The application of tissue engineering in reversing mitomycin C‐induced ischemic conjunctiva

Abstract

The purpose of this study is to evaluate the angiogenic potential of collagen-glycosaminoglycan (CG) matrices in mitomycin C-induced ischemic conjunctival defect, in New Zealand white rabbits. After creating a conjunctival defect at the center of ischemic conjunctiva, a CG matrix was implanted into subconjunctival space to evaluate the conjunctival reepithelialization and angiogenesis during the wound healing process. In the grafted group, the vessel count of the healed conjunctiva was substantially elevated by two fold within the initial 4 weeks and the increased vascular content originated mostly from the fornix site. The rate of conjunctival reepithelialization was not retarded in the grafted group, and the final thickness of healed conjunctiva was similar in both grafted and ungrafted groups. The histological studies revealed that the collagen matrix did not elicit pronounced inflammatory reaction and the regenerated conjunctiva showed loosely arranged collagen deposition without significant scar formation. The α SMA staining positive myofibroblasts were identified in the acute inflammatory stage and were absent, 8 weeks after implantation in both groups. The results indicated that the porous collagen scaffold was able to enhance vascularization and physiological recovery of ischemic conjunctival defect, implying a potential alternative therapy for the ischemic leaking bleb after glaucoma filtrating surgery in ophthalmic practices.

Secondary subconjunctival implantation of a biodegradable collagen-glycosaminoglycan matrix to treat ocular hypotony following trabeculectomy with mitomycin C

“…As CGM implants are also thought to promote angiogenesis and to counteract the ischaemic complications of the antimetabolite mitomycin C following glaucoma surgery,8 secondary implantation of collagen matrix implant in post-trabeculectomy eyes with ocular hypotony should present a useful combined mechanical and biological approach to limiting overfiltration.…”

“…An animal study about the treatment of a mitomycin C-altered conjunctiva by CGM use has demonstrated by histology that an inflammatory response around and inside the matrix had taken place at day 7 postoperatively and that the use of the CGM had improved vascularity in a previously avascular area at week 4 8. However, the authors found the time needed for epithelial closure of an experimental wound or attainment of final conjunctival thickness to be independent of whether or not CGM was used.…”

“…In the midterm and long term, the induction of regular fibroblast ingrowth and improvement of vascularisation, especially in the avascular bleb,8 should re-establish sufficient outflow resistance to prevent ocular hypotony. Either mechanism of action is possible with the biodegradable collagen-glycosaminoglycan matrix (CGM) that was introduced to ophthalmosurgery several years ago 9–14…”

Letter to the Editor: The O-arm revolution in spine surgery

“…3,7,[9][10][11]13,15 For example, Kim 5 used MMC eye drops (0.0002 mg/ml) 4 times daily for 2-5 days after regional conjunctivectomy for chronic conjunctival injection. Conjunctival epithelial defects persisted up to 27 months (mean 13.65 months) after the surgery and produced many complications such as thinning of the sclera or avascular necrosis of the sclera in as many as 92% of the patients.…”

“…In the field of neurooncology, several research studies have already demonstrated the benefits of intraoperative imaging (either with ultrasonography 21 or, more markedly, with high-field intraoperative MRI 1 ) as adjuvant techniques that may provide a more accurate evaluation of the extent of tumoral resection. Similarly, in vascular neurosurgery, the use of intraoperative angiography 11 and, more recently, the developments of indocyanine green videoangiography 10 have also substantially contributed to improving the quality of the neurosurgical procedures for intracranial aneurysms and arteriovenous malformations.…”