The University of Edinburgh/University of California at Los Angeles
Title of Abstract
Mesenchymal stem cells are favourite regenerative cells in multiple protocols of cell therapy and tissue engineering. MSCs have been tested in about 800 clinical trials; this interest is justified by the diverse and robust potentials deployed by these cells to achieve tissue (re)generation and repair: MSCs can be tissue progenitors but also, via cell contact and secretion of trophic factors, stimulate angiogenesis, regulate immune/inflammatory reactions and support lineage committed stem cells. Moreover, mesenchymal stem cells are easy to derive and expand from virtually any vascularized organ, leaving a choice of convenient, abundant and dispensable sources such as adult abdominal fat and foetal appendages at birth. On the other hand, indirect selection by adherence and proliferation in culture has obscured the biologic characteristics of innate mesenchymal stem cells. MSCs being by definition long-term cultured cells, their native embryonic origin, identity, lineage affiliation, tissue distribution, frequency and – importantly – natural role in tissue homeostasis and repair has remained unknown decades after their initial discovery. In the past ten years, the very identity of native mesenchymal stem cells has been gradually uncovered, revealing a perivascular origin for these elusive regenerative cells. Natural MSCs are pericytes, encircling capillaries and micro-vessels, and adventitial cells surrounding large arteries and veins. Prospective identification of innate MSCs now opens the possibility of using highly purified, uncultured and precisely characterized mesenchymal stem cells for cell therapies. We will discuss the cellular and molecular characterization of human MSCs, the natural role of subsets of these cells in the fibrotic degeneration or repair of skeletal and cardiac muscles, and the use thereof in diverse cell therapy protocols.
Prospective identification and purification and functional characterization of multi-lineage stem cells present in human adult organs and tissues.