Abstract: Gastrointestinal (GI) disease is a major cause of morbidity and mortality in horses, with disruption of the intestinal epithelial barrier playing a central role in disease pathogenesis. A deeper understanding of the molecular and functional properties of the equine intestinal barrier is essential to improve diagnostics and therapeutics. While intestinal organoids have emerged as a promising tool for modeling GI physiology and disease, equine-specific data remain limited. Existing studies vary in methodology and often lack functional characterization, particularly across different intestinal regions. The objective of this study was to establish a protocol for culturing equine intestinal organoids from distinct GI segments and to evaluate their barrier-related properties in comparison to native tissue. Organoids were successfully generated from equine duodenum, jejunum, and right dorsal colon using commercially available organoid growth (OGM) and organoid differentiation (ODM) media. All organoids formed spherical or budding structures with a central lumen and displayed viability across passages. Organoids in both media exhibited functional barrier characteristics, including transepithelial electrical resistance (TEER) and mucus production. However, transcriptomic and proteomic analysis revealed that ODM-grown organoids more closely resembled their tissue of origin than OGM-grown counterparts. Similarity was greatest in pathways related to cell adhesion, tight junctions, and epithelial transport. Discrepancies between organoids and tissue were largely related to metabolic activity and nutrient absorptive functions. Importantly, organoids retained segment-specific expression patterns, including absorptive and secretory markers, and more so in colonic organoids compared to small intestinal organoids. This study provides a detailed morphologic, functional, and molecular characterization of equine intestinal organoids derived from three distinct GI segments. Our findings contribute to the body of evidence demonstrating the importance of media composition to epithelial differentiation and segment-specific physiology. It also lays the groundwork for future applications, including host–pathogen interaction studies, drug permeability assays, and investigation of mucosal repair and regeneration in a segment-specific manner. The online version contains supplementary material available at 10.1186/s12917-025-05222-9.
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Overview
This study developed and characterized organoids—miniature, simplified versions of organs—from different sections of the horse intestine, to better understand how these structures mimic the natural intestinal barrier and how culture conditions affect their properties.
Introduction and Background
Gastrointestinal (GI) diseases cause significant health issues and death in horses, largely due to damage or disruption of the intestinal epithelial barrier.
The intestinal epithelial barrier plays a crucial role in protecting the gut and maintaining overall intestinal function.
A detailed understanding of the equine intestinal barrier at molecular and functional levels is needed to improve diagnostic tools and treatments for GI diseases in horses.
Intestinal organoids—three-dimensional, stem cell-derived cultures that mimic intestinal tissue—are emerging as valuable tools to study GI physiology and pathology.
While organoids have been studied in various species, equine-specific intestinal organoids have limited research, and most existing studies lack comprehensive functional assessments and comparisons across different intestinal regions.
Study Objectives
To establish a reliable protocol for culturing equine intestinal organoids from three distinct gastrointestinal segments: duodenum, jejunum, and right dorsal colon.
To evaluate and compare the functional barrier properties (such as barrier integrity and mucus production) of these organoids against native equine tissue.
To assess the molecular similarity of organoids to their tissue of origin using transcriptomic and proteomic analyses under two different culture media conditions.
Methods
Organoids were derived from three intestinal segments—duodenum, jejunum (small intestine), and right dorsal colon (large intestine)—from horses.
Two types of culture media were used:
Organoid Growth Media (OGM) designed to support growth and expansion.
Organoid Differentiation Media (ODM) designed to promote maturation and differentiation.
Organoid formation and morphology were monitored, assessing structure such as spherical or budding shapes with central lumens.
Functional assays included:
Transepithelial Electrical Resistance (TEER) to assess barrier integrity.
Mucus production to evaluate secretory function.
Molecular characterization involved:
Transcriptomic (gene expression) profiling to compare organoids with parent tissue.
Proteomic (protein expression) analysis to examine how closely organoids resemble native tissue at the protein level.
Key Findings
Organoids successfully grew from all three intestinal segments and maintained viability over multiple passages.
Both OGM and ODM media supported the formation of organoids that exhibited key intestinal epithelial barrier functions:
Both absorptive and secretory markers characteristic of their tissue of origin remained detectable.
These segment-specific features were more strongly retained in colon-derived organoids compared to those from the small intestine.
Significance and Applications
This study provides a comprehensive description of the morphology, function, and molecular profile of equine intestinal organoids from multiple GI segments, enhancing basic understanding of equine gut models.
It highlights the critical impact of culture media composition on the differentiation status and physiological fidelity of organoids.
Such organoids can serve as valuable tools for future research:
Modeling host–pathogen interactions specific to different intestinal regions.
Conducting drug permeability and toxicology assays tailored to equine GI physiology.
Investigating mechanisms of mucosal repair and regeneration post-injury on a segment-specific basis.
The availability of detailed molecular and functional characterization sets a foundation for improving veterinary diagnostics and therapeutics targeting equine GI diseases.
Supplementary materials for this study are accessible online for further technical details and data.
Cite This Article
APA
Richardson LM, Gordon J, Davila C, Chamoun-Emanuelli AM, Zdyrski C, Whitfield-Cargile CM.
(2026).
Functional and molecular characterization of equine intestinal organoids across media conditions and intestinal segments.
BMC Vet Res, 22(1), 142.
https://doi.org/10.1186/s12917-025-05222-9
Department of Large Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, GA, USA. lauren.richardson@uga.edu.
Gordon, Julie
Department of Large Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, GA, USA.
Davila, Carlos
Department of Large Animal Clinical Sciences, Texas A&M University, College Station, TX, USA.
Chamoun-Emanuelli, Ana M
Department of Large Animal Clinical Sciences, Texas A&M University, College Station, TX, USA.
Zdyrski, Christopher
SMART Pharmacology, Precision One Health Initiative, University of Georgia, Athens, GA, USA.
Whitfield-Cargile, Canaan M
Department of Large Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, GA, USA.
Department of Large Animal Clinical Sciences, Texas A&M University, College Station, TX, USA.
Conflict of Interest Statement
Declarations. Ethics approval and consent to participate: This study was approved by the Texas A&M University Institutional Animal Care and Use Committee (IACUC 2021 − 0164). Consent for publication: Not applicable. Competing interests: CZ is the Director of Research and Product Development at 3D Health Solutions. No other authors have competing interests.
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