p38 mitogen-activated protein kinase inhibition improves cardiac function and attenuates left ventricular remodeling following myocardial infarction in the rat.
OBJECTIVE
The aim of this study was to examine the effect of the p38 mitogen-activated protein kinase (MAPK) inhibitor, RWJ-67657 (RWJ), on left ventricular (LV) dysfunction and remodeling post-myocardial infarction (MI) in rats.


BACKGROUND
p38 MAPK signaling has been implicated in the progression of chronic heart failure.


METHODS
From day 7 post-MI (coronary artery ligation), rats received either RWJ (50 mg/day, by gavage, n = 8, MI+RWJ) or vehicle (by gavage, n = 8, MI+V) for 21 days. Echocardiography was performed on day 6, before the commencement of treatment, and on day 27. In vivo hemodynamic measurements were made on day 28. Sham-operated rats served as controls.


RESULTS
The LV end-diastolic pressure and lung/body weight ratio were reduced, whereas the maximum rate of rise of LV pressure was increased towards sham levels in MI+RWJ compared with MI+V. Baseline echocardiographic studies demonstrated uniform LV remodeling and dysfunction in MI rats. Fractional shortening (FS) further deteriorated in MI+V, whereas FS was preserved in MI+RWJ. Progressive LV dilation and infarct expansion observed in MI+V were inhibited in MI+RWJ. MI+RWJ also demonstrated increased myocyte hypertrophy in the peri-infarct and non-infarct zones, and reduced myocardial collagen and alpha-smooth muscle actin (SMA) immunoreactivity compared with MI+V. The antifibrotic effects of RWJ in vivo may reflect direct effects on cardiac fibroblasts, because RWJ attenuated transforming growth factor beta-1-stimulated collagen synthesis and alpha-SMA expression in isolated cardiac fibroblasts. RWJ also protected cultured myocytes from hydrogen peroxide-induced apoptosis.


CONCLUSIONS
RWJ-67657 treatment post-MI had beneficial effects on LV remodeling and dysfunction, supporting a key role for p38 MAPK in pathologic cell signaling in these processes and its inhibition as a novel therapy.
National Health and Medical Research Council Center of Clinical Research Excellence in Therapeutics, Department of Medicine, Monash University, Alfred Hospital, Commercial Road, Prahran, Victoria 3181, Australia.
Fiona
F
See
Walter
W
Thomas
Kerrie
K
Way
Alex
A
Tzanidis
Andrew
A
Kompa
Dion
D
Lewis
Silviu
S
Itescu
Henry
H
Krum
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism; D024043:Collagen Type II / Q000378:metabolism; D004452:Echocardiography; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D007093:Imidazoles / Q000494:pharmacology*; D007124:Immunoenzyme Techniques; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology; D009203:Myocardial Infarction / Q000473:pathology / Q000503:physiopathology*; D009206:Myocardium / Q000473:pathology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D011725:Pyridines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000473:pathology / Q000503:physiopathology; D020257:Ventricular Remodeling / Q000187:drug effects* / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000502:physiology
D024042:Collagen Type I; D024043:Collagen Type II; D004791:Enzyme Inhibitors; D007093:Imidazoles; D011725:Pyridines; C400277:RWJ 67657; D048051:p38 Mitogen-Activated Protein Kinases