BEVA primary care clinical guidelines: Diagnosis and management of equine pituitary pars intermedia dysfunction.

BACKGROUND: Pituitary pars intermedia dysfunction (PPID) is a prevalent, age-related chronic disorder in equids. Diagnosis of PPID can be challenging because of its broad spectrum of clinical presentations and disparate published diagnostic criteria, and there are limited available treatment options. OBJECTIVES: To develop evidence-based primary care guidelines for the diagnosis and treatment of equine PPID based on the available literature. STUDY DESIGN: Evidence-based clinical guideline using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework. METHODS: Research questions were proposed by a panel of veterinarians and developed into PICO or another structured format. VetSRev and Veterinary Evidence were searched for evidence summaries, and systematic searches of the NCBI PubMed and CAB Direct databases were conducted using keyword searches in July 2022 and updated in January 2023. The evidence was evaluated using the GRADE framework. RESULTS AND RECOMMENDATIONS: The research questions were categorised into four areas: (A) Case selection for diagnostic testing, pre-test probability and diagnostic test accuracy, (B) interpretation of test results, (C) pharmacological treatments and other treatment/management options and (D) monitoring treated cases. Relevant veterinary publications were identified and assessed using the GRADE criteria. The results were developed into recommendations: (A) Case selection for diagnostic testing and diagnostic test accuracy: (i) The prevalence of PPID in equids aged ≥15 years is between 21% and 27%; (ii) hypertrichosis or delayed/incomplete hair coat shedding provides a high index of clinical suspicion for PPID; (iii) the combination of clinical signs and age informs the index of clinical suspicion prior to diagnostic testing; (iv) estimated pre-test probability of PPID should be considered in interpretation of diagnostic test results; (v) pre-test probability of PPID is low in equids aged <10 years; (vi) both pre-test probability of disease and season of testing have strong influence on the ability to diagnose PPID using basal adrenocorticotropic hormone (ACTH) or ACTH after thyrotropin-releasing hormone (TRH) stimulation. The overall diagnostic accuracy of basal ACTH concentrations for diagnosing PPID ranged between 88% and 92% in the autumn and 70% and 86% in the non-autumn, depending on the pre-test probability. Based on a single study, the overall diagnostic accuracy of ACTH concentrations in response to TRH after 30 minutes for diagnosing PPID ranged between 92% and 98% in the autumn and 90% and 94% in the non-autumn, depending on the pre-test probability. Thus, it should be remembered that the risk of a false positive result increases in situations where there is a low pre-test probability, which could mean that treatment is initiated for PPID without checking for a more likely alternative diagnosis. This could compromise horse welfare due to the commencement of lifelong therapy and/or failing to identify and treat an alternative potentially life-threatening condition. (B) Interpretation of diagnostic tests: (i) There is a significant effect of breed on plasma ACTH concentration, particularly in the autumn with markedly higher ACTH concentrations in some but not all 'thrifty' breeds; (ii) basal and/or post-TRH ACTH concentrations may also be affected by latitude/location, diet/feeding, coat colour, critical illness and trailer transport; (iii) mild pain is unlikely to have a large effect on basal ACTH, but caution may be required for more severe pain; (iv) determining diagnostic thresholds that allow for all possible contributory factors is not practical; therefore, the use of equivocal ranges is supported; (v) dynamic insulin testing and TRH stimulation testing may be combined, but TRH stimulation testing should not immediately follow an oral sugar test; (vi) equids with PPID and hyperinsulinaemia appear to be at higher risk of laminitis, but ACTH is not an independent predictor of laminitis risk. (C) Pharmacologic treatments and other treatment/management options: (i) Pergolide improves most clinical signs associated with PPID in the majority of affected animals; (ii) Pergolide treatment lowers basal ACTH concentrations and improves the ACTH response to TRH in many animals, but measures of insulin dysregulation (ID) are not altered in most cases; (iii) chasteberry has no effect on ACTH concentrations and there is no benefit to adding chasteberry to pergolide therapy; (iv) combination of cyproheptadine with pergolide is not superior to pergolide alone; (v) there is no evidence that pergolide has adverse cardiac effects in horses; (vi) Pergolide does not affect insulin sensitivity. (D) Monitoring pergolide-treated cases: (i) Hormone assays provide a crude indication of pituitary control in response to pergolide therapy, however it is unknown whether monitoring of ACTH concentrations and titrating of pergolide doses accordingly is associated with improved endocrinological or clinical outcome; (ii) it is unknown whether monitoring the ACTH response to TRH or clinical signs is associated with an improved outcome; (iii) there is very weak evidence to suggest that increasing pergolide dose in autumn months may be beneficial; (iv) there is little advantage in waiting for more than a month to perform follow-up endocrine testing following initiation of pergolide therapy; there may be merit in performing repeat tests sooner; (v) timing of sampling in relation to pergolide dosing does not confound measurement of ACTH concentration; (vi) there is no evidence that making changes after interpretation of ACTH concentrations measured at certain times of the year is associated with improved outcomes; (vii) evidence is very limited, however, compliance with PPID treatment appears to be poor and it is unclear whether this influences clinical outcome; (viii) evidence is very limited, but horses with clinical signs of PPID are likely to shed more nematode eggs than horses without clinical signs of PPID; it is unclear whether this results in an increased risk of parasitic disease or whether there is a need for more frequent assessment of faecal worm egg counts. MAIN LIMITATIONS: Limited relevant publications in the veterinary scientific literature. CONCLUSIONS: These findings should be used to inform decision-making in equine primary care practice.

Field study examining the mucosal microbiome in equine glandular gastric disease.

Equine glandular gastric disease (EGGD) is a common disease among athletic horses that can negatively impact health and performance. The pathophysiology of this EGGD remains poorly understood. Previous studies using controlled populations of horses identified differences in the gastric glandular mucosal microbiome associated with disease. The objective of this study was to compare the gastric microbiome in horses with EGGD and those without across multiple barns and differing management practices. We hypothesized that alterations in the microbiome of the gastric glandular mucosa are associated with EGGD. A secondary objective was to perform a risk factor analysis for EGGD using the diet and management data collected. Microbial populations of biopsies from normal pyloric mucosa of horses without EGGD (control biopsies), normal pyloric mucosa of horses with EGGD (normal biopsies) and areas of glandular mucosal disruption in horses with EGGD (lesion biopsies) were compared. Lesion biopsies had a different microbial community structure than control biopsies. Control biopsies had a higher read count for the phylum Actinomycetota compared to lesion biopsies. Control biopsies also had an enrichment of the genera Staphylococcus and Lawsonella and the species Streptococcus salivarius. Lesion biopsies had an enrichment of the genera Lactobacillus and Actinobacillus and the species Lactobacillus equigenerosi. These results demonstrate differences in the gastric glandular microbiome between sites of disrupted mucosa in horses with EGGD compared to pyloric mucosa of horses without EGGD. Risk factor analysis indicated that exercise duration per week was a risk factor for EGGD.

Characterization of gastrointestinal inflammatory cell type in equine glandular gastric disease.

OBJECTIVE: To compare small intestinal inflammation with gastric inflammation in horses with and without equine gastric glandular disease (EGGD), we evaluated endoscopic, macroscopic, and microscopic findings of the glandular stomach and microscopic findings of the small intestine. ANIMALS: 36 horses. METHODS: Horses underwent endoscopy and were scored for EGGD. After euthanasia, stomachs were collected and macroscopically evaluated. Normal pyloric mucosa, glandular lesions, and small intestinal (duodenum, mid-jejunum, and ileum) samples were collected and processed for microscopic examination. Cellular infiltrate was scored. Immunohistochemistry (CD3, CD20, and Iba-1) was performed on the ventral pylorus and small intestine of horses with mild to moderate lymphoplasmacytic infiltrate. A Spearman's correlation coefficient was used to evaluate the relationship of EGGD grade with gastric glandular inflammation, and the relationships of cellular infiltrate type and severity among glandular stomach, duodenum, jejunum, and ileum. RESULTS: Gastrointestinal inflammation was common, with gastric inflammatory infiltrate identified in 92%, duodenal inflammatory infiltrate in 83%, jejunal inflammatory infiltrate in 92%, and ileal inflammatory infiltrate in 92% of horses. Endoscopic evidence of gastric disease (hyperemia or EGGD grade ≥ 2/4) was not associated with the presence or severity of duodenal, jejunal, or ileal inflammation. Gastric lymphoplasmacytic inflammation grade ≥ 2 was associated with duodenal lymphoplasmacytic inflammation grade ≥ 2. This was a convenience sample of horses presenting for euthanasia. Medical history (including deworming history) was unknown. CLINICAL RELEVANCE: Gastric lymphoplasmacytic inflammation is associated with duodenal lymphoplasmacytic inflammation but not more distal small intestinal inflammation. Intestinal inflammation is not associated with endoscopic findings (hyperemia or EGGD grade ≥ 2/4).

Dietary and management factors influence the equine gastric microbiome.

OBJECTIVE: The purpose of this study was to characterize the relationship of diet and management factors with the glandular gastric mucosal microbiome. We hypothesize that the gastric mucosal microbial community is influenced by diet and management factors. Our specific objective is to characterize the gastric mucosal microbiome in relation to these factors. ANIMALS: 57 client-owned horses in the southern Louisiana region with and without equine glandular gastric disease. PROCEDURES: Diet and management data were collected via a questionnaire. Gastroscopy was used for evaluation of equine gastric ulcer syndrome and collection of glandular mucosal pinch biopsies. 16S rRNA amplicon sequencing was used for microbiome analysis. Similarity and diversity indices and sequence read counts of individual taxa were compared between diet and management factors. RESULTS: Differences were detected in association with offering hay, type of hay, sweet feed, turnout, and stalling. Offering hay and stalling showed differences in similarity indices, whereas hay type, sweet feed, and turnout showed differences in similarity and diversity indices. Offering hay, hay type, and sweet feed were also associated with differences in individual sequence read counts. CLINICAL RELEVANCE: This study provides preliminary characterization of the complex relationship between the glandular gastric microbiome and diet/management factors. The ideal microbiome to promote a healthy glandular gastric environment remains unknown.

Teaching veterinary surgical skills: Comparison of massed versus spaced instruction.

OBJECTIVE: To determine the effect of massed instruction (MI) versus spaced instruction (SI) of veterinary surgical skills on students' cognitive load and skill retention. STUDY DESIGN: Prospective randomized cohort study STUDY POPULATION: First-year veterinary students from Louisiana State University (LSU; n = 47) and Lincoln Memorial University (LMU; n = 101). METHODS: Students were randomized to MI (two skills in a single session of twice the duration) or SI (one skill per session on two consecutive days). Instructors, instructional ratio, and total educational time was equivalent. Following instruction, students completed a cognitive load questionnaire and underwent a structured assessment immediately after (LMU only), 1 day after, and 3-4 weeks after learning the second skill. Students completed two supervised practice sessions one and 2 weeks after the initial laboratory session(s). RESULTS: Overall cognitive load did not differ between groups (p > .05), although LMUs MI group reported higher physical and time demands, effort, and frustration. At initial assessment, SI students scored higher than MI students for the first skill at both LSU (mean checklist score = 27.7 vs. mean = 24; p = .004) and LMU (mean global rating score = 4.76 vs. mean = 4.55; p = .029). Differences between groups were no longer evident by 3-4 weeks after instruction. CONCLUSION: SI may lead to improved immediate performance; however, supervised practice was sufficient to overcome the initial disparity. CLINICAL SIGNIFICANCE: SI may be beneficial for initial skill performance. However, SI and MI students had similar performance after 3 weeks, suggesting the more convenient curricular design of MI may be sufficient as long as practice sessions are incorporated.

Approaches to endocrinopathic laminitis in the field: Results of a survey of veterinary practitioners in North America.

Endocrinopathic laminitis is the most common cause of laminitis in the field. Insulin has recently been implicated as a key factor in development of endocrinopathic laminitis; however, it is unclear whether diagnostic, and treatment approaches reflect insights derived from recent research. This study sought to evaluate North American veterinary practitioners' approach to endocrinopathic laminitis in the field. Demographic information, approach to diagnosis, management, and prognosis of endocrinopathic laminitis, as well as factors influencing changes in approach to laminitis were collected. To compare regional differences in approach to laminitis, results were compared to a recently published study from the United Kingdom. Findings of the present study suggest that North American practitioners have changed their approach to laminitis to more readily incorporate diagnostic testing for endocrine disease.

Building Clinical Skills Teaching Materials: A Study of Cognitive Task Analysis Versus Free Recall Instruction to Teach Canine Indirect Ophthalmoscopy.

Ophthalmoscopy is a core component of a complete ophthalmic examination. Due to its complex technical aspects and patients becoming uncooperative if the procedure is prolonged, it can be a difficult skill for a novice to learn and develop proficiency in. Skills instruction is typically provided by subject matter experts (SMEs) through free recall without an agreed-upon instructional framework. This can lead to unintentional omission of essential steps and knowledge required to perform skills correctly. Cognitive task analysis (CTA) allows for construction of standardized instructional protocols that encompass the knowledge and skills experts apply when performing tasks. The objectives of this study were to (a) develop a CTA-based teaching protocol for canine indirect ophthalmoscopy and (b) compare the steps verbalized or demonstrated by SMEs during free recall instruction versus those ultimately identified by CTA. Four SMEs participated in free recall instructional sessions and interviews used for the development of a CTA-based teaching protocol for novice learners. The CTA-based protocol identified 66 steps and sub-steps considered essential for successfully performing canine indirect ophthalmoscopy. During instructional sessions, SMEs on average failed to verbalize 57.1% of clinical knowledge steps, did not verbalize or demonstrate 68.3% and 9.5% of action steps, and did not verbalize or demonstrate 73.2% and 40.4% of decision steps, respectively. This study demonstrates that SMEs teaching indirect ophthalmoscopy by free recall may unintentionally omit important steps, suggesting that compared with free recall, CTA may generate more comprehensive and thus potentially more effective instructional materials for teaching technical skills in veterinary medicine.

Gastric microbiome in horses with and without equine glandular gastric disease.

BACKGROUND: The role of the gastric microbiome in development or persistence of equine glandular gastric disease (EGGD) remains to be investigated. HYPOTHESIS/OBJECTIVES: The objective was to characterize the glandular mucosal and gastric fluid microbiomes of horses with and without EGGD. It was hypothesized that differences in the mucosal microbiome are associated with EGGD. ANIMALS: Twenty-four horses were enrolled. METHODS: Gastroscopy was performed and EGGD scores recorded (score 0, n = 6; score 1, n = 8; score ≥2, n = 10). Gastric fluid and pinch biopsies of healthy glandular mucosa and EGGD lesions were collected via gastroscope. 16S rRNA amplicon sequencing of the gastric fluid and glandular mucosal biopsies was performed. Relationships between gastric fluid and mucosal microbial community composition were evaluated among EGGD score groups (EGGD 0-BX, EGGD 1-BX, EGGD ≥2-BX) and among endoscopic appearances: controls from horses without EGGD and normal areas, hyperemic areas, and lesions from horses with EGGD. RESULTS: Microbial community structure of mucosal biopsies differed among EGGD score groups (Jaccard similarity index; P = .009). Principal coordinate analysis showed separate clusters for EGGD 0-BX and EGGD ≥2-BX. CONCLUSIONS AND CLINICAL IMPORTANCE: A modest difference was detected in the community structure of the gastric glandular mucosal microbiome in association with EGGD score.

Development of and Validity Evidence for a Canine Ocular Model for Training Novice Veterinary Students to Perform a Fundic Examination.

Indirect fundoscopy is challenging for novice learners, as patients are often intolerant of the procedure, impeding development of proficiency. To address this, we developed a canine ocular simulator that we hypothesized would improve student learning compared to live dogs. Six board-certified veterinary ophthalmologists and 19 second-year veterinary students (novices) performed an indirect fundic examination on the model and live dog. Prior to assessment, novices were introduced to the skill with a standardized teaching protocol and practiced (without feedback) with either the model (n = 10) or live dog (n = 9) for 30 minutes. All participants evaluated realism and usefulness of the model using a Likert-type scale. Performance on the live dog and model was evaluated in all participants using time to completion of task, performance of fundic examination using a checklist and global score, identification of objects in the fundus of the model, and evaluation of time spent looking at the fundus of the model using eye tracking. Novices (trained on simulator or live dogs) were compared in fundic examination performance on the live dog and identification of shapes in the model. In general, experts performed the fundic examination faster (p ≤ .0003) and more proficiently than the novices, although there were no differences in eye tracking behavior between groups (p ≥ .06). No differences were detected between training on simulator versus live dog in development of fundoscopy skills in novices (p ≥ .20). These findings suggest that this canine model may be an effective tool to train students to perform fundoscopy.

Impact of concurrent treatment with omeprazole on phenylbutazone-induced equine gastric ulcer syndrome (EGUS).

BACKGROUND: Phenylbutazone is commonly prescribed for treatment of various painful or inflammatory disorders in horses, but is associated with gastrointestinal (GI) adverse effects. Anecdotally, many practitioners prescribe omeprazole concurrently with phenylbutazone to reduce development of equine gastric ulcer syndrome (EGUS), but the efficacy and safety of this practice remains unknown. OBJECTIVES: To evaluate the effect of omeprazole on phenylbutazone-induced equine glandular gastric disease (EGGD) and equine squamous gastric disease (ESGD). STUDY DESIGN: Randomised block experimental design. METHODS: Twenty-two horses with EGGD and ESGD scores ≤2 were included. Horses were assigned to treatment groups: phenylbutazone (4.4 mg/kg PO q 12 h; PBZ), phenylbutazone plus omeprazole (4 mg/kg PO q. 24 h; PBZ/OME) or placebo (CON) in a randomised block design based upon initial EGGD score. Horses were treated for up to 14 days. Gastroscopy was performed weekly; CBC and biochemistry were performed at Day 0 and study end. Horses were monitored for signs of colic and/or diarrhoea. RESULTS: EGGD score increased in PBZ (median change 1, inter-quartile range, [IQR], 0-2) compared to PBZ/OME (median change 0, IQR -1 to 0; P = .05). PBZ/OME (6/8) had more intestinal complications than CON (0/6; difference between proportions = 75%; 95% CI, 23%-93%; P = .03). Plasma protein concentrations decreased in PBZ, compared to CON (mean difference between groups, 14 g/L; 95% CI, 1.04-27; P = .03). Five horses were withdrawn from the study due to intestinal complications (n = 3 PBZ/OME and n = 2 PBZ); one horse (PBZ) was withdrawn due to severe grade 4 EGGD. MAIN LIMITATIONS: Small sample size and changes in management for the 2-3 days prior to study initiation; variable treatment duration among groups due to development of complications. CONCLUSIONS: Administration of omeprazole ameliorated PBZ-induced EGGD, but was associated with an increase in intestinal complications. Caution should be exercised when co-prescribing NSAIDs and omeprazole in horses, particularly in association with change in management.

Equine glandular gastric disease: prevalence, impact and management strategies.

Equine glandular gastric disease (EGGD) is an increasingly recognized disease of the glandular mucosa of the equine stomach. Diagnosis is confirmed by gastric endoscopy and scored based upon one of several different endoscopic scoring systems. Prevalence appears to be variable, depending upon breed and discipline. Primary identified risk factors include exercise frequency, and stress; therefore, management strategies are focused on reducing exercise and stress. Limiting grain intake and increasing pasture turnout may also be helpful preventative measures. Pharmacologic treatment consists primarily of an approved omeprazole product with or without misoprostol or sucralfate. Further research into the pathophysiology of EGGD may allow for identification of other targeted treatments.

Prevalence of and risk factors for equine glandular and squamous gastric disease in polo horses.

The objectives of this study were to determine the prevalence rates and risk factors for equine glandular gastric disease (EGGD) and equine squamous gastric disease (ESGD) in a population of 63 polo horses in competition. The prevalence of EGGD grade ≥ 1 was 69% and EGGD ≥ 2 was 31%. The prevalence of ESGD grade ≥ 1 was 54% and grade ≥ 2 was 37%. The risk factors retained in the final multivariable models were years of experience in polo competition for EGGD grade ≥ 1 and for grade ≥ 2, with decreased experience being associated with EGGD and weekly exercise duration and non-steroidal anti-inflammatory drug (NSAID) use being associated with ESGD grade ≥ 1. Decreasing weekly exercise duration was the only risk factor associated with ESGD grade ≥ 2. Equine gastric disease was common in this population of polo horses and the amount of experience and weekly exercise duration were related to the risk of disease.

Prévalence de la maladie gastrique glandulaire et squameuse des équidés et facteurs de risque chez les chevaux de polo. Les objectifs de cette étude consistaient à déterminer les taux de prévalence et les facteurs de risque pour la maladie gastrique glandulaire équine (MGGE) et la maladie gastrique squameuse équine (MGSE) dans une population de 63 chevaux de polo de compétition. La prévalence de la MGGE de grade ≥ 1 était de 69 % et de la MGGE ≥ 2 était de 31 %. La prévalence de la MGSE de grade ≥ 1 était de 54 % et de grade ≥ 2 était de 37 %. Les facteurs de risque conservés dans les modèles multivariables finaux étaient des années d'expérience dans les compétitions de polo pour la MGGE de grade ≥ 1 et de grade ≥ 2, et une expérience réduite était associée à la MGGE et la durée de l'exercice hebdomadaire et l'usage d'anti-inflammatoires non stéroïdiens (AINS) étaient associés à la MGSE de grade ≥ 1. La réduction de l'exercice hebdomadaire était le seul facteur de risque associé à la MGSE de grade ≥ 2. La maladie gastrique équine est commune dans cette population de chevaux de polo et la quantité d'expérience et la durée de l'exercice hebdomadaire étaient associées au risque de maladie.(Traduit par Isabelle Vallières).

Comparison of two methods for measurement of equine adrenocorticotropin.

Accurate measurement of equine adrenocorticotropin (ACTH) is important for the diagnosis of equine pituitary pars intermedia dysfunction (PPID). Several radioimmunoassays (RIAs) and chemiluminescent immunoassays (CIAs) are used for measurement of ACTH concentration in horses; whether these methods yield similar results across a range of concentrations is not determined. We evaluated agreement between a commercial RIA and CIA. Archived plasma samples ( n = 633) were measured with both assays. Correlation between the 2 methods was moderate ( r = 0.49, p < 0.001). Bland-Altman analysis revealed poor agreement, with a proportional bias and widening limits of agreement with increasing values. Poor agreement between assays was also observed when evaluating plasma samples with concentrations at or below the recommended diagnostic cutoff value for PPID testing. The lack of agreement suggests that measurements obtained should not be considered interchangeable between methods.

Relationship of skeletal muscle inflammation with obesity and obesity-associated hyperinsulinemia in horses.

Local (skeletal muscle and adipose) and systemic inflammation are implicated in the development of obesity-associated insulin resistance in humans. In horses, obesity is neither strongly nor consistently associated with systemic inflammation. The role of skeletal muscle inflammation in the development of insulin dysregulation (insulin resistance or hyperinsulinemia) remains to be determined. We hypothesized that skeletal muscle inflammation is related to obesity-associated hyperinsulinemia in horses. Thirty-five light-breed horses with body condition scores (BCSs) of 3/9 to 9/9 were studied, including 7 obese, normoinsulinemic (BCS ≥ 7, resting serum insulin < 30 µIU/mL) and 6 obese, hyperinsulinemic (resting serum insulin ≥ 30 µIU/mL) horses. Inflammatory biomarkers were evaluated in skeletal muscle biopsies and plasma. Relationships between markers of inflammation and BCS were evaluated. To assess the role of inflammation in obesity-associated hyperinsulinemia, markers of inflammation were compared among lean or ideal, normoinsulinemic (L-NI); obese, normoinsulinemic (O-NI); and obese, hyperinsulinemic (O-HI) horses. Skeletal muscle and plasma tumor necrosis factor alpha (TNFα) concentrations were negatively correlated with BCS. When comparing inflammatory markers among groups, skeletal muscle TNFα was lower in the O-HI group than in the O-NI or L-NI groups. In horses, neither skeletal muscle nor systemic inflammation appears to be positively related to obesity or obesity-associated hyperinsulinemia.

L'inflammation locale (muscle squelettique et tissu adipeux) et systémique sont impliquées dans le développement de la résistance à l'insuline associée à l'obésité chez l'humain. Chez les chevaux, l'obésité n'est pas fortement ou de manière constante associée avec l'inflammation systémique. Le rôle de l'inflammation des muscles squelettiques dans le développement de la dérégulation de l'insuline (résistance à l'insuline ou hyper-insulinémie) reste à être déterminé. Nous avons émis l'hypothèse que chez les chevaux l'inflammation des muscles squelettiques est reliée à l'hyper-insulinémie associée à l'obésité. Trente-cinq chevaux de race légère avec des pointages de condition corporelle (PCCs) variant de 3/9 à 9/9 ont été étudiés, incluant sept chevaux obèses, normo-insulinémique (PCC ≥ 7, insuline sérique au repos < 30 µUI/mL) et six chevaux obèses, hyper-insulinémique (insuline sérique au repos ≥ 30 µUI/mL). Les biomarqueurs de l'inflammation ont été évalués dans des biopsies de muscles squelettiques et le plasma. Les relations entre les marqueurs de l'inflammation et le PCC ont été évaluées. Pour apprécier le rôle de l'inflammation dans l'hyper-insulinémie associée à l'obésité, les marqueurs de l'inflammation ont été comparés parmi les chevaux élancés ou idéal, normo-insulinémique (L-NI); les chevaux obèses, normo-insulinémique (O-NI); et les chevaux obèses, hyperinsulinémique (O-HI). Les concentrations du facteur nécrosant des tumeurs alpha (TNFα) étaient corrélées négativement avec le PCC. Lors de la comparaison des marqueurs de l'inflammation entre les groupes, la concentration de TNFα dans les muscles squelettiques était plus basse dans le groupe O-HI que dans les groupes O-NI ou L-NI. Chez les chevaux, ni l'inflammation systémique ou celle des muscles squelettiques ne semblent reliées positivement à l'obésité ou à l'hyper-insulinémie associée à l'obésité.(Traduit par Docteur Serge Messier).

Relationship of oxidative stress in skeletal muscle with obesity and obesity-associated hyperinsulinemia in horses.

In horses, hyperinsulinemia and insulin resistance (insulin dysregulation) are associated with the development of laminitis. Although obesity is associated with insulin dysregulation, the mechanism of obesity-associated insulin dysregulation remains to be established. We hypothesized that oxidative stress in skeletal muscle is associated with obesity-associated hyperinsulinemia in horses. Thirty-five light breed horses with body condition scores (BCS) of 3/9 to 9/9 were studied, including 7 obese, normoinsulinemic (BCS ≥ 7, resting serum insulin < 30 µIU/mL) and 6 obese, hyperinsulinemic (resting serum insulin ≥ 30 µIU/mL) horses. Markers of oxidative stress (oxidative damage, mitochondrial function, and antioxidant capacity) were evaluated in skeletal muscle biopsies. A Spearman's rank correlation coefficient was used to determine relationships between markers of oxidative stress and BCS. Furthermore, to assess the role of oxidative stress in obesity-related hyperinsulinemia, markers of antioxidant capacity and oxidative damage were compared among lean, normoinsulinemic (L-NI); obese, normoinsulinemic (O-NI); and obese, hyperinsulinemic (O-HI) horses. Increasing BCS was associated with an increase in gene expression of a mitochondrial protein responsible for mitochondrial biogenesis (estrogen-related receptor alpha, ERRα) and with increased antioxidant enzyme total superoxide dismutase (TotSOD) activity. When groups (L-NI, O-NI, and O-HI) were compared, TotSOD activity was increased and protein carbonyls, a marker of oxidative damage, decreased in the O-HI compared to the L-NI horses. These findings suggest that a protective antioxidant response occurred in the muscle of obese animals and that obesity-associated oxidative damage in skeletal muscle is not central to the pathogenesis of equine hyperinsulinemia.

Chez les chevaux l'hyperinsulinémie et la résistance à l'insuline (dérèglement de l'insuline) sont associées avec le développement de fourbure. Bien que l'obésité soit associée avec le dérèglement de l'insuline, le mécanisme de l'obésité associée au dérèglement de l'insuline demeure à être établi. Nous émettons l'hypothèse que le stress oxydatif dans les muscles squelettiques est associé avec l'obésité associée à l'hyperinsulinémie chez les chevaux. Trente-cinq chevaux de races légères avec des pointages de conditions corporelles (PCC) de 3/9 à 9/9 ont été étudiés, incluant sept chevaux obèses, normo-insulinémique (PCC ≥ 7, insuline sérique au repos < 30 µIU/mL) et six chevaux obèses, hyperinsulinémique (insuline sérique au repos ≥ 30 µIU/mL). Les marqueurs de stress oxydatif (damage oxydatif, fonction mitochondriale, et capacité antioxydante) furent évalués dans des biopsies de muscles squelettiques. Un coefficient de corrélation de rang de Spearman a été utilisé pour déterminer la relation entre les marqueurs de stress oxydatif et le PCC. De plus, pour évaluer le rôle du stress oxydatif dans l'obésité reliée à l'hyperinsulinémie, les marqueurs de la capacité anti-oxydante et des dommages oxydatifs ont été comparés entre des chevaux minces, normo-insulinémiques (L-NI); des chevaux obèses, normo-insulinémique (O-NI); et des chevaux obèses, hyperinsulinémiques (O-HI). Une augmentation des PCCs était associée avec une augmentation de l'expression des gènes d'une protéine mitochondriale responsable de la biogénèse des mitochondries (récepteur alpha apparenté aux estrogènes, ERRα) et d'une augmentation de l'activité anti-oxydante totale de l'enzyme superoxyde dismutase (TotSOD). Lors de la comparaison des groupes (L-NI, O-NI, et O-HI), l'activité TotSOD était augmentée et les carbonyles protéiques, un marqueur des dommages oxydatifs, avaient diminué chez les chevaux O-HI comparativement aux chevaux L-NI. Ces données suggèrent qu'une réponse anti-oxydante protectrice s'est produite dans le muscle des chevaux obèses et que le dommage oxydatif associés à l'obésité dans les muscles squelettiques n'est pas central à la pathogénèse de l'hyperinsulinémie équine.(Traduit par Docteur Serge Messier).

Comparison of two methods for measurement of equine insulin.

Diagnosis of equine hyperinsulinemia requires an accurate method for quantification of equine insulin concentrations. The objectives of the current study were to compare 2 commercially available techniques for measurement of equine insulin, the radioimmunoassay (RIA) and chemiluminescent immunoassay (CIA). Recovery was poor for both assays, but worse for the CIA. Serial dilution of a high endogenous insulin sample yielded better linearity for the RIA ( r2 = 0.99, P < 0.001) than the CIA ( r2 = 0.92, P = 0.009). Bland-Altman analysis indicated that the CIA was, on average, 91 pmol/l higher than the RIA, with wide limits of agreement (95% limits of agreement: -508 to 691 pmol/l). These findings suggest that results between the assays should not be considered interchangeable.

Gastric and enteric phytobezoars caused by ingestion of persimmon in equids.

CASE DESCRIPTION-13 equids (10 horses, 2 donkeys, and 1 pony) were examined for signs of colic (n = 7), weight loss (6), anorexia (3), and diarrhea (2). Ten equids were evaluated in the fall (September to November). Seven equids had a history of persimmon ingestion. CLINICAL FINDINGS-A diagnosis of phytobezoar caused by persimmon ingestion was made for all equids. Eight equids had gastric persimmon phytobezoars; 5 had enteric persimmon phytobezoars. Gastroscopy or gastroduodenoscopy revealed evidence of persimmon ingestion in 8 of 10 equids in which these procedures were performed. TREATMENT AND OUTCOME-2 of 13 equids were euthanatized prior to treatment. Supportive care was instituted in 11 of 13 equids, including IV administration of fluids (n = 8) and treatment with antimicrobials (5), NSAIDs (5), and gastric acid suppressants (4). Persimmon phytobezoar-specific treatments included dietary modification to a pelleted feed (n = 8); oral or nasogastric administration of cola or diet cola (4), cellulase (2), or mineral oil (2); surgery (4); and intrapersimmon phytobezoar injections with acetylcysteine (1). Medical treatment in 5 of 7 equids resulted in resolution of gastric persimmon phytobezoars. Seven of 8 equids with gastric persimmon phytobezoars and 1 of 5 equids with enteric persimmon phytobezoars survived > 1 year after hospital discharge. CLINICAL RELEVANCE-Historical knowledge of persimmon ingestion in equids with gastrointestinal disease warrants gastroduodenoscopy for evaluation of the presence of persimmon phytobezoars. In equids with gastric persimmon phytobezoars, medical management (including administration of cola or diet cola and dietary modification to a pelleted feed) may allow for persimmon phytobezoar dissolution.

Assessment of serum antibody titers against canine distemper virus, canine adenovirus type II, and canine parvovirus in Alaskan sled dogs before and after a long-distance race.

OBJECTIVE: To determine serum antibody titers against canine distemper virus (CDV), canine adenovirus type II (CAV-2), and canine parvovirus (CPV) in trained sled dogs prior to and after completion of a long-distance race. DESIGN: Prospective cohort study. ANIMALS: 195 Alaskan sled dogs (from 18 kennels) that participated in the 2006 Iditarod Trail Race. PROCEDURES: All 1,323 dogs participating in the race had been vaccinated against the 3 viruses at 19 to 286 days prior to initial blood sample collection (obtained within the month preceding the race). Within 12 hours of race completion, blood samples were collected from 195 dogs (convenience sample) and matched with each dog's prerace sample. Serum antibody titers (90% confidence intervals [CIs]) were determined via serum neutralization assays. RESULTS: After racing, geometric mean titers against CDV and CPV were significantly higher (2,495 [90% CI, 321 to 16,384] and 6,323 [90% CI, 512 to 32,768], respectively) than prerace values (82 [90% CI, 11 to 362] and 166 [90% CI, 32 to 1,024], respectively). Sixty-one of 194 (31.4%) dogs had > or = 4-fold increases in anti-CPV antibody titers after racing. Prerace serum antibody titers against CDV, CPV, and CAV-2 varied significantly by sled team but were not associated with time since vaccination. CONCLUSIONS AND CLINICAL RELEVANCE: Postrace increases in serum anti-CDV and anti-CPV antibody titer might reflect exposure of dogs to these agents immediately before or during racing. Dogs had no clinical signs of CDV-, CAV-2-, or CPV-associated disease; therefore, the clinical importance of these titer changes is uncertain.

Hydration status and water turnover of dogsled drivers during an endurance sled dog event in the arctic.

OBJECTIVES: To determine changes in common urinary markers of hydration maintained by the drivers (mushers) during a wilderness endurance event in the arctic and to determine water turnover in this select group of individuals. STUDY DESIGN: During this descriptive study, data was systematically collected on hydration, water turnover, changes in resting and exercise heart rate, fatigue and rating of perceived exertion during an arduous dogsled race in the arctic. METHODS: Sixteen mushers were recruited for the study, 13 of whom completed the entire race. At five different checkpoints along the 1049-mile trail (symbolic distance), urine was collected. Urine osmolality (U(osm)) was determined using freezing point depression. Urine specific gravity (U(sg)) was determined using a hand-held refractometer. Water turnover was measured in 5 mushers from rates of deuterium (2H2O) elimination (rH2O). Prior to the start of the race, and at five checkpoints along the trail, a resting heart rate, fatigue rating scale and a rating of perceived exertion (RPE), were collected. RESULTS: Out of the 13 subjects that completed the event, four of the mushers had a U(sg) > or = 1.030 (mean 1.023 +/- 0.007) at some point during the event. Ten had a urine osmolality > or = 900 mOsm L(-1) at some point during the event, with an average U(osm) of 868 +/- 277 mOsm L(-1) over the duration of the event. Water turnover demonstrated that rH2O averaged 2.85 +/- 1.18 ml kg(-1) day(-1) (range 2.03 -4.60) over the duration of the event. Resting heart rate increased significantly over the course of the race. The RPE was related to the overall fatigue rating scale. CONCLUSIONS: These data demonstrate that the majority of mushers studied showed signs of dehydration based on common urinary markers during the long-distance dogsled race. The dehydration appears to have had an influence on the resting heart rate, overall fatigue and the rating of perceived exertion during the race.