Autologous transplantation of conjunctiva by modifying simple limbal epithelial transplantation for limbal stem cell deficiency

Simple Epithelial Transplantation for Ocular Surface Reconstruction After Severe Ocular Burn Injury

PURPOSE

To manage ocular surface complications and recover conjunctival and corneal epithelia after unilateral severe chemical burn.

METHODS

We performed simple conjunctival epithelial transplantation (SCET) to obtain renewal of fornix and bulbar-tarsal conjunctiva epithelium, followed by simple limbal epithelial transplantation (SLET) to recover limbal function and epithelial corneal surface. Slit-lamp examination, fluorescein staining, in vivo confocal microscopy, Kheirkhah grading system for symblepharon severity, Wong-Baker FACES Pain Rating Scale, and best-corrected visual acuity were assessed before surgery, at 1 to 3 months after SCET and SLET, and thereafter at 6 to 12 to 36 months.

RESULTS

Two patients with unilateral burn injuries underwent surgery. Eye mobility and fornix reconstruction were promptly achieved, and conjunctival epithelium with goblet cells was observed on the bulbar and tarsal conjunctiva 3 months after SCET. After SLET, corneal epithelium and cornea-conjunctiva transition zone were observed at 3 and 6 months, respectively. From before surgery to 6 months after SLET, symblepharon improved from grade IVa2 and IIIb2 to Ic0 and Ib0, the Wong-Baker FACES Pain Rating Scale changed from grade 6 and 4 to 0, and best-corrected visual acuity upgraded from 1.40 and 1.10 logarithm of the minimum angle of resolution to 0.5 logarithm of the minimum angle of resolution, in patient 1 and 2, respectively. After 3 years, results remained stable.

CONCLUSIONS

SCET effectively healed the bare conjunctival area relieving subjective symptoms and discomfort. Sequential SCET and SLET showed to be feasible in restoring a normal ocular surface with long-lasting results suggesting the aim in patients with severe ocular burn is not merely corneal epithelium renewal but also the regeneration of ocular surface homeostasis.

Amniotic Membrane Transplantation: Clinical Applications in Enhancing Wound Healing and Tissue Regeneration

Chronic wounds and non-healing tissue defects pose significant clinical challenges, necessitating innovative therapeutic approaches. A comprehensive literature review of amniotic membrane transplantation for wound healing and tissue repair evaluates the efficacy and safety of amniotic membrane transplantation in enhancing wound healing and tissue repair. Amniotic membranes promote wound closure and reduce inflammation and scarring via abundant growth factors, cytokines, and extracellular matrix components, which foster conducive environments for tissue regeneration. Amniotic membrane transplantation is effective in various medical disciplines, including ophthalmology, dermatology, and orthopedics. Low immunogenicity and anti-microbial properties ensure their safe application. Amniotic membrane transplantation offers a promising therapeutic approach for wound healing and tissue repair, and further research is warranted to explore its regenerative potential fully.

Corneal regeneration strategies: From stem cell therapy to tissue engineered stem cell scaffolds

Corneal epithelial defects and excessive wound healing might lead to severe complications. As stem cells can self-renew infinitely, they are a promising solution for regenerating the corneal epithelium and treating severe corneal epithelial injury. The chemical and biophysical properties of biological scaffolds, such as the amniotic membrane, fibrin, and hydrogels, can provide the necessary signals for stem cell proliferation and differentiation. Multiple researchers have conducted investigations on these scaffolds and evaluated them as potential therapeutic interventions for corneal disorders. These studies have identified various inherent benefits and drawbacks associated with these scaffolds. In this study, we provided a comprehensive overview of the history and use of various stem cells in corneal repair. We mainly discussed biological scaffolds that are used in stem cell transplantation and innovative materials that are under investigation.

ALT (allogeneic limbal transplantation): a new surgical technique for limbal stem cell deficiency

Purpose

Limbal stem cell deficiency (LSCD) is a rare but extremely relevant disease of the eye. LSCD patients often require a variety of surgical procedures, including keratoplasty in some cases. However, the outcome of these surgeries, including opacification and revascularization, is often frustrating due to LSCD relapse.

Methods

We developed a new surgical technique for the treatment of LSCD in which partial allogenic limbal transplantation (ALT) is carried out as part of penetrating keratoplasty (PK). After the PK, 1–8 slices from the limbal tissue of the donor graft are prepared and placed under the double running sutures attaching the corneal graft. This procedure was performed on 14 patients with LSCD, caused by severe ocular burn in 5 cases and by infection in 9. Between one and eight limbal transplants were used depending on the extension of the LSCD.

Results

All 14 patients showed stable or increased visual acuity after the ALT surgery compared to their preoperative visual acuity. All of the grafts were integrated into the superficial corneal layers without progression of corneal vascularization beyond the limbal grafts. The median follow-up period was 12 months on average.

Conclusion

The ALT method seems to be a promising surgical procedure for the treatment of patients with LSCD. It can be properly carried out in the context of keratoplasty and does not require a separate donor tissue. The ALT grafts may offer the possibility of constructing a new limbal region, resulting in stable or even increased visual acuity and the absence of corneal vascularization.

Effects of corneal epithelial superficial keratectomy in patients with focal limbal stem cell disease

Purpose

Irregular corneal epithelium in limbal stem cell disease can cause visual acuity to deteriorate substantially when it reaches the pupil. In this case series, we assessed the effectiveness of simple corneal epithelial superficial keratectomy in improving visual acuity in patients with irregular corneal epithelium in focal limbal stem cell disease covering the visual axis.

Observations

We performed simple corneal epithelial superficial keratectomy in four patients (five eyes) with irregular corneal epithelium covering the visual axis. The main outcome measures were best-corrected visual acuity, slit lamp findings with fluorescein staining, anterior segment optical coherence tomography and histopathology. In all five eyes, slit lamp findings showed uneven fluorescein staining in a spiral pattern, with impaired corneal epithelial smoothness and visual disturbance. We removed the irregular epithelium in all five eyes. Visual acuity in all the eyes was improved immediately after surgery, and good visual acuity and stable epithelium were maintained for the duration of the observation periods. Hematoxylin and eosin staining showed, normal squamous and columnar epithelial cells. Goblet cells were not detected.

Conclusionsand Importance

Corneal epithelial superficial keratectomy can lead to a pathological diagnosis by examining the removed epithelial tissues, and result in excellent therapeutic outcomes in focal limbal stem cell disease reaching the pupil.