**Part 2**

**Stem Cells and Cryopreservation in Regenerative Medicine** 

136 Current Frontiers in Cryobiology

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Gao,D. Y. (2011) A Dilution-filtration Method for Removing Cryoprotective Agents.

**5** 

*(CIBERNED)* 

*1,2,3Spain 4Sweden* 

*Huddinge, Stockholm,* 

**Cryopreservation of Human Pluripotent Stem** 

*1Departament de Biologia Cellular, Immunologia i Neurociències, Programa de Terapia* 

*Intervention and Technology, Karolinska Institutet, K57, Karolinska University Hospital,* 

The first derivation of human embryonic stem cells (hESCs) (Thomson et al., 1998) and the more recently development of human induced pluripotent stem cells (iPSCs) (Park et al., 2008; Takahashi et al., 2007; Takahashi & Yamanaka, 2006; Wernig et al., 2007; Yu et al., 2007) have marked the beginning of a new era in biomedical research. These two types of human pluripotent stem cells (hPSCs) are characterized by an unlimited capacity to selfrenew while retaining their potential to differentiate into almost all cell types of the body (Odorico et al., 2001; Reubinoff et al., 2000; Silva & Smith, 2008). These remarkable properties turn hPSCs into one of the most interesting cell types for toxicology and drug discovery, tissue engineering and regenerative medicine (Battey, 2007; Mountford, 2008). In fact, work with hPSCs has already provided new and exciting developments that may eventually lead to the creation of novel cell-based therapies for the treatment of a wide range of human diseases including Parkinson's and other neurodegenerative diseases, diabetes, cardiac and vascular diseases (Kiskinis & Eggan, 2010; Ronaghi et al., 2010). However, a major challenge for the widespread application of hPSCs is the development of

To date, two techniques are mainly applied for the cryopreservation of hPSCs: conventional slow freezing and vitrification. The conventional slow-freezing and rapid-thawing procedure using dimethylsulfoxide (DMSO) as a cryoprotectant is the most commonly used method (Grout et al., 1990; Meryman, 2007). While this established technique is effective for somatic cell lines and even murine embryonic stem cells (mESCs), hematopoietic and mesenchymal human stem cells, this is not the case for hPSCs, due to low recovery rates and high levels of differentiation (Berz et al., 2007; Reubinoff et al., 2001; Richards et al., 2004; Thirumala et al., 2010). In contrast, vitrification of hPSCs by the "open pulled straw" method

**1. Introduction** 

efficient protocols for cryopreservation.

*2Institut de Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona 3Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas* 

**Cells: Are We Going in the Right Direction?** 

Raquel Martín-Ibáñez1,2,3, Outi Hovatta4 and Josep M. Canals1,2,3

*Cellular, Facultat de Medicina, Universitat de Barcelona, Barcelona* 

*4Division of Obstetrics and Gynecology, Department of Clinical Science,* 

*4Sweden* 
