Genome-wide association study for osteoarthritis

Robert Kirsner and colleagues (Sept 15, p 977) describe a spray formulation of allogeneic neonatal keratinocytes and fi broblasts for the treatment of chronic venous leg ulcers. Such therapies are novel and of major interest. However, although this technique certainly has potential, we have some concerns about the interpretation of the results of Kirsner and colleagues’ study. First, it is not clear whether Kirsner and co-workers tested the viability of the fibroblasts and keratinocytes. Viable cells are crucial in the treatment of ulcers. Second, why are there no representative fi gures to show that wound healing was greater with 0·5×106 cells/mL every 14 days than with vehicle alone? Third, the follow-up (12 weeks) was too short to show the eff ect of spray-applied cell therapy with human allogeneic fi broblasts and keratinocytes on longterm outcomes. Were there any such follow-up fi ndings with regard to this technology? Finally, this spray-applied cell therapy contains compound solutions, including cells and matrix. It would be interesting to know which part is responsible for the clinical eff ects, and whether the mechanisms of action are direct (diff erentiation into myofi broblast or vascular endothelial cells), indirect (cell–cell contact or paracrine eff ects), or both.