Embryonic stem cells – current knowledge and futire prospects

Abstract

Embryonic stem cells bona fide encompass cells of the inner cell mass, explanted from blastocysts, that exist exclusively in in vitro culture systems. To qualify for a stem cell, one has to be capable of self-renewal, multilineage differentiation and functional repopulation of a target tissue. Besides essential aspects of stem cell biology, in this review, we discuss categories according to the differentiation potential or plasticity of stem cells which is closely intertwined with their developmental rank in mammals ranging from totipotent zygote to monopotent stem cells. Aspects of embryonic stem cells, their isolation, signalling pathways governing their self-renewal and pluripotency, markers, genetic modification and differentiation are reviewed. Finally, we outline some hurdles, challenges and outlooks in the field of stem cell research and its promises for regenerative and replacement therapies.