Erythrocyte membrane fluidity: A novel biomarker of residual cardiovascular risk in type 2 diabetes

AIMS

Improving the composition of circulating fatty acids (FA) leads to a reduction in cardiovascular diseases (CVD) in high-risk individuals. The membrane fluidity of red blood cells (RBC), which reflects circulating FA status, may be a valid biomarker of cardiovascular (CV) risk in type 2 diabetes (T2D).

METHODS

Red blood cell membrane fluidity, quantified as general polarization (GP), was assessed in 234 subjects with T2D, 86 with prior major CVD. Based on GP distribution, a cut-off of .445 was used to divide the study cohort into two groups: the first with higher GP, called GEL, and the second, defined as lower GP (LGP). Lipidomic analysis was performed to evaluate FA composition of RBC membranes.

RESULTS

Although with comparable CV risk factors, the LGP group had a greater percentage of patients with major CVD than the GEL group (40% vs 24%, respectively, p < .05). Moreover, in a logistic regression analysis, a lower GP value was independently associated with the presence of macrovascular complications. Lipidomic analysis showed a clear shift of LGP membranes towards a pro-inflammatory condition due to higher content of arachidonic acid and increased omega 6/omega 3 index.

CONCLUSIONS

Increased membrane fluidity is associated with a higher CV risk in subjects with T2D. If confirmed in prospective studies, membrane fluidity could be a new biomarker for residual CV risk assessment in T2D.

Effect of age and dietary habits on Red Blood Cell membrane fatty acids in a Southern Europe population (Basque Country)

The levels of blood eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are very variable and, in general, low in most of the world population. In this study, the effects of age, sex, COVID-19, and dietary habits on the lipid profile of the erythrocyte membranes were assessed in a sub-cohort of healthy population (N = 203) from a large cohort of individuals from the Basque Country, Spain, (AKRIBEA). Sex did not have an effect on RBC lipid profile. COVID-19 infected participants showed higher levels of DGLA. Oldest participants showed higher oleic acid, EPA and DHA levels. Arachidonic acid in RBC correlated positively with the intake of sunflower oil, butter, eggs, processed and red meat, whereas DHA and EPA correlated positively with oily and lean fish. Basque Country population showed lipid profiles similar to other high fish consuming countries, such as Italy and Japan. Baseline levels of the whole lipidomic profile of the RBC including SFA, MUFA and PUFA should be examined to obtain a better description of the health and nutritional status.

Competitive season effects on polyunsaturated fatty acid content in erythrocyte membranes of female football players

BACKGROUND

An optimal and correctly balanced metabolic status is essential to improve sports performance in athletes. Recent advances in omic tools, such as the lipid profile of the mature erythrocyte membranes (LPMEM), allow to have a comprehensive vision of the nutritional and metabolic status of these individuals to provide personalized recommendations for nutrients, specifically, the essential omega-3 and omega-6 fatty acids, individuating deficiencies/unbalances that can arise from both habitual diet and sportive activity. This work aimed to study the LPMEM in professional female football players during the football season for the first time and compare it with those defined as optimal values for the general population and a control group.

METHODS

An observational study was carried out on female football players from the Athletic Club (Bilbao) playing in the first division of the Spanish league. Blood samples were collected at three points: at the beginning, mid-season, and end of the season for three consecutive seasons (2019-2020, 2020-2021, and 2021-2022), providing a total of 160 samples from 40 women. The LPMEM analysis was obtained by GC-FID by published method and correlated to other individual data, such as blood biochemical parameters, body composition, and age.

RESULTS

We observed a significant increase in docosahexaenoic acid (DHA) (p 0.048) and total polyunsaturated fatty acid (PUFA) (p 0.021) in the first season. In the second season, we observed a buildup in the membrane arachidonic acid (AA) (p < .001) and PUFA (p < .001) contents when high training accumulated. In comparison with the benchmark of average population values, 69% of the football players showed lower levels of omega-6 dihomo-γ-linolenic acid (DGLA), whereas 88%, 44%, and 81% of the participants showed increased values of AA, eicosapentaenoic acid (EPA), and the ratio of saturated and monounsaturated fatty acids (SFA/MUFA), respectively. Regarding relationships between blood biochemical parameters, body composition, and age with LPMEM, we observed some mild negative correlations, such as AA and SFA/MUFA ratio with vitamin D levels (coefficient = -0.34 p = .0019 and coefficient = -.25 p = .042); DGLA with urea and cortisol (coefficient = -0.27 p < .006 and coefficient = .28 p < .0028) and AA with age (coefficient = -0.33 p < .001).

CONCLUSION

In conclusion, relevant variations in several fatty acids of the membrane fatty acid profile of elite female football players were observed during the competitive season and, in comparison with the general population, increased PUFA contents were confirmed, as reported in other sportive activities, together with the new aspect of DGLA diminution, an omega-6 involved in immune and anti-inflammatory responses. Our results highlight membrane lipidomics as a tool to ascertain the molecular profile of elite female football players with a potential application for future personalized nutritional strategies (diet and supplementation) to address unbalances created during the competitive season.

Fatty Acids Profile and the Relevance of Membranes as the Target of Nutrition-Based Strategies in Atopic Dermatitis: A Narrative Review

Recently, the prevalence of atopic dermatitis has increased drastically, especially in urban populations. This multifactorial skin disease is caused by complex interactions between various factors including genetics, environment, lifestyle, and diet. In eczema, apart from using an elimination diet, the adequate content of fatty acids from foods (saturated, monounsaturated, and polyunsaturated fatty acids) plays an important role as an immunomodulatory agent. Different aspects regarding atopic dermatitis include connections between lipid metabolism in atopic dermatitis, with the importance of the MUFA levels, as well as of the omega-6/omega-3 balance that affects the formation of long-chain (C20 eicosanoic and C22 docosaenoic) fatty acids and bioactive lipids from them (such as prostaglandins). Impair/repair of the functioning of epidermal barrier is influenced by these fatty acid levels. The purpose of this review is to drive attention to membrane fatty acid composition and its involvement as the target of fatty acid supplementation. The membrane-targeted strategy indicates the future direction for dermatological research regarding the use of nutritional synergies, in particular using red blood cell fatty acid profiles as a tool for checking the effects of supplementations to reach the target and influence the inflammatory/anti-inflammatory balance of lipid mediators. This knowledge gives the opportunity to develop personalized strategies to create a healthy balance by nutrition with an anti-inflammatory outcome in skin disorders.

Geometrical isomerization of arachidonic acid during lipid peroxidation interferes with ferroptosis

Geometrical mono-trans isomers of arachidonic acid (mtAA) are endogenous products of free radical-induced cis-trans double bond isomerization occurring to natural fatty acids during cell metabolism, including lipid peroxidation (LPO). Very little is known about the functional roles of mtAA and in general on the effects of mono-trans isomers of polyunsaturated fatty acids (mtPUFA) in various types of programmed cell death, including ferroptosis. Using HT1080 and MEF cell cultures, supplemented with 20 μM PUFA (i.e., AA, EPA or DHA) and their mtPUFA congeners, ferroptosis occurred in the presence of RSL3 (a direct inhibitor of glutathione peroxidase 4) only with the PUFA in their natural cis configuration, whereas mtPUFA showed an anti-ferroptotic effect. By performing the fatty acid-based membrane lipidome analyses, substantial differences emerged in the membrane fatty acid remodeling of the two different cell fates. In particular, during ferroptosis mtPUFA formation and their incorporation, together with the enrichment of SFA, occurred. This opens new perspectives in the role of the membrane composition for a ferroptotic outcome. While pre-treatment with AA promoted cell death for treatment with H₂O₂ and RSL3, mtAA did not. Cell death by AA supplementation was suppressed also in the presence of either ferroptosis inhibitors, such as the lipophilic antioxidant ferrostatin-1, or NADPH oxidase (NOX) inhibitors, including diphenyleneiodonium chloride and apocynin. Our results confirm a more complex scenario for ferroptosis than actually believed. While LPO processes are active, the importance of environmental lipid levels, balance among SFA, MUFA and PUFA in lipid pools and formation of mtPUFA influence the membrane phospholipid turnover, with crucial effects in the occurrence of cell death by ferroptosis.

Plasmalogens: Free Radical Reactivity and Identification of Trans Isomers Relevant to Biological Membranes

Plasmalogens are membrane phospholipids with two fatty acid hydrocarbon chains linked to L-glycerol, one containing a characteristic cis-vinyl ether function and the other one being a polyunsaturated fatty acid (PUFA) residue linked through an acyl function. All double bonds in these structures display the cis geometrical configuration due to desaturase enzymatic activity and they are known to be involved in the peroxidation process, whereas the reactivity through cis-trans double bond isomerization has not yet been identified. Using 1-(1Z-octadecenyl)-2-arachidonoyl-sn-glycero-3-phosphocholine (C18 plasm-20:4 PC) as a representative molecule, we showed that the cis-trans isomerization can occur at both plasmalogen unsaturated moieties, and the product has characteristic analytical signatures useful for omics applications. Using plasmalogen-containing liposomes and red blood cell (RBC) ghosts under biomimetic Fenton-like conditions, in the presence or absence of thiols, peroxidation, and isomerization processes were found to occur with different reaction outcomes due to the particular liposome compositions. These results allow gaining a full scenario of plasmalogen reactivity under free radical conditions. Moreover, clarification of the plasmalogen reactivity under acidic and alkaline conditions was carried out, identifying the best protocol for RBC membrane fatty acid analysis due to their plasmalogen content of 15-20%. These results are important for lipidomic applications and for achieving a full scenario of radical stress in living organisms.

Targeted and untargeted metabolomic approach for GDM diagnosis

Gestational diabetes mellitus (GDM) is a disorder which manifests itself for the first time during pregnancy and is mainly connected with glucose metabolism. It is also known that fatty acid profile changes in erythrocyte membranes and plasma could be associated with obesity and insulin resistance. These factors can lead to the development of diabetes. In the reported study, we applied the untargeted analysis of plasma in GDM against standard glucose-tolerant (NGT) women to identify the differences in metabolomic profiles between those groups. We found higher levels of 2-hydroxybutyric and 3-hydroxybutyric acids. Both secondary metabolites are associated with impaired glucose metabolism. However, they are products of different metabolic pathways. Additionally, we applied lipidomic profiling using gas chromatography to examine the fatty acid composition of cholesteryl esters in the plasma of GDM patients. Among the 14 measured fatty acids characterizing the representative plasma lipidomic cluster, myristic, oleic, arachidonic, and α-linoleic acids revealed statistically significant changes. Concentrations of both myristic acid, one of the saturated fatty acids (SFAs), and oleic acid, which belong to monounsaturated fatty acids (MUFAs), tend to decrease in GDM patients. In the case of polyunsaturated fatty acids (PUFAs), some of them tend to increase (e.g., arachidonic), and some of them tend to decrease (e.g., α-linolenic). Based on our results, we postulate the importance of hydroxybutyric acid derivatives, cholesteryl ester composition, and the oleic acid diminution in the pathophysiology of GDM. There are some evidence suggests that the oleic acid can have the protective role in diabetes onset. However, metabolic alterations that lead to the onset of GDM are complex; therefore, further studies are needed to confirm our observations.

Assessing the Formation of Purine Lesions in Mitochondrial DNA of Cockayne Syndrome Cells

Mitochondrial (mt) DNA and nuclear (n) DNA have known structures and roles in cells; however, they are rarely compared under specific conditions such as oxidative or degenerative environments that can create damage to the DNA base moieties. Six purine lesions were ascertained in the mtDNA of wild type (wt) CSA (CS3BE-wtCSA) and wtCSB (CS1AN-wtCSB) cells and defective counterparts CS3BE and CS1AN in comparison with the corresponding total (t) DNA (t = n + mt). In particular, the four 5',8-cyclopurine (cPu) and the two 8-oxo-purine (8-oxo-Pu) lesions were accurately quantified by LC-MS/MS analysis using isotopomeric internal standards after an enzymatic digestion procedure. The 8-oxo-Pu levels were found to be in the range of 25-50 lesions/107 nucleotides in both the mtDNA and tDNA. The four cPu were undetectable in the mtDNA both in defective cells and in the wt counterparts (CSA and CSB), contrary to their detection in tDNA, indicating a nonappearance of hydroxyl radical (HO•) reactivity within the mtDNA. In order to assess the HO• reactivity towards purine nucleobases in the two genetic materials, we performed γ-radiolysis experiments coupled with the 8-oxo-Pu and cPu quantifications on isolated mtDNA and tDNA from wtCSB cells. In the latter experiments, all six purine lesions were detected in both of the DNA, showing a higher resistance to HO• attack in the case of mtDNA compared with tDNA, likely due to their different DNA helical topology influencing the relative abundance of the lesions.

Effects of Aging and Disease Conditions in Brain of Tumor-Bearing Mice: Evaluation of Purine DNA Damages and Fatty Acid Pool Changes

The consequences of aging and disease conditions in tissues involve reactive oxygen species (ROS) and related molecular alterations of different cellular compartments. We compared a murine model of immunodeficient (SCID) xenografted young (4 weeks old) and old (17 weeks old) mice with corresponding controls without tumor implantation and carried out a compositional evaluation of brain tissue for changes in parallel DNA and lipids compartments. DNA damage was measured by four purine 5',8-cyclo-2'-deoxynucleosides, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG), and 8-oxo-7,8-dihydro-2'-deoxyadenosine (8-oxo-dA). In brain lipids, the twelve most representative fatty acid levels, which were mostly obtained from the transformation of glycerophospholipids, were followed up during the aging and disease progressions. The progressive DNA damage due to age and tumoral conditions was confirmed by raised levels of 5'S-cdG and 5'S-cdA. In the brain, the remodeling involved a diminution of palmitic acid accompanied by an increase in arachidonic acid, along both age and tumor progressions, causing increases in the unsaturation index, the peroxidation index, and total TFA as indicators of increased oxidative and free radical reactivity. Our results contribute to the ongoing debate on the central role of DNA and genome instability in the aging process, and on the need for a holistic vision, which implies choosing the best biomarkers for such monitoring. Furthermore, our data highlight brain tissue for its lipid remodeling response and inflammatory signaling, which seem to prevail over the effects of DNA damage.

Critical Review on Fatty Acid-Based Food and Nutraceuticals as Supporting Therapy in Cancer

Fatty acids have an important place in both biological and nutritional contexts and, from a clinical point of view, they have known consequences for diseases’ onset and development, including cancer. The use of fatty acid-based food and nutraceuticals to support cancer therapy is a multidisciplinary subject, involving molecular and clinical research. Knowledge regarding polyunsaturated fatty acids essentiality/oxidizability and the role of lipogenesis-desaturase pathways for cell growth, as well as oxidative reactivity in cancer cells, are discussed, since they can drive the choice of fatty acids using their multiple roles to support antitumoral drug activity. The central role of membrane fatty acid composition is highlighted for the application of membrane lipid therapy. As fatty acids are also known as biomarkers of cancer onset and progression, the personalization of the fatty acid-based therapy is also possible, taking into account other important factors such as formulation, bioavailability and the distribution of the supplementation. A holistic approach emerges combining nutra- and pharma-strategies in an appropriate manner, to develop further knowledge and applications in cancer therapy.

A convenient route to mono-trans polyunsaturated free fatty acids

Trans unsaturated fatty acids in humans may be originated both from dietary supplementation and from an endogenous free-radical-catalyzed cis−trans isomerization of fatty acid residues in naturally occurring cis lipids. The latter process affords geometrical isomers and the polyunsaturated fatty acid mono-trans isomers were demonstrated to be connected with stress conditions in living organisms. Synthesis of mono-trans polyunsaturated fatty acid is useful for analytical and biological research, and in this case, the availability of free fatty acids is needed as well as the possibility of mg scale of the synthetic protocol. Herein, we report a simple synthetic route to mono-trans isomers of arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid, which includes thiyl radical-catalyzed isomerization reaction of polyunsaturated fatty acid methyl esters and fraction isolation of mono-trans mixture isomers followed by optimization of hydrolysis condition to free fatty acids and purification of each mono-trans polyunsaturated fatty acid. Our approach to mono-trans polyunsaturated fatty acids as free acids can reach the mg scale, thus fostering more applications to biochemical and biological studies.

Effects of Oxygen Tension for Membrane Lipidome Remodeling of Cockayne Syndrome Cell Models

Oxygen is important for lipid metabolism, being involved in both enzymatic transformations and oxidative reactivity, and is particularly influent when genetic diseases impair the repair machinery of the cells, such as described for Cockayne syndrome (CS). We used two cellular models of transformed fibroblasts defective for CSA and CSB genes and their normal counterparts, grown for 24 h under various oxygen tensions (hyperoxic 21%, physioxic 5% and hypoxic 1%) to examine the fatty acid-based membrane remodeling by GC analysis of fatty acid methyl esters derived from membrane phospholipids. Overall, we first distinguished differences due to oxygen tensions: (a) hyperoxia induced a general boost of desaturase enzymatic activity in both normal and defective CSA and CSB cell lines, increasing monounsaturated fatty acids (MUFA), whereas polyunsaturated fatty acids (PUFA) did not undergo oxidative consumption; (b) hypoxia slowed down desaturase activities, mostly in CSA cell lines and defective CSB, causing saturated fatty acids (SFA) to increase, whereas PUFA levels diminished, suggesting their involvement in hypoxia-related signaling. CSB-deprived cells are the most sensitive to oxidation and CSA-deprived cells are the most sensitive to the radical-based formation of trans fatty acids (TFA). The results point to the need to finely differentiate biological targets connected to genetic impairments and, consequently, suggest the better definition of cell protection and treatments through accurate molecular profiling that includes membrane lipidomes.

Erythrocyte Membrane Nanomechanical Rigidity Is Decreased in Obese Patients

This work intends to describe the physical properties of red blood cell (RBC) membranes in obese adults. The hypothesis driving this research is that obesity, in addition to increasing the amount of body fat, will also modify the lipid composition of membranes in cells other than adipocytes. Forty-nine control volunteers (16 male, 33 female, BMI 21.8 ± 5.6 and 21.5 ± 4.2 kg/m², respectively) and 52 obese subjects (16 male and 36 female, BMI 38.2± 11.0 and 40.7 ± 8.7 kg/m², respectively) were examined. The two physical techniques applied were atomic force microscopy (AFM) in the force spectroscopy mode, which allows the micromechanical measurement of penetration forces, and fluorescence anisotropy of trimethylammonium diphenylhexatriene (TMA-DPH), which provides information on lipid order at the membrane polar–nonpolar interface. These techniques, in combination with lipidomic studies, revealed a decreased rigidity in the interfacial region of the RBC membranes of obese as compared to control patients, related to parallel changes in lipid composition. Lipidomic data show an increase in the cholesterol/phospholipid mole ratio and a decrease in sphingomyelin contents in obese membranes. ω-3 fatty acids (e.g., docosahexaenoic acid) appear to be less prevalent in obese patient RBCs, and this is the case for both the global fatty acid distribution and for the individual major lipids in the membrane phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS). Moreover, some ω-6 fatty acids (e.g., arachidonic acid) are increased in obese patient RBCs. The switch from ω-3 to ω-6 lipids in obese subjects could be a major factor explaining the higher interfacial fluidity in obese patient RBC membranes.

Sapienic Acid Metabolism Influences Membrane Plasticity and Protein Signaling in Breast Cancer Cell Lines

The importance of sapienic acid (6c-16:1), a monounsaturated fatty acid of the n-10 family formed from palmitic acid by delta-6 desaturase, and of its metabolism to 8c-18:1 and sebaleic acid (5c,8c-18:2) has been recently assessed in cancer. Data are lacking on the association between signaling cascades and exposure to sapienic acid comparing cell lines of the same cancer type. We used 50 μM sapienic acid supplementation, a non-toxic concentration, to cultivate MCF-7 and 2 triple-negative breast cancer cells (TNBC), MDA-MB-231 and BT-20. We followed up for three hours regarding membrane fatty acid remodeling by fatty acid-based membrane lipidome analysis and expression/phosphorylation of EGFR (epithelial growth factor receptor), mTOR (mammalian target of rapamycin) and AKT (protein kinase B) by Western blotting as an oncogenic signaling cascade. Results evidenced consistent differences among the three cell lines in the metabolism of n-10 fatty acids and signaling. Here, a new scenario is proposed for the role of sapienic acid: one based on changes in membrane composition and properties, and the other based on changes in expression/activation of growth factors and signaling cascades. This knowledge can indicate additional players and synergies in breast cancer cell metabolism, inspiring translational applications of tailored membrane lipid strategies to assist pharmacological interventions.

Effect of a Fiber D-Limonene-Enriched Food Supplement on Intestinal Microbiota and Metabolic Parameters of Mice on a High-Fat Diet

Several studies showed that D-Limonene can improve metabolic parameters of obese mice via various mechanisms, including intestinal microbiota modulation. Nevertheless, its effective doses often overcome the acceptable daily intake, rising concerns about toxicity. In this study we administered to C57BL/6 mice for 84 days a food supplement based on D-Limonene, adsorbed on dietary fibers (FLS), not able to reach the bloodstream, to counteract the metabolic effects of a high-fat diet (HFD). Results showed that daily administration of D-Limonene (30 and 60 mg/kg body weight) for 84 days decreased the weight gain of HFD mice. After 84 days we observed a statistically significant difference in weight gain in the group of mice receiving the higher dose of FLS compared to HFD mice (35.24 ± 4.56 g vs. 40.79 ± 3.28 g, p < 0.05). Moreover, FLS at both doses tested was capable of lowering triglyceridemia and also fasting glycemia at the higher dose. Some insights on the relevant fatty acid changes in hepatic tissues were obtained, highlighting the increased polyunsaturated fatty acid (PUFA) levels even at the lowest dose. FLS was also able to positively modulate the gut microbiota and prevent HFD-associated liver steatosis in a dose-dependent manner. These results demonstrate that FLS at these doses can be considered non-toxic and could be an effective tool to counteract diet-induced obesity and ameliorate metabolic profile in mice.

Omega 6 polyunsaturated fatty acids in red blood cell membrane are associated with xerostomia and taste loss in patients with breast cancer

Chemosensory and physical complaints are common disorders in cancer patients under chemotherapy treatments that may affect the food intake, leading to a decreased quality of life. Lipid metabolism is a major pathway of cancer proliferation, where erythrocyte membrane phospholipids and their fatty acid composition are promising tools for monitoring metabolic pathways. Relationship between lipid profile in erythrocyte membrane phospholipids and chemosensory alterations in 44 newly diagnosed patients with breast cancer was here investigated. Smell changes and xerostomia were the most common complaints, with xerostomia as the main influencing factor on the development of other taste disorders. Lipid profiles revealed significant negative correlation between diminution of linoleic acid levels and xerostomia as well as positive correlation between increased arachidonic acid and salty taste. The involvement of these polyunsaturated lipids suggests the importance of oxidative and nutritional conditions of cancer patients, which can affect the molecular status for taste signals.

The bacterial protective armor against stress: The cis-trans isomerase of unsaturated fatty acids, a cytochrome-c type enzyme

Bacteria have evolved several outstanding strategies to resist to compounds or factors that compromise their survival. The first line of defense of the cell against environmental stresses is the membrane with fatty acids as fundamental building blocks of phospholipids. In this review, we focus on a periplasmic heme enzyme that catalyzes the cis-trans isomerization of unsaturated fatty acids to trigger a decrease in the fluidity of the membrane in order to rapidly counteract the danger. We particularly detailed the occurrence of such cis-trans isomerase in Nature, the different stresses that are at the origin of the double bond isomerization, the first steps in the elucidation of the mechanism of this peculiar metalloenzyme and some aspects of its regulation.

On the relevance of hydroxyl radical to purine DNA damage

Hydroxyl radical (HO^•) is the most reactive toward DNA among the reactive oxygen species (ROS) generated in aerobic organisms by cellular metabolisms. HO^• is generated also by exogenous sources such as ionizing radiations. In this review we focus on the purine DNA damage by HO^• radicals. In particular, emphasis is given on mechanistic aspects for the various lesion formation and their interconnections. Although the majority of the purine DNA lesions like 8-oxo-purine (8-oxo-Pu) are generated by various ROS (including HO^•), the formation of 5',8-cyclopurine (cPu) lesions in vitro and in vivo relies exclusively on the HO^• attack. Methodologies generally utilized for the purine lesions quantification in biological samples are reported and critically discussed. Recent results on cPu and 8-oxo-Pu lesions quantification in various types of biological specimens associated with the cellular repair efficiency as well as with distinct pathologies are presented, providing some insights on their biological significance.

Autism Spectrum Disorder from the Womb to Adulthood: Suggestions for a Paradigm Shift

The wide spectrum of unique needs and strengths of Autism Spectrum Disorders (ASD) is a challenge for the worldwide healthcare system. With the plethora of information from research, a common thread is required to conceptualize an exhaustive pathogenetic paradigm. The epidemiological and clinical findings in ASD cannot be explained by the traditional linear genetic model, hence the need to move towards a more fluid conception, integrating genetics, environment, and epigenetics as a whole. The embryo-fetal period and the first two years of life (the so-called 'First 1000 Days') are the crucial time window for neurodevelopment. In particular, the interplay and the vicious loop between immune activation, gut dysbiosis, and mitochondrial impairment/oxidative stress significantly affects neurodevelopment during pregnancy and undermines the health of ASD people throughout life. Consequently, the most effective intervention in ASD is expected by primary prevention aimed at pregnancy and at early control of the main effector molecular pathways. We will reason here on a comprehensive and exhaustive pathogenetic paradigm in ASD, viewed not just as a theoretical issue, but as a tool to provide suggestions for effective preventive strategies and personalized, dynamic (from womb to adulthood), systemic, and interdisciplinary healthcare approach.

Molecular Differences Based on Erythrocyte Fatty Acid Profile to Personalize Dietary Strategies between Adults and Children with Obesity

As the obesity epidemic continues to grow inexorably worldwide, the need to develop effective strategies to prevent and control obesity seems crucial. The use of molecular tools can be useful to characterize different obesity phenotypes to provide more precise nutritional recommendations. This study aimed to determine the fatty acid (FA) profile of red blood cell (RBC) membranes, together with the evaluation of their dietary intake and biochemical parameters, of children and adults with obesity. An observational study was carried out on 196 children (113 with normal weight and 83 with obesity) and 91 adults (30 with normal weight and 61 with obesity). Mature RBC membrane phospholipids were analyzed for FA composition by gas chromatography-mass spectrometry (GC-MS). Dietary habits were evaluated using validated food frequency questionnaires (FFQ). Children with obesity presented higher levels of ω-6 polyunsaturated FAs (mainly linoleic acid, p = 0.01) and lower values of ω-3 FAs (mainly DHA, p < 0.001) compared with adults. Regarding blood biochemical parameters, children with obesity presented lower levels of glucose, LDL cholesterol, and alanine aminotransferase compared with adults with obesity. These lipidomic differences could be considered to provide specific nutritional recommendations for different age groups, based on an adequate fat intake.

Fatty Acid Remodeling of Membrane Glycerophospholipids Induced by Bleomycin and Iron Oxide Nanoparticles in Human Embryonic Kidney Cells

Bleomycin has a long-studied mechanism of action through the formation of a complex with metals, such as iron. The bleomycin-iron complex was recently shown to induce membrane damage by free radical reactivity. Because the use of Fe nanoparticles is spreading for drug delivery strategies, molecular mechanisms of cell damage must include different compartments in order to observe the progression of the cell reactivity. In this study, human embryonic kidney (HEK-293) cells were exposed for 24 h to bleomycin and polymeric iron oxide nanoparticles (Fe-NPs), alone or in combination. The fatty acid-based membrane lipidomic analysis evidenced the fatty acid remodeling in response to the treatments. Bleomycin alone caused the increase of saturated fatty acid (SFA) moieties in cell membrane glycerophospholipids with concomitant diminution of monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acid levels. Under Fe-NPs treatment, omega-6 PUFA decreased and trans fatty acid isomers increased. Under coadministration bleomycin and Fe-NPs, all membrane remodeling changes disappeared compared to those of the controls, with only an increase of omega-6 PUFA that elevates peroxidation index remaining. Our results highlight the important role of fatty-acid-based membrane lipidome monitoring to follow up the fatty acid reorganization induced by the drug, to be considered as a side effect of the pharmacological activity, suggesting the need of an integrated approach for the investigation of drug and carrier molecular mechanisms.

Fatty Acids and Membrane Lipidomics in Oncology: A Cross-Road of Nutritional, Signaling and Metabolic Pathways

Fatty acids are closely involved in lipid synthesis and metabolism in cancer. Their amount and composition are dependent on dietary supply and tumor microenviroment. Research in this subject highlighted the crucial event of membrane formation, which is regulated by the fatty acids' molecular properties. The growing understanding of the pathways that create the fatty acid pool needed for cell replication is the result of lipidomics studies, also envisaging novel fatty acid biosynthesis and fatty acid-mediated signaling. Fatty acid-driven mechanisms and biological effects in cancer onset, growth and metastasis have been elucidated, recognizing the importance of polyunsaturated molecules and the balance between omega-6 and omega-3 families. Saturated and monounsaturated fatty acids are biomarkers in several types of cancer, and their characterization in cell membranes and exosomes is under development for diagnostic purposes. Desaturase enzymatic activity with unprecedented de novo polyunsaturated fatty acid (PUFA) synthesis is considered the recent breakthrough in this scenario. Together with the link between obesity and cancer, fatty acids open interesting perspectives for biomarker discovery and nutritional strategies to control cancer, also in combination with therapies. All these subjects are described using an integrated approach taking into account biochemical, biological and analytical aspects, delineating innovations in cancer prevention, diagnostics and treatments.

The Erythrocyte Membrane Lipidome of Healthy Dogs: Creating a Benchmark of Fatty Acid Distribution and Interval Values

Molecular-based approaches are rapidly developing in medicine for the evaluation of physiological and pathological conditions and discovery of new biomarkers in prevention and therapy. Fatty acid diversity and roles in health and disease in humans are topical subjects of lipidomics. In particular, membrane fatty acid-based lipidomics provides molecular data of relevance in the study of human chronic diseases, connecting metabolic, and nutritional aspects to health conditions. In veterinary medicine, membrane lipidomics, and fatty acid profiles have not been developed yet in nutritional approaches to health and in disease conditions. Using a protocol widely tested in human profiling, in the present study erythrocyte membrane lipidome was examined in 68 clinically healthy dogs, with different ages, sex, and sizes. In particular, a cluster composed of 10 fatty acids, present in membrane glycerophospholipids and representative of structural and functional properties of cell membrane, was chosen, and quantitatively analyzed. The interval values and distribution for each fatty acid of the cluster were determined, providing the first panel describing the healthy dog lipidomic membrane profile, with interesting correlation to bodyweight increases. This molecular information can be advantageously developed as benchmark in veterinary medicine for the evaluation of metabolic and nutritional status in healthy and diseased dogs.

Free-Radical-Mediated Formation of Trans-Cardiolipin Isomers, Analytical Approaches for Lipidomics and Consequences of the Structural Organization of Membranes

Free-radical-mediated processes, such as peroxidation, isomerization and hydrogenation affecting fatty acid integrity and biological functions, have a trans-disciplinary relevance. Cardiolipins (CL, (1,3-diphosphatidyl-sn-glycerol)) and tetra-linoleoyl-CL are complex phospholipids, exclusively present in the Inner Mitochondrial Membrane (IMM) lipids, where they maintain membrane integrity and regulate enzyme functionalities. Peroxidation pathways and fatty acid remodeling are known causes of mitochondrial disfunctions and pathologies, including cancer. Free-radical-mediated isomerization with the change of the cis CL into geometrical trans isomers is an unknown process with possible consequences on the supramolecular membrane lipid organization. Here, the formation of mono-trans CL (MT-CL) and other trans CL isomers (T-CL) is reported using CL from bovine heart mitochondria and thiyl radicals generated by UV-photolysis from 2-mercaptoethanol. Analytical approaches for CL isomer separation and identification via ¹H/¹³C NMR are provided, together with the chemical study of CL derivatization to fatty acid methyl esters (FAME), useful for lipidomics and metabolomics research. Kinetics information of the radical chain isomerization process was obtained using γ-irradiation conditions. The CL isomerization affected the structural organization of membranes, as tested by the reduction in unilamellar liposome diameter, and accompanied the well-known process of oxidative consumption induced by Fenton reagents. These results highlight a potential new molecular modification pathway of mitochondrial lipids with wide applications to membrane functions and biological consequences.

Oxygen-Dependent Accumulation of Purine DNA Lesions in Cockayne Syndrome Cells

Cockayne Syndrome (CS) is an autosomal recessive neurodegenerative premature aging disorder associated with defects in nucleotide excision repair (NER). Cells from CS patients, with mutations in CSA or CSB genes, present elevated levels of reactive oxygen species (ROS) and are defective in the repair of a variety of oxidatively generated DNA lesions. In this study, six purine lesions were ascertained in wild type (wt) CSA, defective CSA, wtCSB and defective CSB-transformed fibroblasts under different oxygen tensions (hyperoxic 21%, physioxic 5% and hypoxic 1%). In particular, the four 5′,8-cyclopurine (cPu) and the two 8-oxo-purine (8-oxo-Pu) lesions were accurately quantified by LC-MS/MS analysis using isotopomeric internal standards after an enzymatic digestion procedure. cPu levels were found comparable to 8-oxo-Pu in all cases (3–6 lesions/10⁶ nucleotides), slightly increasing on going from hyperoxia to physioxia to hypoxia. Moreover, higher levels of four cPu were observed under hypoxia in both CSA and CSB-defective cells as compared to normal counterparts, along with a significant enhancement of 8-oxo-Pu. These findings revealed that exposure to different oxygen tensions induced oxidative DNA damage in CS cells, repairable by NER or base excision repair (BER) pathways. In NER-defective CS patients, these results support the hypothesis that the clinical neurological features might be connected to the accumulation of cPu. Moreover, the elimination of dysfunctional mitochondria in CS cells is associated with a reduction in the oxidative DNA damage.

The n-10 Fatty Acids Family in the Lipidome of Human Prostatic Adenocarcinoma Cell Membranes and Extracellular Vesicles

A new pathway leading to the n-10 fatty acid series has been recently evidenced, starting from sapienic acid, a monounsaturated fatty acid (MUFA) resulting from the transformation of palmitic acid by delta-6 desaturase. Sapienic acid has attracted attention as a novel marker of cancer cell plasticity. Here, we analyzed fatty acids, including the n-10 fatty acid contents, and for the first time, compared cell membranes and the corresponding extracellular vesicles (EV) of two human prostatic adenocarcinoma cell lines of different aggressiveness (PC3 and LNCaP). The n-10 components were 9-13% of the total fatty acids in both cancer cell lines and EVs, with total MUFA levels significantly higher in EVs of the most aggressive cell type (PC3). High sapienic/palmitoleic ratios indicated the preference for delta-6 versus delta-9 desaturase enzymatic activity in these cell lines. The expressions analysis of enzymes involved in desaturation and elongation by qRT-PCR showed a higher desaturase activity in PC3 and a higher elongase activity toward polyunsaturated fatty acids than toward saturated fatty acids, compared to LNCaP cells. Our results improve the present knowledge in cancer fatty acid metabolism and lipid phenotypes, highlighting EV lipidomics to monitor positional fatty acid isomer profiles and MUFA levels in cancer.

Effects of tocotrienol supplementation in Friedreich's ataxia: A model of oxidative stress pathology

Friedreich’s ataxia is an autosomal recessive disorder characterized by impaired mitochondrial function, resulting in oxidative stress. In this study, we aimed at evaluating whether tocotrienol, a phytonutrient that diffuses easily in tissues with saturated fatty layers, could complement the current treatment with idebenone, a quinone analogue with antioxidant properties. Five young Friedreich’s ataxia patients received a low-dose tocotrienol supplementation (5 mg/kg/day), while not discontinuing idebenone treatment. Several oxidative stress markers and biological parameters related to oxidative stress were evaluated at the time of initiation of treatment and 2 and 12 months post-treatment. Some oxidative stress-related parameters and some inflammation indices were altered in Friedreich’s ataxia patients taking idebenone alone and tended to be normal values following tocotrienol supplementation; likewise, a cardiac magnetic resonance study showed some improvement following one-year tocotrienol treatment. The pathway by which tocotrienol affects the Nrf2 modulation of hepcidin gene expression, a peptide involved in iron handling and in inflammatory responses, is viewed in the light of the disruption of the iron intracellular distribution and of the Nrf2 anergy characterizing Friedreich’s ataxia. This research provides a suitable model to analyze the efficacy of therapeutic strategies able to counteract the excess free radicals in Friedreich’s ataxia, and paves the way to long-term clinical studies.

How Does the Seed Pre-Germinative Metabolism Fight Against Imbibition Damage? Emerging Roles of Fatty Acid Cohort and Antioxidant Defence

During seed imbibition, lipids are engaged in membrane reorganization while facing free radical-mediated oxidative injury. In the present work, we explored changes in lipid components at different timepoints of imbibition (0.5, 2, 4, 6, and 8 h) in the legume Medicago truncatula, by combining biochemical approaches with targeted lipidomics and untargeted metabolomics. ROS and RNS (reactive oxygen and nitrogen species) accumulation was observed throughout the tested timepoints whereas lipid peroxidation increased at 4 h of imbibition. The seed response to oxidative damage was evidenced by a significant increase in tocopherols starting from 0.5 h of imbibition as well as by the reduction in total thiol content occurring at 2 h of imbibition. Since under physiological conditions, the proper functions of the cell membranes are strongly dependent on the qualitative and quantitative balance of fatty acid residues in phospholipids, the investigation was expanded to the fatty acid cohort of M. truncatula seeds. Total saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), omega(ω)-3 and omega(ω)-6 fatty acids showed fluctuations during seed imbibition. The most remarkable finding was the profile of the ω-3 PUFA docosopentaenoic acid (DPA, 7 cis, 10 cis, 13 cis, 16 cis, and 19 cis-22:5) that showed a peak (up to 1.0% of the total fatty acid content) at 0.5 and 8 h of imbibition, concomitant with the peaks observed in tocopherol levels. It is possible that the observed changes in DPA alter the physical properties of membranes, as reported in animal cells, triggering signaling pathways relevant for the cell defense against oxidative injury. Furthermore, the content and balance between tocopherols and PUFAs is regarded as a determinant of storage stability. No enhancement in trans-fatty acids occurred throughout imbibition, suggesting for a proper antioxidant response carried by the seed. Fatty acids profiles were integrated with data from untargeted metabolomics showing changes in lipid sub-pathways, among which fatty acid amide, lyso-phospholipids, and phospholipid metabolism. The emerging lipid profiles and dynamics are discussed in view of the overall imbibition damage generated during M. truncatula seed imbibition.

Lipidomic biomarkers and mechanisms of lipotoxicity in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) represents the most common form of chronic liver disease worldwide (about 25% of the general population) and 3-5% of patients develop non-alcoholic steatohepatitis (NASH), characterized by hepatocytes damage, inflammation and fibrosis, which increase the risk of developing liver failure, cirrhosis and hepatocellular carcinoma. The pathogenesis of NAFLD, particularly the mechanisms whereby a minority of patients develop a more severe phenotype, is still incompletely understood. In this review we examine the available literature on initial mechanisms of hepatocellular damage and inflammation, deriving from toxic effects of excess lipids. Accumulating data indicate that the total amount of triglycerides stored in the liver cells is not the main determinant of lipotoxicity and that specific lipid classes act as damaging agents. These lipotoxic species affect the cell behavior via multiple mechanisms, including activation of death receptors, endoplasmic reticulum stress, modification of mitochondrial function and oxidative stress. The gut microbiota, which provides signals through the intestine to the liver, is also reported to play a key role in lipotoxicity. Finally, we summarize the most recent lipidomic strategies utilized to explore the liver lipidome and its modifications in the course of NALFD. These include measures of lipid profiles in blood plasma and erythrocyte membranes that can surrogate to some extent lipid investigation in the liver.

New Insights into the Reaction Paths of Hydroxyl Radicals with Purine Moieties in DNA and Double-Stranded Oligodeoxynucleotides

The reaction of hydroxyl radical (HO^•) with DNA produces many primary reactive species and many lesions as final products. In this study, we have examined the optical spectra of intermediate species derived from the reaction of HO^• with a variety of single- and double-stranded oligodeoxynucleotides and ct-DNA in the range of 1 μs to 1 ms by pulse radiolysis using an Intensified Charged Coupled Device (ICCD) camera. Moreover, we applied our published analytical protocol based on an LC-MS/MS system with isotopomeric internal standards to enable accurate and precise measurements of purine lesion formation. In particular, the simultaneous measurement of the four purine 5′,8-cyclo-2′-deoxynucleosides (cPu) and two 8-oxo-7,8-dihydro-2′-deoxypurine (8-oxo-Pu) was obtained upon reaction of genetic material with HO^• radicals generated either by γ-radiolysis or Fenton-type reactions. Our results contributed to the debate in the literature regarding absolute level of lesions, method of HO^• radical generation, 5′R/5′S diastereomeric ratio in cPu, and relative abundance between cPu and 8-oxo-Pu.

Effects of somatostatin, curcumin, and quercetin on the fatty acid profile of breast cancer cell membranes

Breast cancer is a worldwide commonly found malignancy in women and effective treatment is regarded as a huge clinical challenge even in the presence of several treatment options. Extensive literature is available demonstrating polyphenols as phytopharmaceutical anticancer agents. Among the polyphenols, quercetin and curcumin have been reported to have a strong potential against breast cancer. However, so far, no comprehensive study has been performed to demonstrate the anticarcinogenic effects of curcumin, quercetin, and their combinations with somatostatin on the fatty acid profile of breast cancer cell membranes. We used MCF-7 and MDA-MB231 breast cancer cells incubated with curcumin and quercetin for 24 h, in the absence and presence of somatostatin, at their EC₅₀ concentrations to evaluate membrane fatty acid based functional lipidomics together with the followup of EGFR and MAPK signaling pathways. The two cell lines gave different membrane free fatty acid reorganization. In MCF-7 cells, the following changes were observed: an increase of ω6 linoleic acid in the cells incubated with somatostatin + quercetin and quercetin and a decrease of ω3 acids in the cells incubated with somatostatin + curcumin compared to somatostatin and significant increases of monounsaturated fatty acid (MUFA), mono-trans arachidonic acid levels and docosapentaenoic acid for the cells incubated with somatostatin + quercetin compared to the control cells. In MDA-MB231 cells, incubations with curcumin, quercetin, and somatostatin + quercetin induced the most significant membrane remodeling with the increase of stearic acid, diminution of ω6 linoleic, arachidonic acids, and ω3 (docosapentaenoic and docosahexaenoic acids). Distinct signaling pathway changes were found for these cell lines. In MCF-7 cells, separate or combined incubations with somatostatin and quercetin, significantly decreased EGFR and incubation with curcumin decreased MAPK signaling. In MDA-MB231 cells, incubation with curcumin decreased AKT1 and p-AKT1 (Thr308) levels. Incubation with curcumin and quercetin decreased the EGFR levels. Our results showed that cytostatic and antioxidant treatments can be combined to induce membrane fatty acid changes, including lipid isomerization as specific free radical driven process, and to influence signaling pathways. This study aimed to contribute to the literature on these antioxidants in the treatment of breast cancer to clarify the effects and mechanisms in combination with somatostatin.

Qualitative analysis of phospholipids and their oxidised derivatives - used techniques and examples of their applications related to lipidomic research and food analysis

Phospholipids (PLs) are important biomolecules that not only constitute structural building blocks and scaffolds of cell and organelle membranes but also play a vital role in cell biochemistry and physiology. Moreover, dietary exogenous PLs are characterised by high nutritional value and other beneficial health effects, which are confirmed by numerous epidemiological studies. For this reason, PLs are of high interest in lipidomics that targets both the analysis of membrane lipid distribution as well as correlates composition of lipids with their effects on functioning of cells, tissues and organs. Lipidomic assessments follow-up the changes occurring in living organisms, such as free radical attack and oxidative modifications of the polyunsaturated fatty acids (PUFAs) build in PL structures. Oxidised PLs (oxPLs) can be generated exogenously and supplied to organisms with processed food or formed endogenously as a result of oxidative stress. Cellular and tissue oxPLs can be a biomarker predictive of the development of numerous diseases such as atherosclerosis or neuroinflammation. Therefore, suitable high-throughput analytical techniques, which enable comprehensive analysis of PL molecules in terms of the structure of hydrophilic group, fatty acid (FA) composition and oxidative modifications of FAs, have been currently developed. This review addresses all aspects of PL analysis, including lipid isolation, chromatographic separation of PL classes and species, as well as their detection. The bioinformatic tools that enable handling of a large amount of data generated during lipidomic analysis are also discussed. In addition, imaging techniques such as confocal microscopy and mass spectrometry imaging for analysis of cellular lipid maps, including membrane PLs, are presented.

Hexadecenoic Fatty Acid Positional Isomers and De Novo PUFA Synthesis in Colon Cancer Cells

Palmitic acid metabolism involves delta-9 and delta-6 desaturase enzymes forming palmitoleic acid (9cis-16:1; n-7 series) and sapienic acid (6cis-16:1; n-10 series), respectively. The corresponding biological consequences and lipidomic research on these positional monounsaturated fatty acid (MUFA) isomers are under development. Furthermore, sapienic acid can bring to the de novo synthesis of the n-10 polyunsaturated fatty acid (PUFA) sebaleic acid (5cis,8cis-18:2), but such transformations in cancer cells are not known. The model of Caco-2 cell line was used to monitor sapienic acid supplementation (150 and 300 μM) and provide evidence of the formation of n-10 fatty acids as well as their incorporation at levels of membrane phospholipids and triglycerides. Comparison with palmitoleic and palmitic acids evidenced that lipid remodelling was influenced by the type of fatty acid and positional isomer, with an increase of 8cis-18:1, n-10 PUFA and a decrease of saturated fats in case of sapienic acid. Cholesteryl esters were formed only in cases with sapienic acid. Sapienic acid was the less toxic among the tested fatty acids, showing the highest EC₅₀s and inducing death only in 75% of cells at the highest concentration tested. Two-photon fluorescent microscopy with Laurdan as a fluorescent dye provided information on membrane fluidity, highlighting that sapienic acid increases the distribution of fluid regions, probably connected with the formation of 8cis-18:1 and the n-10 PUFA in cell lipidome. Our results bring evidence for MUFA positional isomers and de novo PUFA synthesis for developing lipidomic analysis and cancer research.

Effects of Somatostatin and Vitamin C on the Fatty Acid Profile of Breast Cancer Cell Membranes

Background:

Vitamin C (Vit C) is an important physiological antioxidant with growing applications in cancer. Somatostatin (SST) is a natural peptide with growth inhibitory effect in several mammary cancer models.

Objective:

The combined effects of SST and Vit C supplementation have never been studied in breast cancer cells so far.

Methods:

We used MCF-7 and MDA-MB231 breast cancer cells incubated with SST for 24h, in the absence and presence of Vit C, at their EC50 concentrations, to evaluate membrane fatty acid-profiles together with the follow-up of EGFR and MAPK signaling pathways.

Results:

The two cell lines gave different membrane reorganization: in MCF-7 cells, decrease of omega-6 linoleic acid and increase of omega-3 fatty acids (Fas) occurred after SST and SST+Vit C incubations, the latter also showing significant increases in MUFA, docosapentaenoic acid and mono-trans arachidonic acid levels. In MDA-MB231 cells, SST+Vit C incubation induced significant membrane remodeling with an increase of stearic acid and mono-trans-linoleic acid isomer, diminution of omega-6 linoleic, arachidonic acid and omega-3 (docosapentaenoic and docosadienoic acids). Distinct signaling pathways in these cell lines were studies: in MCF-7 cells, incubations with SST and Vit C, alone or in combination significantly decreased EGFR and MAPK signaling, whereas in MDA-MB231 cells, SST and Vit C incubations, alone or combined, decreased p-P44/42 MAPK levels, and increased EGFR levels.

Conclusion:

Our results showed that SST and Vit C can be combined to induce membrane fatty acid changes, including lipid isomerization through a specific free radical-driven process, influencing signaling pathways.

Altered Red Blood Cell Membrane Fatty Acid Profile in Cancer Patients

The fatty acid (FA) composition of red blood cell (RBC) membrane phospholipids of cancer patients can reflect tumor status, dietary intakes, and cancer type or therapy. However, the characteristic membrane profiles have so far not yet defined as a potential biomarker to monitor disease evolution. The present work provides the first evidence of cancer metabolic signatures affecting cell membranes that are independent of nutritional habits. From the Oncology Outpatient Unit of the Onkologikoa hospital, two groups of cancer patients (n = 54) and healthy controls (n = 37) were recruited, and mature RBCs membrane phospholipids were analyzed for FA profiling (GC-MS). Dietary habits were evaluated using a validated food frequency questionnaire. The adjusted Analysis of Covariance Test (ANCOVA) model revealed cancer patients to have a lower relative percentage of saturated fatty acids (SFA) (C16:0 (5.7%); C18:0 (15.9%)), and higher monounsaturated fatty acids (MUFA) (9c-C18:1 (12.9%) and 11c-C18:1 (54.5%)), compared to controls. In line with this, we observe that the desaturase enzymatic index (delta-9 desaturase (Δ9D), +28.3%) and the membrane saturation index (SI = SFA/MUFA; −27.3%) were similarly modulated. Polyunsaturated fatty acids (PUFA) families showed an increase of n-6 C18:2 and C20:3 (15.7% and 22.2% respectively), with no differences in n-6 C20:4 and n-3 PUFA (docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)). Importantly, these changes were found independent of foods and fat intakes from the diet. The membrane lipid profile in RBC was useful to ascertain the presence of two main metabolic signatures of increased desaturation activity and omega-6 in cancer patients, statistically independent from dietary habits.

[Cu(TPMA)(Phen)](ClO4)2: Metallodrug Nanocontainer Delivery and Membrane Lipidomics of a Neuroblastoma Cell Line Coupled with a Liposome Biomimetic Model Focusing on Fatty Acid Reactivity

The use of copper complexes for redox and oxidative-based mechanisms in therapeutic strategies is an important field of multidisciplinary research. Here, a novel Cu(II) complex [Cu(TPMA)(Phen)](ClO4)2 (Cu-TPMA-Phen, where TPMA = tris-(2-pyridylmethyl)amine and Phen = 1,10-phenanthroline) was studied using both the free and encapsulated forms. A hollow pH-sensitive drug-delivery system was synthesized, characterized, and used to encapsulate and release the copper complex, thus allowing for the comparison with the free drug. The human neuroblastoma-derived cell line NB100 was treated with 5 μM Cu-PMA-Phen for 24 h, pointing to the consequences on mono- and polyunsaturated fatty acids (MUFA and PUFA) present in the membrane lipidome, coupled with cell viability and death pathways (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium viability assay, flow cytometry, microscopy, caspase activation). In parallel, the Cu-TPMA-Phen reactivity with the fatty acid moieties of phospholipids was studied using the liposome model to work in a biomimetic environment. The main results concerned: (i) the membrane lipidome in treated cells, involving remodeling with a specific increase of saturated fatty acids (SFAs) and a decrease of MUFA, but not PUFA; (ii) cytotoxic events and lipidome changes did not occur for the encapsulated Cu-TPMA-Phen, showing the influence of such nanocarriers on drug activity; and (iii) the liposome behavior confirmed that MUFA and PUFA fatty acid moieties in membranes are not affected by oxidative and isomerization reactions, proving the different reactivities of thiyl radicals generated from amphiphilic and hydrophilic thiols and Cu-TPMA-Phen. This study gives preliminary but important elements of copper(II) complex reactivity in cellular and biomimetic models, pointing mainly to the effects on membrane reactivity and remodeling based on the balance between SFA and MUFA in cell membranes that are subjects of strong interest for chemotherapeutic activities as well as connected to nutritional strategies.

Lipid profile changes in erythrocyte membranes of women with diagnosed GDM

Gestational diabetes mellitus (GDM) is a glucose intolerance that begins or is first recognized during pregnancy. It is currently a growing health problem worldwide affecting from 1% to 14% of all pregnant women depending on racial and ethnic group as well as the diagnostic and screening criteria. Our preliminary study aimed at investigating the erythrocyte membrane fatty acid profiles of pregnant women, in particular with diagnosed with gestational diabetes mellitus (GDM), and with normal glucose tolerant (NGT) pregnant women as a control group. The study group comprised 43 pregnant women, 32 of whom were diagnosed with GDM according to the WHO criteria, and 11 with normal glucose tolerance. The erythrocyte membrane phospholipids were obtained according to the Folch extraction procedure. Fatty acids (FA) were analyzed by gas chromatography (GC) as the corresponding fatty acid methyl esters (FAME). A cluster of 14 fatty acids identified contained >98% of the recognized peaks in the GC analysis. The analysis of fatty acids from erythrocytes revealed important differences between GDM and NGT women in the third trimester, and the results were correlated with biochemical data. Among the 14 measured FA representing the membrane lipidomic profile, the levels of three saturated FA (myristic, palmitic, stearic acids) tended to decrease in GDM patients, with the percentage content of stearic acid significantly changed. The relative content of monounsaturated fatty acids (MUFA) tended to increase, in particular the oleic acid and vaccenic acid contents were significantly increased in erythrocyte membranes of the GDM group in comparison with the NGT group. The GDM group demonstrated higher sapienic acid levels (+29%) but this change was not statistically significant. This study revealed association between an impaired cis-vaccenic acid concentration in erythrocytes membrane and GDM development. No significant changes of polyunsaturated fatty acids (PUFA) were observed in GDM and NGT erythrocytes. We postulate, basing on the differences between the GDM and NGT lipidomic profiles, that stearic and cis-vaccenic acids can be considered as dual biomarkers of specific SFA-MUFA conversion pathway, involving the coupling of delta-9 desaturase and elongase enzymes. Our results indicate that the SFA-MUFA families may be involved in the pathophysiology of metabolic diseases such as GDM, but the further studies are needed to confirm our hypothesis. In conclusion, the erythrocyte membranes of GDM women undergo remodeling resulting in abnormal fatty acid profiles, which are reflection of the long-term status of organism and can have great impact on both the mother and her offspring.

Hippocampal lipidome and transcriptome profile alterations triggered by acute exposure of mice to GSM 1800 MHz mobile phone radiation: An exploratory study

BACKGROUND

The widespread use of wireless devices during the last decades is raising concerns about adverse health effects of the radiofrequency electromagnetic radiation (RF-EMR) emitted from these devices. Recent research is focusing on unraveling the underlying mechanisms of RF-EMR and potential cellular targets. The "omics" high-throughput approaches are powerful tools to investigate the global effects of RF-EMR on cellular physiology.

METHODS

In this work, C57BL/6 adult male mice were whole-body exposed (nExp  = 8) for 2 hr to GSM 1800 MHz mobile phone radiation at an average electric field intensity range of 4.3-17.5 V/m or sham-exposed (nSE  = 8), and the RF-EMR effects on the hippocampal lipidome and transcriptome profiles were assessed 6 hr later.

RESULTS

The data analysis of the phospholipid fatty acid residues revealed that the levels of four fatty acids [16:0, 16:1 (6c + 7c), 18:1 9c, eicosapentaenoic acid omega-3 (EPA, 20:5 ω3)] and the two fatty acid sums of saturated and monounsaturated fatty acids (SFA and MUFA) were significantly altered (p < 0.05) in the exposed group. The observed changes indicate a membrane remodeling response of the tissue phospholipids after nonionizing radiation exposure, reducing SFA and EPA, while increasing MUFA residues. The microarray data analysis demonstrated that the expression of 178 genes changed significantly (p < 0.05) between the two groups, revealing an impact on genes involved in critical biological processes, such as cell cycle, DNA replication and repair, cell death, cell signaling, nervous system development and function, immune system response, lipid metabolism, and carcinogenesis.

CONCLUSIONS

This study provides preliminary evidence that mobile phone radiation induces hippocampal lipidome and transcriptome changes that may explain the brain proteome changes and memory deficits previously shown by our group.

Aerobic Growth of Rhodococcus aetherivorans BCP1 Using Selected Naphthenic Acids as the Sole Carbon and Energy Sources

Naphthenic acids (NAs) are an important group of toxic organic compounds naturally occurring in hydrocarbon deposits. This work shows that Rhodococcus aetherivorans BCP1 cells not only utilize a mixture of eight different NAs (8XNAs) for growth but they are also capable of marked degradation of two model NAs, cyclohexanecarboxylic acid (CHCA) and cyclopentanecarboxylic acid (CPCA) when supplied at concentrations from 50 to 500 mgL-1. The growth curves of BCP1 on 8XNAs, CHCA, and CPCA showed an initial lag phase not present in growth on glucose, which presumably was related to the toxic effects of NAs on the cell membrane permeability. BCP1 cell adaptation responses that allowed survival on NAs included changes in cell morphology, production of intracellular bodies and changes in fatty acid composition. Transmission electron microscopy (TEM) analysis of BCP1 cells grown on CHCA or CPCA showed a slight reduction in the cell size, the production of EPS-like material and intracellular electron-transparent and electron-dense inclusion bodies. The electron-transparent inclusions increased in the amount and size in NA-grown BCP1 cells under nitrogen limiting conditions and contained storage lipids as suggested by cell staining with the lipophilic Nile Blue A dye. Lipidomic analyses revealed significant changes with increases of methyl-branched (MBFA) and polyunsaturated fatty acids (PUFA) examining the fatty acid composition of NAs-growing BCP1 cells. PUFA biosynthesis is not usual in bacteria and, together with MBFA, can influence structural and functional processes with resulting effects on cell vitality. Finally, through the use of RT (Reverse Transcription)-qPCR, a gene cluster (chcpca) was found to be transcriptionally induced during the growth on CHCA and CPCA. Based on the expression and bioinformatics results, the predicted products of the chcpca gene cluster are proposed to be involved in aerobic NA degradation in R. aetherivorans BCP1. This study provides first insights into the genetic and metabolic mechanisms allowing a Rhodococcus strain to aerobically degrade NAs.

Real time quantitative analysis of lipid storage and lipolysis pathways by confocal spectral imaging of intracellular micropolarity

Organisms store fatty acids in triacylglycerols in the form of lipid droplets, or hydrolyze triacylglycerols in response to energetic demands via activation of lipolytic or storage pathways. These pathways are complex sets of sequential reactions that are finely regulated in different cell types. Here we present a high spatial and temporal resolution-based method for the quantification of the turnover of fatty acids into triglycerides in live cells without introducing sample preparation artifacts. We performed confocal spectral imaging of intracellular micropolarity in cultured insulin secreting beta cells to detect micropolarity variations as they occur in time and at different pixels of microscope images. Acquired data are then analyzed in the framework of the spectral phasors technique. The method furnishes a metabolic parameter, which quantitatively assesses fatty acids - triacylglycerols turnover and the activation of lipolysis and storage pathways. Moreover, it provides a polarity profile, which represents the contribution of hyperpolar, polar and non-polar classes of lipids. These three different classes can be visualized on the image at a submicrometer resolution, revealing the spatial localization of lipids in cells under physiological and pathological settings. This new method allows for a fine-tuned, real-time visualization of the turnover of fatty acids into triglycerides in live cells with submicrometric resolution. It also detects imbalances between lipid storage and usage, which may lead to metabolic disorders within living cells and organisms.

Trans Lipid Library: Synthesis of Docosahexaenoic Acid (DHA) Monotrans Isomers and Regioisomer Identification in DHA-Containing Supplements

Docosahexaenoic acid (DHA) is a semiessential polyunsaturated fatty acid (PUFA) for eukaryotic cells that is found in natural sources such as fish and algal oils and widely used as an ingredient for omega-3 containing foods or supplements. DHA effects are connected to its natural structure with six cis double bonds, but geometrical monotrans isomers can be formed during distillation or deodorization processes, as an unwanted event that alters molecular characteristics and annihilates health benefits. The characterization of the six monotrans DHA regioisomers is an open issue to address for analytical, biological, and nutraceutical applications. Here we report the preparation, separation, and first identification of each isomer by a dual approach consisting of the following: (i) the direct thiyl radical-catalyzed isomerization of cis-DHA methyl ester and (ii) the two-step synthesis from cis-DHA methyl ester via monoepoxides as intermediates, which are separated and identified by nuclear magnetic resonance spectroscopy, followed by elimination for the unequivocal assignment of the double bond position. This monotrans DHA isomer library with NMR and GC analytical characterization was also used to examine the products of thiyl-radical-catalyzed isomerization of a fish oil sample and to evaluate the trans isomer content in omega-3 containing supplements commercially available in Italy and Spain.

trans-Double Bond-Containing Liposomes as Potential Carriers for Drug Delivery

The use of liposomes has been crucial for investigations in biomimetic chemical biology as a membrane model and in medicinal chemistry for drug delivery. Liposomes are made of phospholipids whose biophysical characteristics strongly depend on the type of fatty acid moiety, where natural unsaturated lipids always have the double bond geometry in the cis configuration. The influence of lipid double bond configuration had not been considered so far with respect to the competence of liposomes in delivery. We were interested in evaluating possible changes in the molecular properties induced by the conversion of the double bond from cis to trans geometry. Here we report on the effects of the addition of trans-phospholipids supplied in different amounts to other liposome constituents (cholesterol, neutral phospholipids and cationic surfactants), on the size, ζ-potential and stability of liposomal formulations and on their ability to encapsulate two dyes such as rhodamine B and fluorescein. From a biotechnological point of view, trans-containing liposomes proved to have different characteristics from those containing the cis analogues, and to influence the incorporation and release of the dyes. These results open new perspectives in the use of the unnatural lipid geometry, for the purpose of changing liposome behavior and/or of obtaining molecular interferences, also in view of synergic effects of cell toxicity, especially in antitumoral strategies.

An Integrated Approach to Explore Composition and Dynamics of Cholesterol-rich Membrane Microdomains in Sexual Stages of Malaria Parasite

Membrane microdomains that include lipid rafts, are involved in key physiological and pathological processes and participate in the entry of endocellular pathogens. These assemblies, enriched in cholesterol and sphingolipids, form highly dynamic, liquid-ordered phases that can be separated from the bulk membranes thanks to their resistance to solubilization by nonionic detergents. To characterize complexity and dynamics of detergent-resistant membranes of sexual stages of the rodent malaria parasite Plasmodium berghei, here we propose an integrated study of raft components based on proteomics, lipid analysis and bioinformatics. This analysis revealed unexpected heterogeneity and unexplored pathways associated with these specialized assemblies. Protein-protein relationships and protein-lipid co-occurrence were described through multi-component networks. The proposed approach can be widely applied to virtually every cell type in different contexts and perturbations, under physiological and/or pathological conditions.

Functional lipidomics in patients on home parenteral nutrition: Effect of lipid emulsions

AIM

To investigate the fatty acid-based functional lipidomics of patients on long-term home parenteral nutrition receiving different intravenous lipid emulsions.

METHODS

A cross-sectional comparative study was carried out on 3 groups of adults on home parenteral nutrition (HPN), receiving an HPN admixture containing an olive-soybean oil-based intravenous lipid emulsion (IVLE) (OO-IVLE; n = 15), a soybean- medium-chain triacylglycerol-olive-fish oil-based IVLE (SMOF-IVLE; n = 8) or HPN without IVLE (No-IVLE; n = 8) and 42 healthy controls (HCs). The inclusion criteria were: duration of HPN ≥ 3 mo, current HPN admixtures ≥ 2 mo and HPN infusions ≥ 2/wk. Blood samples were drawn 4-6 h after the discontinuation of the overnight HPN infusion. The functional lipidomics panel included: the red blood cell (RBC) fatty acid (FA) profile, molecular biomarkers [membrane fluidity: saturated/monounsaturated FA ratio = saturated fatty acid (SFA)/monounsaturated fatty acid (MUFA) index; inflammatory risk: n-6/n-3 polyunsaturated fatty acid (PUFA) ratio = n-6/n-3 index; cardiovascular risk: sum of n-3 eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) = n-3 index; free radical stress: sum of FA trans isomers = %trans index] and FA pathway enzyme activity estimate (delta-9-desaturase = D9D; delta-6-desaturase = D6D; delta-5-desaturase = D5D; elongase = ELO). Statistics were carried out using nonparametric tests. The amount of each FA was calculated as a percentage of the total FA content (relative%).

RESULTS

In the OO-IVLE group, the percentage of oleic acid in the RBCs was positively correlated with the weekly load of OO-IVLE (r = 0.540, P = 0.043). In the SMOF-IVLE cohort, the RBC membrane EPA and DHA were positively correlated with the daily amount of SMOF-IVLE (r = 0.751, P = 0.044) and the number of HPN infusions per week (r = 0.753; P = 0.046), respectively. The SMOF-IVLE group showed the highest EPA and DHA and the lowest arachidonic acid percentages (P < 0.001). The RBC membrane linoleic acid content was lower, and oleic and vaccenic acids were higher in all the HPN groups in comparison to the HCs. Vaccenic acid was positively correlated with the weekly HPN load of glucose in both the OO-IVLE (r = 0.716; P = 0.007) and the SMOF-IVLE (r = 0.732; P = 0.053) groups. The estimated activity of D9D was higher in all the HPN groups than in the HCs (P < 0.001). The estimated activity of D5D was lower in the SMOF-IVLE group than in the HCs (P = 0.013). The SFA/MUFA ratio was lower in all the HPN groups than in the HCs (P < 0.001). The n-6/n-3 index was lower and the n-3 index was higher in the SMOF-IVLE group in comparison to the HCs and to the other HPN groups (P < 0.001). The %trans index did not differ among the four groups.

CONCLUSION

The FA profile of IVLEs significantly influenced the cell membrane functional lipidomics. The amount of glucose in the HPN may play a relevant role, mediated by the insulin regulation of the FA pathway enzyme activities.

The Reaction of Thiyl Radical with Methyl Linoleate: Completing the Picture

Cis lipids can be converted by thiols and free radicals into trans lipids, which are therefore a valuable tell-tale for free radical activity in the cell's lipidome. Our previous studies have shown that polyunsaturated lipids are isomerized by alkanethiyl radicals (S^•) in a cycle propagated by reversible double-bond addition and terminated by radical H-abstraction from the lipid. A critical flaw in this picture has long been that the reported lipid abstraction rate from radiolysis studies is faster than addition-isomerization, implying that the "cycle" must be terminating faster than it is propagating! Herein, we resolved this longstanding puzzle by combining a detailed product analysis, with reinvestigation of the time-resolved kinetics, DFT calculations of the indicated pathways, and reformulation of the radical-stasis equations. We have determined thiol-coupled products in dilute solutions arise mainly from addition to the inside position of the bisallylic group, followed by rapid intramolecular H^• transfer, yielding allylic radicals (L_ZZ + S^• ⇄ SL^• → SL'^•) that are slowly reduced by thiol (SL'^• + SH → SL'H + S^•). The first-order grow-in rate of the L_-H^• signal (k_exp^280nm) may therefore be dominated by the addition-H-translocation rather than slower direct H^•-abstraction. Steady-state kinetic analysis of the new mechanism is consistent with products and the rates and trends for polyunsaturated fatty acids (PUFAs), monounsaturated fatty acids (MUFAs), and mixtures, with and without physiological [O₂]. Implications of this new paradigm for the thiol-ene reactivity fall in an interdisciplinary research area spanning from synthetic applications to metabolomics.

Wine lees modulate lipid metabolism and induce fatty acid remodelling in zebrafish

This study investigates the ability of a polyphenolic extract obtained from a wine lees by-product to modulate zebrafish lipid metabolism.