Pulmonary bleeding in racehorses: A gross, histologic, and ultrastructural comparison of exercise-induced pulmonary hemorrhage and exercise-associated fatal pulmonary hemorrhage.
Abstract: Exercise-induced pulmonary hemorrhage (EIPH) is a common condition of Thoroughbred racehorses that is usually responsible for reduced performance, while exercise-associated fatal pulmonary hemorrhage (EAFPH) is characterized by severe pulmonary bleeding of unknown pathogenesis resulting in sudden death during strenuous exercise. The aim of the study was to characterize and compare anamnestic data together with pulmonary gross, histologic, and ultrastructural findings in racehorses with EIPH (n = 10), EAFPH (n = 10), and control horses (n = 5). No differences in anamnesis were identified between the 3 groups. Grossly cranial lobe reddening and edema scores were significantly more prevalent and severe in the EAFPH group compared with the EIPH and control groups. Histologically, hemorrhage scores were higher in the EAFPH group, while hemosiderophages, iron encrustations of collagen and elastin fibers, and vascular remodeling scores were significantly higher in EIPH group compared with the EAFPH and control groups. In all groups, caudal lung locations exhibited a significantly higher score for vascular remodeling, hemosiderophage accumulation, iron encrustation, and type II pneumocyte hyperplasia when compared with cranial, dorsal, and ventral locations. Ultrastructural analysis of perivascular collagen showed fibrils with significantly larger diameters in the EAFPH group compared with the EIPH group but not compared with the control group. This study demonstrates that lungs of horses that experienced EAFPH show significantly less vascular remodeling and other long-term pulmonary abnormalities that characterize horses with EIPH.
Publication Date: 2022-08-16 PubMed ID: 35972142PubMed Central: PMC9530536DOI: 10.1177/03009858221117859Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article investigates differences in the severity, physical presentation and histological characteristics of exercise-induced pulmonary hemorrhage (EIPH) and exercise-associated fatal pulmonary hemorrhage (EAFPH), two conditions related to lung bleeding in racehorses. The study reveals that while both conditions present pulmonary bleeding, EAFPH has less long-term pulmonary abnormalities compared to EIPH.
Objective of Research
- The primary aim of the study was to provide a detailed characterization of EIPH and EAFPH. It set out to examine anamnestic data, gross and microscopic (histologic and ultrastructural) findings of the lungs of racehorses. These data were then compared across horses that had suffered from EIPH, EAFPH and a set of control horses.
Study Participants and Methodology
- The study included ten horses for each of the two conditions, EIPH and EAFPH, and a smaller control group of five horses.
- The pulmonary findings for each horse were categorized with a focus on gross, histologic, and ultrastructural observations.
Results of the Study
- The study found no significant differences in the horses’ histories (anamnesis) among the three groups.
- Grossly, more severe instances of cranial lobe reddening and edema were observed in horses with EAFPH when compared to EIPH and control groups horses.
- From a histologic perspective, higher hemorrhage scores were seen in horses with EAFPH, while horses with EIPH demonstrated higher scores for hemosiderophages, iron encrustations of collagen and elastin fibers, and vascular remodeling.
- Interestingly, regardless of the group, lung areas nearer the tail (caudal locations) showed greater vascular remodeling, accumulation of hemosiderophage, iron encrustation, and hyperplasia of type II pneumocytes, when compared with cranial, dorsal, and ventral locations.
- Ultrastructural analysis revealed larger fibril diameters in the collagen surrounding blood vessels (perivascular collagen) in the EAFPH group compared to the EIPH group, but this difference was not observed when compared to the control group.
Conclusions
- The research provided evidence that while both EIPH and EAFPH involve lung bleeding as a symptom, they present unique characteristics. Horses experiencing EAFPH demonstrated less vascular remodeling and fewer long-term pulmonary abnormalities than those with EIPH.
Cite This Article
APA
Rocchigiani G, Verin R, Uzal FA, Singer ER, Pregel P, Ressel L, Ricci E.
(2022).
Pulmonary bleeding in racehorses: A gross, histologic, and ultrastructural comparison of exercise-induced pulmonary hemorrhage and exercise-associated fatal pulmonary hemorrhage.
Vet Pathol, 59(6), 973-982.
https://doi.org/10.1177/03009858221117859 Publication
Researcher Affiliations
- University of Liverpool, Neston, UK.
- University of Padua, Padua, Italy.
- University of California, Davis, Davis, CA.
- E Singer Equine Orthopaedics and Surgery, Parkgate, UK.
- University of Turin, Torino, Italy.
- University of Liverpool, Neston, UK.
- University of Liverpool, Neston, UK.
MeSH Terms
- Animals
- Collagen
- Elastin
- Hemorrhage / pathology
- Hemorrhage / veterinary
- Horse Diseases / pathology
- Horses
- Iron
- Lung / pathology
- Lung Diseases / etiology
- Lung Diseases / pathology
- Lung Diseases / veterinary
- Physical Conditioning, Animal / adverse effects
- Vascular Remodeling
Conflict of Interest Statement
The author(s) declared no potential conflicts of interest with respect to the research,
authorship, and/or publication of this article.
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Citations
This article has been cited 3 times.- Sugiyama F, Takahashi Y, Nomura M, Ebisuda Y, Mukai K, Yoshida T. Risk Factors for Epistaxis in Thoroughbred Flat Races in Japan (2001-2020). Animals (Basel) 2023 Apr 14;13(8).
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