Red wine metabolites modulate NF-κB, activator protein-1 and cAMP response element-binding proteins in human endothelial cells

Anthocyanins and Vascular Health: A Matter of Metabolites

Anthocyanins are a subgroup of flavonoid polyphenols previously investigated for improving cardiovascular health and preventing the development of endothelial dysfunction. However, their poor bioavailability raises the question of whether the observed biological activity is due to their metabolites. Phenolic metabolites can reach higher plasma concentrations and can persist in the circulation for periods much longer than their original anthocyanin form; therefore, the biological activity and health promoting effects of anthocyanins may differ from their metabolites. To address this, recent studies have facilitated different cell models, in vivo studies and explored physiologically relevant concentrations to better understand their mechanisms of action. The criteria were chosen based on previous reports demonstrating that anthocyanins can improve endothelial function via modulation of the Akt-endothelial nitric oxide synthase pathway and transcription factors Nrf2 and NF-κB, which made it critical to assess the phenolic metabolites' modes of action via these pathways. This review demonstrates how phenolic metabolites differ in bioactivity from their precursor anthocyanin, demonstrating improved endothelial function in response to inflammatory mediators at concentrations that are tolerated in vivo. The review highlights the crucial need for further studies to focus on improving the bioavailability of metabolites in isolation and explore the effect of metabolites in mixtures.

The French paradox three decades later: Role of inflammation and thrombosis

Although, three decades have pasted from the introduction of "French Paradox", is still an issue for debate. Epidemiology supports the J-shaped relationship between wine consumption and vascular events as well as cardiovascular mortality with a maximum protection at 21 g of alcohol consumption in the form of wine per day. Nevertheless, the aforementioned studies have used an observational design that raises concerns about potential confounding. Randomized clinical studies may provide data to end the controversy and in parallel with in vitro experiments to elucidate the mechanisms by which wine affects cardiovascular disease. In this concept, this review aims to address the presence of bioactive wine micro constituents, their potential mechanisms of action and also to summarize the cardio-protective effects of wine intake based on clinical trials. The role of wine micro-constituents in inflammation and haemostasis is discussed in detail.

The beneficial and deleterious role of dietary polyphenols on chronic degenerative diseases by regulating gene expression

Dietary polyphenols, a natural component in many kinds of foods such as fruits and vegetables, play essential roles in a wide range of plant functions. Importantly, the discovery of the functions of polyphenols including anti-oxidant, anti-carcinogenic and anti-inflammatory has been appealing to researchers' attentions. Dietary polyphenols have shown protective effects on chronic degenerative diseases (CDD) such as cardiovascular diseases, cancers, and neurodegenerative diseases by regulating gene expression. Dietary polyphenols also affect the composition and activity of gut microbiota, in reverse, gut microbiota influences the bioavailability and physiological activity of dietary polyphenols. However, not all kinds of dietary polyphenols are beneficial for human health. The potential deleterious effects of several dietary polyphenols have been reported by inducing DNA damage and gene mutants. This review summarizes the potential therapeutic effects of dietary polyphenols on chronic degeneration diseases, the polyphenols-gut microbiota interactions, and the potential dangers of individual dietary polyphenols on human health.

Signatures of anthocyanin metabolites identified in humans inhibit biomarkers of vascular inflammation in human endothelial cells

SCOPE

The physiological relevance of contemporary cell culture studies is often perplexing, given the use of unmetabolized phytochemicals at supraphysiological concentrations. We investigated the activity of physiologically relevant anthocyanin metabolite signatures, derived from a previous pharmacokinetics study of 500 mg 13 C5 -cyanidin-3-glucoside in eight healthy participants, on soluble vascular adhesion molecule-1 (VCAM-1) and interleukin-6 (IL-6) in human endothelial cells.

METHODS AND RESULTS

Signatures of peak metabolites (previously identified at 1, 6, and 24 h post-bolus) were reproduced using pure standards and effects were investigated across concentrations ten-fold lower and higher than observed mean (<5 μM) serum levels. Tumor necrosis factor-α (TNF-α)-stimulated VCAM-1 was reduced in response to all treatments, with maximal effects observed for the 6 and 24 h profiles. Profiles tested at ten-fold below mean serum concentrations (0.19-0.44 μM) remained active. IL-6 was reduced in response to 1, 6, and 24 h profiles, with maximal effects observed for 6 h and 24 h profiles at concentrations above 2 μM. Protein responses were reflected by reductions in VCAM-1 and IL-6 mRNA, however there was no effect on phosphorylated NFκB-p65 expression.

CONCLUSION

Signatures of anthocyanin metabolites following dietary consumption reduce VCAM-1 and IL-6 production, providing evidence of physiologically relevant biological activity.

Tocotrienols induce endoplasmic reticulum stress and apoptosis in cervical cancer cells

BACKGROUND

We have previously reported that γ- and δ-tocotrienols (γ- and δ-T3) induce gene expression and apoptosis in human breast cancer cells (MDA-MB-231 and MCF-7). This effect is mediated, at least in part, by a specific binding and activation of the estrogen receptor-β (ERβ). Transcriptomic data obtained within our previous studies, interrogated by different bioinformatic tools, suggested the existence of an alternative pathway, activated by specific T3 forms and leading to apoptosis, also in tumor cells not expressing ER. In order to confirm this hypothesis, we conducted a study in HeLa cells, a line of human cervical cancer cells void of any canonical ER form.

RESULTS

Cells were synchronized by starvation and treated either with a T3-rich fraction from palm oil (10-20 μg/ml) or with purified α-, γ-, and δ-T3 (5-20 μg/ml). α-tocopherol (TOC) was utilized as a negative control. Apoptosis, accompanied by a significant expression of caspase 8, caspase 10, and caspase 12 was observed at 12 h from treatments. The interrogation of data obtained from transcriptomic platforms (NuGO Affymetrix Human Genechip NuGO_Hs1a520180), further confirmed by RT-PCR, suggested that the administration of γ- and δ-T3 associates with Ca²⁺ release. Data interrogation were confirmed in living cells; in fact, Ca-dependent signals were observed followed by the expression and activation of IRE-1α and of other molecules involved in the unfolded protein response, the core pathway coping with endoplasmic reticulum stress in eukaryotic cells, finally leading to apoptosis.

CONCLUSIONS

Our study demonstrates that γ- and δ-T3 induce apoptosis also in tumor cells lacking of ERβ by triggering signals originating from endoplasmic reticulum stress. Our observations suggest that tocotrienols could have a significant role in tumor cell physiology and a possible therapeutic potential.

Isoxanthohumol modulates angiogenesis and inflammation via vascular endothelial growth factor receptor, tumor necrosis factor alpha and nuclear factor kappa B pathways

Angiogenesis and inflammation are becoming distinguished players in the pathogenesis of many heterogeneous diseases, such as diabetes, cardiovascular disease, and cancer. Therefore, it is crucial to study new compounds that are able to modulate these events. Isoxanthohumol (IXN) is a polyphenol with antioxidant, anti-inflammatory, and antiangiogenic properties. The aim of this study was to evaluate the effects of IXN on blood vessel proliferation and maturation and describe underlying molecular mechanisms in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). Angiogenic profile of IXN was analyzed by retinal angiogenesis at different time points. IXN modulation of angiogenic and inflammatory signaling pathways was evaluated by Western blotting on EC and VSMC cultures. IXN inhibited by 20% sprouting angiogenesis and decreased vascular coverage by mural cells up to 39%. IXN of 10 µM also decreased inflammatory signals, namely tumor necrosis factor alpha (TNF-α) (26 and 40%) and factor nuclear kappa B (24 and 42%) in human aortic smooth muscle cells (HASMCs) and human umbilical vein endothelial cells (HUVECs). Angiogenic regulators, including vascular endothelial growth factor receptor 2 (HUVEC, 55%), angiopoietins 1 (HUVEC, 39%; HASMC, 35%), angiopoietin 2 (HUVEC, 38%), and Tie2 (HUVEC, 56%) were also inhibited by 10 µM of IXN treatments. Akt activation was reduced by 47% in HUVEC-treated cells and Erk activation was also reduced by 52 and 69% upon IXN treatment of HUVEC and HASMC. IXN seems to regulate in vivo vascular proliferation and stabilization and the EC-VSMC-inflammatory crosstalk, leaving this molecule as an interesting nutritional player for angiogenesis and inflammation-related diseases.

Anthocyanins protect human endothelial cells from mild hyperoxia damage through modulation of Nrf2 pathway

The detrimental effects of high oxygen supplementation have been widely reported. Conversely, few is known about the effects of exposure to mild hyperoxic conditions, an interesting issue since the use of oxygen-enriched mixture is now increasingly used in clinical practice and especially for professional and recreational reasons. Our study investigated if in vitro exposure of human umbilical vein endothelial cells (HUVECs) to moderate hyperoxia (O2 32 %) induces cellular alterations, measured as changes in cell signaling pathways. Furthermore, by means of an ex vivo experimental model where human volunteers were used as bioreactors, we studied whether anthocyanin metabolites are able to protect HUVECs against mild hyperoxia-induced damage. We observed that the cytotoxic effect of mild hyperoxia came along with a significant decrease in nuclear accumulation of the transcription factor Nrf2, as well as in the expression of Nrf2-regulated antioxidant and cytoprotective genes. Furthermore, under normoxic conditions, anthocyanin metabolites appeared able to activate the Nrf2 pathway, through the involvement of specific kinases (ERK1/2); this adaptive effect may explain the protective effect observed in mild hyperoxia-exposed HUVECs following anthocyanin pretreatment. This study confirms that dietary anthocyanins and/or their metabolites can protect endothelial cells against mild hyperoxia-induced alterations acting as cell signaling modulators.

Cyanidin-3-O-glucoside protection against TNF-α-induced endothelial dysfunction: involvement of nuclear factor-κB signaling

Oxidative stress and inflammation are considered to play a pivotal role in vascular endothelial dysfunction by triggering activation of transcription factors, such as NF-κB, functionally dependent on cellular redox status. The anthocyanin cyanidin-3-O-glucoside (C3G), as well as other phytochemicals recognized as potent antioxidants and free radical scavengers, may act as modulators of gene regulation and signal transduction pathways. This study demonstrates that C3G is able to protect human endothelial cells against alterations induced by TNF-α, including the activation of NF-κB, increased gene expression of adhesion molecules, leukocyte adhesion to endothelium, and intracellular accumulation of H2O2 and lipid peroxidation byproducts. These observations contribute to provide a conceptual background for the understanding of the mechanisms underlying the role of C3G, as well as other dietary plant polyphenols, in the prevention of diseases associated with inflammation and oxidative stress, including atherosclerosis.

Microbial and host cells acquire enhanced oxidant-scavenging abilities by binding polyphenols

The dilemma whether supplementations of dietary antioxidants might prevent the adverse consequences of oxidative stress, the inadequacy of the analytical methods employed to quantify oxidant scavenging ability (OSA) levels in whole blood and the distribution and fate of polyphenols and their metabolites in various body compartments following oral consumption are discussed. While none-metabolized polyphenols might exert their antioxidant effects mainly in the oral cavity, metabolized polyphenols might be beneficial in the gastrointestinal tract to counteract the toxicity of oxidants and also of the sequelae of inflammatory processes. Although only micromolar amounts of polyphenols and their metabolites eventually reach the blood circulation, these may nevertheless still be highly effective as scavengers of reactive oxygen and nitrogen species because of their ability to synergize with plasma low molecular-weight antioxidants and with albumin. Polyphenols can avidly bind to surfaces of microorganisms and of blood cells to markedly enhance their OSA, therefore the routine quantifications of antioxidant levels conducted in clinical settings should always use catalase-rich whole blood but not as customary, plasma alone. In addition to their antioxidant and metal chelating properties, polyphenols may also act as signaling agents capable of affecting metabolic, inflammatory, autoimmune, carcinogenic and aging processes.