Combined treatment of hydroxytyrosol with carbon monoxide-releasing molecule-2 prevents TNF α-induced vascular endothelial cell dysfunction through NO production with subsequent NFκB inactivation

Antioxidants Hydroxytyrosol and Thioredoxin-Mimetic Peptide CB3 Protect Irradiated Normal Tissue Cells

Reducing side effects in non-cancerous tissue is a key aim of modern radiotherapy. Here, we assessed whether the use of the antioxidants hydroxytyrosol (HT) and thioredoxin-mimetic peptide CB3 (TMP) attenuated radiation-induced normal tissue toxicity in vitro. We used primary human umbilical vein endothelial cells (HUVECs) and human epidermal keratinocytes (HaCaT) as normal tissue models. Cells were treated with HT and TMP 24 h or immediately prior to irradiation. Reactive oxygen species (ROS) were assessed via luminescent- and fluorescence-based assays, migration was investigated using digital holographic microscopy, and clonogenic survival was quantified by colony formation assays. Angiogenesis and wound healing were evaluated via time-dependent microscopy. Secreted cytokines were validated in quantitative polymerase chain reaction (qPCR) studies. Treatment with HT or TMP was well tolerated by cells. The application of either antioxidant before irradiation resulted in reduced ROS formation and a distinct decrease in cytokines compared to similarly irradiated, but otherwise untreated, controls. Antioxidant treatment also increased post-radiogenic migration and angiogenesis while accelerating wound healing. HT or TMP treatment immediately before radiotherapy increased clonogenic survival after radiotherapy, while treatment 24 h before radiotherapy enhanced baseline proliferation. Both antioxidants may decrease radiation-induced normal tissue toxicity and deserve further pre-clinical investigation.

Carbon monoxide therapy: a promising strategy for cancer

Cancer is one of the acute life-threatening diseases endangering the whole of humanity. The treatment modalities for cancer are various. However, in most cases, a single treatment choice provides multiple side effects, poor targeting, and ineffective treatment. In recent years, the physiological regulatory function of carbon monoxide (CO) in the cancer process has been reported gradually, and CO-related nano-drugs have been explored. It shows better application prospects in cancer treatment and provides new ideas for treatment. The present review introduces the pathophysiological role of CO. The recent advances in cancer therapy, such as CO-mediated gas therapy, combined application of CO chemotherapy, photodynamic therapy (PDT), photothermal therapy (PTT), and immunotherapy, are described. Current challenges and future developments in CO-based treatment are also discussed. This review provides comprehensive information on recent advances in CO therapy and also some valuable guidance for promoting the progress of gas therapy nanomedicine.

Effects of Hydroxytyrosol in Endothelial Functioning: A Comprehensive Review

Pharmacologists have been emphasizing and applying plant and herbal-based treatments in vascular diseases for decades now. Olives, for example, are a traditional symbol of the Mediterranean diet. Hydroxytyrosol is an olive-derived compound known for its antioxidant and cardioprotective effects. Acknowledging the merit of antioxidants in maintaining endothelial function warrants the application of hydroxytyrosol in endothelial dysfunction salvage and recovery. Endothelial dysfunction (ED) is an impairment of endothelial cells that adversely affects vascular homeostasis. Disturbance in endothelial functioning is a known precursor for atherosclerosis and, subsequently, coronary and peripheral artery disease. However, the effects of hydroxytyrosol on endothelial functioning were not extensively studied, limiting its value either as a nutraceutical supplement or in clinical trials. The action of hydroxytyrosol in endothelial functioning at a cellular and molecular level is gathered and summarized in this review. The favorable effects of hydroxytyrosol in the improvement of endothelial functioning from in vitro and in vivo studies were scrutinized. We conclude that hydroxytyrosol is capable to counteract oxidative stress, inflammation, vascular aging, and arterial stiffness; thus, it is beneficial to preserve endothelial function both in vitro and in vivo. Although not specifically for endothelial dysfunction, hydroxytyrosol safety and efficacy had been demonstrated via in vivo and clinical trials for cardiovascular-related studies.

Effects of Oleuropein and Hydroxytyrosol on Inflammatory Mediators: Consequences on Inflammaging

Aging is associated with a low-grade, systemic inflammatory state defined as "inflammaging", ruled by the loss of proper regulation of the immune system leading to the accumulation of pro-inflammatory mediators. Such a condition is closely connected to an increased risk of developing chronic diseases. A number of studies demonstrate that olive oil phenolic compound oleuropein and its derivative hydroxytyrosol contribute to modulating tissue inflammation and oxidative stress, thus becoming attractive potential candidates to be used in the context of nutraceutical interventions, in order to ameliorate systemic inflammation in aging subjects. In this review, we aim to summarize the available data about the anti-inflammatory properties of oleuropein and hydroxytyrosol, discussing them in the light of molecular pathways involved in the synthesis and release of inflammatory mediators in inflammaging.

Molecular Action of Hydroxytyrosol in Attenuation of Intimal Hyperplasia: A Scoping Review

Objective: Hydroxytyrosol (HT), a polyphenol of olive plant is well known for its antioxidant, anti-inflammatory and anti-atherogenic properties. The aim of this systematic search is to highlight the scientific evidence evaluating molecular efficiency of HT in halting the progression of intimal hyperplasia (IH), which is a clinical condition arises from endothelial inflammation.

Methods: A systematic search was performed through PubMed, Web of Science and Scopus, based on pre-set keywords which are Hydroxytyrosol OR 3,4-dihydroxyphenylethanol, AND Intimal hyperplasia OR Neointimal hyperplasia OR Endothelial OR Smooth muscles. Eighteen in vitro and three in vitro and in vivo studies were selected based on a pre-set inclusion and exclusion criteria.

Results: Based on evidence gathered, HT was found to upregulate PI3K/AKT/mTOR pathways and supresses inflammatory factors and mediators such as IL-1β, IL-6, E-selectin, P-selectin, VCAM-1, and ICAM-1 in endothelial vascularization and functioning. Two studies revealed HT disrupted vascular smooth muscle cells (SMC) cell cycle by dephosphorylating ERK1/2 and AKT pathways. Therefore, HT was proven to promote endothelization and inhibit vascular SMCs migration thus hampering IH development. However, none of these studies described the effect of HT collectively in both vascular endothelial cells (EC) and SMCs in IH ex vivo model.

Conclusions: Evidence from this concise review provides an insight on HT regulation of molecular pathways in reendothelization and inhibition of VSMCs migration. Henceforth, we propose effect of HT on IH prevention could be further elucidated through in vivo and ex vivo model.

Bazedoxifene Plays a Protective Role against Inflammatory Injury of Endothelial Cells by Targeting CD40

The inflammatory response and oxidative stress play key roles in the formation and development of atherosclerosis. Bazedoxifene is a new IL6/GP130 inhibitor recommended by the FDA for clinical use as a selective estrogen receptor modulator. However, its role in cardiovascular diseases has been poorly studied. In our study, we explored the mechanism of bazedoxifene's protective effect against inflammatory injury of vascular endothelial cells (VECs) stimulated by TNF-α. Various methods were used to verify the effect of bazedoxifene on VECs, including a cell viability assay, a wound healing assay, immunofluorescence staining, and western blotting. Our results showed that TNF-α could induce inflammatory damage to VECs, which manifested as upregulated expression of CD40, increased production of ROS, enhanced adhesion of THP-1 cells to VECs, and impaired viability and migration of VECs, while bazedoxifene could significantly reduce the endothelial damage caused by TNF-α. In addition, we found that an siRNA targeting CD40 dramatically alleviated the VEC damage induced by TNF-α. Therefore, we explored the potential relationship between bazedoxifene and CD40. Our data suggest that bazedoxifene has a protective effect against VEC damage induced by TNF-α and that its underlying mechanism may be related to the regulation of CD40.

3-Hydroxytyrosol Promotes Angiogenesis In Vitro by Stimulating Endothelial Cell Migration

Cardiovascular diseases, followed by strokes, represent the leading cause of mortality worldwide. Despite its success in preventing cardiovascular diseases, the therapeutic potential of 3-Hydroxytyrosol (HT) for treating ischemic diseases is yet to be investigated in detail, especially with regard to ischemic heart disease, which is a major challenge for humans. We assessed that low concentrations (1-5 µM) of HT, generally achieved after the ingestion of olive oil, stimulate endothelial cells migration and angiogenesis in an in vitro model. At early time points (1-6 h), HT induces the expression of different proteins such as proto-oncogene tyrosine-protein kinase Src (Src), rho-associated protein kinase (ROCK) and matrix metalloproteinase-2 (MMP-2) protein influencing cell adhesion, cytoskeletal dynamics and cell migration. We observed that at the same time, HT induces prominent vascular formation in the tube formation assay, accompanied by an increase in the expression of the vascular endothelial growth factor receptor (VEGF-R2) and PI3K-Akt-eNOS protein pathways, which are recognized for their central role in angiogenesis. Therefore, in addition to the proven capability of HT to regulate reactive oxygen species (ROS) levels, through both direct scavenging properties and indirect antioxidant efficacy, our results revealed that HT promotes angiogenesis, arguing in favor of great pharma-nutritional potential in ischemic injuries.

Is Extra Virgin Olive Oil an Ally for Women's and Men's Cardiovascular Health?

Noncommunicable diseases are long-lasting and slowly progressive and are the leading causes of death and disability. They include cardiovascular diseases (CVD) and diabetes mellitus (DM) that are rising worldwide, with CVD being the leading cause of death in developed countries. Thus, there is a need to find new preventive and therapeutic approaches. Polyphenols seem to have cardioprotective properties; among them, polyphenols and/or minor polar compounds of extra virgin olive oil (EVOO) are attracting special interest. In consideration of numerous sex differences present in CVD and DM, in this narrative review, we applied "gender glasses." Globally, it emerges that olive oil and its derivatives exert some anti-inflammatory and antioxidant effects, modulate glucose metabolism, and ameliorate endothelial dysfunction. However, as in prescription drugs, also in this case there is an important gender bias because the majority of the preclinical studies are performed on male animals, and the sex of donors of cells is not often known; thus a sex/gender bias characterizes preclinical research. There are numerous clinical studies that seem to suggest the benefits of EVOO and its derivatives in CVD; however, these studies have numerous limitations, presenting also a considerable heterogeneity across the interventions. Among limitations, one of the most relevant in the era of personalized medicine, is the non-attention versus women that are few and, also when they are enrolled, sex analysis is lacking. Therefore, in our opinion, it is time to perform more long, extensive and lessheterogeneous trials enrolling both women and men.

Resveratrol and its dimers ε-viniferin and δ-viniferin in red wine protect vascular endothelial cells by a similar mechanism with different potency and efficacy

Red wine compounds have been reported to reduce the rate of atherosclerosis by inducing nitric oxide (NO) production and antioxidant enzyme expression in vascular endothelial cells (VECs). The present study compared the effects of the three red wine compounds resveratrol and its dimers, ε-viniferin and δ-viniferin, on VECs function for the first time. Both 5 μM ε-viniferin and δ-viniferin, but not 5 μM resveratrol, significantly stimulated wound repair of VECs. Increased levels of wound repair induced by 10 and 20 μM ε-viniferin were significantly higher than those stimulated by 10 and 20 μM resveratrol, respectively. These stimulatory effects of the three compounds were suppressed by the NO synthase inhibitor L-NAME. When VECs were exposed to each compound, endothelial NO synthase was activated and the expression of sirtuin 1 (SIRT1) and HO-1 was induced. Addition of the SIRT1 and HO-1 inhibitors EX527 and ZnPPiX, respectively, suppressed wound repair stimulated by the three compounds, demonstrating that SIRT1 and HO-1 are involved in these wound repair processes. Furthermore, each compound induced the suppression of H₂ O₂ -dependent reduction of cell viability as well as the expression of the antioxidant enzyme catalase. These data suggest that not only resveratrol, but also its dimers, ε-viniferin and δ-viniferin, may be effective in preventing atherosclerosis by a similar molecular mechanism with different potency and efficacy.

Antioxidant Effects of a Hydroxytyrosol-Based Pharmaceutical Formulation on Body Composition, Metabolic State, and Gene Expression: A Randomized Double-Blinded, Placebo-Controlled Crossover Trial

Hydroxytyrosol (HT) plays a significant role in cardiovascular disease (CVD) protection, and its metabolites are able to protect from the endothelial dysfunction commonly present in atherosclerosis. This randomized double-blinded, placebo-controlled crossover trial determined the effect in healthy volunteers of two gastroresistant capsules containing 15 mg/day of HT, for a 3-week period (HTT). Evaluation of nutritional status, serum metabolites, oxidative stress biomarkers, and gene expression of 9 genes related to oxidative stress, inflammation, and CVDs was performed. Oxidation biomarkers like thiol group (p = 0.001), total antioxidant status (TAS) (p = 0.001), superoxide dismutase 1 (SOD1) (2^-ΔΔCt = 3.7), and plasma concentration of HT (2.83 μg·mL^-1) were significantly increased, while nitrite (p = 0.001), nitrate (p = 0.001), and malondialdehyde (MDA) (p = 0.02) were drastically reduced after HTT. A significant reduction of body fat mass percentage (p = 0.01), suprailiac skinfold (p = 0.01), and weight (p = 0.04; Δ% = -0.46%) was observed after HTT. This study shows that regular intake of 15 mg/day of HT changed body composition parameters and modulated the antioxidant profile and the expression of inflammation and oxidative stress-related genes. However, it is advisable to personalize HT doses in order to exert its health benefits in CVD prevention and protection of LDL-C particles from oxidative damage. This trial is registered with ClinicalTrials.gov NCT01890070.

Hydroxytyrosol in the Prevention of the Metabolic Syndrome and Related Disorders

Virgin olive oil (VOO) constitutes the main source of fat in the Mediterranean diet. VOO is rich in oleic acid, displaying health-promoting properties, but also contains minor bioactive components, especially phenolic compounds. Hydroxytyrosol (HT), the main polyphenol of olive oil, has been reported to be the most bioactive component. This review aims to compile the results of clinical, animal and cell culture studies evaluating the effects of HT on the features of Metabolic Syndrome (MetS) (body weight/adiposity, dyslipidemia, hypertension, and hyperglycemia/insulin resistance) and associated complications (oxidative stress and inflammation). HT was able to improve the lipid profile, glycaemia, and insulin sensitivity, and counteract oxidative and inflammatory processes. Experimental studies identified multiple molecular targets for HT conferring its beneficial effect on health in spite of its low bioavailability. However, rodent experiments and clinical trials with pure HT at biologically relevant concentrations are still lacking. Moreover, the roles of intestine and its gut microbiota have not been elucidated.

Role of Hydroxytyrosol-dependent Regulation of HO-1 Expression in Promoting Wound Healing of Vascular Endothelial Cells via Nrf2 De Novo Synthesis and Stabilization

Hydroxytyrosol (HT), an olive plant (Olea europaea L.) polyphenol, has proven atheroprotective effects. We previously demonstrated that heme oxygenase-1 (HO-1) is involved in the HT dependent prevention of dysfunction induced by oxidative stress in vascular endothelial cells (VECs). Here, we further investigated the signaling pathway of HT-dependent HO-1 expression in VECs. HT dose- and time-dependently increased HO-1 mRNA and protein levels through the PI3K/Akt and ERK1/2 pathways. Cycloheximide and actinomycin D inhibited both increases, suggesting that HT-triggered HO-1 induction is transcriptionally regulated and that de novo protein synthesis is necessary for this HT effect. HT stimulated nuclear accumulation of nuclear factor E2-related factor 2 (Nrf2). This Nrf2 accumulation was blocked by actinomycin D and cycloheximide whereas HT in combination with the 26S proteasome inhibitor MG132 enhanced the accumulation. HT also extended the half-life of Nrf2 proteins by decelerating its turnover. Moreover, HO-1 inhibitor, ZnppIX and CO scavenger, hemoglobin impaired HT-dependent wound healing while CORM-2, a CO generator, accelerated wound closure. Together, these data demonstrate that HT upregulates HO-1 expression by stimulating the nuclear accumulation and stabilization of Nrf2, leading to the wound repair of VECs crucial in the prevention of atherosclerosis.

Nitric oxide and carbon monoxide antagonize TGF-β through ligand-independent internalization of TβR1/ALK5

Transforming growth factor (TGF)-β plays a central role in vascular homeostasis and in the pathology of vascular disease. There is a growing appreciation for the role of nitric oxide (NO) and carbon monoxide (CO) as highly diffusible, bioactive signaling molecules in the vasculature. We hypothesized that both NO and CO increase endocytosis of TGF-β receptor type 1 (TβR1) in vascular smooth muscle cells (VSMCs) through activation of dynamin-2, shielding cells from the effects of circulating TGF-β. In this study, primary cultures of VSMCs from Sprague-Dawley rats were treated with NO-releasing molecule 3 (a NO chemical donor), CO-releasing molecule 2 (a CO chemical donor), or control. NO and CO stimulated dynamin-2 activation in VSMCs. NO and CO promoted time- and dose-dependent endocytosis of TβR1. By decreasing TβR1 surface expression through this dynamin-2-dependent process, NO and CO diminished the effects of TGF-β on VSMCs. These findings help explain an important mechanism by which NO and CO signal in the vasculature by decreasing surface expression of TβR1 and the cellular response to TGF-β.