Re-Visiting Antioxidant Therapy in Murine Advanced Atherosclerosis with Brussels Chicory, a Typical Vegetable in Mediterranean Diets

Brussels chicory, a typical vegetable in Mediterranean diets, has been recently reported to stabilize advanced atherosclerotic plaques in the brachiocephalic artery of apoE-deficient (Apoe-/-) mice. Herein, we investigated whether Brussels chicory can stabilize advanced plaques in the aorta via improving oxidative stress. Thirty week old Apoe-/- mice were fed the AIN-93G diet or supplemented with 0.5% freeze-dried Brussels chicory for twenty weeks. Aortic plaque size and stability, aortic relaxation, monocyte adhesion to aortic endothelium, free radicals, and enzymatic and non-enzymatic factors involved in free radical production and elimination in aorta and serum were measured. Brussels chicory consumption did not alter aortic plaque size, however, it stabilized aortic plaques, promoted aortic relaxation, and also inhibited monocyte adhesion to aortic endothelium. Moreover, this administration reduced oxidized LDL (ox-LDL) and 4-hydroxynonenal (4-HNE) content in aortic plaques, associated with inhibited aortic NADPH oxidase (NOX) and uncoupled endothelial nitric oxide synthase (eNOS)-mediated free radical production. However, Brussels chicory consumption did not appreciably alter aortic and serum superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities, aortic glutathione (GSH), as well as serum non-enzymatic antioxidants, such as bilirubin, uric acid, and GSH. Collectively, improved oxidative stress might contribute to the atheroprotective effect of Brussels chicory, supporting the prospect of the antioxidant therapy in advanced atherosclerosis progression.

Brussels Chicory Stabilizes Unstable Atherosclerotic Plaques and Reshapes the Gut Microbiota in Apoe-/- Mice

BACKGROUND

Adherence to a Mediterranean dietary pattern can protect against atherosclerosis in part by reducing intestinal permeability and gut microbial LPS production. Brussels chicory, a typical Mediterranean vegetable, has been shown to inhibit the formation of early-stage atherosclerosis in mice.

OBJECTIVES

We evaluated whether Brussels chicory affects advanced atherosclerosis progression, intestinal permeability, and gut microbial LPS production.

METHODS

Thirty-week-old male apoE-deficient mice with unstable atherosclerotic plaques in the brachiocephalic artery were fed the AIN-93G diet alone (control) or supplemented with 0.5% freeze-dried Brussels chicory for 20 wk. Plaque volume and features of plaque stability, plaque macrophage polarization, fecal and serum LPS concentrations, serum lipid profiles and inflammation-related cytokines, and gut microbial profiles were measured.

RESULTS

Compared with the control treatment, Brussels chicory consumption did not significantly change plaque volume and serum lipid profiles. However, it increased plaque stability (P < 0.05), as evidenced by reduced necrotic core size (42.3%), and increased fibrous cap thickness (55.0%) and collagen content (68.4%). Moreover, Brussels chicory consumption reduced intestinal permeability (56.3%), fecal and serum LPS concentrations (52.2% and 39.4%), serum IL1β and TNFα (52.0% and 33.8%), promoted plaque macrophage polarization towards the M2-like phenotype, and altered gut microbial composition, the latter indicated by increased relative abundance of certain members of the Ruminococcaceae family, such as Ruminiclostridium_9, Ruminiclostridium_5, and Intestinimonas (P < 0.05). Spearman correlation analyses further showed that these bacterial genera were significantly correlated with intestinal permeability, fecal and serum LPS, serum proinflammatory cytokines, and several features of plaque stability.

CONCLUSIONS

Brussels chicory might help stabilize atherosclerotic plaques in mice by reducing intestinal permeability and gut microbial LPS production. This study provides a promising approach to slow the progression of atherosclerosis.