Inflammatory bowel disease (IBD) in horses: a retrospective study exploring the value of different diagnostic approaches

Approach to Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) in the horse encompasses a group of infiltrative gastrointestinal disorders resulting in malabsorption, maldigestion, weight loss, colic, and sometimes diarrhea. The type of IBD can be classified as granulomatous, lymphocytic-plasmacytic, or eosinophilic enterocolitis. The diagnosis of IBD in equids is based on consistent clinical signs and clinicopathologic findings in conjunction with confirmatory histopathology from a gastrointestinal biopsy. Treatment usually consists of a combination of immunosuppressive medications, anthelmintics, and dietary modifications. The prognosis of IBD in horses is variable and dependent on the horse's response to treatment; however, horses can show improvement or resolution of clinical signs.

Findings and Prognosis in 149 Horses with Histological Changes Compatible with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic disease characterized by different cell infiltrates in the intestine. The aims of this study were to report the clinical and clinicopathological findings in horses with histological changes compatible with IBD in the duodenum. Further, the clinical progression of IBD and survival were investigated. Patient records were reviewed for horses in which histological evidence of IBD was found in duodenal biopsies collected during endoscopy. The histological changes were classified as mild, moderate or severe and the predominant infiltrating cell type was recorded. Clinical improvement was assessed by the owner via a questionnaire at 6 weeks after biopsy, along with survival after one year. In total, 149 horses were included, and the most common clinical signs were weight loss, reduced performance and pain during abdominal palpation. Most horses showed partial malabsorption during an oral glucose absorption test, and the horses with severe IBD had lower serum protein concentrations. Lymphoplasmacytic enteritis was the most common type of IBD (78.5% of cases), while in six horses neutrophilic infiltration of the duodenum was present. Overall, 71% of the cases had improved clinically after six weeks, mostly following treatment with corticosteroids. The results of a second biopsy were a poor predictor of improvement, and the horses that improved after 6 weeks were more likely to be alive after one year.

Recurrent Colic: Diagnosis, Management, and Expectations

Most recurrent episodes of non-specific colic are self-limiting, and the results of clinical examinations are unremarkable. Differentiating these cases from serious diseases can be difficult, but repeated evaluations are warranted. Horses presenting with very frequent bouts of colic are more likely to have serious diseases and a higher mortality rate compared to horses presenting with less frequent bouts of transient colic. Horses with recurrent bouts of prolonged colic are more likely to have motility issues or partial intestinal obstruction. Non-gastrointestinal diseases can also cause recurrent bouts of pain ("false colic"). Adhesions are common causes of colic following abdominal surgery.

Retrospective Evaluation of the Most Frequently Observed Histological Changes in Duodenal and Rectal Mucosal Biopsies in Horses with Recurrent Colic

Colic, a condition affecting the gastrointestinal tract of horses, manifests as severe pain and may be a life-threatening condition. It is possible to distinguish between an acute, disposable process, as well as recurrent colic symptoms (abdominal pain) caused by an ongoing chronic inflammatory process. This paper presents a retrospective analysis of the histopathological findings of duodenal and rectal samples taken from horses with recurrent colic, with the aim to determine the frequency and extent of inflammation. The samples, i.e., duodenal biopsy (60 samples) and rectal biopsy (17 samples), were taken from 77 horses showing recurrent colic symptoms. Histopathological examination included staining with hematoxylin and eosin. The examination included evaluation of the superficial epithelium, mucosal lamina propria, and submucosa. All samples from the duodenum and rectum showed the presence of leukocyte infiltration in the mucosal lamina propria. The most frequently observed cellular infiltration was a moderate infiltration consisting of lymphocytes and plasma cells in duodenum and mixed populations of plasma cells, lymphocytes, and eosinophilia in the rectum. Mott cells were also noted among the inflammatory infiltrates. More than one-fourth of the horses were found to have shortened intestinal villi. The results presented here showed the involvement of inflammation in the course of recurrent colic, which can be both its cause (by impairing motility and absorption) and its effect (as a result of obstruction or ischemia).

Gastrointestinal biopsy in the horse: overview of collection, interpretation, and applications

Evaluation of gastrointestinal (GI) biopsies is a multistep process that includes reviewing an appropriate history, determining sample quality, and evaluating histologic sections. Selected diagnostic parameters that, in combination with intestinal histopathology, can be useful to localize disease to the intestinal tract in the horse include hypoproteinemia and hypoalbuminemia, ultrasound evidence of increased thickness of the small intestinal wall, and alterations in glucose or D-xylose absorption tests. Biopsies may be acquired either endoscopically, or via laparoscopy or standing flank incisional approaches. GI sections should be evaluated using a systematic approach that includes both architectural changes and inflammatory cell infiltrates. Although strategies have been developed for assessment of GI biopsies from the dog and cat, a standardized approach to interpretation of the equine GI biopsy has yet to be developed. GI biopsies pose several challenges to the pathologist, especially for endoscopic biopsies in which the quality of the specimen and its orientation may vary greatly. Architectural changes are arguably the most critical changes to evaluate. In a horse with chronic GI inflammation, such as occurs in idiopathic inflammatory bowel disease (IBD), the cell types encountered frequently are macrophages, eosinophils, lymphocytes, and plasma cells. Increased numbers of these cell types are categorized loosely as mild, moderate, and severe. Specific forms of idiopathic IBD have been further classified by this infiltrate as granulomatous enteritis, eosinophilic enteritis, and lymphoplasmacytic enteritis; there is limited information on microscopic changes with each. Unfortunately, microscopic GI lesions are usually nonspecific, and determination of etiology requires further investigation.

Comparison of two glucose-monitoring systems for use in horses

OBJECTIVE

To determine the accuracy of 2 interstitial glucose-monitoring systems (GMSs) for use in horses compared with a point-of-care (POC) glucometer and standard laboratory enzymatic chemistry method (CHEM).

ANIMALS

8 clinically normal adult horses.

PROCEDURES

One of each GMS device (Dexcom G6 and Freestyle Libre 14-day) was placed on each horse, and blood glucose concentration was measured via POC and CHEM at 33 time points and compared with simultaneous GMS readings. An oral glucose absorption test (OGAT) was performed on day 2, and glucose concentrations were measured and compared.

RESULTS

Glucose concentrations were significantly correlated with one another between all devices on days 1 to 5. Acceptable agreement was observed between Dexcom G6 and Freestyle Libre 14-day when compared with CHEM on days 1, 3, 4, and 5 with a combined mean bias of 10.45 mg/dL and 1.53 mg/dL, respectively. During dextrose-induced hyperglycemia on day 2, mean bias values for Dexcom G6 (10.49 mg/dL) and FreeStyle Libre 14-day (0.34 mg/dL) showed good agreement with CHEM.

CLINICAL RELEVANCE

Serial blood glucose measurements are used to diagnose or monitor a variety of conditions in equine medicine; advances in near-continuous interstitial glucose monitoring allow for minimally invasive glucose assessment, thereby reducing stress and discomfort to patients. Data from this study support the use of the Dexcom G6 and Freestyle Libre 14-day interstitial glucose-monitoring systems to estimate blood glucose concentrations in horses.

Inflammatory bowel disease characterized by multisystemic eosinophilic epitheliotropic disease (MEED) in a horse in Saskatchewan, Canada

A 3-year-old Quarter Horse gelding was evaluated for chronic weight loss, diarrhea, and pruritus. Physical examination revealed several ulcerative lesions on the skin and mucosal membranes. Diagnostic imaging findings were consistent with enteritis, typhlitis, and colitis. Multisystemic eosinophilic epitheliotropic disease (MEED) was diagnosed upon necropsy. This disease may be considered a form of equine inflammatory bowel disease complex which can be challenging to diagnose, requiring histological assessment, and in some cases, the use of immunohistochemical markers. Key clinical message: Multisystemic eosinophilic epitheliotropic disease is challenging to diagnose but should be considered in horses with chronic weight loss that fail to respond to conventional treatment for concurrent diarrhea and skin lesions.

Inflammation-Associated Microbiota Composition Across Domestic Animals

Domestic animals represent important resources for understanding shared mechanisms underlying complex natural diseases that arise due to both genetic and environmental factors. Intestinal inflammation, particularly inflammatory bowel disease (IBD), is a significant health challenge in humans and domestic animals. While the etiology of IBD is multifactorial, imbalance of symbiotic gut microbiota has been hypothesized to play a central role in disease pathophysiology. Advances in genomic sequencing and analytical pipelines have enabled researchers to decipher the composition of the intestinal microbiota during health and in the context of naturally occurring diseases. This review compiles microbiome genomic data across domestic species and highlights a common occurrence of gut microbiome dysbiosis during idiopathic intestinal inflammation in multiple species, including dogs, cats, horses, cows, and pigs. Current microbiome data obtained from animals with intestinal inflammation are mostly limited to taxonomical analyses in association with broad clinical phenotype. In general, a pathogen or pathosymbiont were not detected. Rather, functional potential of the altered microbiota has been suggested to be one of the key etiologic factors. Among the domestic species studied, canine analyses are currently the most advanced with incorporation of functional profiling of microbiota. Canine IBD parallels features of the disease in humans, thus canines represent a strong natural model for human IBD. While deeper analyses of metagenomic data, coupled with host molecular analyses are needed, comparative studies across domestic species can reveal shared microbial alterations and regulatory mechanisms that will improve our understanding of intestinal inflammation in both animals and humans.

Nutritional Considerations when Dealing with an Underweight Adult or Senior Horse

Weight loss occurs when the supply of energy is insufficient to meet the energy needs of an individual. The energy supply may be reduced by inadequate provision of feed, inadequate consumption, reduced digestion and absorption, or disruption in metabolic processing. Increased energy expenditure occurs with exercise and during cold temperatures, pregnancy, and lactation. Underlying clinical disease, particularly chronic inflammation, neoplasia, and protein-losing conditions, can cause weight loss or exacerbate existing weight loss. A methodical approach to weight-loss investigation and treatment is necessary, because of the often multifactorial nature of this condition.

Cannabis, One Health, and Veterinary Medicine: Cannabinoids' Role in Public Health, Food Safety, and Translational Medicine

Public health is connected to cannabis with regard to food, animal feed (feed), and pharmaceuticals. Therefore, the use of phytocannabinoids should be examined from a One Health perspective. Current knowledge on medical cannabis treatment (MCT) does not address sufficiently diseases which are of epidemiological and of zoonotic concern. The use of cannabinoids in veterinary medicine is illegal in most countries, mostly due to lack of evidence-based medicine. To answer the growing need of scientific evidence-based applicable medicine in both human and veterinary medicine, a new approach for the investigation of the therapeutic potential of cannabinoids must be adopted. A model that offers direct study of a specific disease in human and veterinary patients may facilitate development of novel therapies. Therefore, we urge the regulatory authorities-the ministries of health and agriculture (in Israel and worldwide)-to publish guidelines for veterinary use due to its importance to public health, as well as to promote One Health-related preclinical translational medicine studies for the general public health.

Current trends of antimicrobials used in food animals and aquaculture

Human population has been increasing rapidly, which ultimately increases human consumption, especially, animal protein requirements. Therefore, demands of animal protein consumption are increasing worldwide at an extraordinary rate. In order to meet the protein demand, intensive animal and aquaculture farming are considered. Like livestock farming (poultry, pigs, sheep, livestock, horses, rabbits, etc.), aquaculture farming (fish, crustaceans, mollusks, etc.) is also becoming the globe's emergent protein production sector. More than 580 aquaculture species are farmed worldwide. Current food animal and aquaculture farming are coupled with standard usage of antimicrobials. The antimicrobial drugs are major solutions for the management of contagious illnesses in food animals and aquaculture. In animal husbandry, antimicrobials are widely utilized for animal therapy, prophylaxis, or as growth promoters. Imprudent usage of these antimicrobials in food animals and aquaculture is a major contributing factor in the spread of antimicrobial resistance. The widespread use of veterinary medicines is considered to signify a frightening population health threat. It not only results in the disclosure and escalation of resistant microbes but also causes other individual, animal, and ecological deterioration. The contribution of resistant microbes from various sources seems to be the major base of resistance in the environment. However, strict policies and regulations for antimicrobial usage in food animals and aquaculture must be made and applied. It is important to prevent their negative effects in humans, food animals, aquaculture, and the environment.