Pavia symposium on embryos and stem cells.

Stem cells occur in very small numbers in adult tissues, in higher numbers in the fetus and its annexes and they can be derived from whole embryos or parts thereof. For a couple of years, stem cells can also be derived straight from somatic cells by retrovirus-mediated transfer of selected genes in culture. Stem cells have varying capacities for self-renewal and differentiation according to their origin, up to the point that they can be propagated in vitro for years and give rise to a wide range of cell types. This makes them suitable means for cell and tissue-replacement therapies. Gaining access to stem cells involves manipulation of living organisms i.e. human beings or animal models. The extent of manipulation ranges from the mere biopsy and culture of body cells in vitro, to their genetic manipulation and back-grafting in vivo.This raises bioethical issues as to whether we should manipulate animal and in particular human life. Many scientific meetings have been organized to present research findings on stem cells and on their potency, differentiation and therapeutic applications for treating disease. In many of these meetings, the ‘mother’ of all stem cells the embryo has often been ignored, because embryonic stem cells do not exist as such in the embryo and because the manipulation of the embryo brings up ethical concerns. To make up for this omission, the theme of our meeting was ‘Pluripotency and differentiation in embryos and stem cells’. With a strong sense of purpose and commitment, we managed to hold a two-day symposium concerned with three major topics: 1) natural and induced pluripotency; 2) mechanisms of cell fate control; 3) adult and cancer stem cells. The meeting took place on January 17-18 2008 in the beautiful, frescoed halls of Collegio Ghislieri and Borromeo, two foremost colleges in the Pavia campus. A small but prominent group of scientists took part in the meeting – James Adjaye (Germany), Anne Grete Byskov (Denmark), Jose Cibelli (USA), Ruggero De Maria (Italy), Stephen Minger (UK), Maurilio Sampaolesi (Belgium), Hans Schöler (Germany), Giuseppe Testa (Italy), Catherine Verfaillie (Belgium) and Magdalena Zernicka-Goetz (UK). Here, we present the organizers’ perspective on the meeting. It goes without saying that we may not have rendered the contents the same way as the speakers did, but we do hope that the overall meaning was preserved. The speakers have been invited to contribute to a comprehensive account of the meeting, and we hope this report makes a good start.