Collagenase Secretion Research Articles

Integration of the NF-κB and mitogen-activated protein kinase/AP-1 pathways at the Collagenase-1 promoter: Divergence of IL-1 and TNF-dependent signal transduction in rabbit primary synovial fibroblasts

Collagenase-1 (MMP-1) is a protease that is expressed by stromal cells and that is involved in remodeling of the extracellular matrix. IL-1 and TNF-α enhance collagenase secretion by stromal cells, and chronic exposure of cells to these cytokines can contribute to connective tissue disease. In this study, we show that the NF-κB pathway is required for activation of collagenase-1 transcription in rabbit primary synovial fibroblasts (RSF). Although both IL-1 and TNF activate NF-κB in these cells, only IL-1 induces collagenase-1 transcription. We have reported previously that NF-κB and AP-1 cooperate to mediate IL-1-induced MMP-1 transcription. Here, we show that IL-1 is superior to TNF at inducing c-Jun synthesis, phosphorylation and binding activity in RSF. Similarly, IL-1 is more effective at activating the mitogen-activated protein kinases (MAPK), including the extracellular signal-regulated kinases (ERK), which are required for IL-1-induced MMP-1 transcription. Thus stimulation of the ERK and AP-1 pathways is an essential component of MMP-1 transcriptional activation, which is deficient in TNF-treated cells. These studies demonstrate cooperation between the MAPK and NF-κB signaling pathways for IL-1-dependent collagenase-1 transcription, and they define a dichotomy of IL-1- and TNF-elicited signaling that is relevant to cytokine-mediated connective tissue disease.

Expression of osteopontin messenger RNA and protein in rheumatoid arthritis: effects of osteopontin on the release of collagenase 1 from articular chondrocytes and synovial fibroblasts.

Osteopontin (OPN) is an extracellular matrix protein that has been implicated in the interactions between tumor cells and host matrix, including those involved in invasion and spread of tumor cells. Because joint destruction in rheumatoid arthritis (RA) is mediated by the invasive growth of synovial tissue through its attachment to cartilage, we examined the expression of OPN in the synovia of patients with RA and the effect of OPN on the production of collagenase 1 in rheumatoid synovial fibroblasts and articular chondrocytes. The expression of OPN messenger RNA (mRNA) and protein in synovia from 10 RA patients was examined by in situ hybridization and immunohistochemistry. Synovial fibroblasts from RA patients and articular chondrocytes from patients without joint disease were cultured in the presence of various concentrations of OPN, and levels of collagenase 1 in the culture supernatants were measured by enzyme-linked immunosorbent assay. The expression of OPN mRNA and protein was observed in 9 of 10 specimens obtained from patients with RA. OPN was expressed in the synovial lining and sublining layer and at the interface of cartilage and invading synovium. Double labeling revealed that the majority of OPN-expressing cells were positive for the fibroblast-specific enzyme prolyl 4-hydroxylase and negative for the macrophage marker CD68, while only a few, single OPN-expressing cells were positive for CD68 at sites of synovial invasion into cartilage. OPN staining was not observed in lymphocytic infiltrates or leukocyte common antigen (CD45)-positive cells. Three of 3 cultures of human articular chondrocytes secreted detectable basal amounts of collagenase, with a dose-dependent increase upon OPN stimulation, while synovial fibroblast cultures produced much lower levels of collagenase, with only 2 of 4 fibroblast cultures responding in a dose-dependent manner. These findings suggest that OPN produced by synovial fibroblasts in the synovial lining layer and at sites of cartilage invasion not only mediates attachment of these cells to cartilage, but also contributes to matrix degradation in RA by stimulating the secretion of collagenase 1 in articular chondrocytes.

Expression of osteopontin messenger RNA and protein in rheumatoid arthritis: Effects of osteopontin on the release of collagenase 1 from articular chondrocytes and synovial fibroblasts

Objective Osteopontin (OPN) is an extracellular matrix protein that has been implicated in the interactions between tumor cells and host matrix, including those involved in invasion and spread of tumor cells. Because joint destruction in rheumatoid arthritis (RA) is mediated by the invasive growth of synovial tissue through its attachment to cartilage, we examined the expression of OPN in the synovia of patients with RA and the effect of OPN on the production of collagenase 1 in rheumatoid synovial fibroblasts and articular chondrocytes. Methods The expression of OPN messenger RNA (mRNA) and protein in synovia from 10 RA patients was examined by in situ hybridization and immunohistochemistry. Synovial fibroblasts from RA patients and articular chondrocytes from patients without joint disease were cultured in the presence of various concentrations of OPN, and levels of collagenase 1 in the culture supernatants were measured by enzyme-linked immunosorbent assay. Results The expression of OPN mRNA and protein was observed in 9 of 10 specimens obtained from patients with RA. OPN was expressed in the synovial lining and sublining layer and at the interface of cartilage and invading synovium. Double labeling revealed that the majority of OPN-expressing cells were positive for the fibroblast-specific enzyme prolyl 4-hydroxylase and negative for the macrophage marker CD68, while only a few, single OPN-expressing cells were positive for CD68 at sites of synovial invasion into cartilage. OPN staining was not observed in lymphocytic infiltrates or leukocyte common antigen (CD45)–positive cells. Three of 3 cultures of human articular chondrocytes secreted detectable basal amounts of collagenase, with a dose-dependent increase upon OPN stimulation, while synovial fibroblast cultures produced much lower levels of collagenase, with only 2 of 4 fibroblast cultures responding in a dose-dependent manner. Conclusion These findings suggest that OPN produced by synovial fibroblasts in the synovial lining layer and at sites of cartilage invasion not only mediates attachment of these cells to cartilage, but also contributes to matrix degradation in RA by stimulating the secretion of collagenase 1 in articular chondrocytes.

TRANSFORMING GROWTH FACTOR-β1 BLOCKS THE RELEASE OF COLLAGEN FRAGMENTS FROM BOVINE NASAL CARTILAGE STIMULATED BY ONCOSTATIN M IN COMBINATION WITH IL-1α

Oncostatin M in combination with interleukin-1 (IL-1) induced a rapid and reproducible release of collagen from bovine nasal cartilage in culture. This release was accompanied by a high collagenolytic activity and low or absent tissue inhibitor of metalloproteinase-1 activity in the culture medium. Transforming growth factor-β1 was able to block this release of collagen from the tissue, and reduce the expression and secretion of collagenases whilst maintaining TIMP-1 levels from bovine nasal chondrocytes. This study shows for the first time that TGF-β1 can protect cartilage collagen from destruction.

Cellular responses to whitlockite.

Whitlockite crystals have been observed in both degenerating and normal articular cartilages. To determine their potential for inducing cartilage degeneration, we studied their ability to induce mitogenesis and synthesis and secretion of metalloproteases in vitro. Whitlockite crystals were found to stimulate cell proliferation and to stimulate synthesis and secretion of stromelysin and collagenase. However, they were less stimulatory than crystals that contained calcium (Ca) and phosphate without magnesium substitution for Ca. Whitlockite crystals elicit biologic cellular responses that suggest potential pathogenicity in arthritis, but are less potent than Ca phosphate crystals without magnesium.

Expression of multiple matrix metalloproteinases and urokinase type plasminogen activator in cultured Kaposi sarcoma cells

Kaposi's sarcoma (KS) cells are considered to be of endothelial origin. KS lesions are characterized by hyperproliferation and an invasive phenotype. We have determined that KS cell cultures constitutively secrete multiple forms of several matrix metalloproteinases (MMPs) and an altered form of urokinase plasminogen activator (uPA) by zymogram and Western analysis of the culture media. MMPs are a family of secreted endoproteinases which degrade components of the extracellular matrix. Their enhanced expression and activity are strongly correlated with cellular processes involving tissue remodeling and invasion. The KS cells secrete increased levels of gelatinase A and B and a high molecular weight uPA in vitro when compared with non-KS endothelial or epithelial cells. Multiple forms of gelatinases A and B were observed on gelatin zymograms. Caseinolytic bands observed were confirmed by Western blot analysis to be due to stromelysin activity, whereas matrilysin was not detected by casein zymography. Western blot analysis also detected secretion of interstitial collagenase and high molecular weight uPA. Gelatinolytic activity with the mobility of gelatinase B was detected on gelatin zymograms, but not by Western analysis. This unusual constitutive expression pattern of MMPs and uPA by KS cells in vitro is characterized by elevated levels of gelatinase A, gelatinase B, interstitial collagenase, stromelysin and a high molecular weight form of uPA, and the lack of expression of matrilysin. These secreted MMPs, taken together, are capable of digesting a broad range of components of the extracellular matrix. This unusual pattern is likely to contribute to the characteristic hyperproliferative and invasive phenotype of KS lesions.

Soluble Arg-Gly-Asp peptides reduce collagen accumulation in cultured rat hepatic stellate cells.

Hepatic stellate cells play a central role in the pathogenesis of liver fibrosis, both via production of extracellular matrix proteins and through secretion of matrix metalloproteinases. In this study, effects of soluble cell adhesion peptides on collagen type I accumulation and on expression of matrix metalloproteinases were analyzed. First, we revealed the expression of alpha5-integrin on hepatic stellate cells by immunostaining. Treatment with 100 microg/ml of soluble Arg-Gly-Asp (RGD) peptides was found to reduce accumulation of type I collagen without any effects on its transcriptional level in rat hepatic stellate cells, whereas a control peptide Gly-Arg-Gly-Glu-Ser (GRGES) had no such effect. Soluble RGD peptides also increased the secretion of collagenase by stellate cells. These data suggested that reduced accumulation of type I collagen caused by the RGD peptide ligation to integrins on hepatic stellate cells was partly due to stimulated expression of collagenase by stellate cells.

Fibroblast-migration in a wound model of ascorbic acid-supplemented three-dimensional culture system: the effects of cytokines and malotilate, a new wound healing stimulant, on cell-migration

To assess the migratory response of fibroblasts in vitro, normal human dermal fibroblasts (NHDF) were cultured in the presence of l-ascorbic acid 2-phosphate to induce a multilayered structure. Round wounds were made by punching, and the migratory response was evaluated by counting the number of migrating cells in the wounded areas. Collagenase activity in the culture-medium was then measured. When the wound model was treated with bFGF, IL-1 α or PDGF, the migratory response was facilitated with increased collagenase secretion. In contrast, treatment with TGF- β reduced the migratory response and collagenase secretion. Since the multilayered structure is rich in collagenous matrix, degradation of the matrix by secreted collagenase is probably necessary for the cells to migrate into the wounded areas. Furthermore, malotilate, which is now under development as an agent for wound therapy, facilitated the migratory response of NHDF with increased collagenase secretion in this wound model, suggesting that the wound healing effect of malotilate is in part attributable to stimulated migration of fibroblasts to wounded areas subsequent to extracellular matrix-degradation.

Cytokine sensitivity of metastatic human melanoma cell lines-- simultaneous inhibition of proliferation and enhancement of gelatinase activity.

The effect of a panel of cytokines on the proliferation and type IV collagenase production was studied in four melanoma cell lines of different origin, tumorigenicity and metastatic capacity. TGF-b, TNF-a and to a lesser extent, IL-1a exhibited antiproliferative effect on the cell lines, with some lines showing varying degree of resistance. The sensitivity did not correlate directly with the origin or the biological behavior of the tumor lines, suggesting that cytokine resistance of advanced stage melanoma cells may be relative. IL-2, IL-10 and IL-12 displayed little or no effect on proliferation. The effect of cytokines on metalloproteinase production showed a cell line dependent pattern. Interestingly, those cytokines that exhibited the most pronounced antiproliferative activity, also proved most effective in stimulating collagenase secretion, often simultaneously, in the same line. The results indicate that pleiotropic cytokines can have positive and negative effects simultaneously on various steps of tumor progression.

Vascular endothelial groth factor induces tissue factor and matrix metalloproteinase production in endothelial cells: Conversion of prothrombin to thrombin results in progelatininase a activation and cell proliferation

Production of vascular endothelial growth factor (VEGF) by cancer cells at invasive and metastatic sites is an important aspect of tumor angiogenesis. Although known primarily as a mitogen and a vascular permeability factor (VPF) for endothelial cells, VEGF/VPF has been proposed to induce the expression of procoagulant factors in endothelial cells. In this study, we have explored the ramifications of VEGF induction of tissue factor (TF) in human umbilical vein endothelial cells (HUVECs) and subsequent activation of progelatinase A. Within 3 hr of incubation with VEGF/VPF, endothelial cells accelerate TF generation as measured using chromogenic substrate assays for coagulation factors Xa and thrombin. Incubation of VEGF/VPF-pre-treated cells with prothrombin and factors X, Va, and VIIa at 37°C and subsequent generation of thrombin resulted in activation of secreted endothelial progelatinase A as demonstrated by gelatin zymography. Anti-thrombin III or antibodies to TF inhibited thrombin generation and progelatinase A activation. VEGF/VPF also directly increased HUVEC secretion of interstitial collagenase, tissue inhibitor of metalloproteinases (TIMP-1) and, to a lesser extent, gelatinase A. The effect of thrombin on endothelial proliferation in serum-free media was examined. Thrombin was a growth factor for HUVECs at a lower dose than that required for progelatinase A activation. Whereas TIMP-2 abrogated thrombin-induced progelatinase A activation, it had no significant effect on thrombin-induced endothelial cell growth. We propose that an early step in tumor angiogenesis involves VEGF-induced thrombin generation and increased MMP production with subsequent activation of endothelial progelatinase A and degradation of the underlying basement membrane. Int. J. Cancer 75:780–786, 1998. Published 1998 Wiley-Liss, Inc.1 This article is a US Government work and, as such, is in the public domain in the United States of America.

Vascular endothelial growth factor induces tissue factor and matrix metalloproteinase production in endothelial cells: conversion of prothrombin to thrombin results in progelatinase A activation and cell proliferation.

Production of vascular endothelial growth factor (VEGF) by cancer cells at invasive and metastatic sites is an important aspect of tumor angiogenesis. Although known primarily as a mitogen and a vascular permeability factor (VPF) for endothelial cells, VEGF/VPF has been proposed to induce the expression of procoagulant factors in endothelial cells. In this study, we have explored the ramifications of VEGF induction of tissue factor (TF) in human umbilical vein endothelial cells (HUVECs) and subsequent activation of progelatinase A. Within 3 hr of incubation with VEGF/VPF, endothelial cells accelerate TF generation as measured using chromogenic substrate assays for coagulation factors Xa and thrombin. Incubation of VEGF/VPF-pre-treated cells with prothrombin and factors X, Va, and VIIa at 37 degrees C and subsequent generation of thrombin resulted in activation of secreted endothelial progelatinase A as demonstrated by gelatin zymography. Anti-thrombin III or antibodies to TF inhibited thrombin generation and progelatinase A activation. VEGF/VPF also directly increased HUVEC secretion of interstitial collagenase, tissue inhibitor of metalloproteinases (TIMP-1) and, to a lesser extent, gelatinase A. The effect of thrombin on endothelial proliferation in serum-free media was examined. Thrombin was a growth factor for HUVECs at a lower dose than that required for progelatinase A activation. Whereas TIMP-2 abrogated thrombin-induced progelatinase A activation, it had no significant effect on thrombin-induced endothelial cell growth. We propose that an early step in tumor angiogenesis involves VEGF-induced thrombin generation and increased MMP production with subsequent activation of endothelial progelatinase A and degradation of the underlying basement membrane.

Regulation of keratinocyte motility and collagenase secretion by mitogen-activated protein kinase

Regulation of keratinocyte motility and collagenase secretion by mitogen-activated protein kinase

Ginseng intestinal bacterial metabolite IH901 as a new anti-metastatic agent

Anti-metastatic activities of IH901, an intestinal bacterial metabolic derivative formed from Ginseng protopanaxadiol saponins, was determinedin vitro andin vivo. Underin vitro conditions, IH901 inhibited the migration of bovine aortic endothelial cells 25 times stronger than suramin and suppressed the invasion of HT1080 human fibrosarcoma cells into reconstituted basement membrane components of Matrigel 1000 times stronger than RGDS peptide. IH901 also showed inhibitory effect on type-IV collagenase secretion from HT1080 cells and platelet aggregation. When the anti-metastatic activity of IH901 was evaluated in comparison with that of 5-FU using a spontaneous lung metastatic model of Lewis lung carcinoma, the administration of IH901 (10 mg/kg p. o.) to tumor-bearing mice led to a significant decrease in lung metastasis (43% of untreated control), which was slightly more effective than that obtained with 5-FU (56% of control). Thus, IH901 seems to exhibit its anti-metastatic activity partly through the inhibition of tumor invasion which results from the blockade of type IV collagenase secretion and also through anti-platelet and anti-angiogenic activities.

Corticosteroids repress the interleukin 1 beta-induced secretion of collagenase in human intestinal smooth muscle cells

BACKGROUND & AIMS: The cytokine interleukin (IL)-1 beta induces collagenase expression and inhibits collagen expression in human intestinal smooth muscle (HISM) cells. Corticosteroids cause transrepression of certain genes, including the collagenase gene. The aim of this study was to determine if corticosteroids repress the induction of collagenase expression and the inhibition of collagen secretion by IL-1 beta in HISM cells. METHODS: HISM cells were exposed to IL-1 beta (1-100 pmol/L) for 24 hours in the presence or absence of dexamethasone (10(-6) mol/L). Collagenase messenger RNA (mRNA) levels were determined by ribonuclease protection assay. Collagenase and tissue inhibitor of metalloproteinase protein secretion were determined by enzyme-linked immunosorbent assay of culture medium. Procollagen and collagen secretion were determined by polyacrylamide slab gel analysis of radiolabeled proteins in culture medium. RESULTS: A 30-fold induction of collagenase mRNA and collagenase protein secretion by IL-1 beta was completely abrogated by dexamethasone. Dexamethasone at 10(-6) mol/L also reduced basal levels of collagenase mRNA by 50% and blocked the IL-1 beta-induced inhibition of collagen secretion. CONCLUSIONS: Corticosteroids repress the collagenolytic action of IL-1 beta on HISM cells in vitro and therefore should promote healing in the inflamed intestine. (Gastroenterology 1997 Dec;113(6):1924-9)

Effect of curcumin and capsaicin on arachidonic acid metabolism and lysosomal enzyme secretion by rat peritoneal macrophages.

The inflammatory mediators secreted by macrophages play an important role in autoimmune diseases. Spice components, such as curcumin from turmeric and capsaicin from red pepper, are shown to exhibit antiinflammatory properties. The influence of these spice components on arachidonic acid metabolism and secretion of lysosomal enzymes by macrophages was investigated. Rat peritoneal macrophages preincubated with 10 microM curcumin or capsaicin for 1 h inhibited the incorporation of arachidonic acid into membrane lipids by 82 and 76%: prostaglandin E2 by 45 and 48%; leukotriene B4 by 61 and 46%, and leukotriene C4 by 34 and 48%, respectively, but did not affect the release of arachidonic acid from macrophages stimulated by phorbol myristate acetate. However, the secretion of 6-keto PG F1 alpha was enhanced by 40 and 29% from macrophages preincubated with 10 microM curcumin or capsaicin, respectively, as compared to those produced by control cells. Curcumin and capsaicin also inhibited the secretion of collagenase, elastase, and hyaluronidase to the maximum extent of 57, 61, 66%, and 46, 69, 67%, respectively. These results demonstrated that curcumin and capsaicin can control the release of inflammatory mediators such as eicosanoids and hydrolytic enzymes secreted by macrophages and thereby may exhibit antiinflammatory properties.

Modulation of intracellular calcium levels inhibits secretion of collagenase 1 by migrating keratinocytes.

Calcium concentration influences keratinocyte differentiation, and, following injury, keratinocytes move through an environment of changing calcium levels. Because these migrating cells in wounds invariably express collagenase 1, we assessed if modulation of calcium levels regulates collagenase 1 production by primary human keratinocytes. Accurately reflecting the confined spatial pattern of enzyme production seen in vivo, collagenase 1 mRNA was expressed only by keratinocytes migrating from foci of differentiated cells. Treatment with calcium ionophores A23187 or thapsigargin markedly inhibited the basal and phorbol 12-myristate 13-acetate-(PMA) stimulated accumulation of keratinocyte collagenase 1 in the medium but did not affect collagenase 1 production by control or PMA-treated fibroblasts. A23187-mediated inhibition of collagenase 1 protein was not associated with a decrease in mRNA levels but rather was controlled by a selective and reversible block of enzyme secretion. This block in secretion was likely not due to altered protein folding as the proenzyme within A23187-treated cells remained capable of autolytic activation upon treatment with p-aminophenylmercuric acetate. In contrast, 92-kDa gelatinase mRNA and secreted protein levels were coordinately reduced by A23187. Keratin 14 expression, a basal keratinocyte marker, was reduced with PMA treatment, but A23187 did not affect keratin 14 expression. In human wounds, both basal and suprabasal keratinocytes at the migrating front of epidermis stained for keratin 14, but only the basal cells expressed collagenase 1. These data suggest that collagenase 1 production is not necessarily linked with expression of basal cell markers and that modulation of intracellular calcium levels can block secretion of collagenase 1 by keratinocytes which have moved away from the stratum basalis and from their natural substrate.

Increased expression of urokinase type plasminogen activator(u-PA), plasminogen activator inhibitor-1(PAI-1), and collagenases in Caco-2 cells infected by Salmonella typhimurium.

Salmonella penetrates the basement membrane of intestinal epithelial cells into deeper tissues, in which process extracellular matrix proteases should be required. Hypothesizing that the proteases might be provided by host cells, we investigated the changes of expression of urokinase type plasminogen activator(u-PA), plasminogen activator inhibitor-1(PAI-1), and collagenases in epithelial cells(Caco-2) infected with Salmonella typhimurium. The change of mRNA levels, amount of the enzyme secretion and functional activity were analyzed by Northern blot, ELISA, and Zymography. The mRNA level of u-PA was elevated by Salmonella infection itself without any exogenous transcription regulators. u-PA was actively secreted into the medium and was enzymatically active. The synthesis and secretion of PAI-1 was increased over time from 2 hrs post infection(pi) to 8 hrs pi. Zymographic assay revealed that the secretion of collagenases (type IV, type V and interstitial collagenase) were also increased. Taken together, S. typhimurium infection might induce accumulation of pericellular proteolytic activity and consequently degrade the extracellular matrix surrounding the infected cells. These in turn might enable Salmonella to invade into deeper tissues.

Substance P induces the secretion of gelatinase A from human synovial fibroblasts.

We investigated the secretion of the matrix metalloproteinases, interstitial collagenase (matrix metalloproteinase-1), gelatinase A (matrix metalloproteinase-2) and stromelysin-1 (matrix metalloproteinase-3) in human synovial fibroblasts after stimulation with the neuropeptide substance P. Human synovial fibroblasts were stimulated with substance P or interleukin-1 beta (IL-1 beta). In the cell culture media gelatinase A, interstitial collagenase and stromelysin-1 were identified and their activities towards different substrates were determined. Substance P in synovial fibroblasts induced an increase in the overall matrix metalloproteinase activity towards the dinitrophenyl-labelled peptide by 85%, against an increase of 124% after stimulation with IL-1 beta. In case of substance P stimulation, the increase in activity reflects a significantly enhanced secretion of gelatinase A, whereas no significant increase of stromelysin-1 and collagenase secretion could be observed. The matrix metalloproteinase pattern showing the highest gelatinase A secretion was obtained after stimulation with substance P. This pattern was very pronounced and differed very clearly from the pattern seen after IL-1 beta stimulation which caused a significant rise in collagenase and stromelysin-1 activity. We assume that distinct stimulation pathways are involved and that the neuropeptide (substance P), which is always present in the inflamed joint, plays its own and separate role in proliferative processes leading to the cartilage destruction.

Different Sensitivities of Neutrophil Responses to a Selective Protein Kinase C Inhibitor, Ro 31-8425; Redundancy in Signal Transduction

Previous studies implicating a role for protein kinase C (PKC) in mediating stimulation of cellular responses by physiological agonists have relied on use of non-specific inhibitors or direct stimulation of PKC by phorbol esters. However, much of this evidence is questionable. Here, we have investigated the effects of a potent and selective PKC inhibitor, Ro 31-8425, on three different responses of human neutrophils stimulated by either a physiological agonist, C5a, or a phorbol ester, PMA. The responses studied were superoxide generation, collagenase secretion and adhesion to endothelial cells. In each case, the PMA-stimulated response was more sensitive to inhibition than the C5a-stimulated response. Even the PMA-stimulated responses differed in their sensitivity to inhibition, with superoxide production being the most sensitive and adhesion the least sensitive. The different sensitivities of the PMA stimulated responses suggest that, although activation of PKC stimulates the responses, either different degrees of activation or different isozymes are required for the different responses. The lower sensitivity of the C5a-stimulated responses in each case suggests that PKC activation, if needed at all, is not rate limiting in these signal transduction pathways. These results emphasize the redundancy in intracellular signal transduction.

Phenytoin in the Treatment of Epidermolysis Bullosa

Objective: To review the efficacy of phenytoin in the treatment of epidermolysis bullosa (EB). Data Sources: English-language clinical study reports, abstracts, case reports, and review articles pertaining to the use of phenytoin in the treatment of EB (MEDLINE search, January 1973-August 1996). Data Extraction: Clinical study and case reports evaluating the effect of phenytoin in the treatment of EB were reviewed, and the methodology, results, and conclusions of the studies were evaluated. Because of the limited number of randomized, controlled study reports, all available case reports were reviewed, and information we considered pertinent was synthesized. Data Synthesis: Results of studies of EB suggest that the blister fluid and fibroblasts in patients with this disease produce an increased amount of collagenase, which is thought to induce blistering. Phenytoin inhibits collagenase synthesis and/or secretion and, therefore, is used to treat patients with EB. Data regarding the use of phenytoin in patients with EB, especially those with recessive dystrophic EB, revealed that phenytoin may reduce the number of blisters in these patients. Dosage recommendations and monitoring parameters are also discussed. Conclusions: More randomized, controlled trials are needed to determine the true efficacy of phenytoin in the treatment of EB. Although the only available report of a randomized, controlled trial reported a lack of phenytoin efficacy in patients with EB, it does not rule out the possibility of success in selected patients.