title: Aging Kit mutant mice develop cardiomyopathy.
abstract: Both bone marrow (BM) and myocardium contain progenitor cells expressing the c-Kit tyrosine kinase. The aims of this study were to determine the effects of c-Kit mutations on: i. myocardial c-Kit(+) cells counts and ii. the stability of left ventricular (LV) contractile function and structure during aging. LV structure and contractile function were evaluated (echocardiography) in two groups of Kit mutant (W/Wv and W41/W42) and in wild type (WT) mice at 4 and 12 months of age and the effects of the mutations on LV mass, vascular density and the numbers of proliferating cells were also determined. In 4 month old Kit mutant and WT mice, LV ejection fractions (EF) and LV fractional shortening rates (FS) were comparable. At 12 months of age EF and FS were significantly decreased and LV mass was significantly increased only in W41/W42 mice. Myocardial vascular densities and c-Kit(+) cell numbers were significantly reduced in both mutant groups when compared to WT hearts. Replacement of mutant BM with WT BM at 4 months of age did not prevent these abnormalities in either mutant group although they were somewhat attenuated in the W/Wv group. Notably BM transplantation did not prevent the development of cardiomyopathy in 12 month W41/W42 mice. The data suggest that decreased numbers and functional capacities of c-Kit(+) cardiac resident progenitor cells may be the basis of the cardiomyopathy in W41/W42 mice and although defects in mutant BM progenitor cells may prove to be contributory, they are not causal.
authors.affiliation: Leilihei Heart Institute, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America.
authors.forename: Lei
authors.initials: L
authors.lastname: Ye
authors.forename: Eric Yang
authors.initials: EY
authors.lastname: Zhang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Xiong
authors.forename: Clinton M
authors.initials: CM
authors.lastname: Astle
authors.forename: Pengyuan
authors.initials: P
authors.lastname: Zhang
authors.forename: Qinglu
authors.initials: Q
authors.lastname: Li
authors.forename: Arthur H L
authors.initials: AH
authors.lastname: From
authors.forename: David E
authors.initials: DE
authors.lastname: Harrison
authors.forename: Jianyi Jay
authors.initials: JJ
authors.lastname: Zhang
mesh_terms: D000375:Aging / Q000235:genetics / Q000473:pathology*; D000704:Analysis of Variance; D000818:Animals; D016026:Bone Marrow Transplantation; D009202:Cardiomyopathies / Q000235:genetics / Q000473:pathology*; D002452:Cell Count; D004452:Echocardiography; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006352:Heart Ventricles / Q000166:cytology / Q000201:enzymology / Q000503:physiopathology*; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009154:Mutation / Q000235:genetics; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D013599:Systole / Q000235:genetics / Q000502:physiology*
chemical_list: D049452:Green Fluorescent Proteins; D019009:Proto-Oncogene Proteins c-kit