Human mesenchymal stem cells from chorionic villi and amniotic fluid are not susceptible to transformation after extensive in vitro expansion.

Mesenchymal stem cells (MSCs) are promising candidates for cell therapy and tissue engineering. Increasing evidence suggests that MSCs isolated from fetal tissues are more plastic and grow faster than adult MSCs. In this study, we characterized human mesenchymal progenitor cells from chorionic villi (CV) and amniotic fluid (AF) isolated during the first and second trimesters, respectively, and compared them with adult bone marrow-derived MSCs (BM). We evaluated 10 CV, 10 AF, and 6 BM samples expanded until the MSCs reached senescence. We used discarded cells from prenatal analyses for all the experiments. To evaluate the replicative stability of these cells, we studied the telomerase activity, hTERT gene transcription, and telomere length in these cells. Spontaneous chromosomal alterations were excluded by cytogenetic analysis. We studied the expression of c-myc and p53, tumor-associated genes, at different passage in culture and the capacity of these cells to grow in an anchorage-independent manner by using soft agar assay. We isolated homogeneous populations of spindle-shaped CV, AF, and BM cells expressing mesenchymal immunophenotypic markers throughout the period of expansion. CV cells achieved 14 ± 0.9 logs of expansion in 118 days and AF cells achieved 21 ± 0.9 logs in 118 days, while BM cells achieved 11 × 0.4 logs in 84 days. Despite their high proliferation capacity, fetal MSCs showed no telomerase activity, no hTERT and c-myc transcriptions, and maintained long, stable telomeres. A constant expression level of p53 and a normal karyotype were preserved throughout long-term expansion, suggesting the safety of fetal MSCs. In conclusion, our results indicate that fetal MSCs could be an alternative, more accessible resource for cell therapy and regenerative medicine

Molecular and functional characterization of human bone marrow adipocytes

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Telomere length, c-myc and mad-1 expression could represent prognosis markers of myelodysplastic syndrome

tTelomere dysfunction might generate genomic instability leading to the progression of myelodysplasticsyndromes (MDS) into acute myeloid leukemia (AML). We investigated telomere length (TL), telome-rase activity (TA) and hTERT, c-myc, mad1, and p53 expression in the bone marrow of patients withMDS (n = 109), AML (n = 47) and in controls (n = 24). TL was lower in MDS patients than in controls(p < 0.001) and higher in L-MDS (low, intermediate-1 IPSS, p < 0.01) respect H-MDS (high, intermediate-2IPSS, p < 0.01) patients. Mad-1 expression was higher in MDS patients than in controls (p < 0.01), c-mycexpression was highest in AML and in H-MDS patients. Our results show that the telomere dynamicsmight be useful for stratifying patients according to a risk scoring system