Human bullous pemphigoid (BP) is an immune-mediated blistering disease characterized by autoantibodies against BP antigens (230/180 kd), which are constitutive glycoproteins of hemidesmosomes found in basal keratinocytes. Blistering diseases similar to human BP have been reported in dogs. IgG deposits at the basement membrane zone (BMZ) are a common feature of canine BP. Although circulating anti-BMZ IgG autoantibodies have been demonstrated in some cases of canine BP, the specific skin protein targeted by these autoantibodies has not been identified. In this study, we characterized the antigenic target of the autoantibodies in the serum from a 3-year-old castrated male Pit Bull Terrier with BP. Direct immunofluorescence of the patient's skin demonstrated IgG deposits at the dermal-epidermal junction. Indirect immunofluorescence demonstrated autoantibodies in the patient's serum that stained the epidermal roof of salt-split canine skin and left the dermal floor unstained. These serum autoantibodies did not stain normal intact dog skin but labeled intact bovine tongue. Direct immunoelectron microscopy of the dog's skin revealed IgG deposits within the hemidesmosomes of the basal keratinocytes. Western immunoblotting experiments showed that canine keratinocytes express both the 230-kd and 180-kd bullous pemphigoid antigens, and the autoantibodies from the patient's serum recognized the 180-kd bullous pemphigoid antigen in proteins extracted from canine and human keratinocytes. Canine BP has many parallel features with human BP including similar immune deposition of IgG within hemidesmosomes and a hemidesmosome-associated 180-kd glycoprotein target for circulating autoantibodies.
En bloc autologous dermal fat grafting appears to be a safe technique that provides excellent cosmetic results for the correction of small to medium depressed scars of the forehead.
HSS appears to be a safe, well-tolerated biological dressing with equivalent comorbid factors to secondary intention healing. HSS, however, seems to produce a more pliable and less vascular scar than those developed through healing by secondary intention. HSS also appears to produce more satisfactory cosmetic results when compared to secondary intention healing.
Serine protease inhibitors have important regulatory roles in angiogenesis, intravascular fibrinolysis, wound healing, and cell migration. In this study, the extracellular matrix secreted by cultured human keratinocytes, foreskin fibroblasts, and SV-40-transformed human skin fibroblasts was analyzed for serine protease inhibitors by substrate reverse zymography. We found that the extracellular matrix deposited by these cells contained three inhibitors (M(r) 33,000, 31,000, and 27,000). These inhibitors protected the degradation of gelatin by trypsin and elastase, and of casein by plasmin. In contrast, the gelatinolytic activities of thermolysin and papain were not inhibited. Compared to untreated cells, cells treated with phorbol 12-myristate 13-acetate showed a two- to 10-fold increase in the expression of these inhibitors. Cycloheximide and actinomycin D decreased the cellular expression of these inhibitors, suggesting the involvement of de novo protein and mRNA synthesis. Antitrypsin activity of these inhibitors was resistant to heat and sodium dodecylsulfate, but was lost after reduction of disulfide bonds. The inhibitors bound specifically to trypsin and could be eluted from a trypsin column in active form. Collectively, these data suggest that the extracellular matrix deposited by keratinocytes and dermal fibroblasts contains active serine protease inhibitors.
Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) stimulate keratinocyte migration on collagen by up-regulating the alpha 2 subunit of the collagen integrin, alpha 2 beta 1. Interleukin-1 (IL-1) is an autocrine factor, produced by keratinocytes themselves, that is modulated by ultraviolet light and increases the proliferative potential of keratinocytes in culture. The autocrine nature of keratinocyte-derived IL-1 alpha is emphasized by the fact that it induces the keratinocyte to synthesize IL-1 alpha and TGF-alpha, a cytokine known to induce keratinocyte motility. Further, topical application of IL-1 alpha has been shown to promote wound healing in animals. In this study, we used a well-defined keratinocyte migration assay to assess the effect of IL-1 alpha on keratinocyte motility and to examine whether the IL-1 alpha/TGF alpha pathway is involved. The addition of recombinant human IL-1 alpha to keratinocytes produced a statistically significant and concentration-dependent increase in migration on matrices of collagen types I and IV, but not on laminin. Maximal levels of keratinocyte migration obtained on these matrices with IL-1 alpha were comparable to those obtained with stimulation by EGF and TGF-alpha. The effects of TGF-alpha and IL-1 alpha on keratinocyte migration are additive; however, the maximal level of migration achieved by using IL-1 alpha and TGF-alpha in combination never exceeds the maximal level of migration found by using either cytokine alone. The time course of keratinocyte migration induced by IL-1 alpha is delayed (onset of migration 9-12 h after addition) as compared with that induced by TGF-alpha (onset of migration 6-9 h after addition) even if the cells are preincubated in IL-1 alpha. Flow cytometry analysis demonstrated no change in surface expression of integrin subunits, specifically that of integrin subunit alpha 2, previously shown to be up-regulated by EGF/TGF-alpha. These results suggest that IL-1 alpha stimulates keratinocyte migration on collagen via a mechanism distinct from that of EGF/TGF-alpha.
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