title: Response of human limbal epithelial cells to wounding on 3D RAFT tissue equivalents: effect of airlifting and human limbal fibroblasts.
abstract: Limbal epithelial stem cell deficiency can cause blindness but may be treated by human limbal epithelial cell (hLE) transplantation, normally on human amniotic membrane. Clinical outcomes using amnion can be unreliable and so we have developed an alternative tissue equivalent (TE), RAFT (Real Architecture for 3D Tissue), which supports hLE expansion, and stratification when airlifted. Human limbal fibroblasts (hLF) may be incorporated into RAFT TEs, where they support overlying hLE and improve phenotype. However, the impact of neither airlifting nor hLF on hLE function has been investigated. hLE on RAFT TEs (±hLF and airlifting) were wounded using heptanol and re-epithelialisation (fluorescein diacetate staining), and percentage putative stem cell marker p63α and proliferative marker Ki67 expression (wholemount immunohistochemistry), measured. Airlifted, hLF- RAFT TEs were unable to close the wound and p63α expression was 7 ± 0.2% after wounding. Conversely, non-airlifted, hLF- RAFT TEs closed the wound within 9 days and p63α expression was higher at 22 ± 5% (p < 0.01). hLE on both hLF- and hLF+ RAFT TEs (non-airlifted) closed the wound and p63α expression was 26 ± 8% and 36 ± 3% respectively (ns). Ki67 expression by hLE increased from 1.3 ± 0.5% before wounding to 7.89 ± 2.53% post-wounding for hLF- RAFT TEs (p < 0.01), and 0.8 ± 0.08% to 17.68 ± 10.88% for hLF+ RAFT TEs (p < 0.05), suggesting that re-epithelialisation was a result of proliferation. These data suggest that neither airlifting nor hLF are necessarily required to maintain a functional epithelium on RAFT TEs, thus simplifying and shortening the production process. This is important when working towards clinical application of regenerative medicine products.
authors.affiliation: Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK. Electronic address: i.massie@ucl.ac.uk.
authors.forename: Isobel
authors.initials: I
authors.lastname: Massie
authors.affiliation: Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK. Electronic address: h.levis@ucl.ac.uk.
authors.forename: Hannah J
authors.initials: HJ
authors.lastname: Levis
authors.affiliation: Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK. Electronic address: j.daniels@ucl.ac.uk.
authors.forename: Julie T
authors.initials: JT
authors.lastname: Daniels
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002452:Cell Count; D018929:Cell Culture Techniques; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism; D019573:Epithelium, Corneal / Q000166:cytology* / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology*; D019850:Heptanol / Q000633:toxicity; D006801:Humans; D016850:Limbus Corneae / Q000166:cytology* / Q000378:metabolism; D018613:Microscopy, Confocal; D009924:Organ Culture Techniques; D062326:Re-Epithelialization; D013552:Swine; D014019:Tissue Donors; D023822:Tissue Engineering; D054457:Tissue Scaffolds; D014157:Transcription Factors / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D014945:Wound Healing / Q000502:physiology*
chemical_list: D015415:Biomarkers; C115051:TP63 protein, human; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D019850:Heptanol
keywords: 3D wound model; cell therapy; cornea; limbal epithelial stem cell; limbal fibroblast; limbus; regenerative medicine; tissue-engineering