Adult stem cell lines in regenerative medicine and reconstructive surgery.

In recent years, there has been a tremendous increase in the understanding of stem cell biology. The potential clinical applications lead to an extended interest in the use of stem cells in many medical disciplines. Multipotent adult stem cells seem to be almost comparable to embryonic stem cells with respect to their ability to differentiate into various tissues in vitro and in vivo, a function that has been termed "stem cell plasticity". In vivo experiments in rodents have shown that adult stem cells participate in tissue- and organ regeneration in almost all lesions. Although stem cell populations isolated from the bone marrow are usually a heterogeneous mix of different subpopulations, cloned adult stem cell lines from any source also show a broad spectrum of differentiation potential, e.g., osteogenesis, myogenesis, neurogenesis, or angiogenesis in wound healing. Angiogenesis in particular is a subject in tissue regeneration with tremendous implication in reconstructive surgery. This comprehensive plasticity makes it possible to use stem cell lines for biomedical research, tissue engineering, regenerative surgery, and organ repair. Adult stem cell lines are molecularly well defined with respect to transcription factors, active signal transduction pathways, and expression of receptors/ligand pairs. We performed experiments with adult stem cell lines, which are not subject to stem cell heterogeneity. Results obtained with stem cell lines can reliably be ascribed to the stem cell population under scrutiny. Adult stem cell lines can be obtained with the necessary quality and quantity also to study many effects of human stem cells in vitro and in vivo. In this paper, we summarize some of the tremendous therapeutic implications of adult stem cell lines in surgery and surgical research.