Polymorphisms of the KCNQ1 gene are associated with the therapeutic responses of sulfonylureas in Chinese patients with type 2 diabetes

Clinical research progress on β-cell dysfunction in T2DM development in the Chinese population

The prevalence of type-2 diabetes mellitus (T2DM) has increased over 10-fold in the past 40 years in China, which now has the largest T2DM population in the world. Insulin resistance and β-cell dysfunction are the typical features of T2DM. Although both factors play a role, decreased β-cell function and β-cell mass are the predominant factors for progression to T2DM. Considering the differences between Chinese T2DM patients and those of other ethnicities, it is important to characterize β-cell dysfunction in Chinese patients during T2DM progression. Herein, we reviewed the studies on the relationships between β-cell function and T2DM progression in the Chinese population and discussed the differences among individuals of varying ethnicities. Meanwhile, we summarized the risk factors and current treatments of T2DM in Chinese individuals and discussed their impacts on β-cell function with the hope of identifying a better T2DM therapy.

Pharmacogenomics of GLP-1 receptor agonists: Focus on pharmacological profile

Type 2 Diabetes mellitus (T2DM) is a multifactorial metabolic disorder also known as a silent killer disease. Macrovascular and microvascular complications associated with diabetes worsen the condition leading to higher comorbidity and mortality rate. Currently, available treatment strategies for diabetes include biguanides, sulfonylureas, alpha-glucosidase inhibitors, thiazolidinediones, insulin and its analogs, DPP-4 (dipeptidyl-peptidase-4) inhibitors, SGLT-2 inhibitors, and Glucagon Like Peptide-1 receptor agonists (GLP-1RAs). Synthetic agonists of GLP-1 hormone, GLP-1RAs are an emerging class of anti-diabetic drugs which target the pathophysiology of diabetes through various mechanisms and at multiple sites. They promote insulin secretion from beta cells, and the proliferation of beta cells inhibits glucagon secretion, delays gastric emptying and induces satiety. However, treatment is reported to be associated with inter-individual variations and adverse drug reactions, which are also influenced by genetic variations. There have been a few pharmacogenetic studies have been carried out on this drug class. This review discusses all the available GLP-1RAs, their pharmacokinetics, pharmacodynamics and genetic variation affecting the inter-individual variation.

Pharmacogenomics of sulfonylureas in type 2 diabetes mellitus; a systematic review

Purpose

Genetic factors have a role in response to a target medication (personalized medicine). This study aimed to review available evidence about the relationship between gene variants and therapeutic response to sulfonylureas in type 2 diabetes, systematically.

Methods

An extensive search was done in Scopus, PubMed, and Web of Science with specific search strategy in the field from the beginning until the 1st of Jan. 2021. After sending records to endnote software and removing duplicate records remained documents were screened by title and abstract. Full texts of remained documents were assessed after removing un-related records. Required data was extracted from remained documents and records were categorized according to gene/SNP studied.

Results

Finally, 26 studies with 9170 T2DM patients with a mean age of 59.47 ± 6.67 (49.7-75.2 years) remained. The most contribution was from China, Slovakia and Greece, respectively and the most genes studied were CYP2C9, KCNJ11, and both KCNQ1 and ABCC8 with 10, 7, and 4 articles, respectively. Also, rs1799853 and rs1057910 (each with seven studies), rs5219 with six studies and CYP2C9*1(with four articles), respectively were the most common variants investigated. Studies about each gene obtained different positive or negative results and were not consistent.

Conclusion

Considering heterogeneity between SFUs pharmacogenomic studies regarding the method, sample size, population, gene/variant studied, and outcome and findings, these studies are not conclusive and need further studies.

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

Background

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

Methods

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

Results

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

Conclusions

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

KCNQ1 rs2237895 polymorphism is associated with the therapeutic response to sulfonylureas in Iranian type 2 diabetes mellitus patients

Background and Aims

Sulfonylureas are the most secondary prescribed oral anti-diabetic drug. Understanding its genetic role in pharmacodynamics can elucidate a considerable knowledge about personalized treatment in type 2 diabetes patients. This study aimed to assess the impact of KCNQ1 variants on sulfonylureas response among type 2 diabetes Iranian patients.

Methods and Results

100 patients were recruited who were under sulfonylureas therapy for six months. 50 responder and 50 non-responder patients were selected. KCNQ1 variants were determined by the RFLP method, and their role in treatment response was assessed retrospectively. Patients with rs2237895 CC and AC genotypes demonstrated a significant decrement in FBS and HbA1c after treatment over patients with AA genotypes (All P < 0.001). Compared to the A allele, the odds ratio for treatment success between carriers with rs2237895 C allele was 4.22-fold (P < 0.001). Patients with rs2237892 CT heterozygous genotype exhibit a higher reduction rate in HbA1c and FBS than CC homozygotes (P=0.064 and P=0.079, respectively). The rs2237892 T allele carriers showed an odds ratio equals to 2.83-fold over C allele carriers in the responder group compared to the non-responder group (p=0.081).

Conclusion

Findings suggest that the KCNQ1 rs2237895 polymorphism is associated with the sulfonylureas response on Iranian type 2 diabetes patients.

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.

Clinical and genetic predictors of secondary sulfonylurea failure in Type 2 diabetes patients: the SUCLINGEN study

Background: Due to several limitations in the study designs of sulfonylurea pharmacogenomics studies, we investigated the clinical and genetic predictors of secondary sulfonylurea failure in Type 2 diabetes patients. Materials & methods: Patients receiving the maximum sulfonylurea and metformin doses for >1 year were enrolled. Secondary sulfonylurea failure was defined as HbA1c >7.0% (>53 mmol/mol) after a 12-month follow-up. Results: By multivariate analysis, increased insulin resistance (HOMA2-IR), baseline HbA1c >7.0%, residing in eastern Peninsular Malaysia, and the CC genotype of rs757110 ABCC8 gene polymorphism were independent predictors of secondary sulfonylurea failure (p < 0.05) while sulfonylurea-induced hypoglycemia was protective against such failure (p < 0.05). Conclusion: Sulfonylurea does not benefit patients with an increased risk of secondary sulfonylurea failure.

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.

KCNQ1 gene polymorphism is associated with glycaemic response to treatment with DPP-4 inhibitors

AIMS

Only afew gene variants were associated with the response to dipeptidylpeptidase-4 inhibitors (DPP4I). KCNQ1 gene variants were previously related both to type 2 diabetes (T2D) and incretin effect. We hypothesized that T2D related KCNQ1 variants would be associated with smaller glucose-lowering effect of DDP4I.

METHODS

We performed a retrospective study in 137 Caucasian subjects with T2D who were followed for 6months after initiation of DPP4I treatment. Genotyping for KCNQ1 rs163184 and rs151290 was performed using PCR-HRMA and PCR-RFLP methods, respectively. The main clinical outcome was reduction in HbA1c (ΔHbA1c) after 6-month DPP4I treatment.

RESULTS

KCNQ1 rs163184 T>G variant was associated with the response to DPP4I treatment in genetic additive model (β=-0.30, p=0.022). For each G allele in the rs163184 genotype, we observed a 0.3% (3.3mmol/mol) less reduction in HbA1c during treatment with a DPP4I. Both the GG homozygotes and G-allele carriers had significantly smaller HbA1c reduction in comparison with the TT homozygotes.

CONCLUSIONS

KCNQ1 rs163184 T>G variant was associated with a reduced glycaemic response to DPP4I. The difference of 0.6% (6.5mmol/mol) in HbA1c reduction between the TT and GG homozygotes might be of clinical significance if replicated in further studies.