Sergio Montserrat-de la Paz

Membrane composition and dynamics: A target of bioactive virgin olive oil constituents☆

The endogenous synthesis of lipids, which requires suitable dietary raw materials, is critical for the formation of membrane bilayers. In eukaryotic cells, phospholipids are the predominant membrane lipids and consist of hydrophobic acyl chains attached to a hydrophilic head group. The relative balance between saturated, monounsaturated, and polyunsaturated acyl chains is required for the organization and normal function of membranes. Virgin olive oil is the richest natural dietary source of the monounsaturated lipid oleic acid and is one of the key components of the healthy Mediterranean diet. Virgin olive oil also contains a unique constellation of many other lipophilic and amphipathic constituents whose health benefits are still being discovered. The focus of this review is the latest evidence regarding the impact of oleic acid and the minor constituents of virgin olive oil on the arrangement and behavior of lipid bilayers. We highlight the relevance of these interactions to the potential use of virgin olive oil in preserving the functional properties of membranes to maintain health and in modulating membrane functions that can be altered in several pathologies. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cells Physiology, Pathology and Therapy.

The sterols isolated from Evening Primrose oil modulate the release of proinflammatory mediators

Evening Primrose oil is a natural product extracted by cold-pressed from Oenothera biennis L. seeds. The unsaponifiable matter of this oil is an important source of interesting minor compounds, like long-chain fatty alcohols, sterols and tocopherols. In the present study, sterols were isolated from the unsaponifiable matter of Evening Primrose oil, and the composition was identified and quantified by GC and GC-MS. The major components of sterols fraction were β-Sitosterol and campesterol. We investigated the ability of sterols from Evening Primrose oil to inhibit the release of different proinflammatory mediators in vitro by murine peritoneal macrophages stimulated with lipopolysaccharide. Sterols significantly and dose-dependently decreased nitric oxide production. Western blot analysis showed that nitric oxide reduction was a consequence of the inhibition of inducible nitric oxide synthetase expression. Sterols also reduced tumor necrosis factor-α, interleukine 1β and tromboxane B₂. However, sterols did not reduce prostaglandin E₂. The reduction of eicosanoid release was related to the inhibition of cyclooxygenase-2 expression. These results showed that sterols may have a protective effect on some mediators involved in inflammatory damage development, suggesting its potential value as a putative functional component of Evening Primrose oil.

Niacin and its metabolites as master regulators of macrophage activation

Niacin is a broad-spectrum lipid-regulating drug used for clinical therapy of chronic high-grade inflammatory diseases. However, the mechanisms by which either niacin or the byproducts of its catabolism ameliorate these inflammatory diseases are not clear yet. Human circulating monocytes and mature macrophages were used to analyze the effects of niacin and its metabolites (NAM, NUA and 2-Pyr) on oxidative stress, plasticity and inflammatory response by using biochemical, flow cytometry, quantitative real-time PCR and Western blot technologies. Niacin, NAM and 2-Pyr significantly decreased ROS, NO and NOS2 expression in LPS-treated human mature macrophages. Niacin and NAM skewed macrophage polarization toward antiinflammatory M2 macrophage whereas a trend toward proinflammatory M1 macrophage was noted following treatment with NUA. Niacin and NAM also reduced the inflammatory competence of LPS-treated human mature macrophages and promoted bias toward antiinflammatory CD14+CD16++ nonclassical human primary monocytes. This study reveals for the first time that niacin and its metabolites possess antioxidant, reprogramming and antiinflammatory properties on human primary monocytes and monocyte-derived macrophages. Our findings imply a new understanding of the mechanisms by which niacin and its metabolites favor a continuous and gradual plasticity process in the human monocyte/macrophage system.

Acute effects of dietary fatty acids on osteclastogenesis via RANKL/RANK/OPG system

SCOPE Postprandial state is directly linked with chronic diseases. We hypothesized that dietary fats may have acute effects on health status by modulating osteoclast differentiation and activation in a fatty acid-dependent manner. METHODS AND RESULTS In healthy subjects, a fat-enriched meal increased plasma levels of the RANKL (receptor activator of nuclear factor κB ligand)/OPG (osteoprotegerin) ratio (SFAs > MUFAs = PUFAs) in the postprandial state. Postprandial TRL-SFAs enhanced tartrate-resistant acid phosphatase (TRAP) activity and the expression of osteoclast marker genes (TRAP, OSCAR, RANK, and CATHK) while downregulated the expression of OPG gene in human monocyte-derived osteoclasts. These effects were not observed with monounsaturated fatty acid (MUFA)-enriched postprandial triglyceride-rich lipoproteins (TRLs). Moreover, postprandial TRL-SFAs increased the release of osteoclastogenic cytokines (TNF-α, IL-1β, and IL-6) meanwhile TRL-MUFAs and TRL-PUFAs increased the release of anti-osteoclastogenic cytokines (IL-4 and IL-10) in the medium of human monocyte-derived osteoclasts. CONCLUSION For the first time, we show that postprandial TRLs are metabolic entities with osteoclastogenic activity and that this property is related to the type of dietary fatty acid in the meal. The osteoclastogenic potency was as follows: SFAs >>> MUFAs = PUFAs. These exciting findings open opportunities for developing nutritional strategies with olive oil as the principal dietary source of MUFAs, notably oleic acid, to prevent development and progression of osteoclast-related diseases.

Exogenous fatty acids and niacin on acute prostaglandin D2 production in human myeloid cells

Niacin activates HCA2 receptor that results in the release of PGD2. However, little is known on PGD2-producing cells and the role of fatty acids. Notably M-CSF macrophages exhibited a timely dependent PGD2 production upon niacin challenge. Short pretreatment of M-CSF macrophages with autologous postprandial TRLs induced the down-regulation of HCA2 gene and up-regulation of genes encoding COX1 and COX2 enzymes in a fatty acid-dependent manner. These effects were paralleled by a higher PGD2 production with postprandial TRL-SFAs. The niacin-mediated transcriptional activity of all genes involved in PGD2 biosynthesis was desensitized in a time-dependent manner by postprandial TRLs, leading to a decreased PGD2 release. In vivo, the net excursions of PGD2 in plasma followed similar fatty acid-dependent patterns as those found for PGD2 release in vitro. The predominant fatty acid class in the diet acutely modulates PGD2 biosynthetic pathway both in vitro and in vivo.

Virgin Olive Oil and Hypertension

The incidence of high blood pressure (BP) along with other cardiovascular (CV) risk factors on human health has been studied for many years. These studies have proven a link between unhealthy dietary habits and sedentary lifestyle with the onset of hypertension, which is a hallmark of CV and cerebrovascular diseases. The Mediterranean diet, declared by the UNESCO as an Intangible Cultural Heritage since 2013, is rich in vegetables, legumes, fruits and virgin olive oil. Thanks to its many beneficial effects, including those with regard to lowering BP, the Mediterranean diet may help people from modern countries to achieve a lower occurrence of CV disease. Data from human and animal studies have shown that the consumption of virgin olive oil shares most of the beneficial effects of the Mediterranean diet. Virgin olive oil is the only edible fat that can be consumed as a natural fruit product with no additives or preservatives, and contains a unique constellation of bioactive entities, namely oleic acid and minor constituents. In this review, we summarize what is known about the effects of virgin olive oil on hypertension.

Validation and additional support for an experimental animal model of fibromyalgia.

Abstract Objectives. In the current study, we have evaluated the intermittent cold stress (ICS) induction in mice, in order to validate and optimize its utility as a fibromyalgia-like model. Methods. Twenty-four mice of 5-week old, female Swiss, weighing 18–22 g were used for the experiments. These mice were divided into three groups of eight animals per group [health control group (control), ICS group (ICS), and Gabapentin group (GBP)]. When in-vivo tests were completed, we proceeded to isolation and culture of peritoneal macrophages in order to determine the effects of the ICS on the release of proinflammatory mediators. Results. The results showed that this model is suitable to induce mechanical allodynia, thermal allodynia, and hyperalgesia. It is also able to reproduce behavioral changes related to cognitive disturbances, anxiety, and depression. Besides, ICS model might increase the inflammatory response in LPS-macrophages stimulated from stressed mice. Conclusions. Our results show that ICS is a useful animal model to assess hypothesis about underlying mechanisms involved in the development of fibromyalgia as well as to evaluate possible future therapies.

The effects of exogenous fatty acids and niacin on human monocyte-macrophage plasticity

SCOPE Macrophage plasticity allows adapting to different environments, having a dual activity in inflammatory-related diseases. Our hypothesis is that the type of dietary fatty acids into human postprandial triglyceride-rich lipoproteins (TRLs), alone or in combination with niacin (vitamin B3), could modulate the plasticity of monocytes-macrophages. METHODS AND RESULTS We isolated TRLs at the postprandial peak from blood samples of healthy volunteers after the ingestion of a meal rich in saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) or MUFAs plus omega-3 long-chain polyunsaturated fatty acids (LCPUFAs). Autologous monocytes isolated at fasting were first induced to differentiate into naïve macrophages. We observed that postprandial TRL-MUFAs, particularly in combination with niacin, enhance competence to monocytes to differentiate and polarise into M2 macrophages. Postprandial TRL-SFAs made polarised macrophages prone to an M1 phenotype. In contrast to dietary SFAs, dietary MUFAs in the meals plus immediate-release niacin primed circulating monocytes for a reduced postprandial pro-inflammatory profile. CONCLUSION Our study underlines a role of postprandial TRLs as a metabolic entity in regulating the plasticity of the monocyte-macrophage lineage and also brings an understanding of the mechanisms by which dietary fatty acids are environmental factors fostering the innate immune responsiveness in humans.

Leukocyte Overexpression of Intracellular NAMPT Attenuates Atherosclerosis by Regulating PPARγ-Dependent Monocyte Differentiation and Function

Objective— Extracellular nicotinamide phosphoribosyltransferase (eNAMPT) mediates inflammatory and potentially proatherogenic effects, whereas the role of intracellular NAMPT (iNAMPT), the rate limiting enzyme in the salvage pathway of nicotinamide adenine dinucleotide (NAD)+ generation, in atherogenesis is largely unknown. Here we investigated the effects of iNAMPT overexpression in leukocytes on inflammation and atherosclerosis. Approach and Results— Low-density lipoprotein receptor–deficient mice with hematopoietic overexpression of human iNAMPT (iNAMPThi), on a western type diet, showed attenuated plaque burden with features of lesion stabilization. This anti-atherogenic effect was caused by improved resistance of macrophages to apoptosis by attenuated chemokine (C–C motif) receptor 2-dependent monocyte chemotaxis and by skewing macrophage polarization toward an anti-inflammatory M2 phenotype. The iNAMPThi phenotype was almost fully reversed by treatment with the NAMPT inhibitor FK866, indicating that iNAMPT catalytic activity is instrumental in the atheroprotection. Importantly, iNAMPT overexpression did not induce any increase in eNAMPT, and eNAMPT had no effect on chemokine (C–C motif) receptor 2 expression and promoted an inflammatory M1 phenotype in macrophages. The iNAMPT-mediated effects at least partly involved sirtuin 1–dependent molecular crosstalk of NAMPT and peroxisome proliferator–activated receptor &ggr;. Finally, iNAMPT and peroxisome proliferator–activated receptor &ggr; showed a strong correlation in human atherosclerotic, but not healthy arteries, hinting to a relevance of iNAMPT/peroxisome proliferator–activated receptor &ggr; pathway also in human carotid atherosclerosis. Conclusions— This study highlights the functional dichotomy of intracellular versus extracellular NAMPT, and unveils a critical role for the iNAMPT–peroxisome proliferator–activated receptor &ggr; axis in atherosclerosis.

Mitraphylline inhibits lipopolysaccharide-mediated activation of primary human neutrophils

BACKGROUND Mitraphylline (MTP) is the major pentacyclic oxindolic alkaloid presented in Uncaria tomentosa. It has traditionally been used to treat disorders including arthritis, heart disease, cancer, and other inflammatory diseases. However, the specific role of MTP is still not clear, with more comprehensivestudies, our understanding of this ancient herbal medicine will continue growing. HYPOTHESIS/PURPOSE Some studies provided its ability to inhibit proinflamatory cytokines, such as TNF-α, through NF-κB-dependent mechanism. TNF-α primes neutrophils and modulates phagocytic and oxidative burst activities in inflammatory processes. Since, neutrophils represent the most abundant pool of leukocytes in human blood and play a crucial role in inflammation, we aimed to determine the ability of MTP to modulate neutrophil activation and differentially regulate inflammatory-related cytokines. METHODS To determine the mechanism of action of MTP, we investigated the effects on LPS-activated human primary neutrophils responses including activation surface markers by FACS and the expression of inflammatory cytokines, measured by real time PCR and ELISA. RESULTS Treatment with MTP reduced the LPS-dependent activation effects. Activated neutrophils (CD16(+)CD62L(-)) diminished after MTP administration. Moreover, proinflamatory cytokines (TNF-α, IL-6 or IL-8) expression and secretion were concomitantly reduced, similar to basal control conditions. CONCLUSION Taken together, our results demonstrate that MTP is able to elicit an anti-inflammatory response that modulates neutrophil activation contributing to the attenuation of inflammatory episodes. Further studies are need to characterize the mechanism by which MTP can affect this pathway that could provide a means to develop MTP as new candidate for inflammatory disease therapies.