SCIENTIFIC CORRESPONDENCE Amniotic membrane grafts, “fresh” or frozen? A clinical and in vitro comparison

Background/aims—The use of “fresh” (hypothermically stored) and frozen amniotic membrane (AM) was compared in a patient with cicatricial pemphigoid with stem cell failure. The viability of both “fresh” and frozen AM epithelial cells was assessed after storage. Methods—AM was stored at either +4°C (“fresh”) or at −80°C (frozen). A “fresh” graft was applied to the cornea following superficial keratectomy. Subsequently, a further frozen graft was applied to the same eye. Viability of the stored AM epithelium was assessed by investigating membrane integrity and mitochondrial activity. Results—In both cases the cornea reepithelialised and visual acuity improved. Improvement, however, was not sustained. Conclusion—Although both procedures led to an improvement in visual acuity, “fresh” tissue performed no better than frozen in promoting re-epithelialisation. The authors suggest that logistical, safety, and cost considerations outweigh any benefits of using “fresh” as opposed to frozen graft material. (Br J Ophthalmol 2001;85:905–907) Amniotic membrane has been used sporadically for many years in a variety of clinical applications. 2 Recently, there has been a resurgence of interest in amniotic membrane transplantation for ocular surface reconstruction. Various methods have been used to preserve amniotic membrane including “fresh” (or more appropriately hypothermic) storage, freezing, and freeze drying. Maintenance of the integrity of the basement membrane and stromal matrix appears to be central to promoting rapid re-epithelialisation, and storage conditions were chosen to optimise