Background and aimsMast 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 in atherogenesis. We hypothesized that APAC influences cellular interactions in atherosclerotic lesion development and studied APAC treatment during the initiation and progression of experimental atherosclerosis. MethodsMale 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. ResultsAPAC 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. ConclusionsAPAC 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.