Redox status in workers occupationally exposed to long-term low levels of ionizing radiation: A pilot study

Population Studies and Molecular Mechanisms of Human Radioadaptive Capabilities: Is It Time to Rethink Radiation Safety Standards?

The evolution of man on Earth took place under conditions of constant exposure to background ionizing radiation (IR). From this point of view, it would be reasonable to hypothesize the existence of adaptive mechanisms that enable the human organism to safely interact with IR at levels approximating long-term natural background levels. In some situations, the successful operation of molecular mechanisms of protection against IR is observed at values significantly exceeding the natural background level, for example, in cancer cells. In 15-25% of cancer patients, cancer cells develop a phenotype that is resistant to high doses of IR. While further investigations are warranted, the current evidence suggests a strong probability of observing positive health effects, including an increased lifespan, a reduced cancer risk, and a decreased incidence of congenital pathologies, precisely at low doses of ionizing radiation. This review offers arguments primarily based on a phenomenological approach and critically reconsidering existing methodologies for assessing the biological risks of IR to human health. Currently, in the most economically developed countries, there are radiation safety rules that interpret low-dose radiation as a clearly negative environmental factor. Nowadays, this approach may pose significant challenges to the advancement of radiomedicine and introduce complexities in the regulation of IR sources. The review also examines molecular mechanisms that may play a key role in the formation of the positive effects of low-dose IR on human radioadaptive capabilities.

Blood oxidative stress parameters in hospital workers occupationally exposed to low doses of ionizing radiation: A systematic review and meta-analysis

This study conducted a systematic review and meta-analysis to explore the relationship between blood oxidative stress biomarkers and exposure to low-dose ionizing radiation in medical radiation workers. The researchers searched PubMed, Scopus, Web of Science, and Google Scholar for relevant studies until February 2023. They assessed the quality of the studies using the Newcastle‒Ottawa Scale (NOS) and used a random-effects model to combine the results. The I-square test was employed to assess study heterogeneity. The effect sizes were represented by standardized mean differences (proxied by Hedges' g) with a 95 % confidence interval. Out of 295 initial articles, 38 studies met the inclusion criteria for the meta-analysis. The systematic review results revealed a significant difference in blood oxidative stress biomarkers with exposure to low-dose ionizing radiation in medical radiation workers. Furthermore, the overall effect size of MDA was notably higher than that of the control group (p < 0.05). However, the effect size did not show any significant difference between the two groups for other parameters (SMDs ranged from [-0.92, 2.10] for 8-OHdG, [-3.47, 4.48] for reduced glutathione, [-1.08, 3.61] for CAT, [-5.03, 18.35] for SOD, [-2.52, 2.56] for TAC (p > 0.05)).

Clinical markers of HIV predict redox-regulated neural and behavioral function in the sensorimotor system

Even in the modern era of combination antiretroviral therapy, aberrations in motor control remain a predominant symptom contributing to age-related functional dependencies (e.g., neurocognitive impairment) in people with HIV (PWH). While recent evidence implicates aberrant mitochondrial redox environments in the modulation of neural oscillatory activity serving motor control in PWH, the contribution of important clinical and demographic factors on this bioenergetic-neural-behavioral pathway is unknown. Herein, we evaluate the predictive capacity of clinical metrics pertinent to HIV (e.g., CD4 nadir, time with viremia) and age on mitochondrial redox-regulated sensorimotor brain-behavior dynamics in 69 virally-suppressed PWH. We used state-of-the-art systems biology and neuroscience approaches, including Seahorse analyzer of mitochondrial energetics, EPR spectroscopy of intracellular oxidant levels, antioxidant activity assays pertinent to superoxide and hydrogen peroxide (H2O2) redox environments, and magnetoencephalographic (MEG) imaging to quantify sensorimotor oscillatory dynamics. Our results demonstrate differential effects of redox systems on the neural dynamics serving motor function in PWH. In addition, measures of immune stability and duration of compromise due to HIV had dissociable effects on this pathway, above and beyond the effects of age alone. Moreover, peripheral measures of antioxidant activity (i.e., superoxide dismutase) fully mediated the relationship between immune stability and current behavioral performance, indicative of persistent oxidative environments serving motor control in the presence of virologic suppression. Taken together, our data suggest that disease-related factors, in particular, are stronger predictors of current redox, neural and behavioral profiles serving motor function, which may serve as effective targets for alleviating HIV-specific alterations in cognitive-motor function in the future.

Protection against cancer therapy-induced cardiovascular injury by planed-derived polyphenols and nanomaterials

Cancer therapy-induced heart injury is a significant concern for cancer patients undergoing chemotherapy, radiotherapy, immunotherapy, and also targeted molecular therapy. The use of these treatments can lead to oxidative stress and cardiomyocyte damage in the heart, which can result in heart failure and other cardiac complications. Experimental studies have revealed that chemotherapy drugs such as doxorubicin and cyclophosphamide can cause severe side effects such as cardiac fibrosis, electrophysiological remodeling, chronic oxidative stress and inflammation, etc., which may increase risk of cardiac disorders and attacks for patients that underwent chemotherapy. Similar consequences may also be observed for patients that undergo radiotherapy for left breast or lung malignancies. Polyphenols, a group of natural compounds with antioxidant and anti-inflammatory properties, have shown the potential in protecting against cancer therapy-induced heart injury. These compounds have been found to reduce oxidative stress, necrosis and apoptosis in the heart, thereby preserving cardiac function. In recent years, nanoparticles loaded with polyphenols have also provided for the delivery of these compounds and increasing their efficacy in different organs. These nanoparticles can improve the bioavailability and efficacy of polyphenols while minimizing their toxicity. This review article summarizes the current understanding of the protective effects of polyphenols and nanoparticles loaded with polyphenols against cancer therapy-induced heart injury. The article discusses the mechanisms by which polyphenols protect the heart, including antioxidant and anti-inflammation abilities. The article also highlights the potential benefits of using nanoparticles for the delivery of polyphenols.

The challenges of defining hormesis in epidemiological studies: The case of radiation hormesis

In the current radiation protection system, preventive measures and occupational exposure limits for controlling occupational exposure to ionizing radiation are based on the linear no-threshold extrapolation model. However, currently an increasing body of evidence indicates that this paradigm predicts very poorly biological responses in the low-dose exposure region. In addition, several in vitro and in vivo studies demonstrated the presence of hormetic dose response curves correlated to ionizing radiation low exposure. In this regard, it is noteworthy that also the findings of different epidemiological studies, conducted in different categories of occupationally exposed workers (e.g., healthcare, nuclear industrial and aircrew workers), observed lower rates of mortality and/or morbidity from cancer and/or other diseases in exposed workers than in unexposed ones or in the general population, then suggesting the possible occurrence of hormesis. Nevertheless, these results should be considered with caution since the identification of hormetic response in epidemiological studies is rather challenging because of a number of major limitations. In this regard, some of the most remarkable shortcomings found in epidemiological studies performed in workers exposed to ionizing radiation are represented by lack or inadequate definition of exposure doses, use of surrogates of exposure, narrow dose ranges, lack of proper control groups and poor evaluation of confounding factors. Therefore, considering the valuable role and contribution that epidemiological studies might provide to the complex risk assessment and management process, there is a clear and urgent need to overcome the aforementioned limits in order to achieve an adequate, useful and more real-life risk assessment that should also include the key concept of hormesis. Thus, in the present conceptual article we also discuss and provide possible approaches to improve the capacity of epidemiological studies to identify/define the hormetic response and consequently improve the complex process of risk assessment of ionizing radiation at low exposure doses.

Redox dysregulation in imaging professionals occupationally exposed to ionizing and non-ionizing radiation

Purpose: Imaging professionals are occupationally exposed to chronic ionizing radiation (IR) and non-ionizing radiation (NIR). This study aimed to investigate the influence of occupational radiation exposure on oxidative stress and antioxidant levels based on blood biomarkers in different hospital imaging professional groups.Materials and methods: The study groups included 66 imaging professionals occupationally exposed to IR (n = 58, 43 diagnostic radiography (G1), seven nuclear medicine (G2), eight radiation therapy (G3)), and NIR (n = 8, ultrasound imaging (G4)) and 60 non-exposed controls. Blood levels of superoxide (O2•-) as an index of oxidative stress, and the antioxidant activities of superoxide dismutase (SOD), glutathione ratio (GSH/GSSG), and catalase (CAT) were measured.Results: The blood values of O2•-, SOD, and CAT were significantly higher in imaging professionals occupationally exposed to radiation than in the control group (p < .05), while a significant decrease in the ratio of GSH/GSSG was observed (p < .05). The results from the NIR group were significantly higher compared to IR group.Conclusions: Based on these results, chronic exposure to radiation (IR and NIR) is associated with redox dysregulation that may result in damages to cellular biomolecules including lipids, proteins and DNA. Further studies are needed to determine the impact of redox dysregulation and the need for periodic examination among imaging professionals occupationally exposed to IR and NIR.

Evaluation of micronuclei and antioxidant status in hospital radiation workers occupationally exposed to low-dose ionizing radiation

PURPOSE

There is scientific evidence that ionizing radiation (IR) can be responsible for various health hazards that are one of the concerns in occupational exposure. This study was performed to evaluate DNA damage and antioxidant status in hospital workers who are occupationally exposed to low doses of IR.

MATERIALS AND METHODS

In this study, twenty occupationally exposed to low doses of IR (CT and angiography) comprising with control groups which matched them. In order to investigate the effects of chronic irradiation of radiation workers, Micronuclei (MN) frequency and the antioxidant activity of Superoxide Dismutase (SOD), Catalase (CAT) and Total Antioxidant Capacity (TAC) were measured. Then, to check adaptation against high challenge dose, the samples (in all groups) were irradiated in vitro and MN frequency was compared. Finally, to investigated the effect of the high dose after the acute and chronic low dose of ionizing radiation, MN frequency was compared in two groups (the control group that was to in-vitro irradiated (acute low dose + high dose) and radiation workers (chronic low dose + high dose)).

RESULTS

MN frequency in the occupationally exposed group (n = 30) increased significantly when compared to the control group (p-value < 0.0001). However, chronic irradiation of radiation workers could not lead to an adaptive Sresponse, while acute low-doses could produce this effect (p-value ˂ 0.05). In addition, the activity levels of antioxidant enzymes SOD, CAT, and TAC were not statistically different between the radiation workers and the control group (p-value > 0.05).

CONCLUSIONS

We observed that exposure to low doses of IR leads to increased cytogenetic damage, could not cause an adaptive-response, and improve antioxidant capacity in radiation workers. Controlling healthcare workers' exposure is the first step to improving the health of hospital workers and the quality of patient care, thus decreasing human and economic costs.

Exposure to ionizing radiations and changes in blood cells and interleukin-6 in radiation workers

Long-term exposure to ionizing radiation (IR) can cause dire health consequences even less than the dose limits. Previous biomonitoring studies have focused more on complete blood counts (CBCs), with non-coherent results. In this study, we aimed to investigate the association between exposure to IR and cytokine interleukin-6 (IL-6) along with hematological parameters in Tabriz megacity's radiation workers. In this hospital-based study, blood samples were taken from 33 radiation workers (exposed group) and 34 non-radiation workers (control group) in 4 hospitals. Absorbed radiation dose was measured by a personal film badge dosimeter in radiation workers. The studied biomarkers and all of the selected covariates were measured and analyzed using adjusted multiple linear regression models. The exposed doses for all radiation workers were under the dose limits (overall mean = 1.18 mSv/year). However, there was a significant association between exposure to ionizing radiation and IL-6 (49.78 vs 36.17; t = 2.4; p = 0.02) and eosinophils (0.17 vs 0.14; t = 2.02; p = 0.049). The difference between the mean of the other biomarkers in radiation workers was not statistically significant compared to the control group. This study demonstrated that long-term exposure to ionizing radiation, even under the dose limits, is related to a significantly increased level of some blood biomarkers (Il-6 and eosinophil) that, in turn, can cause subsequent health effects such as cancer.

Mitochondrial redox environments predict sensorimotor brain-behavior dynamics in adults with HIV

Despite virologic suppression, people living with HIV (PLWH) remain at risk for developing cognitive impairment, with aberrations in motor control being a predominant symptom leading to functional dependencies in later life. While the neuroanatomical bases of motor dysfunction have recently been illuminated, the underlying molecular processes remain poorly understood. Herein, we evaluate the predictive capacity of the mitochondrial redox environment on sensorimotor brain-behavior dynamics in 40 virally-suppressed PLWH and 40 demographically-matched controls using structural equation modeling. We used state-of-the-art approaches, including Seahorse Analyzer of mitochondrial function, electron paramagnetic resonance spectroscopy to measure superoxide levels, antioxidant activity assays and dynamic magnetoencephalographic imaging to quantify sensorimotor oscillatory dynamics. We observed differential modulation of sensorimotor brain-behavior relationships by superoxide and hydrogen peroxide-sensitive features of the redox environment in PLWH, while only superoxide-sensitive features were related to optimal oscillatory response profiles and better motor performance in controls. Moreover, these divergent pathways may be attributable to immediate, separable mechanisms of action within the redox environment seen in PLWH, as evidenced by mediation analyses. These findings suggest that mitochondrial redox parameters are important modulators of healthy and pathological oscillations in motor systems and behavior, serving as potential targets for remedying HIV-related cognitive-motor dysfunction in the future.

Assessment of thyroid gland hormones and ultrasonographic abnormalities in medical staff occupationally exposed to ionizing radiation

BACKGROUND

Ionizing radiation (IR) is high-energy radiation that has the potential to displace electrons from atoms and break chemical bonds. It has the ability to introduce mutations, DNA strand breakage, and cell death. Being a radiosensitive organ, exposure of the thyroid gland to IR can lead to significant changes in its function.

AIM OF THE WORK

Was to measure the levels of thyroid hormones panel and ultrasonography abnormalities in medical staff occupationally exposed to IR.

SUBJECTS AND METHODS

A total of 120 subjects were divided into three main groups: Group I: radiation-exposed workers occupationally exposed to radioiodine (131I) (n = 40), Group II: radiation-exposed workers occupationally exposed to X-ray (n = 40), and Group III: non-exposed healthy professionals matched in age and sex with the previous groups (n = 40). Thyroid hormones panel including free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone (TSH), anti-thyroperoxidase antibodies (anti-TPO), and thyroglobulin (Tg) were measured. Thyroid ultrasonography was performed. Oxidative stress markers such as malondialdehyde (MDA), hydrogen peroxide (H2O2), and total antioxidant capacity (TAC) were measured.

RESULTS

Group I had significantly higher fT3 levels than the control group. fT3 levels were considerably higher, while TSH was substantially lower in group II participants than in the control group. Tg was markedly lower in radiation-exposed workers. However, anti-TPO levels in radiation-exposed workers were significantly higher than in the control group. MDA and H₂O₂ were substantially higher; TAC was significantly lower in radiation-exposed workers compared to the control group. According to ultrasonographic examination, thyroid volume and the percentage of thyroid nodules in all radiation workers were significantly higher than in the control group.

CONCLUSION

Despite low exposure doses, occupational exposure to IR affects the thyroid hormones and links with a higher likelihood of developing thyroid immune diseases.

Telomere fragility in radiology workers occupationally exposed to low doses of ionising radiation

Ionising radiation damages DNA directly and indirectly through increased production of reactive oxygen species. Although telomeres have been reported as indicators of radiosensitivity, their maintenance in response to occupational exposure to low radiation doses is still a matter of debate. In this work we aimed to investigate telomere length and structure in hospital workers occupationally exposed to X-rays and to relate these findings to oxidation of biomolecules and chromosome aberrations. Blood samples of exposed participants and matching controls were taken during periodical check-ups. Chromosome aberrations and telomere length and structure were analysed in peripheral blood lymphocytes using Q-FISH, whereas oxidative stress parameters [pro/antioxidant balance (PAB), lipid peroxidation, and 8-oxo-dG] were measured in plasma samples. Based on the CA findings we divided the exposed group into two subgroups, of which one had chromosome aberrations in the first division metaphases and the other did not. There was no significant difference in telomere length between any of the groups. However, both subgroups showed significantly higher rate of fragile telomeres and higher lipid peroxidation product and 8-oxo-dG levels than controls. The rate of fragile telomeres significantly correlated with plasma levels of 8-oxo-dG, which suggests that continuous exposure to low radiation doses induces oxidative base damage of guanine resulting in telomere fragility.

Analysis of Red Blood Cells and their Components in Medical Workers with Occupational Exposure to Low-Dose Ionizing Radiation

Plenty of reports focus on the effects of low-dose radiation (LDR) on peripheral blood lymphocytes in radiation workers. However, studies on red blood cells (RBCs) in radiation workers are rarely reported. Many studies focused on investigate the hemogram of radiation staffs without detecting other components of RBCs. To explore the potential effect of LDR on RBCs, we detected the level of RBC count, hemoglobin, 2,3-disphosphoglycerate (2,3-DPG), and glutathione (GSH), and then analyzed the factors on these indices in 106 medical radiation workers. As a result, RBC count was affected by sex, age, type of work, length of service (only for females), and annual effective dose (only for males). Hemoglobin status was affected by sex, type of work, and annual effective dose (only for males). Sex, age, and type of work had no effects on the concentration of 2,3-DPG and GSH. Length of service affected 2,3-DPG concentration, and annual effective dose affected GSH level. In conclusion, chronic occupational LDR exposure may have an effect on RBC count, hemoglobin status, and the concentration of 2,3-DPG and GSH in radiation workers to some extent. However, it is still unknown how this kind of influence affects the health of radiation workers.

Superoxide dismutase and glutathione peroxidase activities in a population exposed to high indoor radon concentration: a preliminary report

The objective of this study was to assess the effect of radon exposure on the modulation of endogenous antioxidants in a population chronically exposed to high levels of radon indoors. To do so, we measured the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) in peripheral blood mononuclear cells (PBMCs) of people living in an area with high indoor radon concentration (Tande-Tande sub-village, Indonesia). The activities of SOD and GPX in Tande-Tande inhabitants were compared with those in subjects living in the Topoyo village (Indonesia), an area with low indoor radon levels. The activities of SOD and GPX in Tande-Tande sub-village inhabitants did not differ from those in people living in the Topoyo village (0.37 ± 0.021 versus 0.28 ± 0.018 U/mg protein and 8.46 ± 1.48 versus 8.34 ± 1.65 U/mg protein, p > .05). For both populations, there was a significant positive correlation between SOD and GPX activities (p < .001). No significant effects of gender, age, smoking habit, and body mass index on SOD and GPX activities were found for both groups. Although no significant modulation of SOD and GPX activities in PBMCs was detected, further studies should expand the sample size and also assess antioxidant levels in the serum. This study provides a first picture of endogenous antioxidant systems in Tande-Tande sub-village inhabitants, but a more comprehensive analysis, including the measurement of catalase (CAT) activity, might provide additional insight into the effects of chronic exposure to high indoor radon concentrations.

Neural oscillatory activity serving sensorimotor control is predicted by superoxide-sensitive mitochondrial redox environments

Mitochondrial integrity and associated redox profiles have long been revered as key contributors to a host of age- and disease-related pathologies, which eventually lead to neuronal and behavioral dysfunction in the sensorimotor and other systems. However, the precise role of the mitochondrial redox environment in human sensorimotor brain systems and motor behavior remains poorly understood. Herein, we provide evidence for a strong predictive capacity of superoxide and its scavenger, superoxide dismutase, on the neural oscillatory dynamics serving motor planning and execution above and beyond the effects of mitochondrial respiratory capacities alone. Importantly, these data provide insight regarding the impact of the redox environment on the population-level neural oscillations that serve motor function in healthy humans.

Motor control requires a coordinated ensemble of spatiotemporally precise neural oscillations across a distributed motor network, particularly in the beta range (15 to 30 Hz) to successfully plan and execute volitional actions. While substantial evidence implicates beta activity as critical to motor control, the molecular processes supporting these microcircuits and their inherent oscillatory dynamics remain poorly understood. Among these processes are mitochondrial integrity and the associated redox environments, although their direct impact on human neurophysiological function is unknown. Herein, 40 healthy adults completed a motor sequence paradigm during magnetoencephalography (MEG). MEG data were imaged in the time–frequency domain using a beamformer to evaluate beta oscillatory profiles during distinct phases of motor control (i.e., planning and execution) and subsequent behavior. To comprehensively quantify features of the mitochondrial redox environment, we used state-of-the-art systems biology approaches including Seahorse Analyzer to assess mitochondrial respiration and electron paramagnetic resonance spectroscopy to measure superoxide levels in whole blood as well as antioxidant activity assays. Using structural equation modeling, we tested the relationship between mitochondrial function and sensorimotor brain-behavior dynamics through alterations in the redox environment (e.g., generation of superoxide and alteration in antioxidant defenses). Our results indicated that superoxide-sensitive but not hydrogen peroxide–sensitive features of the redox environment had direct and mediating effects on the bioenergetic–neural pathways serving motor performance in healthy adults. Importantly, our results suggest that alterations in the redox environment may directly impact behavior above and beyond mitochondrial respiratory capacities alone and further may be effective targets for age- and disease-related declines in cognitive–motor function.

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

Hospital workers at the Oncology Department are occupationally exposed to antineoplastic drugs (ANTNP) or low doses of ionizing radiation (Irrad). Therefore, the aim of this study was to evaluate the level of DNA damage, the oxidative stress parameters and complete blood count (CBC) of hospital workers in order to analyze the negative health effects of ANTNP and low dose Irrad. The frequency of micronuclei (MN) and proliferation index (PI) were analyzed by cytokinesis-block test. The oxidative stress biomarkers evaluated were the level of lipid peroxidation in plasma and catalase activity (CAT) in erythrocytes. A group of 86 hospital workers (35 exposed to ANTPN and 51 to Irrad) had increased MN frequency, CAT activity and level of lipid peroxidation compared to the control group, which consisted of 24 volunteers. The hemoglobin level was lower in the ANTNP group compared to thecontrol group, while a significant difference in RBC was recorded between thecontrol and Irrad groups, and in platelet count betweentheIrrad and ANTNP group. The results showed increased DNA damage, oxidative stress parameters, as well as impairment on complete blood count in hospital workers occupationally exposed to antineoplastic drugs and low-dose ionizing radiation. As this research has shown the importance of oxidative stress, we suggest that in addition to routine methods in periodic medical evaluation, the possibility of applying oxidative stress parameters is considered. Moreover, hospital workers exposed to ANTNP and Irrad in the workplace should undergo not only a more complete health prevention procedure but also have a more appropriate health promotion.

Biomarkers of Atherosclerotic Vascular Disease in Workers Chronically Exposed to Ionizing Radiation

ABSTRACT

It is well established that cohorts of individuals exposed to ionizing radiation demonstrate increased risks of cardio- and cerebrovascular diseases. However, mechanisms of these radiation-induced diseases developing in individuals exposed to ionizing radiation remain unclear. To identify biomarkers of the atherosclerotic vessel damage in workers chronically exposed to ionizing radiation, this study considered 49 workers of the Russian nuclear production facility-the Mayak Production Association (mean age of 68.73 ± 6.92 years)-and 38 unexposed individuals (mean age of 68.84 ± 6.20 y) who had never been exposed to ionizing radiation (control). All workers were chronically exposed to combined radiation (external gamma rays and internal alpha particles). The mean cumulative liver absorbed dose from external gamma-ray exposure was 0.18 ± 0.12 Gy; the mean cumulative liver absorbed dose from internal alpha-particles was 0.14 ± 0.21 Gy. Levels of biomarkers in blood serum of the study participants were measured using the ELISA method. Elevated levels of apolipoprotein B, superoxide dismutase, monocyte chemoattractant protein 1, vascular cell adhesion protein 1, and a decreased level of endothelin-1 were observed in blood serum of Mayak PA workers chronically exposed to combined radiation compared to control individuals. A significant positive correlation was demonstrated between the vascular cell adhesion protein 1 level and cumulative liver absorbed doses from external gamma radiation and internal alpha radiation. Findings of the study suggest that molecular changes in blood of individuals occupationally exposed to ionizing radiation (combined internal exposure to alpha particles and external exposure to gamma rays) may indicate dyslipidemia, oxidative stress, inflammation, and endothelial dysfunction involved in atherosclerosis development.

Neuroinflammatory profiles regulated by the redox environment predicted cognitive dysfunction in people living with HIV: A cross-sectional study

BACKGROUND

Despite effective combination antiretroviral therapy (cART), people living with HIV (PLWH) remain at risk for developing neurocognitive impairment primarily due to systemic inflammation that persists despite virologic suppression, albeit the mechanisms underlying such inflammation are poorly understood.

METHODS

Herein, we evaluate the predictive capacity of the mitochondrial redox environment on circulating neuro- and T-lymphocyte-related inflammation and concomitant cognitive function in 40 virally-suppressed PLWH and 40 demographically-matched controls using structural equation modeling. We used state-of-the-art systems biology approaches including Seahorse Analyzer of mitochondrial function, electron paramagnetic resonance (EPR) spectroscopy to measure superoxide levels, antioxidant activity assays, and Meso Scale multiplex technology to quantify inflammatory proteins in the periphery.

FINDINGS

We observed disturbances in mitochondrial function and the redox environment in PLWH compared to controls, which included reduced mitochondrial capacity (t(76) = -1.85, p = 0.034, 95% CI: -∞,-0.13), elevated levels of superoxide (t(75) = 1.70, p = 0.047, 95% CI: 8.01 E 3, ∞) and alterations in antioxidant defense mechanisms (t(74) = 1.76, p = 0.041, 95% CI: -710.92, ∞). Interestingly, alterations in both superoxide- and hydrogen peroxide-sensitive redox environments were differentially predictive of neuro-, but not T-lymphocyte-related inflammatory profiles in PLWH and controls, respectively (ps < 0.026). Finally, when accounting for superoxide-sensitive redox pathways, neuroinflammatory profiles significantly predicted domain-specific cognitive function across our sample (β = -0.24, p = 0.034, 95% CI: -0.09, -0.004 for attention; β = -0.26, p = 0.018, 95% CI: -0.10, -0.01 for premorbid function).

INTERPRETATION

Our results suggest that precursors to neuroinflammation apparent in PLWH (i.e., mitochondrial function and redox environments) predict overall functionality and cognitive dysfunction and importantly, may serve as a proxy for characterizing inflammation-related functional decline in the future.

FUNDING

National Institute of Mental Health, National Institute for Neurological Disorders and Stroke, National Institute on Drug Abuse, National Science Foundation.

Low dose ionizing radiation effects on the immune system

Ionizing radiation interacts with the immune system in many ways with a multiplicity that mirrors the complexity of the immune system itself: namely the need to maintain a delicate balance between different compartments, cells and soluble factors that work collectively to protect, maintain, and restore tissue function in the face of severe challenges including radiation damage. The cytotoxic effects of high dose radiation are less relevant after low dose exposure, where subtle quantitative and functional effects predominate that may go unnoticed until late after exposure or after a second challenge reveals or exacerbates the effects. For example, low doses may permanently alter immune fitness and therefore accelerate immune senescence and pave the way for a wide spectrum of possible pathophysiological events, including early-onset of age-related degenerative disorders and cancer. By contrast, the so called low dose radiation therapy displays beneficial, anti-inflammatory and pain relieving properties in chronic inflammatory and degenerative diseases. In this review, epidemiological, clinical and experimental data regarding the effects of low-dose radiation on the homeostasis and functional integrity of immune cells will be discussed, as will be the role of immune-mediated mechanisms in the systemic manifestation of localized exposures such as inflammatory reactions. The central conclusion is that ionizing radiation fundamentally and durably reshapes the immune system. Further, the importance of discovery of immunological pathways for modifying radiation resilience amongst other research directions in this field is implied.

Low-dose ionizing radiation as a hormetin: experimental observations and therapeutic perspective for age-related disorders

Hormesis is any kind of biphasic dose-response when low doses of some agents are beneficial while higher doses are detrimental. Radiation hormesis is the most thoroughly investigated among all hormesis-like phenomena, in particular in biogerontology. In this review, we aimed to summarize research evidence supporting hormesis through exposure to low-dose ionizing radiation (LDIR). Radiation-induced longevity hormesis has been repeatedly reported in invertebrate models such as C. elegans, Drosophila and flour beetles and in vertebrate models including guinea pigs, mice and rabbits. On the contrary, suppressing natural background radiation was repeatedly found to cause detrimental effects in protozoa, bacteria and flies. We also discussed here the possibility of clinical use of LDIR, predominantly for age-related disorders, e.g., Alzheimer's disease, for which no remedies are available. There is accumulating evidence that LDIR, such as those commonly used in X-ray imaging including computer tomography, might act as a hormetin. Of course, caution should be exercised when introducing new medical practices, and LDIR therapy is no exception. However, due to the low average residual life expectancy in old patients, the short-term benefits of such interventions (e.g., potential therapeutic effect against dementia) may outweigh their hypothetical delayed risks (e.g., cancer). We argue here that assessment and clinical trials of LDIR treatments should be given priority bearing in mind the enormous economic, social and ethical implications of potentially-treatable, age-related disorders.

Exposure to Radiation During Work Shifts and Working at Night Act as Occupational Stressors Alter Redox and Inflammatory Markers

BACKGROUND

Studies of breast cancer etiology suggest evidence that night shift working and occupational exposure to ionizing radiation (IR) are defined risk factors for breast cancer development. There are few studies to clarify neuroendocrine and inflammatory status and the possible consequences particularly in occupational exposure.

AIM OF THE STUDY

Our aim was to associate the redox and inflammatory biomarkers with either nightshift working or occupational radiation exposure, and to compare their levels between the two groups at Alexandria University Hospitals, Alexandria, Egypt.

METHODS

We included 150 female nurses at Alexandria University Hospitals: 50 nightshift workers, 50 radiation workers, and 50 dayshift workers as a control group (neither work nightly nor radiation workers). In morning serum sample (7 am), we measured the concentrations of serum melatonin, Cortisol, tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) by ELISA; malondialdehyde (MDA) and total antioxidant capacity (TAC) levels colorimetrically, and C-reactive protein (C-RP) levels by turbidimetric method.

RESULTS

Nightshift workers had significantly lower levels of melatonin and TAC, and higher levels of serum inflammatory markers and cortisol, than day shift control group of workers. Workers occupationally exposed to IR had significantly higher levels of serum melatonin, MDA and inflammatory markers, lower levels of serum cortisol, and lower TAC than day shift workers.

CONCLUSION

Occupational exposure to IR and working nightly alter circulating redox and inflammatory biomarkers.

Cardiac arrhythmia catheter ablation procedures guided by x-ray imaging: N-acetylcysteine protection against radiation-induced cellular damage (CARAPACE study): study design

PURPOSE

Catheter ablation (CA) procedures are characterized by exposure to ionizing radiations (IR). IR can cause DNA damage and may lead to carcinogenesis if not efficiently repaired. The primary endpoint of this study is to investigate whether intravenous administration of N-acetylcysteine prior to CA procedure may prevent systemic oxidative stress and genomic DNA damage induced by exposure to IR.

METHODS

The "Cardiac Arrhythmia catheter ablation procedures guided by x-Ray imaging: N-Acetylcysteine Protection Against radiation induced Cellular damagE" (CARAPACE) study is a prospective, randomized, single-blinded, parallel-arm monocenter study enrolling 550 consecutive patients undergoing CA at the Arrhythmology Unit of Centro Cardiologico Monzino (CCM). Inclusion criteria are age ≥ 18, indication for CA procedure guided by IR imaging, and written informed consent. IR levels will be measured via fluoroscopy time, effective dose, and dose area product. Glutathione and glutathione disulfide concentrations will be measured, and urinary levels of 8-iso-prostaglandin-F_2α and 8-hydroxy-2-deoxyguanosine will be quantified. The enrolled patients will be randomized 1:1 to the N-acetylcysteine group or to the control group.

RESULTS

We expect that pre-operative administration of N-acetylcysteine will prevent IR-induced systemic oxidative stress. The study will provide data on oxidative DNA damage assessed by urinary 8-hydroxy-2-deoxyguanosine levels and direct evidence of genomic DNA damage in blood cells by comet assay.

CONCLUSION

Catheter ablation procedures can lead to IR exposure and subsequent DNA damage. N-acetylcysteine administration prior to the procedure may prevent them and therefore lead to less possible complications.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT04154982).

Redox Status, Dose and Antioxidant Intake in Healthcare Workers Occupationally Exposed to Ionizing Radiation

The purpose of this study was to evaluate the relationship between blood redox status, dose and antioxidant dietary intake of different hospital staff groups exposed to low doses of ionizing radiation (LDIR) (Interventional Radiology and Cardiology, Radiation Oncology, and Nuclear Medicine) and non-exposed. Personal dose equivalent (from last year and cumulative), plasma antioxidant markers (total antioxidant capacity, extracellular superoxide dismutase activity, and glutathione/oxidized glutathione ratio), oxidative stress markers (nitrites and nitrates, and lipid peroxidation) and dietary intake (antioxidant capacity using ORAC values) were collected and analyzed from 28 non-exposed healthcare workers and 42 healthcare workers exposed to LDIR. Hospital staff exposed to LDIR presented a redox imbalance in blood that seems to correlate with dose. Workers from the Nuclear Medicine Unit were the most affected group with the lowest value of plasma antioxidant response and the highest value of plasma thiobarbituric acid reactive substances, TBARS (indicator of lipid peroxidation) of all four groups. Cumulative personal dose equivalent positively correlated with nitrites and negatively correlated with total antioxidant capacity in blood. The diet of healthcare workers from Nuclear Medicine Unit had higher ORAC values than the diet of non-exposed. Therefore, occupational exposure to LDIR, especially for the Nuclear Medicine Unit, seems to produce an imbalanced redox status in blood that would correlate with cumulative personal dose equivalent.

Oxidative Stress in Pregnant Women Between 12 and 20 Weeks of Gestation and Preterm Birth

BACKGROUND

A known relationship exists between oxidative stress and preterm birth (PTB). However, few studies have measured oxidative stress prospectively in early or midpregnancy, and no studies have used electron paramagnetic resonance (EPR) spectroscopy prospectively to predict PTB.

OBJECTIVE

The purpose of this study was to identify predictive relationships between antioxidants and reactive oxygen species (ROS), specifically, superoxide (O2), peroxynitrite (OONO), and hydroxyl radical (OH), using EPR spectroscopy, measured between 12 and 20 weeks of gestation and compare with the incidence of PTB.

METHODS

Blood was obtained from pregnant women (n = 140) recruited from a tertiary perinatal center. Whole blood was analyzed directly for ROS, O2, OONO, and OH using EPR spectroscopy. Red blood cell lysate was used to measure antioxidants. PTB was defined as parturition at <37 weeks of gestation.

RESULTS

No differences were found between ROS, O2, OONO, or OH with the incidence of PTB. Catalase activity, glutathione, and reduced/oxidized glutathione ratio were significantly lower with PTB. Logistic regression suggests decreased catalase activity in pregnant women is associated with increased odds of delivering prematurely.

DISCUSSION

We prospectively compared antioxidants and specific ROS using EPR spectroscopy in pregnant women between 12 and 20 weeks of gestation with the incidence of PTB. Results are minimal but do suggest that antioxidants-specifically decreased catalase activity-in early pregnancy may be associated with PTB; however, these findings should be cautiously interpreted and may not have clinical significance.

Oxidative stress in early pregnancy and the risk of preeclampsia

INTRODUCTION

Preeclampsia (PE), one of the most serious complications of pregnancy, is characterized by endothelial dysfunction and hypertension. The pathophysiology of the disease is still unknown; however, evidence suggests that placental and maternal oxidative stress promote the disease process. Several studies have assessed levels of oxidative stress during pregnancy, but after diagnosis of PE. However, few studies have examined oxidative stress before PE diagnosis. Thus, the present work was aimed to gain further insight into the role of oxidative stress prior to diagnosis of PE (i.e. 12-20 weeks of gestation) and to further understand and predict PE incidence.

METHODS

Blood levels of superoxide (O₂^-) and erythrocyte antioxidants such as superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and oxidized glutathione (GSSG) levels were measured in 23 preeclamptic pregnant women and 91 women with normal pregnancies. We further used logistic regression of O₂^- and each antioxidant level as the main predictor variable for PE risk.

RESULTS

CAT activity, GSH, and Total glutathione (TGSH) were significantly lower with All PE pregnant groups, whereas O₂^- levels were modestly, but significantly, higher in women with mild PE. Logistic regression analysis suggests increased CAT activity in pregnant women is associated with a decreased odds of being preeclamptic.

CONCLUSION

CAT is the only antioxidant as shown in our study to be related to the severity of the disease and may be a promising predictor for PE. Further studies are warranted to investigate the use of CAT as a novel therapeutic for PE.

Manifestations of allostatic load in residents of radiation contaminated areas aged 18–24 years

We studied the features of allostatic load (AL) in 100 students aged 18–24 years old who, from birth to adulthood, lived in the territories assigned to the IV radiation zone after the Chornobyl accident (density of soil contamination by isotopes 137Cs 3.7–18.5∙104 Bq/m2) and underwent prolonged exposure to small doses of ionizing radiation. The examined students did not have any clinical signs of the immune-neuroendocrine system dysfunction. 50 people had signs of vegetative-vascular dystonia syndrome (VVD), 48 had signs of moderate hyperthyroidism and 21 had signs of moderate hypothyroidism. During the examination session, as a factor of additional psycho-emotional load, in 66 of the examined the immunoregulatory index CD4+/CD8+ went below the lower limit of the homeostatic norm, in 62 of the examined low density lipoprotein cholesterol (LDL-C) exceeded the upper level. The relative risk (RR) and attributable risk (AR) of the participation of potential secondary factors of allostatic load formation in CD4+/CD8+ immunoregulatory index going below the lower limit were calculated. The presence of statistically significant relative risk of participation in the formation of suppression of the index CD4+/CD8+: the state of hyperthyroidism, state of hypothyroidism, vegetative-vascular dystonia syndrome, higher than normal LDL-C. When the examined students combined the signs of hyperthyroidism, vegetative-vascular dystonia syndrome and higher level of LDL-C; with combination of signs of hypothyroidism, vegetative-vascular dystonia syndrome and higher level of LDL-C. The attributable risk in all cases exceeded 0.10, which confirmed the importance of some of these factors and their complexes in the formation of the effect of reduced immunoregulatory index. The CD4+/CD8+ index can be considered an important biomarker of AL and premature age-related changes in the immune system in residents of radiation-contaminated areas. The risk of AL formation in the case of occurrence of a complex of mediated secondary biomarkers (vegetative-vascular dystonia syndrome, thyroid dysfunction, hypercholesterolemia) is higher compared to their individual significance.

Oxidative Stress Levels Throughout Pregnancy, at Birth, and in the Neonate

BACKGROUND

Oxidative stress is associated with poor perinatal outcomes. Little is known regarding the longitudinal levels of oxidative stress in the perinatal period or the correlation between maternal and neonatal oxidative stress levels.

OBJECTIVE

Describe and compare oxidative stress, specifically superoxide, superoxide dismutase, catalase, and glutathione levels, over the perinatal period.

STUDY DESIGN

Longitudinal descriptive design using a convenience sample of medically high- and low-risk pregnant women (n = 140) from a maternal-fetal medicine and general obstetrics practice, respectively. Blood was obtained from women at 12-20 and 24-28 weeks' gestation and during labor, from the umbilical cord at birth, and from neonates at 24-72 hr after birth. Levels of superoxide were measured using electron paramagnetic resonance (EPR) spectroscopy; antioxidants (superoxide dismutase, catalase, and glutathione) were measured using commercial assay kits. Relationships between oxidative stress levels at different time points were examined using nonparametric methods. Pregnancy outcome was collected.

RESULTS

Demographic variables, outcome variables, and oxidative stress levels in maternal blood, cord blood, and infants differed between medically high- and low-risk women. Descriptive patterns for oxidative stress measures varied over time and between risk groups. Significant correlations between time points were noted, suggesting intraindividual consistency may exist throughout the perinatal period. However, these correlations were not consistent across each medical risk group.

CONCLUSION

EPR spectroscopy is a feasible method for the perinatal population. Results provide new information on perinatal circulating superoxide levels and warrant further investigation into potential relationships between prenatal and neonatal physiologic dysregulation of oxidative stress.

Healthcare Workers Occupationally Exposed to Ionizing Radiation Exhibit Altered Levels of Inflammatory Cytokines and Redox Parameters

Studies have shown an increased risk for a variety of cancers, specifically brain cancer, in healthcare workers occupationally exposed to ionizing radiation. Although the mechanisms mediating these phenomena are not fully understood, ionizing radiation-mediated elevated levels of reactive oxygen species (ROS), oxidative DNA damage, and immune modulation are likely involved. A group of 20 radiation exposed workers and 40 sex- and age-matched non-exposed control subjects were recruited for the study. We measured superoxide (O₂•⁻) levels in whole blood of healthcare workers and all other measurements of cytokines, oxidative DNA damage, extracellular superoxide dismutase (EcSOD) activity and reduced/oxidized glutathione ratio (GSH/GSSG) in plasma. Levels of O₂•⁻ were significantly higher in radiation exposed workers compared to control. Similarly, a significant increase in the levels of interleukin (IL)-6, IL-1α and macrophage inflammatory protein (MIP)-1α in radiation exposed workers compared to control was observed, while there was no significance difference in the other 27 screened cytokines. A significant positive correlation was found between MIP-1α and O₂•⁻ levels with no correlation in either IL-6 or IL-1α. Further, a dose-dependent relationship with significant O₂•⁻ production and immune alterations in radiation exposed workers was demonstrated. There was no statistical difference between the groups in terms of oxidative DNA damage, GSH/GSSG levels, or EcSOD activity. Although the biologic significance of cytokines alterations in radiation exposed workers is unclear, further studies are needed for determining the underlying mechanism of their elevation.

Does Fluoroscopy Induce DNA Oxidative Damage in Patients Undergoing Catheter Ablation?

As no studies before now have thoroughly investigated the risk associated with the exposure to low-dose ionizing radiations in patients undergoing catheter ablation (CA), we aimed to evaluate the oxidative and DNA damage in 59 CA patients (10 of whom received N-acetylcysteine (NAC) before the procedure). A burst of oxidized/reduced glutathione ratio was observed 3 hours after procedure that was diminished by NAC administration. 8-Hydroxy-2'-deoxyguanosine (8-OHdG) concentrations, index of oxidative DNA damage, showed a peak 24 hours after CA. A positive correlation between 8-OHdG peak and fluoroscopy time and a negative correlation among 8-OHdG decrease (from the peak to 48 hours after CA) and all procedure parameters were found. Furthermore, DNA tail percentages (which reflect the extent and the number of DNA strand breaks) positively correlated with 8-OHdG concentrations. This study evaluates for the first time the kinetic of oxidative damage in patients undergoing CA procedure. Our findings raise the question of whether 8-OHdG can be used as a circulating biomarker of DNA oxidative damage induced by low-dose ionizing radiations in different clinical settings. Antioxid. Redox Signal. 28, 1137-1143.

Health Effects from Occupational Radiation Exposure among Fluoroscopy-Guided Interventional Medical Workers: A Systematic Review

A systematic review was conducted to provide an overview of the health effects of occupational radiation exposure from interventional fluoroscopy procedures on medical radiation workers. Among the 34 studies that met the inclusion criteria, most studies were cross-sectional (76%) and published after 2011 (65%) in a handful of countries. Although diverse outcomes were reported, most studies focused on cataracts. Radiation health effects were rarely assessed by risk per unit dose. Interventional radiation medical workers represent a small subset of the population studied worldwide. Further epidemiologic studies should be conducted to evaluate health outcomes among interventional radiation medical workers.

Psychosocial work environment and oxidative stress among nurses'

Background:

Work stress among nurses has increased in recent years due to the demands of clinical nursing.

Objectives:

To investigate psychosocial work stress among nurses using the effort-reward imbalance (ERI) model with assessment malondialdehyde (MDA) as an oxidative stress marker and total antioxidants.

Methods:

The present study was conducted on 204 registered nurses worked at two tertiary hospitals in Menoufia governorate, Egypt through the period from the 1st of February to the end of July 2016. Two questionnaires were applied including general demographic and occupational histories as well as effort-reward questionnaire. Blood analysis was performed to assess MDA and total antioxidant levels.

Results:

ERI was prevalent among the study participants (72.5%). ERI was more prevalent among young married nurses who worked more than 10 years. Nurses that worked at ICUs complained more of ERI (43.2%) while nurses that worked at operation rooms complained more of overcommitment (62.5%). MDA levels were significantly positively correlated with E/R ratios (rho = 0.350, P ≤ 0.001).

Conclusions:

Work stress was prevalent among the studied nurses as revealed by the high ERI and MDA levels. Young married female nurses complained more of work stress. ICUs and operating rooms were the most stressful departments at the studied hospitals. Hence, implementing programs and strategies that eliminate stressful working conditions at hospitals is critical to the reduction and prevention of work stress among nurses.