An anti-von Willebrand factor aptamer reduces platelet adhesion among patients receiving aspirin and clopidogrel in an ex vivo shear-induced arterial thrombosis

Non-coding RNA therapeutics in cardiovascular diseases and risk factors: Systematic review

At present, RNA-based therapy which includes therapies using non-coding RNAs (ncRNAs), antisense oligonucleotides (ASOs), and aptamers are gaining widespread attention as possible ways to target genes in various cardiovascular diseases (CVDs), thereby serving as a promising therapeutic approach for CVDs and risk factors management. However, data are primarily in an early stage. A systematic review was carried out using literature from several databases (Pubmed, Cochrane, Scopus, and DOAJR) following the PRISMA guidelines. Of the 64 articles reviewed, 39 papers were included in this review with three main types of RNAs: aptamers, antisense oligonucleotides (ASOs), and small-interfering RNA (siRNA). All studies were human clinical trials. RNA-based therapies were demonstrated to be efficacious in treating various CVDs and controlling cardiovascular risk factors. They are generally safe and well-tolerated. However, data are still in the early stage and warrant further investigation.

Targeting extracellular CIRP with an X-aptamer shows therapeutic potential in acute pancreatitis

Severe acute pancreatitis (AP) is associated with a high mortality rate. Cold-inducible RNA binding protein (CIRP) can be released from cells in inflammatory conditions and extracellular CIRP acts as a damage-associated molecular pattern. This study aims to explore the role of CIRP in the pathogenesis of AP and evaluate the therapeutic potential of targeting extracellular CIRP with X-aptamers. Our results showed that serum CIRP concentrations were significantly increased in AP mice. Recombinant CIRP triggered mitochondrial injury and ER stress in pancreatic acinar cells. CIRP^-/- mice suffered less severe pancreatic injury and inflammatory responses. Using a bead-based X-aptamer library, we identified an X-aptamer that specifically binds to CIRP (XA-CIRP). Structurally, XA-CIRP blocked the interaction between CIRP and TLR4. Functionally, it reduced CIRP-induced pancreatic acinar cell injury in vitro and L-arginine-induced pancreatic injury and inflammation in vivo. Thus, targeting extracellular CIRP with X-aptamers may be a promising strategy to treat AP.

Platelet-Leucocyte Aggregates as Novel Biomarkers in Cardiovascular Diseases

Simple Summary

Cardiovascular diseases are the most common cause of death worldwide. Hence, novel biomarkers are urgently needed to improve diagnosis and treatment. Platelet–leucocyte aggregates are conglomerates of platelets and leucocytes and are widely investigated as biomarkers in cardiovascular diseases. Platelet–leucocytes aggregates are present in health, but increase in patients with cardiovascular risk factors and acute or stable coronary syndromes, making them a potential diagnostic marker. Moreover, platelet–leucocyte aggregates predict outcomes after surgery or percutaneous treatment and could be used to monitor antiplatelet therapy. Emerging data about the participation of platelet–leucocyte aggregates in cardiovascular diseases pathogenesis make them an attractive target for novel therapies. Furthermore, simple detection with conventional flow cytometry provides accurate and reproducible results, although requires specific sample handling. The main task for the future is to determine the standardized protocol to measure blood concentrations of platelet–leucocyte aggregates and subsequently establish their normal range in health and disease.

Abstract

Platelet–leucocyte aggregates (PLA) are a formation of leucocytes and platelets bound by specific receptors. They arise in the condition of sheer stress, thrombosis, immune reaction, vessel injury, and the activation of leukocytes or platelets. PLA participate in cardiovascular diseases (CVD). Increased levels of PLA were revealed in acute and chronic coronary syndromes, carotid stenosis cardiovascular risk factors. Due to accessible, available, replicable, quick, and low-cost quantifying using flow cytometry, PLA constitute an ideal biomarker for clinical practice. PLA are promising in early diagnosing and estimating prognosis in patients with acute or chronic coronary syndromes treated by percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). PLA were also a reliable marker of platelet activity for monitoring antiplatelet therapy. PLA consist also targets potential therapies in CVD. All of the above potential clinical applications require further studies to validate methods of assay and proof clinical benefits.

Overview of the Therapeutic Potential of Aptamers Targeting Coagulation Factors

Aptamers are single-stranded DNA or RNA sequences that bind target molecules with high specificity and affinity. Aptamers exhibit several notable advantages over protein-based therapeutics. Aptamers are non-immunogenic, easier to synthesize and modify, and can bind targets with greater affinity. Due to these benefits, aptamers are considered a promising therapeutic candidate to treat various conditions, including hematological disorders and cancer. An active area of research involves developing aptamers to target blood coagulation factors. These aptamers have the potential to treat cardiovascular diseases, blood disorders, and cancers. Although no aptamers targeting blood coagulation factors have been approved for clinical use, several aptamers have been evaluated in clinical trials and many more have demonstrated encouraging preclinical results. This review summarized our knowledge of the aptamers targeting proteins involved in coagulation, anticoagulation, fibrinolysis, their extensive applications as therapeutics and diagnostics tools, and the challenges they face for advancing to clinical use.

Progress in the development of antiplatelet agents: Focus on the targeted molecular pathway from bench to clinic

Antiplatelet drugs serve as a first-line antithrombotic therapy for the management of acute ischemic events and the prevention of secondary complications in vascular diseases. Numerous antiplatelet therapies have been developed; however, currently available agents are still associated with inadequate efficacy, risk of bleeding, and variability in individual response. Understanding the mechanisms of platelet involvement in thrombosis and the clinical development process of antiplatelet agents is critical for the discovery of novel agents. The functions of platelets in thrombosis are regulated by two major mechanisms: the interaction between surface receptors and their ligands, and the downstream intracellular signaling pathways. Recently, most of the progress made in antiplatelet drug development has been achieved with P2Y receptor antagonists. Additionally, the usage of GP IIb/IIIa receptor antagonists has decreased, because it is associated with a higher risk of bleeding and thrombocytopenia. Agents targeting other platelet surface receptors such as PARs, TP receptor, EP3 receptor, GPIb-IX-V receptor, P-selectin, as well as intracellular signaling factors, such as PI3Kβ, have been evaluated in an attempt to develop the next generation of antiplatelet drugs, reduce or eliminate interpatient variability of drug efficacy and significantly lower the risk of drug-induced bleeding. The aim of this review is to describe the pathways of platelet activation in thrombosis, and summarize the development process of antiplatelet agents, as well as the preclinical and clinical evaluations performed on these agents.

Using Genome Sequence to Enable the Design of Medicines and Chemical Probes

Rapid progress in genome sequencing technology has put us firmly into a postgenomic era. A key challenge in biomedical research is harnessing genome sequence to fulfill the promise of personalized medicine. This Review describes how genome sequencing has enabled the identification of disease-causing biomolecules and how these data have been converted into chemical probes of function, preclinical lead modalities, and ultimately U.S. Food and Drug Administration (FDA)-approved drugs. In particular, we focus on the use of oligonucleotide-based modalities to target disease-causing RNAs; small molecules that target DNA, RNA, or protein; the rational repurposing of known therapeutic modalities; and the advantages of pharmacogenetics. Lastly, we discuss the remaining challenges and opportunities in the direct utilization of genome sequence to enable design of medicines.

Platelet receptors as therapeutic targets: Past, present and future

Anti-platelet drugs reduce arterial thrombosis after plaque rupture and erosion, prevent stent thrombosis and are used to prevent and treat myocardial infarction and ischaemic stroke. Some of them may also be helpful in treating less frequent diseases such as thrombotic thrombocytopenic purpura. The present concise review aims to cover current and future developments of anti-platelet drugs interfering with the interaction of von Willebrand factor (VWF) with glycoprotein (GP) Ibα, and directed against GPVI, GPIIb/IIIa (integrin αIIbβ3), the thrombin receptor PAR-1, and the ADP receptor P2Y12. The high expectations of having novel antiplatelet drugs which selectively inhibit arterial thrombosis without interfering with normal haemostasis could possibly be met in the near future.

Assessment of the Diagnostic Value of Plasma Levels, Activities, and Their Ratios of von Willebrand Factor and ADAMTS13 in Patients with Cerebral Infarction

BACKGROUND AND OBJECTIVES

Raised levels of von Willebrand factor (VWF) and reduced levels of a disintegrin and a metalloproteinase with a thrombospondin type I motif, member 13 (ADAMTS13) activity are associated with thrombosis. We aimed to investigate the relationships between plasma levels of VWF and ADAMTS13, their ratios, and the occurrence of cerebral infarction and to understand the roles of VWF and ADAMTS13 in cerebral infarction.

METHODS

Ninety-four patients with cerebral infarction and 103 controls were analyzed. Plasma levels of VWF antigen (VWF: Ag), VWF ristocetin cofactor activity (VWF: Rcof), and VWF collagen binding activity (VWF: CB) were measured by enzyme-linked immunosorbent assay (ELISA). The ADAMTS13 activity (ADAMTS13) was measured with FRETS-VWF73. The relationship between plasma levels and ratios of VWF and ADAMTS13 and the occurrence of cerebral infarction were analyzed.

RESULTS

Patients with cerebral infarction displayed higher VWF: Ag and VWF: Rcof levels and lower ADAMTS13, VWF: CB/VWF: Ag, ADAMTS13/VWF: Ag, and ADAMTS13/VWF: Rcof levels compared to controls (P < .01). The highest quartiles of VWF: Ag (odds ratio [OR] = 5.11, 95% confidence interval [CI], 1.49-17.50) and VWF: Rcof (OR = 5.04, 95% CI, 1.62-15.66) and the lowest quartiles of VWF: CB/VWF: Ag (OR = 5.91, 95% CI, 1.95-17.93), ADAMTS13/VWF: Ag (OR = 9.11, 95% CI, 2.49-33.33), and ADAMTS13/VWF: Rcof (OR = 3.73, 95% CI, 1.39-10.03) are associated with cerebral infarction.

CONCLUSIONS

An association was found between reduced levels of VWF: CB/VWF: Ag, ADAMTS13/VWF: Ag, and ADAMTS13/VWF: Rcof ratios and cerebral infarction. Our data suggest that increased levels of VWF and reduced levels of ADAMTS13 activity may contribute to the pathogenesis of cerebral infarction.

Nucleic acid aptamer-mediated drug delivery for targeted cancer therapy

Aptamers are emerging as promising therapeutic agents and recognition elements. In particular, cell-SELEX (systematic evolution of ligands by exponential enrichment) allows in vitro selection of aptamers selective to whole cells without prior knowledge of the molecular signatures on the cell surface. The advantage of aptamers is their high affinitiy and binding specificity towards the target. This Minireview focuses on single-stranded (ss) oligonucleotide (DNA or RNA)-based aptamers as cancer therapeutics/theranostics. Specifically, aptamer-nanomaterial conjugates, aptamer-drug conjugates, targeted phototherapy and targeted biotherapy are covered in detail. In reviewing the literature, the potential of aptamers as delivery systems for therapeutic and imaging applications in cancer is clear, however, major challenges remain to be resolved, such as the poorly understood pharmacokinetics, toxicity and off-target effects, before they can be fully exploited in a clinical setting.

Development of aptamer oligonucleotides as anticoagulants and antithrombotics for cardiovascular diseases: current status

Aptamers are short DNA/RNA oligonucleotides selected by a process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX) based on affinity for target molecules. Since aptamers have several advantages over monoclonal antibodies, such as high specificity and affinity, flexible modification and stability, and lack of toxicity and immunogenicity, they are promising novel diagnostic and therapeutic agents. In this review, we will describe the development of aptamers against thrombin, von Willebrand factor (vWF), factor IX, and factor XII as potential anticoagulants or antithrombotics for cardiovascular diseases, especially those that have entered clinical trials.

Targeting von Willebrand factor as a novel anti-platelet therapy; application of ARC1779, an Anti-vWF aptamer, against thrombotic risk

Excessive activation of platelets is a causative factor for thrombotic diseases such as acute coronary syndrome or stroke, and various anti-platelet drugs were developed. Aspirin and clopidogrel have been used as gold standards for anti-platelet therapies, however, their clinical limitations including bleeding problem have increased the demand driving development of novel anti-platelet drugs with new targets. Among several activating pathways leading to platelet aggregation, the interaction between von Willebrand factor (vWF) and glycoprotein Ib, which mainly occurs under high shear stress in arterioles, is recently suggested to be a new promising target. The anti-thrombotic efficacy of anti-vWF agents, such as ARC1779, has been proved in several preclinical and clinical studies. Here, we will discuss the potential benefits of targeting vWF as a novel antiplatelet therapy, providing an insight into the role of vWF in increased thrombotic risk.

A comparative study of bovine and porcine pericardium to highlight their potential advantages to manufacture percutaneous cardiovascular implants

Rationale:

Prosthetic heart valves designed to be implanted percutaneously must be loaded within delivery catheters whose diameter can be as low as 18 F (6 mm). This mandatory crimping of the devices may result in deleterious damages to the tissues used for valve manufacturing. As bovine and porcine pericardial tissue are currently given preference because of their excellent availability and traceability, a preliminary comparative study was undertaken to highlight their potential advantages.

Materials and methods:

Bovine and pericardium patches were compared morphologically (light microscopy, scanning electron microscopy and transmission electron microscopy). The acute thrombogenicity of both materials was measured in term of platelet uptake and observed by scanning electron microscopy, porcine intact and injured arteries being used as controls. The pericardium specimens were also subjected to uniaxial tensile tests to compare their respective mechanical characteristics.

Results:

Both pericardiums showed a layered architecture of collagen bundles presenting some interstitial cells. They displayed wavy crimps typical of an unloaded collagenous tissue. The collagen bundles were not bound together and the fibrils were parallel with characteristic periodicity patterns of cross striations. The mesothelial cells found in vivo on the serous surface were no longer present due to tissue processing, but the adjacent structure was far more compacted when compared to the fibrous side. The fibrinocollagenous surfaces were found to be more thrombogenic for both bovine and porcine tissues and the serous side of the porcine pericardium retained more platelets when compared to the bovine samples, making the acute thrombogenicity more important in the porcine pericardium.

Conclusion:

Both bovine and porcine pericardium used in cardiovascular implantology can be selected to manufacture percutaneous heart valves. The selection of one pericardium preferably to the other should deserve additional testing regarding the innocuousness of crimping when loaded in delivery catheters and the long-term durability after percutaneous deployment.

Aptamers as therapeutics in cardiovascular diseases

With many advantages over other therapeutic agents such as monoclonal antibodies, aptamers have recently emerged as a novel and powerful class of ligands with excellent potential for diagnostic and therapeutic applications. Typically generated through Systematic Evolution of Ligands by EXponential enrichment (SELEX), aptamers have been selected against a wide range of targets such as proteins, phospholipids, sugars, nucleic acids, as well as whole cells. DNA/RNA aptamers are single-stranded DNA/RNA oligonucleotides (with a molecular weight of 5-40 kDa) that can fold into well-defined 3D structures and bind to their target molecules with high affinity and specificity. A number of strategies have been adopted to synthesize aptamers with enhanced in vitro/in vivo stability, aiming at potential therapeutic/diagnostic applications in the clinic. In cardiovascular diseases, aptamers can be developed into therapeutic agents as anti-thrombotics, anti-coagulants, among others. This review focuses on aptamers that were selected against various molecular targets involved in cardiovascular diseases: von Willebrand factor (vWF), thrombin, factor IX, phospholamban, P-selectin, platelet-derived growth factor, integrin α(v)β(3), CXCL10, vasopressin, among others. With continued effort in the development of aptamer-based therapeutics, aptamers will find their niches in cardiovascular diseases and significantly impact clinical patient management.