Endocrine Abstracts

The aim of the study: The paper analyzes the levels of soluble receptor activator of nuclear factor-κB ligand-(sRANKL), osteoprotegerin (OPG), bone alkaline phophatase (BAP), osteocalcin (BGP), estradiol, serum and bone levels of zinc [Zn⁽²⁺⁾], magnesium [Mg⁽²⁺⁾], calcium [Ca⁽²⁺⁾], phosphate [HPO4⁽²⁻⁾], and their correlation with bone mineral density (BMD).

Material and method: The study included 74 patients with postmenopausal osteoporosis, divided in two groups: group I (n=48, below 15 years of estrogenic deprivation) and group II (n=26, over 15 years of estrogenic deprivation). The control group comprised 20 postmenopausal women without osteoporosis.

The serum levels of the bone markers were measured by ELISA technique. Serum levels of the ions were measured by VitrosSlides quantitative technique and bone levels of the ions were assessed by means of bone flame atomic absorption spectrometry. Bone mineral density was measured using the DXA technique.

Results: The levels of sRANKL are significantly higher in postmenopausal osteoporosis versus controls, demonstrating the activation of osteoclastogenesis.

Serum OPG and BGP levels in postmenopausal osteoporosis were increased in group I, attesting the osteoblastic activation, and decreased in group II, secondary to the stimulation of osteoblastic apoptosis.

BAP is increased in postmenopausal osteoporosis, showing osteoblastic activation.

Estradiol levels are significantly lower in both groups, associated with low BMD.

Serum Ca⁽²⁺⁾ and HPO4⁽²⁻⁾ concentrations increase transitory, as a result of bone demineralization through hidroxiapatite microcrystal solubilization and mobilization of these ions in the circulation.

Conclusion: The decreased concentrations of ions in bone leads to localized bone demineralization, facilitating osteoporotic bone microfractures.