Higher Matrix Metalloproteinase-9 Research Articles

MMP-9/TIMP-1 imbalance induced in human dendritic cells by Porphyromonas gingivalis.

Matrix metalloproteinase-9 (MMP-9) cleaves collagen, allowing leukocytes to traffic toward the vasculature and the lymphatics. When MMP-9 is unregulated by tissue inhibitor of metalloproteinase-1 (TIMP-1), this can lead to tissue destruction. Dendritic cells (DCs) infiltrate the oral mucosa increasingly in chronic periodontitis, characterized by infection with several pathogens including Porphyromonas gingivalis. In this study, human monocyte-derived DCs were pulsed with different doses of lipopolysaccharide of P. gingivalis 381 and of Escherichia coli type strain 25922, as well as whole live isogenic fimbriae-deficient mutant strains of P. gingivalis 381. Levels of induction of MMP-9 and TIMP-1, as well as interleukin-10 (IL-10), which reportedly inhibits MMP-9 induction, were measured by several approaches. Our results reveal that lipopolysaccharide of P. gingivalis, compared with lipopolysaccharide from E. coli type strain 25922, is a relatively potent inducer of MMP-9, but a weak inducer of TIMP-1, contributing to a high MMP-9/TIMP-1 ratio.Whole live P. gingivalis strain 381, major fimbriae mutant DPG-3 and double mutant MFB were potent inducers of MMP-9, but minor fimbriae mutant MFI was not. MMP-9 induction was inversely proportional to IL-10 induction. These results suggest that lipopolysaccharide and the minor and the major fimbriae of P. gingivalis may play distinct roles in induction by DCs of MMP-9, a potent mediator of local tissue destruction and leukocyte trafficking.

MMP-7 overexpression is an independent prognostic marker in gastric cancer

To enable cancer to invade and to metastasize, the surrounding stroma must be degraded. Matrix metalloproteinase-7 (MMP-7) is capable of degrading many extracellular matrix proteins and cellular adhesions, is overexpressed in many malignancies, and plays a role in tumour progression. The purpose of this study was to evaluate the association between MMP-7 tissue expression and patients' prognosis in gastric cancer. From 264 patients who underwent surgery for gastric cancer, surgical specimens were collected on tissue array blocks and stained by immunohistochemistry for MMP-7. In 27 (10.2%) of the specimens, immunopositivity was found as high, in 50 (18.9%) as moderate and in 51 (19.3%) as weak. In 136 cases (51.5%), the immunopositivity was negative. A statistically significant correlation appeared between high MMP-7 expression and poor survival. In conclusion, our results suggest that MMP-7 expression may prove helpful in evaluating gastric cancer prognosis.

Computational Study of Proteolysis-Driven Single Cell Migration in a Three-Dimensional Matrix

Cell migration is a fundamental process that is crucial to a variety of physiological events. While traditional approaches have focused on two-dimensional (2D) systems, recent efforts have shifted to studying migration in three-dimensional (3D) matrices. A major distinction that has emerged is the increased importance of cell-matrix interactions in 3D environments. In particular, cell motility in 3D matrices is more dependent on matrix metalloproteinases (MMPs) to degrade steric obstacles than in 2D systems. In this study, we implement the effects of MMP-mediated proteolysis in a force-based computational model of 3D migration, testing two matrix ligand-MMP relationships that have been observed experimentally: linear and log-linear. The model for both scenarios predicts maximal motility at intermediate matrix ligand and MMP levels, with the linear case providing more physiologically compelling results. Recent experimental results suggesting MMP influence on integrin expression are also integrated into the model. While the biphasic behavior is retained, with MMP-integrin feedback peak cell speed is observed in a low ligand, high MMP regime instead of at intermediate ligand and MMP levels for both ligand-MMP relationships. The simulation provides insight into the expanding role of cell-matrix interactions in cell migration in 3D environments and has implications for cancer research.

Association of matrix metalloproteinase 9 genotypes and cardiovascular disease risk factors with serum matrix metalloproteinase 9 concentrations in Taiwanese individuals

Circulating concentrations of matrix metalloproteinase 9 (MMP-9) are associated with cardiovascular disease mortality in patients with coronary artery disease. We investigated the determinants of MMP-9 concentrations by analyzing MMP-9 genotypes and risk factors for cardiovascular disease. A total of 596 individuals were recruited for this study. Six single nucleotide polymorphisms (SNP) with coverage of the MMP-9 gene region were analyzed; and two genotypes, rs3918242-TT and rs2274756-AA, which were in nearly complete linkage disequilibrium, were associated with higher MMP-9 values (p=0.007 and p=0.008, respectively). In age- and gender-adjusted regression models, MMP-9 concentrations were positively associated with the homeostasis model assessment of insulin resistance (HOMA-IR) index and triglyceride concentrations, fasting serum insulin, fasting plasma glucose, C-reactive protein, fibrinogen, and serum amyloid A. By multivariate analysis, rs2274756 genotypes, age, smoking status, fibrinogen and fasting plasma glucose concentrations were all independently associated with MMP-9 (p=0.007, p=0.033, p=0.003, p=0.013, and p=0.012, respectively). The rs2274756-AA and rs3918242-TT genotypes, younger age, current smoking status and increased fasting plasma glucose, and fibrinogen concentrations were independently associated with high serum MMP-9 concentrations in Taiwanese individuals.

Development of a Gene Therapy Virus with a Glucocorticoid-Inducible MMP1 for the Treatment of Steroid Glaucoma

To design a glucocorticoid-inducible virus vector overexpressing recombinant matrix metalloproteinase 1 (MMP1) and counteract extracellular matrix deposition in the trabecular meshwork only when steroid is present. Endogenous MMP1 expression was measured in primary human trabecular meshwork cells (HTM) treated with dexamethasone (DEX), triamcinolone acetate, and prednisolone acetate by TaqMan PCR. Wild-type and mutant MMP1 cDNAs were cloned downstream of a glucocorticoid response element (GRE) and P(TAL) promoter. Adenoviruses AdhGRE.MMP1 and AdhGRE.mutMMP1 were generated by homologous recombination. HTM cells and perfused human anterior segments were infected with the viruses, with and without DEX. MMP1 mRNA and protein were analyzed by TaqMan PCR, Western blot analysis, and ELISA. Activity of secreted MMP1 was evaluated by FRET and rat tail collagen type I assays. Immunohistochemistry was performed by double-labeling with anti-human MMP1 and collagen type I antibodies. Endogenous MMP1 expression was greatly downregulated by the steroids. DEX-treated cells and perfused organ cultures infected with AdhGRE.MMP1 secreted high levels of MMP1. Induction of MMP1 cycled on and off with the addition or removal of DEX. Secreted wild-type MMP1 degraded collagen type I after activation, whereas secreted mutMMP1 did not. Immunohistochemistry showed faint staining of collagen type I in areas of trabecular meshwork with high MMP1 transgene expression. The authors have developed a novel glucocorticoid-inducible adenovirus vector that overproduces MMP1 only in the presence of DEX. The availability of this vector sets up the foundation for the development of gene therapy drugs for the potential treatment of ocular hypertension in steroid-responsive patients.

Prognostic significance of matrix metalloproteinase-1 levels in peripheral plasma and tumour tissues of lung cancer patients

Matrix metalloproteinase-1 (MMP-1) participates in a variety of physiological and pathological processes. We previously found that MMP-1 was one of the lung cancer-related proteins detectable in peripheral blood. To validate our preliminary observations and explore the clinical significance of MMP-1 for lung cancer further, we carried out the present study. The concentrations of MMP-1 in circulating plasma specimens of 170 lung cancer patients and 70 healthy individuals were measured by an enzyme-linked immunosorbance assay. The expression status of the MMP-1 in archival tissue samples from 122 lung cancer patients was examined by immunohistochemical analysis. The correlation between the MMP-1 levels and prognosis of the lung cancer patients was then assessed statistically. Protein levels of MMP-1 were considerably raised in the plasma from lung cancer patients relative to those in healthy controls. The high plasma MMP-1 levels were associated with advanced-stage of the disease and significantly lower overall survival rate of the patients. Coincidently, MMP-1 protein extraordinarily overexpressed in the tumour tissues of lung cancer; and the up-regulated MMP-1 was associated with the progression (including tumour size, staging and lymphatic invasion), especially with decreased survival rate of the patients. Statistic analysis revealed that MMP-1 protein levels had an independent influence on survival. MMP-1 levels were elevated in both tumour tissue and blood; the latter may serve as an independent predictor for survival of lung cancer patients. MMP-1 protein levels in plasma/serum thus represent a potential and clinically relevant biomarker for the prognosis of patients with lung cancers.

Prognostic Significance of Matrix Metalloproteinase-9 (MMP-9) in Stage II Colorectal Carcinoma

Approximately 30% of all colorectal cancer patients are diagnosed with stage II disease. Adjuvant therapy is not widely recommended. However, it is well-established that a subgroup of patients with stage II is at high risk for recurrence within their life time and should be considered for adjuvant chemotherapy. The present work was designed to assess the value of matrix metalloproteinase-9 (MMP-9) as a predictor of disease outcome in a series of 202 stage II colorectal cancer (CRC) patients with long-term follow-up. The present study comprises a series of 202 patients who underwent bowel resection for stage II CRC at Turku University Hospital. Archival paraffin-embedded CRC tissue samples were used to prepare tissue microarray blocks for immunohistochemical staining with MMP-9 antibody. Forty-eight percent of all CRC samples were positive for MMP-9. There was no significant correlation between MMP-9 expression and age, depth of invasion, and lymph node status. However, MMP-9 expression was significantly related to histological grade (p = 0.03) and location of the tumor (p = 0.01), therefore, being lower in high-grade tumors and most intense in carcinomas of the descending colon and rectum. Tumors with high MMP-9 expression showed a higher recurrence rate than tumors with low expression (p = 0.02). MMP-9 negative tumors had a more favorable disease-free survival (DFS) than those expressing MMP-9 (p = 0.03). The same was true with disease-specific survival (DSS; p = 0.02) as well, high expression of MMP-9 being associated with shorter survival rates. In multivariate (Cox) survival analysis, MMP-9 expression proved to be an independent predictor of DFS, but not DSS, which was predicted by age and sex only. Quantification of MMP-9 expression seems to provide valuable prognostic information in stage II CRC, particularly, in selecting the patients at high risk for recurrent disease who might benefit from adjuvant therapy.

Increased Matrix Metalloproteinase-9 Predicts Poor Wound Healing in Diabetic Foot Ulcers

In a recent study by Liu et al. (1), the complex mechanisms of diabetic foot ulcers were further elucidated. In a series of 62 ulcers, the authors report that they found—for the first time—a positive correlation between a high matrix metalloproteinase-9 (MMP-9)–to–tissue inhibitor of metalloproteinase-1 (TIMP-1) ratio and poor wound healing. However, these are not the first data enhancing the putative role of MMP-9 in the pathogenesis of chronic wounds. Ladwig et al. (2) also described a positive correlation between a high MMP-9–to–TIMP-1 ratio and poor wound healing …

High Matrix Metalloproteinase Activity Is a Hallmark of Periapical Granulomas

Introduction The inability to distinguish periapical cysts from granulomas before performing root canal treatment leads to uncertainty in treatment outcomes because cysts have lower healing rates. Searching for differential expression of molecules within cysts or granulomas could provide information with regard to the identity of the lesion or suggest mechanistic differences that may form the basis for future therapeutic intervention. Thus, we investigated whether granulomas and cysts exhibit differential expression of extracellular matrix (ECM) molecules. Methods Human periapical granulomas, periapical cysts, and healthy periodontal ligament tissues were used to investigate the differential expression of ECM molecules by microarray analysis. Because matrix metalloproteinases (MMP) showed the highest differential expression in the microarray analysis, MMPs were further examined by in situ zymography and immunohistochemistry. Data were analyzed by using one-way analysis of variance followed by the Tukey test. Results We observed that cysts and granulomas differentially expressed several ECM molecules, especially those from the MMP family. Compared with cysts, granulomas exhibited higher MMP enzymatic activity in areas stained for MMP-9. These areas were composed of polymorphonuclear cells (PMNs) in contrast to cysts. Similarly, MMP-13 was expressed by a greater number of cells in granulomas compared with cysts. Conclusion Our findings indicate that high enzymatic MMP activity in PMNs together with MMP-9 and MMP-13 stained cells could be a molecular signature of granulomas unlike periapical cysts.

Ischemic injury, hemorrhagic transformation and plasma MMP‐9 profile in experimental diabetes vs. hyperglycemia

Diabetes increases stroke risk. We recently showed cerebrovascular remodeling associated with higher matrix metalloproteinase (MMP) activity and increased hemorrhagic transformation (HT) following 3 h middle cerebral artery occlusion /21 h reperfusion in Type 2 diabetes. Plasma MMP‐9 may be predictive of HT following tPA treatment in stroke. Thus, the goals of this study were to measure plasma MMP‐9 before and after stroke in control and Type 2 diabetic Goto‐Kakizaki (GK) rats and in acutely hyperglycemic rats during stroke. The hypothesis was that baseline plasma MMP‐9 activity is higher in GKs and is further elevated after ischemia. Plasma MMP‐9 activity was determined at baseline and at sacrifice after 3/21 MCAO/reperfusion by zymography. Basal MMP‐9 activity was higher in GKs (11.2 ± 4.1 vs. 0.7 ± 0.3, n=6, p<0.001). MCAO/reperfusion significantly increased plasma MMP‐9 in control, diabetic and acute hyperglycemia rats (103 ± 23.2, 113 ± 15, 124 ± 9, respectively, n=3‐6, p<0.0001 vs. baseline) but there was no difference between groups. Infarct size was smaller in GK (11 ± 4%, n=3, p<0.01) vs. control (42 ± 6%, n=4) and hyperglycemic (47 ± 6%, n=4) rats. Control animals had no HT yet there was macroscopic bleeding in GK and hyperglycemic rats. These results suggest that 24 h plasma MMP‐9 levels are not associated with higher bleeding in diabetic and hyperglycemic rats and earlier time points merit evaluation.

Adipose tissue is not an important source for matrix metalloproteinase-9 in the circulation

Objectives: Matrix metalloproteinase 9 (MMP-9) is overexpressed in atherosclerotic plaques and in many cancers, and has emerged as a potential circulating biomarker for such diseases. However, adipose tissue (AT) might also produce circulating MMP-9, thereby reducing the value of MMP-9 as a biomarker. The aim of this study was to evaluate the impact of AT on circulating MMP-9, and if the metabolic syndrome might have a modifying effect. Methods: Gene expression of MMP-9 was measured in AT, isolated adipocytes, atherosclerotic plaques, macrophages and various other human tissues using real-time PCR. Relationships between plasma MMP-9 (ELISA), adiposity, and metabolic syndrome were analyzed in a population-based cohort of 61-year-old men (n=513). Both AT mRNA levels and circulating levels of MMP-9 were measured in obese subjects (n=40) with and without the metabolic syndrome, treated with a weight-reducing diet. Results: Bone marrow, atherosclerotic plaques and macrophages had considerably higher MMP-9 mRNA than subcutaneous AT and isolated adipocytes. Among the 61-year-old men, active plasma MMP-9 concentrations were associated with several metabolic syndrome factors, and inflammatory markers, but not body mass index (BMI). In obese patients with, but not without metabolic syndrome AT mRNA levels and circulating MMP-9 declined during weight reduction, but there was no association between changes in plasma MMP-9 and BMI. Conclusion: The results show that adipose tissue per se is not associated with circulating MMP-9. Components of the metabolic syndrome, such as circulating insulin and glucose were related to plasma MMP-9 both in the observation and dietary weight loss studies.

Prognostic relevance of TTF-1 and MMP-9 expression in advanced lung adenocarcinoma

Background The thyroid transcription factor-1 (TTF-1) is a tissue-specific transcription factor that could play an important role in cell differentiation and morphogenesis of lung tumors. Matrix metalloproteinase-9 (MMP-9) is a protease commonly expressed in non-small cell lung cancer, conferring angiogenic and metastatic potential. Methods We assessed TTF-1 and MMP-9 tumor expression by immunohistochemistry in 51 patients with lung adenocarcinoma, stage IIIB or IV, treated with platinum regimens. A bicategorical prognostic model was obtained using the Kaplan–Meier method, Cox regression, and conjunctive consolidation. Results The median expression of TTF-1 was 30.0% (range: 0–85.9%). All tumors expressed MMP-9 (median: 78.7%; range: 15.2–96.1%). Median survival was 41.6 weeks, with estimated 1- and 2-year survival rates of 45.0% and 22.0%, respectively. Poor performance status (Karnofsky scale) – hazards ratio (HR): 1.03, 95% confidence interval (CI): 1.01–1.06; low TTF-1 expression (<40%) – HR: 4.00, 95% CI: 1.75–9.09; and high MMP-9 expression (≥80%) – HR: 2.82, 95% CI: 1.30–6.08 were independent prognostic factors. Patients could be stratified in three death risk groups according to markers expression: low risk (high TTF-1 and low MMP-9; median survival: 127.6 weeks), intermediate risk (low TTF-1 or high MMP-9; median survival: 39.0 weeks); and high risk (low TTF-1 and high MMP-9; median survival: 16.4 weeks). Conclusion TTF-1 and MMP-9 tumor expression as detected by immunohistochemistry may allow identification of different, clinically meaningful, prognostic groups of advanced lung adenocarcinoma patients treated with platinum regimens.

TNF-alpha-mediated inflammation in cerebral aneurysms: a potential link to growth and rupture.

Intracranial aneurysm (IA) rupture is one of the leading causes of stroke in the United States and remains a major health concern today. Most aneurysms are asymptomatic with a minor percentage of rupture annually. Regardless, IA rupture has a devastatingly high mortality rate and does not have specific drugs that stabilize or prevent aneurysm rupture, though other preventive therapeutic options such as clipping and coiling of incidental aneurysms are available to clinicians. The lack of specific drugs to limit aneurysm growth and rupture is, in part, attributed to the limited knowledge on the biology of IA growth and rupture. Though inflammatory macrophages and lymphocytes infiltrate the aneurysm wall, a link between their presence and aneurysm growth with subsequent rupture is not completely understood. Given our published results that demonstrate that the pro-inflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), is highly expressed in human ruptured aneurysms, we hypothesize that pro-inflammatory cell types are the prime source of TNF-alpha that initiate damage to endothelium, smooth muscle cells (SMC) and internal elastic lamina (IEL). To gain insights into TNF-alpha expression in the aneurysm wall, we have examined the potential regulators of TNF-alpha and report that higher TNF-alpha expression correlates with increased expression of intracellular calcium release channels that regulate intracellular calcium (Ca2+), and Toll like receptors (TLR) that mediate innate immunity. Moreover, the reduction of tissue inhibitor of metalloproteinase-1 (TIMP-1) expression provides insights on why higher matrix metalloproteinase (MMP) activity is noted in ruptured IA. Because TNF-alpha is known to amplify several signaling pathways leading to inflammation, apoptosis and tissue degradation, we will review the potential role of TNF-alpha in IA formation, growth and rupture. Neutralizing TNF-alpha action in the aneurysm wall may have a beneficial effect in preventing aneurysm growth by reducing inflammation and arterial remodeling.

Increased expression of matrix metalloproteinase-2 (MMP-2) predicts tumour recurrence and unfavourable outcome in non-small cell lung cancer.

The purpose of this study was to analyse the expression of matrix metalloproteinase-2 (MMP-2) and its extracellular matrix metalloproteinase inducer (EMMPRIN) in non-small cell lung cancer (NSCLC), and to evaluate their significance to predict tumour behaviour. The study consists of 212 patients treated by the resection of the tumour. Tumour samples were stained immunohistochemically, and the expression of MMP-2 and EMMPRIN was evaluated both in tumour cells and in peritumoural stromal tissue. The results were compared with clinicopathological factors and survival of the patients. High expression of MMP-2 in tumour cells was found in 83 out of 191 cases (44%). Adenocarcinomas showed more often high expression of MMP-2 as compared with squamous cell or large cell carcinomas (p=0.001). High cancer cell associated MMP-2 expression was associated with increased tumour recurrence (p=0.001). Tumour stroma showed positive staining in 162 (98%) cases and was considered highly stained in 120 (72%) cases. The high stromal MMP-2 expression was noticed more often among large cell carcinomas as compared with other histological types (p=0.007). High cancer cell associated EMMPRIN expression was found in 115 (61%) cases and was associated only with high MMP-2 expression in tumour cells (p=0.006). In overall survival (OS) and disease free survival (DFS) analyses, type of tumour (p=0.001 and p=0.0004), advanced stage (p=0.001 and p=0.013) and high MMP-2 expression in tumour cells (p=0.018 and p=0.001) were associated with poor survival. Also, high stromal MMP-2 expression was related to poor outcome in both OS and DFS analyses (p=0.010 and 0.045, respectively). In multivariate analysis, stromal MMP-2 expression retained its prognostic value to predict OS and DFS (p=0.028 and p=0.039, respectively), together with tumour type and stage (p=0.017, p=0.001 and p=0.021, p=0.008, respectively). The present study shows the significant prognostic value of MMP-2 in NSCLC suggesting that the use of MMP-2 is valuable in determining the patients with more aggressive disease.

EVIDENCE OF INFLAMMATORY CELL INVOLVEMENT IN BRAIN ARTERIOVENOUS MALFORMATIONS

Brain arteriovenous malformations (AVM) have high matrix metalloproteinase-9, interleukin-6, and myeloperoxidase (MPO) expression, and polymorphic variations in inflammatory genes are associated with an increased risk of hemorrhage. In this study, we characterized the presence of inflammatory cells in AVM lesional tissue specimens. Immunohistochemistry was used to identify and localize neutrophils (MPO as marker), macrophages/microglia (CD68 as marker), T lymphocytes (CD3 as marker), and B lymphocytes (CD20 as marker). Endothelial cell (EC) marker CD31 was used as an index to assess vascular mass (EC mass). Surgical specimens from 20 unruptured, nonembolized AVMs were examined; seven cortical samples from temporal lobectomy were used as controls. Positive signals for inflammatory cell markers were counted and analyzed by normalizing to the area of the tissue section and the amount of endothelial cells (cells/mm/EC mass pixels). Levels of MPO and matrix metalloproteinase 9 were determined by enzyme-linked immunosorbent assay. Neutrophils and macrophages are all frequently identified in the vascular wall of AVM tissue. In contrast, T and B lymphocytes are rarely observed in AVM tissue. AVM tissue displayed more neutrophil and macrophage/microglia markers than epilepsy control tissue (MPO: 434 +/- 333 versus 5 +/- 4, P = 0.0001; CD68: 454 +/- 404 versus 4 +/- 2, P = 0.0001; cells/mm/EC mass pixels). In ex vivo studies, neutrophil quantity, MPO, and matrix metalloproteinase-9 levels were all colinear (R = 0.98-0.99). Our study demonstrates that inflammatory cells are present in AVM tissue. Taken together with previous genetic and cytokine studies, these data are consistent with a novel view that inflammation is associated with AVM disease progression and rupture.

EVIDENCE OF INFLAMMATORY CELL INVOLVEMENT IN BRAIN ARTERIOVENOUS MALFORMATIONS

OBJECTIVE Brain arteriovenous malformations (AVM) have high matrix metalloproteinase-9, interleukin-6, and myeloperoxidase (MPO) expression, and polymorphic variations in inflammatory genes are associated with an increased risk of hemorrhage. In this study, we characterized the presence of inflammatory cells in AVM lesional tissue specimens. METHODS Immunohistochemistry was used to identify and localize neutrophils (MPO as marker), macrophages/microglia (CD68 as marker), T lymphocytes (CD3 as marker), and B lymphocytes (CD20 as marker). Endothelial cell (EC) marker CD31 was used as an index to assess vascular mass (EC mass). Surgical specimens from 20 unruptured, nonembolized AVMs were examined; seven cortical samples from temporal lobectomy were used as controls. Positive signals for inflammatory cell markers were counted and analyzed by normalizing to the area of the tissue section and the amount of endothelial cells (cells/mm2/EC mass pixels). Levels of MPO and matrix metalloproteinase 9 were determined by enzyme-linked immunosorbent assay. RESULTS Neutrophils and macrophages are all frequently identified in the vascular wall of AVM tissue. In contrast, T and B lymphocytes are rarely observed in AVM tissue. AVM tissue displayed more neutrophil and macrophage/microglia markers than epilepsy control tissue (MPO: 434 ± 333 versus 5 ± 4, P = 0.0001; CD68: 454 ± 404 versus 4 ± 2, P = 0.0001; cells/mm2/EC mass pixels). In ex vivo studies, neutrophil quantity, MPO, and matrix metalloproteinase-9 levels were all colinear (R2 = 0.98–0.99). CONCLUSION Our study demonstrates that inflammatory cells are present in AVM tissue. Taken together with previous genetic and cytokine studies, these data are consistent with a novel view that inflammation is associated with AVM disease progression and rupture.

Plasma matrix metalloproteinase‐7 as a metastatic marker and survival predictor in patients with renal cell carcinomas

We evaluated the clinical usefulness of plasma matrix metalloproteinase-7 (MMP-7) as a diagnostic and prognostic biomarker in patients with renal cell carcinoma (RCC). MMP-7 was quantified in plasma of 50 healthy subjects and 97 RCC patients using a Fluorokine MultiAnalyte Profiling assay. RCC patients were stratified into the following groups: without metastases (N0M0; n = 39), with lymph nodes (N1M0; n = 13), and with distant metastases (M1; n = 45). Diagnostic performance of MMP-7 was analyzed by the receiver operating characteristics (ROC) curve. Kaplan-Meier analysis and the Cox regression model were used to estimate the impact of MMP-7 on the cancer-specific survival outcome of RCC patients. MMP-7 was significantly higher in both metastatic groups N1M0 and M1 (medians, 3.82 and 3.34 microg/L) compared to N0M0 group or controls (medians, 1.85 and 1.64 microg/L; all P < 0.001). In ROC analysis, the area under the ROC curve of MMP-7 was 0.80 in the detection of metastases in RCC (P < 0.0001). In the Kaplan-Meier analysis, patients with MMP-7 above the 95th percentile of controls showed less favorable survival rates compared to those with normal MMP-7 (log-rank test, 15.7; P < 0.0001). High MMP-7 was associated with cancer-related mortality estimated by univariate Cox regression (risk ratio, 4.34, 95% CI, 1.12-10.6; P = 0.032). The multivariate Cox regression model determined MMP-7 (risk ratio, 2.70, 95% CI, 1.39-5.24; P = 0.003) and metastases (risk ratio, 5.81, 95% CI, 2.77-12.2; P < 0.0001) as independent determinants of cancer-related survival outcomes. In conclusion, increased plasma MMP-7 could be related to metastatic disease and poor prognosis in patients with RCC.

The inhibition of matrix metalloproteinase activity in chronic wounds by a polyacrylate superabsorber

Excessive matrix metalloproteinase (MMP) levels have been observed in wound fluid of impaired healing wounds. This is thought to interfere with granulation tissue formation as newly formed extracellular matrix and cytokines are degraded and the wound becomes deadlocked, unable to progress to the next healing stages. In the cleansing phase, associated with high MMP activity levels, hydroactive wound dressings containing polyacrylate superabsorber particles are particularly effective. We tested whether these particles can block MMP activity in wound fluid obtained from chronic venous leg ulcers. Polyacrylate superabsorber particles inhibited MMP activity by more than 87% in a fluorogenic peptide substrate assay. Further analysis revealed two underlying molecular mechanisms. First, experiments showed direct binding of MMPs to the particles. Secondly, polyacrylate superabsorber particles can bind Ca 2+ and Zn 2+ ions competing with MMPs for divalent ions required for enzymatic activity. Furthermore, we provide the first evidence in vivo that MMPs bind effectively to polyacrylate superabsorber particles within the hostile environment of chronic wounds. We conclude that polyacrylate superabsorber particles can rescue the highly proteolytic microenvironment of non-healing wounds from MMP activity so that more conductive conditions allow healing to proceed.

Induction of MMP-1, MMP-3 and TIMP-1 in normal dermal fibroblasts by chronic venous leg ulcer wound fluid*

In the wound bed of chronic venous leg ulcers, an imbalance of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) may cause excessive proteolysis and impair wound granulation. Soluble mediators in the wound environment may be responsible for this imbalance. The in vitro effect of wound fluid from venous leg ulcers on dermal fibroblast production of MMP-1, MMP-3 and TIMP-1 was compared with the effect of acute wound fluid from two different sources: fluid from post-mastectomy axillary drains and fluid from skin graft donor sites. Significantly higher MMP-1 and MMP-3 levels were induced by chronic venous leg ulcer wound fluid compared with both types of acute wound fluid (P < 0.005). Chronic venous ulcer wound fluid reduced TIMP-1 protein levels significantly more than acute graft fluid (P < 0.05). Venous ulcer wound fluid significantly increased MMP-1 and MMP-3 production in dermal fibroblasts and reduced TIMP-1 production, confirming that mediators in the leg ulcer microenvironment can potentially induce excessive proteolysis in the ulcer dermis by altering the balance between MMPs and TIMPs. Inflammatory mediators including interleukin-1beta and tumour necrosis factor-alpha can induce these MMPs. Further work is required to confirm the factors responsible for the induction of a high MMP and low TIMP profile in fibroblasts by venous ulcer wound fluid.

Congenic expression of tissue inhibitor of metalloproteinase in Dahl-salt sensitive hypertensive rats is associated with reduced LV hypertrophy

Although congenic translocation of a segment from chromosome 10 from Lewis rat, containing an extracellular proteinase inhibitor gene, decreased blood pressure in Dahl-salt sensitive (DSS) rats, the relationship between the levels of matrix metalloproteinase (MMP), tissue inhibitor of metalloproteinase (TIMP), and cardiac function was unclear. In this study we investigated the cardiac effects of congenic translocation of a segment from chromosome 10 from Lewis rat, containing an extracellular proteinase inhibitor gene, in Dahl-salt sensitive rats. To test the hypothesis that left ventricular (LV) hypertrophy in DSS rats was due to high MMP and low TIMP levels and the decrease in blood pressure in congenic rats was associated with increase in proteinase inhibitor expression, cardiac function and levels of MMP and TIMP were determined in 16 weeks male DSS (D), Lewis (L) and congenic (CL-10) rats. Cardiac function was assessed by electrocardiography, echocardiography and a Millar catheter in LV cavity. LV MMP and TIMP levels were measured by Q-RT-PCR and Western blot analyses. In L, D and CL-10 rats, heart weight/body weight (g/g) were 3.73 ± 0.06, 4.45 ± 0.04 and 3.35 ± 0.05 × 10−3, respectively, suggesting significant (p < 0.05) LV hypertrophy (LVH) in D group. The ST duration was longer in D group compared with L group, suggesting coronary vasospasm, but normalized in CL-10 rats. The fractional shortening and ejection fraction were decreased in D group as compared with L group, but normalized in CL-10 groups. LV diameter was increased in D group as compared to L group, but normalized in CL-10 groups. The levels of MMP-9 were higher and TIMP were lower in D as compared to L groups, but normalized in CL-10 rats. Compared with control non-congenic Dahl rats, congenic rats exhibited lower blood pressure, amelioration of LV remodelling and dysfunction, as well as coronary abnormalities. In addition, congenic animals exhibited reduced myocardial expression of MMP-9, but increased expression of MMP-2 and TIMP-4 compared to non congenic animals. We concluded that the congenic transfer of TIMP ameliorated LV hypertrophy and cardiac dysfunction.