The Influence of Radiation on Bone and Bone Cells—Differential Effects on Osteoclasts and Osteoblasts

Abstract

The bone is a complex organ that is dependent on a tight regulation between bone formation by osteoblasts (OBs) and bone resorption by osteoclasts (OCs). These processes can be influenced by environmental factors such as ionizing radiation (IR). In cancer therapy, IR is applied in high doses, leading to detrimental effects on bone, whereas radiation therapy with low doses of IR is applied for chronic degenerative and inflammatory diseases, with a positive impact especially on bone homeostasis. Moreover, the effects of IR are of particular interest in space travel, as astronauts suffer from bone loss due to space radiation and microgravity. This review summarizes the current state of knowledge on the effects of IR on bone with a special focus on the influence on OCs and OBs, as these cells are essential in bone remodeling. In addition, the influence of IR on the bone microenvironment is discussed. In summary, the effects of IR on bone and bone remodeling cells strongly depend on the applied radiation dose, as differential results are provided from in vivo as well as in vitro studies with varying doses of IR. Furthermore, the isolated effects of IR on a single cell type are difficult to determine, as the bone cells and bone microenvironment are building a tightly regulated network, influencing on one another. Therefore, future research is necessary in order to elucidate the influence of different bone cells on the overall radiation-induced effects on bone.

Quantitative in vivo micro-computed tomography for monitoring disease activity and treatment response in a collagen-induced arthritis mouse model

“…Reports in the literature associating ionizing radiation with dose-dependent effects on both blood components and bone necessitate verification that the X-ray dose used in vivo does not impose such effects 16 , 17 . Here, effects of ionizing radiation are investigated using naïve animals.…”

Influence of X-rays and gamma-rays on the mechanical performance of human bone factoring out intraindividual bone structure and composition indices

“…Workflows such as μCT imaging prior to and after mechanical testing do not influence the mechanical behavior of the bone according to the three-point bending test results. However, as a secondary effects of radiation, cell death has been shown in multiple cases [ 15 , 40 ] and may affect bone cells in vivo with subsequent mechanical deterioration [ 41 , 42 ] by a changed metabolism.…”

Radiomic Modeling of Bone Density and Rib Fracture Risk After Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer

“…The effect of radiation to healthy bone has been documented as having the largest effect on bone that contains red (hematopoietic) marrow as opposed to yellow (fatty) marrow, 33 observing that doses over 40 Gy may permanently impair the ability of sites of former red marrow to return to a hematopoietic state. The pathogenesis of this alteration has been documented primarily from reduced osteoblast activity after radiation, 34 thus leading to an increase in the osteoclast to osteoblast ratio, resulting in greater bone resorption and turnover. Given that these changes are similar to what is seen in osteoporosis, 35 we hypothesized that a relationship between radiation therapy to the rib and bone density may predict a rib fracture.…”