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At least 217 records · Page 12Linked to original sources

PubMed2000

Autoantibodies against oxidized low-density lipoprotein and cardiolipin in patients with coronary heart disease.

Autoantibodies against oxidized low density lipoprotein (oxLDL) have been proposed to be independent predictors of atherosclerotic vascular disease. Because the levels of autoantibodies against oxLDL and cardiolipin might be modified by the presentation and severity of coronary heart disease (CHD), we measured their levels in patients with different manifestations of CHD (n=415, mean age 61 years, range 33 to 74 years) in a subset of the European Action on Secondary Prevention through Intervention to Reduce Events (EUROASPIRE) study. There were 109 patients with coronary artery bypass surgery, 106 patients with balloon angioplasty, 101 patients with acute myocardial infarction, and 99 patients with acute myocardial ischemia. Autoantibodies were measured by ELISA. Food records and fatty acid profiles of serum cholesteryl esters were used to evaluate dietary intake. Anti-oxLDL antibodies were significantly higher in the group with acute myocardial infarction than in other groups in men (coronary artery bypass surgery 1.91+/-1. 41, balloon angioplasty 2.11+/-2.19, acute myocardial infarction 2. 52+/-2.05, and acute myocardial ischemia 1.96+/-1.78; P=0.022, mean+/-SD) but not in women. The titers of anti-cardiolipin antibodies did not differ among the patient groups. Neither of the autoantibodies was associated with recurrent coronary events. Anti-oxLDL and anti-cardiolipin autoantibodies were not correlated with serum total cholesterol, high density lipoprotein cholesterol, or triglycerides, except that in women anti-oxLDL antibodies and triglycerides were positively correlated (r=0.225, P=0.011). In men, anti-cardiolipin antibodies were higher in the lowest quartiles of dietary intakes of vitamin E and polyunsaturated fat. Dietary intakes of vitamin E and polyunsaturated fat were correlated (r=0. 588, P<0.001). In conclusion, autoantibodies against oxLDL were associated with myocardial infarction in men. Anti-cardiolipin autoantibodies were inversely correlated with dietary intakes of vitamin E and polyunsaturated fat in men with CHD.

Adult↗

PubMed2001

Effect of cardiolipin on proton permeability of phospholipid liposomes: the role of hydration at the lipid-water interface.

The effect of cardiolipin on the proton permeability of dipalmitoyl-phosphatidylcholine small unilamellar vesicles was examined by utilizing the pH-dependent fluorescence emission of 5- (and 6-) carboxyfluorescein. It has been found that the proton permeability of the phospholipid bilayer was greatly enhanced in the presence of cardiolipin, an acidic phospholipid mainly found in the inner mitochondrial membranes. In the presence of bovine heart cardiolipin, the bilayer surface hydration, as assessed with the fluorescence lifetime of 1-anilinonaphthalene-8-sulfonic acid, was increased, while hydration in the acyl chain region was not altered. In addition, the bilayer fluidity was also not affected. Taken together, these results suggest that the lipid-water interface is the major energy barrier for proton permeation of the bilayer vesicles, and alteration to properties of this interface by cardiolipin headgroup appears to be responsible for the enhanced proton permeability.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1990

Antibodies to cardiolipin and intermediate filaments: a study of autoimmunity in rheumatoid arthritis.

Autoantibodies to cardiolipin and intermediate filaments have both been reported with increased frequency in rheumatoid arthritis. We evaluated the frequency, pathological significance, and diagnostic relevance of these autoantibodies in a series of 124 patients and controls. We studied 81 patients with rheumatoid arthritis, 23 with osteoarthritis, and 20 normals. Antibodies to cardiolipin were measured by an ELISA method and antibodies to intermediate filaments were measured by indirect immunofluorescence using HEp2 cells. Antibodies to cardiolipin were present in 58% of rheumatoid patients and antibodies to intermediate filaments were present in 55% rheumatoid patients. They were both predominantly of IgM class, and were more frequent than in normal or osteoarthritic controls. Correlating levels of both these autoantibodies to clinical and laboratory measures of disease activity such as Ritchie articular index and C-reactive protein level showed that no consistent relationships existed. They were not related to other auto-antibodies such as rheumatoid factors and anti-nuclear antibodies, nor to each other. These results show that antibodies to cardiolipin and intermediate filaments in rheumatoid arthritis are of no diagnostic value, they are not related to disease activity, and have no relationship to other autoimmune disturbances. We suggest that several pathological mechanisms must be involved in the development of autoantibodies in rheumatoid arthritis.

Adult↗

PubMed1976

Turnover of fatty acids in rat liver cardiolipin: comparison with other mitochondrial phospholipids.

Following intraperitoneal administration of 1-14C-linoleic acid or 2-3H-acetate to rats, the specific radioactivities of both liver cardiolipin and other mitochondrial phospholipids after different time intervals were measured. Comparison of the data obtained with those from another stock of rats treated with 32P-phosphate or 2-3H-glycerol showed that the fatty acids of cardiolipin, like those of other phospholipids, exhibit an independent turnover with respect to the remaining parts of the molecule. The half-life of acyl moieties of cardiolipin is ca. 20% higher than that of the same components of other mitochondrial phospholipids. Moreover, it appears that, in both cardiolipin and other phospholipids, linoleyl residues turn over faster than nonessential fatty acids. Discussion is made as to whether this characteristic can be related to the role of phospholipids in the functioning of some enzymes bound to the inner mitochondrial membrane.

Animals↗

PubMed2004

An efficient and novel method for the synthesis of cardiolipin and its analogs.

A novel synthetic method has been developed for cardiolipin and its analog via a chlorophosphoramidite coupling reaction followed by oxidation. The reagent, N,N-diisopropylmethylphosphoramidic chloride, couples effectively with 1,2-O-dimyristoyl-sn-glycerol in the presence of an amidite activator to form a phosphoamidite intermediate, which then reacts with 2-O-benzylglycerol in the presence of a basic catalyst followed by in situ oxidation to give the corresponding protected cardiolipin. Deprotection of the protecting groups provides tetramyristoyl cardiolipin in good overall yield of 60%. The synthetic method is applicable to large-scale synthesis of cardiolipin and various analogs with or without unsaturation for liposomal drug delivery.

Cardiolipins↗

PubMed1988

Synergistic stimulation of pregnenolone synthesis in rat adrenal mitochondria by n-hexane and cardiolipin.

n-Hexane and cardiolipin each stimulate pregnenolone production by isolated rat adrenal mitochondria. Following corticotropin (ACTH) stimulation, mitochondrial cholesterol metabolism exhibits a fast phase lasting 2 min, followed by a 10-fold slower metabolism. ACTH suppression by dexamethazone or cycloheximide (CX) treatment removes this fast phase. n-Hexane, at concentrations approaching 80% of the aqueous solubility limit (approximately 0.08 mM), selectively stimulates the slow phase of metabolism, while cardiolipin (100 microM) stimulates only the fast phase. Other alkanes and ethers are effective. The effect of n-hexane is dependent on mitochondrial integrity, as evidenced by decreased effects in hypoosmotically shocked mitochondria (outer membrane disrupted) and ineffectiveness in sonicated mitochondria (both membranes disrupted). n-Hexane apparently enhances the transfer of outer membrane cholesterol to inner membrane P-450scc. Stimulation by cardiolipin is retained by disrupted mitochondria and may involve enhanced availability of P-450scc to inner membrane cholesterol. When added together, these agents produce more than additive effects on cholesterol metabolism. Preincubation with n-hexane did not increase reactive cholesterol, suggesting that enhanced cholesterol transport occurs only in concert with metabolism of inner membrane cholesterol. Uptake of alkanes into mitochondrial membranes may effect structural changes that facilitate outer to inner membrane cholesterol transfer, but major changes are excluded by the effectiveness of isocitrate as a reductant for P-450scc. In combination, n-hexane and cardiolipin reproduce the effect of the ACTH-sensitive sterol regulatory peptide on mitochondria [R. C. Pedersen and A. C. Brownie (1983) Proc. Natl. Acad. Sci. USA 80, 1882-1886], suggesting that peptide action on adrenal mitochondria may resolve into two analogous components.

Adrenal Glands↗

PubMed1981

Cardiolipins are 'in vitro' inhibitors of rat brain (Na+ + K+)-dependent ATPases. A probable mechanism of action.

Cardiolipins were found to potentiate the 'in vitro' inhibitory activity of (-)-delta 9-tetrahydrocannabinol on (Na+ + K+)-dependent rat brain ATPases. The compounds were found to be powerful inhibitors by themselves. At optimal concentrations of cations (Na+, K+, Mg2+), the compounds were found to be noncompetitive inhibitors of ATP (Ki = 3.5 x 10(-6) M) and 'uncompetitive' inhibitors of Na+. From gas-liquid chromatographic analysis of the cardiolipin preparations it can be inferred that their effectiveness as inhibitors is related to the linoleic acid contents. The preliminary data presented here suggest that cardiolipins inhibit the Na+-dependent phosphorylation step in the hydrolysis of ATP. Based on the observations reported in this work, a hypothesis is presented suggesting that there may be a functional or evolutionary explanation for the paucity of cardiolipins in cell plasma membranes.

Animals↗

PubMed1982

Further aspects of the Ca2+-dependent polymorphism of bovine heart cardiolipin.

The influence of cations on the structure of aqueous dispersions of the sodium salt of bovine heart cardiolipin was investigated using binding experiments, 31P-NMR, freeze-fracture electron microscopy, small angle X-ray diffraction and batch calorimetry techniques. In the 1-3 mM concentration range, Ca2 induces a bilayer leads to hexagonal HII transition for the lipid. During this transition there is a marked increase in Ca2+ binding from a maximum of 0.35 Ca/cardiolipin in the bilayer to 1.0 Ca/cardiolipin in the hexagonal HII phase. Only when the cardiolipin liposomes are exposed to locally high Ca2+ concentrations is the bilayer leads to hexagonal HII transition accompanied by the appearance of an intermediate 'isotropic' structure characterized by an isotropic 31P-NMR signal and lipidic particles. In contrast, in mixed dioleoylphosphatidylcholine/cardiolipin (1:1) liposomes, Ca2+ concentrations as low as 100 microM will induce an 'isotropic' structure under conditions where no locally high Ca2+ concentrations can occur. In this system at higher Ca2+ concentrations (above 5 mM) the hexagonal HII phase formation occurs. At least 80% of the phosphatidylcholine can be incorporated into this phase. The Ca2+ -induced bilayer to hexagonal transition is an endothermic reaction with a delta H of approx. 1.8 kcal/mol. Removal of Ca2+ from the hexagonally organized calcium-cardiolipin (1:1) complex by dialysis is an extremely slow process with a half-time in excess of 80 h. After 23 h of dialysis at a Ca/cardiolipin ratio of 0.86 an 'isotropic' structure is observed, characterized by an isotropic 31P-NMR signal and the presence of lipidic particles. After 70 h of dialysis (Ca/cardiolipin = 0.7) a new phase is observed. This phase which is optically isotropic and highly viscous separates from a lipid-free aqueous phase and contains 111 mM cardiolipin (15.5% by weight). The phospholipid molecules undergo rapid isotropic motion and the freeze-fracture morphology indicates the presence of a highly curved interconnected bilayer network separating various aqueous compartments. No defined X-ray diffraction bands can be observed for this phase. These characteristics are typical for cubic phases. This phase is metastable as mechanical agitation immediately induces the formation of large bilayer vesicles.

Animals↗

PubMed1985

Molecular aspects of the bilayer stabilization induced by poly(L-lysines) of varying size in cardiolipin liposomes.

The interaction between poly(L-lysines) of varying size with cardiolipin was investigated via binding assays, X-ray diffraction, freeze-fracture electron microscopy, and 31P- and 13C-NMR. Binding of polylysines to the lipid only occurred when three or more lysine residues were present per molecule. The strength of the binding was highly dependent on the polymerization degree, suggesting a cooperative interaction of the lysines within the polymer. Upon binding, a structural reorganization of the lipids takes place, resulting in a closely packed multilamellar system in which the polylysines are sandwiched in between subsequent bilayers. Acyl chain motion is reduced in these liquid-crystalline peptide-lipid complexes. From competition experiments with Ca2+ it could be concluded that when the affinity of the polylysine for cardiolipin was much larger than that of Ca2+, a lamellar polylysine-lipid complex was formed, irrespective of whether an excess of Ca2+ was added prior to or after the polypeptide. When the affinity of the polylysine for cardiolipin was less or of the same order as that of Ca2+, the lipid was organized in the hexagonal HII phase in the presence of Ca2+. These results are discussed in the light of the peptide specificity of bilayer (de)stabilization in cardiolipin model membranes.

Calcium↗

PubMed1985

Association of spin-labelled cardiolipin with dimyristoylphosphatidylcholine-substituted bovine heart cytochrome c oxidase. A generalized specificity increase rather than highly specific binding sites.

The endogeneous lipid of bovine heart cytochrome c oxidase has been replaced by dimyristoylphosphatidylcholine using cholate-mediated exchange. The lipid-substituted preparation contained less than 1 mole cardiolipin per mole enzyme and possessed full oxidative activity. The association of spin-labelled cardiolipin with such lipid-substituted cytochrome oxidase preparations has been assayed using ESR spectroscopy. An average relative association constant 5.4-times that for phosphatidylcholine is obtained for cardiolipin. Measurements on preparations with increasing contents of unlabelled cardiolipin, introduced during lipid exchange, reveal that this selectivity corresponds to a generalized increase in specificity for all lipid association sites on the protein.

Animals↗

PubMed1980

Cardiolipin, a major phospholipid of Gram-positive bacteria that is not readily extractable.

Extraction of phospholipids from stationary phase grown cells of the Gram+ bacteria, Bacillus megaterium, Bacillus subtilis, Bacillus cereus and Micrococcus lysodeikticus was found to be incomplete with various commonly used extraction procedures. Phosphatidylglycerol and phosphatidylethanolamine were readily extracted but up to 95% of the cardiolipin appeared to be retained within the cell residue. Extraction of the cardiolipin could be slightly enhanced by increasing the temperature or the acidity of the extraction solutions but complete extraction was obtained only after lysozyme treatment of intact cells or cell residues remaining after extraction. In addition complete extraction could be observed in the case of cells harvested in the early logarithmic phase. Freeze-fracture electron microscopy was carried out on the cell residue remaining after extraction of all phospholipids except cardiolipin. A fracture plane through the plasma membrane could not be observed anymore. Instead fracture planes through lipid vesicles were observed. These vesicles reside within the remnants of the cytoplasm and consist most likely of the non-extracted cardiolipin.

Bacillus↗

PubMed1985

FAD-dependent malate dehydrogenase from Mycobacterium smegmatis: activation of the lipid-depleted enzyme by incorporation into cardiolipin liposome.

The lipid-depleted, enzymatically inactive malate dehydrogenase isolated from Mycobacterium smegmatis membrane was found to be incorporated spontaneously into cardiolipin liposome, but not into phosphatidylcholine liposome, as was revealed by electron spin resonance spectra with the use of 5-doxylstearic acid as a spin probe in the phospholipid liposomes. In addition, sucrose density gradient centrifugation in 0.5 M KCl showed hydrophobic interaction of the enzyme with cardiolipin liposome and further proved that the enzyme thus interacted hydrophobically with cardiolipin liposome became enzymatically active. From the results obtained above, it was concluded that the lipid-depleted, enzymatically inactive malate dehydrogenase isolated from M. smegmatis membrane was found to be activated by incorporating into the hydrophobic region of cardiolipin liposome.

Cardiolipins↗

PubMed1993

Active increase in cardiolipin synthesis in the stationary growth phase and its physiological significance in Escherichia coli.

Activity of the Escherichia coli cardiolipin synthase, encoded by cls, increased about 10-fold in the stationary growth phase, while other committed-step enzymes in phospholipid biosynthesis rather decreased. A null cls mutant lost viability to 10(-4) of the wild-type cells during the prolonged incubation for 5 days. Cardiolipin was most stable among membrane phospholipids during the incubation. Accordingly, cardiolipin should play a role in survival of the cell and E. coli employs a sophisticated way to form cardiolipin according to need even under non-growing conditions.

Cardiolipins↗

PubMed1994

Human epidermal cells progressively lose their cardiolipins during ageing without change in mitochondrial transmembrane potential.

Mitochondria dysfunction is considered to be a major cause of the modifications that occur during cell ageing. For this reason, cardiolipin, a suitable marker of the chondriome, as well as the mitochondrial transmembrane potential were examined in keratinocytes obtained from 9- to 75-year-old women. The study was carried out by flow cytometry using two fluorescent mitochondria probes: nonyl acridine orange, which binds specifically to cardiolipin, and rhodamine 123, which is incorporated mainly in response to transmembrane potential. Cardiolipin levels in cells from elderly donors (75 years old) would be 57% lower (r = 0.540; P = 0.0002) than those in children (9 years old), while the inner transmembrane potential remained unchanged (r = 0.0394; P = 0.8017). The stability of the membrane potential may be explained by either or both of the following hypotheses: (i) the same pool of organelles able to maintain membrane potential is conserved even when cardiolipin levels decrease (ii) mitochondria membrane potential does indeed decrease with age but is compensated by glycolysis energy production. Finally, it may be stated that the fluorescent probes nonyl acridine orange and rhodamine 123 might be of interest in testing the phenotype of senescent cells and would be useful in screening the role of certain specific genes in cell ageing.

Adolescent↗

PubMed1991

Cerebrospinal fluid anti-cardiolipin antibodies in neurological diseases.

We studied, with sensitive ELISAs, the anti-cardiolipin antibodies of the G, A, and M classes in the cerebrospinal fluid (CSF) and serum of 179 neurological patients. The CSF and serum of 2 systemic lupus erythematosus (SLE) patients presented IgG anti-cardiolipin antibodies in corresponding levels. Anti-cardiolipin antibodies were produced within the central nervous system in neurosyphilis (A and M classes), in some patients affected by multiple sclerosis (G or M class), in two cases of Guillain-Barré syndrome (G and A classes), and in one AIDS patient (G class). The CSF anti-cardiolipin antibodies detected in our study suggest a local immune reaction against brain phospholipids in SLE and in human demyelinating disorders.

Antibodies↗

PubMed1989

Laser time-resolved fluorescence study of the interaction between anthracyclines and cardiolipin.

The molecular interaction between cardiolipin vesicles and two representative anthracyclines, daunomycin and 5-iminodaunomycin, has been studied at pH 7.1 by laser time-resolved fluorescence, for a cardiolipin-to-anthracycline ratio r ranging from 0.02 to 5. The fluorescence lifetime of daunomycin is 1.03 ns. For r = 0.3 - 5 a longer-lived transient (1.91 - 1.49 ns) is present and originates from the excitation of daunomycin bound on a single phosphate group of cardiolipin. At r = 0.3 two lifetimes are observed, the second one being due, partially, to free daunomycin and bound drug molecules embedded in the lipid bilayer. The fastest-decaying species is present for r = 0.5 - 2.0 and identified as two adjacent, stacked-up daunomycin molecules bound onto the two phosphate groups of the cardiolipin. In the case of 5-iminodaunomycin, a less cardiotoxic analogue, three-exponential decay is never observed and a fast-decaying component, pi approximately 0.2 ns, is already present at low r and vanishes for r greater than 0.5. The constancy of the lifetimes of the longer-lived species may originate from the reorientation of the bound drug from the hydrophilic to the lipid domain.

Antibiotics, Antineoplastic↗

PubMed2006

Electrochemical analysis of the effect of Ca2+ on cardiolipin-cytochrome c interaction.

Mitochondrial Ca2+ has been considered a trigger for the release of cytochrome c, which is a critical and early event in the induction of cell apoptosis, although the molecular mechanism underlying this effect is still not fully understood. Here we investigate the interaction between cytochrome c and cardiolipin and the effect of Ca2+ on this interaction using electrochemical methods. Experimental results revealed that modification of cardiolipin onto the surface of a pyrolytic graphite electrode could lead to a rapid direct electron transfer of cytochrome c through the electrostatic interaction between the protein and the cardiolipin. Addition of Ca2+ to the test solution containing cytochrome c could cause the decrease of the redox peaks of the protein, and the peaks could be recovered when Ca2+ was chelated by ethylenediaminetetraacetate. The cardiolipin-cytochrome c interaction and the Ca2+ effect were also investigated with the variation of the charges of lipids, buffer solutions, reaction time, and valencies of cations for comparison.

Animals↗

PubMed2005

The interaction between tBid and cardiolipin or monolysocardiolipin.

Bid, a BH3-only pro-apoptotic member of the Bcl-2 family, is cleaved by caspase 8 in apoptosis induced by death domain receptors. The carboxyl terminus of the cleavage product, tBid, remains associated with the amino terminal fragment (nBid) after cleavage. Dissociation of tBid from nBid occurs during targeting of tBid to mitochondria. We use an in vitro system and demonstrate that cardiolipin is sufficient for the dissociation. Monolysocardiolipin, a metabolite of cardiolipin that increases in mitochondria during apoptosis, has the same affinity to tBid as cardiolipin and is also capable of inducing dissociation of tBid from nBid. In contrast, phosphatidylethanolamine could not induce dissociation of tBid from nBid. To determine the site of tBid that interacts with cardiolipin, we performed mutational analysis by eliminating the positive-charged residues in helices 4-6. None of the single mutations can abolish the ability of tBid to target to mitochondria and to induce cytochrome c release, suggesting that positive-charged residues in helices 4-6 may not be required for mitochondrial targeting of tBid.

BH3 Interacting Domain Death Agonist Protein↗