Matrix Degradation Processes Research Articles

Computational study of local and global ECM degradation and the effects on cell speed and cell–matrix tractions

Cell migration is important to biological processes such as wound healing and cancer invasion. Cell movement involves forming bonds between cell surface receptors and ligands present in the extracellular matrix (ECM) in order to generate the necessary forces on the matrix. For three-dimensional cell migration, partial degradation of the adjacent ECM using matrix metalloproteinases is necessary to create a passage with less motion resistance. Our mathematical model takes into consideration cell–ECM tractions needed to drive cell movement, viscous drag forces, and a transient matrix degradation process. Simulations were performed for global and highly localized matrix degradation processes, where the latter occurred at the cell–ECM interface. It was observed that the higher the speed of the cell boundary, the higher the matrix concentration after localized degradation. The results showed that a greater ECM degradation coefficient was needed for optimal cell migration to occur for the local process and that cell–ECM tractions were larger. The results from this investigation complement those obtained by other studies where it has been shown that cell speed is a biphasic function of ligand and matrix metalloproteinase concentration, and would also be of use for research on wound healing, cancer cell invasion, and tissue engineering.

Aberrant protein expression in the placenta of cloned mouse derived from embryonic stem cell

Placentomegaly is a common phenotype in cloned mice. To assess differences in protein expression between placentae of cloned and uncloned mice, we used a proteomic approach involving 2-dimensional electrophoresis (DE) and MALDI-TOF MS. Proteins within isoelectric point range of 4–11 separately were analyzed in 2-DE with 3 replications of each sample. A total of approximately 3500 spots were detected in placental 2-DE stained with Coomassie blue. In the comparison of normal and cloned samples, a total of 41 spots were identified as differentially expressed proteins, of which 25 spots were up-regulated proteins such as TIMP-2, glutamate-ammonia, and esterase 10, while 16 spots were down-regulated proteins such as PBEF and annexin A1. The TIMP-2, which is related to extracellular matrix degradation and tissue remodeling processes, is an inhibitor of MMP-2. The PBEF is related to inhibition of apoptosis and induction of spontaneous labor. Western blot analysis confirmed increased TIMP-2 expression and decreased PBEF expression in cloned placentae compared with normal controls. Our results demonstrated composite profiles of key proteins involved in abnormal hypertrophic placenta derived from cloned mice and suggested that the reason for the placentomegaly may be due to abnormal gene expression in cloned mice.

Demethoxycurcumin suppresses migration and invasion of MDA-MB-231 human breast cancer cell line

Demethoxycurcumin (DMC) is one of the main active compounds of curcuminoids found in turmeric powder, which is used as a spice in Asian cooking and traditional medicine. Recent studies reveal that DMC has several biological activities including anti-inflammation and anti-cancer activities. However, the molecular mechanism by which DMC has anti-metastasis activity in breast cancer cells remains poorly understood. Here, we report for the first time that DMC inhibited adhesion, migration and invasion of MDA-MB-231 human breast cancer cells. For cancer cell migration and invasion, extracellular matrix (ECM) degradation processes are required. MDA-MB-231 cells treated with DMC had decreased levels of ECM degradation-associated proteins including matrix metalloproteinase-9 (MMP-9), membrane type-1 matrix metalloproteinase (MT1-MMP), urokinase plasminogen activator (uPA) and uPA receptor (uPAR), while the level of uPA inhibitor (PAI-1) was up-regulated. Moreover, DMC also reduced the expression of intercellular adhesion molecule-1 (ICAM-1) and chemokine receptor 4, (CXCR4), which is involved in modulation of the tumor metastasis process. We also found that DMC treatment inhibited the DNA binding activity of nuclear factor-kappa B (NF-κB), which is known to mediate the expression of MMPs, uPA, uPAR, ICAM-1, and CXCR4. These findings strongly suggest that the mechanism of DMC-mediated anti-invasive activity involves modulation of the expression of invasion-associated proteins, possibly by targeting NF-κB in MDA-MB-231 cells.

Biochemical Investigation of Some Proteins from Human Primary Teeth to Evaluate Heavy Metal Pollution

This investigation is based on the premise that heavy metals are sequestered by the mineral phase of teeth [1,2], hydroxyapatite, during their formation and there is a relation between heavy metal pollution and progressive destruction of human primary tooth. Our study was carried out on temporary molars – sound and carious - extracted from children up to 6 year old, residing in an area of Romania known to be highly polluted with heavy metals (Pb and Cd). In carious dentin extracts we found increased levels of collagen type 1 and alkaline phosphatase activity that can be correlated with the remineralization processus during teeth decay. Gelatin zymography shown increased MMP-1 (type-I collagenase) and MMP-2 (gelatinase-A) activities only in dentin extract from carious teeth isolated from children residing in a highly polluted area, suggesting their role in pathological extracellular matrix (ECM) remodeling and degradation processes in the progression of carious decay.

Atherosclerotic Plaque Stability—What Determines the Fate of a Plaque?

Although the understanding of the underlying pathology of atherosclerosis has improved in recent years, the disease is still the main cause of death globally. Current evidence has implicated the role of inflammation in atherogenesis and plaque destabilization. Thus, inflammatory cytokines may attenuate interstitial collagen synthesis, increase matrix degradation, and promote apoptosis in several atheroma-associated cell types, and all these cellular events may enhance plaque vulnerability. Several cell types found within the lesion (ie, monocyte/macrophages, T cells, mast cells, platelets) contribute to this immune-mediated plaque destabilization, and a better understanding of these processes is a prerequisite for the development of new treatment strategies in these individuals. Such knowledge could also facilitate a better identification of high-risk individuals. In the present study, these issues will be discussed in more detail, particularly focusing on the interactions between matrix degradation, apoptotic, and inflammatory processes in plaque destabilization.

Collagen Type-I α1 Chain mRNA is Expressed in the Follicle Cells of the Medaka Ovary

Follicle rupture during ovulation is a well-regulated biological process of extracellular matrix degradation in the vertebrate ovary. Although proteolytic enzymes responsible for the rupture have recently been identified in the medaka, Oryzias latipes , the lack of knowledge about the ovarian expression and distribution of extracellular matrix components in lower vertebrates prevents the understanding of this process's molecular mechanism. To approach the problem, we cloned a cDNA coding for the medaka collagen type-I alpha1 chain and examined its mRNA expression in the fish ovary. The deduced amino acid sequence of the collagen type-I alpha1 chain was homologous to those of the proteins from other vertebrate species. The alpha1 chain mRNA was expressed in various tissues of the adult fish. In the ovary sections of mature female fish, this mRNA was detected in a line surrounding ovarian follicles of all sizes. A comparison with the distribution of gelatinase B mRNA in follicles that had just ovulated indicated that the collagen type-I alpha1 gene is expressed in the theca cells. The current results strongly suggest that collagen type I is synthesized by theca cells and is localized in the same cell layer of the follicles.

Role of the plasminogen activation system in extracellular matrix degradation processes in normal or pathological conditions in sheep

The plasminogen activation system has traditionally been implicated in various fibrinolytic mechanisms. However, its role in non-fibrinolytic processes is not well established. This article summarizes our current knowledge on the role of plasminogen activation system in extracellular proteolysis, mainly in the male and female reproductive systems, in encephalopathies and in various infectious diseases of sheep.

Mast cell tryptase and photoaging: possible involvement in the degradation of extra cellular matrix and basement membrane proteins

Mast cells are widely distributed in the connective tissue of the body, but are particularly prominent in tissues such as skin. An increased number of mast cells can be found in the dermis under inflammatory conditions and ultraviolet (UV) exposed skin. Previous investigations have identified matrix metalloproteinases (MMPs) as key enzymes in the degradation of extra cellular matrix (ECM). This study reports about the potential contribution of human mast cell tryptase as a new triggering enzyme in matrix degradation process. Recent studies suggest that mast cell-derived proteases can activate MMPs. We investigated both the degradation of cellular matrix components and activation of MMPs by human tryptase. Mast cells are increased in photoaged skin and the increase of mast cell tryptase in UV irradiated skin was confirmed. Human mast cell tryptase was purified from human tonsils by a series of standard chromatographic procedures. Degradation of collagen type I was achieved by incubation of human type I collagen with tryptase and the fragments were quantified by SDS-PAGE and staining with Coomassie Brilliant Blue 250-R (CBB). Treatment with tryptase resulted in the activation of proMMP-9 as revealed by gelatinolytic activity in type IV collagen zymography. When tryptase was incubated with human type IV collagen, gradual degradation of intact collagen was detected by Western blotting. Furthermore, type IV collagen degradation was observed in the basement membrane (BM) of a three-dimensional (3D) skin model. Degranulation of mast cells, which release tryptase, can activate MMPs and causes direct damage to ECM proteins. These findings strongly implicate that tryptase either alone or in conjunction with activation of MMPs, can participate in ECM damage and the possible destruction of BM leading to photoaging.

Prognostic impact of MKI67 and MMP1 in node-negative invasive ductal and invasive lobular carcinoma of the breast

21102 Background: MKI67 and MMP1 mRNA, which might reflect the biological processes of tumor proliferation and matrix degradation, respectively, have been proposed as prognostic marker in invasive carcinoma of the breast. We compared the expression of both genes in invasive lobular versus invasive ductal carcinoma, which represent the most common histological breast cancer subtypes. Methods: MKI67 and MMP1 mRNA expression was determined by microarray analysis of fresh frozen tumor tissue of 118 patients with invasive ductal and 39 patients with invasive lobular carcinoma. We compared the distribution of these markers between both histological subtypes as well as within each subtype between tumors from patients with or without subsequent distant metastasis or local recurrence by two tailed Mann-Whitney test. Results: MKI67 as marker of proliferation and MMP1 as marker of matrix degradation were significantly elevated in invasive ducal versus lobular carcinomas (p = 0.023 and p < 0.0001, respectively). Furthermore, elevation of both markers were significantly associated with the occurrence of metastasis in ductal (p = 0.023 and p = 0.012) but not in lobular carcinomas (p = 0.986 and p = 0.366). In addition, no significant association was found between these markers and development of local recurrence in patients with ductal (p = 0.304 and p = 0.899) or lobular (p = 0.891 and p= 0.153) carcinomas . Conclusions: Our data suggest that differences exist between ductal and lobular carcinoma of the breast regarding both the expression and the prognostic impact of MKI67 and MMP1. Furthermore, the prognostic relevance of proliferation and matrix degradation was more important for the development of distant metastasis than for the development of local recurrence in ductal carcinoma emphasizing differences in the underlying biology of local recurrence and distant metastasis. No significant financial relationships to disclose.

TGF‐β1 overexpression in the transversalis fascia of patients with direct inguinal hernia

The aetiology of inguinal hernia includes changes in collagen turnover and metalloproteinase (MMP) expression, and direct hernia has been linked to increased MMP-2 expression. Since transforming growth factor beta1 (TGFbeta1) plays a role in tissue remodelling, this growth factor could directly affect metalloproteinase secretion and thus the proteolytic activity of these enzymes. We hypothesized that TGFbeta1 expression could also be altered in direct inguinal hernias. Tissue specimens were obtained from the transversalis fascia (TF) of organ donors (controls; n = 10) and patients with inguinal hernia (indirect; n = 20/direct; n = 20), who were also divided into two groups according to age (20-40/41-60 years). Tissue sections were immunohistochemically labelled using anti-LAP TGFbeta1 (latent form) and anti-TGFbeta1 (active form) antibodies, and fragments of tissue were subjected to Western blot analysis. No significant differences in LAP-TGFbeta1 expression were detected between specimens from control and hernia patients. However, significantly higher levels of active TGFbeta1 were detected in the TF of patients with direct hernia (P < 0.05). Age affected the expression of the growth factor in its active form, and significant differences emerged between direct hernias and controls/indirect hernias only in the younger age groups. Our findings indicate overexpression of the active form of TGFbeta1 in the TF of young patients with direct hernia. This overexpression reflects an attempt to counterbalance the enhanced matrix degradation process observed in these patients, identifying a subset of patients requiring the use of a prosthetic material for primary hernia repair.

FTIR evaluation of PGLA – Carbon fibres composite behaviour under ‘ in vivo’ conditions

Modification of resorbable polymers with carbon fibres makes it possible to work out multifunctional implants for use in bone surgery. This is due to biocompatibility of such composites as well as due to their suitable mechanical properties. In this study, the rate and the mechanism of resorbable lactide–glycolide copolymer (PGLA) as well as its composite with carbon fibre (PGLA + CF) degradation in vivo conditions have been tested. The influence of carbon fibres on the mechanism and rate of bone tissue regeneration has been also evaluated. Analysis has been based upon infrared spectroscopic studies (FTIR) as well as upon surface morphology examinations using scanning electron microscope (SEM). Results show that carbon fibres in PGLA + CF composite accelerate bone tissue regeneration and its reconstruction process starts on the fibre surface. FTIR investigations have proved different kinetics of polymer matrix degradation process for pure polymer and its composite with carbon fibre.

Histidine deficiency does not protect against aggrecan-induced arthritis

Increased numbers of mast cells are found in the synovial tissues and fluids of patients with rheumatoid arthritis, and at sites of cartilage erosion. Mast cell activation has been reported for a significant proportion of rheumatoid specimens. Because the mast cell contains potent mediators, including histamine, its potential contributions to the processes of inflammation and matrix degradation have recently become evident; thereafter, we investigated the potential protective effect of histamine deficiency against aggrecan-induced arthritis. To study the role of histamine in rheumatoid arthritis we investigated cartilage proteoglycan (aggrecan)-induced arthritis in histidine decarboxylase knockout (HDC-KO) mice, with complete lack of endogenously produced histamine. Aggrecan-induced arthritis was similar in HDC-KO and wild-type (WT) mice. Arthritis was even more severe in HDC-KO mice than in the WT animals 10 weeks following the immunization with aggrecan (arthritis score 1.2 ± 1.5 and 0 ± 0, respectively; P = 0.01). At later time points, arthritis scores were similar in both HDC-KO and WT mice. Since T-lymphocyte dysfunction has an important role in the pathogenesis of rheumatoid arthritis, next we investigated T-cell signal transduction and cytokine production in HDC-KO and WT mice. In the absence of histamine, elevated INFγ mRNA and protein levels of splenocytes (P < 0.001 and P = 0.001, respectively) were associated with a markedly increased (2.5-fold, P = 0.0009) nitric oxide (NO) production, compared with WT animals. Furthermore, histamine treatment decreased the NO production of splenocytes from both WT and HDC-KO mice (P = 0.001 and P = 0.0004, respectively). NO precursor (Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl) amino]diazen-1-ium-1,2-diolate-diethylenetriamine (NOC-18) elicited IFNγ production (P = 0.0002), suggesting the role of NO in regulating IFNγ synthesis. The cytoplasmic Ca2+ concentration of unstimulated T cells and the T-cell activation-induced Ca2+ signal were increased in T cells from the HDC-KO mice (P = 0.02 and P = 0.04, respectively), while the T-cell activation-induced CD3 internalization was similar in both HDC-KO and WT animals. Our present data indicate that histamine deficiency does not protect against aggrecan-induced arthritis. The Th1 cytokine pattern and increased NO production may both contribute to the sensitivity of HDC-KO mice to aggrecan-induced arthritis. Furthermore, our data indicate that histamine, in addition to its direct effects on T-lymphocyte function, regulates cytokine production and T-cell signal transduction through regulating NO production.

The role of matrix metalloproteinases in the oral environment

This review focuses specifically on matrix metalloproteinases (MMPs) and their role in physiological and pathological extracellular matrix (ECM) remodeling and degradation processes in the oral environment. A group of enzymes capable of degrading almost all ECM proteins, MMPs contribute to both normal and pathological tissue remodeling. The expression of different MMPs may be upregulated in pathological conditions such as inflammation and tumor invasion. The balance between activated MMPs and tissue inhibitors of metalloproteinases (TIMPs) controls the extent of ECM remodeling. Prior to mineralization, MMPs may participate in the organization of enamel and dentin organic matrix, or they may regulate mineralization by controlling the proteoglycan turnover. There is evidence indicating that MMPs could be involved in the etiology of enamel fluorosis and amelogenesis imperfecta. They seem to play a part in dentinal caries progression, since they have a crucial role in dentin collagen breakdown in caries lesions. MMPs have been identified in pulpal and periapical inflammation and are strongly correlated with periodontal diseases, since they are the major players in collagen breakdown during periodontal tissue destruction. The use of MMP inhibitors could help the prevention and treatment of many MMP-related oral diseases.

51 PROTEOMICS ANALYSIS OF PLACENTOMEGALY IN CLONED MICE

A variety of mammalian species have been cloned during the past few years. However, the success rate of somatic cell nuclear transfer in animals has been extremely low with many problems. Particularly, placentomegaly is a frequent finding in cloned mice and cattle (Wakayma et al. 1999 PNAS USA 96, 14 984–14 989; Niemann et al. 2000 Theriogenology 53, 21–34). To assess protein expression profile in the placentomagaly of cloned mice produced by nuclear transfer of embryonic stem cells, we have used global proteomics approach by 2-D gel electrophoresis and mass-spectrometry with the differential protein patterns using the 3 placentae of cloned mice and 4 normal mouse placentae. Proteins within isoelectric point range pH 4.0~9.0 and molecular weight range of 20–100 kDa separately were analyzed by 2-D gel electrophoresis with 3 replications of each sample. A total of approximately 3500 spots were detected 2-D gel. In the comparison of normal and cloned placenta samples, a total of 49 protein spots were expressed differentially, of which 28 spots were up-regulated proteins including alpha-fetoprotein, aspartyl aminopeptidase, placental lactogen 2, tissue inhibitor of metalloproteinase 2 (TIMP-2), etc., and 21 spots were down-regulated proteins including peroxiredoxin 6, creatine kinase, pre-B-cell colony-enhancing factor 1 (PBEF), etc. Eight spots could not be identified. One of differentially up-regulated proteins in cloned mouse placenta was identified as TIMP-2 protein that is related to extracellular matrix degradation and tissue remodeling processes. Western blot was performed with placental sample used in the 2-D gel electrophoresis analysis and normal mouse placenta samples on Days 11.5 to 18.5. Indeed, Western blot analysis confirmed a significant increase of TIMP-2 protein level in cloned mouse placenta compared with normal. The expression levels of TIMP-2 in normal mouse placenta were highest at the normal mid gestation (Day 13.5) and exhibited prominent decrease at late gestation period during normal pregnancy. However, the expression levels of TIMP-2 in placenta of cloned mice appeared to be similar to levels of mid gestation normal mouse placenta. And one of down-regulated protein in NT placenta was identified as PBEF protein that is known to be related to induction of spontaneous labor. PBEF protein level in cloned mice placenta was revealed to decrease remarkably compared with normal. The expression levels of PBEF in normal mice placenta exhibited a gradual decrease between Day 11.5 and Day 18.5 without complete depletion. However, the expression levels of PBEF in placenta of cloned mice appeared to be markedly lower than those of the same day normal placenta. In conclusion, abnormal expression of placental proteins associated with tissue remodeling and labor induction may be the cases of placentomegaly in cloned mice.

223 ABERRENT TIMP-2 GENE EXPRESSION IN CLONED BOVINE NEONATAL PLACENTA IS DUE TO ABNORMAL EPIGENETIC MODIFICATIONS

A global proteomics approach by 2-D gel electrophoresis and mass spectrometry was used to analyze the differential protein patterns of three placentae obtained after postnatal death of fetuses from SCNT of Korean Native cattle and three normal placentae obtained after birth of AI fetuses, as previously reported (Kim et al. 2004 Reprod. Fertil. Develop. 16, 145). One differentially up-regulated proteins in SCNT placenta was identified as TIMP-2 protein that is related to extracellular matrix degradation and tissue remodeling processes. To ensure that the identified protein was truly up-regulated in SCNT placenta, a small portion of the protein lysates were subjected to Western blotting with the antibodies against TIMP-2 and β-actin protein. Band images were scanned with a GT-6000 Scanner (Epson-Seiko, Suwa, Nagano, Japan) and densitometric analyses were performed using NIH Image (version 1.56). Proteins were normalized against the levels of β-actin protein. Indeed, Western blot analysis revealed a significant increase in TIMP-2 protein level (about 5-fold) in SCNT placenta compared with normal. Epigenetic programming of the genome by DNA methylation and histone modification ensures proper gene expression during development. To examine how the TIMP-2 gene was programmed to be active in SCNT placenta, we first investigated the status of DNA methylation in the promoter region of the TIMP-2 gene. Sodium bisulfite mapping revealed that most CpG sites in SCNT placenta cells were unmethylated in agreement with expression of TIMP-2 compared with those in normal placenta cells, suggesting that TIMP-2 gene programming by hypomethylation of CpG sites in the promoter region was responsible for the expression in SCNT placenta. We then examined histone modification of the nucleosome in the coding region of the TIMP-2 gene of SCNT placenta cells and normal placenta cells. Chromatin immunoprecipitation (ChIP) assay revealed that H3-K9/K14 acetylation of the TIMP-2 locus in SCNT placenta cells was about 2-fold higher than in normal placenta cells. Therefore, it is postulated that the SCNT placenta at the end of gestation seems to be unusual in tissue remodeling via improper expression of TIMP-2 by abnormal epigenetic modification, and that may affect placental abnormality such as enlarged and dysfunctional placentae as reported in cloned bovine and mouse.

Inhibitory Effect of Inflammatory Cytokines Production from Activated Mast Cells by Gamisopoonghwanghyul‐Tang

Rheumatoid arthritis (RA) is a chronic inflammatory disease and its exact cause and pathophysiological process remain unclear. Because the mast cell contains potent mediators, including multifunctional cytokines, its potential contributions to the processes of inflammation and matrix degradation have recently become evident. Gamisopoonghwanghyul‐tang (GSPHHT) has been used as a traditional Korean medicine for the treatment of RA. In this study, we investigated the effect of Gamisopoonghwanghyul‐tang (GSPHHT) on the production of inflammatory cytokines by activated human mast cell line HMC‐1 cells. When GSPHHT (1 mg/mL) was added, the production of tumor necrosis factor (TNF)‐α, interleukin (IL)‐1β, IL‐6, IL‐10 was inhibited by 36.3%, 36.3%, 30.8%, 48.7% respectively in phorbol 12‐myristate 13‐acetate plus calcium ionophore A23187‐stimulated HMC‐1 cells. However, the production of IL‐4 was significantly increased at 0.01 mg/mL. GSPHHT had no effect on TNF‐α mRNA expression. These results suggest that GSPHHT regulates production of inflammatory cytokines from activated mast cells.

Urokinase Plasminogen Activator Receptor and Soluble Matrix Metalloproteinase-9 in Acute Myeloid Leukemia Patients: A Possible Relation to Disease Invasion

Extracellular proteolytic enzymes of the urokinase-type plasminogen activator (uPA) and metalloproteinase (MMP) family play a crucial role in the matrix degradation and tissue remodeling process characteristic of malignant disorders. The receptor for urokinase plasminogen activator (uPAR) serves to localize and intensify the action of UPA and is expressed on the surface of malignant cells. Although the biological significance of MMP-9 and soluble urokinase receptor in growth and progression of lymphoid neoplasm is understood, its clinical significance in acute myeloid leukemia (AML) has not been fully elucidated. In this study, we determined the levels of soluble urokinase-type plasminogen activator receptor (suPAR), cellular uPAR and sMMP-9 in 43 newly diagnosed AML patients at diagnosis, before chemotherapy, and also studied 10 normal subjects served as a control group. After chemotherapy suPAR and MMP-9 were determined at remission and relapse. The levels of suPAR, cellular PAR were significantly higher (P=0.001, 0.001) and MMP-9 was significantly lower (P=0.001) in AML patients at diagnosis as compared to controls. suPAR and MMP-9 levels were significantly lower in AML patients who achieved complete remission (CR) as compared to those who did not (P=0.001 for both). Levels of suPAR and MMP-9 were significantly correlated to peripheral blood blast cells (r=0.88, P=0.001; r=0.65, P=0.001, respectively) and blast cell distribution ratio (BCDR, r=0.84, P=0.001; r=65, P=0.001, respectively). suPAR, cellular PAR and MMP-9 were significantly higher in patients with extramedullary infiltration as compared with those without (P=0.001, 0.001, <0.05). The suPAR, cellular uPAR, and MMP-9 levels were uneven in AML FAB subtypes being highest in M5(P<0.05 for all). MMP-9 and suPAR levels were correlated with the disease status. In AML survivors, MMP-9, cellular uPAR and suPAR were significantly lower as compared to non-survivors (P=0.001 for all).In conclusion, MMP-9 and suPAR levels might be used as a marker for disease activity and may contribute to blast cell dissemination. MMP-9 and suPAR may be target molecules in the strategy of treatment of AML.

Elevated plasma levels of TIMP-1 correlate with plasma suPAR/uPA in patients with chronic myeloproliferative disorders.

Chronic myeloproliferative disorders (MPD) are characterized by progressive remodelling of bone marrow stroma as evidenced by increased deposition of extracellular matrix proteins, neoangiogenesis and displacement of normal haematopoietic cells by fibrotic tissue. The family of metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) serve to facilitate and inhibit matrix degradation processes, respectively. In an attempt to investigate potential markers for bone marrow remodelling processes, we investigated plasma levels of total-, free- and complexed TIMP-1, TIMP-2, MMP-2 and MMP-9 in a patient cohort comprising 17 with myelofibrosis (MF), 17 with polycythaemia vera (PV), 15 with essential thrombocythaemia (ET), 1 with a transitional MPD and 30 controls. Compared with controls, total- (P < 0.0001) (median: 132.6 microg/L vs. 80.8 microg/L), free- (P < 0.0001) (median: 126.4 microg/L vs. 65.8 microg/L) and complexed TIMP-1 (P = 0.0009) (median: 17.7 microg/L vs. 10.7 microg/L) concentration was significantly higher in the patients. TIMP-1 was significantly correlated with plasma soluble urokinase plasminogen activator receptor (P = 0.003) and urokinase plasminogen activator (P < 0.0001), respectively, suggesting a common cellular origin. No statistical significant difference between TIMP-2 and MMP-2 levels was observed between patients and controls. Furthermore, a significant correlation between free TIMP-1 and TIMP-2 levels was detected (r = 0.56; P < 0.0001). Median MMP-9 concentration was significantly higher among PV patients compared with controls (P = 0.0015), and 41% of patients with PV (7/17) had MMP-9 values that were above the mean + 2SD of plasma MMP-9 levels found in controls. The ratio of total TIMP-1/MMP-9 was significantly higher in patients with MF compared with controls (P = 0.0004). These findings suggest that a disturbed TIMP-1/MMP ratio may reflect an imbalance of the extracellular homeostasis towards an increased matrix deposition promoting fibrosis.

Psychological stress impairs early wound repair following surgery.

Laboratory studies have demonstrated that psychological stress is associated with slower healing of small superficial wounds. The application of this finding to the clinical environment has not yet been undertaken. In order to do this, we investigated the relationship between psychological stress and wound repair in patients following routine surgery. Forty-seven adults with an inguinal hernia were given a standardized questionnaire assessing psychological stress and worry about the operation before undergoing open incision repair. Wound fluid was collected from 36 participants over the first 20-hour postoperative period. Wound healing was assessed by levels of interleukin-1, interleukin-6, and matrix metalloproteinase-9 in the fluid. Other outcome measures included patient self-reports of recovery, as well as cytokine response to lipopolysaccharide stimulation of peripheral blood. Greater preoperative perceived stress significantly predicted lower levels of interleukin-1 in the wound fluid (beta = -0.44, p = 0.03). Greater worry about the operation predicted lower levels of matrix metalloproteinase-9 in the wound fluid (beta = -0.38, p = 0.03) as well as a more painful (beta = 0.51, p = 0.002), poorer (beta = -0.36, p = 0.04), and slower recovery (beta = 0.43, p = 0.01). Psychological stress impairs the inflammatory response and matrix degradation processes in the wound immediately following surgery. This finding generalizes previous laboratory research to surgical patients and expands the known influence of stress to connective tissue matrix remodelling processes. These results suggest that in clinical practice, interventions to reduce the patient's psychological stress level may improve wound repair and recovery following surgery.

Human mast cell beta-tryptase is a gelatinase.

Remodeling of extracellular matrix is an important component in a variety of inflammatory disorders as well as in normal physiological processes such as wound healing and angiogenesis. Previous investigations have identified the various matrix metalloproteases, e.g., gelatinases A and B, as key players in the degradation of extracellular matrix under such conditions. Here we show that an additional enzyme, human mast cell beta-tryptase, has potent gelatin-degrading properties, indicating a potential contribution of this protease to matrix degradation. Human beta-tryptase was shown to degrade gelatin both in solution and during gelatin zymographic analysis. Further, beta-tryptase was shown to degrade partially denatured collagen type I. beta-Tryptase bound strongly to gelatin, forming high molecular weight complexes that were stable during SDS-PAGE. Mast cells store large amounts of preformed, active tryptase in their secretory granules. Considering the location of mast cells in connective tissues and the recently recognized role of mast cells in disorders in which connective tissue degradation is a key event, e.g., rheumatoid arthritis, it is thus likely that tryptase may contribute to extracellular matrix-degrading processes in vivo.