Background Low bone mass is an essential extra-articular feature of rheumatoid arthritis (RA). Patients with RA might present an increased risk of low bone mass as a result of systemic inflammation by alteration of the RANK/RANKL/osteoprotegerin and Wnt/ catenin pathways. In RA, serum galectin-3 correlated with C-reactive protein levels and was considered as biomarker of inflammation. However, recent studies showed abundant galectin-3 observed in the area of severe bone destruction may act as a negative regulator for the upregulated osteoclastogenesis. The role of Galectin-3 is unclear in the regulation of bone resorption in RA.
Objectives The objectives of our study were to evaluate bone mineral density (BMD) and the levels of Galactin-3 and Dkk-1 in RA patients and to study the relation between these parameters.
Methods Patients with active RA were checked with galactin-3, Dkk-1 and followed up with BMD assessment and inflammatory evaluation by ultrasonography (US). Serum galectin-3, Dkk-1 concentrations were assayed with ELISA assay. BMD was measured at hip neck by a Dual-energy X-ray absorptiometry (DXA) (Explorer; Hologic Inc., USA). Grey scale and Power doppler US were graded using a 4-grade semiquantitative scoring system, on a scale of 0–3 at wrist. Each wrist was scanned from lateral to medial aspects in longitudinal planes Radius-Lunate-capitate (volar and dorsal), dorsal Radius-scaphoid-trapezoid, and dorsal Ulna-triquetral. Demographic and clinical data, DAS-28, and erythrocyte sedimentation rate (ESR) were recorded for each patient. Correlations between variables and multilinear regression analysis were performed to check serum galectin-3 expression levels and BMD parameters.
Results (1) Six RA patients 50% were female, age was 57.3±4.4 years, disease duration was 6.9±3.8 years and disease activity DAS 28 was 6.33±0.31. (2) The galectin-3, Sonography inflammatory score and serum iPTH levels showed a significant negative association with BMD at the hip.(Table.1) (3) The multilinear regression analysis showed iPTH, Galactin3 and US score were found to explain 99% of the variance in BMD in hip neck.(4) However, the galectin-3 in multilinear regression analysis showed a positive association with BMD at the hip. (correlation coefficient=0.126, p value=0.014) (Table.2)
Conclusions Galectin-3 is a major determinant of femoral neck BMD in this partial regression model, after controlling iPTH and sonography inflammatory score, in our preliminary study.
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Disclosure of Interest None declared