Angiotensin converting enzyme inhibition lowers body weight and improves glucose tolerance in C57BL/6J mice maintained on a high fat diet

The renin–angiotensin system (RAS) is functional within adipose tissue and angiotensin II, the active component of RAS, has been implicated in adipose tissue hypertrophy and insulin resistance. In this study, captopril, an angiotensin converting enzyme (ACE) inhibitor that prevents angiotensin II formation, was used to study the development of diet-induced obesity and insulin resistance in obesity prone C57BL/6J mice. The mice were fed a high fat diet (w/w 21% fat) and allowed access to either water or water with captopril added (0.2 mg/ml). Body weight was recorded weekly and water and food intake daily. Glucose tolerance was determined after 11–12 weeks. On completion of the study (after 16 weeks of treatment), the mice were killed and kidney, liver, epididymal fat and extensor digitorum longus muscle (EDL) were weighed. Blood samples were collected and plasma analysed for metabolites and hormones. Captopril treatment decreased body weight in the first 2 weeks of treatment. Food intake of captopril-treated mice was similar to control mice prior to weight loss and was decreased after weight loss. Glucose tolerance was improved in captopril-treated mice. Captopril-treated mice had less epididymal fat than control mice. Relative to body weight, captopril-treated mice had increased EDL weight. Relative to control mice, mice administered captopril had a higher plasma concentration of adiponectin and lower concentrations of leptin and non-esterified fatty acids (NEFA). The results indicate that captopril both induced weight loss and improved insulin sensitivity. Thus, captopril may eventually be used for the treatment of obesity and Type 2 diabetes.

Effect of selenium-saturated bovine lactoferrin (Se-bLF) on antioxidant enzyme activities in human gut epithelial cells under oxidative stress

Cancer and many chronic inflammatory diseases are associated with increased amounts of reactive oxygen species (ROS). The potential cellular and tissue damage created by ROS has significant impact on many disease and cancer states and natural therapeutics are becoming essential in regulating altered redox states. We have shown recently that iron content is a critical determinant in the antitumour activity of bovine milk lactoferrin (bLF). We found that 100% iron-saturated bLF (Fe-bLF) acts as a potent natural adjuvant and fortifying agent for augmenting cancer chemotherapy and thus has a broad utility in the treatment of cancer. Furthermore, we also studied the effects of iron saturated bLF's ability as an antioxidant in the human epithelial colon cancer cell line HT29, giving insights into the potential of bLF in its different states. Thus, metal saturated bLF could be implemented as anti-cancer neutraceutical. In this regard, we have recently been able to prepare a selenium (Se) saturated form of bLF, being up to 98% saturated. Therefore, the objectives of this study were to determine how oxidative stress induced by hydrogen peroxide (H₂O₂) alters antioxidant enzyme activity within HT29 epithelial colon cancer cells, and observe changes in this activity by treatments with different antioxidants ascorbic acid (AA), Apo (iron free)-bLF and selenium (Se)-bLF. The states of all antioxidant enzymes (glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-s-transferase (GsT), catalase and superoxide dismutase (SOD)) demonstrated high levels within untreated HT29 cells compared to the majority of other treatments being used, even prior to H₂O₂ exposure. All enzymes showed significant alterations in activity when cells were treated with antioxidants AA, Apo-bLF or Se-bLF, with and/or without H₂O₂ exposure. Obvious indications that the Se content of the bLF potentially interacted with the glutathione (GSH)/GPx/GR/GsT associated redox system could be observed immediately, showing capability of Se-bLF being highly beneficial in helping to maintain a balance between the oxidant/antioxidant systems within cells and tissues, especially in selenium deficient systems. In conclusion, the antioxidative defence activity of Se-bLf, investigated in this study for the first time, shows dynamic adaptations that may allow for essential protection from the imbalanced oxidative conditions. Because of its lack of toxicity and the availability of both selenium and bLF in whole milk, Se-bLF offers a promise for a prospective natural dietary supplement, in addition to being an immune system enhancement, or a potential chemopreventive agent for cancers.

Enzyme-assisted extraction of bioactives from plants

Demand for new and novel natural compounds has intensified the development of plant-derived compounds known as bioactives that either promote health or are toxic when ingested. Enhanced release of these bioactives from plant cells by cell disruption and extraction through the cell wall can be optimized using enzyme preparations either alone or in mixtures. However, the biotechnological application of enzymes is not currently exploited to its maximum potential within the food industry. Here, we discuss the use of environmentally friendly enzyme-assisted extraction of bioactive compounds from plant sources, particularly for food and nutraceutical purposes. In particular, we discuss an enzyme-assisted extraction of stevioside from Stevia rebaudiana, as an example of a process of potential value to the food industry.

Enzyme-triggered self-assembly of peptide hydrogels via reversed hydrolysis

We demonstrate that proteases can be used to selectively trigger the self-assembly of peptide hydrogels via reversed hydrolysis.

Enzyme-assisted self-assembly under thermodynamic control

The production of functional molecular architectures through self-assembly is commonplace in biology, but despite advances^{1, 2, 3}, it is still a major challenge to achieve similar complexity in the laboratory. Self-assembled structures that are reproducible and virtually defect free are of interest for applications in three-dimensional cell culture^{4, 5}, templating⁶, biosensing⁷ and supramolecular electronics⁸. Here, we report the use of reversible enzyme-catalysed reactions to drive self-assembly. In this approach, the self-assembly of aromatic short peptide derivatives^{9, 10} provides a driving force that enables a protease enzyme to produce building blocks in a reversible and spatially confined manner. We demonstrate that this system combines three features: (i) self-correction—fully reversible self-assembly under thermodynamic control; (ii) component-selection—the ability to amplify the most stable molecular self-assembly structures in dynamic combinatorial libraries^{11, 12, 13}; and (iii) spatiotemporal confinement of nucleation and structure growth. Enzyme-assisted self-assembly therefore provides control in bottom-up fabrication of nanomaterials that could ultimately lead to functional nanostructures with enhanced complexities and fewer defects.

Myocardial ischemia-reperfusion injury, antioxidant enzyme systems, and selenium : A review

Coronary heart disease (CHD) remains the greatest killer in the Western world, and although the death rate from CHD has been falling, the current increased prevalence of major risk factors including obesity and diabetes, suggests it is likely that CHD incidence will increase over the next 20 years. In conjunction with preventive strategies, major advances in the treatment of acute coronary syndromes and myocardial infarction have occurred over the past 20 years. In particular the ability to rapidly restore blood flow to the myocardium during heart attack, using interventional cardiologic or thrombolytic approaches has been a major step forward. Nevertheless, while 'reperfusion' is a major therapeutic aim, the process of ischemia followed by reperfusion is often followed by the activation of an injurious cascade. While the pathogenesis of ischemia-reperfusion is not completely understood, there is considerable evidence implicating reactive oxygen species (ROS) as an initial cause of the injury.

ROS formed during oxidative stress can initiate lipid peroxidation, oxidize proteins to inactive states and cause DNA strand breaks, all potentially damaging to normal cellular function. ROS have been shown to be generated following routine clinical procedures such as coronary bypass surgery and thrombolysis, due to the unavoidable episode of ischemia-reperfusion. Furthermore, they have been associated with poor cardiac recovery post-ischemia, with recent studies supporting a role for them in infarction, necrosis, apoptosis, arrhythmogenesis and endothelial dysfunction following ischemia-reperfusion. In normal physiological condition, ROS production is usually homeostatically controlled by endogenous free radical scavengers such as superoxide dismutase, catalase, and the glutathione peroxidase and thioredoxin reductase systems. Accordingly, targeting the generation of ROS with various antioxidants has been shown to reduce injury following oxidative stress, and improve recovery from ischemia-reperfusion injury.

This review summarises the role of myocardial antioxidant enzymes in ischemia-reperfusion injury, particularly the glutathione peroxidase (GPX) and the thioredoxin reductase (TxnRed) systems. GPX and TxnRed are selenocysteine dependent enzymes, and their activity is known to be dependent upon an adequate supply of dietary selenium. Moreover, various studies suggest that the supply of selenium as a cofactor also regulates gene expression of these selenoproteins. As such, dietary selenium supplementation may provide a safe and convenient method for increasing antioxidant protection in aged individuals, particularly those at risk of ischemic heart disease, or in those undergoing clinical procedures involving transient periods of myocardial hypoxia.

Nanobiotechnology as a novel paradigm for enzyme immobilisation and stabilisation with potential applications in biodiesel production

Nanobiotechnology is emerging as a new frontier of biotechnology. The potential applications of nanobiotechnology in bioenergy and biosensors have encouraged researchers in recent years to investigate new novel nanoscaffolds to build robust nanobiocatalyt

Nurse-led titration of angiotensin converting enzyme inhibitors, beta-adrenergic blocking agents and angiotensin receptor blockers for patients with left ventricular systolic dysfunction

This is the protocol for a review and there is no abstract. The objectives are as follows:

To assess the effects of nurse-led titration of ACEIs, beta-adrenergic blocking agents and ARBs in patients with left ventricular systolic dysfunction in terms of safety and patient outcomes.