Antioxidant activity of hydroxytyrosol in frankfurters enriched with n-3 polyunsaturated fatty acids

8 páginas,6 tablas.The capacity of hydroxytyrosol (HXT) to inhibit lipid oxidation in cooked pork meat batter, oil-in-water emulsions and potential functional frankfurters formulated with a healthier oil combination (as animal fat replacer) was studied during chilling storage, and its effect compared with those produced by synthetic antioxidants (BHA/BHT). Although efficiency varied, HXT was an effective antioxidant during chilling storage in the three food matrices studied. In general the order of inhibition capacity of HXT against lipid oxidation (thiobarbituric acid-reactive substances-TBARS) was cooked meat batter > oil-in-water emulsion > frankfurters, whereas in the case of BHA/BHT (with lower inhibitory activity than HXT) it was cooked meat batter > oil-in-water emulsion, and there was no antioxidative effect in frankfurters. Whereas significant correlations were established between lipid oxidation (TBARS) and antioxidative capacity measured by photochemiluminescence (PCL) in frankfurters supplemented with HXT and BHA/BHT, no significant correlations were found between ferric reducing/antioxidant power assay (FRAP) and TBARS and PCL.This research was supported by the projects AGL2008-04892- CO3-01 and Consolider Ingenio 2010: CARNISENUSA (CSD2007- 00016).Peer reviewe

Intravascular photoacoustics as a theranostic platform for atherosclerosis

textThe persistence of high global mortality rates directly attributable to cardiovascular disease drives ongoing research into novel approaches for improved diagnosis and treatment of its primary underlying cause, atherosclerosis. Combined intravascular ultrasound and photoacoustic (IVUS/IVPA) imaging is one such modality, actively being developed as a tool for improved characterization of high-risk atherosclerotic plaques. The pathophysiology associated with progression and destabilization of atherosclerotic plaques leads to characteristic changes in arterial morphology and composition. IVUS/IVPA imaging seeks to expand upon the ability of clinically utilized intravascular ultrasound (IVUS) imaging to assess vessel anatomy by adding improved sensitivity to image the underlying cellular and molecular composition through intravascular photoacoustic (IVPA) imaging of either endogenous chromophores (e.g. lipid) or exogenously delivered contrast agents. This dissertation focuses on the expansion of IVUS/IVPA imaging using exogenous contrast agents to enable the detection and subsequent optically-triggered therapy of atherosclerotic plaques. The passive extravasation and aggregation of systemically injected plasmonic gold nanorods absorbing within the near infrared tissue optical window within plaques of atherosclerotic rabbit models is first demonstrated, along with the ability to localize the contrast agents using ex vivo IVUS/IVPA imaging. The motivation for nanoparticle labeling of atherosclerosis is then expanded from that of purely image contrast agents to vehicles for image-guided, dual-modality phototherapy. The integrated IVUS/IVPA imaging catheter is utilized for photothermal delivery with simultaneous IVPA temperature monitoring using the high optical absorption of gold nanorod contrast agents to enable localized heating. Subsequently, the potential role for IVUS/IVPA-guided phototherapy is further expanded through the characterization and in vitro assessment of novel multifunctional theranostic nanoparticles comprised of a gold nanorod core with a degradable, photosensitizer-doped silica shell. Together, the results presented within this dissertation provide a framework for ongoing research into the expansion of IVUS/IVPA imaging as a platform for complimentary diagnosis and local treatment of atherosclerotic plaques using multifunctional theranostic nanoparticle contrast agents.Biomedical Engineerin

Study of derivatives for diagnostic imaging of early atheromatous lesions

Studio di derivati per l'imaging diagnostico precoce delle lesioni ateromasich

ACRYLAMIDE: A POSSIBLE RISK FACTOR FOR CARDIAC HEALTH

Acrylamide (ACR) is an important industrial chemical agent also a food contaminant formed when food rich in carbohydrates is processed at high temperatures (120°C) such as cooking, frying, roasting, toasting, and baking. It happens when amino acid asparagine reacts with sugars, especially glucose and fructose as a result of the Maillard reaction. Its potential to cause damage to humans and animals makes it a cause for concern. After its outbreak in 2002, extensive study has been going on to prevent its formation in food. Neurological effects are by far well established for ACR along with systemic toxic effects. Diet contributes to the high proportion of ACR intake on daily basis; other exposure media are occupational, environmental, and smoking. A number of studies justifying ACR cardiotoxicity, its clear mechanism and its relevance to humans are less, but some research papers suggest the possibility of cardiotoxicity or developmental cardiotoxicity. In this review, ACR cardiac toxic effects and mechanism pathway have been discussed along with mitigation strategies

The Effect of Repeated Electromagnetic Fields Stimulation in Biological Systems

The effects of electromagnetic fields on living organs have been explored with the use of both biological experimentation and computer simulations. In this paper we will examine the effects of the repeated electromagnetic field stimulation (REMFS) on cell cultures, mouse models, and computer simulations for diagnostic purposes. In our biological experiments we used 50 MHz and 64 MHz since this is approved in MRI systems. REMFS upregulated pathways that control the aging process such as proteostasis. REMFS delayed and reversed cellular senescence in mouse and human cell cultures. More recently we determined that REMFS decreases toxic protein beta amyloid levels, which is the cause of Alzheimer’s disease (AD), in human neuronal cultures. The mechanism of these effects is the reactivation of the heat shock factor 1 (HSF1). HSF1 activation is a quantum effect of the EMF-oscillations on the water that surrounds a long non-coding RNA, allowing it to then bind and activate the HSF1. We also performed electromagnetic (EM) computer simulations of virtual prototypes of bone cancer, femur fracture, and diabetic foot ulcers utilizing different frequencies and power applications to build an accurate differential diagnosis. These applications indicate the feasibility of subsequent practical models for diagnosing and treating human diseases

Block Copolymer Based Magnetic Nanoclusters for Cancer-Theranostics: Synthesis, Characterization and In Vitro Evaluation

“There is plenty of room at the bottom”. In this visionary lecture in 1959 Prof. Richard Feynman spoke of the interesting ramifications of working with matter at the atomic scale. Since then, scientists have worked relentlessly towards realizing his vision. The influence of nanobiotechnology on material science and polymer chemistry has given rise to a new field called ‘theranostics’, combining drug delivery and diagnostics within the same nanostructures, thereby enabling simultaneous diagnosis, targeted drug delivery and continued therapy monitoring. Iron oxide nanoparticles (MNPs) are one such class of MRI contrast agents that can be converted into theranostic nanomedicines for cancer therapy. However, development of a stable theranostic contrast system comprising of MNPs is complex and requires a careful balance between the therapeutic diagnostic components. We explored the potential of biodegradable hydrophilic block ionomers such as anionic poly (glutamic acid-b-ethylene glycol) and cationic poly (l-lysine-b-ethylene glycol) in formulating stable magnetic nanoclusters (MNCs). These MNCs were extensively characterized for their composition, colloidal stability and factors influencing their MRI capability. Extensive in vitro studies revealed that the anionic cisplatin-loaded MNCs showed minimal non-specific uptake, a highly preferred feature for targeted cancer therapy. Luteinizing hormone releasing hormone receptor (LHRHr) targeting significantly enhanced the uptake of these formulations in LHRHr-positive ovarian cancer cells. LHRHr targeting also helped improve the theranostic efficacy in cisplatin resistant ovarian cancer cells. One the other hand, cationic MNCs were used to demonstrate the potential of MNCs to function as stimuli-responsive theranostic systems capable of releasing the payload in the acidic milieu breast and ovarian cancer cells. These cationic MNCs also exhibited significantly enhanced T2-weighted MRI contrasts at much lower concentrations than the anionic counterparts. Finally, we successfully evaluated the feasibility of kinetically controlled flash nanoprecipitation technique using multi-inlet vortex mixer (MIVM) to formulate well-defined MNCs from non-ionic amphiphilic Pluronic tri-block copolymers. In comparison to self-assembly techniques, flash nanoprecipitation resulted in significant reduction in polydispersity. It was observed that the hydrophobic block-length of the copolymer dictates the extent of encapsulation hydrophobic therapeutic agents along with the MNPs. exhibited the potential to function as both T1 and T2 contrast agents. In summary, looking at the bigger picture, the work presented here emphasizes on the importance of product development in establishing a critical balance between the therapeutic and imaging functionalities when designing an efficient targeted theranostic nanosystems

Rapamycin-loaded polymeric nanoparticles as an advanced formulation for macrophage targeting in atherosclerosis

Recently, rapamycin (Rapa) represents a potential drug treatment to induce regression of atherosclerotic plaques; however, its use requires site-specific accumulation in the vessels involved in the formation of the plaques to avoid the systemic effects resulting from its indiscriminate biodistribution. In this work, a stable pharmaceutical formulation for Rapa was realized as a dried powder to be dispersed extemporaneously before administration. The latter was constituted by man-nitol (Man) as an excipient and a Rapa-loaded polymeric nanoparticle carrier. These nanoparticles were obtained by nanoprecipitation and using as a starting polymeric material a polycaprolactone (PCL)/α,β-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) graft copolymer. To obtain nanoparti-cles targeted to macrophages, an oxidized phospholipid with a high affinity for the CD36 receptor of macrophages, the 1-(palmitoyl)-2-(5-keto-6-octene-dioyl) phosphatidylcholine (KOdia-PC), was added to the starting organic phase. The chemical–physical and technological characterization of the obtained nanoparticles demonstrated that: both the drug loading (DL%) and the entrapment efficiency (EE%) entrapped drug are high; the entrapped drug is in the amorphous state, protected from degradation and slowly released from the polymeric matrix; and the KOdia-PC is on the nanoparticle surface (KP-Nano). The biological characterization demonstrated that both systems are quickly internalized by macrophages while maintaining the activity of the drug. In vitro studies demonstrated that the effect of KP-Nano Rapa-loaded, in reducing the amount of the Phospo-Ser757-ULK1 protein through the inhibition of the mammalian target of rapamycin (mTOR), is comparable to that of the free drug

VASCULAR AND METABOLIC ADAPTATIONS TO EXERCISE IN NON-ALCOHOLIC FATTY LIVER DISEASE

Non-alcoholic fatty liver disease (NAFLD) is characterised by the accumulation of fat in the liver and is associated with liver-related morbidity and mortality. Nevertheless, the leading cause of death in these patients is cardiovascular disease (CVD). Excess abdominal visceral adipose tissue (VAT) is frequently expressed in NAFLD and is considered a pivotal feature in the pathogenesis of NAFLD which is predictive of CVD. Endothelial dysfunction is an early manifestation in the development of atherosclerosis and is characterised by a diminished bioavailabilty of the anti-atherogenic molecule NO, which is secreted by the endothelium of all blood vessels throughout the vascular tree. Limited pharmacological treatment is available to reduce hepatic fat, therefore, lifestyle modification interventions comprised of structured exercise and diet are recommended as a non-pharmacological management strategy to reduce hepatic fat in NAFLD. The primary aim of this thesis was to explore nitric oxide (NO)-mediated endothelial function at different levels of the vascular tree in NAFLD patients and to establish whether supervised exercise training has a sustained therapeutic impact on endothelial function. Thirty-two NAFLD patients (21 males, 11 females, 48±2yrs, BMI 31±1kg/m2) and eighteen matched controls (8 males, 10 females, 48±2yrs, BMI 30±1kg/m2) underwent magnetic resonance imaging (MRI) to quantify abdominal VAT and proton magnetic resonance spectroscopy (1H-MRS) to determine intrahepatocellular triglyceride content (IHTC). Brachial artery flow mediated dilatation (FMD) (as an index of endothelial NO function) was also assessed. IHTC (27.2±3.0 vs. 2.9±0.4%) and abdominal VAT (5.4±0.3vs. 3.4±0.2 l) were elevated in NAFLD patients when compared with controls (P0.05). Impairment in FMD remained in NAFLD patients following independent covariate adjustment for abdominal VAT (5.0±0.5 vs. 7.3±0.7%, P=0.01). These findings indicate that excess IHTC and abdominal VAT do not explain endothelial dysfunction in NAFLD. Twenty NAFLD patients were randomly assigned to either 16-weeks of supervised moderate intensity (30-60% HRR, 30-45 min, 3-5 times per week) exercise training (n=13, 50±3yrs, BMI 30±1kg/m2) or to 16-weeks of conventional care lifestyle advice (n=7, 47±6yrs, BMI 31±2kg/m2). Supervised exercise training induced a greater improvement in FMD when compared with conventional care (3.6±0.6 vs. 0.3±0.8%, P=0.004). There was no significant difference between the effect of exercise and conventional care on IHTC or abdominal VAT (P>0.05). These data suggest that supervised exercise training is an effective management strategy in NAFLD capable of improving conduit artery endothelial function independent of IHTC and abdominal VAT. In order to explore the longevity of the exercise-induced improvements in conduit artery endothelial function, a 12-month follow up assessment was performed in 9 of the NAFLD patients (5 males, 4 females, 50±5yrs, BMI 30±1kg/m2) who completed the 16-week supervised exercise training intervention. The exercise-induced improvement in FMD (5.1±0.8 vs. 7.9±0.8%; P=0.004) was abolished 12 months following the cessation of supervised exercise training (7.9±0.8 vs.5.0±0.5%; P=0.02), returning to a similar level observed at baseline (5.1±0.8 vs. 5.0±0.5%; P=0.95).These findings indicate that in order to chronically sustain exercise-induced improvements in endothelial function in NAFLD patients, long-term exercise supervision and guidance is required. Cutaneous NO-mediated microvessel function reflects generalised microvascular function and provides a translational model to investigate pre-clinical disease, but has not been previously investigated in NAFLD. NO-mediated vasodilatation in the cutaneous microvessels was examined in 13 NAFLD patients (7 males, 6 females, 50±3yrs, BMI 31±1kg/m2) and 7 matched controls (3 males, 4 females, 48±4yrs, BMI 30±2 kg/m2). Microdialysis fibres were embedded into the skin of the forearm and laser Doppler probes placed over these sites. Both sites were then heated to 42°C, with saline solution infused in one probe and L-NG-monomethyl arginine (L-NMMA) through the second. Following baseline assessment, 11 NAFLD patients were randomly assigned to 16-weeks of supervised moderate intensity exercise training (n=6, 45±5yrs, BMI 31±1kg/m2) or to 16-weeks of conventional care (n=5, 51±3yrs, BMI 30±21kg/m2). The NO contribution to skin blood flow in response to incremental heating was not different between NAFLD patients and controls (P=0.47) at baseline. However, significant differences were evident in NO contribution between the exercise training and conventional care group (P=0.01), suggesting that supervised exercise training improves cutaneous NO-mediated microvascular endothelial function in NAFLD patients. This thesis suggests that supervised exercise training has a direct therapeutic impact on endothelial function in NAFLD which may decrease the risk of future heart disease and stroke. As a cardioprotective management strategy in NAFLD, exercise training is superior to that of current conventional care pathways, however, in order to chronically sustain the exercise-induced improvements in endothelial function, long term exercise supervision and guidance is required

Addressing Public Health Risks of Persistent Pollutants Through Nutritional Modulation and Biomimetic Nanocomposite Remediation Platforms

Due to their relative chemical stability and ubiquity in the environment, chlorinated organic contaminants such as polychlorinated biphenyls (PCBs) pose significant health risks and enduring remediation challenges. Engineered nanoparticles (NPs) provide a novel platform for sensing/remediation of these toxicants, in addition to the growing use of NPs in many industrial and biomedical applications, but there remains concern for their potential long-term health effects. Research highlighted herein also represents a transdisciplinary approach to address human health challenges associated with exposure to PCBs and NPs. The objectives of this dissertation research are two-fold, 1) to develop effective methods for capture/sensing and remediation of environmental toxicants, and 2) to better understand associated risks and to elucidate relevant protective mechanisms, such as lifestyle-related modulators of environmental disease. Prevalent engineered nanoparticles, including aluminum oxide and titanium dioxide, have been studied to better understand effective nanoparticle dispersion methods for in vitro nanotoxicology studies. This work has served both to effectively stabilize these nanoparticles under physiological conditions and to better understand the associated mechanisms of toxicity, which links these metal nanoparticles to endothelial oxidative stress and inflammation through phosphorylation of key cellular signaling molecules and increased DNA binding of pro-inflammatory NFκB. Surface functionalization, though, is being found to limit potential toxicity and has been utilized in subsequent research. A novel polyphenol-functionalized, NP-based system has been developed which combines the biomimetic binding capabilities of nutrient polyphenols with the separation and heating capabilities of superparamagnetic iron oxide NPs for the capture/sensing of organic contaminants in polluted water sources. Magnetic nanocomposite microparticles (MNMs) incorporating the fluorescent polyphenols quercetin and curcumin exhibit high affinity for model organic pollutants followed by rapid magnetic separation, addressing the need for sustainable pollutant remediation. Further work has been performed to both better understand health concerns associated with environmental toxicants such as PCBs and to determine effective methods for modulating their toxicity. This research has shown that PCB remediation through dechlorination is a viable technique for decreasing endothelial inflammation, although complete dechlorination to biphenyl is necessary to effectively eliminate superoxide production, NFκB activation, and induction of inflammatory markers. Additionally, the nutrient polyphenol EGCG, found in green tea, has been shown to serve as a biomedical modulator of in vivo PCB toxicity by up-regulating a battery of antioxidant enzymes transcriptionally controlled by AhR and Nrf2 proteins

Developing novel molecular contrast agents for imaging vulnerable plaques

This thesis describes the design, synthesis, and testing of novel MRI contrast agents based on iron oxide nanoparticles for the specific detection and identification of vulnerable plaque. Cardiovascular disease remains the leading cause of death worldwide, primarily due to heart attacks and strokes resulting from vulnerable plaque rupture. Vulnerable plaque occurs in atherosclerosis, when plaque is deposited in the walls of blood vessels and can take on vulnerable or stable phenotypes. There is an urgent need for an imaging biomarker to enable the specific detection of vulnerable plaque to facilitate treatment and prevent future heart attacks and strokes. MRI is a non-ionising, non-invasive imaging modality with the potential for highly customisable contrast agents. Chapter 2 discusses the design and synthesis of a library of superparamagnetic iron oxide nanoparticle-based contrast agents through thermal decomposition and coating with different surface ligands, including poly (maleic anhydride-alt-1-octadecene), alendronate, and poly (ethyleneimine). The agents were characterised through transmission electron microscopy, dynamic light scattering, zeta potential and relaxivity measurements. Chapter 3 presents the results of biological tests performed using the lead candidate from the synthesis carried out in chapter 2, including the coupling of a targeting antibody to the contrast agent, in vitro testing, and MR imaging in a preclinical model with histological verification of the results. Chapter 4 builds on the initial design and synthetic work of Chapter 2 with the introduction of a gold shell, moving towards multi-modality imaging. Several synthetic routes for the introduction of the gold shell and a selection of surface ligands including poly (maleic anhydride-alt-1-octadecene), homocysteine, and citrate were studied, and characterised through transmission electron microscopy, dynamic light scattering, and zeta potential measurements. Chapter 5 summarises the conclusions of the project, presents potential areas for future work and concludes the thesis. Open Acces