Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a marker of oxidative stress in rheumatoid arthritis and aging: effect of progressive resistance training

Rituximab alleviates increased disomic sperm in DBA/1J mouse models of rheumatoid arthritis via restoration of redox imbalance

Compared to the general population, patients with arthritis have a higher risk of fertility abnormalities, which have deleterious effects on both reproductive function and pregnancy outcomes, especially in patients wishing to conceive. These may be due to the disease itself or those of drug therapies. Despite the increasing use of rituximab in arthritis, limited data are available on its potential to induce aneuploidy in germ cells. Therefore, the aim of the current investigation was to determine if repeated treatment with rituximab affects the incidence of aneuploidy and redox imbalance in arthritic mouse sperm. Mice were treated with 250 mg/kg rituximab once weakly for 3 weeks, and then sperm were sampled 22 days after the last dose of rituximab. Fluorescence in situ hybridization assay with chromosome-specific DNA probes was used to evaluate the disomic/diploid sperm. Our results showed that rituximab had no aneuploidogenic effect on the meiotic stage of spermatogenesis. Conversely, arthritis induced a significantly high frequency of disomy, and treatment of arthritic mice with rituximab reduced the increased levels of disomic sperm. The occurrence of total diploidy was not significantly different in all groups. Reduced glutathione and8-hydroxydeoxyguanosine, markers of oxidative stress were significantly altered in arthritic animals, while rituximab treatment restored these changes. Additionally, arthritis severity was reduced after rituximab treatment. We conclude that rituximab may efficiently alleviate the arthritis-induced effects on male meiosis and avert the higher risk of abnormal reproductive outcomes. Therefore, treating arthritic patients with rituximab may efficiently inhibit the transmission of genetic anomalies induced by arthritis to future generations.

Aneugenic and clastogenic alterations in the DBA/IJ mouse model of rheumatoid arthritis treated with rituximab, an anti-CD20 antibody

Rheumatoid arthritis (RA), an autoimmune disorder in which the immune system attacks healthy cells, is associated with elevated risk of lymphoma. Rituximab, a treatment for non-Hodgkin's lymphoma, has been approved as a treatment for RA. We studied the effects of rituximab on chromosomal stability in collagen-induced arthritis DBA/1J animal models. Micronucleus levels were increased in the mouse models, mainly due to chromosome loss, as detected by fluorescence in situ hybridization; rituximab-treated arthritic mice had significantly less micronucleus formation. Serum 8-hydroxydeoxyguanosine, a DNA oxidative stress marker, was increased in the mice models but reduced following rituximab administration.

Non-Invasive Measurement of Exercise-Induced Oxidative Stress in Response to Physical Activity. A Systematic Review and Meta-Analysis

Physical activity may benefit health by modulating oxidative stress and inflammation. However, the selection of suitable exercise-induced oxidative stress biomarkers is still challenging. This study aimed at systematically summarizing the available evidence on exercise-induced oxidative stress measured in urine and/or saliva. Two meta-analyses including the most frequently quantified biomarkers of oxidative stress, namely, urinary isoprostane and DNA oxidation products, were performed. Three electronic databases (PubMed, EMBASE and Cochrane CENTRAL) were interrogated. Among 4479 records, 43 original articles were included in the systematic review and 11 articles were included in meta-analysis I and II, respectively. We observed a pooled trend of increase of urinary isoprostanes in response to physical activity (+0.95, 95% CI: -0.18; 2.09). In comparison with aerobic exercise, anaerobic training determined a greater induction of isoprostanes (+5.21, 95% CI: 2.76; 7.66, p < 0.0001), which were markedly increased after vigorous physical activity (+6.01, 95% CI: 1.18; 10.84, p < 0.001) and slightly decreased in response to exercise interventions protracted over time (e.g., months) (-1.19, 95% CI: -2.25; -0.12, p < 0.001). We recommend the most integrative approach of oxidative stress multi-marker panels in response to physical activity instead of selecting one preferential biomarker to quantify physical activity-induced oxidative stress in humans.

Diurnal relationship between core clock gene BMAL1, antioxidant SOD1 and oxidative RNA/DNA damage in young and older healthy women

BACKGROUND AND OBJECTIVES

BMAL1 is a core clock gene that positively regulates circadian rhythms. In animals, BMAL1 further acts as transcription factor for the SOD1 gene which encodes the major antioxidant enzyme superoxide dismutase. SOD1 protects against oxidative damage that is a major factor for human aging. Mice lacking mBmal1 exhibit premature aging phenotypes which might be related to a reduced expression of SOD1. The purpose of this study was to explore the circadian relationship between BMAL1, SOD1, oxidative RNA/DNA damage and aging in healthy humans.

SUBJECTS AND METHODS

In a cross-sectional study design, buccal mucosa cells and saliva samples were obtained from 21 young (23.7 ± 2.3 yrs) and 21 older women (66.8 ± 5.7 yrs) within 24 h at 4-h intervals (08:00, 12:00, 16:00, 20:00, 24:00 and 04:00 h). Transcript levels of BMAL1 and SOD1 were measured by real-time quantitative PCR. Protein levels of SOD1 were determined by immunoblotting and densitometry. Levels of oxidative RNA/DNA damage and melatonin were quantified by enzyme immunosorbent assays.

RESULTS

Transcript levels of BMAL1 and SOD1 mRNAs as well as protein levels of SOD1 and melatonin exhibited significant 24-h variation in each age group (P < 0.010, Friedman tests). The mRNA expression patterns of BMAL1 and SOD1 showed similar 24-h rhythmicity and positive relationships were found. Strongest relationships occurred in young women at 12:00 h (rs = 0.81, P = 0.005) and in older women at 08:00 h (r = 0.84, P < 0.001). Maximum levels of SOD1 mRNA appeared within 24 h in both age groups at 24:00 h. In both age groups, the timing of maximum level for SOD1 protein was delayed relative to the timing of maximum level for SOD1 mRNA. This delay was larger in older women (8 h) compared to young women (4 h). Older women showed higher oxidative RNA/DNA damage at all time-points compared to young women (P < 0.020). The oxidative RNA/DNA damage decreased continuously from 08:00 to 20:00 h (P < 0.001) in both age groups. Although oxidative damage and SOD1 protein levels declined simultaneously, only weak and non-significant relationships were noted.

CONCLUSIONS

This study demonstrates that transcript levels of SOD1 and protein level of SOD1 follow a circadian pattern of expression in healthy young and older women. The time-shift found between the 24-h maximum levels of SOD1 mRNA and SOD1 protein could be explained by the time needed for translation of SOD1 protein. The positive relationship found between expression levels of SOD1 mRNA and BMAL1 mRNA is in line with animal studies showing that BMAL1 acts as transcription factor and regulates the circadian synthesis of SOD1 mRNA. Differences between young and older women found in the timing of 24-h maxima as well as differences observed in 24-h relationships between characters might be due to age-related alterations in the circadian system. Absence of relationships between levels of SOD1 and oxidative RNA/DNA damage argue for a more complex interaction between the antioxidant system and the circadian system.

Metabolomics of gingival crevicular fluid to identify biomarkers for periodontitis: A systematic review with meta-analysis

The present systematic review aimed to examine periodontitis-specific biomarkers in the gingival crevicular fluid (GCF) that could have a diagnostic relevance, and to provide a qualitative assessment of the current literature. Metabolites are reliable indicators of pathophysiological statuses, and their quantification in the GCF can provide an outlook of the changes associated with periodontitis and have diagnostic value. Relevant studies identified from PubMed, Embase, Cochrane Library, and Scopus databases were examined to answer the following PECO question: "In systemically healthy individuals, can concentration of specific metabolites in the GCF be used to discriminate subjects with healthy periodontium (H) or gingivitis from patients with periodontitis (P) and which is the diagnostic accuracy?" Quality of included studies was rated using a modified version of the QUADOMICS tool. Meta-analysis was conducted whenever possible. After the screening of 1,554 titles, 15 studies were selected, with sample size ranging from 30 to 93 subjects. Eleven studies performed targeted metabolomics analysis and provided data for 10 metabolites. Among the most consistent markers, malondialdehyde levels were found higher in the P group compared with H group (SMD = 2.86; 95% CI: 1.64, 4.08). Also, a significant increase of 8-hydroxy-deoxyguanosine, 4-hydroxynonenal, and neopterin was detected in periodontally diseased sites, while glutathione showed an inverse trend. When considering data from untargeted metabolomic analysis in four studies, more than 40 metabolites were found significantly discriminant, mainly related to amino acids and lipids degradation pathways. Notably, only one study reported measures of diagnostic accuracy. Several metabolites were differentially expressed in GCF of subjects across different periodontal conditions, having a major potential for investigating periodontal pathophysiology and for site-specific diagnosis. Oxidative stress-related molecules, such as malondialdehyde and 8-hydroxy-deoxyguanosine, were the most consistently associated to periodontitis (PROSPERO CRD42020188482).

Salivary and serum oxidative stress biomarkers and advanced glycation end products in periodontitis patients with or without diabetes: A cross-sectional study

BACKGROUND

Non-invasive methods for periodontitis diagnosis would be a clinically important tool. This cross-sectional study aimed to investigate the association between oxidative stress, glycation, and inflammation markers and periodontal clinical parameters in periodontitis and periodontally healthy patients with type 2 diabetes and corresponding systemically healthy controls.

METHODS

Sixty-seven periodontally healthy (DM-H, n = 32) and periodontitis (DM-P, n = 35) patients with type 2 diabetes, and 54 systemically healthy periodontitis (H-P, n = 26) and periodontally healthy (H-H, n = 28) controls were included. Clinical periodontal parameters, body mass index, fasting glucose, hemoglobin A1c (HbA1c), along with saliva and serum 8-hydroxy-2'-deoxyguanosine (8-OHdG), malondialdehyde (MDA), 4-hydroxy-2-nonenal (4-HNE), advanced glycation end products (AGE), AGE receptor (RAGE) and high sensitivity C-reactive protein (hsCRP) levels were recorded and analyzed.

RESULTS

Salivary 8-OHdG levels were significantly higher in periodontitis compared to periodontally healthy patients, regardless of systemic status (P < 0.001). Salivary MDA levels were significantly higher in all disease groups compared to H-H group (P ≤ 0.004). Serum AGE levels were significantly higher in diabetic groups than systemically healthy groups (P < 0.001) and in H-P compared to H-H (P < 0.001). Bleeding on probing (BOP) and clinical attachment level (CAL) strongly correlated with salivary 8-OHdG and serum hsCRP (P < 0.001). In systemically healthy patients, salivary 8-OHdG was the most accurate marker to differentiate periodontitis from controls (AUC = 0.84). In diabetics salivary 4-HNE and RAGE were the most accurate (AUC = 0.85 for both).

CONCLUSION

Salivary 8-OHdG alone or in combination with 4-HNE, AGE and RAGE for diabetics, and salivary 8-OHdG alone or in combination with MDA and hsCRP for systemically healthy persons, could potentially serve as non-invasive screening marker(s) of periodontitis.

THE INFLUENCE OF PERIODONTAL DISEASE TREATMENT ON 8-HYDROXY-DEOXYGUANOSINE CONCENTRATIONS IN SALIVA AND PLASMA OF CHRONIC PERIODONTITIS PATIENTS

The 8-hydroxy-deoxyguanosine (8-OHdG) is one of the customary products of oxidized DNA. The purpose of this study was to compare salivary and plasma 8-OHdG concentrations in a group of chronic periodontitis patients to those measured in a group of patients with healthy periodontium, as well as to determine the impact of periodontal therapy on 8-OHdG concentrations in saliva and plasma in chronic periodontitis patients. The study sample comprised of 24 patients with chronic periodontitis and 16 periodontally healthy individuals. Plaque index, gingival index, papilla bleeding index, probing depth and clinical attachment level were indices used to determine patient periodontal status. Salivary and plasma 8-OHdG concentrations were determined by ELISA method. The salivary 8-OHdG concentration was statistically significantly higher in the group of periodontitis patients compared to periodontally healthy subjects. After initial periodontal therapy, the 8-OHdG concentration in saliva was significantly reduced in the periodontitis group (p=0.021). Differences in plasma 8-OHdG concentrations between the two groups did not reach statistical significance and no significant changes were noted in the periodontitis group following initial periodontal therapy. A higher salivary 8-OHdG concentration reflects increased oxidative stress caused by periodontal disease. Initial periodontal therapy may be helpful in reducing salivary 8-OHdG concentrations in chronic periodontitis patients.

Interventions targeted at oxidatively generated modifications of nucleic acids focused on urine and plasma markers

Oxidative stress is associated with the development and progression of numerous diseases. However, targeting oxidative stress has not been established in the clinical management of any disease. Several methods and markers are available to measure oxidative stress, including direct measurement of free radicals, antioxidants, redox balance, and oxidative modifications of cellular macromolecules. Oxidatively generated nucleic acid modifications have attracted much interest due to the pre-mutagenic oxidative modification of DNA into 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), associated with cancer development. During the last decade, the perception of RNA has changed from that of a 'silent messenger' to an 'active contributor', and, parallelly oxidatively generated RNA modifications measured as 8-oxo-7,8-dihydro-guanosine (8-oxoGuo), has been demonstrated as a prognostic factor for all-caused and cardiovascular related mortality in patients with type 2 diabetes. Several attempts have been made to modify the amount of oxidative nucleic acid modifications. Thus, this review aims to introduce researchers to the measurement of oxidatively generated nucleic acid modifications as well as critically review previous attempts and provide future directions for targeting oxidatively generated nucleic acid modifications.

Synthesis, Characterization, Antimicrobial Activity, and Genotoxicity Assessment of Two Heterocyclic Compounds Containing 1,2,3-Selena- or 1,2,3-Thiadiazole Rings

New 1,2,3-thiadiazole and 1,2,3-selenadiazole derivatives, (4-[4-((4-bromobenzyl)oxy)-phenyl]-1,2,3-thiadiazole (5a), 4-[4-((4-chlorobenzyl)oxy)-phenyl]-1,2,3-thiadiazole (5b)), (4-[4-((4-bromobenzyl)oxy)-phenyl]-1,2,3-selenadiazole (6a), and 4-[4-((4-chlorobenzyl)oxy)-phenyl]-1,2,3-selenadiazole (6b)), were prepared and screened in vitro for their antimicrobial activity against various pathogenic microbes. In addition, two compounds (5a and 6a) were examined for their in vivo genotoxicity using rats and an 8-hydroxy-2′-deoxyguanosine (8-OHdG) assay. Compounds 5a and 5b were found to be highly active against Gram-positive and Gram-negative bacteria. In addition, a significant inhibition of urinary 8-OHdG level (50.2%) was observed upon treatment of animals with 500 mg/kg body weight (b.w.) of compound 6a (p < 0.0001). However, compound 5a increased urinary 8-OHdG levels. The lethal dose (LD₅₀) values for compounds 5a and 6a were determined by an up-and-down procedure (OECD 425; OECD 1998), which showed that these compounds are safe, since the LD₅₀ was >5000 mg/kg b.w. Thus, the tested compounds might have the potential for use as antibiotics, since they have low genotoxicity and strong antimicrobial activity.

Moderate Intensity Resistive Training Reduces Oxidative Stress and Improves Muscle Mass and Function in Older Individuals

An innovative moderate-intensity resistive exercise-training (RT) program was tested in thirty-five sarcopenic elders (SAR). The subjects were randomized into two groups: SAR training (SAR-RT), n = 20, 73.0 ± 5.5 years, or SAR non-training (SAR-NT), n = 15, 71.7 ± 3.4 years. The training consisted of 12-week progressive RT, thrice/week, at 60% one-repetition maximum (1RM), 3 sets, 14-16 repetitions for both upper and lower limbs. The pre and post intervention measurements included: the skeletal muscle index (SMI%); strength (1RM); stair-climbing power (SCP); muscle thickness (MT) of vastus lateralis (VL) and elbow flexors (EF), VL pennation angle (PA), rectus femoris (RF) anatomical cross-sectional area (ACSA); reactive oxygen species (ROS), total antioxidant capacity (TAC), protein carbonyls (PC), thiobarbituric acid-reactive substances (TBARS), 8-isoprostane (8-iso-PGF2-α), 8-OH-2-deoxyguanosine (8-OH-dG), as markers of oxidative stress/damage (OxS). In SAR-RT, SCP increased by 7.7% (P < 0.01), MT increased by 5.5% for VL, 10.4% for EF and PA increased by 13.4% for VL (P < 0.001 for all). The RF ACSA increased by 14.5% (P < 0.001). 1RM significantly increased by at least 67% for all muscles tested. Notably muscle strength (1RM) positively correlated (P < 0.001) with TAC and negatively with PC (P < 0.001). In conclusion, moderate intensity RT is an effective strategy to increase muscle mass and strength in SAR, while minimizing OxS.

Effect of H2 treatment in a mouse model of rheumatoid arthritis-associated interstitial lung disease

Rheumatoid arthritis (RA)-associated interstitial lung disease (ILD), a primary cause of mortality in patients with RA, has limited treatment options. A previously established RA model in D1CC transgenic mice aberrantly expressed major histocompatibility complex class II genes in joints, developing collagen II-induced polyarthritis and anti-cyclic citrullinated peptide antibodies and interstitial pneumonitis, similar to those in humans. Molecular hydrogen (H₂ ) is an efficient antioxidant that permeates cell membranes and alleviates the reactive oxygen species-induced injury implicated in RA pathogenesis. We used D1CC mice to analyse chronic lung fibrosis development and evaluate H₂ treatment effects. We injected D1CC mice with type II collagen and supplied them with H₂ -rich or control water until analysis. Increased serum surfactant protein D values and lung densities images were observed 10 months after injection. Inflammation was patchy within the perilymphatic stromal area, with increased 8-hydroxy-2'-deoxyguanosine-positive cell numbers and tumour necrosis factor-α, BAX, transforming growth factor-β, interleukin-6 and soluble collagen levels in the lungs. Inflammatory and fibrotic changes developed diffusely within the perilymphatic stromal area, as observed in humans. H₂ treatment decreased these effects in the lungs. Thus, this model is valuable for studying the effects of H₂ treatment and chronic interstitial pneumonia pathophysiology in humans. H₂ appears to protect against RA-ILD by alleviating oxidative stress.

In vivo evaluation of the genotoxicity and oxidative damage in individuals exposed to 10% hydrogen peroxide whitening strips

OBJECTIVE

This study assessed the impact of 10% hydrogen peroxide whitening strip exposure on the genotoxicity and oxidative damage by means of the buccal micronucleus cytome assay by counting nuclear abnormalities (NAs) in buccal mucosa and attached gingiva cells and by analyzing in whole saliva the molecule 8-hydroxy-2'-deoxyguanosine (8-OHdG).

MATERIALS AND METHODS

The study was conducted on 113 subjects divided into two groups: group 1 or control (n = 53), non-whitening strip exposed, and group 2 (n = 60), whitening strip exposed (Crest® 3D Whitestrips® premium plus, 10% hydrogen peroxide). Oral epithelial cells and whole saliva samples were taken at the beginning and 30 days later for group 1 and immediately before bleaching and 15 and 30 days after the end of the bleaching for group 2.

RESULTS

An increased frequency of NAs (p < 0.05) and higher levels of 8-OHdG (p < 0.05) were observed after bleaching exposure. Also, a positive correlation exists between oxidative stress produced by hydrogen peroxide and micronuclei was found.

CONCLUSION

Individuals exposed to 10% hydrogen peroxide whitening strips exhibit NAs increased in oral epithelial cells and 8-OHdG in saliva, which is directed related to nuclear and oxidative DNA damage, respectively.

CLINICAL SIGNIFICANCE

Hydrogen peroxide is the active agent of tooth whitening and this compound induced DNA damage. Individuals exposed to whitening strips with 10% hydrogen peroxide exhibit increased genotoxic and oxidative damage. Therefore, self-application of bleaching agents should be handled carefully since it could be a risk to human health.

The effect of periodontal therapy on oxidative stress biomarkers: A systematic review

AIM

To systematically review the literature about the effect of periodontal treatment on oxidative stress (OxS) biomarkers.

MATERIAL AND METHODS

Three databases (PubMed, EMBASE, and Scopus) were searched up to February 2018. Clinical trials with a follow-up of at least 6 weeks after mechanical periodontal treatment were included. Due to the high heterogeneity among the units and indices of measurements used in the studies, a meta-analysis was not performed.

RESULTS

Overall, 3,199 studies were retrieved, of which 20 were included. Four studies were randomized clinical trials (RCT), and 16 studies were non-RCTs. The most common OxS biomarkers used were 8-hydroxydeoxiguanosine (8-OHdG), total oxidant status (TOS), and total antioxidant status (TAS). After treatment, most of the studies reported a decrease in 8-OHdG concentration in the gingival crevicular fluid (GCF) and saliva. In addition, the salivary concentration of this biomarker was similar to periodontally healthy patients. Periodontal therapy was effective in reducing TOS in GCF, saliva, and serum in most studies. TAS, however, responded inconsistently to the periodontal intervention.

CONCLUSION

Periodontal therapy reduces the levels of OxS biomarkers, even to values similar to those found in periodontally healthy individuals. Additional RCTs are warranted, as the information is mainly based on nonrandomized studies.

Mitochondrial dysfunction and oxidative stress in aging and cancer

Aging and cancer are the most important issues to research. The population in the world is growing older, and the incidence of cancer increases with age. There is no doubt about the linkage between aging and cancer. However, the molecular mechanisms underlying this association are still unknown. Several lines of evidence suggest that the oxidative stress as a cause and/or consequence of the mitochondrial dysfunction is one of the main drivers of these processes. Increasing ROS levels and products of the oxidative stress, which occur in aging and age-related disorders, were also found in cancer. This review focuses on the similarities between ageing-associated and cancer-associated oxidative stress and mitochondrial dysfunction as their common phenotype.

The Effect of Moderate- Versus High-Intensity Resistance Training on Systemic Redox State and DNA Damage in Healthy Older Women

This study investigated effects of a 16-week progressive resistance training program (RTP) with elastic bands at two different intensities on systemic redox state, DNA damage, and physical function in healthy older women.

Methods:

Participants were randomly assigned to the high-intensity group (HIGH; n = 39), moderate-intensity group (MOD; n = 31), or control group (CG; n = 23). The exercise groups performed an RTP twice a week with three to four sets of 6 (HIGH) or 15 (MOD) repetitions of six overall body exercises at a perceived exertion rate of 8–9 on the OMNI-Resistance Exercise Scale for use with elastic bands. Thiol redox state was determined by reduced glutathione (GSH), oxidized glutathione (GSSG), and GSSG/GSH in blood mononuclear cells. Degree of DNA damage was assessed by presence of the oxidized DNA base molecule 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-OHdG) in urine. Physical function monitoring was based on the arm curl, chair stand, up and go, and 6-min walk tests.

Results:

The HIGH group showed a significant increase in 8-OHdG (+71.07%, effect size [ES] = 1.12) and a significant decrease in GSH (−10.91, ES = −0.69), while the MOD group showed a significant decrease in 8-OHdG levels (−25.66%, ES = −0.69) with no changes in thiol redox state. GSH levels differed significantly between the HIGH and CG groups posttest. The exercise groups showed significant improvements in physical function with no differences between groups.

Conclusion:

RTP at a moderate rather than high intensity may be a better strategy to reduce DNA damage in healthy older women while also increasing independence.

Mitochondrial haplogroups in patients with rheumatoid arthritis: No association with disease and disease manifestations

OBJECTIVE

To describe the distribution of specific mitochondrial DNA (mtDNA) haplogroups (hgs) in a cohort of patients with rheumatoid arthritis (RA).

METHODS

Two-hundred nineteen consecutive patients with RA had mtDNA isolated from their blood, sequenced and haplotyped. Patients were diagnosed according to the American College of Rheumatology (ACR)/European league against Rheumatism (EULAR) criteria. Demographic and clinical data were retrieved from the Danish nationwide database (DANBIO). Logistic regression analyses were performed to test for associations.

RESULTS

One-hundred eighty-four patients were eligible for analysis. Haplogroup frequencies were: H (n = 88; 47.8%), U (n = 37; 20.1%), T (n = 22; 12.0%), J (n = 16; 8.7%), K (n = 11; 5.9%), HV (n = 6; 3.3%) and V (n = 4; 2.2%). The distribution of individual hgs was identical to the background population. Radiographic erosions were significantly associated with hg clusters JT (OR = 2.37, 95% confidence interval (CI): 1.07-5.53, p = 0.038). Significantly fewer patients from hg cluster JT received biological treatment (OR = 0.17, 95% CI: 0.03-0.87, p = 0.038). Albeit, none of these associations were significant when corrected for multiple tests.

CONCLUSION

There was no significant association between mtDNA hgs and presence of RA or disease manifestations. There was an, albeit insignificant, overrepresentation of patients with hg JT among patients with erosive disease; however, slightly fewer patients in the JT group were treated with biological drugs.

Effects of dietary soy protein on skeletal muscle volume and strength in humans with various physical activities

BACKGROUND

In recent years, the number of bedridden people is rapidly increasing due to aging or lack of exercise in Japan. This problem is becoming more serious, since there is no countermeasure against it. In the present study, we designed to investigate whether dietary proteins, especially soy, had beneficial effects on skeletal muscle in 59 volunteers with various physical activities.

METHODS

We subjected 59 volunteers with various physical activities to meal intervention examination. Persons with low and high physical activities were divided into two dietary groups, the casein diet group and the soy diet group. They ate daily meals supplemented with 7.8 g of powdered casein or soy protein isolate every day for 30 days. Bedridden patients in hospitals were further divided into three dietary groups: the no supplementation diet group, the casein diet group and the soy diet group. They were also subjected to a blood test, a urinalysis, magnetic resonance imaging analysis and muscle strength test of the knee before and after the meal intervention study.

RESULTS

Thirty-day soy protein supplementation significantly increased skeletal muscle volume in participants with low physical activity, compared with 30-day casein protein supplementation. Both casein and soy protein supplementation increased the volume of quadriceps femoris muscle in bedridden patients. Consistently, soy protein significantly increased their extension power of the knee, compared with casein protein. Although casein protein increased skeletal muscle volume more than soy protein in bedridden patients, their muscle strength changes by soy protein supplementation were bigger than those by casein protein supplementation.

CONCLUSIONS

The supplementation of soy protein would be one of the effective foods which prevent the skeletal muscle atrophy caused by immobilization or unloading.

Impact of non-surgical periodontal therapy on saliva and serum levels of markers of oxidative stress

OBJECTIVE

The purpose of this study was to determine the effect of non-surgical periodontal treatment on markers of oxidative stress in saliva and serum in patients with chronic periodontitis.

MATERIALS AND METHODS

In total, 25 patients, who were diagnosed with generalized chronic periodontitis (11 females and 14 males), and 26 systemically and periodontally healthy individuals (15 females and 11 males) were included. The plaque index (PI), gingival index (GI), probing pocket depth (PPD), attachment loss (AL), gingival recession (GR), and bleeding on probing (BOP) were recorded at baseline and 6 weeks later. Malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), and 4-hydroxy-2-nonenal (4-HNE) were assessed in saliva and serum samples before and after the non-surgical treatment by enzyme-linked immune sorbent assay (ELISA).

RESULTS

In the group with chronic periodontitis, all clinical parameters were significantly higher compared to the control group at baseline (p < 0.001). Periodontal treatment reduced plaque, gingival inflammation, and pocket depth significantly (p < 0.001). At baseline, salivary 8-OHdG was significantly higher in chronic periodontitis (p < 0.001) and reduced significantly subsequent to the periodontal treatment (p < 0.001). Salivary MDA and serum 4-HNE were significantly higher in the patients with periodontitis compared to the control group (p < 0.001). Periodontal treatment did not significantly change the levels of 4-HNE and salivary MDA (p = 0.503, p = 0.093).

CONCLUSIONS

Salivary 8-OHdG and MDA may be associated with local impact of periodontal disease, while 4-HNE may be associated with systemic impact of chronic periodontitis.

CLINICAL RELEVANCE

Clinical intervention in periodontitis may be beneficial for periodontitis patients' systemic oxidative stress control, and using lipidic agents for the use of anti-inflammatory/pro-resolving processes for blocking the actions of arachidonic acid cascade can enable some late therapeutic strategies in order to lead oxidative stress-induced inflammation.

Radical Oxygen Species, Exercise and Aging: An Update

It is now well established that reactive oxygen species (ROS) play a dual role as both deleterious and beneficial species. In fact, ROS act as secondary messengers in intracellular signalling cascades; however, they can also induce cellular senescence and apoptosis. Aging is an intricate phenomenon characterized by a progressive decline in physiological functions and an increase in mortality, which is often accompanied by many pathological diseases. ROS are involved in age-associated damage to macromolecules, and this may cause derangement in ROS-mediated cell signalling, resulting in stress and diseases. Moreover, the role of oxidative stress in age-related sarcopenia provides strong evidence for the important contribution of physical activity to limit this process. Regular physical activity is considered a preventive measure against oxidative stress-related diseases. The aim of this review is to summarize the currently available studies investigating the effects of chronic and/or acute physical exercise on the oxidative stress process in healthy elderly subjects. Although studies on oxidative stress and physical activity are limited, the available information shows that acute exercise increases ROS production and oxidative stress damage in older adults, whereas chronic exercise could protect elderly subjects from oxidative stress damage and reinforce their antioxidant defences. The available studies reveal that to promote beneficial effects of physical activity on oxidative stress, elderly subjects require moderate-intensity training rather than high-intensity exercise.

Neuroprotective effect of peptides extracted from walnut (Juglans Sigilata Dode) proteins on Aβ25-35-induced memory impairment in mice

Alzheimer's disease (AD) is one of the major neurodegenerative disorders of the elderly, which is characterized by the accumulation and deposition of amyloid-beta (Aβ) peptide in human brains. Oxidative stress and neuroinflammation induced by Aβ in brain are increasingly considered to be responsible for the pathogenesis of AD. The present study aimed to determine the protective effects of walnut peptides against the neurotoxicity induced by Aβ25-35 in vivo. Briefly, the AD model was induced by injecting Aβ25-35 into bilateral hippocampi of mice. The animals were treated with distilled water or walnut peptides (200, 400 and 800 mg/kg, p.o.) for five consecutive weeks. Spatial learning and memory abilities of mice were investigated by Morris water maze test and step-down avoidance test. To further explore the underlying mechanisms of the neuroprotectivity of walnut peptides, the activities of superoxide dismutase (SOD), glutathione (GSH), acetylcholine esterase (AChE), and the content of malondialdehyde (MDA) as well as the level of nitric oxide (NO) in the hippocampus of mice were measured by spectrophotometric method. In addition, the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β) and IL-6 in the samples were determined using ELISA. The hippocampal expressions of inducible nitric oxide synthase (iNOS) and nuclear factor κB (NF-κB) were evaluated by Western blot analysis. The results showed that walnut peptides supplementation effectively ameliorated the cognitive deficits and memory impairment of mice. Meanwhile, our study also revealed effective restoration of levels of antioxidant enzymes as well as inflammatory mediators with supplementation of walnut peptides (400 or 800 mg/kg). All the above findings suggested that walnut peptides may have a protective effect on AD by reducing inflammatory responses and modulating antioxidant system.

Plasma and Synovial Fluid TrxR Levels are Correlated With Disease Risk and Severity in Patients With Rheumatoid Arthritis

This study was designed and performed to establish the relationship between plasma and synovial fluid (SF) levels of thioredoxin reductase (TrxR) and disease activity in Chinese patients with rheumatoid arthritis (RA).This study consisted of a total of 224 patients diagnosed with RA, 224 age and sex-matched healthy controls, and 156 patient controls. The disease activity of RA patients was calculated as diseases activity score that include 28-joint counts (DAS 28), which was divided into low-diseases activity (LDA) and high-diseases activity (HDA) groups.Increased plasma TrxR was detected in patients with RA than healthy controls (P < 0.0001). With an area under the curve (AUC) of 0.874, plasma TrxR showed a evidently greater discriminatory ability than C-reactive protein (CRP; AUC, 0.815), antistreptolysin-O (ASO; AUC, 0.631), rheumatoid factor (RF, AUC, 0.793), and erythrocyte sedimentation rate (ESR, AUC, 0.789) in diagnosing RA. RA patients with HDA had significantly elevated TrxR levels in plasma and SF than did those with LDA (P < 0.0001). With an AUC of 0.874, plasma TrxR levels as an indicator for screening of HDA showed a significantly greater discriminatory ability than CRP (AUC, 0.690), ASO (AUC, 0.597), RF (AUC, 0.657), and ESR (AUC, 0.603). Similarly, SF TrxR levels as an indicator for screening of HDA also showed a significantly greater discriminatory ability as compared with above biomarkers.TrxR levels in plasma and SF were positively correlated with the severity of RA. TrxR levels may therefore serve as a new biomarker in addition of the traditional biomarkers for assessing the risk and severity of RA. Further analysis of TrxR release machinery may give us a new understanding of pathogenesis of RA.

The association between systemic oxidative stress and ocular blood flow in patients with normal-tension glaucoma

PURPOSE

To evaluate the association between ocular blood flow and biomarkers of systemic oxidative stress, as well as the potential of these biomarkers to assess normal-tension glaucoma (NTG).

METHODS

This study included 73 eyes of 73 patients with NTG. We assessed ocular blood flow by measuring mean blur rate (MBR) in the optic nerve head using laser speckle flowgraphy, both overall and separately in the vessel and tissue areas. We also measured urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and skin autofluorescence (SAF), and lastly, determined correlations between these measurements and with other clinical parameters.

RESULTS

SAF was correlated with age, circumpapillary retinal nerve fiber layer thickness (cpRNFLT), mean deviation (MD), and overall MBR (P = 0.003, P = 0.013, P = 0.015 and P = 0.006, respectively). SAF and 8-OHdG were both correlated with tissue-area MBR (P = 0.006 and P = 0.010, respectively). Visual acuity, cpRNFLT, mean deviation and tissue-area MBR had a significant tendency to change with NTG severity (P = 0.014, P < 0.001, P < 0.001 and P = 0.006, respectively). Multiple regression analysis revealed that cpRNFLT and 8-OHdG were independent contributing factors to MD (P < 0.001 and P = 0.040, respectively), and that cpRNFLT and 8-OHdG were independent contributing factors to tissue-area MBR (P = 0.005 and P = 0.028, respectively).

CONCLUSIONS

We found a close relationship between cpRNFLT, MD, tissue MBR, SAF and 8-OHdG, suggesting that systemic oxidative stress is associated with decreased ocular blood flow and may be involved in the pathogenesis of NTG.

Oxidative stress and antioxidant responses to progressive resistance exercise intensity in trained and untrained males

The relationship between oxidative stress and some exercise components of resistance exercise (e.g. intensity, exercise volume) has not been clearly defined. Additionally, the oxidative stress markers may respond differently in various conditions. This study aims to determine the effects of progressive intensity of resistance exercise (RE) on oxidative stress and antioxidants in trained and untrained men, and also to investigate the possible threshold intensity required to evoke oxidative stress. RE trained (N=8) and untrained (N=8) men performed the leg extension RE at progressive intensities standardized for total volume: 1x17 reps at 50% of one-repetition maximum (1RM); 1x14 reps at 60% of 1RM; 1x12 reps at 70% of 1RM; 2x5 reps at 80% of 1RM; and 3x3 reps at 90% of 1RM. Blood samples were drawn before (PRE) and immediately after each intensity, and after 30 minutes, 60 minutes and 24 hours following the RE. Lipid-hydroperoxide (LHP) significantly increased during the test and then decreased during the recovery in both groups (p<0.05); the POST-24 h LHP level was lower than PRE-LHP. Protein carbonyl (PCO) and superoxide dismutase (SOD) significantly increased (p<0.05); however, 8-hydroxy-2’-deoxyguanosine (8-OHdG) and glutathione (GSH) were not affected by the RE (p > 0.05). The results indicated that there was no significant training status x intensity interaction for examined variables (p > 0.05). Standardized volume of RE increased oxidative stress responses. Our study suggests that lower intensity (50%) is enough to increase LHP, whereas higher intensity (more than 80%) is required to evoke protein oxidation.

Aggregation of rare/low-frequency variants of the mitochondria respiratory chain-related proteins in rheumatoid arthritis patients

Exome sequencings were conducted using 59 patients having rheumatoid arthritis (RA) and 93 controls. After stepwise filtering, 107 genes showed less than 0.05 of P-values by gene-burden tests. Among 107 genes, NDUFA7 which is a subunit of the complex I in the mitochondrial respiratory chain was selected for further analysis based on previous reports. A case-control study was performed on the three single-nucleotide variants (SNVs) of NDUFA7 with 432 cases and 432 controls. An association was observed between NDUFA7 and RA with severe erosive arthritis. These results together with previous reports suggested the involvement of reactive oxygen species (ROS) in the pathogenesis of RA. In the next step, four SNVs from three genes related to the mitochondrial respiratory chain were selected, which is a major source of ROS, and conducted a case-control study. An association was observed based on a pathway-burden test comprising NDUFA7, SDHAF2, SCO1 and ATP5O: P=1.56E-04, odds ratio=2.16, 95% confidence interval=1.43-3.28. Previous reports suggested the involvement of ROS in the pathogenesis of RA. The aggregation of SNVs in the mitochondria respiratory chain suggests the pivotal role of those SNVs in the pathogenesis of RA with severe erosive arthritis.

High sensitivity detection of salivary 8-hydroxy deoxyguanosine levels in patients with chronic periodontitis

BACKGROUND

Inflammation is associated with hydroxyl radical damage to DNA as a result of oxidative stress. 8-Hydroxy deoxyguanosine (8-OHdG) is a marker of this process and its levels in saliva could be linked to the severity of periodontal inflammation. The aim of this study was to test the sensitivity of liquid chromatography with tandem mass spectrometry (LC-MS/MS) in comparison to enzyme-linked immune sorbent assay (ELISA) for the detection of 8-OHdG in saliva in patients with chronic periodontitis before and after periodontal treatment.

METHODS

Saliva samples were collected from 23 patients (eight females and 15 males; 46.1 ± 5.1 years of age) with generalized chronic periodontitis and 25 (15 females and 10 males; 44.9 ± 6.8 years of age) periodontally healthy individuals. Patients received initial periodontal treatment consisting of scaling and root planing and were evaluated at baseline and after 6 wk of completion of non-surgical therapy. Salivary 8-OHdG levels were measured using ELISA and LC-MS/MS before and after the treatment. Clinically, plaque index, gingival index, clinical attachment level, bleeding on probing, gingival recession and probing pocket depth were measured at baseline and after 6 wk.

RESULTS

Salivary levels of 8-OHdG decreased significantly after the non-surgical periodontal treatment (p < 0.001). Statistically significant positive correlations were observed between plaque index, gingival index, probing pocket depth, clinical attachment level, bleeding on probing values and LC-MS/MS and ELISA levels of 8-OHdG (p < 0.001).

CONCLUSION

LC-MS/MS is a reliable and sensitive method for evaluating salivary 8-OHdG levels to monitor the treatment response of periodontitis.

Effect of initial periodontal therapy on oxidative stress markers in gingival crevicular fluid, saliva, and serum in smokers and non-smokers with chronic periodontitis

BACKGROUND

The aim of this case-control study with an intervention arm is to determine the effect of initial periodontal treatment on oxidative stress biomarkers in smokers and non-smokers with chronic periodontitis (CP).

METHODS

The study included 47 patients with CP (24 smokers [S+P+] and 23 non-smokers [S-P+]) and 46 periodontally healthy individuals (23 smokers [S+P-] and 23 non-smokers [S-P-]) for a total of 93 participants. Gingival crevicular fluid (GCF), serum, and saliva samples were obtained and clinical periodontal measurements were recorded at baseline and at the first and third months after periodontal therapy. 8-hydroxydeoxyguanosine (OHdG) and 4-hydroxynonenal (HNE) and enzyme activity of glutathione peroxidase (GSH-Px) were analyzed with enzyme-linked immunosorbent assay.

RESULTS

The level of 8-OHdD in GCF was found to be significantly higher in both periodontitis groups compared with both periodontally healthy groups. 8-OHdG and GSH-Px in saliva in both periodontitis groups were significantly increased compared with the S-P- group. In the S+P+ group, 4-HNE in GCF was found to be significantly higher than in periodontally healthy participants. After initial periodontal treatment, the levels of 8-OHdG in GCF and saliva were significantly decreased in both periodontitis groups.

CONCLUSION

Initial periodontal therapy may be helpful for diminishing oxidative stress in periodontitis.

Multimarker screening of oxidative stress in aging

Aging is a complex process of organism decline in physiological functions. There is no clear theory explaining this phenomenon, but the most accepted one is the oxidative stress theory of aging. Biomarkers of oxidative stress, substances, which are formed during oxidative damage of phospholipids, proteins, and nucleic acids, are present in body fluids of diseased people as well as the healthy ones (in a physiological concentration). 8-iso prostaglandin F_2α is the most prominent biomarker of phospholipid oxidative damage, o-tyrosine, 3-chlorotyrosine, and 3-nitrotyrosine are biomarkers of protein oxidative damage, and 8-hydroxy-2^′-deoxyguanosine and 8-hydroxyguanosine are biomarkers of oxidative damage of nucleic acids. It is thought that the concentration of biomarkers increases as the age of people increases. However, the concentration of biomarkers in body fluids is very low and, therefore, it is necessary to use a sensitive analytical method. A combination of HPLC and MS was chosen to determine biomarker concentration in three groups of healthy people of a different age (twenty, forty, and sixty years) in order to find a difference among the groups.

Molecular hydrogen: new antioxidant and anti-inflammatory therapy for rheumatoid arthritis and related diseases

Rheumatoid arthritis (RA) is a chronic inflammatory disease in which the progressive destruction of joint causes morbidity. It is also associated with an increased risk of atherosclerosis, which can result in cardiovascular disease and mortality. The therapeutic goal is to control the systemic inflammation to obtain not only the remission of symptoms, but also improve general state of health. Although recent biologic immunosuppressive therapies targeting pro-inflammatory cytokines have spawned a paradigm shift regarding the prognosis of RA, these therapies possess inherent side effects. Also, early diagnosis of the disease remains confounded by uncertainty. While the mechanisms responsible for the onset of RA remain unclear, reactive oxygen species (ROS) play a significant role in the pathogenesis of RA. ROS play a central role both upstream and downstream of NF-κB and TNFα pathways, which are located at the center of the inflammatory response. Among the ROS, the hydroxyl radical is the most harmful, and molecular hydrogen (H2) is a selective scavenger for this species. Recently, it has been shown that H2 is useful when administered along with the conventional therapy in RA as it acts to reduce oxidative stress in the patients. Especially in the early stage, H2 showed significant therapeutic potential, which also seemed to assist diagnosis and treatment decisions of RA. The possible expectations regarding the potential benefits of H2 by reducing the oxidative stress, resulting from inflammatory factors, are raised and discussed here. They include prevention of RA and related atherosclerosis, as well as therapeutic validity for RA

Three months of moderate-intensity exercise reduced plasma 3-nitrotyrosine in rheumatoid arthritis patients

PURPOSE

Rheumatoid arthritis (RA) patients display high levels of oxidative stress. Transient exercise-induced increases in oxidative stress are thought to be adaptive in healthy populations. This study investigated the effect of exercise on markers of oxidative stress in RA, following acute exercise and a period of exercise training.

METHODS

Acute exercise study: RA patients (N = 12, age: 56 ± 11) undertook a bout of exercise (30-40 min, 70 % VO2MAX), and blood samples were taken before and after exercise to assess markers of oxidative stress. Training study: RA patients (N = 19, age: 56 ± 10) were randomised into either a control or exercise group, who undertook 3 exercise sessions per week (30-40 min @70 % VO2MAX) for 3 months. Plasma markers of oxidative stress (protein carbonyls (PC), lipid hydroperoxides (LOOH), 3-nitrotyrosine (3-NT), total antioxidant capacity (TAC) and catalase (CAT) activity), inflammation (interleukin-8 (IL-8) and C-reactive protein (CRP)) and nitric oxide metabolites (NOx) were assessed before and after training.

RESULTS

Acute exercise study: Protein carbonyls (PC) (+18 %) and NOx (+27 %) were significantly increased following exercise. Training study: 3-nitrotyrosine (3-NT) decreased (2.18 ± 1.78 to 1.10 ± 0.93 μM) in the exercise group only, alongside increases in aerobic fitness (24.45 ± 4.98 to 27.10 ± 4.51 ml/kg/min(-1)) and reductions in disease activity score (DAS: 3.47 ± 1.17 to 2.88 ± 0.76). PC, LOOH, TAC, IL-8, CRP and NOx concentrations, and CAT activity were unchanged in both groups.

CONCLUSIONS

Aerobic exercise training did not increase markers of oxidative stress in RA patients. 3-Nitrotyrosine and disease activity were decreased following exercise training.

8-hydroxy-deoxyguanosine levels in gingival crevicular fluid and saliva in patients with chronic periodontitis after initial periodontal treatment

BACKGROUND

This study evaluates the effects of initial periodontal treatment on the gingival crevicular fluid (GCF) and salivary levels of 8-hydroxy-deoxyguanosine (8-OHdG) as a marker of oxidative deoxyribonucleic acid (DNA) damage in patients with chronic periodontitis (CP).

METHODS

At baseline, clinical parameters were determined and GCF and saliva samples were obtained from 24 patients with CP and 24 individuals with clinically healthy periodontium. GCF, saliva samples, and clinical periodontal measurements were repeated at day 10, 1 month, and 3 months following initial periodontal therapy in patients with CP. 8-OHdG levels of GCF and saliva samples were investigated by using an enzyme-linked immunosorbent assay.

RESULTS

Statistically significant higher 8-OHdG levels of GCF and a significant decrease after initial periodontal therapy were determined in the CP group (P <0.001). A significant positive correlation was found between 8-OHdG levels of GCF and clinical periodontal measurements (P <0.001). However, salivary levels of 8-OHdG did not differ between groups or during initial periodontal therapy (P >0.05).

CONCLUSIONS

This study reveals that DNA injury and oxidative stress increase in tissue cells and especially in periodontal pockets in patients with CP, and the periodontal treatment results in a significant decrease of 8-OHdG levels in the GCF samples. To the best of our knowledge, this study evaluates for the first time, 8-OHdG levels in GCF, which is shown to be more useful as a biomarker than saliva. 8-OHdG was found to be important and may reveal the severity of periodontal disease and the effect of periodontal therapy.

The effect of caloric restriction and glycemic load on measures of oxidative stress and antioxidants in humans: results from the CALERIE Trial of Human Caloric Restriction

Decreasing oxidative stress and increasing antioxidant defense has been hypothesized as one mechanism by which caloric restriction (CR) increases longevity in animals. A total of 46 moderately overweight volunteers (BMI: 25-30 kg/m2), ages 20-42 yr were randomized to either high glycemic (HG) or low glycemic (LG) dietary load CR regimen at either 10% (n=12) or 30% (n=34) of basal caloric intake. All food was provided to participants for 6 mo. Overall, after controlling for CR levels and dietary regimen for 6 mo, plasma glutathione peroxidase activity increased (p=0.04) and plasma protein carbonyl levels decreased (p=0.02) and a non-significant decrease in plasma 8-epi-prostaglandin F2α level was observed (p=0.09). No significant change was observed in other plasma antioxidants such as superoxide dismutase and catalase. These findings indicate that short term CR (10% or 30%) in moderately overweight subjects modulates some but not all measures of antioxidant defense and oxidative stress.

Effects of Treatment Intensity in Upper Limb Robot-Assisted Therapy for Chronic Stroke

Background and Objectives. Robot-assisted therapy (RT) is a current promising intervention in stroke rehabilitation, but more research is warranted for examining its efficacy and the dose–benefit relation. The authors investigated the effects of higher intensity versus lower intensity RT on movements of forearm pronation–supination and wrist flexion–extension relative to conventional rehabilitation (CR) in patients poststroke for a mean of 21 months. Methods. In this pilot study, 18 patients with initial mean Fugl-Meyer Assessment (FMA) of 37 to 44 for the upper extremity were randomized to higher intensity RT, lower intensity RT, or CR intervention for 4 weeks. The dose of the higher intensity RT was twice the number of repetitions in the lower intensity RT. Outcome measures at pretreatment and posttreatment were administered to patients to evaluate beneficial and adverse effects of interventions. Primary outcomes were the FMA and Medical Research Council scale. Results. There were significant differences in motor function ( P = .04) and daily performance ( P = .03) among the 3 groups. The higher intensity RT group showed better improvement in motor function, muscle strength, performance of daily activities, and bimanual ability than the other 2 groups. The intensive RT intervention did not induce higher levels of an oxidative DNA biomarker. Conclusions. Higher intensity of RT that assists forearm and wrist movements may lead to greater improvement in motor ability and functional performance in stroke patients. A sample size of only 20 to 25 in each arm of a larger randomized controlled trial is needed to confirm the findings for similar subjects.

Oxidative stress and antioxidant defense mechanisms linked to exercise during cardiopulmonary and metabolic disorders

Oxidative stress has been implicated in the pathophysiology of multiple human diseases, in addition to the aging process. Although various stimuli exist, acute exercise is known to induce a transient increase in reactive oxygen and nitrogen species (RONS), evident by several reports of increased oxidative damage following acute bouts of aerobic and anaerobic exercise. Although the results are somewhat mixed and appear disease dependent, individuals with chronic disease experience an exacerbation in oxidative stress following acute exercise when compared to healthy individuals. However, this increased oxidant stress may serve as a necessary “signal” for the upregulation in antioxidant defenses, thereby providing protection against subsequent exposure to prooxidant environments within susceptible individuals. Here we present studies related to both acute exercise-induced oxidative stress in those with disease, in addition to studies focused on adaptations resulting from increased RONS exposure associated with chronic exercise training in persons with disease.

Interaction between oxidative stress and high-density lipoprotein cholesterol is associated with severity of coronary artery calcification in rheumatoid arthritis

OBJECTIVE

To test the hypothesis that oxidative stress is increased in patients with rheumatoid arthritis (RA) due to increased inflammation and contributes to the pathogenesis of atherosclerosis.

METHODS

The independent association between urinary F₂-isoprostane excretion, a measure of oxidative stress, and RA was tested using multiple linear regression models in 169 patients with RA and 92 control subjects, frequency matched for age, race, and sex. The relationship between F₂-isoprostane excretion and coronary calcium, a marker of atherosclerosis, was examined in multivariable proportional odds logistic regression models that also assessed the interactions between oxidative stress and low-density lipoprotein and high-density lipoprotein (HDL) cholesterol.

RESULTS

F₂-isoprostane excretion was significantly higher in patients with RA (median 2.75 [interquartile range (IQR) 1.60-4.06] ng/mg creatinine) than in control subjects (median 1.86 [IQR 1.25-2.62] ng/mg creatinine; adjusted P = 0.006). In patients with RA, F₂-isoprostanes were positively correlated with body mass index (P < 0.001), but not with disease activity or mediators of inflammation such as the Disease Activity Score in 28 joints or serum tumor necrosis factor α, interleukin-6, and C-reactive protein concentrations in adjusted multivariable models (P > 0.05 for all). In patients with RA, F₂-isoprostanes significantly modified the effect of HDL cholesterol on coronary calcification (P = 0.02 for interaction) after adjustment for age, sex, and race. As F₂-isoprostane levels increased, HDL lost its protective effect against coronary calcification.

CONCLUSION

Oxidative stress measured as F₂-isoprostane excretion was higher in patients with RA than in control subjects. Among patients with RA, higher F₂-isoprostane excretion and HDL cholesterol concentrations interacted significantly and were positively associated with the severity of coronary calcification.

Evaluation of therapeutic effects of astaxanthin on impairments in salivary secretion

The involvement of reactive oxygen species (ROS) in the pathophysiology of Sjögren's syndrome (SS), an autoimmune disorder, and irradiation-induced impairments in salivary secretion has been reported. Meanwhile, the strong antioxidant astaxanthin (Ast) has been suggested to have therapeutic effects on various diseases. In the present study, we examined the ROS scavenging capacity of Ast using a human salivary gland epithelial cell line (HSY) and investigated the effects of Ast on salivary secretion in a mouse model of irradiation-induced salivary gland dysfunction. Furthermore, we performed a clinical study of Ast in six SS patients and six normal individuals, quantifying the volume of saliva secretion and the level of oxidative stress markers in the saliva. Ast partially suppressed hydrogen peroxide-induced ROS in HSY cells. The mouse model demonstrated that the pre-administration of Ast resulted in the suppression of irradiation-induced hyposalivation. Furthermore, the administration of Ast appeared to increase salivary output in both the SS and normal groups. The level of oxidative stress marker, hexanoyl-lysine, in the saliva was reduced after Ast intake. These results suggest that Ast might act as an ROS scavenger, providing benefits to SS patients with impaired salivary secretion.

Urinary 8-OHdG: A marker of oxidative stress to DNA and total antioxidant status in essential hypertension with South Indian population

Establishment of non-invasive urinary biomarker for the early prediction of essential hypertension (EH) is important. We evaluated whether estimation of urinary DNA, serves as a marker to predict the extent of cellular oxidative stress in essential hypertension. A total of 180 South Indian subjects aged 30-65 were recruited for the study. Of these hypertensive subjects investigated, 30 were newly diagnosed and were not on any antihypertensive drugs, but had systolic blood pressure 140-160 mmHg and diastolic blood pressure 95-100 mmHg and 75 hypertensive patients who already on drug therapy for one year and 75 were South Indian normotensive healthy controls with blood pressure ≤ 120/80 mmHg. The 8-OHdG level in urine was significantly increased in hypertensive patients (both newly diagnosed and who already on drug therapy) compared with control group. The significant increase in 8-OHdG was observed in newly diagnosed hypertensive patients compared with hypertensive patients who already on drug therapy. There was a significant decrease in serum TAS value in essential hypertensive group when compared to control group. The urinary 8-OHdG was independently correlated with serum TAS. Decreased TAS levels, which reflect to increased oxidative stress, may be the reason of increased urinary 8-OHdG in South Indian hypertensive patients. Our preliminary data suggest that the competitive ELISA for 8-OHdG appears to be a simple method for quantifying the extent of oxidative stress.

Selenite induces oxidative DNA damage in primary rat hepatocyte cultures

The effects of selenite ions on oxidative DNA damage in primary rat hepatocyte cultures were examined. Selenite ions dose-dependently stimulated 8-hydroxydeoxyguanosine formation in DNA from the hepatocyte cultures at concentrations of 1, 5 and 10 micromol/L (1.6-, 2.5- and 3.6-fold). Selenite ions also induced DNA fragmentation in nucleus from the hepatocyte cultures at concentrations of 5 and 10 micromol/L. Selenite ions could not affect protein expression levels of 8-oxoguanine DNA glycosylase 1 which is responsible for excision of 8-hydroxydeoxyguanosine from DNA, but could increase 2',7'-dichlorofluorescein-fluorescence intensity from 2',7'-dichlorodihydrofluorescein, an indicator of reactive oxygen species generation, at concentrations of 5 and 10 micromol/L. Furthermore, an increase in 8-hydroxydeoxyguanosine induced by selenite ions (10 micromol/L) was inhibited by free radical scavengers (alpha-tocopherol, N-acetyl-L-cysteine, and melatonin) at concentrations more than 50 micromol/L. These observations imply that selenite ions have the potential to induce oxidative DNA damage in the liver through an increase in reactive oxygen species formation, but not a decrease in 8-oxoguanine DNA glycosylase 1 protein expression levels.

Evaluation of a Multi-parameter Biomarker Set for Oxidative Damage in Man: Increased Urinary Excretion of Lipid, Protein and DNA Oxidation Products after One Hour of Exercise

The objective of the present study was to evaluate a comprehensive set of urinary biomarkers for oxidative damage to lipids, proteins and DNA, in man. Eighteen moderately trained males (mean age 24.6+/-0.7) exercised 60min at 70% of maximal O2 uptake on a cycle ergometer. Urine fractions for 12 h were collected 1 day before, and for 3 consecutive days after exercise. As biomarkers of lipid peroxidation, 8 aldehydes (i.e. propanal, butanal, pentanal, hexanal, heptanal, octanal, nonanal and malondialdehyde-MDA)and acetone were analyzed in urines by gas chromatography with electron capture detection (GC-ECD). As a biomarker of protein oxidation, o,o'-dityrosine was analyzed in urine samples by a recently developed isotope dilution HPLC-atmospheric pressure chemical ionization (APCI)-tandem-mass spectrometry (HPLC-APCI-MS/MS) methodology. As a biomarker of oxidative DNA damage, urinary excretion of 8-hydroxy-2'-deoxyguanosine (8-OHdG) was measured by an ELISA method. On the day of exercise, significant increases were observed in urinary excretions of acetone (p < 0.025, n = 18) and butanal (p < 0.01, n = 18) in the 12h daytime fractions compared to the daytime fraction before exercise. The urinary acetone excretion was also significantly (p < 0.05) increased on the 1st day after exercise. Octanal and nonanal were increased in the daytime urine fraction on the 2nd day after exercise. However, these increases were of borderline significance (p = 0.09 and p = 0.07, respectively). Significantly elevated urinary o,o'-dityrosine amounts were observed in the daytime fraction on the day of exercise (p < 0.025) and on the 1st day after exercise (p = 0.07) compared to the before exercise daytime fraction. Excretion of urinary 8-OHdG was statistically significantly increased in the daytime fractions on the day of exercise (p = 0.07) and on the 1st day after exercise (p < 0.025) compared to before exercise daytime fraction. Increases in urinary excretions of acetone, propanal, pentanal, MDA and 8-OHdG significantly correlated with training status (hours of exercise/week) of the volunteers, while o,o'-dityrosine did not. To our knowledge, the present study is the first to evaluate a multi-parameter non-invasive biomarker set for damage to three main cellular targets of ROS. It shows that 1 h of exercise may already induce oxidative damage in moderately trained individuals and that the chosen urinary biomarkers are sensitive enough to monitor such damage.

Physical activity modulates heat shock protein-72 expression and limits oxidative damage accumulation in a healthy elderly population aged 60 90 years

BACKGROUND

Reactive oxygen species production increases during aging, whereas protective mechanisms such as heat shock proteins (HSPs) or antioxidant capacity are depressed. Physical activity has been hypothesized to provide protection against oxidative damage during aging, but results remain controversial. This study aimed to investigate the effect of different levels of physical activity during aging on Hsp72 expression and systemic oxidative stress at rest and in response to maximal exercise.

METHODS

Plasma antioxidant capacity (Trolox equivalent antioxidant capacity, TEAC), thiobarbituric acid-reactive species (TBARS), advanced oxidized proteins products (AOPP), and Hsp72 expression in leukocytes were measured before and after maximal exercise testing in 32 elderly persons (aged 73.2 years), who were assigned to two different groups depending on their level of physical activity during the past 12 months (OLow = moderate to low level; OHigh = higher level).

RESULTS

The OHigh group showed higher aerobic fitness and TEAC (both representing 120% of OLow values) as well as lower oxidative damage (50% of OLow values) and Hsp72 expression. Exercise led to a lower increase in oxidative damage in the OHigh group. Aerobic fitness was positively correlated with TEAC and negatively with lipid peroxidation (TBARS). Hsp72 expression was negatively correlated with TEAC but positively correlated with TBARS levels.

CONCLUSIONS

The key finding of this study is that, in people aged 60 to 90 years, long-term high level of physical activity preserved antioxidant capacity and limited oxidative damage accumulation. It also downregulated Hsp72 expression, an adaptation potentially resulting from lower levels of oxidative damage.

Etanercept reduces the oxidative stress marker levels in patients with rheumatoid arthritis

This study was performed to evaluate the effects of the TNF-alpha inhibitor etanercept on oxidation stress markers representing DNA damage, lipid peroxidation, and protein glycosylation. Twenty-two rheumatoid arthritis (RA) patients underwent etanercept treatment. The levels of serum total, urinary total, and urinary free pentosidine, which is an advanced glycation end-product (AGE), of urinary N(epsilon)-hexanoyl lysine (N(epsilon)-HEL), and of 8-hydroxy-deoxy guanosine (8-OHdG) were measured at baseline and at 3 and 6 months after the initial treatment with etanercept. Serum total and urinary total pentosidine levels were reduced at 6 months after the initial treatment with etanercept, and urinary free pentosidine levels were reduced at 3 and 6 months. Urinary N(epsilon)-HEL levels were also reduced at 3 and 6 months, and urinary 8-OHdG levels were reduced at 6 months. Serum total and urinary total pentosidine levels in RA patients correlated with the number of swelling joints and tender joints, and urinary total pentosidine levels correlated with the Disease Activity Score using 28 joints (DAS28). This study demonstrated that etanercept acts as a regulator against pentosidine formation, oxidative DNA damage, and lipid peroxidation in RA patients.

Early Increase of Oxidative Stress and Soluble CD40L in Children With Hypercholesterolemia

OBJECTIVES

The aim of the study was to analyze the behavior of oxidative stress and its interplay with CD40L, a protein that is implicated in atherosclerosis, in hypercholesterolemic children.

BACKGROUND

Oxidative stress has been suggested to play a major role in premature atherosclerosis.

METHODS

Forty-one children with hypercholesterolemia (mean age 9.28 +/- 0.5 years) and 40 children with normocholesterolemia (mean age 9.02 +/- 0.69 years) were matched for gender and age. Within each group, children were classified as having or not having a family history of cardiovascular disease. Serum levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress, and plasma levels of soluble CD40L (sCD40L) were measured in each child. In a subgroup of children with high (n = 8) or normal (n = 8) levels of serum cholesterol, platelet p38 mitogen-activated protein (MAP) kinase phosphorylation, a protein involved in the activation of nicotinamide adenine dinucleotide phosphate oxidase, was determined.

RESULTS

Children with hypercholesterolemia had higher values of 8-OHdG and sCD40L compared with control subjects (0.55 +/- 0.06 ng/ml vs. 0.21 +/- 0.02 ng/ml, p < 0.001 and 0.55 +/- 0.04 ng/ml vs. 0.19 +/- 0.03 ng/ml, p < 0.001, respectively). A significant correlation between 8-OHdG and sCD40L was observed in children with high (r = 0.676, p < 0.001) or normal (r = 0.878, p < 0.001) levels of cholesterol. Children with a family history of cardiovascular disease tended to have higher values of 8-OHdG and sCD40L, but the difference was not significant. Analysis of platelet p38 MAP kinase showed that it was phosphorylated more in children with hypercholesterolemia compared with control subjects (36.8 +/- 5.8 AU vs. 8.0 +/- 4.5 AU, p < 0.001 respectively).

CONCLUSIONS

Children with hypercholesterolemia have an early increase of oxidative stress that may be responsible for up-regulation of CD40L and potentially predispose to premature atherosclerosis.

Analyses of representative biomarkers of exposure and effect by chromatographic, mass spectrometric, and nuclear magnetic resonance techniques: method development and application in life sciences

Biomarkers are essential tools in monitoring studies, which include environmental monitoring, biological monitoring, biological effect monitoring, and health surveillance, as well as drug development processes. Their discovery, validation, and analysis require highly sensitive and selective analytical technologies. In this regard, gas and liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopy have facilitated great achievements in all these areas. In addition and closely related to biomarkers, the ongoing developments in these techniques promise a better understanding of the nature and mechanisms of toxic effects originating from various chemical, biological, or physical sources. This Review compiles studies performed on selected biomarkers with respect to both method development and application. Section 1 summarizes the concept of biomarkers; their application in various industrial/occupational, agricultural, drug developmental, and medical/clinical platforms. This section also focuses on biotransformation studies in close relation to biomarker discovery and validation, and on major techniques utilized in this area. In Section 2, biotransformation of volatile anesthetics in humans with a focus on mercapturic acid derivatives as potential biomarkers of effect is reviewed. The use of GC-ECD, GC/MS, and 19F-NMR in these studies is described. Section 3 focuses on the analysis of aldehydic lipid peroxidation degradation products by GC-ECD in mammalian cells in which oxidative stress induced chemically, and in humans after various challenges; anesthetic exposure, ischemia-reperfusion, and controlled endurance exercise. In Section 4, method development for protein and DNA oxidation products by LC-tandem MS and its application in mammalian cells and in humans are summarized. Possibilities, limitations, and future perspectives are discussed in Section 5.

The rheumatoid arthritis shared epitope increases cellular susceptibility to oxidative stress by antagonizing an adenosine-mediated anti-oxidative pathway

We have recently demonstrated that the rheumatoid arthritis (RA) shared epitope (SE) acts as a ligand that triggers nitric oxide (NO) signaling in opposite cells. Given the known pro-oxidative effect of NO and the proposed role of oxidative stress in the pathogenesis of RA, this study explores whether SE-triggered signaling can increase cellular oxidative stress. cAMP levels, adenylyl cyclase activity, and protein kinase A activity were measured using commercial kits. Generation of reactive oxygen species (ROS) was quantified using the fluorochrome dichlorofluorescein diacetate. Oxidative DNA damage was quantified using the single-cell electrophoresis technique. Here, we report that cells exposed to cell surface SE-positive HLA-DR (human leukocyte antigen-DR) molecules, to cell-free recombinant proteins genetically engineered to express the SE motif, or to SE-positive synthetic peptide showed diminished cAMP-dependent signaling, increased ROS levels, and higher vulnerability to oxidative DNA damage. Introduction of single amino acid substitutions into SE-positive peptides revealed a consensus five-amino acid sequence motif of Q/R-K/R-X-X-A that is necessary and sufficient for SE-triggered signaling. The pro-oxidative effect of the SE could be reversed by inhibiting NO production. We conclude that the SE acts as a signaling ligand that activates an NO-mediated pro-oxidative pathway. The potential contribution of this signaling aberration to RA pathogenesis is discussed.

Possible involvement of oxidative stress in salivary gland of patients with Sjogren's syndrome

OBJECTIVE

To determine the involvement of oxidative stress in the salivary gland of patients with Sjogren's syndrome (SS).

METHODS

Oxidative damage to the gland was measured by 8-hydroxy-2'-deoxyguanosine (8-OHdG) and hexanoyl-lysine (HEL) using the SS saliva. In addition, lactate dehydrogenase (LDH) and mitochondrial glutamic-oxaloacetic transaminase (m-GOT), both general markers for cell damage, were also analyzed.

RESULTS

Increased levels of 8-OHdG and HEL were found in the saliva of SS patients, but not in that of patients with other salivary gland dysfunction or of healthy individuals. Levels of LDH and m-GOT were significantly correlated with 8-OHdG and HEL levels, respectively. Furthermore, the increased levels of 8-OHdG and HEL were also correlated in the SS saliva.

CONCLUSION

These findings suggested the involvement of oxidative stress in glandular tissue destruction in SS. It was indicated that the detection of 8-OHdG and HEL in the saliva may become a useful tool for the diagnosis of SS.

Oxidative stress : relationship with exercise and training

Free radicals are reactive compounds that are naturally produced in the human body. They can exert positive effects (e.g. on the immune system) or negative effects (e.g. lipids, proteins or DNA oxidation). To limit these harmful effects, an organism requires complex protection - the antioxidant system. This system consists of antioxidant enzymes (catalase, glutathione peroxidase, superoxide dismutase) and non-enzymatic antioxidants (e.g. vitamin E [tocopherol], vitamin A [retinol], vitamin C [ascorbic acid], glutathione and uric acid). An imbalance between free radical production and antioxidant defence leads to an oxidative stress state, which may be involved in aging processes and even in some pathology (e.g. cancer and Parkinson's disease). Physical exercise also increases oxidative stress and causes disruptions of the homeostasis. Training can have positive or negative effects on oxidative stress depending on training load, training specificity and the basal level of training. Moreover, oxidative stress seems to be involved in muscular fatigue and may lead to overtraining.