The Oxidative Stress Parameters as Useful Tools in Evaluating the DNA Damage and Changes in the Complete Blood Count in Hospital Workers Exposed to Low Doses of Antineoplastic Drugs and Ionizing Radiation

Evaluating oxidative stress biomarkers in oncology nurses exposed to antineoplastic drugs: A cross-sectional study

PURPOSE

Antineoplastic drugs (ADs) are widely used in cancer treatment. Nurses in chemotherapy centers are exposed to these drugs during preparation. They can affect healthy cells, leading to teratogenic and mutagenic effects, as well as oxidative stress. This study aimed to evaluate oxidative stress biomarkers in the nurses exposed to these drugs.

METHOD

This study was conducted on 30 nurses exposed to ADs and 30 nurses with no exposure to these drugs as non-exposed group. Oxidative stress biomarkers were measured in the blood serum samples of both groups, including malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), total antioxidant capacity (TAC), and blood thiol groups.

RESULTS

Considering the possibility of confounding effect of nutritional supplement consumption, the effect of this factor was adjusted in the analysis. A significant difference was observed for CAT, SOD, thiol, and TAC biomarkers between two groups (P < 0.05). However, the difference in MDA and GPx biomarkers between two groups was not statistically significant.

CONCLUSIONS

The findings of the present study showed that supplement consumption has a significant effect on the biomarker of total antioxidant capacity. Thus, total antioxidant capacity measurement is advised as the best biomarker for tracking oxidative status in nurses exposed to ADs due to its capacity to measure all antioxidants in the body, except the thiol group, and its lower cost when compared to other biomarkers. Furthermore, it can be claimed that the consumption of nutritional supplements has a greater effect on the non-enzymatic biomarkers of oxidative stress than on enzymatic antioxidant system.

Mitigation of Fetal Irradiation Injury from Mid-Gestation Total Body Radiation with Mitochondrial-Targeted GS-Nitroxide JP4-039

Victims of a radiation terrorist event will include pregnant women and unborn fetuses. Mitochondrial dysfunction and oxidative stress are key pathogenic factors of fetal irradiation injury. The goal of this preclinical study is to investigate the efficacy of mitigating fetal irradiation injury by maternal administration of the mitochondrial-targeted gramicidin S (GS)- nitroxide radiation mitigator, JP4-039. Pregnant female C57BL/6NTac mice received 3 Gy total body ionizing irradiation (TBI) at mid-gestation embryonic day 13.5 (E13.5). Using novel time- and-motion-resolved 4D in utero magnetic resonance imaging (4D-uMRI), we found TBI caused extensive injury to the fetal brain that included cerebral hemorrhage, loss of cerebral tissue, and hydrocephalus with excessive accumulation of cerebrospinal fluid (CSF). Histopathology of the fetal mouse brain showed broken cerebral vessels and elevated apoptosis. Further use of novel 4D Oxy-wavelet MRI capable of probing in vivo mitochondrial function in intact brain revealed significant reduction of mitochondrial function in the fetal brain after 3Gy TBI. This was validated by ex vivo Oroboros mitochondrial respirometry. Maternal administration JP4-039 one day after TBI (E14.5), which can pass through the placental barrier, significantly reduced fetal brain radiation injury and improved fetal brain mitochondrial respiration. This also preserved cerebral brain tissue integrity and reduced cerebral hemorrhage and cell death. As JP4-039 administration did not change litter sizes or fetus viability, together these findings indicate JP4-039 can be deployed as a safe and effective mitigator of fetal radiation injury from mid-gestational in utero ionizing radiation exposure.

One Sentence Summary

Mitochondrial-targeted gramicidin S (GS)-nitroxide JP4-039 is safe and effective radiation mitigator for mid-gestational fetal irradiation injury.

Systematic review of genotoxicity induced by occupational exposure to antineoplastic drugs

With increasing numbers of cancer cases, the use of antineoplastic agents is expected to rise. This will be accompanied by an increase in occupational exposure, which can cause unwanted health effects in workers. Our aim was to give an overview of genotoxic and epigenetic effects after occupational exposure to antineoplastic agents and to assess the concentration-effect relation. Four databases were searched for papers investigating genotoxic and/or epigenetic effects of occupational exposure to antineoplastic agents. Out of the 245 retrieved papers, 62 were included in this review. In this systematic literature review, we confirmed that exposure of healthcare workers to antineoplastic agents can lead to genotoxic damage. However, we observed a lack of data on exposure as well as genotoxic and epigenetic effects in workers other than healthcare workers. Furthermore, gaps in the current knowledge regarding the potential epigenetic effects caused by antineoplastic drug exposure and regarding the link between internal antineoplastic drug concentration and genotoxic and epigenetic effects after occupational exposure to antineoplastic agents were identified, offering a first step for future research.

Receiver Operator Characteristic (ROC) Analysis of Lipids, Proteins, DNA Oxidative Damage, and Antioxidant Defense in Plasma and Erythrocytes of Young Reproductive-Age Men with Early Stages of Type 1 Diabetes Mellitus (T1DM) Nephropathy in the Irkutsk Region, Russia

Oxidative stress plays a leading role in the pathogenesis of diabetic nephropathy. However, many aspects of oxidative stress reactions in the initial stages of this disease are not fully understood. The men cohort is of particular interest because of the severe effects of diabetes on their urogenital system. The aim of this study is to assess the intensity of lipids, proteins, DNA oxidative damage, blood antioxidant defense enzymatic, and activity of non-enzymatic components in men with type 1 diabetes mellitus (T1DM) in the early stages of diabetic nephropathy using receiver operator characteristic (ROC) analysis. This study included eighty-nine reproductive-age men in the initial stages of diabetic nephropathy (DN) and thirty-nine age- and sex-matched individuals not suffering from glycemic disorders. The DN patients were divided into two subgroups: stage 1 patients (urinary albumin < 30 mg/day and albumin/creatinine ratio < 3 mg/mmol (n = 45)) and stage 2 patients (urinary albumin 30−300 mg/day and albumin/creatinine ratio 3−30 mg/mmol (n = 44)). Levels of oxidative damage products (conjugated dienes (CDs), thiobarbituric acid reactants (TBARs), methylglyoxal (MGO), and 8-hydroxy-2’-deoxyguanosine (8-OHdG)) and antioxidants (glutathione peroxidase (GPx), glutathione S-transferases π (GSTp), glutathione reductase (GR), copper and zinc-containing superoxide dismutase 1 (SOD-1), total antioxidant status (TAS), α-tocopherol, retinol, reduced glutathione (GSH), and oxidative glutathione (GSSG)) were estimated in plasma and erythrocytes. Oxidative damage to cellular structures (higher values of median CDs (1.68 µmol/L; p = 0.003), MGO (3.38 mg/L; p < 0.001) in the stage 1 group and CDs (2.28 µmol/L; p < 0.0001), MGO (3.52 mg/L; p < 0.001), 8-OHdG (19.44 ng/mL; p = 0.010) in the stage 2 group) and changes in the antioxidant defense system (lower values of TAS (1.14 units; p = 0.011), α-tocopherol (12.17 µmol/L; p = 0.009), GPx (1099 units; p = 0.0003) and elevated levels of retinol (1.35 µmol/L; p < 0.001) in the group with stage 1; lower values of α-tocopherol (12.65 µmol/L; p = 0.033), GPx (1029.7 units; p = 0.0001) and increased levels of GR (292.75 units; p < 0.001), GSH (2.54 mmol/L; p = 0.010), GSSG (2.31 mmol/L; p < 0.0001), and retinol (0.81 µmol/L; p = 0.005) in the stage 2 group) were identified. The ROC analysis established that the following indicators have the highest diagnostic significance for stage 1 diabetic nephropathy: CDs (AUC 0.755; p < 0.0001), TBARs (AUC 0.748; p = 0.0001), MGO (AUC 0.720; p = 0.0033), retinol (AUC 0.932; p < 0.0001), GPx (AUC 0.741; p = 0.0004), α-tocopherol (AUC 0.683; p = 0.0071), and TAS (AUC 0.686; p = 0.0052) and the following for stage 2 diabetic nephropathy: CDs (AUC 0.714; p = 0.001), TBARs (AUC 0.708; p = 0.001), 8-OHdG (AUC 0.658; p = 0.0232), GSSG (AUC 0.714; p = 0.001), and GSH (AUC 0.667; p = 0.0108). We conclude that changes in indicators of damage to lipids, proteins, DNA, and the insufficiency of antioxidant defense factors already manifest in the first stage of diabetic nephropathy in men with T1DM. The ROC established which parameters have the greatest diagnostic significance for stages 1 and 2 of diabetic nephropathy, which may be utilized as additional criteria for defining men with T1DM as being in the risk group for the development of initial manifestations of the disease and thus allow for substantiating appropriate approaches to optimize preventive measures.

Amelioration of Radiation-Induced Cell Death in Neuro2a Cells by Neutralizing Oxidative Stress and Reducing Mitochondrial Dysfunction Using N-Acetyl-L-Tryptophan

The deleterious effects of ionizing radiation on the central nervous system (CNS) are poorly understood. Radiation exposure during an accidental nuclear explosion, nuclear war, or radiotherapy causes severe brain damage. As a result, the current work is carried out to assess the radioprotective potential of N-acetyl-L-tryptophan (L-NAT) in neuronal cells. Radiation-induced cell death and its amelioration by L-NAT pretreatment were investigated using MTT, SRB, CFU, and comet assays. Flow cytometric and microscopic fluorescence assays were used to investigate radiation-induced oxidative stress, alteration in mitochondrial redox, Ca2+ homeostasis, depolarization of mitochondrial membrane potential, and its prevention with L-NAT pretreatment. Western blot analysis of Caspase-3, γ-H2aX, p53, ERK-1/2, and p-ERK-1/2 expression was carried out to identify the effects of L-NAT pretreatment on radiation-induced apoptosis and its regulatory proteins expression. The study demonstrated (MTT, SRB, and CFU assay) significant (~80%; p <0.001%) radioprotection in irradiated (LD50 IR dose) Neuro2a cells that were pretreated with L-NAT. In comparison to irradiated cells, L-NAT pretreatment resulted in significant (p <0.001%) DNA protection. A subsequent study revealed that L-NAT pretreatment of irradiated Neuro2a cells establishes oxidative stress by increasing antioxidant enzymes and mitochondrial redox homeostasis by inhibiting Ca2+ migration from the cytoplasm to the mitochondrial matrix and thus protects the mitochondrial membrane hyperpolarization. Caspase-3 and γ-H2aX protein expression decreased, while p-ERK1/2 and p53 expression increased in L-NAT pretreated irradiated cells compared to irradiated cells. Hence, L-NAT could be a potential radioprotective that may inhibit oxidative stress and DNA damage and maintain mitochondrial health and Ca2+ levels by activating p-ERK1/2 and p53 expression in Neuronal cells.

The effect of respiratory capacity for dose sparing in left-sided breast cancer irradiation with active breathing coordinator technique

Background and aim

A subsequent cardiac toxicity is deemed to be dose-dependent for left-sided breast cancer irradiation. This study aims to demonstrate the effect of respiratory capacity for dose sparing when the deep inspiration breath hold with Active Breathing Coordinator technique (ABC-DIBH) is used in left-sided breast cancer irradiation.

Methods

74 left-sided breast cancer patients, who received whole breast or post-mastectomy chest wall radiotherapy with ABC-DIBH between 2020 and 2021 in our center, were retrospectively reviewed in this study. CT scans of free breath (FB) and ABC-DIBH were done for each patient, and two treatment plans with a prescription dose of 5000 cGy/25 Fr were designed separately. The dose to heart, left anterior descending artery (LAD) and lungs was compared between FB and ABC-DIBH. The correlation between individual parameters (dose to organs at risk (OARs) and minimum heart distance (MHD)) was analyzed, and the effect of respiratory capacity for dose sparing was assessed.

Results

The plans with ABC-DIBH achieved lower Dmean for heart (34.80%, P &lt; 0.01) and LAD (29.33%, P &lt; 0.01) than those with FB. Regression analysis revealed that both Dmean and D2 of heart were negatively correlated with MHD in the plans with FB and ABC-DIBH, which decreased with the increase in MHD by 37.8 cGy and 309.9 cGy per 1mm, respectively. Besides, a lower Dmean of heart was related to a larger volume of ipsilateral lung in plans with FB. With the increase in volume of ipsilateral lung, the linear correlation was getting weaker and weaker until the volume of ipsilateral lung reached 1700 cc. Meanwhile, a negative linear correlation between Dmean of LAD and MHD in plans with FB and ABC-DIBH was observed, whose slope was 162.5 and 135.9 cGy/mm, respectively. Furthermore, when the respiratory capacity of ABC-DIBH reached 1L, and the relative ratio (ABC-DIBH/FB) reached 3.6, patients could obtain the benefit of dose sparing. The larger difference in respiratory capacity had no significant effect in the larger difference of MHD, Dmean of heart and Dmean of LAD between FB and ABC-DIBH.

Conclusion

This study demonstrates the sufficiently good effect of ABC-DIBH when utilizing for cardiac sparing. It also reveals the correlations among individual parameters and the effect of respiratory capacity for dose sparing. This helps take optimal advantage of the ABC-DIBH technique and predict clinical benefits.

Hematological parameters and X-ray exposure among medical radiation workers: a systematic review and meta-analysis

BACKGROUND

The aim of this study was to explore the effect of occupational exposure to X-ray on hematological parameters.

RESEARCH DESIGN AND METHODS

A systematic search was conducted in the Scopus, PubMed, Web of Science, and Embase databases up to April 2020. The methodological quality was assessed by the 10-item Joanna Briggs Institute (JBI) Critical Appraisal Checklist for case-control studies. The random-effects model was used to estimate the effect size (standard difference in means (SDMs)).

RESULTS

Out of 1750 identified citations, ten studies met the inclusion criteria and were included in the meta-analysis. The overall effect size did not show any significant difference between the two groups (SMDs ranged from -0.382±0.29 for white blood cells (WBC), 0.213±0.40 for platelet, -0.323±0.0.16 for mean corpuscular volume (MCV), 0.553±0.41 for mean corpuscular hemoglobin concentration (MCHC), -1.615±1.41 for monocyte, 0.418±0.49 for lymphocyte (P-value>0.05). Only the effect size of red blood cells was significantly higher than that of the control group (SMD= 1.06±0.28; 95% CI: 0.504, 1.615; P-value=0.001).

CONCLUSION

The long-term and low-dose radiation may have no significant effect on blood parameters. Future studies are suggested to use other tests such as dicentric chromosome assay (DCA), cytogenetic tests, and modern tests besides blood count parameters.

Exposure to Antineoplastic Drugs in Occupational Settings: A Systematic Review of Biological Monitoring Data

The high toxicity of antineoplastic drugs (ADs) makes them dangerous not only for patients, but also for exposed workers. Therefore, the aim of this review was to provide an updated overview of the biological monitoring of occupational AD exposure in order to extrapolate information useful to improve risk assessment and management strategies in workplaces. Several studies demonstrated that remarkable portions of healthcare workers may have traces of these substances or their metabolites in biological fluids, although with some conflicting results. Nurses, directly engaged in AD handling, were the occupational category at higher risk of contamination, although, in some cases, personnel not involved in AD-related tasks also showed quantifiable internal doses. Overall, further research carried out on greater sample sizes appears necessary to gain deeper insight into the variability retrieved in the reported results. This may be important to understand the impact of the extent of ADs use, different handling, procedures, and cleaning practices, spill occurrence, training of the workforce, as well as the adoption of adequate collective and personal protective equipment in affecting the occupational exposure levels. This may support the achievement of the greatest clinical efficiency of such therapies while assuring the health and safety of involved workers.