Recently Identified Forms of Epidermolysis Bullosa

Epidermolysis bullosa (EB) comprises a collection of clinically diverse inherited blistering diseases that affect the skin and, in some subtypes, mucous membranes and other organs. Currently classified into four main subtypes (EB simplex, junctional EB, dystrophic EB, and Kindler syndrome, mainly based on the level of skin cleavage), the spectrum of EB extends to more than 30 clinical subtypes with pathogenic mutations in at least 18 distinct genes. This review focuses on three recent additions to variants of EB: all are autosomal recessive, and result from mutations in either DST-e (coding for epidermal dystonin, also known as the 230 kDa bullous pemphigoid antigen, BP230), EXPH5 (coding for exophilin-5, also known as Slac2-b), or ITGA3 (coding for the integrin alpha-3 subunit). Each of these new forms of EB is reviewed with respect to the initial gene discovery, clinical features, the current mutation database, and skin pathology. Awareness of these recently described forms of EB is helpful in the clinical evaluation of patients with EB and in defining genotype-phenotype correlation for inherited blistering skin diseases.

Effect of Amniotic Membrane on Epithelial Thickness and Formation of Hemidesmosomes after Corneal Stromal Wound

PURPOSE: To investigate the effects of an amniotic membrane patch on corneal epithelial thickness and formation of hemidesmosomes during corneal stromal wound healing. METHODS: A stromal wound 9 mm in diameter and 130 microm in depth was created on rabbit cornea using a microkeratome. The changes in corneal epithelial thickness and hemidesmosome formations were compared between the amniotic membrane, contact lens, and control groups. Changes in the corneal epithelium were examined using H&E staining and hemidesmosome formation was examined using an electron microscope at 2 and 4 weeks after flap removal. RESULTS: Two weeks after treatment, the corneal epithelial thickness was 95.3 +/- 6.3 microm in the amniotic membrane group being significantly thicker than 76.4 +/- 5.1 microm in the contact lens group and 68.3 +/- 6.1 microm in the control group. Furthermore, more hemidesmosome formations were observed in the amniotic membrane group compared to the other 2 groups. However, there were no significant differences in corneal epithelial thickness or hemidesmosome formation among the 3 groups at week 4. CONCLUSIONS: The amniotic membrane group showed a thicker corneal epithelium and more hemidesmosome formation than the other 2 groups 2 weeks after flap removal. Thus, the use of an amniotic membrane patch appears to be effective in the early stages of corneal stromal wound healing.

Formation of basement membrane and stratification of Rabbit oral keratinocytes cultured on human acellular dermal matrix

Adhesion Complex in Cultivated Limbal Epithelium on Amniotic Membrane after Transplantation into Chemical Burn Model

PURPOSE: To investigate adhesion complex formation in cultivated human limbal epithelium after transplantation into the chemical burn model. METHODS: human limbal epithelial cells were cultured on amniotic membrane that had not undergone dispase treatment. Laminin V was evaluated using immunohistochemistry. The adhesion complex was examined by electron microscopy. Cultured epithelium was transplanted into limbal deficient rabbits induced by chemical burn and mechanical limbal removal. The transplanted rabbits and the controls with mechanical wounding were sacrificed at 1, 2, 3, and 4 weeks. The adhesion complex was examined by electron microscopy. RESULTS: Linear staining was observed against laminin V at 4-week culture but matured adhesion complex was not found. Graft failure developed in 3 rabbits (25%) after transplantation. Morphologically identifiable hemidesmosomes appeared at 1 week and matured adhesion complex with continuous basement membrane was found at 3 weeks. The mean numbers of hemidesmosomes/2.25 micro meter were 2.3 +/- 0.9, 2.5 +/- 0.5, 5.2 +/- 1.0, and 4.0 +/- 0.9 at 1, 2, 3, and 4 weeks, respectively. The adhesion assembly nearly recovered to the level of that in the human cornea (3.7 +/- 60.11) at 3 weeks. CONCLUSIONS: Adhesion complex of cultivated limbal epithelium did not developed in vitro, but the assembly was almost completed at 3 weeks after transplantation in vivo.