Pharmacogenomic, physiological, and biochemical investigations on safety and efficacy biomarkers associated with the peroxisome proliferator-activated receptor-gamma activator rosiglitazone in rodents: a translational medicine investigation.

Peroxisome proliferator-activated receptor (PPAR)-gamma modulators, a class of antidiabetic drugs, have been associated with cardiovascular risks in type 2 diabetes in humans. The objective of this study was to explore possible cardiovascular risk biomarkers associated with PPAR-gamma in rodents that could provide an alert for risk to humans. Normal, myocardial infarction-induced heart failure (HF) or Zucker diabetic fatty (ZDF) rats were used. Rats (n = 5-6) were treated with either vehicle or rosiglitazone (RGZ; 3 or 45 mg/kg/day p.o.) for 4 weeks. Biomarkers for potential cardiovascular risks were assessed, including 1) ultrasound for cardiac structure and function; 2) neuroendocrine and hormonal plasma biomarkers of cardiovascular risk; 3) pharmacogenomic profiling of cardiac and renal tissue by targeted tissue low-density gene array representing ion channels and transporters, and components of the renin-angiotensin-aldosterone system; and 4) immunohistochemistry for cardiac fibrosis, hypertrophy, and inflammation (macrophages and tumor necrosis factor-alpha). HF was confirmed by increase in cardiac brain natriuretic peptide expression (p < 0.01) and echocardiography. Adequate exposure of RGZ was confirmed by pharmacokinetics (plasma drug levels) and the pharmacodynamic biomarker adiponectin. In normal or HF rats, RGZ had no negative effects on any of the biomarkers investigated. Similarly, RGZ had no significant effects on gene expression except for the increase in interleukin-6 mRNA expression in the heart and decrease in epithelial sodium channel beta in the kidney. In contrast, echocardiography showed improved cardiac structure and function after RGZ in ZDF rats. Taken together, this study suggests a limited predictive power of these preclinical models in respect to observed clinical adverse effects associated with RGZ.

Peroxisome proliferator-activated receptor alpha and alpha/gamma agonists do not cause impairment in renal function in the rat.

BACKGROUND/AIMS: Patients treated with peroxisome proliferator-activated receptor analogs (PPAR) alpha or alpha/gamma may develop a transient and reversible increase in serum creatinine, the mechanism of which remains obscure. This study evaluates whether treatment with either PPAR-alpha or -alpha/gamma analogs, fenofibrate or tesaglitazar, may cause deterioration in renal hemodynamics or exert direct tubular or glomerular nephrotoxic effects in rats. METHODS: Male Sprague-Dawley rats (300-320 g) were treated per os with fenofibrate (300 mg/kg/day), tesaglitazar (1.2 mg/kg/day) or vehicle, for 14 days. Glomerular filtration rate (GFR) and renal blood flow (RBF) were measured by inulin clearance and ultrasonic flowmetry, and cumulative excretion of sodium and creatinine were assessed. Biomarkers of glomerular and tubular injury were measured, including urinary albumin excretion and renal mRNA levels of kidney injury molecule 1 (Kim-1), lipocalin 2 (Lcn2), and osteopontin (Spp1). RESULTS: Fenofibrate and tesaglitazar improved the lipid profile, but caused no detectable decrease in GFR or RBF compared with vehicle-treated rats. Furthermore, the cumulative excretions of sodium and creatinine were not altered by the drugs. Finally, there was no significant difference between drug- and vehicle-treated groups in urinary albumin excretion or in the expression of renal injury biomarkers. CONCLUSIONS: In the rat, no direct nephrotoxic effect or deterioration in renal hemodynamics and function were observed following treatment with fenofibrate or tesaglitazar.