He noted, that since the Friedenstein’s pioneering work, nobody was able to address the problem of MSC identity. In fact, such characteristics of MSC and fibroblasts as morphology, phenotype, gene expression profile, immunologic properties, tissue repair mechanisms are remarkably similar or even indistinguishable.
… there are no distinct differences in culture-derivation methodology, morphology, cell-surface marker expression pattern, differentiation potential and gene expression signature that consistently and unequivocally distinguish ex vivo culture-expanded ‘MSC’ from ‘fibroblasts’.
Some examples of “mistaken and confused identity”, that he gave in the article:
Surface markers and tri-lineage differentiation:
Multilineage differentiation potential of human dermal skin-derived fibroblasts
MSC versus pericytes versus fibroblasts
Dermal fibroblasts versus fat-derived MSC
Interestingly, he pointed out some clinical questions, such as:
If MSC are indeed fibroblasts, and fibroblasts are responsible for fibrosis, should we be concerned about the potential for fibrogenic effects of MSC given to treat inflammatory conditions? The answer is probably no, because so far there is no evidence to suggest that MSC engrafts long-term after infusion, despite clinical benefits observed (40). Nevertheless, some patients receiving MSC in a clinical trial for treatment of refractory chronic graft-versus-host disease (GvHD) developed bronchiolitis obliterans; although causality between receiving MSC and the development of this fibrotic lung disease is not certain.
Forty years after the first description of bone marrow fibroblasts by Friedenstein, and despite the introduction of the more popular term ‘MSC’, little has changed about the way we derive and culture these cells. There is no accepted single cell-surface marker for their isolation and, because they are ex vivo culture-expanded from a small population of cells, there is still no sure way to trace them back to their in vivo counterparts. Our efforts to name these fibroblast-looking cells in culture can be likened to the old Indian tale of six men in a dark room asked to describe an elephant.
Very interesting opinion piece. Highly recommended!
Also read: Mesenchymal stem cells: the fibroblasts’ new clothes?