Multiple lines of evidence suggest that genetic factors contribute to stroke recovery. The matrix metalloproteinases -2 (MMP-2) and -9 (MMP-9) are modulators of extracellular matrix components, with important regulatory functions in the Central Nervous System (CNS). Shortly after stroke, MMP-2 and MMP-9 have mainly damaging effects for brain tissue. However, MMPs also have a beneficial activity in angiogenesis and neurovascular remodelling during the delayed neuroinflammatory response phase, thus possibly contributing to stroke functional recovery.
In the present study, the role of MMP-2 and MMP-9 genetic variants in stroke recovery was investigated in 546 stroke patients. Functional outcome was assessed three months after a stroke episode using the modified Rankin Scale (mRS), and patients were classified in two groups: good recovery (mRS ≤ 1) or poor recovery (mRS>1). Haplotype tagging single nucleotide polymorphisms (SNPs) in the MMP-2 (N = 21) and MMP-9 (N = 4) genes were genotyped and tested for association with stroke outcome, adjusting for significant non-genetic clinical variables.
Six SNPs in the MMP-2 gene were significantly associated with stroke outcome (0.0018
The results presented strongly indicate that MMP-2 genetic variants are an important mediator of functional outcome after stroke.
The matrix metalloproteinases (MMPs) are a family of proteolytic enzymes. MMPs are known to be involved in tumor invasion, and several have been implicated in tumor prognosis. The aim of this study was to evaluate the prognostic significances of the expressions of MMP-7 and -9 in rectal cancer.
Materials and Methods
The tumor tissues of 87 patients with stage II or III rectal carcinoma that underwent potentially curative resection followed by postoperative adjuvant chemoradiation and 5-fluorouracil based chemotherapy, were investigated immunohistochemically using monoclonal antibodies against MMP-7 and MMP-9. Clinical information, including tumor grades, carcinoembryonic antigen (CEA) levels, and disease-free survival and overall survival were evaluated with respect to the expressions of MMP-7 and -9.
Median follow-up duration was 53.2 months, and median patient age was 55±11 years (range 32~75). MMP-7 expression in tumor tissue was found to be significantly correlated with the presence of nodal metastasis (p=0.029), whilst MMP-9 expression correlated with depth of tumor invasion (p=0.019). No relationships were found between the expressions of MMP-7 or -9 and age, sex, tumor size, tumor grade, or CEA level. Univariate analysis showed that MMP-7 expression was associated with poor 5-year overall survival (12.8 months vs. 65.3 months, p=0.0405). Multivariate analysis confirmed that MMP-7 was independently associated with an adverse outcome (Relative risk: 1.415, p=0.027). However, MMP-9 expression was not found to be related to clinical outcome.
MMP-7 expression in tumor tissue is associated with lymph node metastasis and a poor 5-year overall survival in rectal cancer patients.
Matrix metalloproteinases; Rectal carcinoma; Immunohistochemistry; Prognosis
Matrix metalloproteinases (MMPs) play a pivotal role in tissue remodeling and destruction in inflammation-associated diseases such as cardiovascular disease and periodontal disease. Although it is known that interleukin (IL)-6 is a key proinflamatory cytokine, it remains unclear how IL-6 regulates MMP expression by mononuclear phagocytes. Furthermore, it remains undetermined how IL-6 in combination with hyperglycemia affects MMP expression. In the present study, we investigated the regulatory effect of IL-6 alone or in combination with high glucose on MMP-1 expression by U937 mononuclear phagocytes. We found that IL-6 is a powerful stimulator for MMP-1 expression and high glucose further augmented IL-6-stimulated MMP-1 expression. We also found that high glucose, IL-6, and lipopolysaccharide act in concert to stimulate MMP-1 expression. In the studies to elucidate underlying mechanisms, the extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) pathways were found to be required for stimulation of MMP-1 by IL-6 and high glucose. We also observed that IL-6 and high glucose stimulated the expression of c-Jun, a key subunit of AP-1 known to be essential for MMP-1 transcription. The role of c-Jun in MMP-1 expression was confirmed by the finding that suppression of c-Jun expression by RNA interference significantly inhibited MMP-1 expression. Finally, we demonstrated that similarly to U937 mononuclear phagocytes, IL-6 and high glucose also stimulated MMP-1 secretion from human primary monocytes. In conclusion, this study demonstrated that IL-6 and high glucose synergistically stimulated MMP-1 expression in mononuclear phagocytes via ERK and JNK cascades and c-Jun upregulation.
Matrix metalloproteinases; Interleukin 6; Diabetes; Mitogen-activated protein kinases
The matrix metalloproteinases (MMPs), a family of 25 secreted and cell surface-bound neutral proteinases, process a large array of extracellular and cell surface proteins under normal and pathological conditions. MMPs play critical roles in lung organogenesis, but their expression, for the most part, is downregulated after generation of the alveoli. Our knowledge about the resurgence of the MMPs that occurs in most inflammatory diseases of the lung is rapidly expanding. Although not all members of the MMP family are found within the lung tissue, many are upregulated during the acute and chronic phases of these diseases. Furthermore, potential MMP targets in the lung include all structural proteins in the extracellular matrix (ECM), cell adhesion molecules, growth factors, cytokines, and chemokines. However, what is less known is the role of MMP proteolysis in modulating the function of these substrates in vivo. Because of their multiplicity and substantial substrate overlap, MMPs are thought to have redundant functions. However, as we explore in this review, such redundancy most likely evolved as a necessary compensatory mechanism given the critical regulatory importance of MMPs. While inhibition of MMPs has been proposed as a therapeutic option in a variety of inflammatory lung conditions, a complete understanding of the biology of these complex enzymes is needed before we can reasonably consider them as therapeutic targets.
CD44 is implicated in cell-cell and cell-matrix adhesion, cell migration, and signaling. CD44 cleavage correlates with the tumor burden and metastatic potential in various cancers. In this study, we demonstrate that matrix metalloproteinase-9 (MMP-9) acts as a processing enzyme for CD44 cleavage. Further, this processing event stimulates cell motility and inhibition of either CD44 or MMP-9 inhibited cell migration. MMP-9 and CD44 co-localization on the cell surface was observed in the histological sections of human glioblastoma (GBM) tissues. Confocal microscopy and co-immunoprecipitation studies in GBM xenograft cells further confirm this interaction. The interaction of MMP-9 with CD44 induced CD44 cleavage which was inhibited by both transcriptional knockdown of MMP-9 and with MMP-9 specific inhibitor. Further, supplementation of purified and activated human MMP-9 (hMMP-9) in MMP-9-knockdown cells resumed CD44 cleavage and migration. Additionally, activated hMMP-9 protein induced cleavage of recombinant human CD44 (rhCD44) in an in vitro assay. Selective overexpression of either extracellular domain (CD44ECD) or intracellular domain (CD44ICD) confirmed that CD44ECD played a role in cell migration and invasion. Taken together, our results suggest that MMP-9 is involved in the shedding of CD44 from cancer cells, which would promote the malignant potential of tumor cells.
CD44; MMP-9; invasion; glioblastoma; xenograft cells
Matrix metalloproteases are key regulatory molecules in the breakdown of extracellular matrix and in inflammatory processes. Matrix metalloproteinase-1 (MMP-1) can significantly enhance muscle regeneration by promoting the formation of myofibers and degenerating the fibrous tissue. Herein, we prepared novel MMP-1-loaded poly(lactide-co-glycolide-co-caprolactone) (PLGA-PCL) nanoparticles (NPs) capable of sustained release of MMP-1. We established quadratic equations as mathematical models and employed rotatable central composite design and response surface methodology to optimize the preparation procedure of the NPs. Then, characterization of the optimized NPs with respect to particle size distribution, particle morphology, drug encapsulation efficiency, MMP-1 activity assay and in vitro release of MMP-1 from NPs was carried out. The results of mathematical modeling show that the optimal conditions for the preparation of MMP-1-loaded NPs were as follows: 7 min for the duration time of homogenization, 4.5 krpm for the agitation speed of homogenization and 0.4 for the volume ratio of organic solvent phase to external aqueous phase. The entrapment efficiency and the average particle size of the NPs were 38.75 ± 4.74% and 322.7 ± 18.1 nm, respectively. Further scanning electron microscopy image shows that the NPs have a smooth and spherical surface, with mean particle size around 300 nm. The MMP-1 activity assay and in vitro drug release profile of NPs indicated that the bioactivity of the enzyme can be reserved where the encapsulation allows prolonged release of MMP-1 over 60 days. Taken together, we reported here novel PLGA-PCL NPs for sustained release of MMP-1, which may provide an ideal MMP-1 delivery approach for tissue reconstruction therapy.
Matrix metalloproteinase-1; PLGA-PCL; Nanoparticles; Rotatable central composite design; Response surface methodology
92 kDa matrix metalloproteinase-9 (MMP-9) is believed to play an important role in degrading the matrix and basement membrane, contributing to the invasion and metastasis of malignant solid tumors. However, little is known about its involvement in a malignant fibrous histiocytoma. The aim of this study was to investigate the expression of MMP-9 and to correlate its expression with clinicopathologic parameters in human malignant fibrous histiocytomas.
Materials and Methods
Archival tumor tissues from 20 patients with a malignant fibrous histiocytoma were analyzed by immunohistochemistry for the expression of MMP-9. Clinical information was obtained through the computerized retrospective database from the tumor registry.
Seventeen of 20 (85%) tumors showed a positive reaction for MMP-9. MMP-9 activity was inversely correlated with patients' survival time (p=.011). There was no significant correlation between the activated MMP-9 expression and all the other clinicopathologic variables.
Our data demonstrate that MMP-9 activation is likely to occur in human malignant fibrous histiocytomas. It is also noteworthy that the expression of MMP-9 may aid in predicting patients' poor prognosis.
MMP-9; Malignant histiocytic disorder
As their name implies, MMPs were first described as proteases that degrade extracellular matrix proteins, such as collagens, elastin, proteoglycans, and laminins. However, studies of MMP function in vivo have revealed that these proteinases act on a variety of extracellular protein substrates, often to activate latent forms of effector proteins, such as antimicrobial peptides and cytokines, or to alter protein function, such as shedding of cell-surface proteins. Because their substrates are diverse, MMPs are involved in variety of homeostatic functions, such as bone remodeling, wound healing, and several aspects of immunity. However, MMPs are also involved in a number of pathological processes, such as tumor progression, fibrosis, chronic inflammation, tissue destruction, and more. A key step in regulating MMP proteolysis is the conversion of the zymogen into an active proteinase. Several proMMPs are activated in the secretion pathway by furin proprotein convertases, but for most the activation mechanisms are largely not known. In this review, we discuss both authentic and potential mechanisms of proMMP activation.
Matrix metalloproteinase; zymogen; proteolysis; adaptor molecules
Prosthetic mesh implants are widely used in hernia surgery. To show long-term mesh-related complications such as shrinkage or adhesions, a precise visualization of meshes and their vicinity in vivo is important. By supplementing mesh fibers with ferro particles, magnetic resonance imaging (MRI) can help to delineate the mesh itself. This study aimed to demonstrate and quantify time-dependent mesh shrinkage in vivo by MRI.
Polyvinylidenfluoride (PVDF) meshes with incorporated superparamagnetic iron oxides (SPIOs) were implanted as an abdominal wall replacement in 30 rats. On days 1, 7, 14, or 21, MRI was performed using a gradient echo sequence with repetition time (TR)/echo time (TE) of 50/4.6 and a flip angle of 20°. The length, width, and area of the device were measured on axial, coronal, and sagittal images, and geometric deformations were assessed by surgical explantation.
In all cases, the meshes were visualized and their area estimated by measuring the length and width of the mesh. The MRI presented a mean area shrinkage in vivo of 13% on day 7, 23% on day 14, and 23% on day 21. Postmortem measurements differed statistically from MRI, with a mean area shrinkage of 23% on day 7, 28% on day 14, and 30% on day 21. Ex vivo measurements of shrinkage showed in vivo measurements to be overestimated approximately 8%. Delineation of the mesh helped to show folding or adhesions close to the intestine.
Loading of surgical meshes with SPIOs allows their precise visualization during MRI and guarantees an accurate in vivo assessment of their shrinkage. The authors’ observation clearly indicates that shrinkage in vivo is remarkably less than that shown by illustrated explantation measurements. The use of MRI with such meshes could be a reliable technique for checking on proper operation of implanted meshes and showing related complications, obviating the need for exploratory open surgical revision.
Magnetic resonance imaging; SPIO; Mesh implant; Shrinkage
Abnormal angiogenesis and vascular remodeling contribute to pathogenesis of a number of disorders such as tumor, arthritis, atherosclerosis, restenosis, hypertension, and neurodegeneration. During angiogenesis and vascular remodeling, behaviors of stem/progenitor cells, endothelial cells (ECs), and vascular smooth muscle cells (VSMCs) and its interaction with extracellular matrix (ECM) play a critical role in the processes. Matrix metalloproteinases (MMPs), well-known inflammatory mediators are a family of zinc-dependent proteolytic enzymes that degrade various components of ECM and non-ECM molecules mediating tissue remodeling in both physiological and pathological processes. MMPs including MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-12, and MT1-MMP, are stimulated and activated by various stimuli in vascular tissues. Once activated, MMPs degrade ECM proteins or other related signal molecules to promote recruitment of stem/progenitor cells and facilitate migration and invasion of ECs and VSMCs. Moreover, vascular cell proliferation and apoptosis can also be regulated by MMPs via proteolytically cleaving and modulating bioactive molecules and relevant signaling pathways. Regarding the importance of vascular cells in abnormal angiogenesis and vascular remodeling, regulation of vascular cell behaviors through modulating expression and activation of MMPs shows therapeutic potential.
Mesenchymal stem cells (MSCs) are known to be capable of suppressing immune responses, but the molecular mechanisms involved and the therapeutic potential of MSCs remain to be clarified.
RESEARCH DESIGN AND METHODS
We investigated the molecular mechanisms underlying the immunosuppressive effects of MSCs in vitro and in vivo.
Our results demonstrate that matrix metalloproteinases (MMPs) secreted by MSCs, in particular MMP-2 and MMP-9, play an important role in the suppressive activity of MSCs by reducing surface expression of CD25 on responding T-cells. Blocking the activity of MMP-2 and MMP-9 in vitro completely abolished the suppression of T-cell proliferation by MSCs and restored T-cell expression of CD25 as well as responsiveness to interleukin-2. In vivo, administration of MSCs significantly reduced delayed-type hypersensitivity responses to allogeneic antigen and profoundly prolonged the survival of fully allogeneic islet grafts in transplant recipients. Significantly, these MSC-mediated protective effects were completely reversed by in vivo inhibition of MMP-2 and MMP-9.
We demonstrate that MSCs can prevent islet allograft rejection leading to stable, long-term normoglycemia. In addition, we provide a novel insight into the mechanism underlying the suppressive effects of MSCs on T-cell responses to alloantigen.
Matrix metalloproteases (MMPs) are key regulatory molecules in the formation, remodeling and degradation of extracellular matrix (ECM) components in both physiological and pathological processes in many tissues. In skeletal muscle, MMPs play an important role in the homeostasis and maintenance of myofiber functional integrity by breaking down ECM and regulating skeletal muscle cell migration, differentiation and regeneration. Skeletal muscle satellite cells, a group of quiescent stem cells located between the basement membrane and the plasmalemma of myofibers, are responsible for lifelong maintenance and repairing, which can be activated and as a result migrate underneath the basement membrane to promote regeneration at the injured site. MMPs are able to degrade ECM components, thereby facilitating satellite cell migration and differentiation. This current review will focus on the critical roles of MMPs in skeletal muscle injury and repair, which include satellite cell activation with migration and differentiation. The effect of MMPs on muscle regeneration and fibrous scar tissue formation, as well as therapeutic insights for the future will be explored.
matrix metalloproteinases; skeletal muscle satellite cells; migration; differentiation; regeneration; fibrosis
Hepatic stellate cells (HSC) changed their morphology and function including production of matrix metalloproteinases (MMPs) in response to extracellular matrix (ECM) component used as a substratum in culture. We examined in this study the regulatory role of ECM component on expression of MMPs and tissue inhibitor of metalloproteinase (TIMP) in rat HSCs cultured on polystyrene, type I collagen-coated surface, type I collagen gel, or Matrigel, respectively. When cultured on type I collagen gel, HSCs showed the asteroid cell shape and MMP-1 activity, as detected by in situ zymography. Expression of MMP-1 protein and mRNA were examined by using immunofluorescence staining and RT-PCR analysis in HSCs cultured on type I collagen gel. Active form of MMP-2 was detected by gelatin zymography in the conditioned medium of HSCs cultured on type I collagen gel, whereas it was not detected when HSCs were cultured on polystyrene, type I collagen-coated surface, or Matrigel. Increased MMP-2 mRNA was detected by RT-PCR in HSCs cultured on type I collagen gel. Increased MT1-MMP proteins were shown to localize on the cell membrane by using immunofluorescence staining in HSCs cultured on type I collagen gel. Elevated expression of membrane-type matrix metallproteinase-1 (MT1-MMP) mRNA and tissue inhibitor of metalloproteinase-2 (TIMP-2) mRNA was detected by RT-PCR in HSCs cultured on type I collagen-coated surface or type I collagen gel. These results indicate that expression of MMPs and TIMP-2 is regulated by ECM components in cultured HSCs, suggesting an important role of HSCs in the remodeling of liver tissue.
Matrix metalloproteinases (MMPs) have repeatedly been shown to play a very active role in extracellular matrix degradation associated with tumor invasion and metastasis. Tissue inhibitors of MMPs (TIMPs) are well-known for their ability to inhibit MMP activity thereby inhibiting malignant progression. Inositol hexaphosphate (IP6 phytic acid) has been recognized to have both preventive and therapeutic effects against various cancers including that of colon. In in vitro studies, IP6 has been demonstrated to inhibit cancer cell adhesion and migration. In the present study, the effect of IP6 on the expression of MMP and TIMP genes was evaluated in unstimulated and IL-1β-stimulated colon cancer cell line Caco-2.
Materials and methods
Real-time QRT-PCR was used to validate the transcription level of selected MMP and TIMP genes in Caco-2 cells after treatment with 1 ng/ml of IL-1β, 2.5 mM of IP6, and both for 6, 12, and 24 h.
Stimulation of cells with IL-1β only resulted in an overexpression of MMP and their TIMP mRNAs. A significant decrease in MMP-13, MMP-3, MMP-2, and TIMP-1 basal expression was achieved by IP6. IP6 was also an efficient downregulator of MMP-1, MMP-9, and TIMP-2 genes transcription stimulated by IL-1β in 6 h lasting culture. After 12 h, IL-1β-induced MMP-2 mRNA expression was significantly reduced by IP6.
Proinflammatory cytokine IL-1β upregulates MMP and TIMP mRNAs expression in colon cancer epithelial cells Caco-2. IP6 (2.5 mM) influences constitutive expression of both MMP and TIMP genes and downregulates IL-1β stimulated transcription of some of these genes. IP6 exerts its anti-metastatic activity through modulation of MMP and TIMP genes expression to prevent cancer cell migration and invasion.
IP6; Inflammation; Metastases; Colon cancer; Real-time QRT-PCR
Pulmonary fibrosis is characterized by excessive deposition of extracellular matrix in the interstitium resulting in respiratory failure. The role of remodeling mediators such as metalloproteinases (MMPs) and their inhibitors (TIMPs) in the fibrogenic process remains misunderstood. In particular, macrophage metalloelastase, also identified as MMP-12, is known to be involved in remodeling processes under pathological conditions. However, MMP-12 involvement in pulmonary fibrosis is unknown. Here we investigated fibrotic response to bleomycin in MMP-12 deficient mice.
Materials and methods
C57BL/6 mice, Balb/c mice and MMP-12 -/- mice with a C57BL/6 background received 0.3 mg bleomycin by intranasal administration. 14 days after, mice were anesthetized and underwent either bronchoalveolear lavage (BAL) or lung removal. Collagen deposition in lung tissue was determined by Sircol™ collagen assay, MMP activity in BAL fluid was analyzed by zymography, and other mediators were quantified in BAL fluid by ELISA. Real time PCR was performed to assess gene expression in lung removed one or 14 days after bleomycin administration. Student t test or Mann & Whitney tests were used when appropriate for statistical analysis.
The development of pulmonary fibrosis in "fibrosis prone" (C57BL/6) mice was associated with prominent MMP-12 expression in lung, whereas MMP-12 expression was weak in lung tissue of "fibrosis resistant" (Balb/c) mice. MMP-12 mRNA was not detected in MMP-12 -/- mice, in conformity with their genotype. Bleomycin elicited macrophage accumulation in BAL of MMP-12 -/- and wild type (WT) mice, and MMP-12 deficiency had no significant effect on BAL cells composition. Collagen content of lung was increased similarly in MMP-12 -/- and WT mice 14 days after bleomycin administration. Bleomycin elicit a raise of TGF-β protein, MMP-2 and TIMP-1 protein and mRNA in BAL fluids and lung respectively, and no significant difference was observed between MMP-12 -/- and WT mice considering those parameters.
The present study shows that MMP-12 deficiency has no significant effect on bleomycin-induced fibrosis.
Matrix metalloproteinase 20 (MMP20) and kallikrein-related peptidase 4 (KLK4) are thought to be necessary to clear proteins from the enamel matrix of developing teeth. We characterized Mmp20 and Klk4 null mice to better understand their roles in matrix degradation and removal. Histological examination showed retained organic matrix in Mmp20, Klk4, and Mmp20/Klk4 double-null mouse enamel matrix, but not in the wild-type. X-gal histostaining of Mmp20 null mice heterozygous for the Klk4 knockout/lacZ knockin showed that Klk4 is expressed normally in the Mmp20 null background. This finding was corroborated by zymogram and western blotting, which discovered a 40-kDa protease induced in the maturation stage of Mmp20 null mice. Proteins were extracted from secretory-stage or maturation-stage maxillary first molars from wild-type, Mmp20 null, Klk4 null, and Mmp20/Klk4 double-null mice and were analyzed by SDS-PAGE and western blotting. Only intact amelogenins and ameloblastin were observed in secretory-stage enamel of Mmp20 null mice, whereas the secretory-stage matrix from Klk4 null mice was identical to the matrix from wild-type mice. More residual matrix was observed in the double-null mice compared with either of the single-null mice. These results support the importance of MMP20 during the secretory stage and of KLK4 during the maturation stage and show there is only limited functional redundancy for these enzymes.
enamel; enamel maturation; kallikrein 4; proteases; proteinases; teeth
Matrix Metalloproteinase 9 (MMP-9) expression is known to enhance the invasion and metastasis of tumor cells. In previous work based on a proteomic screen, we identified the serpin Protease nexin-1 (PN-1) as a potential target of MMP-9. Here we demonstrate that PN-1 is a substrate for MMP-9 and establish a link between PN-1 degradation by MMP-9 and regulation of invasion. PN-1 levels increased in prostate carcinoma cells after downregulation of MMP-9 and in tissues of MMP-9 deficient mice, consistent with MMP-9 acting to degrade PN-1. We identified three MMP-9 cleavage sites in PN-1 and demonstrated that mutations in those sites made PN-1 more resistant to MMP-9. Urokinase plasminogen activator (uPA) is inhibited by PN-1. MMP-9 augmented uPA activity in the medium of PC3-ML cells by degrading PN-1. Prostate cancer cells, overexpressing PN-1 or treated with MMP-9 shRNA, had reduced cell invasion in matrigel. PN-1 siRNA restored uPA activity and the invasive capacity. PN-1 mutated in the serpin inhibitory domain, the reactive centre loop (RCL), failed to inhibit uPA and failed to reduce matrigel invasion. Taken together, this study demonstrates a novel molecular pathway in which MMP-9 regulates uPA activity and tumor cell invasion through cleavage of PN-1.
The extracellular matrix (ECM) is a critical determinant of neovessel integrity. Materials and Methods: Thirty-six (polyglycolic acid + polycaprolactone and poly lactic acid) tissue-engineered vascular grafts seeded with syngeneic bone marrow mononuclear cells were implanted as inferior vena cava interposition grafts in C57BL/6 mice. Specimens were characterized using immunohistochemical staining and qPCR for representative ECM components in addition to matrix metalloproteinases (MMPs). Total collagen, elastin, and glycosaminoglycan (GAG) contents were determined. MMP activity was measured using zymography.
Collagen production on histology demonstrated an initial increase in type III at 1 week followed by type I production at 2 weeks and type IV at 4 weeks. Gene expression of both type I and type III peaked at 2 weeks, whereas type IV continued to increase over the 4-week period. Histology demonstrated fibrillin-1 deposition at 1 week followed by elastin production at 4 weeks. Elastin gene expression significantly increased at 4 weeks, whereas fibrillin-1 decreased at 4 weeks. GAG demonstrated abundant production at each time point on histology. Gene expression of decorin significantly increased at 4 weeks, whereas versican decreased over time. Biochemical analysis showed that total collagen production was greatest at 2 weeks, and there was a significant increase in elastin and GAG production at 4 weeks. Histological characterization of MMPs showed abundant production of MMP-2 at each time point, while MMP-9 decreased over the 4-week period. Gene expression of MMP-2 significantly increased at 4 weeks, whereas MMP-9 significantly decreased at 4 weeks.
ECM production during neovessel formation is characterized by early ECM deposition followed by extensive remodeling.
Tissue engineering; Extracellular matrix; Vascular remodeling; Collagen; Elastin
Pelvic organ prolapse (POP) is a common gynecological problem. Repair with synthetic materials such as prolene mesh has become a popular approach in prolapsus surgery. Migration of synthetic materials can cause serious complications.
PRESENTATION OF CASE
A 69-year-old woman was admitted to the hospital with a complaint of sensation of fullness and a feeling of a foreign material protruding during defecation. The patient underwent exploratory laparotomy. Prolene mesh was detected in sacral region but resection of the mesh could not be conducted because of dense adhesions causing frozen pelvis. The migrated prolene mesh was resected transanally.
Genital prolapse or genital hernia is described as the protrusion of pelvic organs along the vagina. It is one of the common gynecological conditions that affect the quality of life in women. Mesh migration is a well-known clinical pathology.
Mesh migration is a serious complication after sacral colpopexy. Surgical resection of migrated mesh can be difficult due to dense adhesions.
Sacral colpopexy; Mesh; Migration
Genetic variants influencing lung function or immune system may be involved in the development of asthma and/or its symptoms. Matrix metalloproteinases (MMPs) contribute to both normal and pathological tissue remodeling and also act as regulatory molecules by processing cytokines or adhesion molecules. In animal models, growing evidences suggest that MMPs play important roles in asthma phenotypes. Some MMP genes (e.g. MMP-9 and MMP-12) have recently been shown to be associated with asthma in Caucasian populations. We investigated whether single nucleotide polymorphisms (SNPs) in MMP-7 and MMP-12 could affect the susceptibility to and clinical phenotypes of asthma in the Japanese population.
We conducted a case-control study between SNPs in MMP-7 and MMP-12 genes and asthma-related phenotypes using childhood and adult Japanese populations (653 childhood asthma patients and 423 controls, and 428 adult asthma patients and 646 controls, respectively). To investigate the effects of amino acid substitutions by SNPs on MMPs' enzymatic activity, MMP activity assays were performed using commercially available kits based on fluorescence resonance energy transfer (FRET) peptide. We also evaluated the effect of 3’UTR SNP in MMP-7 on its mRNA stability and the effect of SNP in MMP-12 on its antimicrobial activity.
We found that, in the Japanese population, SNPs of MMP-7 (rs10502001, G/A, Arg77His; rs14983, C/T, 3’UTR) (P = 0.006; odds ratio (OR), 1.46; 95% confidential interval (CI), 1.126-1.903) and MMP-12 (rs652438, A/G, Asn357Ser) (P = 0.015; OR, 1.60; 95% CI, 1.002-2.556) showed significant association with adult and childhood asthma, respectively. We also found that the SNP (rs652438) in MMP-12 was associated with severity in adult asthma (P = 0.010). Using supernatant from cultured HEK293 cells stably transfected with the pcDNA3.1(+)-MMP-7 or MMP-12 as MMP proteins, we evaluated activation kinetics, rate of proteolytic cleavage of FRET peptide, Michaelis constant, and substrate specificity of the enzyme. In this system, we couldn't detect the functional effects of amino acid substitutions by SNPs on the enzymatic activity.
Our association study suggested that genetic variants of MMP7 and MMP12 conferred risk for development of asthma in the Japanese population.
Matrix metalloproteinases (MMPs) are key regulatory molecules in the formation, remodeling and degradation of all extracellular matrix (ECM) components in both physiological and pathological processes in various tissues. The aim of this study was to examine the involvement of gelatinase MMP family members, MMP-2 and MMP-9, in dystrophin-deficient skeletal muscle. Towards this aim, we made use of the canine X-linked muscular dystrophy in Japan (CXMDJ) model, a suitable animal model for Duchenne muscular dystrophy.
We used surgically biopsied tibialis cranialis muscles of normal male dogs (n = 3) and CXMDJ dogs (n = 3) at 4, 5 and 6 months of age. Muscle sections were analyzed by conventional morphological methods and in situ zymography to identify the localization of MMP-2 and MMP-9. MMP-2 and MMP-9 activity was examined by gelatin zymography and the levels of the respective mRNAs in addition to those of regulatory molecules, including MT1-MMP, TIMP-1, TIMP-2, and RECK, were analyzed by semi-quantitative RT-PCR.
In CXMDJ skeletal muscle, multiple foci of both degenerating and regenerating muscle fibers were associated with gelatinolytic MMP activity derived from MMP-2 and/or MMP-9. In CXMDJ muscle, MMP-9 immunoreactivity localized to degenerated fibers with inflammatory cells. Weak and disconnected immunoreactivity of basal lamina components was seen in MMP-9-immunoreactive necrotic fibers of CXMDJ muscle. Gelatinolytic MMP activity observed in the endomysium of groups of regenerating fibers in CXMDJ did not co-localize with MMP-9 immunoreactivity, suggesting that it was due to the presence of MMP-2. We observed increased activities of pro MMP-2, MMP-2 and pro MMP-9, and levels of the mRNAs encoding MMP-2, MMP-9 and the regulatory molecules, MT1-MMP, TIMP-1, TIMP-2, and RECK in the skeletal muscle of CXMDJ dogs compared to the levels observed in normal controls.
MMP-2 and MMP-9 are likely involved in the pathology of dystrophin-deficient skeletal muscle. MMP-9 may be involved predominantly in the inflammatory process during muscle degeneration. In contrast, MMP-2, which was activated in the endomysium of groups of regenerating fibers, may be associated with ECM remodeling during muscle regeneration and fiber growth.
Plaque rupture is the main cause of acute myocardial infarction and stroke. Atherosclerotic plaques have been described to be vulnerable and more prone to rupture when they are characterized by thin, highly inflamed, and collagen-poor fibrous caps and contain elevated levels of proteases, including metalloproteinases (MMPs). Initiation of collagen breakdown in plaques requires interstitial collagenases, a MMP subfamily consisting of MMP-1, MMP-8, and MMP-13. Previous reports demonstrated that MMP-1 and MMP-13 might be overexpressed in both human and experimental atherosclerosis. Since neutrophils have been only recently reported in atherosclerotic plaques, the role of MMP-8 (formerly known as “neutrophil collagenase”) was only marginally evaluated. In this paper, we will update and comment on evidence of the most relevant regulatory pathways and activities mediated by MMP-8 in atherogenesis.
The study sought evidence for apoptosis, the expression of MMP-1, MMP-3 and TIMP-2 and their effect on the mechanical and biochemical properties of rabbit fresh knee medial meniscal grafts in a 6-month follow-up.
Material and methods
Forty white male New Zealand rabbits were chosen for the study. The medial meniscus was excised from 28 animals and stored under tissue culture conditions for 2 weeks, following which 14 of them were implanted as autografts and 14 as allografts. When the animals were euthanized, 20 menisci were used for immunohistochemical examinations. Apoptosis (TUNEL method) and MMP-1, MMP-3 and TIMP-2 immunoexpression were estimated semiquantitatively. The other 20 menisci were subjected to biochemical analysis and their degree of elasticity was evaluated.
An increased level of apoptosis (p <0.05) was observed both in allografts (1.57 ±0.98) and autografts (0.86 ±0.69); no statistical differences existed between them. An increased level of metalloproteinases and TIMP-2 expression was observed only in the allografts (p < 0.05). The highest decrease of degree of elasticity and the most significant changes in biochemical composition were observed in allografts (p < 0.05).
The studies confirmed the existence of excessive apoptosis in both kinds of fresh viable medial meniscal implants: auto- and allografts. Our results suggest that apoptosis and increased MMP-1 and MMP-3 expression have an adverse effect on the biological properties of implants. The results of experimental studies on humans indicate the need to devise a method of apoptosis inhibition in transplanted menisci to improve long-term results.
apoptosis; metalloproteinases; viable meniscal transplant properties