Athera (Sweden)

Introduction: Phosphorylcholine (PC), one of the main oxLDL epitopes, is an important pro-inflammatory damage associated molecular pattern. Epidemiologic data show that natural anti-PC IgM protect against cardiovascular disease. Within atherosclerotic lesions, inflammation and angiogenesis are linked via VEGFA secreting CD163 + macrophages. PC antibodies are recognized for their anti-inflammatory properties, the effect of PC antibodies on intraplaque angiogenesis (IPA) and intraplaque hemorrhage (IPH) is yet unknown. Hypothesis: Newly developed IgG1 PC antibody (PCmAb) inhibits lesion development via IPA and IPH reduction in murine vein graft atherosclerosis. Methods: Hypercholesterolemic male ApoE3*Leiden mice received a (donor) caval vein interposition in the carotid artery and weekly ip injections of (5mg/kg) PCmAb (n=11) or vehicle (n=12) until sacrifice at day 28. Vein graft morphometry and lesion composition including IPA and IPH were evaluated via immunohistochemistry. In vitro PCmAb effects were investigated in Hemoglobin (Hb):Haptoglobin(Hp)-cultured THP-1 macrophages and HUVECs. Results: PCmAb significantly decreased vein graft media area (13%), intima lesion (25%), and increased lumen area with 53% compared to vehicle. PCmAb improved lesion stability by increasing collagen content (18%) and decreased macrophages presence (31%). VCAM-1 and ICAM-1 expression in the vessel wall were also reduced (29%, 36%). PCmAb resulted in 23% decreased CD163 + macrophages content in vein grafts whereas CD163 expression was reduced in Hb:Hp stimulated macrophages. PCmAb significantly reduced neovessel density (34%) and significant reduced EC proliferation and migration with and without oxLDL stimulation. Moreover, PCmAb enhanced maturation of intraplaque angiogenic vessels by increasing neovessel pericyte coverage in vivo (31%). Together, this resulted in a 62%reduction of IPH. Conclusions: PCmAb effectively inhibits murine atherosclerotic lesion formation. PCmAb reduces IPA and IPH by decreased neovessel density and macrophages influx via reduced expression of VCAM-1 and ICAM-1, and increased neovessel maturation in vein graft atherosclerosis. PCmAb holds promise as a new therapeutic approach for plaque stability.

Phosphorylcholine is a pro‐inflammatory epitope exposed on apoptotic cells, and phosphorylcholine monoclonal immunoglobulin (Ig)G antibodies (PC‐mAb) have anti‐inflammatory properties. In this study, we hypothesize that PC‐mAb treatment reduces adverse cardiac remodelling and infarct size (IS) following unreperfused transmural myocardial infarction (MI). Unreperfused MI was induced by permanent ligation of the left anterior descending (LAD) coronary artery in hypercholesterolaemic APOE*3‐Leiden mice. Three weeks following MI, cardiac magnetic resonance (CMR) imaging showed a reduced LV end‐diastolic volume (EDV) by 21% and IS by 31% upon PC‐mAb treatment as compared to the vehicle control group. In addition, the LV fibrous content was decreased by 27% and LV wall thickness was better preserved by 47% as determined by histological analysis. Two days following MI, CCL2 concentrations, assessed by use of ELISA, were decreased by 81% and circulating monocytes by 64% as assessed by use of FACS analysis. Additionally, local leucocyte infiltration determined by immunohistological analysis showed a 62% decrease after three weeks. In conclusion, the local and systemic inflammatory responses are limited by PC‐mAb treatment resulting in restricted adverse cardiac remodelling and IS following unreperfused MI. This indicates that PC‐mAb holds promise as a therapeutic agent following MI limiting adverse cardiac remodelling.

Purpose: Antibodies against phosphorylcholine (αPC) are known to have anti-inflammatory properties and ameliorate atherosclerosis development. Low IgM αPC levels are associated with development of cardiovascular diseases. Therefore, we investigated the effect of a monoclonal antibody against phosphorylcholine (PC-mAb) on left ventricular (LV) function and remodeling 3 weeks after myocardial ischemia-reperfusion (MI-R) injury in hypercholesterolemic APOE*3-Leiden mice. Methods: We investigated the effects of PC-mAb application (10mg/kg every 3rd day) on LV remodeling after MI-R injury in hypercholesterolemic APOE*3-Leiden mice compared with a vehicle-control and sham-operated group. After 45 minutes of ischemia by occlusion of the left anterior descending coronary artery permanent reperfusion was induced. LV function was assessed 2 and 20 days after MI-R using 7T magnetic resonance imaging (MRI) including delayed-enhancement MRI using gadolinium (Gd)-DPTA contrast agent. Histological analysis of infarct size (IS) and LV wall thickness were performed by Sirius Red staining 21 days post-reperfusion. Results: After 20 days, PC-mAb reduced LV end-diastolic volume (EDV; 33.7±1.4μl vs. 44.3±2.3μl, P<0.001) and end-systolic volume (ESV; 15.5±0.9μl vs. 26.0±2.2μl, P<0.001) compared with vehicle. LV volumes in the PC-mAb and sham operated group (EDV 30.3±1.2μl, P=0.59, and ESV 11.1±1.0μl, P=0.19 respectively) were not significantly different. LV ejection fraction (EF) decrease was observed in both PC-mAb (54.1±1.8%, P=0.028) and vehicle (41.8±2.9%, P<0.001) groups compared with sham mice (63.8±2.1%) but PC-mAb showed a better preserved EF compared with vehicle (P=0.002). After 2 days, delayed-enhancement MRI showed no difference in IS between the PC-mAb and vehicle groups (28.3±1.4% vs. 30.4±2.0%, P=0.40). However, IS 21 days after MI-R was reduced in the PC-mAb compared with the vehicle group (13.7±1.4% vs. 19.0±1.8%, P=0.048) accompanied with a trend towards increased LV wall thickness of the border zone (1.11±0.07mm vs. 0.99±0.10mm, P=0.066) and infarcted area (0.79±0.09mm vs. 0.67±0.12mm, P=0.12). Conclusion: PC-mAb treatment restricts infarct expansion, left ventricular remodeling, and preserves cardiac function after myocardial ischemia-reperfusion injury in hypercholesterolemic APOE*3-Leiden mice.