Ionizing radiation-induced genotoxic and oxidative damage in peripheral lymphocytes and plasma of healthy donors

A comprehensive review of sensors of radiation-induced damage, radiation-induced proximal events, and cell death

Radiation, a universal component of Earth's environment, is categorized into non-ionizing and ionizing forms. While non-ionizing radiation is relatively harmless, ionizing radiation possesses sufficient energy to ionize atoms and disrupt DNA, leading to cell damage, mutation, cancer, and cell death. The extensive use of radionuclides and ionizing radiation in nuclear technology and medical applications has sparked global concern for their capacity to cause acute and chronic illnesses. Ionizing radiation induces DNA damage either directly through strand breaks and base change or indirectly by generating reactive oxygen species (ROS) and reactive nitrogen species (RNS) via radiolysis of water. This damage triggers a complex cellular response involving recognition of DNA damage, cell cycle arrest, DNA repair mechanisms, release of pro-inflammatory cytokines, and cell death. This review focuses on the mechanisms of radiation-induced cellular damage, recognition of DNA damage and subsequent activation of repair processes, and the critical role of the innate immune response in resolution of the injury. Emphasis is placed on pattern recognition receptors (PRRs) and related receptors that detect damage-associated molecular patterns (DAMPs) and initiate downstream signaling pathways. Radiation-induced cell death pathways are discussed in detail. Understanding these processes is crucial for developing strategies to mitigate the harmful effects of radiation and improve therapeutic outcomes.

Biomarkers of mitochondrial stress and DNA damage during pediatric catheter-directed neuroangiography - a prospective single-center study

BACKGROUND

Neuroangiography represents a critical diagnostic and therapeutic imaging modality whose associated radiation may be of concern in children. The availability of in vivo radiation damage markers would represent a key advancement for understanding radiation effects and aid in the development of radioprotective strategies.

OBJECTIVE

Determine if biomarkers of cellular damage can be detected in the peripheral blood mononuclear cells (PBMC) of children undergoing neuroangiography.

MATERIALS AND METHODS

Prospective single-site study of 27 children. Blood collected pre and post neuroangiography, from which PBMC were isolated and assayed for biomarkers of mitochondrial stress (mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and mitochondrial DNA (mtDNA)) and DNA damage (γH2AX). Dose response of biomarkers vs. radiation dose was analyzed using linear regressions. The cohort was divided into higher (HD) and lower dose (LD) groups and analyzed using linear mixed models and compared using Welch's t-tests.

RESULTS

No biomarker exhibited a dose-dependent response following radiation (γH2AX: R2 = 0.0012, P = 0.86; MMP: R2 = 0.016, P = 0.53; mtDNA: R2 = 0.10, P = 0.11; ROS: R2 = 0.0023, P = 0.81). Groupwise comparisons showed no significant differences in γH2AX or ROS after radiation (γH2AX: LD: 0.6 ± 6.0, P = 0.92; HD: -7.5 ± 6.3 AU, P = 0.24; ROS: LD: 1.3 ± 2.8, P = 0.64; HD: -3.6 ± 3.0 AU, P = 0.24). Significant changes were observed to mitochondrial markers MMP (-53.7 ± 14.7 AU, P = 0.0014) and mtDNA (-1.1 ± 0.4 AU, P = 0.0092) for HD, but not the LD group (MMP: 26.1 ± 14.7 AU, P = 0.090; mtDNA: 0.2 ± 0.4, P = 0.65).

CONCLUSIONS

Biomarkers of mitochondrial stress in PBMC were identified during pediatric neuroangiography and warrant further investigation for radiation biodosimetry. However, isolating radiation-specific effects from those of procedural stress and general anesthesia requires further investigation.

Nanodrugs with intrinsic radioprotective exertion: Turning the double-edged sword into a single-edged knife

Ionizing radiation (IR) poses a growing threat to human health, and thus ideal radioprotectors with high efficacy and low toxicity still receive widespread attention in radiation medicine. Despite significant progress made in conventional radioprotectants, high toxicity, and low bioavailability still discourage their application. Fortunately, the rapidly evolving nanomaterial technology furnishes reliable tools to address these bottlenecks, opening up the cutting-edge nano-radioprotective medicine, among which the intrinsic nano-radioprotectants characterized by high efficacy, low toxicity, and prolonged blood retention duration, represent the most extensively studied class in this area. Herein, we made the systematic review on this topic, and discussed more specific types of radioprotective nanomaterials and more general clusters of the extensive nano-radioprotectants. In this review, we mainly focused on the development, design innovations, applications, challenges, and prospects of the intrinsic antiradiation nanomedicines, and presented a comprehensive overview, in-depth analysis as well as an updated understanding of the latest advances in this topic. We hope that this review will promote the interdisciplinarity across radiation medicine and nanotechnology and stimulate further valuable studies in this promising field.

PARADOXICAL DUAL ROLES OF SOME CYTOKINES INTERPRETED BY CYTOGENETICS INVESTIGATIONS IN IRRADIATED HUMAN BLOOD CULTURES

Four different cytokines (IL1-β, IL-6, IL-10 and TNF-α) and the cytokinesis-block micronucleus (CBMN) cytome assay investigations were evaluated in six human blood samples. They were divided into the control (nonirradiated) and five gamma-irradiated groups which were exposed to five different doses (0.5, 1, 2, 4 and 8 Gy). Blood groups were cultured in triplets for 72 h following 1 h of irradiation. Immunological and cytogenetics were investigated parallelly at different irradiation doses to understand the connection between them. Our aim is anchoring the active proliferation action of cytokines by presence of binucleated cells and resting immune system by mononuclear cell. Also, cell death by increasing necrotic cell count and TNF-α concentration. When compared with the control group, 0.5, 1, 2 and 4 Gy irradiation groups recorded a gradual increase in the cytokines levels, an increase in the total micronucleated cells (binucleated and mononucleated cells), an increase in necrotic and apoptotic cells counts. While 8 Gy irradiation leads to depletion in TNF-α concentration, although the number of necrotic cells was high.

Metabolic Rewiring in Radiation Oncology Toward Improving the Therapeutic Ratio

To meet the anabolic demands of the proliferative potential of tumor cells, malignant cells tend to rewire their metabolic pathways. Although different types of malignant cells share this phenomenon, there is a large intracellular variability how these metabolic patterns are altered. Fortunately, differences in metabolic patterns between normal tissue and malignant cells can be exploited to increase the therapeutic ratio. Modulation of cellular metabolism to improve treatment outcome is an emerging field proposing a variety of promising strategies in primary tumor and metastatic lesion treatment. These strategies, capable of either sensitizing or protecting tissues, target either tumor or normal tissue and are often focused on modulating of tissue oxygenation, hypoxia-inducible factor (HIF) stabilization, glucose metabolism, mitochondrial function and the redox balance. Several compounds or therapies are still in under (pre-)clinical development, while others are already used in clinical practice. Here, we describe different strategies from bench to bedside to optimize the therapeutic ratio through modulation of the cellular metabolism. This review gives an overview of the current state on development and the mechanism of action of modulators affecting cellular metabolism with the aim to improve the radiotherapy response on tumors or to protect the normal tissue and therefore contribute to an improved therapeutic ratio.