Generation of mesenchymal stromal cells in the presence of platelet lysate: a phenotypic and functional comparison of umbilical cord blood- and bone marrow-derived progenitors.
BACKGROUND
Mesenchymal stromal cells are employed in various different clinical settings in order to modulate immune response. However, relatively little is known about the mechanisms responsible for their immunomodulatory effects, which could be influenced by both the cell source and culture conditions.


METHODS
We tested the ability of a 5% platelet lysate-supplemented medium to support isolation and ex vivo expansion of mesenchymal stromal cells from full-term umbilical-cord blood. We also investigated the biological/functional properties of umbilical cord blood mesenchymal stromal cells, in comparison with platelet lysate-expanded bone marrow mesenchymal stromal cells.


RESULTS
The success rate of isolation of mesenchymal stromal cells from umbilical cord blood was in the order of 20%. These cells exhibited typical morphology, immunophenotype and differentiation capacity. Although they have a low clonogenic efficiency, umbilical cord blood mesenchymal stromal cells may possess high proliferative potential. The genetic stability of these cells from umbilical cord blood was demonstrated by a normal molecular karyotype; in addition, these cells do not express hTERT and telomerase activity, do express p16(ink4a) protein and do not show anchorage-independent cell growth. Concerning alloantigen-specific immune responses, umbilical cord blood mesenchymal stromal cells were able to: (i) suppress T- and NK-lymphocyte proliferation, (ii) decrease cytotoxic activity and (iii) only slightly increase interleukin-10, while decreasing interferon-gamma secretion, in mixed lymphocyte culture supernatants. While an indoleamine 2,3-dioxygenase-specific inhibitor did not reverse mesenchymal stromal cell-induced suppressive effects, a prostaglandin E(2)-specific inhibitor hampered the suppressive effect of both umbilical cord blood- and bone marrow-mesenchymal stromal cells on alloantigen-induced cytotoxic activity. Mesenchymal stromal cells from both sources expressed HLA-G.


CONCLUSIONS
Umbilical cord blood- and bone marrow-mesenchymal stromal cells may differ in terms of clonogenic efficiency, proliferative capacity and immunomodulatory properties; these differences may be relevant for clinical applications.
Oncoematologia Pediatrica, Fondazione IRCCS Policlinico San Matteo, Università di Pavia, Pavia, Italy.
Maria Antonietta
MA
Avanzini
Maria Ester
ME
Bernardo
Angela Maria
AM
Cometa
Cesare
C
Perotti
Nadia
N
Zaffaroni
Francesca
F
Novara
Livia
L
Visai
Antonia
A
Moretta
Claudia
C
Del Fante
Raffaella
R
Villa
Lynne M
LM
Ball
Willem E
WE
Fibbe
Rita
R
Maccario
Franco
F
Locatelli
D015703:Antigens, CD / Q000032:analysis; D001792:Blood Platelets / Q000737:chemistry* / Q000166:cytology; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000166:cytology; D002454:Cell Differentiation / Q000187:drug effects; D002457:Cell Extracts / Q000737:chemistry / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D003602:Cytotoxicity, Immunologic / Q000276:immunology; D005260:Female; D005312:Fetal Blood / Q000166:cytology; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology; D059630:Mesenchymal Stem Cells / Q000166:cytology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D019098:Telomerase / Q000235:genetics
D015703:Antigens, CD; D002457:Cell Extracts; D019941:Cyclin-Dependent Kinase Inhibitor p16; C509186:TERT protein, human; D019098:Telomerase