Salivary biglycan-neo-epitope-BGN262: A novel surrogate biomarker for equine osteoarthritic sub-chondral bone sclerosis and to monitor the effect of short-term training and surface arena

S Adepu; M Lord; Z Hugoh; S Nyström; L Mattsson-Hulten; K Abrahamsson-Aurell; C Lützelschwab; E Skiöldebrand

doi:10.1016/j.ocarto.2023.100354

Salivary biglycan-neo-epitope-BGN²⁶²: A novel surrogate biomarker for equine osteoarthritic sub-chondral bone sclerosis and to monitor the effect of short-term training and surface arena

Osteoarthr Cartil Open. 2023 Mar 15;5(2):100354. doi: 10.1016/j.ocarto.2023.100354. eCollection 2023 Jun.

Authors

S Adepu¹, M Lord², Z Hugoh², S Nyström³, L Mattsson-Hulten³, K Abrahamsson-Aurell⁴, C Lützelschwab¹, E Skiöldebrand¹

Affiliations

¹ Department of Pathology, Institute of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.
² Department of Physics, Chalmers University of Technology, Gothenburg, Sweden.
³ Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, Sahlgrenska University Hospital, Gothenburg University, Gothenburg, Sweden.
⁴ Hallands Djursjukhus Kungsbacka Hästklinik, Älvsåkers Byväg 20, 434 95 Kungsbacka, Sweden.

Abstract

Objective: We aimed to delineate a novel soluble Biglycan Neo-epitope-BGN262 in saliva from young reference and osteoarthritic horses in conjunction with the influence of short-term training exercise, riding surface hardness, circadian rhythm, and feeding on its soluble levels.

Design: A custom-made inhibition ELISA was used for the quantification of BGN262 in saliva. Cohort 1: A cross-sectional study comprising reference (N = 19) and OA horses (N = 9) with radiographically classified subchondral bone sclerosis. Receiver operating characteristic curve analysis was performed to evaluate the robustness of BGN262. Cohorts 2 (N = 5) & 3 (N = 7): Longitudinal studies of sampling during a short-term training exercise (sand-fibre) and a cross-over design of short-training exercise on 2 different riding arenas (sand and sand-fibre), respectively. Capillary western immunoassay was used to determine the BGN262 molecular size in a selection of saliva samples collected from cohort 1.

Results: Cohort 1: Salivary BGN262 levels were significantly higher in the OA group. The Receiver operating characteristic curve analysis showed an area under the curve of 0.8304 [0.6386 to 1.022], indicating a good separation from the reference group. Cohorts 2 & 3: Salivary BGN262 levels significantly changed during the exercise on sand and sand-fibre arena, with a trend towards higher levels for sand-fibre. The size of the BGN262 fragment determined by Capillary western assay was 18 kDa.

Conclusions: The data presented show saliva BGN262 levels as a novel biomarker in evaluating the influence of exercise, and interaction with riding arenas alongside assessing osteoarthritis severity.

Keywords: Biglycan neo-epitope; Osteoarthritis; Riding surface; Saliva; Training.