Circulating beta-chemokines and matrix metalloproteinase-9/tissue inhibitor of metalloproteinase-1 system in hemodialyzed patients--role of oxidative stress

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), beta-chemokines, increased oxidative stress (SOX) and inflammation have been implicated as important factors in atherosclerosis and vascular remodeling. We hypothesized the possible roles of beta-chemokines [monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory proteins (MIP-1alpha, MIP-1beta) and regulated upon activation, normal T-cell expressed and secreted (RANTES)] as regulators of the metabolism of the vascular extracellular matrix in conditions of increased SOX in hemodialysis (HD) patients. We compared pre-dialysis levels of MMP-9/TIMP-1 system, beta-chemokines, Cu/Zn superoxide dismutase (Cu/Zn SOD) as a marker of SOX and C-reactive protein (CRP) as a marker of inflammation in HD patients with and without cardiovascular disease (CVD) to those of controls. HD patients, particularly those with CVD, showed a significant increase in values of Cu/Zn SOD, CRP, TIMP-1, TIMP-1/MMP-9 ratio, MCP-1 and MIP-1beta, whereas RANTES levels were lower than in the controls. The levels of MIP-1alpha as well as MMP-9 in all HD groups were similar to the controls. The positive correlations were observed between the MMP-9/TIMP-1 system and beta-chemokines, SOX and inflammation in whole HD group and in the subgroup with CVD. Multivariate analysis showed that the duration of dialysis followed by Cu/Zn SOD, MIP-1alpha and beta levels were the significant positive predictors of TIMP-1. In conclusion, our data show that MMP-9/TIMP-1 system and beta-chemokines could cooperate in conditions of elevated SOX, which ultimately predisposes hemodialysis patients to accelerated atherosclerosis.     

Plasma transforming growth factor beta1, metalloproteinase-1 and tissue inhibitor of metalloproteinases-1 in acute viral hepatitis type B

AIM: Antiproliferative, pro-apoptotic and immunosuppressive activity effects suggest crucial role of transforming growth factor (TGF)-beta1, metalloproteinase (MMP)-1 and its tissue inhibitor (TIMP)-1 in the pathogenesis of acute liver injury that in some patients precede development of chronic liver diseases and fibrogenesis. The aim of this study was to evaluate effect of acute HBV infection on plasma TGF-beta1, MMP-1 and TIMP-1 levels. METHODS: TGF-beta1, MMP-1 and TIMP-1 plasma concentrations were measured with an enzyme immunoassay in 39 patients with acute viral hepatitis type B. Baseline measurement was performed within the first week of jaundice and then weekly up to the fourth week of the disease. Results were compared to baseline and normal values and to liver function tests. RESULTS: Plasma concentrations of TGF-beta1, TIMP-1 and MMP-1 were significantly elevated in the first week of acute viral B hepatitis in comparison to normal. Analysis of individual values demonstrated significant positive correlation between plasma concentrations of TGF-beta1 and TIMP-1. There was no correlation between MMP-1 and TGF-beta1 or TIMP-1. Significant correlation was demonstrated between both TGF-beta1 and ALT or AST as well as between TIMP-1 and ALT, AST or bilirubin. Elevated baseline levels of both TGF-beta1 and TIMP-1 decreased gradually in consecutive weeks of the disease. TGF-beta1 but not TIMP-1 plasma concentrations were significantly lower in 3rd and 4th week than baseline values. MMP-1 concentration remained on baseline level in the 2nd week of the disease. However in the 3rd week its values increased suddenly but the significant difference in comparison to baseline was observed only in 4th week. CONCLUSIONS: These results indicate important role of TGF-beta1, TIMP-1 and MMP-1 in acute viral hepatitis, that seems to be connected first of all with hepatocytes damage. Their role in extracellular matrix metabolism during acute liver injury needs further evaluation.     

Elevated matrix metalloproteinase-9 in patients with systemic sclerosis

Matrix metalloproteinase-9 (MMP-9) has been implicated in the pathogenesis of cancer, autoimmune disease, and various pathologic conditions characterized by excessive fibrosis. In this study, we investigated the expression of MMP-9 and its clinical significance in systemic sclerosis (SSc). The patients (n = 42) with SSc had higher concentrations of MMP-9 and of tissue inhibitor of metalloproteinase-1 (TIMP-1) and a higher ratio of MMP-9 to TIMP-1 in sera than healthy controls (n = 32). Serum MMP-9 concentrations were significantly higher in the diffuse type (n = 23) than the limited type of SSc (n = 19). Serum concentrations of MMP-9 correlated well with the degree of skin involvement, as determined by the Rodnan score and with serum concentrations of transforming growth factor β. Moreover, dermal fibroblasts from patients with SSc produced more MMP-9 than those from healthy controls when they were stimulated with IL-1β, tumor necrosis factor α, or transforming growth factor β. Such an increase in MMP-9 production was partially blocked by treatment with cyclosporin A. In summary, the serum MMP-9 concentrations were elevated in SSc patients and correlated well with skin scores. The increased MMP-9 concentrations may be attributable to overproduction by dermal fibroblasts in SSc. These findings suggest that the enhanced production of MMP-9 may contribute to fibrogenic remodeling during the progression of skin sclerosis in SSc.     

Elevated matrix metalloproteinase-9 in patients with systemic sclerosis

Matrix metalloproteinase-9 (MMP-9) has been implicated in the pathogenesis of cancer, autoimmune disease, and various pathologic conditions characterized by excessive fibrosis. In this study, we investigated the expression of MMP-9 and its clinical significance in systemic sclerosis (SSc). The patients (n = 42) with SSc had higher concentrations of MMP-9 and of tissue inhibitor of metalloproteinase-1 (TIMP-1) and a higher ratio of MMP-9 to TIMP-1 in sera than healthy controls (n = 32). Serum MMP-9 concentrations were significantly higher in the diffuse type (n = 23) than the limited type of SSc (n = 19). Serum concentrations of MMP-9 correlated well with the degree of skin involvement, as determined by the Rodnan score and with serum concentrations of transforming growth factor beta. Moreover, dermal fibroblasts from patients with SSc produced more MMP-9 than those from healthy controls when they were stimulated with IL-1beta, tumor necrosis factor alpha, or transforming growth factor beta. Such an increase in MMP-9 production was partially blocked by treatment with cyclosporin A. In summary, the serum MMP-9 concentrations were elevated in SSc patients and correlated well with skin scores. The increased MMP-9 concentrations may be attributable to overproduction by dermal fibroblasts in SSc. These findings suggest that the enhanced production of MMP-9 may contribute to fibrogenic remodeling during the progression of skin sclerosis in SSc.     

Circulating proangiogenic molecules PIGF, SDF-1 and sVCAM-1 in patients with systemic lupus erythematosus

Serum concentrations of three angiogenic cytokines: vascular endothelial growth factor (VEGF), stromal cell-derived factor-1 (SDF-1) and placental growth factor (PIGF) and soluble vascular cell adhesion molecule 1 (sVCAM-1), were investigated in the serum of 61 patients with systemic lupus erythematosus (SLE) and 20 healthy subjects. The possible association between serum levels of these proteins and SLE activity, as well as correlation between the concentrations of cytokines were also analysed. All of these factors were detectable in all SLE patients and the healthy control group. The median concentration of VEGF was higher in active SLE (386 pg/mL) than in inactive disease (327 pg/mL) or in the control group (212 pg/mL, p<0.004). The median serum level of SDF-1 was higher in SLE patients (1,814 pg/mL) than in the control group (1,507 pg/mL, p<0.02). The median concentration of PIGF was higher (14 pg/mL) in SLE patients than in the control group (12 pg/mL, p=0.03), and particularly in active disease (17 pg/mL) as compared to the inactive phase (13 pg/mL, p=0.01). The correlations between the levels of cytokines examined and clinical features, laboratory abnormalities and the type of treatment were also analysed. We found a positive correlation between serum concentrations of PIGF and SLE activity according to SLAM score (p=0.33, p=0.13).     

Circulating TCR gammadelta cells in the patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a disorder with a wide range of immunological abnormalities. The results of the studies undertaken in the last decade indicated that SLE pathogenesis was mainly connected with the breakdown of the activation control of B and T cells, generating humoral or cell-mediated responses against several self-antigens of affected cells. The last studies demonstrate that the role of gammadelta T lymphocytes in autoimmune diseases can be especially important. Flow cytometry techniques were used to investigate the number and percentage of TCR gammadelta T cells and their most frequent subtypes in peripheral blood of 32 patients with SLE and 16 healthy volunteers. We also correlated TCR gammadelta cells number with the level of T CD3+, T CD4+, T CD8+, and NK (CD16) cells (cytometric measurements) and SLE activity (on the basis of clinical investigations). Our studies were preliminary attempts to evaluate the role of that minor T cell subpopulation in SLE. Absolute numbers of cells expressing gammadelta TCR in most SLE blood specimens were significantly lower than in the control group (P<0.006). However, since the level of total T cell population was also decreased in the case of SLE, the mean values of the percentage gammadelta T cells of pan T lymphocytes were almost the same in both analysed populations (7.1% vs 6.3%, respectively). In contrast to Vdelta2+ and Vgamma9+ subtypes of pan gammadelta T cells, Vdelta3+ T cells number was higher in SLE patients (20 x 10 cells/microl) than in healthy control group (2 x 2 cells/microl) (P=0.001). However, we found no differences between the numbers of pan gammadelta T lymphocytes and studied their subtypes in the patients with active and inactive disease. These cell subpopulations were doubled in the treated patients with immunosuppressive agents in comparison with untreated ones; however, data were not statistically significant. Our study indicated that Vdelta3+ subtype of gammadelta T cells seems to be involved in SLE pathogenesis; however, we accept the idea that the autoimmunity does not develop from a single abnormality, but rather from a number of different events.     

Anti-C1q antibodies antedate patent active glomerulonephritis in patients with systemic lupus erythematosus

Introduction

Autoantibodies against C1q correlate with lupus nephritis. We compared titers of anti-C1q and anti-dsDNA in 70 systemic lupus erythematosus patients with (n = 15) or without (n = 55) subsequent biopsy-proven lupus nephritis.

Methods

The 15 patients with subsequent lupus nephritis had anti-C1q assays during clinical flares (mean Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), 10.0 ± 4.7; range, 3 to 22) before the diagnosis of lupus nephritis (median, 24 months; range 3 to 192). Among the 55 others, 33 patients had active lupus (mean SLEDAI, 10.3 ± 6.2; range, 4 to 30) without renal disease during follow-up (median 13 years; range 2 to 17 years) and 22 had inactive lupus (mean SLEDAI, 0; range, 0 to 3).

Results

Anti-C1q titers were elevated in 15/15 (100%) patients who subsequently developed nephritis (class IV, n = 14; class V, n = 1) and in 15/33 (45%) patients without renal disease (P < 0.001). The median anti-C1q titer differed significantly between the groups (P = 0.003). Anti-C1q titers were persistently positive at the time of glomerulonephritis diagnosis in 70% (7/10) of patients, with no difference in titers compared with pre-nephritis values (median, 147 U/ml; interquartile range (IQR), 69 to 213 versus 116 U/ml; 50 to 284, respectively). Titers decreased after 6 months'' treatment with immunosuppressive drugs and corticosteroids (median, 76 U/ml; IQR, 33 to 106) but remained above normal in 6/8 (75%) patients. Anti-dsDNA antibodies were increased in 14/15 (93.3%) patients with subsequent nephritis and 24/33 (72.7%) patients without nephritis (P = ns). Anti-C1q did not correlate with anti-dsDNA or the SLEDAI in either group.

Conclusions

Anti-C1q elevation had 50% positive predictive value (15/30) and 100% (18/18) negative predictive value for subsequent class IV or V lupus nephritis.     

Interleukin 15 stimulates production of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 by human peripheral blood mononuclear cells

In peripheral blood mononuclear cells (PBMC), matrix metalloproteinase (MMP)-9 mediates the extravasation of immune cells and may be involved in tissue destruction during inflammation. We investigated the effect of the pro-inflammatory cytokines interleukin (IL-)12 and 15 on the secretion of MMP-9 in PBMC. IL-15, but not IL-12, induces MMP-9 in PBMC and in T cells. Moreover, the combination of IL-15 and IL-2 had an additive effect. In contrast, both IL-12 and IL-15 induced the release of tissue inhibitor of metalloproteinases (TIMP)-1. IL-15 led to a dose-dependent increase of the MMP-9/TIMP-1 ratio as a measure for increased proteolytic capacity. We conclude that IL-15 mediates its effects in inflammation in part through MMP-9.     

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.     

Interferon inhibitor in the blood of patients with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) patients at advanced stages of the disease have an interferon inhibitor in the blood circulation. This inhibitor can block antiviral activity of all three types of human interferons and can significantly reduce the synthesis of interferon alpha by the treated lymphocytes obtained from normal healthy individuals. Available evidence suggests that inhibitor activity is neither because of the antibody to interferon nor due to high level of protease-like activity in the plasma. The inhibitor has also been shown to be effective in eliminating the interferon-mediated enhancement of natural killer cell activity. Interferon inhibitory activity was not detected in any of the sera taken from normal healthy individuals. Identification and characterization of interferon inhibitor has direct bearing upon effective utilization of interferons in the clinic.     

Tissue plasminogen activator inhibitor in patients with systemic lupus erythematosus and thrombosis.

OBJECTIVE--To examine the relations among tissue plasminogen activator antigen, plasminogen activator inhibitor, the lupus anticoagulant, and anticardiolipin antibodies in patients with systemic lupus erythematosus. DESIGN--Prospective study of blood samples (a) from selected patients with systemic lupus erythematosus whose disease was and was not complicated by a history of thrombosis or recurrent abortions, or both, and (b) from a series of healthy controls with a similar age and sex distribution. SETTING--University based medical clinic. SUBJECTS--23 Patients with definite systemic lupus erythematosus (American Rheumatism Association criteria), of whom 11 (eight women) aged 26-51 had a history of thrombosis or recurrent abortions, or both, and 12 (10 women) aged 23-53 had no such history. 15 Healthy subjects (10 women) aged 25-58 served as controls. MAIN OUTCOME MEASURES--Tissue plasminogen activator concentrations, plasminogen activator inhibitor activities, detection of the lupus anticoagulant, and values of anticardiolipin antibodies in the two groups of patients and in the patients with a history of thrombosis or abortions compared with controls. Other measurements included concentrations of proteins that are known to change during the acute phase of systemic lupus erythematosus--namely, fibrinogen, C3 and C4, and C reactive protein. RESULTS--Patients with a history of thrombosis or abortions, or both, had significantly higher values of tissue plasminogen activator and plasminogen activator inhibitor than patients with no such history. A significant correlation between tissue plasminogen activator and plasminogen activator inhibitor (r = 0.80) was found only in the patients with a history of complications of their disease. The lupus anticoagulant was detected in six of the 11 patients with a history of thrombosis or abortions when tested by measuring the activated partial thromboplastin time but was found in all 11 patients when tested by measuring the diluted activated partial thromboplastin time. Nine of these 11 patients had raised values of anticardiolipin antibodies. The findings showed no relation to the activity of the disease. CONCLUSIONS--A significant correlation between tissue plasminogen activator concentrations and plasminogen activator inhibitor activities was found only in patients whose systemic lupus erythematosus was complicated by a history of thrombosis or recurrent abortions. The findings show that these patients have raised plasminogen activator inhibitor activities, and the frequent association between these raised activities and the presence of the lupus anticoagulant suggests that the two may be linked.     

Assessment of the biological variation of plasma tissue inhibitor of metalloproteinases-1

BACKGROUND: Tissue inhibitor of metalloproteinases-1 (TIMP-1) measurements in plasma may be useful for the early detection and prognosis of colorectal cancer (CRC). Data on analytical performance and normal intra- and interindividual biological variation are required in order to interpret the utility of TIMP-1 in CRC. The aim of this study was to establish the biological and analytical variation of plasma TIMP-1 in volunteers. MATERIAL AND METHODS: Three separate studies were undertaken. 1: Plasma was collected from 23 volunteers 6 times within a 3-week period, first in September 2004 (round [R] 1), then repeated in May 2005 (R2) and May 2006 (R3) in the same group of individuals. TIMP-1 levels were determined by the MAC15 ELISA assay and with the Abbott ARCHITECT i2000 Immunoanalyzer. 2: Circadian variation was evaluated in plasma collected 7 times within a 24-hour period (n=16). 3: Effects of physical exercise were evaluated in plasma collected before and after bicycling (n=14). In studies 2 and 3 TIMP-1 levels were determined with the MAC15 ELISA assay only. RESULTS: A significant correlation between TIMP-1 MAC15 and ARCHITECT i2000 was shown (rs=0.78, p<0.002), with consistently higher levels being detected by the ARCHITECT i2000. Median levels of TIMP-1 (ARCHITECT) at 8 a.m. in each round were 74.9 ng/mL (range 65.7-89.9) (R1), 87.3 ng/mL (range 72.7-127.9) (R2), and 81.9 ng/mL (range 66.8-113.6) (R3). The within-subject variation was 10.7%, the variation between rounds was 7.4%, and the intraclass correlation was 46.2%. Comparison between the 3 rounds and time of collection showed that TIMP-1 values decreased by 11% after storage for more than 16 months (p=0.0002). A systematic circadian variation in plasma TIMP-1 levels was not observed (p=0.17). No significant variation of plasma TIMP-1 was found in relation to physical exercise (p=0.92 [global test]). CONCLUSION: Levels of plasma TIMP-1 in volunteers show limited circadian, day-to-day, week-to-week and season-to-season variation. In addition, physical exercise has no impact on plasma TIMP-1 levels. Possible storage-dependent decreases in plasma TIMP-1 levels warrant further investigation.     

Inactivation of tissue inhibitor of metalloproteinases-1 (TIMP-1) by Porphyromonas gingivalis

In response to periodontal inflammation, host cells release matrix metalloproteinases (MMPs) that contribute to periodontal tissue breakdown unless the tissue inhibitors of metalloproteinases (TIMPs) neutralize their activity. In this study, the capacity of Porphyromonas gingivalis to inactivate TIMP-1 was investigated. Proteolytic digestion of TIMP-1 was monitored by SDS-PAGE and Western immunoblotting. Planktonic cells and biofilms of P. gingivalis degraded TIMP-1 with production of several lower molecular mass fragments. Incorporation of human serum in the assay mixture had no effect on the degradation of TIMP-1 by P. gingivalis, whereas a cysteine proteinase inhibitor caused a complete inhibition. Using a fluorogenic assay, it was found that TIMP-1 treated with P. gingivalis lost its capacity to inhibit MMP-9 activity. This study revealed the potential of P. gingivalis to inactivate TIMP-1 through proteolytic degradation. This phenomenon may contribute to increasing significantly the level of active MMPs in affected periodontal sites and subsequently favor tissue destruction.     

Constraining specificity in the N-domain of tissue inhibitor of metalloproteinases-1; gelatinase-selective inhibitors

The tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of the matrix metalloproteinases (MMPs). Since unregulated MMP activities are linked to arthritis, cancer, and atherosclerosis, TIMP variants that are selective inhibitors of disease-related MMPs have potential therapeutic value. The structures of TIMP/MMP complexes reveal that most interactions with the MMP involve the N-terminal pentapeptide of TIMP and the C-D beta-strand connector which occupy the primed and unprimed regions of the active site. The loop between beta-strands A and B forms a secondary interaction site for some MMPs, ranging from multiple contacts in the TIMP-2/membrane type-1 (MT1)-MMP complex to none in the TIMP-1/MMP-1 complex. TIMP-1 and its inhibitory domain, N-TIMP-1, are weak inhibitors of MT1-MMP; inhibition is not improved by grafting the longer AB loop from TIMP-2 into N-TIMP-1, but this change impairs binding to MMP-3 and MMP-7. Mutational studies with N-TIMP-1 suggest that its weak inhibition of MT1-MMP, as compared to other N-TIMPs, arises from multiple (>3) sequence differences in the interaction site. Substitutions for Thr2 of N-TIMP-1 strongly influence MMP selectivity; Arg and Gly, that generally reduce MMP affinity, have less effect on binding to MMP-9. When the Arg mutation is added to the N-TIMP-1(AB2) mutant, it produces a gelatinase-specific inhibitor with Ki values of 2.8 and 0.4 nM for MMP-2 and -9, respectively. Interestingly, the Gly mutant has a Ki of 2.1 nM for MMP-9 and >40 muM for MMP-2, indicating that engineered TIMPs can discriminate between MMPs in the same subfamily.     

Tyrosine 36 plays a critical role in the interaction of the AB loop of tissue inhibitor of metalloproteinases-2 with matrix metalloproteinase-14

The tissue inhibitor of metalloproteinases-2 (TIMP-2) is potentially an important inhibitor of all known matrix metalloproteinases (MMPs). However, it has been shown to undergo specific interactions with both MMP-2 (gelatinase A) and MMP-14 (MT1-MMP), and it has been proposed that these three proteins function as a cell surface-based activation cascade for matrix metalloproteinases and as a focus of proteolytic activity. In this study, we have carried out mutagenesis and kinetic analyses to examine the unique interactions between the AB loop of TIMP-2 and MMP-14. The results demonstrate that the major binding contribution of the AB loop is due solely to residue Tyr-36 at the tip of the hairpin. From this work, we propose that TIMP-2 may be engineered to abrogate MMP-14 binding, whereas its binding properties for other MMPs, including MMP-2, are maintained. Mutants of TIMP-2 with more directed specificity may be of use in gene therapeutic approaches to human disease.     

Matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-3 are key regulators of extracellular matrix degradation by mouse embryos

Embryo implantation in humans and rodents is a highly invasive yet tightly controlled process involving extracellular matrix (ECM) degradation. Matrix metalloproteinase 9 (MMP-9) has been implicated as the major facilitator of this ECM degradation. MMP-9 is expressed by the embryo's trophoblast cells, whereas tissue inhibitor of metalloproteinases 3 (TIMP-3) is expressed by the maternal uterine cells immediately adjacent to the trophoblast. We examined the functional roles of MMP-9 and TIMP-3 during in vitro ECM degradation by mouse embryos. Blastocysts were treated with either MMP-9 antisense or sense oligonucleotides and incubated on an ECM gel. The extent of ECM degradation exhibited by the blastocysts due to proteinase secretion was quantified. Embryos exposed to MMP-9 antisense oligonucleotides exhibited reduced ECM-degrading activity as compared with controls, and this reduced activity was correlated with the level of MMP-9 secreted by the embryos. The functional role of TIMP-3 was then examined by incubating blastocysts on an ECM gel that had been impregnated with various amounts of TIMP-3. In a dose-dependent manner, increases in TIMP-3 resulted in a reduction in ECM degradation and were correlated with diminished MMP-9 activity. These results provide important functional evidence that in vitro ECM degradation is regulated by embryo-derived MMP-9 and ECM-derived TIMP-3.