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Osteoarthritis biomarkers in the cat

WZ14-011   Identification of osteoarthritis biomarkers in the cat. (Winn Funded Study), Final progress report
Principal Investigators:  Drs. Thierry Beths, Jennifer Carter, and Sebastien Bauquier; University of Melbourne, Australia

The investigators have finished enrollment and have 20 fully enrolled osteoarthritic cats and 13 non-osteoarthritic cats. Seven (7) enrolled in the study could not be used as per exclusion criteria. All the serum samples have now been analysed for the different cytokines and HMGB1. Thanks to technological advancement, they have managed to analyse an extra 4 osteoarthritis related cytokines for no extra cost. The raw data, the demographic data and a preliminary statistical analysis are presented in appendix 1, 2 and 3 respectively.

As far as the authors are aware, this is the first Australian study looking at osteoarthritis (OA) in cats. They can confirm from their results that Australian cats do also suffer from OA and that the cats do not seem to show any obvious signs of OA related pain or lameness as none of the study’s cats were described by their owners as being in pain, lame or “unwell”. Some owners mentioned that their cats were quieter and less active than in the past. Those results are consistent with studies from the UK and from the USA and confirmed that OA is an insidious disease difficult to detect in cats who seem to suffer in silence (no obvious signs, but for the decrease in activity, changes in behaviour).

Five main conclusions can be drawn from those preliminary results:

1) The current study confirmed that, as other European and American studies, elbows and hips are the most commonly affected joints with detectable OA lesions on x-ray (Godfrey, 2005, Clarke and Bennett, 2006, Clarke et al., 2005).

2) OA seems to be more common in the ageing cats (p< 0.05), but can be found in younger patients (2 years of age in the current study) (Hardie et al. 2002; Clarke et al., 2005; Lascelles et al, 2010; Slingerland 2011). The effect of weight is less clear as some studies mention an effect and others do not. In this case, they almost reach significance (p = 0.068). A few more cats might have shown a significant difference.

3) The current study will be the first to report the level of some inflammation related biomarkers in the blood of osteoarthritic cats, with only IL 1 Beta being significantly different while MCP1 and, to a lesser extent, IL 6 showing about 50% increase without being significant. (Please be aware that their statisticians have not yet looked at the data and that those results may still change).

4) The lack of difference in the other cytokines may be caused by: 1) lack of specificity to OA in the cat; 2) most of their OA positive cats were in a “non-active” stage of OA, hence comparable results to normal.

5) Building on the last statement, longitudinal studies looking at evolution of cytokine levels in plasma over time might be more appropriate than cross-sectional studies looking at one time point only (Mobasheri et al., 2017).

See also:
Addison EN, Clements DN. Repeatability of quantitative sensory testing in healthy cats in a clinical setting with comparison to cats with osteoarthritis. J Feline Med Surg. 2017 Feb 1:1098612X17690653. doi: 10.1177/1098612X17690653. [Epub ahead of print]