Feasibility of decellularized porcine corneal sheet implantation for a “stromal sandwich” for the treatment of keratoconus and keratectasia

Abstract

Purpose : Keratoconus or keratectasia due to refractive surgery can result in progressive corneal distortion, thus causing reduced visual acuity. Implantation of human corneal lamellar under the corneal flap (stromal sandwich) reportedly suppressed the corneal distortion and increased visual acuity in keratoconus patients (Bilgihan et al., J Cat Ref Surg 2003). In this study, we evaluated the feasibility of using a decellularized porcine corneal sheet for the “stromal sandwich” in a rabbit model.

Methods : Specific pathogen free (SPF) porcine corneal stroma was sliced into a sheet after soaking in ultrapure water for 12 hours to allow swelling. The sheet was decellularized via a supercritical carbon dioxide system, and then sterilized. After a corneal flap was created by microkeratome in 10 rabbit eyes, the porcine corneal sheet was implanted on the stromal bed and the corneal flap was fixed with 3 interrupted 10-0 nylon sutures (n=5). As a control, the corneal flap was fixed without porcine corneal sheet implantation (n=5). For 28-days post surgery, the anterior segment was evaluated by slit-lamp microscopy, central corneal thickness was measured by ultrasound pachymetry, and corneal hysteresis was measured by Ocular Response Analyzer^® (Reichert, Inc., Depew, NY). After 28 days, the corneas were histologically analyzed by hematoxylin/eosin (HE) staining.

Results : Throughout the 28-day follow-up period, slit-lamp microscopy revealed complete corneal transparency in the porcine corneal sheet transplanted eyes and control eyes, and no adverse effects such as corneal flap dislocation or folding, neovascularization, or severe inflammation were observed. At 28-days post surgery, the mean central corneal thickness had significantly increased from 353.8±8.5μm to 424.6±20.2μm (p<0.01). Corneal hysteresis significantly increased from 4.28±0.46mmHg pre surgery to 6.72±0.36mmHg at 28-days post surgery (p<0.01). HE staining showed that the transplanted porcine corneal sheet was present in the corneal stroma without tissue degradation or severe inflammation.

Conclusions : SPF porcine corneal sheet implantation enabled the increase of corneal thickness and hysteresis in a rabbit model. Although further investigation is needed, SPF porcine corneal sheet implantation is potentially applicable for the treatment of keratoconus and keratectasia.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.