Docosahexaenoic fatty acid nanoencapsulated with Anti-PECAM-1 as strategy to increase atherosclerotic plaque stability / Ácido graxo docosahexaenoico nanoencapsulado com anti-PECAM-1 como uma estratégia para aumentar a estabilidade de placas ateroscleróticas

Cardiovascular diseases (CVDs) are the main cause of mortality worldwide, being the ischemic heart disease responsible for 85% of deaths. Atherosclerosis is a chronic inflammation of the arteries that underlies ischemic forms of CVD and involves the innate and adaptive immune systems, from initial fatty streak formation to atherosclerotic plaque ruptures, which defines the beginning and end stages of disease, respectively. Recent research on the reduction of systemic inflammation in order to treat CVD is controversial, since results show that this reduced inflammation can also increase patient susceptibility to general infection. Therefore, new tissue-targeting strategies are necessary. Docosahexaenoic fatty acid (DHA) is a natural bioactive precursor of pro-resolving oxylipins that can reduce inflammation. Based on these factors, the objective of this study was to develop a nanocapsule containing algae oil as a DHA source and apply anti-PECAM-1 on its surface to drive it to the inflamed endothelium. Initially, a surface-functionalized metal-complex multi-wall nanocapsule containing algae oil in its nucleus (MLNC-DHA-a1) was developed. This nanocapsules presented a mean diameter of 163 ± 5 nm, was spherical in shape, showed 94.80% conjugation efficiency using 200 µg/mL of anti-PECAM-1 on the surface, and did not show significant toxicity toward HUVECs at concentrations from 0.14 to 2.90x1011 nanocapsules/mL. The nanocapsules were also stable for 2 h, sufficient time to allow for clinical applications. In cell viability assays, concentrations of 0.14 to 1.40x1011 nanocapsules/mL did not significantly affect the viability of immortalized murine macrophages (RAW 264.7) and U-937 cells after 24, 48, and 72 h of treatment. Finally, macrophages were incubated with 0.75x1011 MLNC-DHA-a1 nanocapsules/mL for 4 h and showed a significant uptake, observed using dark-field hyperspectral microscopy (CytoViva®). Once inside murine macrophages (RAW 264.7), MLNC-DHA-a1 nanocapsules promoted a strong increase in M2 phenotype polarization compared to non-treated control cells. Our results suggest that DHA-enriched algae oil, as part of a lipid core nanocapsules, does not reduce cell viability and improves macrophage phenotype, making it a promising potential therapy for controlling chronic inflammation and healing or stabilizing atherosclerotic plaques

As doenças cardiovasculares (DCVs) são a principal causa de mortalidade no mundo, sendo os eventos isquêmicos responsáveis por 85% das mortes. A aterosclerose é uma inflamação crônica das artérias associada aos eventos isquêmicos das DCVs, na qual o sistema imunológico inato e adaptativo estão envolvidos desde a formação inicial das estrias gordurosas até a ruptura das placas ateroscleróticas. Pesquisas recentes direcionadas à redução da inflamação sistêmica têm mostrado resultados controversos, pois essa abordagem pode aumentar a susceptibilidade do paciente a infecções. Nesse sentido, novas estratégias direcionadas ao tecido lesionado são necessárias. No que se refere a medicamentos anti-inflamatórios ou suplementos alimentares, o ácido docosaexaenóico (DHA) tem sido relatado como um precursor natural de oxilipinas pró- resolutivas. Baseado nesse contexto, o objetivo deste estudo foi desenvolver nanocápsulas contendo óleo de alga como fonte de DHA e vetorizar essas nanopartículas com o anticorpo antiPECAM-1 em sua superfície, visando direcioná-las ao endotélio inflamado. Inicialmente, a nanocápsula multiparede metal-complexa funcionalizada contendo óleo de alga em seu núcleo (MLNC-DHA-a1) foi desenvolvida, apresentando um diâmetro médio de 163 ± 5 nm, formato esférico, onde a eficiência de conjugação do anti-PECAM-1 (200 µg/mL) foi de 94,80% sem toxicidade significativa em HUVECs nas concentrações de 1.14 a 2.9 x 1011 nanocápsulas/mL. As nanocápsulas apresentaram uma estabilidade de 2h, o que representa tempo suficiente para a sua aplicação clínica. A seguir, ensaios de viabilidade celular foram realizados em outras linhagens de células para avaliar a toxicidade das nanocápsulas. As concentrações de 0.14 a 1.40 x 1011 de nanocápsulas/mL não afetaram significativamente a viabilidade celular de macrófagos murinos imortalizados (RAW 264.7) e U-937 após 24, 48 e 72 h de tratamento. Por fim, os macrófagos (RAW 264.7) foram incubados com 0.75 x 1011 MLNC-DHA-a1/mL durante 4 h e apresentam uma captação significativa das nanocápsulas, observada por microscopia hiperespectral de campo escuro (CytoViva®). Uma vez captadas pelos macrófagos murinos imortalizados (RAW 264.7), as nanoformulações MLNC-DHA-a1 promoveram um forte aumento da polarização do fenótipo M2 em comparação com as células controle não tratadas. Nossos resultados sugerem que o óleo de alga rico em DHA presente no núcleo lipídico das nanocápsulas, não reduziu a viabilidade celular e estimulou uma maior polarização de macrófagos para o tipo M2, sendo assim uma terapia potencial para controlar a inflamação crônica e cicatrizar ou estabilizar placas ateroscleróticas

Relationship between Neutrophil-to-Lymphocyte Ratio and Plaque Components in Patients with Coronary Artery Disease: Virtual Histology Intravascular Ultrasound Analysis

The aim of this study was to evaluate the relation between neutrophil-to-lymphocyte ratio (NLR) and plaque components assessed by virtual histology-intravascular ultrasound in 399 coronary artery disease (CAD) patients with 471 coronary lesions. We classified the lesions into two groups according to the NLR on admission {low NLR group (NLR2.73 [n=101])}. By volumetric analysis, total atheroma and the absolute necrotic core (NC) volumes were significantly greater in high NLR group (249.9+/-149.7 microL vs. 192.5+/-127.7 microL, P=0.001, and 32.7+/-26.8 microL vs. 22.8+/-19.4 microL, P=0.001, respectively) and thin-cap fibroatheroma (TCFA) was observed more frequently in high NLR group (33% vs. 18%, P=0.001). ST segment elevation myocardial infarction (odds ratio [OR], 2.159; 95% CI, 1.000-4.660, P=0.050) and NLR>2.73 (OR, 1.848; 95% CI, 1.016-3.360, P=0.044) and total atheroma volume (OR, 1.003; 95% CI, 1.001-1.004, P=0.004) were the independent predictors of TCFA. CAD patients with high NLR had more vulnerable plaque components (greater NC-containing plaques) than those with low NLR.

CD36, a scavenger receptor implicated in atherosclerosis

CD36 is a membrane glycoprotein that is present on various types of cells, including monocytes, macrophages, microvascular endothelial cells, adipocytes and platelets. Macrophage CD36 participates in atherosclerotic arterial lesion formation through its interaction with oxidized low-density lipoprotein (oxLDL), which triggers signaling cascades for inflammatory responses. CD36 functions in oxLDL uptake and foam cell formation, which is the initial critical stage of atherosclerosis. In addition, oxLDL via CD36 inhibits macrophage migration, which may be a macrophage-trapping mechanism in atherosclerotic lesions. The role of CD36 was examined in in vitro studies and in vivo experiments, which investigated various functions of CD36 in atherosclerosis and revealed that CD36 deficiency reduces atherosclerotic lesion formation. Platelet CD36 also promotes atherosclerotic inflammatory processes and is involved in thrombus formation after atherosclerotic plaque rupture. Because CD36 is an essential component of atherosclerosis, defining the function of CD36 and its corresponding signaling pathway may lead to a new treatment strategy for atherosclerosis.