Differential Effects of Reconstituted High-density Lipoprotein on Coagulation, Fibrinolysis and Platelet Activation during Human Endotoxemia

SummaryHigh-density lipoproteins (HDL) can bind and neutralize lipopoly- saccharides (LPS) in vitro and in vivo. HDL can also affect fibrinolytic activity and can directly influence platelet function by reducing platelet aggregation. In this study, the effects of reconstituted HDL (rHDL) on LPS-induced coagulation, fibrinolysis and platelet activation in humans were investigated. In a double-blind, randomized, placebo-controlled, cross-over study, eight healthy male volunteers were injected with LPS (4 ng/kg) on two occasions, once in conjunction with rHDL (40 mg/kg, given as a 4 h infusion starting 3.5 h prior to LPS injection), and once in conjunction with placebo. rHDL significantly reduced LPS-induced activation of coagulation (plasma levels of prothrombin fragment F1+2) and fibrinolysis (plasma levels of tissue type plasminogen activator antigen, t-PA). No effect was observed on LPS-induced inhibition of the fibrinolytic pathway (PAI-1) or on the transient thrombocytopenia elicited by LPS. Furthermore, rHDL treatment significantly enhanced the inhibition of collagen-stimulated inhibition of platelet aggregation during endotoxemia, but had no such effect on arachido- nate-stimulated platelet aggregation. rHDL treatment per se also reduced collagen-induced platelet aggregation. These results indicate that rHDL modifies the procoagulant state associated with endotoxemia.

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Evidence for the role of high density lipoproteins in mediating the antioxidant effect of estrogens

Acta Endocrinologica ◽

10.1530/eje.0.1420079 ◽

2000 ◽

pp. 79-83 ◽

Cited By ~ 15

Author(s):

W Abplanalp ◽

MD Scheiber ◽

K Moon ◽

B Kessel ◽

JH Liu ◽

...

Keyword(s):

Density Lipoprotein ◽

Antioxidant Effect ◽

High Density ◽

In Vivo Studies ◽

Ldl Oxidation ◽

High Density Lipoproteins ◽

Oh Groups

Estrogens possess strong antioxidant effects in vitro, but in vivo studies in humans have yielded conflicting results. Little is known regarding factors that mediate the antioxidant effect of estrogens in vivo. In this study the potential role of high density lipoprotein (HDL) was examined. The antioxidant effect of estradiol-17beta (E2) added to low density lipoprotein (LDL) was lost after dialysis. In contrast, the antioxidant effect of E2 added to HDL was conserved after dialysis, suggesting that E2 was bound to HDL. Binding of E2 to LDL increased after esterification (especially to long chain fatty acids). In the presence of HDL, an increased amount of E2 was transferred to LDL. E2-17 ester was as potent as E2 in preventing LDL oxidation in vitro, but 3,17-diesters were not as effective (E2=E2-17 ester>E2-3 ester>E2-3,17 diester). This was also supported by experiments which showed that estrogens with masked 3-OH groups were not effective as antioxidants. These studies provide evidence that HDL could facilitate the antioxidant effect of E2 through initial association, esterification and eventual transfer of E2 esters to LDL. Therefore it is critical that HDL peroxidation parameters be evaluated in subjects receiving estrogen replacement therapy.

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Uptake of high density lipoproteins by rat ovaries in vivo and dispersed ovarian cells in vitro. Direct correlation of high density lipoprotein uptake with steroidogenic activity

Journal of Steroid Biochemistry ◽

10.1016/0022-4731(82)90074-7 ◽

1982 ◽

Vol 16 (4) ◽

pp. 525-531 ◽

Cited By ~ 21

Author(s):

Jerome F. Strauss ◽

Leslie C. MacGregor ◽

John T. Gwynne

Keyword(s):

High Density Lipoprotein ◽

Density Lipoprotein ◽

High Density ◽

High Density Lipoproteins ◽

Ovarian Cells ◽

Lipoprotein Uptake

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Transfer and Enzyme-Mediated Metabolism of Oxidized Phosphatidylcholine and Lysophosphatidylcholine between Low- and High-Density Lipoproteins

Antioxidants ◽

10.3390/antiox9111045 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1045

Author(s):

Naoko Sawada ◽

Takashi Obama ◽

Mirei Mizuno ◽

Kiyoshi Fukuhara ◽

Sanju Iwamoto ◽

...

Keyword(s):

Cholesterol Acyltransferase ◽

Density Lipoprotein ◽

High Density ◽

Short Chain ◽

High Density Lipoproteins ◽

Dependent Manner ◽

Atheromatous Plaques ◽

Oxidized Phosphatidylcholine

Oxidized low-density lipoprotein (oxLDL) and oxidized high-density lipoprotein (oxHDL), known as risk factors for cardiovascular disease, have been observed in plasma and atheromatous plaques. In a previous study, the content of oxidized phosphatidylcholine (oxPC) and lysophosphatidylcholine (lysoPC) species stayed constant in isolated in vivo oxLDL but increased in copper-induced oxLDL in vitro. In this study, we prepared synthetic deuterium-labeled 1-palmitoyl lysoPC and palmitoyl-glutaroyl PC (PGPC), a short chain-oxPC to elucidate the metabolic fate of oxPC and lysoPC in oxLDL in the presence of HDL. When LDL preloaded with d13-lysoPC was mixed with HDL, d13-lysoPC was recovered in both the LDL and HDL fractions equally. d13-LysoPC decreased by 50% after 4 h of incubation, while d13-PC increased in both fractions. Diacyl-PC production was abolished by an inhibitor of lecithin-cholesterol acyltransferase (LCAT). When d13-PGPC-preloaded LDL was incubated with HDL, d13-PGPC was transferred to HDL in a dose-dependent manner when both LCAT and lipoprotein-associated phospholipase A2 (Lp-PLA2) were inhibited. Lp-PLA2 in both HDL and LDL was responsible for the hydrolysis of d13-PGPC. These results suggest that short chain-oxPC and lysoPC can transfer between lipoproteins quickly and can be enzymatically converted from oxPC to lysoPC and from lysoPC to diacyl-PC in the presence of HDL.

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High-Density Lipoproteins and Serum Amyloid A (SAA)

Current Atherosclerosis Reports ◽

10.1007/s11883-020-00901-4 ◽

2021 ◽

Vol 23 (2) ◽

Author(s):

Nancy R. Webb

Keyword(s):

Serum Amyloid A ◽

Inflammatory Responses ◽

Inflammatory Diseases ◽

Density Lipoprotein ◽

High Density ◽

Serum Amyloid ◽

High Density Lipoproteins ◽

Amyloid A

Abstract Purpose of Review Serum amyloid A (SAA) is a highly sensitive acute phase reactant that has been linked to a number of chronic inflammatory diseases. During a systemic inflammatory response, liver-derived SAA is primarily found on high-density lipoprotein (HDL). The purpose of this review is to discuss recent literature addressing the pathophysiological functions of SAA and the significance of its association with HDL. Recent Findings Studies in gene-targeted mice establish that SAA contributes to atherosclerosis and some metastatic cancers. Accumulating evidence indicates that the lipidation state of SAA profoundly affects its bioactivities, with lipid-poor, but not HDL-associated, SAA capable of inducing inflammatory responses in vitro and in vivo. Factors that modulate the equilibrium between lipid-free and HDL-associated SAA have been identified. Summary HDL may serve to limit SAA’s bioactivities in vivo. Understanding the factors leading to the release of systemic SAA from HDL may provide insights into chronic disease mechanisms.

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Antiinflammatory effects of reconstituted high-density lipoprotein during human endotoxemia.

Journal of Experimental Medicine ◽

10.1084/jem.184.5.1601 ◽

1996 ◽

Vol 184 (5) ◽

pp. 1601-1608 ◽

Cited By ~ 262

Author(s):

D Pajkrt ◽

J E Doran ◽

F Koster ◽

P G Lerch ◽

B Arnet ◽

...

Keyword(s):

High Density Lipoprotein ◽

Density Lipoprotein ◽

High Density ◽

Double Blind ◽

Endotoxin Challenge ◽

Biologically Relevant ◽

Cytokine Inhibitors ◽

Enhanced Expression

High-density lipoprotein (HDL) has been found to neutralize LPS activity in vitro and in animals in vivo. We sought to determine the effects of reconstituted HDL (rHDL) on LPS responsiveness in humans in a double-blind, randomized, placebo-controlled, cross-over study. rHDL, given as a 4-h infusion at 40 mg/kg starting 3.5 h before endotoxin challenge (4 ng/kg), reduced flu-like symptoms during endotoxemia, but did not influence the febrile response. rHDL potently reduced the endotoxin-induced release of TNF, IL-6, and IL-8, while only modestly attenuating the secretion of proinflammatory cytokine inhibitors IL-1ra, soluble TNF receptors and IL-10. In addition, rHDL attenuated LPS-induced changes in leukocyte counts and the enhanced expression of CD11b/CD18 on granulocytes. Importantly, rHDL infusion per se, before LPS administration, was associated with a downregulation of CD14, the main LPS receptor, on monocytes. This effect was biologically relevant, since monocytes isolated from rHDL-treated whole blood showed reduced expression of CD14 and diminished TNF production upon stimulation with LPS. These results suggest that rHDL may inhibit LPS effects in humans in vivo not only by binding and neutralizing LPS but also by reducing CD14 expression on monocytes.

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Binding of thyroxine and 3,5,3'-triiodothyronine to trout plasma lipoproteins

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1992.262.5.e712 ◽

1992 ◽

Vol 262 (5) ◽

pp. E712-E720 ◽

Cited By ~ 4

Author(s):

P. J. Babin

Keyword(s):

Nutritional Status ◽

Binding Sites ◽

Density Lipoprotein ◽

High Density ◽

Plasma Lipoproteins ◽

High Density Lipoproteins ◽

Minor Role ◽

Very Low Density Lipoproteins

The plasma vectors of thyroid hormones (TH) in trout have been characterized. Plasma components were separated by density gradient ultracentrifugation after first labeling binding sites with trace levels of radioactive hormones, both in vivo and in vitro. Lipoproteins play only a minor role in humans but are major carriers of thyroxine (T4) and 3,5,3'-triiodothyronine (T3) in trout plasma. More than 67% of T4 and 89% of T3 were bound to lipoproteins (density less than 1.210 g/ml), predominantly to high-density lipoproteins (HDL), regardless of the nutritional status of the animals. The percentage of hormone bound to very-low-density lipoproteins, on the other hand, was proportional to their concentration and thus to nutritional status. T3 and T4 could also bind to vitellogenin, a very-high-density lipoprotein, which could transfer TH to the yolk of oocytes. Homologous ligand displacement indicated that T3 could bind to at least two classes of saturable sites in the plasma. In addition, plasma HDL were the major binding sites with low affinity (1.7 +/- 0.4 x 10(5) M-1) but with high capacity (3.1 +/- 0.3 x 10(-5) M). In conclusion, these results show that lipoproteins are the principal binding sites of TH in trout plasma.

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High density lipoproteins mediate in vivo protection against staphylococcal phenol-soluble modulins

Scientific Reports ◽

10.1038/s41598-021-94651-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Josefien W. Hommes ◽

Rachel M. Kratofil ◽

Sigrid Wahlen ◽

Carla J. C. de Haas ◽

Reeni B. Hildebrand ◽

...

Keyword(s):

Density Lipoprotein ◽

Bloodstream Infections ◽

Hdl Cholesterol ◽

High Density ◽

High Density Lipoproteins ◽

Dependent Manner ◽

Biological Functions ◽

Healthy Humans

AbstractStaphylococcus aureus virulence has been associated with the production of phenol-soluble modulins (PSMs). These PSMs have distinct virulence functions and are known to activate, attract and lyse neutrophils. These PSM-associated biological functions are inhibited by lipoproteins in vitro. We set out to address whether lipoproteins neutralize staphylococcal PSM-associated virulence in experimental animal models. Serum from both LCAT an ABCA1 knockout mice strains which are characterised by near absence of high-density lipoprotein (HDL) levels, was shown to fail to protect against PSM-induced neutrophil activation and lysis in vitro. Importantly, PSM-induced peritonitis in LCAT−/− mice resulted in increased lysis of resident peritoneal macrophages and enhanced neutrophil recruitment into the peritoneal cavity. Notably, LCAT−/− mice were more likely to succumb to staphylococcal bloodstream infections in a PSM-dependent manner. Plasma from homozygous carriers of ABCA1 variants characterized by very low HDL-cholesterol levels, was found to be less protective against PSM-mediated biological functions compared to healthy humans. Therefore, we conclude that lipoproteins present in blood can protect against staphylococcal PSMs, the key virulence factor of community-associated methicillin resistant S. aureus.

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The d-Enantiomer Form of Indobufen Totally Accounts for the Anti-Cyclooxygenase and Antiplatelet Activity Ex Vivo and for the Increase in Bleeding Time by Indobufen in Man

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648422 ◽

1992 ◽

Vol 67 (02) ◽

pp. 258-263 ◽

Cited By ~ 12

Author(s):

Raffaele De Caterina ◽

Rosa Sicari ◽

An Yan ◽

Walter Bernini ◽

Daniela Giannessi ◽

...

Keyword(s):

Arachidonic Acid ◽

Platelet Aggregation ◽

Plasma Levels ◽

Bleeding Time ◽

Ex Vivo ◽

Random Sequence ◽

Antiplatelet Agent ◽

Antiplatelet Drug ◽

Double Blind

SummaryIndobufen is an antiplatelet drug able to inhibit thromboxane production and cyclooxygenase-dependent platelet aggregation by a reversible inhibition of cyclooxygenase. Indobufen exists in two enantiomeric forms, of which only d-indobufen is active in vitro in inhibiting cyclooxygenase. In order to verify that also inhibition of platelet function is totally accounted for by d-indobufen, ten patients with proven coronary artery disease (8 male, 2 female, age, mean ± S.D., 58.7 ± 7.5 years) were given, in random sequence, both 100 mg d-indobufen and 200 mg dl-indobufen as single administrations in a double-blind crossover design study with a washout period between treatments of 72 h. In all patients thromboxane (TX) B2 generation after spontaneous clotting (at 0, 1, 2, 4, 6, 8, 12, 24 h), drug plasma levels (at the same times), platelet aggregation in response to ADP, adrenaline, arachidonic acid, collagen, PAF, and bleeding time (at 0, 2, 12 h) were evaluated after each treatment. Both treatments determined peak inhibition of TXB2 production at 2 h from administration, with no statistical difference between the two treatments (97 ±3% for both treatments). At 12 h inhibition was 87 ± 6% for d-indobufen and 88 ± 6% for dl-indobufen (p = NS). Inhibition of TXB2 production correlated significantly with plasma levels of the drugs. Maximum inhibitory effect on aggregation was seen in response to collagen 1.5 pg/ml (63 ± 44% for d-indobufen and 81 ± 22% for dl-indobufen) and arachidonic acid 0.5-2 mM (78 ± 34% for d-indobufen and 88 ± 24% for dl-indobufen) at 2 h after each administration. An effect of both treatments on platelet aggregation after 12 h was present only for adrenaline 2 μM (55 ± 41% for d-indobufen and 37 ± 54% for dl-indobufen), collagen 1.5 pg/ml (69 ± 30% for d-indobufen and 51 ± 61% for dl-indobufen), arachidonic acid 0.5-2 mM (56 ± 48% for d-indobufen and 35 ± 49% for dl-indobufen). The extent of inhibition of TX production and the extent of residual platelet aggregation were never significantly different between treatments. Bleeding time prolongation was similar in the two treatment groups without showing a pronounced and long lasting effect (from 7.0 ± 2.0 min to 10.0 ± 3.0 min at 2 h and 8.0 ± 2.0 min at 12 h for d-indobufen; from 6.0 ±1.0 min to 8.5 ± 2.0 min at 2 h and 8.0 ± 1.0 min at 12 h for dl-indobufen). These results demonstrate that the biological activity of dl-indobufen as an antiplatelet agent in vivo is totally accounted for by d-indobufen.

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Effects of Ticlopidine of Platelet Function in Men with Stable Angina Pectoris

Thrombosis and Haemostasis ◽

10.1055/s-0038-1660138 ◽

1985 ◽

Vol 54 (04) ◽

pp. 808-812 ◽

Cited By ~ 7

Author(s):

Ulf Berglund ◽

Henning von Schenck ◽

Lars Wallentin

Keyword(s):

Platelet Aggregation ◽

Angina Pectoris ◽

Platelet Function ◽

Plasma Levels ◽

Platelet Reactivity ◽

Inhibitory Effect ◽

Controlled Study ◽

Double Blind ◽

Platelet Factor

SummaryThe effects of ticlopidine (T) (500 mg daily) on platelet function were investigated in a double-blind placebo-controlled study in 38 middle-aged men with stable incapacitating angina pectoris. The in vitro platelet reactivity to aggregating agents, the platelet sensitivity to prostacyclin and the plasma levels of platelet specific proteins and fibrinogen were determined before and after 4 and 8 weeks of treatment. T exerted a potent inhibitory effect on ADP- and collagen-induced platelet aggregation. The effect of T was proportional to the pretreatment reactivity to ADP and collagen. The inhibitory effect of T on the epinephrine response was less pronounced. The plasma levels of beta-thromboglobulin, platelet factor 4 and fibrinogen were not influenced by T. The platelet inhibition of prostacyclin was potentiated by T, and it was demonstrated that T and prostacyclin had synergistic inhibitory effects on platelet aggregation.

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