Matrix metalloproteinase-2 on activated platelets triggers endothelial PAR-1 initiating atherosclerosis

Phenolic profile, cheminformatics, and antiplatelet aggregation activity of orange and purple sweet potato (Ipomoea batatas L.) storage roots

Sweet potatoes are rich in cardioprotective phytochemicals with potential anti-platelet aggregation activity, although this benefit may vary among cultivars/genotypes. The phenolic profile [HPLC-ESI(-)-qTOF-MS2], cheminformatics (ADMET properties, affinity toward platelet proteins) and anti-PA activity of phenolic-rich hydroalcoholic extracts obtained from orange (OSP) and purple (PSP) sweet potato storage roots, was evaluated. The phenolic richness [Hydroxycinnamic acids> flavonoids> benzoic acids] was PSP > OSP. Their main chlorogenic acids could interact with platelet proteins (integrins/adhesins, kinases/metalloenzymes) but their bioavailability could be poor. Just OSP exhibited a dose-dependent anti-platelet aggregation activity [inductor (IC50, mg.ml-1): thrombin receptor activator peptide-6 (0.55) > Adenosine-5'-diphosphate (1.02) > collagen (1.56)] and reduced P-selectin expression (0.75-1.0 mg.ml-1) but not glycoprotein IIb/IIIa secretion. The explored anti-PA activity of OSP/PSP seems to be inversely related to their phenolic richness. The poor first-pass bioavailability of its chlorogenic acids (documented in silico) may represent a further obstacle for their anti-PA in vivo.

Recent advances in targeted therapy for inflammatory vascular diseases

Vascular diseases constitute a significant contributor to worldwide mortality rates, placing a substantial strain on healthcare systems and socio-economic aspects. They are closely associated with inflammatory responses, as sustained inflammation could impact endothelial function, the release of inflammatory mediators, and platelet activation, thus accelerating the progression of vascular diseases. Consequently, directing therapeutic efforts towards mitigating inflammation represents a crucial approach in the management of vascular diseases. Traditional anti-inflammatory medications may have extensive effects on multiple tissues and organs when absorbed through the bloodstream. Conversely, treatments targeting inflammatory vascular diseases, such as monoclonal antibodies, drug-eluting stents, and nano-drugs, can achieve more precise effects, including precise intervention, minimal non-specific effects, and prolonged efficacy. In addition, personalized therapy is an important development trend in targeted therapy for inflammatory vascular diseases. Leveraging advanced simulation algorithms and clinical trial data, treatment strategies are gradually being personalized based on patients' genetic, biomarker, and clinical profiles. It is expected that the application of precision medicine in the field of vascular diseases will have a broader future. In conclusion, targeting therapies offer enhanced safety and efficacy compared to conventional medications; investigating novel targeting therapies and promoting clinical transformation may be a promising direction in improving the prognosis of patients with inflammatory vascular diseases. This article reviews the pathogenesis of inflammatory vascular diseases and presents a comprehensive overview of the potential for targeted therapies in managing this condition.

Neutrophil extracellular traps: a catalyst for atherosclerosis

Neutrophil extracellular traps (NETs) are network-like structures released by activated neutrophils. They consist mainly of double-stranded DNA, histones, and neutrophil granule proteins. Continuous release of NETs in response to external stimuli leads to activation of surrounding platelets and monocytes/macrophages, resulting in damage to endothelial cells (EC) and vascular smooth muscle cells (VSMC). Some clinical trials have demonstrated the association between NETs and the severity and prognosis of atherosclerosis. Furthermore, experimental findings have shed light on the molecular mechanisms by which NETs contribute to atherogenesis. NETs play a significant role in the formation of atherosclerotic plaques. This review focuses on recent advancements in the understanding of the relationship between NETs and atherosclerosis. It explores various aspects, including the formation of NETs in atherosclerosis, clinical trials investigating NET-induced atherosclerosis, the mechanisms by which NETs promote atherogenesis, and the translational implications of NETs. Ultimately, we aim to propose new research directions for the diagnosis and treatment of atherosclerosis.

LncRNA PSMB8-AS1 Instigates Vascular Inflammation to Aggravate Atherosclerosis

BACKGROUND

Increasing evidence suggests that long noncoding RNAs play significant roles in vascular biology and disease development. One such long noncoding RNA, PSMB8-AS1, has been implicated in the development of tumors. Nevertheless, the precise role of PSMB8-AS1 in cardiovascular diseases, particularly atherosclerosis, has not been thoroughly elucidated. Thus, the primary aim of this investigation is to assess the influence of PSMB8-AS1 on vascular inflammation and the initiation of atherosclerosis.

METHODS

We generated PSMB8-AS1 knockin and Apoe (Apolipoprotein E) knockout mice (Apoe-/-PSMB8-AS1KI) and global Apoe and proteasome subunit-β type-9 (Psmb9) double knockout mice (Apoe-/-Psmb9-/-). To explore the roles of PSMB8-AS1 and Psmb9 in atherosclerosis, we fed the mice with a Western diet for 12 weeks.

RESULTS

Long noncoding RNA PSMB8-AS1 is significantly elevated in human atherosclerotic plaques. Strikingly, Apoe-/-PSMB8-AS1KI mice exhibited increased atherosclerosis development, plaque vulnerability, and vascular inflammation compared with Apoe-/- mice. Moreover, the levels of VCAM1 (vascular adhesion molecule 1) and ICAM1 (intracellular adhesion molecule 1) were significantly upregulated in atherosclerotic lesions and serum of Apoe-/-PSMB8-AS1KI mice. Consistently, in vitro gain- and loss-of-function studies demonstrated that PSMB8-AS1 induced monocyte/macrophage adhesion to endothelial cells and increased VCAM1 and ICAM1 levels in a PSMB9-dependent manner. Mechanistic studies revealed that PSMB8-AS1 induced PSMB9 transcription by recruiting the transcription factor NONO (non-POU domain-containing octamer-binding protein) and binding to the PSMB9 promoter. PSMB9 (proteasome subunit-β type-9) elevated VCAM1 and ICAM1 expression via the upregulation of ZEB1 (zinc finger E-box-binding homeobox 1). Psmb9 deficiency decreased atherosclerotic lesion size, plaque vulnerability, and vascular inflammation in Apoe-/- mice in vivo. Importantly, endothelial overexpression of PSMB8-AS1-increased atherosclerosis and vascular inflammation were attenuated by Psmb9 knockout.

CONCLUSIONS

PSMB8-AS1 promotes vascular inflammation and atherosclerosis via the NONO/PSMB9/ZEB1 axis. Our findings support the development of new long noncoding RNA-based strategies to counteract atherosclerotic cardiovascular disease.

Anti-atherosclerotic effects and molecular targets of ginkgolide B from Ginkgo biloba

Bioactive compounds derived from herbal medicinal plants modulate various therapeutic targets and signaling pathways associated with cardiovascular diseases (CVDs), the world's primary cause of death. Ginkgo biloba , a well-known traditional Chinese medicine with notable cardiovascular actions, has been used as a cardio- and cerebrovascular therapeutic drug and nutraceutical in Asian countries for centuries. Preclinical studies have shown that ginkgolide B, a bioactive component in Ginkgo biloba , can ameliorate atherosclerosis in cultured vascular cells and disease models. Of clinical relevance, several clinical trials are ongoing or being completed to examine the efficacy and safety of ginkgolide B-related drug preparations in the prevention of cerebrovascular diseases, such as ischemia stroke. Here, we present a comprehensive review of the pharmacological activities, pharmacokinetic characteristics, and mechanisms of action of ginkgolide B in atherosclerosis prevention and therapy. We highlight new molecular targets of ginkgolide B, including nicotinamide adenine dinucleotide phosphate oxidases (NADPH oxidase), lectin-like oxidized LDL receptor-1 (LOX-1), sirtuin 1 (SIRT1), platelet-activating factor (PAF), proprotein convertase subtilisin/kexin type 9 (PCSK9) and others. Finally, we provide an overview and discussion of the therapeutic potential of ginkgolide B and highlight the future perspective of developing ginkgolide B as an effective therapeutic agent for treating atherosclerosis.

Platelet biology and function: plaque erosion vs. rupture

The leading cause of heart disease in developed countries is coronary atherosclerosis, which is not simply a result of ageing but a chronic inflammatory process that can lead to acute clinical events upon atherosclerotic plaque rupture or erosion and arterial thrombus formation. The composition and location of atherosclerotic plaques determine the phenotype of the lesion and whether it is more likely to rupture or to erode. Although plaque rupture and erosion both initiate platelet activation on the exposed vascular surface, the contribution of platelets to thrombus formation differs between the two phenotypes. In this review, plaque phenotype is discussed in relation to thrombus composition, and an overview of important mediators (haemodynamics, matrix components, and soluble factors) in plaque-induced platelet activation is given. As thrombus formation on disrupted plaques does not necessarily result in complete vessel occlusion, plaque healing can occur. Therefore, the latest findings on plaque healing and the potential role of platelets in this process are summarized. Finally, the clinical need for more effective antithrombotic agents is highlighted.

The Systemic Inflammation Index Predicts Poor Clinical Prognosis in Patients with Initially Diagnosed Acute Coronary Syndrome Undergoing Primary Coronary Angiography

Background

Systemic inflammation index (SII: neutrophil count * platelet count/lymphocyte count) is a new inflammatory marker that can reflect the degree of systemic inflammatory response after coronary artery disease (CAD). However, the predictive value of the SII for clinical prognosis in patients with initially diagnosed acute coronary syndrome (ACS) has yet to be thoroughly studied.

Patients and Methods

Patients with initially diagnosed ACS who underwent primary coronary angiography in our hospital from January 2019 to April 2021 were included in this study. 757 patients with ACS who underwent primary coronary angiography were enrolled. According to the baseline SII level, the patients were divided into a high SII group and a low SII group. The primary endpoint was major cardiovascular events (MACEs), defined as cardiac death, non-fatal myocardial infarction (MI), and non-fatal stroke.

Results

At a median follow-up of 33.9 months, 140 (18.5%) MACEs were recorded. Receiver operating characteristic (ROC) curve analysis showed that SII's best cut-off value for predicting MACEs was 713.9*109/L. Kaplan-Meier survival curve analysis showed that the survival rate of the low SII group was higher than the high SII group (P<0.001). Compared with the low SII group, the risk of MACEs was significantly increased in the high SII group (89 cases (33.3%) vs.51 patients (10.4%), P<0.001). Univariate and multivariate Cox regression analysis manifested that high SII level was independently associated with the occurrence of MACEs in patients with ACS undergoing primary coronary angiography (adjusted hazard ratio [HR]: 2.915, 95% confidence interval (CI%): 1.830-4.641, P<0.001). Adding SII to the conventional risk factor model improved the predictive value of MACEs.

Conclusion

This study showed that elevated SII was associated with adverse cardiovascular prognosis in patients with ACS undergoing primary coronary angiography, making SII a valuable predictor of poor prognosis in patients with ACS undergoing primary coronary angiography.

MMP-2 Associates With Incident Heart Failure and Atrial Fibrillation: The ARIC Study

BACKGROUND

MMP (matrix metalloproteinase)-2 participates in extracellular matrix regulation and may be involved in heart failure (HF), atrial fibrillation (AF), and coronary heart disease.

METHODS

Among the 4693 ARIC study (Atherosclerosis Risk in Communities) participants (mean age, 75±5 years; 42% women) without prevalent HF, multivariable Cox proportional hazard models were used to estimate associations of plasma MMP-2 levels with incident HF, HF with preserved ejection fraction (≥50%), HF with reduced ejection fraction (<50%), AF, and coronary heart disease. Mediation of the association between MMP-2 and HF was assessed by censoring participants who developed AF or coronary heart disease before HF. Multivariable linear regression models were used to assess associations of MMP-2 with measures of left ventricular and left atrial structure and function.

RESULTS

Compared with the 3 lower quartiles, the highest MMP-2 quartile associated with greater risk of incident HF overall (adjusted hazard ratio, 1.48 [95% CI, 1.21-1.81]), incident HF with preserved ejection fraction (1.44 [95% CI, 1.07-1.94]), incident heart failure with reduced ejection fraction (1.48 [95% CI, 1.08-2.02]), and incident AF (1.44 [95% CI, 1.18-1.77]) but not incident coronary heart disease (0.97 [95% CI, 0.71-1.34]). Censoring AF attenuated the MMP-2 association with HF with preserved ejection fraction. Higher plasma MMP-2 levels were associated with larger left ventricular end-diastolic volume index, greater left ventricular mass index, higher E/e' ratio, larger left atrial volume index, and worse left atrial reservoir and contractile strains (all P<0.001).

CONCLUSIONS

Higher plasma MMP-2 levels associate with diastolic dysfunction, left atrial dysfunction, and a higher risk of incident HF and AF. AF is a mediator of MMP-2-associated HF with preserved ejection fraction risk.

Intestinal proteases

PURPOSE OF REVIEW

Proteases constitute a group of enzymes that hydrolyze peptide bonds. Intestinal proteases are an integral part of gut homeostasis and digestion. This review discusses the broader classification of proteases, regulation of proteolytic activity (PA) in the intestinal tract, and how dysregulation of intestinal proteases contributes to the pathophysiology of conditions such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and celiac disease. We also discuss recent advancements in therapeutic modulation that directly or indirectly target intestinal proteases and can be utilized to treat these illnesses.

RECENT FINDINGS

Host and microbiota derived proteases have been associated with symptoms in subsets of patients with IBS, IBD and celiac disease. Elevated PA mediates barrier dysfunction, visceral hypersensitivity as well as immune activation and inflammation. Recent mechanistic studies have revealed the nature of disease-associated proteases and mechanisms regulating their activity, particularly those driven by the microbiota. Advancements in activity-based probes have allowed novel ways of in vivo imaging of PA. Newer strategies targeting proteases include monoclonal antibodies, engineered microbiota as well as specific protease inhibitors.

SUMMARY

Significant progresses made in the detection as well as regulation of PA is likely to provide therapeutic advancements for gastrointestinal diseases.

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.

Identification of miR-143-3p as a diagnostic biomarker in gastric cancer

BACKGROUND

Gastric cancer (GC) is among the most common types of gastrointestinal cancers and has a high incidence and mortality around the world. To suppress the progression of GC, it is essential to develop diagnostic markers. MicroRNAs regulate GC development, but a clearer insight into their role is needed before they can be applied as a molecular markers and targets.

METHODS

In this study, we assessed the diagnostic value of differentially expressed microRNAs as potential diagnostic biomarkers for GC using data for 389 tissue samples from the Cancer Genome Atlas (TCGA) and 21 plasma samples from GC patients.

RESULTS

The expression of hsa-miR-143-3p (also known as hsa-miR-143) was significantly downregulated in GC according to the TCGA data and plasma samples. The 228 potential target genes of hsa-miR-143-3p were analyzed using a bioinformatics tool for miRNA target prediction. The target genes correlated with extracellular matrix organization, the cytoplasm, and identical protein binding. Furthermore, the pathway enrichment analysis of target genes showed that they were involved in pathways in cancer, the phosphoinositide 3-kinase (PI3K)-protein kinase B (Akt) signaling pathway, and proteoglycans in cancer. The hub genes in the protein-protein interaction (PPI) network, were matrix metallopeptidase 2 (MMP2), CD44 molecule (CD44), and SMAD family member 3 (SMAD3).

CONCLUSIONS

This study suggests that hsa-miR-143-3p may be used as a diagnostic marker for GC, contributing via the pathways involved in the development of GC.

Platelet-monocyte aggregates: molecular mediators of thromboinflammation

Platelets, key facilitators of primary hemostasis and thrombosis, have emerged as crucial cellular mediators of innate immunity and inflammation. Exemplified by their ability to alter the phenotype and function of monocytes, activated platelets bind to circulating monocytes to form monocyte-platelet aggregates (MPA). The platelet-monocyte axis has emerged as a key mechanism connecting thrombosis and inflammation. MPA are elevated across the spectrum of inflammatory and autoimmune disorders, including cardiovascular disease, systemic lupus erythematosus (SLE), and COVID-19, and are positively associated with disease severity. These clinical disorders are all characterized by an increased risk of thromboembolic complications. Intriguingly, monocytes in contact with platelets become proinflammatory and procoagulant, highlighting that this interaction is a central element of thromboinflammation.

Circulating Biomarkers for Laboratory Diagnostics of Atherosclerosis-Literature Review

Atherosclerosis is still considered a disease burden with long-term damaging processes towards the cardiovascular system. Evaluation of atherosclerotic stages requires the use of independent markers such as those already considered traditional, that remain the main therapeutic target for patients with atherosclerosis, together with emerging biomarkers. The challenge is finding models of predictive markers that are particularly tailored to detect and evaluate the evolution of incipient vascular lesions. Important advances have been made in this field, resulting in a more comprehensible and stronger linkage between the lipidic profile and the continuous inflammatory process. In this paper, we analysed the most recent data from the literature studying the molecular mechanisms of biomarkers and their involvement in the cascade of events that occur in the pathophysiology of atherosclerosis.

Integrating Mechanisms in Thrombotic Peripheral Arterial Disease

Peripheral arterial disease (PAD), a manifestation of systemic atherosclerosis, is underdiagnosed in the general population. Despite the extensive research performed to unravel its pathophysiology, inadequate knowledge exists, thus preventing the development of new treatments. This review aims to highlight the essential elements of atherosclerosis contributing to the pathophysiology of PAD. Furthermore, emphasis will be placed on the role of thrombo-inflammation, with particular focus on platelet and coagulation activation as well as cell-cell interactions. Additional insight will be then discussed to reveal the contribution of hypercoagulability to the development of vascular diseases such as PAD. Lastly, the current antithrombotic treatments will be discussed, and light will be shed on promising new targets aiming to aid the development of new treatments.

The NO/cGMP/PKG pathway in platelets: The therapeutic potential of PDE5 inhibitors in platelet disorders

Platelets are the "guardians" of the blood circulatory system. At sites of vessel injury, they ensure hemostasis and promote immunity and vessel repair. However, their uncontrolled activation is one of the main drivers of thrombosis. To keep circulating platelets in a quiescent state, the endothelium releases platelet antagonists including nitric oxide (NO) that acts by stimulating the intracellular receptor guanylyl cyclase (GC). The latter produces the second messenger cyclic guanosine-3',5'-monophosphate (cGMP) that inhibits platelet activation by stimulating protein kinase G, which phosphorylates hundreds of intracellular targets. Intracellular cGMP pools are tightly regulated by a fine balance between GC and phosphodiesterases (PDEs) that are responsible for the hydrolysis of cyclic nucleotides. Phosphodiesterase type 5 (PDE5) is a cGMP-specific PDE, broadly expressed in most tissues in humans and rodents. In clinical practice, PDE5 inhibitors (PDE5i) are used as first-line therapy for erectile dysfunction, pulmonary artery hypertension, and lower urinary tract symptoms. However, several studies have shown that PDE5i may ameliorate the outcome of various other conditions, like heart failure and stroke. Interestingly, NO donors and cGMP analogs increase the capacity of anti-platelet drugs targeting the purinergic receptor type Y, subtype 12 (P2Y12) receptor to block platelet aggregation, and preclinical studies have shown that PDE5i inhibits platelet functions. This review summarizes the molecular mechanisms underlying the effect of PDE5i on platelet activation and aggregation focusing on the therapeutic potential of PDE5i in platelet disorders, and the outcomes of a combined therapy with PDE5i and NO donors to inhibit platelet activation.

Low-molecular-weight fucoidan bidirectionally regulates lipid uptake and cholesterol efflux through the p38 MAPK phosphorylation

Atherosclerosis (AS) is the pathological basis of many cardiovascular and cerebrovascular diseases, in which macrophage-derived foam cells are the critical step and a typical pathological feature of early atherosclerosis. We previously confirmed that low-molecular-weight fucoidan (LMWF) had a good anti-AS effect, but the mechanism is still unclear. Here with aim to investigate the inhibitory effect of LMWF on foam cells and its molecular mechanism. Oil red O staining showed that LMWF effectively alleviated lipid accumulation and the formation of foam cells. Flow cytometry detection showed that LMWF promoted foam cells apoptosis. In addition, immunofluorescence showed that LMWF inhibited macrophage scavenger receptor A1 (SR-A1)-mediated lipid uptake and promoted ATP-binding cassette transporter A1 (ABCA1)-mediated cholesterol outflow. Western blot showed that LMWF downregulated SR-A1 protein expression and upregulated ABCA1 protein expression by inhibiting p38 mitogen activated protein kinase (p38MAPK) phosphorylation. Moreover, the mRNA transcriptions of Stat1, Elk-1, and Myc were downregulated when treated with LMWF. It concluded that, LMWF achieved bidirectional regulation of SR-A1 and ABCA1, then prevented the formation of foam cells, finally ameliorated the development of AS.

The role of platelets, neutrophils and endothelium in COVID-19 infection

INTRODUCTION

COVID-19 is associated to an increased risk of thrombosis, as a result of a complex process that involves the activation of vascular and circulating cells, the release of soluble inflammatory and thrombotic mediators and blood clotting activation.

AREAS COVERED

This article reviews the pathophysiological role of platelets, neutrophils and the endothelium, and of their interactions, in the thrombotic complications of COVID-19 patients, and the current and future therapeutic approaches targeting these cell types.

EXPERT OPINION

Virus-induced platelet, neutrophil and endothelial cell changes are crucial triggers of the thrombotic complications and of the adverse evolution of COVID-19. Both the direct interaction with the virus and the associated cytokine storm concur to trigger cell activation in a classical thromboinflammatory vicious circle. Although heparin has proven to be an effective prophylactic and therapeutic weapon for the prevention and treatment of COVID-19-associated thrombosis, it acts downstream of the cascade of events triggered by SARS-CoV-2. The identification of specific molecular targets interrupting the thromboinflammatory cascade upstream, and more specifically acting either on the interaction of SARS-CoV-2 with blood and vascular cells or on the specific signalling mechanisms associated with their COVID-19-associated activation, might theoretically offer greater protection with potentially lesser side effects.

Sex differences at the platelet-vascular interface

Platelets are multifunctional cells that ensure the integrity of the vascular wall and modulate the immune response at the blood/vascular interface. Their pathological activation results in both thrombosis and inflammation and implicates them in the pathogenesis of vascular disease. Vascular diseases are sexually dimorphic in terms of incidence, clinical presentation, outcome, and efficacy of anti-platelet therapy. We here provide an overview of what is known about the role of platelets in the initiation and progression of vascular diseases and summarize what is known about the sex differences in platelet reactivity and in the thromboinflammatory mechanisms that drive these diseases, with a particular focus on atherosclerosis, obstructive and non-obstructive coronary artery disease, and ischemic stroke. Understanding the sex differences at the platelet-vascular interface is clinically relevant as it will enable: (1) to design new therapeutic strategies that prevent the detrimental effects of the immune-modulatory function of platelets taking sex into account, and (2) to evaluate if sex-specific anti-platelet drug regimens should be used to reduce the risk not only of thrombosis but also of vascular disease progression.

Release of MMP-2 in the circulation of patients with acute coronary syndromes undergoing percutaneous coronary intervention: Role of platelets

INTRODUCTION

Matrix metalloproteinases (MMPs) of atherosclerotic tissue contribute to plaque rupture triggering acute coronary syndromes (ACS). Several MMPs, including MMP-2, are also contained in platelets and released upon activation. An increase in circulating levels of MMP-2 has been reported in patients undergoing percutaneous coronary interventions (PCI), but its time-course and origin remain unclear. Aims of our study were to assess the time-course of MMP-2 release in blood of stable and unstable coronary artery disease patients undergoing PCI and to unravel the possible contribution of platelets to its release.

METHODS

Peripheral blood samples were drawn immediately before, 4 and 24 h after PCI from patients with ACS (NSTEMI or STEMI, n = 21) or with stable angina (SA, n = 21). Platelet-poor plasma and washed platelet lysates were prepared and stored for subsequent assay of MMP-2 and β-thromboglobulin (β-TG), a platelet-specific protein released upon activation.

RESULTS

Plasma MMP-2 and β-TG increased significantly 4 h after PCI and returned to baseline at 24 h in ACS patients, while they did not change in SA patients. Platelet content of MMP-2 and β-TG decreased significantly 4 h after PCI in patients with ACS, compatible with intravascular platelet activation and release, while they did not change in patients with SA.

CONCLUSIONS

PCI triggers the release of MMP-2 in the circulation of ACS patients but not in that of patients with SA. Platelets activated by PCI contribute to the increase of plasma MMP-2 releasing their MMP-2 content. Given that previous mechanicistic studies have shown that MMP-2 may sustain platelet activation and unstabilize downstream-located plaques and in the long term favour restenosis and atherosclerosis progression, these data may encourage the search for therapeutic agents blocking MMP-2 release or activity in ACS.