Differential increments of basal glucagon-like-1 peptide concentration among SLC47A1 rs2289669 genotypes were associated with inter-individual variability in glycaemic response to metformin in Chinese people with newly diagnosed Type 2 diabetes

GLP1R rs3765467 Polymorphism Is Associated with the Risk of Early Onset Type 2 Diabetes

Objective

To investigate the relationship between glucagon-like peptide-1 receptor gene polymorphisms and susceptibility to early onset type 2 diabetes.

Methods

Samples from 316 type 2 diabetes patients with early onset type 2 diabetes (n = 137) and late-onset type 2 diabetes (n = 179) and 145 nondiabetic individuals were analyzed. Multiplex PCR combined with resequencing Hi-Reseq technology was used to detect single nucleotide polymorphisms of the glucagon-like peptide-1 receptor gene, and the allele frequency, genotype distribution, and clinical parameters were analyzed between each diabetes subgroup and the control group.

Results

Sixteen single nucleotide polymorphisms were identified in the exonic region of the glucagon-like peptide-1 receptor gene according to the minor allele frequency (MAF > 0.05) in the participants. Among these, the glucagon-like peptide-1 receptor rs3765467 (G⟶A) mutation was statistically associated with early onset type 2 diabetes. Compared with that of the GG carriers, carriers of genotype AA at rs3765467 had a decreased risk of early onset type 2 diabetes after adjusting for sex and body mass index. In the dominant model, the frequencies of the rs3765467 AA + GA genotype were significantly decreased in the early onset type 2 diabetes group, and carriers of genotype AA + GA at rs3765467 had a decreased risk of early onset type 2 diabetes after adjusting for sex and body mass index. Moreover, fasting C peptide levels were significantly higher in GA + AA genotype carriers than those in GG genotype carriers.

Conclusion

The glucagon-like peptide 1 receptor rs3765467 polymorphism was significantly associated with age at type 2 diabetes diagnosis and thus may be used as a marker to screen and detect individuals at risk of developing early onset type 2 diabetes.

Association of the SLC47A1 Gene Variant With Responses to Metformin Monotherapy in Drug-naive Patients With Type 2 Diabetes

CONTEXT

Although metformin is the first-line treatment for type 2 diabetes, the blood sugar-lowering effect of metformin varies among populations. SLC47A1 plays an important role in metformin pharmacokinetics and pharmacodynamics.

OBJECTIVE

We performed a systematic review and meta-analysis to investigate the association between SLC47A1 rs2289669 (G > A) and the metformin response in drug-naive patients with type 2 diabetes.

METHODS

Studies published until January 27, 2022, were retrieved from Cochrane CENTRAL, Embase, PubMed, and Web of Science. Two reviewers independently screened titles, abstracts, and full-text articles. Studies conducted in newly diagnosed or drug-naive patients with type 2 diabetes who received metformin monotherapy were included. A total of 6 studies involving 953 patients were included in this meta-analysis. We extracted the study characteristics and changes in glycated hemoglobin (HbA1c) levels before and after treatment according to the SLC47A1 rs2289669 genotype. Changes in HbA1c levels were analyzed using mean differences (MDs) and 95% CIs. SLC47A1 rs2289669 was associated with changes in HbA1c levels (A carrier vs GG; MD = -0.55; 95% CI, -0.91 to - 0.20; I² = 63%). The sensitivity analysis yielded similar results to the main analysis (MD range, -0.64 to -0.37). When comparing all 3 genotypes, there were significant differences in HbA1c level changes between AA vs GG and GA vs GG, but not in GA vs AA.

CONCLUSION

This meta-analysis showed that SLC47A1 rs2289669 is associated with the glycemic response to metformin in drug-naive patients with type 2 diabetes.

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.

Lack of effect of the SLC47A1 and SLC47A2 gene polymorphisms on the glycemic response to metformin in type 2 diabetes mellitus patients

Background This work aimed to evaluate the influence of single nucleotide polymorphisms (SNPs) in the SLC47A1 (922-158G>A; rs2289669) and SLC47A2 (-130G>A; rs12943590) genes on the relative change in HbA1c in type 2 diabetes mellitus (T2DM) patients of South India who are taking metformin as monotherapy. It also aims to study the effects of these SNPs on the dose requirement of metformin for glycemic control and the adverse effects of metformin. Methods Diabetes patients on metformin monotherapy were recruited based on the eligibility criteria (n=105). DNA was extracted and genotyping was performed with a real-time PCR system using TaqMan® SNP genotyping assay method. The HbA1c levels were measured using Bio-Rad D-10™ Hemoglobin Analyzer. Results After adjusting for multiple comparisons (Bonferroni correction) the difference found in the glycemic response between the "GG" genotype and "AG/AA" genotype groups of the SLC47A2 gene was not significant (p=0.027; which was greater than the critical value of 0.025). Patients with "GG" genotype showed a 5.5% decrease in HbA1c from baseline compared to those with the "AG/AA" genotype (0.1% increase). The SNP in the SLC47A1 gene also did not influence the glycemic response to metformin (p=0.079). The median dose requirements based on the genotypes of the rs12943590 variant (p=0.357) or rs2289669 variant (p=0.580) were not significantly different. Similarly, there was no significant difference in the occurrence of adverse effects across the genotypes in both the SLC47A1 (p=0.615) and SLC47A2 (p=0.309) genes. Conclusions The clinical response to metformin was not associated with the SNPs in the SLC47A1 and SLC47A2 genes coding for the multidrug and toxin extrusion protein (MATE) transporters. Furthermore, the studied SNPs had no influence on the dose requirement or adverse effects of metformin.