Umbilical cord blood-derived stem cells spontaneously express cardiomyogenic traits.
BACKGROUND
Umbilical cord blood (UCB) has been widely used for hematopoietic stem cell transplantation. The UCB-derived stem cells (UCBSCs) have been proposed as an alternative to bone marrow (BM)-derived mesenchymal stem cells (MSCs) for cardiac cell-based therapy. Herein we studied whether UCBSCs spontaneously exhibit cardiac-specific markers in vitro.


METHODS
Human UCBSCs were isolated, expanded, and phenotyped by flow cytometry, quantitative RT-PCR, and immunofluorescence. Cell pluripotency and proliferation were also assessed by adipogenic and osteogenic media and in growth assays.


RESULTS
Among 25 analyzed UCB, 16% of cases afforded primary culture satisfactory generation of UCBSCs. Duplication time (Td) of cultures was 2.16 +/- 0.06 days. The cells were strongly positive for CD105 (18.5 +/- 0.14), CD44 (27 +/- 2.8), CD166 (13 +/- 9), CD29 (59 +/- 9.4), CD90 (60 +/- 11) and consistently negative for CD117 (1.2 +/- 0.1), CD106 (1.1 +/- 0), CD34 (1.2 +/- 0.2), CD14 (1 +/- 0), and CD45 (1 +/- 0), consistent with a mesenchymal lineage. Adipogenesis and osteogenesis of cells resulted in low accumulation of intracellular lipid droplets and high deposition of calcium. The UCBSCs showed gene transcripts for alpha-actinin, connexin (Cx)-43, SERCA-2, and stromal cell-derived factor (SDF)-1alpha. At the protein level, the cells abundantly expressed alpha-actinin, Cx-43, SERCA-2 and SDF-1alpha. In contrast, these cells did not express the cardiac transcription factors GATA-4, Tbx5, and Nkx2.5, nor the sarcomeric proteins beta-myosin heavy chain (beta-MyHC) or cardiac troponin I (cTnI).


CONCLUSIONS
Human UCBSCs may represent an alternative source of stem cells for myocardial-cell replacement. These cells can be highly expanded. They spontaneously express proteins of paramount importance for cardiovascular regeneration, such as Cx-43, SERCA-2, and SDF-1alpha.
Prat-Vidal
C
C
Laboratory of Cell Physiology, Department of Cardiology-Institut Català de Ciències Cardiovasculars (ICCC) Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain.
Roura
S
S
Farré
J
J
Gálvez
C
C
Llach
A
A
Molina
C E
CE
Hove-Madsen
L
L
Garcia
J
J
Cinca
J
J
Bayes-Genis
A
A
D000328:Adult; D001854:Bone Marrow Cells / Q000166:cytology; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation / Q000502:physiology*; D036101:Cord Blood Stem Cell Transplantation / Q000379:methods*; D005312:Fetal Blood / Q000166:cytology*; D006321:Heart / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D008648:Mesoderm / Q000166:cytology; D009206:Myocardium / Q000166:cytology*; D010641:Phenotype; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology*; D016896:Treatment Outcome