Stem Cells Therapy for Corneal Blindness (ExCell)

This is a investigative initiated, comparative pilot clinical trial to ascertain the safety of application of ex-vivo cultivated limbal stem cells in human eyes for treating different superficial corneal pathologies. Pre-clinical work in murine models have already demonstrated efficacy of this technique in curing murine corneal pathologies.

In this prospective interventional study patients with superficial corneal pathologies like scars, ulcers and burns will undergo a surgical procedure. Limbal ring from a cadaveric donor tissue, which is therapeutically accepted and serologically tested, is collected. This tissue will then be cultivated in the stem cell biology laboratory using standardized culture technique. Briefly the limbal tissue will be cut up into small pieces and digested overnight using an enzyme (Collagenase L). The cells obtained from the digest will be cultured on a petri-dish using 2% serum and growth factors. The cultured cells will be passaged three times to remove all epithelial cells from the culture. In the second procedure, the central corneal epithelium will be removed using a surgical sponge. 0.1ml of stromal cells in a concentration of 5x10^3 cells/uL diluted in the thrombin component of fibrin glue (TISEEL, Baxter) will be applied to the debrided corneal stroma. A soft bandage contact lens will be placed over the cornea at the end of the procedure. The patient will receive topical antibiotic and steroid eye drops in the post-operative period. Periodic comprehensive ophthalmic evaluation along with anterior segment optical coherence tomography (ASOCT) scanning and slit-lamp photography will be done at day 1, day 7, day 45 and day 90.

0.5 million stromal and epithelial cells will be incorporated in 0.05ml of commercially available fibrin glue and pasted over the corneal lesion after epithelial debridement.

0.5 million stromal and epithelial cells will be incorporated in 0.05ml of commercially available fibrin glue and pasted over the corneal lesion after epithelial debridement.

Checking for the improvement in visual acuity that will be calculated using LogMAR chart (where 20/20 vision is normal).

Inclusion Criteria: Male and Female participants who are aged between 18-60 years. Patients who are having with unilateral blindness due to superficial (defined as involving the anterior 200 microns of the corneal stroma on ASOCT imaging) corneal wounds, ulcers, burns and scars. Eyes with otherwise normal. Exclusion Criteria: Active infection, proven by microbiology. Unknown etiology, post-herpetic eye disease or eyes with active intra-ocular inflammation. Children (<18 years of age). Inability/refusal to give written informed consent or to undergo any of the anterior segment imaging tests.

Basu S, Hertsenberg AJ, Funderburgh ML, Burrow MK, Mann MM, Du Y, Lathrop KL, Syed-Picard FN, Adams SM, Birk DE, Funderburgh JL. Human limbal biopsy-derived stromal stem cells prevent corneal scarring. Sci Transl Med. 2014 Dec 10;6(266):266ra172. doi: 10.1126/scitranslmed.3009644.

Basu S, Damala M, Singh V. Limbal Stromal Stem Cell Therapy for Acute and Chronic Superficial Corneal Pathologies: Early Clinical Outcomes of The Funderburgh Technique. Investigative Ophthalmology & Visual Science. 2017 Jun 23;58(8):3371-337