SGLT2: a potential target for the pharmacogenetics of Type 2 diabetes?

Natural hypoglycaemic bioactives: Newer avenues and newer possibilities

The incidences of endocrine and metabolic disorders like diabetes have increased worldwide. Several proposed molecular pathways mechanisms for the management of diabetes have been identified, but glycaemic control is still a challenging task in the drug discovery process. Most of the drug discovery processes lead to numerous scaffolds that are prominent in natural products. The review deals with the natural bioactives as an α-amylase inhibitors, α-glucosidase inhibitors, protein tyrosine phosphatase-1B inhibitors, dipeptidyl peptidase-IV inhibitors, G-protein coupled receptors-40 agonists, PPAR-γ agonists and the activators of 5'-adenosine monophosphate-activated protein kinase and glucokinase. So, in this review, we focused on the hypoglycaemic bioactives, which will assist scientific developers, traditional medicinal practitioners, and readers to discover some potent antidiabetic molecules. Strategies like chemometric approaches, scaffold hopping, and total synthesis of natural products by group modification or ring opening/closing mechanism could be useful for the development of novel hit/lead antidiabetic molecules. The study concludes that each phyto molecule inherits a potential to get explored by repurposing techniques for various antidiabetic targets and offer an alternative antidiabetic therapeutic medicinal potential.

Role of SLC5A2 polymorphisms and effects of genetic polymorphism on sodium glucose cotransporter 2 inhibitorsinhibitor response

Type 2 diabetes mellitus (T2DM) is a complex metabolic disease characterized by hyperglycaemia. T2DM is a highly heterogeneous polygenic disease. Due to genetic variation, variations in lifestyle and other environmental exposures, there are certain variations in the phenotype of T2DM patients. Sodium glucose cotransporter 2 (SGLT2) inhibitors are novel hypoglycaemic agents that increase urinary glucose excretion by inhibiting glucose reabsorption in the proximal tubules of the kidney. For glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors, studies have confirmed a variety of gene variants that may modify their effects. For SGLT2 inhibitors, research has focused on the SLC5A2 gene encoding SGLT2 and UGT1A9 gene polymorphisms affecting SGLT2 inhibitor metabolism. The SLC5A2 polymorphism rs9934336 have been associated with decreased HbA1c during the oral glucose tolerance test. Common variants of the SLC5A2 gene are related to blood glucose and insulin concentrations, but not glucagon concentrations. SLC5A2 rs9934336 and rs3116150 are related to a lower risk of heart failure. SGLT2 inhibitor exposure of UGT1A9*3 carriers is commonly higher than that of noncarriers, while these effects commonly have no obvious clinical significance on SGLT2 inhibitor pharmacokinetics. In terms of efficacy, general SLC5A2 variants show no significant effect on the response to the SGLT2 inhibitor empagliflozin. At present, research on the relationship between genetic polymorphisms and the efficacy of SGLT2 inhibitors is limited. The main purpose of this review is to elucidate the general effects of SGLT2 polymorphisms and the association between polymorphisms and the treatment response to SGLT2 inhibitors.

The current role of sodium-glucose cotransporter 2 inhibitors in type 2 diabetes mellitus management

Type 2 diabetes mellitus (T2DM) is a chronic, complex metabolic disease characterized by chronic hyperglycemia causing from insufficient insulin signaling because of insulin resistance or defective insulin secretion, and may induce severe complications and premature death. Sodium-glucose cotransporter-2 (SGLT2) inhibitors are oral drugs used to reduce hyperglycemia in patients with T2DM, including empagliflozin, ertugliflozin, dapagliflozin and canagliflozin. The primary objective of this article is to examine the clinical benefit, safety, and tolerability of the four SGLT2 inhibitors approved by the US FDA. SGLT2 inhibitors increase urinary glucose excretion via inhibiting SGLT2 to decrease renal reabsorption of filtered glucose and reduce the renal threshold for glucose. Rather than stimulating insulin release, SGLT2 inhibitors improve β-cell function by improving glucotoxicity, as well as reduce insulin resistance and increase insulin sensitivity. Early clinical trials have confirmed the beneficial effects of SGLT2 in T2DM with acceptable safety and excellent tolerability. In recent years, SGLT2 inhibitors has been successively approved by the FDA to decrease cardiovascular death and decrease the risk of stroke and cardiac attack in T2DM adults who have been diagnosed with cardiovascular disease, treating heart failure (HF) with reduced ejection fraction and HF with preserved ejection fraction, and treat diabetic kidney disease (DKD), decrease the risk of hospitalization for HF in T2DM and DKD patients. SGLT2 inhibitors are expected to be an effective treatment for T2DM patients with non alcoholic fatty liver disease. SGLT2 inhibitors have a similar safety profile to placebo or other active control groups, with major adverse events such as Ketoacidosis or hypotension and genital or urinary tract infections.

Pilot study in pharmacogenomic management of empagliflozin in type 2 diabetes mellitus patients

Background

Type 2 diabetes mellitus (T2DM) is a metabolic disorder in which the patients with high blood sugar develop insufficient insulin secretion or insulin resistance. The solute carrier family, 5 member 2 (SLC5A2) gene is a member of sodium/glucose transporter family which can reduce heart and kidney problems. The current study aims to look into any association between rs11646054 variant in SLC5A2 gene and the anti-diabetic efficacy and safety of empagliflozin.

Methods

14 T2DM who failed to respond to previous treatments, empagliflozin 10 mg was added for 6 months. Genotyping of the rs11646054 variant of SLC5A2 gene was performed by polymerase chain reaction (PCR) followed by Sanger sequencing.

Results

Although hemoglobin A1c (HbA1c) and low-density lipoprotein (LDL) were not significantly different, but the mean fasting blood sugar (FBS), 2-h post prandial (2hpp), albumin-to-creatinine ratio (ACR), and total cholesterol (TC) were significantly decreased after 6 months empagliflozin treatment. There was a significant difference in the mean final reductions in FBS level among genotypes. It's important to mention that those who were GG homozygotes had a tendency to have more decrements.

Conclusions

The study results indicate that effects of variation in SLC5A2 (rs11646054) on the clinical efficacy of empagliflozin were negligible.

Are SGLT2 polymorphisms linked to diabetes mellitus and cardiovascular disease? Prospective study and meta-analysis

Inhibition of the sodium glucose co-transporter 2 (SGLT2) reduces cardiovascular morbidity, and mortality in patients with type 2 diabetes mellitus (T2DM) with atherosclerotic, cardiovascular disease. So far, a link between common genetic variations of the SGLT2 encoding gene SLC5A2 and glucose homeostasis as well as cardiovascular disease has not been established. The present study, therefore, aimed to investigate SLC5A2 single nucleotide polymorphisms (SNPs) in relation to type 2 diabetes and coronary artery disease (CAD) and prospectively the incidence of cardiovascular events. We genotyped the SLC5A2 tagging SNPs rs9934336, rs3813008, and rs3116150 in a total of 1684 high risk cardiovascular patients undergoing coronary angiography, including 400 patients with T2DM. Additionally, we performed a meta-analysis combining results from the present study and the literature. Variant rs9934336 was significantly associated with decreased HbA1c (P = 0.023). Further, rs9934336 was significantly inversely associated with the presence of T2DM in univariate (OR = 0.82 [0.68-0.99]; P = 0.037) as well as in multivariate analysis (OR = 0.79 [0.65-0.97]; P = 0.023). The association between rs9934336 and T2DM was confirmed in a meta-analysis including results from two previous observations which by themselves had failed to show a significant association of the polymorphism with T2DM (OR = 0.86 [0.78-0.95]; P = 0.004). Polymorphisms rs3813008 and rs3116150 were associated neither with glycemic parameters nor with T2DM. None of the SNPs tested was significantly associated with the baseline presence of CAD or the incidence of cardiovascular events. We conclude that genetic variation within the SLC5A2 gene locus is significantly related to the manifestation of T2DM.

Influence of common polymorphisms in the SLC5A2 gene on metabolic traits in subjects at increased risk of diabetes and on response to empagliflozin treatment in patients with diabetes

OBJECTIVE

Inhibition of the renal sodium-glucose cotransporter 2 (SGLT2) is a novel concept in the therapy of diabetes mellitus. In this study, we first assessed whether common single nucleotide polymorphisms (SNPs) in the SGLT2-encoding gene SLC5A2 affect diabetes-related metabolic traits in subjects at risk for type 2 diabetes and, second, whether these have pharmacogenetic relevance by interfering with the response to empagliflozin treatment in patients with type 2 diabetes.

PATIENTS AND METHODS

Samples from a metabolically well-phenotyped cross-sectional study population (total N=2600) at increased risk for type 2 diabetes and pooled pharmacogenetic samples from patients from four phase III trials of empagliflozin (in total: 603 receiving empagliflozin, 305 receiving placebo) were genotyped for five common SNPs (minor allele frequencies ≥5%) present in the SLC5A2 gene locus.

RESULTS

In the cross-sectional study, none of the SLC5A2 SNPs significantly influenced metabolic traits such as body fat, insulin sensitivity/resistance, insulin release, HbA1c, plasma glucose, or systolic blood pressure when multiple testing was taken into account (all P≥0.0083). Further, no relevant effect on response to treatment with empagliflozin on HbA1c, fasting glucose, weight, or systolic blood pressure was observed for the SNPs tested in the pharmacogenetic study.

CONCLUSION

Common genetic variants in the SLC5A2 gene neither affects diabetes-related metabolic traits nor have a clinically relevant impact on response to treatment with the SGLT2 inhibitor empagliflozin.

Evaluation of the pharmacokinetics, pharmacodynamics and clinical efficacy of empagliflozin for the treatment of type 2 diabetes

INTRODUCTION

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are the latest class of drugs to be introduced for the treatment of type 2 diabetes mellitus. These drugs improve glycemic control by increasing urinary glucose excretion and exert additional benefits of weight loss and blood pressure reductions. Areas covered: This review outlines the background to SGLT2 inhibitors and provides details on the pharmacokinetics, pharmacodynamics and clinical efficacy of empagliflozin and discusses the cardiovascular outcome trial. Expert opinion: Empagliflozin was the first from a new group of antidiabetic drugs to show benefits in a cardiovascular outcome trial. There were significant reductions in cardiovascular and all-cause mortality and empagliflozin treatment reduced hospitalizations for heart failure and reduced the progression of diabetic nephropathy. These benefits, which occurred at a very early stage during the study, may be related to a reduction in circulating volume or changes in metabolic fuel utilization in the heart and kidneys. Whether these effects are shared by other SGLT2 inhibitors is not yet known, but there may be differences between drugs related to selectivity for inhibition of SGLT2 compared to SGLT1 or other pharmacological effects. Currently the outcome evidence is only available to support the use of empagliflozin in this drug class.

Cardiac Myocyte KLF5 Regulates Ppara Expression and Cardiac Function

RATIONALE

Fatty acid oxidation is transcriptionally regulated by peroxisome proliferator-activated receptor (PPAR)α and under normal conditions accounts for 70% of cardiac ATP content. Reduced Ppara expression during sepsis and heart failure leads to reduced fatty acid oxidation and myocardial energy deficiency. Many of the transcriptional regulators of Ppara are unknown.

OBJECTIVE

To determine the role of Krüppel-like factor 5 (KLF5) in transcriptional regulation of Ppara.

METHODS AND RESULTS

We discovered that KLF5 activates Ppara gene expression via direct promoter binding. This is blocked in hearts of septic mice by c-Jun, which binds an overlapping site on the Ppara promoter and reduces transcription. We generated cardiac myocyte-specific Klf5 knockout mice that showed reduced expression of cardiac Ppara and its downstream fatty acid metabolism-related targets. These changes were associated with reduced cardiac fatty acid oxidation, ATP levels, increased triglyceride accumulation, and cardiac dysfunction. Diabetic mice showed parallel changes in cardiac Klf5 and Ppara expression levels.

CONCLUSIONS

Cardiac myocyte KLF5 is a transcriptional regulator of Ppara and cardiac energetics.