Low Levels Of Oxidative Stress Research Articles

Oxidative stress in the retina and retinal pigment epithelium (RPE): Role of aging, and DJ-1

High levels of oxidative radicals generated by daily light exposure and high metabolic rate suggest that the antioxidant machinery of the retina and retinal pigment epithelium (RPE) is crucial for their survival. DJ-1 is a redox-sensitive protein that has been shown to have neuroprotective function in the brain in Parkinson's disease and other neurodegenerative diseases. Here, we analyzed the role of DJ-1 in the retina during oxidative stress and aging. We induced low-level oxidative stress in young (3-month-old) and old (15-month-old) C57BL/6J (WT) and DJ-1 knockout (KO) mice and evaluated effects in the RPE and retina. Absence of DJ-1 resulted in increased retinal dysfunction in response to low levels of oxidative stress. Our findings suggest that loss of DJ-1 affects the RPE antioxidant machinery, rendering it unable to combat and neutralize low-level oxidative stress, irrespective of age. Moreover, they draw a parallel to the retinal degeneration observed in AMD, where the occurrence of genetic variants may leave the retina and RPE unable to fight sustained, low-levels of oxidative stress.

Mitochondria-Associated Degradation Pathway (MAD) Function beyond the Outer Membrane

SUMMARYThe mitochondria-associated degradation pathway (MAD) mediates ubiquitination and degradation of mitochondrial outer membrane (MOM) proteins by the proteasome. We find that the MAD, but not other quality-control pathways including macroautophagy, mitophagy, or mitochondrial chaperones and proteases, is critical for yeast cellular fitness under conditions of paraquat (PQ)-induced oxidative stress in mitochondria. Specifically, inhibition of the MAD increases PQ-induced defects in growth and mitochondrial quality and decreases chronological lifespan. We use mass spectrometry analysis to identify possible MAD substrates as mitochondrial proteins that exhibit increased ubiquitination in response to PQ treatment and inhibition of the MAD. We identify candidate substrates in the mitochondrial matrix and inner membrane and confirm that two matrix proteins are MAD substrates. Our studies reveal a broader function for the MAD in mitochondrial protein surveillance beyond the MOM and a major role for the MAD in cellular and mitochondrial fitness in response to chronic, low-level oxidative stress in mitochondria.

Electrolyte, Nitric Oxide and Oxidative Stress Levels of Aqueous Humor in Patients with Retinal Detachment and Silicone Oil Tamponade

ABSTRACT Purpose: To enlighten the pathogenesis of silicone oil (SiO)-related complications via measuring aqueous humor levels of electrolytes, nitric oxide (NO), and oxidative stress in SiO, retinal detachment (RD), and control groups. Materials and Methods: In this prospective study, 56 patients were grouped as SiO (n = 29), RD (n = 12), and control (n = 15). The results of pre- and post-operative ophthalmological examinations, aqueous humor electrolyte and NO levels, total antioxidant and oxidant status (TAS, TOS) and oxidative stress index (OSI) were analyzed. Results: SiO group had a higher mean Na+ level compared to controls (144.77 ± 11.48 vs 137.56 ± 6.57 mmol/kg, p = .02). Also, the mean Na+ and Cl− levels of RD group were higher than controls (149.04 ± 12.05 vs. 137.56 ± 6.57 mmol/kg, p = .02, 115.2 ± 7.79 vs 106.23 ± 8.99 mmol/kg, p = .031 for Na+ and Cl−, respectively). The mean NO level of RD group was higher than that of SiO group (51.07 ± 19.56 vs. 34.07 ± 13.84 μM, p = .009). The mean TAS and TOS were lower in SiO group compared to controls (1.92 ± 0.64 vs. 2.49 ± 0.56 μmolTroloxEqv./L, p = .021, 34.98 ± 26.55 vs. 61.46 ± 22.69 μmolH2O2Eqv./L, p = .004 for TAS and TOS, respectively). Intraocular retention time of SiO demonstrated positive correlation with post-operative visual acuity (logMAR) and negative correlation with TOS. Conclusions: Elevated aqueous humor Na+ and Cl− in RD patients might reflect abolished function of ion channels on detached retina. Increased Na+ and lack of NO response to elevated intraocular pressure in SiO-filled eyes might contribute to secondary cataract and glaucoma formation. SiO is associated with low levels of oxidative stress in aqueous humor; however, increased intraocular retention time of SiO is related to a poor visual outcome.

Cellular Uptake, Stability, and Safety of Hollow Carbon Sphere-Protected Fe₃O₄ Nanoparticles.

Magnetic iron oxide (Fe₃O₄) nanoparticles (NPs) have attracted extensive attentions in biomedical fields such as magnetic resonance imaging (MRI). However, the instability and unfavorable dispersity of bare Fe₃O₄ NPs is a challenge for biomedical applications. Herein, we proposed a strategy using hollow carbon sphere (HCS) as a shell structure to endow Fe₃O₄ NPs better stability, dispersity, as well as biocompatibility. To verify intracellular behaviors and biosafety of HCSdecorated Fe₃O₄ nanoparticles (Fe₃O₄@HCS NPs), the assessment of cellular effects of these NPs based on synchrotron radiation-based techniques were done to explore detailed interaction between Fe₃O₄@HCS NPs and liver cells, HepG2. We found that a large number of NPs were internalized by cells in a time-dependent manner determined by inductively coupled plasma mass spectrometry (ICP-MS), which was further supported by intracellular accumulation of iron via X-ray fluorescence (XRF) imaging. Moreover, confocal imaging showed that these NPs mainly located in the lysosomes where they remained stable and undissolved within 72 hours, which was verified by chemical form characterization of iron via Fe K-edge X-ray adsorption near edge structure (XANES). With the coating shell of HCS, the release of iron ions was prevented even in acidic lysosome and the integrity of lysosomal membrane remained unchanged during the storage of NPs. As a result, Fe₃O₄@HCS NPs exhibited low level of oxidative stress and induced negligible cytotoxicity towards HepG2 cells. Based on the powerful techniques, we demonstrated that the carbon outer layer provides a physical barrier that helps remain excellent properties of magnetic Fe₃O₄ NPs and good dispersity, chemical stability, as well as biocompatibility for potential applications in biomedical fields.

Effect of exogenous additives on oxidative stress and defense system of a tree: Zanthoxylum armatum DC. under in vitro conditions

Toxicity related to oxidative stress has been a concern for mature, woody tree species with high phenolic content when placed under in vitro conditions, particularly at explant establishment stage. The study of biochemical factors responsible for oxidative stress (lipid peroxidation, reactive oxygen species like hydrogen peroxide) and the defense (antioxidant enzymes and non-enzymatic factors) that the plant offers, in the tree system under in vitro environment requires special consideration. This study focuses on the effect of exogenous additives [polyvinyl pyrrolidone (PVP), citric acid (CC), ascorbic acid (AA)] and initial dark treatment on oxidative stress, defense system, DNA oxidation, total chlorophyll content for the in vitro explant establishment of a medicinal tree Zanthoxylum armatum DC., for a duration of 1-month. Exogenous additives and darkness maintained a sustained level of lipid peroxidation hydrogen peroxide, oxidized DNA content and antioxidant enzymes (superoxide dismutase, catalase, and ascorbate peroxidase) in the modified treatment throughout the in vitro experimental period, in comparison to the control. Thus, establishing a relation between exogenous antioxidants and explant oxidative stress-free condition. This can further be utilized to prevent oxidative leaching of explant of mature and woody trees in vitro. Explants of Z. armatum were able to survive under in vitro conditions for 1 month, with low levels of phenolic leaching and oxidative stress, when additives (2 g L−1 PVP, 100 mg L−1 CC, 100 mg L−1 AA) are added in the medium with initial dark treatment for 72 h.

Genotypic variation for cadmium tolerance in common bean (Phaseolus vulgaris L.).

Given the limitation of crop production in Cd-polluted areas, the identification and selection of plant genotypes tolerant to Cd stress are of great significance. In the present work, we show the existence of genotypic variation for Cd tolerance in common bean. The laboratory screening of 25 bean genotypes indicated a significant positive correlation of the mean productivity (MP) and the geometric mean productivity (GMP) with plant fresh weight both in control and Cd-treated plants. A principal component analysis further confirmed this variation and, together with other analyses, led to the selection of genotypes G-11867, Taylor, Emerson, and D-81083 as tolerant genotypes. A total of six bean genotypes with different degrees of Cd tolerance were selected, and their long-term physiological responses to Cd (0, 45, and 90mg/kg soil) were evaluated. Increasing Cd concentrations led to higher Cd accumulation both in roots and shoots, and to significant rises in the levels of the oxidative stress biomarkers malondialdehyde (MDA), dityrosine (D-T), and 8-hydroxy-2'-deoxyguanosine (8-OH-2'-dG). Remarkable reductions in plant hormone levels and chlorophyll contents, as well as in dry and fresh weight, were observed in Cd-treated plants. Among the examined genotypes, Emerson, Taylor, and G-11867 were found to be more tolerant to Cd owing to lower Cd accumulation and lower oxidative stress levels, as well as higher chlorophyll and hormone contents. Our results contribute to the understanding of the physiological and biochemical basis of Cd tolerance in bean plants and may therefore, be useful for breeding programs directed towards obtaining bean varieties showing low Cd accumulation.

Effect of defined, seasonally variable exercise on oxidative status markers (TOS, TAS) in jumping horses

The present study aimed to determine the adaptation capacity of horses subjected to defined, seasonally variable exercise on the basis of selected indicators of their oxidative status. The research was carried out over a two-year period on 25 Polish Noble Half-bred horses (PKSP). All horses came from stables in south-eastern Poland (51°15’00”N, 22°34’00”E) and competed in show jumping. According to the intensity of exercise, two experimental periods were distinguished, characterized by moderate intensity of exercise (D1) and high intensity of exercise (D2). The test material consisted of blood taken from the external jugular vein into dry tubes in a closed system. Samples were collected four times. The oxidative status was determined by means of PerOx reagents (TOS/TOC) and ImAnOx reagents (TAS/TAC) from Immundiagnostik. The results were analyzed statistically with the Statistica 10 software (StatSoft Inc.). Changes were found in all parameters studied. The average level of total antioxidant status (TAS) in our research was low, and the average level of total oxidant status (TOS) obtained in the experiment corresponds to a low level of oxidative stress. The oxidant status and the antioxidant status did not correlate with each other. The values were balanced regardless of sex or age, which suggests that training did not result in oxidative stress. Our results also suggest that evaluation of blood oxidative markers can help in assessing the welfare of training horses.

Donepezil: A review of the recent structural modifications and their impact on anti-Alzheimer activity

Alzheimer disease (AD) is characterized by a low level of acetylcholine, beta-amyloid (Aβ) aggregation and oxidative stress. Donepezil is the core medicine used for the treatment of AD. Various structural modifications of donepezil have been carried out. Benzylpiperidine part of donepezil has been replaced with benzylpyridine, pyridyl methylpiperidine, benzylpiperazine, pyrimidyl piperazine. These derived molecules showed promising activities as anti-Alzheimer agents. Replacement of indanone part by other heterocyclic rings such as pyridine resulted in the formation of compounds which exhibited monoamine oxidase (MAO) as well as acetylcholinesterase (AChE) inhibition. Propargylamine containing derivatives displayed AChE as well as MAO inhibition properties. Attachment of donepezil with natural compounds like ferulic acid, flavonoids, and curcumin showed antioxidant activities in addition to inhibition of the AChE. Benzylpiperidine and benzylpiperazine have also been combined with condensed heterocyclic rings and these compounds displayed promising anti-Alzheimer properties. This review highlights the important structural modifications of donepezil and their influence on biological activities as anti-Alzheimer agents.

70 Trolox during invitro maturation of bovine oocytes protects developing embryos from palmitic acid-induced lipotoxicity

Maternal metabolic disorders are associated with elevated concentrations of palmitic acid (PA), which is known to jeopardize bovine oocyte and embryo development and quality. Analyses of PA-exposed bovine oocytes and embryos point toward oxidative stress (OS)-related pathways. Previous research has shown that the detrimental effects of PA exposure during oocyte IVM cannot be alleviated by antioxidant supplementation, e.g. Trolox (TR, water-soluble vitamin E), during IVM or invitro culture (IVC). In contrast, supplementing TR during IVM could protect developing zygotes from PA-induced lipotoxicity by increasing their development into 4-cell embryos and Day 8 blastocysts. In the present study, we examined the effects of TR during IVM or IVC on PA-exposed oocytes and embryos by evaluating OS and mitochondrial membrane potential (MMP) of the produced ≥2-cell Day 2 embryos (Table 1). Bovine cumulus-oocyte complexes (COCs) were matured, fertilised, and cultured in 2 experiments. In Experiment 1, COCs were exposed to pathophysiological follicular PA concentrations (150 µM), and subsequent embryos were cultured under solvent control (ethanol) conditions (PA-SC). The TR treatment was applied during IVM or IVC (100 µM; PATR-SC, PA-TR). In Experiment 2, COCs were matured under SC conditions, and subsequent embryos were exposed to pathophysiological oviductal PA concentrations (230 µM; SC-PA). The TR treatment was applied during IVM or IVC (100 µM; TR-PA, SC-PATR). In each experiment, a SC was included (SC-SC). A total of 126 and 137 Day 2 embryos were stained with JC-1 and CellRox Deep Red in Experiment 1 and Experiment 2 (3 repeats), respectively. The MMP was evaluated as active/total mitochondria and OS as OS/total mitochondria and analysed by one-way ANOVA. Exposure of oocytes and embryos to PA significantly increased OS and MMP in Day 2 embryos compared with controls. Regardless of the moment of PA exposure, TR treatment during IVM increased MMP even more. The increased MMP levels in PA-exposed oocytes and embryos were not influenced by TR treatment during IVC. Regardless of the antioxidant effect of TR, increased embryonic OS levels observed in PA-exposed oocytes and embryos could not be reversed to control levels by TR treatment during IVM or IVC. However, when OS levels were expressed on active mitochondria, we found that TR treatment before the PA insult (TR-PA) generated Day 2 embryos that displayed significantly lower OS/active mitochondria rates compared with SC-PA-treated embryos. Taken together, we conclude that the combination of relatively low OS levels with highly active mitochondria may be a mechanism implicated in the protective effect of TR before the PA insult on embryo developmental competence. Table 1.Effects of TR during IVM or IVC on PA-exposed oocytes and embryos in Experiments 1 and 2 Controls PA exposure TR during IVM TR during IVC SC-SC PA-SC PATR-SC PA-TR Exp. 1 MMP 0.39±0.02a 0.53±0.02b 0.65±0.02c 0.50±0.02b OS 0.55±0.04a 0.68±0.04b 0.78±0.03b 0.59±0.03ab SC-SC SC-PA TR-PA SC-PATR Exp. 2 MMP 0.39±0.02a 0.50±0.02b 0.65±0.02c 0.58±0.02b OS 0.55±0.04a 0.69±0.04b 0.70±0.03b 0.71±0.02b abcDifferent letters in the same row indicate significant differences (P<0.05).

Nanosized silver, but not titanium dioxide or zinc oxide, enhances oxidative stress and inflammatory response by inducing 5-HETE activation in THP-1 cells

Bioactive, oxygenated metabolites of polyunsaturated fatty acids (PUFAs) are important indicators of inflammation and oxidative stress but almost nothing is known about their interactions with nanomaterials (NMs). To investigate the effects of nano-sized materials (n-TiO2, n-ZnO, n-Ag) and their bulk-sized or ionic (b-TiO2, b-ZnO, i-Ag) counterpart, we studied the status of oxidative stress and PUFA metabolism in THP-1 cells at low-toxic concentrations (<15% cytotoxicity) 6 h or 24 h after the particle exposures by LC/MS and microarray. N-Ag had a significant and sustained impact on cellular antioxidant defense, seen as incremental synthesis and accumulation of glutathione (GSH) in the cell, and reduction of superoxide dismutase (SOD) activity. The cellular particle doses were largely dependent on exposure duration and particle dissolution, and active transporter mechanisms controlled the concentration of Zn in cytosol. Even at these sub-toxic concentrations, n-Ag was able to induce statistically significant elevation in the 5-HETE: arachidonic acid ratio at 24 h, which suggests association to oxidative stress and induction of pro-inflammatory responses. This was supported by the enhanced gene expression of chemotaxis-related genes. Overall, THP-1 cells internalized all tested particles, but only n-Ag led to low level of oxidative stress through ROS production and antioxidant balance disruption. N-Ag stimulated arachidonic acid oxidation to form 5-HETE which further magnified the inflammatory responses by enhancing the production of mitochondrial superoxide and leukocyte chemokines. Since the sustained n-Ag uptake was detected, the effects may last long and function as a trigger for the low-grade inflammation playing role in the chronic inflammatory diseases.

A proteome-wide assessment of the oxidative stress paradigm for metal and metal-oxide nanomaterials in human macrophages

Responsible implementation of engineered nanomaterials (ENMs) into commercial applications is an important societal issue, driving demand for new approaches for rapid and comprehensive evaluation of their bioactivity and safety. An essential part of any research focused on identifying potential hazards of ENMs is the appropriate selection of biological endpoints to evaluate. Herein, we use a tiered strategy employing both targeted biological assays and untargeted quantitative proteomics to elucidate the biological responses of human THP-1 derived macrophages across a library of metal/metal oxide ENMs, raised as priority ENMs for investigation by NIEHS's Nanomaterial Health Implications Research (NHIR) program. Our results show that quantitative cellular proteome profiles readily distinguish ENM types based on their cytotoxic potential according to induction of biological processes and pathways involved in the cellular antioxidant response, TCA cycle, oxidative stress, endoplasmic reticulum stress, and immune responses as major processes impacted. Interestingly, bioinformatics analysis of differentially expressed proteins also revealed new biological processes that were influenced by all ENMs independent of their cytotoxic potential. These included biological processes that were previously implicated as mechanisms cells employ as adaptive responses to low levels of oxidative stress, including cell adhesion, protein translation and protein targeting. Unsupervised clustering revealed the most striking proteome changes that differentiated ENM classes highlight a small subset of proteins involved in the oxidative stress response (HMOX1), protein chaperone functions (HS71B, DNJB1), and autophagy (SQSTM), providing a potential new panel of markers of ENM-induced cellular stress. To our knowledge, the results represent the most comprehensive profiling of the biological responses to a library of ENMs conducted using quantitative mass spectrometry-based proteomics. The results provide a basis to identify the patterns of a diverse set of cellular pathways and biological processes impacted by ENM exposure in an important immune cell type, laying the foundation for multivariate, pathway-level structure activity assessments of ENMs in the future.

Neuroprotective Effects of Serpina3k in Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of disability and mortality worldwide, in part resulting from secondary apoptosis of neurons in peri-contusion areas. Serpina3k, a serine protease inhibitor, has been shown to inhibit apoptosis in injury models. In this study, we investigated the anti-apoptotic function of serpina3k in vivo using a mouse model of TBI, as well as the underlying neuroprotective mechanism in vitro using the SH-SY5Y human neuroblastoma cell line. TBI was induced in adult male C57BL/6 mice using controlled cortical impact. Serpina3k protein was intravenously administered at a concentration of 0.5 mg/kg twice daily for up to 14 days. SH-SY5Y cells were subjected to biaxial stretch injury and then treated with different concentrations of serpina3k. We found that endogenous serpina3k protein levels were elevated in peri-contusion areas of the mouse brain following TBI. Serpina3k-treated mice had fewer apoptotic neurons, lower levels of oxidative stress, and showed greater recovery of neurological deficits relative to vehicle-treated mice. Meanwhile, in the SH-SY5Y cell injury model, serpina3k at an optimal concentration (150 nM) inhibited the generation of intracellular reactive oxygen species, abrogated changes of the mitochondrial membrane potential, and reduced the phospho-extracellular regulated protein kinases (p-ERK)/ERK, phospho-P38 (p-P38)/P38, B cell lymphoma (Bcl)-2-associated X protein/Bcl-2, and cleaved caspase-3/caspase-3 ratios, thereby reducing the apoptosis rate. These results demonstrate that serpina3k exerts a neuroprotective function following TBI and thus has therapeutic potential.

Effect of transcutaneous electrical acupoint stimulation on protecting against radiotherapy- induced ovarian damage in mice

BackgroundPremature ovarian insufficiency (POI) is characterized by early loss of ovarian function that affects women before the age of 40. We aim to explore the protective effects of transcutaneous electrical acupoint stimulation (TEAS) against irradiation-induced ovarian damage in mice.MethodsC57BL6 mice were randomly divided into control and irradiation (IR) groups. Then, control group was divided into two treatment subgroups: mock TEAS treatment (control-) and TEAS treatment (control+). IR group was divided into four subgroups according to the time of treatment started: mock TEAS treatment initiated at 2 days after irradiation (IR 2D-), TEAS treatment initiated at 2 days after irradiation (IR 2D+), mock TEAS treatment initiated at 1 week after irradiation (IR 1 W-), and TEAS treatment initiated at 1 week after irradiation (IR 1 W+). The radiation model mice were exposed to single whole body X-ray irradiation (4 Gy), and the control mice received 0 Gy. TEAS stimulation (2 Hz, 1 mA, 30 min/day) was given once a day for six consecutive days per week for 2 weeks. Estrous cycle, ovarian weight, serum AMH level and follicle counts were evaluated. Then, proliferation markers, apoptotic markers and oxidative stress markers were examined.ResultsCompared with the control group, the estrous cycle was disordered, and the ovarian weight, serum AMH, and primordial, primary and secondary follicles counts decreased (all P < 0.01) in the IR 2D- and IR 1 W- groups. In the irradiation with early TEAS treatment group (IR 2D+), the estrous cycle improved, the AMH level and primordial follicular significantly increased compared to the irradiation with mock group (IR 2D-). However, there were no significant differences in the estrous cycle, AMH level and follicle counts between IR 1 W- and IR 1 W+ groups. Moreover, IR 2D+ mice reduced the expression of Bax protein and increased the levels of Bcl-2 and PCNA compared to the IR 2D- group. Furthermore, the early TEAS treated mice showed significantly lower levels of oxidative stress and number of TUNEL (+) granulosa cells than that in the IR 2D- group.ConclusionThis study is first to evaluate TEAS as a potential therapy to attenuate irradiation-induced ovarian failure through inhibiting primordial follicles loss, increasing serum AMH secretion, inducing antioxidant, and anti-apoptotic systems.

Hypothermic oxygenated machine perfusion alleviates liver injury in donation after circulatory death through activating autophagy in mice.

Hypothermic oxygenated machine perfusion (HOPE) is a safe and reliable method that could alleviate liver injury in donation after circulatory death (DCD). This study focuses on the role of autophagy in HOPE's protective effect on DCD liver injury. A 30-minute warm ischemic liver model was established in mice. After 4 hours of cold storage (CS), 1 hour of hypothermic machine perfusion (HMP) with 100% O2 or 100% N2 was employed. During 2 hours of reperfusion, liver tissue and perfusate were collected to evaluate liver function, oxidative stress level, apoptosis, and necrosis. Western blotting was used to explore the level of autophagy. When the liver experienced warm ischemic injury, LC3B-II expression was significantly enhanced. Compared with the CS, HOPE induced lower release of AST and ALT, as well as lower oxidative stress levels, apoptosis, and necrosis cell numbers, and led to higher tissue ATP content. Meanwhile, expression of autophagy-related proteins, such as ULK1, Atg5, and LC3B-II, increased. When oxygen was completely replaced by nitrogen, the washout effect of HMP did not activate autophagy and did not relieve DCD liver injury. When the autophagy inhibitor 3-methyladenine was used in HOPE, the protective effect of HOPE was attenuated. In conclusion, DCD liver injury activated autophagy compared with healthy liver, while HOPE alleviated DCD liver injury by increasing autophagy levels further in this mouse model. However, HMP with 100% of N2 had no beneficial effect on DCD liver injury or on autophagy levels compared with CS. The research on autophagy may provide a new strategy for alleviating DCD liver injury in clinical practice.

Mitochondria Associated Degradation Pathway (MAD) Function Beyond the Outer Membrane

The mitochondria-associated degradation (MAD) pathway mediates ubiquitination and removal of mitochondrial outer membrane (MOM) proteins, and targets them for degradation by the proteasome. We find that MAD, but not other mitochondrial control pathways including macroautophagy, mitophagy, or mitochondrial chaperones and proteases, is critical for yeast cellular fitness under conditions of paraquat (PQ) induced chronic, low-level oxidative stress in mitochondria. Specifically, inhibition of MAD results in increased PQ-induced defects in growth and mitochondrial quality, and reduced chronological lifespan. In light of this, we tested whether MAD function in mitochondrial proteostasis extends beyond the known substrates in MOM. Our mass spectrometry analysis revealed possible MAD substrates in different mitochondrial compartments. We confirmed that 2 matrix proteins, Kgd1p and Pim1p, are MAD substrates. Our studies reveal a broader function for MAD in mitochondrial protein surveillance beyond the MOM, and a major role in cellular and mitochondrial fitness in response to chronic, low level oxidative stress in mitochondria.

The response of five intestinal cell lines to anoxic conditions in vitro

In vivo oxygen levels in tissues range from 1% to 15%, while mechanistic cell culture studies employ an atmospheric oxygen level of 21% to grow cells. These oxygen concentrations are therefore not representative for conditions where the cell response is dependent on oxygen partial pressure. In pathological situation, such as (colon) cancer or chronic inflammation, tissue oxygenation is severely affected, and even under physiological conditions a steep oxygen gradient is present in the large intestine, where epithelial cells co-exist with microbial species, resulting in almost anoxia at the midpoint of the lumen. In these situations, a better characterisation of the essential cellular behaviour under hypoxia or anoxia is required. We have characterised the cellular response of commonly used cell cultures for the study of intestinal epithelial processes and colon cancer development (Caco-2, HT-29, SW480, HCT 116 and LoVo) under conventional normoxic conditions (21% O2 ) and in an anoxic (<0.1% O2 ) environment generated in an anaerobic chamber. In general, anoxic conditions led to lower levels of oxidative stress, a reduction in reduced glutathione/oxidised glutathione (GSH/GSSG) ratio, the shift of the redox status to oxidised glutathione levels, reduced cell proliferation, decreased barrier function and higher glycolysis rates at the expense of oxidative respiration. Continuous exposure to anoxic conditions, such as occurring at the host-microbe interface in the intestine, may create an adaptive metabolic cellular response of the cells. Considering adequate oxygen levels is essential for creating more physiologically relevant models for the study of host-microbe interactions and colon cancer development.

Contribution of sociodemographic, occupational, lifestyle and dietary characteristics to the oxidative stress microenvironment in adipose tissue

The present study was conceived on the basis of the few previous reports suggesting a potential relevance of the oxidative stress microenvironment in the adipose tissue, a biological matrix which is closely related to the development of several chronic pathologies. Thus, our aim was to describe the levels of enzymatic and non-enzymatic antioxidants and markers of oxidative damage in adipose tissue samples from a Spanish cohort, as well as their main sociodemographic, lifestyle, and dietary predictors.The study was conducted in a subsample (n = 271 adults) of GraMo cohort, recruited in Granada (Southern Spain). A face-to-face questionnaire was used to gather data regarding sociodemographic characteristics, lifestyle, dietary habits, health status, and perceived exposure to chemicals. We analyzed adipose tissue levels of lipid peroxidation (TBARS), total superoxide dismutase (SOD) activity, heme oxygenase-1 (HO-1) activity, and glutathione cycle biomarkers. Potential predictors of oxidative stress markers were assessed using stepwise multivariable linear regression analyses.SOD and TBARS levels were mainly related to sociodemographic and occupational characteristics, while the components of the glutathione cycle and HO-1 were predominantly associated with dietary habits. Men showed significantly lower levels of oxidative stress levels than women. In the regression models including only women, the use of oral contraceptive and hormonal therapy was associated with lower levels of oxidative stress, while the number of children was positively associated with increased oxidative biomarkers.Our results suggest that adipose tissue is potentially important matrix for the assessment of oxidative stress, which can be affected by specific environmental factors. These findings might be relevant for public health.

Effects of Losartan on Oxidative Stress, DNA Damage, and Metabolic Parameters in Whole Blood and Liver of Rhesus Monkeys (Macaca mulatta)

Angiotensin II (Ang II), the primary peptide of the Renin Angiotensin System (RAS), can induce the production of reactive oxygen species (ROS) and affect mitochondrial energetics, predisposing to age‐related disorders. Angiotensin converting enzyme inhibitors (ACE) and angiotensin receptor blockers (ARB) can attenuate ROS production, improve mitochondrial function and increase survival in aging rodents, however, the effects of losartan, an ARB, on age‐associated oxidative damage in rhesus monkeys have not been yet explored. We have previously shown that mitochondrial DNA (mtDNA) damage, depletion of mtDNA molecules and oxidative stress increase in liver and blood leukocytes of middle‐age and old rhesus monkeys. We hypothesize that losartan treatment prevents oxidative damage in liver and blood leukocytes from rhesus monkeys. To test our hypothesis we examined the effects of losartan on mtDNA, nuclear DNA (nDNA) and protein damage, mtDNA abundance in whole blood and liver and metabolic parameters in losartan‐treated and age‐matched untreated middle‐age rhesus monkeys. Middle‐age rhesus monkeys (8–19 years of age) were treated with losartan (30mg/day) for 12 months and samples were obtained at baseline, 3, 6, and 12 months after treatment. Young (3–6 years of age) untreated monkeys were also analyzed as a control for the effects of aging. Fasting insulin and fasting glucose were measured in the serum and mitochondrial DNA (mtDNA) damage and abundance, and nuclear DNA (nDNA) damage were assessed by quantitative PCR. Protein carbonylations were measured in peripheral blood mononuclear cells (PBMCs) and liver of rhesus monkeys using the FTC Fluorometric assay. Interestingly, we found that losartan significantly decreased fasting blood glucose levels in healthy middle‐age monkeys after 12 months of treatment when compared to age‐matched untreated animals. No effects were observed on systolic/diastolic blood pressure, fasting insulin, cholesterol, tryglycerides and glycated hemoglobin levels. In whole blood samples, middle‐age monkeys exhibit significant increased levels of nDNA lesions compared to young animals, and treatment with losartan decreased nDNA damage to levels similar to young animals. Moreover, we found a significant decrease in the levels of carbonylated proteins in PBMCs from middle‐age monkeys treated with losartan compared to untreated monkeys, indicative of lower levels of oxidative stress. No significant differences were observed in the levels of mtDNA copies between the groups. In liver, middle‐age monkeys exhibited decreased levels of mtDNA molecules and losartan had no effect on preventing the loss of mtDNA copies. In contrast to PBMCs, no significant differences were observed in nDNA lesions and protein carbonylations between groups. Surprisingly, losartan significantly increased the levels of mtDNA damage as compared to young animals. Collectively, our results suggest that losartan precludes nDNA (but not mtDNA) and protein oxidative damage in PBMCs (but not in liver) and improves glucose levels in healthy middle‐age rhesus monkeys.Support or Funding InformationP40RR003640R25 GM061838U54 MD007600This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

SARCOPENIA, SARCOPENIC OBESITY AND FRAILTY; LINKS TO COGNITIVE PERFORMANCE IN ELDERS: Session 412

Background: According to 2011 CDC data, more than 2.6 million adults aged 60 and older with cognitive impairment reported difficulty performing one or more ADLs. There are studies that link cognitive decline and physical impairment in terms of low-level chronic inflammation, oxidative stress, and depression. Skeletal muscle can produce IL-1, IL-6 and other important myokines that have been implicated in cognitive and physical functional degenerative processes. Oxidative stressors have been linked to physical frailty and sarcopenia as well as neurodegenerative processes further worsening cognitive impairment. What are Sarcopenia and Sarcopenic Obesity and its impacts on elders? Sarcopenia is a primary disease of the elderly population, characterized by loss of skeletal muscle mass and function. Sarcopenia is correlated with physical disability, poor quality of life, frailty, cognitive impairment, and death. Age, gender, and level of physical activity are the risk factors for the Sarcopenia. In addition to aging, malignancy and rheumatoid arthritis causes loss of lean body mass and even increase in body fat mass. The loss of muscle mass associated with increased body fat mass i.e. sarcopenic obesity causes weakness in aging. Sarcopenia, with or without obesity, results in impairment of IADL (Instrumental Activity of Daily Living) and eventually ADLs (Activities of Daily Living) among elders and results in need for long-term care and increased cost of health care. What is the link between Sarcopenia and Cognitive Impairment? Sarcopenia has not only has a greater effect on survival but also on cognitive impairment. Sarcopenia has been linked to global cognitive impairment and dysfunction in specific cognitive skills including memory, speed, and executive functions. While obesity may impair the executive functions of aging, the exact mechanism linking obesity to cognitive dysfunction is not clear. Improvement in muscular function of obese older adults has been linked to improvement of executive functions. Obesity and Sarcopenia were associated with the lower executive function such as working memory, mental flexibility, self-control and orientation when assessed independently and even more so when they occurred together. Sarcopenia is highly correlated with frailty and risk of falls in elders; it also represents an important risk factor for disability and mortality. Frailty is an independent predictor of dementia. How do you assess for the Sarcopenia? Sarcopenia with or without obesity can be used in clinical practice to assess the potential risk of cognitive impairment in elders. There are several ways to measure Sarcopenia – DEXA (Dual-Energy X-ray Absorptiometry), biometric impedance analysis (BIA), CT (Computed Tomography) scan and MRI (Magnetic Resonance Imaging). However, assessing BMI and testing grip strength by dynamometry can be easily administered during annual wellness visits to assess the risk of sarcopenic related cognitive impairments. Sarcopenia can be assessed using parameters such as 1) Measure walking speed in elderly (>65 years). If the walking speed is below 0.8 m/s at the 4-m walking test, measure the muscle mass. 2) Hand- grip strength if this value is lower than 20kg in women and 30kg in man then muscle mass must be analyzed. 3) Defining Fat mass and lean body mass using BIA 4) Muscle Mass assessment by DEXA or CT. What is the significance of assessing the Sarcopenia? It is important to identify the risk of cognitive impairment by assessing for the onset of this condition. Preventing or delaying onset will likely enhance survival and reduce the demand for long-term care. Increasing resistance physical training will help to improve physical deconditioning, strengthen skeletal muscle hypertrophy, overcome the pain syndrome and enhance overall mental well-being. Interventions such as resistance exercise and nutritional therapy need to be developed specifically to delay the onset of Sarcopenia. What is the need in the future? Team-based approach including multidisciplinary model involving primary care physicians, geriatric psychiatrists, pain management physicians and physical therapists is required to combat the complex interlinked Sarcopenia associated cognitive impairment. Screening programs that include identification of cognitive and functional impairment in the office setting will serve as the starting point for specific interventions. The training regimen that includes supervision and correct equipment with resistance exercise will be necessary to get proper training and delay the muscle loss in elderly.

The Effects of Swimming Training in Cold Water on Antioxidant Enzyme Activity and Lipid Peroxidation in Erythrocytes of Male and Female Aged Rats.

The aim of this study was to verify whether eight-week-long swimming exercise training would evaluate the level of selected indicators of the pro-oxidant/antioxidant status in response to cold water in comparison with swimming under thermoneutral conditions in sedentary male and female elderly rats. The exercise-trained groups swam four min/day and five days a week during eight weeks of housing. Exercise was performed by swimming in glass tanks containing tap water maintained according to group at 5 °C and 36 °C. At the end of treatment (48 h after the last session), all rats were anaesthetized. The level of chosen biomarkers of oxidative stress and antioxidant enzyme activity was determined in the red blood cells and plasma. The results of study show that female rats seem to be better adapted to changing thermal conditions of the environment, developing not only morphological, but also antioxidant, defense mechanisms, mainly in the form of increased erythrocyte superoxide dismutase (SOD) activity and glutathione (GSH) concentration to restore the pro-oxidant/oxidant balance of the organism. Significantly higher concentrations of GSH were observed in the female rats of the group swimming in cold water (by 15.4% compared to the control group and by 20.5% in relation to the group of female rats swimming at 36 °C). In the group exposed to swimming training exercise in cold water, a significantly higher activity of SOD1 (by 13.4%) was found compared to the control group. On the other hand, the organs of ageing male rats show a reduced capacity to increase the metabolic response to low temperatures compared to female ones. In addition, it was demonstrated that cold exposure leads to an increase in lipid peroxidation in tissues. On the other hand, the repeated exposure to low levels of oxidative stress may result in some adaptive changes in organisms that help them to resist stress-induced damage.