The Resistance of Riboflavin/UV-A Corneal Cross-Linking to Enzymatic Digestion Is Oxygen-Independent.

Autor:	Hafezi NL; ELZA Institute, Dietikon, Switzerland.; Department of Ophthalmology, Antwerp University Hospital, Edegem, Antwerp, Belgium ; and., Aydemir ME; ELZA Institute, Dietikon, Switzerland., Lu NJ; ELZA Institute, Dietikon, Switzerland.; Department of Ophthalmology, Antwerp University Hospital, Edegem, Antwerp, Belgium ; and., Torres-Netto EA; ELZA Institute, Dietikon, Switzerland.; Laboratory for Ocular Cell Biology, Center for Applied Biotechnology and Molecular Medicine, University of Zurich, Zurich, Switzerland., Hillen M; ELZA Institute, Dietikon, Switzerland., Koppen C; Department of Ophthalmology, Antwerp University Hospital, Edegem, Antwerp, Belgium ; and.
Jazyk:	angličtina
Zdroj:	Cornea [Cornea] 2024 Jul 01; Vol. 43 (7), pp. 895-898. Date of Electronic Publication: 2024 Feb 23.
DOI:	10.1097/ICO.0000000000003502
Abstrakt:	Purpose: Corneal cross-linking (CXL) with riboflavin and UV-A induces several effects in the cornea, including biomechanical stiffening, generation of reactive oxygen species, and increased resistance to enzymatic digestion. Whereas the biomechanical stiffening effect is oxygen-dependent, little is known about the effect of oxygen on the resistance to enzymatic digestion. Here, we examined CXL-induced enzymatic resistance in the absence of oxygen. Methods: Ex vivo porcine corneas (n = 160) were assigned to 5 groups. Group 1 was the control group (abrasion and riboflavin application). Groups 2 and 3 received accelerated 10 and 15 J/cm 2 high-fluence CXL protocols in the presence of oxygen (9'15″ @ 18 mW/cm 2 and 8'20″ @ 30 mW/cm 2 , respectively), whereas groups 4 and 5 received accelerated 10 and 15 J/cm 2 high-fluence CXL protocols in the absence of oxygen (oxygen content less than 0.1%). After CXL, corneas were digested in 0.3% collagenase A solution. Mean time until complete dissolution was determined. Results: The mean times to digestion in groups 1 through 5 were 22.31 ± 1.97 hours, 30.78 ± 1.83 hours, 32.22 ± 2.22 hours, 31.38 ± 2.18 hours, and 31.69 ± 2.53 hours, respectively. Experimental CXL groups showed significantly higher ( P < 0.001) resistance to digestion than nonirradiated controls. There was no significant difference in time to digestion across all experimental CXL groups, irrespective of fluence delivered or the absence of oxygen. Conclusions: The resistance to digestion in accelerated high-fluence riboflavin/UV-A CXL is oxygen-independent, which is of particular importance when developing future optimized CXL protocols for corneal ectasia and infectious keratitis. Competing Interests: N. L. Hafezi is the CEO of EMAGine AG, a company producing a CXL device. The remaining authors have no conflicts of interest to declare. (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)
Databáze:	MEDLINE
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