title: Enhanced regeneration of corneal tissue via a bioengineered collagen construct implanted by a nondisruptive surgical technique.
abstract: Severe shortage of donor corneas for transplantation, particularly in developing countries, has prompted the advancement of bioengineered tissue alternatives. Bioengineered corneas that can withstand transplantation while maintaining transparency and compatibility with host cells, and that are additionally amenable to standardized low-cost mass production are sought. In this study, a bioengineered porcine construct (BPC) was developed to function as a biodegradable scaffold to promote corneal stromal regeneration by host cells. Using high-purity medical-grade type I collagen, high 18% collagen content and optimized EDC-NHS cross-linker ratio, BPCs were fabricated into hydrogel corneal implants with over 90% transparency and four-fold increase in strength and stiffness compared with previous versions. Remarkably, optical transparency was achieved despite the absence of collagen fibril organization at the nanoscale. In vitro testing indicated that BPC supported confluent human epithelial and stromal-derived mesenchymal stem cell populations. With a novel femtosecond laser-assisted corneal surgical model in rabbits, cell-free BPCs were implanted in vivo in the corneal stroma of 10 rabbits over an 8-week period. In vivo, transparency of implanted corneas was maintained throughout the postoperative period, while healing occurred rapidly without inflammation and without the use of postoperative steroids. BPC implants had a 100% retention rate at 8 weeks, when host stromal cells began to migrate into implants. Direct histochemical evidence of stromal tissue regeneration was observed by means of migrated host cells producing new collagen from within the implants. This study indicates that a cost-effective BPC extracellular matrix equivalent can incorporate cells passively to initiate regenerative healing of the corneal stroma, and is compatible with human stem or organ-specific cells for future therapeutic applications as a stromal replacement for treating blinding disorders of the cornea.
authors.affiliation: 1 Department of Ophthalmology, Linköping University , Linköping, Sweden .
authors.forename: Marina
authors.initials: M
authors.lastname: Koulikovska
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Rafat
authors.forename: Goran
authors.initials: G
authors.lastname: Petrovski
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Veréb
authors.forename: Saeed
authors.initials: S
authors.lastname: Akhtar
authors.forename: Per
authors.initials: P
authors.lastname: Fagerholm
authors.forename: Neil
authors.initials: N
authors.lastname: Lagali
mesh_terms: D000818:Animals; D001698:Biomedical Engineering / Q000379:methods*; D002465:Cell Movement / Q000187:drug effects; D003094:Collagen / Q000494:pharmacology*; D003315:Cornea / Q000187:drug effects / Q000502:physiology* / Q000601:surgery / Q000648:ultrastructure; D003319:Corneal Stroma / Q000166:cytology; D016039:Corneal Transplantation; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D020007:Implants, Experimental; D007249:Inflammation / Q000473:pathology; D007834:Lasers; D008297:Male; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects; D058628:Myofibroblasts / Q000166:cytology / Q000187:drug effects; D013508:Ophthalmologic Surgical Procedures / Q000379:methods*; D055620:Optical Phenomena; D011509:Proteoglycans / Q000378:metabolism; D011817:Rabbits; D012038:Regeneration / Q000187:drug effects*; D034421:Sus scrofa; D054457:Tissue Scaffolds / Q000737:chemistry*; D014945:Wound Healing / Q000187:drug effects
chemical_list: D011509:Proteoglycans; D003094:Collagen