MMP-9/BDNF ratio predicts more severe COVID-19 outcomes.

COVID-19 clinically manifests from asymptomatic to the critical range. Immune response provokes the pro-inflammatory interactions, which lead to the cytokines, reactive oxygen/nitrogen species, peptidases, and arachidonic acid metabolites enlargement and activation of coagulation components. Matrix metalloproteinases (MMPs) contribute to tissue destruction in the development of COVID-19. Due to the endothelial, systemic course of the disease, VEGF A participates actively in COVID-19 development, while neurotrophic and metabolic effects of BDNF recommends for the prediction of complications in COVID-19 patients. Searching for a marker that would improve and simplify the ranking in COVID-19, the study intended to evaluate the relationship of MMP-9 with VEGF A, BDNF, and MMP-8 with the COVID-19 severity. Upon admission to the hospital and before the therapy administration, 77 patients were classified into a mild, moderate, severe, or critical group. Due to the inflammatory stage in COVID-19, a comparison between groups showed related differences in leukocytes, neutrophils, lymphocytes, and platelets counts as anticipated. Only in seriously ill patients, there is a significant increase in the serum concentration of MMP-9, MMP-8, and VEGF A, while BDNF values did not show significant variations between groups. However, all those parameters positively correlated with each other. The ratio of MMP-9/BDNF markedly decreased in the severe and critically patients compared to the mild group. Testing the capability of this ratio to predict the COVID-19 stage by ROC curves, we found the MMP-9/BDNF could be a suitable marker for differentiating stages I/II (AUC 0.7597), stage I/III (AUC 0.9011), and stage I/IV (AUC 0.7727). Presented data describe for the first time the high-level systemic MMP-9/BDNF ratio in patients with COVID-19. This parameter could contribute to a more precise determination of the phase of the disease.

LncRNA TP73-AS1/miR-539/MMP-8 axis modulates M2 macrophage polarization in hepatocellular carcinoma via TGF-ß1 signaling.

PURPOSE: Our study aimed to study the role of lncRNA TP73-AS1/miR-539/MMP-8 axis in modulating M2 macrophage polarization in hepatocellular carcinoma (HCC). METHODS: The gene expression levels of TP73-AS1, miR-539 and MMP-8 were modified by transfection with the overexpression or knockdown vectors. The patient survival rate was analyzed using Kaplan-Meier method. The levels of TP73-AS1, miR-539, MMP-8 and M1/2 macrophage polarization markers were analyzed by qRT-PCR, western blot, and flow cytometry. The release of TGF-ß1 in the supernatant was determined by ELISA assay. The interaction between TP73-AS1, miR-539 and MMP-8 was analyzed by bioinformatics analysis and dual-luciferase reporter assays. Mouse xenograft model was further established to examine the therapeutic effects of the TP73-AS1 knockdown and miR-539 overexpression in vivo. RESULTS: We found TP73-AS1 and MMP-8 upregulation, and miR-539 downregulation in HCC tissues and cell lines. Lower TP73-AS1 and MMP-8 expressions and higher miR-539 expression were associated with higher survival rate of patients. M2-macrophage markers CD206, Arg-1 and CD163 were significantly upregulated in the tumor tissues. TP73-AS1 negatively and directly regulated miR-539 and knockdown of TP73-AS1 inhibited MMP-8 expression and M2 macrophage polarization. Also, overexpression of miR-539 suppressed M2 macrophage polarization by negatively regulating MMP-8. Furthermore, knockdown of MMP-8 also restrained M2 macrophage polarization via inhibiting TGF-ß1 signaling. We also found knockdown of TP73-AS1 or overexpression of miR-539 inhibited HCC tumor growth and M2 macrophage infiltration in vivo. CONCLUSION: Our study demonstrated lncRNA TP73-AS1 negatively regulated miR-539 to promote MMP-8 expression, which activated TGF-ß1 signaling to induce M2 macrophage polarization in HCC.

Temporomandibular joint damage in K/BxN arthritic mice.

Rheumatoid arthritis (RA) is an autoimmune disease affecting 1% of the world population and is characterized by chronic inflammation of the joints sometimes accompanied by extra-articular manifestations. K/BxN mice, originally described in 1996 as a model of polyarthritis, exhibit knee joint alterations. The aim of this study was to describe temporomandibular joint (TMJ) inflammation and damage in these mice. We used relevant imaging modalities, such as micro-magnetic resonance imaging (µMRI) and micro-computed tomography (µCT), as well as histology and immunofluorescence techniques to detect TMJ alterations in this mouse model. Histology and immunofluorescence for Col-I, Col-II, and aggrecan showed cartilage damage in the TMJ of K/BxN animals, which was also evidenced by µCT but was less pronounced than that seen in the knee joints. µMRI observations suggested an increased volume of the upper articular cavity, an indicator of an inflammatory process. Fibroblast-like synoviocytes (FLSs) isolated from the TMJ of K/BxN mice secreted inflammatory cytokines (IL-6 and IL-1ß) and expressed degradative mediators such as matrix metalloproteinases (MMPs). K/BxN mice represent an attractive model for describing and investigating spontaneous damage to the TMJ, a painful disorder in humans with an etiology that is still poorly understood.

A Prototype Antibody-based Biosensor for Measurement of Salivary MMP-8 in Periodontitis using Surface Acoustic Wave Technology.

Periodontitis is an economically important disease which is highly prevalent worldwide. Current diagnostic approaches are time-consuming and require interpretation of multiple aspects of clinical and radiographic assessment. Chair-side monitoring of inflammatory mediators of periodontitis could provide immediate information about disease activity, which can inform patient management. We aimed to develop a novel prototype biosensor to measure salivary matrix metalloproteinase-8 (MMP-8) using specific antibodies and surface acoustic wave (SAW) technology. The analytical performance of the prototype biosensor was compared to standard enzyme-linked immunosorbent assay (ELISA) using unstimulated saliva samples obtained from patients with periodontitis before and after non-surgical treatment (N = 58), patients with gingivitis (N = 54) and periodontally healthy volunteers (N = 65). Receiver operator characteristic (ROC) analysis for distinguishing periodontitis from health revealed an almost identical performance between the sensor and ELISA assays (area under curve values (AUC): ELISA 0.93; SAW 0.89). Furthermore, both analytical approaches yielded readouts which distinguished between heath, gingivitis and periodontitis, correlated identically with clinical measures of periodontal disease and recorded similar post-treatment decreases in salivary MMP-8 in periodontitis. The assay time for our prototype device is 20 minutes. The prototype SAW biosensor is a novel and rapid method of monitoring periodontitis which delivers similar analytical performance to conventional laboratory assays.

A Label-Free Quantitative Proteomic Analysis of Mouse Neutrophil Extracellular Trap Formation Induced by Streptococcus suis or Phorbol Myristate Acetate (PMA).

Streptococcus suis (S. suis) ranks among the five most important porcine pathogens worldwide and occasionally threatens human health, particularly in people who come into close contact with pigs or pork products. An S. suis infection induces the formation of neutrophil extracellular traps (NETs) in vitro and in vivo, and the NET structure plays an essential role in S. suis clearance. However, the signaling pathway by which S. suis induces NET formation remains to be elucidated. In the present study, we used a label-free quantitative proteomic analysis of mouse NET formation induced by S. suis or phorbol myristate acetate (PMA), a robust NET inducer. Greater than 50% of the differentially expressed proteins in neutrophils infected by S. suis showed similar changes as observed following PMA stimulation, and PKC, NADPH oxidase, and MPO were required for NET formation induced by both stimuli. Because PMA induced robust NET formation while S. suis (MOI = 2) induced only weak NET formation, the association between the inducer and NET formation was worth considering. Interestingly, proteins involved in peptidase activity showed significant differential changes in response to each inducer. Of these peptidases, MMP-8 expression was obviously decreased in response to PMA, but it was not significantly changed in response to S. suis. A subsequent study further confirmed that MMP-8 activity was inversely correlated with NET formation induced by both stimuli. Therefore, the present study provides potentially important information about the manner by which neutrophils responded to the inducers to form NETs.

Hypoxia increases neutrophil-driven matrix destruction after exposure to Mycobacterium tuberculosis.

The importance of neutrophils in the pathology of tuberculosis (TB) has been recently established. We demonstrated that TB lesions in man are hypoxic, but how neutrophils in hypoxia influence lung tissue damage is unknown. We investigated the effect of hypoxia on neutrophil-derived enzymes and tissue destruction in TB. Human neutrophils were stimulated with M. tuberculosis (M.tb) or conditioned media from M.tb-infected monocytes (CoMTB). Neutrophil matrix metalloproteinase-8/-9 and elastase secretion were analysed by luminex array and gelatin zymography, gene expression by qPCR and cell viability by flow cytometry. Matrix destruction was investigated by confocal microscopy and functional assays and neutrophil extracellular traps (NETs) by fluorescence assay. In hypoxia, neutrophil MMP-8 secretion and gene expression were up-regulated by CoMTB. MMP-9 activity and neutrophil elastase (NE) secretion were also increased in hypoxia. Hypoxia inhibited NET formation and both neutrophil apoptosis and necrosis after direct stimulation by M.tb. Hypoxia increased TB-dependent neutrophil-mediated matrix destruction of Type I collagen, gelatin and elastin, the main structural proteins of the human lung. Dimethyloxalylglycin (DMOG), which stabilizes hypoxia-inducible factor-1α, increased neutrophil MMP-8 and -9 secretion. Hypoxia in our cellular model of TB up-regulated pathways that increase neutrophil secretion of MMPs that are implicated in matrix destruction.

Neutrophil activation signature in juvenile idiopathic arthritis indicates the presence of low-density granulocytes.

Objective: JIA is an autoimmune, inflammatory disease with involvement of innate and adaptive immune responses. However, the role of neutrophils in JIA pathogenesis remains unclear. This study aimed to identify and validate neutrophil gene expression signatures in JIA using public microarray datasets and new clinical samples. Methods: Three suitable datasets were analysed by significance analysis of microarray and Ingenuity. Neutrophils and peripheral blood mononuclear cells (PBMCs) were isolated from a new cohort of JIA patients and healthy paediatric controls (HCs). Gene expression was validated using quantitative PCR. Serum concentrations of proteins were measured using ELISA. Low-density granulocytes (LDGs) in JIA and HC PBMCs were quantified by flow cytometry using forward/side-scatter properties. Results: Ingenuity identified transcriptional regulation (false discovery rate < 0.05) by G-CSF, GM-CSF and IL-8 along with expression of neutrophil granule protein genes including ELANE, MPO, MMP8 and MMP9 in datasets from JIA PBMCs. LDG counts were elevated in JIA compared with HCs (2.5% vs 1.4%; P = 0.007). Transcripts for MMP8 (P = 0.005), MPO (P = 0.0124) and Fcγ Receptor 1B (FCγR1B) (P = 0.0417) were significantly higher in JIA compared with HC neutrophils. MMP9 protein levels were lower in systemic JIA patient sera [355.95 ng/ml (s.d. 250.03)] compared with HCs [675.41 ng/ml (s.d. 181.17); P = 0.007], but levels of elastase, MPO and MMP8 were not significantly different. Conclusion: LDGs are elevated in JIA and contribute to the transcriptomic profile of JIA PBMCs. JIA neutrophils express higher levels of MMP8 and FCGR1B, which may be implicated in disease pathology through the release of proteases and reactive oxygen metabolites, causing systemic inflammation and damage to joints.

Suppression of neuroinflammation by matrix metalloproteinase-8 inhibitor in aged normal and LRRK2 G2019S Parkinson's disease model mice challenged with lipopolysaccharide.

Microglial priming is caused by aging and neurodegenerative diseases, and is characterized by an exaggerated microglial inflammatory response to secondary and sub-threshold challenges. In the present study, we examined the effects of the matrix metalloproteinase-8 (MMP-8) inhibitor (M8I) on the brain of aged normal and leucine-rich repeat kinase 2 (LRRK2) G2019S Parkinson's disease (PD) model mice systemically stimulated with lipopolysaccharide (LPS). The results indicated that Iba-1 positive microglia and GFAP-positive astrocytes, which were increased by LPS, significantly decreased by M8I in aged normal and PD model mice. M8I also decreased the expression of pro-inflammatory markers in the hippocampus and midbrain of aged normal and PD model mice challenged with LPS, while it also improved the motor coordination of aged normal mice after LPS challenge in rotor rod test and the general crossing locomotor activities of LPS-treated LRRK2G2019S PD mice after LPS challenge in open field test. To assess the effects of M8I in an in vitro priming model, BV2 microglia were pretreated with macrophage colony-stimulating factor (CSF)-1 or interleukin (IL)-34, and subsequently stimulated with LPS or polyinosinic-polycytidylic acid (poly[I:C]). M8I inhibited the LPS- or poly(I:C)-induced production of the tumor necrosis factor-α and nitric oxide, alone or in combination with CSF-1 or IL-34. Collectively, the data suggested that M8I has a therapeutic potential in treating neurodegenerative diseases that are aggravated by systemic inflammation.

Matrix metalloproteinase-8 activity in gingival crevicular fluid: development of a novel assay.

BACKGROUND AND OBJECTIVE: The matrix metalloproteinases (MMPs) play a role in regulating turnover and metabolism of connective tissues in health but they have also been implicated in a wide variety of pathological conditions, including periodontal disease. MMP-8 has been extensively studied in periodontal health and disease using ELISA, although this technique is limited by its inability to determine enzyme activity. The aim was to develop an assay specifically to measure MMP-8 activity and to demonstrate its use in the analysis of gingival crevicular fluid samples. MATERIAL AND METHODS: A specific antibody was used to coat black 96-well microtitre plates to capture MMP-8 selectively. The activity of bound MMP-8 was measured using a fluorogenic substrate. Gingival crevicular fluid samples, from healthy and periodontally diseased sites, were collected using PerioPaper strips and tested for MMP-8 activity. RESULTS: Significantly higher MMP-8 activity was demonstrated in gingival crevicular fluid from periodontally diseased sites compared with healthy sites that exhibited basal or no MMP-8 activity. No cross-reactivity with other MMPs was noted. CONCLUSION: We show, for the first time, that MMP-8 activity can be specifically detected and quantified in gingival crevicular fluid samples. Measurement of MMP-8 activity could prove to be useful in monitoring periodontal disease progression.

Vaginal Inflammation: Association between Leukocyte Concentration and Levels of Immune Mediators.

PROBLEM: A wide variety of mediators are involved in inflammatory processes. However, the identity of those participating in vaginal immune responses has not been established. We correlated extracellular matrix metalloproteinase inducer (EMMPRIN), matrix metalloproteinase-8 (MMP-8), hyaluronan (HA), hyaluronidase-1 (Hyal-1), human ß-defensin-2 (hBD2), and neutrophil gelatinase-associated lipocalin (NGAL) concentrations with the extent of leukocyte infiltration into the vagina and suggest their participation in vaginal inflammation. METHODS OF STUDY: Vaginal fluid was obtained from 233 women seen at the outpatient clinic in the Department of Obstetrics and Gynecology at Campinas University, Brazil. The magnitude of vaginal inflammation was determined by the leukocyte count on vaginal smears and categorized as no inflammation (0 leukocytes/field), moderate inflammation (1-4 leukocytes/field), and intense inflammation (>4 leukocytes/field). Concentrations of EMMPRIN, MMP-8, HA, Hyal-1, hBD2, and NGAL were determined in vaginal fluid by ELISA. RESULTS: EMMPRIN, MMP-8, HA, hBD2, and NGAL concentration increased with elevated leukocyte numbers (P < 0.05), while Hyal-1 did not. EMMPRIN concentrations were correlated with HA and MMP-8 levels. CONCLUSION: EMMPRIN, MMP-8, HA, ß-defensin, and NGAL are elevated in women with vaginal inflammation.

Possible implications of Ni(II) on oral IL-1ß-induced inflammatory processes.

OBJECTIVES: Nickel (Ni) is one of the main metal elements in orthodontic and prosthetic devices. Different effects of Ni are described ranging from an induction of local inflammation to allergy and cancerous/mutagenic properties. Inflammatory reactions are frequently observed in the oral cavity, but the interrelationship of Ni with those events is still unknown. Therefore, we focused on the impact of Ni on inflammation in vitro. METHODS: In accordance to previous immersion tests of our lab, human gingival fibroblasts (HGFs) (n=6) were exposed to a pro-inflammatory environment using interleukin-1 beta (IL-1ß) and additionally stimulated with different Ni(II) concentrations (400 and 4000ng/ml). At varying time points the expression of pro- and anti-inflammatory as well as matrix degeneration proteins, i.e. MMPs, were analyzed. Furthermore, proliferation assays, wound healing tests and the detection of NF-κB activation were conducted. Unstimulated HGFs served as control. RESULTS: Our experiments showed that low clinical average Ni(II) levels did not alter pro-inflammatory cytokines significantly compared to control (p>0.05). Instead, a 10-fold higher dose up-regulated these mediators significantly in a time-dependent manner (p<0.01). This was even more pronounced combining both Ni(II) concentrations with an inflammatory condition (p<0.001), MMP expressions were in line with our findings (p<0.001). The mRNA data were supported by proliferation and wound closure assays (p<0.001). However, the combination of both stimuli induced contradictory results. Analyzing NF-κB activation revealed that our results may be in part attributed to NF-κB. SIGNIFICANCE: Our in vitro study implicated that Ni(II) has various modifying effects on IL-1ß-induced inflammatory processes depending on the concentration.

Matrix metalloproteinase-8 plays a pivotal role in neuroinflammation by modulating TNF-α activation.

Matrix metalloproteinases (MMPs) play important roles in normal brain development and synaptic plasticity, although aberrant expression of MMPs leads to brain damage, including blood-brain barrier disruption, inflammation, demyelination, and neuronal cell death. In this article, we report that MMP-8 is upregulated in LPS-stimulated BV2 microglial cells and primary cultured microglia, and treatment of MMP-8 inhibitor (M8I) or MMP-8 short hairpin RNA suppresses proinflammatory molecules, particularly TNF-α secretion. Subsequent experiments showed that MMP-8 exhibits TNF-α-converting enzyme (TACE) activity by cleaving the prodomain of TNF-α (A(74)/Q(75), A(76)/V(77) residues) and, furthermore, that M8I inhibits TACE activity more efficiently than TAPI-0, a general TACE inhibitor. Biochemical analysis of the underlying anti-inflammatory mechanisms of M8I revealed that it inhibits MAPK phosphorylation, NF-κB/AP-1 activity, and reactive oxygen species production. Further support for the proinflammatory role of microglial MMP-8 was obtained from an in vivo animal model of neuroinflammatory disorder. MMP-8 is upregulated in septic conditions, particularly in microglia. Administration of M8I or MMP-8 short hairpin RNA significantly inhibits microglial activation and expression/secretion of TNF-α in brain tissue, serum, and cerebrospinal fluid of LPS-induced septic mice. These results demonstrate that MMP-8 critically mediates microglial activation by modulating TNF-α activity, which may explain neuroinflammation in septic mouse brain.

A natural bacterial-derived product, the metalloprotease arazyme, inhibits metastatic murine melanoma by inducing MMP-8 cross-reactive antibodies.

The increased incidence, high rates of mortality and few effective means of treatment of malignant melanoma, stimulate the search for new anti-tumor agents and therapeutic targets to control this deadly metastatic disease. In the present work the antitumor effect of arazyme, a natural bacterial-derived metalloprotease secreted by Serratia proteomaculans, was investigated. Arazyme significantly reduced the number of pulmonary metastatic nodules after intravenous inoculation of B16F10 melanoma cells in syngeneic mice. In vitro, the enzyme showed a dose-dependent cytostatic effect in human and murine tumor cells, and this effect was associated to the proteolytic activity of arazyme, reducing the CD44 expression at the cell surface, and also reducing in vitro adhesion and in vitro/in vivo invasion of these cells. Arazyme treatment or immunization induced the production of protease-specific IgG that cross-reacted with melanoma MMP-8. In vitro, this antibody was cytotoxic to tumor cells, an effect increased by complement. In vivo, arazyme-specific IgG inhibited melanoma lung metastasis. We suggest that the antitumor activity of arazyme in a preclinical model may be due to a direct cytostatic activity of the protease in combination with the elicited anti-protease antibody, which cross-reacts with MMP-8 produced by tumor cells. Our results show that the bacterial metalloprotease arazyme is a promising novel antitumor chemotherapeutic agent.

Neutrophil apoptosis is associated with loss of signal regulatory protein alpha (SIRPα) from the cell surface.

Cells of the innate immune system, including monocytes, macrophages, and neutrophils, play a major role in the development of inflammatory diseases. During inflammation, large numbers of neutrophils are recruited from the blood and subsequently undergo apoptosis, which involves changes in the cell surface expression of a number of receptors. Neutrophils express the Ig superfamily member, SIRPα, which is a receptor involved in regulating cell adhesion and migration. As apoptotic neutrophils down-regulate their capacity for adhesion and migration, we here investigated whether neutrophil expression of SIRPα was affected during apoptosis. We found that apoptotic neutrophils lost SIRPα from their cell surface with kinetics similar to the loss of CD16. The majority of neutrophils with reduced SIRPα also expressed PS on their surface, and the loss of the receptor was reduced proportional to the reduction of apoptosis by caspase inhibitors during Fas-induced apoptosis but less so during spontaneous apoptosis. Neutrophil loss of SIRPα or CD16 was inhibited by the protease inhibitor TAPI-2, as well as specific inhibitors of MMP3 or -8, suggesting that proteolytic mechanisms were involved. Finally, SIRPα was also found on smaller membrane vesicles released from the cells during apoptosis. Our data suggest that neutrophils reduce their SIRPα expression during apoptosis, which may be part of the functional down-regulation seen in apoptotic neutrophils.

Development and validation of novel enzyme activity methods to assess inhibition of matrix metalloproteinases (MMPs) in human serum by antibodies against enzyme therapeutics.

This paper summarizes the development and validation of five enzyme activity methods to assess the specific inhibition of human endogenous matrix metalloproteinases MMP-1 (interstitial collagenase), MMP-2 (gelatinase A), MMP-3 (stromelysin 1), MMP-8 (collagenase 2) and MMP-13 (collagenase 3) by anti-Collagenase Clostridium histolyticum (CCH) antibodies in human serum. These MMPs are of interest since antibodies against a therapeutic enzyme may cross-react with, and inactivate, the MMPs. The validated methods utilize spiked exogenous individual MMPs added to serum to determine if the serum inhibits MMP enzyme activity. Factors evaluated and optimized during development include pH, reaction time and temperature, inhibitor concentration for the positive control, and substrate and serum concentration. Characteristics established during validation for each MMP activity inhibition method included intra- and inter-assay precision and recovery, recovery in the pooled normal human serum samples, bench-top stability at room temperature and on wet ice, and assay cut-point determination. Precision results ranged from ~1 to 12% CV, recoveries of the activities of the exogenous MMPs ranged from ~84 to 90% and cut-point values ranged from 67 to 91%.

Invariant natural killer T-cell-deficient mice display increased CCl4 -induced hepatitis associated with CXCL1 over-expression and neutrophil infiltration.

Invariant natural killer T (iNKT) cells are involved in the intrahepatic immune response and in hepatitis. In particular, iNKT lymphocytes are responsible for hepatocyte death in concanavalin A-induced hepatitis in mice. We examined the role of iNKT cells in acute hepatitis induced by a hepatotoxic agent, carbon tetrachloride (CCl(4) ). WT and iNKT cell-deficient (Jα18(-/-) ) mice were challenged with a single dose of 2.4 g/kg CCl(4) and both hepatic physiopathology and immune responses were studied. Plasma alanine and aspartate amino-transferase levels were significantly higher in Jα18(-/-) mice than in WT mice two days after CCl(4) administration. Chemokine CXCL1/keratinocyte-derived chemokine (KC) and MMP-8 were significantly higher in iNKT cell-deficient mice than in control mice. The more severe liver injury in Jα18(-/-) mice was associated with greater leukocyte infiltrate, which was enriched in neutrophils (CD11b(+) CD11c(-) Gr-1(+) cells), in agreement with CXCL1/KC and MMP-8 levels. Complementary experiments with NK-depleted animals indicate a minor role for NK cells in the liver damage found in iNKT-deficient mice. Thus, unlike for ConA-induced hepatitis, we report that iNKT cells protect the liver against acute hepatitis induced by CCl(4) and limit neutrophil infiltration.

Collagenase-2 (MMP-8) as a point-of-care biomarker in periodontitis and cardiovascular diseases. Therapeutic response to non-antimicrobial properties of tetracyclines.

Neutrophil collagenase or collagenase-2 (matrix metalloproteinase [MMP]-8) belongs to the collagenase subgroup of the MMP superfamily of calcium- and zinc-dependent neutral proteinases. MMP-8 is catalytically the most competent proteinase to initiate type I collagen and extracellular matrix degradation associated with periodontal and peri-implant tissue destruction leading to tooth and dental implant loss. Regarding cardiovascular diseases, pathologically excessive MMP-8 has been implicated in atherosclerotic plaque destabilization and rupture probably through its proteolytic ability to thin the protecting collagenous fibrous cap lining coronary and other arteries. During the initiation and course of inflammatory responses in periodontitis, peri-implantitis and cardiovascular diseases, proinflammatory mediators including especially MMP-8 are up-regulated not only in affected tissues but also in the secreted, disease-affected, oral fluids (gingival crevicular fluid [GCF], peri-implant sulcular fluid [PISF], mouthrinse and saliva) as well as in serum and plasma. Regarding periodontitis, peri-implantitis and cardiovascular diseases, the oral fluid and serum MMP-8 analysis has proven to be a sensitive and an objective biomarker as an indicator of health, pathologic processes and pharmacologic response to therapeutic intervention including doxycycline medication as an MMP inhibitor. Oral fluids, i.e., GCF, PISF, mouthrinse and saliva are easily and non-invasively collected for the site- and patient-specific diagnostic analysis in periodontitis and peri-implantitis, whereas serum and/or plasma sample collection is required for diagnosis and monitoring of cardiovascular diseases. Research in periodontology and cardiology has identified a need for the development of innovative point-of-care diagnostic tests for MMP-8. We summarize and review the recent studies on these topics.

Matrix metalloproteinase-8 deficiency increases joint inflammation and bone erosion in the K/BxN serum-transfer arthritis model.

INTRODUCTION: Rheumatoid arthritis is an autoimmune disease in which joint inflammation leads to progressive cartilage and bone erosion. Matrix metalloproteinases (MMPs) implicated in homeostasis of the extracellular matrix play a central role in cartilage degradation. However, the role of specific MMPs in arthritis pathogenesis is largely unknown. The aim of the present study was to investigate the role of Mmp-8 (collagenase-2) in an arthritis model. METHODS: Arthritis was induced in Mmp8-deficient and wildtype mice by K/BxN serum transfer. Arthritis severity was measured by a clinical index and ankle sections were scored for synovial inflammation, cartilage damage and bone erosion. cDNA microarray analysis, real-time PCR and western blot were performed to identify differential changes in gene expression between mice lacking Mmp8 and controls. RESULTS: Mmp8 deficiency increased the severity of arthritis, although the incidence of disease was similar in control and deficient mice. Increased clinical score was associated with exacerbated synovial inflammation and bone erosion. We also found that the absence of Mmp8 led to increased expression of IL-1ß, pentraxin-3 (PTX3) and prokineticin receptor 2 (PROKR2) in arthritic mice joints. CONCLUSIONS: Lack of Mmp-8 is accompanied by exacerbated synovial inflammation and bone erosion in the K/BxN serum-transfer arthritis model, indicating that this Mmp has a protective role in arthritis.

Gene expression changes associated with resistance to intravenous corticosteroid therapy in children with severe ulcerative colitis.

BACKGROUND AND AIMS: Microarray analysis of RNA expression allows gross examination of pathways operative in inflammation. We aimed to determine whether genes expressed in whole blood early following initiation of intravenous corticosteroid treatment can be associated with response. METHODS: From a prospectively accrued cohort of 128 pediatric patients hospitalized for intravenous corticosteroid treatment of severe UC, we selected for analysis 20 corticosteroid responsive (hospital discharge or PUCAI ≤45 by day 5) and 20 corticosteroid resistant patients (need for second line medical therapy or colectomy, or PUCAI >45 by day 5). Total RNA was extracted from blood samples collected on day 3 of intravenous corticosteroid therapy. The eluted transcriptomes were quantified on Affymetrix Human Gene 1.0 ST arrays. The data was analysed by the local-pooled error method for discovery of differential gene expression and false discovery rate correction was applied to adjust for multiple comparisons. RESULTS: A total of 41 genes differentially expressed between responders and non-responders were detected with statistical significance. Two of these genes, CEACAM1 and MMP8, possibly inhibited by methylprednisolone through IL8, were both found to be over-expressed in non-responsive patients. ABCC4 (MRP4) as a member of the multi-drug resistance superfamily was a novel candidate gene for corticosteroid resistance. The expression pattern of a cluster of 10 genes selected from the 41 significant hits were able to classify the patients with 80% sensitivity and 80% specificity. CONCLUSIONS: Elevated expression of several genes involved in inflammatory pathways was associated with resistance to intravenous corticosteroid therapy early in the course of treatment. Gene expression profiles may be useful to classify resistance to intravenous corticosteroids in children with severe UC and assist with clinical management decisions.

Elevated MMP-8 and decreased myeloperoxidase concentrations associate significantly with the risk for peripheral atherosclerosis disease and abdominal aortic aneurysm.

Matrix metalloproteinases are responsible for degradation and remodelling of extracellular matrix and exert important roles in initiation and progression of inflammatory diseases. We aimed to examine the role of Matrix metalloproteinases (MMPs) and their regulators in degenerative arterial diseases. Serum samples were collected from patients with arterial disease (n = 126), who underwent surgery because of symptomatic aorto-occlusive disease (AOD, n = 18), carotid artery stenosis (n = 67) or abdominal arotic aneurysm (n = 41). Serum MMP-1, MMP-8, MMP-13, TIMP-1, myeloperoxidase (MPO) and neutrophil elastase (HNE) concentrations were determined by ELISA, and the molar ratio of MMP-8 and TIMP-1 was calculated. To get reference values, the determinations were done on samples of healthy blood donors (n = 100). In univariate analyses, the patients had higher MMP-8 (P < 0.001), TIMP-1 (P = 0.045), and MMP-8/TIMP-1 (P < 0.001), and lower MPO (P < 0.001) when compared with the blood donors. All three subgroups had higher MMP-8 (P < 0.001) and MMP-8/TIMP-1 (P < 0.001), and lower MPO (P < 0.01, except AOD) levels when compared with the references. In multiple logistic regression analyses, the male gender (P < 0.01), age (P < 0.001), elevated MMP-8 (P < 0.001) and decreased MPO (P < 0.001) concentrations associated significantly with the risk for arterial disease, and provided an area under curve (AUC) of 0.97 in the Receiver operating characteristics analyses. In multiple linear regression analyses, HNE correlated with both MMP-8 (P < 0.001) and MPO (P = 0.008) concentrations. Combination of high MMP-8 and low MPO level in serum eventually reflecting selectively modified neutrophil degranulation may indicate increased risk for arterial disease.