HDL anti-inflammatory function is impaired and associated with high SAA1 and low APOA4 levels in aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating disease with high morbidity and mortality rates. Within 24 hours after aSAH, monocytes are recruited and enter the subarachnoid space, where they mature into macrophages, increasing the inflammatory response and contributing, along with other factors, to delayed neurological dysfunction and poor outcomes. High-density lipoproteins (HDL) are lipid-protein complexes that exert anti-inflammatory effects but under pathological conditions undergo structural alterations that have been associated with loss of functionality. Plasma HDL were isolated from patients with aSAH and analyzed for their anti-inflammatory activity and protein composition. HDL isolated from patients lost the ability to prevent VCAM-1 expression in endothelial cells (HUVEC) and subsequent adhesion of THP-1 monocytes to the endothelium. Proteomic analysis showed that HDL particles from patients had an altered composition compared to those of healthy subjects. We confirmed by western blot that low levels of apolipoprotein A4 (APOA4) and high of serum amyloid A1 (SAA1) in HDL were associated with the lack of anti-inflammatory function observed in aSAH. Our results indicate that the study of HDL in the pathophysiology of aSAH is needed, and functional HDL supplementation could be considered a novel therapeutic approach to the treatment of the inflammatory response after aSAH.

Dietary Influence on Nutritional Epidemiology, Public Health and Our Lifestyle

This Special Issue of Nutrients "Dietary Influence on Nutritional Epidemiology, Public Health and Our Lifestyle", includes nine original articles and one systematic review related to the associations between some dietary patterns, lifestyle, and socio-demographic factors, analyzed either separately or in combination, with the risk and management of cardiovascular diseases and mental health problems, such as depression and dementia [...].

New evidence for dietary fatty acids in the neutrophil traffic between the bone marrow and the peripheral blood

•

SFAs but not MUFAs boosted neutrophils both in bone marrow and blood.

•

SFAs were strong inducers of bone marrow neutrophil apoptosis and inflammation.

•

CXCL2-CXCR2 axis engaged in fatty-acid-mediated navigation of neutrophils.

•

Fatty-acid-dependent neutrophilia occurred in a postprandial model.

Chronic administration of a high-fat diet in mice has been established to influence the generation and trafficking of immune cells such as neutrophils in the bone marrow, the dysregulation of which may contribute to a wide range of diseases. However, no studies have tested the hypothesis that a short-term, high-fat diet could early modulate the neutrophil release from bone marrow at fasting and at postprandial in response to a high-fat meal challenge, and that the predominant type of fatty acids in dietary fats could play a role in both context conditions. Based on these premises, we aimed to establish the effects of different fats [butter, enriched in saturated fatty acids (SFAs), olive oil, enriched in monounsaturated fatty acids (MUFAs), and olive oil supplemented with eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids] on neutrophil navigation from bone marrow to blood in mice. The analysis of cellular models for mechanistic understanding and of postprandial blood samples from healthy volunteers for translational purposes was assessed. The results revealed a powerful effect of dietary SFAs in promotion the neutrophil traffic from bone marrow to blood via the CXCL2-CXCR2 axis. Dietary SFAs, but not MUFAs or EPA and DHA, were also associated with increased neutrophil apoptosis and bone marrow inflammation. Similar dietary fatty-acid-induced postprandial neutrophilia was observed in otherwise healthy humans. Therefore, dietary MUFAs might preserve bone marrow health and proper migration of bone marrow neutrophils early in the course of high-fat diets even after the intake of high-fat meals.

A lupine (Lupinus angustifolious L.) peptide prevents non-alcoholic fatty liver disease in high-fat-diet-induced obese mice

Bioactive peptides are related to the prevention and treatment of many diseases. GPETAFLR is an octapeptide that has been isolated from lupine (Lupinus angustifolius L.) and shows anti-inflammatory properties. The aim of this study was to evaluate the potential activity of GPETAFLR to prevent non-alcoholic fatty liver disease (NAFLD) in high-fat-diet (HFD)-induced obese mice. C57BL/6J mice were fed a standard diet or HFD. Two of the groups fed the HFD diet were treated with GPETAFLR in drinking water at 0.5 mg kg-1 day-1 or 1 mg kg-1 day-1. To determine the ability of GPETAFLR to improve the onset and progression of non-alcoholic fatty liver disease, histological studies, hepatic enzyme profiles, inflammatory cytokine and lipid metabolism-related genes and proteins were analysed. Our results suggested that HFD-induced inflammatory metabolic disorders were alleviated by treatment with GPETAFLR. In conclusion, dietary lupine consumption can repair HFD-induced hepatic damage possibly via modifications of liver's lipid signalling pathways.

Changes in High-Density Lipoproteins Related to Outcomes in Patients with Acute Stroke

Modifications in high-density lipoprotein (HDL) particle sizes and HDL-binding proteins have been reported in stroke patients. We evaluated whether the lipoprotein profile, HDL composition and functionality were altered in stroke patients according to their clinical outcome using the modified Rankin Score at 3 months. Plasma samples were obtained from stroke patients treated with intravenous thrombolysis. Levels of cardiovascular and inflammatory markers in plasma were measured using the Human CVD Panel 1 (Milliplex^® MAP). Lipoprotein subfractions from plasma were quantified by non-denaturing acrylamide gel electrophoresis, using the Lipoprint^®-System (Quantimetrix^®), and HDLs were isolated by ultracentrifugation. Relative amounts of paraoxonase-1 (PON1) and alpha-1 anti-trypsin (AAT) in the isolated HDLs were determined by Western blot. HDL anti-inflammatory function was evaluated in human blood-brain barrier endothelial cells stimulated with 100 ng/mL TNFα, and HDL antioxidant function was evaluated via their capacity to limit copper-induced low-density lipoprotein oxidation. Stroke patients with unfavorable outcomes had a lower proportion of small-sized HDLs and increased plasma levels of E-selectin (SELE) and the intercellular adhesion molecule 1 (ICAM1). HDLs from patients with unfavorable outcomes had lower levels of PON1 and displayed a blunted capacity to reduce the expression of SELE, interleukin 8 (IL8) and the monocyte chemoattractant protein-1 (MCP1) mRNA induced by TNFα in endothelial cells. These HDLs also had a reduced antioxidant capacity relative to HDLs from healthy donors. In conclusion, an increased ratio of large/small HDLs with impaired anti-inflammatory and antioxidant capacities was associated with unfavorable outcomes in stroke patients. Alteration of HDL functionality was mainly associated with a low amount of PON1 and high amount of AAT.

Extra-Virgin Olive Oil with Natural Phenolic Content Exerts an Anti-Inflammatory Effect in Adipose Tissue and Attenuates the Severity of Atherosclerotic Lesions in Ldlr-/-.Leiden Mice

SCOPE

The present study investigates the effect of olive oils with different phenolic content in high-fat diets (HFDs) on hypertrophy and inflammation in adipose tissue and associated atherosclerosis, in the context of obesity.

METHODS AND RESULTS

Ldlr-/-.Leiden mice were fed three different HFDs for 32 weeks and were compared with mice fed the standard low-fat diet (LFD). The different fats provided in the HFDs were lard (HFD-L), extra-virgin olive oil (EVOO; 79 mg kg^-1 of phenolic compounds, HFD-EVOO), or EVOO rich in phenolic compounds (OL, 444 mg kg^-1 of phenolic compounds, HFD-OL). All HFD-fed mice became obese, but only HFD-L-induced adipocyte hypertrophy. HFD-EVOO mice exhibited the greatest levels of Adiponectin in adipose tissue and presented atherosclerotic lesions similar to the LFD group, with a very low count of monocyte/macrophage compared with HFD-L and HFD-OL mice. Enrichment of the phenolic content of olive oil reduced the secretion of nitrites/nitrates in the aorta, but atherosclerosis was not attenuated in HFD-OL mice compared to other HFD mice.

CONCLUSION

Consumption of olive oil with a natural content of phenolic compounds attenuates adipose tissue hypertrophy and inflammation and exerts antiatherosclerotic effects in mice. A higher phenolic content of olive oil did not provide further benefits in the prevention of atherosclerosis.

Molecular dynamics simulation of the behaviour of water in nano-confined ionic liquid-water mixtures

This work describes the behaviour of water molecules in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid under nanoconfinement, between graphene sheets. By means of molecular dynamics simulations, the adsorption of water molecules at the graphene surface is studied. A depletion of water molecules in the vicinity of the neutral and negatively charged graphene surfaces, and their adsorption at the positively charged surface are observed in line with the preferential hydration of the ionic liquid anions. The findings are appropriately described using a two-level statistical model. The confinement effect on the structure and dynamics of the mixtures is thoroughly analyzed using the density and the potential of mean force profiles, as well as by the vibrational densities of the states of water molecules near the graphene surface. The orientation of water molecules and the water-induced structural transitions in the layer closest to the graphene surface are also discussed.

Structural and electronic properties of zigzag InP nanoribbons with Stone-Wales type defects

By means of density-functional-theoretic calculations, we investigate the structural and electronic properties of a hexagonal InP sheet and of hydrogen-passivated zigzag InP nanoribbons (ZInPNRs) with Stone-Wales (SW)-type defects. Our results show that the influence of this kind of defect is not limited to the defected region but it leads to the formation of ripples that extend across the systems, in keeping with the results obtained recently for graphene and silicene sheets. The presence of SW defects in ZInPNRs causes an appreciable broadening of the band gap and transforms the indirect-bandgap perfect ZInPNR into a direct-bandgap semiconductor. An external transverse electric field, regardless of its direction, reduces the gap in both the perfect and defective ZInPNRs.

Clustering effects on postprandial insulin secretion and sensitivity in response to meals with different fatty acid compositions

Dietary fatty acids play a role in glucose homeostasis. The aim of this study was to assess the individual relationship between dietary saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids with postprandial β-cell function and insulin sensitivity in subjects with normal and high fasting triglycerides. We assessed postprandial β-cell function (by the insulinogenic index and the ratio of the insulin to glucose areas under the time-concentration curve) and insulin sensitivity (by the oral glucose and the minimal model insulin sensitivity indices) over four nonconsecutive, randomly assigned, high-fat meals containing a panel of SFA (palmitic and stearic acids), MUFA (palmitoleic and oleic acids) and PUFA (linoleic and α-linolenic acids) in 14 subjects with normal and in 14 subjects with high fasting triglycerides. The proportions of each fatty acid in the meals and the values for surrogate measures of postprandial β-cell function and insulin sensitivity were subjected to a Pearson correlation and hierarchical cluster analysis, which revealed two classes of dietary fatty acids for regulating postprandial glucose homeostasis. We successfully discriminated the adverse effects of SFA palmitic acid from the beneficial effects of MUFA oleic acid on postprandial β-cell function (r ≥ 0.84 for SFA palmitic acid and r ≥ -0.71 for MUFA oleic acid; P < 0.05) and insulin sensitivity (r ≥ -0.92 for SFA palmitic acid and r ≥ 0.89 for MUFA oleic acid; P < 0.001) both in subjects with normal and high fasting triglycerides. In conclusion, dietary MUFA oleic acid, in contrast to SFA palmitic acid, favours the tuning towards better postprandial glycaemic control in subjects with normal and high fasting triglycerides.

Postprandial triglyceride-rich lipoproteins regulate perilipin-2 and perilipin-3 lipid-droplet-associated proteins in macrophages

Lipid accumulation in macrophages contributes to atherosclerosis. Within macrophages, lipids are stored in lipid droplets (LDs); perilipin-2 and perilipin-3 are the main LD-associated proteins. Postprandial triglyceride (TG)-rich lipoproteins induce LD accumulation in macrophages. The role of postprandial lipoproteins in perilipin-2 and perilipin-3 regulation was studied. TG-rich lipoproteins (TRLs) induced the levels of intracellular TGs, LDs and perilipin-2 protein expression in THP-1 macrophages and in Apoe(-/-) mice bone-marrow-derived macrophages with low and high basal levels of TGs. Perilipin-3 was only synthesized in mice macrophages with low basal levels of TGs. The regulation was dependent on the fatty acid composition of the lipoproteins; monounsaturated and polyunsaturated fatty acids (PUFAs) more strongly attenuated these effects compared with saturated fatty acids. In THP-1 macrophages, immunofluorescence microscopy and freeze-fracture immunogold labeling indicated that the lipoproteins translocated perilipin-3 from the cytoplasm to the LD surface; only the lipoproteins that were rich in PUFAs suppressed this effect. Chemical inhibition showed that lipoproteins induced perilipin-2 protein expression through the peroxisome proliferator-activated nuclear receptor (PPAR) PPARα and PPARγ pathways. Overall, our data indicate that postprandial TRLs may be involved in atherosclerotic plaque formation through the regulation of perilipin-2 and perilipin-3 proteins in macrophages. Because the fatty acid composition of the lipoproteins is dependent on the type of fat consumed, the ingestion of olive oil, which is rich in monounsaturated fatty acids, and fish oil, which is rich in omega-3 fatty acids, can be considered a good nutritional strategy to reduce the risk of atherosclerosis by LD-associated proteins decrease.

The effects of dietary fatty acids on the postprandial triglyceride-rich lipoprotein/apoB48 receptor axis in human monocyte/macrophage cells

Intestinally produced triglyceride-rich lipoproteins (TRL) play an important role in the progression of atherosclerosis. In this study, we investigated the relevance of monounsaturated fatty acid (MUFA) and saturated fatty acid (SFA) in postprandial TRL in affecting the transcriptional activity of the apolipoprotein-B48 receptor (ApoB48R) and its functionality in human monocyte/macrophage cells. Healthy male volunteers were administered four standardized high-fat meals containing butter, high-palmitic sunflower oil, olive oil (ROO) or a mixture of vegetable and fish oils (50 g/m(2) body surface area) to obtain a panel of postprandial TRL with gradual MUFA oleic acid-to-SFA palmitic acid ratios. The increase in this ratio was linearly associated with a decrease of ApoB48R up-regulation and lipid accumulation in THP-1 and primary monocytes. ApoB48R mRNA levels and intracellular triglycerides were also lower in the monocytes from volunteers after the ingestion of the ROO meal when compared to the ingestion of the butter meal. In THP-1 macrophages, the increase in the MUFA oleic acid-to-SFA palmitic acid ratio in the postprandial TRL was linearly correlated with an increase in ApoB48R down-regulation and a decrease in lipid accumulation. We also revealed that the nuclear receptor transcription factors PPARα, PPARβ/δ, and PPARγ and the PPAR-RXR transcriptional complex were involved in sensing the proportion of MUFA oleic acid and SFA palmitic acid, and these were also involved in adjusting the transcriptional activity of ApoB48R. The results of this study support the notion that MUFA-rich dietary fats may prevent excessive lipid accumulation in monocyte/macrophage cells by targeting the postprandial TRL/ApoB48R axis.

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 Cell's Physiology, Pathology and Therapy.

p38 MAPK protects human monocytes from postprandial triglyceride-rich lipoprotein-induced toxicity

Postprandial triglyceride (TG)-rich lipoproteins (TRLs) transport dietary fatty acids through the circulatory system to satisfy the energy and structural needs of the tissues. However, fatty acids are also able to modulate gene expression and/or induce cell death. We investigated the underlying mechanism by which postprandial TRLs of different fatty acid compositions can induce cell death in human monocytes. Three types of dietary fat [refined olive oil (ROO), high-palmitic sunflower oil (HPSO), and butter] with progressively increasing SFA:MUFA ratios (0.18, 0.41, and 2.08, respectively) were used as a source of postprandial TRLs (TRL-ROO, TRL-HPSO, and TRL-BUTTER) from healthy men. The monocytic cell line THP-1 was used as a model for this study. We demonstrated that postprandial TRLs increased intracellular lipid accumulation (31-106%), reactive oxygen species production (268-349%), DNA damage (133-1467%), poly(ADP-ribose) polymerase 1 (800-1710%) and caspase-3 (696-1244%) activities, and phosphorylation of c-Jun NH2-terminal kinase (JNK) (54 kDa, 141-288%) and p38 (24-92%). These effects were significantly greater with TRL-BUTTER, and TRL-ROO did not induce DNA damage, DNA fragmentation, or p38 phosphorylation. In addition, blockade of p38, but not of JNK, significantly decreased intracellular lipid accumulation and increased cell death in postprandial TRL-treated cells. These results suggest that in human monocytes, p38 is involved in survival signaling pathways that protect against the lipid-mediated cytotoxicity induced by postprandial TRLs that are abundant in saturated fatty acids.

Electrical conductivity of seven binary systems containing 1-ethyl-3-methyl imidazolium alkyl sulfate ionic liquids with water or ethanol at four temperatures

We present experimental measurements of specific electrical (or ionic) conductivity of seven binary systems of 1-ethyl-3-methyl imidazolium alkyl sulfate (EMIM-C(n)S) with water or ethanol. Electrical conductivity was measured at 298.15 K in all ranges of concentrations and selected mixtures also at 288.15, 308.15, and 318.15 K. The alkyl chains of the anions used are ethyl (EMIM-ES), butyl (EMIM-BS), hexyl (EMIM-HS), and, only for mixtures with ethanol, octyl (EMIM-OS). Let us note that the four ionic liquids (ILs) measured are miscible in water and ethanol at those temperatures and atmospheric pressure in all ranges of concentrations, but EMIM-OS jellifies for a given range of concentration with water. We compare the measured data in terms of the alkyl chain length and solvent nature. Data are compared with previously scarce results for these same systems and also for other aqueous and ethanol mixtures with ILs. In addition, we verify that our data fit the universal theoretical expression with no fitting parameters given by the pseudolattice-based Bahe-Varela model, except for IL concentrated mixtures. To fit well all ranges of concentrations, we add to the original equation two phenomenological terms with one fitting parameter each. Finally, we calculate the molar conductivity and fit it successfully with an expression derived from Onsager theory.

Effect of temperature and cationic chain length on the physical properties of ammonium nitrate-based protic ionic liquids

We report a systematic study of the effect of the cationic chain length and degree of hydrogen bonding on several equilibrium and transport properties of the first members of the alkylammonium nitrate protic ionic liquids (PILs) family (ethylammonium, propylammonium, and butylammonium nitrate) in the temperature range between 10 and 40 °C. These properties were observed by means of several experimental techniques, including density, surface tension, refractometry, viscosimetry, and conductimetry. The dilatation coefficients and compressibilities, as well as the Rao coefficients, were calculated, and an increase of these magnitudes with alkyl chain length was detected. Moreover, the surface entropies and enthalpies of the studied PILs were analyzed, and the temperature dependence of the surface tension was observed to be describable by means of a harmonic oscillator model with surface energies and critical temperatures that are increasing functions of the cationic chain length. Moreover, the refractive indexes were measured and the thermo-optic coefficient and Abbe numbers were calculated, and the contribution of the electrostrictive part seemed to dominate the temperature dependence of the electric polarization. The electric conductivity and the viscosity were measured and the influence of the degree of hydrogen bonding in the supercooled liquid region analyzed. Hysteresis loops were detected in freezing-melting cycles and the effect of the length of the alkyl chain of the cation on the size of the loop analyzed, showing that longer chains lead to a narrowing of the supercooled region. The temperature dependence of the conductivity was studied in the Vogel-Fulcher-Tamman (VFT) framework and the fragility indices, the effective activation energies, and the Vogel temperatures obtained. A high-temperature Arrhenius analysis was also performed, and the activation energies of conductivity and viscosity were calculated, showing that these transport processes are governed by two distinct mechanisms. The exponents of the fractional Walden rule for the different compounds were obtained. Finally, the ionicities and fragilities of the studied PILs were analyzed, proving that all the studied PILs are subionic and fragile liquids, with propylammonium nitrate showing the lowest fragility and the greater ionicity of all the studied compounds.

Triglyceride-rich lipoprotein regulates APOB48 receptor gene expression in human THP-1 monocytes and macrophages

The postprandial metabolism of dietary fats implies that the production of TG-rich lipoproteins (TRL) contributes to the progression of plaque development. TRL and their remnants cause rapid receptor-mediated monocyte/macrophage lipid engorgement via the cell surface apoB48 receptor (apoB48R). However, the mechanistic basis for apoB48 receptor (APOB48R) regulation by postprandial TRL in monocytes and macrophages is not well established. In this study, we investigated the effects of postprandial TRL from healthy volunteers on the expression of APOB48R mRNA and lipid uptake in human THP-1 monocytes and THP-1-derived macrophages. The expression of APOB48R mRNA was upregulated in THP-1 monocytes, but downregulated in THP-1-derived macrophages when treated with postprandial TRL (P < 0.05), in a dose- and time-dependent manner. TG and free cholesterol were dramatically increased in THP-1-derived macrophages (140 and 50%, respectively; P < 0.05) and in THP-1 monocytes (160 and 95%, respectively; P < 0.05). This lipid accumulation was severely decreased (~50%; P < 0.05) in THP-1-derived macrophages by small interfering RNA (siRNA) targeting of APOB48R. Using PPAR and retinoid X receptor (RXR) agonists, antagonists, and siRNA, our data indicate that PPARα, PPARγ, and RXRα are involved in postprandial TRL-induced APOB48R transcriptional regulation. Co-incubation with acyl-CoA synthetase or acyl-CoA:cholesterol acyltransferase inhibitors potentiated the effects of postprandial TRL on the expression of APOB48R mRNA in THP-1 monocytes and THP-1-derived macrophages. Our findings collectively suggest that APOB48R represents a molecular target of postprandial TRL via PPAR-dependent pathways in human THP-1 monocytes and macrophages and advance a potentially important link between postprandial metabolism of dietary fats and atherogenesis.

Dietary fatty acids linking postprandial metabolic response and chronic diseases

Chronic diseases are by far one of the main causes of mortality in the world. One of the current global recommendations to counteract disability and premature death resulting from chronic diseases is to decrease the consumption of energy-dense high-fat diets, particularly those rich in saturated fatty acids (SFA). The most effective replacement for SFA in terms of risk factor outcomes for chronic disease are polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA). The biochemical basis for healthy benefits of such a dietary pattern has been widely evaluated under fasting conditions. However, the increasing amount of data available from multiple studies suggest that the postprandial state, i.e., "the period that comprises and follows a meal", plays an important, yet underappreciated, role in the genesis of numerous pathological conditions. In this review, the potential of MUFA, PUFA, and SFA to postprandially affect selected metabolic abnormalities related to chronic diseases is discussed.

A high-fat meal promotes lipid-load and apolipoprotein B-48 receptor transcriptional activity in circulating monocytes

BACKGROUND

The postprandial metabolism of dietary fats results in the production of apolipoprotein B-48 (apoB48)-containing triglyceride-rich lipoproteins (TRLs), which cause rapid receptor-mediated macrophage lipid engorgement via the apoB48 cell surface receptor (apoB48R). Monocytes circulate together with apoB48-containing TRLs in the postprandial bloodstream and may start accumulating lipids even before their migration to tissues and differentiation to macrophages.

OBJECTIVE

We sought to determine whether circulating monocytes are equipped with apoB48R and whether, in the postprandial state, circulating monocytes accumulate lipids and modulate apoB48R transcriptional activity after intake of a high-fat meal.

DESIGN

In a crossover design, we studied the effect of a high-fat meal on fasting and postprandial concentrations of triglycerides, free fatty acids, cholesterol, and insulin in 12 healthy men. TRLs and monocytes were freshly isolated at fasting, hourly until the postprandial peak, and at the late postprandial phase. TRLs were subjected to triglycerides, apoB48, and apolipoprotein B-100 analyses; and lipid accumulation and apoB48R mRNA expression levels were measured in monocytes.

RESULTS

Monocytes showed a time-dependent lipid accumulation in response to the high-fat meal, which was paralleled by an increase in apoB48R mRNA expression levels. These effects were coincident only with an increase in apoB48-containing TRLs in the postprandial phase and were also observed ex vivo in freshly isolated monocytes incubated with apoB48-containing TRLs.

CONCLUSION

In a setting of abundant plasma apoB48-containing TRLs, these findings highlight the role of dietary fat in inducing lipid accumulation and apoB48R gene transcription in circulating monocytes.

Effects of meals rich in either monounsaturated or saturated fat on lipid concentrations and on insulin secretion and action in subjects with high fasting triglyceride concentrations

BACKGROUND

The nature of dietary fats and fasting concentrations of triglycerides affect postprandial hypertriglyceridemia and glucose homeostasis.

OBJECTIVES

The objectives were to examine the effects of meals enriched in monounsaturated fatty acids (MUFAs) or saturated fatty acids (SFAs) on postprandial lipid, glucose, and insulin concentrations and to examine the extent of β cell function and insulin sensitivity in subjects with high fasting triglyceride concentrations.

DESIGN

Fourteen men with fasting hypertriglyceridemia and normal glucose tolerance were given meals (≈10 kcal/kg body weight) containing MUFAs, SFAs, or no fat. Blood samples were collected at baseline and hourly over 8 h for analysis.

RESULTS

The high-fat meals significantly increased postprandial concentrations of triglycerides, nonesterified fatty acids, and insulin and postprandial indexes of β cell function. However, postprandial indexes of insulin sensitivity decreased significantly. These effects were significantly attenuated with MUFAs relative to SFAs.

CONCLUSIONS

MUFAs postprandially buffered β cell hyperactivity and insulin intolerance relative to SFAs in subjects with high fasting triglyceride concentrations. These data suggest that, in contrast with SFAs, MUFA-based strategies may provide cardiovascular benefits to persons at risk by limiting lipid and insulin excursions and may contribute to optimal glycemic control after meal challenges.

The flavonol isorhamnetin exhibits cytotoxic effects on human colon cancer cells

The aim of this study was to determine whether isorhamnetin, an immediate 3'-O-methylated metabolite of quercetin, affects proliferation, cell death, and the cell cycle of human colon carcinoma (HCT-116) cells. Isorhamnetin was found to be a potent antiproliferative agent in a dose- and time-dependent manner, with an IC50 of 72 μM after 48 h of incubation as estimated by MTT assay. Flow cytometry and fluorescence microscopy analysis showed that isorhamnetin exerted a stimulatory effect on apoptosis and necrosis. Isorhamnetin also increased the number of cells in G2/M phase. Serum deprivation appeared to potentiate the effects of isorhamnetin on cell death and facilitated cell cycle progression to G0/G1 phase. These results suggest that isorhamnetin might mediate inhibition of HCT-116 cell growth through the perturbation of cell cycle progression and are consistent with the notion that G2/M checkpoints could be a conserved target for flavonoids in human colon cancer cells, leading to apoptotic and necrotic death. These antiproliferative, apoptotic, necrotic, and cell cycle effects suggest that isorhamnetin may have clinically significant therapeutic and chemopreventive capabilities. To our knowledge, this is the first report of the effect of isorhamnetin on human colon cancer cells.

Nonequilibrium nanothermodynamics

Entropy production for a system outside the thermodynamic limit is formulated using Hill's nanothermodynamics, in which a macroscopic ensemble of such systems is considered. The external influence of the environment on the average nanosystem is connected to irreversible work with an explicit formula based on the Jarzynski equality. The entropy production retains its usual form as a sum of products of fluxes and forces and Onsager's symmetry principle is proven to hold for the average nanosystem, if it is assumed to be valid for the macroscopic ensemble, by two methods. The first one provides expressions that relate the coefficients of the two systems. The second gives a general condition for a system under an external force to preserve Onsager's symmetry.

Sphere to rod transitions in homologous alkylpyridinium salts: A Stauff-Klevens-type equation for the second critical micelle concentration

In the present paper, we analyze the dependence of the second critical micelle concentration (second cmc) of ionic amphiphiles on the number of atoms in the hydrocarbon molecular chain, n(c). A molecular thermodynamic model for the interaction energy between the end caps of rodlike micelles, g(N), is introduced and the linear dependence of this object on n(c) analyzed, thus leading to a Stauff-Klevens-like behavior of the second cmc. The predictions agree with previously reported data for n-alkyldimethylbenzylammonium chloride (C(n)BACl) for n-alkylpyridinium chloride (C(n)PyCl) and n-alkyltrymethylammonium bromide (C(n)TABr) at 35 degrees C. These conclusions are reinforced by the conductivity, density, and ultrasound velocity measurements of the second cmc of several C(n)PyCl (n=12, 14, 16) and n-alkylpyridinium bromides (C(n)PyBr, n=12, 14, 15, 16) presented in this paper.

Electrical conductivity of aqueous solutions of aluminum salts

We present experimental measurements of the specific electrical conductivity (sigma) in aqueous solutions of aluminum salts at different temperatures, covering all salt concentrations from saturation to infinite dilution. The salts employed were AlCl(3), AlBr(3), AlI(3), and Al(NO(3))(3), which present a 1:3 relationship between the electrical charges of anion and cation. In addition, we have measured the density in all ranges of concentrations of the four aqueous electrolyte solutions at 298.15 K. The measured densities show an almost linear behavior with concentration, and we have fitted it to a second order polynomial with very high degree of approximation. The measurement of the specific conductivity at constant temperature reveals the existence of maxima in the conductivity vs concentration curves at molar concentrations around 1.5M for the three halide solutions studied, and at approximately 2M for the nitrate. We present a theoretical foundation for the existence of these maxima, based on the classical Debye-Hu ckel-Onsager hydrodynamic mean-field framework for electrical transport and its high concentration extensions, and also a brief consideration of ionic frictional coefficients using mode-coupling theory. We also found that the calculated values of the equivalent conductance vary in an approximately linear way with the square root of the concentration at concentrations as high as those where the maximum of sigma appears. Finally, and for completeness, we have measured the temperature dependence of the electrical conductivity at selected concentrations from 283 to 353 K, and performed a fit to an exponential equation of the Vogel-Fulcher-Tamman type. The values of the calculated temperatures of null mobility of the four salts are reported.

Adsorption of an amphiphilic penicillin onto human serum albumin: characterisation of the complex

The complex formed by the interaction of the amphiphilic penicillin drug nafcillin and human serum albumin (HSA) in water at 25 degrees C has been characterised using a range of physicochemical techniques. Measurements of the solution conductivity and the electrophoretic mobility of the complexes have shown an ionic adsorption of the drug on the protein surface leading to a surface saturation at a nafcillin concentration of 0.012 mmol kg(-1) and subsequent formation of drug micelles in solutions of higher nafcillin concentration. Measurements of the size of the complex and the thickness of the adsorbed layer by static and dynamic light scattering have shown a gradual change in hydrodynamic radius of the complex with increasing drug concentration typical of a saturation rather than a denaturation process, the magnitude of the change being insufficient to account for any appreciable extension or unfolding of the HSA molecule. The interaction potential between the HSA/nafcillin complexes, and the stability of the complexes were determined from the dependence of diffusion coefficients on protein concentration by application of the DLVO colloidal stability theory. The results indicate decreasing stability of the colloidal dispersion of the drug/protein complexes with an increase in the concentration of added drug.

TNFalpha induces NFkappaB/p50 in association with the growth and morphogenesis of normal and transformed rat mammary epithelial cells

In contrast to the cytotoxic or cytostatic effect of TNFalpha on many breast cancer cell lines, TNFalpha stimulates growth and morphogenesis of normal rat mammary epithelial cells (MEC). The present studies were carried out to determine whether there are intrinsic differences between normal and malignant MEC which may explain the differing responsiveness to TNFalpha. Freshly isolated rat MEC organoids from normal mammary gland or 1-methyl-1-nitrosourea-induced mammary tumors were treated with TNFalpha for 21 days. Unexpectedly, TNFalpha stimulated growth and morphogenesis of both normal and transformed MEC in primary culture, although in transformed cells its effects were delayed and the majority of the colonies were histologically abnormal, with multiple cell layers and no lumen. Since NFkappaB is a key mediator of TNFalpha action and has been implicated in carcinogenesis, the expression of the p50, p52, p65, and c-rel NFkappaB proteins in normal and transformed MEC was determined. Expression of p52 was significantly reduced in tumor cells, and p50 was absent, although its putative precursor, p105 was abundant. There were no changes in the levels of p65 or c-rel. TNFalpha induced a pronounced and sustained increase of a p50 homodimeric NFkappaB/DNA complex in both normal and transformed MEC. However, in transformed MEC, NFkappaB binding was initially undetectable but then increased in response to TNFalpha. Thus, NFkappaB expression and DNA binding activity are altered during mammary carcinogenesis. In addition, the significant increase in NFkappaB/p50 DNA-binding was temporally coincident with TNFalpha-induced growth and morphogenesis, suggesting that it may play a significant role in both normal development and carcinogenesis.

Selective changes in EGF receptor expression and function during the proliferation, differentiation and apoptosis of mammary epithelial cells

Epidermal growth factor (EGF) is a multifunctional regulator of mammary epithelial cells (MEC) that transduces its signals through the EGF receptor (EGFR). To clarify the role of the EGFR in the mammary gland, EGFR expression, localization and function were examined during different developmental stages in rats. Immunoblot analysis demonstrated high levels of EGFR during puberty, pregnancy and involution as well as at sexual maturity, and low levels throughout lactation. An immunohistochemical assay was used to show that EGFR was distinctly expressed in a variety of cell types throughout mammary glands from virgin rats and rats during pregnancy and involution, and was down-regulated in all cell types throughout lactation. To examine the relationship between EGFR expression and function, primary MEC were cultured under conditions that induced physiologically relevant growth, morphogenesis and lactogenesis. Cultured MEC expressed an in vivo-like profile of EGFR. EGFR was high in immature MEC, down-regulated in functionally differentiated MEC, and then up-regulated in terminally differentiated and apoptotic MEC. An inhibitor of the tyrosine kinase domain of EGFR was used to demonstrate that EGFR signaling was required for growth and differentiation of immature MEC, and for survival of terminally differentiated MEC, but not for maintaining functional differentiation.

The epidermal growth factor receptor is not required for tumor necrosis factor-alpha action in normal mammary epithelial cells

Our laboratory has shown that tumor necrosis factor-alpha (TNF alpha) can regulate normal mammary epithelial cell (MEC) growth, morphogenesis, and, under certain circumstances, functional differentiation in a manner similar to epidermal growth factor (EGF). As TNF alpha has been shown to up-regulate EGF receptor (EGFR) expression and function in other systems, the present studies were undertaken to determine whether TNF alpha action in MEC was indirect through stimulation of the EGFR. An inhibitor of EGFR tyrosine kinase activity, PD158780, failed to block proliferation induced by 40 ng/ml TNF alpha and only partially inhibited growth in response to 2 ng/ml TNF alpha. PD158780 was also unable to suppress the extensive morphological development induced by either TNF alpha concentration. In contrast, the effects of TNF alpha and PD158780 on functional differentiation (i.e. casein accumulation) were time dependent. When measured on day 7 after 48 h of treatment, casein accumulation was unaffected by either concentration of TNF alpha or by PD158780. When assessed on day 21 after 16 days of treatment, however, casein levels were decreased by 40 ng/ml TNF alpha and increased by PD158780. Significantly, this PD158780-induced increase in casein was not observed in MEC that had been treated with both PD158780 and TNF alpha. These results thus suggest that EGFR tyrosine kinase activity is not necessary for TNF alpha action in normal MEC.

Tumor necrosis factor-alpha: a multifunctional regulator of mammary gland development

To determine whether tumor necrosis factor-alpha (TNF alpha) plays a physiological role in normal mammary gland development, TNF alpha and TNF receptor expression were measured in epithelial cells (MEC) isolated from mammary glands of virgin, pregnant, lactating, and postlactational (day 7 of involution) rats. TNF alpha messenger RNA (mRNA) increased significantly during pregnancy, then decreased during lactation and involution. The 26-kDa transmembrane form of TNF alpha protein, undetectable in MEC from virgin rats, increased throughout pregnancy and lactation, and disappeared during involution. In contrast, p55 TNF receptor (TNFR) mRNA levels peaked in early lactation and declined thereafter, whereas p75 TNFR mRNA levels rose steadily through lactation. Using agonistic antibodies specific to either TNFR, the individual roles of each TNFR were investigated in MEC in primary culture. The p55 TNFR was found to be the sole mediator of TNF alpha-induced proliferation. Intriguingly, the two receptors were found to have opposing effects on functional differentiation (casein accumulation), with inhibition occurring through the p55 receptor and stimulation through the p75 receptor. Taken together, these results suggest that TNF alpha plays a role in the growth and development of the mammary gland. In addition, both TNF receptors are important for TNF alpha function and may mediate different effects.