Osteoclast density is not increased in bone adjacent to radiolucencies (cysts) in juvenile equine medial femoral condyles

Rosalie Fortin-Trahan; Thibaut Lemirre; Elizabeth M. Santschi; Jennifer G Janes; Hélène Richard; Ursula Fogarty; Guy Beauchamp; Christiane A. Girard; Sheila Laverty

doi:10.1111/evj.13530

Osteoclast density is not increased in bone adjacent to radiolucencies (cysts) in juvenile equine medial femoral condyles

Rosalie Fortin-Trahan, Thibaut Lemirre, Elizabeth M. Santschi, Jennifer G Janes, Hélène Richard, Ursula Fogarty, Guy Beauchamp, Christiane A. Girard, Sheila Laverty

Veterinary Science

Research output: Contribution to journal › Article › peer-review

1 Scopus citations

Abstract

Background: There is a knowledge gap about how equine MFC subchondral radiolucencies (SR) arise and evolve. Osteoclasts are believed to have a role but have not been studied in situ. Objectives: To measure and compare osteoclast density and the percentage of chondroclasts in healthy and MFC SR specimens from juvenile Thoroughbreds. Study design: Cadaveric study. Methods: Medial femoral condyles (MFC) from a tissue bank of equine stifles were studied. Inclusion criteria were MFCs (≤8 months old) with a computed tomography SR lesion and histological focal failure of endochondral ossification (L group). Contralateral, lesion-free, MFCs were a control group (CC). Osteochondral slabs were cut through the lesion (L), a healthy site immediately caudal to the lesion, (internal control; IC) and the contralateral, site-matched controls (CC). Histological sections were immunostained with Cathepsin K for osteoclast counting. Osteoclasts in contact with the growth cartilage (chondroclasts) were also counted. The sections were segmented into regions of interest (ROI) at different depths in the subchondral bone: ROI₁ (0-1 mm), ROI₂ (1-3 mm) and ROI₃ (3-6 mm). Osteoclasts were counted and the bone area was measured in each ROI to calculate their density. Chondroclasts were counted in ROI₁. Results: Sections were studied from L and IC (n = 6) and CC sites (n = 5). Osteoclast density was significantly higher in ROI₁ when compared with ROI₃ in all groups. Although higher osteoclast density was measured in ROI₁ in the L group, no significant differences were detected when compared with control ROIs. The proportion of chondroclasts in ROI₁ was lower in the L sections when compared with controls but no significant differences were detected. Main limitations: Limited sample size. Conclusions: Osteoclasts are important actors in MFC subchondral bone development, digesting both growth cartilage (chondroclasts) and bone, but the pathophysiology of early MFC SRs cannot be explained solely by an increased osteoclast presence in the subchondral bone.

Original language	English
Pages (from-to)	989-998
Number of pages	10
Journal	Equine Veterinary Journal
Volume	54
Issue number	5
DOIs	https://doi.org/10.1111/evj.13530
State	Published - Sep 2022

Bibliographical note

Funding Information:
This study was supported by grants from Fonds en santé équine de la Faculté de médecine vétérinaire de l’Université de Montréal and Zoetis. Sheila Laverty's laboratory is currently funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and by the Quebec Cell, Tissue and Gene Therapy Network –ThéCell (a thematic network supported by the Fonds de recherche du Québec–Santé). We remain grateful for Dr John Mort's (RIP) gift of Cathepsin K antibodies to our laboratory. We would also like to extend our thanks to the technical staff at the University of Kentucky and Kansas State University for their assistance with sample collection.

Funding Information:
This study was supported by grants from Fonds en santé équine de la Faculté de médecine vétérinaire de l’Université de Montréal and Zoetis. Sheila Laverty's laboratory is currently funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and by the Quebec Cell, Tissue and Gene Therapy Network –ThéCell (a thematic network supported by the Fonds de recherche du Québec–Santé).

Publisher Copyright:
© 2021 EVJ Ltd.

Keywords

Cathepsin K
chondroclast
cyst
horse
medial femoral condyle
osteoclast
subchondral radiolucency

ASJC Scopus subject areas

Equine

Access to Document

10.1111/evj.13530

Cite this

@article{23226102f2594fe4b07e58677a49dc3c,

title = "Osteoclast density is not increased in bone adjacent to radiolucencies (cysts) in juvenile equine medial femoral condyles",

abstract = "Background: There is a knowledge gap about how equine MFC subchondral radiolucencies (SR) arise and evolve. Osteoclasts are believed to have a role but have not been studied in situ. Objectives: To measure and compare osteoclast density and the percentage of chondroclasts in healthy and MFC SR specimens from juvenile Thoroughbreds. Study design: Cadaveric study. Methods: Medial femoral condyles (MFC) from a tissue bank of equine stifles were studied. Inclusion criteria were MFCs (≤8 months old) with a computed tomography SR lesion and histological focal failure of endochondral ossification (L group). Contralateral, lesion-free, MFCs were a control group (CC). Osteochondral slabs were cut through the lesion (L), a healthy site immediately caudal to the lesion, (internal control; IC) and the contralateral, site-matched controls (CC). Histological sections were immunostained with Cathepsin K for osteoclast counting. Osteoclasts in contact with the growth cartilage (chondroclasts) were also counted. The sections were segmented into regions of interest (ROI) at different depths in the subchondral bone: ROI1 (0-1 mm), ROI2 (1-3 mm) and ROI3 (3-6 mm). Osteoclasts were counted and the bone area was measured in each ROI to calculate their density. Chondroclasts were counted in ROI1. Results: Sections were studied from L and IC (n = 6) and CC sites (n = 5). Osteoclast density was significantly higher in ROI1 when compared with ROI3 in all groups. Although higher osteoclast density was measured in ROI1 in the L group, no significant differences were detected when compared with control ROIs. The proportion of chondroclasts in ROI1 was lower in the L sections when compared with controls but no significant differences were detected. Main limitations: Limited sample size. Conclusions: Osteoclasts are important actors in MFC subchondral bone development, digesting both growth cartilage (chondroclasts) and bone, but the pathophysiology of early MFC SRs cannot be explained solely by an increased osteoclast presence in the subchondral bone.",

keywords = "Cathepsin K, chondroclast, cyst, horse, medial femoral condyle, osteoclast, subchondral radiolucency",

author = "Rosalie Fortin-Trahan and Thibaut Lemirre and Santschi, {Elizabeth M.} and Jennifer G Janes and H{\'e}l{\`e}ne Richard and Ursula Fogarty and Guy Beauchamp and Girard, {Christiane A.} and Sheila Laverty",

note = "Funding Information: This study was supported by grants from Fonds en sant{\'e} {\'e}quine de la Facult{\'e} de m{\'e}decine v{\'e}t{\'e}rinaire de l{\textquoteright}Universit{\'e} de Montr{\'e}al and Zoetis. Sheila Laverty's laboratory is currently funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and by the Quebec Cell, Tissue and Gene Therapy Network –Th{\'e}Cell (a thematic network supported by the Fonds de recherche du Qu{\'e}bec–Sant{\'e}). We remain grateful for Dr John Mort's (RIP) gift of Cathepsin K antibodies to our laboratory. We would also like to extend our thanks to the technical staff at the University of Kentucky and Kansas State University for their assistance with sample collection. Funding Information: This study was supported by grants from Fonds en sant{\'e} {\'e}quine de la Facult{\'e} de m{\'e}decine v{\'e}t{\'e}rinaire de l{\textquoteright}Universit{\'e} de Montr{\'e}al and Zoetis. Sheila Laverty's laboratory is currently funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and by the Quebec Cell, Tissue and Gene Therapy Network –Th{\'e}Cell (a thematic network supported by the Fonds de recherche du Qu{\'e}bec–Sant{\'e}). Publisher Copyright: {\textcopyright} 2021 EVJ Ltd.",

year = "2022",

month = sep,

doi = "10.1111/evj.13530",

language = "English",

volume = "54",

pages = "989--998",

number = "5",

}

TY - JOUR

T1 - Osteoclast density is not increased in bone adjacent to radiolucencies (cysts) in juvenile equine medial femoral condyles

AU - Fortin-Trahan, Rosalie

AU - Lemirre, Thibaut

AU - Santschi, Elizabeth M.

AU - Janes, Jennifer G

AU - Richard, Hélène

AU - Fogarty, Ursula

AU - Beauchamp, Guy

AU - Girard, Christiane A.

AU - Laverty, Sheila

N1 - Funding Information: This study was supported by grants from Fonds en santé équine de la Faculté de médecine vétérinaire de l’Université de Montréal and Zoetis. Sheila Laverty's laboratory is currently funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and by the Quebec Cell, Tissue and Gene Therapy Network –ThéCell (a thematic network supported by the Fonds de recherche du Québec–Santé). We remain grateful for Dr John Mort's (RIP) gift of Cathepsin K antibodies to our laboratory. We would also like to extend our thanks to the technical staff at the University of Kentucky and Kansas State University for their assistance with sample collection. Funding Information: This study was supported by grants from Fonds en santé équine de la Faculté de médecine vétérinaire de l’Université de Montréal and Zoetis. Sheila Laverty's laboratory is currently funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and by the Quebec Cell, Tissue and Gene Therapy Network –ThéCell (a thematic network supported by the Fonds de recherche du Québec–Santé). Publisher Copyright: © 2021 EVJ Ltd.

PY - 2022/9

Y1 - 2022/9

N2 - Background: There is a knowledge gap about how equine MFC subchondral radiolucencies (SR) arise and evolve. Osteoclasts are believed to have a role but have not been studied in situ. Objectives: To measure and compare osteoclast density and the percentage of chondroclasts in healthy and MFC SR specimens from juvenile Thoroughbreds. Study design: Cadaveric study. Methods: Medial femoral condyles (MFC) from a tissue bank of equine stifles were studied. Inclusion criteria were MFCs (≤8 months old) with a computed tomography SR lesion and histological focal failure of endochondral ossification (L group). Contralateral, lesion-free, MFCs were a control group (CC). Osteochondral slabs were cut through the lesion (L), a healthy site immediately caudal to the lesion, (internal control; IC) and the contralateral, site-matched controls (CC). Histological sections were immunostained with Cathepsin K for osteoclast counting. Osteoclasts in contact with the growth cartilage (chondroclasts) were also counted. The sections were segmented into regions of interest (ROI) at different depths in the subchondral bone: ROI1 (0-1 mm), ROI2 (1-3 mm) and ROI3 (3-6 mm). Osteoclasts were counted and the bone area was measured in each ROI to calculate their density. Chondroclasts were counted in ROI1. Results: Sections were studied from L and IC (n = 6) and CC sites (n = 5). Osteoclast density was significantly higher in ROI1 when compared with ROI3 in all groups. Although higher osteoclast density was measured in ROI1 in the L group, no significant differences were detected when compared with control ROIs. The proportion of chondroclasts in ROI1 was lower in the L sections when compared with controls but no significant differences were detected. Main limitations: Limited sample size. Conclusions: Osteoclasts are important actors in MFC subchondral bone development, digesting both growth cartilage (chondroclasts) and bone, but the pathophysiology of early MFC SRs cannot be explained solely by an increased osteoclast presence in the subchondral bone.

AB - Background: There is a knowledge gap about how equine MFC subchondral radiolucencies (SR) arise and evolve. Osteoclasts are believed to have a role but have not been studied in situ. Objectives: To measure and compare osteoclast density and the percentage of chondroclasts in healthy and MFC SR specimens from juvenile Thoroughbreds. Study design: Cadaveric study. Methods: Medial femoral condyles (MFC) from a tissue bank of equine stifles were studied. Inclusion criteria were MFCs (≤8 months old) with a computed tomography SR lesion and histological focal failure of endochondral ossification (L group). Contralateral, lesion-free, MFCs were a control group (CC). Osteochondral slabs were cut through the lesion (L), a healthy site immediately caudal to the lesion, (internal control; IC) and the contralateral, site-matched controls (CC). Histological sections were immunostained with Cathepsin K for osteoclast counting. Osteoclasts in contact with the growth cartilage (chondroclasts) were also counted. The sections were segmented into regions of interest (ROI) at different depths in the subchondral bone: ROI1 (0-1 mm), ROI2 (1-3 mm) and ROI3 (3-6 mm). Osteoclasts were counted and the bone area was measured in each ROI to calculate their density. Chondroclasts were counted in ROI1. Results: Sections were studied from L and IC (n = 6) and CC sites (n = 5). Osteoclast density was significantly higher in ROI1 when compared with ROI3 in all groups. Although higher osteoclast density was measured in ROI1 in the L group, no significant differences were detected when compared with control ROIs. The proportion of chondroclasts in ROI1 was lower in the L sections when compared with controls but no significant differences were detected. Main limitations: Limited sample size. Conclusions: Osteoclasts are important actors in MFC subchondral bone development, digesting both growth cartilage (chondroclasts) and bone, but the pathophysiology of early MFC SRs cannot be explained solely by an increased osteoclast presence in the subchondral bone.

KW - Cathepsin K

KW - chondroclast

KW - cyst

KW - horse

KW - medial femoral condyle

KW - osteoclast

KW - subchondral radiolucency

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Osteoclast density is not increased in bone adjacent to radiolucencies (cysts) in juvenile equine medial femoral condyles

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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