Differential effects of resveratrol on the dilator responses of femoral arteries, ex vivo.

Resveratrol is a plant-derived phytoalexin with antioxidant, anti-inflammatory and cardio-protective properties and may be a promising therapeutic intervention strategy in cardiovascular disease. Here, we investigated the acute direct effects of trans-resveratrol (RV), on acetylcholine (ACh)-induced and flow-mediated dilation (FMD) of isolated pressurized femoral arteries of young (4-month-old) and old (26-month-old) mice. Vessel exposure to RV enhanced ACh (0.01-1.0 mM)-induced dilation (p < 0.05), but not FMD (@ 5-10 µL⋅min-1) (p < 0.05) in both young and old mice. After RV incubation, acute nitric oxide (NO) production by cultured endothelial cells was increased in response to 0.01 mM ACh, but reduced by flow (5-10 µL⋅min-1; p < 0.05). In isolated femoral arteries from endothelial nitric oxide synthase knockout (eNOS-/-) mice, RV had no overall effect on FMD, but potentiated ACh induced dilation, that was completely abolished by potassium channel blockers, Apamin and Tram 34 (p < 0.01). We demonstrate that the non-metabolised form of RV stimulates ACh-induced dilation via the NO and EDHF pathways, but not FMD by interaction with the cyclo-oxygenase pathway. Our findings have important implications in the use of RV (for both young and aged) under 'normal' non-diseased physiological states.

Tetramethoxystilbene-Loaded Liposomes Restore Reactive-Oxygen-Species-Mediated Attenuation of Dilator Responses in Rat Aortic Vessels Ex vivo.

The methylated analogue of the polyphenol resveratrol (RV), 2,3',4,5'-tetramethoxystilbene (TMS) displays potent antioxidant properties and is an effective cytochrome P450 (CYP) 1B1 inhibitor. The bioavailability of TMS is low. Therefore, the use of liposomes for the encapsulation of TMS is a promising delivery modality for enhanced uptake into tissues. We examined the effect of delivery of TMS in liposomes on the restoration of vasodilator responses of isolated aortic vessels after acute tension elevation ex vivo. Aortic vessels from young male Wistar rats were isolated, and endothelial-dependent (acetylcholine, ACh) and -independent (sodium nitroprusside, SNP) responses assessed. Acute tension elevation (1 h) significantly reduced ACh dilator responses, which were restored following incubation with superoxide dismutase or apocynin (an NADPH oxidase inhibitor). Incubation with TMS-loaded liposomes (mean diameter 157 ± 6 nm; PDI 0.097) significantly improved the attenuated dilator responses following tension elevation, which was sustained over a longer period (4 h) when compared to TMS solution. Endothelial denudation or co-incubation with L-NNA (Nω-nitro-l-arginine; nitric oxide synthase inhibitor) resulted in loss of dilator function. Our findings suggest that TMS-loaded liposomes can restore attenuated endothelial-dependent dilator responses induced by an oxidative environment by reducing NADPH-oxidase-derived ROS and potentiating the release of the vasodilator nitric oxide. TMS-loaded liposomes may be a promising therapeutic strategy to restore vasodilator function in vascular disease.

Small diameter helical vascular scaffolds support endothelial cell survival.

There is an acute clinical need for small-diameter vascular grafts as a treatment option for cardiovascular disease. Here, we used an intelligent design system to recreate the natural structure and hemodynamics of small arteries. Nano-fibrous tubular scaffolds were fabricated from blends of polyvinyl alcohol and gelatin with inner helices to allow a near physiological spiral flow profile, using the electrospinning technique. Human coronary artery endothelial cells (ECs) were seeded on the inner surface and their viability, distribution, gene expression of mechanosensitive and adhesion molecules compared to that in conventional scaffolds, under static and flow conditions. We show significant improvement in cell distribution in helical vs. conventional scaffolds (94% ±â€¯9% vs. 82% ±â€¯7.2%; P < 0.05) with improved responsiveness to shear stress and better ability to withhold physiological pressures. Our helical vascular scaffold provides an improved niche for EC growth and may be attractive as a potential small diameter vascular graft.

Home-Based Rehabilitation With Telemonitoring Guidance for Patients With Coronary Artery Disease (Short-Term Results of the TRiCH Study): Randomized Controlled Trial.

BACKGROUND: Cardiac rehabilitation (CR) is an essential part of contemporary coronary heart disease management. However, patients exiting a center-based CR program have difficulty retaining its benefits. OBJECTIVE: We aimed to evaluate the added benefit of a home-based CR program with telemonitoring guidance on physical fitness in patients with coronary artery disease (CAD) completing a phase II ambulatory CR program and to compare the effectiveness of this program in a prolonged center-based CR intervention by means of a randomized controlled trial. METHODS: Between February 2014 and August 2016, 90 CAD patients (unblinded, mean age 61.2 years, SD 7.6; 80/90, 89.0% males; mean height 1.73 m, SD 0.7; mean weight 82.9 kg, SD 13; mean body mass index 27.5 kg/m2, SD 3.4) who successfully completed a 3-month ambulatory CR program were randomly allocated to one of three groups: home-based (30), center-based (30), or control group (30) on a 1:1:1 basis. Home-based patients received a home-based exercise intervention with telemonitoring guidance consisting of weekly emails or phone calls; center-based patients continued the standard in-hospital CR, and control group patients received the usual care including the advice to remain physically active. All the patients underwent cardiopulmonary exercise testing for assessment of their peak oxygen uptake (VO2 P) at baseline and after a 12-week intervention period. Secondary outcomes included physical activity behavior, anthropometric characteristics, traditional cardiovascular risk factors, and quality of life. RESULTS: Following 12 weeks of intervention, the increase in VO2 P was larger in the center-based (P=.03) and home-based (P=.04) groups than in the control group. In addition, oxygen uptake at the first (P-interaction=.03) and second (P-interaction=.03) ventilatory thresholds increased significantly more in the home-based group than in the center-based group. No significant changes were observed in the secondary outcomes. CONCLUSIONS: Adding a home-based exercise program with telemonitoring guidance following completion of a phase II ambulatory CR program results in further improvement of physical fitness and is equally as effective as prolonging a center-based CR in patients with CAD. TRIAL REGISTRATION: ClinicalTrials.gov NCT02047942; https://clinicaltrials.gov/ct2/show/NCT02047942 (Archived by WebCite at http://www.webcitation.org/70CBkSURj).

Perceived benefits of patient support groups and their format for people with an implantable cardioverter defibrillator.

BACKGROUND: Support groups for people with Implantable Cardioverter Defibrillators (ICDs) are widely used, however, it is not clear what people with ICDs gain from a support group or what format they should take. OBJECTIVES: The aim of the present study is to define the perceived benefit of ICD support groups and develop practical recommendations for group format. METHODS: 14 individuals with ICDs were interviewed using a semi-structured interview guide. Reflexive thematic analysis methods were utilised to code and analyse the transcripts before generating themes. RESULTS: Four themes were defined: confronting mortality, coping through sharing, coping through learning, and providing space. Making connections with other people with ICDs, reassurance, access to information, and advice from health care professionals were important perceived benefits of the support group. CONCLUSION: People with ICDs may have to confront their own mortality and adapt to considerable life changes after implant. The findings from the present study have improved understanding of how support groups are perceived and how ICD indication and group format influence the experience. A blended format of in-person community meetings, online forums, HCP-led education and space for person-person interaction is recommended. Importantly, provision of support should not be time-limited to allow people to access it when it most likely to be of benefit to them.

Altered sensitivity to nitric oxide donors, induced by intravascular infusion of quantum dots, in murine mesenteric arteries.

Quantum dots (QDs) are utilised in imaging diagnostics, tissue engineering and medical therapeutics, however, their influence on vascular function is not ascertained. Here, we examined small mesenteric arterial responses after acute intravascular exposure to QDs. Incubation in mercaptoundecanoic acid (MUA)-coated QDs (at 15 µg/mL) had no influence on endothelial-dependent dilator responses (Acetylcholine; Ach) but led to an attenuated relaxation to the nitric oxide donor, sodium nitroprusside (SNP). Conversely, incubation in POSS-PCU coated QDs (at 15 µg/mL) led to attenuated Ach responses (10(-11)-10(-3)M; n=5, P<0.05), but had no influence on SNP-induced relaxation. At lower concentrations of POSS-PCU coated QDs (5 µg/mL), Ach responses were preserved. We demonstrate that acute exposure to QDs, can attenuate vasodilation but not vasoconstriction, and is dependent on their surface coatings. Our findings have implications in QD use for imaging diagnostics in disease states, where SNP based drugs are used in therapeutic intervention. FROM THE CLINICAL EDITOR: In this paper, the influence of quantum dots on vascular function is investigated---an important aspect to consider with the growing utility of quantum dots in imaging diagnostics, tissue engineering and medical therapeutics.

Benefits of support groups for patients living with implantable cardioverter defibrillators: a mixed-methods systematic review and meta-analysis.

BACKGROUND: Patients with implantable cardioverter defibrillators (ICD) experience anxiety, depression and reduced quality of life (QoL). OBJECTIVES: This mixed-methods systematic review evaluates whether ICD support groups have a beneficial effect on mental well-being. METHODS: Literature searches were carried out in MEDLINE, Embase, CINAHL, PsycINFO and Web of Science. Eligible studies investigated patient-led support groups for ICD patients aged 18 years or older, using any quantitative or qualitative design. The Mixed-Methods Assessment Tool was used to assess quality. Meta-analysis of measures of mental well-being was conducted. Thematic synthesis was used to generate analytic themes from the qualitative data. The data were integrated and presented using the Pillar Integration Process. RESULTS: Ten studies were included in this review. All studies bar one were non-randomised or had a qualitative design and patients had self-selected to attend a support group. Five contributed to the quantitative data synthesis and seven to the qualitative synthesis. Meta-analysis of anxiety and QoL measures showed no significant impact of support groups on mental well-being, but qualitative data showed that patients perceived benefit from attendance through sharing experiences and acceptance of life with an ICD. DISCUSSION: ICD support group attendance improved the patients' perceived well-being. Attendees value the opportunity to share their experiences which helps to accept their new life with an ICD. Future research could consider outcomes such as patient acceptance and the role of healthcare professionals at support groups.

Internal Mammary Arteries as a Model to Demonstrate Restoration of the Impaired Vasodilation in Hypertension, Using Liposomal Delivery of the CYP1B1 Inhibitor, 2,3',4,5'-Tetramethoxystilbene.

A significant number of patients with severe cardiovascular disease, undergoing coronary artery bypass grafting (CABG), present with hypertension. While internal mammary arteries (IMAs) may be a better alternative to vein grafts, their impaired vasodilator function affects their patency. Our objectives were to (1) determine if inhibition of the cytochrome P450 enzyme CYP1B1, using liposome-encapsulated 2,3',4,5'-tetramethoxystilbene (TMS), can potentiate vasodilation of IMAs from CABG patients, and (2) assess mechanisms involved using coronary arteries from normal rats, in an ex vivo model of hypertension. PEGylated liposomes were synthesized and loaded with TMS (mean diameter 141 ± 0.9 nm). Liposomal delivery of TMS improved its bioavailability Compared to TMS solution (0.129 ± 0.02 ng/mL vs. 0.086 ± 0.01 ng/mL at 4 h; p < 0.05). TMS-loaded liposomes alleviated attenuated endothelial-dependent acetylcholine (ACh)-induced dilation in diseased IMAs (@ACh 10−4 M: 56.9 ± 5.1%; n = 8 vs. 12.7 ± 7.8%; n = 6; p < 0.01) for TMS-loaded liposomes vs. blank liposomes, respectively. The alleviation in dilation may be due to the potent inhibition of CYP1B1 by TMS, and subsequent reduction in reactive oxygen species (ROS) moieties and stimulation of nitric oxide synthesis. In isolated rat coronary arteries exposed to a hypertensive environment, TMS-loaded liposomes potentiated nitric oxide and endothelium-derived hyperpolarization pathways via AMPK. Our findings are promising for the future development of TMS-loaded liposomes as a promising therapeutic strategy to enhance TMS bioavailability and potentiate vasodilator function in hypertension, with relevance for early and long-term treatment of CABG patients, via the sustained and localized TMS release within IMAs.

Biocompatibility of amorphous silica nanoparticles: Size and charge effect on vascular function, in vitro.

Synthetic amorphous silica is gaining popularity as the material of choice in the fabrication of nanoparticles for use in imaging diagnostics, medical therapeutics, and tissue engineering because of its biocompatible nature. However, recent evidence suggests that silica nanoparticles (SiNPs) show a concentration- and size-dependent toxic effect that is cell specific. We investigated the direct influence of SiNP uptake on the vasodilator responses of rat aortic vessels, in vitro, using fabricated SiNPs of defined size (97 ± 7.60 and 197 ± 7.50 nm) and charge (positive and nonmodified). Dilator responses to cumulative doses of endothelial-dependent [acetylcholine (Ach); 0.01 µM-1.0 mM] and endothelial-independent (sodium nitroprusside; 0.01-10 µM) agonists were determined before and 30 Min after incubation in SiNPs (at 1.1 × 10(11) nanoparticles/mL). Acute exposure to SiNPs led to their rapid uptake by the lining endothelial cells (as verified by transmission electron microscopy). SiNP uptake had no significant influence on dilator responses, although a greater degree of attenuation was evident after uptake of the 100 nm and positively charged SiNPs (significant at the highest 1.0 mM Ach concentration between positive and nonmodified 200 nm SiNPs; P < 0.05). In summary, our findings suggest that SiNP surface interactions, rather than mass, affect vasodilator function of aortic vessels.

Nanostructured Lipid Carriers Deliver Resveratrol, Restoring Attenuated Dilation in Small Coronary Arteries, via the AMPK Pathway.

Nanostructured lipid carriers (NLCs) are an emerging drug delivery platform for improved drug stability and the bioavailability of antihypertensive drugs and vasoprotective nutraceutical compounds, such as resveratrol (RV). The objective of this study was to ascertain NLCs' potential to deliver RV and restore attenuated dilator function, using an ex vivo model of acute hypertension. Trimyristin-triolein NLCs were synthesized and loaded with RV. The uptake of RV-NLCs by human coronary artery endothelial cells (HCAECs) maintained their viability and reduced both mitochondrial and cytosolic superoxide levels. Acute pressure elevation in isolated coronary arteries significantly attenuated endothelial-dependent dilator responses, which were reversed following incubation in RV-NLCs, superoxide dismutase or apocynin (p < 0.0001). RV-NLCs demonstrated a five-fold increase in potency in comparison to RV solution. At elevated pressure, in the presence of RV-NLCs, incubation with Nω-nitro-l-arginine (L-NNA) or indomethacin resulted in a significant reduction in the restored dilator component (p < 0.0001), whereas apamin and TRAM-34 had no overall effect. Incubation with the adenosine monophosphate-activated protein kinase (AMPK) inhibitor dorsomorphin significantly attenuated dilator responses (p < 0.001), whereas the SIRT-1 inhibitor EX-527 had no effect. RV-NLCs improved the impaired endothelial-dependent dilation of small coronary arteries, following acute pressure elevation, via NO and downstream COX elements, mediated by AMPK. We suggest that RV-NLCs are an effective delivery modality for improved potency and sustained drug release into the vasculature. Our findings have important implications for the future design and implementation of antihypertensive treatment strategies.

Home-based exercise with telemonitoring guidance in patients with coronary artery disease: Does it improve long-term physical fitness?

BACKGROUND: Home-based interventions might facilitate the lifelong uptake of a physically active lifestyle following completion of a supervised phase II exercise-based cardiac rehabilitation. Yet, data on the long-term effectiveness of home-based exercise training on physical activity and exercise capacity are scarce. OBJECTIVE: The purpose of the TeleRehabilitation in Coronary Heart disease (TRiCH) study was to compare the long-term effects of a short home-based phase III exercise programme with telemonitoring guidance to a prolonged centre-based phase III programme in coronary artery disease patients. The primary outcome was exercise capacity. Secondary outcomes included physical activity behaviour, cardiovascular risk profile and health-related quality of life. METHODS: Ninety coronary artery disease patients (80 men) were randomly assigned to 3 months of home-based (30), centre-based (30) or a control group (30) on a 1:1:1 basis after completion of their phase II ambulatory cardiac rehabilitation programme. Outcome measures were assessed at discharge of the phase II programme and after one year. RESULTS: Eighty patients (72 (91%) men; mean age 62.6 years) completed the one-year follow-up measurements. Exercise capacity and secondary outcomes were preserved in all three groups (Ptime > 0.05 for all), irrespective of the intervention (Pinteraction > 0.05 for all). Eighty-five per cent of patients met the international guidelines for physical activity (Ptime < 0.05). No interaction effect was found for physical activity. CONCLUSION: Overall, exercise capacity remained stable during one year following phase II cardiac rehabilitation. Our home-based exercise intervention was as effective as centre-based and did not result in higher levels of exercise capacity and physical activity compared to the other two interventions. TRIAL REGISTRATION: ClinicalTrials.gov NCT02047942. https://clinicaltrials.gov/ct2/show/NCT02047942.

Publisher Correction: On the issue of transparency and reproducibility in nanomedicine.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Publisher Correction: On the issue of transparency and reproducibility in nanomedicine.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Titania coating of mesoporous silica nanoparticles for improved biocompatibility and drug release within blood vessels.

Blood vessel disease is a major contributor to cardiovascular morbidity and mortality and is hallmarked by dysfunction of the lining endothelial cells (ECs). These cells play a significant role in vascular homeostasis, through the release of mediators to control vessel diameter, hence tissue perfusion. Mesoporous silica nanoparticles (MSNs) can be used as potential drug delivery platforms for vasodilator drugs. Here, using an ex vivo model of vascular function, we examine the use of titania coating for improved biocompatibility and release dynamics of MSN loaded sodium nitroprusside (SNP). MSNs (95 ±â€¯23 nm diameter; pore size 2.7 nm) were synthesised and fully characterised. They were loaded with SNP and coated with titania (TiO2), using the magnetron sputtering technique. Pre-constricted aortic vessels were exposed to drug loaded MSNs (at 1.96 × 1012 MSN mL-1) and the time course of vessel dilation observed, in real time. Exposure of viable vessels to MSNs lead to their internalization into the cytoplasm of ECs, while TiMSNs were also observed in the elastic lamina and smooth muscle cell layers. We demonstrate that titania coating of MSNs significantly improves their biocompatibility and alters the dynamics of drug release. A slow and more sustained relaxation was evident after uptake of TiMSN-SNP, in comparison to uncoated MSN-SNP (rate of dilation was 0.08% per min over a 2.5 h period). The use of titania coated MSNs for drug delivery to the vasculature may be an attractive strategy for therapeutic clinical intervention in cardiovascular disease. STATEMENT OF SIGNIFICANCE: Cardiovascular disease is a major cause of mortality and morbidity worldwide, with a total global cost of over $918 billion, by 2030. Mesoporous silica nanoparticles (MSNs) have great potential for the delivery of drugs that can treat vessel disease. This paper provides the first description for the use of titania coated MSNs with increased vascular penetration, for the delivery of vasodilator drugs, without compromising overall vessel function. We demonstrate that titania coating of MSNs significantly improves their biocompatibility and uptake within aortic blood vessels and furthermore, enables a slower and more sustained release of the vasodilator drug, sodium nitroprusside within the vessel, thus making them an attractive strategy for the treatment of vascular disease.

Polyvinylpyrrolidone-coated gold nanoparticles inhibit endothelial cell viability, proliferation, and ERK1/2 phosphorylation and reduce the magnitude of endothelial-independent dilator responses in isolated aortic vessels.

BACKGROUND: Gold nanoparticles (AuNPs) demonstrate clinical potential for drug delivery and imaging diagnostics. As AuNPs aggregate in physiological fluids, polymer-surface modifications are utilized to allow their stabilization and enhance their retention time in blood. However, the impact of AuNPs on blood vessel function remains poorly understood. In the present study, we investigated the effects of AuNPs and their stabilizers on endothelial cell (EC) and vasodilator function. MATERIALS AND METHODS: Citrate-stabilized AuNPs (12±3 nm) were synthesized and surface-modified using mercapto polyethylene glycol (mPEG) and polyvinylpyrrolidone (PVP) polymers. Their uptake by isolated ECs and whole vessels was visualized using transmission electron microscopy and quantified using inductively coupled plasma mass spectrometry. Their biological effects on EC proliferation, viability, apoptosis, and the ERK1/2-signaling pathway were determined using automated cell counting, flow cytometry, and Western blotting, respectively. Endothelial-dependent and independent vasodilator functions were assessed using isolated murine aortic vessel rings ex vivo. RESULTS: AuNPs were located in endothelial endosomes within 30 minutes' exposure, while their surface modification delayed this cellular uptake over time. After 24 hours' exposure, all AuNPs (including polymer-modified AuNPs) induced apoptosis and decreased cell viability/proliferation. These inhibitory effects were lost after 48 hours' exposure (except for the PVP-modified AuNPs). Furthermore, all AuNPs decreased acetylcholine (ACh)-induced phosphorylation of ERK1/2, a key signaling protein of cell function. mPEG-modified AuNPs had lower cytostatic effects than PVP-modified AuNPs. Citrate-stabilized AuNPs did not alter endothelial-dependent vasodilation induced by ACh, but attenuated endothelial-independent responses induced by sodium nitroprusside. PVP-modified AuNPs attenuated ACh-induced dilation, whereas mPEG-modified AuNPs did not, though this was dose-related. CONCLUSION: We demonstrated that mPEG-modified AuNPs at a therapeutic dosage showed lower cytostatic effects and were less detrimental to vasodilator function than PVP-modified AuNPs, indicating greater potential as agents for diagnostic imaging and therapy.

An arsenal of magnetic nanoparticles; perspectives in the treatment of cancer.

Nanomedicine is an emerging field, which constitutes a new direction in the treatment of cancer. Magnetic nanoparticles (MNPs) can circumvent vascular tissue to concentrate at the site of the tumor. Under the influence of an external, alternating magnetic field, MNPs generate high temperatures within the tumor and ablate malignant cells while inflicting minimal damage to healthy host tissue. Due to their theranostic properties, they constitute a promising candidate for the treatment of cancer. A critical review of the type, size and therapeutic effect of different MNPs is presented, following an appraisal of the literature in the last 5 years. This is a multibillion dollar industry, with a few studies moving to clinical trials within the next 5 years.

Real-time observation of aortic vessel dilation through delivery of sodium nitroprusside via slow release mesoporous nanoparticles.

Spherical mesoporous nanoparticles (MNPs) with a diameter of ∼100nm were synthesised via a sol-gel method in the presences of organic template (with and without fluorescein dye encapsulation). The template molecules were removed by acidic extraction to form a regular pore lattice structure. The nanoparticle size and morphology were analysed using transmission electron microscopy and dynamic light scattering analysis. The MNPs were further characterised by zeta potential, nitrogen adsorption measurements and infra-red spectroscopy. The interior pores had an average diameter of ∼3nm and were loaded with an endothelial-independent vasodilator, sodium nitroprusside (SNP). The optimal drug loading and drug release was determined in high potassium physiological salt solution using dialysis and atomic absorption spectroscopy. We demonstrate that the initial instantaneous release is due to the surface desorption of the drug followed by diffusion from the pores. Furthermore, these drug loaded MNPs (with and without fluorescein dye encapsulation) were added to viable aortic vessels and release in real-time was observed, ex vivo. MNPs and loaded with and without SNP were incubated with the vessel (at 1.96×10(12)NPmL(-1)) over a 3h time period. The real-time exposure to unloaded MNPs resulted in a small attenuation in constriction that occurred after approximately 1h. In contrast, MNPs loaded with SNP led to a rapid relaxation of aortic vessels that was sustained over the 3h period (p<0.001).

The influence of silica nanoparticles on small mesenteric arterial function.

AIM: To determine the influence of silica nanoparticles (SiNPs) on small arterial function; both ex vivo and in vivo. METHODS: Mono-dispersed dye-encapsulated SiNPs (97.85 ± 2.26 nm) were fabricated and vasoconstrictor and vasodilator responses of mesenteric arteries assessed. RESULTS: We show that while exposure to SiNPs under static conditions, attenuated endothelial dependent dilator responses ex vivo, attenuation was only evident at lower agonist concentrations, when exposed under flow conditions or after intravenous administration in vivo. Pharmacological inhibition studies suggest that SiNPs may interfere with the endothelial dependent hyperpolarizing factor vasodilator pathway. CONCLUSION: The dosage dependent influence of SiNPs on arterial function will help identify strategies for their safe clinical administration.

The effects of resveratrol on aging vessels.

Aging is a major risk factor for the development of cardiovascular disease. Despite a significant reduction in the mortality and morbidity rates over the last decade, the socio-economic burden of cardiovascular disease is still substantial. Consequently, there is a considerable need for alternative strategies, such as nutraceutical supplementation, that delay the functional vascular decline present in the elderly. Compromised autophagy and oxidative stress (OS) are considered major causes of the age-related endothelial dysfunction. OS reduces the bioavailability of nitric oxide (NO), which has been associated with hypertension, arteriosclerosis, and a reduced vasodilatory response. High levels of free radicals and the low bioavailability of NO lead to a positive feedback loop of further OS, organelle damage, poor repair, and endothelial dysfunction. Here we draw attention to the relationship between OS and autophagy in the aged vasculature. We have reviewed the published literature and provided arguments that support that treatment with resveratrol stimulates autophagy and thereby has the potential to restore oxidative balance in the endothelium, which indicates that treatment with resveratrol might have therapeutic potential to restore endothelial function in the elderly.

Attenuation of endothelial-dependent vasodilator responses, induced by dye-encapsulated silica nanoparticles, in aortic vessels.

AIM: To determine the influence of silica nanoparticle (SiNP) number, size and dye encapsulation on conduit arterial function, in vitro. MATERIALS & METHODS: Rhodamine B isothiocyanate (RBITC) dye molecules were encapsulated in a silica shell to produce nanoparticles (silica RBITC nanoparticles) smaller than 100 nm size. Their effects on endothelial-dependent (acetylcholine; 0.01-200 µM) and -independent (sodium nitroprusside; 0.001-10 µM) dilator responses were examined. RESULTS: When incubated with 1.96 × 10(12) nanoparticles/ml, both 30 and 70 nm SiNPs and silica RBITC nanoparticles significantly reduced endothelium-dependent, but not -independent, vasodilation. The degree of attenuation was related to nanoparticle surface area, rather than size, and influenced by dye encapsulation. Furthermore, attenuated dilation due to silica RBITC nanoparticles, but not SiNPs, could be partially restored using superoxide dismutase. CONCLUSION: Our results suggest that the mechanism of attenuated dilation is different for SiNPs and silica RBITC nanoparticles, which has implications for the future fabrication of biocompatible nanoparticles for imaging diagnostics.