Gut Microbiota-Derived PGF2α Fights against Radiation-Induced Lung Toxicity through the MAPK/NF-κB Pathway

Radiation pneumonia is a common and intractable side effect associated with radiotherapy for chest cancer and involves oxidative stress damage and inflammation, prematurely halting the remedy and reducing the life quality of patients. However, the therapeutic options for the complication have yielded disappointing results in clinical application. Here, we report an effective avenue for fighting against radiation pneumonia. Faecal microbiota transplantation (FMT) reduced radiation pneumonia, scavenged oxidative stress and improved lung function in mouse models. Local chest irradiation shifted the gut bacterial taxonomic proportions, which were preserved by FMT. The level of gut microbiota-derived PGF2α decreased following irradiation but increased after FMT. Experimental mice with PGF2α replenishment, via an oral route, exhibited accumulated PGF2α in faecal pellets, peripheral blood and lung tissues, resulting in the attenuation of inflammatory status of the lung and amelioration of lung respiratory function following local chest irradiation. PGF2α activated the FP/MAPK/NF-κB axis to promote cell proliferation and inhibit apoptosis with radiation challenge; silencing MAPK attenuated the protective effect of PGF2α on radiation-challenged lung cells. Together, our findings pave the way for the clinical treatment of radiotherapy-associated complications and underpin PGF2α as a gut microbiota-produced metabolite.

Gut Microbiota-Derived l-Histidine/Imidazole Propionate Axis Fights against the Radiation-Induced Cardiopulmonary Injury

Radiation-induced cardiopulmonary injuries are the most common and intractable side effects that are entwined with radiotherapy for thorax cancers. However, the therapeutic options for such complications have yielded disappointing results in clinical applications. Here, we reported that gut microbiota-derived l-Histidine and its secondary metabolite imidazole propionate (ImP) fought against radiation-induced cardiopulmonary injury in an entiric flora-dependent manner in mouse models. Local chest irradiation decreased the level of l-Histidine in fecal pellets, which was increased following fecal microbiota transplantation. l-Histidine replenishment via an oral route retarded the pathological process of lung and heart tissues and improved lung respiratory and heart systolic function following radiation exposure. l-Histidine preserved the gut bacterial taxonomic proportions shifted by total chest irradiation but failed to perform radioprotection in gut microbiota-deleted mice. ImP, the downstream metabolite of l-Histidine, accumulated in peripheral blood and lung tissues following l-Histidine replenishment and protected against radiation-induced lung and heart toxicity. Orally gavaged ImP could not enter into the circulatory system in mice through an antibiotic cocktail treatment. Importantly, ImP inhibited pyroptosis to nudge lung cell proliferation after radiation challenge. Together, our findings pave a novel method of protection against cardiopulmonary complications intertwined with radiotherapy in pre-clinical settings and underpin the idea that gut microbiota-produced l-Histidine and ImP are promising radioprotective agents.

Neutrophil-to-lymphocyte ratio can predict outcome in extensive-stage small cell lung cancer

BackgroundThe neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) were analyzed in various carcinomas and their potential prognostic significance was determined. The objective of present study was to determine the correlation between these parameters and the survival of patients with small cell lung cancer (SCLC), since very few studies have been published on this type of carcinoma.Patients and methodsOne hundred and forty patients diagnosed with SCLC at University Hospital Center Zagreb, between 2012 and 2016 were retrospectively analyzed. Extensive-stage disease (ED) was verified in 80 patients and limited-stage disease (LD) in 60 patients. We analyzed the potential prognostic significance of various laboratory parameters, including NLR, PLR, and LMR, measured before the start of treatment.ResultsDisease extension, response to therapy, chest irradiation and prophylactic cranial irradiation (PCI), as well as hemoglobin, monocyte count, C-reactive protein (CRP), and lactate dehydrogenase (LDH) showed a prognostic significance in all patients. When we analyzed the patients separately, depending on the disease extension, we found that only skin metastases as well as LDH and NLR values, regardless of the cut-off value, had a prognostic significance in ED. Meanwhile, the ECOG performance status, chest irradiation, PCI, and hemoglobin and creatinine values had a prognostic significance in LD.ConclusionsNLR calculated before the start of the treatment had a prognostic significance for ED, while PLR and LMR had no prognostic significance in any of the analyzed groups of patients.

Breast cancer after chest irradiation for lymphoma: case report

Breast cancer is one of the most common diseases among women worldwide. One of the risk factors for the development of this neoplasia is previous radiotherapy on the chest wall. Breast cancer, in turn, is the main long-term concern among women treated for lymphoma with radiation on the chest wall. Thus, we present a case of breast cancer that appeared 18 years after chest radiation for the treatment of lymphoma.

Radiation-Induced Dual Oxidase Upregulation in Rat Heart Tissues: Protective Effect of Melatonin

Background: Radiation-induced heart injury can lead to increased risk of heart failure, attack, and ischemia. Some studies proposed IL-4 and IL-13 as two important cytokines that are involved in late effects of ionizing radiation. On the other hand, these cytokines may, through upregulation of Duox1 and Duox2, induce chronic oxidative stress, inflammation, and fibrosis. In this study, we evaluated the upregulation of Duox1 and Duox2 pathways in hearts following chest irradiation in rats and then detected possible attenuation of them by melatonin. Materials and Methods: Twenty male Wistar rats were divided into four groups: (1) control; (2) melatonin treated (100 mg/kg); (3) radiation (15 Gy gamma rays); (4) melatonin treated before irradiation. All rats were sacrificed after 10 weeks and their heart tissues collected for real-time PCR (RT-PCR), ELISA detection of IL-4 and IL-13, as well as histopathological evaluation of macrophages and lymphocytes infiltration. Results: Results showed an upregulation of IL-4, IL4ra1, Duox1, and Duox2. The biggest changes were for IL4ra1 and Duox1. Treatment with melatonin before irradiation could attenuate the upregulation of all genes. Melatonin also caused a reduction in IL-4 as well as reverse infiltration of inflammatory cells. Conclusion: Duox1 and Duox2 may be involved in the late effects of radiation-induced heart injury. Also, via attenuation of these genes, melatonin can offer protection against the toxic effects of radiation on the heart.

Prevention of radiotherapy-induced arterial inflammation by interleukin-1 blockade

Aims Radiotherapy-induced cardiovascular disease is an emerging problem in a growing population of cancer survivors where traditional treatments, such as anti-platelet and lipid-lowering drugs, have limited benefits. The aim of the study was to investigate vascular inflammatory patterns in human cancer survivors, replicate the findings in an animal model, and evaluate whether interleukin-1 (IL-1) inhibition could be a potential treatment. Methods and results Irradiated human arterial biopsies were collected during microvascular autologous free tissue transfer for cancer reconstruction and compared with non-irradiated arteries from the same patient. A mouse model was used to study the effects of the IL-1 receptor antagonist, anakinra, on localized radiation-induced vascular inflammation. We observed significant induction of genes associated with inflammasome biology in whole transcriptome analysis of irradiated arteries, a finding supported by elevated protein levels in irradiated arteries of both, pro-caspase and caspase-1. mRNA levels of inflammasome associated chemokines CCL2, CCL5 together with the adhesion molecule VCAM1, were elevated in human irradiated arteries as was the number of infiltrating macrophages. A similar pattern was reproduced in Apoe−/− mouse 10 weeks after localized chest irradiation with 14 Gy. Treatment with anakinra in irradiated mice significantly reduced Ccl2 and Ccl5 mRNA levels and expression of I-Ab. Conclusion Anakinra, administered directly after radiation exposure for 2 weeks, ameliorated radiation induced sustained expression of inflammatory mediators in mice. Further studies are needed to evaluate IL-1 blockade as a treatment of radiotherapy-induced vascular disease in a clinical setting.

Radiation induced valvular disease: the internist’s prospective

Radiation-induced cardiac injury entails a wide spectrum of cardiovascular complications such as cardiomyopathy and valvular diseases among others. We present the internist’s perspective and the challenges faced in managing these patients. There are guidelines addressing radiation-induced valvular disease (RIVD) including screening and treatment, but are often unrecognised by most internist’s practice. A thorough cardiovascular examination and screening echocardiography may detect RIVD at an earlier stage. Early screening with transthoracic echocardiogram should be considered in asymptomatic or low-risk patients and more frequently in symptomatic and high-risk patients. The internists should educate their patients with prior chest irradiation, regarding the possible radiation related adverse cardiovascular effects and recommended screening. Lifestyle changes and aggressive cardiovascular risk modification should be emphasised, as concomitant hypertension, coronary artery disease and cardiomyopathy can have unfavourable effects in these patients.