Timing of bone marrow cell delivery has minimal effects on cell viability and cardiac recovery after myocardial infarction.
BACKGROUND
Despite ongoing clinical trials, the optimal time for delivery of bone marrow mononuclear cells (BMCs) after myocardial infarction is unclear. We compared the viability and effects of transplanted BMCs on cardiac function in the acute and subacute inflammatory phases of myocardial infarction.


RESULTS
The time course of acute inflammatory cell infiltration was quantified by FACS analysis of enzymatically digested hearts of FVB mice (n=12) after left anterior descending artery ligation. Mac-1(+)Gr-1(high) neutrophil infiltration peaked at day 4. BMCs were harvested from transgenic FVB mice expressing firefly luciferase (Fluc) and green fluorescent protein (GFP). Afterward, 2.5x10(6) BMCs were injected into the left ventricle of wild-type FVB mice either immediately (acute BMC) or 7 days (subacute BMC) after myocardial infarction, or after a sham procedure (n=8 per group). In vivo bioluminescence imaging showed an early signal increase in both BMC groups at day 7, followed by a nonsignificant trend (P=0.203) toward improved BMC survival in the subacute BMC group that persisted until the bioluminescence imaging signal reached


BACKGROUND
<0.01) and 6 weeks (both BMC groups versus saline; P<0.05) but no significant differences between the 2 BMC groups. FACS analysis of BMC-injected hearts at day 7 revealed that GFP(+) BMCs expressed hematopoietic (CD45, Mac-1, Gr-1), minimal progenitor (Sca-1, c-kit), and no endothelial (CD133, Flk-1) or cardiac (Trop-T) cell markers.


CONCLUSIONS
Timing of BMC delivery has minimal effects on intramyocardial retention and preservation of cardiac function. In general, there is poor long-term engraftment and BMCs tend to adopt inflammatory cell phenotypes.
Swijnenburg
Rutger-Jan
RJ
Department of Cardiothoracic Surgery, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, USA.
Govaert
Johannes A
JA
van der Bogt
Koen E A
KE
Pearl
Jeremy I
JI
Huang
Mei
M
Stein
William
W
Hoyt
Grant
G
Vogel
Hannes
H
Contag
Christopher H
CH
Robbins
Robert C
RC
Wu
Joseph C
JC
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001854:Bone Marrow Cells / Q000378:metabolism; D016026:Bone Marrow Transplantation; D002454:Cell Differentiation; D002470:Cell Survival; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005260:Female; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D006410:Hematopoiesis; D007249:Inflammation / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D018836:Inflammation Mediators / Q000378:metabolism; D049409:Luciferases, Firefly / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D020556:Neutrophil Infiltration; D010641:Phenotype; D020127:Recovery of Function; D013997:Time Factors; D014463:Ultrasonography; D016277:Ventricular Function, Left
D015415:Biomarkers; D018836:Inflammation Mediators; D049452:Green Fluorescent Proteins; D049409:Luciferases, Firefly