Comparison of levels of serum matrix metalloproteinase-9 in patients with acute myocardial infarction versus unstable angina pectoris versus stable angina pectoris

The impact of vildagliptin as an add-on therapy on matrix metalloproteinase-14 levels, liver stiffness and subclinical atherosclerosis in adolescents with type 1 diabetes and non-alcoholic steatohepatitis: A randomized controlled trial

AIM

Many patients with type 1 diabetes mellitus (T1DM) met the histological criteria for non-alcoholic steatohepatitis (NASH), which leads to cardiovascular disease morbidity and mortality. Matrix metalloproteinase-14 (MMP-14) is involved in cardiovascular disease and atherosclerosis.

OBJECTIVES

To assess the impact of oral dipeptidyl peptidase-4 inhibitor, vildagliptin, as adjunctive therapy on NASH in adolescents with T1DM and its effect on glycaemic control, MMP-14 levels and carotid intima media thickness (CIMT).

METHODS

Sixty adolescents with T1DM and NASH were randomly assigned to receive oral vildagliptin (50 mg once daily) for 6 months or not. Glycated haemoglobin, lipid profile, hepatic steatosis index, triglyceride glucose (TyG) index and MMP-14 levels were assessed. Transient elastography with controlled attenuation parameter (CAP) was performed together with measuring CIMT.

RESULTS

By transient elastography, 12 (20%) patients with T1DM with NASH had elevated liver stiffness ≥7 kPa (F2 stage or higher). Baseline MMP-14 was positively correlated to insulin dose (p = 0.016), triglycerides and TyG index, CIMT, liver stiffness and CAP levels among the studied patients (p < 0.001 for all). After 6 months, patients with T1DM on vildagliptin therapy had significantly lower glycated haemoglobin, lipid profile, hepatic steatosis index and TyG index, as well as MMP-14 (p < 0.001). CIMT, liver stiffness and CAP were significantly decreased post-therapy compared with baseline levels and compared with the control group (p < 0.001). Vildagliptin was safe and well-tolerated.

CONCLUSIONS

Administration of vildagliptin for adolescents with T1DM and NASH improved glycaemic control, dyslipidaemia and MMP-14 levels and decreased liver stiffness and CIMT; hence, reducing subclinical atherosclerosis and disease progression.

PCSK9 expression in fibrous cap possesses a marker for rupture in advanced plaque

BACKGROUND

To date, PCSK9 inhibitors are well known for eliminating cardiac and cerebral artery ischemia events by lowering the serum lipid level. However, the pathophysiological value of in-plaque PCSK9 expression is still unclear.

METHODS

Advanced plaques removed by carotid endarterectomy were sectioned and stained to identify the PCSK9 expression pattern and its co-expression with rupture-relevant markers. To investigate the correlation of PCSK9 expression with regional blood shear flow, hemodynamic characteristics were analyzed using computational fluid dynamics, and representative parameters were compared between PCSK9 positive and negative staining plaques. To explore this phenomenon in vitro, human aortic vascular smooth muscle cells were used to overexpress and knock down PCSK9. The impacts of PCSK9 modulations on mechanical sensor activity were testified by western blot and immunofluorescence. Real-time polymerase chain reaction was used to evaluate the transcription levels of downstream rupture-prone effectors.

RESULTS

PCSK9 distribution in plaque preferred cap and shoulder regions, residing predominantly in smooth muscle actin-positive cells. Cap PCSK9 expression correlated with fibrous cap thickness negatively and co-expressed with MMP-9, both pointing to the direction of plaque rupture. A hemodynamic profile indicated a rupture-prone feature of cap PCSK9 expression. In vitro, overexpression and knockdown of PCSK9 in human aortic vascular smooth muscle cells has positive modulation on mechanical sensor Yes-associated protein 1 (YAP) activity and transcription levels of its downstream rupture-prone effectors. Serial section staining verified in situ colocalization among PCSK9, YAP, and downstream effectors.

CONCLUSIONS

Cap PCSK9 possesses a biomarker for rupture risk, and its modulation may lead to a novel biomechanical angle for plaque interventions.

Lipoprotein(a) and Low-Molecular-Weight Apo(a) Phenotype as Determinants of New Cardiovascular Events in Patients with Premature Coronary Heart Disease

BACKGROUND

Lipoprotein(a) (Lp(a)) is a genetic risk factor of atherosclerotic cardiovascular diseases (ASCVDs). Proprotein convertase subtilisin/kexin type 9 (PCSK9) is related to vascular inflammation and detected in atherosclerotic plaques. A temporary increase in the circulating concentration of PCSK9 and Lp(a) was shown in patients with myocardial infarction (MI). The aim of this study was to evaluate the role of the apo(a) phenotype and the Lp(a) concentration as well as its complex with PCSK9 in the development of cardiac events and MI in patients with a premature manifestation of coronary heart disease (CHD).

METHODS

In a prospective study with retrospective data collection, we included 116 patients with premature CHD who were followed for a median of 14 years. The medical history and information on cardiovascular events after an initial exam as well as data on the levels of lipids, Lp(a), PCSK9, PCSK9-Lp(a) complex, and apo(a) phenotype were obtained.

RESULTS

The patients were divided into two groups depending on the presence of a low- (LMW, n = 52) or high-molecular weight (HMW, n = 64) apo(a) phenotype. LMW apo(a) phenotype (odds ratio 2.3 (1.1 to 4.8), p = 0.03), but not elevated Lp(a) (1.9 (0.8-4.6), p = 0.13), was an independent predictor for the development of MI after adjustment for sex, age of CHD debut, initial lipids levels, and lipid-lowering treatment. The apo(a) phenotype also determined the relationship between Lp(a) and PCSK9 concentrations. The level of the PCSK9-Lp(a) complex was higher in LMW apo(a) patients.

CONCLUSION

The LMW apo(a) phenotype is a risk factor for non-fatal MI in a long-term prospective follow-up of patients with premature CHD, and this link could be mediated via PCSK9.

Single-cell profiling reveals inflammatory polarization of human carotid versus femoral plaque leukocytes

Femoral atherosclerotic plaques are less inflammatory than carotid plaques histologically, but limited cell-level data exist regarding comparative immune landscapes and polarization at these sites. We investigated intraplaque leukocyte phenotypes and transcriptional polarization in 49 patients undergoing femoral (n = 23) or carotid (n = 26) endarterectomy using single-cell RNA-Seq (scRNA-Seq; n = 13), flow cytometry (n = 24), and IHC (n = 12). Comparative scRNA-Seq of CD45+-selected leukocytes from femoral (n = 9; 35,265 cells) and carotid (n = 4; 30,655 cells) plaque revealed distinct transcriptional profiles. Inflammatory foam cell-like macrophages and monocytes comprised higher proportions of myeloid cells in carotid plaques, whereas noninflammatory foam cell-like macrophages and LYVE1-overexpressing macrophages comprised higher proportions of myeloid cells in femoral plaque (P < 0.001 for all). A significant comparative excess of CCR2+ macrophages in carotid versus plaque was observed by flow cytometry in a separate validation cohort. B cells were more prevalent and exhibited a comparatively antiinflammatory profile in femoral plaque, whereas cytotoxic CD8+ T cells were more prevalent in carotid plaque. In conclusion, human femoral plaques exhibit distinct macrophage phenotypic and transcriptional profiles as well as diminished CD8+ T cell populations compared with human carotid plaques.

The Effect of PCSK9 Inhibition on the Stabilization of Atherosclerotic Plaque Determined by Biochemical and Diagnostic Imaging Methods

Atherosclerosis is a multifactorial, progressive, chronic inflammatory disease. Ultrasound and magnetic resonance imaging are the most accurate predictors of atherosclerotic plaque instability (MRI). Cytokines such as osteopontin, osteoprotegerin, and metalloproteinase 9 could be used as the most recent markers to identify and track the efficacy of anti-atherosclerotic therapy. Patients with USG and MRI-verified unstable atherosclerotic plaque were included in the study. Biomarker concentrations were measured and compared before and after PCSK9 inhibitor therapy. Additionally, concentrations prior to treatment were correlated with MRI images of the carotid artery. After treatment with alirocumab, the concentrations of MMP-9 (p < 0.01) and OPN, OPG (p < 0.05) decreased significantly. Furthermore, the results of OPN, OPG, and MMP 9 varied significantly depending on the type of atherosclerotic plaque in the MRI assay. In stable atherosclerotic plaques, the concentrations of OPN and OPG were greater (p < 0.01), whereas the concentration of MMP9 correlated with the instability of the plaque (p < 0.05). We demonstrated, probably for the first time, that alirocumab therapy significantly decreased the serum concentration of atherosclerotic plaque markers. In addition, we demonstrated the relationship between the type of atherosclerotic plaque as determined by carotid MRI and the concentration of these markers.

Spatial Transcriptional Mapping Reveals Site-Specific Pathways Underlying Human Atherosclerotic Plaque Rupture

BACKGROUND

Atherosclerotic plaque ruptures, triggered by blood flow-associated biomechanical forces, cause most myocardial infarctions and strokes.

OBJECTIVES

This study aims to investigate the exact location and underlying mechanisms of atherosclerotic plaque ruptures, identifying therapeutic targets against cardiovascular events.

METHODS

Histology, electron microscopy, bulk and spatial RNA sequencing on human carotid plaques were studied in proximal, most stenotic, and distal regions along the longitudinal blood flow direction. Genome-wide association studies were used to examine heritability enrichment and causal relationships of atherosclerosis and stroke. Associations between top differentially expressed genes (DEGs) and preoperative and postoperative cardiovascular events were examined in a validation cohort.

RESULTS

In human carotid atherosclerotic plaques, ruptures predominantly occurred in the proximal and most stenotic regions but not in the distal region. Histologic and electron microscopic examination showed that proximal and most stenotic regions exhibited features of plaque vulnerability and thrombosis. RNA sequencing identified DEGs distinguishing the proximal and most stenotic regions from the distal region which were deemed as most relevant to atherosclerosis-associated diseases as shown by heritability enrichment analyses. The identified pathways associated with the proximal rupture-prone regions were validated by spatial transcriptomics, firstly in human atherosclerosis. Of the 3 top DEGs, matrix metallopeptidase 9 emerged particularly because Mendelian randomization suggested that its high circulating levels were causally associated with atherosclerosis risk.

CONCLUSIONS

Our findings show plaque site-specific transcriptional signatures associated with proximal rupture-prone regions of carotid atherosclerotic plaques. This led to the geographical mapping of novel therapeutic targets, such as matrix metallopeptidase 9, against plaque rupture.

Role of plaque imaging for identification of vulnerable patients beyond the stage of myocardial ischemia

Chronic coronary syndrome (CCS) is a progressive disease, which often first manifests as acute coronary syndrome (ACS). Imaging modalities are clinically useful in making decisions about the management of patients with CCS. Accumulating evidence has demonstrated that myocardial ischemia is a surrogate marker for CCS management; however, its ability to predict cardiovascular death or nonfatal myocardial infarction is limited. Herein, we present a review that highlights the latest knowledge available on coronary syndromes and discuss the role and limitations of imaging modalities in the diagnosis and management of patients with coronary artery disease. This review covers the essential aspects of the role of imaging in assessing myocardial ischemia and coronary plaque burden and composition. Furthermore, recent clinical trials on lipid-lowering and anti-inflammatory therapies have been discussed. Additionally, it provides a comprehensive overview of intracoronary and noninvasive cardiovascular imaging modalities and an understanding of ACS and CCS, with a focus on histopathology and pathophysiology.

Metformin Directly Binds to MMP-9 to Improve Plaque Stability

Vulnerable atherosclerotic plaque rupture is the principal mechanism that accounts for myocardial infarction and stroke. High matrix metalloproteinase-9 (MMP-9) expression and activity have been proven to lead to plaque instability. Metformin, a first-line treatment for type 2 diabetes, is beneficial to plaque vulnerability. However, the mechanism underlying its anti-atherogenic effect remains unclear. Molecular docking and surface plasmon resonance experiments showed that metformin directly interacts with MMP-9, and incubated MMP-9 overexpressing HEK293A cells with metformin (1 μmol·L^-1) significantly attenuates MMP-9's activity using zymography and MMP activity assays. Moreover, metformin treatment drives MMP-9 degradation. Next, we constructed a carotid artery atherosclerotic plaque model and administered consecutive 14-day metformin (200 mg·kg^-1·d^-1) treatment by intragastric gavage. Immunofluorescence staining of the right carotid common artery and serum MMP activity assay results showed that metformin treatment decreased local plaque MMP-9 protein level and circulating MMP-9 activity, respectively. Histochemical staining revealed that after metformin treatment, the collagen content in plaque was significantly preserved, and the plaque vulnerability index decreased. These findings suggested that metformin improved atherosclerotic plaque stability by directly binding to MMP-9 and driving its degradation.

Circulating long non-coding RNA Coromarker expression correlated with inflammation, coronary artery stenosis, and plaque vulnerability in patients with coronary artery disease

BACKGROUND

The aim of the study was to assess the correlation between circulating long non-coding RNA (lncRNA) OTTHUMT00000387022 (named Coromarker) expression and disease severity, inflammatory cytokine levels, and plaque vulnerability in patients with coronary artery disease (CAD).

METHODS

A total of 134 participants who received coronary angiography were enrolled and classified them as CAD patients (N = 89) and controls (N = 45). Blood samples were obtained from all subjects. Quantitative polymerase chain reaction was used to evaluate Coromarker expression. The enzyme-linked immunosorbent test was used to measure inflammatory cytokines including high sensitivity C reactive protein (hsCRP), interleukin (IL)-1β (IL-1β), IL-6, NOD-like receptor protein 3 (NLRP3), and markers of coronary plaque stability including matrix metallopeptidase 9 (MMP-9) and soluble CD40 ligand (sCD40L). The severity of coronary stenosis was determined from the Gensini Score.

RESULTS

LncRNA Coromarker expression was elevated to a greater extent in CAD patients than in control subjects before and after adjustments for age/gender (both p < 0.001); it was an independent predictor of CAD risk (area under curve: 0.824, 95% CI: 0.732-0.915). Additionally, Coromarker expression was significantly associated with Gensini Score (r = 0.574, p < 0.001), hsCRP (r = 0.221, p = 0.015), IL-1β (r = 0.351, p < 0.001), IL-6 (r = 0.286, p < 0.01), and NLRP3 levels (r = 0.312, p < 0.001). Coromarker expression was found to be linked with MMP-9 (r = 0.260, p < 0.01) and sCD40L (r = 0.441, p < 0.001).

CONCLUSION

Circulating lncRNA Coromarker expression correlates with increased disease severity and inflammation as well as plaque vulnerability in patients with CAD.

TIMP-1 expression in coronary thrombi associate with myocardial injury in ST-elevation myocardial infarction patients

BACKGROUND

Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) are considered important both in atherosclerosis and remodeling after acute myocardial infarction (AMI). We aimed to study genetic expression and presence of MMP-2, MMP-9, TIMP-1, TIMP-2 and the extracellular MMP-inducer (EMMPRIN) in coronary thrombi. Circulating levels and genetic expression in circulating leukocytes were also assessed, and relations to degree of myocardial injury measured by troponin T and time from symptom to PCI were explored. Expression of cell markers were also analyzed, indicating relations to cell types.

METHODS

Intracoronary thrombi were aspirated from 33 patients with ST-elevation myocardial infarction (STEMI). Blood samples with Pax-gene tubes were drawn at end of PCI and the next day. RNA was isolated from thrombi and leukocytes, and genes were relatively quantified by RT-PCR. Each thrombus was preserved for histology and immunohistochemistry analyzes.

RESULTS

Genes coding for the five markers were present in 84-100% of thrombi and immunohistochemically stained in 96-100%. Expression of TIMP-1 in thrombi and in leukocytes correlated significantly to peak troponin T ( r = 0.393 P = 0.026, r = 0.469 P = 0.006, respectively). No significant correlations between genes expressed in thrombi and time from symptom to PCI were observed. TIMP-1 was connected mainly to monocytes/macrophages in the thrombi.

CONCLUSION

MMP-2, MMP-9, TIMP-1, TIMP-2 and EMMPRIN were highly expressed in human coronary thrombi. The correlation between troponin T and the expression of TIMP-1 both in thrombi and in leukocytes at time of PCI indicates that TIMP-1 plays a role in myocardial damage early post-MI.

Impact of MMP-9 Genetic Polymorphism and Concentration on the Development of Coronary Artery Disease in Ukrainian Population

Coronary artery disease (CAD) is one of the leading causes of death in Europe. It is known that atherosclerosis is the primary risk factor of CAD development. MMP-9 is involved in all stages of atherosclerosis and thus may contribute to CAD emergence. To investigate the influence of MMP-9 on the (CAD) development 25 patients with intact coronary arteries (CA), 40 patients with acute coronary syndrome (ACS), and 63 patients with chronic coronary syndrome (CCS) were enrolled in the study. Real-time PCR was carried out for genotyping on the rs17567-polymorphic locus, and ELISA study was performed to measure the MMP-9 plasma concentration. It was found the lower risk of MI occurrence for AG-carriers ( $P_a=0.023$ ; ORa = 0.299, 95% CI = 0.106–0.848) in Ukrainian population.

Neutrophil extracellular traps modulate inflammatory markers and uptake of oxidized LDL by human and murine macrophages

Neutrophil extracellular traps (NETs) are web-like structures, which are released upon neutrophil activation. It has previously been demonstrated that NETs are present in atherosclerotic lesions of both humans and animal models thus playing a decisive role in atherosclerosis. Besides, macrophages have a crucial role in disease progression, whereby classically activated M1 macrophages sustain inflammation and alternatively activated M2 macrophages display anti-inflammatory effects. Although NETs and macrophages were found to colocalize in atherosclerotic lesions, the impact of NETs on macrophage function is not fully understood. In the present study, we aimed to investigate the effect of NETs on human and murine macrophages in respect to the expression of pro-inflammatory cytokines, matrix metalloproteinases (MMPs) and uptake of oxidized LDL (oxLDL) in vitro. Human THP-1 and murine bone marrow-derived macrophages were cultured under M1 (LPS + IFN-γ)- and M2a (IL-4)-polarizing culture conditions and treated with NETs. To mimic intraplaque regions, cells were additionally cultured under hypoxic conditions. NETs significantly increased the expression of IL-1β, TNF-α and IL-6 in THP-M1 macrophages under normoxia but suppressed their expression in murine M1 macrophages under hypoxic conditions. Notably, NETs increased the number of oxLDL-positive M1 and M2 human and murine macrophages under normoxia, but did not influence formation of murine foam cells under hypoxia. However, oxLDL uptake did not strongly correlate with the expression of the LDL receptor CD36. Besides, upregulated MMP-9 expression and secretion by macrophages was detected in the presence of NETs. Again, hypoxic culture conditions dampened NETs effects. These results suggest that NETs may favor foam cell formation and plaque vulnerability, but exert opposite effects in respect to the inflammatory response of human and murine M1 macrophages. Moreover, effects of NETs on macrophages’ phenotype are altered under hypoxia.

Circulating Biomarkers Reflecting Destabilization Mechanisms of Coronary Artery Plaques: Are We Looking for the Impossible?

Despite significant strides to mitigate the complications of acute coronary syndrome (ACS), this clinical entity still represents a major global health burden. It has so far been well-established that most of the plaques leading to ACS are not a result of gradual narrowing of the vessel lumen, but rather a result of sudden disruption of vulnerable atherosclerotic plaques. As most of the developed imaging modalities for vulnerable plaque detection are invasive, multiple biomarkers were proposed to identify their presence. Owing to the pivotal role of lipids and inflammation in the pathophysiology of atherosclerosis, most of the biomarkers originated from one of those processes, whereas recent advancements in molecular sciences shed light on the use of microRNAs. Yet, at present there are no clinically implemented biomarkers or any other method for that matter that could non-invasively, yet reliably, diagnose the vulnerable plaque. Hence, in this review we summarized the available knowledge regarding the pathophysiology of plaque instability, the current evidence on potential biomarkers associated with plaque destabilization and finally, we discussed if search for biomarkers could one day bring us to non-invasive, cost-effective, yet valid way of diagnosing the vulnerable, rupture-prone coronary artery plaques.

The Role of Matrix Metalloproteinases in the Progression and Vulnerabilization of Coronary Atherosclerotic Plaques

Extracellular matrix (ECM) plays an important role in the development and progression of atherosclerotic lesions. Changes in the ECM are involved in the pathophysiology of many cardiovascular diseases, including atherosclerosis. Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteases, also known as matrixins, with proteolytic activity in the ECM, being responsible for the process of tissue remodeling in various systemic pathologies, including cardiac and vascular diseases. MMPs play an important role in maintaining normal vascular structure, but also in secondary cardiovascular remodeling, in the formation of atherosclerotic plaques and in their vulnerabilization process. In addition to the assigned effect of MMPs in vulnerable plaques, they have a well-defined role in post-infarction ventricular remodeling and in various types of cardiomyopathies, followed by onset of congestive heart failure, with repeated hospitalizations and death. The aim of this manuscript was to provide a summary on the role of serum matrix metalloproteinases in the process of initiation, progression and complication of atherosclerotic lesions, from a molecular level to clinical applicability and risk prediction in patients with vulnerable coronary plaques.

Increased Circulating Cathepsin L in Patients with Coronary Artery Disease

Cathepsin L (CatL) is a potent collagenase involved in atherosclerotic vascular remodeling and dysfunction in animals and humans. This study investigated the hypothesis that plasma CatL is associated with the prevalence of coronary artery disease (CAD). Between February May 2011 and January 2013, 206 consecutive subjects were enrolled from among patients who underwent coronary angiography and percutaneous coronary intervention treatment. Age-matched subjects (n = 215) served as controls. Plasma CatL and high-sensitive C-reactive protein (hs-CRP) and high-density lipoprotein cholesterol were measured. The patients with CAD had significantly higher plasma CatL levels compared to the controls (1.4 ± 0.4 versus 0.4 ± 0.2 ng/mL, P < 0.001), and the patients with acute coronary syndrome had significantly higher plasma CatL levels compared to those with stable angina pectoris (1.7 ± 0.7 versus 0.8 ± 0.4 ng/mL, P < 0.01). Linear regression analysis showed that overall, the plasma CatL levels were inversely correlated with the high-density lipoprotein levels (r = -0.32, P < 0.01) and positively with hs-CRP levels (r = 0.35, P < 0.01). Multiple logistic regression analyses shows that cathepsin L levels were independent predictors of CAD (add ratio, 1.8; 95% CI, 1.2 to 2.1; P < 0.01). These data demonstrated that increased levels of plasma CatL are closely associated with the presence of CAD and that circulating CatL serves as a useful biomarker for CAD.

The Role of Matrix Metalloproteinase-9 in Atherosclerotic Plaque Instability

Matrix metalloproteinase-9 (MMP-9) belongs to the MMP family and has been widely investigated. Excessive MMP-9 expression can enhance extracellular matrix degradation and promote plaque instability. Studies have demonstrated that MMP-9 levels are higher in vulnerable plaques than in stable plaques. Additionally, several human studies have demonstrated that MMP-9 may be a predictor of atherosclerotic plaque instability and a risk factor for future adverse cardiovascular and cerebrovascular events. MMP-9 deficiency or blocking MMP-9 expression can inhibit plaque inflammation and prevent atherosclerotic plaque instability. All of these results suggest that MMP-9 may be a useful predictive biomarker for vulnerable atherosclerotic plaques, as well as a therapeutic target for preventing atherosclerotic plaque instability. In this review, we describe the structure, function, and regulation of MMP-9. We also discuss the role of MMP-9 in predicting and preventing atherosclerotic plaque instability.

PR3 levels are impaired in plasma and PBMCs from Arabs with cardiovascular diseases

Cardiovascular disease (CVD) risks persist in patients despite treatment. CVD susceptibility also varies with sex and ethnicity and is not entirely explained by conventional CVD risk factors. The aim of the present study was to identify novel CVD candidate markers in circulating Peripheral blood mononuclear cells (PBMCs) and plasma from Arab obese subjects with and without CVD using proteomic approaches. Human adults with confirmed CVD (n = 208) and matched non-CVD controls (n = 152) living in Kuwait were examined in the present cross-sectional study. Anthropometric and classical biochemical parameters were determined. We employed a shotgun proteomic profiling approach on PBMCs isolated from a subset of the groups (n = 4, each), and differentially expressed proteins selected between the two groups were validated at the mRNA level using RT-PCR (n = 6, each). Plasma levels of selected proteins from the proteomics profiling: Proteinase-3 (PR3), Annexin-A3 (ANX3), Defensin (DEFA1), and Matrix Metalloproteinase-9 (MMP9), were measured in the entire cohort using human enzyme-linked immunosorbent assay kits and were subsequently correlated with various clinical parameters. Out of the 1407 we identified and quantified from the proteomics profiling, 47 proteins were dysregulated with at least twofold change between the two subject groups. Among the differentially expressed proteins, 11 were confirmed at the mRNA levels. CVD influenced the levels of the shortlisted proteins (MMP9, PR3, ANX3, and DEFA1) in the PBMCs and plasma differentially. Despite the decreased levels of both protein and mRNA in PBMCs, PR3 circulating levels increased significantly in patients with CVD and were influenced by neither diabetes nor statin treatment. No significant changes were; however, observed in the DEFA1, MMP9, and ANX3 levels in plasma. Multivariate logistic regression analysis revealed that only PR3 was independently associated with CVD. Our results suggest that the dysregulation of PR3 levels in plasma and PBMCs reflects underlying residual CVD risks even in the treated population. More prospective and larger studies are required to establish the role of PR3 in CVD progression.

YKL-40 promotes the progress of atherosclerosis independent of lipid metabolism in apolipoprotein E-/- mice fed a high-fat diet

YKL-40 is recently regarded as a pro-inflammatory cytokine involved in the pathological process of atherosclerosis and lipid metabolism. However, whether YKL-40 can directly influence the development of atherosclerosis and levels of lipid parameters is unknown. The aim of this study is to explore the effects of YKL-40 on atherosclerotic features, the levels of serum lipids, and biomarkers in apolipoprotein (E)-deficient (ApoE^-/-) mice fed a high-fat diet. ApoE^-/- mice were injected with a recombinant adenovirus expressing mouse YKL-40 or control adenovirus through the caudal vein. The levels of serum YKL-40, interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha), matrix metalloproteinase-9 (MMP-9), and soluble vascular cell-adhesion molecule 1 (sVCAM-1) were measured by ELISA. Lipid metabolism parameters were measured using immunoturbidimetric assay. The size of plaque area in aorta was evaluated by Oil Red O and hematoxylin/eosin (HE) staining. The content of collagen fibers was stained with Masson, and the content of macrophages and smooth muscle cells (SMCs) in atherosclerotic lesions was investigated by immunohistochemistry. The serum levels of total cholesterol and triglycerides were similar between these two groups. Compared with the control, the levels of serum YKL-40, IL-6, TNF-alpha, MMP-9, plaque size, and macrophages in plaques were significantly increased in mice with adenovirus overexpressing YKL-40. However, the content of collagen fibers and SMCs was remarkably decreased in mice with adenovirus overexpressing YKL-40 than that in control. YKL-40 prompts the progress of atherosclerosis maybe involved with its role of pro-inflammation, but does not affect lipid metabolism in ApoE^-/- mice fed a high-fat diet.

Biomarkers of Endothelial Dysfunction in Women With Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of childbearing age. The criteria required for the diagnosis identify various phenotypes, with different reproductive, metabolic, and cardiovascular (CV) risk characteristics. Emerging evidence links adipocyte-secreted hormones as candidates in the pathogenesis of endothelial dysfunction in PCOS, independently of additional risk factors. The aim of this review was to collect, analyze, and qualitatively resynthesize evidence on biomarkers of endothelial dysfunction (visfatin, vascular endothelial growth factor [VEGF], matrix metalloproteinase 9 [MMP-9]) in women with PCOS. Women with PCOS exhibit (a) increased plasma visfatin concentrations compared with controls with a similar body mass index; (b) increased VEGF production along with chronic, mild inflammation; and (c) increased MMP-9 concentrations, which might be related to either excessive CV risk or abnormalities of ovarian extracellular matrix remodeling, multiple cyst formation, follicular atresia, and chronic anovulation. As PCOS has been associated with CV risk, early identification of endothelial dysfunction is clinically relevant.

Study of Serum CD147 Level in Patients with Transient Ischemic Attack and CD147 Expression in Atherosclerotic Plaque

There is growing evidence that highlighted the potential effects of CD147 in atherosclerosis, but the potential implication of CD147 in diagnosis and treatment of transient ischemic attack (TIA) and acute cerebral infarction (ACI) is still unclear. In this work, we investigated the serum level of CD147 in patients with TIA and ACI, and CD147 expression in atherosclerotic plaque. The result showed significantly increasing serum level of CD147 in patients with TIA and ACI, and increasing amount of CD147 in vulnerable plaque compared with that in migrating plaque. The serum level of CD147 was correlation with risk of stroke after an episode of TIA. These results together suggest a potential involvement of CD147 in the development and progression of TIA and ACI and CD147 as a potential biomarker for stroke prediction.

Serum MMP-9 Diagnostics, Prognostics, and Activation in Acute Coronary Syndrome and Its Recurrence

Matrix metalloproteinase (MMP)-9 is crucial in atherosclerotic plaque rupture and tissue remodeling after a cardiac event. The balance between MMP-9 and endogenous inhibitor, tissue inhibitors of matrix metalloproteinase 1 (TIMP-1), is important in acute coronary syndrome (ACS). This is an age- and gender-matched case-control study of ACS (N = 669). Patients (45.7%) were resampled after recovery, and all were followed up for 6 years. The molecular forms of MMP-9 were investigated by gelatin zymography. Diagnostically, MMP-9 and the MMP-9/TIMP-1 molar ratio were associated with ACS (OR 5.81, 95% CI 2.65–12.76, and 4.96, 2.37–10.38). The MMP-9 concentrations decreased 49% during recovery (p < 0.001). The largest decrease of these biomarkers between acute and recovery phase (ΔMMP-9) protected the patients from major adverse cardiac events, especially the non-fatal events. The fatal events were associated with in vitro activatable MMP-9 levels (p = 0.028). Serum MMP-9 and the MMP-9/TIMP-1 molar ratio may be valuable in ACS diagnosis and prognosis. High serum MMP-9 activation potential is associated with poor cardiovascular outcome.

Usefulness of plasma matrix metalloproteinase-9 levels in prediction of in-hospital mortality in patients who received emergent percutaneous coronary artery intervention following myocardial infarction

The aim of the present study was to investigate the predictive value of the plasma matrix metalloproteinase-9 (MMP-9) level at admission for in-hospital mortality in patients who received emergency percutaneous coronary intervention (PCI) following AMI. A single blood sample was collected at admission from 155 consecutive AMI patients who underwent emergent PCI. The plasma levels of MMP-9 value (528.9±191.6 ng/ml) were significantly higher in the patients who died (n=24) than in the survivors (385.4±236.0 ng/ml) during 14 days of hospitalization (P=0.005). The age, left ventricle wall motion score index (WMIS), Global Registry of Acute Coronary Events (GRACE) score and B-type natriuretic peptide (BNP) levels and GENSINI score at admission were significantly different between the patients who died and those who survived (P<0.001, P=0.004, P<0.001 and P<0.001, respectively). Cut-off concentrations for prediction of death was identified from receiver operator characteristic (ROC) curves. Using the cut-off value (MMP-9 level 398.2 ng/ml) to stratify the patients into two groups, the group with higher MMP-9 levels had a greater rate of in-hospital mortality than the lower level group (P<0.001). With the exception of the GRACE score, among all biomarkers measured, in stepwise multiple logistic regressions, only the MMP-9 level predicted the risk of in-hospital death after adjustment for all other risk factors (odds ratio 5.02, 95% CI 1.44 to 17.55). In conclusion, a higher MMP-9 level is an independent predictor of in-hospital death in AMI patients who received emergency PCI.

Serum visfatin, vascular endothelial growth factor and matrix metalloproteinase-9 in women with polycystic ovary syndrome

AIM

To evaluate serum concentrations of visfatin, vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) in women with polycystic ovary syndrome (PCOS) and to investigate their possible role as early endothelial markers in PCOS.

METHODS

Forty-two women with PCOS and 42 controls, matched for age and weight, were included in the study. Serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, total testosterone (tT), Δ₄-androstenedione (Δ₄A), dehydroepinadrosterone sulphate (DHEA-S), 17-OH-progesterone, sex hormone-binding protein (SHBG), thyroid-stimulating hormone (TSH), free thyroxine (fT₄), visfatin, VEGF and MMP-9 were measured in all women; free androgen index (FAI) was calculated as well. Receiver-operating characteristic (ROC) analysis was performed to examine if visfatin, tT or FAI can predict the clinical status (PCOS or control).

RESULTS

LH, Δ₄A, tT and FAI concentrations were higher in PCOS than in controls (p = 0.002, 0.029, 0.0005 and 0.014, respectively). Visfatin, VEGF and MMP-9 concentrations were higher in women with PCOS than controls (p = 0.019, 0.001 and 0.002, respectively). In ROC analysis, area under the curve (AUC) in the prediction of clinical status was 0.641 for visfatin (p = 0.026), 0.731 for tT (p = 0.001) and 0.666 for FAI (p = 0.010), with no difference among them (p = 0.117).

CONCLUSIONS

Visfatin may induce the expression of pro-angiogenic factors, such as VEGF and MMP-9, in women with PCOS, inplying gradually development of endothelial dysfunction. Further studies are required to clarify these findings.

Plasma levels of matrix metalloproteinase 9 in patients undergoing off-pump coronary artery bypass grafting

BACKGROUND

Matrix metalloproteinase 9 (MMP9) has recently emerged as a risk predictor in patients with cardiovascular diseases. However, little is known about the significance of increased plasma MMP9 in patients with perioperative myocardial injury. We aimed to investigate the role of MMP9 in the occurrence of myocardial injury during off-pump coronary artery bypass grafting (OPCAB).

METHODS

A total of 34 consecutive patients with coronary artery diseases (CAD) were recruited in this prospective, observational study. All patients were operated for OPCAB surgery. Serial blood samples were collected preoperatively and 12 hours after surgery. MMP9, together with cardiac troponin I (cTnI), creatinine kinase myocardial b fraction (CK-MB), C-reactive protein (CRP), and N-terminal pro B-type natriuretic peptide (NT-proBNP) levels in plasma were measured at each time-point.

RESULTS

MMP9 levels increased significantly at 12 hours after surgery, attaining nearly 2 times the baseline levels (P=0.0001). There was a significant correlation between preoperative (pre-OP) circulating levels of MMP9 and the left ventricular ejection fraction (LVEF) (r=0.48; P=0.004) as well as European System for Cardiac Operative Risk Evaluation (EuroSCORE) II (r=0.43; P=0.012). Patients were in New York Heart Association (NYHA) functional class III or IV heart failure showed a significantly higher MMP9 levels (1,348.0±337.2 vs. 630.4±93.0 ng/L, P=0.012) as compared to the patients in NYHA functional class I and II. No significant correlation was observed between MMP9 and age (P=0.612), serum creatinine (P=0.185), CRP (P=0.207), NT-proBNP (P=0.058). A significant correlation was observed in these data between the post-OP MMP9 and cTnI (r=0.35; P=0.003).

CONCLUSIONS

Our study first established a connection between MMP9 and OPCAB procedure, suggesting that MMP9 could be a novel biomarker for identifying perioperative myocardial injury in patients undergoing OPCAB.

Matrix Metalloproteinase-9 as a Marker for Plaque Rupture and a Predictor of Adverse Clinical Outcome in Patients with Acute Coronary Syndrome: An Optical Coherence Tomography Study

OBJECTIVES

The present study sought to clarify the relationship between matrix metalloproteinase-9 (MMP-9) levels and plaque morphology demonstrated by optical coherence tomography (OCT), and to examine their prognostic impacts in patients with acute coronary syndrome (ACS).

METHODS

MMP-9 levels were measured for patients with ACS (n = 249). Among 249 patients, 120 with evaluable OCT images were categorized into patients with ruptured plaques (n = 65) and those with nonruptured plaques (n = 55) on the basis of culprit lesion plaque morphology demonstrated by OCT.

RESULTS

MMP-9 levels on admission were significantly higher in the rupture group than in the nonrupture group (p = 0.029). Although creatine kinase-MB (CK-MB) on admission was comparable between the groups, peak CK-MB was higher in the rupture group than in the nonrupture group (p < 0.001). By receiver operating characteristic curve analysis, the optimal cut-off value of MMP-9 to detect ruptured plaques was 65.5 ng/ml (p = 0.029). There was a nonstatistically significant trend toward increased cardiac death at 2 years (5.9 vs. 1.0%, p = 0.059) in patients with high MMP-9 (≥65.5 ng/ml) compared to those with low MMP-9 (<65.5 ng/ml).

CONCLUSIONS

MMP-9 can differentiate ACS with ruptured plaques from nonruptured plaques, and MMP-9 may be a valuable predictor of long-term cardiac mortality in patients with ACS reflecting plaque rupture.

Matrix Metalloproteinases and Subclinical Atherosclerosis in Chronic Kidney Disease: A Systematic Review

Background. Cardiovascular disease (CVD) remains a significant problem in Chronic Kidney Disease (CKD). Subclinical atherosclerosis identified by noninvasive methods could improve CVD risk prediction in CKD but these methods are often unavailable. We therefore systematically reviewed whether circulating levels of Matrix Metalloproteinases (MMPs) and tissue inhibitors (TIMPs) are associated with subclinical atherosclerosis in CKD, as this would support their use as biomarkers or pharmacologic targets. Methods. All major electronic databases were systematically searched from inception until May 2015 using appropriate terms. Studies involving CKD patients with data on circulating MMPs levels and atherosclerosis were considered and subjected to quality assessment. Results. Overall, 16 studies were identified for qualitative synthesis and 9 studies were included in quantitative synthesis. MMP-2 and TIMP-1 were most frequently studied while most studies assessed carotid Intima-Media Thickness (cIMT) as a measure of subclinical atherosclerosis. Only MMP-2 demonstrated a consistent positive association with cIMT. Considerable variability in cIMT measurement methodology and poor plaque assessment was found. Conclusions. Although MMPs demonstrate great potential as biomarkers of subclinical atherosclerosis, they are understudied in CKD and not enough data existed for meta-analysis. Larger studies involving several MMPs, with more homogenized approaches in determining the atherosclerotic burden in CKD, are needed.

Interleukin 18 and extracellular matrix metalloproteinase inducer cross-regulation: implications in acute myocardial infarction

Circulating interleukin-18 (IL-18) is thought to promote atherosclerosis and cardiovascular complications such as plaque rupture. Atherosclerosis is also characterized by smooth muscle cell migration, a consequence of extracellular matrix (ECM) degradation regulated by metalloproteinases (MMPs). Because extracellular matrix metalloproteinase inducer (EMMPRIN) has been shown to promote plaque instability by inducing ECM degradation and MMP synthesis, we investigated whether a cross-regulatory interaction exists between IL-18 and EMMPRIN in human monocytes. EMMPRIN levels in monocytes were markedly greater in 20 patients with acute myocardial infarction (AMI) compared with 20 patients with stable angina pectoris or 20 healthy volunteers (control group). The levels of IL-18 and MMP-9 in serum were also significantly greater in the AMI group in comparison with the other 2 groups. IL-18 levels positively correlated with increased levels of EMMPRIN in monocytes. In vitro, the expression of EMMPRIN was increased in monocytes cultured with IL-18, and IL-18 secretion was augmented in monocytes cultured with EMMPRIN. Gene silencing of EMMPRIN by small interfering RNA reduced monocyte secretion of both IL-18 and MMP-9. In the present study, cross-regulation between IL-18 and EMMPRIN in monocytes was demonstrated. This interaction may amplify the inflammatory cascade and be responsible for increased monocytic MMP-9 serum levels in atherosclerosis, contributing to atherosclerotic plaque destabilization and subsequent AMI.

Clinical Relevance of matrix metalloproteinase 9 in patients with acute coronary syndrome

We measured levels of matrix metalloproteinase 9 (MMP-9) as a potential risk factor in 75 patients with acute coronary syndrome (ACS) compared to 25 patients with stable angina (SA) and 20 healthy participants. Patients were studied stressing on smoking, hypertension, diabetes, lipid profile, cardiac enzymes, MMP-9, and electrocardiography. Patients with ACS had higher MMP-9 levels than the SA group. The highest MMP-9 levels were found among ST-elevated myocardial infarction (MI), while the lowest levels were found among the control group. The MMP-9 level was significantly higher among patients with ACS having poor disease outcome (recurrent ischemic attacks, congestive heart failure, or death). The MMP-9 cutoff value of 3100 pg/mL was able to discriminate MI from unstable angina (UA), while the best prognostic utility was established at 4700 pg/mL. We suggest that serum MMP-9 could be an early marker that discriminates MI from UA and predicts poor outcome in terms of disease severity and extent of disease complications.

Increased serum cathepsin K in patients with coronary artery disease

PURPOSE

Cathepsin K is a potent collagenase implicated in human and animal atherosclerosis-based vascular remodeling. This study examined the hypothesis that serum CatK is associated with the prevalence of coronary artery disease (CAD).

MATERIALS AND METHODS

Between January 2011 and December 2012, 256 consecutive subjects were enrolled from among patients who underwent coronary angiography and percutaneous coronary intervention treatment. A total of 129 age-matched subjects served as controls.

RESULTS

The subjects' serum cathepsin K and high sensitive C-reactive protein (hs-CRP) and high-density lipoprotein cholesterol were measured. The patients with CAD had significantly higher serum cathepsin K levels compared to the controls (130.8±25.5 ng/mL vs. 86.9±25.5 ng/mL, p<0.001), and the patients with acute coronary syndrome had significantly higher serum cathepsin K levels compared to those with stable angina pectoris (137.1±26.9 ng/mL vs. 102.6±12.9 ng/mL, p<0.001). A linear regression analysis showed that overall, the cathepsin K levels were inversely correlated with the high-density lipoprotein levels (r=-0.29, p<0.01) and positively with hs-CRP levels (r=0.32, p<0.01). Multiple logistic regression analyses shows that cathepsin K levels were independent predictors of CAD (odds ratio, 1.76; 95% confidence interval, 1.12 to 1.56; p<0.01).

CONCLUSION

These data indicated that elevated levels of cathepsin K are closely associated with the presence of CAD and that circulating cathepsin K serves a useful biomarker for CAD.

Environmental endocrine disruption of energy metabolism and cardiovascular risk

Rates of metabolic diseases have increased at an astounding rate in recent decades. Even though poor diet and physical inactivity are central drivers, these lifestyle changes alone fail to fully account for the magnitude and rapidity of the epidemic. Thus, attention has turned to identifying novel risk factors, including the contribution of environmental endocrine disrupting chemicals. Epidemiologic and preclinical data support a role for various contaminants in the pathogenesis of diabetes. In addition to the vascular risk associated with dysglycemia, emerging evidence implicates multiple pollutants in the pathogenesis of atherosclerosis and cardiovascular disease. Reviewed herein are studies linking endocrine disruptors to these key diseases that drive significant individual and societal morbidity and mortality. Identifying chemicals associated with metabolic and cardiovascular disease as well as their mechanisms of action is critical for developing novel treatment strategies and public policy to mitigate the impact of these diseases on human health.

Relationship between lysophosphatidic acid and matrix metalloproteinase-9 plasma concentrations and carotid atheromatous plaque stability in patients with cerebral infarction

Objective:

To investigate the correlation between plasma lysophosphatidic acid (LPA), matrix metalloproteinase (MMP)-9 and carotid atheromatous plaque stability in patients with cerebral infarction.

Method:

Patients with cerebral infarction underwent carotid artery duplex ultrasonography and transcranial Doppler monitoring for detection of microemboli. Patients were stratified by plaque type (no plaque, intima thickening, unstable plaque, stable plaque) and presence or absence of micoremboli. Plasma LPA and MMP-9 were quantified.

Result:

LPA and MMP-9 concentrations were significantly higher and microemboli positivity was significantly more common in patients with unstable plaque ( n = 21) than the other three groups (intima thickening, n = 16; stable plaque n = 41; no plaque; n = 12). There was a significant positive correlation between LPA and MMP-9 concentrations.

Conclusion:

Plasma LPA and MMP-9 concentrations may be useful biomarkers in the clinical identification and prediction of unstable plaque, and in guiding treatment.

Levels of cathepsins in acute myocardial infarction

AIMS/OBJECTIVE

Over expression of matrix degrading enzymes have been implicated in plaque destabilisation and rupture. Cathepsins associated with extracellular matrix breakdown make them intriguing suspects. The aim of the study was to analyse peripheral levels of cathepsin B and cathepsin K and their inhibitor cystatin C during acute myocardial infarction (AMI).

MATERIALS AND METHODS

Study population included AMI patients at acute event (AMI group, n=48), stable angina patients (stable angina group n = 17), and healthy individuals (Control group, n=31). Cathepsin B, cathepsin K, cystatin C, and matrix metalloproteinases (MMP)-9 were analysed by enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

Cathepsin B (45.9%) and cathepsin K (92.31%) at acute event of myocardial infarction (AMI group) increased (P=0.001) while cystatin C decreased marginally (12.5%) as compared to controls. Stable angina group, demonstrated only marginal reduction in all the parameters studied as compared to controls.

CONCLUSION

Cathepsin B and cathepsin K can be further evaluated as biomarkers in identifying high-risk individuals for AMI.

Circulating cathepsin K as a potential novel biomarker of coronary artery disease

BACKGROUND

Cathepsin K (CatK) is one of the most potent mammalian collagenases involved in atherosclerosis-based vascular disease. We investigated whether circulating CatK is associated with the prevalence of coronary artery disease (CAD).

METHODS

Two-hundred fifty-two consecutive subjects were enrolled from among patients who underwent coronary angiography and intravascular ultrasound analyses. One-hundred thirty-two age-matched subjects served as controls. Plasma CatK, intact procollagen type I N-terminal propeptide (I-PINP), and linked carboxy-terminal telopeptide of collagen type I (ICTP) were measured.

RESULTS

Patients with CAD had higher CatK levels (44.0 ± 31.2 versus 15.5 ± 8.3 ng/mL, P < 0.001) and ICTP/I-PINP ratios (0.2 ± 0.1 versus 0.04 ± 0.03, P < 0.001) than the controls. Patients with acute coronary syndrome had higher CatK levels than those with stable angina pectoris. Overall, linear regression analysis showed that the CatK levels correlated positively with ICTP/I-PINP ratios (r = 0.41, P < 0.001). Multiple logistic regression analysis showed that CatK levels were independent predictors of CAD (odds ratio, 1.15; 95% CI, 1.07 to 1.23; P < 0.01). Furthermore, CatK levels were also correlated positively with percent plaque volumes and inversely with percent fibrous volumes by intravascular ultrasound.

CONCLUSIONS

These data indicated that high levels of CatK are closely linked with the presence of CAD and that CatK serves as a novel biomarker for CAD.

C-reactive protein induces expression of matrix metalloproteinase-9: a possible link between inflammation and plaque rupture

BACKGROUND

Matrix metalloproteases (MMPs) have been implicated in the pathogenesis of acute coronary syndromes (ACS). However, little is known about the mechanisms responsible for MMP expression in ACS. C-reactive protein (CRP) not only is an independent risk factor for cardiovascular events, but also may exert direct pro-atherosclerotic effects. Therefore, we aimed at determining whether CRP might induce MMP-9 in two different experimental conditions: 1) smooth muscle cells (SMCs) in vitro, and 2) patients with ACS.

METHODS AND RESULTS

Effects of increasing concentrations of CRP on MMP-9 expression were evaluated in vitro in human SMCs. TIMP-1 protein expression, the selective inhibitor of MMP-9, was also evaluated. CRP dose-dependently induced MMP-9 expression in SMCs by promoting MMP-mRNA transcription, as well as MMP-9 secretion. In contrast, no differences were found for TIMP-1 protein expression. In vivo, MMP-9 and CRP levels were measured in blood samples obtained from the aorta (Ao) and the coronary sinus (Cs) of patients with normal coronary arteries (controls, n=21), stable angina (n=24), and ACS (n=30). Both MMP-9 and CRP plasma levels were significantly increased across the coronary circulation only in patients with ACS. Interestingly, a significant correlation between MMP-9 and CRP plasma levels was found.

CONCLUSIONS

CRP induced MMP-9 expression and activity in human SMCs in culture; patients presenting with ACS have increased transcoronary plasma levels of MMP-9 and CRP with a significant correlation between these two markers. This may explain the heightened risk of coronary events in subjects with elevated levels of CRP.

Association of circulating levels of MMP-8 with mortality from respiratory disease in patients with rheumatoid arthritis

Introduction

Matrix metalloproteinases (MMPs) are implicated in the destruction of the joint and have been shown to be strongly associated with inflammation in rheumatoid arthritis (RA). Circulating MMPs have also been associated with cardiovascular disease in the general population, and are predictive of cardiovascular mortality. The purpose of the present study was to determine whether circulating levels of MMPs are predictive of mortality in RA.

Methods

A multiplex suspension array system (Luminex^®) was used to measure levels of MMPs (1, 2, 3, 8 and 9) in sera taken at recruitment of RA patients (n = 487) in a study of factors associated with mortality in RA. Patients were tracked on the National Health Service Central Register for notification of death, and the relationship between baseline MMP levels and mortality was analysed using Cox proportional hazards regression analysis.

Results

At the time of follow-up, 204/486 patients had died, of which 94 (46.1%) had died of circulatory diseases, 49 of malignancy (24.0%), and 42 (20.6%) of respiratory diseases. In a stepwise analysis which included all MMPs, only MMP-8 was significantly associated with all cause mortality (P = 0.0007, 0.6% hazard ratio increase per ng/ml). No association was found between MMP levels and mortality due to circulatory disease or malignancy. However MMP-8 levels were strongly associated with mortality due to respiratory disease (P < 0.0001, 1.3% hazard ratio increase per ng/ml). The association with respiratory disease related mortality remained highly significant in multivariate models which included smoking as well as markers of severity and disease activity such as rheumatoid factor, nodular disease, and C-reactive protein (CRP).

Conclusions

The serum level of MMP-8 is a strong predictor of mortality in RA, especially that due to respiratory disease. This finding is consistent with increased activation of neutrophils in RA and identifies serum MMP-8 as a useful marker for increased risk of premature death.

Provitamin A carotenoids are independently associated with matrix metalloproteinase-9 in plasma samples from a general population

BACKGROUND AND AIM

Carotenoids in plasma are inversely associated with cardiovascular risk. Low levels can be explained by low dietary intake but also by a number of other factors including inflammatory activity. Given that matrix metalloproteinase (MMP)-9 has an important role in inflammation and cardiovascular disease, we hypothesized that circulating MMP-9 levels would be inversely related to total or single carotenoids in a general population cohort.

METHODS

A well-characterized population-based cohort of 285 Swedish men and women (45-69 years) was used for the present study. The intake of carotenoid-rich fruits and vegetables was estimated from a food frequency questionnaire. Levels of MMP-9, C-reactive protein (CRP), interleukin (IL)-6 and six major carotenoids [β-cryptoxanthine, α-carotene, β-carotene, lutein (+zeaxanthin) and lycopene] were determined in plasma.

RESULTS

Lower plasma levels of total and single carotenoids were associated with lower dietary intake of carotenoids, older age, male sex, lower physical activity, higher alcohol consumption, higher body mass index (BMI), higher systolic and diastolic blood pressures, lower levels of total cholesterol and HDL cholesterol and higher levels of CRP, IL-6 and MMP-9. After multivariate adjustments, plasma levels of total carotenoids and provitamin A carotenoids (β-cryptoxanthine, α-carotene and β-carotene) remained independently associated with sex, dietary intake of carotenoids, BMI, HDL cholesterol and MMP-9, whilst associations with CRP and IL-6 were not maintained. Neither dietary intake of carotenoid-rich fruits and vegetables, nor vitamin supplement use was associated with MMP-9, CRP or IL-6 levels.

CONCLUSION

Plasma carotenoids were associated with a variety of factors including age, sex, dietary intake and metabolic variables. A new finding was the independent relationship in plasma between low provitamin A carotenoids and high MMP-9, suggesting a link between these carotenoids, matrix turnover and arterial remodelling.

Salivary biomarkers associated with myocardial necrosis: results from an alcohol septal ablation model

OBJECTIVE

To determine if salivary biomarkers demonstrate utility for identifying aspects of myocardial necrosis.

METHODS

Twenty-one patients undergoing alcohol septal ablation (ASA) for treatment of hypertrophic cardiomyopathy provided serum and unstimulated whole saliva at baseline and incremental time points post-ASA. Samples were analyzed for seven biomarkers related to myocardial damage, inflammation, and tissue remodeling using immunosorbent assays. Levels were compared with baseline and levels observed in 97 healthy controls.

RESULTS

Biomarkers of myocardial damage and inflammation (ie, troponin I, creatine kinase-MB, myoglobin, C-reactive protein) rose in serum 2- to 812-fold after ASA (P < .01). Significant elevations of 2.0- to 3.5-fold were observed with C-reactive protein and troponin I in saliva (P < .02). Significant correlations between levels in serum and saliva were observed for C-reactive protein, matrix metalloproteinase-9, and myeloperoxidase (P < .001).

CONCLUSIONS

Select salivary biomarkers reflect changes that occur during, and subsequent to, myocardial necrosis caused by ASA.

Matrix metalloproteinases in vascular physiology and disease

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that primarily degrade components of the extracellular matrix (ECM). Remodeling of the ECM by MMPs is important in both physiological and pathological processes, including organ generation/regeneration, angiogenesis, wound healing, inflammation and tumor growth. In the vasculature, MMPs play a role in beneficial processes such as angiogenesis, collateral artery formation and thrombus resolution. However, MMP expression is also implicated in the pathogenesis of vascular diseases such as atherosclerosis, aortic aneurysms, plaque rupture and neointimal hyperplasia after balloon angioplasty. Here, we review the structure, functions and roles of MMPs in both neovascularization and vascular pathology and discuss the potential of, and challenges that face, adapting MMPs as therapeutic targets in vascular disease.

Prognosis by C-reactive protein and matrix metalloproteinase-9 levels in stable coronary heart disease during 15 years of follow-up

BACKGROUND AND AIM

Elevated CRP and matrix metalloproteinase-9 associate with increased risk of cardiovascular events, possibly because these plasma proteins mark vulnerable atherosclerotic plaques. We tested the hypothesis that levels of C-reactive protein (CRP) and matrix metalloproteinase-9 associate with prognosis in patients with stable coronary heart disease.

METHODS AND RESULTS

We measured baseline plasma CRP and matrix metalloproteinase-9 in 1090 patients with stable coronary heart disease and as the primary composite endpoint detected incident unstable angina, myocardial infarction and any death during 15 years of follow-up. CRP above versus below the median of 3.0 mg/L was associated with an increased cumulative incidence of unstable angina, myocardial infarction and any death combined (log-rank p < 0.0001). CRP above versus below the median had a corresponding hazard ratio of 1.5(95% CI, 1.3-1.8) after age adjustment, of 1.4(1.2-1.6) after multifactorial adjustment, and of 1.4(1.2-1.6) after multifactorial adjustment including degree of coronary disease. In contrast, matrix metalloproteinase-9 above versus below the median was not associated with risk of unstable angina, myocardial infarction and death.

CONCLUSIONS

Elevated CRP, but not elevated matrix metalloproteinase-9, associates with increased risk of unstable angina, myocardial infarction and death in patients with stable coronary heart disease.

Correlations between serum inflammation factors and left ventricular remodeling in acute ST segment elevation myocardial infarction

PURPOSE

To investigate the changes and correlations of the serum inflammation factors levels and left ventricular (LV) structure and function in patients with acute ST segment elevation myocardial infarction (STEMI).

MATERIALS AND METHODS

A prospective study was performed on 70 STEMI patients and 70 control subjects. Serum levels of interleukin-6 (IL-6), soluble CD40 ligand (sCD40L), metalloproteinase- 9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were measured by sandwich enzyme-linked immunosorbent assay (ELISA), and cardiac structure and function were assessed by echocardiography at admission and 3-year follow-up.

RESULTS

We found that the levels of serum IL-6, sCD40L and MMP-9 increased steadily among control subjects, remote myocardial infarction and acute STEMI patients, and the level of TIMP-1 elevated remarkly at 3-year follow-up visit in STEMI. The admission level of serum MMP-9 positively correlated with LV end-diastolic and end-diastole volume (r=0.294, p=0.022; r=0.269, p=0.036, respectively), and TIMP-1 positively correlated with E/A ratio (r=0.278, p=0.044) at 3-year follow-up.

CONCLUSION

The study indicates that admission levels of serum MMP-9 and TIMP-1 closely correlated with left ventricular structure and function, which may be involved in the process of post-infarction remodeling of myocardium.

Circulating levels of matrix metalloproteinase-9 and abdominal aortic pathology: from the Dallas Heart Study

Prior reports have associated increased circulating levels of matrix metalloproteinase-9 (MMP-9), an endopeptidase active in the extracellular matrix, with the formation and rupture of aortic aneurysms, raising the possibility that MMP-9 may be a useful diagnostic or therapeutic target for aortic pathology. However, associations between MMP-9 and pathological abdominal aortic phenotypes in the general population have not been reported. In the Dallas Heart Study, a population-based sample of Dallas County residents (n = 2304), we measured MMP-9 and performed magnetic resonance imaging (MRI) of the abdominal aorta, measuring aortic compliance, plaque, wall thickness and luminal diameter. After adjustment for traditional cardiac risk factors and body size, higher MMP-9 quartiles were independently associated with higher aortic wall thickness and larger luminal diameter (p < 0.0001 for each), but not abdominal aortic plaque (p = 0.08), coronary artery calcium (p = 0.20) or the aortic luminal diameter/aortic wall thickness ratio (p = 0.37), supporting the hypothesis that therapies targeting MMP-9 may affect the abdominal aortic wall and modify aortic pathology.

Matrix metalloproteinase-9 for the earliest stage acute coronary syndrome

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) is regarded as a biomarker of plaque rupture or vulnerability and is elevated in patients with acute coronary syndrome (ACS). The aim of the present study was to evaluate the diagnostic value of MMP-9 for early ACS (≤4h of onset) and late ACS (>4h after onset), compared with high-sensitivity troponin T (hs-TnT).

METHODS AND RESULTS

MMP-9 and hs-TnT were measured in 200 patients with ST elevation ACS (STEACS; 115 early STEACS and 85 late STEACS patients), and 66 patients with non-ST elevation ACS (NSTEACS; 25 early NSTEACS and 41 late NSTEACS patients). Forty patients with stable angina pectoris (SAP) were enrolled as a control group. MMP-9 levels were significantly higher in patients with early STEACS (P<0.001), early NSTEACS (P<0.001), late STEACS (P<0.001) and late NSTEACS (P=0.025) than SAP. MMP-9 levels were significantly higher in patients with early STEACS (P=0.017) and early NSTEACS (P=0.034) than late STEACS and late NSTEACS, respectively. Levels of hs-TnT were significantly lower in patients with early STEACS (P<0.001) and early NSTEACS (P=0.007) than late STEACS and late NSTEACS, respectively. On receiver operating characteristic curve analysis, area under the curve of early STEACS, early NSTEACS, late STEACS and late NSTEACS was 0.880, 0.782, 0.790 and 0.648 for MMP-9, and 0.707, 0.725, 0.993 and 0.920 for hs-TnT, respectively.

CONCLUSIONS

MMP-9 levels were elevated earlier than hs-TnT and had a higher diagnostic value for early ACS, but not for late ACS, reflecting plaque rupture or vulnerability.