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. 2022 Jan;36(1):285-291.
doi: 10.1111/jvim.16333. Epub 2021 Dec 8.

Airway remodeling in horses with mild and moderate asthma

Amandine Bessonnat  1 , Pierre Hélie  2 , Carolyn Grimes  2 , Jean-Pierre Lavoie  1
Affiliations

Airway remodeling in horses with mild and moderate asthma

Amandine Bessonnat et al. J Vet Intern Med. 2022 Jan.

Abstract

Background: There is a remodeling of the central airways in horses with severe asthma but whether a similar process occurs in horses with the mild or moderate asthma (MMA) is unknown.

Objectives: To evaluate lesions affecting the central airways of horses with MMA.

Animals: Twelve horses with MMA and 8 control horses.

Methods: Case-control retrospective study of horses classified as MMA affected or controls based on history and bronchoalveolar lavage fluid cytology. Endobronchial biopsies were analyzed using histomorphometry and a semiquantitative histologic scoring system.

Results: Histomorphometry identified epithelial hyperplasia (47 μm2 /μm [34-57 μm2 /μm]; P = .02), a thickened lamina propria (166 μm [73-336 μm]; P = .04), and smooth muscle fibrosis (42% [33%-78%]; P = .04) in horses with MMA when compared to controls horses (24 μm2 /μm [21-80 μm2 /μm]; 76 μm [36-176 μm]; and 33% [26%-52%], respectively). The semiquantitative score results indicated, in horses with MMA, the presence of epithelial hyperplasia (7 of the 12 horses with MMA and only 1 of the 8 control horses had a score of 1/1), and submucosal inflammatory leucocytes in the central airway (11 of the 12 horses with MMA and only 4 of the 8 control horses had a score ≥ 1/2).

Conclusions and clinical relevance: Tissue remodeling of the bronchial lamina propria, epithelium, and smooth muscle was present in horses with MMA.

Keywords: central airway; endobronchial biopsy; histomorphometry; semiquantitative histologic score.

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Conflict of interest statement

Authors declare no conflict of interest.

Figures

FIGURE 1
FIGURE 1
Bronchoalveolar lavage cytology differential counts. Neutrophils (A), mast cells (B), and eosinophils (C) in horses with MMA (n = 12) and control horses (n = 8). Horizontal lines represent the median. MMA, mild or moderate asthma
FIGURE 2
FIGURE 2
Distance between the basement membrane and the bronchial smooth muscle layer in MMA (n = 10) and control (n = 6) horses (A), correlation between the percentage of extracellular matrix in the biopsy (%) and distance between the basement membrane and the bronchial smooth muscle (μm) in horses with MMA (n = 10; black dots; B) and control horses (n = 6, white dots; C). Two horses from each group were excluded for this measurement because of the low quantity of smooth muscle in the biopsy. Horizontal lines represent the median. MMA, mild or moderate asthma
FIGURE 3
FIGURE 3
Smooth muscle fibrosis in horses with MMA (n = 11) and control horses (n = 7). One horse from each group was excluded for this measurement because of the small quantity of smooth muscle in the biopsy. Horizontal lines represent the median. MMA, mild or moderate asthma
FIGURE 4
FIGURE 4
Epithelial hyperplasia in horses with MMA (n = 12) and control horses (n = 8). Horizontal lines represent the median. MMA, mild or moderate asthma
FIGURE 5
FIGURE 5
Semiquantitative histologic score (/14; A), submucosal leucocyte infiltration score (/2; B), and modified semiquantitative histologic score (/3; C) in horses with MMA and control horses. Horizontal lines represent the median. MMA, mild or moderate asthma
See this image and copyright information in PMC

References

    1. Richard EA, Fortier GD, Denoix JM, et al. Influence of subclinical inflammatory airway disease on equine respiratory function evaluated by impulse oscillometry. Equine Vet J. 2009;41:384‐389. - PubMed
    1. Couetil LL, Rosenthal FS, DeNicola DB, et al. Clinical signs, evaluation of bronchoalveolar lavage fluid, and assessment of pulmonary function in horses with inflammatory respiratory disease. Am J Vet Res. 2001;62:538‐546. - PubMed
    1. Jeffcott LB, Rossdale PD, Freestone J, et al. An assessment of wastage in thoroughbred racing from conception to 4 years of age. Equine Vet J. 1982;14:185‐198. - PubMed
    1. Rossdale PD, Hopes R, Digby NJ, Offord K. Epidemiological study of wastage among racehorses 1982 and 1983. Vet Rec. 1985;116:66‐69. - PubMed
    1. Robinson NE, Hoffman A, Couetil L, et al. Inflammatory airway disease: Defining the syndrome. Conclusions of the Havemeyer Workshop. Equine Vet Educ. 2003;15:61‐63.