Two MSCs

Conclusion

Mesenchymal stem cells can be isolated from bone marrow by standardized techniques and expanded in culture through many generations, while retaining their capacity to differentiate along set pathways when exposed to appropriate conditions. This property opens up therapeutic opportunities for the treatment of lesions in mesenchymal tissues, and protocols have been devised for the treatment of defects in articular cartilage 71), bone 72), tendon 73), and meniscus 74) and for bone marrow stromal recovery 75) and osteogenesis imperfecta 76).

In this context, we prefer to use the word ‘stroma’ rather than ‘mesenchymal stem cells’ for accuracy and to avoid confusion. In the field of hematopoiesis, marrow stroma were originally treated as ‘second class citizens’ 77), and represented a niche field. Today, marrow stroma are a ‘major player’ in regenerative medicine and stem cell biology and are no longer viewed as a peripheral field of research. In addition, there is also a rapidly growing body of research into the biology and potential use of true ‘mesenchymal stem cells’ derived from other human tissues, which are showing significant promise for future therapy, reparation or regeneration of human tissues and organs.

Clearly, this field is in its relative infancy, our understanding is at present limited but the potential benefits are great. We should perhaps, therefore, remember that the unexpected and unrivalled potential of MSCs to differentiate into a wide variety of cells represents a gift not a privilege and, with respect to the two MSCs, we should recognise and welcome their role in medicine with the words “with great power comes great responsibility”.