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Veterinary pathology2022; 59(6); 973-982; doi: 10.1177/03009858221117859

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

ISSN: 1544-2217
NlmUniqueID: 0312020
Country: United States
Language: English
Volume: 59
Issue: 6
Pages: 973-982

Researcher Affiliations

Rocchigiani, Guido
  • University of Liverpool, Neston, UK.
Verin, Ranieri
  • University of Padua, Padua, Italy.
Uzal, Francisco A
  • University of California, Davis, Davis, CA.
Singer, Ellen R
  • E Singer Equine Orthopaedics and Surgery, Parkgate, UK.
Pregel, Paola
  • University of Turin, Torino, Italy.
Ressel, Lorenzo
  • University of Liverpool, Neston, UK.
Ricci, Emanuele
  • 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.

References

This article includes 23 references
  1. Bal A, Bhalla A, Joshi K. Idiopathic pulmonary haemosiderosis with mineralizing pulmonary elastosis: a case report.. J Med Case Rep 2008 Feb 27;2:65.
    pmc: PMC2291061pubmed: 18304327doi: 10.1186/1752-1947-2-65google scholar: lookup
  2. Birk DE, Trelstad RL. Extracellular compartments in tendon morphogenesis: collagen fibril, bundle, and macroaggregate formation.. J Cell Biol 1986 Jul;103(1):231-40.
    pmc: PMC2113791pubmed: 3722266doi: 10.1083/jcb.103.1.231google scholar: lookup
  3. Caswell JL, Williams KJ. Respiratory system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. 6th ed. New York, NY: Elsevier; 2015:490–491.
  4. Collins TJ. ImageJ for microscopy.. Biotechniques 2007 Jul;43(1 Suppl):25-30.
    pubmed: 17936939doi: 10.2144/000112517google scholar: lookup
  5. Cook WR, Williams RM, Kirkerhead CA. Upper airway-obstruction (partial asphyxia) as the possible cause of exercise—induced pulmonary hemorrhage in the horse—an hypothesis. J Equine Vet Sci 1988;8:11–26.
  6. Edwards YS. Stretch stimulation: its effects on alveolar type II cell function in the lung.. Comp Biochem Physiol A Mol Integr Physiol 2001 May;129(1):245-60.
    pubmed: 11369549doi: 10.1016/s1095-6433(01)00321-xgoogle scholar: lookup
  7. Gold JR, Knowles DP, Coffey T, Bayly WM. Exercise-induced pulmonary hemorrhage in barrel racing horses in the Pacific Northwest region of the United States.. J Vet Intern Med 2018 Mar;32(2):839-845.
    pmc: PMC5866954pubmed: 29460489doi: 10.1111/jvim.15066google scholar: lookup
  8. Gunson DE, Sweeney CR, Soma LR. Sudden death attributable to exercise-induced pulmonary hemorrhage in racehorses: nine cases (1981-1983).. J Am Vet Med Assoc 1988 Jul 1;193(1):102-6.
    pubmed: 3417520
  9. Hinchcliff KW, Couetil LL, Knight PK, Morley PS, Robinson NE, Sweeney CR, van Erck E. Exercise induced pulmonary hemorrhage in horses: American College of Veterinary Internal Medicine consensus statement.. J Vet Intern Med 2015 May-Jun;29(3):743-58.
    pmc: PMC4895427pubmed: 25996660doi: 10.1111/jvim.12593google scholar: lookup
  10. Lyle CH, Uzal FA, McGorum BC, Aida H, Blissitt KJ, Case JT, Charles JT, Gardner I, Horadagoda N, Kusano K, Lam K, Pack JD, Parkin TD, Slocombe RF, Stewart BD, Boden LA. Sudden death in racing Thoroughbred horses: an international multicentre study of post mortem findings.. Equine Vet J 2011 May;43(3):324-31.
  11. McKane SA, Canfield PJ, Rose RJ. Equine bronchoalveolar lavage cytology: survey of thoroughbred racehorses in training.. Aust Vet J 1993 Nov;70(11):401-4.
  12. O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK. Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. II. Gross lung pathology.. Equine Vet J 1987 Sep;19(5):389-93.
  13. O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK. Exercise-induced pulmonary haemorrhage in the horse: results of a detailed clinical, post mortem and imaging study. V. Microscopic observations.. Equine Vet J 1987 Sep;19(5):411-8.
  14. Oikawa M. Exercise-induced haemorrhagic lesions in the dorsocaudal extremities of the caudal lobes of the lungs of young thoroughbred horses.. J Comp Pathol 1999 Nov;121(4):339-47.
    pubmed: 10542123doi: 10.1053/jcpa.1999.0331google scholar: lookup
  15. Pascoe JR, Ferraro GL, Cannon JH, Arthur RM, Wheat JD. Exercise-induced pulmonary hemorrhage in racing thoroughbreds: a preliminary study.. Am J Vet Res 1981 May;42(5):703-7.
    pubmed: 7258791
  16. Sorushanova A, Delgado LM, Wu Z, Shologu N, Kshirsagar A, Raghunath R, Mullen AM, Bayon Y, Pandit A, Raghunath M, Zeugolis DI. The Collagen Suprafamily: From Biosynthesis to Advanced Biomaterial Development.. Adv Mater 2019 Jan;31(1):e1801651.
    pubmed: 30126066doi: 10.1002/adma.201801651google scholar: lookup
  17. Sullivan S, Hinchcliff K. Update on exercise-induced pulmonary hemorrhage.. Vet Clin North Am Equine Pract 2015 Apr;31(1):187-98.
    pubmed: 25770069doi: 10.1016/j.cveq.2014.11.011google scholar: lookup
  18. Szturmowicz M, Kacprzak A, Szołkowska M, Burakowska B, Szczepulska E, Kuś J. Pulmonary veno-occlusive disease: pathogenesis, risk factors, clinical features and diagnostic algorithm - state of the art.. Adv Respir Med 2018;86(3).
    pubmed: 29960280doi: 10.5603/arm.2018.0021google scholar: lookup
  19. Tarancón I, Armengou L, Melendez-Lazo A, Pastor J, Ríos J, Jose-Cunilleras E. Prevalence of exercise-induced pulmonary hemorrhage in competing endurance horses.. J Am Vet Med Assoc 2019 Sep 15;255(6):710-715.
    pubmed: 31478814doi: 10.2460/javma.255.6.710google scholar: lookup
  20. West JB, Mathieu-Costello O, Jones JH, Birks EK, Logemann RB, Pascoe JR, Tyler WS. Stress failure of pulmonary capillaries in racehorses with exercise-induced pulmonary hemorrhage.. J Appl Physiol (1985) 1993 Sep;75(3):1097-109.
    pubmed: 8226517doi: 10.1152/jappl.1993.75.3.1097google scholar: lookup
  21. Williams KJ, Derksen FJ, de Feijter-Rupp H, Pannirselvam RR, Steel CM, Robinson NE. Regional pulmonary veno-occlusion: a newly identified lesion of equine exercise-induced pulmonary hemorrhage.. Vet Pathol 2008 May;45(3):316-26.
    pubmed: 18487488doi: 10.1354/vp.45-3-316google scholar: lookup
  22. Williams KJ, Robinson NE, Defeijter-Rupp H, Millerick-May M, Stack A, Hauptman J, Derksen FJ. Distribution of venous remodeling in exercise-induced pulmonary hemorrhage of horses follows reported blood flow distribution in the equine lung.. J Appl Physiol (1985) 2013 Apr;114(7):869-78.
  23. Yang TS, Rivers OS, Baumgartner WA. Mineralizing Pulmonary Elastosis in a Cat.. J Comp Pathol 2021 Aug;187:11-16.
    pubmed: 34503649doi: 10.1016/j.jcpa.2021.06.007google scholar: lookup

Citations

This article has been cited 3 times.
  1. 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).
    doi: 10.3390/ani13081348pubmed: 37106911google scholar: lookup
  2. Kapusniak A, Nath L, Hebart M, Franklin S. Heritability of sudden cardiac death in Thoroughbred racehorses. Equine Vet J 2025 Mar;57(2):325-332.
    doi: 10.1111/evj.14130pubmed: 38984817google scholar: lookup
  3. Shawaf T. Jugular venous thrombosis as a risk factor for exercise-induced pulmonary hemorrhage in thoroughbred racehorses. Open Vet J 2024 May;14(5):1111-1116.
    doi: 10.5455/OVJ.2024.v14.i5.4pubmed: 38938431google scholar: lookup