Toshiyuki Takasu

Effect of (R)-2-(2-Aminothiazol-4-yl)-4′-{2-[(2-hydroxy-2-phenylethyl)amino]ethyl} Acetanilide (YM178), a Novel Selective β3-Adrenoceptor Agonist, on Bladder Function

We evaluated the pharmacological characteristics of (R)-2-(2-aminothiazol-4-yl)-4′-{2-[(2-hydroxy-2-phenylethyl)amino]-ethyl} acetanilide (YM178). YM178 increased cyclic AMP accumulation in Chinese hamster ovary (CHO) cells expressing human β3-adrenoceptor (AR). The half-maximal effective concentration (EC50) value was 22.4 nM. EC50 values of YM178 for human β1- and β2-ARs were 10,000 nM or more, respectively. The ratio of intrinsic activities of YM178 versus maximal response induced by isoproterenol (nonselective β-AR agonist) was 0.8 for human β3-ARs, 0.1 for human β1-ARs, and 0.1 for human β2-ARs. The relaxant effects of YM178 were evaluated in rats and humans bladder strips precontracted with carbachol (CCh) and compared with those of isoproterenol and 4-[3-[(1,1-dimethylethyl)amino]-2-hydroxypropoxy]-1,3-dihydro-2H-benzimidazol-2-one hydrochloride (CGP-12177A) (β3-AR agonist). EC50 values of YM178 and isoproterenol in rat bladder strips precontracted with 10–6 M CCh were 5.1 and 1.4 μM, respectively, whereas those in human bladder strips precontracted with 10–7 M CCh were 0.78 and 0.28 μM, respectively. In in vivo study, YM178 at a dose of 3 mg/kg i.v. decreased the frequency of rhythmic bladder contraction induced by intravesical filling with saline without suppressing its amplitude in anesthetized rats. These findings suggest the suitability of YM178 as a therapeutic drug for the treatment of symptoms of overactive bladder such as urinary frequency, urgency, and urge incontinence.

Effect of YM178, a Novel Selective β3-Adrenoceptor Agonist, on Bladder Function

We evaluated the pharmacological characteristics of (R)-2-(2-aminothiazol-4-yl)-4′-{2-[(2-hydroxy-2-phenylethyl)amino]-ethyl} acetanilide (YM178). YM178 increased cyclic AMP accumulation in Chinese hamster ovary (CHO) cells expressing human β3-adrenoceptor (AR). The half-maximal effective concentration (EC50) value was 22.4 nM. EC50 values of YM178 for human β1- and β2-ARs were 10,000 nM or more, respectively. The ratio of intrinsic activities of YM178 versus maximal response induced by isoproterenol (nonselective β-AR agonist) was 0.8 for human β3-ARs, 0.1 for human β1-ARs, and 0.1 for human β2-ARs. The relaxant effects of YM178 were evaluated in rats and humans bladder strips precontracted with carbachol (CCh) and compared with those of isoproterenol and 4-[3-[(1,1-dimethylethyl)amino]-2-hydroxypropoxy]-1,3-dihydro-2H-benzimidazol-2-one hydrochloride (CGP-12177A) (β3-AR agonist). EC50 values of YM178 and isoproterenol in rat bladder strips precontracted with 10–6 M CCh were 5.1 and 1.4 μM, respectively, whereas those in human bladder strips precontracted with 10–7 M CCh were 0.78 and 0.28 μM, respectively. In in vivo study, YM178 at a dose of 3 mg/kg i.v. decreased the frequency of rhythmic bladder contraction induced by intravesical filling with saline without suppressing its amplitude in anesthetized rats. These findings suggest the suitability of YM178 as a therapeutic drug for the treatment of symptoms of overactive bladder such as urinary frequency, urgency, and urge incontinence.

Effects of SGLT2 selective inhibitor ipragliflozin on hyperglycemia, hyperlipidemia, hepatic steatosis, oxidative stress, inflammation, and obesity in type 2 diabetic mice

The sodium-glucose cotransporter 2 (SGLT2) is responsible for most glucose reabsorption in the kidney and has been proposed as a novel therapeutic target for the treatment of type 2 diabetes. In the present study, the therapeutic effects of SGLT2 selective inhibitor ipragliflozin were examined in high-fat diet and streptozotocin-nicotinamide-induced type 2 diabetic mice which exhibit impaired insulin secretion, insulin resistance, hyperlipidemia, hepatic steatosis, and obesity. Single administration of ipragliflozin dose-dependently increased urinary glucose excretion, reduced blood glucose and plasma insulin levels, and improved glucose intolerance. Four-week repeated administration of ipragliflozin improved not only glucose tolerance, hyperglycemia, and hyperinsulinemia but also impaired insulin secretion, hyperlipidemia, hepatic steatosis, and obesity with a concomitant increase in urinary glucose excretion. In addition, ipragliflozin reduced plasma and liver levels of oxidative stress biomarkers (thiobarbituric acid reactive substances and protein carbonyl) and inflammatory markers (interleukin 6, tumor necrosis factor α, monocyte chemotactic protein-1, and c-reactive protein), and improved liver injury as assessed by plasma levels of aminotransferases. These results demonstrate that SGLT2 selective inhibitor ipragliflozin improves not only hyperglycemia but also diabetes/obesity-associated metabolic abnormalities in type 2 diabetic mice and suggest that ipragliflozin may be useful in treating type 2 diabetes with metabolic syndrome.

SGLT2 selective inhibitor ipragliflozin reduces body fat mass by increasing fatty acid oxidation in high-fat diet-induced obese rats

Ipragliflozin is a novel and selective sodium-glucose cotransporter 2 (SGLT2) inhibitor that induces sustained increases in urinary glucose excretion by inhibiting renal glucose reabsorption and thereby exerting a subsequent antihyperglycemic effect. Here, we examined the effect of ipragliflozin on body weight in high-fat diet-induced (HFD) obese rats. Treatment of ipragliflozin (10mg/kg once daily) reduced body weight despite a slight increase in food intake. Dual-energy X-ray absorptiometry and computed tomography demonstrated that the reduction in body weight was accompanied by reduced visceral and subcutaneous fat masses but not lean mass or bone mineral content. Analysis of plasma and urinary parameters suggested the possibility that ipragliflozin enhanced lipolysis and fatty acid oxidation, and indirect calorimetry showed that ipragliflozin decreased the heat production rate from glucose but increased the rate from fat and lowered the respiratory exchange ratio. In conclusion, these data demonstrate that ipragliflozin-induced urinary glucose excretion specifically reduces fat mass with steady calorie loss by promoting the use of fatty acids instead of glucose as an energy source in HFD rats. By improving hyperglycemia and promoting weight reduction, ipragliflozin may prove useful in treating type 2 diabetes in obese individuals.

Effects of sodium-glucose cotransporter 2 selective inhibitor ipragliflozin on hyperglycaemia, oxidative stress, inflammation and liver injury in streptozotocin-induced type 1 diabetic rats.

Sodium‐glucose cotransporter (SGLT) 2 plays an important role in renal glucose reabsorption and has been highlighted as a therapeutic target for the treatment of diabetes. Here, we investigated the therapeutic effects of SGLT2 selective inhibitor ipragliflozin in type 1 diabetic rats.

Ipragliflozin, an SGLT2 inhibitor, exhibits a prophylactic effect on hepatic steatosis and fibrosis induced by choline-deficient l-amino acid-defined diet in rats

Ipragliflozin is a selective sodium glucose cotransporter 2 (SGLT2) inhibitor that increases urinary glucose excretion by inhibiting renal glucose reabsorption and thereby causes a subsequent antihyperglycemic effect. As nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), is closely linked to metabolic diseases such as obesity and diabetes, we investigated the effect of ipragliflozin on NAFLD in rats fed a choline-deficient l-amino acid-defined (CDAA) diet. Five weeks after starting the CDAA diet, rats exhibited hepatic triglyceride (TG) accumulation, fibrosis, and mild inflammation. Repeated oral administration of ipragliflozin (3mg/g, once daily for 5 weeks) prevented both hepatic TG accumulation (188 vs.290 mg/g tissue vehicle-treated group; P<0.001) and large lipid droplet formation. Further, ipragliflozin exerted a prophylactic effect on liver fibrosis, as indicated by a marked decrease in hydroxyproline content and fibrosis score. Pioglitazone, which is known to be effective on hepatic fibrosis in CDAA diet-fed rats as well as NASH patients with type 2 diabetes mellitus (T2DM), also exerted a mild prophylactic effect on fibrosis, but not on hepatic TG accumulation or inflammation. In conclusion, ipragliflozin prevented hepatic TG accumulation and fibrosis in CDAA-diet rats. These findings suggest the therapeutic potential of ipragliflozin for patients with NAFLD.

Characterization and comparison of sodium-glucose cotransporter 2 inhibitors in pharmacokinetics, pharmacodynamics, and pharmacologic effects.

The sodium-glucose cotransporter (SGLT) 2 offer a novel approach to treating type 2 diabetes by reducing hyperglycaemia via increased urinary glucose excretion. In the present study, the pharmacokinetic, pharmacodynamic, and pharmacologic properties of all six SGLT2 inhibitors commercially available in Japan were investigated and compared. Based on findings in normal and diabetic mice, the six drugs were classified into two categories, long-acting: ipragliflozin and dapagliflozin, and intermediate-acting: tofogliflozin, canagliflozin, empagliflozin, and luseogliflozin. Long-acting SGLT2 inhibitors exerted an antihyperglycemic effect with lower variability of blood glucose level via a long-lasting increase in urinary glucose excretion. In addition, ipragliflozin and luseogliflozin exhibited superiority over the others with respect to fast onset of pharmacological effect. Duration and onset of the pharmacologic effects seemed to be closely correlated with the pharmacokinetic properties of each SGLT2 inhibitor, particularly with respect to high distribution and long retention in the target organ, the kidney. While all six SGLT2 inhibitors were significantly effective in increasing urinary glucose excretion and reducing hyperglycemia, our findings suggest that variation in the quality of daily blood glucose control associated with duration and onset of pharmacologic effects of each SGLT2 inhibitor might cause slight differences in rates of improvement in type 2 diabetes.

Atorvastatin increases hepatic fatty acid beta-oxidation in sucrose-fed rats: comparison with an MTP inhibitor

We investigated the effects of atorvastatin, a widely used 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, and BMS-201038, a microsomal triglyceride transfer protein (MTP) inhibitor, in sucrose-fed hypertriglyceridemic rats to determine whether the activation of beta-oxidation by these compounds plays a role in their hypotriglyceridemic effect. The decrease in plasma triglyceride concentration and post-Triton very low-density lipoprotein (VLDL) triglyceride concentration, a measure of hepatic triglyceride secretion, by atorvastatin (30 mg/kg p.o.) for 2 weeks was to approximately the same degree as those by BMS-201038 (0.3 mg/kg). Atorvastatin (30 mg/kg) increased hepatic beta-oxidation activity by 54% (P < 0.01), while BMS-201038 (0.3 mg/kg) had no significant effect. Atorvastatin decreased hepatic triglyceride, fatty acid and cholesteryl ester concentrations by 21% to 39%, whereas BMS-201038 increased these variables by 28% to 307%. In the atorvastatin-treated groups, a significant relationship was seen not only between hepatic beta-oxidation activity and hepatic triglyceride concentration (R(2) = 0.535, P < 0.01), but also between hepatic and plasma triglyceride concentrations (R(2) = 0.586, P < 0.01). No effect of atorvastatin on hepatic fatty acid synthesis was observed. These results indicate that the activation of hepatic beta-oxidation by atorvastatin may contribute to the decrease in hepatic triglyceride concentration, leading to its hypotriglyceridemic effect.

Effect of ipragliflozin, an SGLT2 inhibitor, on progression of diabetic microvascular complications in spontaneously diabetic Torii fatty rats ☆

AIMS We investigated the effect of the selective sodium-dependent glucose cotransporter 2 inhibitor ipragliflozin on the simultaneous progression of diabetic microvascular complications of retinopathy, nephropathy and neuropathy in individual Spontaneously Diabetic Torii (SDT) fatty rats. MAIN METHODS Ipragliflozin was administered to male SDT fatty rats for 12weeks. Male Sprague-Dawley rats of the same age were used as non-diabetic controls. Non-fasting plasma glucose and glycated hemoglobin levels were measured every 4weeks. Cataract formation was monitored once a week, and the electroretinogram was measured after 6weeks of treatment. After the treatment period, motor nerve conduction velocity was measured and urinalysis was conducted. Tissue samples were then dissected for histopathological examination. KEY FINDINGS Treatment with ipragliflozin reduced glycated hemoglobin levels, inhibited the progression of cataract formation, prevented the prolongation of oscillatory potential peaks in the electroretinogram, ameliorated the slowing of motor nerve conduction velocity, and reduced the severity of glomerulosclerosis in SDT fatty rats. SIGNIFICANCE These results suggest that the control of hyperglycemia with ipragliflozin slows the progression of the diabetic complications of retinopathy, nephropathy, and neuropathy.

Discovery of novel thiourea derivatives as potent and selective β3-adrenergic receptor agonists

In the search for potent and selective human beta3-adrenergic receptor (AR) agonists as potential drugs for the treatment of obesity and noninsulin-dependent (type II) diabetes, we prepared a novel series of phenoxypropanolamine derivatives containing the thiourea moiety and evaluated their biological activities at human beta3-, beta2-, and beta1-ARs. Among these compounds, 4-nitrophenylthiourea (18i) and 3-methoxyphenylthiourea (18k) derivatives were found to exhibit potent agonistic activity at the beta3-AR, with EC(50) values of 0.10 and 0.16 microM, respectively, and no agonistic activity for either the beta1- or beta2-AR. In addition, they showed significant hypoglycemic activity in a rodent diabetic model.