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Home / Equine Research Bank / J Equine Sci / Histopathological characteristics of endometrosis in thoroug...
Journal of equine science2014; 25(2); 45-52; doi: 10.1294/jes.25.45

Histopathological characteristics of endometrosis in thoroughbred mares in Japan: results from 50 necropsy cases.

Abstract: Uteri from 50 necropsied nonpregnant Japanese Thoroughbred brood mares (1-30 years of age) were investigated to clarify the histopathological characteristics of endometrosis in Japanese Thoroughbred mares and the distribution pattern of endometrosis lesions in the uterus as a whole. Endometrosis was observed in all animals over 6 years of age and in all of the 21 mares aged over 12 years of age. The affected mares showed elastofibrosis of arteries, veins and lymphatic vessels in the uterine wall, atrophy of the uterine smooth muscle layers and hyperplasia of collagen fibers among the smooth muscle fascicles of the myometrium, in addition to pathomorphologic features of endometrosis such as stromal endometrial fibrosis accompanied by endometrial atrophy, periglandular fibrosis and reduction of uterine glands. The severity of the histopathological changes increased with advancing age. Lymphatic vessels with elastofibrosis showed marked lymph congestion, leading to lymphatic edema. With increasing age, the extent of the distribution of these lesions tended to expand from focal to diffuse involvement of the entire uterus. Based on these findings, we speculate that aging plays a role in the pathogenesis of endometrosis; circulatory disturbances due to intrauterine angiosis or angiopathy, particularly reduction of the arterial blood supply and disturbance of venous drainage, resulting in a reduction of lymphatic drainage (lymphatic edema), are closely related to the onset and progression of endometrial fibrosis and myometrial atrophy with fibroplasia may result in myometrial hypofunction during the peri-implantation or puerperal period.
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Publication Date: 2014-06-25 PubMed ID: 25013358PubMed Central: PMC4090358DOI: 10.1294/jes.25.45Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research study investigates the histopathological features of endometrosis in Japanese Thoroughbred mares. This condition was found in all examined animals over the age of 6, and its severity increased with age. The study suggests that age-related circulatory disturbances contribute significantly to the onset and advancement of endometrosis.

Research Context

  • The study focuses on examining the histopathological characteristics of endometrosis in nonpregnant Thoroughbred mares in Japan. Endometrosis, a disorder characterized by fibrotic changes in the endometrium (the inner lining of the uterus), is associated with suboptimal fertility in horses.
  • The evaluation was carried out using the uteri of 50 mares, aged from 1 to 30 years, which were necropsied (autopsied).

Main Findings

  • Endometrosis was observed in every animal aged over six years and all 21 mares more than 12 years old.
  • Pathological changes in affected mares included a series of alterations in the uterus. These included elastofibrosis of the arteries, veins, and lymphatic vessels, hyperplasia of collagen fibers in the myometrium (muscle layer of the uterus), stromal endometrial fibrosis along with endometrial atrophy, periglandular fibrosis, and reduction in uterine glands.
  • Lymphatic vessels affected by elastofibrosis showed significant lymph congestion, leading to lymphatic edema.
  • Severity of changes increased as mares got older. In elder mares, lesions expanded from focal to a more diffuse presence affecting the entire uterus.

Conclusions and Speculations

  • The research points to aging as a major role player in the onset of endometrosis.
  • Furthermore, circulatory disturbances are found to be intimately associated with the onset and progression of the condition. Particularly, reduction in arterial blood supply and disturbances of venous drainage, leading to constraints in lymphatic drainage (lymphatic edema) could be crucial.
  • The study suggests that these changes could lead to endometrial fibrosis and myometrial atrophy. This may ultimately result in myometrial hypofunction during the peri-implantation or puerperal period, possibly explaining reduced fertility observed in mares diagnosed with endometrosis.

Cite This Article

APA
Hanada M, Maeda Y, Oikawa MA. (2014). Histopathological characteristics of endometrosis in thoroughbred mares in Japan: results from 50 necropsy cases. J Equine Sci, 25(2), 45-52. https://doi.org/10.1294/jes.25.45

Publication

Journal of equine science
ISSN: 1340-3516
NlmUniqueID: 9503751
Country: Japan
Language: English
Volume: 25
Issue: 2
Pages: 45-52

Researcher Affiliations

Hanada, Michiko
  • Faculty of Animal Health Technology, Department of Animal Health Technology, Yamazaki Gakuen University, Tokyo 150-0046, Japan.
Maeda, Yousuke
  • Laboratory of Large Animal Medicine, School of Veterinary Medicine, Kitasato University, Aomori 034-8628, Japan ; Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Florida 32610, USA.
Oikawa, Masa-Aki
  • Misawa Air Base Veterinary Clinic, US Army Public Health Command-Japan, APO, AP96319, Japan ; Equine Research Institute, Japan Racing Association, Tochigi 320-0856, Japan.

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Citations

This article has been cited 13 times.
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