Tofogliflozin long-term effects on atherosclerosis progression and major clinical parameters in patients with type 2 diabetes mellitus lacking a history of cardiovascular disease: a 2-year extension study of the UTOPIA trial.

BACKGROUND: This study aimed to assess the long-term effects of tofogliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, on atherosclerosis progression and major clinical parameters in patients with type 2 diabetes lacking an apparent history of cardiovascular disease. METHODS: This was a prospective observational 2-year extension study of the "Using TOfogliflozin for Possible better Intervention against Atherosclerosis for type 2 diabetes patients (UTOPIA)" trial, a 2-year randomized intervention study. The primary endpoints represented changes in the carotid intima-media thickness (IMT). Secondary endpoints included brachial-ankle pulse wave velocity (baPWV) and biomarkers for glucose metabolism, lipid metabolism, renal function, and cardiovascular risks. RESULTS: The mean IMT of the common carotid artery (IMT-CCA) significantly decreased in both the tofogliflozin (- 0.067 mm, standard error 0.009, p < 0.001) and conventional treatment groups (- 0.080 mm, SE 0.009, p < 0.001) throughout the follow-up period; however, no significant intergroup differences in the changes (0.013 mm, 95% confidence interval (CI) - 0.012 to 0.037, p = 0.32) were observed in a mixed-effects model for repeated measures. baPWV significantly increased in the conventional treatment group (82.7 ± 210.3 cm/s, p = 0.008) but not in the tofogliflozin group (- 17.5 ± 221.3 cm/s, p = 0.54), resulting in a significant intergroup difference in changes (- 100.2 cm/s, 95% CI - 182.8 to - 17.5, p = 0.018). Compared to the conventional treatment group, tofogliflozin significantly improved the hemoglobin A1c and high-density lipoprotein cholesterol levels, body mass index, abdominal circumference, and systolic blood pressure. The frequencies of total and serious adverse events did not vary significantly between the groups. CONCLUSIONS: Tofogliflozin was not associated with improved inhibition of carotid wall thickening but exerted long-term positive effects on various cardiovascular risk factors and baPWV while showing a good safety profile.

The Influence of Tofogliflozin on Treatment-Related Quality of Life in Patients with Type 2 Diabetes Mellitus.

INTRODUCTION: Treatment-related quality of life (QOL) is an important aspect of diabetes management. We evaluated the influence of a sodium-glucose cotransporter 2 (SGLT2) inhibitor, tofogliflozin, on treatment-related QOL in Japanese patients with type 2 diabetes mellitus (T2DM). METHODS: This is the prespecified subanalysis study of the "Using TOfogliflozin for Possible better Intervention against Atherosclerosis for type 2 diabetes patients (UTOPIA)" trial. Treatment-related QOL was evaluated at baseline, week 26, week 52, and week 104 after the initiation of the study using the Diabetes Therapy-Related QOL questionnaire (DTR-QOL). Among the 340 patients in the original UTOPIA study, a total of 252 patients (127, tofogliflozin group; 125, conventional treatment group) who completed the DTR-QOL questionnaire at baseline were the study subjects of the current subanalysis. RESULTS: The tofogliflozin and conventional treatment groups exhibited almost comparable baseline clinical characteristics, while the use of antihypertensive drugs and lipid-lowering agents was significantly lower in the tofogliflozin treatment group than in the conventional treatment group. Tofogliflozin treatment increased the total score of DTR-QOL7 from baseline (P < 0.001), while conventional treatment did not change it. There were statistically significant differences in delta change in the total DTR-QOL7 score and DTR-QOL7 Q4, Q5, Q6, and Q7 scores from the baseline to week 104 between the treatment groups. Delta changes in HbA1c (Spearman's correlation coefficient, ρ = - 0.30, P < 0.001), fasting blood glucose (ρ = - 0.16, P = 0.031), BMI (ρ = - 0.19, P = 0.008), and waist circumference (ρ = - 0.17, P = 0.024) at week 104 were negatively associated with delta change in the total QOL7 score. CONCLUSIONS: Our data indicated that tofogliflozin treatment improved treatment-related QOL compared to conventional treatment in Japanese patients with T2DM, in accordance with the improvement of major cardiovascular risk factors. TRIAL REGISTRATION: UMIN000017607.

Effect of tofogliflozin on arterial stiffness in patients with type 2 diabetes: prespecified sub-analysis of the prospective, randomized, open-label, parallel-group comparative UTOPIA trial.

BACKGROUND: Tofogliflozin, an SGLT2 inhibitor, is associated with favorable metabolic effects, including improved glycemic control and serum lipid profile and decreased body weight, visceral adipose tissue, and blood pressure (BP). This study evaluated the effects of tofogliflozin on the brachial-ankle pulse wave velocity (baPWV) in patients with type 2 diabetes (T2DM) without a history of apparent cardiovascular disease. METHODS: The using tofogliflozin for possible better intervention against atherosclerosis for type 2 diabetes patients (UTOPIA) trial is a prospective, randomized, open-label, multicenter, parallel-group, comparative study. As one of the prespecified secondary outcomes, changes in baPWV over 104 weeks were evaluated in 154 individuals (80 in the tofogliflozin group and 74 in the conventional treatment group) who completed baPWV measurement at baseline. RESULTS: In a mixed-effects model, the progression in the right, left, and mean baPWV over 104 weeks was significantly attenuated with tofogliflozin compared to that with conventional treatment (- 109.3 [- 184.3, - 34.3] (mean change [95% CI] cm/s, p = 0.005; - 98.3 [- 172.6, - 24.1] cm/s, p = 0.010; - 104.7 [- 177.0, - 32.4] cm/s, p = 0.005, respectively). Similar findings were obtained even after adjusting the mixed-effects models for traditional cardiovascular risk factors, including body mass index (BMI), glycated hemoglobin (HbA1c), total cholesterol, high-density lipoprotein (HDL)-cholesterol, triglyceride, systolic blood pressure (SBP), hypertension, smoking, and/or administration of drugs, including hypoglycemic agents, antihypertensive agents, statins, and anti-platelets, at baseline. The findings of the analysis of covariance (ANCOVA) models, which included the treatment group, baseline baPWV, and traditional cardiovascular risk factors, resembled those generated by the mixed-effects models. CONCLUSIONS: Tofogliflozin significantly inhibited the increased baPWV in patients with T2DM without a history of apparent cardiovascular disease, suggesting that tofogliflozin suppressed the progression of arterial stiffness. Trial Registration UMIN000017607. Registered 18 May 2015. ( https://www.umin.ac.jp/icdr/index.html ).

Tofogliflozin does not delay progression of carotid atherosclerosis in patients with type 2 diabetes: a prospective, randomized, open-label, parallel-group comparative study.

BACKGROUND: This study aimed to investigate the preventive effects of tofogliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, on atherosclerosis progression in type 2 diabetes (T2DM) patients without apparent cardiovascular disease (CVD) by monitoring carotid intima-media thickness (IMT). METHODS: This prospective, randomized, open-label, blinded-endpoint, multicenter, parallel-group, comparative study included 340 subjects with T2DM and no history of apparent CVD recruited at 24 clinical units. Subjects were randomly allocated to either the tofogliflozin treatment group (n = 169) or conventional treatment group using drugs other than SGLT2 inhibitors (n = 171). Primary outcomes were changes in mean and maximum common carotid IMT measured by echography during a 104-week treatment period. RESULTS: In a mixed-effects model for repeated measures, the mean IMT of the common carotid artery (mean-IMT-CCA), along with the right and left maximum IMT of the CCA (max-IMT-CCA), significantly declined in both the tofogliflozin (- 0.132 mm, SE 0.007; - 0.163 mm, SE 0.013; - 0.170 mm, SE 0.020, respectively) and the control group (- 0.140 mm, SE 0.006; - 0.190 mm, SE 0.012; - 0.190 mm, SE 0.020, respectively). Furthermore, the tofogliflozin and the conventional treatment group did not significantly differ in the progression of the mean-IMT-CCA (mean change (95% CI) 0.008 (- 0.009, 0.025) mm, P = 0.34), along with the right (mean change (95% CI) 0.027 (- 0.005, 0.059) mm, P = 0.10) and the left max-IMT-CCA (mean change (95% CI) 0.020 (- 0.030, 0.070), P = 0.43). Similar findings were obtained even after adjusting for traditional CV risk factors and/or administration of drugs at baseline. Relative to the control treatment effects, tofogliflozin significantly reduced the HbA1c, blood glucose level, body weight/body mass index, abdominal circumference, and systolic blood pressure, and significantly increased the HDL-C. The total and serious adverse events incidences did not significantly vary between the treatment groups. CONCLUSIONS/INTERPRETATION: No IMT changes were observed between the tofogliflozin and the conventional treatment groups. However, tofogliflozin is a safe and effective treatment option for managing primary CVD risk factors in this population. Clinical Trial Registration UMIN000017607 ( https://www.umin.ac.jp/icdr/index.html ).

Neuropsychiatric Immune-related Adverse Events Induced by Pembrolizumab in a Patient with Lung Adenocarcinoma and Systemic Lupus Erythematosus.

The patient was a 73-year-old woman with lung adenocarcinoma and systemic lupus erythematosus (SLE) who was treated with pembrolizumab. After six cycles of pembrolizumab, she developed symptoms suggestive of neuropsychiatric SLE, such as resting tremor, confusional state, depression, mood disorder, and anxiety disorder. In addition, her cerebrospinal fluid level of interleukin-6 was elevated. Her symptoms resolved one month after the discontinuation of pembrolizumab. This is the first report of neuropsychiatric symptoms in a patient with lung cancer and SLE on immune checkpoint blockade therapy.

Two cases with Hb Andrew-Minneapolis showing high or low-normal HbA1c levels depending on the measurement method.

We experienced two cases of Hb Andrew-Minneapolis with high or low-normal HbA1c levels depending on the measurement method. Case 1 was a 25-year-old male, and case 2 was a 32-year-old pregnant woman. Both cases showed normal glucose tolerance levels and glycated albumin within the reference range. In both cases, the high-performance liquid chromatography (HPLC) method (standard mode) showed high HbA1c levels of 6.8% and 6.5%, respectively, while the HbA1c levels measured by immunoassay were low normal at 4.6% in both cases. Globin gene analysis detected heterozygous ß-chain mutations (ß144Lys → Asn) in both cases, which resulted in the diagnosis of Hb Andrew-Minneapolis. In case 1, a high-resolution HPLC chromatogram showed multiple abnormal peaks; two unknown peaks in addition to variant hemoglobin (HbX0) and glycation products of variant hemoglobin (HbX1c) were observed after in vitro glycation reaction. Although the details of unknown peaks were not identified, those might be modified hemoglobin associated with variant hemoglobin. The presence of unknown peaks could cause high HbA1c levels measured by HPLC (standard mode). Furthermore, the HbA1c level measured by immunoassay was increased to 4.9% within the reference range after adjustment for modified hemoglobin in case 1. Consequently, the high HbA1c levels measured by HPLC (standard mode) and the low-normal HbA1c level measured by immunoassay might be due to modified hemoglobin associated with variant hemoglobin.

A case of monoclonal gammopathy of undetermined significance with abnormal low levels of plasma glycated albumin by M protein.

BACKGROUND: It is known that an immunoglobulin abnormality affects various clinical laboratory measurements and leads to abnormal values. We experienced a case of monoclonal gammopathy of undetermined significance (MGUS) showing a falsely low plasma glycated albumin (GA) level. CASE REPORT: The patient was a 75-y-old male who visited our hospital for thrombocytosis identified during a medical checkup. Based on further examinations, he was diagnosed with MGUS (IgM-κ type). Laboratory examinations revealed that the plasma GA level was significantly low at -1.3% but the serum GA level was reasonable at 15.5%. We investigated the cause of the falsely low plasma GA level. RESULTS: The patient's plasma became turbid after mixing with the first reagent for GA measurement. The plasma GA level was increased by dilution of the plasma. The plasma GA level was falsely decreased only at the time of measurement on a sample collected using a blood-collecting tube with heparin sodium. The GA level was decreased by adding heparin sodium to the patient's serum, whereas the GA level was increased by neutralization of the patient's plasma with protamine sulfate. The GA level was increased after adding polyethylene glycol to the patient's plasma. Serum GA levels in healthy controls were decreased by adding purified M protein from the patient's serum. CONCLUSIONS: We report a patient with MGUS whose plasma GA concentration was falsely decreased by M protein when blood was drawn in a heparin sodium-containing tube.

Rationale, Design, and Baseline Characteristics of the Utopia Trial for Preventing Diabetic Atherosclerosis Using an SGLT2 Inhibitor: A Prospective, Randomized, Open-Label, Parallel-Group Comparative Study.

INTRODUCTION: Sodium-glucose co-transporter-2 (SGLT2) inhibitors are anti-diabetic agents that improve glycemic control with a low risk of hypoglycemia and ameliorate a variety of cardiovascular risk factors. The aim of the ongoing study described herein is to investigate the preventive effects of tofogliflozin, a potent and selective SGLT2 inhibitor, on the progression of atherosclerosis in subjects with type 2 diabetes (T2DM) using carotid intima-media thickness (IMT), an established marker of cardiovascular disease (CVD), as a marker. METHODS: The Study of Using Tofogliflozin for Possible better Intervention against Atherosclerosis for type 2 diabetes patients (UTOPIA) trial is a prospective, randomized, open-label, blinded-endpoint, multicenter, and parallel-group comparative study. The aim was to recruit a total of 340 subjects with T2DM but no history of apparent CVD at 24 clinical sites and randomly allocate these to a tofogliflozin treatment group or a conventional treatment group using drugs other than SGLT2 inhibitors. As primary outcomes, changes in mean and maximum IMT of the common carotid artery during a 104-week treatment period will be measured by carotid echography. Secondary outcomes include changes in glycemic control, parameters related to ß-cell function and diabetic nephropathy, the occurrence of CVD and adverse events, and biochemical measurements reflecting vascular function. CONCLUSION: This is the first study to address the effects of SGLT2 inhibitors on the progression of carotid IMT in subjects with T2DM without a history of CVD. The results will be available in the very near future, and these findings are expected to provide clinical data that will be helpful in the prevention of diabetic atherosclerosis and subsequent CVD. FUNDING: Kowa Co., Ltd. CLINICAL TRIAL REGISTRATION: UMIN000017607.

Metformin decreases glycated albumin to glycated haemoglobin ratio in patients with newly diagnosed type 2 diabetes.

BACKGROUND: To know whether metformin improves postprandial hyperglycaemia, we examined the effect of metformin on the glycated albumin (GA) to glycated haemoglobin (HbA1c) ratio (GA/HbA1c ratio) in patients with newly diagnosed type 2 diabetes. METHODS: Metformin and lifestyle interventions were initiated in 18 patients with newly diagnosed type 2 diabetes. Metformin was titrated to 1500 mg/day or maximum-tolerated dose. HbA1c and GA were measured every four weeks up to 24 weeks. RESULTS: HbA1c decreased significantly from 9.0 ± 2.1% at baseline to 6.5 ± 0.9% at week 24, and GA decreased significantly from 24.3 ± 8.2% to 16.2 ± 3.1%. The GA/HbA1c ratio decreased significantly from 2.66 ± 0.37 at baseline to 2.47 ± 0.29 at week 24 (P<0.01), despite that the GA/HbA1c ratio reached a plateau value at week 16. The change in the GA/HbA1c ratio during 24 weeks (ΔGA/HbA1c ratio) was significantly correlated with both baseline HbA1c and GA. Moreover, the ΔGA/HbA1c ratio was significantly correlated with the change in GA during 24 weeks but not with the change in HbA1c. CONCLUSIONS: Metformin decreased the GA/HbA1c ratio in patients with newly diagnosed type 2 diabetes. This suggests that metformin improves postprandial hyperglycaemia in patients with newly diagnosed type 2 diabetes.

Effectiveness of metformin and lifestyle interventions as an initial treatment in Japanese patients with newly diagnosed type 2 diabetes: a prospective observational study.

Although global guidelines recommend metformin and lifestyle interventions as an initial treatment in patients with newly diagnosed type 2 diabetes (T2DM), few reports exist about its effectiveness in Japanese patients. To examine its effectiveness, we performed a prospective observational study within a routine clinical setting. We provided metformin (≥1,500 mg/day) and lifestyle interventions to 23 patients with newly diagnosed T2DM (20 men and 3 women, mean age 53 years, mean body mass index [BMI] 25.7 kg/m(2)). After 16 weeks, HbA1c levels significantly decreased from 9.1±2.1% (mean±SD) to 6.6±0.8% (p<0.001). Thirteen patients (56.5%) achieved a target HbA1c<6.5%. We did not find a significant correlation between baseline BMI and the changes in HbA1c (ΔHbA1c) (r=-0.165, p=0.451). In contrast, we found a significant correlation between baseline fasting plasma glucose and ΔHbA1c (r=-0.755, p<0.001). Body weight decreased from 73.3±13.3 kg to 69.8±11.6 kg (p<0.001). Total cholesterol, low density lipoprotein - cholesterol, non-high density lipoprotein-cholesterol, and serum vitamin B-12 concentrations also significantly decreased. Adverse events included diarrhea (26.1%) and mild elevation of liver enzymes (8.7%). These results suggest that metformin and lifestyle interventions is effective and safe as an initial treatment in Japanese patients with newly diagnosed T2DM.

Effects of pitavastatin on serum lipids and high sensitivity C-reactive protein in type 2 diabetic patients.

AIM: Previous studies have been inconsistent results about the effects of statins on serum triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and high sensitivity C-reactive protein (hsCRP) levels. We therefore investigated the effects of pitavastatin on serum lipid profiles and hsCRP levels in patients with type 2 diabetes mellitus. METHODS: The study population was 65 Japanese type 2 diabetic patients who had been administered 2 mg daily of pitavastatin and completed a 6-month follow-up. Serum lipids and hsCRP were measured before and after treatment for 1, 3, and 6 months. RESULTS: Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and TG had significantly reduced after 1 month and remained reduced for 6 months, while HDL-C levels had significantly increased after 1 month and remained at the higher level for 6 months. Baseline median levels of hsCRP were 0.49 mg/L and showed a significant reduction to 0.37 mg/L at 6 months' treatment (p<0.001). Six-month changes in hsCRP levels were not associated with those in TC, LDL-C, HDL-C or TG. CONCLUSION: Pitavastatin improved serum lipid profiles and reduced serum hsCRP levels in type 2 diabetic patients with relatively low inflammation. The effect on hsCRP was not related to the effects on serum lipid profiles.

The thiazolidinedione drug troglitazone up-regulates nitric oxide synthase expression in vascular endothelial cells.

Endothelial dysfunction is a phenomenon often observed in diabetic patients, which is a cause for vascular complications of diabetes mellitus. Endothelium-derived nitric oxide (NO) is responsible for vasodilatation, and NO-dependent vasodilatation is diminished in diabetic patients. In the present study, we evaluated the effects of thiazolidinediones (TZDs), antidiabetic drugs known to improve insulin resistance and to have vasodilating properties, on endothelial NO synthase (eNOS) expression in cultured vascular endothelial cells. Human umbilical vein endothelial cells were treated with the TZDs troglitazone and pioglitazone, or the peroxisome proliferator-activated receptor (PPAR) gamma activator 15-deoxy-Delta(12,14)-prostaglandin J(2) (15-dPGJ2). The expression of eNOS protein and its mRNA was determined by Western and Northern blot analyses, respectively. The effect of alpha-tocopherol that possesses structural similarity to troglitazone was also examined. Troglitazone up-regulated eNOS protein and its mRNA levels, whereas pioglitazone and 15-dPGJ2 failed to increase their levels. By contrast, alpha-tocopherol also increased in eNOS protein and mRNA. These results suggest that troglitazone up-regulates eNOS expression probably through its 6-hydroxychromanes structure but not activating PPARgamma.

Suppressor of cytokine signaling 1 suppresses muscle differentiation through modulation of IGF-I receptor signal transduction.

Suppressor of cytokine signaling (SOCS) 1 was initially identified as an intracellular negative feedback regulator of the JAK-STAT signal pathway. Recently, it has been suggested that SOCS1 affects signals of growth factors and hormones. One of them, SOCS1, is also known to be involved in auto-regulation of IRS-1-mediated signaling. However, the mechanism(s) of SOCS1 induction by insulin-like growth factor (IGF)-I and a role of SOCS1 on IGF-I receptor-mediated signaling are not clarified. Here, we investigate SOCS1 on muscle differentiation. We found that muscle differentiation was suppressed in SOCS1 stable transformant C2C12 myoblasts, while it was promoted in SOCS1-deficient myoblasts. Additionally, SOCS1 augmented MEK phosphorylation and reduced Akt phosphorylation induced by IGF-I. Then, SOCS1 stable transformant C2C12 myoblasts, infected with adenovirus bearing constitutively active Akt, have the ability to differentiate again. Collectively, these findings suggest that SOCS1 suppresses muscle differentiation through negative feedback regulation of IGF-I receptor-mediated signaling.

Peroxisome proliferator-activated receptor alpha agonists increase nitric oxide synthase expression in vascular endothelial cells.

OBJECTIVE: There has been accumulating evidence demonstrating that activators for peroxisome proliferator-activated receptor alpha (PPARalpha) have antiinflammatory, antiatherogenic, and vasodilatory effects. We hypothesized that PPARalpha activators can modulate endothelial nitric oxide synthase (eNOS) expression and its activity in cultured vascular endothelial cells. METHODS AND RESULTS: Bovine aortic endothelial cells were treated with the PPARalpha activator fenofibrate. The amount of eNOS activity and the expression of eNOS protein and its mRNA were determined. Our data show that treatment with fenofibrate for 48 hours resulted in an increase in eNOS activity. Fenofibrate failed to increase eNOS activity within 1 hour. Fenofibrate also increased eNOS protein as well as its mRNA levels. RU486, which has been shown to antagonize PPARalpha action, inhibited the fenofibrate-induced upregulation of eNOS protein expression. WY14643 and bezafibrate also increased eNOS protein levels, whereas rosiglitazone did not. Transient transfection experiments using human eNOS promoter construct showed that fenofibrate failed to enhance eNOS promoter activity. Actinomycin D studies demonstrated that the half-life of eNOS mRNA increased with fenofibrate treatment. CONCLUSIONS: PPARalpha activators upregulate eNOS expression, mainly through mechanisms of stabilizing eNOS mRNA. This is a new observation to explain one of the mechanisms of PPARalpha-mediated cardiovascular protection.

Runx2 deficiency in chondrocytes causes adipogenic changes in vitro.

Runx2 (runt-related transcription factor 2) is an important transcription factor for chondrocyte differentiation as well as for osteoblast differentiation. To investigate the function of Runx2 in chondrocytes, we isolated chondrocytes from the rib cartilage of Runx2-deficient (Runx2-/-) mice and examined the effect of Runx2 deficiency on chondrocyte function and behavior in culture for up to 12 days. At the beginning of the culture, Runx2-/- chondrocytes actively proliferated, had a polygonal shape and expressed type II collagen; these are all characteristics of chondrocytes. However, they gradually accumulated lipid droplets that stained with oil red O and resembled adipocytes. Northern blot analysis revealed that the expression of adipocyte-related differentiation marker genes including PPAR gamma (peroxisome proliferator-activated receptor gamma), aP2 and Glut4 increased over time in culture, whereas expression of type II collagen decreased. Furthermore, the expression of Pref-1, an important inhibitory gene of adipogenesis, was remarkably decreased. Adenoviral introduction of Runx2 or treatment with transforming growth factor-beta, retinoic acid, interleukin-1 beta, basic fibroblast growth factor, platelet-derived growth factor or parathyroid hormone inhibited the adipogenic changes in Runx2-/- chondrocytes. Runx2 and transforming growth factor-beta synergistically upregulated interleukin-11 expression, and the addition of interleukin-11 to the culture medium reduced adipogenesis in Runx2-/- chondrocytes. These findings indicate that depletion of Runx2 resulted in the loss of the differentiated phenotype in chondrocytes and induced adipogenic differentiation in vitro, and show that Runx2 plays important roles in maintaining the chondrocyte phenotype and in inhibiting adipogenesis. Our findings suggest that these Runx2-dependent functions are mediated, at least in part, by interleukin-11.

New analytical method for pancreas and liver regeneration: normalization of streptozotocin-induced hyperglycemia by retrograde injection of insulin producing cells.

We established a new analytical system in which functioning cells were transplanted directly into the pancreas and liver. The retrograde transplantation of beta cell line, Min6 cells, into the streptozotocin-diabetic mice normalized plasma glucose and insulin levels. The injected cells were protected from pancreatic enzymes with enzyme inhibitor. Blood glucose decreased gradually over 10 days and the diabetic mice recovered weight at the same time. Intraperitoneal glucose tolerance test showed that the peak of plasma glucose of the transplanted mice was less than half that of the control. The insulin secretion of the transplanted mice was recovered and stimulated 4.6 times from the basal secretion. Histological analyses showed that the pancreas and liver were characterized by Min6 cell clusters dispersed throughout the organs. Min6 cells were detected near the pancreatic or bile ducts. It is suggested that the injected cells obstructed the peripheral ducts where they settled. The weight of pancreas and liver did not differ significantly in either Min6 transplanted or the control mice. The metabolic effects on the weights of these organs appeared the same in both groups. This is the first report that cells transplanted via ducts into the pancreas and liver performed their biological function. Our transplantation model makes possible the in vivo analysis of the regeneration machinery of the pancreas and liver.

RU486 antagonizes the inhibitory effect of peroxisome proliferator-activated receptor alpha on interleukin-6 production in vascular endothelial cells.

Peroxisome proliferator-acitivated receptor alpha (PPARalpha) is a member of nuclear receptor superfamily. Recent studies have shown that the activators for PPARalpha inhibit the expression of some inflammatory molecules in vascular endothelial cells (ECs) and vascular smooth muscle cells, indicating the anti-inflammatory roles of PPARalpha on vascular walls. In this investigation, we showed that RU486, already proved to be an active anti-glucocorticoid and anti-progesterone agent, blocked the inhibition of tumor necrosis factor (TNF)-alpha-stimulated interleukin-6 (IL-6) production by the PPARalpha activator fenofibrate in human umbilical vein ECs. Transient transfection of bovine aortic ECs with an IL-6 promoter construct demonstrated that RU486 blocked the inhibitory effect of fenofibrate on TNF-alpha-induced IL-6 promoter activity. By fluorescence microscopy, RU486 was found to prevent fenofibrate-induced nuclear translocation of PPARalpha. Thus, RU486 has an antagonizing effect on PPARalpha-mediated down-regulation of IL-6 in vascular ECs. This effect may be exerted by its interference with the nuclear translocation of PPARalpha.

Akt1 and Akt2 differently regulate muscle creatine kinase and myogenin gene transcription in insulin-induced differentiation of C2C12 myoblasts.

Insulin and IGFs are potent inducers of skeletal muscle differentiation. Although PI3K is known to be involved in skeletal muscle differentiation, its downstream targets in this process are not clearly defined. We investigated the roles of Akt and mammalian target of rapamycin (mTOR) in skeletal muscle differentiation. LY294002, a pharmacological inhibitor of PI3K, and the immunosuppressant rapamycin inhibited insulin-induced differentiation of C2C12 myoblasts. LY294002 and rapamycin suppressed myosin heavy chain expression and myotube formation. Transient reporter assays showed that both inhibitors repress muscle creatine kinase (MCK) and myogenin gene transcription. Heterologous expression of Akt1/PKB(alpha) potently suppressed MCK gene transcription without affecting myogenin gene transcription, whereas heterologous expression of Akt2 increased myogenin and MCK gene transcription. Finally, overexpression of myogenin rescued the inhibitory effect of rapamycin on MCK gene transcription, whereas it failed to rescue the inhibitory effect of LY294002 and Akt1. These results suggest that insulin regulates myogenic differentiation chiefly at the level of myogenin gene transcription via PI3K and mTOR. PI3K activity, but not mTOR, may regulate transcriptional activity of myogenin. Our data also suggest that Akt1 and Akt2 play distinct roles in myogenic differentiation.