Effect of seaweed and cholesterol-enriched diets on postprandial lipoproteinaemia in rats.

High postprandial lipaemia increases cardiovascular risk. Algae consumption may affect postprandial lipoproteinaemia. The effects of dietary alga and cholesterol supplementation on postprandial lipaemia and lipoproteinaemia and arylesterase (AE) activity in growing male Wistar rats were tested in the present study. Six groups of ten rats were fed a casein-based diet for 3 weeks. Three of the diets contained 2.4 % cholesterol-raising agent (Chol), while the other three did not (NChol). Seven percentage of the control diets (NChol-C and Chol-C) consisted of a cellulose-wheat starch mix (35:65), while the Nori alga diets (NChol-N and Chol-N) and Konbu diets (NChol-K and Chol-K) contained 7 % of each respective freeze-dried alga. Postprandial plasma was obtained after a 3 h diet withdrawal. Supplementary cholesterol and alga type significantly affected (at least P < 0.05) the cholesterol, TAG, phospholipid and protein contents of the various lipoprotein fractions. AE enzyme activity increased (P < 0.05) in NChol rats given Nori and Konbu diets. NChol-K, but not NChol-N, rats displayed higher (P < 0.05) plasma cholesterol, TAG and phospholipid levels than NChol-C animals. NChol-K rats presented higher TAG, phospholipid, protein and lipoprotein mass values than their NChol-C counterparts. Inclusion of algae in Chol diets decreased (P < 0.001) the postprandial hypertriacylglycerolaemia. The Chol-N diet affected most lipoprotein fraction contents. Chol-N rats had lower postprandial cholesterolaemia and a better lipoprotein profile (fewer LDL and a tendency toward more HDL and fewer cholesterol-enriched VLDL) than Chol-K rats, suggesting that Nori is the alga of choice in dietary treatment of hypercholesterolaemia.

Growth hormone improves lipoprotein concentration and arylesterase activity in mice with an atherogenic lipid profile induced by lactalbumin.

The effect of growth hormone (GH) on arylesterase (AE), one of the activities of paraoxonase, has never been studied. The aims of the present study in mice were: (a) to compare the effect of age and sex on serum lipid and lipoprotein levels after consumption of lactalbumin- v. chow-based diets and (b) to study the effect of GH administration, age and sex on serum AE activity, lipid and lipoprotein and body fat levels in mice fed a lactalbumin diet. Seventy-two mice were divided into three age- and sex-matched experimental groups: (1) control chow (CC), (2) non-GH lactalbumin (NGL) and (3) GH-treated lactalbumin (GL) mice. Lactalbumin increased total cholesterol, (LDL+VLDL)-cholesterol and TAG and diminished HDL-cholesterol in all animals (P<0.05). In comparison with their NGL counterparts, old GL males presented lower total cholesterol (15%) and (LDL+VLDL)-cholesterol (17%) levels (P<0.05), whereas values of the same parameters were higher in adult GL males (P<0.05) (22 and 23%, respectively). Adult GL females displayed higher serum HDL-cholesterol concentrations (26%) (P<0.05) than adult NGL females. AE activity was lower in old GL females (78%) and old GL males (20%) (P<0.05), but higher in adult GL males (100%) (P<0.01). GH, that was inversely related to food intake, decreased abdominal and gonadal fat in all mice (P<0.05). To conclude, lactalbumin induced an atherogenic lipoprotein profile in NGL mice that was reverted by GH, preferentially in old males, suggesting that GH therapy will be more effective in aged men. The present results suggest that AE activity was age-, sex- and body fat level-dependent and that it diminished as a consequence of improved antioxidant status.

Mesoporous silica nanoparticles as a new carrier methodology in the controlled release of the active components in a polypill.

Polypill is a medication designed for preventing heart attacks through a combination of drugs. Current formulations contain blood pressure-lowering drugs and others, such statins or acetylsalicylic acid. These drugs exhibit different physical chemical features, and consequently different release kinetics. Therefore, the concentration in plasma of some of them after the release process can be out of the therapeutic range. This paper investigates a new methodology for the control dosage of a polypill recently reported containing hydrochlorothiazide, amlodipine, losartan and simvastatin in a 12.5/2.5/25/40 weight ratio. The procedure is based on mesoporous silica nanoparticles (MSN) with MCM-41 structure (MSN-41) used as carrier, aimed to control release of the four drugs included in the polypill. In vitro release data were obtained by HPLC and the curves adjusted with a kinetic model. To explain the release results, a molecular model was built to determine the drug-matrix interactions, and quantum mechanical calculations were performed to obtain the electrostatic properties of each drug. Amlodipine, losartan and simvastatin were released from the polypill-MSN-41 system in a controlled way. This would be a favourable behavior when used clinically because avoid too quick pressure decrease. However, the diuretic hydrochlorothiazide was quickly released from our system in the first minutes, as is needed in hypertensive urgencies. In addition, an increase in the stability of amlodipine and hydrochlorothiazide occurred in the polypill-MSN-41 system. Therefore, the new way of polypill dosage proposed can result in a safer and effective treatment.

A new method for the determination of arylesterase activity in human serum using simulated body fluid.

Arylesterase activity (EC 3.1.1.2), one of the three functions of the paraoxonase enzyme (PON1), is thought to protect low-density lipoproteins (LDL) and high-density lipoprotein (HDL) from oxidation and to facilitate reverse cholesterol transport. The Eckerson et al. method, which employs Tris/HCl buffer, has been extensively used and could be considered as the reference method, although it shows relatively low precision and reproducibility. Using simulated body fluid (SBF), which simulates blood electrolyte composition, a significant improvement in arylesterase activity determination was achieved. Modifications of SBF bicarbonate and chloride concentrations did not result in further improvements. To validate this method arylesterase activity was measured using SBF and Tris/HCl in 23 subjects with increased cardiovascular disease risk. Precision was significantly higher using SBF than with Tris/HCl. Data from both methods do not significantly differ in samples with arylesterase activity > or = 30.6 U/L using SBF, but do differ significantly when very low activity samples (< 30.6 U/L) were included. Differences suggest that the Tris/HCl buffer gives misleading activity results, especially in very low activity samples. For the first time, results suggest that SBF can successfully be used instead of Tris/HCl in arylesterase activity determination.

Understanding Candida rugosa lipases: an overview.

Candida rugosa lipase (CRL) is one of the enzymes most frequently used in biotransformations. However, there are some irreproducibility problems inherent to this biocatalyst, attributed either to differences in lipase loading and isoenzymatic profile or to other medium-engineering effects (temperature, a(w), choice of solvent, etc.). In addition, some other properties (influence of substrate and reaction conditions on the lid movement, differences in the glycosylation degree, post-translational modifications) should not be ruled out. In the present paper the recent developments published in the CRL field are overviewed, focusing on: (a) comparison of structural and biochemical data among isoenzymes (Lip1-Lip5), and their influence in the biocatalytical performance; (b) developments in fermentation technology to achieve new crude C. rugosa lipases; (c) biocatalytical reactivity of each isoenzyme, and methods for characterising them in crude CRL; (d) state-of-the-art of new applications performed with recombinant CRLs, both in CRL-second generation (wild-type recombinant enzymes), as well as in CRL-third generation, (mutants of the wt-CRL).

Nanonets Derived from Turnip Mosaic Virus as Scaffolds for Increased Enzymatic Activity of Immobilized Candida antarctica Lipase B.

Elongated flexuous plant viral nanoparticles (VNPs) represent an interesting platform for developing different applications in nanobiotechnology. In the case of potyviruses, the virion external surface is made up of helically arrayed domains of the viral structural coat protein (CP), repeated over 2000 times, in which the N- and C-terminal domains of each CP are projected toward the exterior of the external virion surface. These characteristics provide a chemical environment rich in functional groups susceptible to chemical conjugations. We have conjugated Candida antarctica lipase B (CALB) onto amino groups of the external surface of the potyvirus turnip mosaic virus (TuMV) using glutaraldehyde as a conjugating agent. Using this approach, TuMV virions were transformed into scaffolds for CALB nanoimmobilization. Analysis of the resulting structures revealed the formation of TuMV nanonets onto which large CALB aggregates were deposited. The functional enzymatic characterization of the CALB-bearing TuMV nanonets showed that CALB continued to be active in the nanoimmobilized form, even gaining an increased relative specific activity, as compared to the non-immobilized form. These novel virus-based nanostructures may provide a useful new approach to enzyme nanoimmobilization susceptible to be industrially exploited.

Drug release from ordered mesoporous silicas.

The state-of-the-art in the investigation of drugs release from Silica-based ordered Mesoporous Materials (SMMs) is reviewed. First, the SMM systems used like host matrixes are described. Then, the model drugs studied until now, including their pharmacological action, structure and the mesoporous matrix employed for each drug, are comprehensively listed. Next, the factors influencing the release of drugs from SMMs and the strategies used to control the drug delivery, specially the chemical functionalization of the silica surface, are discussed. In addition, how all these factors were gathered in a kinetic equation that describes the drug release from the mesoporous matrixes is explained. The new application of molecular modeling and docking in the investigation of the drug delivery mechanisms from SMMs is also presented. Finally, the new approaches under investigation in this field are mentioned including the design of smart stimuli-responsive materials and other recent proposals for a future investigation.

Effect of walnut-enriched restructured meat in the antioxidant status of overweight/obese senior subjects with at least one extra CHD-risk factor.

BACKGROUND: A number of recent studies indicate that antioxidants reduce the oxidative stress associated with the development of coronary heart diseases (CHD). OBJECTIVE: (i) To investigate whether the erythrocyte catalase (CAT), superoxide dismutase (SOD), total glutathione, reduced glutathione (GSH), oxidized glutathione (GSSG), and lipid peroxidation (LPO), and serum uric acid and paraoxonase-1 (PON1) are modified at increased CHD-risk individuals consuming walnut-enriched meat (WM), (ii) to evaluate whether these changes were influenced by basal serum cholesterol, body mass index or smoking habit. DESIGN: The study was a non blinded, cross-over, placebo-controlled trial in which 22 volunteers (60% overweight and 40% obese) with increased CHD-risk were randomly assigned to receive WM or control meat (CM) during two different periods of 5 weeks. RESULTS: A significant interaction time*treatment (p < 0.05) was observed in all enzymes and substrates tested except HDL-C, uric acid and LPO. The treatment significantly increased CAT activity, total glutathione and GSSG (p < 0.05). Significant gender*time*treatment interaction (p = 0.043) for total glutathione was found increasing at the end of the WM period in male but not changing in female. Total glutathione and GSH/GSSG ratio (p < 0.05) were lower in smokers. Hypercholesterolemics presented higher uric acid (p < 0.05) but no enzyme activities or substrate concentrations were different from those of normocholesterolemics. CONCLUSIONS: The WM tested appears to be a functional food as it improved the antioxidant status of increased CHD-risk volunteers. Despite its high energy content, it also appears adequate for overweight and obese people because did not exert negative effect upon body weight.

Arylesterase activity and antioxidant status depend on PON1-Q192R and PON1-L55M polymorphisms in subjects with increased risk of cardiovascular disease consuming walnut-enriched meat.

Human paraoxonase (PON1) exists in 2 major polymorphic forms and has been shown to protect LDL and HDL against oxidation. The aim of this study was to assess the differences between subjects at increased risk of cardiovascular disease (CVD), taking into account the effects of PON1-Q192R and PON1-L55M polymorphisms on 1) basal serum arylesterase activity, lipid peroxidation (LPO), and LDL-cholesterol (LDL-C), HDL-C, total cholesterol (TC), and oxidized-LDL (ox-LDL) concentrations; 2) the relations between arylesterase activity and lipid variables; and 3) the effect of walnut-enriched meat (WM) consumption on arylesterase activity and lipid variables. Twenty-three Caucasians at increased risk of CVD were randomly assigned to diet order groups in a crossover, nonblinded, placebo-controlled trial, consisting of two 5-wk experimental periods [WM and control meat (CM)]. Significant PON1-L55M x PON1-Q192R interactions affected basal serum HDL-C (P = 0.019), LDL-C (P = 0.028) and TC (P = 0.022) and tended to affect arylesterase activity (P = 0.083). Basal arylesterase activity was positively correlated with basal HDL-C (r = 0.53; P < 0.05) and TC (r = 0.43; P < 0.05) and negatively correlated with LPO (r = -0.70; P < 0.01) and the ox-LDL:LDL ratio (r = -0.63; P < 0.01). WM decreased arylesterase activity in PON1-55M carriers (P = 0.012) but not in PON1-L55 individuals, and decreased LPO concentrations in PON1-192R carriers (P = 0.031) but not in PON1-Q192 subjects. To conclude, serum TC, HDL-C, and LDL-C concentrations and arylesterase activity depend on the interaction of PON1-L55M and PON1-Q192R polymorphisms. However, the PON1-Q192R polymorphism is more closely related to antioxidant status. Both polymorphisms modulate the effect of WM consumption on CVD biomarkers.

Rational strategy for the production of new crude lipases from Candida rugosa.

Candida rugosa was cultured using different inducers (oleic acid, olive oil, sunflower oil, n-dodecanol and glycerol) as the only carbon source in batch conditions, as well as in several fed-batch fermentations (oleic acid as inducer) at variable feed rate conditions. The N-terminal analysis of each crude lipase revealed that, while the isoenzymes Lip2 and Lip3 are always secreted (at different proportions depending on the inducer), Lip1 was produced only using n-dodecanol (batch conditions) or oleic acid (fed-batch at high feed rate). The nature of the inducer controls the isoenzyme percentage; when this is fixed, as well as the feed rate in fed-batch fermentation, the isoenzymatic profile remained unaltered and the samples differed only in the activity of the lipases, as determined by heptyl oleate synthesis.