Administration of trimethoprim-sulphadimidine does not improve healing of glandular gastric ulceration in horses receiving omeprazole: a randomised, blinded, clinical study

The Impact of Two Recommended Withholding Periods for Omeprazole and the Use of a Nutraceutical Supplement on Recurrence of Equine Gastric Ulcer Syndrome in Thoroughbred Racehorses

The impact of recommended withholding periods (RWPs) for omeprazole on the recurrence of Equine Gastric Ulcer Syndrome (EGUS) is unknown. The study was designed to compare the effect of two RWPs on EGUS recurrence post-omeprazole treatment and to determine if a nutraceutical supplement would reduce EGUS recurrence when administrated during an RWP. The study was a blinded, randomized clinical trial. Part 1: Horses were allocated to an RWP0 or RWP2 and crossed over after 4-weeks. Horses received oral omeprazole once daily, except during the RWPs at the end of the treatment periods. Part 2: Horses received omeprazole for 21 days prior to an RWP2 during which they received a nutraceutical supplement. Gastroscopy was performed on Day 0 and pre- and post- RWP. Part 1: More horses were affected by Equine Squamous Gastric Disease (ESGD) after the '2-clear-days' RWP than the 'not on race-day' RWP (p = 0.012). The prevalence of ESGD post-RWP for '2-clear-days' did not differ from day 0 (p = 0.478). Part 2: The prevalence of ESGD post-RWP was lower than on Day 0 (p = 0.046). A difference in recurrence of ESGD was present between the two common RWPs. The implications of this on the welfare of Thoroughbred racehorses warrant further discussion.

Equine Gastric Ulcer Syndrome: An Update on Current Knowledge

Equine Gastric Ulcer Syndrome (EGUS) is a term that has been used since 1999, initially being used to describe all gastric mucosal disease in horses. Since this time, the identification of two distinct main disease entities of the equine gastric mucosa have been described under the umbrella of EGUS; these are Equine Squamous Gastric Disease (ESGD) and Equine Glandular Gastric Disease (EGGD). In 2015 the European College of Equine Internal Medicine (ECEIM) released a consensus statement defining these disease entities. This document highlighted the lack of evidence surrounding EGGD compared to ESGD, and identified knowledge gaps for further research to be directed. Subsequently, many studies on EGGD have been published, especially on pathophysiology, diagnosis, and treatment. This article updates current knowledge on both ESGD and EGGD as understanding has evolved since the last large-scale review.

Does lesion type or severity predict outcome of therapy for horses with equine glandular gastric disease? - A retrospective study

BACKGROUND

Equine glandular gastric disease (EGGD) is a common condition of the horse. Misoprostol is reported to be superior to oral omeprazole and sucralfate for treatment. Long-acting intramuscular injectable omeprazole (LAIOMEP) is a novel treatment shown to be effective in a small population.

OBJECTIVES

This study aimed to determine LAIOMEP efficacy compared to misoprostol and oral omeprazole and identify characteristics that predict treatment outcome.

METHODS

All horses that underwent gastroscopy between 2012 and 2019 were reviewed. Lesions were characterised by 4 blinded observers, all of whom are diplomates in equine internal medicine, using established descriptors from the ECEIM consensus statement and subjective severity. Treatment outcome was ranked as worsened, improved or healed. Consensus lesion type, lesion severity and treatment choice were compared to outcome and data screened using univariate analysis (chi-squared) to determine whether each predicted outcome. Lesion types where univariate analysis predicted a trend (p<0.2) were included in a multiple-regression analysis to identify predictors of outcome irrespective of treatment.

RESULTS

Only severity significantly predicted final outcome (p = 0.025) with severe lesions being more likely to improve. Treatment choice did not significantly predict outcome. Overall healing rate was 29% (24 horses), and 43% (44 horses) improved. Treatment healing rates were 23% (10), 12% (7) and 27% (7) for LAIOMEP, misoprostol and oral omeprazole, respectively, with improvement in 69% (14), 76% (21) and 61% (9). 64% of the latter group received sucralfate. Worsening occurred in 7% (6). Treatment length varied with a median of 4 weeks (range 4-20 weeks).

CONCLUSIONS

This study showed poorer therapy outcome compared to previous studies. The only initial lesion descriptor to predict outcome was severity and treatment choice did not affect outcome.

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.

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.

Therapeutics for Equine Gastric Ulcer Syndrome

Equine gastric ulcer syndrome (EGUS) is an umbrella term used to describe ulcers in the nonglandular squamous and glandular mucosa, terminal esophagus, and proximal duodenum. Gastric ulcers in the squamous and glandular regions occur more often than esophageal or duodenal ulcers and likely have a different pathogenesis. At present, omeprazole is accepted globally as the best pharmacologic therapy for both regions of the stomach; however, the addition of coating agents and synthetic prostaglandins could add to its effectiveness in treatment of EGUS. Dietary and environmental management are necessary for prevention of recurrence.