Our library of drug research abstracts drawn from the medical literature is updated on a regular schedule, and you can be assured that new rosiglitazone research articles will be listed here shortly after becoming available to us.
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Medical research on rosiglitazone
J Dairy Sci. 2008 Jul; 91(7): 2808-13
Bionaz M, Baumrucker CR, Shirk E, Vanden Heuvel JP, Block E, Varga GA
The peroxisome proliferator-activated receptors (PPAR) are critical for lipid metabolism, and many fatty acids are PPAR agonists. Madin-Darby bovine kidney (MDBK) cells were tested as an in vitro bovine model for PPAR activation, and preliminary evaluation of the effect of fatty acids on bovine PPAR was performed. Cells were treated with Wy-14643 (WY, specific PPARalpha agonist) and rosiglitazone (ROSI, specific PPARgamma agonist). The gene expression of specific PPARalpha-responsive genes such as carnitine palmitoyl transferase-1 (CPT1A) and acetyl coenzyme A oxidase (ACOX1) and of PPARgamma-responsive gene lipoprotein lipase (LPL) were analyzed using real-time reverse transcription PCR. It was found that CPT1A exhibited a significant increase in cells treated with WY, whereas the ACOX1 gene expression was not altered. The LPL gene expression showed an increase in response to ROSI. Interestingly, LPL was almost undetectable in MDBK cells not treated with ROSI. The potency of different fatty acids in activating PPARalpha as assessed by CPT1A mRNA abundance in MDBK cells was also tested. The mRNA of CPT1A (2.5- to 1.4-fold) was significantly increased by fatty acids in the order of palmitate > linolenate > linoleate > conjugated linoleate, and oleate. The results demonstrated MDBK cells to be responsive to PPAR agonists and thus a promising model to evaluate the role of PPAR in bovine cells. In addition, fatty acids were proven to have a different potency in modulating expression of CPT1A through PPARalpha.
Rosiglitazone reverses tenofovir-induced nephrotoxicity.
Kidney Int. 2008 Jun 18;
Libório AB, Andrade L, Pereira LV, Sanches TR, Shimizu MH, Seguro AC
Tenofovir disoproxil fumarate (TDF) is a first-line drug used in patients with highly active retroviral disease; however, it can cause renal failure associated with many tubular anomalies that may be due to down regulation of a variety of ion transporters. Because rosiglitazone, a peroxisome proliferator-activated receptor-gamma agonist induces the expression of many of these same transporters, we tested if the nephrotoxicity can be ameliorated by its use. High doses of TDF caused severe renal failure in rats accompanied by a reduction in endothelial nitric-oxide synthase and intense renal vasoconstriction; all of which were significantly improved by rosiglitazone treatment. Low-dose TDF did not alter glomerular filtration rate but produced significant phosphaturia, proximal tubular acidosis, polyuria and a reduced urinary concentrating ability. These alterations were caused by specific downregulation of the sodium-phosphorus cotransporter, sodium/hydrogen exchanger 3 and aquaporin 2. A Fanconi's-like syndrome was ruled out as there was no proteinuria or glycosuria. Rosiglitazone reversed TDF-induced tubular nephrotoxicity, normalized urinary biochemical parameters and membrane transporter protein expression. These studies suggest that rosiglitazone treatment might be useful in patients presenting with TFV-induced nephrotoxicity especially in those with hypophosphatemia or reduced glomerular filtration rate.Kidney International advance online publication, 18 June 2008; doi:10.1038/ki.2008.252.
ROSIGLITAZONE IS CARDIOPROTECTIVE IN A MURINE MODEL OF MYOCARDIAL I/R.
Shock. 2008 Jul; 30(1): 64-68
Mersmann J, Tran N, Zacharowski PA, Grotemeyer D, Zacharowski K
The peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a regulator of anti-inflammatory genes. One of its agonists, rosiglitazone-widely used in the treatment of type 2 diabetes mellitus-has recently been reported to increase the risk for myocardial infarction. In contrast, various studies provide evidence for a rosiglitazone-induced cardioprotection in different models of acute myocardial I/R. Here, we report that this protection can still be observed after 28 days of reperfusion in a murine model even when treatment commenced after the period of ischemia (reperfusion therapy). In vitro, cells from the rat cardiomyoblast cell line H9c2(2-1) are protected against oxidative stress by incubation with rosiglitazone, which can be abrogated by dexamethasone or cycloheximide. The antioxidant enzyme heme oxygenase 1 is up-regulated in these cells after rosiglitazone treatment. Our data provide further evidence that rosiglitazone exerts protective effects during myocardial I/R and might contribute to the reevaluation of the approved drug rosiglitazone.
Dysregulation of adipose GPx3 in obesity contributes to local and systemic oxidative stress.
Mol Endocrinol. 2008 Jun 18;
Lee YS, Kim AY, Choi JW, Kim M, Yasue S, Son HJ, Masuzaki H, Park KS, Kim JB
Glutathione peroxidase 3 (GPx3) accounts for the major anti-oxidant activity in the plasma. Here, we demonstrate that downregulation of GPx3 in the plasma of obese subjects is associated with adipose GPx3 dysregulation, resulted from the increase of inflammatory signals and oxidative stress. Although GPx3 was abundantly expressed in kidney, lung, and adipose tissue, we observed that GPx3 expression was reduced selectively in the adipose tissue of several obese animal models as decreasing plasma GPx3 level. Adipose GPx3 expression was greatly suppressed by pro-oxidative conditions such as high levels of TNFalpha and hypoxia. In contrast, the anti-oxidant N-acetyl cystein (NAC) and the anti-diabetic drug rosiglitazone increased adipose GPx3 expression in obese and diabetic db/db mice. Moreover, GPx3 overexpression in adipocytes improved high glucose-induced insulin resistance and attenuated inflammatory gene expression whereas GPx3 neutralization in adipocytes promoted expression of proinflammatory genes. Taken together, these data suggest that suppression of GPx3 expression in the adipose tissue of obese subjects might constitute a vicious cycle to expand local ROS accumulation in adipose tissue potentially into systemic oxidative stress and obesity-related metabolic complications.
The effects of rosiglitazone on aortic atherosclerosis of cholesterol-fed rabbits.
Thromb Res. 2008 Jun 16;
Zhao S, Zhang C, Lin Y, Yang P, Yu Q, Chu Y, Yang P, Fan J, Liu E
INTRODUCTION: Thiazolidinedione (TZD) is widely used a drug for the treatment of type 2 diabetes and protects against cardiovascular events in human. However, it is not clear whether TZD can directly inhibit the progression of atherosclerosis. To test the hypothesis whether administration of TZD could reduce the development of atherosclerosis, we studied the effects of rosiglitazone on aortic atherosclerosis of rabbits fed a cholesterol diet. MATERIALS AND METHODS: Male Japanese White rabbits were fed a diet containing either 0.3% cholesterol diet (control group, n=10) or 0.3% cholesterol with rosiglitazone (TZD-treated group, n=12) for 16 weeks. We compared the plasma lipids and the extent of aortic atherosclerosis between two groups. RESULTS AND CONCLUSIONS: TZD treatment significantly resulted in the reduction of aortic atherosclerosis by 21% in the aortic arch (p
Cell Mol Life Sci. 2008 Jun 14;
Abaraviciene SM, Lundquist I, Salehi A
Chronic exposure of pancreatic islets to elevated levels of palmitate leads to beta-cell dysfunction. We examined possible involvement of mitogenactivated protein kinases (MAPKs) and caspase-3 in palmitate-induced beta-cell dysfunction and tested the influence of the anti-diabetic drug rosiglitazone (ROZ). Palmitate amplified glucose-stimulated augmentation of intracellular free calcium ([Ca(2+)](i)) and insulin secretion in incubated islets. ROZ suppressed this amplification, whereas it modestly augmented glucose-induced increase in these events. ROZ suppressed short-term palmitate-induced phosphorylation of pro-apoptotic MAPKs, i.e., SAPK/JNK and p38. Long-term islet culturing with palmitate induced inducible nitric oxide synthase (iNOS) and activated SAPK/JNK-p38. ROZ counteracted these effects. Both palmitate and cytokines activated caspase-3 in MIN6c4-cells and isolated islets. ROZ suppressed palmitate- but not cytokine-induced caspase-3 activation. Finally, after palmitate culturing, ROZ reversed the inhibitory effect on glucose-stimulated insulin release. We suggest that ROZ counteracts palmitateinduced deleterious effects on beta-cell function via suppression of iNOS, pro-apoptotic MAPKs and caspase-3 activities, as evidenced by restoration of glucose-stimulated insulin release.
A Phase I Study of Bexarotene and Rosiglitazone in Patients with Refractory Cancers.
Chemotherapy. 2008 Jun 18; 54(3): 236-241
Read WL, Baggstrom MQ, Fracasso PM, Govindan R
Background: Preclinical studies have shown that binding of PPAR-gamma (polysome-proliferator activated receptor gamma) and retinoid-X receptor (RXR) to their ligands can slow growth and promote differentiation of malignant cells. Rosiglitazone, a PPAR-gamma ligand, is approved for treatment of insulin-resistant diabetes, and bexarotene, a RXR ligand, is approved for treatment of cutaneous T-cell lymphoma. After binding to its ligand, the PPAR-gamma receptor heterodimerizes with the RXR resulting in synergistic effects in preclinical models. We conducted a phase I study of bexarotene and rosiglitazone to define the MTD of rosiglitazone in this combination regimen. Methods: Patients with resistant solid tumors received bexarotene 300 mg/m(2)/day. The starting dose of rosiglitazone was 4 mg/day and was escalated in five cohorts by 2-mg increments up to 12 mg/day. Both drugs were continued until disease progression or toxicity was observed. Patients received atorvastatin 10 mg/day to control bexarotene-related hypertriglyceridemia. Results: Twenty-three patients were enrolled, with a median of 4 prior regimens (range 0-8). The study was closed after completing the 12 mg/day cohort without encountering dose-limiting toxicity. The most common grade 3 or 4 toxicities were hypertriglyceridemia (17%), dyspnea (9%), nausea (9%), and dehydration (9%). No objective responses were observed. Conclusions: The combination of bexarotene (300 mg/m(2)/day) and rosiglitazone (12 mg/day) is safe and feasible but did not result in objective responses in heavily pretreated patients with solid tumors. This combination is suitable for evaluation in other conditions such as hematologic malignancies and inflammatory diseases.
Ligand-Induced Stabilization and Activation of Peroxisome Proliferator-Activated Receptor gamma.
Chem Biol Drug Des. 2008 Jun 11;
Gani OA, Sylte I
Peroxisome proliferator-activated receptor gamma belongs to the nuclear receptor superfamily and is activated by the antidiabetic drugs rosiglitazone and pioglitazone. Ligand-independent constitutive activity of peroxisome proliferator-activated receptor gamma is also demonstrated. X-ray crystallographic structures show that the active or inactive conformations of the receptor are determined by the position of helix 12 in the C-terminal end. In this study, molecular dynamics simulations were used to gain molecular insight into the activation process and the structural stability of inactive and active peroxisome proliferator-activated receptor gamma receptor structure. The simulations showed: (i) during molecular dynamics simulations without agonist at the active site, the receptor structure with helix 12 in a position corresponding to activated receptor structure was structurally more stable than with helix 12 in a position corresponding to inactive receptor structure, which may contribute to the constitutive activity of the receptor; (ii) docosahexenoic acid stabilized the active receptor conformation more efficiently than the glitazones; (iii) docosahexenoic acid, but not glitazones, induced structural changes into the inactive receptor structure such that helix 12 was shifted into a position more similar to that of an active receptor structure, which indicate that docosahexenoic acid is a more effective peroxisome proliferator-activated receptor gamma agonist than the glitazones.
Effects of Momordica charantia on insulin resistance and visceral obesity in mice on high-fat diet.
Diabetes Res Clin Pract. 2008 Jun 10;
Shih CC, Lin CH, Lin WL
We examined the preventive effect of Momordica charantia L. fruit (bitter melon) on hyperglycemia and insulin resistance in C57BL/6J mice fed with a high-fat (HF) diet. Firstly, mice were divided randomly into two groups: the control group was fed low-fat (LF) diet, whereas the experimental group was fed with a 45% HF diet last for 12 weeks. After 8 week of induction, the HF group was subdivided into six groups and was given orally with or without M. charantia or rosiglitazone 4 weeks afterward. We demonstrated that bitter melon was effective in ameliorating the HF diet-induced hyperglycemia, hyperleptinemia, and decreased the levels of blood glycated hemoglobin (HbA1c) and free fatty acid (FFA) (P
A combination of CLA-DAG oil modifies the diabetic phenotype in male Zucker diabetic fatty rats.
Horm Metab Res. 2008 Apr; 40(4): 262-8
Iqbal MJ, Higginbotham A, Chickris N, Bollaert M, Rockway S, Banz WJ
A number of human and animal studies using conjugated linoleic acids (CLA) or diacylglycerol (DAG) oil have shown positive physiological effects on abdominal adiposity, plasma triglycerides, plasma glucose, and insulin sensitivity. A novel DAG composition containing CLA called CLA diacylglyceride (CLA-DAG) may offer potential as a therapeutic agent in reducing some of the symptoms associated with the diabetic phenotype and metabolic syndrome. This study was designed to investigate the effect of CLA-DAG oil on the diabetic phenotype in male Zucker diabetic fatty rats. Animals were assigned to one of four groups: control (C), rosiglitazone (ROS), CLA-DAG, or CLA as free fatty acid (CLA-FFA). After 11 weeks, body weight was higher and kidney weight was lower in the CLA-DAG and ROS groups compared with the C group. The ROS treatment increased the percentage of body fat as compared with all other groups. Final fasting blood glucose was lower in the CLA-DAG and ROS groups than in the C group. Plasma cholesterol was lower in the CLA-DAG group, and plasma triglycerides were lower in the ROS group compared with the C group. We also observed changes in transcript abundance of PPAR-gamma, PPAR-alpha, FAS, LPL, UCP2, UCP3, CPT1, RxR, ObRb, ApoAII, ApoD, and IRS1 in liver, muscle, and adipose tissue, suggesting treatment-induced effects on these genes. Collectively, these data suggest the need for further research on the therapeutic relevance of CLA-DAG oil in obesity and diabetes. Future research should also differentiate between CLA alone and DAG alone compared with the combination.