Two separate methods of stem cell transplantation in both eyes of a single patient presented with bilateral stem cell deficiency following exposure to Euphorbia latex

Abstract

Limbus is the most dynamic area of ocular surface which is the “home” of stem cells especially in the region of palisades of Vogt. Stem cell deficiency is manifested by ingrowth of vessels into the cornea with resultant corneal haze that results in decreased vision [1]. Stem cell deficiencies are treated by transplantation of stem cells. The methods are varied and includes transplantation from cadaveric tissue, from living related donor (in bilateral cases) and from fellow eye (in unilateral cases). In vitro cultured stem cells in human amniotic membrane (HAM) base may also be utilised. We report here the successful outcome of stem cell implantation in a patient with end stage limbal stem cell deficiency following exposure to the latex of Euphorbia. The Euphorbiaceae family includes trees, succulents and herbaceous plants. Different species of Euphorbia grow all over the world. The milky latex or sap is toxic and may cause intense inflammation of the skin and the eye [2, 3]. Ocular toxic reaction varies from mild conjunctivitis to keratouveitis to severe corneal vascularisation in neglected cases. Ocular toxicity can be caused by three different species of Euphorbia, namely, Euphorbia trigona (African milk tree), Euphorbia neriifolia (Indian Spurge tree) and Euphorbia milii (crown-of-thorns houseplant). In this present case, the patient (female, aged 45 years) with bilateral stem cell deficiency was treated by transplantation of stem cell from living related donor(mother) in the left eye and in vitro cultured stem cell on HAM base in the right eye. A normotensive, non-diabetic, patient (female, aged 45 years) presented to our clinic with loss of vision in both eyes. She gave a history of exposure to Euphorbia latex 5 months back in her both eyes. She neglected the condition and there was gradual decrease in his vision following the brief acute episode. Visual acuity in RE was 1/60, in LE it was finger counting at 2 m. There was no improvement in vision with refractive correction. Schirmer test values in both eyes measured 15 mm. Corneal sensation in both eyes were normal. Intraocular pressure in BE were 18 mmHg and USG (A+B) scans in both eyes were normal. Anterior segment of both eyes revealed 360° limbal vascularisation with diffuse stromal haze up to the extent that anterior chamber details including the pupil is barely visible (Fig. 1). Fig. 1 Right eye showing limbal vascularisation with diffuse stromal haze up to the extent that anterior chamber details including the pupil is barely visible A decision for transplantation of stem cells was made. She was put on systemic steroids (1 mg/kg/day) 3 days prior to admission. From the mother, two separate conjuctivolimbal lenticules were prepared [4 × 2 mm each], one from each eye to reduce chances of development of iatrogenic stem cell loss. The recipient bed in LE was prepared by marking two separate areas: one centred around 6 o’clock hours and the other around 12 o’clock region of the limbus. Peritomy was done and bleeding controlled by cauterisation. The donor lenticules were sutured to the recipient bed with interrupted 10-0 monofilament nylon sutures. In the post-operative period, the patient was put on systemic steroids (1 mg/kg/day) in a tapering dose, topical steroid (pred acetate 1 %), topical antibiotic (topical moxifloxacin) and artificial tears (carboxymethyl cellulose). Both topical and systemic steroids were tapered slowly over a period of 6 weeks and topical antibiotics were withdrawn after the first 2 weeks. The patient was advised weekly visit at the cornea clinic. Four months after the first operation, her RE was operated. Recipient bed was prepared as described before and in vitro cultured stem cells on HAM base were sutured at around 360° of limbus with interrupted 10-0 monofilament nylon sutures. The whole of cornea including transplanted discs were covered by preserved HAM and sutured to adjacent conjunctiva with interrupted 10-0 monofilament nylon. Patient was placed on same post-operative regimen as before. The patient also underwent cataract surgery in both eyes 5 months after her last operation in RE.