# Xenogenic Corneal Lenticules (XENIA) – Biomechanical Characterization and Enzymatic Resistance Analysis

## TL;DR

This study shows that processed pig corneal tissue (XENIA) is much stiffer and more resistant to digestion than human or pig corneal tissue, making it a promising alternative for corneal treatments.

## Contribution

The study introduces XENIA-lenticules as a novel xenogenic corneal augmentation material with superior biomechanical and enzymatic resistance properties.

## Key findings

- XENIA-lenticules are 23.5-fold stiffer than porcine lenticules at 11% strain.
- XENIA-lenticules showed only 19.2% digestion after 20 days, compared to complete digestion of human samples within 11 hours.
- Human lenticule stiffness strongly correlates with donor age (rs = 0.941).

## Abstract

Decellularized and cross-linked porcine stromal tissue offers a new option for corneal tissue augmentation. The aim of this study is to characterize the biomechanical properties and enzymatic resistance of processed xenogenic porcine corneal lenticules (XENIA) and compare them to human/porcine specimens.

Groups of XENIA, human, and porcine corneal lenticules were formed. The dimensions of all lenticules were 7.7 mm in diameter and 80 µm in thickness. Conformité Européenne (CE)-approved XENIA-lenticules were provided by the manufacturer and human/porcine lenticules were generated using a femtosecond laser from the anterior stroma of cadaver eyes. All specimens were analyzed by uniaxial stress-strain measurements (n = 6 per group) and the resulting elastic moduli were compared. To evaluate the enzymatic resistance, all lenticules (n = 5 per group) were treated with collagenase solution (c = 0.1 U/mL) over a 20-day period and the lenticule size was analyzed by photo-documentation.

XENIA-lenticules showed the highest elastic modulus, significantly higher than human and porcine lenticules. At 11% strain, the maximum difference occurred between XENIA and porcine lenticules, with XENIA-lenticules being 23.5-fold stiffer. In the human lenticule group, donor age correlated strongly with the elastic moduli of this group (rs = 0.941, P = 0.005). XENIA-lenticules showed the greatest resistance against enzymatic digestion. On average, human samples were completely digested after 11 ± 4 hours, porcine samples after 91 ± 60 hours, whereas XENIA-lenticules only showed a digested area of 19.2% ± 13.7% after 20 days.

XENIA-lenticules are substantially stiffer (3.9–9.6-fold stiffer than human tissue and 9.0–23.5-fold stiffer than porcine tissue across 5% to 17% strain) and resistant to enzymatic digestion compared to human/porcine probes.

XENIA-lenticules may help to overcome the lack of human corneal donor tissue and may offer new alternatives for corneal augmentation therapies, such as for corneal melting or keratoconus.