Equine Endometritis Management and Immunological Responses

Equine endometritis represents a leading cause of subfertility in mares worldwide, encompassing acute, subclinical and persistent forms. Following breeding or uterine contamination, a coordinated innate immune response involving neutrophil recruitment, cytokine release and uterine clearance typically restores homeostasis within 48 hours. In susceptible mares, however, this inflammatory phase persists, leading to chronic tissue remodelling, fibrosis (endometrosis) and impaired conception rates. Management strategies range from targeted antimicrobials informed by sensitivity tests to advanced immunomodulatory therapies, including platelet-rich plasma and extracellular vesicle supplementation. Recent transcriptomic and proteomic approaches have elucidated key regulators—such as transforming growth factor-β and interleukins—in extracellular matrix turnover and fibroblast activation. These insights underpin novel interventions aimed at restoring uterine immunity while preserving fertility, emphasising a One Health perspective that addresses antimicrobial resistance and promotes sustainable breeding practices.

Research from Nature Portfolio

Transcriptomic analysis of mare endometrium at defined stages of endometrosis has revealed distinct gene expression profiles associated with inflammation, metabolism and fibrosis. In mild and moderate lesions, differentially expressed genes cluster around wound-healing and mitochondrial dysfunction pathways, with upstream regulators including TGF-β1, IL-4, IL-13 and IL-17. In vitro fibroblast assays demonstrated that these cytokines differentially modulate ADAMTS family members according to disease severity, offering precise targets to arrest fibrotic progression. A complementary study characterised the expression of matrix metallopeptidases (MMP-1, ‑2, ‑3, ‑9) and their inhibitors (TIMPs) in healthy versus fibrotic endometrium. Exposure of equine endometrial fibroblasts and epithelial cells to TGF-β1 upregulated MMP-1, ‑9, ‑13 and TIMP1 while downregulating MMP-3, highlighting the cytokine’s dual role in extracellular matrix remodelling and fibrosis regulation.

Equine Endometritis Management and Immunological Responses publication trend

The graph below shows the total number of articles in equine endometritis management and immunological responses across all publications each year (not limited to Nature Index journals).

Technical terms

Equine endometritis: Inflammation or infection of the mare’s uterine lining impairing fertility.

Persistent post-breeding induced endometritis (PPBIE): Prolonged uterine inflammation following breeding that fails to resolve within the normal clearance period.

Cytokines: Small proteins secreted by immune cells that regulate inflammation and tissue homeostasis.

Matrix metallopeptidases (MMPs): Enzymes that degrade extracellular matrix components during tissue remodelling and fibrosis.

Extracellular vesicles: Nano-sized, membrane-bound particles released by cells carrying bioactive molecules to modulate recipient cell function.

Platelet-rich plasma (PRP): Autologous plasma concentrate rich in platelets and growth factors used to promote tissue repair and modulate inflammation.

References

1. Amniotic Mesenchymal-Derived Extracellular Vesicles and Their Role in the Prevention of Persistent Post-Breeding Induced Endometritis. International Journal of Molecular Sciences (2023).
2. Clinical Aspects of Bacterial Distribution and Antibiotic Resistance in the Reproductive System of Equids. Antibiotics (2023).
3. Transcriptomic profiling of mare endometrium at different stages of endometrosis. Scientific Reports (2023).
4. Matrix metallopeptidase expression and modulation by transforming growth factor-β1 in equine endometrosis. Scientific Reports (2020).
5. Intrauterine Blood Plasma Platelet-Therapy Mitigates Persistent Breeding-Induced Endometritis, Reduces Uterine Infections, and Improves Embryo Recovery in Mares. Antibiotics (2021).