Advances in corneal stem-cell transplantation in rabbits with severe ocular alkali burns (original) (raw)
Related papers
2020
Objectives: This study compares the efficacy of stem cell transplantation in corneal regeneration and restoration of the limbic deficit in an experimental chemical burn in rabbits. Methods: The biopsy of limbus and the chemical burn were performed in all rabbits, and the amniotic membranes were obtained from a pregnant rabbit. A control group without transplantation, to study spontaneous and natural healing, and transplanted the stem cells produced in vitro under the corneal epithelium burned. To compare the result, a group was tested for amniotic stem cell transplantation, a group for limbal stem cell graft, and another group for combined transplantation of both types of stem cells. Results: Transplanted rabbits develop permanent unilateral blindness due to a severe limbic deficit. The group receiving only amniotic stem cells shows temporary anatomical improvement without functional recovery. The two groups receiving limbal stem cells alone or combined with amniotic stem cells show...
Regenerative Approaches and Future Trends for the Treatment of Corneal Burn Injuries
Journal of Clinical Medicine, 2021
Ocular chemical and thermal burns are frequent causes of hospitalization and require immediate interventions and care. Various surgical and pharmacological treatment strategies are employed according to damage severity. Controlling inflammation and neovascularization while promoting normal ocular surface anatomy and function restoration is the principal aim. In the most severe cases, when epithelial healing is severely affected, reconstruction of the ocular surface may be a valid option, which, however, requires expertise, adequate instruments, and qualified donors. Numerous endogenous and exogenous strategies have been considered for corneal repair. Among these, stem cells and their derivatives have offered numerous attractive possibilities in finding an effective way in stimulating corneal regeneration. Limbal epithelial stem cells and mesenchymal cells from the ocular tissue as well as from various sources have demonstrated their effectiveness in dampening neovascularization, sca...
2002
Purpose. To describe the histopathologic changes in the cornea following amniotic membrane transplantation (AMT) combined with limbal transplantation. Methods. Four eyes with complete limbal stem cell deficiency after severe chemical burn underwent AMT with either a living-related conjunctival limbal allograft (lr-CLAL) (three eyes) or a conjunctival limbal autograft (CLAU) (one eye) for ocular surface reconstruction. Penetrating kerato-plasty was performed several months after the initial procedure for further visual rehabilitation. Mean follow up time was 20 months. Light and transmission electron microscopy (TEM) and indirect immunofluorescence microscopy of the excised corneal buttons were performed. Results. All specimens displayed a multilayered epithelium without conjunctival goblet cells over the entire corneal surface. Basal epithelial cells demonstrated a firm connection to the remnants of the transplanted amniotic membrane (AM), which at some places appeared to be in a state of "modification" or "remodeling" in the collagen layers. The basement membrane zone displayed a positive staining when using antibodies against colla-gen IV and VII, integrin ␣6 and 4, laminin 5, and bullous pem-phigoid antigen 2. Remnants of the AM in the specimen showed staining of collagen IV, which was found also in cross-sections of cryopreserved AM. The recipients Bowman's membranes that were only partially present after the initial trauma were significantly disturbed. Conclusion. Within the time frame studied, the transplanted AM apparently survives and integrates into the host tissue being modified or remodeled by recipient cells. AMT in combination with a CLAU or lr-CLAL is a useful technique in promoting a rapid and stable reepithelialization of a corneal surface following severe chemical or thermal damage. NB added: The ACADEMIA.edu-upload-System DOES NOT allow to insert FIRST AUTHOR('s) or Co-Authors' names even if they CANNOT have an official / institutional e-mail-address due to their retirement or leaving academic institution.
Journal of Stem Cell Biology and Transplantation
Background: Corneal injury commonly caused by chemical agents. Alkali agents affect corneal clarity and impaired visions with defective treatments. Bone marrow mesenchymal stem cells (BM-MSCs) are multipotent self-renewal cells which give challenge for many diseases. The aim of the work: Is to study the role of BM-MSCs as therapeutic modality on alkali-induced corneal injury in rats. Material and methods: Thirty adult male albino rats had been divided into three equal groups: 1-Group I as a control. 2-Group II (bilateral alkali-burnt corneas) and received 200 mg/kg cyclophosphamide to induce bone marrow-suppression also, divided into: subgroup IIa, bone marrow suppressed without MSCs treatment; subgroup IIb, bone marrow suppressed with MSCs treatment. 3-Group III (bilateral alkali-burnt corneas) as normal bone marrow function and divided into: subgroup IIIa, normal bone marrow function, without MSCs treatment; subgroup IIIb, normal bone marrow function, with autologous MSCs treatment. Results: Corneas of alkali burn rats with CP without MSCs treatment revealed degeneration with loss of the superficial epithelial cells and corneal neovascularization with stromal separation, interstitial hemorrhage and cellular infiltration. While in sub group IIIa, produced moderate changes compared with subgroup IIa. In corneas of alkali burn rats treated with MSCs and received CP produced slight improvement, while those treated with MCSs without CP for 2 weeks after alkali burn showed nearly normal histological and ultrastructural pictures. Conclusion: MSC transplantation could ameliorate corneal healing in rats in alkaliinduced the corneal ulcer.
Induction of corneal collagen cross-linking in experimental corneal alkali burns in rabbits
Arquivos Brasileiros de Oftalmologia, 2014
Eye burns are common and may be caused by various chemical and physical agents including acids, alkalis, high temperatures, and fire (1). They are most generally a consequence of chemical handling accidents and may result in permanent damage to the ocular surface and visual function (1). Corneal alkali burns are considered an ophthalmologic emergency. Therefore, timely recognition and implementation of the appropriate treatment represent important steps in controlling the progression of early and late complications (2). The literature describes various forms of treatment for corneal alkali burns. These include artificial tears, collagenase inhibitors, therapeutic contact lenses, topical fibronectin, topical vitamin C, topical citrate (2) , conjunctival transplantation (1) , amniotic membrane patching (3,4) , limbal transplantation (5) , and autologous serum eye drops (6) as well as treatment of the severe inflammatory processes with topical or systemic corticosteroids.
Artificial Organs, 2006
The purpose of this article was to evaluate the graft efficacy of reconstructed corneal layer, composed of autologous corneal epithelium and fibroblasts on a lyophilized amniotic membrane (LAM), in a severely alkaliburned corneal model. After biopsy specimens were obtained from the left eyes of 24 rabbits, the corneal epithelial cells and fibroblasts were expanded in vitro and the corneal layer was reconstructed on LAM. Thirty-six eyes of rabbits underwent alkali burn (1 N NaOH, 30 s) to create a limbal deficiency and a deeply damaged corneal stroma. Four weeks later, group 1 underwent a graft of the reconstructed corneal layer composed of autologous corneal epithelium and fibroblasts on LAM. Group 2 was transplanted with a graft of the reconstructed autologous corneal epithelium, and group 3 served as a control without surgery. Wound healing and stabilization of the ocular surfaces occurred much faster in group 1 than in groups 2
Endothelial healing in rabbit corneal alkali wounds
Acta Ophthalmologica, 2009
The healing of rabbit corneal endothelium was studied following a standardized corneal alkali burn. The excised corneas were stained and examined, flat mount, endothelial side up, in the light microscope. Morphometric determinations were performed during the healing process by flat mount technique, and endothelial cell morphology was studied by both histological and flat mount techniques. The decrease of the endothelial wound diameter was linear, in the order of 18 ym/h, during the first 5 days. By one week the wound was almost completely covered by endothelial cells. Subsequently, the endothelium broke down in the central wound area during the second week. Endothelial healing resumed after the secondary break down although at a slow pace. The healing was often interfered with by invading fibroblast-like cells. The endothelial wound was not completely covered by endothelial cells even 6 months after trauma. The interrelation of the damage in different layers of the cornea was discussed.
Concise review: the coming of age of stem cell treatment for corneal surface damage
Stem cells translational medicine, 2014
The cornea is a vital component of the eye because it provides approximately 70% of the refraction and focusing of incoming light. Being the outermost surface of the eye, it faces continuous stress from dryness, photodamage, infection, and injury; however, like the skin, the cornea regularly refreshes itself by shedding its epithelial cells, which are readily replaced, keeping the ocular surface stable and functional. This regular turnover of the corneal epithelial cells occurs through the stem cells in the limbus, an annular ring of a tissue surrounding the cornea, separating it from the sclera and the conjunctival membrane. The loss of this reserve of stem cells leads to a condition called limbal stem cell deficiency. Treatment for this disorder has evolved from transplanting whole limbal tissues to the affected eye to transplanting laboratory cultured limbal cells. This procedure is called cultivated limbal epithelial transplantation (CLET). Since its start in 1997, more than 1,0...