Amniotic membrane graft: Histopathological findings in five cases

Abstract

Amniotic membrane transplantation (AMT) is an effective treatment for ocular surface reconstruction; however, the mechanisms through which amniotic membrane (AM) exerts its effects as well as its fate after transplantation have not been entirely elucidated and have been investigated only in part. We evaluate the integration of AM in the host cornea in five patients who underwent AMT as the result of Bowen's disease, band keratopathy, radio- or cryotherapy-induced keratopathy, chemical burn or post-herpetic deep corneal ulcer with descemetocele. Due to persistent opacification in four cases and a progressing tumor in one case, penetrating keratoplasty (PK) and enucleation were performed as early as 2 months and up to 20 months after AMT. The corneas were analyzed histopathologically. To evaluate AM remnants, corneas were stained with periodic acid Schiff's reaction (PAS), Alcian blue, and Gomory and Masson trichrome; immunostaining including collagens III and IV antibodies was also performed. None of the corneas showed remnants of AM. In all cases, we observed discontinuity of Bowman's membrane. In three cases, the corneal epithelium was completely restored, ranging from three to six cell layers. In the other two cases, we detected an intense inflammatory reaction with rich neovascularization; the epithelial surface of the central cornea was completely restored, while at the periphery of the cornea goblet mucus-producing cells were present. Although clinically useful in all cases, restoration of a stable corneal epithelium through AMT is limited by the extent and severity of limbal stem cell deficiency (LSCD). The lack of histologically documented AM remnants in our cases seems to explain the efficacy of AMT more through its biological properties than through its mechanical properties.

Long-Term Results of Amniotic Membrane Transplantation for Partial Limbal Deficiency

“…[16][17][18] We could not address this issue in our study. We presumed that even if amniotic membrane remnants were to remain on the cornea, their presence would be insufficient to prevent recurrence.…”

Postoperative Changes in Amniotic Membrane as a Carrier for Allogeneic Cultured Limbal Epithelial Transplantation

“…14 In infective corneal diseases, the transplantation of a multilayer amniotic membrane can increase the thickness of the corneal stroma and avoid complications such as ulcer perforation. [26][27][28][29][30] In this study, corneal OCT showed gradual thinning of the amniotic membrane in the 12 eyes with stable ocular surfaces. Discontinuity of the amniotic membrane was observed at 4 months after cultivated limbal epithelial transplantation and became more evident at 1 year.…”

Comparative Evaluation of Phototherapeutic Keratectomy and Amniotic Membrane Transplantation for Management of Symptomatic Chronic Bullous Keratopathy

“…It was found that none of the eyes showed remnants of AM in the cornea, and Bowman membrane was disrupted in all cases. 19 The authors concluded that the efficacy of AMT was more through its biological properties than through its mechanical properties. 19 Complications that can occur after AMT include hematoma formation in the postoperative period, 20 granuloma formation, or premature degradation of the membrane requiring a repeat procedure.…”

“…In one study, 19 5 eyes that underwent AMT and subsequent penetrating keratoplasty or enucleation were subjected to histopathological analysis. It was found that none of the eyes showed remnants of AM in the cornea, and Bowman membrane was disrupted in all cases.…”