Also see:
Protect the Mitochondria
Mitochondrial Medicine
PUFA Accumulation & Aging
“Curing” a High Metabolic Rate with Unsaturated Fats
Fat Deficient Animals – Activity of Cytochrome Oxidase
Dietary PUFA Reflect in Human Subcutaneous Fat Tissue
Toxicity of Stored PUFA
PUFA, Development, and Allergy Incidence
Estrogen Levels Increase with Age
Fat Tissue and Aging – Increased Estrogen
Unsaturated Fats and Age Pigment
Ray Peat, PhD Quotes on Coconut Oil
Medium Chain Fats from Saturated Fat – Weight Management Friendly
Unsaturated Fats and Longevity
Endotoxin: Poisoning from the Inside Out
Ray Peat, PhD on Endotoxin
PUFA Decrease Cellular Energy Production
Fish Oil Toxicity
Protective “Essential Fatty Acid Deficiency”
Glucocorticoids, Cytochrome Oxidase, and Metabolism
Copper: The Forgotten Essential Nutrient
Quotes Ray Peat, PhD:
“A crucial enzyme in the mitochondrion is cytochrome oxidase, which reacts directly with oxygen, completing (or beginning) the process of chemical respiration. It is this enzyme (which is most sensitive to cyanide) which appears to be a “choke point” for energy production in various situations. Learning how to preserve and promote the activity of this enzyme is an important issue for everything having to do with biological energy…Kunkel and Williams (J. Biol. Chem., 1951) found that the very high respiratory rate of animals fed a diet lacking polyunsaturated fats was caused primarily by a great increase in the activity of cytochrome oxidase, and that adding an “essential fatty acid” strongly inhibited this enzyme’s activity.”
“The absorption and retention of magnesium, sodium, and copper, and the synthesis of proteins, are usually poor in hypothyroidism. Salt craving is common in hypothyroidism, and eating additional sodium tends to raise the body temperature, and by decreasing the produc- tion of aldosterone, it helps to minimize the loss of magnesium, which in turn allows cells to respond better to the thyroid hormone. This is probably why a low sodium diet increases adrenalin production, and why eating enough sodium lowers adrenalin and improves sleep. The lowered adrenalin is also likely to improve intestinal motility.”
“Thyroid hormone is essential for forming carbon dioxide. In the early 1940s, experimental rabbits were fed their standard diet, with the addition of 1% desiccated thyroid gland, which would be equivalent to about 150 grains of Armour thyroid for a person. They became extremely hypermetabolic, and couldn’t eat enough to meet their nutritional needs for growth and tissue maintenance. When they died, all of their tissues weighed much less than those of animals that hadn’t received the toxic dose of thyroid, except for their bones, which were larger than normal. Experiments with the thin skull bones of mice have shown that the active thyroid hormone, T3, increases the formation of bone. To increase cellular respiration and carbon dioxide production, T3 increases the activity of the enzyme cytochrome oxidase, which uses copper as a co-factor. Increased thyroid activity increases the absorption of copper from foods.”
“Just a diet can affect it [cytochrome c oxidase], but stress tends to intensify [the loss of] it. Not getting enough light, anything that stresses your energy production system such as high estrogen or nitric oxide, or low thyroid, or too much darkness will tend to make you lose copper from your respiratory system. And as copper gets lost, iron just tends to fill in for it, binding to some of the same enzymes.”
“Iron and copper are best known for their roles in oxygen transport and utilization… Copper is a component or cofactor for mitochondrial cytochrome oxidases, for dopamine B-oxidase (required for the biosynthesis of norepinephrine and epinephrine, of tyrosinase (involved in the biosynthesis of melanin pigments), and lysyl oxidase (which participates in the formation of collage and elastin).”
“I think the issue is just one of propaganda analysis, because scientifically, no one ever refuted the refutation of essentiality which occurred when the “EFA deficiency syndrome” was cured with vitamin B6. The German demonstration that spontaneous cancer was eliminated on a fat free diet preceded the really awful, incompetent study that supposedly demonstrated the essentiality of polyunsaturated fatty acids, and in the 75 years since the German study a tremendous amount of information has accumulated showing both the toxicity and the non-essentiality of the polyunsaturated fatty acids. But there has been no financial support for publicizing the protective effect of not eating vegetable oils or fish oils. To the contrary, vast amounts of money are being spent in the promotion of the various polyunsaturated fats as foods.”
“The animals that don’t eat them do have increased nutritional needs for vitamins and minerals, because their metabolic rate is so much greater than the PUFA-replete animals whose cardiolipin has degenerated. The recent Stanford study that shows a much greater longevity for old people who have a very high oxygen consumption capacity is consistent with the historical animal studies. PUFA-deprived animals have a very high oxygen consumption, and are resistant to practically all causes of death and disease, including trauma and poisoning.”
“The editorial boards of many of the journals are packed with industry flacks who are apparently willing to publish any junk that helps to sell soy oil, canola, waste fish oil, or algae oils. And researchers have to get grants to stay in business.”
“As early as 1951, it was known (Kunkel and Williams, J. BioI. Chern.) that the polyunsaturated fatty acids strongly inhibit the crucial respiratory enzyme, cytochrome oxidase, and that inhibition of this enzyme has a very important effect on the whole animal suppressing its metabolic rate, reducing the number of calories it can burn. It is now known that polyunsaturated fats interfere with thyroid hornone in just about every conceivable way.”
“The mitochondria are responsible for the efficient production of energy needed for the functioning of complex organisms, and especially for nerves. The enzyme in the mitochondria that reacts directly with oxygen, and that is often rate limiting, is cytochrome oxidase.
“This enzyme is dependent upon the thyroid hormone and is inhibited by nitric oxide, carbon monoxide, estrogen, polyunsaturated fatty acids, serotonin, excess or free iron, ionizing radiation, and many toxins, including bacterial endotoxin. Red light, which passes easily through the tissues, reactivates the enzyme, which slowly loses its function during darkness.”
“Estrogen impairs the mitochondria in multiple ways, including blocking the function of cytochrome oxidase, decreasing the activity of ATP synthase, increasing heme oxygenase which produces carbon monoxide and free iron, damaging mitochondrial DNA, and shifting metabolism from glucose oxidation to fat oxidation, especially by inhibiting pyruvate dehyrogenase complex. These changes including the loss of cytochrome oxidase, are seen in the Alzheimer’s brain. The fact that this kind of energy impairment can be produced by estrogen doesn’t imply that estrogen is the cause, since many other things can cause similar effects–radiation, aluminum, endotoxin, for example.”
“The choice of foods which have less unsaturated fat tends to reinforce the achievements of evolution.”
“The fetus produces saturated fats such as palmitic acid, and the monounsaturated fat, oleic acid, which can be turned into the Mead acid, ETrA (5,8,11-eicosatrienoic acid), and its derivatives, which are antiinflammatory, and some of which act on the “bliss receptor,” or the cannibinoid receptor.
“At birth, the baby’s mitochondria contain a phospholipid, cardiolipin, containing palmitic acid, but as the baby eats foods containing polyunsaturated fatty acids, the palmitic acid in cardiolipin is replaced by the unsaturated fats. As the cardiolipin becomes more unsaturated, it becomes less stable, and less able to support the activity of the crucial respiratory enzyme, cytochrome oxidase.”
“The respiratory activity of the mitochondria declines as the polyunsaturated oils replace palmitic acid, and this change corresponds to the life-long decline of the person’s metabolic rate.”
“Cytochrome oxidase is one of the enzymes damaged by stress and by blue light, and activated or restored by red light, thyroid, and progesterone. It’s a copper enzyme, so it’s likely to be damaged by excess iron. It is most active when it is associated with a mitochondrial lipid, cardiolipin, that contains saturated palmitic acid; the substitution of polyunsaturated fats lowers its activity. Mitochonrial function in general is poisoned by the unsaturated fats, especially arachidonic acid and DHA.”
“The suppressive effects of unsaturated fats on mitochondrial energy production have been widely investigated, since it is that effect that makes animal fattening with PUFA so economical. Rather than interpreting that as a toxic effect, using the innate structure and function of the mitochondrion as a point of reference from which to evaluate dietary components, the consumption of “good” oils is being used as the reference point from which to evaluate the meaning of metabolism (“efficiency is good,” “low oxygen consumption is good”). Building on the idea that the oils are health-promoters which increase metabolic efficiency, the never-viable “rate of aging” theory was resuscitated: The anti-respiratory effect of PUFA is used (illogically) to return to the idea that aging occurs in proportion to the amount of oxygen consumed, because animals which lack the supposedly essential nutrients (“defective animals”) consume oxygen rapidly–burning calories rapidly, they are supposed to be like a candle that won’t last as long if it burns intensely. The old theory is simply resuscitated to explain why the anti-respiratory action of PUFA might be beneficial, justifying further promotion of their use as food and drugs.”
“When mitochondria are functioning fully, either glucose or saturated fats can safely provide energy. Some glucose or saturated fat can be converted to polyunsaturated fats, that can be used as regulators or signals, for example to activate the formation of stem cells. But those PUFA don’t create disruptive cascades of increasing excitation or inflammation or excessive growth, and, from the evidence of animals that are fed fat free diets, or diets lacking omega -3 and omega -6 fatty acids, they aren’t toxic to mitochondria.”
“Increased estrogen exposure, decreased thyroid hormone, an increased ratio of iron to copper, and lack of light, are other factors that impair the cytochrome oxidase enzyme.”
“The crucial mitochondrial respiratory enzyme, cytochrome c oxidase, declines with aging (Paradies, et al., 1997), as the lipid cardiolipin declines, and the enzyme’s activity can be restored to the level of young animals by adding cardiolipin. The composition of cardiolipin changes with aging, “specifically an increase in highly unsaturated fatty acids” (Lee, et al., 2006). Other lipids, such as a phosphatidylcholine containing two myristic acid groups, can support the enzyme’s activity (Hoch, 1992). Even supplementing old animals with hydrogenated peanut oil restores mitochondrial respiration to about 80% of normal (Bronnikov, et al., 2010).”
“Supplementing thyroid hormone increases mitochondrial cardiolipin (Paradies and Ruggiero, 1988). Eliminating the polyunsaturated fats from the diet increases mitochondrial respiration (Rafael, et al., 1984).”
“On a typical diet, tissues progressively accumulate linoleic acid, and this alters the structure of mitochondrial cardiolipin, which governs the response of the mitochondrial enzymes to the thyroid hormone. This process is especially evident in the female liver. In the “autoimmune” diseases, such as lupus, there are typically antibodies to cardiolipin, as if the body were trying to reject its own tissues, which have been altered by the storage of linoleic acid.
The altered mitochondrial function, which is involved in so many symptoms, can become part of a vicious circle, with endotoxin and estrogen having central roles, once the stage has been set by the combination of diet, stress, and toxins.”
J Biol Chem. 1951 Apr;189(2):755-61.
The effects of fat deficiency upon enzyme activity in the rat.
KUNKEL HO, WILLIAMS JN Jr.
The activity of the cytochrome oxidase, however, is markedly increased in fat deficiency…In each case the activity of livers from rats fed the basal diet was 38 per cent greater than from the linoleate-supplemented animals or from the animals receiving corn oil. This is particularly interesting in view of the observation of Burr and Beeber (8) and Wesson and Burr (9) that fat-deficient rats had a markedly increased metabolic rate. The latter authors reported that the basal and assimilatory metabolic rates of fat-deficient animals were 25 per cent greater than the rates of the control animals. Thus the liver cytochrome oxidase activity appears to parallel the met,abolic rate in fat deficiency. This increased cytochrome oxidase activity in liver and perhaps other tissues may account in a large part for the increased metabolic rate.
Summary
A fat deficiency in the rat causes a marked increase in liver cytochrome oxidase activity, a slight increase in choline oxidase activity, and a marked decrease in endogenous respiration. The activity of the succinic oxidase system is not altered by this deficiency condition. Supplementation with 100 mg. of methyl linoleate per rat per day reduced the cytochrome oxidase to the level of that produced by a 5 percent corn oil diet.
FEBS Lett. 1997 Apr 7;406(1-2):136-8.
Age-dependent decline in the cytochrome c oxidase activity in rat heart mitochondria: role of cardiolipin.
Paradies G, Ruggiero FM, Petrosillo G, Quagliariello E.
Cardiolipin is a major mitochondrial membrane lipid and plays a pivotal role in mitochondrial function. We have recently suggested a possible involvement of this phospholipid in the age-linked decline of cytochrome c oxidase activity in rat heart mitochondria [G. Paradies et al. (1993) Arch. Gerontol. Geriatr. 16, 263-272]. The aim of this work was to test our earlier proposal. We have investigated whether addition of exogenous cardiolipin to mitochondria is able to reverse, in situ, the age-linked decrease in the cytochrome oxidase activity. The method of fusion of liposomes with mitochondria developed by Hackenbrock [Hackenbrock and Chazotte (1986) Methods Enzymol. 125, 35-45] was employed in order to enrich the mitochondria cardiolipin content. We demonstrate that the lower cytochrome c oxidase activity in heart mitochondria from aged rats can be fully restored to the level of young control rats by exogenously added cardiolipin. No restoration was obtained with other phospholipids or with peroxidized cardiolipin. Our data support a key role for cardiolipin in the age-linked decline of rat heart mitochondrial cytochrome c oxidase activity.
FEBS Lett. 1999 Jul 9;454(3):207-9.
The effect of aging and acetyl-L-carnitine on the pyruvate transport and oxidation in rat heart mitochondria.
Paradies G, Petrosillo G, Gadaleta MN, Ruggiero FM.
The effect of aging and acute treatment with acetyl-L-carnitine on the pyruvate transport and oxidation in rat heart mitochondria was studied. The activity of the pyruvate carrier as well as the rates of pyruvate-supported respiration were both depressed (around 40%) in heart mitochondria from aged rats, the major decrease occurring during the second year of life. Administration of acetyl-L-carnitine to aged rats almost completely restored the rates of these metabolic functions to the level of young control rats. This effect of acetyl-L-carnitine was not due to changes in the content of pyruvate carrier molecules. The heart mitochondrial content of cardiolipin, a key phospholipid necessary for mitochondrial substrate transport, was markedly reduced (approximately 40%) in aged rats. Treatment of aged rats with acetyl-L-carnitine reversed the age-associated decline in cardiolipin content. As the changes in cardiolipin content were correlated with changes in rates of pyruvate transport and oxidation, it is suggested that acetyl-L-carnitine reverses the age-related decrement in the mitochondrial pyruvate metabolism by restoring the normal cardiolipin content.
Lipids Health Dis. 2006 Jan 23;5:2.
Selective remodeling of cardiolipin fatty acids in the aged rat heart.
Lee HJ, Mayette J, Rapoport SI, Bazinet RP.
BACKGROUND:
The heart is rich in cardiolipin, a phospholipid acylated in four sites, predominately with linoleic acid. Whether or not aging alters the composition of cardiolipin acyl chains is controversial. We therefore measured the fatty acid concentration of cardiolipin in hearts of 4, 12 and 24 month old rats that consumed one diet, adequate in fatty acids for the duration of their life.
RESULTS:
The concentration (nmol/g) of linoleic acid was decreased in 24 month old rats (3965 +/- 617, mean +/- SD) vs 4 month old rats (5525 +/- 656), while the concentrations of arachidonic and docosahexaenoic acid were increased in 24 month old rats (79 +/- 9 vs 178 +/- 27 and 104 +/- 16 vs 307 +/- 68 for arachidonic and docosahexaenoic acids, 4 months vs 24 months, respectively). Similar changes were not observed in ethanolamine glycerophospholipids or plasma unesterified fatty acids, suggesting specificity of these effects to cardiolipin.
CONCLUSION:
These results demonstrate that cardiolipin remodeling occurs with aging, specifically an increase in highly unsaturated fatty acids.
Biochemistry (Mosc). 2010 Dec;75(12):1491-7.
Dietary supplementation of old rats with hydrogenated peanut oil restores activities of mitochondrial respiratory complexes in skeletal muscles.
Bronnikov GE, Kulagina TP, Aripovsky AV.
The effect of dietary supplementation of old rats (26-33 months) with hydrogenated peanut oil on the activity of mitochondrial enzymes in skeletal muscles has been studied. The activities of NADH-coenzyme Q1 oxidoreductase, cytochrome c oxidase, and citrate synthase were determined spectrophotometrically in muscle homogenates. The activities of respiratory complexes I and IV were shown to significantly decrease with the age compared to the activity of the same enzymes in young animals, while the activity of citrate synthase was virtually unchanged. The fatty acid composition of muscle homogenates of old rats differed from that of young animals by a reduced content of myristic, oleic, linoleic, and α-linolenic acids and enhanced content of dihomo-γ-linolenic, arachidonic, and docosahexaenoic acids. Per oral supplementation of the old rats with hydrogenated peanut oil completely restored the activity of complex IV and increased the activity of complex I to 80% of the value observed in muscles of young animals, reducing the content of stearic, dihomo-γ-linolenic, arachidonic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids relative to that in the groups of old and young rats. The content of oleic and linoleic acids increased relatively to that in the group of the old rats, as well as young animals. The possible mechanisms of the restoration of the activity of the respiratory enzymes under the administration of hydrogenated peanut oil are discussed.
Biochim Biophys Acta. 1988 Aug 17;935(1):79-86.
Effect of hyperthyroidism on the transport of pyruvate in rat-heart mitochondria.
Paradies G, Ruggiero FM.
A comparative study of the transport of pyruvate in heart mitochondria from normal and triiodothyronine-treated rats has been carried out. It has been found that the rate of carrier-mediated (alpha-cyanocinnamate-sensitive) pyruvate uptake is significantly enhanced in mitochondria from triiodothyronine-treated rats as compared with mitochondria from control rats. The kinetic parameters of the pyruvate uptake indicate that only the Vmax of this process is enhanced whilst there is no change in the Km value. The enhanced rate of pyruvate uptake is not dependent on the increase of the transmembrane delta pH value (both mitochondria from normal and triiodothyronine-treated rats exhibit the same delta pH value) neither does it depend on the increase of the pyruvate carrier molecules (titration of these last with alpha-cyanocinnamate gives the same total number of binding sites). the pyruvate-dependent oxygen uptake is stimulated by 35-40% in mitochondria from hyperthyroid rats when compared with mitochondria from control rats. There is, however, no difference in either the respiratory control ratios or in the ADP/O ratios between these two types of mitochondria. The heart mitochondrial phospholipid composition is altered significantly in hyperthyroid rats; in particular, negatively charged phospholipid such as cardiolipin and phosphatidylserine were found to increase by more than 50%. Minor alterations were found in the pattern of fatty acids with an increase of 20:4/18:2 ratio. It is suggested that the changes in the kinetic parameters of pyruvate transport in mitochondria from hyperthyroid rats involve hormone-mediated changes in the lipid composition of the mitochondrial membranes which in turn modulate the activity of the pyruvate carrier.
J Nutr. 1984 Feb;114(2):255-62.
The effect of essential fatty acid deficiency on basal respiration and function of liver mitochondria in rats.
Rafael J, Patzelt J, Schäfer H, Elmadfa I.
Rats were fed a diet poor (0.05%) in essential fatty acids (EFA) with hydrogenated coconut oil as fat component, or a control diet containing 4% of the total energy intake in the form of linoleic acid. Effects of dietary EFA deficiency were investigated during a period of 2-30 weeks. Growth retardation becomes significant after 4 weeks of deficiency and attains about 25% when the deficiency is maintained for longer than 12 weeks. Respiration, body weight and age of EFA-deficient rats and controls are in a nonlinear relationship. Basal respiration in relation to the body weight is significantly increased by EFA deficiency; it is unchanged when related to total animals under the employed experimental conditions. Oxidative phosphorylation in isolated liver mitochondria is unaffected by EFA deficiency, i.e., the increased metabolic rate of EFA-deficient rats, related to the body weight, cannot be explained from impaired functional integrity of the inner mitochondrial membrane. Respiratory chain enzyme activities in mitochondria from heart and skeletal muscle and specific amounts of mitochondria in these tissues are unchanged by EFA deficiency.
Arch Gerontol Geriatr. 1993 May-Jun;16(3):263-72.
Age-dependent decrease in the cytochrome c oxidase activity and changes in phospholipids in rat-heart mitochondria.
Paradies G, Ruggiero FM, Petrosillo G, Quagliariello E.
The effect of aging on the kinetic characteristics of cytochrome c oxidase in rat heart mitochondria was investigated. Mitochondria from young and aged rats had equivalent Km values for cytochrome c, while the maximal activity of the oxidase was significantly reduced in mitochondria from aged rats. The cytochrome aa3 content was the same in both these two types of mitochondria. The Arrhenius plot characteristics differ for cytochrome oxidase activity in mitochondria from aged rats as compared with young rats in that the breakpoint of the biphasic plot was shifted to a higher temperature. Cardiolipin content was markedly decreased in mitochondrial membrane from aged rats. No alterations were found in the patterns of the phospholipid fatty acid distribution of mitochondrial membranes from young and aged rats. The results support the conclusion that the reduced mitochondrial cytochrome c oxidase activity in aged animals is due to a specific decrease in the cardiolipin content.
Biochim Biophys Acta. 1995 May 24;1271(1):165-70.
Mitochondrial decay in aging.
Ames BN, Shigenaga MK, Hagen TM.
Several mitochondrial functions decline with age. The contributing factors include, the intrinsic rate of proton leakage across the inner mitochondrial membrane (a correlate of oxidant formation), decreased membrane fluidity, and decreased levels and function of cardiolipin, which supports the function of many of the proteins of the inner mitochondrial membrane. Oxidants generated by mitochondria appear to be the major source of the oxidative lesions that accumulate with age. Evidence supports the suggestion that age-associated accumulation of mitochondrial deficits due to oxidative damage is likely to be a major contributor to cellular, tissue, and organismal aging.
“With aging, cells have less ability to produce energy, and are often more easily stimulated. The accumulation of polyunsaturated fats is one of the factors that reduce the ability of mitochondria to produce energy (Zhang, et al., 2006, 2009; Yazbeck, et al., 1989). Increased estrogen exposure, decreased thyroid hormone, an increased ratio of iron to copper, and lack of light, are other factors that impair the cytochrome oxidase enzyme.” -Ray Peat, PhD
Comp Biochem Physiol A Comp Physiol. 1989;94(2):273-6.
The effects of essential fatty acid deficiency on brown adipose tissue activity in rats maintained at thermal neutrality.
Yazbeck J, Goubern M, Senault C, Chapey MF, Portet R.
1. The consequences of essential fatty acid (EFA) deficiency on the resting metabolism, food efficiency and brown adipose tissue (BAT) thermogenic activity were examined in rats maintained at thermal neutrality (28 C). 2. Weanling male Long-Evans rats were fed a hypolipidic semi-purified diet (control diet: 2% sunflower oil; EFA-deficient diet: 2% hydrogenated coconut oil) for 9 weeks. 3. They were kept at 28 C for the last 5 weeks. Compared to controls, in EFA-deficient rats the growth shortfall reached 21% at killing. 4. As food intake was the same in EFA-deficient and control rats, food efficiency was thus decreased by 40%. 5. Resting metabolism expressed per surface unit was 15% increased. 6. Non-renal water loss was increased by 88%. 7. BAT weight was 28% decreased but total and mitochondrial proteins were not modified. 8. Heat production capacity, tested by GDP binding per BAT was 69% increased in BAT of deficient rats. 9. The stimulation of BAT was established by two other tests: GDP inhibition of mitochondrial O2 consumption and swelling of mitochondria. 10. It is suggested that the observed enhancement of resting metabolism in EFA-deficient rats is, in part, due to an activation of heat production in BAT.
Am J Physiol Cell Physiol. 2006 May;290(5):C1321-33.
Polyunsaturated fatty acids mobilize intracellular Ca2+ in NT2 human teratocarcinoma cells by causing release of Ca2+ from mitochondria.
Zhang BX, Ma X, Zhang W, Yeh CK, Lin A, Luo J, Sprague EA, Swerdlow RH, Katz MS.
In a variety of disorders, overaccumulation of lipid in nonadipose tissues, including the heart, skeletal muscle, kidney, and liver, is associated with deterioration of normal organ function, and is accompanied by excessive plasma and cellular levels of free fatty acids (FA). Increased concentrations of FA may lead to defects in mitochondrial function found in diverse diseases. One of the most important regulators of mitochondrial function is mitochondrial Ca(2+) ([Ca(2+)](m)), which fluctuates in coordination with intracellular Ca(2+) ([Ca(2+)](i)). Polyunsaturated FA (PUFA) have been shown to cause [Ca(2+)](i) mobilization albeit by unknown mechanisms. We have found that PUFA but not monounsaturated or saturated FA cause [Ca(2+)](i) mobilization in NT2 human teratocarcinoma cells. Unlike the [Ca(2+)](i) response to the muscarinic G protein-coupled receptor agonist carbachol, PUFA-mediated [Ca(2+)](i) mobilization in NT2 cells is independent of phospholipase C and inositol-1,4,5-trisphospate (IP(3)) receptor activation, as well as IP(3)-sensitive internal Ca(2+) stores. Furthermore, PUFA-mediated [Ca(2+)](i) mobilization is inhibited by the mitochondria uncoupler carboxyl cyanide m-chlorophenylhydrozone. Direct measurements of [Ca(2+)](m) with X-rhod-1 and (45)Ca(2+) indicate that PUFA induce Ca(2+) efflux from mitochondria. Further studies show that ruthenium red, an inhibitor of the mitochondrial Ca(2+) uniporter, blocks PUFA-induced Ca(2+) efflux from mitochondria, whereas inhibitors of the mitochondrial permeability transition pore cyclosporin A and bongkrekic acid have no effect. Thus PUFA-gated Ca(2+) release from mitochondria, possibly via the Ca(2+) uniporter, appears to be the underlying mechanism for PUFA-induced [Ca(2+)](i) mobilization in NT2 cells.
PLoS ONE 4(6): e6048. doi:10.1371/journal.pone.0006048
Linoleic Acid-Induced Mitochondrial Ca2+ Efflux Causes Peroxynitrite Generation and Protein Nitrotyrosylation
Hong-Mei Zhang1, Howard Dang2, Chih-Ko Yeh3,4, Bin-Xian Zhang1,4*
It is well known that excessive non-esterified fatty acids in diabetes contribute to the pathogenesis of renal complications although the mechanism remains elusive. Enhanced oxidative stress has been hypothesized as a unified factor contributing to diabetic complications and increased protein nitrotyrosylation has been reported in the kidneys of diabetic patients. In the current manuscript we described that linoleic acid (LA) caused mitochondrial Ca2+ efflux and peroxynitrite production, along with increased nitrotyrosine levels of cellular proteins in primary human mesangial cells. The peroxynitrite production by LA was found to depend on mitochondrial Ca2+ efflux. Downregulation of hsp90β1, which has been previously shown to be essential for polyunsaturated fatty acid-induced mitochondrial Ca2+ efflux, significantly diminished LA-responsive mitochondrial Ca2+ efflux and the coupled peroxynitrite generation, implicating a critical role of hsp90β1 in the LA responses. Our results further demonstrated that mitochondrial complexes I and III were directly involved in the LA-induced peroxynitrite generation. Using the well established type 2 diabetic animal model db/db mice, we observed a dramatically enhanced LA responsive mitochondrial Ca2+ efflux and protein nitrotyrosylation in the kidney. Our study thus demonstrates a cause-effect relationship between LA and peroxynitrite or protein nitrotyrosylation and provides a novel mechanism for lipid-induced nephropathy in diabetes.
Endocrine. 2011 Apr;39(2):128-38. Epub 2010 Dec 15.
Long-term exposure of INS-1 rat insulinoma cells to linoleic acid and glucose in vitro affects cell viability and function through mitochondrial-mediated pathways.
Tuo Y, Wang D, Li S, Chen C.
Obesity with excessive levels of circulating free fatty acids (FFAs) is tightly linked to the incidence of type 2 diabetes. Insulin resistance of peripheral tissues and pancreatic β-cell dysfunction are two major pathological changes in diabetes and both are facilitated by excessive levels of FFAs and/or glucose. To gain insight into the mitochondrial-mediated mechanisms by which long-term exposure of INS-1 cells to excess FFAs causes β-cell dysfunction, the effects of the unsaturated FFA linoleic acid (C 18:2, n-6) on rat insulinoma INS-1 β cells was investigated. INS-1 cells were incubated with 0, 50, 250 or 500 μM linoleic acid/0.5% (w/v) BSA for 48 h under culture conditions of normal (11.1 mM) or high (25 mM) glucose in serum-free RPMI-1640 medium. Cell viability, apoptosis, glucose-stimulated insulin secretion, Bcl-2, and Bax gene expression levels, mitochondrial membrane potential and cytochrome c release were examined. Linoleic acid 500 μM significantly suppressed cell viability and induced apoptosis when administered in 11.1 and 25 mM glucose culture medium. Compared with control, linoleic acid 500 μM significantly increased Bax expression in 25 mM glucose culture medium but not in 11.1 mM glucose culture medium. Linoleic acid also dose-dependently reduced mitochondrial membrane potential (ΔΨm) and significantly promoted cytochrome c release from mitochondria in both 11.1 mM glucose and 25 mM glucose culture medium, further reducing glucose-stimulated insulin secretion, which is dependent on normal mitochondrial function. With the increase in glucose levels in culture medium, INS-1 β-cell insulin secretion function was deteriorated further. The results of this study indicate that chronic exposure to linoleic acid-induced β-cell dysfunction and apoptosis, which involved a mitochondrial-mediated signal pathway, and increased glucose levels enhanced linoleic acid-induced β-cell dysfunction.
FEBS Lett. 1996 Nov 18;397(2-3):260-2.
Stimulation of carnitine acylcarnitine translocase activity in heart mitochondria from hyperthyroid rats.
Paradies G, Ruggiero FM, Petrosillo G, Quagliariello E.
The effect of hyperthyroidism on fatty acid oxidation and on carnitine-acylcarnitine translocase activity in rat heart mitochondria has been studied. The rates of palmitoylcarnitine supported respiration as well as the carnitine-palmitoylcarnitine exchange reaction were both stimulated (approx. 36%) in heart mitochondria from hyperthyroid rats. Kinetic analysis of the carnitine-carnitine exchange reaction showed that thyroid hormone affects the Vmax of this process, while having no effect on the Km values. The level of cardiolipin was significantly higher (approx. 40%) in heart mitoplasts from hyperthyroid rats than from the control rats. It can be concluded that thyroid hormones produce a stimulation of heart mitochondrial carnitine translocase activity and that the basis of this effect is likely an increase in the cardiolipin content.
FEBS Lett. 1998 Mar 13;424(3):155-8.
Peroxidative damage to cardiac mitochondria: cytochrome oxidase and cardiolipin alterations.
Paradies G, Ruggiero FM, Petrosillo G, Quagliariello E.
Rat heart mitochondrial membranes exposed to the free radicals generating system tert-butylhydroperoxide/Cu2+ undergo lipid peroxidation as evidenced by the accumulation of thyobarbituric acid reactive substances. Mitochondrial lipid peroxidation resulted in a marked loss of both cytochrome c oxidase activity and cardiolipin content. The alterations in the properties of cytochrome c oxidase were confined to a decrease in the maximal activity (Vmax) with no change in the affinity (Km) with respect to the substrate cytochrome c. Various lipid soluble antioxidants could prevent the lipid peroxidation reaction and the associated loss of cytochrome c oxidase activity. External added cardiolipin but no other phospholipids, nor peroxidized cardiolipin was able to prevent the loss of cytochrome oxidase activity induced by lipid peroxidation. These results establish a close correlation between oxidative damage to cardiolipin and alterations in the cytochrome oxidase activity and may prove useful in probing molecular mechanism of free radicals induced peroxidative damage of mitochondria which has been proposed to contribute to aging and to chronic degenerative diseases.
Biochim Biophys Acta. 1994 Jan 11;1225(2):165-70.
Enhanced cytochrome oxidase activity and modification of lipids in heart mitochondria from hyperthyroid rats.
Paradies G, Ruggiero FM, Petrosillo G, Quagliariello E.
In order to further investigate the mechanism regulating the control of mitochondrial respiration by thyroid hormones, the effect of the hyperthyroidism on the kinetic characteristics of cytochrome c oxidase in rat heart mitochondria was studied. Mitochondrial preparations from both control and hyperthyroid rats had equivalent Km values for cytochrome c, while the maximal activity of cytochrome oxidase was significantly increased (by around 30%) in mitochondrial preparation from hyperthyroid rats. This enhanced activity of cytochrome oxidase was associated to a parallel increase in mitochondrial State 3 respiration. The hormone treatment resulted in a decrease in the flux control coefficient of the oxidase. The enhanced activity of cytochrome oxidase in hyperthyroid rats does not appear to be dependent on an increase in the mass of this enzyme complex in that the heme aa3 content was equivalent in both hyperthyroid and control preparations. The Arrhenius plot characteristics differ for cytochrome oxidase activity in mitochondria from hyperthyroid rats as compared with control rats in that the breakpoint of the biphasic plot is shifted to a lower temperature. Cardiolipin content was significantly increased in mitochondrial preparations from hyperthyroid rats, while there were no significant alterations in the fatty acid composition of cardiolipin of control and hyperthyroid preparations. The results support the conclusion that the enhanced cytochrome oxidase activity in heart mitochondrial preparations from hyperthyroid rats is due to a specific increase in the content of cardiolipin.
Biochim Biophys Acta. 1997 Dec 31;1362(2-3):193-200.
Alterations in carnitine-acylcarnitine translocase activity and in phospholipid composition in heart mitochondria from hypothyroid rats.
Paradies G, Ruggiero FM, Petrosillo G, Quagliariello E.
Changes in mitochondrial fatty acid metabolism may underlie the decline in cardiac function in the hypothyroid animals. The effect of hypothyroidism on fatty acid oxidation, carnitine-acylcarnitine translocase activity and lipid composition in rat heart mitochondria has been examined. Rates of mitochondrial fatty acid oxidation as well as carnitine-carnitine and carnitine-palmitoylcarnitine exchange reactions were all depressed in heart mitochondria isolated from hypothyroid rats. Kinetic analysis of the carnitine-carnitine exchange reaction showed that the hypothyroid state affects the Vmax of this process, while having no effect on the K(m) value. Heart mitochondrial inner membrane lipid composition was significantly altered in hypothyroid rats. Cardiolipin, particularly, was found to decrease (by around 36%). Alterations in fatty acid pattern of mitochondrial inner membrane preparations from hypothyroid rats were also found. The effects of the hypothyroid state on fatty acids oxidation, carnitine translocase activity and phospholipid composition were completely reversed by following treatment of hypothyroid rats with thyroid hormone. A lower cardiolipin content in the mitochondrial inner membrane offers a plausible mechanism to explain the decline in the translocase activity in hypothyroidism.
Arch Biochem Biophys. 1993 Nov 15;307(1):91-5.
Decreased cytochrome oxidase activity and changes in phospholipids in heart mitochondria from hypothyroid rats.
Paradies G, Ruggiero FM, Dinoi P, Petrosillo G, Quagliariello E.
The effect of hypothyroidism on kinetic characteristics of cytochrome oxidase in rat heart mitochondria was studied. Mitochondrial preparations from control and hypothyroid rats had equivalent Km values for cytochrome c, while the maximal activity of the oxidase was significantly decreased (more than 30%) in mitochondrial preparations from hypothyroid rats. This decrease is associated to a parallel decrease in state 3 respiration. The cytochrome aa3 content was slightly decreased (by around 15%) in mitochondria from hypothyroid rats. The Arrhenius plot characteristics differ for cytochrome oxidase activity in mitochondria from hypothyroid rats as compared with control rats in that the breakpoint of the biphasic plot is shifted to a higher temperature. Cardiolipin content was markedly decreased in the mitochondrial membrane from hypothyroid rats. No alterations were found in the pattern of cardiolipin fatty acid distribution of mitochondrial membrane from control and hypothyroid rats. The effects of the hypothyroid state on the activity of cytochrome oxidase, on cytochrome aa3 levels, and on cardiolipin contents were completely reversed by following the treatment of hypothyroid rats with thyroid hormone. The results support the conclusion that the depressed mitochondrial cytochrome oxidase activity in the hypothyroid state is due, at least in part, to a decrease in the cardiolipin content of the mitochondrial inner membrane.
Biochim Biophys Acta. 1997 Mar 28;1319(1):5-8.
Cardiolipin-dependent decrease of cytochrome c oxidase activity in heart mitochondria from hypothyroid rats.
Paradies G, Petrosillo G, Ruggiero FM.
Cardiolipin plays an important role in mitochondrial membrane structure and function. We have recently reported a decrease in the cytochrome c oxidase activity in heart mitochondria from hypothyroid rats (G. Paradies et al. (1993) Arch. Biochem Biophys. 307, 91-95). A possible involvement of cardiolipin in such a decrease has been proposed. The aim of this work was to test our earlier proposal. We have investigated whether addition of exogenous cardiolipin to hypothyroid mitochondria is able to reverse, in situ, their decreased cytochrome oxidase activity. The method of fusion of liposomes with mitochondria developed by Hackenbrock (Hackenbrock and Chazotte (1986) Methods Enzymol. 125, 35-45) was employed in order to enrich the mitochondrial cardiolipin content. We demonstrate that the decreased activity of this enzyme complex in heart mitochondria from hypothyroid rats can be completely restored to the level of control rats by exogenously added cardiolipin but not by other phospholipids. These data provide strong evidence for the involvement of cardiolipin in the thyroid hormone induced changes of mitochondrial cytochrome oxidase activity.
Mitochondrion. 2001 Aug;1(2):151-9.
Reactive oxygen species generated by the mitochondrial respiratory chain affect the complex III activity via cardiolipin peroxidation in beef-heart submitochondrial particles.
Paradies G, Petrosillo G, Pistolese M, Ruggiero FM.
The aim of this study was to investigate the effect of reactive oxygen species (ROS), produced by the mitochondrial respiratory chain, on the activity of complex III and on the cardiolipin content in bovine-heart submitochondrial particles (SMP). ROS were produced by treatment of nicotinamide adenine dinucleotide (NADH) respiring SMP with rotenone. This treatment resulted in a production of superoxide anion, detected by the epinephrine method, which was blocked by superoxide dismutase (SOD). Exposure of SMP to mitochondrial-mediated ROS generation resulted in a marked loss of complex III activity and in a parallel loss of mitochondrial cardiolipin content. Both these effects were completely abolished by SOD + catalase. Exogenous added cardiolipin was able to almost completely prevent the ROS-mediated loss of complex III activity. No effect was obtained with other major phospholipid components of the mitochondrial membrane such as phosphatidylcholine and phosphatidylethanolamine, or with peroxidized cardiolipin. The results demonstrate that mitochondrial-mediated ROS generation affects the activity of complex III via peroxidation of cardiolipin, which is required for the functioning of this multisubunit enzyme complex. These results may prove useful in probing molecular mechanisms of ROS-induced peroxidative damage to mitochondria, which have been proposed to contribute to those physiopathological conditions characterized by an increase in the basal production of ROS such as aging, ischemia/reperfusion and chronic degenerative diseases.
Free Radic Biol Med. 1999 Jul;27(1-2):42-50.
Lipid peroxidation and alterations to oxidative metabolism in mitochondria isolated from rat heart subjected to ischemia and reperfusion.
Paradies G, Petrosillo G, Pistolese M, Di Venosa N, Serena D, Ruggiero FM.
Ischemia-reperfusion injury to cardiac myocytes involves membrane damage mediated by oxygen free radicals. Lipid peroxidation is considered a major mechanism of oxygen free radical toxicity in reperfused heart. Mitochondrial respiration is an important source of these reactive oxygen species and hence a potential contributor to reperfusion injury. We have examined the effects of ischemia (30 min) and ischemia followed by reperfusion (15 min) of rat hearts, on the kinetic parameters of cytochrome c oxidase, on the respiratory activities and on the phospholipid composition in isolated mitochondria. Mitochondrial content of malonyldialdheyde (MDA), an index of lipid peroxidation, was also measured. Reperfusion was accompanied by a significant increase in MDA production. Mitochondrial preparations from control, ischemic and reperfused rat heart had equivalent Km values for cytochrome c, although the maximal activity of the oxidase was 25 and 51% less in ischemic and reperfused mitochondria than that of controls. These changes in the cytochrome c oxidase activity were associated to parallel changes in state 3 mitochondrial respiration. The cytochrome aa3 content was practically the same in these three types of mitochondria. Alterations were found in the mitochondrial content of the major phospholipid classes, the most pronounced change occurring in the cardiolipin, the level that decreased by 28 and by 50% as function of ischemia and reperfusion, respectively. The lower cytochrome c oxidase activity in mitochondria from reperfused rat hearts could be almost completely restored to the level of control hearts by exogenously added cardiolipin, but not by other phospholipids nor by peroxidized cardiolipin. It is proposed that the reperfusion-induced decline in the mitochondrial cytochrome c oxidase activity can be ascribed, at least in part, to a loss of cardiolipin content, due to peroxidative attack of its unsaturated fatty acids by oxygen free radicals. These findings may provide an explanation for some of the factors that lead to myocardial reperfusion injury.
Gene. 2002 Mar 6;286(1):135-41.
Reactive oxygen species affect mitochondrial electron transport complex I activity through oxidative cardiolipin damage.
Paradies G, Petrosillo G, Pistolese M, Ruggiero FM.
The aim of this study was to investigate the influence of reactive oxygen species (ROS) on the activity of complex I and on the cardiolipin content in bovine heart submitochondrial particles (SMP). ROS were generated through the use of xanthine/xanthine oxidase (X/XO) system. Treatment of SMP with X/XO resulted in a large production of superoxide anion, detected by acetylated cytochrome c method, which was blocked by superoxide dismutase (SOD). Exposure of SMP to ROS generation resulted in a marked loss of complex I activity and to parallel loss of mitochondrial cardiolipin content. Both these effects were completely abolished by SOD+catalase. Exogenous added cardiolipin was able to almost completely restore the ROS-induced loss of complex I activity. No restoration was obtained with other major phospholipid components of the mitochondrial membrane such as phosphatidylcholine and phosphatidylethanolamine, nor with peroxidized cardiolipin. These results demonstrate that ROS affect the mitochondrial complex I activity via oxidative damage of cardiolipin which is required for the functioning of this multisubunit enzyme complex. These results may prove useful in probing molecular mechanisms of ROS-induced peroxidative damage to mitochondria, which have been proposed to contribute to those pathophysiological conditions characterized by an increase in the basal production of reactive oxygen species such as aging, ischemia/reperfusion and chronic degenerative diseases.
FEBS Lett. 2000 Jan 28;466(2-3):323-6.
The effect of reactive oxygen species generated from the mitochondrial electron transport chain on the cytochrome c oxidase activity and on the cardiolipin content in bovine heart submitochondrial particles.
Paradies G, Petrosillo G, Pistolese M, Ruggiero FM.
The effect of reactive oxygen species (ROS), produced by the mitochondrial respiratory chain, on the activity of cytochrome c oxidase and on the cardiolipin content in bovine heart submitochondrial particles (SMP) was studied. ROS were produced by treatment of succinate-respiring SMP with antimycin A. This treatment resulted in a large production of superoxide anion, measured by epinephrine method, which was blocked by superoxide dismutase (SOD). Exposure of SMP to mitochondrial mediated ROS generation, led to a marked loss of cytochrome c oxidase activity and to a parallel loss of cardiolipin content. Both these effects were completely abolished by SOD+catalase. Added cardiolipin was able to almost completely restore the ROS-induced loss of cytochrome c oxidase activity. No restoration was obtained with peroxidized cardiolipin. These results demonstrate that mitochondrial mediated ROS generation affects the activity of cytochrome c oxidase via peroxidation of cardiolipin which is needed for the optimal functioning of this enzyme complex. These results may prove useful in probing molecular mechanism of ROS-induced peroxidative damage to mitochondria which have been proposed to contribute to aging, ischemia/reperfusion and chronic degenerative diseases.
Circ Res. 2004 Jan 9;94(1):53-9. Epub 2003 Dec 1.
Decrease in mitochondrial complex I activity in ischemic/reperfused rat heart: involvement of reactive oxygen species and cardiolipin.
Paradies G, Petrosillo G, Pistolese M, Di Venosa N, Federici A, Ruggiero FM.
Reactive oxygen species (ROS) are considered an important factor in ischemia/reperfusion injury to cardiac myocytes. Mitochondrial respiration is an important source of ROS production and hence a potential contributor to cardiac reperfusion injury. In this study, we have examined the effect of ischemia and ischemia followed by reperfusion of rat hearts on various parameters related to mitochondrial function, such as complex I activity, oxygen consumption, ROS production, and cardiolipin content. The activity of complex I was reduced by 25% and 48% in mitochondria isolated from ischemic and reperfused rat heart, respectively, compared with the controls. These changes in complex I activity were associated with parallel changes in state 3 respiration. The capacity of mitochondria to produce H2O2 increased on reperfusion. The mitochondrial content of cardiolipin, which is required for optimal activity of complex I, decreased by 28% and 50% as function of ischemia and reperfusion, respectively. The lower complex I activity in mitochondria from reperfused rat heart could be completely restored to the level of normal heart by exogenous added cardiolipin. This effect of cardiolipin could not be replaced by other phospholipids nor by peroxidized cardiolipin. It is proposed that the defect in complex I activity in ischemic/reperfused rat heart could be ascribed to a ROS-induced cardiolipin damage. These findings may provide an explanation for some of the factors responsible for myocardial reperfusion injury.
