Assessment of in vitro aging of mesenchymal stem cell

Mesenchyml stem cell (MSC) are receiving much attention in treatment of various diseases. The low frequency of MSCs in bone marrow (BM) necessitates their in vitro expansion prior to clinical use. We evaluated the effect of long term culture on the senescence of these cells."nBM cells were taken from 11 transplant donors with mean age of 25 years. In different passages, MSC were examined for different aging indicators including: telomere length assay, differentiation ability, immunophenotyping of CD13, CD44 and CD34 antigens, determination of cumulative population dou¬blings (CPDs), and study of morphological characteristics of MSC cultures."nThe mean long term culture was 118 day and the mean passage number was 9. The average number of PD decreased from 7.7 to 1.2 in the 10th passage. The mean telomere length decreased from 9.19 Kbp to 8.7 kbp in the 9th passage. Differentiation potential dropped from the 6th passage on. The culture's morphological abnormalities were typical of the Hayflick model of cellular aging. We believe that MSC enter senescence almost undetectably from the moment of in vitro culturing. Si¬multaneously these cells are losing their stem cell characteristics. Therefore, it is much better to con¬sider them for cell and gene therapy early on

The Effect Of 8 Day Storage At 4˚C On Total Nucleated Cell Count, Cell Viability, And Granulocyte-Macrophage Colony Forming Unit Of Mobilized Peripheral Blood

Background: Hematopoietic stem cell (HSC) transplantation has brought the possibility of the use of high dose chemotherapy in the treatment of malignant hematopoietic diseases. Short-term HSC preservation at 4˚C is the most common method for autologous peripheral blood stem cell transplantation (PBSCT). Materials and Methods: Thirty-seven mobilized PBSC samples from thirteen hematological patients (4 AML, 4 MM and 5 Lymphoma cases) who were selected for autologous PBSCT and 24 normal candidates for allogenic PBSCT were preserved in five separate sterile 2 ml tubes in 4˚C. Each sample was evaluated for total nucleated cell (TNC) count, dye exclusion cell viability and Granulocyte-Macrophage colony forming unit (GM-CFU; in semisolid medium after 16 days) in days 0, 2, 4, 6 and 8. The results were converted to percentages of day 0 measures. The data were analyzed by SPSS 10.0 using Paired Samples T test, Independent Samples T test and Regression. Results: The mean percentages (and standard deviations) of TNC count, cell viability and GM-CFU for days 0, 2, 4, 6 and 8 are shown below: No significant correlation was found between age, sex, weight and the kind of donor with TNC, viability and GM-CFU. Conclusion: In this study, we have found that during storage of mobilized PBSC in 4˚C, TNC count and cell viability still remains higher than 70% after eight days, while GM-CFU decreases more rapidly and falls to less than 50% after day 4.Therefore, TNC count and cell viability do not decrease as fast as GM-CFU