Development of radiation countermeasure agents for acute radiation syndromes

The risk of internal and external exposure to ionizing radiation(IR)has increased alongside the development and implementation of nuclear technology.Therefore,serious security issues have emerged globally,and there has been an increase in the number of studies focusing on radiological prevention and medical countermeasures.Radioprotective drugs are particularly important components of emergency medical preparedness strategies for the clinical management of IR-induced injuries.However,a few drugs have been approved to date to treat such injuries,and the related mechanisms are not entirely understood.Thus,the aim of the present review was to provide a brief overview of the World Health Organization's updated list of essential medicines for 2023 for the proper management of national stockpiles and the treatment of radiological emergencies.This review also discusses the types of radiation-induced health injuries and the related mechanisms,as well as the development of various radioprotective agents,including Chinese herbal medicines,for which significant survival benefits have been demonstrated in animal models of acute radiation syndrome.

Radiation dermatitis wet healing:a concept analysis

Objective:To explore the concept of radiation dermatitis wet healing through a literature review and provide references for future treatment of patients with radiation skin injury.Methods:Related ar ticles selected from China National Knowledge Infrastructure(CNKI),Wanfang Database,Pub Med,Web of Science,Medline,and EBSCO were analyzed with Rodger’s concept analysis.Results:We identified the application status of wet healing in domestic and foreign literature,defined explicit attributes of the procedure,and clarified concepts related to wet healing of radiation skin injury to provide a reference for the management of radiation dermatitis with wet healing.Conclusions:Treatment of radiation dermatitis with wet healing is a unique procedure.Analyzing this concept can contribute to its development in the future and can offer a theoretical basis for treatment of patients with radiation skin injury.

Biomarkers Associated with Radiation-Induced Lung Injury in Cancer Patients

Radiotherapy (RT) is a common and effective non-surgical treatment for thoracic solid tumors, and radiation-induced lung injury (RILI) is the most common side effect of radiotherapy. Even if RT is effective in the treatment of cancer patients, severe radiation pneumonitis (RP) or pulmonary fibrosis (PF) can reduce the quality of life of patients and may even lead to serious consequences of death. Therefore, how to overcome the problem of accurate prediction and early diagnosis of RT for pulmonary toxicity is very important. This review summarizes the related factors of RILI and the related biomarkers for early prediction of RILI.

Significance of endothelial dysfunction in the pathogenesis of early and delayed radiation enteropathy

This review summarizes the current state of knowledge regarding the role of endothelial dysfunction in the pathogenesis of early and delayed intestinal radiation toxicity and discusses various endothelial-oriented interventions aimed at reducing the risk of radiation enteropathy. Studies published in the biomedical literature during the past four decades and cited in PubMed, as well as clinical and laboratory data from our own research program are reviewed. The risk of injury to normal tissues limits the cancer cure rates that can be achieved with radiation therapy. During treatment of abdominal and pelvic tumors, the intestine is frequently a major close-limiting factor. Microvascular injury is a prominent feature of both early （inflammatory）, as well as delayed （fibroproliferative） radiation injuries in the intestine and in many other normal tissues. Evidence from our and other laboratories suggests that endothelial dysfunction, notably a deficiency of endothelial thrombomodulin, plays a key role in the pathogenesis of these radiation responses. Deficient levels of thrombomodulin cause loss of vascular thromboresistance, excessive activation of cellular thrombin receptors by thrombin, and insufficient activation of protein C, a plasma protein with anticoagulant, anti-inflammatory, and cytoprotective properties. These changes are presumed to be critically involved in many aspects of early intestinal radiation toxicity and may sustain the fibroproliferative processes that lead to delayed intestinal dysfunction, fibrosis, and clinical complications. In conclusion, injury of vascular endothelium is important in the pathogenesis of the intestinal radiation response. Endothelial-oriented interventions are appealing strategies to prevent or treat normal tissue toxicity associated with radiation treatment of cancer.

Practical approaches to effective management of intestinal radiation injury:Benefit of resectional surgery

AIM:To study the outcome of patients undergoing surgical resection of the bowel for sustained radiation-induced damage intractable to conservative management.METHODS:During a 7-year period we operated on 17 cases (5 male,12 female) admitted to our surgical department with intestinal radiation injury (IRI).They were originally treated for a pelvic malignancy by surgical resection followed by postoperative radiotherapy.During follow-up,they developed radiation enteritis requiring surgical treatment due to failure of conservative management.RESULTS:IRI was located in the terminal ileum in 12 patients,in the rectum in 2 patients,in the descending colon in 2 patients,and in the cecum in one patient.All patients had resection of the affected region(s).There were no postoperative deaths,while 3 cases presented with postoperative complications (17.7%).All patients remained free of symptoms without evidence of recurrence of IRI for a median follow-up period of 42 mo (range,6-96 mo).CONCLUSION:We report a favorable outcome without IRI recurrence of 17 patients treated by resection of the diseased bowel segment.

Rupture of carotid artery pseudoaneurysm in the modern era of definitive chemoradiation for head and neck cancer:Two case reports

BACKGROUND Carotid blowout syndrome(CBS)is a rupture of the carotid artery and is mainly caused by radiation and resection of head and neck cancers or direct tumor invasion of the carotid artery wall.It is a life-threatening clinical situation.There is no established and effective mode of management of CBS.Furthermore,there is no established preceding sign or symptom;therefore,preventive efforts are not clinically meaningful.CASE SUMMARY We described two cases of CBS that occurred in patients with head and neck cancer after definitive chemoradiotherapy(CRT)using three-dimensional conformal intensity-modulated radiation therapy.Two men aged 61 and 56 years with locally advanced head and neck cancer were treated with definitive CRT.After completing CRT,both of them achieved complete remission.Subsequently,they had persistent severe pain in the oropharyngeal mucosal region and the irradiated neck despite the use of opioid analgesics and rehabilitation for relief of contracted skin.However,continuous follow-up imaging studies showed no evidence of cancer recurrence.Eleven to twelve months after completing CRT,the patients visited the emergency room complaining about massive oronasal bleeding.Angiograms showed rupture of carotid artery pseudoaneurysms on the irradiated side.Despite attempting to secure hemostasis with carotid arterial stent insertion and coil embolization,both patients died because of repeated bleeding from the pseudoaneurysms.CONCLUSION In patients with persistent pain in irradiated sites,clinicians should be suspicious of progressing or impending CBS,even in the three-dimensional conformal intensity-modulated radiation therapy era.

Hyperbaric oxygen therapy as a complementary treatment for radiation proctitis:Useless or useful?-A literature review

Radiotherapy(RT)is the backbone of multimodality treatment of more than half of cancer cases.Despite new modern RT techniques,late complications may occur such as radiation proctitis(RP).The natural history of RP is unpredictable.Minor symptoms may resolve spontaneously or require conservative treatment.On the other hand,for similar and uncomplicated clinical contexts,symptoms may persist and can even be refractory to the progressive increase in treatment measures.Over the last decades,an enormous therapeutic armamentarium has been considered in RP,including hyperbaric oxygen therapy(HBOT).Currently,the evidence regarding the impact of HBOT on RP and its benefits is conflicting.Additional prospective and randomised studies are necessary to validate HBOT’s effectiveness in the‘real world’clinical practice.This article reviewed the relevant literature on pathophysiology,clinical presentation,different classifications and discuss RP management including a proposal for a therapeutic algorithm with a focus on HBOT.

Neuroprotective agents effective against radiation damage of central nervous system

Ionizing radiation caused by medical treatments,nuclear events or even space flights can irreversibly damage structure and function of brain cells.That can result in serious brain damage,with memory and behavior disorders,or even fatal oncologic or neurodegenerative illnesses.Currently used treatments and drugs are mostly targeting biochemical processes of cell apoptosis,radiation toxicity,neuroinflammation,and conditions such as cognitive-behavioral disturbances or others that result from the radiation insult.With most drugs,the side effects and potential toxicity are also to be considered.Therefore,many agents have not been approved for clinical use yet.In this review,we focus on the latest and most effective agents that have been used in animal and also in the human research,and clinical treatments.They could have the potential therapeutical use in cases of radiation damage of central nervous system,and also in prevention considering their radioprotecting effect of nervous tissue.

DTI and pathological changes in a rabbit model of radiation injury to the spinal cord after ^(125)I radioactive seed implantation

Excessive radiation exposure may lead to edema of the spinal cord and deterioration of the nervous system. Magnetic resonance imaging can be used to judge and assess the extent of edema and to evaluate pathological changes and thus may be used for the evaluation of spinal cord injuries caused by radiation therapy. Radioactive ^125I seeds to irradiate 90% of the spinal cord tissue at doses of 40–100 Gy （D90） were implanted in rabbits at T10 to induce radiation injury, and we evaluated their safety for use in the spinal cord. Diffusion tensor imaging showed that with increased D90, the apparent diffusion coefficient and fractional anisotropy values were increased. Moreover, pathological damage of neurons and microvessels in the gray matter and white matter was aggravated. At 2 months after implantation, obvious pathological injury was visible in the spinal cords of each group. Magnetic resonance diffusion tensor imaging revealed the radiation injury to the spinal cord, and we quantified the degree of spinal cord injury through apparent diffusion coefficient and fractional anisotropy.

Heavy ion and X-ray irradiation alter the cytoskeleton and cytomechanics of cortical neurons

Heavy ion beams with high linear energy transfer exhibit more beneifcial physical and biological performance than conventional X-rays, thus improving the potential of this type of radiotherapy in the treatment of cancer. However, these two radiotherapy modalities both cause inevitable brain injury. The objective of this study was to evaluate the effects of heavy ion and X-ray irra-diation on the cytoskeleton and cytomechanical properties of rat cortical neurons, as well as to determine the potential mechanism of neuronal injury after irradiation. Cortical neurons from 30 new-born mice were irradiated with heavy ion beams at a single dose of 2 Gy and X-rays at a single dose of 4 Gy;subsequent evaluation of their effects were carried out at 24 hours after irradiation. An immunolfuorescence assay showed that after irradiation with both the heavy ion beam and X-rays, the number of primary neurons was signiifcantly decreased, and there was ev-idence of apoptosis. Radiation-induced neuronal injury was more apparent after X-irradiation. Under atomic force microscopy, the neuronal membrane appeared rough and neuronal rigidity had increased. These cell changes were more apparent following exposure to X-rays. Our ifnd-ings indicated that damage caused by heavy ion and X-ray irradiation resulted in the structural distortion and rearrangement of the cytoskeleton, and affected the cytomechanical properties of the cortical neurons. Moreover, this radiation injury to normal neurons was much severer after irradiation with X-rays than after heavy ion beam irradiation.

Mesenchymal stem cell therapy for acute radiation syndrome: Innovative medical approaches in military medicine

After a radiological or nuclear event, acute radiation syndrome(ARS) will present complex medical challenges that could involve the treatment of hundreds to thousands of patients. Current medical doctrine is based on limited clinical data and remains inadequate. Efforts to develop medical innovations that address ARS complications are unlikely to be generated by the industry because of market uncertainties specific to this type of injury. A prospective strategy could be the integration of cellular therapy to meet the medical demands of ARS. The most clinically advanced cellular therapy to date is the administration of mesenchymal stem cells(MSCs). Results of currently published investigations describing MSC safety and efficacy in a variety of injury and disease models demonstrate the unique qualities of this reparative cell population in adapting to the specific requirements of the damaged tissue in which the cells integrate. This report puts forward a rationale for the further evaluation of MSC therapy to address the current unmet medical needs of ARS. We propose that the exploration of this novel therapy for the treatment of the multivariate complications of ARS could be of invaluable benefit to military medicine.

Expression of Angiotensin Ⅱ and Aldosterone in Radiation-induced Lung Injury

Objective Radiation-induced lung injury （RILl） is the most common, dose-limiting complication in thoracic malignancy radiotherapy. Considering its negative impact on patients and restrictions to efficacy, the mechanism of RILl was studied. Methods Wistar rats were locally irradiated with a single dose of 0, 16, and 20 Gy to the right half of the lung to establish a lung injury model. Two and six months after irradiation, the right half of the rat lung tissue was removed, and the concentrations of TGF-[31, angiotensin II, and aldosterone were determined via enzyme-linked immunosorbent assay. Results Statistical differences were observed in the expression levels of angiotensin II and aldosterone between the non-irradiation and irradiation groups. Moreover, the expression level of the angiotensin II-aldosterone system increased with increasing doses, and the difference was still observed as time progressed. Conclusions Angiotensin II-aldosterone system has an important pathophysiological function in the progression of RILI.

Effects of Ligustrazine on Bone Marrow Microvessel Systemin the Early Period of Acute Radiation Injury in Mice

Sublethally irradiated mice were immediately treated with 250 mg/kg Ligustrazine Phosphiatis intraperitoneally twice a day for seven days, and the bone marrow sections of ulna were observed. On the 5th day, the number of bone marrow microvessels of the Ligustrazine group was much greater than that of the control group. On the 7th day, the amount of the control group decreased to normal, while the ligustrazine group was still increasing, and the microvessel area was enlarged obviously. The percentage of the hematopoietic tissue volume in bone marrow between the two groups had no significant difference in the first 7days. On the 7th day after irradiation, the peripheral neutrophilic granulocytes increased in the Ligustrazine group- The results suggested that early use of Ligustrazine after acute radiation injury might improve the blood supply of bone marrow, and be helpful for recovery of hematopoiesis.

Progress in the Pathogenesis and Treatment of Radiation-Induced Brain Injury

Malignant tumors are one of the serious public health problems that threaten the survival time of human beings.They are prone to metastasis to distant organs and the central nervous system is one of the common target organs.As it is difficult for chemotherapeutics,targeted drugs and other macromolecules to pass through the blood brain barrier(BBB),local radiation therapy is often used for treating intracranial primary or metastatic tumors.However,whether it is whole brain radiation therapy(WBRT)or stereotactic body radiation therapy(SBRT),the choice of radiation dose is limited by the side effects of radiation therapy on the surrounding normal brain tissues.Radiation-induced brain injury(RBI)can further develop into radiation necrosis(RN)in the late stage.Bevacizumab is often effective against RBI by antagonizing vascular endothelial growth factor(VEGF),but it still cannot completely reverse RN.Emerging treatment options such as human pluripotent stem-cell transplantation have made it possible to reverse the process of RN.

Differential Proteomics Reveals the Potential Injury Mechanism Induced by Heavy Ion Radiation in Mice Ovaries

In the present study, we used a proteomics approach based on a two-dimensional electrophoresis （2-DE） reference map to investigate protein expression in the ovarian tissues of pubertal Swiss-Webster mice subjected to carbon ion radiation （CIR）. Among the identified proteins, ubiquitin carboxy-terminal hydrolase L1 （UCH-L1） is associated with the cell cycle[1] and that it influences proliferation in ovarian tissues. We analyzed the expression of UCH-L1 and the proliferation marker proliferation cell nuclear antigen （PCNA） following CIR using immunoblotting and immunofluorescence. The proteomics and biochemical results provide insight into the underlying mechanisms of CIR toxicity in ovarian tissues.

Study on Oxygen Supply and Protection of Bone Marrow in Acute Radiation injured Mice

After irradiated by & Gy 60Co γ-ray, mice were intraperitoneally injected immediately with 0.2 ml 100 % compound blood-activating soup twice a day for 10 days. The in situ ulnar bone marrow partial pressure of oxygen (PbO2) was determined in vivo before, during and after irradiation respectively. The bone marrow sections in the same part were observed. Our results showed that the normal murine ulnar PbO2 was 12.72±1. 05kpa. During irradiation, the level of PbO2 decreased to 10. 78±1. 17 kpa (P＜0. 001). And 3 days after irradiation, PbO2 decreased to 9. 75±0. 52 kpa, suggesting that the commonly used 'blood-activating and stasis-eliminating' Chinese drugs could promote the rehabilitation and proliferation of bone marrow microvessels in the acute radiation injured mice, expand their areas, increase the oxygen supply of bone marrow microenviroment, thereby leading to PbO2 much higher increase than that of control group. It is also helpful in the proliferation and rehabilitation of hematopoietic cells.

Study on the Protective Effects of Compound Blood-activating Soup on Bone Marrow Hematopoietic Cells in Acute Radiation Injured Mice

After irradiation with 8 Gy 60Coγ-ray,mice were immediaterly given intraperitoneal injection of 200 mg 100 % compound blood-activating soup twice a day. On the 3rd and 7th day, the P53 gene expression of bone marrow hematopoietic cells in Chinese drug group was found to be higher than that in normal group, and it was also significantly higher than that in control group. The expression level of GADD153 gene which was not expressed in normal group was much lower in Chinese drug group than that in control group. On the 7th day after irradiation, the P53 and GADD153 gene expression levels of splenic mononuclear cells were consistent with those of bone marrow hematopoietic cells both in Chinese drug group and control group. On the 3rd and 7th day, the bone marrow hematopoietic tissue volume in Chinese drug group was higher than that in control group, with no difference found between the two groups. While on the 14th day, the difference became significant (P＜0. 01). The results showed that commonly used blood-activating and stasis-eliminating drugs may strengthen .the viability of hematopoietic cells and promote the rehabilitation of hematopoiesis by inducing wt-P53 expression to block the bone marrow hematopoietic cells in G1 phase, during which DNA could be repaired.

The effects of low-dose splenic irradiation and radiotherapy on immune system of patients with locally advanced non-small cell lung cancer

Objective： The aim of the research was to study the effects of low-dose splenic irradiation and radiotherapy on immune system of patients with locally advanced non-small cell lung cancer （NSCLC）. Methods： Twelve cases of stage III NSCLC in Tumor Radiotherapy Center of our hospital （the Affiliated Hospital of Medical College Qingdao University, China） were collected from July 2011 to July 2012; all patients were under 75 years old with clear pathology, measurable lesions and good personal statement. They were randomly divided into combined treatment group （D1 ＋ D2） and control group （D1）. The control group （D1） only received radiotherapy to the chest; combined treatment group （D1 ＋ D2） received low-dose splenic irradiation plus conventional dose irradiation. Flow cytometry was used to detect the peripheral blood T lymphocyte immune indexes of patients before, during and after the treatment, classification by five blood cell analyzer was used to determine white blood cells, neutrophils, hemoglobin and platelet count. The radiation induced toxicity including esophagitis, pneumonia and gastrointestinal reaction was observed, as well as the dose when it happened. Results： There was no significant difference in the ratio between two groups in cells CD4＋, CD8＋ and CD4＋/CD8＋ after radiotherapy （P 〉 0.05）. There was no change in these indicators in combined treatment group after treatment （P 〉 0.05）, but it decreased in control group （P 〈 0.05）. There was no significant difference in the incidences of radiation esophagitis, pneumonia, gastrointestinal reactions and bone marrow suppression between two groups （P 〉 0.05）, but the patients in combined treatment group seemed to tolerate high dose well （P 〈 0.05）. Conclusion： Low-dose splenic irradiation combined with radiotherapy to the chest can alleviate the injury degree of acute radiation induced the toxicity of locally advanced NSCLC patients, through affect the patient＇s immune function.

Effects of Zaizhang－I，A Traditional Chinese Herbal Medicine，on Hematopoietic Recovery from Radiation Injury In Mice

Effects of Zaizhang-I (ZZ-I)on the recovery of hemopoietic systems from radiation injury were investigated. Mice,irradiated with 6.0 Gy -rays,were injected i. p. once daily for 7 consecutive days with either ZZ-I or saline(0.01 ml/g body wt.). The experiments showed that ZZ-I significantly promoted the recovery of not only peripheral WBC, BMC, CFU-S and CFU-GM but also the abnormal femur micro-vessel system such as blood vessels and sinus ectasia, hyperemia and hemorrhage etc.These results suggest that ZZ-I could accelerate hemopoietic recovery from radiation injury in mice by stimulating hemopoietic stem cells and improving hemopoietic inductive microenvironment (HIM).

Effect of Ligustrazine on Expressions of Basic Fibroblast Growth Factor and Its Receptor in Bone Marrow of Mice with Acute Radiation Injury

Objective: To study the expressions of basic fibroblast growth factor (bFGF) and its receptor (bFGFR) in bone marrow of mice with acute radiation injury, and to evaluate the effect of Ligustrazine (Lt) on them. Methods: Fifty-six Kunming mice of clean grade were randomly divided into 3 groups, the normal group, the control group and the Lt group. Mice in the latter two groups were once homogeneously systemic irradiated with 6.0 Gy of 60 Co, with the absorption dose rate of 0. 56 Gy/min, then treated with saline (0.2 ml/ mice) or Lt (2 mg/mice) respectively, twice a day through gastrogavage for successive 13 days. Mice were sacrificed in batch on the 3rd, 7th and 14th day by cervical dislocation to collect the bilateral femoral bone marrow for preparing bone marrow mono-nuclear cell (BMMNC) suspension. The bFGFR expression on surface of BMMNC was determined by flow cytometry; and the bFGF expres-sion level in one side of femoral bone marrow tissue was detected by immunohistochemistry with SABC-AP assay. Results: The bFGF expression in bone marrow of mice on the 3rd, 7th and 14th day after acute radiation injury all were significantly lower than that of the normal mice (P<0.05 or P<0.01). The expressions of bFGF and bFGFR in the Lt group detected were significantly higher than that in the control group detected at the corresponding time points (P<0.05 or P < 0.01). Conclusion:By way of enhancing bFGF expression in bone marrow and bFGFR expression on surface of BMMNC to accelerate the repairing of hemopoietic micro-environment in bone marrow might be one of the mechanisms of Lt in promoting hemopoietic function reconstitution after acute radiation injury.Original article on CJITWM (Chin) 2004;24(5):439