Cross-Linking of Human Amniotic Membrane by Glutaraldehyde

Abstract

Purpose: The transplantation of cryopreserved human amniotic membrane has been introduced recently for the reconstruction of the ocular surface. However, in some diseases the transplant usually dissolves rather quickly and early detachment may occur. Therefore, we tried to stabilize the amniotic transplant by applying glutaraldehyde for collagen cross-linking of the membrane. Methods: 18 human amnions were prepared. 4 × 4 cm pieces of amnion were treated with 0.1% glutaraldehyde solution for 30 min. Biomechanical force-elongation measurements were performed and resistance to enzymatic digestion by 0.1% collagenase solution was tested and compared to cryopreserved and untreated fresh amnion. 8 patients with various ocular surface defects were treated with cross-linked amnion and compared to 5 patients with cryopreserved amnion. Results: The force of the amnion cross-linked with glutaraldehyde at 2.5 mm elongation was increased statistically significant by 175% versus fresh amnion and 76.8% versus the cryopreserved amnion. Glutaraldehyde-treated membranes were virtually completely resistant to enzymatic digestion, while fresh and cryopreserved amnions were dissolved completely by day 7. In patients, the cross-linked membrane was preserved for up to 90 days without any signs of dissolution of the membrane and good transparency. Conclusions: Collagen cross-linking using glutaraldehyde leads to a significant increase in the biomechanical strength and enzymatic resistance of amnion, better transparency and less wrinkling. The cross-linked membrane does not dissolve for months and is well suited for the surface reconstruction of the cornea.