title: Histological remodeling in an ovine heart failure model resembles human ischemic cardiomyopathy.
abstract: Staged coronary embolization, causing myocardial microinfarctions, has been shown in dogs and sheep to cause chronic ischemic heart failure (HF) that resembles the hemodynamics of the human condition. However, its histopathological basis remains unclear. We examined the hypothesis that the ventricular remodeling seen in such sheep resembles the histopathology of human ischemic cardiomyopathy (ICM). Understanding the pathophysiology of this model will determine its place in the development of treatment strategies for HF. Global left ventricular (LV) damage resulting in HF was induced by staged coronary embolization in 11 sheep. Six others served as controls (normal control, NC). In HF sheep, the heart was harvested 6 months after LV ejection fraction (EF) had stabilized at <35%. Histopathological profiles were compared in biventricular transverse sections at midpapillary level using computed image analysis. LV end-diastolic volume increased in the HF group from 84.9+/-29 to 122.4+/-30.3 ml (n=11, P<.05), but myocytes across the LV wall in noninfarcted zones decreased (435.7+/-38.2 NC; 297.8+/-48.4/unit area HF; n=11, P<.0001) as did myocyte nuclear density (990.5+/-51.5 NC; 677.5+/-121.1/mm(2) HF, n=11, P<.0001). In contrast, LV replacement and interstitial fibrosis increased as did myocyte diameter in noninfarcted zones: 0.1+/-0.1 to 6.2+/-4.5% (P=.0049); 2.0+/-1.0 to 7.6+/-4.9% (P=.0149); and 10.0+/-0.5 to 15.9+/-2.2 microm (P<.0001), respectively. Although LV myocyte nuclear length increased (10.2+/-1.0 NC; 12.2+/-0.9 microm HF, n=11, P=.0006), right ventricular (RV) myocyte nuclear density and length did not alter. In this ovine chronic HF model, LV dilation and interstitial and myocyte remodeling resemble human ICM.
authors.affiliation: Department of Pathology, National Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan. yikeda@hsp.ncvc.go.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Ikeda
authors.forename: C
authors.initials: C
authors.lastname: Yutani
authors.forename: Y
authors.initials: Y
authors.lastname: Huang
authors.forename: K
authors.initials: K
authors.lastname: Masuda
authors.forename: T
authors.initials: T
authors.lastname: Yuasa
authors.forename: O
authors.initials: O
authors.lastname: Kawaguchi
authors.forename: S N
authors.initials: SN
authors.lastname: Hunyor
mesh_terms: D000818:Animals; D001835:Body Weight; D004195:Disease Models, Animal; D004452:Echocardiography; D005355:Fibrosis / Q000473:pathology; D006333:Heart Failure / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008863:Microspheres; D017202:Myocardial Ischemia / Q000473:pathology* / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology; D009929:Organ Size; D012756:Sheep; D013045:Species Specificity; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology; D020257:Ventricular Remodeling