Remogliflozin etabonate, in a novel category of selective low-affinity sodium glucose cotransporter (SGLT2) inhibitors, exhibits antidiabetic efficacy in rodent models

Role of glucotoxicity and lipotoxicity in the pathophysiology of Type 2 diabetes mellitus and emerging treatment strategies

Type 2 diabetes mellitus is a disease characterized by persistent and progressive deterioration of glucose tolerance. Both insulin resistance and impaired insulin secretion contribute to development of Type 2 diabetes. However, whilst insulin resistance is fully apparent in the pre-diabetic condition, impairment of insulin secretion worsens over the time, being paralleled by a progressive decline in both pancreatic B-cell function and B-cell mass. Intense research has identified a number of genetic variants that may predispose to impaired B-cell function, but such predisposition can be precipitated and worsened by toxic effects of hyperglycaemia (glucotoxicity) and elevated levels of free fatty acids (lipotoxicity). All these aspects of the pathogenesis of Type 2 diabetes are discussed in this review. Moreover, treatments that target reduction in glucotoxicity or lipotoxicity are outlined, including emerging strategies that target the role of glucagon-like peptide 1 and sodium glucose co-transporter 2.

Familial renal glucosuria and SGLT2: from a mendelian trait to a therapeutic target

Four members of two glucose transporter families, SGLT1, SGLT2, GLUT1, and GLUT2, are differentially expressed in the kidney, and three of them have been shown to be necessary for normal glucose resorption from the glomerular filtrate. Mutations in SGLT1 are associated with glucose-galactose malabsorption, SGLT2 with familial renal glucosuria (FRG), and GLUT2 with Fanconi-Bickel syndrome. Patients with FRG have decreased renal tubular resorption of glucose from the urine in the absence of hyperglycemia and any other signs of tubular dysfunction. Glucosuria in these patients can range from <1 to >150 g/1.73 m(2) per d. The majority of patients do not seem to develop significant clinical problems over time, and further description of specific disease sequelae in these individuals is reviewed. SGLT2, a critical transporter in tubular glucose resorption, is located in the S1 segment of the proximal tubule, and, as such, recent attention has been given to SGLT2 inhibitors and their utility in patients with type 2 diabetes, who might benefit from the glucose-lowering effect of such compounds. A natural analogy is made of SGLT2 inhibition to observations with inactivating mutations of SGLT2 in patients with FRG, the hereditary condition that results in benign glucosuria. This review provides an overview of renal glucose transport physiology, FRG and its clinical course, and the potential of SGLT2 inhibition as a therapeutic target in type 2 diabetes.

A study of dapagliflozin in patients with type 2 diabetes receiving high doses of insulin plus insulin sensitizers: applicability of a novel insulin-independent treatment

OBJECTIVE

To determine whether dapagliflozin, which selectively inhibits renal glucose reabsorption, lowers hyperglycemia in patients with type 2 diabetes that is poorly controlled with high insulin doses plus oral antidiabetic agents (OADs).

RESEARCH DESIGN AND METHODS

This was a randomized, double-blind, three-arm parallel-group, placebo-controlled, 26-center trial (U.S. and Canada). Based on data from an insulin dose-adjustment setting cohort (n = 4), patients in the treatment cohort (n = 71) were randomly assigned 1:1:1 to placebo, 10 mg dapagliflozin, or 20 mg dapagliflozin, plus OAD(s) and 50% of their daily insulin dose. The primary outcome was change from baseline in A1C at week 12 (dapagliflozin vs. placebo, last observation carried forward [LOCF]).

RESULTS

At week 12 (LOCF), the 10- and 20-mg dapagliflozin groups demonstrated -0.70 and -0.78% mean differences in A1C change from baseline versus placebo. In both dapagliflozin groups, 65.2% of patients achieved a decrease from baseline in A1C > or =0.5% versus 15.8% in the placebo group. Mean changes from baseline in fasting plasma glucose (FPG) were +17.8, +2.4, and -9.6 mg/dl (placebo, 10 mg dapagliflozin, and 20 mg dapagliflozin, respectively). Postprandial glucose (PPG) reductions with dapagliflozin also showed dose dependence. Mean changes in total body weight were -1.9, -4.5, and -4.3 kg (placebo, 10 mg dapagliflozin, and 20 mg dapagliflozin). Overall, adverse events were balanced across all groups, although more genital infections occurred in the 20-mg dapagliflozin group than in the placebo group.

CONCLUSIONS

In patients receiving high insulin doses plus insulin sensitizers who had their baseline insulin reduced by 50%, dapagliflozin decreased A1C, produced better FPG and PPG levels, and lowered weight more than placebo.

Present and Prospective Pharmacotherapy for the Management of Patients with Type 2 Diabetes

Diabetes Mellitus is a chronic condition prevalent worldwide. Type 2 diabetes is the most common form of diabetes, comprising 90% to 95% of all cases. Over the last few decades, the importance of glycemic control and its impact on prevention of diabetes-related complications has been documented in multiple clinical trials. As most patients with type 2 diabetes will require pharmacologic intervention to achieve and maintain appropriate glycemic control, new medications targeting different aspects of the pathophysiology of type 2 diabetes have been a significant focus of research and development. During the last decade, multiple new medications for diabetes management have become available: these medications have novel mechanisms of action, differences in effectiveness, and varying side effect profiles which will be reviewed in this article. Some of these newer medications, such as the GLP-1 analogues and DPP-4 inhibitors, have become widely accepted as therapeutic options for the management of type 2 diabetes.Additional classes of glucose-lowering medications are expected to become available in the near future. This manuscript will summarize available data regarding these newer and prospective medications for the management of type 2 diabetes.

Long-term treatment with sergliflozin etabonate improves disturbed glucose metabolism in KK-A(y) mice

Sergliflozin etabonate, a novel oral selective low-affinity sodium glucose cotransporter (SGLT2) inhibitor, improves hyperglycemia by suppressing renal glucose reabsorption, in which SGLT2 participates as a dominant transporter. In the present study, we examined the antidiabetic profile of sergliflozin etabonate in a diabetic model, KK-A(y) mice, with symptoms of obesity and hyperinsulinemia. The blood glucose level was monitored in non-fasted female KK-A(y) mice after a single oral administration of sergliflozin etabonate. The non-fasting blood glucose level was reduced in a dose-dependent manner after a single oral administration of sergliflozin etabonate (39% reduction at 2 h after a dose of 30 mg/kg). The effects of long-term administration of sergliflozin etabonate on the blood glucose level were assessed in female KK-A(y) mice in several studies (4-day, 8-week, and 9-week administration study), in which sergliflozin etabonate was administered in the diet. The non-fasting blood glucose and plasma insulin were both lowered dose-dependently in the 4-day administration study. Long-term treatment with sergliflozin etabonate dose-dependently improved the hyperglycemia and prevented body weight gain in the 8-week study. In addition to the improvement in glycemic control, fatty liver and pancreatic beta-cell abnormalities were ameliorated in mice fed sergliflozin etabonate in the 9-week study. These data indicate that SGLT2 inhibitors could be useful to improve hyperglycemia resulting from insulin resistance without pancreatic beta-cell abuse or body weight gain. SGLT2 inhibitors may simultaneously realize both a systemic negative energy balance and correction of hyperglycemia.

Enantioselective synthesis of beta-(3-hydroxypyrazol-1-yl) ketones using an organocatalyzed Michael addition reaction

Beta-(3-hydroxypyrazol-1-yl) ketones have been prepared in high yields and excellent enantioselectivities (94-98% ee) via a Michael addition reaction between 2-pyrazolin-5-ones and aliphatic acyclic alpha,beta-unsaturated ketones using 9-epi-9-amino-9-deoxyquinine as the catalyst. These results account for the first example of an aza-Michael addition of the ambident 2-pyrazolin-5-one anion to a Michael acceptor.

Glucose toxicity: the leading actor in the pathogenesis and clinical history of type 2 diabetes - mechanisms and potentials for treatment

AIM

Although it is now well established that the deleterious effects of chronic hyperglycaemia (i.e., glucose toxicity) play an important role in the progressive impairment of insulin secretion and sensitivity, the two major actors of the pathogenesis of type 2 diabetes mellitus, the precise biochemical and molecular mechanisms responsible for the defects induced by glucose toxicity still remain to be defined.

DATA SYNTHESIS

here we will briefly report on convincing evidence that glucose toxicity acts through oxidative stress, modifications in the exosamine pathway, protein kinase C and others. After inducing or contributing to the genesis of type 2 diabetes, these same mechanisms are considered responsible for the appearance and worsening of diabetic specific microvascular complications, while its role in increasing the risk of cardiovascular diseases is less clear. Recent intervention studies (ADVANCE, ACCORD, VADT), conducted to evaluate the effects of strict glycaemic control, apparently failed to demonstrate an effect of glucose toxicity on cardiovascular diseases, at least in secondary prevention or when diabetes is present for a prolonged time. The re-examination, 20 years later, of the population studied in the UKPDS study, however, clearly demonstrated that the earliest is the strict glycaemic control reached, the lowest is the incidence of cardiovascular diseases observed, including myocardial infarction.

CONCLUSION

The acquaintance of the role of glucose toxicity should strongly influence the usual therapeutic choices and glycaemic targets where the reduced or absent risk of hypoglycaemia, durability of action, and data on prolonged safety should be the preferred characteristics of the drug of choice in the treatment of type 2 diabetes mellitus.

Sodium-glucose co-transporter-2 inhibitors: an emerging new class of oral antidiabetic drug

The sodium-glucose co-transporter-2 (SGLT2) is a low-affinity transport system that is specifically expressed in the kidney and plays an important role in renal glucose reabsorption in the proximal tubule. Competitive inhibition of SGLT2 therefore represents an innovative therapeutic strategy for the treatment of hyperglycaemia and/or obesity in patients with type 1 or type 2 diabetes by enhancing glucose and energy loss through the urine. The observation that individuals with familial renal glycosuria maintain normal long-term kidney function provides some reassurance that this mode of action will not adversely affect renal function. Intense research in this therapeutic area has led to the discovery of novel SGLT2 inhibitors, each with different chemical, pharmacodynamic and pharmacokinetic profiles. This review outlines the biology, expression and pleotropic activity of the SGLT system and the pharmacological profile of SGLT2 inhibitors and provides a summary of preclinical and limited clinical data available to characterize the efficacy, safety and potential clinical utility of SGLT2 inhibitors in the management of diabetes.