[1] Univ Cambridge, Sch Clin Med, Cambridge, England
[2] Wythenshawe Hosp, Dept Plast & Reconstruct Surg, Manchester, Lancs, England
[3] Univ Cambridge, Emmanuel Coll, Cambridge, England
[4] Cambridge Stem Cell Inst, Wellcome Trust Med Res Council, Anne McLaren Lab Regenerat Med, Cambridge, England