Human Serum Promotes Osteogenic Differentiation of Human Dental Pulp Stem Cells <em>In Vitro</em> and <em>In Vivo</em>

<div><p>Human dental pulp is a promising alternative source of stem cells for cell-based tissue engineering in regenerative medicine, for the easily recruitment with low invasivity for the patient and for the self-renewal and differentiation potential of cells. So far, <em>in vitro</em> culture of mesenchymal stem cells is usually based on supplementing culture and differentiation media with foetal calf serum (FCS). FCS is known to contain a great quantity of growth factors, and thus to promote cell attachment on plastic surface as well as expansion and differentiation. Nevertheless, FCS as an animal origin supplement may represent a potential means for disease transmission besides leading to a xenogenic immune response. Therefore, a significant interest is focused on investigating alternative supplements, in order to obtain a sufficient cell number for clinical application, avoiding the inconvenients of FCS use. In our study we have demonstrated that human serum (HS) is a suitable alternative to FCS, indeed its addition to culture medium induces a high hDPSCs proliferation rate and improves the <em>in vitro</em> osteogenic differentiation. Furthermore, hDPSCs-collagen constructs, pre-differentiated with HS-medium <em>in vitro</em> for 10 days, when implanted in immunocompromised rats, are able to restore critical size parietal bone defects. Therefore these data indicate that HS is a valid substitute for FCS to culture and differentiate <em>in vitro</em> hDPSCs in order to obtain a successful bone regeneration <em>in vivo</em>.</p>