Acetaminophen has a reasonable safety profile when consumed in therapeutic doses. However, it could induce hepatotoxicity and even acute liver failure when taken at an overdose. Pioglitazone, PPARγ ligand, is clinically tested and used in treatment of diabetes. PPARγ is a key nuclear hormone receptor of lipid metabolisms and regulates several gene transcriptions associated with differentiation, growth arrest, and apoptosis. The aim of our study was to evaluate the hepatoprotective activity of pioglitazone on acetaminophen-induced hepatotoxicity and to understand the relationship between the PPARγ and acetaminophen-induced hepato injury. For the experiment, Sprague-Dawley rats (160-180 g) were used and divided into four groups. Groups I and II were normal and experimental controls, respectively. Groups III and IV received the pioglitazone 20 mg/kg for 10 days. Hepatotoxicity was induced in Groups II and III on the eighth day with acetaminophen (i.p. 350 mg/kg body weight). The hepatoprotective effect was evaluated by performing an assay of the total protein, total bilirubin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and α-fetoprotein as well as glutathione peroxidase, lipid peroxidation, catalase, superoxide dismutase, and glutathione transferase and liver histopathology. The assay results were presented as mean and standard error of mean for each group. The study group was compared with the control group by one-way ANOVA test. A p value of <0.05 was considered significant. Pioglitazone significantly reduced the elevated level of above serum marker enzymes and also inhibits the free radical formation by scavenging hydroxyl ions. It also restored the level of LPO and significantly elevated the levels of endogenous antioxidant enzymes in acetaminophen-challenged hepatotoxicity. Liver histopathological examination showed that pioglitazone administration antagonized acetaminophen -induced liver pathological damage. Various biochemical estimations of different hepatic markers and antioxidant enzymes and histopathological studies of liver tissues glimpse a support to its significant hepatoprotective activity on acetaminophen -induced hepatotoxicity.
Rosiglitazone is an oral hypoglycaemic agent of the thiazolidinedione group. This study aimed to assess changes in the diabetic prothrombotic state via plasminogen activity and changes in surrogate markers of atherosclerotic burden via ankle-brachial pressure index (ABPI) measurements after rosiglitazone was added to a pre-existing type 2 diabetes mellitus treatment regime. A nonblinded interventional study was designed. Fifty-nine patients were enrolled. Rosiglitazone-naïve patients were prescribed oral rosiglitazone 4 mg daily for 10 weeks. ABPI, plasminogen activity, glycosylated haemoglobin (HbA1c) and fasting lipid profile were measured pretreatment and post-treatment. Forty-eight patients completed the study. At the end of this study, mean plasminogen activity improvement was nearly 16% (P<0.05), mean ABPI improvement was 0.01 (P=0.439), mean HbA1c reduction was 0.51% (P<0.05), mean total cholesterol (TC) increase was 0.36 mmol/l (P<0.05), mean high-density lipoprotein cholesterol (HDL-C) increase was 0.15 mmol/l (P<0.05) and mean low-density lipoprotein cholesterol increased by 0.19 mmol/l (P=0.098). Rosiglitazone significantly improved plasminogen activity. There was also significant HbA1c reduction, and rise in both TC and HDL-C. Thus, rosiglitazone potentially improves the atherosclerotic burden and prothrombotic state. In future, more studies are needed to confirm the relationship between rosiglitazone, fibrinolytic system and atheromatous reduction in type 2 diabetes mellitus.
OBJECTIVE: To investigate whether pharmacological interventions with rosiglitazone/ramipril can reverse preclinical vasculopathy in newly diagnosed untreated patients with type 2 diabetes (T2DM) and impaired glucose tolerance (IGT).
METHODS: In this randomised, double-blind, placebo-controlled study, 33 T2DM and 33 IGT patients were randomised to 4 mg rosiglitazone or 5 mg ramipril or placebo for 1 year. The subjects were newly diagnosed, untreated, normotensive, nonobese, nonsmoker, and nonhyperlipidaemic. Haemodynamic variables were measured at three treatment phases and pulse wave velocity (PWV) and augmentation index (AI) were measured throughout the treatment period.
RESULTS: Rosiglitazone showed a significant reduction in PWV (p=0.039) and AI (p=0.031) and ramipril demonstrated a significant reduction of AI (p=0.025) in IGT in comparison to placebo on the 12th month of treatment. No significant difference was observed in PWV and AI in T2DM with rosiglitazone/ramipril in comparison to placebo during overall treatment period.
CONCLUSIONS: Rosiglitazone significantly reversed preclinical vasculopathy in IGT as evident by significant decrease in PWV and AI after 1 year of treatment. Ramipril also reduced large artery stiffness as shown by significant decrease of AI after 1 year of treatment in IGT. Further trials are needed for a longer period of time, maybe with higher doses, to show whether rosiglitazone/ramipril can reverse preclinical vasculopathy in T2DM.