Low-density lipoprotein promotes microvascular thrombosis by enhancing von Willebrand factor self-association

Treatment with APAC, a dual antiplatelet anticoagulant heparin proteoglycan mimetic, limits early collar-induced carotid atherosclerotic plaque development in Apoe-/- mice

BACKGROUND AND AIMS

Mast cell-derived heparin proteoglycans (HEP-PG) can be mimicked by bioconjugates carrying antithrombotic and anti-inflammatory properties. The dual antiplatelet and anticoagulant (APAC) construct administered, either locally or intravenously (i.v.), targets activated endothelium, its adhesion molecules, and subendothelial matrix proteins, all relevant to atherogenesis. We hypothesized that APAC influences cellular interactions in atherosclerotic lesion development and studied APAC treatment during the initiation and progression of experimental atherosclerosis.

METHODS

Male western-type diet-fed Apoe-/- mice were equipped with perivascular carotid artery collars to induce local atherosclerosis. In this model, mRNA expression of adhesion molecules including ICAM-1, VCAM-1, P-Selectin, and Platelet Factor 4 (PF4) are upregulated upon lesion development. From day 1 (prevention) or from 2.5 weeks after lesion initiation (treatment), mice were administered 0.2 mg/kg APAC i.v. or control vehicle three times weekly for 2.5 weeks. At week 5 after collar placement, mice were sacrificed, and lesion morphology was microscopically assessed.

RESULTS

APAC treatment did not affect body weight or plasma total cholesterol levels during the experiments. In the prevention setting, APAC reduced carotid artery plaque size and volume by over 50 %, aligning with decreased plaque macrophage area and collagen content. During the treatment setting, APAC reduced macrophage accumulation and necrotic core content, and improved markers of plaque stability.

CONCLUSIONS

APAC effectively reduced early atherosclerotic lesion development and improved markers of plaque inflammation in advanced atherosclerosis. Thus, APAC may have potential to alleviate the progression of atherosclerosis.

Revisiting the full blood count: Circulating blood cells and their role in coagulation

There has been an expansion in our understanding of the multifaceted roles of circulating blood cells in regulating haemostasis and contributing to thrombosis. Notably, there is greater recognition of the interplay between coagulation with inflammation and innate immune activation and the contribution of leucocytes. The full blood count (FBC) is a time-honoured test in medicine; however, its components are often viewed in isolation and without consideration of their haemostatic and thrombotic potential. Here, we review how the individual components of the FBC, that is, haemoglobin, platelets and leucocytes, engage with the haemostatic system and focus on both their quantitative and qualitative attributes. We also explore how this information can be harnessed into better management of people with multiple long-term conditions because of their higher risk of adverse clinical events.

The Pleiotropic Effects of Lipid-Modifying Interventions: Exploring Traditional and Emerging Hypolipidemic Therapies

Atherosclerotic cardiovascular disease poses a significant global health issue, with dyslipidemia standing out as a major risk factor. In recent decades, lipid-lowering therapies have evolved significantly, with statins emerging as the cornerstone treatment. These interventions play a crucial role in both primary and secondary prevention by effectively reducing cardiovascular risk through lipid profile enhancements. Beyond their primary lipid-lowering effects, extensive research indicates that these therapies exhibit pleiotropic actions, offering additional health benefits. These include anti-inflammatory properties, improvements in vascular health and glucose metabolism, and potential implications in cancer management. While statins and ezetimibe have been extensively studied, newer lipid-lowering agents also demonstrate similar pleiotropic effects, even in the absence of direct cardiovascular benefits. This narrative review explores the diverse pleiotropic properties of lipid-modifying therapies, emphasizing their non-lipid effects that contribute to reducing cardiovascular burden and exploring emerging benefits for non-cardiovascular conditions. Mechanistic insights into these actions are discussed alongside their potential therapeutic implications.

Bidirectional causality between the levels of blood lipids and endometriosis: a two-sample mendelian randomization study

BACKGROUND

Observational studies have found a correlation between the levels of blood lipids and the development and progression of endometriosis (EM). However, the causality and direction of this correlation is unclear. This study aimed to examine the bidirectional connection between lipid profiles and the risk of EM using publicly available genome-wide association study (GWAS) summary statistics.

METHODS

Eligible exposure variables such as levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were selected using a two-sample Mendelian randomization (MR) analysis method following a series of quality control procedures. Data on EM were obtained from the publicly available Finnish database of European patients. Inverse variance weighted (IVW), MR Egger, weighted median, and weighted mode methods were used to analyze the causal relationship between lipid exposure and EM, exclude confounders, perform sensitivity analyses, and assess the stability of the results. Reverse MR analyses were performed with EM as exposure and lipid results as study outcomes.

RESULTS

IVW analysis results identified HDL as a protective factor for EM, while TG was shown to be a risk factor for EM. Subgroup analyses based on the site of the EM lesion identified HDL as a protective factor for EM of the uterus, while TG was identified a risk factor for the EM of the fallopian tube, ovary, and pelvic peritoneum. Reverse analysis did not reveal any effect of EM on the levels of lipids.

CONCLUSION

Blood lipids, such as HDL and TG, may play an important role in the development and progression of EM. However, EM does not lead to dyslipidemia.

Removal of endothelial surface-associated von villebrand factor suppresses accelerate datherosclerosis after myocardial infarction

BACKGROUND

Thromboinflammation involving platelet adhesion to endothelial surface-associated von Willebrand factor (VWF) has been implicated in the accelerated progression of non-culprit plaques after MI. The aim of this study was to use arterial endothelial molecular imaging to mechanistically evaluate endothelial-associated VWF as a therapeutic target for reducing remote plaque activation after myocardial infarction (MI).

METHODS

Hyperlipidemic mice deficient for the low-density lipoprotein receptor and Apobec-1 underwent closed-chest MI and were treated chronically with either: (i) recombinant ADAMTS13 which is responsible for proteolytic removal of VWF from the endothelial surface, (ii) N-acetylcysteine (NAC) which removes VWF by disulfide bond reduction, (iii) function-blocking anti-factor XI (FXI) antibody, or (iv) no therapy. Non-ischemic controls were also studied. At day 3 and 21, ultrasound molecular imaging was performed with probes targeted to endothelial-associated VWF A1-domain, platelet GPIbα, P-selectin and vascular cell adhesion molecule-1 (VCAM-1) at lesion-prone sites of the aorta. Histology was performed at day 21.

RESULTS

Aortic signal for P-selectin, VCAM-1, VWF, and platelet-GPIbα were all increased several-fold (p < 0.01) in post-MI mice versus sham-treated animals at day 3 and 21. Treatment with NAC and ADAMTS13 significantly attenuated the post-MI increase for all four molecular targets by > 50% (p < 0.05 vs. non-treated at day 3 and 21). On aortic root histology, mice undergoing MI versus controls had 2-4 fold greater plaque size and macrophage content (p < 0.05), approximately 20-fold greater platelet adhesion (p < 0.05), and increased staining for markers of platelet transforming growth factor-β1 signaling. Accelerated plaque growth and inflammatory activation was almost entirely prevented by ADAMTS13 and NAC. Inhibition of FXI had no significant effect on molecular imaging signal or plaque morphology.

CONCLUSIONS

Plaque inflammatory activation in remote arteries after MI is strongly influenced by VWF-mediated platelet adhesion to the endothelium. These findings support investigation into new secondary preventive therapies for reducing non-culprit artery events after MI.

Clot or Not? Reviewing the Reciprocal Regulation Between Lipids and Blood Clotting

Both hyperlipidemia and thrombosis contribute to the risks of atherosclerotic cardiovascular diseases, which are the leading cause of death and reduced quality of life in survivors worldwide. The accumulation of lipid-rich plaques on arterial walls eventually leads to the rupture or erosion of vulnerable lesions, triggering excessive blood clotting and leading to adverse thrombotic events. Lipoproteins are highly dynamic particles that circulate in blood, carry insoluble lipids, and are associated with proteins, many of which are involved in blood clotting. A growing body of evidence suggests a reciprocal regulatory relationship between blood clotting and lipid metabolism. In this review article, we summarize the observations that lipoproteins and lipids impact the hemostatic system, and the clotting-related proteins influence lipid metabolism. We also highlight the gaps that need to be filled in this area of research.