ABSTRACT
PURPOSE: To evaluate the feasibility and effects of the intrastromal implantation of chemically modified corneal stroma obtained from chicken into the corneas of rabbits for corneal thickening. METHODS: Chicken corneas were cut, debrided, treated with cross-linking and implanted in an intrastromal pouch created in the cornea of 10 white New Zealand rabbits with femtosecond laser. Slit-lamp biomicroscopy and optical coherence tomography were performed immediately, 7, 30 and 90 days postoperatively. Corneas were removed at 90 days and cut in two halves. One half was sent to histological analysis for the presence of necrosis, polymorphonuclear inflammatory cells, blood vessels and fibrosis, while the other half was evaluated with transmission electron microscopy to verify tissue organization and the presence of keratocytes and inflammatory cells. Corneal thicknesses were comparatively analyzed over time with Wilcoxon test (p ≤ 0.05). RESULTS: The chicken grafts were incorporated into the cornea of all animals over time. Mean rabbit cornea thickness increased from 338 µm preoperatively to 538 µm (p < 0.0077) at 90 days, while mean chicken graft thickness decreased from 350 to 215 µm (p < 0.0077). No clear signs of rejection attributable to the xenograft were observed in any of the implanted eyes. However, some macroscopic and histological events were observed in some of the eyes, probably due to procedural issues during implantation. CONCLUSION: The intrastromal implantation of chicken grafts was shown to be feasible and predictable to thicken the recipient rabbit cornea without apparent rejection. However, before being considered in humans, further meticulous clinical trials are required to establish the clinical utility, safety and efficacy of xenografts for the treatment of patients with advanced keratoconus.
Subject(s)
Corneal Transplantation , Keratoconus , Animals , Chickens , Cornea/surgery , Corneal Stroma/surgery , Humans , RabbitsABSTRACT
OBJETIVO: Avaliação corneana pós-operatória com a utilização de crosslinking com dois equipamentos distintos. MÉTODOS: Dois grupos de pacientes: grupo A com 36 olhos e grupo B com 19 olhos foram submetidos ao tratamento por crosslinking de colágeno corneano para estabilização de ceratocone. No grupo A foi utilizado o equipamento Crosslink (IROC - Alemanha) e no grupo B o equipamento X-link (Opto - Brasil). RESULTADOS: Foi avaliado o tempo de reepitelização corneana, acuidade visual, biomicroscopia, topografia, tomografia corneana e microscopia especular após uma semana, 1 mês, 3 meses e 1 ano após os procedimentos cirúrgicos. Não houve diferença significativa na avaliação entre os dois grupos. CONCLUSÃO: O resultado pós-operatório nos dois grupos foi semelhante.
OBJECTIVE: Postoperative corneal assessment after using two different types of crosslinking equipment METHODS: Two groups of patients, group A with 36 eyes, and group B with 19 eyes, were submitted to the treatment for the stabilization of keractoconus by corneal collagen crosslinking. In group A the equipment used was Crosslink (IROC - Germany), while in group B the equipment was used was Xlink (Opto - Brazil). RESULTS: Corneal reepithelization time, visual acuity, biomicroscopy, topography, corneal tomography and specular microscopy were assessed at 1 week, 1 month, 3 months, and 1 year after the surgical procedures. No significant differences were found in the assessment between the two groups. CONCLUSION: The postoperative results of both groups were similar.
