The effect of dietary lipid changes on the fatty acid composition and function of liver, heart and brain mitochondria in the rat at different ages

Sugar Intake: Are All Children Made of Sugar?

Introduction: A healthy diet is characterized by a variety of food and a balanced energy intake, which should accompany every human being since early childhood. Unfortunately, excessive consumption of protein, fat, and lately sugar are very common in developed countries. Sugar intakes are not easily quantifiable and comparable among subjects. Therefore, we decide to analyze dietary patterns in children of different ages and diets (with and without gluten) using a food and nutrient database and a new application called the “Zuccherometro”. Patients and methods: This is a descriptive observational study conducted among children that are recruited consecutively either during a pediatric evaluation or through a school survey. Sociodemographic, nutritional and anthropometric data, degree of physical activity, and presence of medical conditions are collected. Dietary intake data are obtained by a 24 h recall diet. Results: The study analyzes 400 children: 213 girls and 187 boys. The majority of children (70.7%) are in normal weight range with similar extreme values (6.5% obese and 6.7% underweight). Celiac disease is diagnosed in 186 children. Caloric intakes are in line with the recommendations in all age-distributed groups with the exception of adolescents (11–17 years old), whose caloric intake is lower than recommendations. Protein intakes, on the contrary, are always exceeding recommendations and are significantly elevated in preschool children, (more than three times the population reference intakes). As for sugar intakes, all the children except the 11–17 years adolescents exceed the recommended cut off of 15% of daily calories. The same trend is obtained using the “Zuccherometro” that shows different percentages of age-stratified children exceeding the reference values: 1–3 years, 59% of children; 4–6 years, 68%; 7–10 years, 39.8%; 11–14 years, 25.5%; 15–17 years, 24.5%. The sugar load consists of both natural or added sugars (fructose and lactose) in food or beverages. Sugar intakes are more generously consumed by all age-stratified controls than by celiac children with the exception of the youngest ones (1–3 years old) and male adolescents. Conclusion: Since high sugar intakes are constantly accompanying children during their growth, important dietary education and coordination between families and institutions are mandatory.

Stearic Acid Supplementation in High Protein to Carbohydrate (P:C) Ratio Diet Improves Physiological and Mitochondrial Functions of Drosophila melanogaster parkin Null Mutants

Optimizing dietary macronutrients benefits the prevention and management of many human diseases but there is conflicting dietary advice for Parkinson's disease (PD), and no single strategy is universally recommended. Recently, it was shown that dietary stearic acid (C18:0) improves survival and mitochondrial functions in the parkin null Drosophila model of PD. Here, we incorporate stearic acid into high protein and high carbohydrate diets and study survival, climbing ability, mitochondrial membrane potential, respiration, basal reactive oxygen species, and conduct lipidomics assays. We observed that parkin null flies showed improvement in all assays tested when stearic acid was added to the high protein diet but not to the high carbohydrate diet. When lipid proportion was examined, we observed higher levels in flies fed the high protein diet with stearic acid diet and the high carbohydrate diet. Unexpectedly, free levels of fatty acids exhibited opposite trend. Combined, these data suggest that dietary Protein: Carbohydrate ratio and stearic acid influences levels of bound fatty acids. The mechanisms that influence free and bound fatty-acid levels remain to be explored, but one possible explanation is that breakdown products can bind to membranes and improve the mitochondrial functions of parkin null flies.

Investigating the Role of Mitochondria in Type 2 Diabetes - Lessons from Lipidomics and Proteomics Studies of Skeletal Muscle and Liver

Mitochondrial dysfunction is discussed as a key player in the pathogenesis of type 2 diabetes mellitus (T2Dm), a highly prevalent disease rapidly developing as one of the greatest global health challenges of this century. Data however about the involvement of mitochondria, central hubs in bioenergetic processes, in the disease development are still controversial. Lipid and protein homeostasis are under intense discussion to be crucial for proper mitochondrial function. Consequently proteomics and lipidomics analyses might help to understand how molecular changes in mitochondria translate to alterations in energy transduction as observed in the healthy and metabolic diseases such as T2Dm and other related disorders. Mitochondrial lipids integrated in a tool covering proteomic and functional analyses were up to now rarely investigated, although mitochondrial lipids might provide a possible lynchpin in the understanding of type 2 diabetes development and thereby prevention. In this chapter state-of-the-art analytical strategies, pre-analytical aspects, potential pitfalls as well as current proteomics and lipidomics-based knowledge about the pathophysiological role of mitochondria in the pathogenesis of type 2 diabetes will be discussed.

Relevance of functional foods in the Mediterranean diet: the role of olive oil, berries and honey in the prevention of cancer and cardiovascular diseases

The traditional Mediterranean diet (MedDiet) is a well-known dietary pattern associated with longevity and improvement of life quality as it reduces the risk of the most common chronic pathologies, such as cancer and cardiovascular diseases (CVDs), that represent the principal cause of death worldwide. One of the most characteristic foods of MedDiet is olive oil, a very complex matrix, which constitutes the main source of fats and is used in the preparation of foods, both raw as an ingredient in recipes, and in cooking. Similarly, strawberries and raspberries are tasty and powerful foods which are commonly consumed in the Mediterranean area in fresh and processed forms and have attracted the scientific and consumer attention worldwide for their beneficial properties for human health. Besides olive oil and berries, honey has lately been introduced in the MedDiet thanks to its relevant nutritional, phytochemical and antioxidant profile. It is a sweet substance that has recently been classified as a functional food. The aim of this review is to present and discuss the recent evidence, obtained from in vitro, in vivo and epidemiological studies, on the potential roles exerted by these foods in the prevention and progression of different types of cancer and CVDs.

Modulation of age related protein expression changes by gelam honey in cardiac mitochondrial rats

Aging is characterized by progressive decline in biochemical and physiological functions. According to the free radical theory of aging, aging results from oxidative damage due to the accumulation of excess reactive oxygen species (ROS). Mitochondria are the main source of ROS production and are also the main target for ROS. Therefore, a diet high in antioxidant such as honey is potentially able to protect the body from ROS and oxidative damage. Gelam honey is higher in flavonoid content and phenolic compounds compared to other local honey. This study was conducted to determine the effects of gelam honey on age related protein expression changes in cardiac mitochondrial rat. A total of 24 Sprague-Dawley male rats were divided into two groups: the young group (2 months old), and aged group (19 months old). Each group were then subdivided into two groups: control group (force-fed with distilled water), and treatment group (force-fed with gelam honey, 2.5 g/kg), and were treated for 8 months. Comparative proteomic analysis of mitochondria from cardiac tissue was then performed by high performance mass spectrometry (Q-TOF LCMS/MS) followed by validation of selected proteins by Western blotting. Proteins were identified using Spectrum Mill software and were subjected to stringent statistical analysis. A total of 286 proteins were identified in the young control group (YC) and 241 proteins were identified in the young gelam group (YG). In the aged group, a total of 243 proteins were identified in control group (OC), and 271 proteins in gelam group (OG). Comparative proteome profiling identified 69 proteins with different abundance (p < 0.05) in OC when compared to YC, and also in YG when compared to YC. On the other hand, 55 proteins were found to be different in abundance when comparing OG with OC. In the aged group, gelam honey supplementation affected the relative abundance of 52 proteins with most of these proteins showing a decrease in the control group. Bioinformatics analysis showed that the majority of the affected proteins were involved in the respiratory chain (OXPHOS) which play an important role in maintaining mitochondrial function.

Lipid-Mediated Modulation of Intracellular Ion Channels and Redox State: Physiopathological Implications

Significance: Ion channels play an important role in the regulation of organelle function within the cell, as proven by increasing evidence pointing to a link between altered function of intracellular ion channels and different pathologies ranging from cancer to neurodegenerative diseases, ischemic damage, and lysosomal storage diseases. Recent Advances: A link between these pathologies and redox state as well as lipid homeostasis and ion channel function is in the focus of current research. Critical Issues: Ion channels are target of modulation by lipids and lipid messengers, although in most cases the mechanistic details have not been clarified yet. Ion channel function importantly impacts production of reactive oxygen species (ROS), especially in the case of mitochondria and lysosomes. ROS, in turn, may modulate the function of intracellular channels triggering thereby a feedback control under physiological conditions. If produced in excess, ROS can be harmful to lipids and may produce oxidized forms of these membrane constituents that ultimately affect ion channel function by triggering a "circulus vitiosus." Future Directions: The present review summarizes our current knowledge about the contribution of intracellular channels to oxidative stress and gives examples of how these channels are modulated by lipids and how this modulation may affect ROS production in ROS-related diseases. Future studies need to address the importance of the regulation of intracellular ion channels and related oxidative stress by lipids in various physiological and pathological contexts. Antioxid. Redox Signal. 28, 949-972.

Purity matters: A workflow for the valid high-resolution lipid profiling of mitochondria from cell culture samples

Subcellular lipidomics is a novel field of research that requires the careful combination of several pre-analytical and analytical steps. To define a reliable strategy for mitochondrial lipid profiling, we performed a systematic comparison of different mitochondria isolation procedures by western blot analyses and comprehensive high-resolution lipidomics. Using liver-derived HepG2 cells, we compared three common mitochondria isolation methods, differential centrifugation (DC), ultracentrifugation (UC) and a magnetic bead-assisted method (MACS). In total, 397 lipid species, including 32 cardiolipins, could be quantified in only 100 μg (by protein) of purified mitochondria. Mitochondria isolated by UC showed the highest enrichment in the mitochondria-specific cardiolipins as well as their precursors, phosphatidylglycerols. Mitochondrial fractions obtained by the commonly used DC and the more recent MACS method contained substantial contaminations by other organelles. Employing these isolation methods when performing lipidomics analyses from cell culture mitochondria may lead to inaccurate results. To conclude, we present a protocol how to obtain reliable mitochondria-specific lipid profiles from cell culture samples and show that quality controls are indispensable when performing mitochondria lipidomics.

Dietary Fatty Acids and Temperature Modulate Mitochondrial Function and Longevity in Drosophila

Fluctuations in temperature and resource availability are conditions many organisms contend with in nature. Specific dietary nutrients such as fatty acids play an essential role in reproduction, cold adaptation, and metabolism in a variety of organisms. The present study characterizes how temperature and diet interact to modulate Drosophila physiology and life span. Flies were raised on media containing specific saturated, monounsaturated, or polyunsaturated fatty acids supplements at low concentrations and were placed in varied thermal environments. We found that dietary long-chain polyunsaturated fatty acids improve chill coma recovery and modulate mitochondrial function. Additionally, monounsaturated and polyunsaturated fatty acid food supplements were detrimental to life span regardless of temperature, and antioxidants were able to partially rescue this effect. This study provides insight into environmental modulation of Drosophila physiology and life span.

Effects of dietary fatty acids on mitochondrial phospholipid compositions, oxidative status and mitochondrial gene expression of zebrafish at different ages

Mitochondrial decay is generally associated with impairment in the organelle bioenergetics function and increased oxidative stress, and it appears that deterioration of mitochondrial inner membrane phospholipids (PL) and accumulation of mitochondrial DNA (mtDNA) mutations are among the main mechanisms involved in this process. In the present study, mitochondrial membrane PL compositions, oxidative status (TBARS content and SOD activity) and mtDNA gene expression of muscle and liver were analyzed in zebrafish fed two diets with lipid supplied either by rapeseed oil (RO) or a blend 60:40 of RO and DHA500 TG oil (DHA). Two feeding trials were performed using zebrafish from the same population of two ages (8 and 21 months). Dietary FA composition affected fish growth in 8-month-old animals, which could be related to an increase in stress promoted by diet composition. Lipid peroxidation was considerably higher in mitochondria of 8-month-old zebrafish fed the DHA diet than in animals fed the RO diet. This could indicate higher oxidative damage to mitochondrial lipids, very likely due to increased incorporation of DHA in PL of mitochondrial membranes. Lipids would be among the first molecules affected by mitochondrial reactive oxygen species, and lipid peroxidation could propagate oxidative reactions that would damage other molecules, including mtDNA. Mitochondrial lipid peroxidation and gene expression of 21-month-old fish showed lower responsiveness to diet composition than those of younger fish. Differences found in the effect of diet composition on mitochondrial lipids between the two age groups could be indicating age-related changes in the ability to maintain structural homeostasis of mitochondrial membranes.

Beneficial Effects of Ethanolic and Hexanic Rice Bran Extract on Mitochondrial Function in PC12 Cells and the Search for Bioactive Components

Mitochondria are involved in the aging processes that ultimately lead to neurodegeneration and the development of Alzheimer’s disease (AD). A healthy lifestyle, including a diet rich in antioxidants and polyphenols, represents one strategy to protect the brain and to prevent neurodegeneration. We recently reported that a stabilized hexanic rice bran extract (RBE) rich in vitamin E and polyphenols (but unsuitable for human consumption) has beneficial effects on mitochondrial function in vitro and in vivo (doi:10.1016/j.phrs.2013.06.008, 10.3233/JAD-132084). To enable the use of RBE as food additive, a stabilized ethanolic extract has been produced. Here, we compare the vitamin E profiles of both extracts and their effects on mitochondrial function (ATP concentrations, mitochondrial membrane potential, mitochondrial respiration and mitochondrial biogenesis) in PC12 cells. We found that vitamin E contents and the effects of both RBE on mitochondrial function were similar. Furthermore, we aimed to identify components responsible for the mitochondria-protective effects of RBE, but could not achieve a conclusive result. α-Tocotrienol and possibly also γ-tocotrienol, α-tocopherol and δ-tocopherol might be involved, but hitherto unknown components of RBE or a synergistic effect of various components might also play a role in mediating RBE’s beneficial effects on mitochondrial function.

The mitochondrial-targeted antioxidant, MitoQ, increases liver mitochondrial cardiolipin content in obesogenic diet-fed rats

Cardiolipin (CL), a unique mitochondrial phospholipid, plays a key role in several processes of mitochondrial bioenergetics as well as in mitochondrial membrane stability and dynamics. The present study was designed to determine the effect of MitoQ, a mitochondrial-targeted antioxidant, on the content of liver mitochondrial membrane phospholipids, in particular CL, and its fatty acid composition in obesogenic diet-fed rats. To do this, twenty-four 6week old male Sprague Dawley rats were randomized into three groups of 8 animals and fed for 8weeks with either a control diet, a high fat diet (HF), or a HF diet with MitoQ (HF+MitoQ). Phospholipid classes and fatty acid composition were assayed by chromatographic methods in liver and liver mitochondria. Mitochondrial bioenergetic function was also evaluated. While MitoQ had no or slight effects on total liver fatty acid composition and phospholipid classes and their fatty acid composition, it had major effects on liver mitochondrial phospholipids and mitochondrial function. Indeed, MitoQ both increased CL synthase gene expression and CL content of liver mitochondria and increased 18:2n-6 (linoleic acid) content of mitochondrial phospholipids by comparison to the HF diet. Moreover, mitochondrial CL content was positively correlated to mitochondrial membrane fluidity, membrane potential and respiration, as well as to ATP synthase activity, while it was negatively correlated to mitochondrial ROS production. These findings suggest that MitoQ may decrease pathogenic alterations to CL content and profiles, thereby preserving mitochondrial function and attenuating the development of some of the features of metabolic syndrome in obesogenic diet-fed rats.

The influence of dietary fat source on liver and skeletal muscle mitochondrial modifications and lifespan changes in calorie-restricted mice

The Membrane Theory of Aging proposes that lifespan is inversely related to the level of unsaturation in membrane phospholipids. Calorie restriction (CR) without malnutrition extends lifespan in many model organisms, which may be related to alterations in membrane phospholipids fatty acids. During the last few years our research focused on studying how altering the predominant fat source affects the outcome of CR in mice. We have established four dietary groups: one control group fed 95 % of a pre-determined ad libitum intake (in order to prevent obesity), and three CR groups fed 40 % less than ad libitum intake. Lipid source for the control and one of the CR groups was soybean oil (high in n-6 PUFA) whereas the two remaining CR groups were fed diets containing fish oil (high in n-3 PUFA), or lard (high in saturated and monounsaturated fatty acids). Dietary intervention periods ranged from 1 to 18 months. We performed a longitudinal lifespan study and a cross-sectional study set up to evaluate several mitochondrial parameters which included fatty acid composition, H(+) leak, activities of electron transport chain enzymes, ROS generation, lipid peroxidation, mitochondrial ultrastructure, and mitochondrial apoptotic signaling in liver and skeletal muscle. These approaches applied to different cohorts of mice have independently indicated that lard as a fat source often maximizes the effects of 40 % CR on mice. These effects could be due to significant increases of monounsaturated fatty acids levels, in accordance with the Membrane Theory of Aging.

Dietary fatty acids affect mitochondrial phospholipid compositions and mitochondrial gene expression of rainbow trout liver at different ages

Mitochondria are among the first responders to various stressors that challenge the homeostasis of cells and organisms. Mitochondrial decay is generally associated with impairment in the organelle bioenergetics function and increased oxidative stress, and it appears that deterioration of mitochondrial inner membrane phospholipids (PL), particularly cardiolipin (CL), and accumulation of mitochondrial DNA (mtDNA) mutations are among the main mechanisms involved in this process. In the present study, liver mitochondrial membrane PL compositions, lipid peroxidation, and mtDNA gene expression were analyzed in rainbow trout fed three diets with the same base formulation but with lipid supplied either by fish oil (FO), rapeseed oil (RO), or high DHA oil (DHA) during 6 weeks. Specifically, two feeding trials were performed using fish from the same population of two ages (1 and 3 years), and PL class compositions of liver mitochondria, fatty acid composition of individual PL classes, TBARS content, and mtDNA expression were determined. Dietary fatty acid composition strongly affected mitochondrial membrane composition from trout liver but observed changes did not fully reflect the diet, particularly when it contained high DHA. The changes were PL specific, CL being particularly resistant to changes in DHA. Some significant differences observed in expression of mtDNA with diet may suggest long-term dietary effects in mitochondrial gene expression which could affect electron transport chain function. All the changes were influenced by fish age, which could be related to the different growth rates observed between 1- and 3-year-old trout but that could also indicate age-related changes in the ability to maintain structural homeostasis of mitochondrial membranes.

The effects of bioactive compounds from plant foods on mitochondrial function: a focus on apoptotic mechanisms

Mitochondria are essential organelles for cellular integrity and functionality maintenance and their imparement is implicated in the development of a wide range of diseases, including metabolic, cardiovascular, degenerative and hyperproliferative pathologies. The identification of different compounds able to interact with mitochondria for therapeutic purposes is currently becoming of primary importance. Indeed, it is well known that foods, particularly those of vegetable origin, present several constituents with beneficial effects on health. This review summarizes and updates the most recent findings concerning the mechanisms through which different dietary compounds from plant foods affect mitochondria functionality in healthy and pathological in vitro and in vivo models, paying particular attention to the pathways involved in mitochondrial biogenesis and apoptosis.

Mitochondrial membrane lipid remodeling in pathophysiology: a new target for diet and therapeutic interventions

Mitochondria are arbiters in the fragile balance between cell life and death. These organelles present an intricate membrane system, with a peculiar lipid composition and displaying transverse as well as lateral asymmetry. Some lipids are synthesized inside mitochondria, while others have to be imported or acquired in the form of precursors. Here, we review different processes, including external interventions (e.g., diet) and a range of biological events (apoptosis, disease and aging), which may result in alterations of mitochondrial membrane lipid content. Cardiolipin, the mitochondria lipid trademark, whose biosynthetic pathway is highly regulated, will deserve special attention in this review. The modulation of mitochondrial membrane lipid composition, especially by diet, as a therapeutic strategy for the treatment of some pathologies will be also addressed.

Rapeseed oil-rich diet alters hepatic mitochondrial membrane lipid composition and disrupts bioenergetics

Diet is directly related with physiological alterations occurring at a cell and subcellular level. However, the role of diet manipulation on mitochondrial physiology is still largely unexplored. Aiming at correlating diet with alterations of mitochondrial membrane composition and bioenergetics, Wistar-Han male rats were fed for 11, 22 and 33 days with a rapeseed oil-based diet and mitochondrial bioenergetics, and membrane composition were compared at each time point with a standard diet group. Considerable differences were noticed in mitochondrial membrane lipid composition, namely in terms of fatty acyl chains and relative proportions of phospholipid classes, the modified diet inducing a decrease in the saturated to unsaturated molar ratio and an increase in the phosphatidylcholine to phosphatidylethanolamine molar ratio. Mass spectrometry lipid analysis showed significant differences in the major species of cardiolipin, with an apparent increased incorporation of oleic acid as a result of exposure to the modified diet. Rats fed the modified diet during 22 days showed decreased hepatic mitochondrial state 3 respiration and were more susceptible to Ca(2+)-induced transition pore opening. Rapeseed oil-enriched diet also appeared to promote a decrease in hydroperoxide production by the respiratory chain, although a simultaneous decrease in vitamin E content was detected. In conclusion, our data indicate that the rapeseed oil diet causes negative alterations on hepatic mitochondrial bioenergetics, which may result from membrane remodeling. Such alterations may have an impact not only on energy supply to the cell, but also on drug-induced hepatic mitochondrial liabilities.

Qualitative Characterization of the Rat Liver Mitochondrial Lipidome using LC-MS Profiling and High Energy Collisional Dissociation (HCD) All Ion Fragmentation

Lipids play multiple roles essential for proper mitochondrial function, from their involvement in membrane structure and fluidity, cellular energy storage, and signaling. Lipids are also major targets for reactive species, and their peroxidation byproducts themselves mediate further damage. Thousands of lipid species, from multiple classes and categories, are involved in these processes, suggesting lipid quantitative and structural analysis can help provide a better understanding of mitochondrial physiological status. Due to the diversity of lipids that contribute to and reflect mitochondrial function, analytical methods should ideally cover a wide range of lipid classes, and yield both quantitative and structural information. We developed a high resolution LC-MS method that is able to monitor the major lipid classes found in biospecimens (ie. biofluids, cells and tissues) with relative quantitation in an efficient, sensitive, and robust manner while also characterizing individual lipid side-chains, by all ion HCD fragmentation and chromatographic alignment. This method was used to profile the liver mitochondrial lipids from 192 rats undergoing a dietary macronutrient study in which changes in mitochondria function are related to changes in the major fat and glycemic index component of each diet. A total of 381 unique lipids, spanning 5 of the major LIPID MAPS defined categories, including fatty acyls, glycerophospholipids, glycerolipids, sphingolipids and prenols, were identified in mitochondria using the non-targeted LC-MS analysis in both positive and negative mode. The intention of this report is to show the breadth of this non-targeted LC-MS profiling method with regards to its ability to profile, identify and characterize the mitochondrial lipidome and the details of this will be discussed.

Differential effects of linoleic and alpha-linolenic fatty acids on spatial and temporal mitochondrial distribution and activity in bovine oocytes

Using specific stains and confocal microscope imaging, the patterns of mitochondrial distribution, mitochondrial inner membrane potential and reactive oxygen species (ROS) levels during bovine oocyte maturation were determined in the presence or absence of physiological concentrations of linoleic acid (LA; 100µM) or α-linolenic acid (ALA; 50µM). Mitochondrial distribution in control oocytes at 0h was mainly peripheral and changed to a diffused pattern after 1h of culture; this was maintained up to 24h. Mitochondrial clusters were observed during the early hours of maturation (1-4h); the majority of these were arranged in perinuclear fashion. LA supplementation resulted in: (1) delayed redistribution of the mitochondria from a peripheral to a diffuse pattern and a decreased percentages of oocytes showing perinuclear mitochondrial clusters, (2) decreased mitochondrial inner membrane potential at 1 and 24h compared with the control and (3) higher ROS levels, associated with a lower nuclear maturation rate. In contrast, ALA supplementation had no effect on mitochondrial distribution and activity and decreased ROS levels compared with the control; this was associated with an increased nuclear maturation rate. In conclusion, LA induced alterations in mitochondrial distribution and activity as well as increasing ROS levels, which mediate, at least in part, the inhibitory effect on oocyte maturation.

Dietary fatty acids modulate liver mitochondrial cardiolipin content and its fatty acid composition in rats with non alcoholic fatty liver disease

No data are reported on changes in mitochondrial membrane phospholipids in non-alcoholic fatty liver disease. We determined the content of mitochondrial membrane phospholipids from rats with non alcoholic liver steatosis, with a particular attention for cardiolipin (CL) content and its fatty acid composition, and their relation with the activity of the mitochondrial respiratory chain complexes. Different dietary fatty acid patterns leading to steatosis were explored. With high-fat diet, moderate macrosteatosis was observed and the liver mitochondrial phospholipid class distribution and CL fatty acids composition were modified. Indeed, both CL content and its C18:2n-6 content were increased with liver steatosis. Moreover, mitochondrial ATP synthase activity was positively correlated to the total CL content in liver phospholipid and to CL C18:2n-6 content while other complexes activity were negatively correlated to total CL content and/or CL C18:2n-6 content of liver mitochondria. The lard-rich diet increased liver CL synthase gene expression while the fish oil-rich diet increased the (n-3) polyunsaturated fatty acids content in CL. Thus, the diet may be a significant determinant of both the phospholipid class content and the fatty acid composition of liver mitochondrial membrane, and the activities of some of the respiratory chain complex enzymes may be influenced by dietary lipid amount in particular via modification of the CL content and fatty acid composition in phospholipid.

Rat liver mitochondrial membrane characteristics and mitochondrial functions are more profoundly altered by dietary lipid quantity than by dietary lipid quality: effect of different nutritional lipid patterns

Dietary lipids are known to affect the composition of the biological membrane and functions that are involved in cell death and survival. The mitochondrial respiratory chain enzymes are membrane protein complexes whose function depends on the composition and fluidity of the mitochondrial membrane lipid. The present study aimed at investigating the impact of different nutritional patterns of dietary lipids on liver mitochondrial functions. A total of forty-eight Wistar male rats were divided into six groups and fed for 12 weeks with a basal diet, lard diet or fish oil diet, containing either 50 or 300 g lipid/kg. The 30 % lipid intake increased liver NEFA, TAG and cholesterol levels, increased mitochondrial NEFA and TAG, and decreased phospholipid (PL) levels. SFA, PUFA and unsaturation index (UI) increased, whereas MUFA and trans-fatty acids (FA) decreased in the mitochondrial membrane PL in 30 % fat diet-fed rats compared with 5 % lipid diet-fed rats. PL UI increased with fish oil diet v. basal and lard-rich diets, and PL trans-FA increased with lard diet v. basal and fish oil diets. The 30 % lipid diet intake increased mitochondrial membrane potential, membrane fluidity, mitochondrial respiration and complex V activity, and decreased complex III and IV activities. With regard to lipid quality effects, β-oxidation decreased with the intake of basal or fish oil diets compared with that of the lard diet. The intake of a fish oil diet decreased complex III and IV activities compared with both the basal and lard diets. In conclusion, the characteristics and mitochondrial functions of the rat liver mitochondrial membrane are more profoundly altered by the quantity of dietary lipid than by its quality, which may have profound impacts on the pathogenesis and development of non-alcoholic fatty liver disease.

Age-related changes in brain mitochondrial DNA deletion and oxidative stress are differentially modulated by dietary fat type and coenzyme Q₁₀

Mitochondria-related oxidative damage is a primary event in aging and age-related neurodegenerative disorders. Some dietary treatments, such as antioxidant supplementation or the enrichment of mitochondrial membranes with less oxidizable fatty acids, reduce lipid peroxidation and lengthen life span in rodents. This study compares life-long feeding on monounsaturated fatty acids (MUFAs), such as virgin olive oil, and n-6 polyunsaturated fatty acids, such as sunflower oil, with or without coenzyme Q₁₀ supplementation, with respect to age-related molecular changes in rat brain mitochondria. The MUFA diet led to diminished age-related phenotypic changes, with lipoxidation-derived protein markers being higher among the older animals, whereas protein carbonyl compounds were lower. It is noteworthy that the MUFA diet prevented the age-related increase in levels of mitochondrial DNA deletions in the brain mitochondria from aged animals. The findings of this study suggest that age-related oxidative stress is related, at the mitochondrial level, to other age-related features such as mitochondrial electron transport and mtDNA alterations, and it can be modulated by selecting an appropriate dietary fat type and/or by suitable supplementation with low levels of the antioxidant/electron carrier molecule coenzyme Q.

Lipidomics profiling by high-resolution LC-MS and high-energy collisional dissociation fragmentation: focus on characterization of mitochondrial cardiolipins and monolysocardiolipins

A liquid chromatography-mass spectrometry (LC-MS) method was used for separation of lipid classes as well as both qualitative and semiquantitative detection of individual lipids in biological samples. Data were acquired using high-resolution full-scan MS and high-energy collisional dissociation (HCD) all ion fragmentation. The method was evaluated for efficient separation and detection in both positive and negative ionization mode using standards spanning six lipid classes. Platform linearity and robustness, related to the mitochondrial lipid cardiolipin (CL), were assessed using extracted ion chromatograms with mass tolerance windows of 5 ppm or less from full scan exact mass measurements. The platform CL limit of detection was determined to be 5 pmol (0.9 μM) on the column, with mass accuracy <1.5 ppm, retention time coefficients of variation (CV) < 0.5%, and area CV < 13%. This mass accuracy was critical to the identification of unknown CL species in mitochondria samples, through the elimination of false positives. In addition to detection and relative quantitation of CL species in mitochondria, CL structures were characterized through the use of alternating HCD scans at different energies to produce diagnostic fragmentations on all ions in the analysis. The developed lipid profiling method was applied to mitochondrial samples from an animal study related to the linkages between diet, mitochondrial function, and disease. The analysis identified 28 unique CL species and two monolysocardiolipin species that are often associated with mitochondrial stress and dysfunction.

Complex I-associated hydrogen peroxide production is decreased and electron transport chain enzyme activities are altered in n-3 enriched fat-1 mice

The polyunsaturated nature of n-3 fatty acids makes them prone to oxidative damage. However, it is not clear if n-3 fatty acids are simply a passive site for oxidative attack or if they also modulate mitochondrial reactive oxygen species (ROS) production. The present study used fat-1 transgenic mice, that are capable of synthesizing n-3 fatty acids, to investigate the influence of increases in n-3 fatty acids and resultant decreases in the n-6:n-3 ratio on liver mitochondrial H(2)O(2) production and electron transport chain (ETC) activity. There was an increase in n-3 fatty acids and a decrease in the n-6:n-3 ratio in liver mitochondria from the fat-1 compared to control mice. This change was largely due to alterations in the fatty acid composition of phosphatidylcholine and phosphatidylethanolamine, with only a small percentage of fatty acids in cardiolipin being altered in the fat-1 animals. The lipid changes in the fat-1 mice were associated with a decrease (p<0.05) in the activity of ETC complex I and increases (p<0.05) in the activities of complexes III and IV. Mitochondrial H(2)O(2) production with either succinate or succinate/glutamate/malate substrates was also decreased (p<0.05) in the fat-1 mice. This change in H(2)O(2) production was due to a decrease in ROS production from ETC complex I in the fat-1 animals. These results indicate that the fatty acid changes in fat-1 liver mitochondria may at least partially oppose oxidative stress by limiting ROS production from ETC complex I.

Chemical characterization of Lycium barbarum polysaccharides and its inhibition against liver oxidative injury of high-fat mice

In this study, we investigated chemical structure of Lycium barbarum polysaccharides and its modulatory effect on oxidative stress in high-fat mice. The polysaccharides mainly contained xylose and glucose. Little amount of rhamnose, mannose and galactose was observed. The Lycium barbarum polysaccharides had IR bands at 800-1200 cm(-1), 1450-1800 cm(-1), 2500-3000 cm(-1), and 3200-3600 cm(-1), which were distinctive absorptions of polysaccharides. Rats are fed with high-fat diet for 2 months. Results showed that blood and liver antioxidant enzymes activities and GSH level in model mice significantly decreased, and MDA level significantly increased (P<0.01) compared to normal control mice. Administration of Lycium barbarum polysaccharides significantly increased antioxidant enzymes activities and decreased MDA level in mice (P<0.01) compared to model group.

Lipidomic profiling in mouse brain reveals differences between ages and genders, with smaller changes associated with alpha-synuclein genotype

Advances in lipidomics technology have facilitated the precise detection, identification and profiling of lipid species within tissues. Mass spectrometry allows for identification of lipids as a function of the total number of carbons and double bonds in their acyl chains. Such detailed descriptions of lipid composition can provide a basis for further investigation of cell signaling and metabolic pathways, both physiological and pathological. Here, we applied phospholipid profiling to mouse models relevant to Parkinson's disease, using mice that were transgenic for human alpha-synuclein (alphaSyn) or deleted of endogenous alphaSyn. Proposed functions of alphaSyn include phospholipid binding, regulation of membrane composition, and regulation of vesicular pools. We investigated whether alphaSyn gene dosage interacts with differences in phospholipid composition across brain regions or with age-related changes in brain phospholipid composition. The most dramatic phospholipid changes were observed in alphaSyn wild-type animals as a function of age and gender. alphaSyn genotype-specific changes were also observed in aged, but not young, mice. Our results provide a detailed and systematic characterization of brain phospholipid composition in mice and identify age-related changes relevant both to Parkinson's disease and to normal aging.

Hepatic gene expression profiles in juvenile rainbow trout (Oncorhynchus mykiss) fed fishmeal or fish oil-free diets

Reducing the reliance on fishery by-products as amino acid and fatty acid sources in feeds for farmed fish is a major objective today. We evaluated the effect of dietary fish oil or dietary fishmeal replacement by vegetable oils and plant proteins respectively through analysis of hepatic transcriptomes in rainbow trout (Oncorhynchus mykiss). Fish were fed right from first feeding with diets based on plant by-products before being killed. We analysed the hepatic gene profile using trout cDNA microarrays (9K). Our data showed that seventy-one and seventy-five genes were affected after fish oil and fishmeal replacement respectively. The major part of modified gene expression coding for proteins of the metabolic pathways was as follows: (i) a lower level of expression for genes of energy metabolism found in fish after fishmeal and fish oil replacement; (ii) a lower level of gene expression for fatty acid metabolism (biosynthesis) in fish fed with vegetable oils; (iii) a differential expression of actors of detoxification metabolism in trout fed with vegetable oils; (iv) a lower level of expression of genes involved in protein metabolism in fish fed with plant proteins. Overall, our data suggest that dietary fish oil replacement is linked to a decreased capacity of fatty acid biosynthesis (fatty acid synthase) and variation of detoxification metabolism (cytochrome P450s) whereas dietary fishmeal replacement may depress protein metabolism in the liver as reflected by glutamine synthetase.

The intake of fried virgin olive or sunflower oils differentially induces oxidative stress in rat liver microsomes

The effects of non-fried and fried virgin olive and sunflower oils on rat liver microsomal compositional features have been investigated. In addition, plasma antioxidants (α-tocopherol and ubiquinone 9) were investigated as well as the possible oxidative modifications suffered by virgin olive and sunflower oils during the frying process. The frying process decreased the content of α-tocopherol and phenolics in the oils and increased total polar materials. Sunflower oil was affected to a greater extent than olive oil. In rats, the intake of fried oil led to higher levels of lipid peroxidation and a lower concentration of plasma antioxidants. Microsomal fatty acid and antioxidant profiles were also altered. It seems that a strong relationship exists between the loss of antioxidants and the production of toxic compounds in the oils after frying and the extent of the peroxidative events in microsomes, which were also different depending on the fat source. The highly unsaturated sunflower oil was less resistant to the oxidative stress produced by frying and led to a higher degree of lipid peroxidation in liver microsomesin vivothan virgin olive oil.

Functioning of oxidative phosphorylation in liver mitochondria of high-fat diet fed rats

We proposed that inhibition of mitochondrial adenine nucleotide translocator (ANT) by long chain acyl-CoA (LCAC) underlies the mechanism associating obesity and type 2 diabetes. Here we test that after long-term exposure to a high-fat diet (HFD): (i) there is no adaptation of the mitochondrial compartment that would hinder such ANT inhibition, and (ii) ANT has significant control of the relevant aspects of oxidative phosphorylation. After 7 weeks, HFD induced a 24+/-6% increase in hepatic LCAC concentration and accumulation of the oxidative stress marker N(epsilon)-(carboxymethyl)lysine. HFD did not significantly affect mitochondrial copy number, oxygen uptake, membrane potential (Deltapsi), ADP/O ratio, and the content of coenzyme Q(9), cytochromes b and a+a(3). Modular kinetic analysis showed that the kinetics of substrate oxidation, phosphorylation, proton leak, ATP-production and ATP-consumption were not influenced significantly. After HFD-feeding ANT exerted considerable control over oxygen uptake (control coefficient C=0.14) and phosphorylation fluxes (C=0.15), extra- (C=0.23) and intramitochondrial (C=-0.56) ATP/ADP ratios, and Deltapsi (C=-0.11). We conclude that although HFD induces accumulation of LCAC and N(epsilon)-(carboxymethyl)lysine, oxidative phosphorylation does not adapt to these metabolic challenges. Furthermore, ANT retains control of fluxes and intermediates, making inhibition of this enzyme a more probable link between obesity and type 2 diabetes.

Improvement of visual functions and fundus alterations in early age-related macular degeneration treated with a combination of acetyl-L-carnitine, n-3 fatty acids, and coenzyme Q10

The aim of this randomized, double-blind, placebo-controlled clinical trial was to determine the efficacy of a combination of acetyl-L-carnitine, n-3 fatty acids, and coenzyme Q10 (Phototrop) on the visual functions and fundus alterations in early age-related macular degeneration (AMD). One hundred and six patients with a clinical diagnosis of early AMD were randomized to the treated or control groups. The primary efficacy variable was the change in the visual field mean defect (VFMD) from baseline to 12 months of treatment, with secondary efficacy parameters: visual acuity (Snellen chart and ETDRS chart), foveal sensitivity as measured by perimetry, and fundus alterations as evaluated according to the criteria of the International Classification and Grading System for AMD. The mean change in all four parameters of visual functions showed significant improvement in the treated group by the end of the study period. In addition, in the treated group only 1 out of 48 cases (2%) while in the placebo group 9 out of 53 (17%) showed clinically significant (>2.0 dB) worsening in VFMD (p = 0.006, odds ratio: 10.93). Decrease in drusen-covered area of treated eyes was also statistically significant as compared to placebo when either the most affected eyes (p = 0.045) or the less affected eyes (p = 0.017) were considered. These findings strongly suggested that an appropriate combination of compounds which affect mitochondrial lipid metabolism, may improve and subsequently stabilize visual functions, and it may also improve fundus alterations in patients affected by early AMD.

Ageing and the Mediterranean diet: a review of the role of dietary fats

Consumers are becoming increasingly aware of the relationship between food and health. Concerns have been raised about dietary fats and their relative nutritional advantages or disadvantages. In investigations of the associations between health and fat intake, special emphasis has been placed on the benefits of virgin olive oil for counteracting certain neurodegenerative diseases and ageing. With respect to ageing, accumulating evidence indicates that an improvement in quality of life can be reached by modulation of the extrinsic factors that influence many ageing processes. Of the modifiable factors, nutrition appears to be one of the strongest elements known to influence the rate of ageing as well as the incidence of age-associated diseases such as atherosclerosis and neurodegenerative pathologies. This paper reviews the theory of ageing and the role of fatty acids in the mechanisms affecting its evolution. It also confirms that virgin olive oil, an essential component of the Mediterranean diet, provides large amounts of stable and not easily oxidizable fatty acids as well as remarkable quantities of powerful antioxidant molecules.

Influence of mitochondrial membrane fatty acid composition on proton leak and H2O2 production in liver

Mitochondrial membrane fatty acid composition has been proposed to play a role in determining mitochondrial proton leak rate. The purpose of this study was to determine if feeding rats diets with different fatty acid sources produces changes in liver proton leak and H(2)O(2) production. Six-month-old male FBNF(1) rats were fed diets with a primary fat source of either corn or fish oil for a 6-month period. As expected, diet manipulations produced substantial differences in mitochondrial fatty acid composition. These changes were most striking for 20:4n6 and 22:6n3. However, proton leak and phosphorylation kinetics as well as lipid and protein oxidative damage were not different (P > 0.10) between fish and corn oil groups. Metabolic control analysis, however, did show that control of both substrate oxidation and phosphorylation was shifted away from substrate oxidation reactions to increased control by phosphorylation reactions in fish versus corn oil groups. Increased mitochondrial H(2)O(2) production was observed in corn versus fish oil-fed rats when mitochondria were respiring on succinate alone or on either succinate or pyruvate/malate in the presence of antimycin A. These results show that mitochondrial H(2)O(2) production and the regulation of oxidative phosphorylation are altered in liver mitochondria from rats consuming diets with either fish or corn oil as the primary lipid source.

Mitochondrial dysfunctions during aging: vitamin E deficiency or caloric restriction--two different ways of modulating stress

Caloric restriction (CR), which has been demonstrated to offset the age-associated accrual of oxidative injury, involves a reduction in calory intake while maintaining adequate nutrition, preserves the activities of antioxidant enzymes in postmitotic tissues, maintains organ function, opposes the development of spontaneous diseases, and prolongs maximum life span in laboratory rodents. It has been proposed that reductions in Reactive Oxygen Species (ROS) production and cellular oxidative injury are central to the positive effects of CR. In the present investigation we studied the effect of CR and of a vitamin E deprived diet on mitochondrial structure and features in the liver of rats during aging, in order to ascertain the extent of modifications induced by these experimental conditions. CR rats displayed structural and functional mitochondrial properties (fatty acid pattern, respiratory chain activities, antioxidant levels, and hydroperoxide contents) similar to those of younger rats whilst vitamin E deficient rats appeared older than their own age. The mitochondria of the former, together with those of young rats, possessed the lowest Coenzyme Q9, hydroperoxide, and cytochrome contents as well as a suitable fatty acid membrane composition. Our study confirms that CR is a valuable tool in limiting aging-related free-radical damage also at mitochondrial liver level.

Glucose transport and utilization are altered in the brain of rats deficient in n-3 polyunsaturated fatty acids

Long-chain polyunsaturated (n-3) fatty acids have been reported to influence the efficiency of membrane receptors, transporters and enzymes. Because the brain is particularly rich in docosahexaenoic acid (DHA, 22:6 n-3), the present study addresses the question of whether the 22:6 n-3 fatty acid deficiency induces disorder in regulation of energy metabolism in the CNS. Three brain regions that share a high rate of energy metabolism were studied: fronto-parietal cortex, hippocampus and suprachiasmatic nucleus. The effect of the diet deficient in n-3 fatty acids resulted in a 30-50% decrease in DHA in membrane phospholipids. Moreover, a 30% decrease in glucose uptake and a 20-40% decrease in cytochrome oxidase activity were observed in the three brain regions. The n-3 deficient diet also altered the immunoreactivity of glucose transporters, namely GLUT1 in endothelial cells and GLUT3 in neurones. In n-3 fatty acid deficient rats, GLUT1-immunoreactivity readily detectable in microvessels became sparse, whereas the number of GLUT3 immunoreactive neurones was increased. However, western blot analysis showed no significant difference in GLUT1 and GLUT3 protein levels between rats deficient in n-3 fatty acids and control rats. The present results suggest that changes in energy metabolism induced by n-3 deficiency could result from functional alteration in glucose transporters.

Feeding fried oil changes antioxidant and fatty acid pattern of rat and affects rat liver mitochondrial respiratory chain components

Fat frying is a popular food preparation method but several components like antioxidant vitamins could be lost due to oxidation and some others with toxic effects could appear. Because of such large consumption of frying oils, the effect of high temperatures on the oils is of major concern both for product quality and nutrition, taking into account that dietary fat source deeply influences several biochemical parameters, especially of mitochondrial membranes. Virgin olive oil possesses specific features for modulating the damages occurred by endogenous and exogenous oxidative stress being particularly rich in antioxidant molecules. We evaluated the extent of modifications suffered by virgin olive oil following a short-time deep fat frying procedure: vitamin E and phenolic compound as well as total antioxidant capacity (measured by ESR) decreased, while polar compounds increased. The intake of such an altered oil mainly affected the hydroperoxide and TBARS contents of mitochondrial membranes which were enhanced after the dietary treatments. Also, several mitochondrial respiratory chain components (Coenzyme Q, cytochrome b, c + c1, and a + a3) were affected.

Dietary fat type and regular exercise affect mitochondrial composition and function depending on specific tissue in the rat

Physical exercise and fatty acids have been studied in relation to mitochondrial composition and function in rat liver, heart, and skeletal muscle. Male rats were divided into two groups according to dietary fat type (virgin olive and sunflower oils). One-half of the animals from each group were subjected to a submaximal exercise for 8 weeks; the other half acted as sedentary controls. Coenzyme Q, cytochromes b, c + c1, a + a3 concentrations, and the activity of cytochrome c oxidase were determined. Regular exercise increased (P < 0.05) the concentration of the above-mentioned elements and the activity of the cytochrome c oxidase by roughly 50% in liver and skeletal muscle. In contrast, physical exercise decreased (P < 0.05) cytochrome c oxidase activity in the heart (in micromol/min/g, from 8.4+/-0.1 to 4.9+/-0.1 in virgin olive oil group and from 9.7+/-0.1 to 6.7+/-0.2 in sunflower oil animals). Dietary fat type raised the levels of coenzyme Q, cytochromes, and cytochrome c oxidase activity in skeletal muscle (P < 0.05) among the rats fed sunflower oil. In conclusion, dietary fat type, regular exercise, and the specific tissue modulate composition and function of rat mitochondria.

Effect of docosahexaenoic acid on mouse mitochondrial membrane properties

Long-chain polyunsaturated (n-3) fatty acids have been proposed to be involved in a wide variety of biological activities. In this study, mitochondrial docosahexaenoic acid (DHA) levels were increased by either dietary manipulation or by fusing the mitochondria with phospholipid vesicles made from 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine (18:0/22:6 PC). The fused mitochondria exhibited a DHA-induced decrease in respiratory control index (RCI) and membrane potential and an increase in proton movement. The modified mitochondria also demonstrated an increase in fluidity (as detected by 1,6-diphenyl-1,3,5-hexatriene anisotropy) and changes in membrane structure detected by the fluorescence probes MC540 and pyrene decanoate. Proton movement in lipid vesicles made from mitochondrial lipid extracts was shown to be enhanced by incorporated 18:0/22:6 PC. Mitochondria were isolated from young (5-mon) and old (24-mon) mice which were maintained on either a diet rich in saturated fats (hydrogenated coconut oil) or rich in n-3 polyunsaturated fats (menhaden oil). Mitochondrial bioenergetic function was followed by RCI, state 3 respiration, ATP level, and phosphate uptake. In addition, lipid composition, phospholipid area/molecule and extent of lipid peroxidation were also determined. Decreases in RCI for the menhaden oil diet-modified mitochondria paralleled those in which DHA levels were enhanced by fusion with phospholipid vesicles. RCI reductions are attributed to DHA-induced increases in H+ movement, producing diminished mitochondrial membrane potentials. One purpose of this project was to determine if the deleterious effects of aging on mitochondrial bioenergetic function could be reversed by addition of n-3 fatty acids. The experiments reported here indicate that incorporation of long-chain polyunsaturated n-3 fatty acids into mitochondrial membranes does not appear likely to reverse the effects of age on mitochondrial function.

Effect of diets containing different amounts of precursor and derivative fatty acids on serum TXB2

Dietary precursor and derivative polyunsaturated fatty acids influence metabolic parameters, such as eicosanoid synthesis. We have studied the effect of dietary intakes of lipids containing different amounts of precursor and derivative fatty acids (olive oil, olive-blackcurrant-fish oil mixture, blackcurrant-fish oil mixture, MCT (medium chain triglycerides)-soyabean oil mixture) on serum thromboxane B2 (TXB2) in four groups of rats. Plasma fatty acid composition showed differences related to dietary intakes. TXB2 levels were similar in all conditions except in the group receiving the mixture of olive-blackcurrant-fish oils which showed lower values.