Corneal regeneration

Li F, Griffith M, Li Z, Tanodekaew S, Sheardown H, Hakim M, Carlsson DJ. Recruitment of multiple cell lines by collagen-synthetic copolymer matrices in corneal regeneration. Biomaterials 26 3093-3104 (2005). 

JM Wolosin. (1988). Regeneration of resistance and ion transport in rabbit corneal epithelium after induced surface cell exfoliation. J Membr Biol 104 45-55. 

High concentrations of vapor cause conjunctival irritation and blepharospasm. Liquid chloroform splashed in the eye causes immediate burning pain and conjunctival irritation the corneal epithelium may be injured, but regeneration is prompt, and the eye returns to normal in 1-3 days. Applied to the skin, chloroform causes burning pain, erythema, and vesiculation. ... 

Nevertheless, the stroma might also have some ability to regenerate the cornea. That is what the Thill and his assistant study [7] seems to demonstrate with the highlighting of a new population of repairing stem cells located inside the adult human corneal stroma. These cells might evolve toward the monocyte-macrophage specie or toward the ti broblast specie (keratocytes). 

The construction of the eye is completely different. The outer layer of this mucosa consists of a tiny tear layer of lipids and water which covers a superficial epithelium closed by double layer lipid membranes of 30-70 nm size interconnected by tight jnnctions. Three to seven layers of epithelial cells cover the stromal structures of conjunctiva or cornea. The conjnnctival surface has interposed cells secreting small amonnts of mucin, the so-called goblet cells, which are typically missing within the corneal epithelinm. The regeneration of epithelial structnres is dne to the limbal stem cells located deep in the Vogt s crypts, for the cornea. 

Krishna N, Brow F. Polyvinyl alcohol as an ophthalmic vehicle effect on regeneration of corneal epithehum. Am J Ophthalmol 1964 57 99-106. 

Bowman s layer is a thin homogeneous sheet of acellular randomly arranged collagen fibers lying between the epithelial basement membrane and the stroma. Bowman s layer is relatively tough and provides substantial resistance to corneal injury or infection. Because it cannot regenerate, scarring results when it is disrupted. 

Recent research has demonstrated that adult human corneal endothelial cells can be grown in culture and transplanted into recipient corneas. Because human endothelial cells retain the capacity to proliferate, growth factors and inhibitors are under study as a potential method for regenerating damaged endothelial cells and increasing cell density to restore endothelial layer function. 

Acute hydrops secondary to keratoconus tends to be self-limiting in approximately 8 to 10 weeks when the corneal endothelial cells regenerate across the rupture in... 

In 1976, I received a telephone call from a former clinical fellow at the Retinal Foundation, David Miller, who was now the Head of Ophthalmology at Beth Israel Hospital in Boston. He remembered that in the late 1960s, we tested Healon in eye surgery during corneal transplantation to protect the thin layer of endothelial cells on the inside of the cornea from mechanical damage. These cells die when mechanically injured and do not regenerate in adults. Their function is to pump water... 

Summary Stimulating effects of some silatranes and silocanes leadmg to activation of corneal reparative regeneration afler mechanical trauma, protein-synthesizing components, and cicatrizing of experimental bums of rats were studied. Several aspects of the mechanisms of these stimulating effects are discussed. 

Porcine corneal models have been used to develop in vitro/ex vivo models able to detect recovery of ocular injury. In preliminary studies porcine corneas cultured for at least 120 h showed regeneration of the damaged stratified epithelium by treatment with 3 % SLS and Ethanol [84], The model was further optimized and developed towards an ocular irritancy assay based on porcine corneas with reversibility as an endpoint, called the Porcine Corneal Ocular Reversibility Assay (PorCORA) [85]. The assay uses an air-interface porcine corneal culture system, and is maintained in culture for 21 days, similar to the in vivo observation period, to determine reversibility of corneal injury as measured by sodium fluorescein and to detect potential compromised epithelial barrier function. 

The effects of liquid sulphur mustard upon the eye mirror those upon the skin. Early corneal changes, including pyknosis in the epithelium and substantia propria, leading to corneal necrosis by 12 h were reported. Regeneration of... 

Stimulate appetite in AIDS Lambert-Eaton myasthenic syndrome and Charcot-Marie tooth disease Trypanosoma brucei gambiense (sleeping sickness) Pneumocystis carinii pneumonia in AIDS organ transplant recipients Corneal epithelial regeneration and healing Anemia associated with end-stage renal disease Anemia associated with end-stage renal disease Primary pulmonary hypertension Acute lymphocytic leukemia... 

On the eleventh day after operation, in the case of the control animals a complete epithelization of the whole traumatized corneal surface took place. However, the thickness of the regenerating bed was not uniform over its entire surface. Thickened sites with epithelium growing deep down alternated with thin sites poorly bonded to subjacent connective tissue of the cornea itself. On the periphery of the cornea itself, the cells were more differentiated fascicles of friable collagenic fibers were located at random, inter-fascicle glottis was poorly expressed, and a small amount of chemosis of tissue and cell swelling was observed. 

Chitosan scaffolds may find application in regeneration of skin tissue, liver tissue, bone and cartilage tissue, cardiac tissue, corneal tissue, and vascular tissue to mention a few [73]. A brief account of its application in various branches of tissue engineering is described in this section. 

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