Evaluation of the intestinal microbiota and correlation with functioning in patients suffering from knee osteoarthritis: a cross-sectional study

Purpose: The aim of this study was to evaluate the composition and metabolic activity of the gut microbiota (GM) in a cohort of patients suffering from knee osteoarthritis (OA) and its impact on their functional status. Methods: We recruited patients with a radiological diagnosis of mild-moderate knee OA (grade II or III according to the Kellgren and Lawrence classification). The primary outcome was the analysis of the intestinal microbiota (with stool sampling, DNA extraction and PCR and sequencing of the microbiota). The secondary outcomes were: Western Ontario and McMaster University Osteoarthritis index (WOMAC), Visual Analog Scale (VAS), Short Physical Performance Battery (SPPB), Timed Up and GO (TUG), Hand Grip Strength (HGS) test, and Berg Balance Scale (BBS). Results: This preliminary study included 17 patients aged 72.1±8.2 years. In these patients suffering from knee OA, in addition to alterations on the main physiatric scales administered (BBS: 40.727±11.22; HGS test: 18.73± 7.15; SPPB: 7.1± 3.13; WOMAC: 41.0±16.4; VAS 6/10), we were able to highlight an alteration in the composition of the microbiota, and in particular an increase in the physiological ratio, in favor of the Firmicutes vs. the Bacteroidetes phylum (v: 2.56 ± 1.78). Conclusions: These results, showing an alteration in the composition of the microbiota with an increase in the Firmicutes/Bacteroidetes ratio, point to a potential correlation between intestinal dysbiosis and arthrosis. There is therefore a need for more specific understanding of the role of the intestinal microbiota in the pathogenesis of OA, and of the pathogenetic mechanism of the gut-joint axis. KEY WORDS: Gut microbiota, osteoarthritis, Firmicutes, Bacteroidetes, gut-joint axis.