Cytokine measurements in Brazilian postmenopausal osteoporosis patients reveal high levels of IL-8

Abstract

Aims: Osteoporosis is a common disease that affects mostly women and has been associated with the immune system. The aims of this study were to evaluate the serum levels of inflammatory cytokines in women with postmenopausal osteoporosis and to investigate their relationship with clinical and laboratory parameters. Methods: This study recruited patients with postmenopausal osteoporosis (osteoporosis group) and non-osteoporotic postmenopausal women (control group) matched for age. All patients and controls had their bone mineral density measured for the diagnosis of osteoporosis and answered a clinical questionnaire. Blood samples were collected for cytokine measurements. Cytokines IFN-γ, IL-1β, IL-6, IL-8, IL-9, IL-10, IL-17A, IL-22, IL-27, IL-29, IL-35, and TNF-α were measured by an enzyme-linked immunosorbent assay. Results: Twenty-nine out of the 52 (55.8%) postmenopausal osteoporosis patients showed high levels of IL-8, while no patients from the control group (n=21) showed IL-8 values above the detection limit (p<0.0001). Higher levels of IFN-γ and IL-35 were associated with the control group, with p values of 0.0053 and 0.0214, respectively. In the osteoporosis group, IFN-γ was correlated with longer duration of smoking (p=0.003), IFN-γ and IL-6 were correlated with higher age at menarche (p=0.0454 and p=0.0380), IL-22 was correlated with duration of menopause (p=0.0289) and IL-9 with calcium intake (p=0.019). The other cytokines showed no association or correlation with clinical parameters. Conclusions: IL-8 was elevated in the serum of patients with postmenopausal osteoporosis, perhaps because it may trigger osteoclast activation and bone wear in osteoporosis. Higher levels of IFN-γ, IL-6, IL-9, IL-22, IL-27, and IL-35 were also associated with the osteoporosis group patients and showed significant correlation with clinical parameters in postmenopausal osteoporosis.