Harnessing the potential of adult cardiac stem cells: lessons from haematopoiesis, the embryo and the niche.

Across biomedicine, there is a major drive to develop stem cell (SC) treatments for debilitating diseases. Most effective treatments restore an embryonic phenotype to adult SCs. This has led to two emerging paradigms in SC biology: the application of developmental biology studies and the manipulation of the SC niche. Developmental studies can reveal how SCs are orchestrated to build organs, the understanding of which is important in order to instigate tissue repair in the adult. SC niche studies can reveal cues that maintain SC 'stemness' and how SCs may be released from the constraints of the niche to differentiate and repopulate a 'failing' organ. The haematopoietic system provides an exemplar whereby characterisation of the blood lineages during development and the bone marrow niche has resulted in therapeutics now routinely used in the clinic. Ischaemic heart disease is a major cause of morbidity and mortality in humans and the question remains as to whether these principles can be applied to the heart, in order to exploit the potential of adult SCs for use in cardiovascular repair and regeneration.