scholarly journals Uptake of lipoproteins by in situ perfused rat ovaries: identification of binding sites for high density lipoproteins.

1983 ◽  
Vol 97 (3) ◽  
pp. 593-606 ◽  
Author(s):  
L G Paavola ◽  
J F Strauss
Keyword(s):  
High Density Lipoprotein ◽  
Density Lipoprotein ◽  
High Density ◽  
Luteal Cell ◽  
High Density Lipoproteins ◽  
Vascular Perfusion ◽  
Electron Microscope Autoradiography ◽  
Luteal Cells ◽  
Cholesteryl Linoleate

We have examined the uptake and distribution of 125I-labeled human high density lipoprotein, apolipoprotein E-free (hHDL3), 125I-rat high density lipoprotein (HDL), and human HDL (hHDL) reconstituted with [3H]cholesteryl linoleate after their in situ vascular perfusion to ovaries of gonadotropin-primed immature rats on days 6-9 post human chorionic gonadotropin (hCG)-injection. Some rats were treated with 4-aminopyrazolopyrimidine to reduce plasma lipoproteins and ovarian cholesteryl ester stores. Perfused ovaries were analyzed biochemically and autoradiographically, and progestin content of the ovarian effluent was quantified. Infusion of ovine luteinizing hormone and hHDL increased ovarian progestin secretion severalfold, indicating that the perfused ovary was functional. After perfusion with HDL reconstituted with [3H]cholesteryl linoleate, radioactive progestin appeared in the effluent; thus, sterol carried by exogenous HDL was converted to steroid. At 37 degrees C, uptake of 125I-hHDL3 was greatest after 15 min of perfusion with label. This was decreased by 80% when the perfusion was carried out at 4 degrees C and by 70-95% when excess unlabeled hHDL, but not human low density lipoprotein (hLDL), was included in the perfusate with 125I-hHDL. Aminopyrazolopyrimidine treatment enhanced 125I-hHDL uptake twofold. After perfusion for 15 min with 125I-hHDL3, radioactivity in the ovary was high for 3-30 min of HDL-free wash, then declined 75% by 30-60 min. With light and electron microscope autoradiography, 125I-hHDL3 was localized to corpora lutea, both along luteal cell surfaces and over their cytoplasm. The plasma membrane grains appeared to be associated with segments that lacked bristle coats. Perfusion with 125I-rat HDL produced a similar pattern of labeling. In ovaries perfused with 125I-BSA, silver grains were concentrated over macrophage-like cells but were sparse over luteal cells. We conclude that the in situ perfused rat ovary takes up 125I-hHDL3 by a temperature-dependent, lipoprotein-specific process, and that this lipoprotein is accumulated by luteal cells.

scholarly journals High-Density Lipoproteins and Cardiovascular Disease: The Good, the Bad and the Future

Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 857
Author(s):  
Josep Julve ◽  
Joan Carles Escolà-Gil
Keyword(s):  
Cardiovascular Disease ◽  
High Density Lipoprotein ◽  
High Density Lipoprotein Cholesterol ◽  
Density Lipoprotein ◽  
Epidemiological Studies ◽  
High Density ◽  
High Density Lipoproteins ◽  
Atherosclerotic Cardiovascular Disease ◽  
Plasma High Density ◽  
Low Levels

Epidemiological studies have shown that low levels of plasma high-density lipoprotein cholesterol (HDL-C) are associated with increased atherosclerotic cardiovascular disease (CVD) [...]

Involvement of high-density lipoprotein in stimulatory effect of hormones supporting function of the bovine corpus luteum.

2003 ◽  
Vol 51 (1) ◽  
pp. 111-120 ◽  
Author(s):  
D. Skarżyński ◽  
J. Młynarczuk ◽  
J. Kotwica
Keyword(s):  
Luteinising Hormone ◽  
Density Lipoprotein ◽  
High Density ◽  
High Density Lipoproteins ◽  
Luteal Cells ◽  
Progesterone Secretion ◽  
Bovine Corpus Luteum ◽  
Progesterone Synthesis ◽  
Deficient Medium ◽  
Intracellular Pathway

The hypothesis that epinephrine (noradrenaline, NA) enhances utilisation of high-density lipoproteins (HDL) by bovine luteal cells and that this process involves phospholipase (PL) C and protein kinase (PK) C intracellular pathway was tested. Luteal cells from days 2-4, 5-10 or 11-17 of the oestrous cycle were pre-incubated for 20h. Subsequently DMEM/Ham's F-12 medium was replaced by fresh medium and the cells were treated for 6 h as follows: In Experiment I with HDL (5-75μg cholesterol per ml), NA, isoprenaline (ISO) or luteinising hormone (LH). In Experiment II cells were incubated for further 24h in deficient medium (without FCS) and next treated as in Experiment I. In Experiment III cells were stimulated with NA, ISO or LH alone and together with HDL. In Experiment IV cells were treated with PLC inhibitor (U-73122) or with PKC inhibitor (staurosporine) or stimulator (phorbol 12-myristrate 13-acetate) and with either NA, insulin or LH. Only luteal cells from days 5-10 of the cycle responded on HDL and β-mimetics (P<0.05). LH stimulated progesterone secretion from the luteal cells during all stages of the cycle (P<0.001). Cells incubated in deficient medium and supplemented with HDL secreted as much progesterone as those stimulated by LH in all stages of the cycle. Beta-mimetics were unable to enhance the stimulatory effect of HDL. Blockade of PLC had no influence on progesterone secretion from cells treated with either NA or LH, but this did impair the stimulatory effect of insulin (P<0.05). Similarly, blockade of PKC by staurosporine impaired (P<0.05) the effect of insulin only but not that observed after LH or NA treatment. We suggest that: (a) noradrenergic stimulation does not enhance utilisation of cholesterol from HDL for progesterone secretion; (b) the fasting of luteal cells seems to activate enzymes responsible for the progesterone synthesis; (c) effect of NA on progesterone secretion from luteal cells does not involve the PLC-PKC pathway.

Determination of high-density lipoprotein phospholipids in serum.

1980 ◽  
Vol 26 (9) ◽  
pp. 1275-1277 ◽  
Author(s):  
Y Yamaguchi
Keyword(s):  
High Density Lipoprotein ◽  
Density Lipoprotein ◽  
Mean Value ◽  
High Density ◽  
High Density Lipoproteins ◽  
Low Density ◽  
Very Low Density Lipoproteins ◽  
Color Development ◽  
The Mean

Abstract I describe a method for measuring high-density lipoprotein phospholipids. Magnesium chloride and dextran sulfate are used to precipitate all low-density and very-low-density lipoproteins. The supernate contains only high-density lipoproteins, the phospholipid concentration of which is determined by an enzymic method. The precision of the method (CV) is 2.35% (10 repeated assays), and the mean value for HDL-phospholipids was 1006 (SD 248) mg/L for 30 apparently healthy subjects. I used electrophoresis and enzymic color development to confirm the presence of HDL-phospholipids. Results are compared with those obtained by an ultracentrifugation method.

scholarly journals Featured Article: Depletion of HDL3 high density lipoprotein and altered functionality of HDL2 in blood from sickle cell patients

2017 ◽  
Vol 242 (12) ◽  
pp. 1244-1253 ◽  
Author(s):  
Eric Soupene ◽  
Sandra K Larkin ◽  
Frans A Kuypers
Keyword(s):  
Sickle Cell Disease ◽  
High Density Lipoprotein ◽  
Sickle Cell ◽  
Acute Phase ◽  
Whole Blood ◽  
Density Lipoprotein ◽  
High Density ◽  
High Density Lipoproteins ◽  
Mrna Levels ◽  
Cell Disease

In sickle cell disease (SCD), alterations of cholesterol metabolism is in part related to abnormal levels and activity of plasma proteins such as lecithin cholesterol acyltransferase (LCAT), and apolipoprotein A-I (ApoA-I). In addition, the size distribution of ApoA-I high density lipoproteins (HDL) differs from normal blood. The ratio of the amount of HDL2 particle relative to the smaller higher density pre-β HDL (HDL3) particle was shifted toward HDL2. This lipoprotein imbalance is exacerbated during acute vaso-occlusive episodes (VOE) as the relative levels of HDL3 decrease. HDL3 deficiency in SCD plasma was found to relate to a slower ApoA-I exchange rate, which suggests an impaired ABCA1-mediated cholesterol efflux in SCD. HDL2 isolated from SCD plasma displayed an antioxidant capacity normally associated with HDL3, providing evidence for a change in function of HDL2 in SCD as compared to HDL2 in normal plasma. Although SCD plasma is depleted in HDL3, this altered capacity of HDL2 could account for the lack of difference in pro-inflammatory HDL levels in SCD as compared to normal. Exposure of human umbilical vein endothelial cells to HDL2 isolated from SCD plasma resulted in higher mRNA levels of the acute phase protein long pentraxin 3 (PTX3) as compared to incubation with HDL2 from control plasma. Addition of the heme-scavenger hemopexin protein prevented increased expression of PTX3 in sickle HDL2-treated cells. These findings suggest that ApoA-I lipoprotein composition and functions are altered in SCD plasma, and that whole blood transfusion may be considered as a blood replacement therapy in SCD. Impact statement Our study adds to the growing evidence that the dysfunctional red blood cell (RBC) in sickle cell disease (SCD) affects the plasma environment, which contributes significantly in the vasculopathy that defines the disease. Remodeling of anti-inflammatory high density lipoprotein (HDL) to pro-inflammatory entities can occur during the acute phase response. SCD plasma is depleted of the pre-β particle (HDL3), which is essential for stimulation of reverse cholesterol from macrophages, and the function of the larger HDL2 particle is altered. These dysfunctions are exacerbated during vaso-occlusive episodes. Interaction of lipoproteins with endothelium increases formation of inflammatory mediators, a process counteracted by the heme-scavenger hemopexin. This links hemolysis to lipoprotein-mediated inflammation in SCD, and hemopexin treatment could be considered. The use of RBC concentrates in transfusion therapy of SCD patients underestimates the importance of the dysfunctional plasma compartment, and transfusion of whole blood or plasma may be warranted.

High-density Lipoprotein Cholesterol: Current Perspective for Clinicians

Angiology ◽  
2009 ◽  
Vol 60 (5) ◽  
pp. 644-649 ◽  
Author(s):  
Thomas F. Whayne
Keyword(s):  
Cardiovascular Risk ◽  
High Density Lipoprotein ◽  
Nicotinic Acid ◽  
Cholesteryl Ester Transfer Protein ◽  
High Density Lipoprotein Cholesterol ◽  
Density Lipoprotein ◽  
High Density ◽  
Lipoprotein Cholesterol ◽  
High Density Lipoproteins ◽  
Transfer Protein

High-density lipoproteins are regarded as “good guys” but not always. Situations involving high-density lipoproteins are discussed and medication results are considered. Clinicians usually consider high-density lipoprotein cholesterol. Nicotinic acid is the best available medication to elevate high-density lipoprotein cholesterol and this appears beneficial for cardiovascular risk. The major problem with nicotinic acid is that many patients do not tolerate the associated flushing. Laropiprant decreases this flushing and has an approval in Europe but not in the United States. The most potent medications for increasing high-density lipoprotein cholesterol are cholesteryl ester transfer protein inhibitors. The initial drug in this class, torcetrapib, was eliminated by excess cardiovascular problems. Two newer cholesteryl ester transfer protein inhibitors, R1658 and anacetrapib, initially appear promising. High-density lipoprotein cholesterol may play an important role in improving cardiovascular risk in the 60% of patients who do not receive cardiovascular mortality/morbidity benefit from low-density lipoproteins reduction by statins.

Fetal and Maternal Lipoprotein Metabolism in Human Pregnancy

1995 ◽  
Vol 88 (3) ◽  
pp. 311-318 ◽  
Author(s):  
Richard H. Neary ◽  
Mark D. Kilby ◽  
Padma Kumpatula ◽  
Francis L. Game ◽  
Deepak Bhatnagar ◽  
...  
Keyword(s):  
Caesarean Section ◽  
High Density Lipoprotein ◽  
Cholesteryl Ester ◽  
Free Cholesterol ◽  
Cholesterol Metabolism ◽  
Density Lipoprotein ◽  
High Density ◽  
High Density Lipoproteins ◽  
Lipoprotein A ◽  
Lipid Enrichment

1. Lipid, apolipoprotein concentration and composition were determined in maternal venous and umbilical arterial and venous blood at delivery by elective Caesarean section in 13 full-term pregnancies and in 25 healthy non-pregnant females. The indications of Caesarean section were a previous Caesarean section or breech presentation. None of the women was in labour and there were no other complications of pregnancy or fetal distress. 2. The objectives of the study were to establish whether the placenta has a role in feto-maternal cholesterol metabolism through either synthesis or transplacental cholesterol flux. The potential for free cholesterol diffusion between mother and fetus and rates of cholesterol esterification and transfer between lipoproteins were determined and related to the differences in composition between fetal and maternal lipoproteins. 3. Pregnant women had raised levels of all lipid and lipoprotein fractions compared with control subjects. The greatest increases were in free cholesterol and triacylglycerol (P < 0.0001). Lipoprotein (a) levels were significantly greater in the pregnant women [112(12.2) mg/l] than in the control women [50 (10.0) mg/l]. 4. The only significant correlation between maternal and fetal lipoprotein concentrations was in lipoprotein (a) levels (r = 0.791, P = 0.002). In both umbilical venous and arterial blood, concentrations of very-low- and low-density lipoproteins, particularly apolipoprotein B, cholesteryl ester and triacylglycerol, were lower than in maternal blood (P < 0.0001), but high-density lipoprotein levels were similar. 5. There was no umbilical arteriovenous differences in lipoprotein concentration or composition. This suggests that cholesterol synthesis or free cholesterol diffusion does not occur in the placenta. The relative concentrations of free cholesterol to phospholipid in maternal and fetal lipoproteins do not indicate the existence of a concentration gradient favouring free cholesterol diffusion across the placenta. 6. The esterification of free cholesterol was significantly reduced in maternal [17.7 (2.4) μmol h−1 l−1, P < 0.001] and fetal [6.7 (3.5) μmol h−1 l−1, P < 0.0001] compared with control [40.9 (13.2) μmol h−1 l−1] blood. 7. In fetal compared with maternal high-density lipoproteins the ratios cholesteryl ester/apoliproprotein A-I [0.84 (0.35) versus 0.40 (0.05), P < 0.01] and phospholipid/apolipoprotein A-I [1.66 (0.14) versus 0.58 (0.10), P < 0.0001] indicated lipid enrichment of these particles in the fetus. 8. Lipid enrichment of high-density lipoprotein is due in part to a marked reduction in transfer of cholesteryl ester in the fetus [1.0 (0.6) μmol h−1 l−1] compared with maternal [6.15 (1.3) μmol h−1 l−1, P = 0.004] and control [17.3 (7.2) μmol h−1 l−1, P < 0.0001] blood. 9. In conclusion, there was no evidence for involvement of the placenta in cholesterol metabolism during pregnancy. In fetal life high-density lipoproteins are lipid rich, partly because of a reduction in transfer of esterified cholesterol to other particles. Maternal and fetal lipoprotein levels are not correlated, although the results suggested that lipoprotein (a) levels may be related.

Plasma-derived and synthetic high-density lipoprotein inhibit tissue factor in endothelial cells and monocytes

2016 ◽  
Vol 473 (2) ◽  
pp. 211-219 ◽  
Author(s):  
Alice Ossoli ◽  
Alan T. Remaley ◽  
Boris Vaisman ◽  
Laura Calabresi ◽  
Monica Gomaraschi
Keyword(s):  
Endothelial Cells ◽  
High Density Lipoprotein ◽  
Tissue Factor ◽  
Density Lipoprotein ◽  
High Density ◽  
Coagulation Cascade ◽  
High Density Lipoproteins

Atheroprotection mediated by high-density lipoproteins could also be related to their ability to inhibit the expression of tissue factor, the main activator of the coagulation cascade, in endothelial cells and in monocytes.

scholarly journals Selective evaluation of high density lipoprotein from mouse small intestine by an in situ perfusion technique

2014 ◽  
Vol 55 (5) ◽  
pp. 905-918 ◽  
Author(s):  
Satoshi Yamaguchi ◽  
Bo Zhang ◽  
Takeshi Tomonaga ◽  
Utako Seino ◽  
Akiko Kanagawa ◽  
...  
Keyword(s):  
Small Intestine ◽  
High Density Lipoprotein ◽  
Density Lipoprotein ◽  
High Density ◽  
Perfusion Technique ◽  
In Situ Perfusion ◽  
Mouse Small Intestine
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