Human cardiac mesoangioblasts isolated from hypertrophic cardiomyopathies are greatly reduced in proliferation and differentiation potency.
OBJECTIVE
Our objective was to test whether progenitor cell proliferation and differentiation potential may vary depending upon the disease of the donor.


RESULTS
Human cardiac mesoangioblasts were isolated from cardiac muscle biopsies of patients undergoing open heart surgery for correction of mitral regurgitation following an acute myocardial infarction (MR-MI) or correction of mitral and aortic regurgitation with ensuing left ventricular hypertrophy (MAR-LVH). The cells express surface markers and cardiac genes similar to mouse cardiac mesoangioblasts; they have limited self-renewing and clonogenic activity and are committed mainly to cardiogenesis. Although cardiac differentiation can be induced by 5-azacytidine or by co-culture with rat neonatal cardiomyocytes, human cells do not contract spontaneously like their mouse counterparts. When locally injected in the infarcted myocardium of immunodeficient mice, cardiac mesoangioblasts generate a chimeric heart that contains human myocytes and some capillaries; likewise, they colonize chick embryo hearts when transplanted in ovo. At variance with cells from patients with MR-MI, when isolation was performed on biopsies from MAR-LVH, cells could be isolated in much lower numbers, proliferated less extensively and failed to differentiate.


CONCLUSIONS
Cardiac mesoangioblasts are present in the human heart but this endogenous progenitor population is progressively exhausted, possibly by continuous and inefficient regeneration attempts.
Gálvez
Beatriz G
BG
Division of Regenerative Medicine, San Raffaele Scientific Institute, 58 Via Olgettina, 20132 Milan, Italy. bggalvez@hotmail.com
Covarello
Diego
D
Tolorenzi
Rosanna
R
Brunelli
Silvia
S
Dellavalle
Arianna
A
Crippa
Stefania
S
Mohammed
Salman Afroze Azmi
SA
Scialla
Ludovica
L
Cuccovillo
Ivan
I
Molla
Fabiola
F
Staszewsky
Lidia
L
Maisano
Francesco
F
Sampaolesi
Maurilio
M
Latini
Roberto
R
Cossu
Giulio
G
D053687:Adult Stem Cells / Q000473:pathology* / Q000637:transplantation; D000818:Animals; D001022:Aortic Valve Insufficiency / Q000473:pathology; D002312:Cardiomyopathy, Hypertrophic / Q000473:pathology*; D002454:Cell Differentiation; D049109:Cell Proliferation; D002469:Cell Separation; D002478:Cells, Cultured; D002642:Chick Embryo; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D008944:Mitral Valve Insufficiency / Q000473:pathology; D009203:Myocardial Infarction / Q000473:pathology / Q000628:therapy; D009206:Myocardium / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000473:pathology; D051381:Rats; D033581:Stem Cell Transplantation