Confirmatory Analysis of Continuous Erythropoietin Receptor Activator and Erythropoietin Analogues in Equine Plasma by LC−MS for Doping Control

Blood Transfusion in Equids—A Practical Approach and Review

Simple Summary

Transfusion medicine is an accessible, technically simple, and often lifesaving tool that can be used in both field and hospital settings, in cases of significant bleeding or anemia. A thorough understanding of the indications, methodology and complications of blood transfusion allows the practitioner to identify cases where administration of whole blood is necessary, and how to safely perform the transfusion. This review collects the current literature surrounding blood transfusion into one readily accessible document to allow clinicians a comprehensive understanding of all aspects of equine blood transfusion, while serving as a reference for performing these procedures.

Abstract

Transfusion medicine is a crucial part of equine intensive and critical care. Blood transfusions can save lives in both acute and chronic cases of anemia, hemorrhage, and hemolysis. It is vital to have a comprehensive theoretical and practical understanding of the techniques, implications, risks, and complications. This review covers the physiology and pathophysiology of conditions requiring transfusion, as well as step by step guidance for practitioners of all experience levels. This review is designed to serve as a practical reference for those who are treating horses in either the field or hospital setting. It aims to provide both theoretical background and easy to locate formulae with guidance that is easy to refer to in a critical situation. When risks and benefits are well understood, these techniques can be confidently employed in critical situations to improve outcomes and save lives.

Defining the specificity of recombinant human erythropoietin confirmation in equine samples by liquid chromatography-tandem mass spectrometry

The proteotypic human EPO peptides YLLEAK (T4), SLTTLLR (T11), TITADTFR (T14), and VYSNFLR (T17) are often used to confirm the presence of recombinant human EPO (rhEPO) in equine samples. Each of these peptides contains one or more isomeric leucine or isoleucine amino acids, raising the possibility that a simple leucine/isoleucine substitution could lead to a false identification when compared with a rhEPO reference standard. To examine this possibility variants of these four peptides were analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). These studies indicate that confirmation of rhEPO in equine samples by immuno-affinity capture and LC-MS/MS analysis is true and accurate. It was also found that chromatography played a greater role in determining LC-MS/MS specificity than tandem mass spectrometry and that, in the case of more hydrophilic peptides, the accuracy of peptide identification could be enhanced by the inclusion of ¹³ C and ¹⁵ N labelled peptide internal standards.

Doping detection in animals: A review of analytical methodologies published from 1990 to 2019

Despite the impressive innate physical abilities of horses, camels, greyhounds, or pigeons, doping agents might be administered to these animals to improve their performance. To control these illegal practices, anti-doping analytical methodologies have been developed. This review compiles the analytical methods that have been published for the detection of prohibited substances administered to animals involved in sports over 30 years. Relevant papers meeting the search criteria that discussed analytical methods aiming to detect and/or quantify doping substances in animal biological matrices published from 1990 to 2019 were considered. A total of 317 studies were included, of which 298 were related to horses, demonstrating significant advances toward the development of doping detection methods for equine sports. However, analytical methods for the detection of doping agents in sports involving other species are lacking. Due to enhanced accuracy and specificity, chromatographic analysis coupled to mass spectrometry detection is preferred over immunoassays. Regarding biological matrices, blood and urine remain the first choice, although alternative biological matrices, such as hair and feces, have been considered. With the increasing number and type of drugs used as doping agents, the analytes addressed in the published papers are diverse. It is very important to continue to detect and quantify these drugs, recognizing those that are most frequently used, in order to punish the abusers, protect animals' health, and ensure a healthier and genuine competition.

Screening and confirmatory analysis of recombinant human erythropoietin for racing camels' doping control

Recombinant human erythropoietin (rHuEPO) belongs to the therapeutic class of erythropoiesis stimulating agents (ESAs) due to its implication in the creation pathway of red blood cells and thus enhancement of oxygenation. Because of this bioactivity, rHuEPO has been considered as a major doping agent in sports competitions for decades. Over the years, doping control laboratories designed several analytical strategies applied to human and animal samples to highlight any misuse. Even though multiple analytical approaches have been reported, none has yet been dedicated to racing camels. Here, we describe an analytical strategy to test camel plasma samples at screening using an ELISA assay and a targeted nano-liquid chromatography-high-resolution tandem mass spectrometry for confirmatory analysis. The method was validated and has been successfully applied to post-race samples, allowing the detection of a positive case of rHuEPO administration.

Erythropoietin as a performance-enhancing drug: Its mechanistic basis, detection, and potential adverse effects

Erythropoietin (EPO) is the main hormone regulating red blood cell (RBC) production. The large-scale production of a recombinant human erythropoietin (rHuEPO) by biotechnological methods has made possible its widespread therapeutic use as well as its misuse in sports. Since the marketing of the first epoetin in 1989, the development has progressed to the third-generation analogs. However, the production of rHuEPO is costly, and the frequent administration of an injectable formula is not optimal for compliance of therapeutic patients. Hence, pharmaceutical industries are currently developing alternative approaches to stimulate erythropoiesis, which might offer new candidates for doping purposes. The hypoxia inducible factors (HIF) pathway is of particular interest. The introduction of new erythropoiesis-stimulating agents (ESAs) for clinical use requires subsequent development of anti-doping methods for detecting the abuse of these substances. The detection of ESAs is based on two different approaches, namely, the direct detection of exogenous substances and the indirect detection, for which the effects of the substances on specific biomarkers are monitored. Omics technologies, such as ironomics or transcriptomics, are useful for the development of new promising biomarkers for the detection of ESAs. Finally, the illicit use of ESAs associates with multiple health risks that can be irreversible, and an essential facet of anti-doping work is to educate athletes of these risks. The aim of this review is to provide an overview of the evolution of ESAs, the research and implementation of the available detection methods, and the side effects associated with the misuse of ESAs.

Detection and confirmation of α-cobratoxin in equine plasma by solid-phase extraction and liquid chromatography coupled to mass spectrometry

α-Cobratoxin (CTX) is a large peptide (71 amino acids) with strong analgesic effect and may be misused in sports such as horse racing. To prevent such misuse, a sensitive method is required for detection and confirmation of the toxin in equine samples. CTX was extracted from equine plasma using an optimized mixed-mode solid-phase extraction (SPE) procedure. Extracted CTX was reduced with dithiothreitol and alkylated with iodoacetamide, and then was digested by trypsin at 56°C for 30min. The digest was analysed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), and tryptic peptides T2 (³CFITPDITSK¹²) and T4 (²⁴TWCDAFCSIR³³) were monitored for detection and confirmation of CTX. The limit of detection (LOD) was 0.05ng/mL for CTX in plasma, and the limit of confirmation (LOC) 0.2ng/mL. Unlike small peptides consisting of the 20 canonical amino acids, CTX was stable in equine plasma at ambient temperature for at least 24h. The developed analytical method was successfully applied to analysis of incurred plasma samples; CTX was detected in plasma collected 15min through 36h post subcutaneous administration of CTX (2.0mg dose) to a research horse, and confirmed 30min through 24h. Additionally, an approach named "reliable targeted SEQUEST search" has been proposed for assessing the specificity of T2 at product ion spectrum level for confirmation of CTX. T2 is uniquely specific for CTX, as evaluated with this approach and BLAST search. Furthermore, the effect of dimethyl sulfoxide (DMSO) as a mobile phase additive on electrospray (ESI) response of T2 and T4, background noise level and signal to noise ratio (S/N) was examined; DMSO increased signal intensity of T2 and T4 by a factor of less than 2. It is the first report that DMSO raised background noise level and did not improve S/N for the peptides, to the authors' knowledge. The developed analytical method may be applicable for analysis of CTX in plasma from other species such as greyhound dogs or even human beings.

Recent developments in doping testing for erythropoietin

The constant development of new erythropoiesis-stimulating agents (ESAs), since the first introduction of recombinant erythropoietin (rhEpo) for clinical use, has also necessitated constant development of methods for detecting the abuse of these substances. Doping with ESAs is prohibited according to the World Anti-Doping Code and its prohibited list of substances and methods. Since the first publication of a direct and urine-based detection method in 2000, which uses changes in the Epo isoform profile as detected by isoelectric focusing in polyacrylamide slab gels (IEF-PAGE), the method has been constantly adapted to the appearance of new ESAs (e.g., Dynepo, Mircera). Blood had to be introduced as an additional matrix, because Mircera (a PEGylated Epo) is best confirmed in serum or plasma after immunoaffinity purification. A Mircera ELISA was developed for fast screening of sera. With the appearance of Dynepo and copy epoetins, the additional application of sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE or equivalent) became necessary. The haematological module of the Athlete Biological Passport is the latest development in multivariable indirect testing for ESA doping. The article summarizes the main strategies currently used in Epo anti-doping testing with special focus on new developments made between 2009 and 2010.