluster 4 with increased alkaline phosphatase (P = .007). PCOS genetic clusters GWAS-pPSs were also associated with disease outcomes: cluster 1 pPS with increased T2D (odds ratio [OR] 1.07; P = 7.3 × 10-50), with replication in MGBB all participants (OR 1.09, P = 2.7 × 10-7) and females only (OR 1.11, 4.8 × 10-5).

CONCLUSION

Distinct genetic backgrounds in individuals with PCOS may underlie clinical heterogeneity and disease outcomes.

Influence of Solute Carrier Family 22 Member 1 (SLC22A1) Gene Polymorphism on Metformin Pharmacokinetics and HbA1c Levels: A Systematic Review

BACKGROUND

Solute Carrier Family 22 Member 1 (SLC22A1, also known as OCT1) protein has a vital role in the metabolism of metformin, a first-line anti-diabetes medication. Genetic poly-morphism in SLC22A1 influences individual response to metformin.

OBJECTIVE

This review aims to compile the current knowledge about the effects of SLC22A1 genetic polymorphism on metformin pharmacokinetics and HbA1c levels.

METHODS

We followed the PRISMA 2020 standards to conduct a systematic review. We searched the publications for all appropriate evidence on the effects of SLC22A1 genetic polymorphism on metformin pharmacokinetics and HbA1c from January 2002 to December 2022.

RESULTS

Initial database searches identified 7,171 relevant studies. We reviewed 155 titles and abstracts after deleting duplicates. After applying inclusion and exclusion criteria, 23 studies remained.

CONCLUSION

Three studies found that rs12208357, rs34059508, and G465R had a considerable impact (p < 0.05) on metformin pharmacokinetics, resulting in increased metformin plasma (Cmax), a higher active amount of drug in the blood (AUC), and lower volume of distribution (Vd) (p<0.05). SLC22A1 polymorphisms with effects on HbA1c include rs628031 (four of seven studies), rs622342 (four of six studies), rs594709 (one study), rs2297374, and rs1867351 (one of two studies), rs34130495 (one study), and rs11212617 (one study) (p < 0.05).

Association between organic cation transporter genetic polymorphisms and metformin response and intolerance in T2DM individuals: a systematic review and meta-analysis

Background

Variants in organic cation transporter (OCT) genes play a crucial role in metformin pharmacokinetics and are critical for diabetes treatment. However, studies investigating the effect of OCT genetic polymorphisms on metformin response have reported inconsistent results. This review and meta-analysis aimed to evaluate the associations between OCT genetic polymorphisms and metformin response and intolerance in individuals with type 2 diabetes mellitus (T2DM).

Method

A systematic search was conducted on PubMed, EMBASE, CNKI, WANFANG DATA, and VIP database for identifying potential studies up to 10 November 2022. The Q-Genie tool was used to evaluate the quality of included studies. Pooled odds ratios (OR) or standardized mean differences (SMD) and 95% confidence intervals (95% CI) were calculated to determine the associations between OCT genetic polymorphisms and metformin response and intolerance that were reflected by glycemic response indexes, such as glycated hemoglobin level (HbA1c%) or change in glycated hemoglobin level (ΔHbA1c%), fasting plasma level (FPG) or change in fasting plasma glucose level (ΔFPG), the effectiveness rate of metformin treatment, and the rate of metformin intolerance. A qualitative review was performed for the variants identified just in one study and those that could not undergo pooling analysis.

Results

A total of 30 related eligible studies about OCT genes (SLC22A1, SLC22A2, and SLC22A3) and metformin pharmacogenetics were identified, and 14, 3, and 6 single nucleotide polymorphisms (SNPs) in SLC22A1, SLC22A2, and SLC22A3, respectively, were investigated. Meta-analysis showed that the SLC22A1 rs622342 polymorphism was associated with a reduction in HbA1c level (AA vs. AC: SMD [95% CI] = -0.45 [-0.73--0.18]; p = 0.001). The GG genotype of the SLC22A1 rs628031 polymorphism was associated with a reduction in FPG level (GG vs. AA: SMD [95 %CI] = -0.60 [-1.04-0.16], p = 0.007; GG vs. AG: -0.45 [-0.67-0.20], p < 0.001). No statistical association was found between the remaining variants and metformin response and intolerance.

Conclusion

SLC22A1 rs622342 and rs628031 polymorphisms were potentially associated with glycemic response to metformin. This evidence may provide novel insight into gene-oriented personalized medicine for diabetes.

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.

Genetic polymorphism of organic cation transporter 2 (OCT2) and its effects on the pharmacokinetics and pharmacodynamics of Metformin: a narrative review

Background

Organic cation transporter 2 (OCT2) is a renal carrier transporter protein found in the basolateral membrane of proximal epithelial cells, which facilitates active secretion of Metformin. The genetic polymorphism of OCT2 influences the pharmacodynamic and pharmacokinetic effect of Metformin in type 2 diabetes mellitus (T2DM) patients. This is also mainly associated with frequencies of the associated risk allele in a particular population.

Objective

The purpose of the study is to determine the impact of OCT2 genetic polymorphism on Metformin pharmacodynamics (PD) and pharmacokinetics (PK).

Method of study

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for performing the research. Following databases were used to conduct the search: PubMed/MEDLINE, Google Scholar, and the Cochrane Library. Relevant studies were retrieved and literatures were appraised for methodology, demographic characteristics, relevant SNPs, genetic intervention trials, and outcomes.

Results

Based on the data collected, 13 OCT2 Single nucleotide polymorphisms (SNPs) were identified across various ethnic groups. There were significant differences between the frequency distribution of shared alleles and impact of thirteen SNPs on Metformin. Among the thirteen OCT2 variants studied, rs316019 variant produced the most diverse responses in population by showing positive and negative impact on PK & PD of Metformin.

Discussion and conclusion

Each population's OCT2 polymorphism had a distinct effect on Metformin responsiveness. The findings of this study could bring significant benefits to patients with OCT2 genetic polymorphism if individualised T2DM therapy is introduced. Patient-centered treatment would improve the Metformin efficacy leading to new research in personalised medicine.

Hydralazine Revives Cellular and Ocular Lens Health-Span by Ameliorating the Aging and Oxidative-Dependent Loss of the Nrf2-Activated Cellular Stress Response

A major hallmark of aging-associated diseases is the inability to evoke cellular defense responses. Transcriptional protein Nrf2 (nuclear factor erythroid-derived 2-related factor) plays a pivotal role in the oxidative stress response, cellular homeostasis, and health span. Nrf2's activation has been identified as a therapeutic target to restore antioxidant defense in aging. Here, we demonstrated that FDA-approved drug, hydralazine (Hyd), was a reactivator of the Nrf2/ARE (antioxidant response element) pathway in various ages and types of mouse (m) or human (h) lens epithelial cells (LECs) and mice lenses in-vitro/in-vivo. This led to Hyd-driven abatement of carbonyls, reduced reactive oxygen species (ROS), and reduced 4-HNE/MDA-adducts with cytoprotection, and extended lens healthspan by delaying/preventing lens opacity against aging/oxidative stress. We elucidated that Hyd activated the protective signaling by inducing Nrf2 to traverse from the cytoplasm to the nucleus and potentiated the ARE response by direct interaction of Nrf2 and ARE sequences of the promoter. Loss-of-function study and cotreatment of Hyd and antioxidant, N-acetyl cysteine (NAC) or Peroxiredoxin (Prdx)6, specified that Nrf2/ARE-driven increase in the promoter activity was Hyd-dependent. Our study provides proof-of concept evidence and, thereby, paves the way to repurposing Hyd as a therapeutic agent to delay/prevent aging and oxidative-related disorders.

Pharmacogenetics of Metformin Transporters Suggests No Association with Therapeutic Inefficacy among Diabetes Type 2 Mexican Patients

Mexico has been under official epidemiological alert due to diabetes since 2016. This study presents new information on the frequency and variants of metformin transporters OCT1, OCT2, OCT3, ABCB1, and CYP2C9 variants as well. It also reports the association with HbA1c control on 103 DMT2 patients. They were genotyped through real-time PCR (TaqMan assays) and grouped according to treatment: metformin and metformin + glibenclamide. Metformin plasmatic levels were determined through mass spectrometry. The analysis of HbA1c showed statistical significance across genotypes in polymorphisms rs72552763 (p = 0.022), rs622342 (p = 0.009), rs1128503 (p = 0.021), and rs2032582 (p = 0.009) within the monotherapy group. Bivariate analysis found no association between any polymorphism and HbA1c control. Two logistic regression models accounted for two diplotypes in OCT1 and ABCB1, including statistically significant covariates. The first model yielded significance in age (p = 0.026), treatment period [p = 0.001], BMI ≥ 25 kg/m2 (p = 0.043), and combined therapy (p < 0.001). There was no association with GAT/GAT of rs72552763 or A/A rs622342 in OCT1. The second model yielded significance in age (p = 0.017), treatment period (p = 0.001), BMI ≥ 25 kg/m2 (p = 0.042), and combined therapy (p < 0.001), finding no association with C/C of rs1128503 or G/G of rs2032582 in ABCB1. Our multinomial logistic regression results may benefit future predictive analyses in diabetic populations.

The influence of SLC22A3 rs543159 and rs1317652 genetic variants on metformin therapeutic efficacy in newly diagnosed patients with type 2 diabetes mellitus: 25 weeks follow-up study

BACKGROUND AND AIMS

Among anti-diabetic medications, metformin has been proven to be the preferred initial pharmacologic agent for type 2 diabetes mellitus (T2DM) treatment. Despite its safety and efficacy, the response to metformin varies between individuals. Genetic variations, especially within genes involved in pharmacokinetics and pharmacodynamics of metformin (e.g SLC22A3), have been suggested to be responsible for the observed inter-individual differences. By considering the undeniable role of organic cation transporter 3 in hepatic uptake of metformin, this study was aimed to investigate the association of rs543159 and rs1317652 variants in SLC22A3 gene with response to metformin monotherapy in newly diagnosed patients with T2DM.

METHODS

The study included 200 T2DM patients who received metformin monotherapy for 25 weeks. The patients were classified into 2 groups according to their HbA1c values: the responders (reduction in HbA1c levels by at least 1% after 25 weeks treatment with metformin) and non-responders (less than 1% reduction in HbA1c levels after 25 weeks treatment with metformin). We used tetra ARMS-PCR method to determine genotypes of the target variants.

RESULTS

For the rs543159, CA and AA genotypes were more frequent in responders as compared to non-responders (OR = 2.48; 95% CI = 1.28-4.78, P-value = 0.0057) under the dominant model. In case of rs1317652 CC and CT genotypes were more frequent in metformin responders as compared to non-responder group (OR = 2.49; 95% CI = 1.32-4.70, P-value = 0.0043) under the dominant model. Parameters such as fasting blood sugar (FBS), HbA1c, and total cholesterol (TC) levels were significantly lower in the responder group after 25 weeks of metformin monotherapy. Moreover, according to the result of multiple linear regression rs543159 and base line HbA1c values are significantly associated with response to metformin monotherapy.

CONCLUSION

Our results suggested that rs543159 and rs1317652 in SLC22A3 gene might be associated with variability in response to metformin therapy in T2DM patients.

A Metformin Pharmacogenetic Study of Patients with Type 2 Diabetes Mellitus and SLC22A1 Gene Mutation

Background: The purpose of this study was to determine the profiles of patients with type 2 diabetes (T2DM) and an SLC22A1 gene mutation in order to evaluate the effect of metformin pharmacogenetics. Methods: To assess the effect of pharmacogenetics, a mutation of the SLC22A1 gene in T2DM patients receiving metformin was investigated. Blood samples were taken from 50 diabetics of Minangkabau ethnicity who met the inclusion criteria, and SNP genotyping and blood glucose levels were determined. DNA is extracted and purified from blood samples using DNAzol® Genomic DNA Kits (Thermofischer Scientific) reagents. The Chi-square test and Independent sample T test were used to analyze the data. A statistically significant association was defined as a p-value < 0.05. Finally, the GraphPad Prism 7.00 program was used to gather and analyze data. Results: The adjusted odds ratio for inadequate fasting blood glucose was 1.48 (95% CI 1.18-1.95) in this study, while the adjusted odds ratio for diet discipline was 1.23 (95% CI 1.18-1.95). The adjusted odds ratio for low physical activity was 1.18. (95% CI 1.05-1.81). According to the sequencing data, the proportion of mutants is high at exon 2 rs683369 (G> C), while the percentage of wildtype and heterozygous mutants is the same at introns rs4646272 (T> G). Conclusion: Obesity, diet discipline, and low physical activity were all found to increase the likelihood of insufficient fasting blood glucose in T2DM patients. Exon 2 rs683369 (G> C) has a high proportion of mutants, but introns rs4646272 (T> G) have the same percentage of wildtype and heterozygous mutants.

Contribution of membrane transporters to chemotherapy-induced cardiotoxicity

Membrane transporters play a key role in determining the pharmacokinetic profile, therapeutic safety, and efficacy of many chemotherapeutic drugs by regulating cellular influx and efflux. Rapidly emerging evidence has shown that tissue-specific expression of transporters contributes to local drug accumulation and drug-drug interactions and that functional alterations in these transporters can directly influence an individual's susceptibility to drug-induced toxicity. Comprehending the complex mechanism of transporter function in regulating drug distribution in tissues, such as the heart, is necessary in order to acquire novel therapeutic strategies aimed at evading unwanted drug accumulation and toxicities and to ameliorate the safety of current therapeutic regimens. Here, we provide an overview of membrane transporters with a role in chemotherapy-induced cardiotoxicity and discuss novel strategies to improve therapeutic outcomes.

Genetic variants in SLC22A1 are related to serum lipid levels in Mexican women

Dyslipidemia is the main risk factor for coronary artery disease and is characterized by alterations in concentrations of lipids, including low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), and triacylglycerols. The participation of several genes in the development of dyslipidemia has been evidenced. Genetic variants in SLC22A1 have been associated with elevated cholesterol and LDL-c levels. The aim of this study was to evaluate the association between single-nucleotide polymorphisms (SNPs) in the SLC22A1 gene with atherogenic risk lipid levels in Mexican women. Anthropometric and biochemical measurements were performed, and four SNPs in SLC22A1 were genotyped by real-time polymerase chain reaction. The Hardy-Weinberg equilibrium was verified, and haplotype frequencies were calculated. We found significant differences between the allele frequencies of the SNPs analyzed with those reported in Mexico and in the world, which could be due to differences in the historical admixture of the women studied. Generalized linear models were evaluated to determine the association between genotypes and haplotypes with lipids levels. We identified a significant increase in total cholesterol and LDL-c levels in women who were carriers of the GA and AG genotypes of the polymorphisms rs628031 and rs594709, respectively, significant effect that is also shown in a dominant inheritance model. Interestingly, we identified an important relationship of the AGC-GAT haplotype with the elevation in LDL-c levels and AGA-GAT haplotype with the elevation in HDL-c levels. On the other hand, we found a strong linkage disequilibrium between the polymorphisms studied. Our results show that variants in the SLC22A1 gene influence serum levels of atherogenic risk lipids, suggesting that these variants probably affect the function of organic cation transporter-1 and therefore, on the regulation of lipid metabolism.

Pharmacogenomics and Personalized Medicine in Type 2 Diabetes Mellitus: Potential Implications for Clinical Practice

Type 2 diabetes mellitus (T2DM) is the most common form of diabetes, and is rising in incidence with widespread prevalence. Multiple gene variants are associated with glucose homeostasis, complex T2DM pathogenesis, and its complications. Exploring more effective therapeutic strategies for patients with diabetes is crucial. Pharmacogenomics has made precision medicine possible by allowing for individualized drug therapy based on a patient's genetic and genomic information. T2DM is treated with various classes of oral hypoglycemic agents, such as biguanides, sulfonylureas, thiazolidinediones, meglitinides, DPP4 inhibitors, SGLT2 inhibitors, α-glucosidase inhibitors, and GLP1 analogues, which exhibit various pharmacogenetic variants. Although genomic interventions in monogenic diabetes have been implemented in clinical practice, they are still in the early stages for complex polygenic disorders, such as T2DM. Precision DM medicine has the potential to be effective in personalized therapy for those suffering from various forms of DM, such as T2DM. With recent developments in genetic techniques, the application of candidate-gene studies, large-scale genotyping investigations, genome-wide association studies, and "multiomics" studies has begun to produce results that may lead to changes in clinical practice. Enhanced knowledge of the genetic architecture of T2DM presents a bigger translational potential. This review summarizes the genetics and pathophysiology of T2DM, candidate-gene approaches, genome-wide association studies, personalized medicine, clinical relevance of pharmacogenetic variants associated with oral hypoglycemic agents, and paths toward personalized diabetology.

Targeting OCT3 attenuates doxorubicin-induced cardiac injury

Doxorubicin is a commonly used anticancer agent that can cause debilitating and irreversible cardiac injury. The initiating mechanisms contributing to this side effect remain unknown, and current preventative strategies offer only modest protection. Using stem-cell-derived cardiomyocytes from patients receiving doxorubicin, we probed the transcriptomic landscape of solute carriers and identified organic cation transporter 3 (OCT3) (SLC22A3) as a critical transporter regulating the cardiac accumulation of doxorubicin. Functional validation studies in heterologous overexpression models confirmed that doxorubicin is transported into cardiomyocytes by OCT3 and that deficiency of OCT3 protected mice from acute and chronic doxorubicin-related changes in cardiovascular function and genetic pathways associated with cardiac damage. To provide proof-of-principle and demonstrate translational relevance of this transport mechanism, we identified several pharmacological inhibitors of OCT3, including nilotinib, and found that pharmacological targeting of OCT3 can also preserve cardiovascular function following treatment with doxorubicin without affecting its plasma levels or antitumor effects in multiple models of leukemia and breast cancer. Finally, we identified a previously unrecognized, OCT3-dependent pathway of doxorubicin-induced cardiotoxicity that results in a downstream signaling cascade involving the calcium-binding proteins S100A8 and S100A9. These collective findings not only shed light on the etiology of doxorubicin-induced cardiotoxicity, but also are of potential translational relevance and provide a rationale for the implementation of a targeted intervention strategy to prevent this debilitating side effect.

A Whole-Body Physiologically Based Pharmacokinetic Model Characterizing Interplay of OCTs and MATEs in Intestine, Liver and Kidney to Predict Drug-Drug Interactions of Metformin with Perpetrators

Transmembrane transport of metformin is highly controlled by transporters including organic cation transporters (OCTs), plasma membrane monoamine transporter (PMAT), and multidrug/toxin extrusions (MATEs). Hepatic OCT1, intestinal OCT3, renal OCT2 on tubule basolateral membrane, and MATE1/2-K on tubule apical membrane coordinately work to control metformin disposition. Drug–drug interactions (DDIs) of metformin occur when co-administrated with perpetrators via inhibiting OCTs or MATEs. We aimed to develop a whole-body physiologically based pharmacokinetic (PBPK) model characterizing interplay of OCTs and MATEs in the intestine, liver, and kidney to predict metformin DDIs with cimetidine, pyrimethamine, trimethoprim, ondansetron, rabeprazole, and verapamil. Simulations showed that co-administration of perpetrators increased plasma exposures to metformin, which were consistent with clinic observations. Sensitivity analysis demonstrated that contributions of the tested factors to metformin DDI with cimetidine are gastrointestinal transit rate > inhibition of renal OCT2 ≈ inhibition of renal MATEs > inhibition of intestinal OCT3 > intestinal pH > inhibition of hepatic OCT1. Individual contributions of transporters to metformin disposition are renal OCT2 ≈ renal MATEs > intestinal OCT3 > hepatic OCT1 > intestinal PMAT. In conclusion, DDIs of metformin with perpetrators are attributed to integrated effects of inhibitions of these transporters.

SLC30A8 gene polymorphism rs13266634 associated with increased risk for developing type 2 diabetes mellitus in Jordanian population

BACKGROUND

Several genome-wide association studies (GWAS) have identified the single nucleotide polymorphism (SNP) rs13266634 in the Solute carrier family 30 member 8 (SLC30A8) gene as a risk factor to type 2 diabetes mellitus (T2DM). Nevertheless, other studies reported controversial findings of no significant association between the rs13266634 with T2DM. In this study, we aimed to investigate the association of this SNP with T2DM among Jordanian population in addition to define its corresponding allelic and genotypic frequencies.

METHOD

This case-control study enrolled 358 T2DM patients and 326 healthy controls who fulfilled the inclusion criteria. Blood samples were collected from all participants and were used for the rs13266634 SNP genotyping by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique.

RESULTS

We demonstrated a significant association between the C/T rs13266634 SNP and T2DM among Jordanian population. A significant difference was found between the cases and controls regarding the allelic (P = 0.003) distribution. Compared to people having T allele, those with C allele had higher risk of T2DM (OR = 1.47 ; 95% CI: 1.14 - 1.89; P = 0.003). Having a CC genotype versus TT genotype was significantly associated with increased risk to T2DM (OR = 2.44; 95% CI: 1.16 - 5.12; P = 0.019) after adjusting for age, gender, and BMI. Under the recessive model, subjects with CC genotype were more likely to have T2DM compared to those with CT or TT genotypes, (OR = 1.64; 95% CI: 1.18 - 2.26; P = 0.003) after adjusting for age, gender and BMI.

CONCLUSION

The rs13266634 SNP is significantly associated with T2DM susceptibility among Jordanian Population.

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

Diabetes is a major threat to people's health and has become a burden worldwide. Current drugs for diabetes have limitations, such as different drug responses among individuals, failure to achieve glycemic control, and adverse effects. Exploring more effective therapeutic strategies for patients with diabetes is crucial. Currently pharmacogenomics has provided potential for individualized drug therapy based on genetic and genomic information of patients, and has made precision medicine possible. Responses and adverse effects to antidiabetic drugs are significantly associated with gene polymorphisms in patients. Many new targets for diabetes also have been discovered and developed, and even entered clinical trial phases. This review summarizes pharmacogenomic evidence of some current antidiabetic agents applied in clinical settings, and highlights potential drugs with new targets for diabetes, which represent a more effective treatment in the future.

Pharmacogenetics of Type 2 Diabetes-Progress and Prospects

Type 2 diabetes mellitus (T2D) is a chronic metabolic disease resulting from insulin resistance and progressively reduced insulin secretion, which leads to impaired glucose utilization, dyslipidemia and hyperinsulinemia and progressive pancreatic beta cell dysfunction. The incidence of type 2 diabetes mellitus is increasing worldwide and nowadays T2D already became a global epidemic. The well-known interindividual variability of T2D drug actions such as biguanides, sulfonylureas/meglitinides, DPP-4 inhibitors/GLP1R agonists and SGLT-2 inhibitors may be caused, among other things, by genetic factors. Pharmacogenetic findings may aid in identifying new drug targets and obtaining in-depth knowledge of the causes of disease and its physiological processes, thereby, providing an opportunity to elaborate an algorithm for tailor or precision treatment. The aim of this article is to summarize recent progress and discoveries for T2D pharmacogenetics and to discuss the factors which limit the furthering accumulation of genetic variability knowledge in patient response to therapy that will allow improvement the personalized treatment of T2D.

Genetic Analysis of Pharmacogenomic VIP Variants of ABCB1, VDR and TPMT Genes in an Ethnically Isolated Population from the North Caucasus Living in Jordan

Background:

Differences in individual responses to the same medications remarkably differ among populations. A number of genes that play integral roles in drug responses have been designated as very important pharmacogenes (VIP), as they are responsible for differences in drug safety, efficacy, and adverse drug reactions among certain ethnic groups. Identifying the polymorphic distribution of VIP in a range of ethnic groups will be conducive to population-based personalized medicine.

Objective:

The aim of the current study is to identify the polymorphic distribution of VIP regarding the Chechen minority group from Jordan and compare their allele frequencies with other populations.

Methods:

A total of 131 unrelated Chechen individuals from Jordan were randomly recruited for blood collection. Identification of allelic and genotypic frequencies of eleven VIP variants within the genes of interest (ABCB1, VDR and TPMT) was carried out by means of the MassARRAY®System (iPLEX GOLD).

Results:

Within ABCB1, we found that the minor allele frequencies of the rs1128503 (A: 0.43), rs2032582 (A: 0.43), rs1045642 (A: 0.43). For VDR, the minor allele frequencies of rs11568820 (T: 0.18), rs1540339 (T: 0.30), rs1544410 (T: 0.41), rs2228570 (T: 0.24), rs3782905 (C: 0.28) and rs7975232 (C: 0.45). Finally, the minor allele frequencies for the TPMT rs1142345 and rs1800460 polymorphisms were found to be (C: 0.02) and (T: 0.01), respectively.

Conclusion:

Significant differences in allelic frequencies of eleven ABCB1, VDR and TPMT VIP variants were found between Jordanian Chechens and other populations. In our study, most populations that are similar to Chechens are those from South Asian, European (Finnish) and European, including: Utah residents with Northern and Western European ancestry, Toscani in Italia, Mexican ancestry in Los Angeles and Circassian from Jordan. The level of similarity between Chechens and those populations means that they might have shared high levels of gene flow in the past. The results obtained in this study will contribute to the worldwide pharmacogenomic databases and provide valuable information for future studies and better individualized treatments.

Pharmacogenomic landscape of VIP genetic variants in Jordanian Arabs and comparison with worldwide populations

The pharmacogenomics has lately become a focal field of research that investigates the influence of genetic variations of drug-metabolizing enzymes and their receptors and downstream proteins on the interindividual variability in response to medications and adverse drug reactions. Therefore, it is significantly important to study and analyze the variations in drug response between different ethnic groups and populations. The current study aimed to detect the distribution of the genotype and allele frequencies in several very important pharmacogenetic (VIP) gene polymorphisms in the Jordanian population of Arab descent. This study involved 500 unrelated Jordanian individuals of Arab descent. A total of 65 VIP variants located within 33 candidate genes were randomly selected from the PharmGKB database and genotyped using the MassARRAY (iPLEX GOLD) system. The chi-square test was used to evaluate the significant differences of minor allele and genotype frequencies between the Jordanian and other populations including CHE, ASW, CEU, CHB, CDX, GIH, GBR, JPT, LWK, MXL, TSI, YRI, CAR, and ACB. This study revealed six variants were not in Hardy Weinberg equilibrium (HWE) (P-value > 0.05) and ten SNPs showed monomorphic features. Most of the remaining forty-nine variant frequencies were significantly different from the compared ethnic groups (P-value < 0.05). The results of this study may be helpful to develop safer treatment by applying the concept of personalized medicine based on the profile of VIP pharmacogene variants of the Jordanian population of Arab descent.

Genetic Polymorphisms of Pharmacogenes among the Genetically Isolated Circassian Subpopulation from Jordan

Several genetic variants have been identified that cause variation among different populations and even within individuals of a similar descent. This leads to interindividual variations in the optimal dose of the drug that is required to sustain the treatment efficiency. In this study, 56 single nucleotide polymorphisms (SNPs) within several pharmacogenes were analyzed in 128 unrelated subjects from a genetically isolated group of Circassian people living in Jordan. We also compared these variant distributions to other ethnic groups that are available at two databases (Genome 1000 and eXAC). Our results revealed that the distribution of allele frequencies within genes among Circassians in Jordan showed similarities and disparities when compared to other populations. This study provides a powerful base for clinically relevant SNPs to enhance medical research and future pharmacogenomic studies. Rare variants detected in isolated populations can significantly guide to novel loci involved in the development of clinically relevant traits.

SLC22A1 And ATM Genes Polymorphisms Are Associated With The Risk Of Type 2 Diabetes Mellitus In Western Saudi Arabia: A Case-Control Study

Introduction

Type 2 diabetes mellitus (T2DM) is a major global health problem that is progressively affected by genetic and environmental factors. The aim of this study is to determine the influence of solute carrier family 22 member 1 (SLC22A1) rs628031 and rs461473, and ataxia telangiectasia mutated (ATM) rs11212617 polymorphisms on the risk of T2DM in Saudi Arabia by considering many parameters associated with glycemic control of T2DM, such as body mass index (BMI), fasting blood glucose, glycated hemoglobin (HbA1c), and triglyceride.

Methods

In a case-control study, genomic DNA from controls and diabetic groups was isolated and genotyped for each single-nucleotide polymorphism.

Results

There were significant correlations between T2DM and both BMI and HbA1c. Significant associations between G/G and A/G genotypes of rs628031 and rs461473 variants of SLC22A1 and high levels of HbA1c were detected. Therefore, G was predicted to be the risk allele among the assessed SLC22A1 variants. A significant correlation was observed between A/A and A/C genotypes of the rs11212617 polymorphism of ATM and elevated HbA1c. Relative risk calculation confirmed A to be the risk allele in the T2DM population.

Conclusion

Our study showed the risk of the assessed SLC22A1 and ATM variants on glycemic control parameters in diabetic patients.