title: Cryopreserved amniotic membrane as transplant allograft: viability and post-transplant outcome.
abstract: Amniotic membrane (AM) transplantation is increasingly used in ophthalmological and dermatological surgeries to promote re-epithelialization and wound healing. Biologically active cells in the epithelial and stromal layers deliver growth factors and cytokines with anti-inflammatory, anti-bacterial, anti-immunogenic and anti-fibrotic properties. In this work, confocal microscopy was used to show that our cryopreservation protocol for AM yielded viable cells in both the stromal and epithelial layers with favorable post-transplant outcome. AM was obtained from Caesarean-section placenta, processed into allograft pieces of different sizes (3 cm × 3 cm, 5 cm × 5 cm, and 10 cm × 10 cm) and cryopreserved in 10 % dimethyl sulfoxide using non-linear controlled rate freezing. Post-thaw cell viability in the entire piece of AM and in the stromal and epithelial cell layers was assessed using a dual fluorescent nuclear dye and compared to hypothermically stored AM, while surveys from surgical end-users provided information on post-transplant patient outcomes. There was no significant statistical difference in the cell viability in the entire piece, epithelial and stromal layers regardless of the size of allograft piece (p = 0.092, 0.188 and 0.581, respectively), and in the entire piece and stromal layer of hypothermically stored versus cryopreserved AM (p = 0.054 and 0.646, respectively). Surgical end-user feedback (n = 49) indicated that 16.3 % of AM allografts were excellent and 61.2 % were satisfactory. These results support the expanded clinical use of different sizes of cryopreserved AM allografts and address the issue of orientation of the AM during transplant for the treatment of dermatological defects and ocular surface disorders.
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada.
authors.forename: Natasha M J
authors.initials: NM
authors.lastname: Perepelkin
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Hayward
authors.affiliation: Comprehensive Tissue Centre, Alberta Health Services, Edmonton, AB, Canada.
authors.forename: Tumelo
authors.initials: T
authors.lastname: Mokoena
authors.affiliation: Comprehensive Tissue Centre, Alberta Health Services, Edmonton, AB, Canada.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bentley
authors.affiliation: Comprehensive Tissue Centre, Alberta Health Services, Edmonton, AB, Canada.|Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada.|Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada.
authors.forename: Lisa U
authors.initials: LU
authors.lastname: Ross-Rodriguez
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada.|Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada.
authors.forename: Leah
authors.initials: L
authors.lastname: Marquez-Curtis
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada.
authors.forename: Locksley E
authors.initials: LE
authors.lastname: McGann
authors.affiliation: Comprehensive Tissue Centre, Alberta Health Services, Edmonton, AB, Canada.|Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada.
authors.forename: Jelena L
authors.initials: JL
authors.lastname: Holovati
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada. janet.elliott@ualberta.ca.|Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada. janet.elliott@ualberta.ca.
authors.forename: Janet A W
authors.initials: JA
authors.lastname: Elliott
mesh_terms: D064591:Allografts / Q000637:transplantation*; D000650:Amnion / Q000637:transplantation*; D002470:Cell Survival; D015925:Cryopreservation / Q000379:methods*; D004847:Epithelial Cells / Q000166:cytology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D018613:Microscopy, Confocal; D010920:Placenta / Q000502:physiology; D011247:Pregnancy; D013194:Staining and Labeling; D017154:Stromal Cells / Q000166:cytology; D014022:Tissue Survival
keywords: Amniotic membrane; Cryobiology; Cryopreservation; Dermal surgery; Epithelium; Ocular surgery; Stroma; Tissue transplantation