Adult Animal Stem Cell-Derived Organoids in Biomedical Research and the One Health Paradigm.

Preclinical biomedical research is limited by the predictiveness of in vivo and in vitro models. While in vivo models offer the most complex system for experimentation, they are also limited by ethical, financial, and experimental constraints. In vitro models are simplified models that do not offer the same complexity as living animals but do offer financial affordability and more experimental freedom; therefore, they are commonly used. Traditional 2D cell lines cannot fully simulate the complexity of the epithelium of healthy organs and limit scientific progress. The One Health Initiative was established to consolidate human, animal, and environmental health while also tackling complex and multifactorial medical problems. Reverse translational research allows for the sharing of knowledge between clinical research in veterinary and human medicine. Recently, organoid technology has been developed to mimic the original organ's epithelial microstructure and function more reliably. While human and murine organoids are available, numerous other organoids have been derived from traditional veterinary animals and exotic species in the last decade. With these additional organoid models, species previously excluded from in vitro research are becoming accessible, therefore unlocking potential translational and reverse translational applications of animals with unique adaptations that overcome common problems in veterinary and human medicine.

Effect of prewarmed crystalloid fluids and an in-line fluid warming device on fluid outflow temperatures at ambient temperatures of 21-22°C and 3.5°C.

Equine veterinarians frequently treat patients in non-climate-controlled (i.e., hospitalized) settings. In colder environments, intravenous (IV) fluid administration can contribute to patient hypothermia. The objective of this study was to evaluate three IV fluid warming mechanisms to determine their effect on fluid outflow temperatures at ambient temperatures of 21-22°C and 3.5°C. In this study, fluid outflow temperatures were measured using three warming mechanisms: (1) pre-warmed fluids at 42°C, (2) an in-line warming device placed 163 cm away from the Luer-lock fluid line adaptor (location 1) on the fluid line, and (3) an in-line warming device placed 88 cm away from the Luer-lock fluid line adaptor (location 2) on the fluid line. These warming mechanisms were compared to outflow temperatures measured using no warming mechanism at ambient temperatures of 21-22°C and 3.5°C with flow rates of ∼12 L/hour (gravity flow bolus) and 999 mL/hour. All outflow temperatures were measured with a thermistor. At ∼12L/hour, the use of pre-warmed fluids increased outflow temperatures at both ambient temperatures of 21-22°C and 3.5°C ambient temperatures and an in-line warming device placed at location 1 significantly increased outflow temperatures in 3.5°C ambient temperatures. At 999 mL/hour, use of pre-warmed fluids or an in-line warming device, placed at either location, increased outflow temperatures at ambient temperatures of 21°C or 3.5°C.

Survival rates and factors associated with survival and laminitis of horses with acute diarrhoea admitted to referral institutions.

BACKGROUND: Clinicopathological findings and their association with the outcome and development of laminitis in horses with acute diarrhoea has not been investigated in a multicentre study across different geographic regions. OBJECTIVES: Describe and compare clinicopathologic findings of diarrhoeic horses between different geographic regions, survival rates and factors associated with non-survival and laminitis. STUDY DESIGN: Multicentre retrospective case series. METHODS: Information from horses with acute diarrhoea presenting to participating institutions between 2016 and 2020 was collected, and clinicopathological data were compared between surviving and non-surviving horses and horses that did and did not develop laminitis. Survival rates and seasonal and geographic differences were also investigated. RESULTS: One thousand four hundred thirty-eight horses from 26 participating institutions from 4 continents were included; 76% survived to discharge with no differences identified between geographic regions. The survival proportion of horses with SIRS and creatinine concentrations > 159 µmol/L was 55% (154/279) compared with 81% (358/437) for those with SIRS and creatinine concentrations < 159 µmol/L (p < 0.001). The survival proportion of horses with SIRS that had an L-lactate concentration > 2.8 mmol/L was 59% (175/298) compared with 81% (240/296) in horses with SIRS and L-lactate concentration < 2.8 mmol/L (p < 0.001). The proportion of horses that developed laminitis was lower in Europe (4%, 19/479) compared with North America (8%, 52/619), Australia (8%, 12/138) and Latin America (11%, 16/146) (p < 0.05). More horses developed laminitis in the summer (46%, 39/85) compared with winter (18%, 15/85), spring (18%, 15/85) and fall (19%, 16/85) (p < 0.01). Horses with laminitis had greater odds of non-survival than those without laminitis (OR: 3.73, 95% CI: 2.47-5.65). MAIN LIMITATIONS: Not all variables were available for all horses due to the retrospective nature. CONCLUSIONS: Clinicopathological findings in horses with acute diarrhoea and their association with survival are similar across geographic regions. However, developing laminitis secondary to diarrhoea is less common in Europe. In addition, factors associated with non-survival were indicative of disease severity and subsequent cardiovascular compromise.

CONTEXTO: Achados clínico-patológicos e suas associações com o sobrevivência e desenvolvimento de laminite em cavalos com diarreia aguda não foram investigados em um estudo multicêntrico envolvendo diferentes regiões geográficas. OBJETIVOS: Descrever e comparar achados clínico-patológicos de cavalos com diarreia em diferentes regiões geográficas, taxa de sobrevivência e fatores associados com mortalidade e laminite. DELINEAMENTO DO ESTUDO: Estudo multicêntrico retrospectivo de série de casos. METODOLOGIA: Informação sobre equinos com diarreia aguda apresentados às instituições participantes entre 2016 e 2020 foram coletados, e dados clínico-patológicos foram comparados entre sobreviventes e não-sobreviventes, e cavalos que desenvolveram ou não laminite. Taxa de sobrevivência, e diferenças sazonais e geográficas também foram investigadas. RESULTADOS: 1438 cavalos de 26 instituições participantes de 4 continentes foram incluídos; 76% sobreviveram e receberam alta e nenhuma diferença foi observada entre as diferentes regiões geográficas. A proporção de cavalos que sobreviveram com SIRS e concentração de creatinina > 1.8 mg/dL foi 55% (154/279) comparado com 81% (358/437) dos cavalos com SIRS e concentração de creatinina < 1.8 mg/dL (p < 0.001). A proporção de cavalos com SIRS que tinham concentração de L-lactato > 2.8 mmol que sobreviveram foi 59% (175/298) comparado com 81% (240/296) dos cavalos com SIRS e concentração de L-lactato < 2.8 mmol/L (p < 0.001). A proporção de cavalos que desenvolveram laminite foi menor na Europa (4%, 19/479) comparado com a América do Norte (8%, 52/619), Austrália (8%, 12/138) e América Latina (11% 16/146) (p < 0.05). Mais cavalos desenvolveram laminite no verão (46%, 39/8) comparado com inverno (18%, 15/85), primavera (18%, 15/85) e outono (19%, 16/85) (p < 0.01). Cavalos com laminite tiveram chances maior de não sobreviver do que aqueles que não desenvolveram laminite (OR: 3.73, 95% CI: 2.47 a 5.65). PRINCIPAIS LIMITAÇÕES: Algumas variáveis não estavam disponíveis para alguns cavalos devido à natureza retrospectiva deste estudo. CONCLUSÕES: Achados clínico-patológicos em equinos com diarreia aguda e sua associação com sobrevivência é similar entre as diferentes regiões geográficas. Contudo, o desenvolvimento de laminite secundário à diarreia é menos comum na Europa. Além disso, fatores associados com não-sobrevivência foram indicativos de severidade da doença e subsequente comprometimento cardiovascular.

Diagnostic approaches, aetiological agents and their associations with short-term survival and laminitis in horses with acute diarrhoea admitted to referral institutions.

BACKGROUND: An international description of the diagnostic approaches used in different institutions to diagnose acute equine diarrhoea and the pathogens detected is lacking. OBJECTIVES: To describe the diagnostic approach, aetiological agents, outcome, and development of laminitis for diarrhoeic horses worldwide. STUDY DESIGN: Multicentre retrospective case series. METHODS: Information from horses with acute diarrhoea presenting to participating institutions between 2016 and 2020, including diagnostic approaches, pathogens detected and their associations with outcomes, were compared between institutions or geographic regions. RESULTS: One thousand four hundred and thirty-eight horses from 26 participating institutions from 4 continents were included. Overall, aetiological testing was limited (44% for Salmonella spp., 42% for Neorickettsia risticii [only North America], 40% for Clostridiodes difficile, and 29% for ECoV); however, 13% (81/633) of horses tested positive for Salmonella, 13% (35/262) for N. risticii, 9% (37/422) for ECoV, and 5% (27/578) for C. difficile. C. difficile positive cases had greater odds of non-survival than horses negative for C. difficile (OR: 2.69, 95%CI: 1.23-5.91). In addition, horses that were positive for N. risticii had greater odds of developing laminitis than negative horses (OR: 2.76, 95%CI: 1.12-6.81; p = 0.029). MAIN LIMITATIONS: Due to the study's retrospective nature, there are missing data. CONCLUSIONS: This study highlighted limited diagnostic investigations in cases of acute equine diarrhoea. Detection rates of pathogens are similar to previous reports. Non-survival and development of laminitis are related to certain detected pathogens.

Comparison of Traditional Didactic vs. Additional Hands-on Simulation Training in the Performance of Basic Life Support in Veterinary Students - A Prospective, Blinded, Randomized Study.

Cardiopulmonary resuscitation (CPR) is a critical skill for veterinarians, but the most effective training methods and techniques are still unknown. In human medicine, simulation training enhances both knowledge and performance of basic life support CPR. This study evaluated the comparative effectiveness of didactic versus a combination of didactic and simulation training on performance and understanding of basic life support techniques in second-year veterinary medical students.

Equine Rotaviral Diarrhea.

Equine rotavirus is one of the most common causes of infectious diarrhea in foals. Although the infection itself is self-limiting, the resulting diarrhea is due to multiple mechanisms and can be severe, requiring supportive care including fluid and electrolyte support. Prompt diagnosis is important for treatment and biosecurity decisions and can be achieved by several means. Prevention, while imperfect, currently relies on vaccination of pregnant mares before parturition, ingestion of adequate colostrum from vaccinated mares and biosecurity measures.

The hypothalamic-pituitary-adrenal axis response to ovine corticotropin-releasing-hormone stimulation tests in healthy and hospitalized foals.

BACKGROUND: The hypothalamic-pituitary-adrenocortical axis (HPAA) response to sepsis can be impaired in critical illness. Corticotropin-releasing hormone (CRH) stimulation test might assess HPAA function in foals. OBJECTIVE: To evaluate plasma cortisol, ACTH, arginine vasopressin (AVP), and endogenous CRH (eCRH) response to different doses of ovine CRH (oCRH). ANIMALS: Healthy (n = 14) and hospitalized (n = 15) foals <7 days of age. METHODS: In this prospective randomized study, oCRH (0.1, 0.3, and 1 µg/kg) was administered intravenously and blood samples were collected before, 15, 30, 60, and 90 minutes after administration of oCRH to determine plasma hormone concentrations. The hormonal response was evaluated as the difference (Delta; µg/dL or pg/mL) or percent change between baseline hormone concentration and each time point after oCRH stimulation. RESULTS: Cortisol concentrations increased from baseline at 15 minutes with 0.1 and 0.3 µg/kg and at 30 and 60 minutes from baseline with 1 µg/kg oCRH (P < .05) in healthy and hospitalized foals. ACTH concentrations increased from baseline at 15 minutes with 0.1 µg/kg and at 30 minutes with 1 µg/kg oCRH (P < .05) in hospitalized foals. Delta cortisol 0 - 30, ACTH 0 - 30, and eCRH 0 - 30 was higher for the 1 µg/kg compared with 0.1 µg/kg oCRH in healthy foals (P < .05). Delta ACTH 0 - 15 and eCRH 0 - 30 was higher for the 1 µg/kg compared with the lower doses of oCRH in hospitalized foals (P < .05). CONCLUSIONS AND CLINICAL IMPORTANCE: Cortisol, ACTH, and eCRH concentrations increased in response to administration of all doses of oCRH. One microgram per kilogram of oCRH appears to be optimal for the assessment of HPAA in healthy and hospitalized foals.

Acquisition and use of analgesic drugs by horse owners in the United States.

BACKGROUND: Little is known about the acquisition and use of equine analgesic drugs by horse owners in the United States (US). OBJECTIVES: To determine factors associated with possession of analgesic drugs by horse owners in the US or with analgesic drug acquisition from sources noncompliant with a valid veterinarian-client-patient (VCPR) relationship. STUDY DESIGN: Cross-sectional survey. METHODS: An internet-based questionnaire included items related to experiences with horses and equine analgesic drugs. Factors associated with possession of ≥5 types of analgesic drugs and with the acquisition of drugs from VCPR noncompliant sources were analysed using logistic regression. RESULTS: Responses from 389 US horse owners indicated that 96% have access to at least one type of equine analgesic medication and most are confident in their drug administration skills. Horse owners with ≥5 types of analgesic drugs were more likely to have managed >20 horses in their life (odds ratio [OR] = 3.1, 95% confidence interval [CI] = 1.7-5.6), have medical insurance for some horses (OR = 4.2, CI = 2.3-7.7), and have veterinary or human medical training (OR = 2.2, CI = 1.2-4.1) and were less likely to have a primary care veterinarian requiring >30 minutes travel time (OR = 0.5, CI = 0.3-0.9). Horse owners who obtained drugs through VCPR noncompliant sources were likely to be male (OR = 5.6, CI = 1.6-19.4), ≤40 years of age (OR = 2.0, CI = 1.2-3.2), and reside in the South or West regions of the US (OR = 2.4, CI = 1.4-4.0). MAIN LIMITATIONS: Possible distribution, self-selection, response, and recall biases as a result of convenience sampling methodology. CONCLUSIONS: Discussion between veterinarians and horse owners regarding available analgesic drugs and owners' competence in administering those drugs may improve veterinary care recommendations and owner compliance.

HISTORIAL: Poco se sabe sobre la obtención y uso de medicamentos analgésicos para equinos usados por dueños de caballos en los Estados Unidos (EE. UU.). OBJETIVOS: Determinar los factores asociados con la posesión de medicamentos analgésicos por dueños de caballos en los EE. UU. o con la obtención de medicamentos analgésicos de fuentes que no cumplen con una relación valida veterinario-cliente-paciente (VCPR). DISEÑO DEL ESTUDIO: Estudio sectorial. MÉTODOS: Un cuestionario en línea incluyo puntos relacionados con experiencias con caballos y medicamentos analgésicos para equinos. Los factores asociados con la posesión de ≥5 tipos de analgésicos y con la obtención de medicamentos que no cumplen con fuentes VCPR fueron analizados usando regresión logística. RESULTADOS: Las respuestas de 389 dueños americanos de caballos. indicaron que el 96% tiene acceso a por lo menos un tipo de medicamento analgésico equino y la mayoría está seguro de su capacidad de administrar este medicamento. Los dueños de caballos con >5 tipos de medicamentos analgésicos tenían la tendencia de manejar a más de > 20 caballos en su vida (razón de momios [OR]=3.1, 95% intervalo de confianza [CI]=1.7-5.6), tienen seguro médico para algunos de los caballos (OR=4.2, CI=2.3-7.7), y tienen entrenamiento veterinario o medico humano (OR=2.2, CI=1.2-4.1) y tenían menor posibilidad de necesitar cuidado veterinario primario con > 30 minutos de tiempo de viaje (OR=0.5, CI=0.3-0.9). Los dueños de caballos que obtuvieron medicamentos a través de una fuente que no cumplía VCPR tenían tendencia a ser hombres (OR=5.6, CI=1.6-19.4), tener < 40 años de edad (OR=2.0, CI=1.2-3.2), y residir en las regiones del Sur o Oeste de los EEUU (OR=2.4, CI= 1.4-4,0). LIMITACIONES PRINCIPALES: Posible sesgo de distribución, autoselección, respuesta y recuerdos como resultado de una metodología de muestreo por conveniencia. CONCLUSIONES: Una discusión entre veterinarios y dueños de caballos al respecto de los analgésicos disponibles y la competencia de los dueños en administrar estos medicamentos podría mejorar las recomendaciones de cuidados veterinarios y el cumplimiento de los dueños.

Equine Probiotics-What Are They, Where Are We and Where Do We Need To Go?

Probiotics are live microorganisms that when consumed in adequate amounts confer a health benefit to the host. The objective of this review is to critically evaluate the definition of probiotics with reference to their use as supplements in horses, research regarding quality control, and propose areas for future focus. Several studies, performed over a 19-year period, have consistently identified deficiencies when comparing actual contents to label claims. Furthermore, basic information such as expiration dates and storage instructions are often missing from the labels. Finally, the authors will propose several criteria that consumers should consider when choosing probiotics marketed for use in horses.

Canine Intestinal Organoids in a Dual-Chamber Permeable Support System.

The permeable support system is typically used in conjunction with traditional two-dimensional (2D) cell lines as an in vitro tool for evaluating the oral permeability of new therapeutic drug candidates. However, the use of these conventional cell lines has limitations, such as altered expression of tight junctions, partial cell differentiation, and the absence of key nuclear receptors. Despite these shortcomings, the Caco-2 and MDCK models are widely accepted and validated for the prediction of human in vivo oral permeability. Dogs are a relevant translational model for biomedical research due to their similarities in gastrointestinal anatomy and intestinal microflora with humans. Accordingly, and in support of parallel drug development, the elaboration of an efficient and accurate in vitro tool for predicting in vivo drug permeability characteristics both in dogs and humans is highly desirable. Such a tool could be the canine intestinal organoid system, characterized by three-dimensional (3D), self-assembled epithelial structures derived from adult stem cells. The (1) Permeable Support Seeding Protocol describes the experimental methods for dissociating and seeding canine organoids in the inserts. Canine organoid isolation, culture, and harvest have been previously described in a separate set of protocols in this special issue. Methods for general upkeep of the canine intestinal organoid monolayer are discussed thoroughly in the (2) Monolayer Maintenance Protocol. Additionally, this protocol describes methods to assess the structural integrity of the monolayer via transepithelial electrical resistance (TEER) measurements and light microscopy. Finally, the (3) Permeability Experimental Protocol describes the tasks directly preceding an experiment, including in vitro validation of experimental results. Overall, the canine organoid model, combined with a dual-chamber cell culture technology, overcomes limitations associated with 2D experimental models, thereby improving the reliability of predictions of the apparent oral permeability of therapeutic drug candidates both in the canine and human patient.

Standardization and Maintenance of 3D Canine Hepatic and Intestinal Organoid Cultures for Use in Biomedical Research.

Dogs develop complex multifactorial diseases analogous to humans, including inflammatory diseases, metabolic diseases, and cancer. Therefore, they represent relevant large animal models with the translational potential to human medicine. Organoids are 3-dimensional (3D), self-assembled structures derived from stem cells that mimic the microanatomy and physiology of their organ of origin. These translational in vitro models can be used for drug permeability and discovery applications, toxicology assessment, and to provide a mechanistic understanding of the pathophysiology of multifactorial chronic diseases. Furthermore, canine organoids can enhance the lives of companion dogs, providing input in various areas of veterinary research and facilitating personalized treatment applications in veterinary medicine. A small group of donors can create a biobank of organoid samples, reducing the need for continuous tissue harvesting, as organoid cell lines can be sub-cultured indefinitely. Herein, three protocols that focus on the culture of intestinal and hepatic canine organoids derived from adult stem cells are presented. The Canine Organoid Isolation Protocol outlines methods to process tissue and embedding of the cell isolate in a supportive matrix (solubilized extracellular membrane matrix). The Canine Organoid Maintenance Protocol describes organoid growth and maintenance, including cleaning and passaging along with appropriate timing for expansion. The Organoid Harvesting and Biobanking Protocol describes ways to extract, freeze, and preserve organoids for further analysis.

Pain severity scores for common equine disorders as provided by horse owners and equine veterinarians.

BACKGROUND: Understanding factors influencing assessment of pain in horses will facilitate communication between veterinarians and horse owners. OBJECTIVES: To compare estimates of pain experienced by horses as provided by veterinarians and horse owners and to determine factors associated with individuals who perceive horses to be experiencing extreme pain or minimal pain. STUDY DESIGN: Cross-sectional study. METHODS: Internet-based questionnaires for horse owners and veterinarians included items related to recognition of pain in horses, estimated degree of pain experienced by horses, and demographic information. Variables associated with perception of a high or low degree of pain were investigated using logistic regression analyses. RESULTS: Final data sets included responses from 553 horse owners and 263 veterinarians. Pain scores varied widely and differences in median scores from horse owners and veterinarians were small. Horse owners providing high pain ratings were more likely to have <10 horses (odds ratio [OR] = 2.0, 95% CI = 1.1-3.5) and to not have a college degree (OR = 1.5, 95% CI = 1.0-2.2). Those providing low pain ratings were less likely to own <10 horses (OR = 0.6, 95% confidence interval [CI] = 0.4-0.9). Veterinarians providing high pain ratings were more likely to be employed in a mixed animal practice (OR = 2.8, 95% CI = 1.3-5.9) and to lack board-certification in a veterinary specialty (OR = 2.1, 95% CI = 1.1-4.2). Veterinarians providing low pain ratings were more likely to be male (OR = 2.4, 95% CI = 1.3-4.2). MAIN LIMITATIONS: The respondent population may be biased because of the method of questionnaire distribution and associated sampling bias. Respondents were primarily from the United States. CONCLUSIONS: Assessments of the degree of pain horses are experiencing vary widely among horse owners and equine veterinarians.

Effect of season and geographic location in the United States on detection of potential enteric pathogens or toxin genes in horses ≥6-mo-old.

We investigated the effects of season and geographic location on detection of nucleic acids of potential enteric pathogens (PEPs) or their toxins (PEP-Ts) in feces of horses ≥6-mo-old in the United States. Results of 3,343 equine diarrhea PCR panels submitted to Idexx Laboratories for horses >6-mo-old were reviewed. Submission months were grouped into 4 seasons, and states were grouped into 4 geographic regions. Logistic regression was performed to assess effects of season and region on detection rates of PEPs and PEP-Ts. Agresti-Coull CIs were determined. Detection rate of Salmonella enterica was higher in the South in summer compared to all other regions, and was also higher in the South in fall compared to the Midwest and Northeast. The Neorickettsia risticii detection rate was lower during summer in the West and higher in fall in the Midwest. Detection of Cryptosporidium spp. was lower during spring, summer, and winter in the West. Differences were not identified for detection rates of Clostridioides difficile, Clostridium perfringens, Lawsonia intracellularis, Rhodococcus equi, equine rotavirus, and equine coronavirus. Overall, our data support seasonal and regional differences in detection rates of S. enterica, N. risticii, and Cryptosporidium spp. in horses ≥6-mo-old in the United States.

Microbial Variability of Commercial Equine Probiotics.

Probiotics are defined as live microorganisms that confer a health benefit to the host when administered in adequate amounts, therefore the presence of viable microorganisms is essential. Previous studies reported inconsistencies when comparing contents of probiotics marketed for use in animals with label claims. However, to the author's knowledge the variability of the same product between different lots has yet to be evaluated. The objective of this observational study was to evaluate the content and inter-lot variability of commercial equine probiotic products using culture dependent and independent techniques. Eleven probiotics marketed for use in horses were evaluated for microbial content using culture-dependent and independent techniques. The content was then compared to microorganisms listed and quantities on the label of the probiotic. Statistical analyses were performed using a Kruskal-Wallis test. None of the 11 probiotics met their label claim. Nine of the 11 did not have statistically significant inter-lot variability. Several products lacked microorganisms listed on the label based on both culture and polymerase chain reaction (PCR) analyses.

Rules of Engagement: Epithelial-Microbe Interactions and Inflammatory Bowel Disease.

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are complex, multifactorial disorders that lead to chronic and relapsing intestinal inflammation. The exact etiology remains unknown, however multiple factors including the environment, genetic, dietary, mucosal immunity, and altered microbiome structure and function play important roles in disease onset and progression. Supporting this notion that the gut microbiota plays a pivotal role in IBD pathogenesis, studies in gnotobiotic mice have shown that mouse models of intestinal inflammation require a microbial community to develop colitis. Additionally, antimicrobial therapy in some IBD patients will temporarily induce remission further demonstrating an association between gut microbes and intestinal inflammation. Finally, a dysfunctional intestinal epithelial barrier is also recognized as a key pathogenic factor in IBD. The intestinal epithelium serves as a barrier between the luminal environment and the mucosal immune system and guards against harmful molecules and microorganisms while being permeable to essential nutrients and solutes. Beneficial (i.e., mutualists) bacteria promote mucosal health by strengthening barrier integrity, increasing local defenses (mucin and IgA production) and inhibiting pro-inflammatory immune responses and apoptosis to promote mucosal homeostasis. In contrast, pathogenic bacteria and pathobionts suppress expression and localization of tight junction proteins, cause dysregulation of apoptosis/proliferation and increase pro-inflammatory signaling that directly damages the intestinal mucosa. This review article will focus on the role of intestinal epithelial cells (IECs) and the luminal environment acting as mediators of barrier function in IBD. We will also share some of our translational observations of interactions between IECs, immune cells, and environmental factors contributing to maintenance of mucosal homeostasis, as it relates to GI inflammation and IBD in different animal models.

Detection of pathogens in blood or feces of adult horses with enteric disease and association with outcome of colitis.

BACKGROUND: Rates of detecting ≥1 potential enteric pathogens (PEP) or toxins (PEP-T) in feces, blood, or both of horses ≥6 months of age with enteric disease and impact of multiple detections on outcome of horses with colitis has not been reported. OBJECTIVE: To determine detection rates of PEP/PEP-T in feces, blood, or both of horses with enteric disease and effect of detecting multiple agents on outcome of horses with colitis. ANIMALS: Thirty-seven hundred fifty-three fecal samples submitted to IDEXX Laboratories and 239 fecal and blood samples submitted to Michigan State University's Veterinary Diagnostic Laboratory (MSUVDL). METHODS: Retrospective evaluation of PEP/PEP-T testing results was performed to determine rates of detection of 1 or more PEP/PEP-T. Impact of detecting multiple agents on outcome was assessed in 239 horses hospitalized for colitis. RESULTS: One or more PEP/PEP-T was detected in 1175/3753 (31.3%) and 145/239 (60.7%) of samples submitted to IDEXX Laboratories and MSUVDL, respectively. In a hospitalized cohort, survival to discharge was lower (76%) in horses with 1 agent, compared to horses with either no (88%) or multiple (89%) agents. There was no difference (P = .78) in days of hospitalization between horses with 0 (1-17), 1 (1-33), and > 1 positive (1-20) result. There was no difference in cost of hospitalization (P = .25) between horses with 0 ($2357, $1110-15 553), 1 ($2742, $788-11 005), and >1 positive ($2560, $1091-10 895) result. CONCLUSIONS AND CLINICAL IMPORTANCE: Detection rates of PEP/PEP-T in horses with colitis vary with cohorts and tests performed. Detection of more than 1 PEP or PEP-T did not affect outcome.

Effect of an In Vitro Proximal Gastrointestinal Tract on Viability of Commercially Available Equine Probiotics.

Probiotics, by definition, are live micro-organisms and should remain viable when they reach the intended site of action which is typically the cecum and/or colon. In humans, probiotics often need enteric protection to survive transit through the proximal gastrointestinal (GI) tract. Typically, equine probiotics do not advertise enteric protection and to the author's knowledge the viability of equine probiotics after exposure to the proximal GI tract has not been evaluated. The objective of this study was to evaluate the effect of an in vitro simulation of the equine proximal GI tract on probiotic viability. We hypothesized that the simulated proximal GI tract would adversely effect microbial viability and that the adverse effects would be partially ameliorated by increasing the gastric pH to 4. A total of 11 products were evaluated of which six had at least one micro-organism that was adversely effected by exposure to the proximal GI tract and four of which had at least one micro-organism that was adversely affected when the gastric pH was increased to 4.0. Results from this study indicate that some micro-organisms in equine probiotics do not appear to be adversely affected by exposure to the equine proximal GI tract.

Evaluation of commercial probiotics for antimicrobial resistance genes.

The objective of this study was to determine if transferable antimicrobial resistance (AMR) genes are present in commercial animal probiotics. DNA was extracted from 50 probiotics, tested for the presence of bacterial DNA, and analyzed by polymerase chain reaction (PCR) for the presence of 8 transferrable AMR genes, including tetracycline, erythromycin, aminoglycoside, sulfonamide, and trimethoprim. Samples that were positive by PCR were confirmed by genome sequencing. Forty-seven (94%) products contained bacterial DNA. Of these, 97% contained at least 1 AMR gene, and 82% contained 2 or more. These results indicate that further evaluation of the risk for transmission of these AMR genes may be warranted.

Évaluation de probiotiques commerciaux pour des gènes de résistance aux antimicrobiens. L'objectif de la présente étude était de déterminer si des gènes transférables de résistance aux antimicrobiens (RAM) sont présents dans des probiotiques pour animaux du commerce. L'ADN a été extrait de 50 probiotiques, testé pour la présence d'ADN bactérien et analysé par réaction d'amplification en chaîne par la polymérase (PCR) pour la présence de huit gènes RAM transférables, incluant la tétracycline, l'érythromycine, les aminoglycosides, le sulfonamide et le triméthoprime. Les échantillons positifs par PCR ont été confirmés par séquençage du génome. Quarante-sept (94 %) produits contenaient de l'ADN bactérien. Parmi ceux-ci, 97 % contenaient au moins un gène RAM et 82 % en contenaient deux ou plus. Ces résultats indiquent qu'une évaluation plus approfondie du risque de transmission de ces gènes RAM peut être justifiée.(Traduit par Dr Serge Messier).

The Effect of Water Flavor on Voluntary Water Intake in Hospitalized Horses.

Hospitalized horses are at risk for colic due to several factors, all of which may reduce voluntary water intake (VWI) further contributing to the development of colic during hospitalization. Our objectives were to determine if using flavored water (sweet feed, peppermint, or apple-flavored electrolyte) increases VWI of hospitalized horses and to determine if horses consumed more flavored water versus plain water. We hypothesized that (1) in hospitalized horses the availability of flavored water results in more VWI than the availability of unflavored water and that (2) average intake of flavored water is larger for flavored versus unflavored within the experimental (flavored) group. Four groups of hospitalized horses (n = 10/group) were recruited. All horses were provided two buckets of water. Control horses were provided two buckets of plain water. The other three groups were provided one bucket of plain water and one bucket of flavored water (sweet feed, peppermint, or a commercial apple-flavored electrolyte). The total and the flavor-specific water consumed was recorded during a 72-hour period. There was weak evidence to suggest that the use of flavored water increases median total water intake of hospitalized horses by a factor of 1.76 [95% CI: 0.98 to 3.11] for sweet feed (P = .05) and 1.85 [95% CI: 1.03 to 3.33] for peppermint (P = .04). The results strongly supported that horses consumed more sweet feed-flavored water (27.0 mL/kg/day [95% CI: 14.6 to 39.3] more water) compared with plain water (P = .0001).

In Vitro Evaluation of the Effect of Storage at -20°C and Proximal Gastrointestinal Conditions on Viability of Equine Fecal Microbiota Transplant.

Fecal microbiota transplant (FMT), a technique used to restore normal intestinal microbial communities, has been successful in treating humans with Clostridioides difficile colitis. Subsequently, FMT is being used in veterinary patients with suspected intestinal dysbiosis. Unfortunately, little data are available regarding best practices for FMT in horses. The objective of this study was to evaluate the effects of storing manure prepared for equine FMT (MP-FMT) at -20°C for up to 4 weeks and passage through a simulated proximal gastrointestinal (GI) tract on the viability of MP-FMT. The results of this study indicate that storage at -20°C for greater than 1 week and exposure to conditions consistent with the proximal GI tract significantly decreased viability of the microbial population, with gram-negative enteric bacteria most significantly impacted. This preliminary evaluation indicates that further work is necessary to determine best practices to preserve the viability MP-FMT in horses.