Adipose tissue seems to be a rich and safe source of mesenchymal stem cells (MSCs). The present study was aimed to investigate the biological and morphological characteristics of human adipose tissue-derived stem cells (ATSCs). Light and transmission electron microscopy were used. Course of proliferation was analyzed by growth curve. Expression of surface antigens was assessed by flow cytometry. Chondrogenic potential was assessed by immunohistochemistry. Obtained results showed morphology typical of fibroblastoid cells. TEM analysis proved ultrastructural morphology similar to MSCs from other sources. ATSCs reflected their proteosynthetic and metabolic activity. Each cell had irregular shape of nucleus with noticeable nucleoli. Abundant cisterns of rough endoplasmic reticulum were present in their cytoplasm. Karyotype mapping showed normal count of human chromosomes (46,XX). The growth curve revealed high capability for proliferation and population doubling time was 27.36 hours. ATSCs were positive for CD13, CD29, CD44, CD73, CD90, CD105 and CD106, but did not express CD14, CD34, CD45 and HLA-DR. It was also proved that ATSCs underwent chondrogenic differentiation in vitro. On the basis of obtained results it should be emphasized that ATSCs are typical MSCs and after further investigations they may be used in tissue engineering and regenerative medicine.

Somatic stem cells possess unique properties of self-renewal and plasticity which make them promising candidates for use in tissue engineering and regenerative medicine, in addition to serving as efficient delivery vehicles in site-specific therapy. In the case of therapeutic application, it is essential to isolate and culture stem cells in vitro, to obtain them in sufficient quantities. Although long-term cultivation provides an adequate number of cells, it has been shown that this approach is associated with increased risk of transformation of cultured cells, which presents a significant biological hazard. This article reviews information about biological features and cellular events which occur during long-term cultivation of somatic stem cells, with respect to their safe utilization in potential clinical practice.