Amniotic membrane tranplantation improvements
For those interested in amniotic membrane applications… two studies popped up recently about amniotic membrane (or HAM as they call it, though I can’t quite get used to that acronym) transplantation. I love seeing the developments in what they’re doing with amniotic membrane these days in healing ocular surfaces.
Urea-De-Epithelialized Human Amniotic Membrane for Ocular Surface Reconstruction. (Bandeira et al, Stem Cells Translational Medicine, March 2019.)
This one is about a simple, cheap method to remove the epithelial layer from amniotic membrane prior to transplantation.
The conjunctiva is a clear tissue covering the white part of the eye and lines the back of the eyelids. Conjunctival diseases, such as symblepharon, cause inflammation, discharges, and photophobia. The treatment often requires excision of large parts of conjunctiva. Tissue engineering of conjunctival cells using human amniotic membrane (HAM) denuded of its epithelium as a basement membrane scaffold has been shown to be effective for covering conjunctival defects. However, most epithelial denudation protocols are time-consuming and expensive or compromise HAM's basement membrane structure and matrix components. We have previously described a method to de-epithelialize HAM using ice-cold urea (uHAM). In this report, we used this method to provide tissue-engineered constructs with cultivated conjunctival epithelial cells on uHAM in two patients. The patients presented with a giant conjunctival nevus and a large symblepharon, respectively. Autologous conjunctival epithelial cells harvested from incisional biopsies of these two patients were cultured on uHAM scaffold. The transplantation of tissue-engineered constructs to patients' ocular surface immediately after the removal of lesions showed successful reconstruction of the ocular surface. Postoperatively, there were neither recurrence of lesions nor epithelial defects throughout a follow-up (up to 7 and 19 months, respectively). This report highlights the translational potential of an efficient and inexpensive method to prepare de-epithelialized HAM as a basement membrane scaffold for cell-based tissue-engineered treatments of ocular surface disorders.
Sutureless amniotic membrane transplantation with cyanoacrylate glue for acute Stevens-Johnson syndrome/toxic epidermal necrolysis. (Shanbhag et al, The Ocular Surface, March 2019.)
I know I have a lot of SJS patients on the mailing list with a wide range of severity levels, but SJS in general comprises some of the most challenging and painful dry eye cases. I remember being on the phone with a customer once who told me they were the picture featured on the Wikipedia SJS page. When you see how this disease can ravage the skin, just imagine what it does to mucous membrances like those covering the eyes. This sort of thing makes the rest of us want to be more diligent about counting our blessings.
Amniotic membrane (AM) transplantation, when performed in the acute phase in Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) for patients with ocular complications, is known to reduce the morbidity of ocular complications in the chronic phase. In conditions such as SJS/TEN, AM needs to be secured to the ocular surface as well as the eyelids. Previously, techniques of securing a large sheet of AM with fibrin glue to the ocular surface and with sutures and bolsters to the eyelids have been described in the acute phase of SJS/TEN. These techniques often necessitate the use of an operating room in acutely ill patients. We describe a bedside technique that uses cyanoacrylate glue to secure the AM to the eyelids, as well as long-term outcomes in 4 patients with acute SJS/TEN. The combination of a custom symblepharon ring to secure AM over the entire ocular surface and cyanoacrylate glue to secure AM to the eyelid margins is quick, painless, does not require local or general anesthesia, and might prove useful in other conditions previously shown to benefit from AMT, such as ocular chemical injuries.