title: In vivo analysis of stromal integration of multilayer amniotic membrane transplantation in corneal ulcers.
abstract: OBJECTIVE
  To evaluate integration of amniotic membrane into the corneal stroma using laser scanning in vivo confocal microscopy and anterior segment optical coherence tomography (AS-OCT).
  
  
  METHODS
  Prospective noncomparative interventional case series.
  
  
  METHODS
  Twenty-two eyes of 22 consecutive patients (mean age 53.9 ± 9.2 years) presenting with noninfectious corneal ulcers and stromal thinning unresponsive to medical treatment were enrolled. Multiple layers of amniotic membrane were applied over the ulcer bed to fill the ulcer crater and held in place with an overlying amniotic membrane patch, which was anchored to the surrounding cornea with 10-0 nylon interrupted sutures. Outcome measures were healing of the corneal ulcers, corneal morphology and stromal thickness changes at the ulcer site as measured by AS-OCT and surface epithelialization, stromal repopulation, and structural modifications of the amniotic membrane grafts as evaluated by confocal microscopy.
  
  
  RESULTS
  Follow-up extended to 12 months. Successful result was observed in 20 of 22 eyes (90.9%). AS-OCT showed that the mean residual stromal thickness at the ulcer bed was 222 ± 70 μm before surgery. The mean thickness of amniotic membrane layers at the same site was 394 ± 80 μm while the mean total corneal thickness was 623 ± 51 μm at day 1 post surgery. Thereafter a progressive reduction in thickness to 420 ± 61 μm at 6 months occurred, after which the thickness stabilized. Confocal microscopy showed that integration of the amniotic membrane tissues with corneal stroma was preceded by epithelialization over the amniotic membrane covering the ulcer. This occurred 15 ± 5 days post surgery in the successful cases. Confocal microscopy also showed that the amniotic membrane patch was degraded during the first few weeks after surgery, while the integrated amniotic tissues underwent progressive modifications characterized by early loss of amniotic epithelial cells, changes in fibrillar structure, and migration into the amniotic stroma by corneal stroma-derived cells.
  
  
  CONCLUSIONS
  Multiple layers of amniotic membrane can integrate into the corneal stroma with resulting increase in corneal thickness. This appears to be related to re-epithelialization of the transplanted membrane. Integrated amnion within the stromal defect undergoes progressive changes including contraction of tissue and repopulation by corneal stroma-derived cells.
authors.affiliation: Department of Medicine and Ageing Science, Ophthalmic Clinic, University G. d'Annunzio of Chieti-Pescara, Italy. m.nubile@unich.it
authors.forename: Mario
authors.initials: M
authors.lastname: Nubile
authors.forename: Harminder S
authors.initials: HS
authors.lastname: Dua
authors.forename: Manuela
authors.initials: M
authors.lastname: Lanzini
authors.forename: Marco
authors.initials: M
authors.lastname: Ciancaglini
authors.forename: Roberta
authors.initials: R
authors.lastname: Calienno
authors.forename: Dalia G
authors.initials: DG
authors.lastname: Said
authors.forename: Augusto
authors.initials: A
authors.lastname: Pocobelli
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Mastropasqua
authors.forename: Paolo
authors.initials: P
authors.lastname: Carpineto
mesh_terms: D000328:Adult; D000368:Aged; D000650:Amnion / Q000502:physiology* / Q000637:transplantation*; D001684:Biological Dressings; D003319:Corneal Stroma / Q000378:metabolism* / Q000473:pathology; D003320:Corneal Ulcer / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D011446:Prospective Studies; D012038:Regeneration; D013536:Suture Techniques; D041623:Tomography, Optical Coherence; D014945:Wound Healing; D055815:Young Adult