Background: Oxidative stress plays an essential role in the pathogenesis of type 2 diabetes. Anthocyanin, a natural antioxidant, has been reported to

Context: Intermittent fasting (IF) is an effective strategy to improve cardiometabolic health. Objective: The objective of this work is to examine the effects of IF on cardiometabolic risk factors and the gut microbiota in patients with metabolic syndrome (MS). Design and Setting: A randomized clinical trial was conducted at a community health service center. Patients: Participants included adults with MS, age 30 to 50 years. Intervention: Intervention consisted of 8 weeks of “2-day” modified IF. Main Outcome Measure: Cardiometabolic risk factors including body composition, oxidative stress, inflammatory cytokines, and endothelial function were assessed at baseline and at 8 weeks. The diversity, composition, and functional pathways of the gut microbiota, as well as circulating gut-derived metabolites, were measured. Results: Thirty-nine patients with MS were included: 21 in the IF group and 18 in the control group. On fasting days, participants in the IF group reduced 69% of their calorie intake compared to nonfasting days. The 8-week IF significantly reduced fat mass, ameliorated oxidative stress, modulated inflammatory cytokines, and improved vasodilatory parameters. Furthermore, IF induced significant changes in gut microbiota communities, increased the production of short-chain fatty acids, and decreased the circulating levels of lipopolysaccharides. The gut microbiota alteration attributed to the IF was significantly associated with cardiovascular risk factors and resulted in distinct genetic shifts of carbohydrate metabolism in the gut community. Conclusion: IF induces a significant alteration of the gut microbial community and functional pathways in a manner closely associated with the mitigation of cardiometabolic risk factors. The study provides potential mechanistic insights into the prevention of adverse outcomes associated with MS.

Objective—: Considerable evidence supports the early involvement of monocyte/macrophage recruitment to activated endothelial cells by leukocyte adhesion molecules during atherogenesis. AMP-activated protein kinase (AMPK) is highly expressed in vascular endothelial cells, but its impact on monocyte adhesion and the related mechanisms are not fully understood. The present study was designed to evaluate the impact of and gain mechanistic insight into the signaling coupling AMPK function to the antiinflammatory response. Methods and Results—: 5-Aminoimidazole-4-carboxamide-1-β- d -ribonucleotide (AICAR) treatment or overexpression of constitutively active AMPK markedly reduced human monocytic human acute monocytic leukemia cell line-1 cell adhesion and the expression of vascular cell adhesion molecule-1 in tumor necrosis factor-α–activated human aortic endothelial cells. Furthermore, AICAR or constitutively active AMPK overexpression strongly inhibited the histone acetyltransferase activity of the transcriptional coactivator p300 by phosphorylation of Ser89, which in turn decreased tumor necrosis factor-α-activated p300-mediated acetylation of nuclear factor-κB p65 on Lys221 and reduced the DNA binding activity of nuclear factor-κB by inhibiting its recruitment to its target gene promoters. AMPK phosphorylates the transcriptional coactivator p300 via the atypical protein kinase Cι/λ. Conclusion—: Our findings demonstrate that transcriptional coactivator p300 phosphorylation at Ser89 by AMPK is critical for the therapeutic effect of AMPK and may be a potential target for pharmaceutical intervention in inflammatory diseases such as atherosclerosis.

Adiponectin is an adipose tissue-secreted adipokine with beneficial effects on the cardiovascular system. In this study, we evaluated a potential role for adiponectin in the protective effects of anthocyanin on diabetes-related endothelial dysfunction. We treated db/db mice on a normal diet with anthocyanin cyanidin-3-O-β-glucoside (C3G; 2 g/kg diet) for 8 wk. Endothelium-dependent and -independent relaxations of the aorta were then evaluated. Adiponectin expression and secretion were also measured. C3G treatment restores endothelium-dependent relaxation of the aorta in db/db mice, whereas diabetic mice treated with an anti-adiponectin antibody do not respond. C3G treatment induces adiponectin expression and secretion in cultured 3T3 adipocytes through transcription factor forkhead box O1 (Foxo1). Silencing Foxo1 expression prevented C3G-stimulated induction of adiponectin expression. In contrast, overexpression of Foxo1-ADA promoted adiponectin expression in adipocytes. C3G activates Foxo1 by increasing its deacetylation via silent mating type information regulation 2 homolog 1 (Sirt1). Furthermore, purified anthocyanin supplementation significantly improved flow-mediated dilation (FMD) and increased serum adiponectin concentrations in patients with type 2 diabetes. Changes in adiponectin concentrations positively correlated with FMD in the anthocyanin group. Mechanistically, adiponectin activates cAMP-PKA-eNOS signaling pathways in human aortic endothelial cells, increasing endothelial nitric oxide bioavailability. These results demonstrate that adipocyte-derived adiponectin is required for anthocyanin C3G-mediated improvement of endothelial function in diabetes.

Increasing evidence suggests that adenosine monophosphate-activated protein kinase (AMPK) exerts protective effects for cardiovascular diseases apart from the regulation of energy homeostasis. However, the role of AMPK and its underlying mechanism on macrophage foam cell formation are poorly understood. In this study, we sought to investigate the potential effects of AMPK in modulating cholesterol deposition by using murine macrophage-derived foam cells. Incubation with 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) markedly attenuated the cholesterol ester accumulation in oxidized low density lipoprotein-loaded macrophages. Notably, AICAR treatment significantly increased ATP-binding cassette transporters G1 (Abcg1) mRNA and protein levels without affecting mRNA and protein expression of ABCA1, scavenger receptors, including scavenger receptor-A, CD36, and scavenger receptor-BI (SR-BI), and cholesterol synthesis-related genes. The up-regulation of Abcg1 by AICAR was independent of the liver X receptor/retinoid X receptor pathway but dependent on ERK activation. AICAR elevates Abcg1 expression through a post-transcriptional mechanism that stabilizes the mRNA. Using a heterologous system with luciferase as a reporter, we further identify the Abcg1 mRNA 3′-UTR responsible for the regulatory effect of AICAR. Prevention of ABCG1 expression by small interfering RNA abolished the AICAR-mediated attenuation on foam cell formation. Furthermore, increased ABCG1 expression and reduced lipid accumulation were demonstrated in AICAR-treated macrophages isolated from apolipoprotein E-deficient mice (apoE^−/− mice). AICAR treatment also inhibited atherosclerotic plaque formation in apoE^−/− mice. Our findings elucidate a precise mechanism involved in the prevention of atherogenesis by AMPK.