Virgin olive oil and coenzyme Q10 protect heart mitochondria from peroxidative damage during aging

Biomarkers of lung alveolarization and microvascular maturation in response to intermittent hypoxia and/or early antioxidant/fish oil supplementation in neonatal rats

OBJECTIVE

Extremely preterm infants experience frequent intermittent hypoxia (IH) episodes during oxygen therapy which causes significant damage to the lungs and curtails important signaling pathways that regulate normal lung alveolarization and microvascular maturation. We tested the hypothesis that early supplementation with fish oil and/or antioxidants in rats exposed to neonatal IH improves expression of lung biomarkers of alveolarization and microvascular maturation, and reduces IH-induced lung injury.

STUDY DESIGN/METHODS

From birth (P0) to P14, rat pups were exposed to room air (RA) or neonatal IH during which they received daily oral supplementation with either: (1) olive oil (OO) (control); (2) Coenzyme Q10 (CoQ10) in OO; (3) fish oil; (4) glutathione nanoparticles (nGSH); or (5) fish oil +CoQ10. At P14 pups were placed in RA until P21 with no further treatment. RA controls were similarly treated. Lung growth and alveolarization, histopathology, apoptosis, oxidative stress and biomarkers of alveolarization and microvascular maturation were determined.

RESULTS

Neonatal IH was associated with reduced lung weights and severe histopathological outcomes. These effects were curtailed with fish oil and nGSH. nGSH was also protective against apoptosis, while CoQ10 prevented IH-induced ROS production. Of all treatments, nGSH and CoQ10 + fish oil-induced vascular endothelial growth factor165 and CD31 (Platelet endothelial cell adhesion molecule-1), which are associated with angiogenesis. CoQ10 + fish oil improved alveolarization in RA and IH despite evidence of hemorrhage.

CONCLUSIONS

The benefits of nGSH and CoQ10 + fish oil suggest an antioxidant effect which may be required to curtail IH-induced lung injury. Further clinical assessment of the effectiveness of nGSH is warranted.

Dietary antioxidants and lifespan: Relevance of environmental conditions, diet, and genotype of experimental models

The rise of life expectancy in current societies is not accompanied, to date, by a similar increase in healthspan, which represents a great socio-economic problem. It has been suggested that aging can be manipulated and then, the onset of all age-associated chronic disorders can be delayed because these pathologies share age as primary underlying risk factor. One of the most extended ideas is that aging is consequence of the accumulation of molecular damage. According to the oxidative damage theory, antioxidants should slow down aging, extending lifespan and healthspan. The present review analyzes studies evaluating the effect of dietary antioxidants on lifespan of different aging models and discusses the evidence on favor of their antioxidant activity as anti-aging mechanisms. Moreover, possible causes for differences between the reported results are evaluated.

Neonatal intermittent hypoxia, fish oil, and/or antioxidant supplementation on gut microbiota in neonatal rats

BACKGROUND

Preterm infants frequently experience intermittent hypoxia (IH) episodes, rendering them susceptible to oxidative stress and gut dysbiosis. We tested the hypothesis that early supplementation with antioxidants and/or fish oil promotes gut biodiversity and mitigates IH-induced gut injury.

METHODS

Newborn rats were exposed to neonatal IH from birth (P0) to P14 during which they received daily oral supplementation with: (1) coenzyme Q10 (CoQ10) in olive oil, (2) fish oil, (3) glutathione nanoparticles (nGSH), (4) CoQ10 + fish oil, or (5) olive oil (placebo control). Pups were placed in room air (RA) from P14 to P21 with no further treatment. RA controls were similarly treated. Stool samples were assessed for microbiota and terminal ileum for histopathology and morphometry, total antioxidant capacity, lipid peroxidation, and biomarkers of gut injury.

RESULTS

Neonatal IH induced histopathologic changes consistent with necrotizing enterocolitis, which were associated with increased lipid peroxidation, toll-like receptor, transforming growth factor, and nuclear factor kappa B. Combination of CoQ10 + fish oil and nGSH were most effective for preserving gut integrity, reducing biomarkers of gut injury, and increasing commensal organisms.

CONCLUSIONS

Combination of antioxidants and fish oil may confer synergistic benefits to mitigate IH-induced injury in the terminal ileum.

IMPACT

Antioxidant and fish oil (PUFA) co-treatment was most beneficial for reducing neonatal IH-induced gut injury. The synergistic effects of antioxidant and fish oil is likely due to prevention of IH-induced ROS attack on lipids, thus preserving and augmenting its therapeutic benefits. Combination treatment was also effective for increasing the abundance of the non-pathogenic Firmicutes phylum, which is associated with a healthy gastrointestinal system of the newborn. Extremely low gestational age neonates who are at high risk for frequent, repetitive neonatal IH and oxidative stress-induced diseases may benefit from this combination therapy.

Oleic Acid Prevents Isoprenaline-Induced Cardiac Injury: Effects on Cellular Oxidative Stress, Inflammation and Histopathological Alterations

The present study was designed to assess the cardio-protective role of oleic acid in myocardial injury (MI) induced by intra-peritoneal injection of isoprenaline (ISO) in rats for 2 consecutive days. Oleic acid (OA) was administered orally (@ 5 mg/kg b.wt and 10 mg/kg b.wt) for 21 days before inducing MI. Pre-exposure to OA at higher dose significantly improved the HW/BW ratio, myocardial infarct size, lipid profiles (total cholesterol, HDL-C) and cardiac injury biomarkers (LDH, CK-MB, cardiac troponin-I, MMP-9), thus suggesting its cardio-protective role. The ameliorative potential of the higher dose of OA was further substantiated by its ability to reduce the cardiac oxidative stress as evidenced by significant decrease in lipid peroxidation coupled with increase in superoxide dismutase activity and reduced glutathione level. Significant decrease in heart rate as well as increase in RR and QT intervals in oleic acid pre-exposed rats were also observed. OA pre-treatment also reduced the histopathological alterations seen in myocardial injury group rats. The mRNA expression of cardiac UCP-2 gene, a regulator of reactive oxygen species (ROS) generation, was significantly increased in oleic acid pre-exposure group compared to the ISO-induced myocardial injury group. Thus increase in expression of UCP-2 gene in cardiac tissue seems to be one of the protective measures against myocardial injury. Based on the above findings, it may be inferred that oleic acid possesses promising cardio-protective potential against myocardial injury due to its anti-oxidative property and ability to modulate cardiac metabolic processes.

The Paradox of Coenzyme Q10 in Aging

Coenzyme Q (CoQ) is an essential endogenously synthesized molecule that links different metabolic pathways to mitochondrial energy production thanks to its location in the mitochondrial inner membrane and its redox capacity, which also provide it with the capability to work as an antioxidant. Although defects in CoQ biosynthesis in human and mouse models cause CoQ deficiency syndrome, some animals models with particular defects in the CoQ biosynthetic pathway have shown an increase in life span, a fact that has been attributed to the concept of mitohormesis. Paradoxically, CoQ levels decline in some tissues in human and rodents during aging and coenzyme Q₁₀ (CoQ₁₀) supplementation has shown benefits as an anti-aging agent, especially under certain conditions associated with increased oxidative stress. Also, CoQ₁₀ has shown therapeutic benefits in aging-related disorders, particularly in cardiovascular and metabolic diseases. Thus, we discuss the paradox of health benefits due to a defect in the CoQ biosynthetic pathway or exogenous supplementation of CoQ₁₀.

Age-Related Loss in Bone Mineral Density of Rats Fed Lifelong on a Fish Oil-Based Diet Is Avoided by Coenzyme Q10 Addition

During aging, bone mass declines increasing osteoporosis and fracture risks. Oxidative stress has been related to this bone loss, making dietary compounds with antioxidant properties a promising weapon. Male Wistar rats were maintained for 6 or 24 months on diets with fish oil as unique fat source, supplemented or not with coenzyme Q10 (CoQ10), to evaluate the potential of adding this molecule to the n-3 polyunsaturated fatty acid (n-3 PUFA)-based diet for bone mineral density (BMD) preservation. BMD was evaluated in the femur. Serum osteocalcin, osteopontin, receptor activator of nuclear factor-κB ligand, ostroprotegerin, parathyroid hormone, urinary F₂-isoprostanes, and lymphocytes DNA strand breaks were also measured. BMD was lower in aged rats fed a diet without CoQ10 respect than their younger counterparts, whereas older animals receiving CoQ10 showed the highest BMD. F₂-isoprostanes and DNA strand breaks showed that oxidative stress was higher during aging. Supplementation with CoQ10 prevented oxidative damage to lipid and DNA, in young and old animals, respectively. Reduced oxidative stress associated to CoQ10 supplementation of this n-3 PUFA-rich diet might explain the higher BMD found in aged rats in this group of animals.

Role of Lipids in the Onset, Progression and Treatment of Periodontal Disease. A Systematic Review of Studies in Humans

The risk of different oral problems (root caries, tooth mobility, and tooth loss) can be increased by the presence of periodontal disease, which has also been associated with a growing list of systemic diseases. The presence of some bacteria is the primary etiology of this disease; a susceptible host is also necessary for disease initiation. In this respect, the progression of periodontal disease and healing of the periodontal tissues can be modulated by nutritional status. To clarify the role of lipids in the establishment, progression, and/or treatment of this pathology, a systematic review was conducted of English-written literature in PubMed until May 2016, which included research on the relationship of these dietary components with the onset and progression of periodontal disease. According to publication type, randomized-controlled trials, cohort, case-control and cross-sectional studies were included. Among all the analyzed components, those that have any effect on oxidative stress and/or inflammation seem to be the most interesting according to current evidence. On one hand, there is quite a lot of information in favor of a positive role of n-3 fatty acids, due to their antioxidant and immunomodulatory effects. On the other hand, saturated fat-rich diets increase oxidative stress as well the as intensity and duration of inflammatory processes, so they must be avoided.

Coenzyme Q and Its Role in the Dietary Therapy against Aging

Coenzyme Q (CoQ) is a naturally occurring molecule located in the hydrophobic domain of the phospholipid bilayer of all biological membranes. Shortly after being discovered, it was recognized as an essential electron transport chain component in mitochondria where it is particularly abundant. Since then, more additional roles in cell physiology have been reported, including antioxidant, signaling, death prevention, and others. It is known that all cells are able to synthesize functionally sufficient amounts of CoQ under normal physiological conditions. However, CoQ is a molecule found in different dietary sources, which can be taken up and incorporated into biological membranes. It is known that mitochondria have a close relationship with the aging process. Additionally, delaying the aging process through diet has aroused the interest of scientists for many years. These observations have stimulated investigation of the anti-aging potential of CoQ and its possible use in dietary therapies to alleviate the effects of aging. In this context, the present review focus on the current knowledge and evidence the roles of CoQ cells, its relationship with aging, and possible implications of dietary CoQ in relation to aging, lifespan or age-related diseases.

Sunflower Oil but Not Fish Oil Resembles Positive Effects of Virgin Olive Oil on Aged Pancreas after Life-Long Coenzyme Q Addition

An adequate pancreatic structure is necessary for optimal organ function. Structural changes are critical in the development of age-related pancreatic disorders. In this context, it has been reported that different pancreatic compartments from rats were affected according to the fat composition consumed. Since there is a close relationship between mitochondria, oxidative stress and aging, an experimental approach has been developed to gain more insight into this process in the pancreas. A low dosage of coenzyme Q was administered life-long in rats in order to try to prevent pancreatic aging-related alterations associated to some dietary fat sources. According to that, three groups of rats were fed normocaloric diets containing Coenzyme Q (CoQ) for two years, where virgin olive, sunflower, or fish oil was included as unique fat source. Pancreatic samples for microscopy and blood samples were collected at the moment of euthanasia. The main finding is that CoQ supplementation gives different results according to fat used in diet. When sunflower oil was the main fat in the diet, CoQ supplementation seems to improve endocrine pancreas structure and in particular β-cell mass resembling positive effects of virgin olive oil. Conversely, CoQ intake does not seem to improve the structural alterations of exocrine compartment previously observed in fish oil fed rats. Therefore CoQ may improve pancreatic alterations associated to the chronic intake of some dietary fat sources.

Oxidative Stress and Dietary Fat Type in Relation to Periodontal Disease

Oxidative stress is one of the main factors studied to explain the pathophysiological mechanisms of inflammatory conditions, such as periodontitis. In this respect, nutrition may be of great importance. Actually, research on nutrients' effects on periodontal diseases has expanded to include those influencing the redox status, which correlates to the inflammatory process. Dietary fat or lipids are often blamed as the major source of excess energy. Consequently, when caloric intake exceeds energy expenditure, the resultant substrate-induced increase in citric acid cycle activity generates an excess of reactive oxygen species (ROS). In addition, dietary fatty acid intake influences in relative fatty acid composition of biological membranes determining its susceptibility to oxidative alterations. From this standpoint, here, we reviewed studies analyzing the dietary fat role in periodontal disease. Research data suggest that periodontal health could be achieved by main dietary strategies which include substitution of saturated fats with monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), particularly n-3 PUFA. Maybe in the future, we should analyze the diet and provide some advice to periodontitis patients to improve treatment outcomes.

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.

The Influence of Dietary Fat Source on Life Span in Calorie Restricted Mice

Calorie restriction (CR) without malnutrition extends life span in several animal models. It has been proposed that a decrease in the amount of polyunsaturated fatty acids (PUFAs), and especially n-3 fatty acids, in membrane phospholipids may contribute to life span extension with CR. Phospholipid PUFAs are sensitive to dietary fatty acid composition, and thus, the purpose of this study was to determine the influence of dietary lipids on life span in CR mice. C57BL/6J mice were assigned to four groups (a 5% CR control group and three 40% CR groups) and fed diets with soybean oil (high in n-6 PUFAs), fish oil (high in n-3 PUFAs), or lard (high in saturated and monounsaturated fatty acids) as the primary lipid source. Life span was increased (p < .05) in all CR groups compared to the Control mice. Life span was also increased (p < .05) in the CR lard mice compared to animals consuming either the CR fish or soybean oil diets. These results indicate that dietary lipid composition can influence life span in mice on CR, and suggest that a diet containing a low proportion of PUFAs and high proportion of monounsaturated and saturated fats may maximize life span in animals maintained on CR.

Coenzyme Q10 prevents accelerated cardiac aging in a rat model of poor maternal nutrition and accelerated postnatal growth

Studies in human and animals have demonstrated that nutritionally induced low birth-weight followed by rapid postnatal growth increases the risk of metabolic syndrome and cardiovascular disease. Although the mechanisms underlying such nutritional programming are not clearly defined, increased oxidative-stress leading to accelerated cellular aging has been proposed to play an important role. Using an established rodent model of low birth-weight and catch-up growth, we show here that post-weaning dietary supplementation with coenzyme Q10, a key component of the electron transport chain and a potent antioxidant rescued many of the detrimental effects of nutritional programming on cardiac aging. This included a reduction in nitrosative and oxidative-stress, telomere shortening, DNA damage, cellular senescence and apoptosis. These findings demonstrate the potential for postnatal antioxidant intervention to reverse deleterious phenotypes of developmental programming and therefore provide insight into a potential translatable therapy to prevent cardiovascular disease in at risk humans.

Effect of POLY-MVA, a palladium alpha-lipoic acid complex formulation against declined mitochondrial antioxidant status in the myocardium of aged rats

Palladium alpha-lipoic acid formulation--'POLY-MVA' is found to enhance the activities of Krebs cycle dehydrogenases and respiratory complexes in the heart of aged rat. In this study, we aimed to evaluate the effect of POLY-MVA on the activities of antioxidant status in the heart mitochondria of aged rat. We determined the activities of manganese-superoxide dismutase (Mn SOD), catalase (CAT), glutathione peroxidase (GPx), and level of reduced GSH and lipid peroxidation in the heart mitochondria of aged rats, after administering POLY-MVA (0.05 ml/kg; equivalent to 0.38 mg complexed alpha-lipoic acid/kg) orally once daily for 30 days. DL-alpha-lipoic acid (0.38 mg/kg, p.o) treated for 30 days was kept as the positive control. We found that the antioxidant in the aged control was declined significantly than the young control. The formulation significantly (p<0.05) enhanced the activity of CAT and GPx compared to the aged control. The level of GSH was also significantly improved and the level of lipid peroxidation was decreased significantly (p<0.05) by POLY-MVA. The results indicate that POLY-MVA is effective to protect the age-linked decline of myocardial mitochondrial antioxidant status. The findings suggest the use of this formulation against myocardial aging.

Is coenzyme Q a key factor in aging?

Coenzyme Q (Q) is a key component for bioenergetics and antioxidant protection in the cell. During the last years, research on diseases linked to Q-deficiency has highlighted the essential role of this lipid in cell physiology. Q levels are also affected during aging and neurodegenerative diseases. Therefore, therapies based on dietary supplementation with Q must be considered in cases of Q deficiency such as in aging. However, the low bioavailability of dietary Q for muscle and brain obligates to design new mechanisms to increase the uptake of this compound in these tissues. In the present review we show a complete picture of the different functions of Q in cell physiology and their relationship to age and age-related diseases. Furthermore, we describe the problems associated with dietary Q uptake and the mechanisms currently used to increase its uptake or even its biosynthesis in cells. Strategies to increase Q levels in tissues are indicated.

Coenzyme Q supplementation protects from age-related DNA double-strand breaks and increases lifespan in rats fed on a PUFA-rich diet

This study investigates the usefulness of a long-term supplementation with coenzyme Q(10) in rats from the point of view of lifespan, DNA double-strand breaks and to assess whether this supplementation might attenuate oxidative alterations related to PUFA-rich diets, which would allow to preserve beneficial aspects of PUFA on health avoiding their deleterious aspects. Supplemented animals showed higher concentration of coenzyme Q(10) in liver mitochondria, lower levels of DNA double-strand breaks in peripheral blood lymphocytes. Animals supplemented on coenzyme Q reached a significantly higher mean life span (11,7% higher, i.e. 2,5 months) and a significantly higher maximum life span (24% higher, i.e. 6 months) than non-supplemented animals. These results suggest that a long-term supplementation with a small dosage of coenzyme Q(10) might represent a good anti-aging therapy in rats fed on a PUFA-based diet.

Mitochondrial production of oxygen radical species and the role of Coenzyme Q as an antioxidant

The mitochondrial respiratory chain is a powerful source of reactive oxygen species (ROS), which is considered as the pathogenic agent of many diseases and of aging. We have investigated the role of complex I in superoxide radical production and found by the combined use of specific inhibitors of complex I that the one-electron donor to oxygen in the complex is a redox center located prior to the sites where three different types of Coenzyme Q (CoQ) competitors bind, to be identified with an Fe-S cluster, most probably N2, or possibly an ubisemiquinone intermediate insensitive to all the above inhibitors. Short-chain Coenzyme Q analogs enhance superoxide formation, presumably by mediating electron transfer from N2 to oxygen. The clinically used CoQ analog, idebenone, is particularly effective, raising doubts on its safety as a drug. Cells counteract oxidative stress by antioxidants. CoQ is the only lipophilic antioxidant to be biosynthesized. Exogenous CoQ, however, protects cells from oxidative stress by conversion into its reduced antioxidant form by cellular reductases. The plasma membrane oxidoreductase and DT-diaphorase are two such systems, likewise, they are overexpressed under oxidative stress conditions.

Role of mitochondria in oxidative stress and aging

The mitochondrial respiratory chain is a powerful source of reactive oxygen species (ROS), considered as the pathogenic agent of many diseases and of aging. We have investigated the role of Complex I in superoxide radical production and found by combined use of specific inhibitors of Complex I that the one-electron donor in the Complex to oxygen is a redox center located prior to the sites where three different types of coenzyme Q (CoQ) competitors bind, to be identified with an Fe-S cluster, most probably N2, or possibly an ubisemiquinone intermediate insensitive to all the above inhibitors. Short-chain coenzyme Q analogues enhance superoxide formation, presumably by mediating electron transfer from N2 to oxygen. The clinically used CoQ analogue idebenone is particularly effective, raising doubts about its safety as a drug. The mitochondrial theory of aging considers somatic mutations of mitochondrial DNA induced by ROS as the primary cause of energy decline; in rat liver mitochondria, Complex I appears to be most affected by aging and to become strongly rate limiting for electron transfer. Mitochondrial energetics is also deranged in human platelets upon aging, as demonstrated by the decreased Pasteur effect (enhancement of lactate production by respiratory inhibitors). Cells counteract oxidative stress by antioxidants: CoQ is the only lipophilic antioxidant to be biosynthesized. Exogenous CoQ, however, protects cells from oxidative stress by conversion into its reduced antioxidant form by cellular reductases. The plasma membrane oxidoreductase and DT-diaphorase are two such systems: likewise, they are overexpressed under oxidative stress conditions.

Feeding acetyl-L-carnitine and lipoic acid to old rats significantly improves metabolic function while decreasing oxidative stress

Mitochondrial-supported bioenergetics decline and oxidative stress increases during aging. To address whether the dietary addition of acetyl-l-carnitine [ALCAR, 1.5% (wt/vol) in the drinking water] and/or (R)-alpha-lipoic acid [LA, 0.5% (wt/wt) in the chow] improved these endpoints, young (2-4 mo) and old (24-28 mo) F344 rats were supplemented for up to 1 mo before death and hepatocyte isolation. ALCAR+LA partially reversed the age-related decline in average mitochondrial membrane potential and significantly increased (P = 0.02) hepatocellular O(2) consumption, indicating that mitochondrial-supported cellular metabolism was markedly improved by this feeding regimen. ALCAR+LA also increased ambulatory activity in both young and old rats; moreover, the improvement was significantly greater (P = 0.03) in old versus young animals and also greater when compared with old rats fed ALCAR or LA alone. To determine whether ALCAR+LA also affected indices of oxidative stress, ascorbic acid and markers of lipid peroxidation (malondialdehyde) were monitored. The hepatocellular ascorbate level markedly declined with age (P = 0.003) but was restored to the level seen in young rats when ALCAR+LA was given. The level of malondialdehyde, which was significantly higher (P = 0.0001) in old versus young rats, also declined after ALCAR+LA supplementation and was not significantly different from that of young unsupplemented rats. Feeding ALCAR in combination with LA increased metabolism and lowered oxidative stress more than either compound alone.

Effects of minor constituents (non-glyceride compounds) of virgin olive oil on plasma lipid concentrations in male Wistar rats

We aimed to assess the effects of minor constituents (MC) from virgin olive oil upon the plasma lipid profile of experimental animals. Therefore, 32 Wistar rats were fed for 6 weeks with one of four different diets with a similar fatty acid composition but different MC: high-oleic sunflower oil (HOSO), virgin olive oil (VOO), 400%-MC enriched olive oil (EOO) and MC poor (impoverished) olive oil (IOO). At the end of the week 6 of dietary treatment, blood samples were obtained for analysis of lipid composition. A statistically significant influence was observed upon both total HDL (1.593+/-0.4, 1.204+/-0.212, 0.991+/-0.244 and 0.827+/-0.279 mmol/L for EOO, HOSO, VOO and IOO, respectively, Kruskal-Wallis test, P<0.05) and HDL(2)cholesterol levels (1.16+/-0.26, 0.576+/-0.191, 0.585+/-0.216 and 0.583+/-0.207 mmol/L for EOO, HOSO, VOO and IOO, respectively, Kruskal-Wallis test, P<0.05). No statistically significant effect was observed upon LDL-cholesterol or triglycerides. Thus, MC supplementation has beneficial effects on HDL concentrations in Wistar rats.

Mitochondrial bioenergetics in aging

Mitochondria are strongly involved in the production of reactive oxygen species, considered as the pathogenic agent of many diseases and of aging. The mitochondrial theory of aging considers somatic mutations of mitochondrial DNA induced by oxygen radicals as the primary cause of energy decline; experimentally, complex I appears to be mostly affected and to become strongly rate limiting for electron transfer. Mitochondrial bioenergetics is also deranged in human platelets upon aging, as shown by the decreased Pasteur effect (enhancement of lactate production by respiratory chain inhibition). Cells counteract oxidative stress by antioxidants; among lipophilic antioxidants, coenzyme Q is the only one of endogenous biosynthesis. Exogenous coenzyme Q, however, protects cells from oxidative stress by conversion into its reduced antioxidant form by cellular reductases.