Development and validation of a liquid chromatography coupled to mass spectrometer (LC-MS) method for the simultaneous quantification of estrone-3-sulfate, progesterone, estrone and estradiol in serum of mares and American bisons

Plasma relaxin, estrogens and progestogens concentration in coldblooded and hot-blood mares in the second half of gestation

Monitoring estrogens, progestogens, and relaxin plasma concentration can be important for determining pregnancies at risk of failure in mares. However, significant breed-related differences in values of reproductive hormones are known, and data concerning coldblooded (CB) mares are missing. The aim of the study was to determine and compare serum relaxin, estrone sulphate (E1S), estradiol-17β (E2), and progestogens concentration in pregnant CB and hot-blood (HB) mares during the second half of gestation. Blood samples obtained from 94 healthy mares in the second half of gestation with known mating dates were analyzed. Samples were collected from 36 CB mares aged from 3 to 16 years and 58 HB mares aged from 4 to 17 years. The hormone concentrations were measured using immunoenzymatic equine species-specific commercial kits. The serum relaxin concentration was almost three times lower in CB, whereas E1S and E2 almost twice as low, as compared to HB mares (P < 0.05). In conclusion, the extremely low concentration of relaxin in CB mares could be one reason for the increased amounts of difficult parturition requiring veterinary intervention noted in these breeds.

Sample Preparation Techniques for Growth-Promoting Agents in Various Mammalian Specimen Preceding MS-Analytics

The misuse of growth-promoting drugs such as beta-2 agonists and steroids is a known problem in farming and sports competitions. Prior to the analysis of biological samples via liquid chromatography (LC)-mass spectrometry (MS) or gas chromatography (GC)-MS, sufficient sample preparation is required to reliably identify or determine the residues of drugs. In practice, broad screening methods are often used to save time and analyze as many compounds as possible. This review was conceptualized to analyze the literature from 2018 until October 2023 for sample preparation procedures applied to animal specimens before LC- or GC-MS analysis. The animals were either used in farming or sports. In the present review, solid phase extraction (SPE) was observed as the dominant sample clean-up technique for beta-2 agonists and steroids, followed by protein precipitation. For the extraction of beta-2 agonists, mixed-mode cation exchanger-based SPE phases were preferably applied, while for the steroids, various types of SPE materials were reported. Furthermore, dispersive SPE-based QuEChERs were utilized. Combinatory use of SPE and liquid-liquid extraction (LLE) was observed to cover further drug classes in addition to beta-2 agonists in broader screening methods.

Analysis of progesterone and estrone-sulfate in feces of American Bison using liquid chromatography coupled to mass spectrometry: Technical validation and correlation with blood levels

American Bison's wild nature limits blood sample availability to study its endocrinology. This report describes progesterone (P4) and estrone-sulfate (E1S) assays in American Bison feces using Liquid Chromatography coupled with Mass Spectrometry (LC-MS). In 2 ranches, samples of feces (n = 73) and serum (n = 93) were collected in pregnant and nonpregnant American Bison. Feces samples (250 mg) were extracted with methanol, purified, and concentrated. Then, feces and serum samples were assayed using LC-MS, according to our previously described technique. Fecal matrix homogeneity was determined by measuring steroids in different areas of the sample and concentration evolutions were evaluated after storage at room temperature. During the validation process, lower limits of quantification were 20 pg/g (E1S) and 4 ng/g (P4) by meeting the following criteria: relative standard deviation <15% and relative bias <15%. By measuring hormones in different spots from the same sample, a moderate variability for E1S (coefficient of variation [CV] up to 21.3%) and a high variability for P4 (CV up to 85.5%) were highlighted. Correlation between concentrations in feces and in serum was higher for E1S (r = 0.77) than for P4 (r = 0.65) and P4 could be assayed in pregnant and nonpregnant animals whereas E1S was only present in pregnant. Feces storage at room temperature induced modification of steroid concentrations. The quantification of E1S and, at a lower level, of P4 in feces is an interesting alternative to serum assay to describe the pregnancy-related evolution of these steroids in American Bisons, with feces ideally stored frozen and mixed before the LC-MS procedures.

Evolution of 17-β-estradiol, estrone and estrone-sulfate concentrations in late pregnancy of different breeds of mares using Liquid Chromatography and Mass Spectrometry

This study describes 17-β-estradiol (E2), estrone (E1) and estrone-sulfate (E1S) concentrations between 4 and 11 months in healthy equine pregnancies of two different breeds using Liquid Chromatography coupled to Mass-Spectrometry (LC-MS). In 2 stud-farms including 15 Spanish PureBred (SPB) and 11 Showjumping (SJ) types mares, combined thickness of the uterus and the placenta (CTUP) was measured and blood was sampled monthly between 4 and 11 months of gestation. Concentrations of E2, E1 and E1S were assayed with LC-MS in mares with normal CTUP. Effects of breed, day of pregnancy and mare's parity and age on estrogens concentrations were investigated. Peak of E2 was observed at 5 months (median: 46.4 pg/mL; maximum: 201.5 pg/mL). A strong correlation was observed between E1 and E1S (p < 0.0001, r = 0.85). Peak of E1 (median: 571.0 pg/mL; maximum: 1641.9 pg/mL) and E1S (median: 573.6 ng/mL; maximum: 997.6 ng/mL) concentrations was observed at the 5th month and then E1S decreased quicker than E1 until the end of pregnancy. Higher E2 and E1 concentrations were observed in SJ than in SPB mares between the 6th and the 8th months. No difference between breeds was observed for E1S monthly evolution. Estrogen peak values were all observed at 5 months. Unlike recent LC-MS studies, E1S values observed here were in the same range than those previously established using immuno-assays. After the 6th month, E1S decreased quicker than E1. Effect of breed only observed on non-sulfonated estrogens should be further confirmed. These findings confirm that sulfonation activity of the allantochorion may be limited after the 6th month.

Study on the Preparation of Estrone Molecularly Imprinted Polymers and Their Application in a Quartz Crystal Microbalance Sensor via a Computer-Assisted Design

Computer simulations are widely used for the selection of conditions for the synthesis of molecularly imprinted polymers and can rapidly reduce the experimental cycle time and save labor and materials. In this paper, estrone molecularly imprinted polymers (E1-MIPs) are designed at the M062X/6-311+G(d,p) level with itaconic acid (IA) as the functional monomer. The imprinted molar ratio between E1 and IA was optimized, cross-linkers and solvents were screened, and the nature of interactions between E1 and IA was explored. The simulated results showed that pentaerythritol triacrylate was the best cross-linker. Meanwhile, when the imprinted molar ratio between E1 and IA was 1:4, the E1–IA complex had the largest amount of hydrogen bonds, the lowest binding energy, and the strongest stability. Using the simulation results as guidance, the E1-MIPs were prepared to modify the electrons of a quartz crystal microbalance (QCM) sensor. The experimental studies showed that the E1-MIPs-QCM sensor had the highest adsorption capacity to E1 in comparison with their analogues, and the lowest detection value of the sensor was 16.00 μg/L. The computer simulations and experimental studies could provide guidance for synthesize novel E1-MIPs materials. It also could provide important references and directions for the application of E1-MIPs.

Toxicokinetics of β-Amanitin in Mice and In Vitro Drug-Drug Interaction Potential

The toxicokinetics of β-amanitin, a toxic bicyclic octapeptide present abundantly in Amanitaceae mushrooms, was evaluated in mice after intravenous (iv) and oral administration. The area under plasma concentration curves (AUC) following iv injection increased in proportion to doses of 0.2, 0.4, and 0.8 mg/kg. β-amanitin disappeared rapidly from plasma with a half-life of 18.3−33.6 min, and 52.3% of the iv dose was recovered as a parent form. After oral administration, the AUC again increased in proportion with doses of 2, 5, and 10 mg/kg. Absolute bioavailability was 7.3−9.4%, which resulted in 72.4% of fecal recovery from orally administered β-amanitin. Tissue-to-plasma AUC ratios of orally administered β-amanitin were the highest in the intestine and stomach. It also readily distributed to kidney > spleen > lung > liver ≈ heart. Distribution to intestines, kidneys, and the liver is in agreement with previously reported target organs after acute amatoxin poisoning. In addition, β-amanitin weakly or negligibly inhibited major cytochrome P450 and 5′-diphospho-glucuronosyltransferase activities in human liver microsomes and suppressed drug transport functions in mammalian cells that overexpress transporters, suggesting the remote drug interaction potentials caused by β-amanitin exposure.

Response mechanism of gut microbiome and metabolism of European seabass (Dicentrarchus labrax) to temperature stress

In animals, the gut microbiome is vital to growth, and changes in the composition of these microbial communities may affect growth and adaptability to the environment. Temperature is another important factor that influences the healthy growth of animals. To date, the mechanism by which juvenile European seabass (Dicentrarchus labrax) and their symbiotic flora adapt to changes in environmental temperature is not well understood. Therefore, we evaluated the effect of temperature on the gut microbiota and metabolism of European seabass juveniles. We used 16S rRNA gene amplicon sequencing and non-targeted liquid chromatography with tandem mass spectrometry (LC-MS/MS)-based metabolomics to study the gut microbes of European seabass after 60 days of rearing of water temperature at 10 °C (T1), 15 °C (T2) and 20 °C (T3). At the phylum level, the abundance of the gut microbiota did not differ significantly among the three groups after 60 days of cultivation. At the genus level, however, the abundance of Faecalibacterium, Filifactor, Butyricicoccus, and Erysipelotrichaceae UCG-006 in the intestines differed significantly among the temperature groups. Compared with T2, the relative abundance of Filifactor in T1 was significantly increased, while Faecalibacterium was significantly decreased, while the relative abundance of Butyricicoccus and Erysipelotrichaceae UCG-006 in T3 was significantly increased. The LC-MS/MS analysis revealed 107 metabolites in the 10 °C group and 68 metabolites in the 20 °C group that differed significantly from those in the intestines of fish in the 15 °C control group. These metabolites are closely related to several metabolic pathways, including amino acid metabolism, glucose and lipid metabolism, and the tricarboxylic acid cycle. Correlation analysis of the Intestine microbiota, metabolic pathways, and metabolites identified metabolic pathways and metabolites that were strongly related to the observed significant differences in the microbiome among the temperature groups. These results show that temperature can induce significant changes in the gut microbiota and metabolism of European seabass juveniles, and that significant changes in metabolites may be mediated through the interaction of the microbiome and metabolic pathways.

American Bison (Bison bison) reproductive endocrinology: serum Pregnancy Associated Glycoproteins (PAG), Progesterone, Estrone and Estrone-Sulfate in non pregnant animals and during gestation

This study describes concentrations of Pregnancy Associated Glycoproteins (PAG), progesterone (P4), estrone (E1) and estrone-sulfate (E1S) in American Bison sera. In 2 ranches, mature American Bison were sampled once a year for 2 yr. Subsequent American Bison cows calving days were reported. PAG concentration was determined by Radio-Immuno Assay, whereas P4, E1 and E1S were assayed using Liquid Chromatography and Mass Spectrometry. Concentrations were compared between American Bison bulls (B, n = 7), Nonpregnant cows (NP, n = 32), first (1TP, n = 3), second (2TP, n = 26) and third (3TP, n = 15) trimester of pregnancy. Seven American Bison bulls and 92 cows were sampled, 51 calved during these 2 yr. Calving occurred mostly in spring (74.5%), but also in summer (13.7%) and fall (11.8%). PAG and P4 were higher in 2TP and 3TP than B and NP (P< 0.0001). P4 was non-basal in B and NP. E1 and E1S were correlated (P< 0.0001; r = 0.76) and increased in 2TP and 3TP when compared with B and NP (P< 0.01). Moreover, E1S was higher in 3TP than in 2TP (P< 0.0001) and correlated to pregnancy day (P< 0.0001; r = 0.60). Breeding American Bison in Belgium induces a calving seasonality loss. P4 slowly increases in 1TP and remains steady and high in 2 and 3TP. P4 non-basal and variable concentrations in B or NP disable its use as gestation marker. American Bison produce PAG in the 2 and 3TP, but Estrone-sulfate assay seems to be the best pregnancy marker during the 2 last trimesters as it could help to estimate the gestation period.

Assessment of Age Effects on Ovarian Hemodynamics Using Doppler Ultrasound and Progesterone Concentrations in Cycling Spanish Purebred Mares

Simple Summary

Power Doppler is a non-invasive imaging technique that allows complete monitoring of the ovary changes in cycling mares. We use Power Doppler to investigate differences in follicular diameter and corpus luteum area as well as in follicular and corpus luteum blood flows between young and mature Spanish Purebred mares. Young mares had higher follicular and corpus luteum blood flows as well as higher blood progesterone levels. Moreover, we found that blood progesterone levels could be predicted in both groups from corpus luteum blood flow with moderate precision and accuracy. These results support the usefulness of Power Doppler to monitor ovarian hemodynamics and the suitability of corpus luteum blood flow to estimate blood progesterone levels in cycling mares.

Abstract

In equine reproduction, accurate and timely detection of the moment of ovulation is of great importance. Power Doppler ultrasound technology is a non-invasive method that enables to assess the morpho-echogenic features and blood flow changes during the estral cycle in mares. The objective of the present study was to evaluate the influence of age on ultrasonographic parameters (follicular diameter, follicular blood flow—FBF, corpus luteum (CL) area and corpus luteum blood flow—CLBF) and blood plasma progesterone concentrations in cycling Spanish Purebred mares (15 less than 8 years old and 15 equal o higher than 8 years old). The ultrasound images obtained were analyzed with the Image Colour Summarizer software, which allows the quantification of the pixels of each image. Young mares had significantly higher FBF, CLBF and plasma progesterone levels. Moreover, linear regression analysis showed that blood progesterone levels could be predicted in both groups from CLBF with moderate precision and accuracy. In conclusion, Power Doppler was useful to assess ovarian hemodynamics. Our results support that age is a factor that significantly influences FBF and CLBF as well as blood progesterone concentration in mares. More studies would be needed to develop high precision and accuracy predictive models of blood progesterone concentration from CLBF measured by Power Doppler.