Plasma levels of matrix metalloproteinases and their inhibitors in hypertension: a systematic review and meta-analysis

Metalloproteinases (MMPs) in hypertensive disorders: role, function, pharmacology, and potential strategies to mitigate pathophysiological changes

Matrix metalloproteinases (MMPs) are a family of enzymes that play an important role in the pathophysiology of hypertensive disorders, particularly through their involvement in extracellular matrix (ECM) remodeling and vascular dysfunction. Their activity is closely linked to hypertension-mediated organ damage, which affects the vascular and cardio-renal systems. MMPs are responsible for degrading various components of the ECM, which is crucial for maintaining vascular structure and function. In hypertensive patients, several MMPs, including MMP-1, MMP-3, and MMP-9, are often found at elevated levels. This is associated with vascular remodeling and dysfunction due to chronic high blood pressure. The activation of MMPs in hypertension can be triggered by several factors, such as oxidative stress, inflammatory cytokines, and vasoactive agents like angiotensin II. In addition to increasing MMP activity, these variables cause an imbalance between MMPs and tissue inhibitors of metalloproteinases (TIMPs), which are the MMPs' natural inhibitors. This imbalance contributes to excessive degradation of the ECM and promotes pathological changes in vascular smooth muscle cells (VSMCs), leading to their transition from a contractile to a synthetic phenotype. This shift facilitates cell growth and migration, exacerbating vascular remodeling. Given their critical roles in hypertension-related organ damage, MMPs are being explored as potential pharmacological targets. Inhibitors of MMPs may help mitigate the adverse effects of hypertension by restoring balance in ECM remodeling processes. Understanding their mechanisms opens avenues for targeted therapies that could significantly improve outcomes for individuals suffering from hypertension-related complications.

Identification of risk factors for postoperative persistent hypertension in patients with pheochromocytoma

BACKGROUND

Surgical resection is the primary management for pheochromocytoma. However, some patients with pheochromocytoma still suffer from hypertension after successful adrenalectomy. The risk factors for postoperative persistent hypertension remain unclear. Thus the aim of the present study was to identify the risk factors of postoperative persistent hypertension in patients with pheochromocytoma concomitant with hypertension.

METHODS

We retrospectively analyzed 259 patients with pheochromocytoma who underwent adrenalectomy in our hospital between January 1, 2007, and December 31, 2018. Patients' demographics, comorbidities, and perioperative data were recorded. The odds ratio (OR) and 95% confidence interval were measured through binary logistic regression. The cutoff values and the area under the curve (AUC) for continuous risk factors of persistent hypertension after adrenalectomy were calculated through receiver operating characteristic curve analysis.

RESULTS

Of the 259 patients, 40.9% (106/259) patients experienced postoperative persistent hypertension. Three independent risk factors of persistent hypertension in patients with pheochromocytoma after adrenalectomy were found to be older age (OR = 1.16, p = 0.037), longer duration of hypertension (OR = 3.10, p = 0.01), and concomitance with cardiovascular events (yes vs. no, OR = 17.17, p = 0.049). The cutoff value of age and duration of hypertension was 66 years (AUC = 0.741, p < 0.0001) and 27 months (AUC = 0.991, p < 0.0001), respectively.

CONCLUSIONS

Collectively, older age, a longer duration of hypertension, and concomitance with cardiovascular events were independent risk factors of persistent hypertension in patients with pheochromocytoma after adrenalectomy. These findings may help in improving perioperative management and follow-up strategies.

TIMP-1 in the prognosis of patients who underwent coronary artery bypass surgery: a 12-year follow-up study

Introduction

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) have been linked to clinical outcomes in patients with coronary artery disease (CAD). However, the prognostic value of TIMP-1 in patients with CAD who underwent coronary artery bypass grafting (CABG) has not been elucidated. We aimed to investigate the correlations of TIMP-1 with high-sensitivity C-reactive protein (hs-CRP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in the long-term prognosis of consecutive patients who underwent CABG.

Methods

A total of 234 patients (age: 70.4 ± 10.5 years, 84.6% men) with CAD who underwent CABG were prospectively enrolled. Preoperative levels of MMPs, TIMP-1, hs-CRP, and NT-proBNP were recorded. Major adverse cardiovascular events (MACE) were defined as non-fatal myocardial infarction, non-fatal stroke, and cardiovascular death.

Results

During a median follow-up of 12.1 years, 120 deaths were recorded. The deceased were older, had more manifest acute coronary syndrome (ACS), a lower left ventricular ejection fraction (LVEF), and an estimated glomerular filtration rate (eGFR), but significantly higher MMP13, TIMP-1, hs-CRP, and NT-proBNP compared with the survivors. After adjusting for age, sex, manifest ACS, eGFR, LVEF, total cholesterol, and triglycerides, TIMP-1 (hazard ratio and 95% confidence intervals per SD: 1.506, 1.183-1.917), hs-CRP (1.349, 1.183-1.561), and NT-ProBNP (1.707, 1.326-2.199) were all independently associated with all-cause mortality. The mediation analysis revealed that the mortality risks of TIMP-1 were partially mediated by NT-proBNP (62.2%) and hs-CRP (25.3%). The associations of TIMP-1 with MACE were partially mediated by NT-proBNP (54.4%) but not hs-CRP.

Conclusions

TIMP-1 was an independent predictor of long-term outcomes after CABG, with possible roles in subclinical inflammation and postoperative cardiac remodeling.

Elevated matrix metalloproteinase‑9 expression is associated with COVID‑19 severity: A meta‑analysis

The present meta-analysis investigated the clinical value of serum matrix metalloproteinase (MMP)-9 levels in Coronavirus Disease 2019 (COVID-19) patients. Studies assessing the outcomes of patients with COVID-19 in correlation with the MMP-9 levels were retrieved from PubMed, Web of Science, EMBASE, Cochrane, WANFANG, and CNKI. A meta-analysis was performed to compare the serum MMP-9 levels between different patient groups: Severe vs. non-severe; acute respiratory distress syndrome (ARDS) vs. non-ARDS; non-survivors vs. survivors; neurologic syndrome vs. non-neurologic syndrome; and obese diabetic vs. non-obese diabetic. A total of 2,062 COVID-19-confirmed patients from 12 studies were included in this meta-analysis. The serum MMP-9 levels were significantly higher in patients with severe COVID-19 than in those with non-severe COVID-19 [weighted mean difference (WMD) 246.61 (95% confidence interval (CI), 115.86-377.36), P<0.001]. Patients with ARDS exhibited significantly higher MMP-9 levels than those without ARDS [WMD 248.55 (95% CI, 63.84-433.25), P<0.001]. The MMP-9 levels in the non-survivors did not significantly differ from those in the survivors [WMD 37.79 (95% CI, -18.08-93.65), P=0.185]. Patients with comorbidities, including neurological syndromes, and obese diabetic patients had significantly higher MMP-9 levels than those without comorbidities [WMD 170.73 (95% CI, 95.61-245.85), P<0.001]. Serum MMP-9 levels were associated with COVID-19 severity and may serve as a therapeutic target for improving the prognosis of patients with COVID-19.

Multi-Omic Candidate Screening for Markers of Severe Clinical Courses of COVID-19

BACKGROUND

Severe coronavirus disease 2019 (COVID-19) disease courses are characterized by immuno-inflammatory, thrombotic, and parenchymal alterations. Prediction of individual COVID-19 disease courses to guide targeted prevention remains challenging. We hypothesized that a distinct serologic signature precedes surges of IL-6/D-dimers in severely affected COVID-19 patients.

METHODS

We performed longitudinal plasma profiling, including proteome, metabolome, and routine biochemistry, on seven seropositive, well-phenotyped patients with severe COVID-19 referred to the Intensive Care Unit at the German Heart Center. Patient characteristics were: 65 ± 8 years, 29% female, median CRP 285 ± 127 mg/dL, IL-6 367 ± 231 ng/L, D-dimers 7 ± 10 mg/L, and NT-proBNP 2616 ± 3465 ng/L.

RESULTS

Based on time-series analyses of patient sera, a prediction model employing feature selection and dimensionality reduction through least absolute shrinkage and selection operator (LASSO) revealed a number of candidate proteins preceding hyperinflammatory immune response (denoted ΔIL-6) and COVID-19 coagulopathy (denoted ΔD-dimers) by 24-48 h. These candidates are involved in biological pathways such as oxidative stress/inflammation (e.g., IL-1alpha, IL-13, MMP9, C-C motif chemokine 23), coagulation/thrombosis/immunoadhesion (e.g., P- and E-selectin), tissue repair (e.g., hepatocyte growth factor), and growth factor response/regulatory pathways (e.g., tyrosine-protein kinase receptor UFO and low-density lipoprotein receptor (LDLR)). The latter are host- or co-receptors that promote SARS-CoV-2 entry into cells in the absence of ACE2.

CONCLUSIONS

Our novel prediction model identified biological and regulatory candidate networks preceding hyperinflammation and coagulopathy, with the most promising group being the proteins that explain changes in D-dimers. These biomarkers need validation. If causal, our work may help predict disease courses and guide personalized treatment for COVID-19.

Potential molecular mechanism underlying cardiac fibrosis in diabetes mellitus: a narrative review

BACKGROUND

Diabetes mellitus (DM) is among the most common risk factors for cardiovascular disease in the world with prevalence of more than 500 million population in 2021. Cardiac fibrosis with its complex process has been hypothesized as one of the mechanisms explaining development of heart failure in diabetic patients. Recently, the biomolecular mechanism of cardiac fibrosis in the hyperglycemia setting has been focusing around transforming growth factor β-1 (TGFβ-1) as a major factor. However, there is interplay role of several factors including microRNAs (miRNAs) which acts as a potential regulator of cardiac fibrosis connected with TGFβ-1. In this review, we explored interplay role of several factors including microRNAs which acts as a potential regulator of cardiac fibrosis connected with TGFβ-1 in diabetes mellitus. This narrative review included articles from the PubMed and Science Direct databases published in the last 10 years (2012-2022).

MAIN TEXT

In diabetic patients, excessive activation of myofibroblasts occurs and triggers pro-collagen to convert into mature collagen to fill the cardiac interstitial space resulting in a pathological process of extracellular matrix remodeling. The balance between matrix metalloproteinase (MMP) and its inhibitor (tissue inhibitor of metalloproteinase, TIMP) is crucial in degradation of the extracellular matrix. Diabetes-related cardiac fibrosis is modulated by increasing level of TGF-β1 mediated by cellular components, including cardiomyocyte and non-cardiomyocyte cells involving fibroblasts, vascular pericytes smooth muscle cells, endothelial cells, mast cells, macrophages, and dendritic cells. Several miRNAs such as miR-21, miR-9, miR-29, miR-30d, miR-144, miR-34a, miR-150, miR-320, and miR-378 are upregulated in diabetic cardiomyopathy. TGF-β1, together with inflammatory cytokines, oxidative stress, combined sma and the mothers against decapentaplegic (smad) protein, mitogen-activated protein kinase (MAPK), and microRNAs, is interconnectedly involved in extracellular matrix production and fibrotic response. In this review, we explored interplay role of several factors including microRNAs which acts as a potential regulator of cardiac fibrosis connected with TGFβ-1 in diabetes mellitus.

CONCLUSIONS

Long-term hyperglycemia activates cardiac fibroblast via complex processes involving TGF-β1, miRNA, inflammatory chemokines, oxidative stress, smad, or MAPK pathways. There is increasing evidence of miRNA's roles lately in modulating cardiac fibrosis.

Matrix Metalloproteinases in Cardioembolic Stroke: From Background to Complications

Matrix metalloproteinases (MMPs) are endopeptidases participating in physiological processes of the brain, maintaining the blood-brain barrier integrity and playing a critical role in cerebral ischemia. In the acute phase of stroke activity, the expression of MMPs increase and is associated with adverse effects, but in the post-stroke phase, MMPs contribute to the process of healing by remodeling tissue lesions. The imbalance between MMPs and their inhibitors results in excessive fibrosis associated with the enhanced risk of atrial fibrillation (AF), which is the main cause of cardioembolic strokes. MMPs activity disturbances were observed in the development of hypertension, diabetes, heart failure and vascular disease enclosed in CHA₂DS₂VASc score, the scale commonly used to evaluate the risk of thromboembolic complications risk in AF patients. MMPs involved in hemorrhagic complications of stroke and activated by reperfusion therapy may also worsen the stroke outcome. In the present review, we briefly summarize the role of MMPs in the ischemic stroke with particular consideration of the cardioembolic stroke and its complications. Moreover, we discuss the genetic background, regulation pathways, clinical risk factors and impact of MMPs on the clinical outcome.

Pathophysiology of Cardiovascular Diseases: New Insights into Molecular Mechanisms of Atherosclerosis, Arterial Hypertension, and Coronary Artery Disease

Cardiovascular diseases (CVDs) are disorders associated with the heart and circulatory system. Atherosclerosis is its major underlying cause. CVDs are chronic and can remain hidden for a long time. Moreover, CVDs are the leading cause of global morbidity and mortality, thus creating a major public health concern. This review summarizes the available information on the pathophysiological implications of CVDs, focusing on coronary artery disease along with atherosclerosis as its major cause and arterial hypertension. We discuss the endothelium dysfunction, inflammatory factors, and oxidation associated with atherosclerosis. Mechanisms such as dysfunction of the endothelium and inflammation, which have been identified as critical pathways for development of coronary artery disease, have become easier to diagnose in recent years. Relatively recently, evidence has been found indicating that interactions of the molecular and cellular elements such as matrix metalloproteinases, elements of the immune system, and oxidative stress are involved in the pathophysiology of arterial hypertension. Many studies have revealed several important inflammatory and genetic risk factors associated with CVDs. However, further investigation is crucial to improve our knowledge of CVDs progression and, more importantly, accelerate basic research to improve our understanding of the mechanism of pathophysiology.

MMPs and TIMPs levels are correlated with anthropometric parameters, blood pressure, and endothelial function in obesity

The association between matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinases (TIMPs) and obesity as well as obesity-related disease including metabolic syndrome is not fully explored. Our aims are that: (i) to evaluate the plasma levels of MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1, TIMP-2 and their ratios in non-obese people, overweight and obese people with or without metabolic syndrome, (ii) to investigate correlations between MMPs or TIMPs levels and several anthropometric parameters, blood pressure, endothelial function. Anthropometric and biochemical parameters were determined in 479 randomly selected participants, subdividing according to body mass index (BMI) and metabolic syndrome status. Plasma MMPs and TIMPs levels were measured. The assessment of endothelial function was characterized in people with obesity, overweight and non-obese, using laser Doppler Flowmetry. Obese people have elevated MMP-1, MMP-2, TIMP-1, TIMP-2 levels and decreased MMP-3/TIMP-1 and MMP-9/TIMP-1 ratios compared with non-obese people. MMP-1 levels and MMP-1/TIMP-1 ratio were positively correlated with BMI and waist circumference (WC) while MMP-2 levels were negatively correlated with BMI and WC values in obese people. MMP-3 levels and MMP-3/TIMP-1 ratio were positively correlated with systolic blood pressure (SBP) or diastolic blood pressure (DBP) in obese and metabolic syndrome people. Additionally, MMP-9 levels and MMP-9/TIMP-1 ratio were negatively correlated with endothelium-dependent response in obese and metabolic syndrome people. MMP-1, MMP-2, TIMP-1, TIMP-2 levels were increased in obese subjects. Significant correlations between anthropometric parameters and MMP-1 as well as MMP-1/TIMP-1 ratio supported these results. MMP-3 and -9 levels as well as their ratios with TIMP-1 were associated with blood pressure and endothelial-dependent response, respectively. In conclusion, our results demonstrated that MMP-1, MMP-3 and MMP-9 levels were correlated with several obesity-related parameters including BMI, WC, blood pressure and endothelial-dependent response. Our findings will hopefully provide new aspects for the use of MMPs and TIMPs as clinical biomarkers in obesity-related cardiovascular diseases such as metabolic syndrome and hypertension. The lack of measure of MMPs activity in plasma and relevant organs/tissues in obesity and metabolic syndrome is considered as a limitation in this report.

MMP-2 and MMP-9 levels in plasma are altered and associated with mortality in COVID-19 patients

Respiratory symptoms are one of COVID-19 manifestations, and the metalloproteinases (MMPs) have essential roles in the lung physiology. We sought to characterize the plasmatic levels of matrix metalloproteinase-2 and 9 (MMP-2 and MMP-9) in patients with severe COVID-19 and to investigate an association between plasma MMP-2 and MMP-9 levels and clinical outcomes and mortality. MMP-2 and MMP-9 levels in plasma from patients with COVID-19 treated in the ICU (COVID-19 group) and Control patients were measured with the zymography. The study groups were matched for age, sex, hypertension, diabetes, BMI, and obesity profile. MMP-2 levels were lower and MMP-9 levels were higher in a COVID-19 group (p < 0.0001) compared to Controls. MMP-9 levels in COVID-19 patients were not affected by comorbidity such as hypertension or obesity. MMP-2 levels were affected by hypertension (p < 0.05), but unaffected by obesity status. Notably, hypertensive COVID-19 patients had higher MMP-2 levels compared to the non-hypertensive COVID-19 group, albeit still lower than Controls (p < 0.05). No association between MMP-2 and MMP-9 plasmatic levels and corticosteroid treatment or acute kidney injury was found in COVID-19 patients. The survival analysis showed that COVID-19 mortality was associated with increased MMP-2 and MMP-9 levels. Age, hypertension, BMI, and MMP-2 and MMP-9 were better predictors of mortality during hospitalization than SAPS3 and SOFA scores at hospital admission. In conclusion, a significant association between MMP-2 and MMP-9 levels and COVID-19 was found. Notably, MMP-2 and MMP-9 levels predicted the risk of in-hospital death suggesting possible pathophysiologic and prognostic roles.

Matrix metalloproteinase-9 as a messenger in the cross talk between obstructive sleep apnea and comorbid systemic hypertension, cardiac remodeling, and ischemic stroke: a literature review

STUDY OBJECTIVES

OSA is a common sleep disorder. There is a strong link between sleep-related breathing disorders and cardiovascular and cerebrovascular diseases. Matrix metalloproteinase-9 (MMP-9) is a biological marker for extracellular matrix degradation, which plays a significant role in systemic hypertension, myocardial infarction and postmyocardial infarction heart failure, and ischemic stroke. This article reviews MMP-9 as an inflammatory mediator and a potential messenger between OSA and OSA-induced comorbidities.

METHODS

We reviewed the MEDLINE database (PubMed) for publications on MMP-9, OSA, and cardiovascular disease, identifying 1,592 studies and including and reviewing 50 articles for this work.

RESULTS

There is strong evidence that MMP-9 and tissue inhibitor of metalloproteinase-1 levels are elevated in patients with OSA (mainly MMP-9), systemic hypertension, myocardial infarction, and postmyocardial infarction heart failure. Our study showed variable results that could be related to the sample size or to laboratory methodology.

CONCLUSIONS

MMP-9 and its endogenous inhibitor, tissue inhibitor of metalloproteinase-1, are a common denominator in OSA, systemic hypertension, myocardial infarction, and heart failure. This characterization makes MMP-9 a target for developing novel selective inhibitors that can serve as adjuvant therapy in patients with OSA, which may ameliorate the cardiovascular and cerebrovascular mortality associated with OSA.

The Roles of Matrix Metalloproteinases and Their Inhibitors in Human Diseases

Matrix metalloproteinases (MMPs) are a family of zinc-dependent extracellular matrix (ECM) remodeling endopeptidases that have the capacity to degrade almost every component of the ECM. The degradation of the ECM is of great importance, since it is related to embryonic development and angiogenesis. It is also involved in cell repair and the remodeling of tissues. When the expression of MMPs is altered, it can generate the abnormal degradation of the ECM. This is the initial cause of the development of chronic degenerative diseases and vascular complications generated by diabetes. In addition, this process has an association with neurodegeneration and cancer progression. Within the ECM, the tissue inhibitors of MMPs (TIMPs) inhibit the proteolytic activity of MMPs. TIMPs are important regulators of ECM turnover, tissue remodeling, and cellular behavior. Therefore, TIMPs (similar to MMPs) modulate angiogenesis, cell proliferation, and apoptosis. An interruption in the balance between MMPs and TIMPs has been implicated in the pathophysiology and progression of several diseases. This review focuses on the participation of both MMPs (e.g., MMP-2 and MMP-9) and TIMPs (e.g., TIMP-1 and TIMP-3) in physiological processes and on how their abnormal regulation is associated with human diseases. The inclusion of current strategies and mechanisms of MMP inhibition in the development of new therapies targeting MMPs was also considered.

Matrix Metalloproteinases and Hypertension-Mediated Organ Damage: Current Insights

Matrix metalloproteinases (MMPs) are important extracellular enzymes involved in many physiological and pathological processes. Changes in the activity and concentration of specific MMPs, as well as the unbalance with their inhibitors (tissue inhibitors of metalloproteinases – TIMPs), have been described as a part of the pathogenic cascade promoted by arterial hypertension. MMPs are able to degrade various protein substrates in the extracellular matrix, to influence endothelial cells function, vascular smooth muscle cells migration, proliferation and contraction, and to stimulate cardiomyocytes changes. All these processes can be activated by chronically elevated blood pressure values. Animal and human studies demonstrated the key function of MMPs in the pathogenesis of hypertension-mediated vascular, cardiac, and renal damage, besides age and blood pressure values. Thus, the role of MMPs as biomarkers of hypertension-mediated organ damage and potential pharmacological treatment targets to prevent further cardiovascular and renal complications in hypertensive population is increasingly supported. In this review, we aimed to describe the main scientific evidence about the behavior of MMPs in the development of vascular, cardiac, and renal damage in hypertensive patients.

Origins of Primary Hypertension in Children

Although relatively rare in childhood, primary hypertension (PH) is thought to have originated in childhood and may be even determined perinatally. PH prevalence increases in school-age children and affects 11% of 18-year-old adolescents. Associated with metabolic risk factors, elevated blood pressure in childhood is carried into adulthood. Analysis of the phenotype of hypertensive children has revealed that PH is a complex of anthropometric and neuro-immuno-metabolic abnormalities, typically found in hypertensive adults. Children with elevated blood pressure have shown signs of accelerated biological development, which are closely associated with further development of PH, metabolic syndrome, and cardiovascular disease in adulthood. At the time of diagnosis, hypertensive children were reported to have significant arterial remodelling expressed as significantly increased carotid intima-media thickness, increased stiffness of large arteries, lower area of microcirculation, and decreased endothelial function. These changes indicate that their biological age is 4 to 5 years older than their normotensive peers. All these abnormalities are typical features of early vascular aging described in adults with PH. However, as these early vascular changes in hypertensive children are closely associated with features of accelerated biological development and neuro-immuno-metabolic abnormalities observed in older subjects, it seems that PH in childhood is not only an early vascular aging event, but also an early biological maturation phenomenon.

Homotrimeric MMP-9 is an active hitchhiker on alpha-2-macroglobulin partially escaping protease inhibition and internalization through LRP-1

Proteolysis is a crucial process in life, tightly controlled by numerous natural protease inhibitors. In human blood, alpha-2-macroglobulin is an emergency protease inhibitor preventing coagulation and damage to endothelia and leukocytes. With the use of a unique protease trapping mechanism, alpha-2-macroglobulin lures active proteases into its snap-trap, shields these from potential substrates and 'flags' their complex for elimination by receptor-mediated endocytosis. Matrix metalloprotease-9/gelatinase B is a secreted protease increased in blood of patients with inflammations, vascular disorders and cancers. Matrix metalloprotease-9 occurs as monomers and stable homotrimers, but the reason for their co-existence remains obscure. We discovered that matrix metalloprotease-9 homotrimers undergo reduced anti-proteolytic regulation by alpha-2-macroglobulin and are able to travel as a proteolytically active hitchhiker on alpha-2-macroglobulin. As a comparison, we revealed that monomeric active matrix metalloprotease-9 is efficiently trapped by human plasma alpha-2-macroglobulin and this masks the detection of activated matrix metalloprotease-9 with standard analysis techniques. In addition, we show that alpha-2-macroglobulin/trimer complexes escape clearance through the receptor low-density lipoprotein receptor-related protein 1, also known as the alpha-2-macroglobulin receptor. Thus, the biochemistry and biology of matrix metalloprotease-9 monomers and trimers are completely different as multimerization enables active matrix metalloprotease-9 to partially avoid alpha-2-macroglobulin regulation both by direct protease inhibition and by removal from the extracellular space by receptor-mediated endocytosis. Finally, for the biomarker field, the analysis of alpha-2-macroglobulin/protease complexes with upgraded technology is advocated as a quotum for protease activation in human plasma samples.

Prediction of the early response to spironolactone in resistant hypertension by the combination of matrix metalloproteinase-9 activity and arterial stiffness parameters

AIMS

The aim of present study was to determine whether arterial stiffness assessed with the biochemical parameter active matrix metalloproteinase (MMP)-9 and the clinical parameters pulse pressure (PP) and pulse wave velocity predicts the response to spironolactone in resistant hypertension (RH).

METHODS AND RESULTS

Ambulatory blood pressure (BP) and active MMP-9 (measured by zymography and ELISA) were measured at baseline, and patients were classified as having pseudo-RH or RH. Patients with RH received spironolactone and the response was determined after 8 weeks by ambulatory BP monitoring: those who achieved BP goals were considered controlled (CRH) and those who did not were considered uncontrolled (UCRH). Plasma active MMP-9 was significantly higher in patients with RH than with pseudo-RH, and correlated with 24-hour systolic BP and PP. Receiver operating characteristic analysis indicated that active MMP-9 could predict the response to spironolactone, and its combination with 24-hour PP and pulse wave velocity significantly improved this prediction. Moreover, plasma of patients with UCRH induced the MMP-9 expression pathway.

CONCLUSION

We propose active MMP-9 as a useful biomarker to identify patients with RH who will not respond to spironolactone. Combining MMP-9 activity with classical arterial stiffness parameters improves the prediction of the clinical response to spironolactone and might contribute to guide the most appropriate therapeutic decisions for patients with RH.

Serum Biomarkers of Cardiovascular Remodelling Reflect Extra-Valvular Cardiac Damage in Patients with Severe Aortic Stenosis

In patients with aortic stenosis (AS), a novel staging classification of extra-valvular left and right heart damage with prognostic relevance was introduced in 2017. The aim of the study was to evaluate the biomarkers of cardiovascular tissue remodelling in relation to this novel staging classification. Patients were categorized according to the novel staging classification into stages 0 to 4. The levels of matrix metalloproteinase 9 (MMP-9), tissue inhibitor of metalloproteinases 1 (TIMP-1), B and C domain containing tenascin-C (B⁺ Tn-C, C⁺ Tn-C), the ED-A and ED-B domain containing fibronectin (ED-A⁺ Fn, ED-B⁺ Fn), endothelin 1 (ET-1) and neutrophil gelatinase-associated lipocalin (NGAL) were determined in serum by ELISA. There were significantly decreased serum levels of MMP-9 and increased levels of B⁺ Tn-C and C⁺ Tn-C when comparing stages 0 and 1 with stage 2, with no further dynamics in stages 3 and 4. In contrast, for TIMP-1, C⁺ Tn-C, ED-A⁺ Fn, ET-1 and NGAL, significantly increased serum levels could be detected in stages 3 and 4 compared to both stages 0 and 1 and stage 2. ED-A⁺ Fn and ET-1 could be identified as independent predictors of the presence of stage 3 and/or 4. To the best of our knowledge, this is the first study identifying novel serum biomarkers differentially reflecting the patterns of left and right heart extra-valvular damage in patients suffering from AS. Our findings might indicate a more precise initial diagnosis and risk stratification.

Plasma MMP-9 and TIMP-1 levels on ICU admission are associated with 30-day survival

Background

Matrix metalloproteinases (MMPs) are involved in systemic inflammatory responses and organ failure. The aim of this study was to evaluate early circulating plasma levels of MMP‑2, MMP‑9 and their inhibitors TIMP‑1 and TIMP‑2 and their prognostic significance in critically ill patients on admission to the intensive care unit (ICU).

Methods

In a single center prospective study 120 consecutive patients (72.5% male, mean age 66.8 ± 13.3 years, mean simplified acute physiology score [SAPS II] score 52.9 ± 21.9) were enrolled on transfer to the ICU of a cardiology department. The most common underlying conditions were cardiac diseases (n = 42.5%), respiratory failure (n = 10.8%) and sepsis (n = 6.7%). Blood samples were taken within 12 h of ICU admission. The MMP‑2, MMP‑9, TIMP‑1 and TIMP‑2 levels in plasma were evaluated in terms of 30-day survival, underlying condition and clinical score.

Results

On ICU admission 30-day survivors had significantly lower plasma MMP‑9 (odds ratio, OR 1.67 per 1 SD; 95% confidence interval, CI 1.10−2.53; p = 0.016) and TIMP‑1 (OR 2.15 per 1 SD; 95% CI 1.27−3.64; p = 0.004) levels than non-survivors; furthermore, MMP‑9 and TIMP‑1 correlated well with SAPS II (both p < 0.01). In patients with underlying cardiac diseases, MMP‑9 (p = 0.002) and TIMP‑1 (p = 0.01) were independent predictors of survival (Cox regression). No significant correlation was found between MMP‑2 and TIMP‑2 levels, MMP/TIMP ratios and 30-day mortality.

Conclusion

The MMP‑9 and TIMP‑1 levels are significantly elevated in acute critical care settings with increased short-term mortality risk, especially in patients with underlying heart disease. These findings support the value of MMPs and TIMPs as prognostic markers and potential therapeutic targets in conditions leading to systemic inflammation and acute organ failure.

Role of CyPA in cardiac hypertrophy and remodeling

Pathological cardiac hypertrophy is a complex process and eventually develops into heart failure, in which the heart responds to various intrinsic or external stress, involving increased interstitial fibrosis, cell death and cardiac dysfunction. Studies have shown that oxidative stress is an important mechanism for this maladaptation. Cyclophilin A (CyPA) is a member of the cyclophilin (CyPs) family. Many cells secrete CyPA to the outside of the cells in response to oxidative stress. CyPA from blood vessels and the heart itself participate in a variety of signaling pathways to regulate the production of reactive oxygen species (ROS) and mediate inflammation, promote cardiomyocyte hypertrophy and proliferation of cardiac fibroblasts, stimulate endothelial injury and vascular smooth muscle hyperplasia, and promote the dissolution of extracellular matrix (ECM) by activating matrix metalloproteinases (MMPs). The events triggered by CyPA cause a decline of diastolic and systolic function and finally lead to the occurrence of heart failure. This article aims to introduce the role and mechanism of CyPA in cardiac hypertrophy and remodeling, and highlights its potential role as a disease biomarker and therapeutic target.

Does Arterial Hypertension Affect Plasma Levels of Matrix Metalloproteinases and Their Tissue Inhibitors in Patients with Stable Coronary Artery Disease? A Preliminary Study

Background

Arterial hypertension (HT) is a serious and prevalent epidemiological factor in the development of coronary artery disease (CAD). Metalloproteinases (MMPs), especially MMP-2 and MMP-9, and their natural endogenous tissue inhibitors (TIMPs) are involved in the pathogenesis of HT and its complications. MMPs are also involved in the development of diabetes (DM), a risk factor for CAD. The aim of the study was to explore the influence of CAD, HT, and DM on changes in plasma levels of MMP-2 and MMP-9 and their inhibitor TIMP-4.

Methods and Results

The study involved 70 patients with stable CAD admitted for coronary angiography and 15 healthy subjects. Whole blood samples were collected prior to angiography. MMP-2, MMP-9, and TIMP-4 levels in plasma were estimated using ELISA tests. CAD patients showed a significantly increased level of TIMP-4 and decreased level of MMP-2 in comparison to healthy controls (p=0.011 and p=0.037, respectively). Concentration of MMP-2, MMP-9, and TIMP-4 did not differ in the group with and without hypertension. Patients with DM presented higher MMP-2 level than patients without DM (p < 0.001). Multiple regression analysis of the influence of independent variables such as CAD stage, DM, and HT on MMP-2, MMP-9, and TIMP-4 showed that only DM was independently associated with a higher level of MMP-2 (β = 0.42, R² = 0.17, p < 0.001).

Conclusion

Data showed that patients with CAD presented higher TIMP-4 and lower MMP-2 concentration regardless of HT and DM. HT had no effect on MMP-2, MMP-9, and TIMP-4 levels in serum. DM was independently associated with higher MMP-2 concentration; however, co-occurrence of CAD and DM was associated with the balance in the MMP-2 level. Concentration of MMP-9 did not change significantly in any of the analysed groups.

Leukocyte matrix metalloproteinase and tissue inhibitor gene expression patterns in children with primary hypertension

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play an important role in cardiovascular remodeling. The aim of the study was to analyze MMP/TIMP genes expression in peripheral blood leukocytes of 80 hypertensive children (15.1 ± 2.0 years) in comparison with age-matched 78 normotensive children (14.6 ± 2.0 years; n.s.). TIMP and MMP expression in peripheral blood leukocytes was assessed by quantitative real-time PCR. Hypertensive children independently of age, sex, and body mass index had greater expression of MMP-2 than normotensive controls (p = 0.0001). Patients with left ventricular hypertrophy had greater expression of MMP-14 than patients with normal left ventricular mass (p = 0.006) and TIMP-2 expression correlated with carotid wall cross-sectional area (p = 0.03; r = 0.238). MMP-14 expression correlated with BMI-SDS (p = 0.001; r = 0.371), waist circumference-SDS (p = 0.016; r = 0.290), hsCRP (p = 0.003; r = 0.350), serum HDL-cholesterol (p = 0.008; r = -0.304), and serum uric acid (p = 0.0001; r = 0.394). In conclusion, hypertensive adolescents presented significant alterations of MMP/TIMP expression pattern in comparison with normotensive peers. Moreover, altered MMP/TIMP expression was associated with hypertensive target organ damage and metabolic abnormalities.

Comparison of the perioperative time courses of matrix metalloproteinase-9 (MMP-9) and its inhibitor (TIMP-1) during carotid artery stenting (CAS) and carotid endarterectomy (CEA)

Background

Our aim was to compare the perioperative time courses of matrix metalloproteinase-9 (MMP-9) and its inhibitor (TIMP-1) in during carotid endarterectomy (CEA) and carotid artery stenting (CAS).

Methods

In our prospective study, twenty-five patients who were scheduled to undergo CAS were enrolled. We used a matched, historical CEA group as controls. Blood samples were collected at four time points: T1: preoperative; T2: 60 min after stent insertion; T3: first postoperative morning; and T4: third postoperative morning. Plasma MMP-9 and TIMP-1 levels were measured by ELISA.

Results

In the CEA group, the plasma levels of MMP-9 were significantly elevated at T3 compared to T1. In the CAS group, there was no significant difference in MMP-9 levels in the perioperative period. MMP-9 levels were significantly higher in the T3 samples of the CEA group compared to the CAS group. Significantly lower TIMP-1 levels were measured in both groups at T2 than at T1 in both groups. MMP-9/TIMP-1 at T3 was significantly higher than that at T1 in the CEA group compared to both T1 and the CAS group.

Conclusions

CAS triggers smaller changes in the MMP-9-TIMP-1 system during the perioperative period, which may correlate with a lower incidence of central nervous system complications. Additional studies as well as cognitive and functional surveys are warranted to determine the clinical relevance of our findings.

Trial registration

NIH U.S. National Library of Medicine, Clinicaltrials.gov,NCT03410576, 24.01.2018, Retrospectively registered

Matrix metalloproteinase-2 knockout prevents angiotensin II-induced vascular injury

Aims

Matrix metalloproteinases (MMPs) have been implicated in the development of hypertension in animal models and humans. Mmp2 deletion did not change Ang II-induced blood pressure (BP) rise. However, whether Mmp2 knockout affects angiotensin (Ang) II-induced vascular injury has not been tested. We sought to determine whether Mmp2 knockout will prevent Ang II-induced vascular injury.

Methods and results

A fourteen-day Ang II infusion (1000 ng/kg/min, SC) increased systolic BP, decreased vasodilatory responses to acetylcholine, induced mesenteric artery (MA) hypertrophic remodelling, and enhanced MA stiffness in wild-type (WT) mice. Ang II enhanced aortic media and perivascular reactive oxygen species generation, aortic vascular cell adhesion molecule-1 and monocyte chemotactic protein-1 expression, perivascular monocyte/macrophage and T cell infiltration, and the fraction of spleen activated CD4+CD69+ and CD8+CD69+ T cells, and Ly-6Chi monocytes. Study of intracellular signalling showed that Ang II increased phosphorylation of epidermal growth factor receptor and extracellular-signal-regulated kinase 1/2 in vascular smooth muscle cells isolated from WT mice. All these effects were reduced or prevented by Mmp2 knockout, except for systolic BP elevation. Ang II increased Mmp2 expression in immune cells infiltrating the aorta and perivascular fat. Bone marrow (BM) transplantation experiments revealed that in absence of MMP2 in immune cells, Ang II-induced BP elevation was decreased, and that when MMP2 was deficient in either immune or vascular cells, Ang II-induced endothelial dysfunction was blunted.

Conclusions

Mmp2 knockout impaired Ang II-induced vascular injury but not BP elevation. BM transplantation revealed a role for immune cells in Ang II-induced BP elevation, and for both vascular and immune cell MMP2 in Ang II-induced endothelial dysfunction.

Relationship of polymorphisms in the tissue inhibitor of metalloproteinase (TIMP)-1 and -2 genes with chronic heart failure

Dysregulated expression of tissue inhibitors of matrix metalloproteinases (TIMPs) is associated with systolic dysfunction and worsening heart failure (HF). However, no study has assessed the relationship between TIMP polymorphisms and chronic HF. In this study, 300 HF outpatients with reduced left ventricular ejection fraction and 304 healthy blood donors were genotyped for the 372 T > C polymorphism (Phe124Phe; rs4898) in the TIMP-1 gene and the −418 G > C polymorphism (rs8179090) in the TIMP-2 gene to investigate whether these polymorphisms are associated with HF susceptibility and prognosis. The genotype and allele frequencies of the 372 T > C polymorphism in HF patients were not significantly different from those observed among healthy subjects, and the C allele of the −418 G > C polymorphism was very rare in our population (frequency < 1%). After a median follow-up duration of 5.5 years, 121 patients (40.3%) died (67 of them from HF). Survival analysis did not show statistically significant differences in all-cause death and HF-related death between patients with and without the T allele (P > 0.05 for all comparisons). Thus, our findings do not support the hypothesis that the 372 T > C (Phe124Phe) polymorphism in the TIMP-1 gene and the −418 G > C polymorphism in the TIMP-2 gene are associated with HF susceptibility and prognosis in Southern Brazilians.

The association between circulating endostatin and a disturbed circadian blood pressure pattern in patients with type 2 diabetes

BACKGROUND

Endostatin, cleaved from collagen XVIII in the extracellular matrix, is a promising circulating biomarker for cardiovascular damage. It possesses anti-angiogenic and anti-fibrotic functions and has even been suggested to be involved in blood pressure regulation. Less is known if endostatin levels relate to circadian blood pressure patterns. In the present paper we studied the association between circulating levels of endostatin and nocturnal dipping in blood pressure.

METHODS

We used the CARDIPP-study, a cohort of middle aged, type 2 diabetics (n = 593, 32% women), with data on both 24-hour and office blood pressure, serum-endostatin, cardiovascular risk factors, and incident major cardiovascular events. Nocturnal dipping was defined as a >10% difference between day- and night-time blood pressures.

RESULTS

Two-hundred four participants (34%) were classified as non-dippers. The mean endostatin levels were significantly higher in non-dippers compared to dippers (mean ± standard deviation: 62.6 ± 1.8 µg/l vs. 58.7 ± 1.6 µg/l, respectively, p = .007). Higher serum levels of endostatin were associated with a diminished decline in nocturnal blood pressure adjusted for age, sex, HbA1c, mean systolic day blood pressure, hypertension treatment, glomerular filtration rate, and prevalent cardiovascular disease (regression coefficient per SD increase of endostatin -0.01, 95% CI, -0.02-(-0.001), p = .03). Structural equation modelling analyses suggest that endostatin mediates 7% of the association between non-dipping and major cardiovascular events.

CONCLUSION

We found an independent association between higher circulating levels of endostatin and a reduced difference between day- and night-time systolic blood pressure in patients with type 2 diabetes. Yet endostatin mediated only a small portion of the association between non-dipping and cardiovascular events arguing against a clinical utility of our findings.

Annexin A5 in treated hypertensive patients and its association with target organ damage

OBJECTIVE

Annexin A5 (AnxA5) has been previously linked to the presence of carotid and cardiac target organ damage (TOD) in the context of heart failure and rheumatologic patients. However, information is scant in the context of hypertension. Aim of our study was to evaluate AnxA5 in treated hypertension patients compared with normotensive controls and to determine whether it is associated with vascular and heart TOD evaluated as arterial stiffness, carotid plaque and left ventricular hypertrophy.

METHODS

We enrolled 123 consecutive treated hypertension and 124 normotensive controls. TOD was evaluated as pulse wave velocity (PWV, complior), left ventricular hypertrophy (echocardiography) and intima-media thickness and carotid plaque presence (ecographic methods). AnxA5 levels was dosed and compared in patients with and without hypertension and with and without TOD.

RESULTS

With similar age hypertension patients showed higher SBP, DBP and AnxA5 levels (13.9 ± 11.1 vs 10.1 ± 8.4 ng/ml, P < 0.001) compared with controls. Regarding TOD hypertension showed higher PWV (8.5 ± 1.8 vs 7.6 ± 1.5 m/s, P < 0.001) and LVMI (121.7 ± 29.3 vs 113.5 ± 21.1 g/m, P < 0.05), whereas carotid intima-media thickness was superimposable. AnxA5 correlates with PWV (r = 0.13, P < 0.05) and DBP (r = 0.15, P < 0.01), whereas it has never been found as a significant independent predictor of TOD in linear regression analysis.

CONCLUSION

Our data have shown that AnxA5 levels are increased in treated hypertension patients. In this condition, it is probably released in the plasma as a defensive mechanism through its anti-inflammatory and anticoagulants effects. We found a significant association with arterial stiffness, but AnxA5 was not found to be a significant predictor of TOD.

Cortisol/cortisone ratio and matrix metalloproteinase-9 activity are associated with pediatric primary hypertension

OBJECTIVE

To identify novel biomarkers associated with pediatric primary hypertension.

METHODS

We recruited 350 participants (4-16 years). Anthropometric parameters and aldosterone, plasma renin activity, cortisol, cortisone, Homeostasis Model Assessment Insulin Resistance (HOMA-IR), high-sensitivity C-reactive protein, adiponectin, IL-6, plasminogen activator inhibitor type 1 levels and matrix metalloproteinase-9 and matrix metalloproteinase-2 (MMP-9 and MMP-2) activities were measured. Genomic DNA was isolated. Patients with altered glucose metabolism, severe obesity [BMI-SD score (BMI-SDS) > 2.5], renovascular disease, primary aldosteronism and apparent mineralocorticoid excess syndrome were excluded.

RESULTS

In selected participants (n = 320), SBP was positively correlated with BMI-SDS (r = 0.382, P < 0.001), HOMA-IR (r = 0.211, P < 0.001), MMP-9 activity (r = 0.215, P < 0.001) and the cortisol/cortisone ratio (r = 0.231, P < 0.001). DBP showed similar correlations with these variables. No correlation was observed with aldosterone or plasma renin activity. Participants were categorized as hypertensive (n = 59) or nonhypertensive (n = 261). In the univariate analysis, hypertensive patients had higher BMI-SDS (P < 0.001), HOMA-IR (P < 0.001), high-sensitivity C-reactive protein (P < 0.001), MMP-9 activity (P < 0.001), plasminogen activator inhibitor type 1 (P < 0.001) and cortisol/cortisone ratio (P < 0.001) than nonhypertensive patients. Multiple regression analysis showed that the variables that remained associated with hypertension were higher BMI-SDS [odds ratio (OR) = 3.74; 95% confidence interval (CI) = 1.84-7.58], a higher cortisol/cortisone ratio (OR = 3.92; 95% CI = 1.98-7.71) and increased MMP-9 activity (OR = 4.23; 95% CI = 2.15-8.32).

CONCLUSION

We report that MMP-9 activity and the cortisol/cortisone ratio were higher in pediatric primary hypertensive patients, and these associations were independent of the effect of obesity. The potential role of these novel biomarkers in predicting hypertension risk and blood pressure regulation warrants further investigation.

Cerebrovascular gene expression in spontaneously hypertensive rats

Hypertension is a hemodynamic disorder and one of the most important and well-established risk factors for vascular diseases such as stroke. Blood vessels exposed to chronic shear stress develop structural changes and remodeling of the vascular wall through many complex mechanisms. However, the molecular mechanisms involved are not fully understood. Hypertension-susceptible genes may provide a novel insight into potential molecular mechanisms of hypertension and secondary complications associated with hypertension. The aim of this exploratory study was to identify gene expression differences in the middle cerebral arteries between 12-week-old male spontaneously hypertensive rats and their normotensive Wistar-Kyoto rats using an Affymetrix whole-transcriptome expression profiling. Quantitative PCR and western blotting were used to verify genes of interest. 169 genes were differentially expressed in the middle cerebral arteries from hypertensive compared to normotensive rats. The gene expression of 72 genes was decreased and the gene expression of 97 genes was increased. The following genes with a fold difference ≥1.40 were verified by quantitative PCR; Postn, Olr1, Fas, Vldlr, Mmp2, Timp1, Serpine1, Mmp11, Cd34, Ptgs1 and Ptgs2. The gene expression of Postn, Olr1, Fas, Vldlr, Mmp2, Timp1 and Serpine1 and the protein expression of LOX1 (also known as OLR1) were significantly increased in the middle cerebral arteries from spontaneously hypertensive rats compared to Wistar-Kyoto rats. In conclusion, the identified genes in the middle cerebral arteries from spontaneously hypertensive rats could be possible mediators of the vascular changes and secondary complications associated with hypertension. This study supports the selection of key genes to investigate in the future research of hypertension-induced end-organ damage.

The effect of antihypertensive treatment on arterial stiffness and serum concentration of selected matrix metalloproteinases

INTRODUCTION

The aim of the study was to assess the arterial stiffness and serum levels of selected metalloproteinases (MMPs) in hypertensive patients and their changes following antihypertensive therapy.

MATERIAL AND METHODS

The study group consisted of 95 patients with essential arterial hypertension (HT) stage 1 or 2 (mean age: 53.1 ±13.0 years). The control group consisted of 31 normotensives of the same age range. Hypertension patients were randomized to one of the following monotherapies for 6 months: quinapril, losartan, amlodipine, hydrochlorothiazide or bisoprolol. Carotid-femoral pulse wave velocity (PWV) was measured using a Complior device. Serum concentrations of MMPs (proMMP-1, MMP-2, MMP-3, MMP-9) and plasma concentration of tissue inhibitor of MMPs (TIMP-1) were measured using ELISA.

RESULTS

Pulse wave velocity and serum concentrations of MMP-2 and MMP-9 were higher in HT patients than in the control group. In HT patients PWV was significantly associated (R² = 0.41) with age (B = 0.408, p = 0.00027), systolic blood pressure (SBP) (B = 0.441, p = 0.0011), and MMP-3 (B = 0.204, p = 0.0459). After 6 months of treatment, regardless of the agent used, we observed a significant decrease of PWV, SBP, MMP-2 and MMP-3 and an increase of TIMP-1 plasma concentration. The decrease of PWV was significantly associated with a decrease of SBP (R² = 0.07, B = 0.260, p = 0.015) only.

CONCLUSIONS

In patients with arterial hypertension, beside age and systolic blood pressure, the determinants of arterial stiffness include serum MMP-3 concentration. For drugs compared in the study with the same hypotensive effect obtained, the arterial stiffness reduction effect is not dependent on the drug used. Systolic blood pressure is one of the independent factors responsible for the reduction of arterial stiffness in the course of antihypertensive treatment.

Matrix metalloproteinase-8 and tissue inhibitor of matrix metalloproteinase-1 predict incident cardiovascular disease events and all-cause mortality in a population-based cohort

Background Extracellular matrix degrading proteases and their regulators play an important role in atherogenesis and subsequent plaque rupture leading to acute cardiovascular manifestations. Design and methods In this prospective cohort study, we investigated the prognostic value of circulating matrix metalloproteinase-8, tissue inhibitor of matrix metalloproteinase-1 concentrations, the ratio of matrix metalloproteinase-8/ tissue inhibitor of matrix metalloproteinase-1 and, for comparison, myeloperoxidase and C-reactive protein concentrations for incident cardiovascular disease endpoints. The population-based FINRISK97 cohort comprised 7928 persons without cardiovascular disease at baseline. The baseline survey included a clinical examination and blood sampling. During a 13-year follow-up the endpoints were ascertained through national healthcare registers. The associations of measured biomarkers with the endpoints, including cardiovascular disease event, coronary artery disease, acute myocardial infarction, stroke and all-cause death, were analysed using Cox regression models. Discrimination and reclassification models were used to evaluate the clinical implications of the biomarkers. Results Serum tissue inhibitor of matrix metalloproteinase-1 and C-reactive protein concentrations were associated significantly with increased risk for all studied endpoints. Additionally, matrix metalloproteinase-8 concentration was associated with the risk for a coronary artery disease event, myocardial infarction and death, and myeloperoxidase concentration with the risk for cardiovascular disease events, stroke and death. The only significant association for the matrix metalloproteinase-8/ tissue inhibitor of matrix metalloproteinase-1 ratio was observed with the risk for myocardial infarction. Adding tissue inhibitor of matrix metalloproteinase-1 to the established risk profile improved risk discrimination of myocardial infarction ( p=0.039) and death (0.001). Both matrix metalloproteinase-8 (5.2%, p < 0.001) and tissue inhibitor of matrix metalloproteinase-1 (12.9%, p < 0.001) provided significant clinical net reclassification improvement for death. Conclusions Serum matrix metalloproteinase-8 and tissue inhibitor of matrix metalloproteinase-1 can be considered as biomarkers of incident cardiovascular disease events and death.

Gingival Fluid Inflammatory Biomarkers and Hypertension in African Americans

Hypertension and periodontitis are highly prevalent among African Americans. This cross-sectional study investigated the relationships among inflammatory biomarkers in the gingival fluid, periodontitis, and blood pressure in these individuals. Twenty-one subjects who reported a diagnosis of hypertension and a comparison group of 26 nonhypertensive participants were enrolled. All were African Americans, non-cigarette smoking, and free from other systemic illness. Blood pressure and body mass index were assessed. A comprehensive periodontal examination was performed. Gingival fluid was collected from 3 healthy sites and 3 diseased sites when available. Samples were assessed for 8-isoprostane, interleukin 1β, monocyte chemoattractant protein 1, tumor necrosis factor-alpha (TNFα), C-reactive protein (CRP), and matrix metalloproteinase 8. Regardless of hypertension status, diseased sites were associated with increased levels of these biomarkers. CRP and TNFα levels were also significantly higher in hypertensive than nonhypertensive individuals without diseased sites. After adjusting for demographics and body mass index, periodontal attachment loss was higher among hypertensive than nonhypertensive subjects. TNFα and CRP levels and hypertension were in the same association pathway with attachment loss. Elevated blood pressure may increase the risk of periodontitis through a localized inflammatory mechanism. Knowledge Transfer Statement: The results of this study can be used by clinicians to better understand the etiology and pathogenesis of periodontitis in hypertensive individuals in general and African Americans in particular. The information could lead to better management of periodontal disease.

Increased Circulating Tissue Inhibitor of Metalloproteinase-2 Is Associated With Resistant Hypertension

Resistant hypertension (RH) is associated with organ damage and cardiovascular risk. Evidence suggests the involvement of matrix metalloproteinase 2 (MMP-2) and tissue inhibitor of metalloproteinase 2 (TIMP-2) in hypertension and in cardiovascular remodeling. The aim of this study was to assess the levels of MMP-2 and TIMP-2 in RH and its relation with organ damage, including arterial stiffness and cardiac hypertrophy. MMP-2 and TIMP-2 levels were compared among 19 patients with normotension (NT), 116 with nonresistant hypertension (HTN) and 116 patients with resistant HTN (RH). MMP-2 levels showed no differences among NT, HTN, and RH groups, while TIMP-2 levels were higher in RH compared with HTN and NT groups (90.0 [76.1-107.3] vs 70.1 [57.7-88.3] vs 54.7 [40.9-58.1] ng/mL, P<.01), respectively. MMP-2/TIMP-2 ratio was reduced in the RH group compared with the HTN and NT groups (2.7 [1.9-3.4] vs 3.3 [2.6-4.2] vs 4.9 [4.5-5.3], P<.01), respectively. No associations were found between MMP-2 levels, TIMP-2, and MMP-2/TIMP-2 ratio with cardiac hypertrophy and arterial stiffness in the RH and HTN groups. Finally, in a regression analysis, reduced MMP-2/TIMP-2 ratio and increased TIMP-2 levels were independently associated with RH. The present findings provide evidence that TIMP-2 is associated with RH and might be a possible biomarker for screening RH patients.

Biomarkers of tissue remodeling predict survival in patients with pulmonary hypertension

BACKGROUND

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are involved in vascular and right ventricular remodeling in pulmonary hypertension (PH). MMP2, MMP9, TIMP1, and TIMP4 were measured in plasma and their potential as biomarkers for PH was evaluated.

METHODS

Consecutive patients undergoing right heart catheterization for suspected PH were included in this study (patients with mPAP ≥25mmHg were classed as having PH; those with mPAP <25mmHg served as non-PH controls). In total, 160 patients with PH (idiopathic pulmonary arterial hypertension, pulmonary arterial hypertension associated with connective tissue disease, chronic thromboembolic PH, and pulmonary venous hypertension) and 44 non-PH controls were included. Plasma from the time of PH diagnosis was analyzed for levels of MMP2, MMP9, TIMP1, and TIMP4 using enzyme immunoassays. Correlation analyses were performed with Pearson's or Spearman's coefficient, as appropriate. Mortality hazard ratios were derived using Cox regression analyses.

RESULTS

Plasma levels of MMP2, MMP9, TIMP1, and TIMP4 showed considerable overlap between patient groups. In patients with PH, MMP2, TIMP1, and TIMP4 levels correlated with hemodynamic parameters (p<0.05) and six minute walking distance (p<0.01). Patients with high (>median) MMP2 and TIMP1 plasma levels had significantly worse 5-year survival than patients with low (≤median) plasma levels (multivariate mortality hazard ratios: 2.69 and 4.46, respectively; p<0.01).

CONCLUSIONS

MMP2 and TIMP1 plasma levels in patients with PH reflect disease severity and predict outcome. Though not being of diagnostic value, elevated biomarker plasma levels are strongly associated with increased risk in patients with PH.

Vascular Aging: Lessons From Pediatric Hypertension

Hypertension (HTN) in children is associated with early vascular aging (EVA) and underlying immunologic-metabolic abnormalities and accelerated biological maturation. Morphologic and functional vascular changes underlying EVA and HTN in children resemble those seen in the elderly including but not limited to an increase in intima-media thickness (IMT) and arterial stiffness and endothelial dysfunction. Although progeria syndrome leading to EVA and the development of clinically manifested cardiovascular (CV) disease in the second decade of life is a rare hereditary disorder, primary HTN, which is also associated with EVA, is much more common (reported in up to 10% in adolescents). EVA associated with HTN in children leads to the premature development of target organ injury in childhood and CV events in early adulthood. Limited evidence from prospective observational studies in children and adolescents indicates that early lifestyle measures (low salt/low sugar intake and exercise) or pharmacologic treatment of HTN, or both, partially reverses morphologic and functional changes underlying EVA such as an increase in carotid IMT and pulse wave velocity, a decrease in flow-mediated dilation of the brachial artery, and an increase in oxidative stress and visceral fat. Future mechanistic and therapeutic clinical trials are desirable to assess the mechanisms and treatment strategies of EVA in the context of HTN in children and their effect on CV events in early adulthood.

Role of matrix metalloproteinase-9 in chronic kidney disease: a new biomarker of resistant albuminuria

Resistant albuminuria, developed under adequate chronic blockade of the renin-angiotensin system, is a clinical problem present in a small number of patients with chronic kidney disease (CKD). The mechanism underlying this resistant albuminuria remains unknown. Matrix metalloproteinases (MMPs) are involved in the pathophysiology of cardiovascular and renal diseases. In the present study we tested the role of MMPs in resistant albuminuria. First we evaluated gelatinase MMP-2 and MMP-9 activity by zymography in the Munich Wistar Frömter (MWF) rat, a model of progressive albuminuria, and subsequently in patients with resistant albuminuria. Markers of oxidative stress were observed in the kidneys of MWF rats, together with a significant increase in pro-MMP-2 and active MMP-9 forms. These changes were normalized together with reduced albuminuria in consomic MWF-8(SHR) rats, in which chromosome 8 of MWF was replaced with the respective chromosome from spontaneously hypertensive rats. The MMP-2 and MMP-9 protein levels were similar in patients with normal and resistant albuminuria; however, high circulating levels of collagen IV, a specific biomarker of tissue collagen IV degradation, were observed in patients with resistant albuminuria. These patients showed a significant increase in gelatinase MMP-2 and MMP-9 activity, but only a significant increase in the active MMP-9 form quantified by ELISA, which correlated significantly with the degree of albuminuria. Although the expression of the tissue inhibitor of MMP-9 (TIMP)-1 was similar, a novel AlphaLISA assay demonstrated that the MMP-9-TIMP-1 interaction was reduced in patients with resistant albuminuria. It is of interest that oxidized TIMP-1 expression was higher in patients with resistant albuminuria. Therefore, increased circulating MMP-9 activity is associated with resistant albuminuria and a deleterious oxidative stress environment appears to be the underlying mechanism. These changes might contribute to the progression of CKD in these patients.

Low levels of tissue inhibitor of metalloproteinase-2 at birth may be associated with subsequent development of bronchopulmonary dysplasia in preterm infants

Purpose

Bronchopulmonary dysplasia (BPD) is characterized by inflammation with proteolytic damage to the lung extracellular matrix. The results from previous studies are inconsistent regarding the role of proteinases and antiproteinases in the development of BPD. The aim of the present study was to investigate whether matrix metalloproteinase (MMP)-8, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-2, and TIMP-1 levels in the serum of preterm infants at birth are related to the development of BPD.

Methods

Serum was collected from 62 preterm infants at birth and analyzed for MMP-8, MMP-9, TIMP-2, and TIMP-1 by using enzyme-linked immunosorbent assay. MMPs and TIMPs were compared in BPD (n=24) and no BPD groups (n=38). Clinical predictors of BPD (sex, birth weight, gestational age, etc.) were assessed for both groups. The association between predictors and outcome, BPD, was assessed by using multivariate logistic regression.

Results

Sex, birth weight, and mean gestational age were similar between the groups. BPD preterm infants had significantly lower TIMP-2 levels at birth compared with no BPD preterm infants (138.1±23.0 ng/mL vs. 171.8±44.1 ng/mL, P=0.027). No significant difference was observed in MMP-8, MMP-9, and TIMP-1 levels between the two groups. Multivariate logistic regression analysis indicated that the TIMP-2 levels were predictive of BPD after adjusting for sex, birth weight, gestational age, proteinuric preeclampsia, and intraventricular hemorrhage (β=-0.063, P=0.041).

Conclusion

Low TIMP-2 serum levels at birth may be associated with the subsequent development of BPD in preterm infants.

Angiotensin-II induced hypertension and renovascular remodelling in tissue inhibitor of metalloproteinase 2 knockout mice

BACKGROUND

Sustained hypertension induces renovascular remodelling by altering extracellular matrix (ECM) components. Matrix metalloproteinases (MMPs) are Zn-dependent enzymes that regulate ECM turnover in concert with their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). Increased MMP-2 and MMP-9 have been implicated in hypertensive complications; however, the contribution of individual MMPs/TIMPs in renal remodelling has not been fully elucidated. The purpose of this study was to determine the effect of TIMP2 deficiency and thus MMP-2 on angiotensin-II (Ang-II) induced renal remodelling.

METHOD

C57BL/6J (wild-type) and TIMP2 knockout mice were infused with Ang-II at 250 ng/kg per min for 4 weeks. Blood pressure was measured weekly and end-point laser Doppler flowmetry was done to assess cortical blood flow. Immunohistochemical staining was performed for collagen and elastin analyses. The activity of MMP-9 and MMP-2 was determined by Gelatin zymography.

RESULTS

Ang-II induced similar elevation in mean blood pressure in TIMP2 and wild-type mice. In TIMP2 mice, Ang-II treatment was associated with a greater reduction in renal cortical blood flow and barium angiography demonstrated decreased vascular density compared with Ang-II treated wild-type mice. Peri-glomerular and vascular collagen deposition was increased and elastin content was decreased causing increased wall-to-lumen ratio in TIMP2 mice compared with wild-type mice receiving Ang-II. Ang-II increased the expression and activity of MMP-9 predominantly in TIMP2 mice than in wild-type mice.

CONCLUSION

These results suggest that TIMP2 deficiency exacerbates renovascular remodelling in agonist-induced hypertension by a mechanism that may, in part, be attributed to increased activity of MMP-9.

The Nuclear Factor kappaB Inhibitor Pyrrolidine Dithiocarbamate Prevents Cardiac Remodelling and Matrix Metalloproteinase-2 Up-Regulation in Renovascular Hypertension

Imbalanced matrix metalloproteinase (MMP) activity is involved in hypertensive cardiac hypertrophy. Pharmacological inhibition of nuclear factor kappaB (NF-кB) with pyrrolidine dithiocarbamate (PDTC) can prevent MMP up-regulation. We suggested that treatment with PDTC could prevent 2-kidney, 1-clip (2K1C) hypertension-induced left ventricular remodelling. Sham-operated controls or 2K1C rats with hypertension received either vehicle or PDTC (100 mg/kg/day) by gavage for 8 weeks. Systolic blood pressure was monitored every week. Histological assessment of left ventricles was carried out with haematoxylin/eosin sections, and fibrosis was quantified in picrosirius red-stained sections. Oxidative stress was evaluated in heart samples with the dihydroethidium probe. Cardiac MMP activity was determined by in situ zymography, and cardiac MMP-2 was assessed by immunofluorescence. 2K1C surgery significantly increased systolic blood pressure in the 2K1C vehicle. PDTC exerted antihypertensive effects after 2 weeks of treatment. Histology revealed increased left ventricular and septum wall thickness associated with augmented myocyte diameter in hypertensive rats, which were reversed by treatment with PDTC. Hypertensive rats developed pronounced cardiac fibrosis with increased interstitial collagen area, increased cardiac reactive oxygen species levels, gelatinase activity and MMP-2 expression. PDTC treatment decreased these alterations. These findings show that PDTC modulates myocardial MMP-2 expression and ameliorates cardiac remodelling in renovascular hypertension. These results suggest that interfering with MMP expression at transcriptional level may be an interesting strategy in the therapy of organ damage associated with hypertension.