Common variation in the sodium/glucose cotransporter 2 gene SLC5A2 does neither affect fasting nor glucose-suppressed plasma glucagon concentrations

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.

[Clinical effectiveness and pharmacokinetics of gliflozin from the point of view of individual genetic characteristics: A review]

A review of publications devoted to the analysis of genetic polymorphisms and features of the functioning of genes that affect the pharmacokinetics and pharmacodynamics of sodium-glucose cotransporter-2 inhibitors (SGLT2i) is presented. Objective of the study was to reveal information about genes whose polymorphism may affect the effectiveness of SGLT2i. The review was carried out in accordance with the PRISMA 2020 recommendations, the search for publications was carried out in the PubMed databases (including Medline), Web of Science, as well as Russian scientific electronic libraries eLIBRARY.RU from 1993 to 2022. Polymorphisms in the structure of several genes (SLC5A2, UGT1A9, ABCB1, PNPLA3) have been described that may affect the treatment of type 2 diabetes mellitus complicated by diseases such as chronic heart failure, chronic kidney disease, or non-alcoholic fatty liver disease. The information found on the genetic features of the development of the effects of SGLT2i is limited to a description of the differences in their pharmacokinetics. The relevance of currently available pharmacogenetic studies is largely constrained by small sample sizes.

Effects of a New Group of Antidiabetic Drugs in Metabolic Diseases

The prevalence of type 2 diabetes mellitus (T2DM) is rising in the general population. This increase leads to higher cardiovascular risk, with cardiovascular diseases being the main cause of death in diabetic patients. New therapeutic weapons for diabetes mellitus are now available. Sodium-glucose cotransporter type 2 (SGLT2) inhibitors are novel drugs that are widely used due to their strong benefit in preventing hospitalization for decompensated heart failure and renal protection, limiting the deterioration of the glomerular filtration rate, independently of the presence of diabetes mellitus. These drugs have also shown benefit in the prevention of atherosclerotic cardiovascular events and cardiovascular mortality in diabetic patients with established cardiovascular disease. On the other hand, patients with T2DM usually present a high burden of associated comorbidities. Some of these entities are arterial hypertension, dyslipidemia, hyperuricemia, obesity, non-alcoholic fatty liver disease (NAFLD), polycystic ovary syndrome (PCOS), vascular aging, respiratory diseases, or osteoporosis and fractures. Healthcare professionals should treat these patients from an integral point of view, and not manage each pathology separately. Therefore, as potential mechanisms of SGLT2 inhibitors in metabolic diseases have not been fully reviewed, we conducted this review to know the current evidence of the use and effect of SGLT2 inhibitors on these metabolic diseases.

Polymorphisms in glucose homeostasis genes are associated with cardiovascular and renal parameters in patients with diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) has become the major cause of end-stage kidney disease and is associated to an extremely high cardiovascular (CV) risk.

METHODS

We screened 318 DN patients for 23 SNPs in four glucose transporters (SLC2A1, SLC2A2, SLC5A1 and SLC5A2) and in KCNJ11 and ABCC8, which participate in insulin secretion. Regression models were utilised to identify associations with renal parameters, atherosclerosis measurements and CV events. In addition, 506 individuals with normal renal function were also genotyped as a control group.

RESULTS

In the patient's cohort, common carotid intima media thickness values were higher in carriers of ABCC8 rs3758953 and rs2188966 vs. non-carriers [0.78(0.25) vs. 0.72(0.22) mm, p < 0.05 and 0.79(0.26) vs. 0.72(0.22) mm, p < 0.05], respectively. Furthermore, ABCC8 rs1799859 was linked to presence of plaque in these patients [1.89(1.03-3.46), p < 0.05]. Two variants, SLC2A2 rs8192675 and SLC5A2 rs9924771, were associated with better [OR = 0.49 (0.30-0.81), p < 0.01] and worse [OR = 1.92 (1.15-3.21), p < 0.05] CV event-free survival, respectively. With regard to renal variables, rs841848 and rs710218 in SLC2A1, as well as rs3813008 in SLC5A2, significantly altered estimated glomerular filtration rate values [carriers vs. non-carriers: 30.41(22.57) vs. 28.25(20.10), p < 0.05; 28.95(21.11) vs. 29.52(21.66), p < 0.05 and 32.03(18.06) vs. 28.14(23.06) ml/min/1.73 m², p < 0.05]. In addition, ABCC8 rs3758947 was associated with higher albumin-to-creatinine ratios [193.5(1139.91) vs. 160(652.90) mg/g, p < 0.05]. The epistasis analysis of SNP-pairs interactions showed that ABCC8 rs3758947 interacted with several SNPs in SLC2A2 to significantly affect CV events (p < 0.01). No SNPs were associated with DN risk.

CONCLUSIONS

Polymorphisms in genes determining glucose homeostasis may play a relevant role in renal parameters and CV-related outcomes of DN patients.

Treatment Response to SGLT2 Inhibitors: From Clinical Characteristics to Genetic Variations

SGLT2 (sodium-glucose cotransporter 2) inhibitors are a new class of antihyperglycaemic drugs that act on the proximal tubules of the kidney. They have shown efficacy in the management of diabetes mellitus type 2 and their cardiovascular and renal safety have been extensively investigated and confirmed in clinical trials. However, inter-individual differences in response to treatment with SGLT2 inhibitors may present in everyday clinical practice, and good predictors of glycemic response and the risk for adverse events in an individual patient are lacking. As genetic variability of SGLT2 may influence the treatment response, pharmacogenetic information could support the choice of the most beneficial treatment strategy in an individual patient. This review focuses on the clinical and genetic factors that may influence the treatment response to SGLT2 inhibitors in type 2 diabetes patients with comorbid conditions.

Integrating genomics with biomarkers and therapeutic targets to invigorate cardiovascular drug development

Drug development in cardiovascular disease is stagnating, with lack of efficacy and adverse effects being barriers to innovation. Human genetics can provide compelling evidence of causation through approaches such as Mendelian randomization, with genetic support for causation increasing the probability of a clinical trial succeeding. Mendelian randomization applied to quantitative traits can identify risk factors for disease that are both causal and amenable to therapeutic modification. However, important differences exist between genetic investigations of a biomarker (such as HDL cholesterol) and a drug target aimed at modifying the same biomarker of interest (such as cholesteryl ester transfer protein), with implications for the methodology, interpretation and application of Mendelian randomization to drug development. Differences include the comparative nature of the genetic architecture - that is, biomarkers are typically polygenic, whereas protein drug targets are influenced by either cis-acting or trans-acting genetic variants - and the potential for drug targets to show disease associations that might differ from those of the biomarker that they are intended to modify (target-mediated pleiotropy). In this Review, we compare and contrast the use of Mendelian randomization to evaluate potential drug targets versus quantitative traits. We explain how genetic epidemiological studies can be used to assess the aetiological roles of biomarkers in disease and to prioritize drug targets, including designing their evaluation in clinical trials.

Clinical and genetic determinants of urinary glucose excretion in patients with diabetes mellitus

AIMS/INTRODUCTION

Glucosuria is a representative symptom in diabetes patients with poor glycemic control and in those treated with sodium-glucose cotransporter 2 inhibitors. Renal threshold levels of glucose excretion are known to vary among individuals, but factors contributing to glucosuria are not well characterized. The present study aimed to clarify clinical and genetic determinants of glucosuria in individuals with diabetes mellitus.

MATERIALS AND METHODS

The 24-h urinary glucose excretion was measured in 135 hospitalized patients on admission, with continuous measurement for five consecutive days in 75 patients. Genetic and clinical factors contributing to glucosuria were studied. As a genetic factor, SLC5A2 polymorphism was genotyped. A total of 476 participants (266 participants with type 2 diabetes and 210 healthy controls) were additionally genotyped for the association study of SLC5A2 with type 2 diabetes. A meta-analysis was carried out with the present study and previous association studies.

RESULTS

Multiple regression analysis showed that the independent variables of average blood glucose (β = 0.41, P = 1.4 × 10-7 ), estimated glomerular filtration rate (β = 0.28, P = 6.0 × 10-5 ), sex (β = 0.28, P = 5.7 × 10-5 ) and SLC5A2 rs9934336 polymorphism (β = 0.17, P = 0.02) were significantly correlated with urinary glucose excretion. The frequency of the A allele of rs9934336 tended to be lower in participants with type 2 diabetes than in controls (odds ratio 0.78, 95% confidence interval 0.53-1.13, not significant), and meta-analysis showed a significant association between the A allele and type 2 diabetes (summary odds ratio for minor allele [A] 0.86, 95% confidence interval 0.78-0.94, P < 0.002).

CONCLUSIONS

Blood glucose, estimated glomerular filtration rate, sex and SLC5A2 polymorphism were independent determinants of glucosuria in diabetes mellitus.

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.

A Polygenic Risk Score of Lipolysis-Increasing Alleles Determines Visceral Fat Mass and Proinsulin Conversion

CONTEXT

Primary dysregulation of adipose tissue lipolysis caused by genetic variation and independent of insulin resistance could explain unhealthy body fat distribution and its metabolic consequences.

OBJECTIVE

To analyze common single nucleotide polymorphisms (SNPs) in 48 lipolysis-, but not insulin-signaling-related genes, to form polygenic risk scores of lipolysis-associated SNPs, and to investigate their effects on body fat distribution, glycemia, insulin sensitivity, insulin secretion, and proinsulin conversion.

STUDY DESIGN, PARTICIPANTS, AND METHODS

SNP array, anthropometric, and metabolic data were available from up to 2789 participants without diabetes of the Tübingen Family study of type 2 diabetes characterized by oral glucose tolerance tests. In a subgroup (n = 942), magnetic resonance measurements of body fat stores were available.

RESULTS

We identified insulin-sensitivity-independent nominal associations (P < 0.05) of SNPs in 10 genes with plasma free fatty acids (FFAs), in 7 genes with plasma glycerol and in 6 genes with both, plasma FFAs and glycerol. A score formed of the latter SNPs (in ADCY4, CIDEA, GNAS, PDE8B, PRKAA1, PRKAG2) was associated with plasma FFA and glycerol measurements (1.4*10-9 ≤ P ≤ 1.2*10-5), visceral adipose tissue mass (P = 0.0326), and proinsulin conversion (P ≤ 0.0272). The more lipolysis-increasing alleles a subject had, the lower was the visceral fat mass and the lower the proinsulin conversion.

CONCLUSIONS

We found evidence for a genetic basis of adipose tissue lipolysis resulting from common SNPs in CIDEA, AMP-activated protein kinase subunits, and cAMP signaling components. A genetic score of lipolysis-increasing alleles determined lower visceral fat mass and lower proinsulin conversion.

Pharmacogenetics of oral antidiabetic therapy

Type 2 diabetes prevalence is still on the rise worldwide. Antidiabetic drugs are widely prescribed to patients with Type 2 diabetes. Most patients start with metformin which is mostly well tolerated. However, a high percentage of patients fail to achieve glycemic control. The effectiveness of metformin as well as most other antidiabetic drugs depends among other factors on interindividual genetic differences that are up to now ignored in the treatment of Type 2 diabetes. Interestingly, many genes influencing the effectiveness of antidiabetic drugs are Type 2 diabetes risk genes making matters worse. Here, we shed light on these interindividual genetic differences.