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Emerzian SR, Wu T, Vaidya R, Tang SY, Abergel RJ, Keaveny TM. Relative Effects of Radiation-Induced Changes in Bone Mass, Structure, and Tissue Material on Vertebral Strength in a Rat Model. J Bone Miner Res 2023; 38:1032-1042. [PMID: 37191221 PMCID: PMC10524463 DOI: 10.1002/jbmr.4828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 04/06/2023] [Accepted: 05/07/2023] [Indexed: 05/17/2023]
Abstract
The observed increased risk of fracture after cancer radiation therapy is presumably due to a radiation-induced reduction in whole-bone strength. However, the mechanisms for impaired strength remain unclear, as the increased fracture risk is not fully explained by changes in bone mass. To provide insight, a small animal model was used to determine how much of this whole-bone weakening effect for the spine is attributable to changes in bone mass, structure, and material properties of the bone tissue and their relative effects. Further, because women have a greater risk of fracture after radiation therapy than men, we investigated if sex had a significant influence on bone's response to irradiation. Fractionated in vivo irradiation (10 × 3 Gy) or sham irradiation (0 Gy) was administered daily to the lumbar spine in twenty-seven 17-week-old Sprague-Dawley rats (n = 6-7/sex/group). Twelve weeks after final treatment, animals were euthanized, and lumbar vertebrae (L4 and L5 ) were isolated. Using a combination of biomechanical testing, micro-CT-based finite element analysis, and statistical regression analysis, we separated out the effect of mass, structural, and tissue material changes on vertebral strength. Compared with the sham group (mean ± SD strength = 420 ± 88 N), the mean strength of the irradiated group was lower by 28% (117 N/420 N, p < 0.0001). Overall, the response of treatment did not differ with sex. By combining results from both general linear regression and finite element analyses, we calculated that mean changes in bone mass, structure, and material properties of the bone tissue accounted for 56% (66 N/117 N), 20% (23 N/117 N), and 24% (28 N/117 N), respectively, of the overall change in strength. As such, these results provide insight into why an elevated clinical fracture risk for patients undergoing radiation therapy is not well explained by changes in bone mass alone. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Shannon R. Emerzian
- Department of Mechanical Engineering, University of
California, Berkeley, California, USA
| | - Tongge Wu
- Department of Mechanical Engineering, University of
California, Berkeley, California, USA
| | - Rachana Vaidya
- Department of Orthopaedic Surgery, Washington University,
St. Louis, Missouri, USA
| | - Simon Y. Tang
- Department of Orthopaedic Surgery, Washington University,
St. Louis, Missouri, USA
- Department of Biomedical Engineering, Washington
University, St. Louis, Missouri, USA
- Department of Material Science & Mechanical
Engineering, Washington University, St. Louis, Missouri, USA
| | - Rebecca J. Abergel
- Department of Nuclear Engineering, University of
California, Berkeley, California, USA
| | - Tony M. Keaveny
- Department of Mechanical Engineering, University of
California, Berkeley, California, USA
- Department of Bioengineering, University of California,
Berkeley, California, USA
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Shi J, Xu K, Keyvanloo A, Udayakumar TS, Ahmad A, Yang F, Yang Y. A Multimodality Image Guided Precision Radiation Research Platform: Integrating X-ray, Bioluminescence, and Fluorescence Tomography With Radiation Therapy. Int J Radiat Oncol Biol Phys 2020; 108:1063-1072. [PMID: 32585336 DOI: 10.1016/j.ijrobp.2020.06.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 05/25/2020] [Accepted: 06/14/2020] [Indexed: 01/17/2023]
Abstract
PURPOSE Small animal irradiation is crucial to the investigation of radiobiological mechanisms. The paradigm of clinical radiation therapy is trending toward high-precision, stereotactic treatment. However, translating this scheme to small animal irradiation is challenging owing to the lack of high-quality image guidance. To overcome this obstacle, we developed a multimodality image guided precision radiation platform. METHODS AND MATERIALS The platform consists of 4 modules: x-ray computed tomography (CT), bioluminescence tomography (BLT), fluorescence molecular tomography (FMT), and radiation therapy. CT provides animal anatomy and material density for radiation dose calculation, as well as body contour for BLT and FMT reconstruction. BLT and FMT provide tumor localization to guide radiation beams and molecular activity to evaluate treatment outcome. Furthermore, we developed a Monte Carlo-based treatment planning system (TPS) for 3-dimensional dose calculation, calibrated it using radiochromic films sandwiched in a water-equivalent phantom, and validated it using in vivo dosimeters surgically implanted into euthanized mice (n = 4). Finally, we performed image guided irradiation on mice bearing orthotopic breast and prostate tumors and confirmed radiation delivery using γH2AX histology. RESULTS The Monte Carlo-based TPS was successfully calibrated by benchmarking simulation dose against film measurement. For in vivo dosimetry measured in the euthanized mice, the average difference between the TPS calculated dose and measured dose was 3.86% ± 1.12%. Following the TPS-generated treatment plan, we successfully delivered 20 Gy dose to an animal bearing an orthotopic prostate tumor using 4 BLT-guided radiation beams and 5 Gy dose to an animal bearing an orthotopic breast tumor using a single FMT-guided radiation beam. γH2AX histology presented significantly more DNA damage in irradiated tumors and thus validated the dose delivery accuracy. CONCLUSIONS Combined with Monte Carlo TPS, this multimodality CT/BLT/FMT image guided small animal radiation platform can specifically localize tumors, accurately calculate dose distribution, precisely guide radiation delivery, and molecularly evaluate treatment response. It provides an advanced toolset for radiobiology and translational cancer research.
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Affiliation(s)
- Junwei Shi
- University of Miami School of Medicine, Miami, Florida
| | - Keying Xu
- University of Miami School of Medicine, Miami, Florida; University Hospitals Cleveland Medical Center, Cleveland, Ohio
| | | | | | - Anis Ahmad
- University of Miami School of Medicine, Miami, Florida
| | - Fei Yang
- University of Miami School of Medicine, Miami, Florida
| | - Yidong Yang
- University of Miami School of Medicine, Miami, Florida; Department of Radiation Oncology, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China; School of Physical Sciences, University of Science and Technology of China, Hefei, China.
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Farris MK, Helis CA, Hughes RT, LeCompte MC, Borg AM, Nieto K, Munley MT, Willey JS. Bench to Bedside: Animal Models of Radiation Induced Musculoskeletal Toxicity. Cancers (Basel) 2020; 12:cancers12020427. [PMID: 32059447 PMCID: PMC7073177 DOI: 10.3390/cancers12020427] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/04/2020] [Accepted: 02/05/2020] [Indexed: 12/29/2022] Open
Abstract
Ionizing radiation is a critical aspect of current cancer therapy. While classically mature bone was thought to be relatively radio-resistant, more recent data have shown this to not be the case. Radiation therapy (RT)-induced bone loss leading to fracture is a source of substantial morbidity. The mechanisms of RT likely involve multiple pathways, including changes in angiogenesis and bone vasculature, osteoblast damage/suppression, and increased osteoclast activity. The majority of bone loss appears to occur rapidly after exposure to ionizing RT, with significant changes in cortical thickness being detectable on computed tomography (CT) within three to four months. Additionally, there is a dose–response relationship. Cortical thinning is especially notable in areas of bone that receive >40 gray (Gy). Methods to mitigate toxicity due to RT-induced bone loss is an area of active investigation. There is an accruing clinical trial investigating the use of risderonate, a bisphosphonate, to prevent rib bone loss in patients undergoing lung stereotactic body radiation therapy (SBRT). Additionally, several other promising therapeutic/preventative approaches are being explored in preclinical studies, including parathyroid hormone (PTH), amifostine, and mechanical loading of irradiated bones.
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Pendleton MM, Emerzian SR, Liu J, Tang SY, O'Connell GD, Alwood JS, Keaveny TM. Effects of ex vivo ionizing radiation on collagen structure and whole-bone mechanical properties of mouse vertebrae. Bone 2019; 128:115043. [PMID: 31445224 PMCID: PMC6813909 DOI: 10.1016/j.bone.2019.115043] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/14/2019] [Accepted: 08/21/2019] [Indexed: 12/26/2022]
Abstract
Bone can become brittle when exposed to ionizing radiation across a wide range of clinically relevant doses that span from radiotherapy (accumulative 50 Gy) to sterilization (~35,000 Gy). While irradiation-induced embrittlement has been attributed to changes in the collagen molecular structure, the relative role of collagen fragmentation versus non-enzymatic collagen crosslinking remains unclear. To better understand the effects of radiation on the bone material without cellular activity, we conducted an ex vivo x-ray radiation experiment on excised mouse lumbar vertebrae. Spinal tissue from twenty-week old, female, C57BL/6J mice were randomly assigned to a single x-ray radiation dose of either 0 (control), 50, 1000, 17,000, or 35,000 Gy. Measurements were made for collagen fragmentation, non-enzymatic collagen crosslinking, and both monotonic and cyclic-loading compressive mechanical properties. We found that the group differences for mechanical properties were more consistent with those for collagen fragmentation than for non-enzymatic collagen crosslinking. Monotonic strength at 17,000 and 35,000 Gy was lower than that of the control by 50% and 73% respectively, (p < 0.001) but at 50 and 1000 Gy was not different than the control. Consistent with those trends, collagen fragmentation only occurred at 17,000 and 35,000 Gy. By contrast, non-enzymatic collagen crosslinking was greater than control for all radiation doses (p < 0.001). All results were consistent both for monotonic and cyclic loading conditions. We conclude that the reductions in bone compressive monotonic strength and fatigue life due to ex vivo ionizing radiation are more likely caused by fragmentation of the collagen backbone than any increases in non-enzymatic collagen crosslinks.
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Affiliation(s)
- Megan M Pendleton
- Department of Mechanical Engineering, University of California, Berkeley, CA, USA
| | - Shannon R Emerzian
- Department of Mechanical Engineering, University of California, Berkeley, CA, USA
| | - Jennifer Liu
- Department of Orthopaedic Surgery, Washington University, St. Louis, MO, USA
| | - Simon Y Tang
- Department of Orthopaedic Surgery, Washington University, St. Louis, MO, USA; Department of Biomedical Engineering, Washington University, St. Louis, MO, USA; Department of Material Science & Mechanical Engineering, Washington University, St. Louis, MO, USA
| | - Grace D O'Connell
- Department of Mechanical Engineering, University of California, Berkeley, CA, USA; Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA
| | - Joshua S Alwood
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, USA
| | - Tony M Keaveny
- Department of Mechanical Engineering, University of California, Berkeley, CA, USA; Department of Bioengineering, University of California, Berkeley, CA, USA.
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Zhang J, Qiu X, Xi K, Hu W, Pei H, Nie J, Wang Z, Ding J, Shang P, Li B, Zhou G. Therapeutic ionizing radiation induced bone loss: a review of in vivo and in vitro findings. Connect Tissue Res 2018; 59:509-522. [PMID: 29448860 DOI: 10.1080/03008207.2018.1439482] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Radiation therapy is one of the routine treatment modalities for cancer patients. Ionizing radiation (IR) can induce bone loss, and consequently increases the risk of fractures with delayed and nonunion of the bone in the cancer patients who receive radiotherapy. The orchestrated bone remodeling can be disrupted due to the affected behaviors of bone cells, including bone mesenchymal stem cells (BMSCs), osteoblasts and osteoclasts. BMSCs and osteoblasts are relatively radioresistant compared with osteoclasts and its progenitors. Owing to different radiosensitivities of bone cells, unbalanced bone remodeling caused by IR is closely associated with the dose absorbed. For doses less than 2 Gy, osteoclastogenesis and adipogenesis by BMSCs are enhanced, while there are limited effects on osteoblasts. High doses (>10 Gy) induce disrupted architecture of bone, which is usually related to decreased osteogenic potential. In this review, studies elucidating the biological effects of IR on bone cells (BMSCs, osteoblasts and osteoclasts) are summarized. Several potential preventions and therapies are also proposed.
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Affiliation(s)
- Jian Zhang
- a State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection , Soochow University , Suzhou , China.,b Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , Suzhou , China
| | - Xinyu Qiu
- a State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection , Soochow University , Suzhou , China.,b Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , Suzhou , China
| | - Kedi Xi
- a State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection , Soochow University , Suzhou , China.,b Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , Suzhou , China
| | - Wentao Hu
- a State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection , Soochow University , Suzhou , China.,b Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , Suzhou , China
| | - Hailong Pei
- a State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection , Soochow University , Suzhou , China.,b Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , Suzhou , China
| | - Jing Nie
- a State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection , Soochow University , Suzhou , China.,b Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , Suzhou , China
| | - Ziyang Wang
- a State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection , Soochow University , Suzhou , China.,b Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , Suzhou , China
| | - Jiahan Ding
- a State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection , Soochow University , Suzhou , China.,b Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , Suzhou , China
| | - Peng Shang
- a State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection , Soochow University , Suzhou , China.,b Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , Suzhou , China.,c Key Laboratory for Space Bioscience and Biotechnology, Institute of Special Environmental Biophysics, School of Life Sciences , Northwestern Polytechnical University , Xi'an , China.,d Research & Development Institute in Shenzhen , Northwestern Polytechnical University, Fictitious College Garden , Shenzhen , China
| | - Bingyan Li
- a State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection , Soochow University , Suzhou , China
| | - Guangming Zhou
- a State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection , Soochow University , Suzhou , China.,b Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions , Suzhou , China
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