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

Carbon capture with molten carbonate fuel cells: Experimental tests and fuel cell performance assessment

Molten carbonate fuel cells (MCFCs) may operate as CO2 separators and concentrators while generating electric power, being thus a very interesting candidate to be used as carbon capture systems in fossil fired power plants.The main aim of this work is to understand the MCFC performance, its potential and efficiency to separate CO2 from the exhaust gas of fossil fired power plants and the effect of critical parameters such as the cathodic carbon dioxide concentration (XCO2) and utilization (UCO2), as well as the partial pressure ratio between oxygen and carbon dioxide (PO2/PCO2) and other parameters such as the oxygen concentration (XO2), utilization (UO2) and the total cathodic flow rate (Qcat). This was achieved by studying the experimental behaviour of a single MCFC when it is fed with a mixture simulating the composition of the exhaust gases of a combined heat and power plant, in order to point out potential limitations in the fuel cell operating conditions.In particular, the carbon dioxide concentration in the cathodic section was shown to be a critical factor at low values, that can both induce quick voltage drops and make the cell sensitive to the other parameters, which are otherwise not so important