Peroxisome proliferator-activated receptor alpha-independent actions of fenofibrate exacerbates left ventricular dilation and fibrosis in chronic pressure overload.
Progressive cardiac remodeling is characterized by subsequent chamber hypertrophy, enlargement, and pump dysfunction. It is also associated with increased cardiac fibrosis and matrix turnover. Interestingly, peroxisome proliferator-activated receptor (PPAR) alpha activators reduce cardiac hypertrophy, inflammation, and fibrosis. Little is known about the role of fenofibrates in mediating PPARalpha-independent effects in response to chronic pressure overload (PO). Wild-type and PPARalpha-deficient mice were subjected to chronic PO caused by ascending aortic constriction to test the role of fenofibrates in chronic, progressive cardiac remodeling by a PPARalpha-independent mechanism. Mice were randomized to regular chow or chow-containing fenofibrate (100 mg/kg of body weight per day) for 1 week before and 8 weeks after ascending aortic constriction. In the presence of PPARalpha, wild-type chronic PO mice, treated with fenofibrate, had improved cardiac remodeling. However, PO PPARalpha-deficient mice treated with fenofibrate had increased mortality, significantly adverse left ventricular end diastolic (3.4+/-0.1 versus 4.2+/-0.1 mm) and end systolic (1.5+/-0.2 versus 2.5+/-0.2 mm) dimensions, and fractional shortening (57+/-3% versus 40+/-3%). Fenofibrate also increased myocardial hypertrophy, cardiac fibrosis, and the ratio of matrix metalloproteinase-2/tissue inhibitor of matrix metalloproteinase-2 in PO PPARalpha-deficient mice. Fenofibrate inhibited matrix metalloproteinase activity in vitro and aldosterone-induced increases in extracellular signal-regulated kinase phosphorylation. Thus, fenofibrate improved cardiac remodeling in chronic PO mice. However, in PPARalpha-deficient mice, this chronic PO was exacerbated and associated with increased myocardial fibrosis and altered matrix remodeling. In the absence of PPARalpha, fenofibrates exerts deleterious, pleiotropic myocardial actions. This is an important observation, because PPARalpha agonists are considered possible inhibitory regulators of cardiac remodeling in the remodeled heart.
Duhaney
Toni-Ann S
TA
Whitaker Cardiovascular Institute, Boston University School of Medicine, MA 02118, USA.
Cui
Lei
L
Rude
Mary K
MK
Lebrasseur
Nathan K
NK
Ngoy
Soeun
S
De Silva
Deepa S
DS
Siwik
Deborah A
DA
Liao
Ronglih
R
Sam
Flora
F
D000450:Aldosterone / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D002908:Chronic Disease; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D011345:Fenofibrate / Q000494:pharmacology*; D005355:Fibrosis; D006973:Hypertension / Q000401:mortality / Q000473:pathology / Q000503:physiopathology*; D000960:Hypolipidemic Agents / Q000494:pharmacology*; D053208:Kaplan-Meier Estimate; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors; D051379:Mice; D008815:Mice, Inbred Strains; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000201:enzymology; D047493:PPAR alpha / Q000172:deficiency / Q000378:metabolism*; D047492:Peroxisome Proliferator-Activated Receptors / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D013997:Time Factors; D019714:Tissue Inhibitor of Metalloproteinases / Q000378:metabolism; D016277:Ventricular Function, Left / Q000187:drug effects*
D000960:Hypolipidemic Agents; D061965:Matrix Metalloproteinase Inhibitors; D047493:PPAR alpha; D047492:Peroxisome Proliferator-Activated Receptors; D019714:Tissue Inhibitor of Metalloproteinases; D000450:Aldosterone; D048049:Extracellular Signal-Regulated MAP Kinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D011345:Fenofibrate