Publication Date:
2011-11-18
Description:
Abstract 4809 Background. Mesenchymal Stem Cells (MSC) are among major players of the hematopoietic niche. In addition, they have shown to be useful in clinical studies both as immune-modulators as well as in regenerative medicine. However, a major obstacle for proving their usefulness is to obtain a clinically effective cell dose, since often less than 10̂6 /kg of adult MSC have been used. Thus, their potential efficacy can be either disregarded or not formally proved. In addition, forcing in vitro the proliferative potential of adult BM derived MSC (BM-MSC) implies the risk of generating chromosomal abnormalities. The aim of the study is to investigate the potential use of fetal derived MSC (FT-MSC) which could provide means to overcome the above limits. In addition, we attempted to identify some molecular mechanisms regulating the proliferative potential of FT-MSC and their supportive capacity of hematopoietic progenitors. Methods: Specimens from 5 fetal samples were collected after mechanically induced abortion (median gestational age 11 weeks). FT-MSC were obtained from kidneys and femurs and adult MSC from normal BM. After 15 days of culture adherent cells were sub-cultured until 80% confluence. Immunophenotype and karyotype were evaluated. The telomere length was evaluated using the Telomere PNA system. FT-MSC were injected into NOD/SCID mice to rule out any tumorigenic potential. The immunosuppressive activity of FT-MSC and adult BM-MSC was evaluated by standard assays. To quantify the supportive capacity of FT-MSC we weekly measured the colony output using normal BM MNC layered over confluent FT-MSC compared to stromal cell line MS-5 and to BM-MSC. Protein expression of the key regulators of Hedgehog and Wnt pathways were investigated in FT-MSC and BM-MSC by immunofluorescence using monoclonal antibodies against Indian Hedghog (IHh), Sonic Hedgehog (SHh), Desert Hedgehog (DHh) and b-catenin. Fluorescent signal was detected by confocal microscope. Results. MSC successfully grew from 100% of fetal samples. FT-MSC maintained the typical MSC markers (CD73, CD105, CD44, CD106, CD166, HLA class I, negative for HLA class II) and possessed the same capacity to inhibit T cell proliferation as BM-MSC. FT-MSC compared to adult BM-MSC showed a higher proliferative potential: they reached the fifteenth generation and had a median cumulative population doubling of 26 (range 4–47) while BM-MSC grew until the sixth passage showing a median cumulative population doubling of 4 (range 2–5) (p
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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