Matrix metalloproteinases in peripheral vascular disease

High salt intake and HIV infection on endothelial glycocalyx shedding in salt-sensitive hypertension

The endothelial glycocalyx is closely associated with various physiological and pathophysiological events. Significant modification of the endothelial glycocalyx is an early process in the pathogenesis of cardiovascular disease. High dietary salt and HIV infection damages the endothelial glycocalyx causing endothelial dysfunction and increasing the risk for salt-sensitive hypertension and cardiovascular disease. The two factors, HIV infection and dietary salt are critical independent predictors of hypertension and cardiovascular disease and often synergize to exacerbate and accelerate disease pathogenesis. Salt-sensitive hypertension is more common among people living with HIV and is associated with risk for cardiovascular disease, stroke, heart attack and even death. However, the underlying mechanisms linking endothelial glycocalyx damage to dietary salt and HIV infection are lacking. Yet, both HIV infection/treatment and dietary salt are closely linked to endothelial glycocalyx damage and development of salt-sensitive hypertension. Moreover, the majority of individuals globally, consume more salt than is recommended and the burden of HIV especially in sub-Sahara Africa is disproportionately high. In this review, we have discussed the missing link between high salt and endothelial glycocalyx shedding in the pathogenesis of salt-sensitive hypertension. We have further elaborated the role played by HIV infection and treatment in modifying endothelial glycocalyx integrity to contribute to the development of hypertension and cardiovascular disease.

Neutrophil Elastase Inhibition by Sivelestat (ONO-5046) Attenuates AngII-Induced Abdominal Aortic Aneurysms in Apolipoprotein E-Deficient Mice

BACKGROUND

Abdominal aortic aneurysm (AAA) is an arterial disease characterized by dilatation of the aortic wall. It has been suggested that neutrophil counts and neutrophil elastase activity are associated with AAA. We investigated whether a neutrophil elastase (NE) inhibitor, sivelestat (Siv), had a protective effect against angiotensin II (AngII)-induced AAAs.

METHODS

Male apolipoprotein E-deficient mice were assigned into three groups: Vehicle + saline, AngII + saline, and AngII + Siv. All mice were administered intraperitoneally with either Siv or vehicle twice daily after AngII infusion.

RESULTS

In the 4-week AngII infusion study, plasma NE concentration (P = 0.041) and its activity (P = 0.011) were elevated by AngII. These increases were attenuated by Siv (concentration:P = 0.010, activity:P = 0.027). Further, plasma elastase activity was closely correlated with aortic width (R = 0.6976, P < 0.001). In the 1-week AngII infusion study, plasma and tissue elastase activity increased by AngII (plasma:P = 0.034, tissue:P < 0.001), but were reduced by Siv (plasma:P = 0.014, tissue:P = 0.024). AngII increased aortic width (P = 0.011) but was attenuated by co-administration of Siv (P = 0.022). Moreover, Siv decreased the incidence of AAAs (P = 0.009). Elastin fragmentation induced by AngII was reduced by Siv. Many inflammatory cells that were either CD68 or Gr-1 positive were observed in the AngII + saline group, whereas few inflammatory cells were accumulated in the AngII + Siv group. MMP-2 and MMP-9 were enhanced by AngII, but were reduced by Siv. In vitro, MMP-2 activity was induced by human NE (medium:P < 0.001, cells:P = 0.001), which was attenuated by co-incubation of Siv in medium (P < 0.001) and protein of human aortic smooth muscle cells (P = 0.001).

CONCLUSIONS

Siv attenuated AngII-induced AAA through the inhibition of NE.

Serum Brevican as a Biomarker of Cerebrovascular Disease in an Elderly Cognitively Impaired Cohort

In the brain, the extracellular matrix (ECM) composition shapes the neuronal microenvironment and can undergo substantial changes with cerebral pathology. Brevican is integral to the formation of the ECM's neuroprotective perineuronal nets (PNNs). Decreased brevican levels were reported in vascular dementia (VaD) but not in Alzheimer's disease (AD). However, the status of brevican in clinical cohorts with high concomitance of AD pathological burden and cerebrovascular disease (CeVD) is unclear. In this study, 32 non-cognitively impaired (NCI), 97 cognitively impaired no dementia (CIND), 46 AD, and 23 VaD participants recruited from memory clinics based in Singapore underwent neuropsychological and neuroimaging assessments, together with measurements of serum brevican. Association analyses were performed between serum brevican and neuroimaging measures of CeVDs, including white matter hyperintensities (WMHs), lacunes, cortical infarcts, and cerebral microbleeds. Using an aggregated score for CeVD burden, only CIND participants showed lower brevican levels with higher CeVD compared to those with lower CeVD burden (p = 0.006). Among the CeVD subtypes assessed, only elevated WMH burden was associated with lower brevican levels (OR = 2.7; 95% CI = 1.3-5.5). Our findings suggest that brevican deficits may play a role in early cerebrovascular damage in participants at risk of developing dementia.

Toll-like receptor 4 deficiency in mice impairs venous thrombus resolution

Objective: Toll-like receptor 4 (TLR4) is crucial to the development of sterile inflammatory responses. The deep venous thrombosis resolution (DVT) is similar to sterile inflammation, so we hypothesize that TLR4 is involved. Methods and Results: We evaluated the effects of TLR4 deficiency on thrombus lysis in vivo, and explored the mechanisms in vitro. DVT mouse model was established by inferior vena cava (IVC) ligation. After the IVC ligation (1, 3, and 7 d), the mice were euthanized to collect the venous thrombus. The Tlr4-/- mice had significantly elevated weight/length ratios of thrombi at 3 and 7 d and increased collagen content at 3 d after IVC ligation, in addition to significantly lesser intrathrombus infiltration of neutrophils and macrophages, lower monocyte chemoattractant protein-1 (MCP-1) and matrix metalloproteinase-9 (MMP-9) expression in thrombus tissue sections and homogenates, and lower pro-MMP-9 activity at 3 d after IVC ligation than wild-type mice. After 7 days of IVC ligation, VEGF, IFNβ, and MCP-5 protein expression were decreased in venous thrombus from Tlr4-/- mice. 2 ml of 3% thioglycolate was injected intraperitoneally and peritoneal exudate was collected 3 days later from Tlr4-/- and wild type mice respectively. The intraperitoneal macrophages were isolated from adherent culture after centrifugation. Lipopolysaccharide (LPS) can activate TLR4/NF-κB signalling pathway in a concentration-dependent manner, initiated p65 nuclear translocation, IκBα phosphorylation and degradation, MMP-9 and MCP-1 transcription in WT intraperitoneal macrophages but not in Tlr4-/- intraperitoneal macrophages. Conclusion: TLR4 is involved in venous thrombosis resolution through NF-κB pathway. Loss of TLR4 in mice impairs the process.

Outlook on Chronic Venous Disease Treatment: Phytochemical Screening, In Vitro Antioxidant Activity and In Silico Studies for Three Vegetal Extracts

Chronic venous disease is one of the most common vascular diseases; the signs and symptoms are varied and are often neglected in the early stages. Vascular damage is based on proinflammatory, prothrombotic, prooxidant activity and increased expression of several matrix metalloproteinases (MMPs). The aim of this research is preparation and preliminary characterization of three vegetal extracts (Sophorae flos-SE, Ginkgo bilobae folium-GE and Calendulae flos-CE). The obtained dry extracts were subjected to phytochemical screening (FT-ICR-MS, UHPLC-HRMS/MS) and quantitative analysis (UHPLC-HRMS/MS, spectrophotometric methods). Antioxidant activity was evaluated using three methods: FRAP, DPPH and ABTS. More than 30 compounds were found in each extract. The amount of flavones follows the succession: SE > GE > CE; the amount of phenolcarboxylic acids follows: SE > CE > GE; and the amount of polyphenols follows: SE > GE > CE. Results for FRAP method varied as follows: SE > CE > GE; results for the DPPH method followed: SE > GE > CE; and results for ABTS followed: SE > GE > CE. Strong and very strong correlations (appreciated by Pearson coefficient) have been observed between antioxidant activity and the chemical content of extracts. Molecular docking studies revealed the potential of several identified phytochemicals to inhibit the activity of four MMP isoforms. In conclusion, these three extracts have potential in the treatment of chronic venous disease, based on their phytochemical composition.

Initial research on the effect and mechanism of Tivozanib on pulsed dye laser induced angiogenesis

INTRODUCTION

Pulsed dye laser (PDL) is the main treatment for port wine stain (PWS), but a considerable number of patients show low clearances. The reason for the poor efficacy is related to PDL-induced angiogenesis. Vascular endothelial growth factor (VEGF) plays an important role in PDL-induced angiogenesis and can activate the tyrosine kinase activity of VEGF receptor (VEGFR) in endothelial cells. It triggers a full range of responses, and then participates in the regulation of angiogenesis. Tivozanib is an inhibitor of VEGFR tyrosine kinase activity, which can block the pro-angiogenic effect of VEGF and reduce vascular permeability.

METHOD

Different energy densities of PDL were used to irradiate the abdominal skin of rats. According to the general and pathological changes of the irradiated area, the energy density of 8 J/cm² with smaller scab and stronger vascular effect was selected for follow-up experiments. Divided the rat abdomen skin into four areas, irradiated three of them uniformly with an energy density of 8 J/cm² , and applied different concentrations of Tivozanib coating agent to the laser irradiation area, and grouped them as follows: (1) vacant group, (2) control group, (3) 0.5% Tivozanib group, (4) 1% Tivozanib group. Camera and dermoscopy were used to observe skin changes. Hematoxylin-eosin staining, immunohistochemical staining, and blood vessels were counted to detect dermal vascular regeneration. Transcriptome sequencing and real-time polymerase chain reaction (PCR) were conducted to elucidate the mechanism and validate the reliability.

RESULTS

The number of blood vessels in the 0.5% Tivozanib group and 1% Tivozanib group was significantly reduced on the 7, 10, and 14 days compared with the control group. The number of blood vessels in the 1% Tivozanib group was significantly reduced compared with the 0.5% Tivozanib group, indicating that Tivozanib successfully inhibited PDL-induced angiogenesis, and the inhibitory effect of 1% Tivozanib was more significant than that of 0.5% Tivozanib. Transcriptome sequencing results showed a total of 588 significantly differentially expressed genes, including 90 upregulated genes and 498 downregulated genes. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that the significantly differentially expressed genes were mainly enriched in the metabolic pathways which were closely related to angiogenesis. Finally, real-time PCR was used to verify the genes with higher expression differences, the top ranking and closely related to angiogenesis, namely, Cxcl1, Cxcl2, Cxcl3, Cxcl6, Ccl3, Csf3, IL1β, iNOS, Mmp9, Mmp13, Plau, Ets1, Spp1, Nr4a1. The results were consistent with the trend of transcriptome sequencing results, which proved the reliability of this study.

CONCLUSION

This study explored the inhibitory effect of Tivozanib on PDL-induced angiogenesis, and provided a new idea for the treatment of clinical PWS. Transcriptome sequencing explored the mechanism and provided reliable clues for later in-depth research.

Artificial Intelligence Uncovers Natural MMP Inhibitor Crocin as a Potential Treatment of Thoracic Aortic Aneurysm and Dissection

Thoracic aortic aneurysm and dissection (TAAD) is a lethal cardiovascular condition without effective pharmaceutical therapy. Identifying novel drugs that target the key pathogenetic components is an urgent need. Bioinformatics analysis of pathological studies indicated “extracellular matrix organization” as the most significant functional pathway related to TAAD, in which matrix metallopeptidase (MMP) 2 and MMP9 ranked above other proteases. MMP1-14 were designated as the prototype molecules for docking against PubChem Compound Database using Surflex-Dock, and nine natural compounds were identified. Using a generic MMP activity assay and an aminopropionitrile (BAPN)-induced TAAD mouse model, we identified crocin as an effective MMP inhibitor, suppressing the occurrence and rupture of TAAD. Biolayer interferometry and AI/bioinformatics analyses indicated that crocin may inhibit MMP2 activity by direct binding. Possible binding sites were investigated. Overall, the integration of artificial intelligence and functional experiments identified crocin as an MMP inhibitor with strong therapeutic potential.

A Multiscale Approach for Predicting Certain Effects of Hand-Transmitted Vibration on Finger Arteries

Prolonged exposure to strong hand-arm vibrations can lead to vascular disorders such as Vibration White Finger (VWF). We modeled the onset of this peripheral vascular disease in two steps. The first consists in assessing the reduction in shearing forces exerted by the blood on the walls of the arteries (Wall Shear Stress—WSS) during exposure to vibrations. An acute but repeated reduction in WSS can lead to arterial stenosis characteristic of VWF. The second step is devoted to using a numerical mechano-biological model to predict this stenosis as a function of WSS. WSS is reduced by a factor of 3 during exposure to vibration of 40 m·s−2. This reduction is independent of the frequency of excitation between 31 Hz and 400 Hz. WSS decreases logarithmically when the amplitude of the vibration increases. The mechano-biological model simulated arterial stenosis of 30% for an employee exposed for 4 h a day for 10 years. This model also highlighted the chronic accumulation of matrix metalloproteinase 2. By considering daily exposure and the vibratory level, we can calculate the degree of stenosis, thus that of the disease for chronic exposure to vibrations.

Collateral Arteriogenesis Involves a Sympathetic Denervation That Is Associated With Abnormal α-Adrenergic Signaling and a Transient Loss of Vascular Tone

Stimulating collateral arteriogenesis is an attractive therapeutic target for peripheral artery disease (PAD). However, the potency of arteriogenesis-stimulation in animal models has not been matched with efficacy in clinical trials. This may be because the presence of enlarged collaterals is not sufficient to relieve symptoms of PAD, suggesting that collateral function is also important. Specifically, collaterals are the primary site of vascular resistance following arterial occlusion, and impaired collateral vasodilation could impact downstream tissue perfusion and limb function. Therefore, we evaluated the effects of arteriogenesis on collateral vascular reactivity. Following femoral artery ligation in the mouse hindlimb, collateral functional vasodilation was impaired at day 7 (17 ± 3 vs. 60 ± 8%) but restored by day 28. This impairment was due to a high resting diameter (73 ± 4 μm at rest vs. 84 ± 3 μm dilated), which does not appear to be a beneficial effect of arteriogenesis because increasing tissue metabolic demand through voluntary exercise decreased resting diameter and restored vascular reactivity at day 7. The high diameter in sedentary animals was not due to sustained NO-dependent vasodilation or defective myogenic constriction, as there were no differences between the enlarged and native collaterals in response to eNOS inhibition with L-NAME or L-type calcium channel inhibition with nifedipine, respectively. Surprisingly, in the context of reduced vascular tone, vasoconstriction in response to the α-adrenergic agonist norepinephrine was enhanced in the enlarged collateral (−62 ± 2 vs. −37 ± 2%) while vasodilation in response to the α-adrenergic antagonist prazosin was reduced (6 ± 4% vs. 22 ± 16%), indicating a lack of α-adrenergic receptor activation by endogenous norepinephrine and suggesting a denervation of the neuroeffector junction. Staining for tyrosine hydroxylase demonstrated sympathetic denervation, with neurons occupying less area and located further from the enlarged collateral at day 7. Inversely, MMP2 presence surrounding the enlarged collateral was greater at day 7, suggesting that denervation may be related to extracellular matrix degradation during arteriogenesis. Further investigation on vascular wall maturation and the functionality of enlarged collaterals holds promise for identifying novel therapeutic targets to enhance arteriogenesis in patients with PAD.

Protective effect of liquiritin on coronary heart disease through regulating the proliferation of human vascular smooth muscle cells via upregulation of sirtuin1

This study aimed to explore whether liquiritin affects the development of coronary heart disease by regulating the proliferation and migration of human vascular smooth muscle cells (hVSMCs). A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 H-tetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) release detection were performed to measure the toxic effects of liquiritin on hVSMCs. An in vitro atherosclerosis model in hVSMCs was established using oxidized low-density lipoprotein (ox-LDL), and cell proliferation and apoptosis were detected using an MTT assay and flow cytometry analysis. Western blotting and reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) were used to detect protein and mRNA expressions, respectively. Caspase3 activity and cell migration were measured using an activity detection kit and Transwell assay, respectively. The results indicated that liquiritin at doses <160 μM had no significant effect on cell viability and LDH release in hVSMCs. Ox-LDL significantly induced cell proliferation and migration, and inhibited hVSMCs apoptosis. Liquiritin significantly inhibited cell proliferation and migration, and enhanced cell apoptosis in ox-LDL induced hVSMCs. Sirtuin1 (SIRT1) was lowly expressed in atherosclerotic plaque tissues in coronary heart disease patients and in ox-LDL-induced hVSMCs. Liquiritin improved SIRT1 expression in ox-LDL-induced hVSMCs, whereas the improvement was inhibited by Selisistat (EX 527, an effective SIRT1 inhibitor) treatment. EX 527 reversed the effects of liquiritin on cell proliferation, migration, and apoptosis in ox-LDL-induced hVSMCs In conclusion, liquiritin plays a protective role in coronary heart disease by regulating the proliferation and migration of hVSMCs by increasing SIRT1 expression.

Heparanase as active player in endothelial glycocalyx remodeling

The surface of all animal cells is coated with a layer of carbohydrates linked in various ways to the outer side of the plasma membrane. These carbohydrates are mainly bound to proteins in the form of glycoproteins and proteoglycans and together with the glycolipids constitute the so-called glycocalyx. In particular, the endothelial glycocalyx that covers the luminal layer of the endothelium is composed of glycosaminoglycans (heparan sulphate -HS and hyaluronic acid -HA), proteoglycans (syndecans and glypicans) and adsorbed plasma proteins. Thanks to its ability to absorb water, this structure contributes to making the surface of the vessels slippery but at the same time acts by modulating the mechano-transduction of the vessels, the vascular permeability and the adhesion of leukocytes in thus regulating several physiological and pathological events. Among the various enzymes involved in the degradation of the glycocalyx, heparanase (HPSE) has been shown to be particularly involved. This enzyme is responsible for the cutting of heparan sulfate (HS) chains at the level of the proteoglycans of the endothelial glycocalyx whose dysfunction appears to have a role in organ fibrosis, sepsis and viral infection. In this mini-review, we describe the mechanisms by which HPSE contributes to glycocalyx remodeling and then examine the role of glycocalyx degradation in the development of pathological conditions and pharmacological strategies to preserve glycocalyx during disease pathogenesis.

Endothelial Glycocalyx as a Regulator of Fibrotic Processes

The endothelial glycocalyx, the gel layer covering the endothelium, is composed of glycosaminoglycans, proteoglycans, and adsorbed plasma proteins. This structure modulates vessels’ mechanotransduction, vascular permeability, and leukocyte adhesion. Thus, it regulates several physiological and pathological events. In the present review, we described the mechanisms that disturb glycocalyx stability such as reactive oxygen species, matrix metalloproteinases, and heparanase. We then focused our attention on the role of glycocalyx degradation in the induction of profibrotic events and on the possible pharmacological strategies to preserve this delicate structure.

Deep vein thrombosis inhibitor may play a therapeutic role in post-stroke patients

BACKGROUND

Deep vein thrombosis (DVT) is associated with stroke. Here, we hypothesize that genes associated with DVT may also play roles in the development of stroke.

METHODS

we firstly conducted large-scale literature based disease-gene relationship data analysis to explore the genes implicated with DVT and stroke. Further, a mega-analysis was conducted for each of these genes that were linked to DVT but not stroke, using 11 independent stroke RNA expression datasets (176 stroke cases and 102 healthy controls). Then, a multiple linear regression (MLR) model was employed to study possible influential factors on the gene expression levels in stroke. After that, a functional pathway analysis was performed to identify the potential biological linkage between stroke and the target genes suggested by mega-analysis.

RESULTS

Over 81.10% genes implicated with DVT also suggested an association with stroke. Among the 24 DVT-specific genes, one DVT-inhibiting gene, SP1, presented significantly increased expression in stroke (LFC = 1.34, p-value = 0.0045). Pathway analysis showed that SP1 may play a therapeutic role in post-stroke patients by promoting multiple of stroke-inhibitors. Moreover, geographical region was indicated as an influential factor on the expression levels of SP1 in stroke samples (p-value = 0.037).

CONCLUSION

Our results suggested that DVT inhibitor SP1 could be a novel therapeutic target gene for post-stroke treatment. Further study of the potential relations between SP1 and stroke was guaranteed.

S-glutathionylation, friend or foe in cardiovascular health and disease

Glutathione is a low molecular weight thiol that is present at high levels in the cell. The high levels of glutathione in the cell make it one of the most abundant antioxidants contributing to cellular redox homeostasis. As a general rule, throughout cardiovascular disease and progression there is an imbalance in redox homeostasis characterized by reactive oxygen species overproduction and glutathione underproduction. As research into these imbalances continues, glutathione concentrations are increasingly being observed to drive various physiological and pathological signaling responses. Interestingly in addition to acting directly as an antioxidant, glutathione is capable of post translational modifications (S-glutathionylation) of proteins through both chemical interactions and enzyme mediated events. This review will discuss both the chemical and enzyme-based S-glutathionylation of proteins involved in cardiovascular pathologies and angiogenesis.

Involvement of Matrix Metalloproteinase 9 in Vertebral Arterial Dissection With Posterior Circulation Ischemic Stroke

Background

Spontaneous vertebral arterial dissection (VAD) is an important cause of posterior circulation ischemic stroke (PCS), but its pathogenesis remains elusive. Matrix metalloproteinase 9 (MMP‐9) is a gelatinase involved in inflammation process and several vascular diseases, such as aorta dissection, but its role in VBD is unclear yet. The present study aimed to determine the association between serum MMP‐9 level and VAD‐related PCS.

Methods and Results

We recruited 149 patients with PCS, of which 30 were VAD and 119 had other determined etiologies (non‐VAD), and 219 non‐stroke individuals. Serum MMP‐9 was measured within 14 days from stroke onset. The age of VAD group was 59.6±15.0 years, which is similar to non‐stroke group (P=0.510) but significantly younger than non‐VAD group (69.9±14.0 years, P<0.001). Males and vascular risk factors were significantly more prevalent in VAD and non‐VAD groups than non‐stroke group (P<0.001). Multivariate logistic regression analysis adjusting potential confounders revealed that every 100 ng/mL of serum MMP‐9 level increment significantly predicted VAD (versus non‐stroke group: odds ratio (OR), 4.572; 95% CI, 2.240–9.333, P<0.001; versus non‐VAD group: OR, 1.819; 95% CI, 1.034–3.200, P=0.038).

Conclusions

Patients with VAD‐related PCS had higher levels of serum MMP‐9 at the acute stage of stroke compared with non‐stroke individuals and PCS of other causes, supporting the potential involvement of extracellular matrix‐degrading protease in the mechanism of VAD, which leads to ischemic events.

Effect of microRNA-133a-3p/matrix metalloproteinase-9 axis on the growth of atherosclerotic vascular smooth muscle cells

Atherosclerosis (AS) is the leading cause of cardiovascular disease and poses a threat to human health. MicroRNAs (miRNAs/miRs) are a group of endogenous small non-coding RNAs that have been identified to serve important roles in AS. However, the expression and role of miR-133a-3p in AS remains unclear. The aim of the present study was to investigate miR-133a-3p in AS and to determine its underlying mechanism. The level of miR-133a-3p expression in the blood and vascular plaque tissue of patients with AS was detected via reverse transcription-quantitative PCR (RT-qPCR). The role of miR-133a-3p in human vascular smooth muscle cells (hVSMCs) was investigated, following upregulation and downregulation of this miR in hVSMCs. Cell proliferation and apoptosis were determined using a Cell Counting kit-8 assay and flow cytometry, respectively. The results demonstrated the downregulation of miR-133a-3p in the blood and vascular plaque tissue of patients with AS. Matrix metallopeptidase-9 (MMP-9) was revealed to be a direct target gene of miR-133a-3p, which was upregulated in the blood and vascular plaque tissue of patients with AS. Furthermore, MMP-9 was determined to be negatively regulated by miR-133a-3p in hVSMCs. In addition, significant inhibition of hVSMC proliferation and induction of cell apoptosis were observed following MMP-9 downregulation and following transfection with the miR-133a-3p mimic. The effects of the miR-133a-3p mimic on hVSMC proliferation and apoptosis were reversed by MMP-9 over-expression. Overall, the results indicated that miR-133a-3p was downregulated in AS, which results in the inhibition of hVSMC proliferation and the induction of cell apoptosis via MMP-9. miR-133a-3p may therefore be a promising therapeutic target for the treatment of AS.

Matrix Metalloproteinases in Renal Diseases: A Critical Appraisal

Matrix metalloproteinases (MMPs) are endopeptidases within the metzincin protein family that not only cleave extracellular matrix (ECM) components, but also process the non-ECM molecules, including various growth factors and their binding proteins. MMPs participate in cell to ECM interactions, and MMPs are known to be involved in cell proliferation mechanisms and most probably apoptosis. These proteinases are grouped into six classes: collagenases, gelatinases, stromelysins, matrilysins, membrane type MMPs, and other MMPs. Various mechanisms regulate the activity of MMPs, inhibition by tissue inhibitors of metalloproteinases being the most important. In the kidney, intrinsic glomerular cells and tubular epithelial cells synthesize several MMPs. The measurement of circulating MMPs can provide valuable information in patients with kidney diseases. They play an important role in many renal diseases, both acute and chronic. This review attempts to summarize the current knowledge of MMPs in the kidney and discusses recent data from patient and animal studies with reference to specific diseases. A better understanding of the MMPs' role in renal remodeling may open the way to new interventions favoring deleterious renal changes in a number of kidney diseases.

Atherosclerosis Treatment with Stimuli-Responsive Nanoagents: Recent Advances and Future Perspectives

Atherosclerosis is the root of approximately one-third of global mortalities. Nanotechnology exhibits splendid prospects to combat atherosclerosis at the molecular level by engineering smart nanoagents with versatile functionalizations. Significant advances in nanoengineering enable nanoagents to autonomously navigate in the bloodstream, escape from biological barriers, and assemble with their nanocohort at the targeted lesion. The assembly of nanoagents with endogenous and exogenous stimuli breaks down their shells, facilitates intracellular delivery, releases their cargo to kill the corrupt cells, and gives imaging reports. All these improvements pave the way toward personalized medicine for atherosclerosis. This review systematically summarizes the recent advances in stimuli-responsive nanoagents for atherosclerosis management and its progress in clinical trials.

MMP targeting in the battle for vision: Recent developments and future prospects in the treatment of diabetic retinopathy

Matrix metalloproteinases (MMPs) are enzymes capable of degrading nearly all types of extracellular matrix. They perform a wide range of roles in physiological processes, which is the reason for their strict regulation by numerous mechanisms including natural tissue inhibitors of metalloproteinases (TIMP). Research only started to shed light on more troublesome aspects of MMPs function, like cancer progression, Alzheimer's disease, atherosclerosis, ageing. Moreover, their profound role in diabetes is being carefully investigated including one of its most debilitating complications - diabetic retinopathy (DR), the leading cause of acquired blindness worldwide. Traditional treatment of this condition seems to be only mildly satisfactory, which elicited substantial interest in the field of new therapeutic methods including MMP targeting. So far, significant roles of MMP-2 and MMP-9 in the development of retinopathy have been established, with special attention given to the process of blood-retinal barrier impairment. Further exploration revealed MMP-10 and MMP-14 involvement as well as changes in MMP/TIMP ratio. In this review, we provide insight into MMPs role in diabetic retinopathy with a clarification of various mechanisms regulating MMP activity in the light of the recent studies. We conclude with an overview of novel DR therapies targeting MMPs and point to the need of further examination of their usefulness in clinical setting, with an eye towards future research.

Cardiovascular organ damage in type 2 diabetes mellitus: the role of lipids and inflammation

BACKGROUND

The relationship between dyslipidemia, inflammation and CV organ damage in type 2 diabetes mellitus (T2DM) is complex. Insulin resistance and inflammatory cytokines interleukins (ILs) increase plasma triglycerides (TG). ILs also up-regulate expression of matrix-metalloproteinases (MMPs) that, together with TG, decrease high density lipoprotein cholesterol (HDL) levels. High TG, low HDL, increased ILs and MMPs trigger structural and functional changes in different parts of cardiovascular (CV) system. To understand better the role of lipids and inflammation in CV organ damage, the present study investigated the inter-relationships between lipids, ILs and MMPs, as well as the associations of lipids, ILs and MMPs with various CV measures, both in diabetic and non-diabetic population (nonT2DM).

METHODS

In T2DM patients (N = 191) and nonT2DM subjects (N = 94) were assessed carotid intima-media thickness (cIMT) and inter-adventitial diameter (IADiam), carotid wave speed (ccaWS), carotid-femoral pulse wave velocity (cfPWV), left ventricular (LV) mass, LV systolic (s') and early diastolic (e') longitudinal velocities of mitral annulus, together with glycemic control, lipid profile, IL-6, IL-18 and MMP-12.

RESULTS

T2DM patients, as compared to nonT2DM subjects, had significantly higher plasma levels of IL-6, IL-18, MMP-12 and lower HDL (P < 0.05-0.0001). They had also higher cIMT, IADiam, ccaWS, cfPWV and LV mass, and lower e' velocity (P < 0.005-0.0001). Both in T2DM patients and nonT2DM subjects, MMP-12 increased with IL-6 (r = 0.43 and 0.39; P < 0.0001) and IL-18 (r = 0.32 and 0.42; P < 0.0001), and HDL decreased with MMP-12 (r = - 0.29 and - 0.42; P < 0.0001). In both populations, MMP-12 was directly associated with IADiam, ccaWS, cfPWV and LV mass (r = 0.42, 0.32, 0.26 and 0.29; P < 0.0001 in T2DM patients, and r = 0.39, 0.28, 0.32 and 0.27; P < 0.01-0.0001 in nonT2DM subjects). In multivariate analysis, MMP-12 remained independently related to IADiam, ccaWS, cfPWV and LV mass in T2DM patients, and to IADiam only in nonT2DM subjects.

CONCLUSIONS

This cross-sectional study demonstrated a direct association between ILs and MMP-12, as well as an inverse association between MMP-12 and HDL, both in T2DM patients and in nonT2DM subjects. In T2DM patients, who had higher levels of ILs and MMP-12, the latter was independently related to several structural and functional markers of preclinical CV organ damage.

MicroRNA-133b regulates the growth and migration of vascular smooth muscle cells by targeting matrix metallopeptidase 9

Atherosclerosis is a systemic disease affecting the whole arterial tree of the human body, and it is the leading cause of cardiovascular diseases.Vascular smooth muscle cells (VSMCs) have been identified to play a key role in the development of atherosclerosis. MicroRNAs (miRNAs) are a group of endogenous small non-coding RNAs, and they play a critical role in many biological processes including regulating cell proliferation, migration and apoptosis. However, till now, the expression and role of miR-133b in atherosclerosis remain largely unknown. Therefore, our purpose was to investigate the expression and role of miR-133b in atherosclerosis and to explore the underlying mechanism. The results showed that miR-133b was down-regulated in the blood and vascular plaque tissues of rabbits with atherosclerosis. Matrix metallopeptidase 9 (MMP-9) was a direct target of miR-133b. In addition, our data indicated that miR-133b mimic could significantly inhibit rVSMC cell proliferation activity, migration ability and induce cell apoptosis compared with the control group, and all these effects were reversed by MMP-9-plasmid. Taken together, these findings highlight an important role for miR-133b/MMP-9 axis in atherosclerosis. And miR-133b might be a valuable clinical marker and therapeutic target for atherosclerosis.

The effect of resveratrol on expression of matrix metalloproteinase 9 and its tissue inhibitors in vascular smooth muscle cells

BACKGROUND

Matrix metalloproteinase 9 (MMP-9) is involved in extracellular matrix degradation and remodeling. An increase in MMP-9 expression by vascular component cells plays an important role in atherosclerotic plaque formation and rupture. Resveratrol, a polyphenolic substance, was suggested to play a role in preventing the progress of atherosclerotic disease. The aim of this study was to investigate the effect of resveratrol on MMP-9 and tissue inhibitors of metalloproteinases (TIMPs) in vascular smooth muscle cells (VSMCs) after treatment with H2O2.

METHODS

Cultured VSMCs were pre-treated with 0.2 mM of H2O2 before stimulation with different concentration of resveratrol. Expression of MMP-9, TIMP-1, and TIMP-3 genes were measured using real-time polymerase chain reaction (PCR) method, and MMP-9 protein level was detected using western blot analysis.

RESULTS

Resveratrol at 120 μmol/l concentration reduced the elevated level of MMP-9 induced by H2O2 in VSMCs as 1.85 ± 0.35 folds (P < 0.050) and 8.70 ± 1.20 folds (P < 0.050) after 24 and 48 hours, respectively. Resveratrol increased the diminished level of TIMP-1 induced by H2O2 as 2.5 ± 0.48 folds following the treatment with 120 μmol/l after 48 hours (P < 0.050).

CONCLUSION

Resveratrol as an antioxidant can decrease MMP-9 production, not only by suppressing MMP-9 expression, but also by augmenting TIMP-1 production. Altogether, resveratrol as an antioxidant can regulate the MMP-9/TIMP-1 balance, and may be considered as a preservative agent in the treatment and prevention of atherosclerosis.

Comparative Study of Protein Expression Levels of Five Plaque Biomarkers and Relation with Carotid Plaque Type Classification in Patients after Carotid Endarterectomy

Atherosclerosis is an inflammatory process resulting in local plaque deposition in the vessel wall of arteries with symptoms to various areas of vascular tree. Identification of patients with progressive advanced atherosclerotic disease is mainly based on the known characteristics of the vulnerable or recently ruptured plaque. Molecular and cellular features associated with the vulnerable plaque are considered potential diagnostic markers for plaque rupture and thrombosis. Here, protein expression levels of the metalloproteases MMP-1, MMP-9, osteopontin (OPN), and cytokines TNFα and IL-6 in tissue extracts of carotid plaques in patients after endarterectomy were estimated by Western immunoblotting, after SDS-PAGE analysis and evaluated based on the ultrasonographic plaque morphology. The gender and age effect was also examined. MMP-1, MMP-9, and IL-6 were expressed in higher levels compared to OPN and TNFa as well as in symptomatic (with type II and III carotid plaque classification) than asymptomatic (type IV) patients with differences considered statistically significant (P values <0.05). A significant positive correlation between MMP-1 and IL-6 (with Pearson correlation coefficient 0.748) is also notable. The data give further insight into the possible role of specific biomarker and enhance the need for further studies in order to clarify the proper one(s) for detection of the vulnerable plaque and help identify patients at risk for cardiovascular events.

Homocysteine-Enhanced Proteolytic and Fibrinolytic Processes in Thin Intraluminal Thrombus and Adjacent Wall of Abdominal Aortic Aneurysm: Study In Vitro

Homocysteine (Hcy) may affect the pathogenesis of abdominal aortic aneurysms (AAAs) through enhancement of proteolysis and an impaired coagulation/fibrinolysis system. Intensified haemostatic capacity may promote local proteolytic degradation of the aortic wall. This study aimed to examine the effects of Hcy on haemostatic and proteolytic processes in samples of thick and thin fragments of the ILT and underlying walls. Subjects and Methods. Thirty-six patients who underwent AAA surgery were enrolled. Aneurysm tissue sections were incubated with DL-Hcy (100 and 500 μmol/L) in a series of experiments and analyzed for concentration/activity of proteolytic and haemostatic markers by enzyme-linked immunosorbent assay. Results. Incubation of wall underlying thin ILT segments (B) with DL-Hcy resulted in an increase of active MMP-2 levels compared to control tissue (9.54 ± 5.88 versus 7.44 ± 4.48, p=0.011). DL-Hcy also induced t-PA and plasminogen concentration increases in thin thrombus sections (B1) compared to control tissue (respectively: 1.39 ± 1.65 versus 0.84 ± 0.74, p=0.024; 11.64 ± 5.05 versus 10.34 ± 5.52, p=0.018). In contrast, wall adjacent to thick thrombus segments (A) showed decreases in MMP-2 and TF activities compared to control (respectively, 5.89 ± 3.39 versus 7.26 ± 5.49, p=0.046; 67.13 ± 72.59 versus 114.46 ± 106.29, p=0.007). In thick ILT sections (A1), DL-Hcy decreased MMP-2 activity and t-PA and plasminogen concentrations compared to control tissue (respectively, 2.53 ± 2.02 versus 3.28 ± 2.65, p=0.006; 0.67 ± 0.57 versus 0.96 ± 0.91, p=0.021; 9.25 ± 4.59 versus 12.63 ± 9.56, p=0.017). In addition, analysis revealed positive correlations at all sites between activities/concentrations of MMP-2, TF, and PAI-1 measured in control tissues and after incubation with DL-Hcy. Conclusions. These data indicate the potential for excess Hcy to enhance damage of arterial wall in thinner AAA segments as a result of the increased activity of MMP-2 and fibrinolytic factors.

Multifunctional, JNK-inhibiting nanotherapeutics for augmented elastic matrix regenerative repair in aortic aneurysms

Growth of abdominal aortic aneurysms (AAA), localized aortal wall expansions, is driven by the disruption and subsequent loss of aortal wall elastic fibers by matrix metalloproteases (MMPs). Since elastic fibers do not naturally regenerate or repair, arresting/reversing AAA growth has not been possible. Previously, we showed utility of doxycycline (DOX), an MMP inhibitor drug, to stimulate elastic matrix neoassembly and crosslinking at low microgram per milliliter doses in addition to inhibiting MMPs. We currently show in aneurysmal smooth muscle cell (SMC) cultures that effects of exogenous DOX in this dose range are linked to its upregulation of transforming growth factor beta (TGF-β1) via its inhibition of the regulatory protein c-Jun-N-terminal kinase 2 (JNK 2). We have identified a DOX dose range that stimulates elastogenesis and crosslinking without adversely impacting cell viability. Using JNK 2 inhibition as a metric for pro-regenerative matrix effects of DOX, we further demonstrate that sustained, steady-state release of DOX at the useful dose, from poly(ethylene glycol)-poly(lactic glycolic acid) nanoparticles (NPs), provides pro-elastogenic and anti-proteolytic effects that could potentially be more pronounced than that of exogenous DOX. We attribute these outcomes to previously determined synergistic effects provided by cationic amphiphile groups functionalizing the polymer NP surface. Released DOX inhibited expression and phosphorylation of JNK to likely increase expression of TGF-β1, which is known to increase elastogenesis and lysyl oxidase-mediated crosslinking of elastic matrix. Our results suggest that JNK inhibition is a useful metric to assess pro-elastic matrix regenerative effects and point to the combinatorial regenerative benefits provided by DOX and cationic-functionalized NPs.

miR-92a regulates the expression levels of matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 3 via sirtuin 1 signaling in hydrogen peroxide-induced vascular smooth muscle cells

Vascular smooth muscle cells (VSMCs) exhibit a notably increased rate of migration, which is one of the most common pathological changes in atherosclerosis. Investigations into the role of micro (mi)RNAs in the regulation of VSMC migration are beginning to emerge and additional miRNAs involved in VSMC migration modulation require identification. In the current study, VSMCs were primarily cultured from rat thoracic aortas, transfected with miR‑92a mimics and induced by hydrogen peroxide (H2O2) for 24 h. Total mRNA and protein were collected for quantitative polymerase chain reaction and western blot analysis. In addition, the sirtuin 1 (SIRT1) gene was detected by luciferase reporter assay and VSMC migration was detected by Transwell migration assay. The current results demonstrated that reduced expression of miR‑92a and overexpression of SIRT1 at the mRNA level were observed in H2O2‑induced VSMCs. Furthermore, luciferase reporter assay demonstrated that the activity of the SIRT1 3'‑untranslated region was reduced by miR‑92a mimics. The upregulation of MMP9 and the downregulation of TIMP3 in H2O2‑induced VSMCs were observed to be reversed by miR‑92a mimics in addition to SIRT1 siRNA. Finally, Transwell migration assay revealed that miR‑92a overexpression and silencing SIRT1 mitigated VSMC migration following H2O2 treatment. The present study indicated that miR‑92a prevented the migration of H2O2‑induced VSMCs by repressing the expression of SIRT1, and also provided a novel therapy to protect against the phenotypic change of VSMCs in atherosclerosis.

The Profile of Circulating Matrix Metalloproteinases in Patients Undergoing Lower Limb Endovascular Interventions for Peripheral Arterial Disease

BACKGROUND

Matrix metalloproteinases (MMPs) play a significant role in the development and progression of atherosclerotic vascular disease. We aimed to document the profile of circulating MMPs in peripheral arterial disease (PAD) patients undergoing lower limb endovascular revascularization.

METHODS

A total of 46 patients (37 male; mean age 66 ± 11 years) undergoing elective lower limb percutaneous revascularization (angioplasty/stent) for symptomatic PAD were recruited from 2 vascular centers. Exclusion criteria were: acute limb ischemia, active infection and/or wet gangrene, liver disease, end-stage renal disease, and cancer. Patients having open revascularization or hybrid (open combined with endovascular) procedures were also excluded. Peripheral venous blood samples were taken on admission and 24 hrs after the procedure. Levels of MMP-2, MMP-3, MMP-7, and MMP-9 were measured along with tissue inhibitors of MMPs (TIMPs) 1 and 2.

RESULTS

Compared to baseline values, there was a significant elevation in serum MMP-3 (P = 0.014) and MMP-7 (P = 0.008) levels, whereas serum MMP-9 showed a nonsignificant trend to increase (P = 0.169). On the other hand, no significant alterations were found 24 hrs after angioplasty/stenting with regard to the MMP-2 level and TIMP-1 and 2 levels.

CONCLUSIONS

This study documented the periprocedural profile of circulating MMPs in patients undergoing angioplasty/stenting for PAD. The implications of increased MMP-3 and MMP-7 activity after peripheral endovascular interventions and their potential clinical relevance require further investigation.

Differences in extracellular matrix proteins between Friesian horses with aortic rupture, unaffected Friesians and Warmblood horses

BACKGROUND

Unlike in Warmblood horses, aortic rupture is quite common in Friesian horses, in which a hereditary trait is suspected. The aortic connective tissue in affected Friesians shows histological changes such as medial necrosis, elastic fibre fragmentation, mucoid material accumulation and fibrosis with aberrant collagen morphology. However, ultrastructural examination of the collagen fibres of the mid-thoracic aorta has been inconclusive in further elucidating the pathogenesis of the disease.

OBJECTIVES

To assess several extracellular matrix (ECM) components biochemically in order to explore a possible underlying breed-related systemic ECM defect in Friesians with aortic rupture.

STUDY DESIGN

Cadaver study.

METHODS

Tissues from affected Friesians (n = 18), unaffected Friesians (n = 10) and Warmblood horses (n = 30) were compared. Samples were taken from the thoracic aorta at the level of the rupture site, from two locations caudal to the rupture and from the deep digital flexor tendon. Total collagen content, post-translational modifications of collagen formation including lysine hydroxylation, and hydroxylysylpyridinoline (HP), lysylpyridinoline (LP) and pyrrole cross-links were analysed. Additionally, elastin cross-links, glycosaminoglycan content and matrix metalloproteinase (MMP) activity were assessed.

RESULTS

Significantly increased MMP activity and increased LP and HP cross-linking, lysine hydroxylation and elastin cross-linking were found at the site of rupture in affected Friesians. These changes may reflect processes involved in healing and aneurysm formation. Unaffected Friesians had less lysine hydroxylation and pyrrole cross-linking within the tendons compared with Warmblood horses. No differences in the matrix of the aorta were found between normal Warmbloods and Friesian horses.

MAIN LIMITATIONS

Small sample size.

CONCLUSIONS

The differences in collagen parameters in tendon tissue may reflect differences in connective tissue metabolism between Friesians and Warmblood horses.

Combination of rosuvastatin and probucol inhibits MMP-9 expression via upregulation of miR-497 in cultured HUVECs and apoE knockout mice

This study deciphered the molecular mechanisms of the inhibition of MMP-9 expression using rosuvastatin in cultured human umbilical vein endothelial cells (HUVECs) and apoE knockout mice and whether the combination of rosuvastatin and probucol enhanced this effect. The role that microRNA (miR)-497 plays in the regulation of MMP-9 expression was evaluated in cultured HUVECs and apoE knockout mice using quantitative real-time reverse transcription polymerase chain reaction and Western blotting. First, TNFα significantly increased mitogen-activated protein kinases/extracellular signal-regulated kinase (MAPK/ERK) signaling and MMP-9 levels, and the transfection of miR-497 prevented this increase. The converse results were obtained after miR-497 suppression. Second, the administration of rosuvastatin or the combination of two drugs decreased MAPK/ERK signaling and MMP-9 levels, and the suppression of miR-497 upregulated these levels. Third, the administration of rosuvastatin or the combination of two drugs increased miR-497 expression levels in the aortas of apoE knockout mice, but the levels of serum lipids and plaque areas decreased, which improved plaque components and decreased the MAPK/ERK signaling and MMP-9 levels. Finally, the combination of the two drugs was more effective than the use of rosuvastatin alone. Rosuvastatin inhibits MMP-9 expression by upregulating miR-497 in HUVECs and apoE knockout mice, and the combination of rosuvastatin and probucol enhances this effect.

Oxidized LDL-Exposed Human Macrophages Display Increased MMP-9 Expression and Secretion Mediated by Endoplasmic Reticulum Stress

Oxidatively modified low-density lipoproteins (oxLDL) alter the proper function of the endoplasmic reticulum (ER), inducing ER stress (ERS), which consequently activates inflammatory pathways in macrophages. Matrix metalloproteinase-9 (MMP-9) is the main protease acting on the degradation of the extracellular matrix and the ensuing destabilization of the atherosclerotic plaque. We aimed to investigate whether ERS induced by oxLDL or tunicamycin (TM) in human macrophages is associated with the stimulation of MMP-9 expression and secretion. The results showed that oxLDL induced in THP-1 macrophages: (i) increase of MMP-9 gene expression and its pro-form secretion, (ii) intracellular accumulation of 7-ketocholesterol, (iii) ERS activation (increased eIF2α phosphorylation, XBP1 and CHOP mRNA levels, and Grp78 protein expression), and (iv) oxidative stress (increased levels of reactive oxygen species and NADPH oxidase activity). Incubation of macrophages with ERS inducer, TM determined the secretion of both pro- and active-form of MMP-9 and oxidative stress. Treatment of oxLDL or TM-incubated cells with ERS inhibitor, sodium phenylbutyrate decreased MMP-9 gene expression, secretion, and activity. The inhibitor of NADPH oxidase, apocynin, decreased XBP-1 and CHOP mRNA levels, and MMP-9 gene expression and secretion in oxLDL-exposed cells. In conclusion, oxLDL stimulate MMP-9 expression and secretion in human macrophages by mechanisms involving ERS. J. Cell. Biochem. 118: 661-669, 2017. © 2016 Wiley Periodicals, Inc.

Personalized Proteomics: The Future of Precision Medicine

Medical diagnostics and treatment has advanced from a one size fits all science to treatment of the patient as a unique individual. Currently, this is limited solely to genetic analysis. However, epigenetic, transcriptional, proteomic, posttranslational modifications, metabolic, and environmental factors influence a patient’s response to disease and treatment. As more analytical and diagnostic techniques are incorporated into medical practice, the personalized medicine initiative transitions to precision medicine giving a holistic view of the patient’s condition. The high accuracy and sensitivity of mass spectrometric analysis of proteomes is well suited for the incorporation of proteomics into precision medicine. This review begins with an overview of the advance to precision medicine and the current state of the art in technology and instrumentation for mass spectrometry analysis. Thereafter, it focuses on the benefits and potential uses for personalized proteomic analysis in the diagnostic and treatment of individual patients. In conclusion, it calls for a synthesis between basic science and clinical researchers with practicing clinicians to design proteomic studies to generate meaningful and applicable translational medicine. As clinical proteomics is just beginning to come out of its infancy, this overview is provided for the new initiate.

Amelioration of salvianolic acid C on aortic structure in apolipoprotein E-deficient mice treated with angiotension II

AIMS

Aortic aneurysm is a disastrous vascular disease with high morbidity and mortality. Matrix metalloproteinases (MMPs), especially MMP-9, is implicated in the development of aortic aneurysm, but the effective MMP inhibitors are far from development. To develop new candidate compound for aortic aneurysm therapy, we evaluated the effects of salvianolic acid C (SalC) against the formation of aortic aneurysm.

MATERIALS AND METHODS

Aortic aneurysm was induced by implantation of angiotension II (AngII) minipump in apolipoprotein E-deficient (ApoE^-/-) mice. MMPs activity was evaluated by enzyme kinetic analysis in vitro and in-gel gelatin zymography in vivo. The formation of aortic aneurysm was confirmed based on aortic maximum diameter. Hematoxylin and eosin stain was used to evaluate aortic structure, picrosirius red stain was for collagen deposition, and orcein stain was for elastin fragmentation. Macrophage infiltration was detected by CD68 immunohistochemistry.

KEY FINDINGS

Firstly, SalC showed significant inhibition on the activity of MMP-2 and MMP-9. Aortic aneurysm was defined as >50% increase in maximum diameter of aorta, and the down-regulated tendency of 20mg/kg SalC against formation of aortic aneurysm was detected. Also, 22.2% rupture was detected in ApoE^-/- mice, while no rupture of aortic aneurysm was found with 20mg/kg SalC treatment. Then, SalC was detected to maintain the integrity of aortic structure and protect elastin against fragmentation. Finally, SalC considerably inhibited infiltration of macrophage in the injury site of aorta.

SIGNIFICANCE

SalC significantly ameliorated the progression of aortic aneurysm in ApoE^-/- mice, and held great potential for aortic aneurysm therapy.

Multidimensional Contribution of Matrix Metalloproteinases to Atherosclerotic Plaque Vulnerability: Multiple Mechanisms of Inhibition to Promote Stability

The prevalence of atherosclerotic disease continues to increase, and despite significant reductions in major cardiovascular events with current medical interventions, an additional therapeutic window exists. Atherosclerotic plaque growth is a complex integration of cholesterol penetration, inflammatory cell infiltration, vascular smooth muscle cell (VSMC) migration, and neovascular invasion. A family of matrix-degrading proteases, the matrix metalloproteinases (MMPs), contributes to all phases of vascular remodeling. The contribution of specific MMPs to endothelial cell integrity and VSMC migration in atherosclerotic lesion initiation and progression has been confirmed by the increased expression of these proteases in plasma and plaque specimens. Endogenous blockade of MMPs by the tissue inhibitors of metalloproteinases (TIMPs) may attenuate proteolysis in some regions, but the progression of matrix degeneration suggests that MMPs predominate in atherosclerotic plaque, precipitating vulnerability. Plaque neovascularization also contributes to instability and, coupling the known role of MMPs in angiogenesis to that of atherosclerotic plaque growth, interest in targeting MMPs to facilitate plaque stabilization continues to accumulate. This article aims to review the contributions of MMPs and TIMPs to atherosclerotic plaque expansion, neovascularization, and rupture vulnerability with an interest in promoting targeted therapies to improve plaque stabilization and decrease the risk of major cardiovascular events.

The Discovery of Novel Genomic, Transcriptomic, and Proteomic Biomarkers in Cardiovascular and Peripheral Vascular Disease: The State of the Art

Cardiovascular disease (CD) and peripheral vascular disease (PVD) are leading causes of mortality and morbidity in western countries and also responsible of a huge burden in terms of disability, functional decline, and healthcare costs. Biomarkers are measurable biological elements that reflect particular physiological or pathological states or predisposition towards diseases and they are currently widely studied in medicine and especially in CD. In this context, biomarkers can also be used to assess the severity or the evolution of several diseases, as well as the effectiveness of particular therapies. Genomics, transcriptomics, and proteomics have opened new windows on disease phenomena and may permit in the next future an effective development of novel diagnostic and prognostic medicine in order to better prevent or treat CD. This review will consider the current evidence of novel biomarkers with clear implications in the improvement of risk assessment, prevention strategies, and medical decision making in the field of CD.

A novel chemo-mechano-biological model of arterial tissue growth and remodelling

Arterial growth and remodelling (G&R) is mediated by vascular cells in response to their chemical and mechanical environment. To date, mechanical and biochemical stimuli tend to be modelled separately, however this ignores their complex interplay. Here, we present a novel mathematical model of arterial chemo-mechano-biology. We illustrate its application to the development of an inflammatory aneurysm in the descending human aorta. The arterial wall is modelled as a bilayer cylindrical non-linear elastic membrane, which is internally pressurised and axially stretched. The medial degradation that accompanies aneurysm development is driven by an inflammatory response. Collagen remodelling is simulated by adaption of the natural reference configuration of constituents; growth is simulated by changes in normalised mass-densities. We account for the distribution of attachment stretches that collagen fibres are configured to the matrix and, innovatively, allow this distribution to remodel. This enables the changing functional role of the adventitia to be simulated. Fibroblast-mediated collagen growth is represented using a biochemical pathway model: a system of coupled non-linear ODEs governs the evolution of fibroblast properties and levels of key biomolecules under the regulation of Transforming Growth Factor (TGF)-β, a key promoter of matrix deposition. Given physiologically realistic targets, different modes of aneurysm development can be captured, while the predicted evolution of biochemical variables is qualitatively consistent with trends observed experimentally. Interestingly, we observe that increasing the levels of collagen-promoting TGF-β results in arrest of aneurysm growth, which seems to be consistent with experimental evidence. We conclude that this novel Chemo-Mechano-Biological (CMB) mathematical model has the potential to provide new mechanobiological insight into vascular disease progression and therapy.

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.

Matrix Metalloproteinase Mediated Type I Collagen Degradation - An Independent Risk Factor for Mortality in Women

Chronic fibro-proliferative diseases are associated with nearly 45% of all deaths in the developed world. Matrix metalloproteinase (MMP) mediated remodeling of the extracellular matrix (ECM) plays an important role in disease development. Degradation of type I collagen is considered having a major role in this matter. C1M is a biomarker measuring type I collagen degradation fragments in blood. The aim of the current study was to investigate whether MMP mediated type I collagen degradation (C1M) was predictive of mortality in a large prospective cohort of Danish women aged 48–89 (n = 5855).

Subjects with high serum C1M showed significant increased mortality. The adjusted three year HR was 2.02 [95% CI: 1.48–2.76] for all-cause mortality, 2.32 [95% CI: 1.51–3.56] for cancer and 1.77 [95% CI: 0.98–3.17] for cardiovascular diseases. The adjusted nine year HR was 1.50 [95% CI: 1.28–1.75] for all-cause mortality, 1.49 [95% CI: 1.16–1.90] for cancer and 1.69 [95% CI: 1.27–2.24] for cardiovascular diseases.

High MMP-mediated type I collagen degradation was associated with increased mortality. Subjects with high C1M had a 2-fold increase in mortality compared to subjects with low levels of this collagen degradation product.

•

High MMP-mediated type I collagen degradation is an independent risk factor associated with a 2-fold increase in mortality.

•

A 2.3-fold increase in cancer mortality was found for subjects with high MMP-mediated type I collagen degradation.

•

Specific enzymatic processing of type I collagen is essential since only C1M and not CTX-I was associated with mortality.

Matrix metalloproteinase 10 is associated with disease severity and mortality in patients with peripheral arterial disease

OBJECTIVE

Peripheral arterial disease (PAD) is associated with poor prognosis in terms of cardiovascular (CV) morbidity and mortality. Matrix metalloproteinases (MMPs) contribute to vascular remodeling by degrading extracellular matrix components and play a role in atherosclerosis as demonstrated for MMP-10 (stromelysin-2). This study analyzed MMP-10 levels in PAD patients according to disease severity and CV risk factors and evaluated the prognostic value of MMP-10 for CV events and mortality in lower limb arterial disease after a follow-up period of 2 years.

METHODS

MMP-10 was measured by enzyme-linked immunosorbent assay in 187 PAD patients and 200 sex-matched controls.

RESULTS

PAD patients presented with increased levels of MMP-10 (702 ± 326 pg/mL control vs 946 ± 473 pg/mL PAD; P < .001) and decreased levels of tissue inhibitor of matrix metalloproteinase 1 (312 ± 117 ng/mL control vs 235 ± 110 ng/mL PAD; P < .001) compared with controls. Among PAD patients, those with critical limb ischemia (n = 88) showed higher levels of MMP-10 (1086 ± 478 pg/mL vs 822 ± 436 pg/mL; P < .001) compared with those with intermittent claudication (n = 99), whereas the MMP-10/tissue inhibitor of matrix metalloproteinase 1 ratio remained similar. The univariate analysis showed an association between MMP-10, age (P = .015), hypertension (P = .021), and ankle-brachial index (P = .006) in PAD patients that remained significantly associated with PAD severity after adjustment for other CV risk factors. Patients with the highest MMP-10 tertile had an increased incidence of all-cause mortality and CV mortality (P < .03).

CONCLUSIONS

Our results suggest that MMP-10 is associated with severity and poor outcome in PAD.

Matrix metalloproteinases in biologic samples

Matrix metalloproteinases (MMPs) are an important class of endopeptidases, having a role in a diverse range of physiological and pathological processes. This chapter provides an overview of the key regulatory processes in MMP production and activation. The common techniques used to assess MMP activity are discussed and their various strengths and weaknesses presented. This comparison of methodologies is specifically intended to aid any investigator who wishes to determine the most appropriate analytical method for their future studies because any investigation of MMPs in biological samples should be cognizant of the key mechanisms influencing the expression and activity of these proteinases. The endogenous, preanalytic and analytic chemistry of MMP activation influences the interpretation of the various techniques widely employed throughout the literature. Therefore, the ability to accurately evaluate the true endogenous activity of MMPs is heavily dependent on a clear understanding of these processes.

Gene expression levels of matrix metalloproteinases in human atherosclerotic plaques and evaluation of radiolabeled inhibitors as imaging agents for plaque vulnerability

INTRODUCTION

Atherosclerotic plaque rupture is the primary cause for myocardial infarction and stroke. During plaque progression macrophages and mast cells secrete matrix-degrading proteolytic enzymes, such as matrix metalloproteinases (MMPs). We studied levels of MMPs and tissue inhibitor of metalloproteinases-3 (TIMP-3) in relation to the characteristics of carotid plaques. We evaluated in vitro two radiolabeled probes targeting active MMPs towards non-invasive imaging of rupture-prone plaques.

METHODS

Human carotid plaques obtained from endarterectomy were classified into stable and vulnerable by visual and histological analysis. MMP-1, MMP-2, MMP-8, MMP-9, MMP-10, MMP-12, MMP-14, TIMP-3, and CD68 levels were investigated by quantitative polymerase chain reaction. Immunohistochemistry was used to localize MMP-2 and MMP-9 with respect to CD68-expressing macrophages. Western blotting was applied to detect their active forms. A fluorine-18-labeled MMP-2/MMP-9 inhibitor and a tritiated selective MMP-9 inhibitor were evaluated by in vitro autoradiography as potential lead structures for non-invasive imaging.

RESULTS

Gene expression levels of all MMPs and CD68 were elevated in plaques. MMP-1, MMP-9, MMP-12 and MMP-14 were significantly higher in vulnerable than stable plaques. TIMP-3 expression was highest in stable and low in vulnerable plaques. Immunohistochemistry revealed intensive staining of MMP-9 in vulnerable plaques. Western blotting confirmed presence of the active form in plaque lysates. In vitro autoradiography showed binding of both inhibitors to stable and vulnerable plaques.

CONCLUSIONS

MMPs differed in their expression patterns among plaque phenotypes, providing possible imaging targets. The two tested MMP-2/MMP-9 and MMP-9 inhibitors may be useful to detect atherosclerotic plaques, but not the vulnerable lesions selectively.

Low testosterone elevates interleukin family cytokines in a rodent model: a possible mechanism for the potentiation of vascular disease in androgen-deficient males

BACKGROUND

Androgen deficiency (AD) is associated with increased risk of atherosclerosis, cardiovascular, and peripheral arterial disease. Although the biochemical and molecular mechanisms underlying this risk remain unclear, higher testosterone (TST) levels correlate to significant immunoprotective molecular and cellular responses. Our group has previously demonstrated that female sex hormones influence vascular pathogenesis via inflammatory-modulated matrix metalloproteinase (MMP) regulation. Here we investigated the role of AD and androgen replacement therapy in the modulation of these hormonally responsive pathways that could be playing a role in the development of vascular pathogenesis.

METHODS

Aged orchiectomized male rats underwent TST supplementation per controlled release pellet implantation (0-150 mg). Young and aged intact groups served as controls. Serum was collected at 0-4 wk and analyzed by enzyme-linked immunosorbent assays, qualitative cytokine screening, and quantitative multiplex analyses. Human aortic smooth muscle cells were treated with 4,5α-dihydrotestosterone (DHT; 0-3000 nM) before or after interleukin 1β (IL-1β; 5 ng/mL) stimulation. Quantitative polymerase chain reaction and in-gel zymography was used to assay the effect on MMP expression and activity.

RESULTS

Subphysiological, physiological, and supraphysiological levels of TST were achieved with 0.5, 2.5, and 35 mg TST pellet implants in vivo, respectively. Inflammatory arrays indicated that interleukin cytokines, specifically IL-2, IL-6, IL-10, IL-12, and IL-13, were elevated at subphysiological level of TST, whereas TST supplementation decreased interleukins. Supraphysiological TST resulted in a significant increase in MMP-9 and tissue inhibitor of metalloproteinase-1 (TIMP-1) in vivo. Pretreatment with IL-1β slightly increased membrane type 1-MMP (MT1-MMP) and MMP-2 expression at low to mid-level DHT exposure in vitro, although these trends were not statistically significant.

CONCLUSIONS

Here we demonstrate AD is a proinflammatory modulator and indicate that MMP-independent mechanisms may play a role downstream of AD-induced inflammatory signaling in dysfunctional vascular remodeling. Future in vivo studies will examine AD and TST supplementation in acute inflammatory response to vascular injury and in MMP-modulated vascular disease.

Encapsulated microbubbles and echogenic liposomes for contrast ultrasound imaging and targeted drug delivery

Micron- to nanometer-sized ultrasound agents, like encapsulated microbubbles and echogenic liposomes, are being developed for diagnostic imaging and ultrasound mediated drug/gene delivery. This review provides an overview of the current state of the art of the mathematical models of the acoustic behavior of ultrasound contrast microbubbles. We also present a review of the in vitro experimental characterization of the acoustic properties of microbubble based contrast agents undertaken in our laboratory. The hierarchical two-pronged approach of modeling contrast agents we developed is demonstrated for a lipid coated (Sonazoid™) and a polymer shelled (poly D-L-lactic acid) contrast microbubbles. The acoustic and drug release properties of the newly developed echogenic liposomes are discussed for their use as simultaneous imaging and drug/gene delivery agents. Although echogenicity is conclusively demonstrated in experiments, its physical mechanisms remain uncertain. Addressing questions raised here will accelerate further development and eventual clinical approval of these novel technologies.

Expression of matrix metalloproteinase-12 in aortic dissection

BACKGROUND

Aortic dissection(AD) is an acute process of large blood vessels characterized by dangerous pathogenic conditions and high disability and high mortality. The pathogenesis of AD remains debated. Matrix metalloproteinase-12 (MMP-12) participates in many pathological processes such as abdominal aortic aneurysm, atherosclerosis, emphysema and cancer. However, this elastase has rarely been assessed in the presence of AD. The aim of the present study was to investigate the expression of MMP-12 in aortic tissue so as to offer a better understanding of the possible mechanisms of AD.

METHODS

The protein expression levels of MMP-12 were analyzed and compared in aorta tissue and the blood serum samples by reverse transcription polymerase chain reaction(RT-PCR), Western blotting, immuno-histochemistry, fluorescence resonance energy transfer ( FRET ) activity assay and enzyme-linked immuno sorbent assay ( ELISA ), respectively. Ascending aorta tissue specimens were obtained from 12 patients with an acute Stanford A-dissection at the time of aortic replacement, and from 4 patients with coronary artery disease (CAD) undergoing coronary artery bypass surgery. Meanwhile, serum samples were harvested from 15 patients with an acute Stanford A-dissection and 10 healthy individuals who served as the control group.

RESULTS

MMP-12 activity could be detected in both AD and CAD groups, but the level in the AD group was higher than those in the CAD group (P < 0.05). MMP-12 proteolysis existed in both serum samples of the AD and healthy groups, and the activity level in the AD group was clearly higher than in the healthy group (P < 0.05). For AD patients, MMP-12 activity in serum was higher than in the aorta wall (P < 0.05). MMP-12 activity in the aortic wall tissue can be inhibited by MMP inhibitor v (P < 0.05).

CONCLUSION

The present study directly demonstrates that MMP-12 proteolytic activity exists within the aorta specimens and blood samples from aortic dissection patients. MMP-12 might be of potential relevance as a clinically diagnostic tool and therapeutic target in vascular injury and repair.

Pathophysiological roles and clinical importance of biomarkers in acute coronary syndrome

Early diagnosis of acute coronary syndrome (ACS) is important to guide appropriate therapy at a time when it is most likely to be of value. Accurate prognostic and risk stratification will facilitate high-risk patients to have early advanced diagnostic investigations and early appropriate interventions in a cost-effective and efficient manner, while those patients at low risk of ACS complications do not need such costly diagnostic tests and unnecessary hospital admission. Recent investigations have demonstrated that elevation of biomarkers upstream from acute-phase biomarkers, biomarkers of plaque destabilization and rupture, biomarkers of myocardial ischemia, necrosis, and dysfunction may provide an earlier assessment of patient risk and identify patients with higher risk of having an adverse event. This review provides an overview of the pathophysiology and clinical characteristics of several well-established biomarkers as well as emerging biomarkers that may have potential clinical utility in patients with ACS. Such emerging biomarkers hold promise and need to be more thoroughly evaluated before utilization in routine clinical practice.