Development of a metabonomic approach based on LC-ESI-HRMS measurements for profiling of metabolic changes induced by recombinant equine growth hormone in horse urine

Despite the worldwide existing regulation banning the use of the recombinant equine growth hormone (reGH) as growth promoter, it is suspected to be used in horseracing to improve performances. Various analytical methods previously developed to screen for its misuse have encountered some limitations in terms of detection timeframes, in particular during the first days following reGH administration. A novel strategy involving the characterization of global metabolomic fingerprints in urine samples of non-treated and reGH-treated horses by liquid chromatography–electrospray–high-resolution mass spectrometry (LC-ESI-HRMS) is described and assessed in this paper in order to develop a new screening tool for growth hormone abuse in horseracing. The strategy involves a limited sample preparation of the urine samples and the use of appropriate software for data processing and analysis. As preliminary work, reproducibility of both sample preparation and mass spectrometry (MS) measurements was evaluated in order to demonstrate the reliability of the method. Application of the developed protocol on two horses demonstrated the suitability of the developed strategy and preliminary results showed significant modifications of the metabolome after treatment with reGH.       

用Dot-ELISA检测马鼻肺炎病毒抗体的研究

用从德国引进的马鼻肺炎(EHV-1)标准毒株经BHK-21细胞传代增殖，免疫家兔，制备高免血清，提取IgG并用辣根过氧化物酶(HRP)进行标记，建立了能够大量、快速、特异地检测马鼻肺炎的斑点-酶联免疫吸附实验(Dot-ELISA)方法，并应用此方法对100份马血、2份野马流产胎儿病料及从野马流产胎儿病料中分离的毒株PH93-1进行了检测，结果证明，本方法具有较好的特异性和敏感性，而且操作简便、快速，是一种适用于马鼻肺炎的诊断、流行病学调查、检疫和监测的良好方法。     

Alphavirus protease inhibitors from natural sources: A homology modeling and molecular docking investigation

Alphaviruses such as Chikungunya virus (CHIKV), O’Nyong–Nyong virus (ONNV), Ross River virus (RRV), Eastern equine encephalitis virus (EEEV), Venezuelan equine encephalitis virus (VEEV), and Western equine encephalitis virus (WEEV), are mosquito-transmitted viruses that can cause fevers, rash, and rheumatic diseases (CHIKV, ONNV, RRV) or potentially fatal encephalitis (EEEV, VEEV, WEEV) in humans. These diseases are considered neglected tropical diseases for which there are no current antiviral therapies or vaccines available. The alphavirus non-structural protein 2 (nsP2) contains a papain-like protease, which is considered to be a promising target for antiviral drug discovery. In this work, molecular docking analyses have been carried out on a library of 2174 plant-derived natural products (290 alkaloids, 664 terpenoids, 1060 polyphenolics, and 160 miscellaneous phytochemicals) with the nsP2 proteases of CHIKV, ONNV, RRV, EEEV, VEEV, WEEV, as well as Aura virus (AURV), Barmah Forest Virus (BFV), Semliki Forest virus (SFV), and Sindbis virus (SINV) in order to identity structural scaffolds for inhibitor design or discovery. Of the 2174 phytochemicals examined, a total of 127 showed promising docking affinities and poses to one or more of the nsP2 proteases, and this knowledge can be used to guide experimental investigation of potential inhibitors.     

In vitro metabolism studies of desoxy‐methyltestosterone (DMT) and its five analogues,and in vivo metabolism of desoxy‐vinyltestosterone (DVT) in horses

The positive findings of norbolethone in 2002 and tetrahydrogestrinone in 2003 in human athlete samples confirmed that designer steroids were indeed being abused in human sports. In 2005, an addition to the family of designer steroids called ‘Madol’ [also known as desoxy‐methyltestosterone ( DMT )] was seized by government officials at the US–Canadian border. Two years later, a positive finding of DMT was reported in a mixed martial arts athlete's sample. It is not uncommon that doping agents used in human sports would likewise be abused in equine sports. Designer steroids would, therefore, pose a similar threat to the horseracing and equestrian communities. This paper describes the in vitro metabolism studies of DMT and five of its structural analogues with different substituents at the 17α position (R ? H, ethyl, vinyl, ethynyl and ²H₃‐methyl). In addition, the in vivo metabolism of desoxy‐vinyltestosterone ( DVT ) in horses will be presented. The in vitro studies revealed that the metabolic pathways of DMT and its analogues occurred predominantly in the A‐ring by way of a combination of enone formation, hydroxylation and reduction. Additional biotransformation involving hydroxylation of the 17α‐alkyl group was also observed for DMT and some of its analogues. The oral administration experiment revealed that DVT was extensively metabolised and the parent drug was not detected in urine. Two in vivo metabolites, derived respectively from (1) hydroxylation of the A‐ring and (2) di‐hydroxylation together with A‐ring double‐bond reduction, could be detected in urine up to a maximum of 46 h after administration. Another in vivo metabolite, derived from hydroxylation of the A‐ring with additional double‐bond reduction and di‐hydroxylation of the 17α‐vinyl group, could be detected in urine up to a maximum of 70 h post‐administration. All in vivo metabolites were excreted mainly as glucuronides and were also detected in the in vitro studies. Copyright © 2015 John Wiley & Sons, Ltd.     

Development and application of a UHPLC‐MS/MS method for the simultaneous determination of 17 steroidal hormones in equine serum

A new, fast and simple analytical method that is able to identify and quantify simultaneously 17 steroid hormones and metabolites (pregnenolone, 17‐OH‐pregnenolone, progesterone, 17‐OH‐progesterone, androsterone, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, testosterone, cortisol, corticosterone, aldosterone, 11‐deoxycortisol, 11‐deoxycorticosterone, dihydrotestosterone, estrone and estradiol) has been developed in equine serum using the ultra‐high‐performance liquid chromatography–tandem mass spectrometry technique. A total of 400 µl of sample was deproteinized with 1000 µl of acetonitrile, evaporated, restored with 50 µl of a solution of 25% methanol and injected in ultra‐high‐performance liquid chromatography–tandem mass spectrometry triple quadrupole. The recovery percentage obtained by spiking the matrix at two different concentrations with a standard mixture of steroid hormones was in all cases higher than 85.60% and with the percentage of coefficient of variation lower than 8.37%. The range of the correlation coefficients of the calibration curves of the analyzed compounds was 0.9922–0.9986, and the limits of detection and limits of quantification were in the range of 0.002–2 and 0.0055–5.5 ng ml⁻¹, respectively. The detected limit of quantification for testosterone (i.e. 50 pg ml⁻¹) is twofold lower with respect to its threshold admitted in geldings plasma (100 pg ml⁻¹ free testosterone). The high sensitivity and the quantitative aspect of the method permitted to detect most of the steroids in equine serum. Once validated, the method was used to quantify 17 steroid hormones in mare, stallion and gelding serum samples. The main steroids detected were corticosterone (range 37.25–51.26 ng ml⁻¹) and cortisol (range 32.57–52.24 ng ml⁻¹), followed by 17‐OH‐pregnenolone, dihydrotestosterone and pregnenolone. Copyright © 2016 John Wiley & Sons, Ltd.     

Quantitation of γ‐aminobutyric acid in equine plasma by hydrophilic interaction liquid chromatography with tandem mass spectrometry

γ‐ Aminobutyric acid is the principal inhibitory neurotransmitter in the central nervous system and regulates the neuronal excitability. There has been anecdotal evidence that γ‐ aminobutyric acid has been used within a few hours prior to competition in equine sports to calm down nervous horses. However, regulating the use of γ‐ aminobutyric acid is challenging because it is an endogenous substance in the horse. γ‐Aminobutyric acid is usually present at low ng/mL levels in equine plasma; therefore, a sensitive method has to be developed to quantify these low background levels. Measuring low concentrations of endogenous γ‐ aminobutyric acid is essential to establish a threshold that can be used to differentiate levels attributable to exogenous administrations of γ‐ aminobutyric acid. A hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry method was developed and validated for the quantitation of γ‐ aminobutyric acid in equine plasma. Calibrators were prepared in artificial surrogate matrix consisting of 35 mg/mL equine serum albumin in phosphate buffered saline. Samples were prepared by protein precipitation with acetonitrile. Utilizing this methodology, a total of 403 equine plasma samples collected post‐competition from horses participating in equestrian events in Canada were analyzed.     

High‐throughput UHPLC–MS/MS method for the detection,quantification and identification of fifty‐five anabolic and androgenic steroids in equine plasma

Anabolic and androgenic steroids (AASs) are synthetic substances related to the primary male sex hormone, testosterone. AASs can be abused in both human and equine sports and, thus, are banned by the International Olympic Committee and the Association of Racing Commissioners International (ARCI). Enforcement of the ban on the use of AASs in racehorses during competition requires a defensible and robust method of analysis. To address this requirement, a high‐throughput ultra high‐performance liquid chromatography–mass spectrometric (UHPLC–MS) method was developed for the detection, quantification and confirmation of 55 AASs in equine plasma. AASs were recovered from equine plasma samples by liquid–liquid extraction with methyl tert‐butyl ether (MTBE). Analytes were chromatographically separated on a sub‐2 µm particle size C₁₈ column with a mobile phase gradient elution and detected by selected‐reaction monitoring (SRM) on a triple quadrupole mass spectrometer. AASs with isobaric precursor ions were either chromatographically resolved or mass spectrometrically differentiated by unique precursor‐to‐product ion transitions. A few of them that could not be resolved by both approaches were differentiated by intensity ratios of three major product ions. All the epimer pairs, testosterone and epitestosterone, boldenone and epiboldenone, nandrolone and epinandrolone, were chromatographically base‐line separated. The limit of detection and that of quantification was 50 pg/ml for most of the AASs, and the limit of confirmation was 100–500 pg/ml. Full product ion spectra of AASs at concentrations as low as 100–500 pg/ml in equine plasma were obtained using the triple quadrupole instrument, to provide complementary evidentiary data for confirmation. The method is sensitive and selective for the detection, quantification and confirmation of multiple AASs in a single analysis and will be useful in the fight against doping of racehorses with AASs. Copyright © 2010 John Wiley & Sons, Ltd.     

液相色谱-串联质谱法快速筛查马饲料中39种违禁药物

建立了同时快速筛查和确证马饲料中39种赛马违禁药物(包含抗心率失常类药物、抗惊厥类药物、止痉挛类药物、抗疟疾类药物、刺激剂、麻醉剂及大麻酚类药物)的液相色谱串联质谱(HPLC-MS/MS)分析方法。样品粉碎后分别经1 mmol/L HClO4溶液和酸化乙腈溶液提取,并通过混合型固相萃取柱净化。采用Agilent Zorbax SB(10.0 cm×2.1 mm i.d.,3.5 μm) 色谱柱,以0.4%甲酸水溶液和0.4%甲酸乙腈为流动相进行梯度洗脱,正离子多反应监测(MRM) 模式下检测。方法对空白饲料3个加标水平下的平均回收率为58%~116%,相对标准偏差为1.6%~20.4%,各类药物线性良好(r2＞0.99)。方法检出限(S/N≥3)和定量下限(S/N≥10)分别为0.2~25.0 μg/kg和1.0~40.0 μg/kg,其中超过67%药物的检出限在2.5 μg/kg以下。实验结果表明,该方法分析时间短,灵敏度、精密度良好,适用于马饲料中上述几类药物的快速筛查和测定。     

Comparison of different liquid chromatography stationary phases in LC-HRMS metabolomics for the detection of recombinant growth hormone doping control

Growth hormone (GH) is a polypeptide suspected of being used in horse racing to speed up physical performances. Despite scientific advances in the recent years, the control of its administration remains difficult. In order to improve it, a metabolomics study through LC-high resolution mass spectrometry measurements was recently initiated to assess the metabolic perturbations caused by recombinant equine growth hormone administration. Few tens of ions not identified structurally were highlighted as compounds responsible for the modification of metabolic profiling observed in treated animals. This previous work was based on the use of Uptisphere Strategy NEC as the chromatographic column. In parallel, more and more metabolomics studies showed the interest of the use of new chromatographic supports such as hydrophilic interaction chromatography for the analysis of polar compounds. It is in this context that an investigation was conducted on Uptisphere HDO and Luna hydrophilic interaction chromatography stationary phases to generate and process urinary metabolomics fingerprints, which could allow to establish a comparison with Uptisphere Strategy NEC. The chromatographic column the most adapted for the detection of new biomarkers of GH administration has been used to set up a relevant statistical model based on the analysis of more than hundred biological samples.