10. Cryopreservation and banking

From all the previous studies, it becomes clear that the use of hMSCs in clinical field will increase in future. For clinical applications, a large number of MSCs in an 'off the shelf' format is required. For this purpose, cryopreservation and banking are necessary to be established. This will allow unique opportunities to improve the potential uses of these cells in research and clinical applications. Keeping in mind its use in future clinical and therapeutic applications, there is a need to ensure the safety and efficacy of these cells while cryopreserving and banking. Cryopreservation media should be optimal so uniform change in temperature during freezing and thawing, long-term storage in liquid nitrogen and employed freezing device are the main factors to consider.

In the cryopreservation media in which cells can maintain their stem cells abilities for long time, the cells require a source of their nutrients as the animal base reagent, like FBS, but previous studies have showed that there is difficulty in removing animal proteins from the hMSCs and that may elicit adverse reactions in the patients who receive these cells for treatment [89]. Therefore, a serum-free media is alternative for the cryopreservation of MSCs and it was successfully used [90]. Lately, instead of using FBS, human albumin and neuropeptide were used. It was observed that MSCs maintained their proliferation potential and cell survival in the culture conditions. Moreover, cryoprotective agents (CPAs) are found to be required for the cryopreservation media to prevent any freezing damage to cells. A large number of CPAs are available [91], DMSO is the commonest CPAs agent used in cryopreservation of MSCs. However, DMSO toxicity to humans and animals hinders its usage in MSCs freezing for clinical applications. Due to these complications, it is necessary to use an alternate CPA. There are many methods along with the introduction of automated cells washing for the removal of DMSO from the frozen thawed cells [92].

Recently, research and basic knowledge of these cells has fast-tracked, both from fundamental and translational perspectives. There have been important discoveries about the available variety of tissue sources. In addition, novel abilities such as immune-modulation together with improved delivery to the selected optimal tissue site has been discovered. However, the molecular fingerprint of MSCs in these contexts remains imprecise and inadequate. Consequently, without this crucial knowledge the progress is difficult in order to determine with

Stromal Stem Cells: Nature, Biology and Potential Therapeutic Applications

http://dx.doi.org/10.5772/intechopen.77346

17

Overall, the unavoidable propaganda fluctuation that continued for more than 40 years of work on BMSCs did not reduce the novel biological flavor of these cells. Concurrently functioning as stem cells and as cells providing the microenvironment for other stem cells, BMSCs incorporate properties of the "seed" and "soil." As expectations linked to BMSC plasticity are diminishing, these unique properties of BMSCs challenge both biology and medicine in a quite

1 Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Cairo

2 Faculty of Health and Environmental Sciences, School of Interprofessional Health Studies,

[1] Wang S, Qu X, Zhao RC. Clinical applications of mesenchymal stem cells. Journal of

[2] Lindner U, Kramer J, Rohwedel J, Schlenke P. Mesenchymal stem or stromal cells: Toward a better understanding of their biology? Transfusion Medicine and Hemotherapy. Apr

[3] Pittenger MF, Mackay AM, Beck SC, Jaiswal RK, Douglas R, Mosca JD, Moorman MA, Simonetti DW, Craig S, Marshak DR. Multilineage potential of adult human mesenchymal

[4] Friedenstein AJ, Chailakhjan RK, Lalykina KS. The development of fibroblast colonies in monolayer cultures of Guinea-pig bone marrow and spleen cells. Cell and Tissue Kinetics.

3 Faculty of Medical and Health Sciences, School of Pharmacy, University of Auckland,

Hematology & Oncology. Apr 30, 2012;5:19. DOI: 10.1186/1756-8722-5-19

precision the MSCs practical developmental potentials.

Amira Hassouna1,2\*, Marwa M. Abd Elgwad1 and Hoda Fahmy3

Auckland University of Technology (AUT University), New Zealand

stem cells. Science. Apr 2, 1999;284(5411):143-147

\*Address all correspondence to: amira\_hassouna@yahoo.co.uk

remarkable fashion.

Author details

University, Egypt

New Zealand

References

2010;37(2):75-83

Oct 1970;3(4):393-403

The second important factor in cryopreservation of MSCs is the freezing temperature rate. The optimum rate for MSCs preservation is slow freezing at the rate of 1C/min is [93]. For the purpose of maintaining the rate of temperature during cryopreservation, controlled rate freezers (CRFs) are suitable for regulating the temperature. These CRFs can be programmed to determine the exact temperature the sample is experiencing during freezing [94]. Despite of these advantage, these CRFs do not apply a uniform temperature to all vials during large-scale MSCs banking [95], therefore, the development of advanced CRFs is mandatory for large-scale banking. Lately, Praxair Inc. created advanced CRF, providing unidirectional flow of cryogen to each sample. The safe and efficient cryopreservation as well as the regulatory guidelines are important for large-scale MSCs banking. In the U.S.A., Food and Drug Administration (FDA) is responsible for supervising MSCs based cell therapy products, while in Europe it is the European Medicines Agency that is responsible.
