Inhibition of matrix metalloproteinase-2 improves endothelial function and prevents hypertension in insulin-resistant rats

Role of Matrix Metalloproteinase-2 in the Development of Atherosclerosis among Patients with Coronary Artery Disease

Coronary artery disease (CAD) is a caused by atherosclerotic plaque buildup in the coronary arteries that supply blood and oxygen to the heart. Matrix metalloproteinase (MMP) is a family of zinc-dependent endopeptidase that is involved in various stages of atherosclerosis as demonstrated in in vitro and in vivo studies. MMP-2 is associated with both stable and unstable atherosclerotic plaque formation. The current review aimed to identify the role of MMP-2 in atherosclerosis development among CAD patients. Literature search was conducted through four online databases and only studies that were published from 2018 until February 2023 were included. The risk of bias was assessed by using the Newcastle-Ottawa Scale. A total of 10,622 articles were initially identified, and only eight studies that fulfilled the selection criteria were included in this review. The results showed that MMP-2 levels and activity were higher in patients with unstable CAD than those with stable CAD and healthy subjects. There was a significant association between MMP-2 levels and cardiovascular disease with MMP-14 levels, which is a pro-MMP-2 activator. In addition, two single nucleotide polymorphisms of the MMP-2 gene (rs243865 and rs243866) were significantly associated with the development of atherosclerosis. In conclusion, MMP-2 plays a crucial role in the development of atherosclerosis among patients with CAD and could be a potential target for CAD therapy.

Vascular adaptation to cancer beyond angiogenesis: The role of PTEN

Cancer is a public health problem, and it needs blood vessels to grow. Knowing more about the processes of vascular adaptation to cancer improves our chances of attacking it, since the tumor for its extension needs such adaptation to satisfy its progressive demand for nutrients. The main objective of this review is to present the reader with some fundamental molecular pathways for vascular adaptation to cancer, highlighting within them the regulatory role of homologous tensin and phosphatase protein (PTEN). Hence the review describes vascular adaptation to cancer through somewhat known processes, such as angiogenesis, but emphasizes others that are much less explored, namely the changes in vascular reactivity and remodeling of the vascular wall -intima-media thickness and adjustments in the extracellular matrix- The role of PTEN in physiological and pathological vascular mechanisms in different types of cancer is deepened, as a crucial mediator in vascular adaptation to cancer, and points pending further exploration in cancer vascularization are suggested.

Signaling pathways in vascular function and hypertension: molecular mechanisms and therapeutic interventions

Hypertension is a global public health issue and the leading cause of premature death in humans. Despite more than a century of research, hypertension remains difficult to cure due to its complex mechanisms involving multiple interactive factors and our limited understanding of it. Hypertension is a condition that is named after its clinical features. Vascular function is a factor that affects blood pressure directly, and it is a main strategy for clinically controlling BP to regulate constriction/relaxation function of blood vessels. Vascular elasticity, caliber, and reactivity are all characteristic indicators reflecting vascular function. Blood vessels are composed of three distinct layers, out of which the endothelial cells in intima and the smooth muscle cells in media are the main performers of vascular function. The alterations in signaling pathways in these cells are the key molecular mechanisms underlying vascular dysfunction and hypertension development. In this manuscript, we will comprehensively review the signaling pathways involved in vascular function regulation and hypertension progression, including calcium pathway, NO-NOsGC-cGMP pathway, various vascular remodeling pathways and some important upstream pathways such as renin-angiotensin-aldosterone system, oxidative stress-related signaling pathway, immunity/inflammation pathway, etc. Meanwhile, we will also summarize the treatment methods of hypertension that targets vascular function regulation and discuss the possibility of these signaling pathways being applied to clinical work.

Theories and Molecular Basis of Vascular Aging: A Review of the Literature from VascAgeNet Group on Pathophysiological Mechanisms of Vascular Aging

Vascular aging, characterized by structural and functional alterations of the vascular wall, is a hallmark of aging and is tightly related to the development of cardiovascular mortality and age-associated vascular pathologies. Over the last years, extensive and ongoing research has highlighted several sophisticated molecular mechanisms that are involved in the pathophysiology of vascular aging. A more thorough understanding of these mechanisms could help to provide a new insight into the complex biology of this non-reversible vascular process and direct future interventions to improve longevity. In this review, we discuss the role of the most important molecular pathways involved in vascular ageing including oxidative stress, vascular inflammation, extracellular matrix metalloproteinases activity, epigenetic regulation, telomere shortening, senescence and autophagy.

The Pathological Links between Adiposity and the Carpal Tunnel Syndrome

An association between obesity and carpal tunnel syndrome is found in many epidemiological studies. Therefore, there is a need to evaluate the physiopathological links that could explain the association between these two entities. Ectopic adipose tissue is responsible for metabolic syndrome and inflammation, and is a major risk factor for diabetes and cardiovascular diseases. Taking these elements into consideration, we conducted an extensive literature revision of the subject, considering as ectopic fat-related mechanisms the following: (a) the direct compression and the association with the metabolic syndrome of the fat deposition around the wrist, (b) the insulin resistance, dyslipidemia, inflammatory, and oxidative mechanisms related to the central deposition of the fat, (c) the impaired muscle contraction and metabolism related to myosteatosis. Each section presents the cellular pathways which are modified by the ectopic deposition of the adipose tissue and the impact in the pathogeny of the carpal tunnel syndrome. In conclusion, the experimental and clinical data support the epidemiological findings. Efforts to reduce the obesity epidemics will improve not only cardio-metabolic health but will reduce the burden of the disability-free life expectancy due to the carpal tunnel syndrome.

Developmental endothelial locus-1 protects from hypertension-induced cardiovascular remodeling via immunomodulation

The causative role of inflammation in hypertension-related cardiovascular diseases is evident and calls for development of specific immunomodulatory therapies. We tested the therapeutic efficacy and mechanisms of action of developmental endothelial locus-1 (DEL-1), an endogenous antiinflammatory factor, in angiotensin II– (ANGII–) and deoxycorticosterone acetate–salt–induced (DOCA-salt–induced) cardiovascular organ damage and hypertension. By using mice with endothelial overexpression of DEL-1 (EC-Del1 mice) and performing preventive and interventional studies by injecting recombinant DEL-1 in mice, we showed that DEL-1 improved endothelial function and abrogated aortic adventitial fibrosis, medial thickening, and loss of elastin. DEL-1 also protected the mice from cardiac concentric hypertrophy and interstitial and perivascular coronary fibrosis and improved left ventricular function and myocardial coronary perfusion. DEL-1 prevented aortic stiffness and abolished the progression of hypertension. Mechanistically, DEL-1 acted by inhibiting α_vβ₃ integrin–dependent activation of pro-MMP2 in mice and in human isolated aorta. Moreover, DEL-1 stabilized α_vβ₃ integrin–dependent CD25⁺FoxP3⁺ Treg numbers and IL-10 levels, which were associated with decreased recruitment of inflammatory cells and reduced production of proinflammatory cytokines in cardiovascular organs. The demonstrated effects and immune-modulating mechanisms of DEL-1 in abrogation of cardiovascular remodeling and progression of hypertension identify DEL-1 as a potential therapeutic factor.

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 knockdown blunts age-dependent carotid stiffness by decreasing elastin degradation and augmenting eNOS activation

AIMS

Arterial stiffness is a hallmark of vascular aging that precedes and strongly predicts the development of cardiovascular diseases. Age-dependent stiffening of large elastic arteries is primarily attributed to increased levels of matrix metalloproteinase-2 (MMP-2). However, the mechanistic link between age-dependent arterial stiffness and MMP-2 remains unclear. Thus, we aimed to investigate the efficacy of MMP-2 knockdown using small interfering RNA (siRNA) on age-dependent arterial stiffness.

METHODS AND RESULTS

Pulse wave velocity (PWV) was assessed in right carotid artery of wild type (WT) mice from different age groups. MMP-2 levels in the carotid artery and plasma of young (3 months) and old (20-25 months) WT mice were determined. Carotid PWV as well as vascular and circulating MMP-2 were elevated with increasing age in mice. Old WT mice (18-21-month-old) were treated for 4 weeks with either MMP-2 or scrambled (Scr) siRNA via tail vein injection. Carotid PWV was assessed at baseline, 2 and 4 weeks after start of the treatment. MMP-2 knockdown reduced vascular MMP-2 levels and attenuated age-dependent carotid stiffness. siMMP-2 treated mice showed increased elastin to collagen ratio, lower plasma desmosine (DES), enhanced phosphorylation of endothelial nitric oxide synthase (eNOS) and higher levels of vascular cyclic guanosine monophosphate (cGMP). An age-dependent increase in direct protein-protein interaction between MMP-2 and eNOS was also observed. Lastly, DES, an elastin breakdown product, was measured in a patient cohort (n = 64, 23-86 years old), where carotid-femoral PWV was also assessed; here, plasma levels of DES directly correlated with age and arterial stiffness.

CONCLUSION

MMP-2 knockdown attenuates age-dependent carotid stiffness by blunting elastin degradation and augmenting eNOS bioavailability. Given the increasing clinical use of siRNA technology, MMP2 knockdown should be investigated further as a possible strategy to mitigate age-dependent arterial stiffness and related CV diseases.

TRANSLATIONAL PERSPECTIVE

Arterial stiffness is a hallmark of vascular aging that precedes and strongly predicts the development of cardiovascular diseases. This study provides translational evidence to support a key role for MMP-2 on the development of age-associated arterial stiffness. Silencing of MMP-2 using siRNA technology shows an effect on aged mice where it attenuates age-dependent carotid stiffness by reducing elastin degradation and increasing eNOS bioavailability. Additionally, in humans we show that elastin breakdown increases with age and increased PWV. These findings indicate MMP-2 knockdown as a promising novel strategy to attenuate age-dependent arterial stiffness and cardiovascular diseases.

Combined effect of visit-to-visit variations in heart rate and systolic blood pressure on all-cause mortality in hypertensive patients

Elevated resting heart rate (RHR) and systolic blood pressure (SBP) are independent risk factors for all-cause mortality in hypertensive patients. However, the association of the visit-to-visit variation (VVV) in SBP and RHR with the risk of mortality in hypertensive patients remains unknown. The aim of this study was to investigate the effects of the VVVs in SBP and RHR on the risk of all-cause mortality. We enrolled 16,602 hypertensive patients from the Kailuan cohort study who underwent three health examinations from 2006 to 2010. The VVVs in SBP and RHR were defined by the coefficient of variation, standard deviation, variability independent of the mean, and average real variability. High variability was defined as the highest quartile of variability. Participants were classified numerically according to the number of high-variability parameters (e.g., a score of 2 indicated high variability in two parameters). Cox proportional hazards models were used to estimate hazard ratios for mortality. High VVVs in SBP and RHR were associated with an increased risk of all-cause mortality in hypertensive patients. In the multivariable-adjusted model comparing a score of 0 with a score of 2, the hazard ratios (95% confidence intervals (CIs)) for all-cause mortality were 1.38 (1.11-1.69), 1.52 (1.24-1.87), 1.32 (1.07-1.63), and 1.43 (1.16-1.75) using the coefficient of variation, standard deviation, variability independent of the mean, and average real variability, respectively. High VVVs in SBP and RHR constituted an independent risk factor for all-cause mortality in hypertensive patients. High VVVs in SBP and RHR additively increased the risk of all-cause mortality in hypertensive patients.

Matrix Metalloproteinases and Arterial Hypertension: Role of Oxidative Stress and Nitric Oxide in Vascular Functional and Structural Alterations

Various pathophysiological mechanisms have been implicated in hypertension, but those resulting in vascular dysfunction and remodeling are critical and may help to identify critical pharmacological targets. This mini-review article focuses on central mechanisms contributing to the vascular dysfunction and remodeling of hypertension, increased oxidative stress and impaired nitric oxide (NO) bioavailability, which enhance vascular matrix metalloproteinase (MMP) activity. The relationship between NO, MMP and oxidative stress culminating in the vascular alterations of hypertension is examined. While the alterations of hypertension are not fully attributable to these pathophysiological mechanisms, there is strong evidence that such mechanisms play critical roles in increasing vascular MMP expression and activity, thus resulting in abnormal degradation of extracellular matrix components, receptors, peptides, and intracellular proteins involved in the regulation of vascular function and structure. Imbalanced vascular MMP activity promotes vasoconstriction and impairs vasodilation, stimulating vascular smooth muscle cells (VSMC) to switch from contractile to synthetic phenotypes, thus facilitating cell growth or migration, which is associated with the deposition of extracellular matrix components. Finally, the protective effects of MMP inhibitors, antioxidants and drugs that enhance vascular NO activity are briefly discussed. Newly emerging therapies that address these essential mechanisms may offer significant advantages to prevent vascular remodeling in hypertensive patients.

CD44, a Predominant Protein in Methylglyoxal-Induced Secretome of Muscle Cells, is Elevated in Diabetic Plasma

Methylglyoxal (MG), a glycolytic intermediate and reactive dicarbonyl, is responsible for exacerbation of insulin resistance and diabetic complication. In this study, MG-induced secretome of rat muscle cells was identified and relatively quantified by SWATH-MS. A total of 643 proteins were identified in MG-induced secretome, of which 82 proteins were upregulated and 99 proteins were downregulated by more than 1.3-fold in SWATH analysis. Further, secretory proteins from the classical secretory pathway and nonclassical secretory pathway were identified using SignalP and SecretomeP, respectively. A total of 180 proteins were identified with SignalP, and 113 proteins were identified with SecretomeP. The differentially expressed proteins were functionally annotated by KEGG pathway analysis using Cytoscape software with plugin clusterMaker. The differentially expressed proteins were found to be involved in various pathways like extracellular matrix (ECM)-receptor interaction, leukocyte transendothelial migration, fluid shear stress and atherosclerosis, complement and coagulation cascades, and lysosomal pathway. Since the MG levels are high in diabetic conditions, the presence of MG-induced secreted proteins was inspected by profiling human plasma of healthy and diabetic subjects (n = 10 each). CD44, a predominant MG-induced secreted protein, was found to be elevated in the diabetic plasma and to have a role in the development of insulin resistance.

Phyto-derived Products as Matrix Metalloproteinases Inhibitors in Cardiovascular Diseases

Matrix metalloproteinases (MMPs) are enzymes that present a metallic element in their structure. These enzymes are ubiquitously distributed and function as extracellular matrix (ECM) remodelers. MMPs play a broad role in cardiovascular biology regulating processes such as cell adhesion and function, cellular communication and differentiation, integration of mechanical force and force transmission, tissue remodeling, modulation of damaged-tissue structural integrity, cellular survival or apoptosis and regulation of inflammation-related cytokines and growth factors. MMPs inhibition and downregulation are correlated with minimization of cardiac damage, i.e., Chinese herbal medicine has shown to stabilize abdominal aorta aneurysm due to its antiinflammatory, antioxidant and MMP-2 and 9 inhibitory properties. Thus phyto-derived products rise as promising sources for novel therapies focusing on MMPs inhibition and downregulation to treat or prevent cardiovascular disorders.

Effect of High Intensity Interval Training on Matrix Metalloproteinases in Women with Breast Cancer Receiving Anthracycline-Based Chemotherapy

Anthracycline chemotherapy is commonly used to treat breast cancer yet may increase the level of matrix metalloproteinases (MMP) -2 and -9, which increase the risk of atherosclerosis. While exercise has been shown to reduce the level of MMP in patients with diabetes, high intensity interval training (HIIT) has not been utilized to improve level of MMP in women with breast cancer receiving anthracycline chemotherapy. Thirty women were randomized to either 8-week HIIT or control (CON) group. The CON group was offered the HIIT intervention after 8 weeks. MMP-1, -2 -7, -9, tissue inhibitor of MMP (TIMP) -1, and-2 were measured at baseline and post-intervention. Repeated measures ANCOVA and paired t-test were performed to assess changes in MMP and TIMP. Post-intervention, no significant between-group differences were observed for MMP and TIMP. However, within-group decrease in MMP-9 was observed in the HIIT group [104.3(51.9) to 65.2(69.1); P = 0.01]. MMP-9 in the CON group was not significantly changed [115.5(47.2) to 90.4(67.9);]. MMP-2 significantly increased in both the HIIT group [76.6(11.2) to 83.2(13.1); P = 0.007) and the CON group [69.0(8.9) to 77.6(11.1) P = 0.003). It is unclear whether an 8-week HIIT intervention influences MMP-9 in breast cancer patients undergoing anthracycline chemotherapy. Additional investigations are required to understand the exercise-induced changes in MMP-2 and -9 in women undergoing anthracycline chemotherapy.

Rhodiola crenulata Suppresses High Glucose-Induced Matrix Metalloproteinase Expression and Inflammatory Responses by Inhibiting ROS-Related HMGB1-TLR4 Signaling in Endothelial Cells

Rhodiola crenulata, a popular folk medicine for anti-altitude sickness in Tibet, has been shown to have protective effects against high glucose (HG)-induced endothelial cell dysfunction in human umbilical vein endothelial cells (HUVECs). However, its mechanisms of action are unclear. Here, we aimed to examine the effects and the mechanisms of action of Rhodiola crenulata extract (RCE) on matrix metalloproteinases (MMPs) and inflammatory responses under HG conditions. HUVECs were pretreated with RCE or untreated and then exposed to 33[Formula: see text]mM glucose medium for 24[Formula: see text]h. The levels of oxidative stress markers, MMPs, endogenous tissue inhibitors of MMPs (TIMPs), and adhesion molecules were determined. Zymography assays were also carried out. We found that RCE significantly decreased HG-induced increases in reactive oxygen species (ROS) and activation of MAPK and NF-[Formula: see text]B pathways. In addition, RCE not only significantly reduced the expression and activities of MMPs but also upregulated TIMP protein levels. Consistently, HG-induced activation of the toll-like receptor 4 (TLR4)/myeloid differentiation primary response protein (MyD88) signaling pathway, intracellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and high mobility group box 1 (HMGB1) as well as endothelial cell apoptosis was inhibited by RCE treatment. RCE exerts protective effects on endothelial cells against HG insult, partially by suppressing the HMGB1/TLR4 axis. These findings indicate that Rhodiola crenulata may be a potential therapeutic agent for diabetes-associated vascular diseases.

Matrix metalloproteinase (MMP)-2 activation by oxidative stress decreases aortic calponin-1 levels during hypertrophic remodeling in early hypertension

Hypertension is characterized by maladaptive vascular remodeling and enhanced oxidative stress in the vascular wall. Peroxynitrite may directly activate latent matrix metalloproteinase (MMP)-2 in vascular smooth muscle cells (VSMC) by its S-glutathiolation. MMP-2 may then proteolyze calponin-1 in aortas from hypertensive animals, which stimulates VSMC proliferation and medial hypertrophy. Calponin-1 is an intracellular protein which helps to maintain VSMC in their differentiated (contractile) phenotype. The present study therefore investigated whether aortic MMP-2 activity is increased by oxidative stress in early hypertension and then contributes to hypertrophic arterial remodeling by reducing the levels of calponin-1. Male Wistar rats were submitted to the two kidney, one clip (2 K-1C) model of hypertension or sham surgery and were treated daily with tempol (18 mg/kg/day) or its vehicle (water) by gavage from the third to seventh day post-surgery. Systolic blood pressure (SBP) was daily assessed by tail-cuff plethysmography. After one week, aortas were removed to perform morphological analysis with hematoxylin and eosin staining and to analyze reactive oxygen‑nitrogen species levels by dihydroethidium and immunohistochemistry for nitrotyrosine. MMP-2 activity was analyzed by in situ and gelatin zymography and its S-glutathiolation was analyzed by Western blot for MMP-2 of anti-glutathione immunoprecipitates. Calponin-1 levels were identified in aortas by immunofluorescence. SBP increased by approximately 50 mmHg at the first week in 2 K-1C rats which was unaffected by tempol. However, tempol ameliorated the hypertension-induced increase in arterial media-to-lumen ratio and hypertrophic remodeling. Tempol also decreased hypertension-induced aortic oxidative stress and the enhanced MMP-2 activity. S-glutathiolation may be a potential mechanism by which oxidative stress activates MMP-2 in aortas of 2 K-1C rats. Furthermore, calponin-1 was decreased in aortas from 2 K-1C rats and tempol prevented this. In conclusion, oxidative stress may contribute to the increase in aortic MMP-2 activity, possibly by S-glutathiolation, and this may result in calponin-1 loss and maladaptive vascular remodeling in early hypertension.

Oxidative stress and vascular stiffness in hypertension: A renewed interest for antioxidant therapies?

Since the first successful launch of the Veterans Administration(VA) cooperative studies in the late 1960s, the increasing access to blood pressure lowering medications has significantly contributed to improving longevity and quality of life in hypertensive patients. Since then, insights into the pathogenesis of hypertension have shown a mechanistic role for reactive oxygen species (ROS) in all phases of disease progression, suggesting the potential utility of antioxidant therapies to counteract symptoms and, at the same time, treat a fundamental mechanism of the disease. Despite these progresses, hypertension still remains the main contributor to the global incidence of cardiovascular disease and the leading cause of morbidity and mortality worldwide. We here briefly review and update the role of ROS and ROS-dependent metalloproteinase activation in the maladaptive remodeling of the vascular wall in hypertension. Such understanding should provide new Potential sites of action for antioxidant therapies as an integrated therapeutic approach to hypertension and its consequences.

Effects of high-intensity interval training on vascular function in breast cancer survivors undergoing anthracycline chemotherapy: design of a pilot study

INTRODUCTION

Cardiovascular disease (CVD) mortality is higher among breast cancer survivors (BCS) who receive chemotherapy compared with those not receiving chemotherapy. Anthracycline chemotherapy is of particular concern due to anthracycline-related impairment of vascular endothelial cells and dysregulation of the extracellular matrix. One strategy proven to offset these impairments is a form of exercise known as high-intensity interval training (HIIT). HIIT improves endothelial function in non-cancer populations by decreasing oxidative stress, the main contributor to anthracycline-induced vascular dysfunction. The purpose of this pilot study is to assess the feasibility of an 8-week HIIT, as well as the HIIT effects on endothelial function and extracellular matrix remodelling, in BCS undergoing anthracycline chemotherapy.

METHODS AND ANALYSIS

Thirty BCS are randomised to either HIIT, an 8-week HIIT intervention occurring three times per week (seven alternating bouts of 90% of peak power output followed by 10% peak power output), or delayed group (DEL). Feasibility of HIIT is assessed by (1) the percentage of completed exercise sessions and (2) the number of minutes of exercise completed over the course of the study. Vascular function is assessed using brachial artery flow-mediated dilation and carotid intima media thickness. Extracellular matrix remodelling is assessed by the level of matrix metalloproteinases in the plasma. A repeated-measures analysis of covariance model will be performed with group (HIIT and DEL group) and time (pre/post assessment) as independent factors. We hypothesise that HIIT will be feasible in BCS undergoing anthracycline chemotherapy, and that HIIT will improve endothelial function and extracellular matrix remodelling, compared with the DEL group. Success of this study will provide evidence of feasibility and efficacy to support a larger definitive trial which will impact cancer survivorship by decreasing anthracycline-induced vascular dysfunction, thereby benefiting cardiovascular markers that are related to CVD risk.

ETHICS AND DISSEMINATION

This trial was approved by the University of Southern California Institutional Review Board (HS-15-00227).

TRIAL REGISTRATION NUMBER

NCT02454777; Pre-results.

MMP-2 and MMP-9 contribute to the angiogenic effect produced by hypoxia/15-HETE in pulmonary endothelial cells

Matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) are the predominant gelatinases in the developing lung. Studies have shown that the expression of MMP-2 and MMP-9 is upregulated in hypoxic fibroblasts, 15-hydroxyeicosatetraenoic acid (15-HETE) regulated fibroblasts migration via modulating MMP-2 or MMP-9, and that hypoxia/15-HETE is a predominant contributor to the development of pulmonary arterial hypertension (PAH) through increased angiogenesis. However, the roles of MMP-2 and MMP-9 in pulmonary arterial endothelial cells (PAECs) angiogenesis as well as the molecular mechanism of hypoxia-regulated MMP-2 and MMP-9 expression have not been identified. The aim of this study was to investigate the role of MMP-2 and MMP-9 in PAEC proliferation and vascular angiogenesis and to determine the effects of hypoxia-induced 15-HETE on the expression of MMP-2 and MMP-9. Western blot, immunofluorescence, and real-time PCR were used to measure the expression of MMP-2 and MMP-9 in hypoxic PAECs. Immunohistochemical staining, flow cytometry, and tube formation as well as cell proliferation, viability, scratch-wound, and Boyden chamber migration assays were used to identify the roles and relationships between MMP-2, MMP-9, and 15-HETE in hypoxic PAECs. We found that hypoxia increased MMP-2 and MMP-9 expression in pulmonary artery endothelium both in vivo and in vitro in a time-dependent pattern. Moreover, administration of the MMP-2 and MMP-9 inhibitor MMI-166 significantly reversed hypoxia-induced increases in right ventricular systemic pressure (RVSP), right ventricular function, and thickening of the tunica media. Furthermore, up-regulation of MMP-2 and MMP-9 expression was induced by 15-HETE, which regulates PAEC proliferation, migration, and cell cycle transition that eventually leads to angiogenesis. Our study demonstrated that hypoxia increases the expression of MMP-2 and MMP-9 through the 15-lipoxygenase/15-HETE pathway, and that MMP-2 and MMP-9 promote PAEC angiogenesis. These findings suggest that MMP-2 and MMP-9 may serve as new potential therapeutic targets for the treatment of PAH.

Gelatinases and their tissue inhibitors in a group of subjects with obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is associated with an elevated risk of cardiovascular events and stroke. Matrix metalloproteinases (MMPs) are endopeptidases involved in extracellular matrix degradation and then in the development and progression of cardiovascular diseases. Our aim was to evaluate plasma levels of gelatinases (MMP-2 and MMP-9) and their tissue inhibitors (TIMP-1 and TIMP-2) in a group of subjects with OSAS. We enrolled 48 subjects (36 men and 12 women; mean age 49.7 ± 14.68 yrs) with OSAS diagnosed with a 1-night cardiorespiratory study and then we subdivided these subjects into two subgroups according to the apnea/hypopnea index (AHI): Low (L = 21 subjects with AHI <30) and High (H = 27 subjects with AHI >30). We measured plasma concentration of the gelatinases and their inhibitors using ELISA kits. We observed a significant increase in plasma concentration of MMP-9, MMP-2, TIMP-1 and TIMP-2 in the entire group of OSAS subjects and in the two subgroups, with higher levels in the H in comparison with the L subgroup. In the whole group of OSAS subjects we also noted a significant decrease in MMP-9/TIMP-1 ratio in comparison with normal controls. Only MMP-9 was significantly correlated with the severity of the disease, expressed as AHI, with the oxygen desaturation index and also with the mean oxygen saturation. MMPs pattern is altered in OSAS and significantly influenced by the severity of the disease; it probably contributes to the vascular remodeling that leads to the atherosclerotic disease and cardiovascular complications.

Proteolytic receptor cleavage in the pathogenesis of blood rheology and co-morbidities in metabolic syndrome. Early forms of autodigestion

Abnormal blood rheological properties seldom occur in isolation and instead are accompanied by other complications, often designated as co-morbidities. In the metabolic syndrome with complications like hypertension, diabetes and lack of normal microvascular blood flow, the underlying molecular mechanisms that simultaneously lead to elevated blood pressure and diabetes as well as abnormal microvascular rheology and other cell dysfunctions have remained largely unknown. In this review, we propose a new hypothesis for the origin of abnormal cell functions as well as multiple co-morbidities. Utilizing experimental models for the metabolic disease with diverse co-morbidities we summarize evidence for the presence of an uncontrolled extracellular proteolytic activity that causes ectodomain receptor cleavage and loss of their associated cell function. We summarize evidence for unchecked degrading proteinase activity, e.g. due to matrix metalloproteases, in patients with hypertension, Type II diabetes and obesity, in addition to evidence for receptor cleavage in the form of receptor fragments and decreased extracellular membrane expression levels. The evidence suggest that a shift in blood rheological properties and other co-morbidities may in fact be derived from a common mechanism that is due to uncontrolled proteolytic activity, i.e. an early form of autodigestion. Identification of the particular proteases involved and the mechanisms of their activation may open the door to treatment that simultaneously targets multiple co-morbidities in the metabolic syndrome.

Matrix metalloproteinase (MMP)-2 decreases calponin-1 levels and contributes to arterial remodeling in early hypertension

Increased matrix metalloproteinase (MMP)-2 is implicated in the vascular remodeling of hypertension. Calponin-1 is a contractile protein, and its absence is associated with vascular smooth muscle cell (VSMC) phenotype switch, which leads to migration and remodeling. We evaluated whether increased MMP-2 activity precedes chronic vascular remodeling by decreasing calponin-1 and inducing VSMC proliferation. Sham or two kidney-one clip (2K1C) rats were treated with doxycycline at 30mg/kg/day. Systolic blood pressure was increased in the 2K1C rats after 1 and 2weeks post-surgery, and doxycycline was effective to reduce it only at 2weeks of hypertension (p<0.05). Increased activity of MMP-2 was observed in aortas from 2K1C at 1 and 2weeks of hypertension, followed by increased VSMC proliferation, and those effects were abolished by treating 2K1C rats with doxycycline (p<0.05). Increased aortic media to lumen ratio started to emerge in 2K1C rats at 1week of hypertension, and it was established by 2weeks. MMP-2 and calponin-1 co-localized in the cytosol of VSMC. Aortas from 2K1C rats showed a significant reduction in calponin-1 levels at 1week of hypertension, and doxycycline prevented its loss (p<0.05). However, at 2weeks of hypertension, calponin-1 was upregulated in 2K1C (p<0.05 vs. Sham groups). The mRNA levels of calponin-1 were not altered in the aortas of 2K1C at 1week of hypertension. MMP-2 may contribute to the post-translational decrease in calponin-1, thus culminating in hypertension-induced maladaptive arterial remodeling.

The mechanisms underlying fructose-induced hypertension: a review

We are currently in the midst of an epidemic of metabolic disorders, which may, in part, be explained by excess fructose intake. This theory is supported by epidemiological observations as well as experimental studies in animals and humans. Rising consumption of fructose has been matched with growing rates of hypertension, leading to concern from public health experts. At this stage, the mechanisms underlying fructose-induced hypertension have not been fully characterized and the bulk of our knowledge is derived from animal models. Animal studies have shown that high-fructose diets up-regulate sodium and chloride transporters, resulting in a state of salt overload that increases blood pressure. Excess fructose has also been found to activate vasoconstrictors, inactivate vasodilators, and over-stimulate the sympathetic nervous system. Further work is required to determine the relevance of these findings to humans and to establish the level at which dietary fructose increases the risk of developing hypertension

Antioxidant response of osteoblasts to doxycycline in an inflammatory model induced by C-reactive protein and interleukin-6

Objectives: Investigation of osteoblastic responses to oxidative stress, induced by C-reactive protein (CRP) and IL-6 and ameliorating effects of doxycycline (Dox); using assays for 5-alpha dihydrotestosterone (DHT) as an antioxidant marker of healing. IL-6 and CRP are risk markers of periodontitis and prevalent comorbidities in periodontitis subjects. Methods: Confluent monolayer cultures of osteoblasts were incubated with radiolabelled testosterone (14C-T) as substrate, in the presence or absence (Control) of pre-determined optimal concentrations of CRP, IL-6, Dox; alone and in combination (n=8) for 24h in MEM. The eluent was solvent-extracted for steroid metabolites. They were separated using TLC in a benzene/ acetone solvent system 4:1 v/v; and quantified using radioisotope scanning. The identity of formed metabolites was confirmed using the mobility of cold standards added to the samples and disclosed in iodine. Further confirmation of the authenticity of DHT was carried out by combined gas chromatrography-mass spectrometry, after derivatization to pentafluorobenzyloxime trimethyl silyl ether. Results: The yields of DHT from 14C-testosterone showed 2-fold and 1.8-fold- inhibition in response to IL-6 and CRP respectively and 28% stimulation in response to Dox, via the 5-alpha reductase pathway. The combination of IL-6 + CRP showed a 2-fold reduction in the yields of DHT, elevated to control values when combined with Dox (n=8; p<0.001). Yields of 4-androstenedione showed an inverse relationship to those of DHT, in response to the agents tested, in keeping with the 17-beta hydroxysteroid dehydrogenase pathway. Conclusions: Inhibition of DHT synthesis in osteoblasts by IL-6 and CRP was overcome by doxycycline. Oxidative actions of IL-6 and CRP; and antioxidant actions of Dox are reinforced by the metabolic yields of DHT in response to agents tested. Using a novel metabolically active model allows closer extrapolation to in vivo conditions; in the context of adjunctive therapeutic applications for periodontitis and prevalent comorbidities.

Blockade of MMP14 activity in murine breast carcinomas: implications for macrophages, vessels, and radiotherapy

BACKGROUND

Matrix metalloproteinase (MMP) 14 may mediate tumor progression through vascular and immune-modulatory effects.

METHODS

Orthotopic murine breast tumors (4T1 and E0771 with high and low MMP14 expression, respectively; n = 5-10 per group) were treated with an anti-MMP14 inhibitory antibody (DX-2400), IgG control, fractionated radiation therapy, or their combination. We assessed primary tumor growth, transforming growth factor β (TGFβ) and inducible nitric oxide synthase (iNOS) expression, macrophage phenotype, and vascular parameters. A linear mixed model with repeated observations, with Mann-Whitney or analysis of variance with Bonferroni post hoc adjustment, was used to determine statistical significance. All statistical tests were two-sided.

RESULTS

DX-2400 inhibited tumor growth compared with IgG control treatment, increased macrophage numbers, and shifted the macrophage phenotype towards antitumor M1-like. These effects were associated with a reduction in active TGFβ and SMAD2/3 signaling. DX-2400 also transiently increased iNOS expression and tumor perfusion, reduced tissue hypoxia (median % area: control, 20.2%, interquartile range (IQR) = 6.4%-38.9%; DX-2400: 1.2%, IQR = 0.2%-3.2%, P = .044), and synergistically enhanced radiation therapy (days to grow to 800mm(3): control, 12 days, IQR = 9-13 days; DX-2400 plus radiation, 29 days, IQR = 26-30 days, P < .001) in the 4T1 model. The selective iNOS inhibitor, 1400W, abolished the effects of DX-2400 on vessel perfusion and radiotherapy. On the other hand, DX-2400 was not capable of inducing iNOS expression or synergizing with radiation in E0771 tumors.

CONCLUSION

MMP14 blockade decreased immunosuppressive TGFβ, polarized macrophages to an antitumor phenotype, increased iNOS, and improved tumor perfusion, resulting in reduced primary tumor growth and enhanced response to radiation therapy, especially in high MMP14-expressing tumors.

Effects of monocyte-endothelium interactions on the expression of type IV collagenases in monocytes

The adhesion of monocytes to endothelial cells is one of the early stages in the development of atherosclerosis. The expression of type IV collagenases, which include matrix metalloproteinase (MMP)-2 and MMP-9, in monocytes is hypothesized to play an important role in monocyte infiltration and transformation into foam cells. The aim of the present study was to examine the effects of monocyte-endothelium interactions on the expression levels of type IV collagenases and their specific inhibitors in monocytes, and to investigate the roles of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in this process. Monocytes were single-cultured or co-cultured with endothelial cells. The expression of the type IV collagenases, MMP-2 and MMP-9, and their specific inhibitors, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2, in monocytes was determined by immunohistochemistry followed by image analysis. The expression levels of MMP-2 and MMP-9 were found to be low in the single-culture monocytes, but increased significantly when the monocytes and endothelial cells were co-cultured. However, treatment with monoclonal TNF-α or IL-1β antibodies partially inhibited the upregulated expression of MMP-2 and MMP-9 in the co-cultured monocytes. Expression of TIMP-1 and TIMP-2 was observed in the single monocyte culture, and a small increase in the expression levels was observed when the monocytes were co-cultured with endothelial cells. Therefore, monocyte-endothlium interactions were shown to increase the expression of type IV collagenases in monocytes, resulting in the loss of balance between MMP-2 and -9 with TIMP-1 and -2. In addition, TNF-α and IL-1β were demonstrated to play important roles in this process.

Combined subthreshold dose inhibition of myosin light chain phosphorylation and MMP-2 activity provides cardioprotection from ischaemic/reperfusion injury in isolated rat heart

BACKGROUND AND PURPOSE

Phosphorylation and degradation of myosin light chain 1 (MLC1) during myocardial ischaemia/reperfusion (I/R) injury is a well-established phenomenon. It has been established that MMP-2 is involved in MLC1 degradation and that this degradation is increased when MLC1 is phosphorylated. We hypothesized that simultaneous inhibition of MLC1 phosphorylation and MMP-2 activity will protect hearts from I/R injury. As phosphorylation of MLC1 and MMP-2 activity is important for normal heart function, we used a cocktail consisting combination of low (subthreshold for any protective effect alone) doses of MLC kinase, MMP-2 inhibitors and subthreshold dose of an MLC phosphatase activator.

EXPERIMENTAL APPROACH

Isolated rat hearts were subjected to 20 min of global, no-flow ischaemia and 30 min reperfusion in the absence and presence of inhibitors of MLC1 phosphorylation and degradation.

KEY RESULTS

The recovery of cardiac function was improved in a concentration-dependent manner by the MLC kinase inhibitor, ML-7 (1-5 μM), the MLC phosphatase activator, Y-27632 (0.05-1 μM) or the MMP inhibitor, doxycycline (Doxy, 1-30 μM). Co-administration of subthreshold doses of ML-7 (1 μM) and Y-27632 (0.05 μM) showed a potential synergistic effect in protecting cardiac contractility and MLC1 levels in I/R hearts. Further combination with a subthreshold concentration of Doxy (1 μM) showed additional protection that resulted in full recovery to control levels.

CONCLUSIONS AND IMPLICATIONS

The results of this study exemplify a novel low-dose multidrug approach to pharmacological prevention of reperfusion injury that will enable a reduction of unwanted side effects and/or cytotoxicity associated with currently available MMP-2 and kinase inhibiting drugs.

Matrix metalloproteinases are involved in cardiovascular diseases

This MiniReview describes the essential biochemical and molecular aspects of matrix metalloproteinases (MMPs) and briefly discusses how they engage in different diseases, with particular emphasis on cardiovascular diseases. There is compelling scientific evidence that many MMPs, especially MMP-2, play important roles in the development of cardiovascular diseases; inhibition of these enzymes is beneficial to many cardiovascular conditions, sometimes precluding or postponing end-organ damage and fatal outcomes. Conducting comprehensive discussions and further studies on how MMPs participate in cardiovascular diseases is important, because inhibition of these enzymes may be an alternative or an adjuvant for current cardiovascular disease therapy.

Study of the correlations among some parameters of the oxidative status, gelatinases, and their inhibitors in a group of subjects with metabolic syndrome

Our aim was to examine some parameters of oxidative status, gelatinases, and their inhibitors and to evaluate their interrelationships in subjects with metabolic syndrome (MS). We enrolled 65 MS subjects, subdivided according to the presence or not of diabetes mellitus. We examined lipid peroxidation (expressed as thiobarbituric acid reacting substances, TBARS), protein oxidation (expressed as carbonyl groups), nitric oxide metabolites (NO_x), total antioxidant status (TAS), MMP-2, MMP-9, TIMP-1, and TIMP-2. We found that MS subjects, diabetics and nondiabetics, showed an increase in TBARS, PC, and NO_x. A significant decrease in TAS was observed only in nondiabetic MS subjects in comparison with diabetic MS subjects. We observed increased concentrations of MMP-2, MMP-9, TIMP-1, and TIMP-2, higher in diabetic subjects. Our data showed a positive correlation between TAS and MMP-2, TAS and MMP-9, and TAS and MMP-9/TIMP-1 and a negative correlation between TBARS and MMP-2 in diabetic MS subjects in the entire group. In MS subjects a prooxidant status and increased levels of gelatinases and their inhibitors are evident although the correlations between oxidative stress and MMPs or TIMPs are controversial and need further investigation.

Is isolated systolic hypertension worse than combined systolic/diastolic hypertension?

New developments in cardiovascular translational sciences have significantly advanced our understanding of the endovascular biology of blood pressure. Reductions in vascular elasticity and vessel compliance of conduit arteries are key components of both ISH and SDH. Vascular changes from the matrix metalloproteinase family of enzymes are involved in arterial wall remodeling and vascular stiffness. This new translational information helps further our understanding of both ISH and SDH.