Choline-containing Phospholipids Research Articles

Magnetic resonance spectroscopy of limbic structures displays metabolite differences in young unaffected relatives of schizophrenia probands

Imaging studies of schizophrenia patients showed fronto-temporal brain volume deficits, while magnetic resonance spectroscopy (MRS) studies of patients and unaffected biological relatives have found a decrement of the neuronal marker N-acetyl-aspartate (NAA) in the hippocampus and frontal lobes, and increased choline-containing phospholipids. Using a 3 T MR scanner, we determined the metabolite profile within limbic regions (anterior cingulate cortex (ACC) and left hippocampus) of 36 unaffected, adolescent/young adult relatives of schizophrenia probands (first-degree = 16, second-degree = 20) and 25 healthy controls with no family history of schizophrenia. Significant main effects of group were found on NAA/Cho ratios for both the left hippocampus (F = 6.11, p ≤ 0.02) and ACC (F = 4.89, p ≤ 0.03) as well as for the left hippocampus Cho/Cr ratio (F = 5.55, p ≤ 0.02). Compared to age and sex matched healthy controls without a family history of schizophrenia, first-degree relatives of probands had greater MRS metabolite deviations than second-degree relatives. Greater familial proximity to the schizophrenia proband (or higher schizophrenia susceptibility) among biological relatives was associated with stepwise lowering of NAA/Cho and elevations in Cho/Cr ratios. The observed limbic metabolite changes among young, nonpsychotic biological relatives are likely related to shared genetic vulnerability factors, and may assist in the early identification of schizophrenia for primary and secondary prevention.

Release of adrenaline by anaphylaxis in the guinea-pig: its effect on lung lipid content

The study was undertaken to discover whether the catecholamines released as a result of the stress and hypoxia of anaphylaxis were responsible for the concomitant loss of lipid from the lung. A method is described whereby the respiratory rate and volume and heart-rate of conscious sensitized guinea-pig were measured and the electrocardiogram recorded during anaphylaxis induced by aerosolized antigen. After 7 days or more, some animals were anaesthetized with pentobarbitone and respiration was artificially maintained at the level recorded in the conscious state, whilst the quantity of catecholamines liberated during anaphylaxis was assayed using an extra-corporeal blood circulation to superfuse smooth muscle preparations. In other animals of the same group, it was shown that intravenous infusion of adrenaline in a similar quantity to that detected in the circulation following anaphylaxis (0.3 mug min-(-1) for 40 min) caused losses of triglyceride and partial glycerides from the lungs. Thus, the loss of choline-containing phospholipid was attributed to the direct effects of the anaphylactic reaction on the lung tissue.

Effects of prepartum ruminally protected choline supplementation on performance of beef cows and calves

Prepartum supplementation of spring-calving beef cows is a vital part of cow-calf enterprises, often affecting subsequent reproductive success. Most research in the area of prepartum supplementation has focused on provision of either energy or protein; only modest attention has been given to the use of supplemental micronutrients. One such micronutrient is choline. Choline is classified generally as a B vitamin and is an essential nutrient. Phosphatidylcholine and other choline-containing lipids maintain the structural integrity of cellular membranes and play a vital role in metabolism of dietary fat. Choline-containing phospholipids are also important precursors for intracellular-messenger molecules and cell-signaling molecules critical to the reproductive process. Choline is commonly found in feedstuffs and forages but is highly degradable in the rumen. For choline supply to be increased effectively, it must be offered in a form that is resistant to ruminal digestion. This can be achieved by encapsulating choline in lipid. Therefore, the objective of our study was to evaluate the effect of prepartum ruminally protected choline supplementation on cow and calf performance.

Effect of choline-containing phospholipids on brain cholinergic transporters in the rat

The influence of one week treatment with the choline-containing phospholipids cytidine-5′-diphosphocholine (CDP-choline) and choline alphoscerate (L-alpha-glyceryl-phosphorylcholine) at choline-equivalent doses (CDP-choline: 325 mg/kg/day; choline alphoscerate: 150 mg/kg/day) on vesicular acetylcholine transporter (VAChT), on choline transporter (CHT) and on acetylcholine (ACh) concentrations was investigated in rat frontal cortex, striatum and cerebellum. ACh was assayed by HPLC with electrochemical detection, VAChT by Western blot, ELISA and immunohistochemistry, CHT by Western blot and immunohistochemistry. After CDP-treatment, ACh levels were slightly increased in the frontal cortex, not substantially different in the striatum, and reduced significantly in the cerebellum compared to controls. Choline alphoscerate stimulated significantly the neurotransmitter concentration in the frontal cortex, however, the levels were similar to the controls in both the striatum and cerebellum. In comparison to the controls, VAChT expression following either CDP-choline or choline alphoscerate treatment, was enhanced greatly in the striatum and cerebellum. Also, ELISA measurements for VAChT showed significant increases in all choline alphoscerate treated brain areas. In contrast, in the CDP-choline treated rats the vesicular transporter amount was greater than the control only in the striatum. The cholinergic presynaptic transporters VAChT and CHT play a relevant role in sustaining new ACh synthesis and release. To sum up, CDP-choline and choline alphoscerate stimulated to a different extent the expression of VAChT and CHT primarily in a cognitive area such as frontal cortex. In the lack of novel therapeutic strategies, safe compounds developed since a long time such as the choline-containing phospholipids investigated would merit to be further investigated by new and adequate clinical studies. This for assessing their place if any in pharmacotherapy of dementia disorders characterized by diminished cholinergic tone.

Identification of phospholipids in human meibum by nano-electrospray ionisation tandem mass spectrometry

Meibum is believed to be the major source of tear film lipids, which are vital in the prevention of excess evaporation of the aqueous phase. The complete lipid composition of meibum has yet to be established. While earlier studies reported the presence of phospholipids in human meibum, recent mass spectrometric studies have not detected them. In this study we use electrospray ionisation tandem mass spectrometry to investigate the presence of phospholipids in meibum and provide comparison to the phospholipid profile of tears. Lipids were extracted from human meibum and tear samples using standard biphasic methods and analysed by nano-electrospray ionisation tandem mass spectrometry using targeted ion scans. A total of 35 choline-containing phospholipids were identified in meibum and the profile of these was similar to that observed in tears, suggesting tear lipids are derived from meibum. The results shown here highlight the need for a combination of optimised techniques to enable the identification of the large range of lipid classes in meibum.

31P NMR of phospholipid metabolites in prostate cancer and benign prostatic hyperplasia

(1)H MRSI in vivo is increasingly being used to diagnose prostate cancer noninvasively by measurement of the resonance from choline-containing phospholipid metabolites. Although (31) P NMR in vivo or in vitro is potentially an excellent method for probing the phospholipid metabolites prominent in prostate cancer, it has been little used recently. Here, we report an in vitro (31)P NMR comparison of prostate cancer and benign prostatic hyperplasia, focusing on the levels of the major phospholipid metabolites. Unlike phosphocholine and glycerophosphocholine, phosphoethanolamine and glycerophosphoethanolamine (and their ratio) were significantly different between cancer and benign prostatic hyperplasia. The high level of phosphoethanolamine+glycerophosphoethanolamine relative to phosphocholine+glycerophosphocholine suggests that the former may be significant contributors to the "total choline" resonance observed by (1)H MRSI in vivo.

Aggregated Electronegative Low Density Lipoprotein in Human Plasma Shows a High Tendency toward Phospholipolysis and Particle Fusion

Aggregation and fusion of lipoproteins trigger subendothelial retention of cholesterol, promoting atherosclerosis. The tendency of a lipoprotein to form fused particles is considered to be related to its atherogenic potential. We aimed to isolate and characterize aggregated and nonaggregated subfractions of LDL from human plasma, paying special attention to particle fusion mechanisms. Aggregated LDL was almost exclusively found in electronegative LDL (LDL(-)), a minor modified LDL subfraction, but not in native LDL (LDL(+)). The main difference between aggregated (agLDL(-)) and nonaggregated LDL(-) (nagLDL(-)) was a 6-fold increased phospholipase C-like activity in agLDL(-). agLDL(-) promoted the aggregation of LDL(+) and nagLDL(-). Lipoprotein fusion induced by α-chymotrypsin proteolysis was monitored by NMR and visualized by transmission electron microscopy. Particle fusion kinetics was much faster in agLDL(-) than in nagLDL(-) or LDL(+). NMR and chromatographic analysis revealed a rapid and massive phospholipid degradation in agLDL(-) but not in nagLDL(-) or LDL(+). Choline-containing phospholipids were extensively degraded, and ceramide, diacylglycerol, monoacylglycerol, and phosphorylcholine were the main products generated, suggesting the involvement of phospholipase C-like activity. The properties of agLDL(-) suggest that this subfraction plays a major role in atherogenesis by triggering lipoprotein fusion and cholesterol accumulation in the arterial wall.

Imaging endpoints to predict response to IGF1R/IR inhibition in CRC models

Abstract Colorectal cancer (CRC) represents a major health burden and accounts for nearly 10% of all cancer-related deaths in the U.S. Among the many new pathways being exploited for cancer treatment is the insulin-like growth factor receptor (IGF1R) signaling pathway, which appears to be a robust target in CRC (e.g., hyperactivated in more than 50% of CRC patients). OSI-906 is a novel selective dual inhibitor IGF-1R and IR kinase activities. Despite advances in molecular predictive markers, a substantial proportion of patients selected for targeted therapy has nonresponsive tumors and require additional combination-based regimens. Unlike cytotoxic chemotherapeutic agents, most novel signal transduction modulators (STMs) induce only modest tumor regression, thus there is significant need for establishing functional pharmacodynamic (e.g., therapy response) endpoints for inhibition of signaling via particular pathways. In the present study we established noninvasive imaging-based endpoints for response to OSI-906 in CRC mouse models. Female nude mice were implanted with either of two human CRC cell lines (one sensitive and one resistant) or individual human surgical CRC explants (with unknown sensitivity). Metabolic changes (decreased glucose uptake and lactate production by FDG-PET and proton MRS, respectively) were apparent in OSI-906-sensitive xenografts as early as 2 days post-treatment when no changes in tumor size were yet detected. A significant decrease in tumor size and membrane choline-containing phospholipids by MRI and MRS, respectively, were seen after 27 days of treatment in OSI-906-sensitive xenografts. No changes in FDG-PET, MRS, or tumor progression were observed in OSI-906 resistant xenografts. Our data indicate that noninvasive functional imaging endpoints can provide early and sensitive markers for cytostatic action of IGF1R/IR inhibitors. This talk is also presented as Poster A14.

Elucidation of Phosphatidylcholine Composition in Krill Oil Extracted from Euphausia superba

High performance liquid chromatography-electrospray tandem mass spectrometry was used to elucidate the phospholipids in krill oil extracted from Euphausia superba, an emerging source for human nutritional supplements. The study was carried out in order to map the species of the choline-containing phospholipid classes: phosphatidylcholine and lyso-phosphatidylcholine. In addition, the prevalent phosphatidylcholine class was quantified and the results compared with prior analysis. The qualification was performed with separation on a reverse phase chromatography column, while the quantification was obtained with class separation on a normal phase chromatography column. An Orbitrap system was used for the detection, and pulsed-Q dissociation fragmentation was utilized for the identification of the species. An asymmetrical exclusion list was applied for detection of phospholipid species of lower concentration, significantly improving the number of species observed. A total of 69 choline-containing phospholipids were detected, whereof 60 phosphatidylcholine substances, among others seven with probable omega-3 fatty acids in both sn-1 and sn-2. The phosphatidylcholine concentration was estimated to be 34 ± 5 g/100 g oil (n = 5). These results confirm the complexity of the phospholipid composition of krill oil, and the presence of long chained, heavily unsaturated fatty acids.

Simultaneous quantification of glycine- and taurine-conjugated bile acids, total bile acids, and choline-containing phospholipids in human bile using 1H NMR spectroscopy

Bile acids, phospholipids, and cholesterol are the major lipid components in human bile. The composition of bile is altered in various cholestatic diseases, and determining such alterations will be of great clinical importance in understanding the pathophysiology of these diseases. A robust method for the simultaneous quantification of major biliary lipids – glycine-conjugated bile acids (GCBAs), taurine-conjugated bile acids (TCBAs), total bile acids (TBAs) and choline-containing phospholipids (choline-PLs) has been devised using 1H NMR spectroscopy. Bile samples were obtained from patients with various hepatopancreatobiliary diseases ( n = 10) during an endoscopic retrograde cholangiopancreatography (ERCP) examination. Peak areas of metabolite-signals of interest were obtained simultaneously by deconvoluting the experimental spectrum, making the present method robust. GCBAs and TCBAs have been quantified using the peak areas of their characteristic methylene (CH 2) signals resonating at 3.73 and 3.07 ppm, whereas TBA and choline-PLs were quantified using their methyl (CH 3) and trimethylammonium (–N +(CH 3) 3) signals resonating at 0.65 and 3.22 ppm respectively. The present method was compared with an NMR-based literature method (which involves dissolving bile in DMSO), and a good correlation was observed between the two methods with regression coefficients – 0.97, 0.99, 0.98 and 0.93 for GCBAs, TCBAs, TBAs, and choline-PLs respectively. This method has the potential to be extended to in vivo applications for the simultaneous quantification of various biliary lipids non-invasively.

Pharmacological inhibition of ABCA1 degradation increases HDL biogenesis and exhibits antiatherogenesis

Expression of ABCA1 is regulated by transcription of the gene and calpain-mediated proteolytic degradation, and inhibition ABCA1 degradation results in increased ABCA1 and HDL biogenesis in vitro. We examined whether this approach could be a potential antiatherogenic treatment. Although probucol inhibits both the activity and degradation of ABCA1, its oxidized products, spiroquinone and diphenoquinone, reduce degradation of ABCA1 without inhibiting its activity or altering transcription of the ABCA1 gene. Accordingly, both compounds enhanced apolipoprotein A-I/ABCA1-dependent generation of HDL in vitro, and increased hepatic ABCA1 and plasma HDL without increasing antioxidant activity in plasma when given to rabbits. Both compounds also decreased vascular lipid deposition in cholesterol-fed rabbits. We therefore conclude that stabilization of ABCA1 against calpain-mediated degradation is a novel and potentially important strategy to increase HDL formation and prevent atherosclerosis. Spiroquinone and diphenoquinone are potential seeds for development of such drugs.

Peroxisome proliferator-activated receptor delta activation leads to increased transintestinal cholesterol efflux

Peroxisome proliferator-activated receptor delta (PPARdelta) is involved in regulation of energy homeostasis. Activation of PPARdelta markedly increases fecal neutral sterol secretion, the last step in reverse cholesterol transport. This phenomenon can neither be explained by increased hepatobiliary cholesterol secretion, nor by reduced cholesterol absorption. To test the hypothesis that PPARdelta activation leads to stimulation of transintestinal cholesterol efflux (TICE), we quantified it by intestine perfusions in FVB mice treated with PPARdelta agonist GW610742. To exclude the effects on cholesterol absorption, mice were also treated with cholesterol absorption inhibitor ezetimibe or ezetimibe/GW610742. GW601742 treatment had little effect on plasma lipid levels but stimulated both fecal neutral sterol excretion ( approximately 200%) and TICE ( approximately 100%). GW610742 decreased intestinal Npc1l1 expression but had no effect on Abcg5/Abcg8. Interestingly, expression of Rab9 and LIMPII, encoding proteins involved in intracellular cholesterol trafficking, was increased upon PPARdelta activation. Although treatment with ezetimibe alone had no effect on TICE, it reduced the effect of GW610742 on TICE. These data show that activation of PPARdelta stimulates fecal cholesterol excretion in mice, primarily by the two-fold increase in TICE, indicating that this pathway provides an interesting target for the development of drugs aiming at the prevention of atherosclerosis.

CHOLINE OR CDP-CHOLINE ALTERS SERUM LIPID RESPONSES TO ENDOTOXIN IN DOGS AND RATS: INVOLVEMENT OF THE PERIPHERAL NICOTINIC ACETYLCHOLINE RECEPTORS

We showed previously that choline administration protects dogs from endotoxin-induced multiple organ injury and platelet dysfunctions. Because sepsis/endotoxemia is associated with alterations in lipid metabolism, we have investigated whether choline or cytidine-5'-diphosphate choline, a choline donor, alters serum lipid responses to endotoxin in dogs and rats. In response to endotoxin, serum concentrations of triglycerides, choline-containing phospholipids, total cholesterol, and high-density lipoprotein cholesterol increased in a dose- and time-related manner. Administration of choline (20 mg/kg i.v. in dogs or 90 mg/kg i.p. in rats) or cytidine-5'-diphosphate choline (70 mg/kg i.v. in dogs) 5 min before and 4 and 8 h after endotoxin blocked or attenuated the increases in serum triglycerides, total cholesterol, and nonesterified fatty acids. Endotoxin-induced elevations in serum phospholipid levels did not change in rats and were enhanced in dogs by choline. In rats, serum lipid response to endotoxin was accompanied by severalfold elevations in serum levels of hepatorenal injury markers; their elevations were also blocked by choline. Pretreatment with hexamethonium blocked choline's effects on serum lipids and hepatorenal injury markers. Pretreatment with atropine blocked endotoxin-induced elevations in serum lipid and hepatorenal injury markers, but failed to alter choline's actions on these parameters. Choline treatment improved survival rate of rats in lethal endotoxin shock. In conclusion, these data show that choline treatment alters serum lipid responses to endotoxin and prevents hepatorenal injury during endotoxemia through a nicotinic acetylcholine receptor-mediated mechanism. Hence, choline and choline-containing compounds may have a therapeutic potential in the treatment of endotoxemia/sepsis.

Systematic analysis of choline-containing phospholipids using multi-dimensional mass spectrometry-based shotgun lipidomics

Herein, a systematic study on the identification and quantitation of choline-containing phospholipid molecular species, including choline glycerophospholipid (PC), lysoPC, and sphingomyelin (SM), is described using multi-dimensional mass spectrometry-based shotgun lipidomics after intrasource separation (MDMS-SL). Current methods for analysis of choline-containing lipids were improved through multiple modifications leading to: (1) identification of constituents present in the PC and SM classes, subclasses of PC, and individual molecular species using MDMS-SL analysis in the positive-ion mode; (2) identification of the fatty acyl constituents and their regiospecificity in diacyl PC molecular species through the neutral loss of trimethylamine plus fatty acids; (3) direct identification of the alkenyl chains of plasmenylcholine species using precursor ion scans of the fragment ions carrying the alkenyl chains; (4) elimination of the effects of polyunsaturation on the quantitation of PC species by multiple ratiometric comparisons; (5) accurate identification and quantitation of lysoPC molecular species including regioisomers by diagnostic fragment ions; and (6) accurate identification and quantitation of SM molecular species by neutral loss scans of phosphocholine plus methyl aldehyde which is specific to SM molecular species. With these enhancements, the application of MDMS-SL for the analyses of choline-containing phospholipid molecular species in biomedical research has been extended to a much larger number of molecular species with greater quantitative accuracy and an increased depth of structural information.

Specific, rapid, and sensitive enzymatic measurement of sphingomyelin, phosphatidylcholine and lysophosphatidylcholine in serum and lipid extracts

ObjectiveHuman serum sphingomyelin (SM) and phosphatidylcholine (PC) play important roles in the development of atherosclerosis. However, there are no rapid and sensitive methods for SM and PC measurement. The present report describes a novel enzymatic method for measuring SM, PC and lysophosphatidylcholine (lyso-PC) levels in plasma and lipid extracts. Design and methodsThe total choline-containing phospholipids (total PL), SM and PC were measured using a two-reagent system involving specific enzymes for choline-based phospholipids. The procedure was performed using either microplate or automatic analyzer technology. The concentration of lyso-PC was calculated by subtracting the concentration of SM plus PC from the total PL concentration. ResultsAssay results showed linear correlations between sample concentration and absorbance. The within-run and between-run coefficients of variation for PC, SM, and lyso-PC concentrations were 2.0–4.4% for the microplate analyzer and 0.9–2.9% for the automatic analyzer. Analysis of normal human serum showed that the total PL concentration strongly correlated with the SM plus PC concentration (r=0.9850). There were moderate correlations between serum PC and SM levels (r=0.6228) and between serum PC and lyso-PC levels (r=0.7806). SM, PC, and lyso-PC levels in normal human serum (n=50) were 0.54±0.07, 1.99±0.22 and 0.60±0.15 mmol/L, respectively. ConclusionThe present enzymatic method allowed for rapid, simple, and accurate measurement of SM, PC, and lyso-PC levels in lipid extracts and in serum. The method is suitable for both microplate and automatic analyzer assays.

Human lens lipids differ markedly from those of commonly used experimental animals

Electrospray ionisation tandem mass spectrometry has allowed the unambiguous identification and quantification of individual lens phospholipids in human and six animal models. Using this approach ca. 100 unique phospholipids have been characterised. Parallel analysis of the same lens extracts by a novel direct-insertion electron-ionization technique found the cholesterol content of human lenses to be significantly higher ( ca. 6 times) than lenses from the other animals. The most abundant phospholipids in all the lenses examined were choline-containing phospholipids. In rat, mouse, sheep, cow, pig and chicken, these were present largely as phosphatidylcholines, in contrast 66% of the total phospholipid in Homo sapiens was sphingomyelin, with the most abundant being dihydrosphingomyelins, in particular SM(d18:0/16:0) and SM(d18:0/24:1). The abundant glycerophospholipids within human lenses were found to be predominantly phosphatidylethanolamines and phosphatidylserines with surprisingly high concentrations of ether-linked alkyl chains identified in both classes. This study is the first to identify the phospholipid class (head-group) and assign the constituent fatty acid(s) for each lipid molecule and to quantify individual lens phospholipids using internal standards. These data clearly indicate marked differences in the membrane lipid composition of the human lens compared to commonly used animal models and thus predict a significant variation in the membrane properties of human lens fibre cells compared to those of other animals.

Sensitive Determination of Reactive Oxygen Species by Chemiluminescence Methods and Their Application to Biological Samples and Health Foods

Sensitive and selective methods, based on chemiluminescence reactions, were introduced for determination of reactive oxygen species (ROS) and their applications to biological samples and health foods. First, a sensitive method for determination of H(2)O(2) by peroxyoxalate chemiluminescence (PO-CL) was developed. This method could be applied to determine small amounts of H(2)O(2) in cola drinks and bacterial contamination of food items. Secondly, the combination of immobilized enzyme column reactor, or ultraviolet irradiation system, with the PO-CL detection method was able to determine clinical substrates (i.e. choline-containing phospholipids, polyamines and D-amino acids) and organic peroxides. Also, an evaluation method of the quenching effect of luminol chemiluminescence against ROS was developed. The sensitive, rapid and precise measurement of the quenching effect against ROS such as superoxide, singlet oxygen, hydroxyl radical, peroxynitrite and hypochlorous ion was achieved. The proposed method could be applied to rosemary extracts, natural colorants and grape seed extracts.

Effect of Choline-Containing Phospholipids on Transglutaminase Activity in Primary Astroglial Cell Cultures

The aim of the present investigation was to study the effects of choline and choline-containing phospholipids CDP-choline (CDPC) and L-alpha-glyceryl-phosphorylcholine (AGPC) on transglutaminase (TG) activity and expression in primary astrocyte cultures. TG is an important Ca2+-dependent protein that represents a normal constituent of nervous systems during fetal stages of development, playing a role in cell signal transduction, differentiation, and apoptosis. Confocal laser scanning microscopy (CLSM) analysis showed an increase of TG activity in astrocyte cultures treated with choline, CDPC, or AGPC at 0.1 μM or 1 μM concentrations. Comparatively, AGPC induced the most conspicuous effects enhancing monodansyl-cadaverine fluorescence both in cytosol and in nuclei, supporting the evidence of the important role played by AGPC throughout differentiation processes tightly correlated to nucleus-cytosol cross- talk during astroglial cells proliferation and development. Western blot analysis showed that in 24h 1 μM AGPC and choline-treated astrocytes increased TG-2, whereas no effect was observed in 24h 1 μM CDP-choline treated astrocytes. Our data suggest a crucial role of choline precursors during different stages of astroglial cell proliferation and differentiation in cultures.

Relation of Baseline Plasma Phospholipid Levels to Cardiovascular Outcomes at Two Years in Men With Acute Coronary Syndrome Referred for Coronary Angiography

In addition to cholesterol and triglycerides, plasma also contains phospholipids. The choline-containing phospholipids constitute >90% of total plasma phospholipids. To date, no studies have looked specifically at the prognostic significance of total phospholipids in patients with known or suspected coronary artery disease. The present study investigated the long-term prognostic significance of total choline-containing phospholipid levels in a well-characterized cohort of 193 men with acute coronary syndromes who were referred for coronary angiography at a Department of Veterans Affairs Medical Center. All patients were followed prospectively for the development of vascular outcomes. After controlling for a variety of baseline variables (including established biomarkers such high-sensitivity C-reactive protein and fibrinogen), plasma phospholipid values (analyzed as a continuous variable) were a strong and independent predictor of each of the individual end points of all-cause mortality (hazard ratio [HR] 0.61, 95% confidence interval [CI] 0.41 to 0.90, p = 0.0126), cardiac mortality (HR 0.49, 95% CI 0.29 to 0.81, p = 0.0057), and myocardial infarction (HR 0.71, 95% CI 0.52 to 0.98, p = 0.0342) when using a Cox proportional-hazards model. In addition, baseline phospholipid values were also an independent predictor of the composite outcome of all-cause mortality, fatal or nonfatal myocardial infarction, or stroke (HR 0.66, 95% CI 0.49 to 0.90, p = 0.0075). In conclusion, these data demonstrate that low baseline levels of total choline-containing phospholipid are a strong and independent predictor of cardiovascular outcomes (including mortality) in patients with acute coronary syndromes.

The Lipid Composition Modulates the Influence of the Bovine Seminal Plasma Protein PDC-109 on Membrane Stability

The bovine seminal plasma protein PDC-109 exerts an essential influence on the sperm cell plasma membrane during capacitation. However, by any mechanism, it has to be ensured that this function of the protein on sperm cells is not initiated too early, that is, upon ejaculation when PDC-109 and sperm cells come into first contact, but rather at later stages of sperm genesis in the female genital tract. To answer the question of whether changes of the bovine sperm lipid composition can modulate the effect of PDC-109 on sperm membranes, we have investigated the influence of PDC-109 on the integrity of (i) differently composed lipid vesicles and of (ii) membranes from human red blood cells and bovine spermatozoa. PDC-109 most effectively disturbed lipid membranes composed of choline-containing phospholipids and in the absence of cholesterol. The impact of the protein on lipid vesicles was attenuated in the presence of cholesterol or of noncholine-containing phospholipids, such as phosphatidylethanolamine or phosphatidylserine. An extraction of cholesterol from lipid or biological membranes using methyl-beta-cyclodextrin caused an increased membrane perturbation by PDC-109. Our results argue for a oppositional effect of PDC-109 during sperm cell genesis. We hypothesize that the lipid composition of ejaculated bull sperm cells allows a binding of PDC-109 without leading to an impairment of the plasma membrane. At later stages of sperm cell genesis upon release of cholesterol from sperm membranes, PDC-109 triggers a destabilization of the cells.