Autologous ex Vivo Conjunctival Epithelial Cell Expansion for Ocular Surface Transplantation
Condition: Pterygium; Ocular Surface Disease; Stevens Johnson Syndrome; Chemical Injury
MeSH terms: Stevens-Johnson Syndrome; Pterygium
Study type: Interventional
Phase: Phase 3

Summary: 
      To evaluate the use of cultivated conjunctival epithelial equivalents for the treatment of
      ocular diseases
    

Detailed description: 
      Ex-vivo autologous conjunctiva expansion on human amniotic membrane (HAM), followed by
      clinical transplantation surgery

      Preparation of HAM. Human amniotic membrane (HAM) prepared for human use will be obtained
      from the Singapore Eye Bank. HAM will be rapidly thawed in a 37oC water bath, and washed with
      phosphate buffered saline. The amniotic epithelium will be removed using a combination of
      Dispase digestion and mechanical scraping. Complete removal of the amniotic epithelial cells
      will be confirmed by microscopy. The HAM is then placed on a culture plate, with the
      basement-membrane side up, and incubated with DMEM at 37oC in an atmosphere of 5% CO2 and 95%
      air overnight before use.

      Ex-vivo expansion of conjunctival cells on HAM. A forniceal conjunctival biopsy will be
      performed in patients undergoing pterygium surgery. The tissue will be cultured on the HAM
      either as a cell suspension or as explants, with the methods described above. The media is
      changed every 2 days and the culture is maintained for 2-3 weeks. The cells will form a
      confluent sheet and begin to stratify and differentiate. The tissue will then be raised to an
      air-liquid interface to promote differentiation.

      Histological analysis. The conjunctival epithelial cell sheets on the amniotic membrane will
      be examined by light microscopy. Samples of the tissue will be fixed and processed with the
      use of standard histological procedures and stained with H&E and PAS reagents. Electron
      microscopic examination will be carried for the tissue. The sections will also be subjected
      to immunohistochemical analysis for cytokeratin markers.

      Clinical Transplantation of cultivated conjunctival epithelial cells on HAM

      Preparation of cultivated conjunctival cells on amniotic membrane Patients with various
      ocular surface disorders will be selected for the initial series of transplantations. All
      patients will undergo full counselling for informed consent for the procedures. A forniceal
      conjunctival biopsy will be performed on the contralateral healthy eye. PI will perform the
      transplantations of autologous conjunctival sheet grown on human amniotic membrane in these
      patients. The diseased area will be excised using the standard surgical technique. The defect
      will be covered with the sheet of cultured conjunctival cells on the HAM with the epithelial
      side up. The graft is secured to the adjacent conjunctiva with interrupted 8/0 vicryl
      sutures. A planotherapeutic bandage contact lens is placed to protect the tissue from lid
      trauma. Topical steroid and antibiotic eyedrops will be administered daily to reduce the
      ocular inflammation. Survival of conjunctiva on the amniotic membrane will be closely
      monitored and patients will be followed-up at 3 monthly intervals up to one year. During
      these visits, these patients will have anterior segment photographs taken and fluorescein
      staining to monitor the progress of healing.

      Transplantations may also be carried out on selected patients with ocular surface disease,
      for example, ocular cicatricial pemphigoid, Stevens Johnson syndrome and alkali injury. For
      these severe conditions, this procedure may prove to be an important adjunct to other
      procedures, such as limbal stem cell transplantation. If the initial study is successful, a
      randomised clinical trial comparing this procedure with conventional conjunctival
      autografting and conventional amniotic membrane transplantation will be planned. Therefore if
      found to be successful, transplantation of cultured conjunctival cells on HAM may eventually
      be used as a primary procedure or as an adjunctive procedure for these visually debilitating
      conditions.
    

Intervention name(s): Cultivated conjunctival transplantation
Intervention type(s): Procedure
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Culture; Conjunctiva; transplantation; pterygium; ocular surface