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

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.

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.

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.

Estrogen-induced disruption of intracellular iron metabolism leads to oxidative stress, membrane damage, and cell cycle arrest in MCF-7 cells.

It is well established that several forms of cancer associate with significant iron overload. Recent studies have suggested that estrogen (E2) disrupts intracellular iron homeostasis by reducing hepcidin synthesis and maintaining ferroportin integrity. Here, the ability of E2 to alter intracellular iron status and cell growth potential was investigated in MCF-7 cells treated with increasing concentrations of E2. Treated cells were assessed for intracellular iron status, the expression of key proteins involved in iron metabolism, oxidative stress, cell survival, growth, and apoptosis. E2 treatment resulted in a significant reduction in hepcidin expression and a significant increase in hypoxia-inducible factor 1 alpha, ferroportin, transferrin receptor, and ferritin expression; a transient decrease in labile iron pool; and a significant increase in total intracellular iron content mainly at 20 nM/48 h E2 dose. Treated cells also showed increased total glutathione and oxidized glutathione levels, increased superoxide dismutase activity, and increased hemoxygenase 1 expression. Treatment with E2 at 20 nM for 48 h resulted in a significant reduction in cell growth (0.35/1 migration rate) and decreased cell survival (<80%) as compared with controls. Survivin expression significantly increased at 24 h post treatment with 5, 10, or 20 nM; however, that of γ-H2AX increased only after survivin levels dropped and only at the 20 nM E2 dose. Minimal upregulation and splitting of caspase 9 was only evident in cells treated with 20 nM E2; no changes in caspase 3 expression were evident. Although Annexin V staining studies showed that E2 treatment did not induce apoptosis, scanning electron microscopy studies showed marked membrane blebbing at 20 nM/48 h of E2. These findings suggest that estrogen treatment disrupts intracellular iron metabolism and precipitates adverse effects concerning cell viability, membrane integrity, and growth potential.

Nanoformulated copper/zinc superoxide dismutase attenuates vascular cell activation and aortic inflammation in obesity.

OBJECTIVE: Endothelial cell (EC) oxidative stress can lead to vascular dysfunction which is an underlying event in the development of cardiovascular disease (CVD). The lack of a potent and bioavailable anti-oxidant enzyme is a major challenge in studies on antioxidant therapy. The objective of this study is to determine whether copper/zinc superoxide dismutase (CuZnSOD or SOD1) after nanoformulation (nanoSOD) can effectively reduce EC oxidative stress and/or vascular inflammation in obesity. METHODS: Human aortic endothelial cells (HAECs) were treated with native- or nanoSOD for 6 h followed by treatment with linoleic acid (LA), a free fatty acid, for 6-24 h. To determine the in vivo relevance, the effectiveness of nanoSOD in reducing vascular cell activation was studied in a mouse model of diet-induced obesity. RESULTS: We noted that nanoSOD was more effectively taken up by ECs than native SOD. Western blot analysis further confirmed that the intracellular accumulation of SOD1 protein was greatly increased upon nanoSOD treatment. Importantly, nanoSOD pretreatment led to a significant decrease in LA-induced oxidative stress in ECs which was associated with a marked increase in SOD enzyme activity in ECs. In vivo studies showed a significant decrease in markers of EC/vascular cell activation and/or inflammation in visceral adipose tissue (VAT), thoracic aorta, and heart collected from nanoSOD-treated mice compared to obese control mice. Interestingly, the expression of metallothionein 2, an antioxidant gene was significantly increased in nanoSOD-treated mice. CONCLUSION: Our data show that nanoSOD is very effective in delivering active SOD to ECs and in reducing EC oxidative stress. Our data also demonstrate that nanoSOD will be a useful tool to reduce vascular cell activation in VAT and aorta in obesity which, in turn, can protect against obesity-associated CVD, in particular, hypertension.

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.

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.

Heme Oxygenase-1 Inhibition Modulates Autophagy and Augments Arsenic Trioxide Cytotoxicity in Pancreatic Cancer Cells.

Pancreatic ductal adenocarcinoma (PDAC) is the most prevalent form, accounting for more than 90% of all pancreatic malignancies. In a previous study, we found that hypoxia and chemotherapy induced expression of Heme Oxygenase-1 (HO-1) in PDAC cells and tissues. Arsenic trioxide (ATO) is the first-line chemotherapeutic drug for acute promyelocytic leukemia (APL). ATO increases the generation of reactive oxidative species (ROS) and induces apoptosis in treated cells. The clinical use of ATO for solid tumors is limited due to severe systemic toxicity. In order to reduce cytotoxic side effects and resistance and improve efficacy, it has become increasingly common to use combination therapies to treat cancers. In this study, we used ATO-sensitive and less sensitive PDAC cell lines to test the effect of combining HO-1 inhibitors (SnPP and ZnPP) with ATO on HO-1 expression, cell survival, and other parameters. Our results show that ATO significantly induced the expression of HO-1 in different PDAC cells through the p38 MAPK signaling pathway. ROS production was confirmed using the oxygen-sensitive probes DCFH and DHE, N-acetyl cysteine (NAC), an ROS scavenger, and oxidized glutathione levels (GSSG). Both ATO and HO-1 inhibitors reduced PDAC cell survival. In combined treatment, inhibiting HO-1 significantly increased ATO cytotoxicity, disrupted the GSH cycle, and induced apoptosis as measured using flow cytometry. ATO and HO-1 inhibition modulated autophagy as shown by increased expression of autophagy markers ATG5, p62, and LC3B in PDAC cells. This increase was attenuated by NAC treatment, indicating that autophagy modulation was through an ROS-dependent mechanism. In conclusion, our work explored new strategies that could lead to the development of less toxic and more effective therapies against PDAC by combining increased cellular stress and targeting autophagy.

Oxidation of thiols and modification of redox-sensitive signaling in human lung epithelial cells exposed to Pseudomonas pyocyanin.

The aim of this study was to examine the effects of pyocyanin exposure on mitochondrial GSH, other cellular thiols (thioredoxin-1, Trx-1), and oxidant-sensitive signaling pathways hypoxia inducible factor (HIF-1α) and heme oxygenase (HO-1) in A549 and HBE cell lines. A549 human type II alveolar epithelial cells and human bronchial epithelial (HBE) cells were treated with varying concentrations of pyocyanin extracted from Pseudomonas aeruginosa bacteria. Cytoplasmic and mitochondrial thiols and oxidant sensitive signal transduction proteins (HIF-1α and HO-1) were measured. Exposure to pyocyanin generated reactive oxygen species (ROS) in cellular mitochondria and altered total cellular glutathione (GSH). Pyocyanin, at concentrations present in conditions in vivo, increased oxidized Trx-1 in A549 human type II alveolar epithelial cells and HBE cells by 184 and 74%, respectively. Oxidized mitochondrial glutathione (GSSG) was elevated more than twofold in both cell types. Pyocyanin also increased the cellular oxidant-sensitive proteins HIF-1α and HO-1. Data indicate that pyocyanin-induced alterations in mitochondrial and cytosolic thiols, as well as oxidant-sensitive proteins, may contribute to P. aeruginosa-mediated lung injury.

Increased oxidative stress and iron overload in Jordanian ß-thalassemic children.

ß-Thalassemia (ß-thal) is associated with abnormal synthesis of hemoglobin (Hb). Repeated blood transfusions in patients with ß-thal major (ß-TM) leads to an enhanced generation of reactive oxygen species (ROS), and subjects patients to peroxidative injury. We studied the antioxidant status and oxidative damage to children with ß-thal in Jordan. Samples from 40 children with ß-thal and 40 healthy controls were used. All children were under 13 years of age. Our results showed that plasma thiobarbituric acid reactive substances (TBARS) were elevated in ß-thalassemic children compared to controls together with compensatory increase in superoxide dismutase (SOD) activity and decrease in catalase (CAT) activity. Elevated serum ferritin showed positive correlation with elevated liver enzyme levels except gamma glutamyl transferase (GGT), confirming liver involvement due to iron overload. Serum ferritin also showed a positive correlation with elevated TBARS and SOD, suggesting that iron overload is involved in the oxidative stress shown in cells.

Heme Oxygenase-1 Inhibition Potentiates the Effects of Nab-Paclitaxel-Gemcitabine and Modulates the Tumor Microenvironment in Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a poor prognosis. Tumor hypoxia plays an active role in promoting tumor progression, malignancy, and resistance to therapy in PDAC. We present evidence that nab-paclitaxel-gemcitabine (NPG) and/or a hypoxic tumor microenvironment (TME) up-regulate heme oxygenase-1 (HO-1), providing a survival advantage for tumors. Using PDAC cells in vitro and a PDAC mouse model, we found that NPG chemotherapy up-regulated expression of HO-1 in PDAC cells and increased its nuclear translocation. Inhibition of HO-1 with ZnPP and SnPP sensitized PDAC cells to NPG-induced cytotoxicity (p < 0.05) and increased apoptosis (p < 0.05). Additionally, HO-1 expression was increased in gemcitabine-resistant PDAC cells (p < 0.05), and HO-1 inhibition increased GEM-resistant PDAC sensitivity to NPG (p < 0.05). NPG combined with HO-1 inhibitor inhibited tumor size in an orthotopic model. In parallel, HO-1 inhibition abrogated the influx of macrophages and FoxP3+ cells, while increasing the proportion of CD8+ infiltration in the pancreatic tumors. These effects were mediated primarily by reducing expression of the immunosuppressive cytokine IL-10.

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 (ß = -0.24, p = 0.034, 95% CI: -0.09, -0.004 for attention; ß = -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.

Increased levels of superoxide and H2O2 mediate the differential susceptibility of cancer cells versus normal cells to glucose deprivation.

Cancer cells, relative to normal cells, demonstrate increased sensitivity to glucose-deprivation-induced cytotoxicity. To determine whether oxidative stress mediated by O(2)(*-) and hydroperoxides contributed to the differential susceptibility of human epithelial cancer cells to glucose deprivation, the oxidation of DHE (dihydroethidine; for O(2)(*-)) and CDCFH(2) [5- (and 6-)carboxy-2',7'-dichlorodihydrofluorescein diacetate; for hydroperoxides] was measured in human colon and breast cancer cells (HT29, HCT116, SW480 and MB231) and compared with that in normal human cells [FHC cells, 33Co cells and HMECs (human mammary epithelial cells)]. Cancer cells showed significant increases in DHE (2-20-fold) and CDCFH(2) (1.8-10-fold) oxidation, relative to normal cells, that were more pronounced in the presence of the mitochondrial electron-transport-chain blocker, antimycin A. Furthermore, HCT116 and MB231 cells were more susceptible to glucose-deprivation-induced cytotoxicity and oxidative stress, relative to 33Co cells and HMECs. HT29 cells were also more susceptible to 2DG (2-deoxyglucose)-induced cytotoxicity, relative to FHC cells. Overexpression of manganese SOD (superoxide dismutase) and mitochondrially targeted catalase significantly protected HCT116 and MB231 cells from glucose-deprivation-induced cytotoxicity and oxidative stress and also protected HT29 cells from 2DG-induced cytotoxicity. These results show that cancer cells (relative to normal cells) demonstrate increased steady-state levels of ROS (reactive oxygen species; i.e. O(2)(*-) and H(2)O(2)) that contribute to differential susceptibility to glucose-deprivation-induced cytotoxicity and oxidative stress. These studies support the hypotheses that cancer cells increase glucose metabolism to compensate for excess metabolic production of ROS and that inhibition of glucose and hydroperoxide metabolism may provide a biochemical target for selectively enhancing cytotoxicity and oxidative stress in human cancer cells.

2-Deoxy-D-glucose combined with cisplatin enhances cytotoxicity via metabolic oxidative stress in human head and neck cancer cells.

Glucose deprivation has been hypothesized to cause cytotoxicity by inducing metabolic oxidative stress in human cancer cells. The current work tests the hypothesis that 2-deoxy-d-glucose (2DG) combined with cisplatin [cis-diamminedichloroplatinum(II)] can enhance cytotoxicity in human head and neck cancer cells (FaDu) by mechanisms involving oxidative stress. Exposure of FaDu cells to the combination of 2DG and cisplatin resulted in a significant decrease in cell survival when compared with 2DG or cisplatin alone. Treatment with 2DG and cisplatin also caused perturbations in parameters indicative of oxidative stress, including decreased intracellular total glutathione and increased percentage of glutathione disulfide. Simultaneous treatment with the thiol antioxidant N-acetylcysteine (NAC) inhibited parameters indicative of oxidative stress, as well as protected FaDu cells from the cytotoxic effects of cisplatin alone and the combination of 2DG and cisplatin. In addition, polyethylene glycol-conjugated antioxidant enzymes (PEG-superoxide dismutase and PEG-catalase) also protected FaDu cells from 2DG toxicity. An inhibitor of glutathione synthesis, l-buthionine-[S,R]-sulfoximine (BSO), sensitized FaDu cells to the cytotoxic effects of 2DG and cisplatin, and these effects were inhibited by NAC. Furthermore, the combination of 2DG, cisplatin, and BSO significantly increased the percentage of glutathione disulfide, which was also inhibited by NAC. These results support the hypothesis that exposure of human head and neck cancer cells to 2DG combined with cisplatin enhances cytotoxicity via metabolic oxidative stress. These findings provide a strong biochemical rationale for evaluating inhibitors of glucose and hydroperoxide metabolism in combination with cisplatin for the treatment of head and neck cancer.

Reply to "Comment on Ahmad, I.M. et al. Healthcare Workers Occupationally Exposed to Ionizing Radiation Exhibit Altered Levels of Inflammatory Cytokines and Redox Parameters. Antioxidants, 2019, 8, 12".

Bevelacqua and Mortazavi [...].

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.

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.

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.

Enhancing responsiveness of pancreatic cancer cells to gemcitabine treatment under hypoxia by heme oxygenase-1 inhibition.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies and has one of the worst prognoses leading to a meager 5-year survival rate of ∼8%. Chemotherapy has had limited success in extending the life span of patients with advanced PDAC due to poor tumor perfusion and hypoxia-induced resistance. Hypoxia reprograms the gene expression profile and upregulates the expression of multiple genes including heme oxygenase-1 (HO-1), which provide survival advantage to PDAC cells. However, the relationships between HO-1, hypoxia, and response to chemotherapy is unclear. Our results showed that hypoxia upregulates the expression of HO-1 in PDAC cells, and HO-1 inhibition using the HO-1 inhibitors zinc protoporphyrin, tin protoporphyrin IX (SnPP), and HO-1 knockout using CRISPR/Cas9 suppresses the proliferation of PDAC cells under hypoxia and sensitize them to gemcitabine under in vitro conditions. Treating orthotopic tumors with SnPP, or SnPP in combination with gemcitabine, significantly reduced the weight of pancreatic tumors (P < 0.05), decreased metastasis and improved the efficacy of gemcitabine treatment (P < 0.05). Mechanistically, inhibition of HO-1 increased the production of reactive oxygen species as demonstrated by increased dihydroethidium, and Mitosox, disrupted glutathione cycle, and enhanced apoptosis. There was significant increase in cleaved caspase-3 staining in tumors after combined treatment with SnPP and gemcitabine comparing to control or gemcitabine alone. In addition, inhibiting HO-1 reduced expression of stemness markers (CD133, and CD44) as compared to control or gemcitabine. Overall, our study may present a novel therapeutic regimen that might be adopted for the treatment of PDAC patients.

2-Deoxyglucose combined with wild-type p53 overexpression enhances cytotoxicity in human prostate cancer cells via oxidative stress.

Overexpression of the tumor suppressor gene, wild-type p53 (wtp53), using adenoviral vectors (Adp53) has been suggested to kill cancer cells by hydroperoxide-mediated oxidative stress [1,2] and nutrient distress induced by the glucose analog, 2-deoxyglucose (2DG), has been suggested to enhance tumor cell killing by agents that induce oxidative stress via disrupting hydroperoxide metabolism [3,4]. In the current study clonogenic cell killing of PC-3 and DU-145 human prostate cancer cells (lacking functional p53) mediated by 4 h exposure to 50 plaque forming units (pfus)/cell of Adp53 (that caused the enforced overexpression of wtp53) was significantly enhanced by treatment with 2DG. Accumulation of glutathione disulfide was found to be significantly greater in both cell lines treated with 2DG+Adp53 and both cell lines treated with 2DG+Adp53 showed a approximately 2-fold increases in dihydroethidine (DHE) and 5-(and-6)-carboxy-2',7'-dichlorodihydrofluorescein diacetate (CDCFH(2)) oxidation, indicative of increased steady-state levels of O(2)(.-) and hydroperoxides, respectively. Finally, overexpression of catalase or glutathione peroxidase using adenoviral vectors partially, but significantly, protected DU-145 cells from the toxicity induced by 2DG+Adp53 treatment. These results show that treatment of human prostate cancer cells with the combination of 2DG (a nutrient stress) and overexpression of the tumor suppressor gene, wtp53, enhances clonogenic cell killing by a mechanism that involves oxidative stress as well as allowing for the speculation that inhibitors of glucose and hydroperoxide metabolism can be used in combination with Adp53 gene therapy to enhance therapeutic responses.