THE OPG/SRANKL SYSTEM AND THE LOW BONE MINERAL DENSITY IN POSTMENOPAUSAL OSTEOPOROSIS

Background. sRANKL (soluble receptor activator of nuclear factor-kappa B ligand) and OPG (osteoprotegerin) represent a novel cytokine system with pleiotropic effects oil bone remodeling. Aim. The aim Of this Study was to assess the implications of serum levels of sRANKL, OPG and E-2 (estradiol) in the process of bone remodeling of postmenopausal women with osteoporosis. Methods. The study was performed oil 74 patients with postmenopausal osteoporosis, divided into two groups of patients according to the duration of estrogenic deprivation, compared with a control group (n=20 postmenopausal women without osteoporosis). The serum levels of the enunciated markers were measured by ELISA technique. Results. In the, group I (n=48, bellow 15 yrs of estrogenic deprivation) the serum levels of sRANKL were 67.63 +/- 3.55 pg/mL (p<0.002), those of OPG were 42.15 +/- 0.55 pg/mL (p<0.002) and the levels of E, were 28.32 +/- 1.78 pg/ml (p<0.004). In the group II (n=26, over 15 yrs of estrogenic deprivation) the serum levels of sRANKL were 49.26 +/- 2.85 pg/mL (p<0.003), those of OPG 27.78 +/- 1.04 pg/mL (p<0.003) and the serum levels of E-2 were 19.66 +/- 1.23 pg/mL (p<0.002). In the control group (n=20), the serum levels of sRANKL were 32.48 +/- 3.03 pg/mL, those of OPG 38.05 +/- 4.89 pg/mL and the serum levels of E-2 were 43.07 +/- 4.04 pg/mL. Conclusions. The serum levels of sRANKL are significantly higher in postmenopausal women with osteoporosis versus postmenopausal women without osteoporosis, attesting osteoclasts activation. The serum levels of OPG in postmenopausal women with osteoporosis were increased in group I, suggesting the osteoblastic activation and decreased in group II, probably secondary to the stimulation of osteoblastic apoptosis.