Ocular surface reconstruction with autologous mucosal membrane transplantation in limbal stem cell deficiency Elisabeth Macdonald Suzannah Drummond Kanna Ramaesh Authors have no financial interest

Background Corneal limbal stem cell deficiency (LSCD) causes corneal opacification and blindness Corneal limbal stem cell deficiency (LSCD) causes corneal opacification and blindness Repopulation with stem cells may occur by transplanting limbal tissue from a donor source or with ex vivo expanded LSC Repopulation with stem cells may occur by transplanting limbal tissue from a donor source or with ex vivo expanded LSC Cultured oral mucosal epithelial cells have previously been used as an alternative to limbal transplantation Cultured oral mucosal epithelial cells have previously been used as an alternative to limbal transplantation

An Alternative ? Mucous Membrane Epithelium Reports of cultured autologous oral mucosal epithelium for LSCD: Nakamura et al. Transplantation of cultivated autologous oral mucosal epithelial cells in patients with severe ocular surface disorders BJO 2004;88: Nakamura et al. Transplantation of cultivated autologous oral mucosal epithelial cells in patients with severe ocular surface disorders BJO 2004;88: Tsutomu et al. Midterm results on ocular surface reconstruction using cultivated autologous oral mucosal epithelial transplantation Am J Ophth 2006;141:267 Tsutomu et al. Midterm results on ocular surface reconstruction using cultivated autologous oral mucosal epithelial transplantation Am J Ophth 2006;141:267 Can the method be simplified by avoiding the cultivation step ? Can the method be simplified by avoiding the cultivation step ? Is direct migration from perilimbal mucous membrane grafts (MMG) possible ? Is direct migration from perilimbal mucous membrane grafts (MMG) possible ?

Why Mucous Membrane? Why Mucous Membrane? Autograft material Autograft material Readily available Readily available Widely used historically to replace abnormal conjunctiva Widely used historically to replace abnormal conjunctiva 1 st use 1876 by Klein 1 st use 1876 by Klein Epithelium similar to corneal epithelium Epithelium similar to corneal epithelium Denig: Textbook of Surgery 1943

Purpose and Methods We describe a novel surgical technique of direct oral MMG to rehabilitate LSCD We describe a novel surgical technique of direct oral MMG to rehabilitate LSCD Direct oral MMG has not been previously reported to restore corneal transparency Direct oral MMG has not been previously reported to restore corneal transparency The results of 5 patients are report The results of 5 patients are report LSCD was characterised by conjunctivalisation of the corneal surface, corneal scarring, recurrent epithelial defects and corneal vascularisation and later confirmed by immunohistochemistry LSCD was characterised by conjunctivalisation of the corneal surface, corneal scarring, recurrent epithelial defects and corneal vascularisation and later confirmed by immunohistochemistry No donor site complications occurred No donor site complications occurred

Surgical technique A 360  peritomy and removal of abnormal epithelium and fibrovascular tissue covering the cornea were performed A 360  peritomy and removal of abnormal epithelium and fibrovascular tissue covering the cornea were performed A small strip of buccal oral mucosa was excised and the sub-stromal adipose tissue removed A small strip of buccal oral mucosa was excised and the sub-stromal adipose tissue removed The mucosal membrane strips were sutured to the exposed perilimbal sclera The mucosal membrane strips were sutured to the exposed perilimbal sclera

Results Baring of the corneal stroma allowed migration of mucous membrane epithelium Baring of the corneal stroma allowed migration of mucous membrane epithelium This produced transparent epithelium on the cornea in 4 cases This produced transparent epithelium on the cornea in 4 cases In one case radial corneal vessels invaded from the periphery In one case radial corneal vessels invaded from the periphery Post OpPre Op

Cases Age Co morbidity Previous ocular reconstruction surgery Pre Op BCVA Post Op BCVA 2yrs Co Pathology 37 Chemical Injury AMGHM3/60 52OCP 2 x failed stem cell grafts, DLK CF6/60CRVO 52OCPNoneCF6/36 61Aniridia Lamellar corneal graft HM6/24 Macula hypoplasia, Optic neuropathy 70OCPConjunctival autograft 6/366/12 Transparent epithelium on cornea

Epithelial cell maintenance The mucosal epithelial cells migrated from the MMG in the perilimbal region onto the cornea to provide a stable corneal surface The mucosal epithelial cells migrated from the MMG in the perilimbal region onto the cornea to provide a stable corneal surface On slit lamp examination the migrated epithelium appeared very similar to normal corneal epithelium and was transparent On slit lamp examination the migrated epithelium appeared very similar to normal corneal epithelium and was transparent The epithelium over the cornea has been maintained and has behaved like ‘corneal epithelium’ The epithelium over the cornea has been maintained and has behaved like ‘corneal epithelium’

The Hypothesis These are derived from resident stem cells of the oral mucosa epithelium These are derived from resident stem cells of the oral mucosa epithelium It is our belief that the success of the technique is due to the survival of the stem cells within the transplanted oral mucosa to the vascular perilimbal location It is our belief that the success of the technique is due to the survival of the stem cells within the transplanted oral mucosa to the vascular perilimbal location These cells may act as a reservoir and generate a progeny of differentiated epithelial cells that cover the cornea These cells may act as a reservoir and generate a progeny of differentiated epithelial cells that cover the cornea Success of ex vivo expanded oral mucosal epithelial transplantation is attributed to the presence of stem cells among the transplanted population Success of ex vivo expanded oral mucosal epithelial transplantation is attributed to the presence of stem cells among the transplanted population

Direct MMG compared with reported cultivated epithelial technique Duration of our results is the same or longer Duration of our results is the same or longer Perilimbal vascular invasion similar Perilimbal vascular invasion similar Advantages of our technique: Advantages of our technique: Much less expensive Much less expensive No need for laboratory No need for laboratory No risk of transmitted disease No risk of transmitted disease

Conclusion New finding New finding Mucosal epithelium migrates from perilimbal grafts to produce functional corneal epithelium Mucosal epithelium migrates from perilimbal grafts to produce functional corneal epithelium Simple and cheap technique Simple and cheap technique Direct autologous perilimbal transplantation of oral mucosal tissue may be an alternative to limbal stem cell transplantation to reconstruct the corneal surface and restore vision in selected cases of severe LSCD Direct autologous perilimbal transplantation of oral mucosal tissue may be an alternative to limbal stem cell transplantation to reconstruct the corneal surface and restore vision in selected cases of severe LSCD