ABSTRACT
There is a growing clinical interest in regenerative medicine and stem cell therapies in the use of biomaterials made from human autologous (or allogeneic) blood because these products do not induce tissue reaction, are biodegradable and exhibit valuable physiological functions. The fi rst generation of blood-derived biomaterials called fi brin sealant, or fi brin glue, obtained by mixing a fi brinogen-rich fraction with thrombin were developed in the early 1900’s and became available for routine clinical use in the 1980’s in Europe and, later, in the USA (Radosevich et al. 1997, Jackson et al. 1996, Martinowitz and Saltz 1996, Spotnitz 2001, Mintz et al. 2001, Spotnitz and Prabhu 2005, Burnouf et al. 2009). Those glue-like sealants exhibit hemostatic and sealing properties. Both industrial and single-donor
1Department of Dentistry, National Yang-Ming University, Taipei, Taiwan. Email: henrycysu@gmail.com 2College of Oral Medicine, Taipei Medical University, Taipei, Taiwan & Human Protein Process Sciences (HPPS), Lille, France. *Corresponding author
fi brin sealants are currently available for use in many fi elds such as cardiac, plastic, oral, orthopedic, aesthetic, and implant surgeries (Radosevich et al. 1997, Burnouf et al. 2009). A second group of blood-derived biomaterials, called platelet gels (PLT gels), encompasses different types of products, depending upon their mode of preparation (Jackson et al. 1996, Burnouf et al. 2009, Everts et al. 2006a, Borzini and Mazzuco 2005, Marx 2001, Marx 2004). These are single-donor (usually autologous, more rarely allogenic) products obtained by combining platelet-rich plasma (PRP) with thrombin. The mixing of both fractions results in (a) the conversion of fi brinogen into fi brin, (b) the activation of platelets and (c) the release of a myriad of growth factors (GF) stored in the platelet α-granules (Blair and Flaumenhaft 2009). Upon activation by exogenous or endogenous agonists, platelets release a myriad of functional molecules which play a key role in tissue repair and regeneration by stimulation and differentiation of local stem cells (Marx et al. 1998). Among these are the numerous growth factors entrapped within alpha-granules: platelet-derived growth factors (PDGF) -AA, -BB, or -AB, transforming growth factor-β (TGF-β1 and -2), vascular endothelium growth factor (VEGF), epidermal growth factor (EGF), fi broblast growth factor-1 (FGF-1), brain-derived neurotrophic factor (BDNF), etc. Human platelet growth factors are now explored and proven to be unique non-toxic biocompatible tools for tissue engineering, stem cell expansion in vitro and cell therapy. GF-rich biomaterials, combined, or not, with fi brin glue, can be used as matrix for cell cultures (chondrocytes, keratinocytes, etc.) prior to implant. They can also be used as cell carriers for in vivo delivery to damaged tissues, e.g., for the healing of soft and hard tissues. Understandably, human platelet lysates rich in growth factors and other bioactive molecules are increasingly used successfully as a medium supplement to replace fetal bovine serum for the expansion of mesenchymal stem cells from various origins, opening new perspectives for the clinical development of stem cellbased cell therapy (Kazemnejad et al. 2008, Doucet et al. 2005, Vogel et al. 2006, Schallmoser and Strunk 2009, Kocaoemer et al. 2007, Shih et al. 2011). In this chapter, we present the four main categories of biomaterials made from human blood and their specifi city in biochemical and physiological properties as well as their clinical applications in particular in the fi eld of regenerative medicine and cell therapy. The main characteristics of these four biomaterials are summarized in Table 3.1.
