Could salivary biomarkers help detect Equine Gastric Ulcer Syndrome (EGUS)

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 Equine Gastric Ulcer Syndrome (EGUS) is a common problem in horses, affecting many disciplines and management systems. Currently, the only reliable way to diagnose EGUS is by gastroscopy – passing a flexible camera into the stomach to look for ulcers.

EGUS is divided into:

• Equine Squamous Gastric Disease (ESGD): ulcers in the upper, squamous portion of the stomach.
• Equine Glandular Gastric Disease (EGGD): ulcers in the lower, glandular portion.

The two forms have different likely causes and may require different management approaches.

While gastroscopy is the gold standard, it has some downsides: it requires specialist equipment, sedation, and a 12–16 hour fast. This can be costly and stressful for both horse and owner.

 

Dr. Marta Matas-Quintanilla and her team investigated whether five biomarkers in saliva could help identify EGUS:

• IL1-F5 - an immune-related protein.
• PIP (prolactin-inducible protein) - linked to immune and inflammatory processes.
• CA VI (carbonic anhydrase VI) - involved in saliva pH regulation.
• Serotransferrin - a protein that transports iron in the blood.
• Albumin - a major blood protein that can appear in saliva during inflammation or injury. 

Saliva is easy to collect, requires no needles, causes minimal stress, and can be taken by someone with basic handling skills; all big advantages for screening horses in the field.

 

The researchers measured these markers in three groups of adult horses, using validated sandwich ELISA tests (high precision and accuracy):

• No EGUS:  22 horses (3 - 20 years old) with no signs of EGUS and a clean gastroscopy.
• EGUS Non-Clinical: 28 horses (3 -14 years old) with no obvious signs, but ulcers seen on gastroscopy. Of these, 6 had ESGD, 11 had EGGD, and 11 had both types.
• EGUS Clinical: 37 horses (3 -18 years old) with obvious EGUS signs (e.g., poor performance, girthiness, changes in appetite or behaviour) and ulcers confirmed by gastroscopy. Of these, 9 had ESGD, 8 had EGGD, and 11 had both. Nine suspected horses with no ulcers on gastroscopy were excluded. 

The research team found that:

• IL1-F5, CA VI, serotransferrin, and albumin were significantly higher in EGUS clinical horses compared to No EGUS horses.
• PIP levels didn’t differ much between No EGUS and EGUS clinical horses.
• EGUS non-clinical horses showed differences in PIP and albumin compared to No EGUS horses.

They report that these markers could moderately distinguish between healthy and ulcer-affected horses, with sensitivity >77% and specificity >65%. The results suggest that measuring certain biomarkers in saliva could one day become a practical screening tool for EGUS. This would be especially useful for:

• Selecting which horses to send for gastroscopy.
• Monitoring horses at risk over time.
• Reducing unnecessary invasive procedures.

 

While gastroscopy will remain the definitive diagnostic method for now, salivary biomarkers offer a promising step toward faster, cheaper, and non-invasive detection of this common condition.

 

For more details, see: 

 

Matas-Quintanilla, Marta, Lynsey Whitacre, Ignacio R. Ipharraguerre, Cándido Gutiérrez-Panizo, and Ana M. Gutiérrez. 2025.

Assessment of Salivary Biomarkers of Gastric Ulcer in Horses from a Clinical Perspective

Animals 15, no. 15: 2251. 

https://doi.org/10.3390/ani15152251