Correction: Lenarczyk et al. T Cells Contribute to Pathological Responses in the Non-Targeted Rat Heart following Irradiation of the Kidneys. Toxics 2022, 10, 797

In the original publication [...

Abstract 24082: A Combined Basic Science and PopulationScience Approach Demonstrating the Potential for Simvastatin to MitigateCardiovascular Disease after Lower Hemi Body Radiotherapy

Radiation is a cornerstone of successful cancer treatment, with one-half to two-thirds of all patients receiving radiotherapy. Survivors of cancer treated with radiation are at increased risk for cardiovascular disease (CVD). Understanding how radiation causes CVD will allow development of novel therapies. Irradiation of the lower hemi body, but not the upper hemi body, with 10 Gy in rats increases risk factors for CVD and results in cardiac fibrosis quantitatively similar to total body irradiation, suggesting radiation injury to the heart can be indirect. Simvastatin, an inhibitor of liver cholesterol synthesis administered continuously to rats (10 mg/kg/day) after 10 Gy lower hemi body irradiation mitigated against increased blood cholesterol and cardiac fibrosis. These findings indicate simvastatin limits transmission of a signal from the lower hemi body that decreases risk for and occurrence of CVD independent of any direct exposure of the heart to radiation. Bivariate examination of 3,607 patients following therapeutic lower hemi body irradiation using Chi-square, Wilcoxon rank-sum and t-tests was used to examine risk factors for CVD in patients diagnosed with congestive heart failure, myocardial infarction, atrial fibrillation, and cardiomyopathy before 80 years of age. We found that 47.4% of patients age 70-80 developed CVD compared to 29.7% who received simvastatin (p= &lt; 0.001, n = 293 and 361, respectively). Patients who were male, overweight, smokers, and had a diagnosis of chronic kidney disease and diabetes also had significantly higher risk of CVD. Race and hypertension were not indicative of increased risk for CVD. These clinical findings, taken together with the results from our animal studies, support a new research paradigm where radiation-induced heart disease can be indirect, with abdominal organs exporting factors that cause CVD. Simvastatin can be developed to mitigate and treat CVD after therapeutic radiation.</jats:p

Exposure to multiple ion beams, broadly representative of galactic cosmic rays, causes perivascular cardiac fibrosis in mature male rats

Long-duration space exploratory missions to the Earth's moon and the planet Mars are actively being planned. Such missions will require humans to live for prolonged periods beyond low earth orbit where astronauts will be continuously exposed to high energy galactic cosmic rays (GCRs). A major unknown is the potential impact of GCRs on the risks of developing degenerative cardiovascular disease, which is a concern to NASA. A ground-based rat model has been used to provide a detailed characterization of the risk of long-term cardiovascular disease from components of GCRs at radiation doses relevant to future human missions beyond low earth orbit. Six month old male WAG/RijCmcr rats were irradiated at a ground-based charged particle accelerator facility with high energy ion beams broadly representative of GCRs: protons, silicon and iron. Irradiation was given either as a single ion beam or as a combination of three ion beams. For the doses used, the single ion beam studies did not show any significant changes in the known cardiac risk factors and no evidence of cardiovascular disease could be demonstrated. In the three ion beam study, the total cholesterol levels in the circulation increased modestly over the 270 day follow up period, and inflammatory cytokines were also increased, transiently, 30 days after irradiation. Perivascular cardiac collagen content, systolic blood pressure and the number of macrophages found in the kidney and in the heart were each increased 270 days after irradiation with 1.5 Gy of the three ion beam grouping. These findings provide evidence for a cardiac vascular pathology and indicate a possible threshold dose for perivascular cardiac fibrosis and increased systemic systolic blood pressure for complex radiation fields during the 9 month follow up period. The development of perivascular cardiac fibrosis and increased systemic systolic blood pressure occurred at a physical dose of the three ion beam grouping (1.5 Gy) that was much lower than that required to show similar outcomes in earlier studies with the same rat strain exposed to photons. Further studies with longer follow up periods may help determine whether humans exposed to lower, mission-relevant doses of GCRs will develop radiation-induced heart disease