scholarly journals Esterification of 4β-hydroxycholesterol and other oxysterols in human plasma occurs independently of LCAT

2020 ◽  
Vol 61 (9) ◽  
pp. 1287-1299 ◽  
Author(s):  
Daisuke Yamamuro ◽  
Hisataka Yamazaki ◽  
Jun-ichi Osuga ◽  
Kenta Okada ◽  
Tetsuji Wakabayashi ◽  
...  

The acyltransferase LCAT mediates FA esterification of plasma cholesterol. In vitro studies have shown that LCAT also FA-esterifies several oxysterols, but in vivo evidence is lacking. Here, we measured both free and FA-esterified forms of sterols in 206 healthy volunteers and 8 individuals with genetic LCAT deficiency, including familial LCAT deficiency (FLD) and fish-eye disease (FED). In the healthy volunteers, the mean values of the ester-to-total molar ratios of the following sterols varied: 4β-hydroxycholesterol (4βHC), 0.38; 5,6α-epoxycholesterol (5,6αEC), 0.46; 5,6β-epoxycholesterol (5,6βEC), 0.51; cholesterol, 0.70; cholestane-3β,5α,6β-triol (CT), 0.70; 7-ketocholesterol (7KC), 0.75; 24S-hydroxycholesterol (24SHC), 0.80; 25-hydroxycholesterol (25HC), 0.81; 27-hydroxycholesterol (27HC), 0.86; and 7α-hydroxycholesterol (7αHC), 0.89. In the individuals with LCAT deficiency, the plasma levels of the FA-esterified forms of cholesterol, 5,6αEC, 5,6βEC, CT, 7αHC, 7KC, 24SHC, 25HC, and 27HC, were significantly lower than those in the healthy volunteers. The individuals with FLD had significantly lower FA-esterified forms of 7αHC, 24SHC, and 27HC than those with FED. It is of note that, even in the three FLD individuals with negligible plasma cholesteryl ester, substantial amounts of the FA-esterified forms of 4βHC, 5,6αEC, 7αHC, 7KC, and 27HC were present. We conclude that LCAT has a major role in the FA esterification of many plasma oxysterols but contributes little to the FA esterification of 4βHC. Substantial FA esterification of 4βHC, 5,6αEC, 7αHC, 7KC, and 27HC is independent of LCAT.

2002 ◽  
Vol 46 (5) ◽  
pp. 1510-1515 ◽  
Author(s):  
S. Gupta ◽  
M. M. Thapar ◽  
W. H. Wernsdorfer ◽  
A. Björkman

ABSTRACT The interactions of artemisinin with atovaquone, quinine, and mefloquine were investigated in three Plasmodium falciparum strains (strains F-32, FCR-3, and K-1) by an in vitro culture assay. The parasites were cultured for 48 h in the presence of different concentrations and proportions of two drugs at a time in a checkerboard design. The response parameters were determined, and the sums of the fractional inhibitory concentrations (ΣFICs) of the drug combinations were calculated for different degrees of inhibition (50% effective concentration [EC50], EC90, and EC99). Within therapeutically relevant molar ratios (19 to 200), the combination of quinine and artemisinin showed mean ΣFICs of 1.71 at the EC50, 0.36 at the EC90, and 0.13 at the EC99, indicating increasing synergism. Within the range of molar ratios of 4.3 to 50, the combination of mefloquine and artemisinin yielded mean ΣFCIs of 0.93, 0.44, and 0.31 at the EC50, EC90, and EC99, respectively, indicating synergism. The atovaquone combination showed additive activity to synergism at atovaquone/artemisinin proportions considered relevant to the in vivo situation, i.e., between 4.3 and 200, with the mean ΣFICs decreasing from 1.34 at the EC50 to 0.85 and 0.23 at the EC90 and EC99, respectively. Interstrain differences in the degree of drug interaction were seen with the three strains for all combinations. Synergism was most consistent with quinine.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Furong Qiu ◽  
Jian Jiang ◽  
Yueming Ma ◽  
Guangji Wang ◽  
Chenglu Gao ◽  
...  

The aim of this study was to investigate the effect of single- and multidose administration of the ethanol extract of danshen on in vivo CYP3A activity in healthy volunteers. A sequential, open-label, and three-period pharmacokinetic interaction study design was used based on 12 healthy male individuals. The plasma concentrations of midazolam and its metabolite 1-hydroxymidazolam were measured. Treatment with single dose of the extract caused the meanCmaxof midazolam to increase by 87% compared with control. After 10 days of the danshen extract intake, the mean AUC0–12,Cmax, andt1/2of midazolam were decreased by 79.9%, 66.6%, and 43.8%, respectively. The mean clearance of midazolam was increased by 501.6% compared with control. The in vitro study showed that dihydrotanshinone I in the extract could inhibit CYP3A, while tanshinone IIA and cryptotanshinone could induce CYP3A. In conclusion, a single-dose administration of the danshen extract can inhibit intestinal CYP3A, but multidose administration can induce intestinal and hepatic CYP3A.


1983 ◽  
Vol 100 (1) ◽  
pp. 127-131 ◽  
Author(s):  
P. D. Penning ◽  
R. H. Johnson

SUMMARYConcentrations of potentially indigestible cellulose (PIC) and acid insoluble ash (AIA) were determined in samples of feed and faeces in a study to determine their value as internal markers. PIC and AIA were then used to predict the organic-matter digestibilities (OMD) of samples of perennial ryegrass (Lolium perenne) and lucerne (Medicago sativa)of known OMD which had been determined using wether sheep. The mean values for OMD (%) measured in vivo were 67·2 and 62·8 for ryegrass and 58·0 and 55·8 for lucerne at intakes of 15 and 25 g D.M./kg live weight, respectively.The in vitro digestibility technique, using rumen liquor, gave OMD values of 69·5 and 57·4 for ryegrass and lucerne which are in close agreement with the in vivo values at the lower level of intake.The mean differences between OMD measured in vivo and that estimated using PIC were: -1·1 (± 0·65) and -1·6 (± 0·46) percentage units for ryegrass and lucerne respectively, and using AIA were: -1·4 (± 0·57) and -3·5 (± 1·61).For the two feeds tested, OMD was predicted more precisely by PIC than by AIA or the in vitro digestibility technique. However, the PIC technique required the use of rumen-fistulated animals and 10 days to digest samples of faeces; this may make the technique impractical if large numbers of determinations of PIC are required.


2012 ◽  
Vol 41 (4) ◽  
pp. 914-922 ◽  
Author(s):  
Maurício Hoshino da Costa Barros ◽  
Hugo Hideki Shiomi ◽  
Lincoln da Silva Amorim ◽  
Simone Eliza Facioni Guimarães ◽  
Paulo Sávio Lopes ◽  
...  

The objective of this study was to verify the effect of three protocols of cryopreservation on the sperm viability post-thawing of swine from the Piau breed (Sus scrofa), by means of evaluation assays in vitro and in vivo. Twenty-two ejaculates of 5 adult males of the Piau breed trough the gloved-hand method. In order to verify the sperm viability of the raw semen and post-thawing, the following traits were evaluated: sperm motility and vigor, hypoosmotic test, supra-vital color test and percentage of normal acrosomes. To freezing, the ejaculates were fractioned and submitted in: method 1, method of freezing recommended by Fürst et al. (2005), modified according to media extender; method 2, recommended by Fürst et al. (2005), modified according to the cooling curve; and method 3, recommended by Ohata et al. (2001). To test the in vivo fertility of the frozen/thawed semen, 23 intra-uterine (post-cervical) inseminations were performed in 14 females of the Piau breed, with semen from method 3. The mean values obtained with the use of methods 1 and 2 and post-thawing were inferior to those obtained with method 3. Four adult sows got pregnant (28.6% fertility rate). The freezing method recommended by Ohata et al. (2001), with balance period of 90 minutes at 22-26 ºC, enables higher results of in vitro sperm viability in comparison with the two other methods. The absence of balance period of method 1 and the cooling curve utilized in protocol 2 affect negatively the parameters of sperm viability evaluated in the present study. In spite of the satisfactory results in vitro for the freezing of semen with the utilization of method 3, it presents low fertility rate (28.6%).


1993 ◽  
Vol 70 (04) ◽  
pp. 676-680 ◽  
Author(s):  
H F Kotzé ◽  
V van Wyk ◽  
P N Badenhorst ◽  
A du P Heyns ◽  
J P Roodt ◽  
...  

SummaryPlatelets were isolated from blood of baboons and treated with neuraminidase to remove platelet membrane sialic acid, a process which artificially ages the platelets. The platelets were then labelled with 111In and their mean life span, in vivo distribution and sites of Sequestration were measured. The effect of removal of sialic acid on the attachment of immunoglobulin to platelets were investigated and related to the Sequestration of the platelets by the spleen, liver, and bone marrow. Removal of sialic acid by neuraminidase did not affect the aggregation of platelets by agonists in vitro, nor their sites of Sequestration. The removal of 0.51 (median, range 0.01 to 2.10) nmol sialic acid/108 platelets shortened their life span by 75 h (median, range 0 to 132) h (n = 19, p <0.001), and there was an exponential correlation between the shortening of the mean platelet life span and the amount of sialic acid removed. The increase in platelet-associated IgG was 0.112 (median, range 0.007 to 0.309) fg/platelet (n = 25, p <0.001) after 0.79 (median, range 0.00 to 6.70) nmol sialic acid/108 platelets was removed (p <0.001). There was an exponential correlation between the shortening of mean platelet life span after the removal of sialic acid and the increase in platelet-associated IgG. The results suggest that platelet membrane sialic acid influences ageing of circulating platelets, and that the loss of sialic acid may have exposed a senescent cell antigen that binds IgG on the platelet membrane. The antibody-antigen complex may then provide a signal to the macrophages that the platelet is old, and can be phagocytosed and destroyed.


2009 ◽  
Vol 32 (6S) ◽  
pp. 3
Author(s):  
A Baass ◽  
H Wassef ◽  
M Tremblay ◽  
L Bernier ◽  
R Dufour ◽  
...  

Introduction: LCAT (lecithin:cholesterol acyltransferase ) is an enzyme which plays an essential role in cholesterol esterification and reverse cholesterol transport. Familial LCAT deficiency (FLD) is a disease characterized by a defect in LCAT resulting in extremely low HDL-C, premature corneal opacities, anemia as well as proteinuria and renal failure. Method: We have identified two brothers presenting characteristics of familial LCAT deficiency. We sequenced the LCAT gene, measured the lipid profile as well as the LCAT activity in 15 members of this kindred. We also characterized the plasma lipoproteins by agarose gel electrophoresis and size exclusion chromatography and sequenced several candidate genes related to dysbetalipoproteinemia in this family. Results: We have identified the first French Canadian kindred with familial LCAT deficiency. Two brothers affected by FLD, were homozygous for a novel LCAT mutation. This c.102delG mutation occurs at the codon for His35 causing a frameshift that stops transcription at codon 61 abolishing LCAT enzymatic activity both in vivo and in vitro. It has a dramatic effect on the lipoprotein profile, with an important reduction of HDL-C in both heterozygotes (22%) and homozygotes (88%) and a significant decrease in LDL-C in heterozygotes (35%) as well as homozygotes (58%). Furthermore, the lipoprotein profile differed markedly between the two affected brothers who had different APOE genotypes. We propose that APOE could be an important modifier gene explaining heterogeneity in lipoprotein profiles observed among FLD patients. Our results suggest that a LCAT-/- genotype associated with an APOE ?2 allele could be a novel mechanism leading to dysbetalipoproteinemia.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lena Dalal ◽  
Abdul Wahab Allaf ◽  
Hind El-Zein

AbstractSelf-nanoemulsifying drug delivery systems (SNEDDS) were used to enhance the dissolution rate of furosemide as a model for class IV drugs and the system was solidified into liquisolid tablets. SNEDDS of furosemide contained 10% Castor oil, 60% Cremophor EL, and 30% PEG 400. The mean droplets size was 17.9 ± 4.5 nm. The theoretical model was used to calculate the amounts of the carrier (Avicel PH101) and coating materials (Aerosil 200) to prepare liquisolid powder. Carrier/coating materials ratio of 5/1 was used and Ludipress was added to the solid system, thus tablets with hardness of 45 ± 2 N were obtained. Liquisolid tablets showed 2-folds increase in drug release as compared to the generic tablets after 60 min in HCl 0.1 N using USP apparatus-II. Furosemide loaded SNEDDS tablets have great prospects for further in vivo studies, and the theoretical model is useful for calculating the adequate amounts of adsorbents required to solidify these systems.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2574
Author(s):  
Lahcen Hssaini ◽  
Francisca Hernandez ◽  
Manuel Viuda-Martos ◽  
Jamal Charafi ◽  
Rachid Razouk ◽  
...  

In the present study, chromatic coordinates, phenolic acids, flavonoids and antioxidant capacity assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate (ABTS) and lipid peroxidation inhibition capacity (LPIC) essays and their relative IC50 were investigated in 25 fig cultivars growing in Morocco. The aims of this study were to determine (i) the variation in these compounds among light and dark-colored cultivars, (ii) their partitioning between fruit peel and pulp and (iii) to display network connections among these variables. Twelve phenolic compounds (PCs) were isolated in peel extract versus eight in pulp samples. Anthocyanins, mainly cyanidin-3,5-diglucoside and cyanidin-3-O-rutinoside, were the predominant compounds in peels, where the mean concentrations were 75.90 ± 18.76 and 77.97 ± 18.95 µg/g dw, respectively. On the other hand, (−)-epicatechin and cyanidin-3-O-rutinoside were the major compounds in the pulp extracts, where the mean values were 5.23 ± 4.03 and 9.01 ± 5.67 µg/g dw, respectively. A two-dimensional hierarchically clustered heatmap was applied to the dataset to explore correlations in the dataset and similarities between cultivars, without dimensionality reduction. Results showed that anthocyanins, particularly pelargonidin-3-O-rutinoside, cyanidin-3,5-diglucoside and cyanidin-3-O-rutinoside, were the main contributors to the peels’ free radical scavenging capacity. This capacity was particularly higher in the peel of dark-colored figs compared to the fruit pulp. The local cultivar “INRA 1301” showed the most promising phenolic profile due to its very high levels of almost all detected PCs, especially (−)-epicatechin, quercetin-3-O-rutinoside, quercetin-3-O-glucoside, cyanidine-3,5-diglucoside, cyanidine-3-O-rutinoside and pelargonidin-3-O-rutinoside (54.66, 141.08, 35.48, 494.08, 478.66, 12.56 µg/g dw, respectively). Having the darkest figs in the collection (L* = 25.72, c* = 22.09 and h° = 20.99), this cultivar has also combined promising IC50 values, which were of 19.85, 40.58 and 124.78 µg/mL for DPPH, ABTS and LPIC essays, respectively.


Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3602
Author(s):  
Elena Genova ◽  
Maura Apollonio ◽  
Giuliana Decorti ◽  
Alessandra Tesser ◽  
Alberto Tommasini ◽  
...  

Interferonopathies are rare genetic conditions defined by systemic inflammatory episodes caused by innate immune system activation in the absence of pathogens. Currently, no targeted drugs are authorized for clinical use in these diseases. In this work, we studied the contribution of sulforaphane (SFN), a cruciferous-derived bioactive molecule, in the modulation of interferon-driven inflammation in an immortalized human hepatocytes (IHH) line and in two healthy volunteers, focusing on STING, a key-component player in interferon pathway, interferon signature modulation, and GSTM1 expression and genotype, which contributes to SFN metabolism and excretion. In vitro, SFN exposure reduced STING expression as well as interferon signature in the presence of the pro-inflammatory stimulus cGAMP (cGAMP 3 h vs. SFN+cGAMP 3 h p value < 0.0001; cGAMP 6 h vs. SFN+cGAMP 6 h p < 0.001, one way ANOVA), restoring STING expression to the level of unstimulated cells. In preliminary experiments on healthy volunteers, no appreciable variations in interferon signature were identified after SFN assumption, while only in one of them, presenting the GSTM1 wild type genotype related to reduced SFN excretion, could a downregulation of STING be recorded. This study confirmed that SFN inhibits STING-mediated inflammation and interferon-stimulated genes expression in vitro. However, only a trend towards the downregulation of STING could be reproduced in vivo. Results obtained have to be confirmed in a larger group of healthy individuals and in patients with type I interferonopathies to define if the assumption of SFN could be useful as supportive therapy.


2021 ◽  
Vol 14 (4) ◽  
pp. 294
Author(s):  
Eric G. Romanowski ◽  
Islam T. M. Hussein ◽  
Steven C. Cardinale ◽  
Michelle M. Butler ◽  
Lucas R. Morin ◽  
...  

Presently, there is no FDA- or EMA-approved antiviral for the treatment of human adenovirus (HAdV) ocular infections. This study determined the antiviral activity of filociclovir (FCV) against ocular HAdV isolates in vitro and in the Ad5/NZW rabbit ocular model. The 50% effective concentrations (EC50) of FCV and cidofovir (CDV) were determined for several ocular HAdV types using standard plaque reduction assays. Rabbits were topically inoculated in both eyes with HAdV5. On day 1, the rabbits were divided into four topical treatment groups: (1) 0.5% FCV 4x/day × 10 d; (2) 0.1% FCV 4x/day × 10 d; (3) 0.5% CDV 2x/day × 7 d; (4) vehicle 4x/day × 10 d. Eyes were cultured for virus on days 0, 1, 3, 4, 5, 7, 9, 11, and 14. The resulting viral eye titers were determined using standard plaque assays. The mean in vitro EC50 for FCV against tested HAdV types ranged from 0.50 to 4.68 µM, whereas those treated with CDV ranged from 0.49 to 30.3 µM. In vivo, compared to vehicle, 0.5% FCV, 0.1% FCV, and 0.5% CDV produced lower eye titers, fewer numbers of positive eye cultures, and shorter durations of eye infection. FCV demonstrated anti-adenovirus activity in vitro and in vivo.


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