Antonio Cilla

Oxysterol Mixture in Hypercholesterolemia-Relevant Proportion Causes Oxidative Stress-Dependent Eryptosis

Background/Aims: Oxysterol activity on the erythrocyte (RBC) programmed cell death (eryptosis) had not been studied yet. Effects of an oxysterol mixture in hyper-cholesterolemic-relevant proportion, and of individual compounds, were investigated on RBCs from healthy humans. Methods: Membrane phosphatidylserine (PS) externalization, calcium entry, ROS production, amino-phospholipid translocase (APLT) activity were evaluated by cytofluorimetric assays, cell volume from forward scatter. Prostaglandin PGE2 was measured by ELISA; GSH-adducts and lipoperoxides by spectrophotometry. Involvement of protein kinase C and caspase was investigated by inhibitors staurosporin, calphostin C, and Z-DEVD-FMK, respectively. Results: Oxysterols caused PS externalization and cell shrinkage, associated with PGE2release, opening of PGE2-dependent calcium channels, ROS production, GSH depletion, membrane lipid oxidation. Addition of antioxidants prevented Ca2+ influx and eryptosis. Calcium removal prevented cell shrinkage, with small effect (-20%) on the PS exposure, whereas ROS generation was unaltered. Either in the presence or absence of calcium i) oxysterols inhibited APLT, ii) staurosporin, calphostin C, Z-DEVD-FMK blunted and iii) antioxidants fully prevented the oxysterol-induced PS externalization. Only 7-ketocholesterol and cholestan-3β,5α,6β-triol were individually active. Eryptosis was observed in RBCs isolated after ex vivo spiking of human whole blood with the oxysterol mixture. Conclusions: Oxysterols induce an oxidative stress-dependent eryptosis, involving calcium-independent mechanisms. Eryptotic activity of oxysterols may be relevant in vivo.

Mind the gap—deficits in our knowledge of aspects impacting the bioavailability of phytochemicals and their metabolites—a position paper focusing on carotenoids and polyphenols

Various secondary plant metabolites or phytochemicals, including polyphenols and carotenoids, have been associated with a variety of health benefits, such as reduced incidence of type 2 diabetes, cardiovascular diseases, and several types of cancer, most likely due to their involvement in ameliorating inflammation and oxidative stress. However, discrepancies exist between their putative effects when comparing observational and intervention studies, especially when using pure compounds. These discrepancies may in part be explained by differences in intake levels and their bioavailability. Prior to exerting their bioactivity, these compounds must be made bioavailable, and considerable differences may arise due to their matrix release, changes during digestion, uptake, metabolism, and biodistribution, even before considering dose‐ and host‐related factors. Though many insights have been gained on factors affecting secondary plant metabolite bioavailability, many gaps still exist in our knowledge. In this position paper, we highlight several major gaps in our understanding of phytochemical bioavailability, including effects of food processing, changes during digestion, involvement of cellular transporters in influx/efflux through the gastrointestinal epithelium, changes during colonic fermentation, and their phase I and phase II metabolism following absorption.

Bioaccessibility of tocopherols, carotenoids, and ascorbic acid from milk- and soy-based fruit beverages: influence of food matrix and processing.

A study was made of the effect of high-pressure processing (HPP) and thermal treatment (TT) on plant bioactive compounds (tocopherols, carotenoids, and ascorbic acid) in 12 fruit juice-milk beverages and of how the food matrix [whole milk (JW), skimmed milk (JS), and soy milk (JSy)] modulates their bioaccessibility (%). HPP (400 MPa/40 °C/5 min) produced a significant decrease in carotenoid and ascorbic acid bioaccessibility in all three beverages and maintained the bioaccessibility of tocopherols in JW and JS while decreasing it in JSy. TT (90 °C/30 s) produced a significant decrease in tocopherol and carotenoid bioaccessibility in all three beverages and increased the bioaccessibility of ascorbic acid. With regard to the food matrix, α-tocopherol and ascorbic acid bioaccessibility was greatest in JW beverages and lowest in JSy beverages, whereas no significant differences were found among the three beverages in terms of carotenoid bioaccessibility. HPP-treated samples showed higher tocopherol and carotenoid bioaccessibility than TT-treated samples, thus indicating that HPP combined with a milk matrix positively modulates the bioaccessibility of certain types of bioactive components of food, mainly those of a lipophilic nature.

Phospholipids in Human Milk and Infant Formulas: Benefits and Needs for Correct Infant Nutrition

The composition of human milk has served as a basis for the development of infant formulas, which are used when breastfeeding is not possible. Among the human milk nutrients, 50% of the total energetic value corresponds to fat, with a high level of fatty acids and 0.2–2.0% present in the form of phospholipids (PLs). The PL contents and fatty acid distribution in PL species have been investigated as bioactive elements for the production of infant formulas, since they offer potential benefits for the optimum growth and health of the newborn infant. The differences in the amount of PLs and in fatty acid distribution in PL species between human milk and infant formulas can imply biologically significant differences for newborn infants fed with infant formulas versus human milk–mainly due to the greater proportion of sphingomyelin with respect to phosphatidylcholine in infant formulas. The limited information referred to the characterization of fatty acid distribution in PL species in infant formulas or in ingredients used to enrich them merits further research in order to obtain products with benefits similar to those of human milk in terms of infant growth, visual acuity, and neurological development. The present review establishes the scientific basis for helping to adjust formulations to the requirements of infant nutrition.

Plant sterols and antioxidant parameters in enriched beverages: storage stability.

Plant sterols (PS) stability, antioxidant parameters, and color were studied during 6 months of storage at 4, 24, and 37 °C in three PS-enriched functional beverages. Beverages were skimmed milk with fruit juice and PS (MFJPS), fruit juice and PS (FJPS), and skimmed milk with PS (MPS). No loss in total PS content occurred during storage observing the same values at any given storage time point. Total carotenoids decreased 36% with storage at two months and then remained stable. Total polyphenols showed fluctuations throughout the storage, remaining stable at 6 months and reaching initial values. The antioxidant capacity (TEAC method) increased 18% at 6 months, and there was an increase in color over time and temperature, probably due to Maillard reaction compound formation. The increase in total antioxidant capacity might have helped PS maintenance throughout storage, these beverages being a good PS source even after 6 months of storage.

Iron bioavailability in fortified fruit beverages using ferritin synthesis by Caco-2 cells.

The bioavailability of iron from fortified fruit beverages was estimated by an in vitro system including enzymatic digestion, iron uptake by Caco-2 cells, and ferritin formation determined via an enzyme immunoassay (ELISA). Thus, the aim of the present study was to assess iron bioavailability as influenced by the presence of known dietary promoter and inhibitory factors in fortified fruit beverages containing iron and/or zinc and/or skimmed milk. No negative effect ( p > 0.05) derived from micronutrient interaction can be ascribed to zinc supplementation on iron availability. Besides, the presence of caseinophosphopeptides derived from casein hydrolysis during digestion may confer enhancing effects on iron absorption in samples with milk added with respect to nonadded samples ( p < 0.05). Therefore, from a nutritional point of view, individuals in need of optimal iron absorption may choose dairy samples to ensure optimal iron bioavailability.

Impact of Fruit Beverage Consumption on the Antioxidant Status in Healthy Women

Background: Epidemiologic studies suggest that antioxidant-rich foods might reduce the risk of cancer and cardiovascular diseases. Aim: To test the health-protective potential of three fruit beverages, Fb (grape-orange-apricot), FbM (Fb with skimmed milk) and FbMFe [FbM + Fe(II)], in healthy women. Methods: The influence of fruit beverage consumption (500 ml/day) upon serum antioxidant capacity determined by ORAC and TEAC methods and erythrocyte superoxide dismutase (SOD) activity was assessed in 32 healthy female volunteers. In the intervention study, each subject received the fruit beverages during three periods (3 weeks for Fb and FbM, and 12 weeks in the case of FbMFe), with a 2-week washout period between treatments. Results: Intake of fruit beverages does not improve total antioxidant capacity. However, the induction of SOD found after fruit beverage consumption may be more effective than the effects of antioxidants present in these beverages, which can only stoichiometrically scavenge reactive species derived from oxidative stress. Conclusion: Iron added to FbM (FbMFe) showed induction of SOD activity, with no prooxidant effect, and could constitute a complementary source of iron, because the regular consumption of FbMFe may be beneficial for women of fertile age.

Dietary phytochemicals in the protection against oxysterol-induced damage

The intake of fruits and vegetables is associated with reduced incidence of many chronic diseases. These foods contain phytochemicals that often possess antioxidant and free radical scavenging capacity and show anti-inflammatory action, which are also the basis of other bioactivities and health benefits, such as anticancer, anti-aging, and protective action for cardiovascular diseases, diabetes mellitus, obesity and neurodegenerative disorders. Many factors can be included in the etiopathogenesis of all of these multifactorial diseases that involve oxidative stress, inflammation and/or cell death processes, oxysterols, i.e. cholesterol oxidation products (COPs) as well as phytosterol oxidation products (POPs), among others. These oxidized lipids result from either spontaneous and/or enzymatic oxidation of cholesterol/phytosterols on the steroid nucleus or on the side chain and their critical roles in the pathophysiology of the abovementioned diseases has become increasingly evident. In this context, many studies investigated the potential of dietary phytochemicals (polyphenols, carotenoids and vitamins C and E, among others) to protect against oxysterol toxicity in various cell models mimicking pathophysiological conditions. This review, summarizing the mechanisms involved in the chemopreventive effect of phytochemicals against the injury by oxysterols may constitute a step forward to consider the importance of preventive strategies on a nutritional point of view to decrease the burden of many age-related chronic diseases.

Impact of Lipid Components and Emulsifiers on Plant Sterols Bioaccessibility from Milk-Based Fruit Beverages

Sterol bioaccessibility (BA) of three plant sterol (PS)-enriched milk-based fruit beverages (MFb) with different fat contents (1.1-2.4%), lipid sources (animal or vegetable), and without or with emulsifiers (whey proteins enriched with milk fat globule membrane (MFGM) or soy lecithin) was evaluated after simulated gastrointestinal digestion. The BA of total PS followed the order 31.4% (MFbM containing milk fat and whey proteins enriched with MFGM) = 28.2% (MFbO containing extra virgin olive oil and soy lecithin) > 8.7% (MFb without fat addition). Total and individual PS content in the bioaccessible fractions followed the order MFbM > MFbO > MFb. Consequently, formulation with MFGM is proposed in beverages of this kind to ensure optimum bioavailability of PS. Our results suggest that the BA of PS is influenced by the type and quantity of fat and the emulsifier type involved.

Influence of orange cultivar and mandarin postharvest storage on polyphenols, ascorbic acid and antioxidant activity during gastrointestinal digestion

Polyphenols, ascorbic acid content and antioxidant activity of two sweet oranges (Navel-N and Cara Cara-CC) and mandarin (Clementine-M) as well as their bioaccessibilities were evaluated in pulps and compared to those in fresh juice. Thus, pulps of oranges and mandarins displayed higher hesperidin (HES), narirutin (NAR), total flavonoids (TF), total phenols (TP) and antioxidant activity (AAC) than their corresponding juices. Also, CC products presented higher bioactive compounds content than N ones. Bioaccessibility of bioactive compounds and AAC were higher in pulps of both oranges and mandarin than in their corresponding juices. Oranges (N and CC) pulps and juices presented higher bioaccessibilities than mandarin ones. The postharvest storage of mandarin at 12°C during 5weeks not only produced a significant increase of the bioactive compounds but also an increase of their bioaccessibility. The bioaccessibility of Citrus bioactive compounds is necessary for calculating more accurately their daily intake amount.