Association between Gene Polymorphisms and SNP-SNP Interactions of the Matrix Metalloproteinase 2 Signaling Pathway and the Risk of Vascular Senescence

Objective This study aimed to explore the association of single nucleotide polymorphisms(SNP)in the matrix metalloproteinase 2(MMP-2)signaling pathway and the risk of vascular senescence(VS).Methods In this cross-sectional study,between May and November 2022,peripheral venous blood of151 VS patients(case group)and 233 volunteers(control group)were collected.Fourteen SNPs were identified in five genes encoding the components of the MMP-2 signaling pathway,assessed through carotid-femoral pulse wave velocity(cf PWV),and analyzed using multivariate logistic regression.The multigene influence on the risk of VS was assessed using multifactor dimensionality reduction(MDR)and generalized multifactor dimensionality regression(GMDR)modeling.Results Within the multivariate logistic regression models,four SNPs were screened to have significant associations with VS:chemokine(C-C motif)ligand 2(CCL2)rs4586,MMP2 rs14070,MMP2rs7201,and MMP2 rs1053605.Carriers of the T/C genotype of MMP2 rs14070 had a 2.17-fold increased risk of developing VS compared with those of the C/C genotype,and those of the T/T genotype had a19.375-fold increased risk.CCL2 rs4586 and MMP-2 rs14070 exhibited the most significant interactions.Conclusion CCL2 rs4586,MMP-2 rs14070,MMP-2 rs7201,and MMP-2 rs1053605 polymorphisms were significantly associated with the risk of VS.

Placenta-derived mesenchymal stem cells attenuate secondary brain injury after controlled cortical impact in rats by inhibiting matrix metalloproteinases

Background:As a form of biological therapy,placenta-derived mesenchymal stem cells(PDMSCs)exhibit considerable promise in addressing the complex pathological processes of traumaticbrain injury(TBI)due to their multi-target and multi-pathway mode of action.Material&Methods:This study investigates the protective mechanisms and benefits of PDMSCs in mitigating the effects of controlled cortical impact(CCI)in rats and glutamate-induced oxidative stress injury in HT22 cells in vitro.Our primary objective is to provide evidence supporting the clinical application of PDMSCs.Results:In the in vivo arm of our investigation,we observed a swift elevation of matrix metalloproteinase-9(MMP-9)in the proximal cortex of injured brain tissues after CCI.PDMSCs,distinguished by their heightened expression of metalloproteinase tissue inhibitors-1 and-2(TIMP-1 and TIMP-2):were intravenously administered via the caudal vein.This intervention yielded significant reductions in the permeability of the blood-brain barrier(BBB):the extent of brain edema,the levels of inflammatory cytokines IL-1βand TNF-αin damaged brain tissue,and the activation status of microglia in CCI-afflicted rats.In the realm of in vitro experiments,PDMSC-conditioned media demonstrated substantial reductions in mortality rates and cleaved caspase-3 levels in glutamate-induced HT22 cells compared with conventional media.Notably,this advantage was negated upon the introduction of neutralizing antibodies targeting TIMP-1 and TIMP-2.Conclusion:Collectively,our findings underscore the potential of PDMSCs in alleviating oxidative stress injury and secondary brain injury in the pathological process of TBI.

Diagnostic value of matrix metalloproteinases 2, 7 and 9 in urine for early detection of colorectal cancer

BACKGROUND A noninvasive biomarker with high diagnostic performance is urgently needed for the early diagnosis of colorectal cancer(CRC).AIM To evaluate the diagnostic value of matrix metalloproteinases(MMPs)2,7 and 9 in urine for CRC.METHODS Of 59 healthy controls,47 patients with colon polyps and 82 patients with CRC were included in this study.Carcinoembryonic antigen(CEA)in serum and MMP2,MMP7,and MMP9 in urine were detected.The combined diagnostic model of the indicators was established by binary logistic regression.The receiver operating characteristic curve(ROC)of the subjects was used to evaluate the independent and combined diagnostic value of the indicators.RESULTS The MMP2,MMP7,MMP9,and CEA levels in the CRC group differed significantly from levels in the healthy controls(P<0.05).The levels of MMP7,MMP9,and CEA also differed significantly between the CRC group and the colon polyps group(P<0.05).The area under the curve(AUC)distinguishing between the healthy control and the CRC patients using the joint model with CEA,MMP2,MMP7 and MMP9 was 0.977,and the sensitivity and specificity were 95.10%and 91.50%,respectively.For early-stage CRC,the AUC was 0.975,and the sensitivity and specificity were 94.30%and 98.30%,respectively.For advanced stage CRC,the AUC was 0.979,and the sensitivity and specificity were 95.70%and 91.50%,respectively.Using CEA,MMP7 and MMP9 to jointly established a model distinguishing the colorectal polyp group from the CRC group,the AUC was 0.849,and the sensitivity and specificity were 84.10%and 70.20%,respectively.For early-stage CRC,the AUC was 0.818,and the sensitivity and specificity were 76.30%and 72.30%,respectively.For advanced stage CRC,the AUC was 0.875,and the sensitivity and specificity were 81.80%and 72.30%,respectively.CONCLUSION MMP2,MMP7 and MMP 9 may exhibit diagnostic value for the early detection of CRC and may serve as auxiliary diagnostic markers for CRC.

Imbalance of matrix metalloproteinase-9 and matrix metalloproteinase tissue inhibitor-1 may contribute to hemorrhage in cerebellar arteriovenous malformations

In this study, we determined the expression levels of matrix metalloproteinase-2 and -9 and matrix metalloproteinase tissue inhibitor-1 and -2 in brain tissues and blood plasma of patients undergoing surgery for cerebellar arteriovenous malformations or primary epilepsy （control group）. Immunohistochemistry and enzyme-linked immunosorbent assay revealed that the expression of matrix metalloproteinase-9 and matrix metalloproteinase tissue inhibitor-1 was significantly higher in patients with cerebellar arteriovenous malformations than in patients with primary epilepsy. The ratio of matrix metalloproteinase-9 to matrix metalloproteinase tissue inhibitor-1 was significantly higher in patients with hemorrhagic cerebellar arteriovenous malformations compared with those with non-hemorrhagic malformations. Matrix metalloproteinase-2 and matrix metalloproteinase tissue inhibitor-2 levels were not significantly changed. These findings indicate that an imbalance of matrix metalloproteinase-9 and matrix metalloproteinase tissue inhibitor-I, resulting in a relative overabundance of matrix metalloproteinase-9, might be the underlying mechanism of hemorrhage of cerebellar arteriovenous malformations.

Effects of hypoxia,hyperoxia on the regulation of expression and activity of matrix metalloproteinase-2 in hepatic stellate cells

AIM To study the effects of hypoxia, hyperoxia on the regulation of expression and activity of matrix metalloproteinase-2 (MMP-2) in hepatic stellate cells ( HSC).``METHODS The expressions of MMP-2, tissue inhibitor of mjatrix metalloproteinese-2 ( TIMP-2 ) and membrane type matrix metalloproteiness-l (MT1-MMP) in cultured rat HSC were detected by immunocytochemistry (ICC) and in situ hybridization (ISH). The contents of MMP-2 and TIMP-2 in culture supernatant were detected with ELISA and the activity of MMP-2 in supematant was revealed by zymography.``RESULTS In the situation of hypoxia for 12 h, the expression of MMP-2 protein wss enhenced (hypoxiagroup positive indexes: 5.7 ± 2.0, n = 10; control: 3.2 ±1 .0. n -- 7; P＜0.05). while TIMP-2 protein wss decreased in HSC ( hypoxia group positive indexes: 2.5 ± 0.7, n =10: control: 3.6 ± 1.0, n = 7; P＜O.05), and the activity ( total A) of MMP-2 in supematant declined obviously (hypoxia group: 7.334 ± 1.922, n = 9; control: 17.277 ±7.424. n= 11; P＜0.01). Compared the varied duration of hypoxia, the changes of expressions including mRNA and protein level as well as activity of MMP-2 were most notable in 6 h group. The highest value (Ahypoxia-Acontrol) ofthe protein and the most intense signal of mRNA were in the period of hypoxia for 6 h, along with the lowest activity of MMP-2. In the situation of hyperoxia for 12 h,the contonts (A450) of MMP-2 and TIMP-2 in supernatant were both higher then those in the control, especially the TIMP-2 (hyperoxia group: 0.0499 _+ 0.0144, n = 16;control: 0.0219 ± 0.0098, n = 14; P＜0.01), and so was the activity of MMP-2 (hyperoxia group: 5.252 _+ 0.771,n: 14; control: 4.304 +_ 1 .083, n = 12; P＜0.05), and the expression of MT1-MMP was increased.``CONCLUSION HSC Js sensitive to the oxygen, hypoxia enhances the expression of MMP-2 and the effect is more marked at the early stage; hyperoxia mainly raises the activity of MMP-2.

Matrix metalloproteinases and gastrointestinal cancers: Impacts of dietary antioxidants

The process of carcinogenesis is tightly regulated by antioxidant enzymes and matrix degrading enzymes, namely, matrix metalloproteinases(MMPs). Degradation of extracellular matrix(ECM) proteins like collagen, proteoglycan, laminin, elastin and fibronectin is considered to be the prerequisite for tumor invasion and metastasis. MMPs can degrade essentially all of the ECM components and, most MMPs also substantially contribute to angiogenesis, differentiation, proliferation and apoptosis. Hence, MMPs are important regulators of tumor growth both at the primary site and in distant metastases; thus the enzymes are considered as important targets for cancer therapy. The implications of MMPs in cancers are no longer mysterious; however, the mechanism of action is yet to be explained. Herein, our major interest is to clarify how MMPs are tied up with gastrointestinal cancers. Gastrointestinal cancer is a variety of cancer types, including the cancers of gastrointestinal tract and organs, i.e., esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus. The activity of MMPs is regulated by its endogenous inhibitor tissue inhibitor of metallopro-teinase(TIMP) which bind MMPs with a 1:1 stoichiometry. In addition, RECK(reversion including cysteinerich protein with kazal motifs) is a membrane bound glycoprotein that inhibits MMP-2,-9 and-14. Moreover, α2-macroglobulin mediates the uptake of several MMPs thereby inhibit their activity. Cancerous conditions increase intrinsic reactive oxygen species(ROS) through mitochondrial dysfunction leading to altered protease/anti-protease balance. ROS, an index of oxidative stress is also involved in tumorigenesis by activation of different MAP kinase pathways including MMP induction. Oxidative stress is involved in cancer by changing the activity and expression of regulatory proteins especially MMPs. Epidemiological studies have shown that high intake of fruits that rich in antioxidants is associated with a lower cancer incidence. Evidence indicates that some antioxidants inhibit the growth of malignant cells by inducing apoptosis and inhibiting the activity of MMPs. This review is discussed in six subchapters, as follows.

MATRIX METALLOPROTEINASE AND THEIR INHIBITORS: MOLECULAR ASPECTS OF THEIR ROLES IN THE TUMOR METASTASIS

The matrix metalloproteinases (MMPs) are a family of proteolytic enzymes, whose physiological functions include tissue remo-delling and embryogenesis. The importance of this group of proteins in the processes of tumor invasion and metastasis is now widely acknowledged, and has led to the search for MMP inhibitors for use as anticancer treatments in a clinical setting. The review aims to introduce current research relating to MMPs as well as their native and synthetic inhibitor, with particular emphasis on the molecular aspects of their roles in tumor metastasis.

Inhibition of Metalloproteinase Activity by Chinese Formulations Used to Treat Inflammatory Diseases

Matrix metalloproteinases （MMPs） are known to be involved in a number of pathological processes including cancer, atherosclerosis, arthritis and neurodegenerative disease among others. The drive to develop MMP inhibitors as therapeutics has been put forward for years by pharmaceutical companies as well as academicians. In an attempt to screen for MMP inhibitors from Traditional Chinese Medicines （TCMs） , a number of Chinese formulations used to treat inflammatory diseases such as nephritis and hepatitis have been studied. Strong inhibitory effects of three Chinese formulations toward the activity of MMP-16 have been discovered. These results suggest that these anti-inflammatory medicines contain some unknown MMP inhibitory compound（s） and provide reasonable molecular mechanisms for their theraoeutic effects.

Time dependent integration of matrix metalloproteinases and their targeted substrates directs axonal sprouting and synaptogenesis following central nervous system injury

Over the past two decades, many investigators have reported how extracellular matrix molecules act to regulate neuroplasticity. The majority of these studies involve proteins which are targets of matrix metalloproteinases. Importantly, these enzyme/substrate interactions can regulate degenerative and regenerative phases of synaptic plasticity, directing axonal and dendritic reorganization after brain insult. The present review first summarizes literature support for the prominent role of matrix metalloproteinases during neuroregeneration, followed by a discussion of data contrasting adaptive and maladaptive neuroplasticity that reveals time-dependent metalloproteinase/substrate regulation of postinjury synaptic recovery. The potential for these enzymes to serve as therapeutic targets for enhanced neuroplasticity after brain injury is illustrated with experiments demonstrating that metalloproteinase inhibitors can alter adaptive and maladaptive outcome. Finally, the complexity of metalloproteinase role in reactive synaptogenesis is revealed in new studies showing how these enzymes interact with immune molecules to mediate cellular response in the local regenerative environment, and are regulated by novel binding partners in the brain extracellular matrix. Together, these different examples show the complexity with which metalloproteinases are integrated into the process of neuroregeneration, and point to a promising new angle for future studies exploring how to facilitate brain plasticity.

Metalloproteinases as mediators of inflammation and the eyes： molecular genetic underpinnings governing ocular pathophysiology

There are many vision threatening diseases of the eye affecting millions of people worldwide. In this article, we are summarizing potential role of various matrix metalloproteinases （MMPs）; the Zn （2＋）-dependent endoproteases in eye health along with pathogenesis of prominent ocular diseases such as macular degeneration, diabetic retinopathy, and glaucoma via understanding MMPs regulation in affected patients, interactions of MMPs with their substrate molecules, and key regulatory functions of tissue inhibitor of metalloproteinases （TIMPs） towards maintaining overall homeostasis.

Modulation of Matrix Metalloproteinase and TIMP-1 Expression by TGF-β_1 in Cultured Human RPE Cells

In order to investigate the effects of TGF-β1 on the expression of MMP-2, -9 and TIMP- 1 in human retinal pigment epithelial （RPE） cells, the third-sixth passage cultured RPE cells were treated with TGF-β1 at different concentrations （0.01, 0. 1, 1.0, 10 ng/mL）, the expression of MMP-2, -9 and TIMP-1 mRNA was detected by semi-qudntitative RT-PCR assays. MMP-2, -9 and TIMP-1 mRNA were expressed in the cultured RPE cells. The values of MMP-2/β-actin in the cells treated with 0.1, 1.0, 10 ng/mL TGF-β1 were 1.04±0.04, 1.07±0.02 and 1.11±0.03, respectively, significantly higher than in the control group （0.96±0.03, P〈0. 05-0.01）. The expression of MMP-2 mRNA could be up-regulated by TGF-β, , in a dose-dependent manner. The expression of MMP-9 mRNA in the cultured RPE cells was slightly up-regulated by various TGF-β1 concentrations treatment. The values of TIMP-1/β-actin in the cells treated with 0.01 and 0.1 ng/ mL TGF-β1 were 0.85 ±0.01 and 0.97 ± 0.02 respectively, significantly lower than in the control group （1.07±0.04, P〈0.01）, indicating that the expression of TIMP-1 mRNA was down-regulated by TGF-β1 at low concentrations. But along with the increase of TGF-β1 concentrations （1.0 and 10 ng/mL）, the expression of TIMP-1 mRNA was slightly up-regulated, not significantly different from that in the control group （P〉0.05）. It was concluded that TGF-β1 might play an important role in the up-regulation of the expression of MMP-2 in RPE cells and result in a directional shift in the balance between MMP and TIMP. This may be facilitated for RPE cells to migrate in the pathogenesis of vitreoretinopathy.

Immunohistochemical Studies of the Expression of Matrix Metalloproteinase-2 and Metalloproteinase-9 in Human Prostate Cancer

To study the expression of matrix metalloproteinase 2 and 9 in human prostate cancer, matrix metalloproteinase 2 and 9 were immunohistochemically detected in tissues of prostate cancer and benign prostatic hyperplasia (BPH). Our results showed that matrix metalloproteinase 2 and 9 levels in prostate cancer were much higher than those in tissues of BPH, with the cancer invasion being positively correlated with the expression of the metalloproteinases. It is concluded that matrix metalloproteinase 2 and 9 are better molecular markers, which are of help in the diagnosis and prediction of prognosis of prostate cancer.

Diabetes-related intestinal region-specific thickening of ganglionic basement membrane and regionally decreased matrix metalloproteinase 9 expression in myenteric ganglia

BACKGROUND The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy. Regionally distinct thickening of endothelial basement membrane(BM) of intestinal capillaries supplying the myenteric ganglia coincide with neuronal damage in different intestinal segments. Accelerated synthesis of matrix molecules and reduced degradation of matrix components may also contribute to the imbalance of extracellular matrix dynamics resulting in BM thickening. Among the matrix degrading proteinases, matrix metalloproteinase 9(MMP9) and its tissue inhibitor(TIMP1) are essential in regulating extracellular matrix remodelling.AIM To evaluate the intestinal segment-specific effects of diabetes and insulin replacement on ganglionic BM thickness, MMP9 and TIMP1 expression.METHODS Ten weeks after the onset of hyperglycaemia gut segments were taken from the duodenum and ileum of streptozotocin-induced diabetic, insulin-treated diabetic and sex-and age-matched control rats. The thickness of BM surrounding myenteric ganglia was measured by electron microscopic morphometry. Wholemount preparations of myenteric plexus were prepared from the different gut regions for MMP9/TIMP1 double-labelling fluorescent immunohistochemistry. Post-embedding immunogold electron microscopy was applied on ultrathin sections to evaluate the MMP9 and TIMP1 expression in myenteric ganglia and their microenvironment from different gut segments and conditions. The MMP9 and TIMP1 messenger ribonucleic acid(m RNA) level was measured by quantitative polymerase chain reaction.RESULTS Ten weeks after the onset of hyperglycaemia, the ganglionic BM was significantly thickened in the diabetic ileum, while it remained intact in the duodenum. The immediate insulin treatment prevented the diabetes-related thickening of the BM surrounding the ileal myenteric ganglia. Quantification of particle density showed an increasing tendency for MMP9 and a decreasing tendency for TIMP1 from the proximal to the distal small intestine under control conditions. In the diabetic ileum, the number of MMP9-indicating gold particles decreased in myenteric ganglia, endothelial cells of capillaries and intestinal smooth muscle cells, however, it remained unchanged in all duodenal compartments. The MMP9/TIMP1 ratio was also decreased in ileal ganglia only. However, a marked segment-specific induction was revealed in MMP9 and TIMP1 at the m RNA levels.CONCLUSION These findings support that the regional decrease in MMP9 expression in myenteric ganglia and their microenvironment may contribute to extracellular matrix accumulation, resulting in a region-specific thickening of ganglionic BM.

Matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-1 expression in fibrotic rat liver

INTRODUCTIONLiver fibrosis is an excessive deposition ofextracellular matrix(ECM)resulted from bothincreased synthesis and decreased degradation.Matrix metalloproteinases(MMPs)represent agroup of neutral proteinases with variable

Expression of matrix metalloproteinases 2 and 9 in human gastric cancer and superficial gastritis

AIM:To assess expression of matrix metalloproteinases 2(MMP2)and MMP9 in gastric cancer,superficial gastritis and normal mucosa,and to measure metalloproteinase activity.METHODS:MMP2 and MMP9 mRNA expression was determined by quantitative real-time polymerase chain reaction.Normalization was carried out using three different factors.Proteins were analyzed by quantitative gelatin zymography(qGZ).RESULTS:18S ribosomal RNA(18SRNA)was very highly expressed,while hypoxanthine ribosyltransferase-1(HPRT-1)was moderately expressed.MMP2 was highly expressed,while MMP9 was not detected or lowly expressed in normal tissues,moderately or highly expressed in gastritis and highly expressed in cancer.Relative expression of 18SRNA and HPRT-1 showed no significant differences.Significant differences in MMP2 and MMP9 were found between cancer and normal tissue,but not between gastritis and normal tissue.Absolute quantification of MMP9 echoed this pattern,but differential expression of MMP2 proved conflictive.Analysis by qGZ indicated significant differences between cancer and normal tissue in MMP-2,total MMP-9,250 and 110 kDa bands.CONCLUSION:MMP9 expression is enhanced in gastric cancer compared to normal mucosa;interpretation of differential expression of MMP2 is difficult to establish.

Resveratrol inhibits matrix metalloproteinases to attenuate neuronal damage in cerebral ischemia:a molecular docking study exploring possible neuroprotection

The main pathophysiology of cerebral ischemia is the structural alteration in the neurovascular unit, coinciding with neurovascular matrix degradation. Resveratrol has been reported to be one of the most potent chemopreventive agents that can inhibit cellular processes associated with ischemic stroke. Matrix metalloproteinases （MMPs） has been considered as a potential drug target for the treatment of cerebral ischemia. To explore this, we tried to investigate the inter-action of resveratrol with MMPs through molecular docking studies. At 30 minutes before and 2 hours after cerebral ischemia/reperfusion induced by occlusion of the middle cerebral artery, 40 mg/kg resveratrol was intraperitoneally administered. After resveratrol administration, neu-rological function and brain edema were significantly alleviated, cerebral infarct volume was signiifcantly reduced, and nitrite and malondialdehyde levels in the cortical and striatal regions were signiifcantly decreased. The molecular docking study of resveratrol and MMPs revealed that resveratrol occupied the active site of MMP-2 and MMP-9. The binding energy of the complexes was –37.848672 kJ/mol and –36.6345 kJ/mol for MMP-2 and MMP-9, respectively. In case of MMP-2, Leu 164, Ala 165 and Thr 227 were engaged in H-Bonding with resveratrol and in case of MMP-9, H-bonding was found with Glu 402, Ala 417 and Arg 424 residues. These ifndings collectively reveal that resveratrol exhibits neuroprotective effects on cerebral ischemia through inhibiting MMP-2 and MMP-9 activity.

A complete compilation of matrix metalloproteinase expression in human malignant gliomas

Glioblastomas are characterized by an aggressive local growth pattern, a marked degree of invasiveness and poor prognosis. Tumor invasiveness is facilitated by the increased activity of proteolytic enzymes which are involved in destruction of the extracellular matrix of the surrounding healthy brain tissue. Elevated levels of matrix metalloproteinases(MMPs) were found in glioblastoma(GBM) cell-lines, as well as in GBM biopsies as compared with low-grade astrocytoma(LGA) and normal brain samples, indicating a role in malignant progression. A careful review of the available literature revealed that both the expression and role of several of the 23 human MMP proteins is controversely discussed and for some there are no data available at all. We therefore screened a panel of 15 LGA and 15 GBM biopsy samples for those MMPs for which there is either no, very limited or even contradictory dataavailable. Hence, this is the first complete compilation of the expression pattern of all 23 human MMPs in astrocytic tumors. This study will support a better understanding of the specific expression patterns and interaction of proteolytic enzymes in malignant human glioma and may provide additional starting points for targeted patient therapy.

Integrin αvβ6 and matrix metalloproteinase 9 correlate with survival in gastric cancer

AIM: To investigate the expression of integrin αvβ6 and matrix metalloproteinase 9(MMP-9), their association with prognostic factors and to assess their predictive role in gastric cancer patients.METHODS: Immunohistochemistry was used to determine the expressions of integrin αvβ6 and MMP-9 in 126 specimens from patients with primary gastric carcinoma. Associations between immunohistochemical staining and various clinic pathologic variables of tissue specimens were evaluated by the χ2 test and Fisher's exact test. Expression correlation of αvβ6 and MMP-9 was assessed using bivariate correlation analysis. The patients were followed-up every 3 mo in the first two years and at least every 6 mo afterwards, with a median follow-up of 56 mo(ranging from 2 mo to 94 mo).Four different combinations of αvβ6 and MMP-9 levels(that is, both markers positive, both markers negative, αvβ6 positive with MMP-9 negative, and αvβ6 negative with MMP-9 positive) were evaluated for their relative effect on survival. The difference in survival curves was evaluated with a log-rank test. Survival analysis was conducted using the Kaplan-Meier survival and Cox proportional hazards model analysis.RESULTS: The expressions of integrin αvβ6 and MMP-9 were investigated in 126 cases, among which 34.92% were positive for αvβ6 expression, and 42.06% for MMP-9 expression. The expression of αvβ6 was associated with Lauren type, differentiation, N stage, and TNM stage(the P values were 0.006, 0.038, 0.016, and 0.002, respectively). While MMP-9 expression was associated with differentiation, T stage, N stage, and TNM stage(the P values were 0.039, 0.014, 0.033, and 0.008, respectively). The positive correlation between αvβ6 and MMP-9 in gastric cancer was confirmed by a correlation analysis. The Kaplan-Meier survival analysis showed that patients with expression of αvβ6 or MMP-9 alone died earlier than those with negative expression and that patients who were both αvβ6 and MMP-9 positive had a shorter overall survival than those with the opposite pattern(both αvβ6 and MMP-9 negative)(P = 0.000). A Cox model indicated that positive expression of αvβ6 and MMP-9, diffuse Lauren type, as well as a senior grade of N stage, M stage, and TNM stage were predictors of a poor prognosis in univariate analysis. Only αvβ6 and MMP-9 retained their significance when adjustments were made for other known prognostic factors in multivariate analysis(RR = 2.632, P = 0.003 and RR = 1.813, P = 0.007).CONCLUSION: The expression of αvβ6 and MMP-9 are closely correlated, and the combinational pattern of αvβ6 and MMP-9 can serve as a more effective prognostic index for gastric cancer patients.

The Role of Host-derived Dentinal Matrix Metalloproteinases in Reducing Dentin Bonding of Resin Adhesives

Dentin matrix metalloproteinases （MMPs） are a family of host-derived proteolytic enzymes trapped within mineralized dentin matrix, which have the ability to hydrolyze the organic matrix of demineralized dentin. After bonding with resins to dentin there are usually some exposed collagen fibrils at the bottom of the hybrid layer owing to imperfect resin impregnation of the demineralized dentin matrix. Exposed collagen fibrils might be affected by MMPs inducing hydrolytic degradation, which might result in reduced bond strength.Most MMPs are synthesized and released from odontoblasts in the form of proenzymes, requiring activation to degrade extracellular matrix components. Unfortunately, they can be activated by modem self-etch and etch-and-rinse adhe- sives. The aim of this review is to summarize the current knowledge of the role of dentinal host-derived MMPs in dentin matrix degradation. We also discuss various available MMP inhibitors, especially chlorhexidine, and suggest that they could provide a potential pathway for inhibiting collagen degradation in bonding interfaces thereby increasing dentin bonding durability.