The body comprises different types of progenitor cells (stem cells) capable of giving rise to cells with more restricted developmental potential. Stem cells (SCs) occur as unspecialized cells, lacking tissue specific characteristics, but maintaining undifferentiated phenotype until they are exposed to appropriate signals. SCs have capacity for extensive self-renewal, and apparently maintain themselves throughout the entire life of an organism. Under the influence of specific signals, SCs can differentiate into specialized cells of different lineages. SCs include embryonic stem cells (ESCs), isolated from the inner cell mass of the blastocyst [1],  and mesenchymal stromal cells (MSCs), isolated from fetal and adult tissues.

Adult MSCs are multipotent cells isolated from different tissues for example, adipose tissue [2] and bone marrow, among others. These cells can also be isolated from extra-embryonic tissues, including placenta, amniotic fluid, and umbilical cord [3].

The International Society for Cellular Therapy (ISCT) stated that MSCs are characterized by: plastic adherence to tissue culture flasks; 95% of the MSC population must express the surface markers CD105, CD73 and CD90 and lack expression of CD45, CD34, CD14 or CD11b, CD79a or CD19 and HLA class II; Finally, the cells must differentiate in vitro into osteoblasts, adipocytes and chondrocytes under standard differentiating conditions [4]. Another important characteristic is the colony forming unity fibroblasts (CFU-Fs) assays to assess the clonogenicity of MSCs i.e., the ability of a cell to grow in a density-insensitive fashion [5].

Autologous approaches to use MSCs, namely from bone marrow, have difficulties regarding the limited availability of cells from the patient. Cell expansion protocols are based on the use of media supplemented with fetal bovine serum (FBS) as a source of nutrientes and growth factors. The animal serum is not completely safe, once there is a possibility of contamination by animal viroses, prions or others contaminants and it is described that FBS used systematically in MSCs subcultivation induces more humoral immune response [6]. Platelet lysate (PL) has enormous possibilities in cell therapy, namely because of the high concentration of growth factors that promotes higher cell expansion, such as tissue regeneration [7].