Corneal xenotransplantation in ophthalmology: challenges and prospects

Introduction. This paper evaluates the key structural characteristics of turkey cornea and critically analyzes both the obtained results and existing literature to assess the feasibility of using this xenogeneic material for keratoplasty. Currently, more than 12 million patients worldwide are awaiting keratoplasty. The prolonged waiting times is largely driven by severe shortage of cadaveric human corneas required for the procedure. Recent studies have generated growing optimism regarding the potential of xenogeneic keratoplasty; however, the number of animal donors studied to date remains quite limited. In light of this gap, the objective of this study was formulated.

Objective: to assess the main structural characteristics of turkey (Meleagris gallopavo) cornea and to evaluate its potential use as a xenogeneic material for selective keratoplasty.

Materials and methods. Corneoscleral buttons (n = 24) were isolated from enucleated turkey eyeballs. In the first stage, the corneal microstructure was examined using scanning electron microscopy and confocal microscopy. In the second stage, the feasibility of cutting out a corneal xenograft suitable for deep anterior lamellar keratoplasty was evaluated. In the third stage, the potential for preservation of the obtained xenografts using xenogeneic turkey corneal material was assessed.

Results. The turkey cornea was shown to possess all the principal layers characteristic of the human cornea. Its mean thickness was 508 ± 33.5 μm, and the presence of Bowman’s membrane was confirmed. Preservation of the turkey cornea for up to five days was feasible while maintaining a high endothelial cell density. In addition, the preparation of a xenograft suitable for deep Anterior lamellar keratoplasty from turkey corneal tissue was successfully demonstrated.

Conclusion. Analysis using confocal microscopy and scanning electron microscopy, together with assessment of xenograft integrity following hypothermic preservation, indicates that turkey cornea represents a promising xenogeneic material for selective keratoplasty. Further studies are warranted to assess its potential application in reconstructive corneal surgery.

1. Ackland P, Resnikoff S, Bourne R. World blindness and visual impairment: despite many successes, the problem is growing. Community Eye Health. 2017; 30 (100): 71–73.

2. Holland G, Pandit A, Sánchez-Abella L, Haiek A, Loinaz I, Dupin D et al. Artificial Cornea: Past, Current, and Future Directions. Front Med (Lausanne). 2021 Nov 12; 8: 770780. doi: 10.3389/fmed.2021.770780.

3. Gain P, Jullienne R, He Z, Aldossary M, Acquart S, Cognasse F, Thuret G. Global Survey of Corneal Transplantation and Eye Banking. JAMA Ophthalmol. 2016 Feb; 134 (2): 167–173. doi: 10.1001/jamaophthalmol.2015.4776.

4. Yoon CH, Choi HJ, Kim MK. Corneal xenotransplantation: Where are we standing? Prog Retin Eye Res. 2021 Jan; 80: 100876. doi: 10.1016/j.preteyeres.2020.100876.

5. Nascimento H, Martins TMM, Moreira R, Barbieri G, Pires P, Carvalho LN et al. Current Scenario and Future Perspectives of Porcine Corneal Xenotransplantation. Cornea. 2025 Mar 1; 44 (3): 387–404. doi: 10.1097/ICO.0000000000003723.

6. Kim MK, Hara H. Current status of corneal xenotransplantation. Int J Surg. 2015 Nov; 23 (Pt B): 255–260. doi: 10.1016/j.ijsu.2015.07.685.

7. Maghsoudlou P, Sood G, Gurnani B, Akhondi H. Cornea Transplantation. 2024 Feb 24. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan. Available from: https://pubmed.ncbi.nlm.nih.gov/30969512/.

8. Crawford AZ, Patel DV, McGhee CNj. A brief history of corneal transplantation: From ancient to modern. Oman J Ophthalmol. 2013 Sep; 6 (Suppl 1): S12–S17. doi: 10.4103/0974-620X.122289.

9. Hara H, Cooper DK. Xenotransplantation – the future of corneal transplantation? Cornea. 2011 Apr; 30 (4): 371–378. doi: 10.1097/ICO.0b013e3181f237ef.

10. Song YW, Pan ZQ. Reducing porcine corneal graft rejection, with an emphasis on porcine endogenous retrovirus transmission safety: a review. Int J Ophthalmol. 2019 Feb 18; 12 (2): 324–332. doi: 10.18240/ijo.2019.02.21.

11. Islam R, Islam MM, Nilsson PH, Mohlin C, Hagen KT, Paschalis EI et al. Combined blockade of complement C5 and TLR co-receptor CD14 synergistically inhibits pig-to-human corneal xenograft induced innate inflammatory responses. Acta Biomater. 2021 Jun; 127: 169–179. doi: 10.1016/j.actbio.2021.03.047.

12. Shi Y, Bikkuzin T, Song Z, Jin X, Jin H, Li X, Zhang H. Comprehensive evaluation of decellularized porcine cor- neal after clinical transplantation. Xenotransplantation. 2017 Nov; 24 (6): e12338. doi: 10.1111/xen.12338.

13. Zheng J, Huang X, Zhang Y, Wang Y, Qin Q, Lin L et al. Short-term results of acellular porcine corneal stroma keratoplasty for herpes simplex keratitis. Xenotransplantation. 2019 Jul; 26 (4): e12509. doi: 10.1111/xen.12509.

14. Zheng Q, Zhang Y, Ren Y, Zhao Z, Hua S, Li J et al. Deep anterior lamellar keratoplasty with cross-linked acellular porcine corneal stroma to manage fungal keratitis. Xenotransplantation. 2021 Mar; 28 (2): e12655. doi: 10.1111/xen.12655.

15. Liu XN, Zhu XP, Wu J, Wu ZJ, Yin Y, Xiao XH et al. Acellular ostrich corneal stroma used as scaffold for construction of tissue-engineered cornea. Int J Ophthalmol. 2016 Mar 18; 9 (3): 325–331. doi: 10.18240/ijo.2016.03.01.

16. Nesterov AP. Experimental studies on transplantation of heterogeneous cornea: Abstract of Cand. Sci. (Medicine) dissertation. Kuibyshev, 1956; 20.