The circulating level of MMP-9 and its ratio to TIMP-1 as a predictor of severity in patients with community-acquired pneumonia

Associations of MMP9 polymorphism with the risk of severe pneumonia in a Southern Chinese children population

BACKGROUND

Severe pneumonia frequently causes irreversible sequelae and represents a major health burden for children under the age of 5. Matrix Metallopeptidase 9 (MMP9) is a zinc-dependent endopeptidase that is involved in various cellular processes. The correlation between MMP9 and the risk of severe childhood pneumonia remains unclear.

METHODS

Here we assemble a case-control cohort to study the association of genetic variants in MMP9 gene with severe childhood pneumonia susceptibility in a Southern Chinese population (1034 cases and 8426 controls).

RESULTS

Our results indicate that the allele G in rs3918262 SNP was significantly associated with an increased risk of severe pneumonia. Bioinformatic analyses by expression quantitative trait loci (eQTL), RegulomeDB and FORGEdb database analysis showed that rs3918262 SNP has potential regulatory effect on translational efficiency and protein level of MMP9 gene. Furthermore, MMP9 concentrations were significantly up-regulated in the bronchoalveolar lavages (BALs) of children with severe pneumonia.

CONCLUSION

In summary, our findings suggest that MMP9 is a novel predisposing gene for childhood pneumonia.

STAT3 Deficiency Alters the Macrophage Activation Pattern and Enhances Matrix Metalloproteinase 9 Expression during Staphylococcal Pneumonia

Staphylococcus aureus is a significant cause of morbidity and mortality in pulmonary infections. Patients with autosomal-dominant hyper-IgE syndrome due to STAT3 deficiency are particularly susceptible to acquiring staphylococcal pneumonia associated with lung tissue destruction. Because macrophages are involved in both pathogen defense and inflammation, we investigated the impact of murine myeloid STAT3 deficiency on the macrophage phenotype in vitro and on pathogen clearance and inflammation during murine staphylococcal pneumonia. Murine bone marrow-derived macrophages (BMDM) from STAT3 LysMCre+ knockout or Cre- wild-type littermate controls were challenged with S. aureus, LPS, IL-4, or vehicle control in vitro. Pro- and anti-inflammatory responses as well as polarization and activation markers were analyzed. Mice were infected intratracheally with S. aureus, bronchoalveolar lavage and lungs were harvested, and immunohistofluorescence was performed on lung sections. S. aureus infection of STAT3-deficient BMDM led to an increased proinflammatory cytokine release and to enhanced upregulation of costimulatory MHC class II and CD86. Murine myeloid STAT3 deficiency did not affect pathogen clearance in vitro or in vivo. Matrix metalloproteinase 9 was upregulated in Staphylococcus-treated STAT3-deficient BMDM and in lung tissues of STAT3 knockout mice infected with S. aureus. Moreover, the expression of miR-155 was increased. The enhanced inflammatory responses and upregulation of matrix metalloproteinase 9 and miR-155 expression in murine STAT3-deficient as compared with wild-type macrophages during S. aureus infections may contribute to tissue damage as observed in STAT3-deficient patients during staphylococcal pneumonia.

Circulating markers of neutrophil activation and lung injury in pediatric pneumonia in low-resource settings

Diagnostic biomarkers for childhood pneumonia could guide management and improve antibiotic stewardship in low-resource settings where chest x-ray (CXR) is not always available. In this cross-sectional study, we measured chitinase 3-like protein 1 (CHI3L1), surfactant protein D (SP-D), lipocalin-2 (LCN2), and tissue inhibitor of metalloproteinases-1 (TIMP-1) in Ugandan children under the age of five hospitalized with acute lower respiratory tract infection. We determined the association between biomarker levels and primary end-point pneumonia, indicated by CXR consolidation. We included 89 children (median age 11 months, 39% female). Primary endpoint pneumonia was present in 22 (25%). Clinical signs were similar in children with and without CXR consolidation. Broad-spectrum antibiotics (ceftriaxone) were administered in 83 (93%). Levels of CHI3L1, SP-D, LCN2 and TIMP-1 were higher in patients with primary end-point pneumonia compared to patients with normal CXR or other infiltrates. All markers were moderately accurate predictors of primary end-point pneumonia, with area under receiver operator characteristic curves of 0.66-0.70 (p<0.05 for all markers). The probability of CXR consolidation increased monotonically with the number of markers above cut-off. Among 28 patients (31%) in whom all four markers were below the cut-off, the likelihood ratio of CXR consolidation was 0.11 (95%CI 0.015 to 0.73). CHI3L1, SP-D, LCN2 and TIMP-1 were associated with CXR consolidation in children with clinical pneumonia in a low-resource setting. Combinations of quantitative biomarkers may be useful to safely withhold antibiotics in children with a low probability of bacterial infection.

The Role of Matrix Metalloproteinase in Inflammation with a Focus on Infectious Diseases

Matrix metalloproteinases (MMPs) are involved in extracellular matrix remodeling through the degradation of extracellular matrix components and are also involved in the inflammatory response by regulating the pro-inflammatory cytokines TNF-α and IL-1β. Dysregulation in the inflammatory response and changes in the extracellular matrix by MMPs are related to the development of various diseases including lung and cardiovascular diseases. Therefore, numerous studies have been conducted to understand the role of MMPs in disease pathogenesis. MMPs are involved in the pathogenesis of infectious diseases through a dysregulation of the activity and expression of MMPs. In this review, we discuss the role of MMPs in infectious diseases and inflammatory responses. Furthermore, we present the potential of MMPs as therapeutic targets in infectious diseases.

Elevated Plasma Levels of Matrix Metalloproteinase-3 and Tissue-Inhibitor of Matrix Metalloproteinases-1 Associate With Organ Dysfunction and Mortality in Sepsis

BACKGROUND

Matrix Metalloproteinases (MMP) respond to tissue damage during sepsis. Higher plasma concentrations of MMPs and the tissue-inhibitor of matrix metalloproteinases (TIMP) have been reported in sepsis compared with healthy controls. The objective of this study was to examine if plasma levels of MMP-3, MMP-9, and TIMP-1 associate with mortality and organ dysfunction during sepsis.

METHODS

We conducted a prospective cohort study of critically ill patients with sepsis adjudicated per Sepsis-3 criteria at a tertiary academic medical center. We measured plasma concentrations of MMP-3, MMP-9, and TIMP-1 on intensive care unit admission. We phenotyped the subjects for shock, acute respiratory distress syndrome (ARDS), acute kidney injury (AKI), and mortality at 30 days. We used logistic regression to test the associations between the MMPs and TIMP-1 with shock, ARDS, AKI, and mortality.

RESULTS

Higher plasma TIMP-1 levels were associated with shock (odds ratio [OR] 1.51 per log increase [95% CI 1.25, 1.83]), ARDS (OR 1.24 [95% CI 1.05, 1.46]), AKI (OR 1.18 [95% CI 1.01, 1.38]), and mortality (OR 1.20 [95% CI 1.05, 1.46]. Higher plasma MMP-3 concentrations were associated with shock (OR 1.40 [95% CI 1.12, 1.75]) and mortality (OR 1.24 [95% CI 1.03, 1.48]) whereas MMP-9 levels were not associated with outcomes. Higher plasma TIMP-1 to MMP-3 ratios were associated with shock (OR 1.41 [95% CI 1.15, 1.72], P = 0.02).

CONCLUSION

Elevated plasma concentrations of TIMP-1 associate with organ dysfunction and mortality in sepsis. Higher plasma levels of MMP-3 associate with shock and mortality. Plasma MMP and TIMP-1 may warrant further investigation as emerging sepsis theragnostic biomarkers.

A literature review of severity scores for adults with influenza or community-acquired pneumonia - implications for influenza vaccines and therapeutics

Influenza vaccination and antiviral therapeutics may attenuate disease, decreasing severity of illness in vaccinated and treated persons. Standardized assessment tools, definitions of disease severity, and clinical endpoints would support characterizing the attenuating effects of influenza vaccines and antivirals. We review potential clinical parameters and endpoints that may be useful for ordinal scales evaluating attenuating effects of influenza vaccines and antivirals in hospital-based studies. In studies of influenza and community-acquired pneumonia, common physiologic parameters that predicted outcomes such as mortality, ICU admission, complications, and duration of stay included vital signs (hypotension, tachypnea, fever, hypoxia), laboratory results (blood urea nitrogen, platelets, serum sodium), and radiographic findings of infiltrates or effusions. Ordinal scales based on these parameters may be useful endpoints for evaluating attenuating effects of influenza vaccines and therapeutics. Factors such as clinical and policy relevance, reproducibility, and specificity of measurements should be considered when creating a standardized ordinal scale for assessment.

Serum MMP-9 and SAA in the Diagnosis of Severe Pneumonia Caused by Radiotherapy of Esophageal Cancer

OBJECTIVE

To explore the relationship and diagnostic value of serum MMP-9 and SAA in severe pneumonia (sCAP) caused by radiotherapy of esophageal cancer.

METHODS

A total of 144 esophageal cancer patients who underwent radiotherapy in our hospital from April 2016 to February 2018 were collected. Among them, 58 patients without radiation pneumonitis (RP) were in the control group, 49 patients with grade 1∼2 RP were in the radiation group, and 37 patients with sCAP were in the severe group. The levels of serum MMP-9 and SAA in every group of patients were detected. The ROC curve was used to determine the diagnostic value of serum MMP-9 and SAA in the diagnosis of RP and sCAP. The correlation between serum MMP-9 and SAA and the patient's lung function indexes was analyzed, and the logistic single-factor and multivariate analyses were performed to analyze the factors of sCAP in esophageal cancer radiotherapy.

RESULTS

PaO2, FVC, and FEV1 decreased in RP and sCAP, and PaCO2, white blood cells, serum MMP-9, and SAA levels increased (P < 0.05); serum MMP-9 and SAA were negatively correlated with lung function (P < 0.05); the AUC of serum MMP-9 and SAA in RP was 0.833 and 0.823, respectively, and the AUC of the two combined diagnosis of RP was 0.919. The AUC of serum MMP-9 and SAA in sCAP was 0.809 and 0.797, respectively, and the AUC of both combined diagnosis of sCAP was 0.873; logistics multivariate analysis found that serum MMP-9, serum SAA, double lung V5, and V20 were independent risk factors for sCAP caused by radiotherapy for esophageal cancer (P < 0.05).

CONCLUSION

Serum MMP-9 and SAA increase in RP and sCAP and are negatively correlated with lung function in patients with pneumonia. They are independent risk factors for severe pneumonia caused by radiotherapy of esophageal cancer and have good diagnostic value.

The Potentials of Melatonin in the Prevention and Treatment of Bacterial Meningitis Disease

Bacterial meningitis (BM) is an acute infectious central nervous system (CNS) disease worldwide, occurring with 50% of the survivors left with a long-term serious sequela. Acute bacterial meningitis is more prevalent in resource-poor than resource-rich areas. The pathogenesis of BM involves complex mechanisms that are related to bacterial survival and multiplication in the bloodstream, increased permeability of blood-brain barrier (BBB), oxidative stress, and excessive inflammatory response in CNS. Considering drug-resistant bacteria increases the difficulty of meningitis treatment and the vaccine also has been limited to several serotypes, and the morbidity rate of BM still is very high. With recent development in neurology, there is promising progress for drug supplements of effectively preventing and treating BM. Several in vivo and in vitro studies have elaborated on understanding the significant mechanism of melatonin on BM. Melatonin is mainly secreted in the pineal gland and can cross the BBB. Melatonin and its metabolite have been reported as effective antioxidants and anti-inflammation, which are potentially useful as prevention and treatment therapy of BM. In bacterial meningitis, melatonin can play multiple protection effects in BM through various mechanisms, including immune response, antibacterial ability, the protection of BBB integrity, free radical scavenging, anti-inflammation, signaling pathways, and gut microbiome. This manuscript summarizes the major neuroprotective mechanisms of melatonin and explores the potential prevention and treatment approaches aimed at reducing morbidity and alleviating nerve injury of BM.

Plasma Matrix Metalloproteinase-9 and Tissue Inhibitor of Matrix Metalloproteinase-1 as Prognostic Biomarkers in Critically Ill Patients

Matrix metalloproteinase 9 (MMP-9) plays an important role in inflammatory and pathological processes by enabling the inflow of leukocytes to the site of infection or tissue damage. MMP-9 and tissue inhibitor of metalloproteinase 1 (TIMP-1) have been described as potential prognostic biomarkers in various clinical settings. The aim of the study was to evaluate the usefulness of plasma levels of MMP-9 and TIMP-1 as well as the MMP-9/ TIMP-1 ratio in predicting the outcome in patients admitted to the intensive care unit (ICU). The study included 56 critically ill patients with multiple organ failure. Plasma levels of MMP-9 and TIMP-1 were determined on hospitalization day 1, 2, 3 and 7. Nineteen (35.7%) patients died. The level of TIMP-1 was statistically significantly higher on day 1 and 7 of hospitalization in non-survivors, as compared to survivors (p=0.01). A statistically significant positive correlation was found between MMP-9 and TIMP-1. The MMP-9/TIMP-1 ratio was comparable in both groups during of observation (0.62 on day 1). The MMP-9/TIMP-1 ratio was positively correlated with the level of lactate and negatively correlated with platelet count. Likewise, TIMP-1 was positively correlated with the level of lactate. The level of MMP-9 was higher in the non-survivor group only on day 7 of observation. In conclusion, although TIMP-1 and MMP-9 concentrations were higher in non-survivors and the MMP-9/TIMP-1 ratio was related to some parameters of critical illness, further research is needed to verify whether they can serve as reliable biomarkers for early prognostication of ICU patients.

Plasma MMP2/TIMP4 Ratio at Follow-up Assessment Predicts Disease Progression of Idiopathic Pulmonary Arterial Hypertension

PURPOSE

Matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) are of particular interest in the remodeling processes of pulmonary hypertension. The aim of this study was to investigate MMP/TIMP ratios of selected biomarkers (MMP2, MMP9, TIMP1, TIMP4) at follow-up examination (V2) and their prognostic value in patients with idiopathic pulmonary arterial hypertension (iPAH).

METHODS

Blood samples were taken from iPAH patients during right heart catheterization at diagnosis (V1, from 2003 to 2012) and first follow-up examination (V2). MMP2, MMP9, TIMP1, and TIMP4 plasma levels at V2 were determined by ELISA. Coincident with sample collection hemodynamic, laboratory, and clinical parameters were acquired. Additionally, death and clinical worsening (CW) events were listed until July 2015.

RESULTS

MMP2/TIMP1 and MMP9/TIMP1 did not correlate with hemodynamic and clinical parameters. MMP2/TIMP4 showed a good correlation with mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance, estimated glomerular filtration rate (eGFR), and tricuspid annular plain systolic excursion (TAPSE). MMP9/TIMP4 shows good correlation with mPAP and eGFR. MMP2/TIMP4 showed significant results in the receiver operating characteristics analysis predicting death (AUC = 0.922; p = 0.005) and CW event (AUC = 0.818; p = 0.026). Patients above the cut-off values had a significantly higher probability to die or experience CW, respectively, estimated by log-rank test (p = 0.010 for death; p = 0.032 for CW).

CONCLUSIONS

MMP2/TIMP4 ratio was detected as a marker of disease severity and right ventricular function as well as a predictor for survival and time to clinical worsening and therefore might help for guidance of disease progression in iPAH patients at V2.

Cytokine Profile Associated with Selective Removal of Natural Anti-αGal Antibodies in a Sepsis Model in Gal-KO Mice

Selective depletion of natural anti-Galα1-3Galβ1-4GlcNAc (so-called anti-αGal) antibodies is achieved in α1,3-galactosyltransferase knockout (Gal-KO) mice by administration of the soluble glycoconjugate of αGal GAS914. This molecule removed up to 90% of natural circulating anti-αGal antibodies without causing unspecific production of cytokines in wild-type (CBA) and Gal-KO mice. However, the removal of anti-αGal antibodies in Gal-KO mice with GAS914 in the context of sepsis after cecal ligation and puncture (CLP) was associated with a significant increase in the production of leptin, CXLC1, CXLC13, and TIMP-1 cytokines compared to vehicle (PBS)-treated controls. Despite the current lack of understanding of the underlying mechanism, our data suggest a putative role of natural anti-αGal antibodies in the regulation of some cytokines during sepsis.

Convergence in the Epidemiology and Pathogenesis of COPD and Pneumonia

Chronic obstructive pulmonary disease (COPD) is one of the main causes of human mortalities globally after heart disease and stroke. There is increasing evidence of an aetiological association between COPD and pneumonia, the leading infectious cause of death globally in children under 5 years. In this review, we discuss the known risk factors of COPD that are also shared with pneumonia including smoking, air pollution, age and immune suppression. We review how lung pathology linked to a previous history of pneumonia may heighten susceptibility to the development of COPD in later life. Furthermore, we examine how specific aspects of COPD immunology could contribute to the manifestation of pneumonia. Based on the available evidence, a convergent relationship is becoming apparent with respect to the pathogenesis of COPD and pneumonia. This has implications for the management of both diseases, and the development of new interventions.

Elevated Plasma Matrix Metalloproteinase-9 and Its Correlations with Severity of Disease in Patients with Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) increases patient mortality and medical expenditure, and a real-time and reliable method for the rapid diagnosis of VAP may help reduce fatal complications. Matrix metalloproteinases-9 (MMP-9) is considered significant in the pathogenesis of lung inflammation and infection. Therefore, we examined its relationship with the clinical course of VAP. This retrospective observational study recruited 30 healthy volunteers, 12 patients who used mechanical ventilation without the development of VAP (hereafter, patients without VAP), and 30 patients with a clinical diagnosis of VAP (hereafter, patients with VAP). The activity and level of plasma MMP-9 were determined through a gelatin zymography assay and ELISA. Our results report that both plasma MMP-9 activity and concentration were significantly elevated in the acute stage of patients with VAP when compared with control group and patients without VAP (p < 0.001). Subsequently, the plasma MMP-9 of patients with VAP decreased significantly after antibiotic treatment. Furthermore, plasma MMP-9 concentration was positively correlated with the clinical pulmonary infection score (r = 0.409, p = 0.007), WBCs (r = 0.620, p < 0.001), and neutrophils counts (r = 0.335, p = 0.035). In addition, plasma MMP-9 is an excellent tool for recognizing VAP when the cutoff level is set to 92.62 ng/mL (AUC = 0.863, 95% CI = 0.761 to 0.932). In conclusions, we concluded that MMP-9 levels play a role in the development of VAP and might have the potential to be applied in the development of VAP therapies.

Population-based cohort study on the risk of pneumonia in patients with non-traumatic intracranial haemorrhage who use proton pump inhibitors

OBJECTIVES

This nationwide cohort study investigated the association between proton pump inhibitor (PPI) usage and the risk of pneumonia in patients with non-traumatic intracranial haemorrhage (ICH).

DESIGN

Nationwide population-based cohort study.

SETTING

Longitudinal Health Insurance Database 2010 (LHID2010) sampled from the Taiwan National Health Insurance Research Database.

PARTICIPANTS

4644 patients with non-traumatic ICH from 2010 to 2011 were identified. Patients aged <18 years and newly diagnosed with non-traumatic ICH complicated with pneumonia during the same admission period were excluded. A total of 2170 participants were eligible for the final analysis.

MAIN OUTCOME MEASURE

Patients using PPIs or not during the study period were tracked to identify the occurrence of any type of pneumonia.

RESULTS

The adjusted HR of the risk of pneumonia for ICH patients who used PPIs was 1.61 (95% CI 1.32 to 1.97, p<0.001). The risk of pneumonia was positively associated with the administration of PPIs. We observed a greater risk of pneumonia in patients who used PPIs than in those who did not. Moreover, we observed that the risk of pneumonia in patients who used PPIs was 2.60 and 2.04 (95% CI 2.01 to 3.38, p<0.001; 95% CI 1.34 to 3.10, p<0.001) greater than that in patients who did not use PPIs when the defined daily dose was <30 and 30-60, respectively.

CONCLUSIONS

The results of this study indicate that the use of PPIs in patients with non-traumatic ICH is associated with an increased risk of pneumonia, and the severity of this risk depends on the defined daily dose. Physicians should exercise caution when prescribing PPIs for patients with non-traumatic ICH.

Matrix metalloproteinases in pneumonia

Pneumonia is a worldwide infectious disease that is associated with significant morbidity and mortality and is the most common fatal infection acquired in hospitals. Despite advances in preventive strategies, such as antibiotic therapies and intensive care, the mortality rate still requires substantial improvement. Matrix metalloproteinases (MMPs) are a large family of zinc-dependent endopeptidases, which are known as the major enzymes responsible for the proteolytic degradation of proteinaceous components of the extracellular matrix (ECM). Although the main function of MMPs is the removal of the ECM during tissue resorption and progression of various diseases, MMPs also interact with multiple cytokines, participating in the pathology of infection and inflammation. This review presents a schematic overview of the different MMPs expressed in pneumonia. MMPs are key factors in the pathogenesis of various types of pneumonia, such as community-acquired pneumonia, hospital-acquired pneumonia, and ventilator-associated pneumonia. Here, we review the pathological roles of various MMPs in pneumonia.