Exploring the Role of Hormones and Cytokines in Osteoporosis Development

Abstract

The disease of osteoporosis is characterized by impaired bone structure and an increased risk of fractures. There is a significant impact of cytokines and hormones on bone homeostasis and the diagnosis of osteoporosis. As defined by the World Health Organization (WHO), osteoporosis is defined as having a bone mineral density (BMD) that is 2.5 standard deviations (SD) or more below the average for young and healthy women (T score < -2.5 SD). Cytokines and hormones, particularly in the remodeling of bone between osteoclasts and osteoblasts, control the differentiation and activation of bone cells through cytokine networks and signaling pathways like the nuclear factor kappa-B ligand (RANKL)/the receptor of RANKL (RANK)/osteoprotegerin (OPG) axis, while estrogen, parathyroid hormones, testosterone, and calcitonin influence bone density and play significant roles in the treatment of osteoporosis. This review aims to examine the roles of cytokines and hormones in the pathophysiology of osteoporosis, evaluating current diagnostic methods, and highlighting new technologies that could help for early detection and treatment of osteoporosis.

Keywords: cytokines; hormones; osteoporosis.

Figure 1

Schematic representation of healthy bone (A), the two main cell types involved in bone remodeling: osteoblasts and osteoclasts (B) and osteoporotic bone (C). A healthy bone is characterized by a well-defined, thick trabecular structure, sufficient mineralization, and minimal signs of fractures or degradation. The structure of osteoporotic bone is characterized by advanced bone loss and weakening, as well as significant reductions in density and thickness of trabecular bone, which results in the appearance of porous and fragile bone. This figure was created using https://app.biorender.com/, accessed on 18 June 2024.

Figure 2

Cells expressing cytokine receptors. This figure was created using https://app.biorender.com/, accessed on 18 June 2024.

Figure 3

The upregulation and downregulation of cytokines in different cells during osteoporosis. (TNF-α can exhibit both upregulation and downregulation.) This figure was created using https://app.biorender.com/, accessed on 18 June 2024.