Differences in selected blood parameters between brachycephalic and non-brachycephalic dogs

Sandra Kämpf; Simone Fenk; Ankie Van Cromvoirt; Nikolay Bogdanov; Sonja Hartnack; Martina Stirn; Regina Hofmann-Lehmann; Iris Margaret Reichler; Anna Bogdanova

doi:10.3389/fvets.2023.1166032

Differences in selected blood parameters between brachycephalic and non-brachycephalic dogs

Front Vet Sci. 2023 Aug 15:10:1166032. doi: 10.3389/fvets.2023.1166032. eCollection 2023.

Authors

Sandra Kämpf^{1

2

3}, Simone Fenk^{1

2}, Ankie Van Cromvoirt^{1

2}, Nikolay Bogdanov^{1

2}, Sonja Hartnack⁴, Martina Stirn⁵, Regina Hofmann-Lehmann^{2

5}, Iris Margaret Reichler^#³, Anna Bogdanova^#^{1

2}

Affiliations

¹ Red Blood Cell Research Group, Institute of Veterinary Physiology, Faculty of Vetsuisse, University of Zurich, Zürich, Switzerland.
² Center for Clinical Studies (ZKS), Vetsuisse Faculty, University of Zurich, Zürich, Switzerland.
³ Clinic of Reproductive Medicine, Vetsuisse Faculty, University of Zurich, Zürich, Switzerland.
⁴ Section of Epidemiology, Vetsuisse Faculty, University of Zurich, Zürich, Switzerland.
⁵ Clinical Laboratory, Department for Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zürich, Switzerland.

^# Contributed equally.

Abstract

Introduction: Cranial and upper-airway anatomy of short-nosed, flat-faced brachycephalic dogs predisposes them to brachycephalic obstructive airway syndrome (BOAS). Periodic apnoea increased inspiratory resistance, and an inability to thermoregulate effectively are characteristic of BOAS, but internationally accepted objective markers of BOAS severity are missing. The objective of this study was to compare the selected blood parameters between non-brachycephalic (NC) and brachycephalic (BC) dogs, exploring the possibility of developing a blood test for BOAS severity grading in the future.

Methods: We evaluated blood biochemistry, complete blood cell counts, red blood cell (RBC) indices, reticulocyte counts, a blood-born marker of intermittent hypoxia (glutathione, NO production), RBC hydration, deformability, and blood markers of metabolic changes and stress between BC (n = 18) and NC (meso- and dolichocephalic, n = 22) dogs.

Results: Reticulocyte counts and the abundance of middle-fluorescence immature reticulocytes were significantly (p < 0.05) higher in BC dogs compared to NC dogs. BC dogs had significantly more NO-derived NO $_{2}^{-}$ /NO $_{3}^{-}$ in plasma than NC dogs. RBCs of BC dogs were shedding significantly more membrane, as follows from the intensity of eosin maleimide staining, and had a significantly higher mean corpuscular hemoglobin concentration than NC dogs. Intracellular reduced glutathione content in RBCs of BC dogs was significantly lower, while plasma lactate was significantly higher in BC dogs compared to NC dogs. Plasma cholesterol and triglycerides were significantly lower, and cortisol was significantly higher in BC dogs compared to NC dogs. Eosinophil counts were significantly lower and the neutrophil-to-lymphocyte ratio was higher in BC dogs compared to NC dogs.

Discussion: Taken together, our findings suggest that the brachycephalic phenotype in dogs is associated with alterations at the level of blood cells and, systemically, with oxidation and metabolic changes. The parameters identified within this study should be further investigated for their potential as objective indicators for BOAS.

Keywords: blood markers; brachycephalic obstructive airway syndrome; brachycephaly; dog; hypoxia; red blood cells; stress.

Grants and funding

We acknowledge the Bundesamt für Lebensmittelsicherheit und Veterinärwesen for funding this study (ARAMIS-Nr. 2.20.01). AB, SF, and AV were supported by the SNF Sinergia funding (#CRSII5_180234).