Background-Abundant data indicate that overexpression of apolipoprotein A-I (apoA-I) in mice inhibits atherosclerosis.One mechanism is believed to be promotion of reverse cholesterol transport, but no direct proof of this concept exists. We developed a novel approach to trace reverse transport of labeled cholesterol specifically from macrophages to the liver and feces in vivo and have applied this approach to investigate the ability of apoA-I overexpression to promote macrophage-specific reverse cholesterol transport. Method and Results-J774 macrophages were loaded with cholesterol by incubation with acetylated LDL, labeled with 3 H-cholesterol, and then injected intraperitoneally into mice. Plasma and feces were collected at 24 hours and 48 hours, when mice were exsanguinated, tissues were harvested, and all were analyzed for tracer counts. 3 H-cholesterol was found in the plasma, liver, and feces. For apoA-I overexpression, mice were injected intravenously with apoA-I adenovirus (10 11 particles per animal) 3 days before labeled macrophages were injected. ApoA-I overexpression led to significantly higher 3 H-cholesterol in plasma, liver, and feces. The amount of 3 H-tracer in the liver was 35% higher (PϽ0.05) and the 3 H-tracer excreted into feces over 48 hours was 63% higher (PϽ0.05) in apoA-I-expressing mice than in control mice. Conclusion-Injection

Intraplaque release of inflammatory cytokines from macrophages is implicated in atherogenesis by inducing the proliferation and migration of media smooth muscle cells (SMCs). PCSK9 is present and released by SMCs within the atherosclerotic plaque but its function is still unknown. In the present study, we tested the hypothesis that PCSK9 could elicit a pro-inflammatory effect on macrophages. THP-1-derived macrophages and human primary macrophages were exposed to different concentrations (0.250 ÷ 2.5 µg/ml) of human recombinant PCSK9 (hPCSK9). After 24 h incubation with 2.5 µg/ml PCSK9, a significant induction of IL-1β, IL-6, TNF-α, CXCL2, and MCP1 mRNA, were observed in both cell types. Co-culture of THP-1 macrophages with HepG2 overexpressing hPCSK9 also showed the induction of TNF-α (2.4 ± 0.5 fold) and IL-1β (8.6 ± 1.8 fold) mRNA in macrophages. The effect of hPCSK9 on TNF-α mRNA in murine LDLR−/− bone marrow macrophages (BMM) was significantly impaired as compared to wild-type BMM (4.3 ± 1.6 fold vs 31.1 ± 6.1 fold for LDLR−/− and LDLR+/+, respectively). Finally, a positive correlation between PCSK9 and TNF-α plasma levels of healthy adult subjects (males 533, females 537) was observed (B = 8.73, 95%CI 7.54 ÷ 9.93, p < 0.001). Taken together, the present study provides evidence of a pro-inflammatory action of PCSK9 on macrophages, mainly dependent by the LDLR.

Several studies have demonstrated that polyphenol-enriched diets may have beneficial effects against the development of degenerative diseases, including atherosclerosis and disorders affecting the central nervous system. This activity has been associated not only with antioxidant and anti-inflammatory properties, but also with additional mechanisms, such as the modulation of lipid metabolism and gut microbiota function. However, long-term studies on humans provided controversial results, making the prediction of polyphenol impact on health uncertain. The aim of this review is to provide an overview and critical analysis of the literature related to the effects of the principal dietary polyphenols on cardiovascular and neurodegenerative disorders. We critically considered and meta-analyzed randomized controlled clinical trials involving subjects taking polyphenol-based supplements. Although some polyphenols might improve specific markers of cardiovascular risk and cognitive status, many inconsistent data are present in literature. Therefore, definitive recommendations for the use of these compounds in the prevention of cardiovascular disease and cognitive decline are currently not applicable. Once pivotal aspects for the definition of polyphenol bioactivity, such as the characterization of pharmacokinetics and safety, are addressed, it will be possible to have a clear picture of the realistic potential of polyphenols for disease prevention.

Objective-ATP-binding cassette transporter A1 (ABCA1) mediates the efflux of lipids from cells to lipid-poor apolipoproteins. In this article, we characterize the effect of probucol on cellular ABCA1-mediated lipid efflux. Methods and Results-Probucol inhibited cholesterol efflux up to 80% in J774 macrophages expressing ABCA1. In Fu5AH hepatoma cells that contain scavenger receptor class B, type I, but not functional ABCA1, we observed no effect of probucol on cholesterol efflux. Probucol inhibited cholesterol efflux from normal human skin fibroblasts but not from fibroblasts from a Tangier patient. Fluorescent confocal microscopy and biotinylation assay demonstrated that in J774 cells probucol impaired the translocation of ABCA1 from intracellular compartments to the plasma membrane. Probucol also inhibited the formation of an ABCA1-linked cholesterol oxidase sensitive plasma membrane domain. Consistent with the inhibitory effect on ABCA1 translocation to the plasma membrane, probucol reduced cell surface-specific Key Words: probucol Ⅲ lipid efflux Ⅲ ABCA1 Ⅲ macrophages Ⅲ fibroblasts P robucol is a lipid-lowering drug that has been extensively investigated since its introduction in the early 1970s. 1 Among its most dramatic effects is the ability to promote the regression of cutaneous and tendinous xanthoma, and this effect appears to be independent of its cholesterol-lowering effect. 1,2 However, probucol also significantly reduces plasma high-density lipoproteins (HDLs). These facts have made this drug very controversial. It has been reported that probucol treatment induced a more rapid progression of atherosclerotic lesions 3 in apolipoprotein E (apoE) knockout mice. In contrast, a recent study demonstrated that probucol treatment of scavenger receptor class B type I (SR-BI)/apoE double knockout mice prevents the dramatic early coronary heart disease and death that is a characteristic of these animals. 4 Just as the data on probucol effects in vivo are contradictory, so too are the results from a number of experiments that have been conducted to study the action of probucol on cholesterol metabolism in vitro. Yamamoto et al 5 measured the effect of probucol on the change in cholesterol mass on incubation of THP-1 macrophages with HDLs and observed a significant reduction consistent with a probucol-mediated increase in the net efflux of cholesterol. A similar result was obtained by Goldberg and Mendez 6 using human skin fibroblasts. In contrast, a subsequent investigation failed to observe any probucol stimulation in the efflux of cholesterol from a number of cell types. 7 It has been demonstrated that specific cell surface proteins play an important role in mediating the flux of cholesterol between cells and extracellular acceptors (for a review see Yancey et al 8 ). SR-BI facilitates the selective uptake of HDL cholesteryl ester (CE) and enhances the bidirectional flux of free cholesterol (FC) between cells and HDLs. 9 ATP-binding cassette AI (ABCA1) has been shown to bind lipid-free or lipid-poor apoprotei...