Pulmonary bleeding in racehorses: A gross, histologic, and ultrastructural comparison of exercise-induced pulmonary hemorrhage and exercise-associated fatal pulmonary hemorrhage



Rocchigiani, Guido ORCID: 0000-0002-3742-7636, Verin, Ranieri ORCID: 0000-0001-9366-5682, Uzal, Francisco A, Singer, Ellen R, Pregel, Paola, Ressel, Lorenzo ORCID: 0000-0002-6614-1223 and Ricci, Emanuele ORCID: 0000-0001-9751-0661
(2022) Pulmonary bleeding in racehorses: A gross, histologic, and ultrastructural comparison of exercise-induced pulmonary hemorrhage and exercise-associated fatal pulmonary hemorrhage. VETERINARY PATHOLOGY, 59 (6). pp. 973-982.

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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.

Item Type: Article
Uncontrolled Keywords: exercise-induced pulmonary hemorrhage, hemosiderin, horse, iron encrustation, lung, sudden death, vascular remodeling
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Institute of Infection, Veterinary and Ecological Sciences
Depositing User: Symplectic Admin
Date Deposited: 12 Sep 2022 13:32
Last Modified: 18 Jan 2023 20:45
DOI: 10.1177/03009858221117859
Open Access URL: https://journals.sagepub.com/doi/full/10.1177/0300...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3164380