High Serum Fractalkine is Associated with Lower Trabecular Bone Score in Premenopausal Women with Graves' Disease.

Abstract

Chemokine CX3CL1 (fractalkine) may be an important factor linking thyroid status and bone remodeling, through tetrac, a derivative of thyroxine. This study explores the relationship between serum fractalkine levels and parameters of thyroid status and bone in premenopausal women with Graves' disease (GD) in comparison to healthy controls. This cross-sectional study included three premenopausal female groups: active GD; cured GD, and healthy age-, gender-, and BMI-matched controls. Measurement of serum fractalkine levels (Quantikine® ELISA), total amino-terminal peptide of procollagen type 1 (P1NP), CTx, thyroid hormones, BMD and trabecular bone score (TBS) were performed in all study subjects. Sixty women (21, 16, and 23 in active GD, cured GD, and healthy control groups, respectively) were included. Serum fractalkine levels were higher (p<0.05) in active and cured GD subjects compared to healthy controls (mean 0.7±0.14; 0.93±0.15, and 0.48±0.13 ng/ml, respectively). Lumbar spine BMD was lowest in the cured GD group in comparison to active GD and control group subjects (0.926±0.03; 1.016±0.03; 1.051±0.03 g/cm2; p<0.05, respectively). TBS was lower (p<0.05) in both GD groups than controls being lowest in those with active GD (1.395±0.02; 1.402±0.02, 1.469±0.02, respectively). Serum fractalkine concentration was positively correlated with fT4, and negatively correlated with TBS values. GD in pre-menopausal females is associated with increased serum fractalkine concentration and decreased TBS. Fractalkine may be a currently unappreciated link between hyperthyroidism and bone; further research into this possibility is needed.