In addition to anti-tumor effects, ionizing radiation causes damage in normal tissues located in the radiation portals. Oral complications of radiotherapy in the head and neck region are the result of the deleterious effects of radiation on, e.g., salivary glands, oral mucosa, bone, dentition, masticatory musculature, and temporomandibular joints. The clinical consequences of radiotherapy include mucositis, hyposalivation, taste loss, osteoradionecrosis, radiation caries, and trismus. Mucositis and taste loss are reversible consequences that usually subside early post-irradiation, while hyposalivation is normally irreversible. Furthermore, the risk of developing radiation caries and osteoradionecrosis is a life-long threat. All these consequences form a heavy burden for the patients and have a tremendous impact on their quality of life during and after radiotherapy. In this review, the radiation-induced changes in healthy oral tissues and the resulting clinical consequences are discussed.
The inflammasome promotes inflammation-associated diseases, including cancer, and contributes to the radiation-induced tissue damage. However, the role of inflammasome in radiation-induced antitumor effects is unclear. We observed that tumors transplanted in Casp1−/− mice were resistant to radiation treatment compared with tumors in wild-type (WT) mice. To map out which molecule in the inflammasome pathway contributed to this resistant, we investigated the antitumor effect of radiation in several inflammasome-deficient mice. Tumors grown in either Aim2−/− or Nlrp3−/− mice remained sensitive to radiation, like WT mice, whereas Aim2−/−Nlrp3−/− mice showed radioresistance. Mechanistically, extracellular vesicles (EVs) and EV-free supernatant derived from irradiated tumors activated both Aim2 and Nlrp3 inflammasomes in macrophages, leading to the production of interleukin-1β (IL-1β). IL-1β treatment helped overcome the radioresistance of tumors growing in Casp1−/− and Aim2−/−Nlrp3−/− mice. IL-1 signaling in dendritic cells (DCs) promoted radiation-induced antitumor immunity by enhancing the cross-priming activity of DCs. Overall, we demonstrated that radiation-induced activation of the AIM2 and NLRP3 inflammasomes coordinate to induce some of the antitumor effects of radiation by triggering IL-1 signaling in DCs, leading to their activation and cross-priming.
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More than half of cancer patients need radiotherapy during the course of their treatment. Despite the beneficial aspects, the destructive effects of radiation beams on normal tissues lead to oxidative stress, inflammation, and cell injury. Kidneys are affected during radiotherapy of abdominal malignancies. Radiation nephropathy eventually leads to the release of factors triggering systemic inflammation. Currently, there is no proven prophylactic or therapeutic intervention for the management of radiation-induced nephropathy. This article reviews the biomarkers involved in the pathophysiology of radiation-induced nephropathy and its underlying molecular mechanisms. The efficacy of compounds with potential radio-protective properties on amelioration of inflammation and oxidative stress is also discussed. By outlining the approaches for preventing and treating this critical side effect, we evaluate the potential treatment of radiation-induced nephropathy. Available preclinical and clinical studies on these compounds are also scrutinized.
Modern vascular surgeons perform an ever-increasing number of complex endovascular procedures, largely based on patient preference, decreased length of stay, and improved outcome. With the upsurge of endovascular cases, concern has grown regarding the harmful effects of radiation exposure delivered to the patient and the operator. Surgeon education on the appropriate use of fluoroscopic operating factors coupled with appropriate training in radiation safety has been shown to decrease radiation dose. This review elucidates dose terminology and metrics, possible radiation-induced injuries, risk factors for deterministic injury, and radiation safety principles and techniques. Tables provide practical tips to lower patient and operator radiation dose during fluoroscopically guided intervention, and National Council on Radiation Protection & Measurements recommended dose limits for occupational exposure. Figures illustrate reference air kerma, radiation-induced skin injury, effects of image receptor and table position, and operator exposure.
This review contains 4 figures, 3 tables, and 53 references.
Radiation-induced heart disease is a major cause of morbidity and mortality among cancer survivors. It encompasses many clinical entities, including pericardial disease, coronary artery disease, valvular disease, cardiomyopathy, conduction system abnormalities, autonomic dysfunction, and peripheral vascular disease. As the cardiovascular effects of radiation manifest many years after treatment, long-term follow-up with regular screening is essential. This chapter reviews the epidemiology and pathogenesis of radiation-induced heart disease as well as existing consensus recommendations regarding surveillance and management.
We investigated the potential involvement of ceramide-enriched membrane domains in radiation-induced targeted and nontargeted effects using head and neck squamous cell carcinoma with opposite radiosensitivities. In radiosensitive SCC61 cells, the proportion of targeted effects was 34% and nontargeted effects killed 32% of cells. In contrast, only targeted effects (30%) are involved in the overall death of radioresistant SQ20B cells. We then demonstrated in SCC61 cells that nontargeted cell response was driven by the formation of the radiation-induced ceramide-enriched domain. By contrast, the existence of these platforms in SQ20B cells confers a permissive region for phosphatidylinositol-3-kinase (PI3K)/AKT activation. The disruption of lipid raft results in strong inhibition of PI3K/AKT signaling, leading to radiosensitization and apparition of nontargeted effects. These results suggest that ceramide-enriched platforms play a significant role in targeted and nontargeted effects during radiotherapy and that drugs modulating cholesterol levels may be a good alternative for improving radiotherapy effectiveness.
Ceramide-Enriched Membrane Domains Contribute to Targeted and Nontargeted Effects of Radiation through Modulation of PI3K/AKT Signaling in HNSCC Cells