Topic:Erythrocytes
Erythrocytes, or red blood cells, are the most abundant cell type in the equine circulatory system and are responsible for transporting oxygen from the lungs to tissues throughout the body. They also facilitate the return of carbon dioxide from tissues to the lungs for exhalation. Equine erythrocytes are characterized by their biconcave disc shape, which enhances their flexibility and surface area for gas exchange. The lifespan of erythrocytes in horses is approximately 140-150 days, after which they are removed from circulation and broken down, primarily in the spleen. Variations in erythrocyte count, size, and morphology can indicate various health conditions, including anemia, dehydration, and certain metabolic disorders. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and clinical implications of erythrocytes in equine health.
Development of a stable transgenic Theileria equi parasite expressing an enhanced green fluorescent protein/blasticidin S deaminase. Theileria equi, an intraerythrocytic protozoan parasite, causes equine piroplasmosis, a disease which negatively impacts the global horse industry. Genetic manipulation is one of the research tools under development as a control method for protozoan parasites, but this technique needs to be established for T. equi. Herein, we report on the first development of a stable transgenic T. equi line expressing enhanced green fluorescent protein/blasticidin S deaminase (eGFP/BSD). To express the exogenous fusion gene in T. equi, regulatory regions of the elongation factor-1 alpha (ef-1α) gene were id...
Investigation of erythrocyte antigen frequencies in draft horse populations in Japan to assess blood donor suitability. Erythrocyte alloantigen frequencies of draft horses in Japan were investigated to assess blood donor suitability for transfusion. Here, 148 Japanese draft, 69 Percheron, and 65 Breton horses were blood-typed and subjected to an indirect antiglobulin test. Regarding the major immunogenic factors, the rates of Aa- and Qa-negative horses ranged from 0.35 to 0.49 and from 0.82 to 1.00, respectively. The rate of alloantibody-positive horses ranged from 0.12 to 0.35. Although the prevalence of alloantibodies in these horses was higher than that expected naturally, the rates of Aa- and Qa-negative ho...
Validation of a flow cytometric assay to detect intraerythrocytic reactive oxygen species in horses. Oxidative stress refers to the accumulation of reactive oxygen species (ROS). Most assays for ROS detection are costly, laborious, and usually use indirect markers. The use of 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) is a possible alternative. This substance becomes a fluorochrome when oxidized by ROS, with the resultant fluorescence proportional to ROS concentration. Erythrocytes are highly exposed to ROS, resulting in cell damage and consequently impaired oxygen delivery. The effects of this exposure in physiologic and pathologic conditions necessitate an improvement in ROS detec...
Anti-piroplasmic activity of novobiocin as heat shock protein 90 inhibitor against in vitro cultured Theileria equi and Babesia caballi parasites. Theileria equi and Babesia caballi are the causative agents of equine piroplasmosis (EP). Currently, imidocarb dipropionate (ID) is the only available drug for treating the clinical form of EP. Serious side effects and incomplete clearance of infection is a major drawback of ID. Heat-shock proteins (Hsp) play a vital role in the life cycle of these haemoprotozoans by preventing alteration in protein conformation. These Hsp are activated during transmission of EP sporozoites from the tick vector (poikilotherm) to the natural host (homeotherm) and facilitate parasite survival. In the present stu...
Identification of Hypoxia-inducible factor (HIF) stabilizer roxadustat and its possible metabolites in thoroughbred horses for doping control. Hypoxia-inducible factor (HIF) stabilizer belongs to a novel class of pharmacologically active substances, which are capable of inducing the endogenous erythropoietic system. The transcriptional activator HIF has been shown to significantly increase blood hemoglobin and is well set for the treatment of anemia resulting from chronic kidney disease. This research work reports a comprehensive study of the most popular HIF stabilizer roxadustat and its metabolites in thoroughbred horse urine after oral administration. The plausible structures of the detected metabolites were postulated using liqui...
Effect of First Long-Term Training on Whole Blood Count and Blood Clotting Parameters in Thoroughbreds. Training has a strong effect on the physiology of hematological parameters and blood coagulation, both in humans and in horses. Several blood changes have been reported after exercise in horses but available data differ. We aimed to investigate modifications in complete blood count and some hemostatic parameters induced by the first training period in young untrained Thoroughbred racehorses to detect a possible labile blood coagulability in racehorses. Twenty-nine untrained 2-year-old Thoroughbreds were followed during their incremental 4-month sprint exercise schedule. Blood collection was pe...
Molecular detection of Theileria equi in horses from Veracruz, Mexico. Equine piroplasmosis is a tropical parasitic disease caused by several intraerythrocytic members of the genera Babesia and Theileria. These pathogens are transmitted by multiple tick species and are considered as important exotic microorganisms in several countries. Equine piroplasmosis causes significant economic losses due to abortions, decreased activity and even death of equines, making surveillance of these infectious disease essential. In the northern and eastern parts of Mexico, few molecular and serological reports have been made on the presence and exposure of horse to these agents. F...
Label-free proteomics for discovering biomarker candidates of RAD140 administration to castrated horses. Selective androgen receptor (AR) modulators (SARMs) are potent anabolic agents with a high potential of misuse in horseracing and equestrian sports. In this study, we applied label-free proteomics to discover plasma protein biomarkers in geldings (castrated horses) after administration with a popular SARM named RAD140. Tryptic peptides were prepared from plasma samples and analyzed by nano-flow ultrahigh-performance liquid chromatography-high-resolution tandem mass spectrometry (nano-UHPLC-HRMS/MS) using data-independent acquisition (DIA) method. Orthogonal projection on latent structure-discr...
Optimal double-spin method for maximizing the concentration of platelets in equine platelet-rich plasma. This study optimized the double-spin conditions for preparing equine platelet-rich plasma (PRP): leukocyte-rich PRP (L-PRP) and leukocyte-poor PRP (P-PRP). Whole blood samples were centrifuged at various double-spin conditions. Both L-PRP and P-PRP were prepared at each stage, and complete blood counts and growth factor concentrations were compared. Samples centrifuged at 160 × 900 g, 160 × 2,000 g, and 400 × 2,000 g exhibited the highest platelet counts. P-PRP had significantly lower leukocyte and erythrocyte contents than L-PRP, especially at 400 × 2,000 g. No significant differences wer...
Endochin-like quinolone-300 and ELQ-316 inhibit Babesia bovis, B. bigemina, B. caballi and Theileria equi. The most common apicomplexan parasites causing bovine babesiosis are Babesia bovis and B. bigemina, while B. caballi and Theileria equi are responsible for equine piroplasmosis. Treatment and control of these diseases are usually achieved using potentially toxic chemotherapeutics, such as imidocarb diproprionate, but drug-resistant parasites are emerging, and alternative effective and safer drugs are needed. The endochin-like quinolones (ELQ)-300 and ELQ-316 have been proven to be safe and efficacious against related apicomplexans, such as Plasmodium spp., with ELQ-316 also being effective aga...
Validation of a Rapid Bronchoalveolar Lavage Fluid Colorimetric Evaluation for Assessing the Severity of Exercise-Induced Pulmonary Hemorrhage in Horses in Field Conditions. Diagnosis and assessment of severity of exercise-induced pulmonary hemorrhage (EIPH) relies on postexercise visualization of fresh blood in the airways via tracheobronchoscopic examination (TBE) and/or counting erythrocytes in bronchoalveolar lavage fluid (BALFRBC). Determining the BALFRBC is more sensitive than TBE but its usefulness is hampered by the need to have BALFRBC counted at a laboratory. We explored the feasibility of evaluating the severity of EIPH by using a color chart comprised of five shades of red and matching those colors with the color of BALF immediately following collectio...
Infection dynamics of Theileria equi in carrier horses is associated with management and tick exposure. The tick-borne equine hemoparasite, Theileria equi, is endemic in many parts of the world where prevalence may be high, and most infected horses are apparently healthy but serve as life-long carriers. To determine the factors that affect T. equi dynamics, we followed parasitic loads in apparently healthy horses at four time points during one year. A total of 1094 blood samples were collected from 395 horses, along with ticks and demographic and clinical data. Infection and load of T. equi were tested by PCR and qPCR, and for the spring dataset, infection was also tested serologically by IFAT (...
Alterations of cardiac and renal biomarkers in horses naturally infected with theileria equi. Equine theileriosis due to Theileria equi is probably the most widespread and pathogenic disease of equines, which comes with major cardiac and renal complications. This study was undertaken to investigate the biomarkers of cardiac and renal functions in horses infected with T. equi and determine the association between these parameters and the level of parasitemia. Giemsa-stained blood smears from 300 horses with ages of 3-4 years old were examined for detection of T. equi on erythrocytes. Moreover, multiplex PCR was employed for confirmation of the diagnosis in the 28 positive cases. Based o...
Evidence that human and equine erythrocytes could have significant roles in the transport and delivery of amino acids to organs and tissues. Erythrocytes have a well-defined role in the gaseous exchange of oxygen and carbon dioxide in the mammalian body. The erythrocytes can contain more than half of the free amino acids present in whole blood. Based on measures showing that venous erythrocyte levels of amino acids are much less than arterial erythrocyte levels, it has previously been proposed that erythrocytes also play a role in the delivery of amino acids to tissues in the body. This role has been dismissed because it has been assumed that to act as an amino acid transport vehicle, the erythrocytes should release their entire a...
Preparation of Monoclonal Antibody Against EMA-1 and Development of Rapid Serological Detection Method for Theileria equi Infection, Xinjiang, China. The erythrocytic-stage surface protein equi merozoite antigen 1 (EMA-1) of Theileria equi is a major candidate for the development of a diagnostic antigen for equine piroplasmosis. In this study, BALB/c mice were immunized with purified recombinant EMA-1 to prepare monoclonal antibody (mAb) against T. equi EMA-1, and 1 mAb 5H2 was obtained that showed good reaction with infected red blood cells (RBC) in the indirect immunofluorescence assay (IFA). To develop a rapid serological detection method for T. equi infection in Xinjiang Uygur Autonomous Region, China, recombinant EMA-1 originating from...
Hematology Red Flags: The Value of Blood Smear Examination in Horses. This article uses a case-based approach, complemented with diagnostic algorithms and images, to highlight hematologic changes of pathologic relevance in horses, namely, marked erythrocytosis, anemia or leukocytosis, inflammatory leukograms, lymphocytosis in adult horses, thrombocytopenia, and pancytopenia. These hematologic abnormalities occur with certain diseases and their identification can help clinicians narrow to down differential diagnostic lists. This article highlights the importance of blood smear examination, particularly, but not only, when numerical red flags are identified on aut...
Relationship between tracheobronchoscopic score and bronchoalveolar lavage red blood cell numbers in the diagnosis of exercise-induced pulmonary hemorrhage in horses. Exercise-induced pulmonary hemorrhage (EIPH) is diagnosed and its severity assessed by post-exercise tracheobronchoscopy, and enumeration of bronchoalveolar lavage fluid red blood cells (BALFRBC). Minimal information is available regarding the relationship of tracheobronchoscopy score to BALFRBC number. Objective: Evaluate the relationship between BALFRBC number and tracheobronchoscopy scores and determine their diagnostic sensitivities. Methods: Nine sedentary horses, 21 fit Thoroughbreds, 129 Barrel Racers. Methods: Normal BALFRBC number and the effect of bronchoalveolar lavage (BAL) on it w...
Babesia (Theileria) equi genotype A among Indian equine population. Equine piroplasmosis, caused by Babesia (Theileria) equi, is well reported from many parts of India. However, literature regarding its prevalence from semi arid India is limited. Alongside, there is complete absence of information about genetic characterization of B.(T.) equi and the associated genotypes from India. In the present study, the prevalence of B.(T.) equi was studied from semi arid India using 18S ribosomal gene based PCR assay. An overall prevalence rate of 10.46% was recorded. PCR was more sensitive and specific in comparison with blood smears. The found isolates were sequenced. ...
Differential Expression of Monocarboxylate Transporter 1 and Ancillary Protein CD147 in Red Blood Cells of Show Jumping Horses. We compare the expression levels of the lactate transporter complex consisting of the lactate transporter, monocarboxylate transporter 1 (MCT1), and its ancillary protein, cluster of differentiation 147 (CD147), in the membranes of red blood cells (RBCs) from two breeds of jumping horses and associate the expression levels of these proteins with their jumping ability. The expression levels of MCT1 and CD147 proteins on the membranes of RBCs collected from 30 show jumping horses of two different breeds were quantified: the Brazilian Sport Horses (n = 17) and the European Warmbloods (n = 13). ...
Plasmapheresis Effect on Hematological and Biochemical Parameters in Athletic Horses Subjected to Exercise. To evaluate the effect of plasmapheresis on clinical, hematological, and biochemical parameters after exercise, a plasmapheresis session was realized on six jumping horses (plasmapheresis group) that underwent three consecutive days of physical graded exercise. The control group (n = 6) went through the same exercise but not subjected to the plasmapheresis session. Seventeen milliliters of plasma/kg of body weight was harvested from each horse. The procedure was well tolerated by the horses. The plasmapheresis leads to a significant increase of the hemoglobin, hematocrit, red blood cell, whit...
Lochial and endometrial cytological changes during the first 10 days post-partum with special reference to the nature of foaling and puerperium in equine. During the puerperium, pregnancy-associated changes of the uterus need to be reversed. The duration of this process is of importance in terms of breeding efficiency and thus monitoring and treatment of the disturbed puerperium are essential. Aim of this investigation was to identify changes over time in the cellular composition of samples from endometrium and lochia in 120 mares with different obstetrical and puerperal history. In regular examinations up to 10 days post-partum the uterine involution was assessed by transrectal palpation and ultrasound. The vagina and cervix were examined using...
Aging Markers in Equine Red Blood Cells. Detection of hematopoietic activity in horses is a challenge due to the lack of cells carrying reticulocyte markers such as RNA remnants or CD71 in the circulation. In this study, we fractionated equine red cells according to their density and analyzed the cells forming low (L), medium (M), and high (H) density fractions for markers of aging such as membrane loss, oxidation, and alterations in the intracellular free Ca levels. Cells forming L and M fraction were highly heterogeneous in projected areas and shapes, and had higher propensity to swell in response to hypo-osmotic challenge than the...
Near-Newtonian Blood Behavior – Is It Good to Be a Camel? From a certain level of exercise-intensity onward, hematocrit increases in horses, which brings more oxygen carriers into the bloodstream. Camels, however, when used in competitive racing could be even in need of iron supplementation and blood transfusions due to a severe reduction of their available hematocrit compared to their resting hematocrit. Since the extrinsic and intrinsic mechanical properties of camel erythrocytes (RBC) are so different compared to RBCs of other mammals, the question arises whether this observation might be a response to endurance exercise aiming at keeping the RBC ...
Evaluation of automated erythrocyte methodology in new world camelids using the ADVIA 2120 hematology analyzer. Accurate erythrocyte measurements with ADVIA hematology analyzers require isovolumetric cell sphering in one reaction and hemolysis in another. However, camelid erythrocytes are resistant to sphering and osmotic lysis, and no published evaluation of ADVIA methods for camelids exists. Objective: The objectives were to demonstrate whether camelid erythrocytes sphere in the ADVIA red blood cell/platelet (RBC/PLT) reagent and lyse in the ADVIA cyanide HGB reagent, and to determine optimal ADVIA settings for camelids. Methods: Camelid and canine blood were diluted to 1:625 in RBC/PLT reagent and ev...
The Effects of Xylazine Administration on Peripheral Leukocyte Values in Thoroughbred Horses. This study was conducted to determine whether xylazine administration is associated with clinically significant changes on leukocyte numbers in horses, as has been previously reported in other species. The study was designed to detect 20% changes in primary endpoint leukocyte parameters with 85% statistical power. No clinically significant changes in leukocyte numbers meeting the requirements of the statistical analysis were detected; no consistent changes capable of confounding a clinical diagnosis or treatment were detected. No gross changes in secondary endpoints including erythrocyte and p...
Erythrocytosis and fatigue fractures associated with hepatoblastoma in a 3-year-old gelding. Hepatoblastoma was diagnosed in a 3-year-old Thoroughbred gelding presented with forelimb lameness with bilateral fatigue fractures of the proximal third metacarpal bones. An abdominal mass was detected on ultrasound examination of the abdomen. Absolute erythrocytosis was diagnosed after clinical and haematological evaluation. The fractured metacarpal bones were surgically removed but complications after surgery were fatal. The liver mass was diagnosed as a hepatoblastoma based on histology and immunochemical staining. The combination of hepatoblastoma and fatigue fractures has not been descri...
First Report of Acute Bilateral Hyphema in a Theileria equi-Infected Kathiawari Horse. Theileria equi is a tickborne hemoparasite that can cause severe illness in equids. In this report, we are describing a condition of acute bilateral hyphema in a 4-month-old Kathiawari filly infected with T. equi. The horse showed clinical signs such as fever, lethargy, icterus, tachycardia, tachypnea, and bilateral hyphema. Laboratory diagnosis revealed anemia and thrombocytopenia. Atypical clinical manifestation of bilateral hyphema, to our knowledge, has never been reported so far in equids infected with T. equi. The diagnosis was confirmed by microscopic examination of Geimsa-stained blo...
Reference intervals for haematological parameters in the Lusitano horse breed. The Lusitano horse is an autochthonous Portuguese breed with a growing worldwide expansion. Our objective was to establish reference intervals for haematological parameters using the haematological cell counter LaserCyte (IDEXX). For this purpose, blood samples from 100 healthy adult horses (13 females and 87 males, ranging from 3 to 25 years of age) were analysed. The reference intervals were estimated following the ASVCP guidelines with the Reference Value Advisor software. The obtained reference intervals were 6.4-10.1 × 1012/L for red blood cells, 30.6-45.1% for haematocrit, 11.6-17.1 g/d...
Evolution and diversity of the EMA families of the divergent equid parasites, Theileria equi and T. haneyi. The equine parasite Theilera equi continues to curtail global equine commerce due primarily to its ability to persist indefinitely in the immunocompetent horse. Details regarding the parasite life cycle, pathogenesis and mechanism of persistence remain unclear. The recently discovered T. haneyi is also capable of persistence in the horse, creating a potential reservoir for additional infections. These two divergent parasites share a unique gene family that expresses surface merozoite antigens, or equi merozoite antigens (EMAs). The EMA family was maintained in number and size in both parasites...
Biological variation of routine haematology and biochemistry measurands in the horse. Clinical pathology results are typically interpreted by referring to population-based reference intervals. The use of individualised (subject-based) reference intervals is more appropriate for measurands with a high degree of variation between individuals. Objective: To determine the biological variation of routinely analysed equine haematology and biochemistry measurands and calculate indices of individuality and reference change values which enable production of individualised reference intervals, in a group of healthy, privately owned horses. Methods: In a prospective cohort study, thirty-n...