Methodological aspects of attempts to trans-differentiate adult stem cells into embryonic-like cells in vitro.

Abstract

AIMS: The aim of this research was to set up an in vitro system to trans-differentiate haematopoietic stem cells (HSCs) into embryo-like stem cells in order to de-differentiate them. In this more naive state they should be cultivated more easily in order to augment them for consecutive differentiation and autologous transplantation for use in clinical practice. METHODS: Using the principle of the methodology of blastocyst injection, HSCs were co-cultivated with mouse embryonic stem cells (mES) with and without cell to cell contact. After co-cultivation HSCs were analyzed by flow-cytometry using haematopoietic markers (CD34, CD45, CD133) and embryonic stem cell markers (SSEA-4, Tra-1-60, Tra-1-81). RESULTS: No ES cell markers were detected on the former HSCs. A decrease in HSC marker intensity was the only finding. This implies that no de-differentiation took place. CONCLUSIONS: We hypothesize that the unnatural situation of a mixture of two cell types originating in different species may have led to this outcome. To achieve our goal of in vitro de-differentiation we need to use a purely human culture system without animal additives.