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PubMed2002

Sites of collagenase cleavage and denaturation of type II collagen in aging and osteoarthritic articular cartilage and their relationship to the distribution of matrix metalloproteinase 1 and matrix metalloproteinase 13.

OBJECTIVE: To determine the sites of cleavage and denaturation of type II collagen (CII) by collagenase(s) in healthy and osteoarthritic (OA) human articular cartilage and their relationship to the distribution of matrix metalloproteinase 1 (MMP-1) and MMP-13. METHODS: Single (per subject) full-depth specimens from femoral condylar cartilage were isolated from articulating surfaces at autopsy from 8 subjects without arthritis and during arthroplasty from 10 patients with OA. Fixed frozen sections of cartilage were examined by immunoperoxidase localization, using antibodies to the collagenase-generated cleavage site in CII, to an intrachain epitope recognized only in denatured CII, and to MMP-1 and MMP-13 (proenzyme, activated enzyme, or enzyme/inhibitor complex). RESULTS: Staining for collagen cleavage, denaturation, and both MMPs was weak to moderate and was frequently observed in pericellular sites in cartilage from younger, nonarthritic subjects. In specimens from older subjects, this staining was often more widespread and of greater intensity. Similar staining was usually, but not always, seen for all antibodies. In OA cartilage, staining was often stronger and more intense than that in normal cartilage from older subjects, and the distribution of staining was often similar for the different antibodies. Pericellular staining in the deep zone was frequently more pronounced in arthritic cartilage and extended to territorial and sometimes interterritorial sites. In very degenerate specimens, staining was distributed throughout most of the cartilage matrix. CONCLUSION: These observations provide evidence for the presence of limited cleavage and denaturation of CII restricted to mainly pericellular and superficial sites in cartilage from younger, healthy subjects, where MMP-1 and MMP-13 are also selectively localized. Collagen degradation is more extensive and often more pronounced in cartilage from older, nonarthritic subjects. Characteristic changes in early OA are similar to those seen with aging in cartilage from older, healthy subjects, with collagen damage and collagenases concentrated closer to the articular surface. There was usually a close correspondence between the cleavage and denaturation of CII and the sites at which these collagenases were detected, suggesting that both MMPs are involved in the physiology and pathology. There was no evidence that the damage to CII is ordinarily initiated in sites other than at and near the articular surface and around chondrocytes.

Adult↗

PubMedDate not supplied

Matrix metalloproteinase-9,-3 and tissue inhibitor of matrix metalloproteinase-1 in colorectal cancer: relationship to clinicopathological variables.

The balance between matrix metalloproteinases (MMPs) and their physiological tissue inhibitors of matrix metalloproteinases (TIMPs) is crucial in tumour invasion and progression. The aim of this study was to investigate the levels of MMP-9, MMP-3 and TIMP-1 in colorectal cancer (CRC) and to evaluate these proteinases and their inhibitor with respect to clinicopathological variables. Activities of pro- and active MMP-9 were measured in paired tumour and distant normal tissue specimens from 43 patients with CRC using gelatin zymography. ELISA was employed for the determination of MMP-9, MMP-3 and TIMP-1 protein expressions. The activity levels of pro- and active MMP-9 and protein expression levels of MMP-9, MMP-3 and TIMP-1 were higher in tumour tissues than in the corresponding normal tissues; the differences being significant for all (p < 0.05), except TIMP-1. Similarly, active MMP-9/proMMP-9 and the ratio of protein expression level of MMP-9-TIMP-1 were found to be significantly higher in tumour tissues ( p < 0.01). Among all the clinicopathological variables investigated, significant correlations were found between MMP-9 and presence of perineural invasion, MMP-3 and lymph node status, TIMP-1 and tumour differentiation, MMP-9/TIMP-1 ratio and histological types ( p < 0.05). In conclusion, MMP-3 was not as notably increased as MMP-9 in tumour tissues. However, different roles may be attributed to MMP-9 and MMP-3 in CRC development and progression. Additionally, assessment of TIMP-1 in relation to MMPs appeared to be crucial in CRC studies to provide a basis for the re-evaluation of the clinical usefulness of TIMP-1 in colorectal cancer.

Aged↗

PubMed2001

Overexpression of matrix metalloproteinases leads to lethality in transgenic Xenopus laevis: implications for tissue-dependent functions of matrix metalloproteinases during late embryonic development.

The extracellular matrix (ECM) functions as the structural support of cells and as a medium for cell-cell interactions. It is understood to play critical roles in development. ECM remodeling is mediated largely through the action of matrix metalloproteinases (MMPs), a family of Zn2+-dependent proteases capable of degrading various proteinaceous components of the ECM. MMPs are expressed in many developmental and pathologic processes. However, few studies have been carried out to investigate the function of MMPs during embryogenesis and postembryonic organogenesis. By using Xenopus development as a model system, we have previously shown that several MMP genes are expressed from neurulation to the completion of embryogenesis in distinct tissues/organs, suggesting that ECM remodeling during mid- to late embryogenesis occurs in an organ-specific manner. By using the recently developed transgenic technology for Xenopus laevis, we overexpressed Xenopus MMPs stromelysin-3 (ST3) and collagenase-4 (Col4) under the control of a ubiquitous promoter and observed that embryos with overexpressed ST3 or Col4, but not the control green fluorescent protein (GFP), died in a dose-dependent manner during late embryogenesis. The specificity of this embryonic lethal phenotype was confirmed by the failure of a catalytically inactive mutant of ST3 to affect development. Finally, overexpression of a mammalian membrane type-MMP also led to late embryonic lethality in Xenopus embryos, suggesting that membrane type-MMPs have functions in vivo for ECM remodeling, in addition to being activators of other pro-MMPs. These data together with the developmental expression of several MMPs during Xenopus development, suggest that MMPs play important roles during mid- to late embryogenesis and that proper regulation of MMP genes is critical for tissue morphogenesis and organogenesis.

Animals↗

PubMed2002

Alterations in matrix metalloproteinase-9 levels and tissue inhibitor of matrix metalloproteinases-1 expression in a transforming growth factor-beta transgenic model of hydrocephalus.

The development of spontaneous hydrocephalus in mouse models resulting from the overexpression of transforming growth factor-beta (TGFbeta-1) has been previously described, although the mechanism by which this occurs remains obscure. It has been previously demonstrated that increased expression of TGFbeta has consequences for the levels of matrix metalloproteinases (MMPs) and their specific inhibitors (tissue inhibitors of MMPs, or TIMPs). These remodeling proteins play an important role in extracellular matrix (ECM) maintenance through degradation and deposition of ECM components. The present study investigated the relationship between elevated levels of TGFbeta-1, the ECM modulators TIMP-1 and MMP-9, and development of hydrocephalus in the neonatal mouse. In newborn pups, TIMP-1 mRNA levels were equal between animals expressing the TGFbeta-1 transgene and littermates without the transgene. However, immunohistochemistry of littermate pups shows that the distribution of TIMP-1 was changed from homogeneous with large punctate concentrations of signal to uniform, dense staining in hydrocephalic animals carrying the TGFbeta-1 transgene. The mRNA levels of MMP-9 were decreased in the transgenic animals, as were the activity levels MMP-9. These results suggest that the remodeling protein MMP-9 and its specific inhibitor, TIMP-1, may contribute to the spontaneous development of hydrocephalus in this transgenic model by altering the ECM environment.

Actins↗

PubMed2006

Accelerated repair of cortical bone defects using a synthetic extracellular matrix to deliver human demineralized bone matrix.

Injectable hydrogel and porous sponge formulations of Carbylan-GSX, a crosslinked synthetic extracellular matrix (ECM), were used to deliver human demineralized bone matrix (DBM) in a rat femoral defect model. A cortical, full-thickness 5-mm defect was created in two femurs of each rat. Six rats were assigned to each of five experimental groups (thus, 12 defects per group). The defects were either untreated or filled with Carbylan-GSX hydrogel or sponges with or without 20% (w/v) DBM. Radiographs were obtained on day 1 and at weeks 2, 4, 6, and 8 postsurgery of each femur. Animals were sacrificed at week 8 postsurgery and each femur was fixed, embedded, sectioned, and processed for Masson's Trichrome staining. The bone defects were measured from radiographs and the fraction of bone healing was calculated. The average fractions of bone healing for each group were statistically different among all groups, and all treatment groups were significantly better than the control group. The Carbylan-GSX sponge with DBM was superior to the sponge without DBM and to the hydrogel with DBM. Histology showed that defects treated with the Carbylan-GSX sponge plus DBM were completely filled with newly generated bone tissue with a thickness comparable to native bone. Carbylan-GSX sponge was an optimal delivery vehicle for human DBM to accelerate bone healing.

Animals↗

PubMed2001

Systematic separation and purification of elastase, gelatinase (matrix metalloproteinase 9), and collagenase (matrix metalloproteinase 8) from polymorphonuclear leukocytes in dialyzers previously used by patients with renal failure.

We developed a simple and effective method for the systematic separation and purification of human polymorphonuclear leukocyte (PMN) proteinases, elastase, gelatinase (matrix metalloproteinase 9, type IV collagenase), and collagenase (matrix metalloproteinase 8), derived from the extracts of hollow fiber dialyzers that had been utilized in the treatment of patients with renal failure. The fraction containing elastase was grossly separated from that containing gelatinase and collagenase by heparin-Sepharose chromatography and purified in an aprotinin column. The remaining two enzymes were then separated using the gelatin-Sepharose column after gel chromatography following ammonium sulfate precipitation. Gelatinase and collagenase were further purified by gelatin-Sepharose chromatography as a latent form and by collagen-Sepharose chromatography as an activated form. This novel method offers procedural advantages over existing methods that separate PMNs from the whole blood of volunteers for experimental research purposes.

Animals↗

PubMed1999

Expression of membrane type 1 matrix metalloproteinase, matrix metalloproteinase 2 and tissue inhibitor of metalloproteinase 2 in human cartilaginous tumors with special emphasis on mesenchymal and dedifferentiated chondrosarcoma.

Membrane type 1 matrix metalloproteinase (MT1-MMP) has been identified as an activator of the proenzyme of matrix metalloproteinase 2 (MMP-2: gelatinase A), and has also been shown to play a crucial role in tumor invasion by activating proMMP2 in both lung and gastric carcinoma. The tissue inhibitor of metalloproteinase 2 (TIMP-2) plus the MT1-MMP complex also plays an important role in the activation of proMMP-2. In this study, the expressions of MT1-MMP, MMP-2 and TIMP-2 were evaluated in 10 enchondromas, 34 conventional chondrosarcomas, 5 clear-cell chondrosarcomas, 7 mesenchymal chondrosarcomas and 8 dedifferentiated chondrosarcomas. The expressions were immunohistochemically visualized on paraffin sections and the levels of expression were assessed semiquantitatively. The extent of staining was assessed by the extent score in order to determine the overall level of expression. The extent scores of MT1-MMP, MMP-2 and TIMP-2 in grade 2 chondrosarcoma were significantly higher than those in either enchondroma or grade 1 chondrosarcoma (P < 0.05). In conventional chondrosarcoma, significant correlations were found between the extent scores of MT1-MMP and MMP-2 (P < 0.001), MT1-MMP and TIMP-2 (P < 0.01), and MMP-2 and TIMP-2 (P < 0.01). The undifferentiated small round tumor cells of mesenchymal chondrosarcoma showed lower positive rates and extent scores for MT1-MMP (2/7, 0.7 +/- 0.5) and MMP-2 (3/7, 0.7 +/- 0.4) than for cartilaginous components of mesenchymal chondrosarcoma [MT1-MMP (4/7, 1.3 +/- 0.5) and MMP-2 (7/7, 1.9 +/- 0.3)] or conventional chondrosarcoma. In dedifferentiated chondrosarcoma, the extent scores of MT1-MMP, MMP-2 and TIMP-2 in low-grade cartilaginous components were not significantly different from those in conventional chondrosarcoma; however, the high-grade anaplastic components showed high extent scores for MT1-MMP, MMP-2 and TIMP-2, compared with the low-grade cartilaginous components of dedifferentiated chondrosarcoma or conventional chondrosarcoma. According to our results, the expression of MT1-MMP as well as that of MMP-2 or TIMP-2 demonstrated a significant correlation with the tumor grade in human cartilaginous tumors. Furthermore, the expressions of MT1-MMP, MMP-2 and TIMP-2 were also found to play a crucial role in invasion in the high-grade components of dedifferentiated chondrosarcoma.

Bone Neoplasms↗

PubMed2006

Sendai virus infection up-regulates trypsin I and matrix metalloproteinase-9, triggering viral multiplication and matrix degradation in rat lungs and lung L2 cells.

To elucidate the virus-host cell interaction, we analyzed quantitatively the expression of various cellular proteases and tumor necrosis factor-alpha (TNF-alpha) after Sendai virus infection in rat lungs and lung L2 cells. After infection, TNF-alpha mRNA levels increased rapidly to a peak on day one, and then trypsin I and matrix metalloproteinase (MMP)-9, but not MMP-2, were significantly up-regulated with a peak on day 2 in vivo. These up-regulations were confirmed in L2 cells. Up-regulation of proMMP-9 and its active convertase trypsin I seems to synergistically enhance virus multiplication and the destruction of lung matrix, resulting in the progression of pneumonia.

Animals↗

PubMed2005

Effects of age, gender, ethnicity, diurnal variation and exercise on circulating levels of matrix metalloproteinases (MMP)-2 and -9, and their inhibitors, tissue inhibitors of matrix metalloproteinases (TIMP)-1 and -2.

BACKGROUND: Circulating metalloproteinases (MMP) and their inhibitors (TIMP) are indices of vascular and cardiac tissue matrix turnover. However, the temporal changes and relationship of these parameters to age, gender, ethnicity and exercise have been poorly defined. We therefore studied these aspects on plasma levels of MMP-2 and -9 and TIMP-1 and -2, as the major metalloproteinases (and their inhibitors) implicated in pathophysiology of vascular disease. METHODS: Venous citrated blood was collected from 93 normal healthy volunteers from four ethnic groups (Afro-Caribbean, South Asian, Caucasian and Far Eastern) for a cross-sectional study. In addition, 20 separate healthy volunteers were studied during supine rest, before and immediately following peak treadmill stress using a Bruce protocol. MMP-2 and -9 and TIMP-1 and -2 were all measured by ELISA. RESULTS: There was a categorical distribution of MMP-2 concentration with individual subjects showing high levels, yet others being undetectable, although these changes were unrelated to age, gender or ethnicity. TIMP-1 and -2 showed a modest negative correlation with age (r=-0.251, p=0.015; r=-0.254, p=0.014). There was a positive correlation between MMP-2 and TIMP-2 (r=0.399, p<0.001), MMP-9 and TIMP-1 (r=0.45, p<0.001) and between TIMP-1 and TIMP-2 (r=0.275, p=0.008). When adjusted for age and gender, there were no significant differences in MMP-2 and TIMP-1 and -2 between the four ethnic groups. MMP-9 was significantly lower in the Far Eastern group compared to the other three ethnic groups (p=0.012). Only TIMP-1 (p=0.042) and TIMP-2 (p=0.024) were significantly altered after exercise. CONCLUSION: Age and exercise both have modest effects on circulating concentrations of TIMP-1 and-2. MMP-9 appears lower in individuals of Far Eastern/Chinese origin regardless of age or gender. The positive association between MMPs and TIMPs suggests that in healthy individuals, enzyme activity may be regulated by this interaction. The reasons for the categorical distribution of MMP-2 remain unclear but this would be important in any studies designed to use circulating MMPs as a surrogate for tissue MMPs around clinical events, such as myocardial infarction or in response to therapies affecting extracellular matrix composition.

Adult↗

PubMed2001

Nitric oxide and mechanisms of redox signalling: matrix and matrix-metabolizing enzymes as prime nitric oxide targets.

One of the greatest biomedical breakthroughs of the twentieth century was the discovery of endothelium-derived relaxing factor and its identification as nitric oxide (NO). NO has received special attention ever since: besides its potent vasodilatory and vasoprotective effects, NO was identified as a key player in innate immunity and was found to act as an unconventional type of neurotransmitter. This article focuses on mechanisms of NO signalling that form the basis of functional cell responses to accommodate changes in the cellular microenvironment. Redox-based regulation of signal transduction and, on a more long-term scale, changes in gene expression will be exemplified by NO-modulation of matrix components and matrix-metabolizing enzymes. It seems to be a safe bet that ongoing analyses of NO signalling and gene expression will provide a wealth of promising therapeutic targets in human diseases.

Animals↗

PubMed2002

Matrix metalloproteinase-2, membranous type 1 matrix metalloproteinase, and tissue inhibitor of metalloproteinase-2 expression in ectopic and eutopic endometrium.

OBJECTIVE: To investigate expression of matrix metalloproteinase-2 (MMP-2), membranous type 1 matrix metalloproteinase (MT1-MMP), and tissue inhibitor of metalloproteinase-2 (TIMP-2) in ectopic and eutopic endometrium from women with and without endometriosis throughout the menstrual cycle. DESIGN: Molecular studies in human tissue. SETTING: Reproductive immunology laboratory of a university medical center. PATIENT(S): Fifty-three premenopausal woman (23 with endometriosis and 30 without endometriosis) undergoing laparoscopic surgery. Endometrium and ectopic endometriosis tissue were obtained at the time of surgery. MAIN OUTCOME MEASURE(S): Messenger RNA and protein expression from eutopic and ectopic endometrium was analyzed by using quantitative competitive polymerase chain reaction, zymography, and Western blot assay. RESULT(S): Uterine endometrium from women with endometriosis expressed higher levels of MMP-2 and MT1-MMP and lower levels of TIMP-2 than did endometrium from normal women. CONCLUSION(S): Eutopic endometrium from patients with endometriosis may be more invasive and prone to peritoneal implantation because of greater expression of MMP-2 and MT1-MMP and lower expression of TIMP-2 messenger RNA, compared with endometrium from women without endometriosis. Thus, increased proteolytic activity may help to explain the invasive factors that result in endometriosis.

Adult↗

PubMed2000

Use of Edman degradation sequence analysis and matrix-assisted laser desorption/ionization mass spectrometry in designing substrates for matrix metalloproteinases.

The matrix metalloproteinase (MMP) family has been implicated in the process of a variety of diseases such as arthritis, atherosclerosis, and tumor cell metastasis. We have been designing single-stranded peptides (SSPs) and triple-helical peptides (THPs) as potential discriminatory MMP substrates. Edman degradation sequence and matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) analyses of proteolytic activity have been utilized to aid in further substrate design. THP models of the alpha1(I)772-786 sequence from type I collagen were synthesized to examine the triple-helical substrate specificity of MMP family members. Sequence and MALDI-MS analyses were used in conjunction with a fluorometric assay to determine the exact point of cleavage by each MMP. MMP-1 (interstitial collagenase) cleaved the substrates at a single Gly-Ile bond, analogous to the cleavage site in type I collagen. MMP-2 (Mr 72 000 type IV collagenase; gelatinase A) was found to cleave the substrates at two sites, a Gly-Ile bond and a Gly-Gln bond. MMP-3 (stromelysin 1) was found to cleave only one of the substrates after reaction for 48 h. Ultimately, sequence and MALDI-MS analyses allowed us to detect an additional cleavage site for MMP-2 in comparison to MMP-1, while MMP-3 was found to cleave a substrate after an extended time period. The second cleavage site would cause the kinetic parameters for MMP-2 to be overestimated by the fluorometric assay. Further design variations for these substrates need to consider the presence of more stable triple-helical conformation (to eliminate MMP-3 binding) and the removal of Gly-Gln bonds that may be susceptible to MMP-2.

Amino Acid Sequence↗

PubMed2003

Membrane type I matrix metalloproteinase usurps tumor growth control imposed by the three-dimensional extracellular matrix.

Cancer cells are able to proliferate at accelerated rates within the confines of a three-dimensional (3D) extracellular matrix (ECM) that is rich in type I collagen. The mechanisms used by tumor cells to circumvent endogenous antigrowth signals have yet to be clearly defined. We find that the matrix metalloproteinase, MT1-MMP, confers tumor cells with a distinct 3D growth advantage in vitro and in vivo. The replicative advantage conferred by MT1-MMP requires pericellular proteolysis of the ECM, as proliferation is fully suppressed when tumor cells are suspended in 3D gels of protease-resistant collagen. In the absence of proteolysis, tumor cells embedded in physiologically relevant ECM matrices are trapped in a compact, spherical configuration and unable to undergo changes in cell shape or cytoskeletal reorganization required for 3D growth. These observations identify MT1-MMP as a tumor-derived growth factor that regulates proliferation by controlling cell geometry within the confines of the 3D ECM.

Animals↗

PubMed2003

Matrix metalloproteinase-7 and matrix metalloproteinase-9 are associated with unfavourable prognosis in superficial oesophageal cancer.

If oesophageal carcinoma is detected in the superficial stage, the prognosis is better than for advanced oesophageal carcinoma. But the factors which predict the prognosis and treatment policy remain unclear. Matrix metalloproteinase-7 (MMP-7) and matrix metalloproteinase-9 (MMP-9) have been reported to have close associations with tumour invasion and metastasis. In this study, we retrospectively studied the relations between MMP-7 and MMP-9 expression in immunohistochemistry, clinicopathologic factors, and prognosis in 55 superficial oesophageal carcinomas. MMP-7 and MMP-9 expression occurred in 23.6% and 47.3% of the patients, respectively. MMP-7 expression was significantly correlated with the presence of nodal metastasis (P=0.004). MMP-9 expression was significantly correlated with the depth of tumour invasion (P=0.004), lymphatic permeation (P=0.001), nodal metastasis (P=0.049), and pathologic differentiation grade (P=0.003). By the log-rank test, MMP-7 expression and MMP-9 expression on the invasive front were related to the prognosis. In multivariate analysis, MMP-9 expression on the invasive front was an independent prognostic indicator. The combined expression of MMP-7 and MMP-9 may be a good marker for the degree of malignancy of oesophageal cancer and for the presence of lymphatic metastasis.

Adenocarcinoma↗

PubMed1999

Matrix metalloproteinases in human melanoma cell lines and xenografts: increased expression of activated matrix metalloproteinase-2 (MMP-2) correlates with melanoma progression.

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are involved in tumour progression and metastasis. In this study, we investigated the in vitro and in vivo expression patterns of MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1 and TIMP-2 mRNA and protein in a previously described human melanoma xenograft model. This model consists of eight human melanoma cell lines with different metastatic behaviour after subcutaneous (s.c.) injection into nude mice. MMP-1 mRNA was detectable in all cell lines by reverse transcription polymerase chain reaction (RT-PCR), but the expression was too low to be detected by Northern blot analysis. No MMP-1 protein could be found using Western blotting. MMP-2 mRNA and protein were present in all cell lines, with the highest expression of both latent and active MMP-2 in the highest metastatic cell lines MV3 and BLM. MMP-3 mRNA was expressed in MV3 and BLM, and in the non-metastatic cell line 530, whereas MMP-3 protein was detectable only in MV3 and BLM. None of the melanoma cell lines expressed MMP-9. TIMP-1 and TIMP-2 mRNA and protein, finally, were present in all cell lines. A correlation between TIMP expression level and metastatic capacity of cell lines, however, was lacking. MMP and TIMP mRNA and protein expression levels were also studied in s.c. xenograft lesions derived from a selection of these cell lines. RT-PCR analysis revealed that MMP-1 mRNA was present in MV3 and BLM xenografts, and to a lesser extent in 530. Positive staining for MMP-1 protein was found in xenograft lesions derived from both low and high metastatic cell lines, indicating an in vivo up-regulation of MMP-1. MMP-2 mRNA was detectable only in xenografts derived from the highly metastatic cell lines 1F6m, MV3 and BLM. In agreement with the in vitro results, the highest levels of both latent and activated MMP-2 protein were observed in MV3 and BLM xenografts. With the exception of MMP-9 mRNA expression in 530 xenografts, MMP-3, MMP-9, and TIMP-1 mRNA and protein were not detectable in any xenograft, indicating a down-regulated expression of MMP-3 and TIMP-1 in vivo. TIMP-2 mRNA and protein were present in all xenografts; interestingly, the strongest immunoreactivity of tumour cells was found at the border of necrotic areas. Our study demonstrates that of all tested components of the matrix metalloproteinase system, only expression of activated MMP-2 correlates with increased malignancy in our melanoma xenograft model, corroborating an important role of MMP-2 in human melanoma invasion and metastasis.

Animals↗

PubMed2007

Comparison of extracellular matrix in skin and saphenous veins from patients with varicose veins: does the skin reflect venous matrix changes?

Varicose vein disease is a frequently occurring pathology with multifactorial causes and a genetic component. An intense remodelling of the varicose vein wall has been described and could be at the origin of its weakness and altered elasticity. We have described previously a dysregulation of collagen synthesis in cultured smooth muscle cells from saphenous veins and in dermal fibroblasts from the skin of patients with varicose veins, suggesting a systemic defect in their connective tissue. The present study describes comparative morphological and immunohistochemical data in both the skin and saphenous veins of eight control subjects (undergoing coronary bypass surgery) and eight patients with varicose veins. Histological staining of glycoproteins, the elastic fibre network and collagen bundles showed that the remodelling and fragmentation of elastic fibres observed in varicose veins were also present in the skin of the patients. When compared with control subjects, we observed in both the veins and skin of patients with varicose veins (i) an increase in the elastic network, as quantified by image analysis; (ii) an accumulation of collagen type I, fibrillin-1 and laminin; and (iii) an overproduction of MMP (matrix metalloproteinase)-1, MMP-2 and MMP-3, analysed by immunohistochemistry, but normal levels of other MMPs (MMP-7 and MMP-9) and their inhibitors (TIMP-1, TIMP-2 and TIMP-3). An imbalance of extracellular matrix production/degradation was thus observed in veins as well as in the skin of the patients with varicose veins and, taken together, these findings show that remodelling is present in different organs, confirming systemic alterations of connective tissues.

Adult↗

PubMed2001

Skin and oral fibroblasts exhibit phenotypic differences in extracellular matrix reorganization and matrix metalloproteinase activity.

BACKGROUND: Oral mucosal wounds are characterized by rapid re-epithelialization and remodelling. In vitro, oral mucosal fibroblasts exhibit a fetal phenotype with increased extracellular matrix reorganizational ability, migration and experimental wound repopulation when compared with skin fibroblasts. OBJECTIVES: To investigate whether phenotypic differences in the expression and production of matrix metalloproteinase (MMP) -2 and tissue inhibitors of metalloproteinases (TIMPs) could play an important part in mediating these in vitro differences. METHODS: Skin and oral mucosal fibroblast MMP-2, TIMP-1 and TIMP-2 mRNA expression and protein production were studied in three-dimensional collagen lattices using quantitative competitive reverse transcriptase-polymerase chain reaction (QCRT-PCR), enzyme-linked immunosorbent assay (ELISA), zymography and reverse zymography. RESULTS: Oral mucosal fibroblasts exhibited increased levels of the 62-kDa active form of MMP-2 and lattice contraction when compared with skin fibroblasts. Oral mucosal and skin fibroblast MMP-2 gene expression and synthesis of the 72-kDa pro-MMP-2 was similar as assessed by QCRT-PCR, zymography and ELISA. Differential MMP-2 activation was, however, related to phenotypic differences in TIMP activity between the skin and oral mucosal fibroblasts, as assessed by reverse zymography. CONCLUSIONS: These studies propose a mechanism by which fibroblast phenotype may contribute directly to the observed preferential remodelling of oral wounds.

Adolescent↗

PubMed1998

Matrix metalloproteinase-2 and matrix metalloproteinase-9 in cholesteatoma and deep meatal skin.

A qualitative and quantitative study of the presence of Matrix metalloproteinase-2 (MMP-2) and Matrix metalloproteinase-9 (MMP-9) in cholesteatoma was performed. Ten cholesteatoma and four deep meatal skin specimens were analysed for gelatinase activity at molecular weights corresponding to MMP-2 and MMP-9 using Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS PAGE) Zymography. Gelatinase activity at 72 kDa and 92 kDa was investigated. Western blotting was employed using primary monoclonal antibodies to provide a qualitative assessment of MMP-2 and MMP-9. Non-parametric data analysis using the Mann-Whitney U test did not show a significant difference in expression of MMP-2 (P = 0.51) or MMP-9 (P = 0.14) between the two tissue types. Western blotting showed the presence of both MMP-2 and MMP-9 in the majority of specimens, both cholesteatoma and deep meatal skin.

Blotting, Western↗