In vitro-in vivo correlation of the inhibition potency of sodium-glucose cotransporter inhibitors in rat: a pharmacokinetic and pharmacodynamic modeling approach

Effects and mechanisms of SGLT2 inhibitors on the NLRP3 inflammasome, with a focus on atherosclerosis

Atherosclerosis is a lipid-driven chronic inflammatory disease that is widespread in the walls of large and medium-sized arteries. Its pathogenesis is not fully understood. The currently known pathogenesis includes activation of pro-inflammatory signaling pathways in the body, increased oxidative stress, and increased expression of cytokines/chemokines. In the innate immune response, inflammatory vesicles are an important component with the ability to promote the expression and maturation of inflammatory factors, release large amounts of inflammatory cytokines, trigger a cascade of inflammatory responses, and clear pathogens and damaged cells. Studies in the last few years have demonstrated that NLRP3 inflammatory vesicles play a crucial role in the development of atherosclerosis as well as its complications. Several studies have shown that NLRP3 binding to ligands promotes inflammasome formation, activates caspase-1, and ultimately promotes its maturation and the maturation and production of IL-1β and IL-18. IL-1β and IL-18 are considered to be the two most prominent inflammatory cytokines in the inflammasome that promote the development of atherosclerosis. SGLT2 inhibitors are novel hypoglycemic agents that also have significant antiatherosclerotic effects. However, their exact mechanism is not yet clear. This article is a review of the literature on the effects and mechanisms of SGLT2 inhibitors on the NLRP3 inflammasome, focusing on their role in antiatherosclerosis.

Does In Vitro Potency Predict Clinically Efficacious Concentrations?

The in vitro affinity of a compound for its target is an important feature in drug discovery, but what remains is how predictive in vitro properties are of in vivo therapeutic drug exposure. We assessed the relationship between in vitro potency and clinically efficacious concentrations for marketed small molecule drugs (n = 164) and how they may differ depending on therapeutic indication, mode of action, receptor type, target localization, and function. Approximately 70% of compounds had a therapeutic unbound plasma exposure lower than in vitro potency; the median ratio of exposure in relation to in vitro potency was 0.32, and 80% had ratios within the range of 0.007 to 8.7. We identified differences in the in vivo–to–in vitro potency ratio between indications, mode of action, target type, and matrix localization, and whether or not the drugs had active metabolites. The in vitro–assay variability contributions appeared to be the smallest; within the same drug target and mode of action the within‐variability was slightly broader; but both were substantially less compared with the overall distribution of ratios. These data suggest that in vitro potency conditions, estimated in vivo potency, required level of receptor occupancy, and target turnover are key components for further understanding the link between clinical drug exposure and in vitro potency.

Natural products with SGLT2 inhibitory activity: Possibilities of application for the treatment of diabetes

Diabetes mellitus currently affects as many as 400 million people worldwide, creating a heavy economic burden and stretching health care resources. A dysfunction of glucose homeostasis underlies the disease. Despite advances in the treatment of diabetes, many patients still suffer from complications and side effects; hence, development of more effective treatments for diabetes is still desirable. SGLT2 is the principle cotransporter involved in glucose reabsorption in the kidney. SGLT2 inhibition reduces glucose reabsorption by the kidney and ameliorates plasma glucose concentration. The interest in natural products that can be used for the inhibition of SGLT2 is growing. The flavonoid phlorizin, which can be isolated from the bark of apple trees, has been used as lead structure due to its inhibitory activity of SGLT1 and SGLT2. Some phlorizin-derived synthetic compounds, including canagliflozin, dapagliflozin, empagliflozin, ipragliflozin, and ertugliflozin, are approved by the food and drug administration to treat type 2 diabetes mellitus (T2DM), whereas others are under clinical trials investigation. In addition, other natural product-derived compounds have been investigated for their ability to improve blood glucose control. The present review summarizes the natural products with SGLT2 inhibitory activity, and the synthetic compounds obtained from them, and discusses their application for the treatment of diabetes.

Overexpressing cell systems are a competitive option to primary adipocytes when predicting in vivo potency of dual GPR81/GPR109A agonists

Mathematical models predicting in vivo pharmacodynamic effects from in vitro data can accelerate drug discovery, and reduce costs and animal use. However, data integration and modeling is non-trivial when more than one drug-target receptor is involved in the biological response. We modeled the inhibition of non-esterified fatty acid release by dual G-protein-coupled receptor 81/109A (GPR81/GPR109A) agonists in vivo in the rat, to estimate the in vivo EC₅₀ values for 12 different compounds. We subsequently predicted those potency estimates using EC₅₀ values obtained from concentration-response data in isolated primary adipocytes and cell systems overexpressing GPR81 or GPR109A in vitro. A simple linear regression model based on data from primary adipocytes predicted the in vivo EC₅₀ better than simple linear regression models based on in vitro data from either of the cell systems. Three models combining the data from the overexpressing cell systems were also evaluated: two piecewise linear models defining logical OR- and AND-circuits, and a multivariate linear regression model. All three models performed better than the simple linear regression model based on data from primary adipocytes. The OR-model was favored since it is likely that activation of either GPR81 or GPR109A is sufficient to deactivate the cAMP pathway, and thereby inhibit non-esterified fatty acid release. The OR-model was also able to predict the in vivo selectivity between the two receptors. Finally, the OR-model was used to predict the in vivo potency of 1651 new compounds. This work suggests that data from the overexpressing cell systems are sufficient to predict in vivo potency of GPR81/GPR109A agonists, an approach contributing to faster and leaner drug discovery.

Comparative pharmacokinetics of three SGLT-2 inhibitors sergliflozin, remogliflozin and ertugliflozin: an overview

1. Several sodium-glucose cotransporter-2 (SGLT-2) inhibitors are in clinical use for the management of type 2 diabetes. The objectives of the current review were: (a) to provide a comparative pharmacokinetics including absorption, distribution, metabolism and excretory (ADME) profiles of three SGLT-2 inhibitors namely: sergliflozin, remogliflozin and ertugliflozin; (b) to provide some perspectives on possible developmental issues. 2. Based on the half-life (t_1/2) values observed in humans, the rank order of the three SGLT-2 inhibitors was ertugliflozin (16 h) > remogliflozin (2-4 h) > sergliflozin (1-1.5 h). Therefore, while once a day dosing of ertugliflozin is possible, the other two drugs need to be dosed more frequently. Perhaps, the short t_1/2 of sergliflozin may have contributed for its discontinuation. 3. Although there was paucity of published data on the metabolism, transporter related and excretory aspects for sergliflozin, the other two drugs provided a differentiating profile. However, the compiled data suggested that there may be a minimal or no risk of pharmacokinetic drug interaction issues associated with any of the reviewed drugs. 4. Because of the crowded development pipeline and approved SGLT-2 inhibitors, the safety and efficacy of sergliflozin, remogliflozin and ertugliflozin appear to be a key from differentiation perspective.

Inhibition of the glucose transporter SGLT2 with dapagliflozin in pancreatic alpha cells triggers glucagon secretion

Type 2 diabetes (T2D) is characterized by chronic hyperglycemia resulting from a deficiency in insulin signaling, because of insulin resistance and/or defects in insulin secretion; it is also associated with increases in glucagon and endogenous glucose production (EGP). Gliflozins, including dapagliflozin, are a new class of approved oral antidiabetic agents that specifically inhibit sodium-glucose co-transporter 2 (SGLT2) function in the kidney, thus preventing renal glucose reabsorption and increasing glycosuria in diabetic individuals while reducing hyperglycemia. However, gliflozin treatment in subjects with T2D increases both plasma glucagon and EGP by unknown mechanisms. In spite of the rise in EGP, T2D patients treated with gliflozin have lower blood glucose levels than those receiving placebo, possibly because of increased glycosuria; however, the resulting increase in plasma glucagon levels represents a possible concerning side effect, especially in a patient population already affected by hyperglucagonemia. Here we demonstrate that SGLT2 is expressed in glucagon-secreting alpha cells of the pancreatic islets. We further found that expression of SLC5A2 (which encodes SGLT2) was lower and glucagon (GCG) gene expression was higher in islets from T2D individuals and in normal islets exposed to chronic hyperglycemia than in islets from non-diabetics. Moreover, hepatocyte nuclear factor 4-α (HNF4A) is specifically expressed in human alpha cells, in which it controls SLC5A2 expression, and its expression is downregulated by hyperglycemia. In addition, inhibition of either SLC5A2 via siRNA-induced gene silencing or SGLT2 via dapagliflozin treatment in human islets triggered glucagon secretion through KATP channel activation. Finally, we found that dapagliflozin treatment further promotes glucagon secretion and hepatic gluconeogenesis in healthy mice, thereby limiting the decrease of plasma glucose induced by fasting. Collectively, these results identify a heretofore unknown role of SGLT2 and designate dapagliflozin an alpha cell secretagogue.

Analysis of the efficacy of SGLT2 inhibitors using semi-mechanistic model

The Renal sodium-dependent glucose co-transporter 2 (SGLT2) is one of the most promising targets for the treatment of type 2 diabetes. Two SGLT2 inhibitors, dapagliflozin, and canagliflozin, have already been approved for use in USA and Europe; several additional compounds are also being developed for this purpose. Based on the in vitro IC₅₀ values and plasma concentration of dapagliflozin measured in clinical trials, the marketed dosage of the drug was expected to almost completely inhibit SGLT2 function and reduce glucose reabsorption by 90%. However, the administration of dapagliflozin resulted in only 30–50% inhibition of reabsorption. This study was aimed at investigating the mechanism underlying the discrepancy between the expected and observed levels of glucose reabsorption. To this end, systems pharmacology models were developed to analyze the time profile of dapagliflozin, canagliflozin, ipragliflozin, empagliflozin, and tofogliflozin in the plasma and urine; their filtration and active secretion from the blood to the renal proximal tubules; reverse reabsorption; urinary excretion; and their inhibitory effect on SGLT2. The model shows that concentration levels of tofogliflozin, ipragliflozin, and empagliflozin are higher than levels of other inhibitors following administration of marketed SGLT2 inhibitors at labeled doses and non-marketed SGLT2 inhibitors at maximal doses (approved for phase 2/3 studies). All the compounds exhibited almost 100% inhibition of SGLT2. Based on the results of our model, two explanations for the observed low efficacy of SGLT2 inhibitors were supported: (1) the site of action of SGLT2 inhibitors is not in the lumen of the kidney's proximal tubules, but elsewhere (e.g., the kidneys proximal tubule cells); and (2) there are other transporters that could facilitate glucose reabsorption under the conditions of SGLT2 inhibition (e.g., other transporters of SGLT family).