JTP-109192, a novel G protein-coupled receptor 119 agonist, prevents atherosclerosis by improving hypercholesterolaemia in congenic spontaneously hyperlipidaemic mice.

G protein-coupled receptor 119 (GPR119) expression in pancreatic ß-cells and intestinal L-cells is a potential therapeutic target for the treatment of type 2 diabetes. Previously, we have reported that the GPR119 agonist JTP-109192 improves glucose metabolism with single and repeated administration. Conversely, overexpression of the Gpr119 gene reportedly regulates cholesterol transporter expression in animal models, and a natural GPR119 agonist, oleoylethanolamide (OEA), improves atherosclerosis. Therefore, improving dyslipidaemia is considered a possible feature of GPR119 agonists. In the present study, the lipid-lowering effect of JTP-109192 was examined in BALB/c background spontaneously hyperlipidaemic (SHL) mice with repeated administration, once daily for 12 weeks. On repeated administration, JTP-109192 revealed a cholesterol-lowering effect and improved atherosclerosis following histopathological examination. With further investigation, the cholesterol-lowering effect and subsequent antiatherosclerotic effect of JTP-109192 was attributed to changes in intestinal cholesterol metabolism gene expression. Based on these results, JTP-109192 represents a new potential antihypercholesterolaemic agent for the treatment of dyslipidaemia.

Analysis of haemodynamics and angiogenic response to ischaemia in the obese type 2 diabetic model Spontaneously Diabetic Torii Leprfa (SDT fatty) rats.

Peripheral artery disease (PAD) is defined as peripheral blood flow impairment, especially in the legs, caused by atherosclerotic stenosis. The disease decreases quality of life because of intermittent claudication or necrosis of the leg. The hindlimb ischaemia model, in which ischaemia is induced by femoral artery ligation, is often utilized as a PAD model. In the hindlimb ischaemia model, nonmetabolic syndrome animals are mainly used. In this study, we investigated the usefulness of Spontaneously Diabetic Torii Leprfa (SDT fatty) rats, a new model for obese type 2 diabetes, as a new PAD animal model. We found that hindlimb blood flow in SDT fatty rats was significantly lower than that in Sprague-Dawley (SD) rats under nonischaemic conditions. Furthermore, SDT fatty rats showed a significantly higher plasma nitrogen oxide level, shorter prothrombin time, and shorter activated partial thromboplastin time than SD rats. In addition, we found that the change in blood flow 7 days after induction of hindlimb ischaemia and the number of Von Willebrand factor-positive vessels in gastrocnemius muscles were significantly lower in SDT fatty rats than in SD rats. These results suggest that excess production of reactive oxygen species and coagulation activation could be involved in lower blood flow in non-ischaemic rats and that decreased angiogenesis could be involved in the poor recovery of blood flow in SDT fatty rats with hindlimb ischaemia. Taken together, our results suggest that SDT fatty rats might be useful as a new model for PAD with metabolic syndrome.

A Novel TNF-α Converting Enzyme (TACE) Selective Inhibitor JTP-96193 Prevents Insulin Resistance in KK-Ay Type 2 Diabetic Mice and Diabetic Peripheral Neuropathy in Type 1 Diabetic Mice.

Tumor necrosis factor-α (TNF-α) converting enzyme/a disintegrin and metalloproteinase domain-containing protein 17 (TACE/ADAM17) is a key sheddase that releases TNF-α from its inactive precursor and is thought as a new drug target to inhibit TNF-α production. In the present study, pharmacological effects of a novel TACE selective inhibitor, JTP-96193, on type 2 diabetes and diabetic peripheral neuropathy (DPN) as its major complication was examined. Enzyme inhibitory activity of JTP-96193 on TACE and other ADAMs was measured in in vitro. High fat-induced obese mice and type 2 diabetic KK-Ay mice were used to evaluate the effect of JTP-96193 on insulin resistance. Finally, streptozotocin (STZ)-induced diabetic mice were treated with JTP-96193 to evaluate the sciatic motor nerve conduction velocities (MNCV). JTP-96193 selectively inhibited human TACE activity with IC50 value of 5.4 nM and showed more than 1800-fold selectivity against other matrix metalloproteinases. In mouse models of obesity and diabetes, JTP-96193 reduced the TNF-α release from the fat tissue and prevented development of diabetes and improved insulin resistance, respectively. Furthermore, JTP-96193 prevented delay of sciatic MNCV without any effects on blood glucose or insulin levels in STZ-induced diabetic mice. TACE inhibitor is effective on insulin resistance and DPN independent from glucose-lowering effect. These pharmacological properties of JTP-96193 may be helpful to treat type 2 diabetes accompanied by its microvascular complications.

Chronic treatment of JTP-109192, a novel G-protein coupled receptor 119 agonist, improves metabolic abnormalities in Zucker Fatty rats.

G-protein coupled receptor 119 (GPR119) expression in pancreatic ß-cells and intestinal L cells is a potential therapeutic target for treating type 2 diabetes. A natural GPR119 agonist oleoylethanolamide is well known to enhance a glucose-stimulated insulin secretion (GSIS) and glucagon-like peptide-1 (GLP-1) secretion by elevating intracellular cAMP levels. In the present study, a glucose lowering effect of the GPR119 agonist, JTP-109192 leading to improvement of insulin sensitivity was examined in Zucker Fatty (ZF) rats. We investigated the in vitro effects of JTP-109192 on GSIS in the rat pancreatic ß-cell line (INS1E) cells and on GLP-1 secretion in the murine enteroendocrine cell line (GLUTag) cells. We also investigated the effect of JTP-109192 on GSIS in Sprague-Dawley (SD) rats with single administration and its effect on glucose metabolism in ZF rats with repeated administration once daily for about 6 weeks. After repeated administration, the hyperinsulinaemic euglycaemic glucose clamp test was performed to evaluate insulin sensitivity. JTP-109192 increased intracellular cAMP levels (EC50 value: 3.6 nmol/L) and enhanced GSIS in the INS1E cells and GLP-1 secretion in GLUTag cells. In SD rats, a single administration of JTP-109192 enhanced GSIS at high blood glucose levels. The repeated administrations in ZF rats improved glucose metabolism without lack of drug efficacy (tachyphylaxis) and increased glucose infusion rates due to improvement of insulin sensitivity.

Pathophysiological profiles of SDT fatty rats, a potential new diabetic peripheral neuropathy model.

INTRODUCTION: To establish an animal model for diabetic peripheral neuropathy (DPN) at an earlier stage, we performed functional and pathophysiological evaluations in Spontaneously Diabetic Torii (SDT) fatty rats before 16weeks of age. METHODS: Male SDT fatty rats were treated with vehicle or phlorizin (100 to 150mg/kg/day) from 5 to 16weeks. Sprague-Dawley (SD) rats were used as age-matched controls. Body weights and biochemical parameters were measured over time. During the treatment period, the sensory and motor nerve conduction velocity (SNCV and MNCV) of the sciatic nerve, blood pressure, pupil size, and electrocardiograms were measured. At 16weeks, the rats were sacrificed and sural nerves and intraepidermal nerves were sampled for histological studies, electron microscopic analysis and assessments of nerve fiber density. RESULTS: Functional abnormalities, such as delays of SNCV, increase of blood pressure, reduced pupillary reactivity, and decrease of the coefficient of variance of R-R intervals were observed in SDT fatty rats. Histopathologically, decreased intraepidermal nerve fiber density, mitochondrial abnormalities of small myelinated fibers, and vacuolation and mitochondrial swelling of unmyelinated fibers were found in SDT fatty rats. These changes were prevented by well-controlled blood glucose with phlorizin treatment. DISCUSSION: Male SDT fatty rats can help future work on DPN in diabetes with obesity, since this rat exhibited functional and pathological abnormalities in somatic and autonomic nerve from an early stage of diabetes.

Assessment of Pharmacological Responses to an Anti-diabetic Drug in a New Obese Type 2 Diabetic Rat Model.

INTRODUCTION: The number of diabetic patients has recently been increasing worldwide, and numerous anti-diabetic drugs have been developed to induce good glycemic control. In particular, metformin, which exhibits glucose-lowering effects by suppressing gluconeogenesis in the liver, is widely used as a first line oral anti-diabetic drug for type 2 diabetes mellitus. MATERIAL AND METHODS: In this study, the pharmacological effects of metformin were investigated using female and male Spontaneously Diabetic Torii (SDT) fatty rats, a new obese type 2 diabetic model. RESULTS: Two experiments were performed: an assessment of repeated treatment with metformin in female SDT fatty rats 5 to 13 weeks of age (experiment 1), and an assessment of repeated treatment with metformin in male SDT fatty rats 6 to 10 weeks of age (experiment 2). In female SDT fatty rats, metformin treatment led to good glycemic control, increases in sensory nerve conduction velocity, and improvements in pancreatic abnormalities such as irregular boundaries and vacuole form of islets. In male SDT fatty rats, metformin decreased blood glucose levels 4 weeks after treatment. CONCLUSION: Metformin treatment led to maintained good glycemic control and improved neuropathy and pancreatic lesions in female SDT fatty rats. The SDT fatty rat is useful for the development of novel anti-diabetic agents that show potential to improve glucose metabolic disorders in the liver.

Intrajejunal infusion of 2-monoacylglycerol reduced food intake without inducing diarrhea in rats.

Some nutrients, such as carbohydrate, fat and protein, are known to stimulate satiety. However, the effect of sn-2-monoacylglycerol (2-MG), one of the digestive products of triglycerides, on food intake is still unclear. In the present study, the effects of 2-MG on food intake and diarrhea were evaluated and compared with long-chain fatty acid (LCFA) in rats by intrajejunal infusion. Intrajejunal infusion of 2-MG reduced food intake. In addition, 2-MG did not induce diarrhea at the condition that it comparably reduced food intake as compared with LCFA. These results suggest that 2-MG stimulates satiety without inducing diarrhea, different from LCFA.

JTP-103237, a monoacylglycerol acyltransferase inhibitor, prevents fatty liver and suppresses both triglyceride synthesis and de novo lipogenesis.

AIM: Monoacyglycerol acyltransferases (MGATs) are known to play important roles in intestinal TG absorption. In contrast, the role of MGATs in the liver is still unclear. We investigated the effects of JTP-103237, a novel MGAT inhibitor, on hepatic MGAT activity and hepatic lipid metabolism. RESULTS: JTP-103237 reduced hepatic triglyceride content and hepatic MGAT activity in a high sucrose very low fat (HSVLF) diet induced fatty liver model. Interestingly, JTP-103237 suppressed not only triglyceride (TG) and diacylglycerol (DG) synthesis, but also fatty acid (FA) synthesis (de novo lipogenesis) in this model. JTP-103237 also suppressed lipogenesis-related gene expression, such as sterol regulatory element-binding protein 1-c. Moreover, JTP-103237 decreased plasma glucose levels and total cholesterol and reduced the accumulation of epididymal fats in HSVLF diet fed mice. CONCLUSION: In the present study, JTP-103237 prevented carbohydrate-induced fatty liver and suppressed both TG synthesis and de novo lipogenesis, suggesting MGAT inhibitor may prevent carbohydrate-induced metabolic disorders, including NAFLD, obesity and diabetes.

JTP-103237, a novel monoacylglycerol acyltransferase inhibitor, modulates fat absorption and prevents diet-induced obesity.

Monoacylglycerol acyltransferase 2 (MGAT2) plays an important role in intestinal fat absorption. We discovered the novel MGAT2 inhibitor, JTP-103237, and evaluated its pharmacological profile. JTP-103237 selectively inhibited MGAT2 without remarkable species differences and reduced absorbed lipids in circulation. After lipid administration, JTP-103237 slightly but significantly decreased triglyceride content in proximal small intestine and significantly increased the lipids content in the distal small intestine. In addition, JTP-103237 significantly increased MGAT substrate (monoacylglycerol and fatty acid) content in the small intestine. JTP-103237 increased plasma peptide YY levels after lipid loading and reduced food intake in a dietary fat-dependent manner. After chronic treatment, JTP-103237 significantly decreased body weight and increased O2 consumption in the early dark phase in high fat diet induced obese (DIO) mice. Moreover, JTP-103237 improved glucose tolerance and decreased fat weight and hepatic triglyceride content in DIO mice. Our findings indicate that JTP-103237 prevents diet-induced obesity by inhibiting intestinal MGAT2 and has unique properties as a drug for the treatment of obesity.

Contribution of hyperglycemia on diabetic complications in obese type 2 diabetic SDT fatty rats: effects of SGLT inhibitor phlorizin.

The spontaneously diabetic torii (SDT) fatty rat is a new model of type 2 diabetes showing overt obesity, hyperglycemia and hyperlipidemia. With early onset of diabetes mellitus, diabetic microvascular complications, including nephropathy, peripheral neuropathy and retinopathy, are observed at young ages. In the present study, blood glucose levels of female SDT fatty rats were controlled with phlorizin, a non-selective SGLT inhibitor, to examine whether and how these complications are caused by hyperglycemia. Phlorizin treatment adequately controlled plasma glucose levels during the experiment. At 29 weeks of age, urinary albumin excretion considerably increased in SDT fatty rats. Glomerulosclerosis and tubular pathological findings also indicate diabetic nephropathy. These renal parameters tended to decrease with phlorizin; however, effects were partial. Sciatic nerve conduction velocities were significantly delayed in SDT fatty rats compared with Sprague-Dawley (SD) rats. Intraepidermal nerve fiber density, an indicator of subclinical small nerve fiber neuropathy, significantly decreased in SDT fatty rats. Retinal dysfunction (prolongation of peak latency for oscillatory potential in electroretinograms) and histopathological eye abnormalities, including retinal folding and mature cataracts were also observed. Both nerve and eye disorders were prevented with phlorizin. These findings indicate that severe hyperglycemia mainly causes diabetic complications in SDT fatty rats. However, other factors, such as hyperlipidemia and hypertension, may affect diabetic nephropathy. These characteristics of diabetic complications will become helpful in evaluating new drugs for diabetic complications using SDT fatty rats.

Diabetic peripheral neuropathy in Spontaneously Diabetic Torii-Lepr(fa) (SDT fatty) rats.

Spontaneously Diabetic Torii (SDT) rat is a hereditary model of diabetes. Although the SDT rat shows severe diabetic complications, the onset of hyperglycemia is late. SDT fatty rat, established by introducing the fa allele of the Zucker fatty rat to SDT rat, develops diabetes much faster than SDT rat. In the present study, diabetic peripheral neuropathy (DPN) was evaluated to show the further usefulness of this animal model. Motor nerve conduction velocity (MNCV) was delayed, and the number of sural nerve fibers was decreased in SDT fatty rat. Treatment of pioglitazone lowered blood glucose level and prevented delay of MNCV in SDT fatty rats. SDT fatty rat is a useful animal model for studies of DPN in type 2 diabetes.

JTT-130, a novel intestine-specific inhibitor of microsomal triglyceride transfer protein, suppresses food intake and gastric emptying with the elevation of plasma peptide YY and glucagon-like peptide-1 in a dietary fat-dependent manner.

The microsomal triglyceride transfer protein (MTP) takes part in the mobilization and secretion of triglyceride-rich lipoproteins from enterocytes and hepatocytes. In this study, we investigated the effects of diethyl-2-({3-dimethylcarbamoyl-4-[(4'-trifluoromethylbiphenyl-2-carbonyl) amino] phenyl}acetyloxymethyl)-2-phenylmalonate (JTT-130), a novel intestine-specific MTP inhibitor, on food intake, gastric emptying, and gut peptides using Sprague-Dawley rats fed 3.1% fat, 13% fat, or 35% fat diets. JTT-130 treatment suppressed cumulative food intake and gastric emptying in rats fed a 35% fat diet, but not a 3.1% fat diet. In rats fed a 13% fat diet, JTT-130 treatment decreased cumulative food intake but not gastric emptying. In addition, treatment with orlistat, a lipase inhibitor, completely abolished the reduction of food intake and gastric emptying by JTT-130 in rats fed a 35% fat diet. On the other hand, JTT-130 treatment increased the plasma concentrations of gut peptides, peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) but not cholecystokinin, in the portal vein in rats fed a 35% fat diet. These elevations in PYY and GLP-1 were also abolished by treatment with orlistat. Furthermore, JTT-130 treatment in rats fed a 35% fat diet increased the contents of triglycerides and free fatty acids in the intestinal lumen, which might contribute to the elevation of PYY and GLP-1 levels. The present findings indicate that JTT-130 causes satiety responses, decreased food intake, and gastric emptying in a dietary fat-dependent manner, with enhanced production of gut peptides such as PYY and GLP-1 from the intestine.