Simvastatin and oxidative stress in humans: A randomized, double-blinded, placebo-controlled clinical trial

Longitudinal Plasma Metabolome Patterns and Relation to Kidney Function and Proteinuria in Pediatric CKD

Key Points

Longitudinal untargeted metabolomics. Children with CKD have a circulating metabolome that changes over time.

Background

Understanding plasma metabolome patterns in relation to changing kidney function in pediatric CKD is important for continued research for identifying novel biomarkers, characterizing biochemical pathophysiology, and developing targeted interventions. There are a limited number of studies of longitudinal metabolomics and virtually none in pediatric CKD.

Methods

The CKD in Children study is a multi-institutional, prospective cohort that enrolled children aged 6 months to 16 years with eGFR 30–90 ml/min per 1.73 m2. Untargeted metabolomics profiling was performed on plasma samples from the baseline, 2-, and 4-year study visits. There were technologic updates in the metabolomic profiling platform used between the baseline and follow-up assays. Statistical approaches were adopted to avoid direct comparison of baseline and follow-up measurements. To identify metabolite associations with eGFR or urine protein-creatinine ratio (UPCR) among all three time points, we applied linear mixed-effects (LME) models. To identify metabolites associated with time, we applied LME models to the 2- and 4-year follow-up data. We applied linear regression analysis to examine associations between change in metabolite level over time (∆level) and change in eGFR (∆eGFR) and UPCR (∆UPCR). We reported significance on the basis of both the false discovery rate (FDR) <0.05 and P < 0.05.

Results

There were 1156 person-visits (N : baseline=626, 2-year=254, 4-year=276) included. There were 622 metabolites with standardized measurements at all three time points. In LME modeling, 406 and 343 metabolites associated with eGFR and UPCR at FDR <0.05, respectively. Among 530 follow-up person-visits, 158 metabolites showed differences over time at FDR <0.05. For participants with complete data at both follow-up visits (n =123), we report 35 metabolites with ∆level–∆eGFR associations significant at FDR <0.05. There were no metabolites with significant ∆level–∆UPCR associations at FDR <0.05. We report 16 metabolites with ∆level–∆UPCR associations at P < 0.05 and associations with UPCR in LME modeling at FDR <0.05.

Conclusions

We characterized longitudinal plasma metabolomic patterns associated with eGFR and UPCR in a large pediatric CKD population. Many of these metabolite signals have been associated with CKD progression, etiology, and proteinuria in previous CKD Biomarkers Consortium studies. There were also novel metabolite associations with eGFR and proteinuria detected.

Oxidative Stress-Induced Damage to RNA and DNA and Mortality in Individuals with Psychiatric Illness

Importance

All-cause mortality and the risk for age-related medical disease is increased in individuals with psychiatric illness, but the underlying biological mechanisms are not known. Oxidative stress on nucleic acids (DNA and RNA; NA-OXS) is a molecular driver of aging and a potential pathophysiological mechanism in a range of age-related disorders.

Objective

To study the levels of markers of NA-OXS in a large cohort of community-dwelling individuals with and without psychiatric illness and to evaluate their association with prospective all-cause mortality.

Design, Setting, and Participants

This cohort study used a combined cohort of participants from 2 population-based health studies: the Danish General Suburban Population Study (January 2010 to October 2013) and nondiabetic control participants from the Vejle Diabetes Biobank study (March 2007 to May 2010). Individual history of psychiatric illness was characterized using register data on psychiatric diagnoses and use of psychotropic drugs before baseline examination. Urinary markers of systemic RNA (8-oxo-7,8-dihydroguanosine [8-oxoGuo]) and DNA (8-oxo-7,8-dihydro-2'-deoxyguanosine [8-oxodG]) damage from oxidation were measured by ultraperformance liquid chromatography-tandem mass spectrometry. Cox proportional hazard regression models were applied for survival analyses, using register-based all-cause mortality updated to May 2023. The follow-up time was up to 16.0 years.

Exposures

History of psychiatric illness.

Main Outcomes and Measures

Mortality risk according to psychiatric illness status and 8-oxoGuo or 8-oxodG excretion level.

Results

A total of 7728 individuals were included (3983 [51.5%] female; mean [SD] age, 58.6 [11.9] years), 3095 of whom (40.0%) had a history of psychiatric illness. Mean (SD) baseline 8-oxoGuo was statistically significantly higher in individuals with psychiatric illness than in those without (2.4 [1.2] nmol/mmol vs 2.2 [0.9] nmol/mmol; P < .001), whereas 8-oxodG was not. All-cause mortality was higher in the psychiatric illness group vs the no psychiatric illness group (hazard ratio [HR], 1.44; 95% CI, 1.27-1.64; P < .001) and increased sequentially with each increasing tertile of 8-oxoGuo excretion in both groups to an almost doubled risk in the psychiatric illness/high 8-oxoGuo group compared to the no psychiatric illness/low 8-oxoGuo reference group (HR, 1.99; 95% CI, 1.58-2.52; P < .001). These results persisted after adjustment for a range of potential confounders and in a sensitivity analysis stratified for sex.

Conclusions and Relevance

This study establishes systemic oxidative stress-induced damage to RNA as a potential mechanism in the accelerated aging observed in psychiatric disorders and urinary 8-oxoGuo as a potentially useful marker of mortality risk in individuals with psychiatric illness.

Simvastatin-Mediated Nrf2 Activation Induces Fetal Hemoglobin and Antioxidant Enzyme Expression to Ameliorate the Phenotype of Sickle Cell Disease

Sickle cell disease (SCD) is a pathophysiological condition of chronic hemolysis, oxidative stress, and elevated inflammation. The transcription factor Nrf2 is a master regulator of oxidative stress. Here, we report that the FDA-approved oral agent simvastatin, an inhibitor of hydroxymethyl-glutaryl coenzyme A reductase, significantly activates the expression of Nrf2 and antioxidant enzymes. Simvastatin also induces fetal hemoglobin expression in SCD patient primary erythroid progenitors and a transgenic mouse model. Simvastatin alleviates SCD symptoms by decreasing hemoglobin S sickling, oxidative stress, and inflammatory stress in erythroblasts. Particularly, simvastatin increases cellular levels of cystine, the precursor for the biosynthesis of the antioxidant reduced glutathione, and decreases the iron content in SCD mouse spleen and liver tissues. Mechanistic studies suggest that simvastatin suppresses the expression of the critical histone methyltransferase enhancer of zeste homolog 2 to reduce both global and gene-specific histone H3 lysine 27 trimethylation. These chromatin structural changes promote the assembly of transcription complexes to fetal γ-globin and antioxidant gene regulatory regions in an antioxidant response element-dependent manner. In summary, our findings suggest that simvastatin activates fetal hemoglobin and antioxidant protein expression, modulates iron and cystine/reduced glutathione levels to improve the phenotype of SCD, and represents a therapeutic strategy for further development.

Circulating Metabolomic Associations with Neurocognitive Outcomes in Pediatric CKD

BACKGROUND

Children with CKD are at risk for impaired neurocognitive functioning. We investigated metabolomic associations with neurocognition in children with CKD.

METHODS

We leveraged data from the Chronic Kidney Disease in Children (CKiD) study and the Neurocognitive Assessment and Magnetic Resonance Imaging Analysis of Children and Young Adults with Chronic Kidney Disease (NiCK) study. CKiD is a multi-institutional cohort that enrolled children aged 6 months to 16 years with eGFR 30-90 ml/min per 1.73 m 2 ( n =569). NiCK is a single-center cross-sectional study of participants aged 8-25 years with eGFR<90 ml/min per 1.73 m 2 ( n =60) and matched healthy controls ( n =67). Untargeted metabolomic quantification was performed on plasma (CKiD, 622 metabolites) and serum (NiCK, 825 metabolites) samples. Four neurocognitive domains were assessed: intelligence, attention regulation, working memory, and parent ratings of executive function. Repeat assessments were performed in CKiD at 2-year intervals. Linear regression and linear mixed-effects regression analyses adjusting for age, sex, delivery history, hypertension, proteinuria, CKD duration, and glomerular versus nonglomerular diagnosis were used to identify metabolites associated with neurocognitive z-scores. Analyses were performed with and without adjustment for eGFR.

RESULTS

There were multiple metabolite associations with neurocognition observed in at least two of the analytic samples (CKiD baseline, CKiD follow-up, and NiCK CKD). Most of these metabolites were significantly elevated in children with CKD compared with healthy controls in NiCK. Notable signals included associations with parental ratings of executive function: phenylacetylglutamine, indoleacetylglutamine, and trimethylamine N-oxide-and with intelligence: γ -glutamyl amino acids and aconitate.

CONCLUSIONS

Several metabolites were associated with neurocognitive dysfunction in pediatric CKD, implicating gut microbiome-derived substances, mitochondrial dysfunction, and altered energy metabolism, circulating toxins, and redox homeostasis.

PODCAST

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Hypothyroid women have persistently higher oxidative stress compared to healthy controls

Objective

Some studies suggest that hypothyroidism is associated with increased oxidative stress. Urinary excretion of 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) represents whole-body RNA and DNA oxidation, respectively. These biomarkers have only been explored sparsely in patients with thyroid disorders.

Methods

In 45 Danish women with newly diagnosed hypothyroidism, we compared 8-oxoGuo and 8-oxodG before or shortly after initiating levothyroxine with the excretion rates at euthyroidism. We also compared the excretion of 8-oxoGuo and 8-oxodG in the patients after restored euthyroidism with 18 healthy control subjects.

Results

Compared with baseline, none of the biomarkers changed significantly in the patients after becoming euthyroid. The geometric mean of 8-oxoGuo was 1.63 (95% CI: 1.49-1.78) nmol/mmol creatinine at baseline and 1.67 nmol/mmol at euthyroidism (95% CI: 1.53-1.83) (P = 0.39), while that of 8-oxodG was 1.28 nmol/mmol creatinine at baseline (95% CI: 1.14-1.44) and 1.32 nmol/mmol at euthyroidism (95% CI: 1.18-1.48), respectively (P = 0.47). The relative mean differences were 0.97 (95% CI: 0.91-1.04) for 8-oxoGuo and 0.97 (95% CI: 0.88-1.06) for 8-oxodG. At baseline, multiple linear regression revealed a positive association between free thyroxine and both biomarkers (8-oxoGuo, P < 0.001; 8-oxodG, P = 0.04). Furthermore, 8-oxoGuo was positively associated with age (P = 0.04) and negatively associated with thyrotropin (P = 0.02). In the control group, the geometric mean of 8-oxoGuo was 1.23 nmol/mmol creatinine (95% CI: 1.07-1.42), while that of 8-oxodG was 1.04 nmol/mmol creatinine (95% CI: 0.88-1.23). Thus, compared with control subjects, euthyroid patients showed a significantly higher level of both 8-oxoGuo (P < 0.001) and 8-oxodG (P = 0.03).

Conclusion

In hypothyroid women, no significant effect of levothyroxine treatment on the oxidative stress biomarkers 8-oxoGuo and 8-oxodG could be demonstrated. However, the excretion of these biomarkers was significantly higher than in healthy controls.

Effects of different doses of exercise in adjunct to diet-induced weight loss on the AGE-RAGE axis in patients with short standing type 2 diabetes: Secondary analysis of the DOSE-EX multi-arm, parallel-group, randomised trial

AIMS/HYPOTHESIS

These secondary analyses aimed to investigate the effects of different volumes of exercise in adjunct to diet-induced weight loss and standard care on advanced glycation end-products (AGEs) and receptor for AGE (RAGE). We hypothesized that exercise in adjunct to a diet-induced weight loss would dose-dependently increase the soluble decoy receptor for AGE (sRAGE) more than diet-induced weight loss and standard care alone. Secondarily, we expected changes in sRAGE to be associated with improved glycaemic control and inversely associated with low-grade inflammation.

METHODS

The DOSE-EX study was a 16-week parallel-group, 4-arm, single-centre, assessor-blinded, randomised, controlled trial (NCT03769883). We included persons living with T2D, duration ≤7 years, BMI >27 kg/m2 and <40 kg/m2, without severe diabetic complications. Participants were randomised (1:1:1:1) to either 1) standard care as control (CON), 2) standard care + diet (DCON), 3) standard care + diet + moderate exercise dose (MED) or 4) standard care + diet + high exercise dose (HED). Standard care included algorithm-guided pharmacological treatment. The diet intervention aimed at 25% reduced energy intake. The supervised exercise sessions included two aerobic sessions + one combined (aerobic and resistance training) session per week for the MED group, and four aerobic sessions + two combined sessions per week for the HED group. Primary outcome was the change in sRAGE from baseline to 16-week follow-up. Secondary outcomes encompassed changes in advanced glycation endproducts (AGE), glycaemic control and markers of low-grade inflammation.

RESULTS

A total of 80 participants (CON: n = 20, DCON: n = 19, MED: n = 20, HED: n = 21) were included in this secondary analysis. The mean age was 58.3 years (SD 9.9), 53% males, and median T2D duration was 4.1 years (IQR 2.0-5.5). No change in sRAGE was observed in any of the groups from baseline to follow-up (p > 0.05).

CONCLUSION/INTERPRETATION

A 16-week intervention with either three or six exercise sessions per week in adjunct to diet-induced weight loss did not change the levels of sRAGE in persons living with well-regulated, short standing T2D.

Cerebrospinal fluid erythropoietin, oxidative stress, and cognitive functions in patients with bipolar disorder and healthy control participants: A longitudinal case-control study

Persistent cognitive impairments occur in a large proportion of patients with bipolar disorder (BD) but their underlying pathological cellular processes are unclear. The aims of this longitudinal study of BD and healthy control (HC) participants were to investigate (i) the association of brain erythropoietin (EPO) and oxidative stress with cognitive functions and (ii) the changes in brain EPO during and after affective episodes. Participants underwent neurocognitive testing, lumbar punctures for cerebrospinal fluid (CSF) sampling and provided urine spot tests at baseline (all), after an affective episode (patients) and after one year (all). EPO was assayed in the CSF and oxidative stress metabolites related to RNA and DNA damage (8-dihydroguanosine [8-oxo-Guo], 8-hydroxy-2-deoxyguanosine [8-oxo-dG]) were assayed in the CSF and spot urine. Data was available for analyses for 60 BD and 37 HC participants. In unadjusted primary analyses, verbal memory decreased with increasing concentrations of CSF EPO and oxidative stress. In unadjusted explorative analyses, poorer verbal memory and psychomotor speed were associated with higher levels of oxidative stress. However, no associations between cognitive functions and CSF levels of EPO or oxidative stress were observed after adjustment for multiple testing. CSF EPO concentrations were unchanged during and after affective episodes. While CSF EPO correlated negatively with CSF DNA damage marker 8-oxo-dG, this association rendered non-significant after adjusting for multiple testing. In conclusion, EPO and oxidative stress do not seem to be robustly related to cognitive status in BD. Further insight into the cellular processes involved in cognitive impairments in BD is necessary to pave the way for novel therapeutic strategies to improve patients' cognitive outcomes.

Specific prediction of mortality by oxidative stress-induced damage to RNA vs. DNA in humans

Modifications of nucleic acids (DNA and RNA) from oxidative stress is a potential driver of aging per se and of mortality in age-associated medical disorders such as type 2 diabetes (T2D). In a human cohort, we found a strong prediction of all-cause mortality by a marker of systemic oxidation of RNA in patients with T2D (n = 2672) and in nondiabetic control subjects (n = 4079). The finding persisted after the adjustment of established modifiers of oxidative stress (including BMI, smoking, and glycated hemoglobin). In contrast, systemic levels of DNA damage from oxidation, which traditionally has been causally linked to both T2D and aging, failed to predict mortality. Strikingly, these findings were subsequently replicated in an independent general population study (n = 3649). The data demonstrate a specific importance of RNA damage from oxidation in T2D and general aging.

Evaluation of the effects of metformin on antioxidant biomarkers and mineral levels in patients with type II diabetes mellitus: A cross-sectional study

Diabetes mellitus (DM) and arterial hypertension are considered serious public health problems. Several studies have shown that oxidative stress is usually related to the onset of DM and hypertension, as well their associated complications. Moreover, the levels of some minerals are closely related to the pathophysiology of these diseases. Thus, in this study we aimed to evaluate the effect of metformin on the redox profile and mineral levels in the serum of patients with DM type 2 and hypertension. We also tested the effect of metformin on the viability and redox profile of peripheral blood mononuclear cells (PBMCs) for 24 h. As expected, we found that patients with type 2 DM and hypertension + type 2 DM had higher fasting glucose and triglyceride levels. As groundbreaking research, we found that both patients DM type 2 and Hypertension + DM type 2 had reduced myeloperoxidase (MPO) activity. On the other hand, the levels of total thiols (PSH) and vitamin C were increased. There was no statistical significance for the alterations in mineral levels. In addition, metformin treatment had no cytotoxic effect on PBMCs. Similarly, in patients of both groups, MPO activity was reduced and PSH levels were increased in PBMCs. We have shown that metformin is a drug with a protective effect in patients with DM type 2 against oxidative stress by reducing MPO activity and improving the levels of PSH and antioxidant defenders such as vitamin C. The results of in vitro assays support the antioxidant effect of metformin. Furthermore, we suggest studies to assess the biochemical mechanisms of metformin and how it can be used in a pharmacological therapeutic perspective against oxidative damage.

Effects of Two- and Twelve-Weeks Sodium-Glucose Cotransporter 2 Inhibition on DNA and RNA Oxidation: Two Randomized, Placebo-Controlled Trials

Animal studies have shown that SGLT2 inhibition decreases oxidative stress, which may explain the cardiovascular protective effects observed following SGLT2 inhibition treatment. Thus, we investigated the effects of two and twelve weeks SGLT2 inhibition on DNA and RNA oxidation. Individuals with type 2 diabetes (n = 31) were randomized to two weeks of treatment with the SGLT2 inhibitor empagliflozin treatment (25 mg once daily) or placebo. The primary outcome was changes in DNA and RNA oxidation measured as urinary excretion of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo), respectively. In another trial, individuals with type 2 diabetes (n = 35) were randomized to twelve weeks of dapagliflozin treatment (10 mg once daily) or placebo in a crossover study. Changes in urinary excretion of 8-oxodG and 8-oxoGuo were investigated as a post-hoc analysis. Compared with placebo treatment, two weeks of empagliflozin treatment did not change urinary excretion of 8-oxodG (between-group difference: 0.3 nmol/24-hour (95% CI: -4.2 to 4.8)) or 8-oxoGuo (1.3 nmol/24-hour (95% CI: -4.7 to 7.3)). From a mean baseline 8-oxodG/creatinine urinary excretion of 1.34 nmol/mmol, dapagliflozin-treated individuals changed 8-oxodG/creatinine by -0.17 nmol/mmol (95% CI: -0.29 to -0.04) following twelve weeks of treatment, whereas placebo-treated individuals did not change 8-oxodG/creatinine (within-group effect: 0.10 nmol/mmol (95% CI: -0.02 to 0.22)) resulting in a significant between-group difference (P = 0.01). Urinary excretion of 8-oxoGuo was unaffected by dapagliflozin treatment. In conclusion, two weeks of empagliflozin treatment did not change DNA or RNA oxidation. However, a post-hoc analysis revealed that longer term dapagliflozin treatment decreased DNA oxidation. Clinicaltrials.gov: NCT02890745 and NCT02914691.HighlightsPlasma ferritin correlated with DNA and RNA oxidation in individuals with T2DTwelve weeks dapagliflozin treatment decreased DNA oxidationDapagliflozin and empagliflozin treatment did not change RNA oxidationLipid peroxidation was unaffected by two weeks empagliflozin treatment.

Oxidative Stress and Cardiovascular Risk Factors: The Coronary Artery Risk Development in Young Adults (CARDIA) Study

Introduction—Oxidative stress is linked to cardiovascular diseases (CVD) and is suggested to vary by sex. However, few population-level studies have explored these associations and the majority comprise populations with advanced CVD. We assessed urinary isoprostane concentrations, a standard measure of oxidative stress, in a relatively young and healthy cohort, hypothesizing that higher oxidative stress is associated with an adverse cardiometabolic profile and female sex. Methods—Oxidative stress was measured in 475 women and 266 men, aged 48–55 years, from the Coronary Artery Risk Development in Young Adults (CARDIA) study using urinary 8-isoprostane (IsoP) and 2,3-dinor-8-isoprostane (IsoP-M). Multivariable-adjusted regression was used to evaluate cross-sectional associations. As secondary analysis, previously measured plasma F2-isoprostanes (plasma IsoP) from another CARDIA subset was similarly analyzed. Results—Mean (SD) ages for men and women were 52.1(2.3) and 52.2(2.2) years, respectively (p = 0.46), and 39% of the participants self-identified as Black (vs. White). Before adjustments, female sex was associated with higher median urinary IsoP (880 vs. 704 ng/g creatinine in men; p < 0.01) and IsoP m (1675 vs. 1284 ng/g creatinine in men; p < 0.01). Higher body mass index (BMI), high-density cholesterol (HDL-C), and triglycerides, current smoking, and less physical activity were associated with higher oxidative stress. Diabetes was not associated with urinary IsoP but was associated with lower IsoP m and plasma IsoP. Higher serum creatinine showed diverging associations with higher plasma and lower urinary isoprostane concentrations. Conclusions—Different isoprostane entities exhibit varying association patterns with CVD risk factors, and therefore are complementary, rather than interchangeable, in assessment of oxidative stress. Still, consistently higher isoprostanes among women, smokers, less active persons, and those with higher BMI and plasma triglycerides could reflect higher oxidative stress among these groups. While urinary isoprostanes are indexed to urinary creatinine due to variations in concentration, caution should be exercised when comparing groups with differing serum creatinine.

Donor Simvastatin Treatment Is Safe and Might Improve Outcomes After Liver Transplantation: A Randomized Clinical Trial

BACKGROUND

The current curative approaches for ischemia/reperfusion injury on liver transplantation are still under debate for their safety and efficacy in patients with end-stage liver disease. We present the SIMVA statin donor treatment before Liver Transplants study.

METHODS

SIMVA statin donor treatment before Liver Transplants is a monocentric, double-blind, randomized, prospective tial aiming to compare the safety and efficacy of preoperative brain-dead donors' treatment with the intragastric administration of 80 mg of simvastatin on liver transplant recipient outcomes in a real-life setting. Primary aim was incidence of patient and graft survival at 90 and 180 d posttransplant; secondary end-points were severe complications.

RESULTS

The trial enrolled 58 adult patients (18-65 y old). The minimum follow-up was 6 mo. No patient or graft was lost at 90 or 180 d in the experimental group (n = 28), whereas patient/graft survival were 93.1% ( P = 0.016) and 89.66% ( P = 0.080) at 90 d and 86.21% ( P = 0.041) and 86.2% ( P = 0.041) at 180 d in the control group (n = 29). The percentage of patients with severe complications (Clavien-Dindo ≥IIIb) was higher in the control group, 55.2% versus 25.0% in the experimental group ( P = 0.0307). The only significant difference in liver tests was a significantly higher gamma-glutamyl transferase and alkaline phosphatase at 15 d ( P = 0.017), ( P = 0.015) in the simvastatin group.

CONCLUSIONS

Donor simvastatin treatment is safe, and may significantly improve early graft and patient survival after liver transplantation, although further research is mandatory.

Simvastatin is Efficacious in Treating Cirrhosis: A Meta-analysis

BACKGROUND

Statins can improve prognosis of patients with liver cirrhosis by suppressing inflammation and lowering portal pressure. Here, we performed a meta-analysis to evaluate the clinical efficacy of simvastatin in liver cirrhosis patients.

METHODS

We searched PubMed, EMBASE, and Cochrane library databases for randomized controlled trials targeting simvastatin in patients with liver cirrhosis. The primary and secondary outcomes were the efficacy of simvastatin on clinical outcomes and its safety, respectively.

RESULTS

A total of 554 relevant articles were downloaded, of which 9 (comprising 648 participants) were eligible and were finally included in the analysis. Four studies revealed the impact of simvastatin on patient mortality, with the overall death rate found to be significantly lower in the simvastatin relative to the control group [risk ratio (RR): 0.46; 95% confidence interval (CI), 0.29 to 0.73; P <0.01]. Further analysis of the cause of death showed that simvastatin significantly reduces incidence of fatal bleeding (RR: 0.35; 95% CI, 0.13 to 0.95; P =0.04), as well as cholesterol [mean difference (MD): -31.48; 95% CI, -52.80 to -10.15; P <0.01] and triglyceride (MD: -25.88; 95% CI, -49.90 to -1.86; P =0.03) levels. At the same time, simvastatin did not significantly elevate levels of alanine aminotransferase (ALT) (MD: 2.34; 95% CI, -31.00 to 35.69; P =0.89) and was not associated with incidence of other side effects.

CONCLUSIONS

The use of simvastatin in cirrhotic patients lowers mortality rates by suppressing incidences of fatal bleeding.

Effects of an exercise-based lifestyle intervention on systemic markers of oxidative stress and advanced glycation endproducts in persons with type 2 diabetes: Secondary analysis of a randomised clinical trial

AIMS/HYPOTHESIS

This secondary analysis aimed to investigate the effects of a 12 months intensive exercise-based lifestyle intervention on systemic markers of oxidative stress in persons with type 2 diabetes. We hypothesized lifestyle intervention to be superior to standard care in decreasing levels of oxidative stress.

METHODS

The study was based on the single-centre, assessor-blinded, randomised, controlled U-turn trial (ClinicalTrial.gov NCT02417012). Persons with type 2 diabetes ˂ 10 years, ˂ 3 glucose lowering medications, no use of insulin, BMI 25-40 kg/m² and no severe diabetic complications were included. Participants were randomised (2:1) to either intensive exercise-based lifestyle intervention and standard (n = 64) or standard care alone (n = 34). Standard care included individual education in diabetes management, advice on a healthy lifestyle and regulation of medication by a blinded endocrinologist. The lifestyle intervention included five to six aerobic exercise sessions per week, combined with resistance training two to three times per week and an adjunct dietary intervention aiming at reduction of ∼500 kcal/day (month 0-4). The diet was isocaloric from months 5-12. The primary outcome of this secondary analysis was change in oxidative stress measured by 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and secondarily in 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), as markers of RNA and DNA oxidation, respectively, from baseline to 12-months follow-up.

RESULTS

A total of 77 participants, 21 participants receiving standard care and 56 participants receiving the lifestyle intervention, were included in the analysis. Mean age at baseline was 54.1 years (SD 9.1), 41% were women and mean duration of type 2 diabetes was 5.0 years (SD 2.8). From baseline to follow-up the lifestyle group experienced a 7% decrease in 8-oxoGuo (-0.15 nmol/mmol creatinine [95% CI -0.27, -0.03]), whereas standard care conversely was associated with a 8.5% increase in 8-oxoGuo (0.19 nmol/mmol creatinine [95% CI 0.00, 0.40]). The between group difference in 8-oxoGuo was -0.35 nmol/mmol creatinine [95% CI -0.58, -0.12,], p = 0.003. No between group difference was observed in 8-oxodG.

CONCLUSION/INTERPRETATION

A 12 months intensive exercise-based lifestyle intervention was associated with a decrease in RNA, but not DNA, oxidation in persons with type 2 diabetes.

Effects of 2-Year Nutritional and Lifestyle Intervention on Oxidative and Inflammatory Statuses in Individuals of 55 Years of Age and over at High Cardiovascular Risk

Obesity and overweight are disorders with high impact on the morbidity and mortality of chronic diseases, such as type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD). We aim to assess the effects of 2-year nutritional and lifestyle intervention on oxidative and inflammatory status in individuals of 55 years of age and over at high CVD risk. Participants (n = 100 individuals of 55 years of age and over living in the Balearic Islands, Spain) were randomized into control and intervention group. Anthropometric and haematological parameters, blood pressure and physical activity were measured before and after the intervention. Oxidative and inflammatory biomarkers in plasma, urine, peripheral blood mononuclear cells (PBMCs) and neutrophils were determined. A higher reduction in abdominal obesity, blood pressure and triglycerides levels was observed after a 2-year intervention. An improvement of oxidative stress and proinflammatory status was demonstrated with a significant reduction in myeloperoxidase, xanthine oxidase, malondialdehyde and monocyte chemoattractant protein-1 (MCP1) levels, and an increase in polyphenols in plasma was observed. A decrease in reactive oxygen species production in PBMCs and neutrophils levels after zymosan and lipopolysaccharide activation was found in the intervention group with respect to the control group. The intervention with hypocaloric Mediterranean Diet and customized physical activity improves oxidative stress and proinflammatory status and could contribute to decreasing the CVD risk.

Simvastatin as an emerging pollutant on non-target aquatic invertebrates: effects on antioxidant-related genes in Daphnia magna

Simvastatin (SIM) is one of the most widely used lipid-lowering drugs and consequently has been frequently detected in various waters. However, its potential adverse effects and toxic mechanisms on non-target organisms such as Daphnia magna (D. magna) remain still unclear. In the present study, the expressions of Nrf2 and antioxidant genes including Keap1, HO-1, GCLC, GST, SOD, CAT, GPx5, GPx7, GRx, TRX, TrxR, and Prx1 in D. magna exposed to SIM for 24 h, 48 h, and 96 h were investigated. The changes of SOD, CAT, GST, and GPx enzymatic activities, and the GSH and MDA content under SIM for 48-h exposure were also addressed. Results showed that the expression of Nrf2 was inhibited at 24 h but induced at 96 h, displaying a time- and/or dose-dependent relationship under SIM exposure. In contrast, Keap1 exhibited induction at 24 h. HO-1 showed significant induction under SIM exposure for different time. SOD generally displayed an induction trend under SIM exposure for different periods. GPX5 expression showed significant induction under SIM exposure, particularly at 24 h in 5 µg L^-1 increasing 15 folds of the control. But GPX7 expression generally displayed inhibition except in 5 µg L^-1. Trx and TrxR showed different induction or inhibition, which was depended on the exposure time and concentration. Prx1 displayed significant induction in most SIM groups. In addition, the decreasing GSH and increasing MDA content also indicated oxidative stress of SIM exposure. Overall, SIM exposure affected the expression of Nrf2 and antioxidant-related genes and altered the redox homeostasis of D. magna, even may cause the morphological changes such as shorten spine and abnormal development eye.

Systemic DNA and RNA damage from oxidation after serotonergic treatment of unipolar depression

Previous studies have indicated that antidepressants that inhibit the serotonin transporter reduces oxidative stress. DNA and RNA damage from oxidation is involved in aging and a range of age-related pathophysiological processes. Here, we studied the urinary excretion of markers of DNA and RNA damage from oxidation, 8-oxodG and 8-oxoGuo, respectively, in the NeuroPharm cohort of 100 drug-free patients with unipolar depression and in 856 non-psychiatric community controls. Patients were subsequently treated for 8 weeks with escitalopram in flexible doses of 5-20 mg; seven of these switched to duloxetine by week 4, as allowed by the protocol. At week 8, 82 patients were followed up clinically and with measurements of 8-oxodG/8-oxoGuo. Contextual data were collected in patients, including markers of cortisol excretion and low-grade inflammation. The intervention was associated with a substantial reduction in both 8-oxodG/8-oxoGuo excretion (25% and 10%, respectively). The change was not significantly correlated to measures of clinical improvement. Both markers were strongly and negatively correlated to cortisol, as measured by the area under the curve for the full-day salivary cortisol excretion. Surprisingly, patients had similar levels of 8-oxodG excretion and lower levels of 8-oxoGuo excretion at baseline compared to the controls. We conclude that intervention with serotonin reuptake inhibitors in unipolar depression is associated with a reduction in systemic DNA and RNA damage from oxidation. To our knowledge, this to date the largest intervention study to characterize this phenomenon, and the first to include a marker of RNA oxidation.

Associations of urinary metabolites of oxidized DNA and RNA with the incidence of diabetes mellitus using UPLC-MS/MS and ELISA methods

BACKGROUND

To evaluate the association of urinary oxidized guanine/guanosine (OxGuo) levels with incident type 2 diabetes (T2D) among older adults.

METHODS

A nested case-control design was applied with 440 cases of incident T2D and 440 controls, randomly sampled from all 65-75 year-old study participants of the ESTHER study, which is a population-based German cohort study with 14 years of follow-up. Analyses of 8-hydroxy-2'-deoxyguanosine (8-oxo-dGuo; DNA oxidation product) and 8-hydroxyguanosine (8-oxo-Guo; RNA oxidation product) were measured by ultra-performance liquid chromatography tandem-mass spectrometry (UPLC-MS/MS). The sum of the two OxGuo molecule concentrations was calculated and called OxGuo-UPLC-MS/MS. The corresponding OxGuo-ELISA levels were measured by Cayman's DNA/RNA oxidative damage ELISA, which detects a mix of 8-oxo-dGuo, 8-oxo-Guo and one other OxGuo molecule. Logistic regression was applied and models were adjusted for age, sex, BMI, HbA_1c, and C-reactive protein levels.

RESULTS

8-oxo-dGuo and 8-oxo-Guo were highly correlated with each other (r = 0.642) and weakly correlated with OxGuo-ELISA (r = 0.22 and r = 0.14, respectively). OxGuo-ELISA levels were statistically significant associated with T2D incidence (odds ratio (OR) and 95% confidence interval [95%CI] for comparison of top and bottom quartile: 1.77 [1.14; 2.76]). In contrast, the ORs did not increase stepwise from quartile 2 to 4 for neither 8-oxo-Guo, 8-oxo-dGuo levels nor OxGuo-UPLC-MS/MS and comparisons of top and bottom quartile were not statistically significant. In a post-hoc analysis comparing bottom quartile 1 with a combined group of quartile 2-4, the association of OxGuo-UPLC-MS/MS with T2D incidence reached statistical significance (OR [95%CI]: 0.66 [0.46; 0.96]) and was very similar with the one obtained for OxGuo-ELISA (OR [95%CI]: 0.66 [0.45; 0.95]).

CONCLUSIONS

Although only the measurements of the DNA/RNA oxidative damage ELISA kit of Cayman were statistically significantly associated with T2D incidence in the main analysis, confidence intervals overlapped and the post-hoc analysis showed that results for OxGuo-UPLC-MS/MS were quite comparable.

Effects of 18-months metformin versus placebo in combination with three insulin regimens on RNA and DNA oxidation in individuals with type 2 diabetes: A post-hoc analysis of a randomized clinical trial

Formation of reactive oxygen species has been linked to the development of diabetes complications. Treatment with metformin has been associated with a lower risk of developing diabetes complications, including when used in combination with insulin. Metformin inhibits Complex 1 in isolated mitochondria and thereby decreases the formation of reactive oxygen species. Thus, we post-hoc investigated the effect of metformin in combination with different insulin regimens on RNA and DNA oxidation in individuals with type 2 diabetes. Four hundred and fifteen individuals with type 2 diabetes were randomized (1:1) to blinded treatment with metformin (1,000 mg twice daily) versus placebo and to (1:1:1) open-label biphasic insulin, basal-bolus insulin, or basal insulin therapy in a 2 × 3 factorial design. RNA and DNA oxidation were determined at baseline and after 18 months measured as urinary excretions of 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), respectively. Urinary excretion of 8-oxoGuo changed by +7.1% (95% CI: 0.5% to 14.0%, P = 0.03) following metformin versus placebo, whereas changes in 8-oxodG were comparable between intervention groups. Biphasic insulin decreased urinary excretion of 8-oxoGuo (within-group: -9.6% (95% CI: -14.4% to -4.4%)) more than basal-bolus insulin (within-group: 5.2% (95% CI: -0.5% to 11.2%)), P = 0.0002 between groups, and basal insulin (within-group: 3.7% (95% CI: -2.0% to 9.7%)), P = 0.0007 between groups. Urinary excretion of 8-oxodG decreased more in the biphasic insulin group (within-group: -9.9% (95% CI: -14.4% to -5.2%)) than basal-bolus insulin (within group effect: -1.2% (95% CI: -6.1% to 3.9%)), P = 0.01 between groups, whereas no difference was observed compared with basal insulin. In conclusion, eighteen months of metformin treatment in addition to different insulin regimens increased RNA oxidation, but not DNA oxidation. Biphasic insulin decreased both RNA and DNA oxidation compared with other insulin regimens.

Skeletal muscle adaptations to exercise are not influenced by metformin treatment in humans: secondary analyses of two randomised, clinical trials

Metformin and exercise both improve glycemic control, but in vitro studies have indicated that an interaction between metformin and exercise occurs in skeletal muscle, suggesting a blunting effect of metformin on exercise training adaptations. Two studies (a double-blind, parallel-group, randomized clinical trial conducted in 29 glucose-intolerant individuals and a double-blind, cross-over trial conducted in 15 healthy lean males) were included in this paper. In both studies, the effect of acute exercise +/- metformin treatment on different skeletal muscle variables, previously suggested to be involved in a pharmaco-physiological interaction between metformin and exercise, was assessed. Furthermore, in the parallel-group trial, the effect of 12 weeks of exercise training was assessed. Skeletal muscle biopsies were obtained before and after acute exercise and 12 weeks of exercise training, and mitochondrial respiration, oxidative stress and AMPK activation was determined. Metformin did not significantly affect the effects of acute exercise or exercise training on mitochondrial respiration, oxidative stress or AMPK activation, indicating that the response to acute exercise and exercise training adaptations in skeletal muscle is not affected by metformin treatment. Further studies are needed to investigate whether an interaction between metformin and exercise is present in other tissues, e.g. the gut. Trial registration: ClinicalTrials.gov (NCT03316690 and NCT02951260). Novelty bullets • Metformin does not affect exercise-induced alterations in mitochondrial respiratory capacity in human skeletal muscle • Metformin does not affect exercise-induced alterations in systemic levels of oxidative stress nor emission of reactive oxygen species from human skeletal muscle • Metformin does not affect exercise-induced AMPK activation in human skeletal muscle.

Quantification of 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydro-guanosine concentrations in urine and plasma for estimating 24-h urinary output

Among markers for oxidative stress urinary excretion 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) and 8-oxo-7,8-dihydro-guanosine (8-oxoGuo) have been widely used in controlled and epidemiological studies, and are considered to represent intracellular markers of oxidation of DNA and RNA in the entire organism, respectively. Although being non-invasive, urinary methods have shortcomings. There is no established method for analysis of 8-oxodGuo and 8-oxoGuo in plasma and the few plasma values presented in the literature vary greatly. We here present a liquid chromatography mass spectrometry method with full validation for analysis of 8-oxodGuo and 8-oxoGuo in plasma. Further, we investigated the basis for our previously physiological model and show that a single plasma sample can be used to estimate the 24-h production of 8-oxoGuo, whereas we challenge the use of urinary 8-oxodGuo/creatinine ratio or plasma 8-oxodGuo as measures of oxidative stress.

Therapeutic advancement of simvastatin-loaded solid lipid nanoparticles (SV-SLNs) in treatment of hyperlipidemia and attenuating hepatotoxicity, myopathy and apoptosis: Comprehensive study

This study set out to optimize simvastatin (SV) in lipid nanoparticles (SLNs) to improve bioavailability, efficacy and alleviate adverse effects. Simvastatin-loaded solid lipid nanoparticles (SV-SLNs) were prepared by hot-melt ultrasonication method and optimized by box-Behnken experimental design. Sixty Wister albino rats were randomly assigned into six groups and treated daily for 16 weeks: control group, the group fed with 20 g of high-fat diet (HFD), group treated with vehicle (20 mg/kg, P.O.) for last four weeks, group treated with HFD and SV (20 mg/kg, P.O.) / or SV-SLNs (20 mg/kg/day, P.O.) / or SV-SLNs (5 mg/kg, P.O.) at last four weeks. Blood, liver tissues, and quadriceps muscles were collected for biochemical analysis, histological and immunohistochemical assays. The optimized SV-SLNS showed a particle-size 255.2 ± 7.7 nm, PDI 0.31 ± 0.09, Zeta-potential - 19.30 ± 3.25, and EE% 89.81 ± 2.1%. HFD showed severe changes in body weight liver functions, lipid profiles, atherogenic index (AIX), albumin, glucose, insulin level, alkaline phosphatase as well as muscle injury, oxidative stress biomarkers, and protein expression of caspase-3. Simvastatin treatment in animals feed with HFD showed a significant improvement of all tested parameters, but it was associated with hepatotoxicity, myopathy, and histological changes in quadriceps muscles. SV-SLNs exhibited a significant improvement of all biochemical, histological examinations, and immunohistochemical assays. SV-SLNs (5 mg/kg) treatment returns all measured parameters to control itself. These results represent that SV-SLNs is a promising candidate as a drug carrier for delivering SV with maximum efficacy and limited adverse reaction.

Treatment of Hyperthyroidism Reduces Systemic Oxidative Stress, as Measured by Markers of RNA and DNA Damage

BACKGROUND

Whole-body oxidative stress can be estimated by the urine excretion of oxidized guanosine species, 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), derived from RNA and DNA, respectively. These oxidative stress markers are not well explored in thyroid disorders.

OBJECTIVE

We aimed to determine whether treatment of hyperthyroid patients affects the levels of these oxidative stress markers.

METHODS

Urinary excretion of 8-oxoGuo and 8-oxodG was measured in 51 hyperthyroid patients (toxic nodular goiter [TNG], n = 30; Graves disease [GD], n = 21) before or shortly after initiation of therapy and when stable euthyroidism had been achieved for at least 12 months.

RESULTS

Adjusting for age, the baseline urinary excretion of oxidative stress markers correlated positively with plasma thyroxine (8-oxoGuo, P = 0.002; 8-oxodG, P = 0.021) and was significantly higher in GD than in TNG patients (P = 0.001 for both oxidative stress markers). Restoration of euthyroidism significantly affected the excretion of the oxidative stress markers. In TNG, 8-oxoGuo decreased from geometric mean 2.11 nmol/mmol creatinine (95% CI, 1.85-2.39) to 1.91 nmol/mmol (95% CI, 1.67-2.19; P = 0.001), while 8-oxodG decreased from 1.65 nmol/mmol (95% CI, 1.41-1.93) to 1.48 nmol/mmol (95% CI, 1.27-1.74; P = 0.026). In GD, 8-oxoGuo decreased from 2.25 nmol/mmol (95% CI, 1.95-2.59) to 1.79 nmol/mmol (95% CI, 1.63-1.97; P = 0.0003), while 8-oxodG decreased from 2.02 nmol/mmol (95% CI, 1.73-2.38) to 1.54 nmol/mmol (95% CI, 1.31-1.81; P = 0.001). In the euthyroid state, there were no differences between groups.

CONCLUSION

Restoration of euthyroidism in patients with hyperthyroidism significantly decreased the systemic oxidative stress load by 10% to 25%. Our findings may help to explain the higher morbidity and mortality linked to hyperthyroid diseases, as shown in observational studies.

The effect of liraglutide and sitagliptin on oxidative stress in persons with type 2 diabetes

Glucagon-like peptide 1 receptor agonists have shown cardioprotective effects which have been suggested to be mediated through inhibition of oxidative stress. We investigated the effect of treatment with a glucagon-like peptide 1 receptor agonist (liraglutide) on oxidative stress measured as urinary nucleic acid oxidation in persons with type 2 diabetes. Post-hoc analysis of two independent, randomised, placebo-controlled and double-blinded clinical trials. In a cross-over study where persons with type 2 diabetes and microalbuminuria (LIRALBU, n = 32) received liraglutide (1.8 mg/day) or placebo for 12 weeks in random order, separated by 4 weeks of wash-out. In a parallel-grouped study where obese persons with type 2 diabetes (SAFEGUARD, n = 56) received liraglutide (1.8 mg/day), sitagliptin (100 mg/day) or placebo for 12 weeks. Endpoints were changes in the urinary markers of DNA oxidation (8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG)) and RNA oxidation [8-oxo-7,8-dihydroguanosine (8-oxoGuo)]. In LIRALBU, we observed no significant differences between treatment periods in urinary excretion of 8-oxodG [0.028 (standard error (SE): 0.17] nmol/mmol creatinine, p = 0.87) or of 8-oxoGuo [0.12 (0.12) nmol/mmol creatinine, p = 0.31]. In SAFEGUARD, excretion of 8-oxodG was not changed in the liraglutide group [2.8 (− 8.51; 15.49) %, p = 0.62] but a significant decline was demonstrated in the placebo group [12.6 (− 21.3; 3.1) %, p = 0.02], resulting in a relative increase in the liraglutide group compared to placebo (0.16 nmol/mmol creatinine, SE 0.07, p = 0.02). Treatment with sitagliptin compared to placebo demonstrated no significant difference (0.07 (0.07) nmol/mmol creatinine, p = 0.34). Nor were any significant differences for urinary excretion of 8-oxoGuo liraglutide vs placebo [0.09 (SE: 0.07) nmol/mmol creatinine, p = 0.19] or sitagliptin vs placebo [0.07 (SE: 0.07) nmol/mmol creatinine, p = 0.35] observed. This post-hoc analysis could not demonstrate a beneficial effect of 12 weeks of treatment with liraglutide or sitagliptin on oxidatively generated modifications of nucleic acid in persons with type 2 diabetes.

The effects of different doses of exercise on pancreatic β-cell function in patients with newly diagnosed type 2 diabetes: study protocol for and rationale behind the "DOSE-EX" multi-arm parallel-group randomised clinical trial

BACKGROUND

Lifestyle intervention, i.e. diet and physical activity, forms the basis for care of type 2 diabetes (T2D). The current physical activity recommendation for T2D is aerobic training for 150 min/week of moderate to vigorous intensity, supplemented with resistance training 2-3 days/week, with no more than two consecutive days without physical activity. The rationale for the recommendations is based on studies showing a reduction in glycated haemoglobin (HbA1c). This reduction is supposed to be caused by increased insulin sensitivity in muscle and adipose tissue, whereas knowledge about effects on abnormalities in the liver and pancreas are scarce, with the majority of evidence stemming from in vitro and animal studies. The aim of this study is to investigate the role of the volume of exercise training as an adjunct to dietary therapy in order to improve the pancreatic β-cell function in T2D patients less than 7 years from diagnosis. The objective of this protocol for the DOSE-EX trial is to describe the scientific rationale in detail and to provide explicit information about study procedures and planned analyses.

METHODS/DESIGN

In a parallel-group, 4-arm assessor-blinded randomised clinical trial, 80 patients with T2D will be randomly allocated (1:1:1:1, stratified by sex) to 16 weeks in either of the following groups: (1) no intervention (CON), (2) dietary intervention (DCON), (3) dietary intervention and supervised moderate volume exercise (MED), or (4) dietary intervention and supervised high volume exercise (HED). Enrolment was initiated December 15th, 2018, and will continue until N = 80 or December 1st, 2021. Primary outcome is pancreatic beta-cell function assessed as change in late-phase disposition index (DI) from baseline to follow-up assessed by hyperglycaemic clamp. Secondary outcomes include measures of cardiometabolic risk factors and the effect on subsequent complications related to T2D. The study was approved by The Scientific Ethical Committee at the Capital Region of Denmark (H-18038298).

TRIAL REGISTRATION

The Effects of Different Doses of Exercise on Pancreatic β-cell Function in Patients With Newly Diagnosed Type 2 Diabetes (DOSE-EX), NCT03769883, registered 10 December 2018 https://clinicaltrials.gov/ct2/show/NCT03769883 ). Any modification to the protocol, study design, and changes in written participant information will be approved by The Scientific Ethical Committee at the Capital Region of Denmark before effectuation.

DISCUSSION

The data from this study will add knowledge to which volume of exercise training in combination with a dietary intervention is needed to improve β-cell function in T2D. Secondarily, our results will elucidate mechanisms of physical activity mitigating the development of micro- and macrovascular complications correlated with T2D.

The effects of 3 weeks of oral glutathione supplementation on whole body insulin sensitivity in obese males with and without type 2 diabetes: a randomized trial

The effect of oral glutathione (GSH) supplementation was studied in obese subjects with and without type 2 diabetes (T2DM) on measures of glucose homeostasis and markers of oxidative stress. Twenty subjects (10 patients with T2DM and 10 obese subjects) were recruited for the study, and randomized in a double-blinded placebo-controlled manner to consume either 1000 mg GSH per day or placebo for 3 weeks. Before and after the 3 weeks insulin sensitivity was measured with the hyperinsulinemic-euglycemic clamp and a muscle biopsy was obtained to measure GSH and skeletal muscle mitochondrial hydrogen peroxide (H₂O₂) emission rate. Whole body insulin sensitivity increased significantly in the GSH group. Skeletal muscle GSH was numerically increased (∼19%) in the GSH group; no change was seen in GSH to glutathione disulfide ratio. Skeletal muscle mitochondrial H₂O₂ emission rate did not change in response to the intervention and neither did the urinary excretion of the RNA oxidation product 8-oxo-7,8-dihydroguanosine or the DNA oxidation product 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), although 8-oxodG decreased as a main effect of time. Oral GSH supplementation improves insulin sensitivity in obese subjects with and without T2DM, although it does not alter markers of oxidative stress. The study has been registered in clinicaltrials.gov (NCT02948673). Novelty: Reduced glutathione supplementation increases insulin sensitivity in obese subjects with and without T2DM. H₂O₂ emission rate from skeletal muscle mitochondria was not affected by GSH supplementation.

Elevated levels of oxidized nucleosides in individuals with the JAK2V617F mutation from a general population study

It is unknown if the somatic mutations in chronic myeloproliferative neoplasms (MPNs), JAK2V617F and Calreticulin, are associated with oxidative stress, or impaired mitochondrial defense against reactive oxygen species. In the Danish General Suburban Population Study (GESUS), including 116 JAK2V617F-mutated, 8 CALR-mutated, and 3310 mutation-negative participants without overt MPN, and in a study of 39 patients with myelofibrosis, the most advances type of MPNs, and 179 matched controls, we compared the urinary concentration of oxidized nucleosides – 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo) – as markers of oxidative stress. In GESUS, we performed Mendelian randomization analyses, using the Ala16Val single nucleotide polymorphism in the superoxide dismutase2 (SOD2) gene. In the multivariate analyses in GESUS, the 8-oxodG and 8-oxoGuo concentration were 13% (95%CI: 6–21%, p < 0.001) and 6% (95%CI: 0.4–11%, p = 0.035) higher in mutation-positive than in mutation-negative participants, respectively. Each SOD2 T allele was associated with an odds ratio of being mutation-positive of 1.69 (95%CI: 1.12–2.55, p = 0.013) through 8-oxodG. The 8-oxodG and 8-oxoGuo concentrations were 77% (95%CI: 49–110%, p < 0.001) and 105% (95%CI: 80–133%, p < 0.001) higher in myelofibrosis patients than in controls, respectively. In conclusion, an impaired mitochondrial antioxidative defense, that is causatively associated with markers of oxidative stress, may contribute to the development of mutations associated with MPNs.

Reduction of oxidative stress on DNA and RNA in obese patients after Roux-en-Y gastric bypass surgery-An observational cohort study of changes in urinary markers

Increased oxidative stress in obesity and diabetes is associated with morbidity and mortality risks. Levels of oxidative damage to DNA and RNA can be estimated through measurement of 8-oxo-7,8-dihydro-2´-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo) in urine. Both markers have been associated with type 2 diabetes, where especially 8-oxoGuo is prognostic for mortality risk. We hypothesized that Roux-en-Y gastric bypass (RYGB) surgery that has considerable effects on bodyweight, hyperglycemia and mortality, might be working through mechanisms that reduce oxidative stress, thereby reducing levels of the urinary markers. We used liquid chromatography coupled with tandem mass spectrometry to analyze the content of 8-oxodG and 8-oxoGuo in urinary samples from 356 obese patients treated with the RYGB-procedure. Mean age (SD) was 44.2 (9.6) years, BMI was 42.1 (5.6) kg/m2. Ninety-six (27%) of the patients had type 2 diabetes. Excretion levels of each marker before and after surgery were compared as estimates of the total 24-hour excretion, using a model based on glomerular filtration rate (calculated from cystatin C, age, height and weight), plasma- and urinary creatinine. The excretion of 8-oxodG increased in the first months after RYGB. For 8-oxoGuo, a gradual decrease was seen. Two years after RYGB and a mean weight loss of 35 kg, decreased hyperglycemia and insulin resistance, excretion levels of both markers were reduced by approximately 12% (P < 0.001). For both markers, mean excretion levels were about 30% lower in the female subgroup (P < 0.0001). Also, in this subgroup, excretion of 8-oxodG was significantly lower in patients with than without diabetes. We conclude, that oxidative damage to nucleic acids, reflected in the excretion of 8-oxodG and 8-oxoGuo, had decreased significantly two years after RYGB-indicating that reduced oxidative stress could be contributing to the many long-term benefits of RYGB-surgery in obesity and type 2 diabetes.

Endothelial dysfunction in neuroprogressive disorders-causes and suggested treatments

BACKGROUND

Potential routes whereby systemic inflammation, oxidative stress and mitochondrial dysfunction may drive the development of endothelial dysfunction and atherosclerosis, even in an environment of low cholesterol, are examined.

MAIN TEXT

Key molecular players involved in the regulation of endothelial cell function are described, including PECAM-1, VE-cadherin, VEGFRs, SFK, Rho GEF TRIO, RAC-1, ITAM, SHP-2, MAPK/ERK, STAT-3, NF-κB, PI3K/AKT, eNOS, nitric oxide, miRNAs, KLF-4 and KLF-2. The key roles of platelet activation, xanthene oxidase and myeloperoxidase in the genesis of endothelial cell dysfunction and activation are detailed. The following roles of circulating reactive oxygen species (ROS), reactive nitrogen species and pro-inflammatory cytokines in the development of endothelial cell dysfunction are then described: paracrine signalling by circulating hydrogen peroxide, inhibition of eNOS and increased levels of mitochondrial ROS, including compromised mitochondrial dynamics, loss of calcium ion homeostasis and inactivation of SIRT-1-mediated signalling pathways. Next, loss of cellular redox homeostasis is considered, including further aspects of the roles of hydrogen peroxide signalling, the pathological consequences of elevated NF-κB, compromised S-nitrosylation and the development of hypernitrosylation and increased transcription of atherogenic miRNAs. These molecular aspects are then applied to neuroprogressive disorders by considering the following potential generators of endothelial dysfunction and activation in major depressive disorder, bipolar disorder and schizophrenia: NF-κB; platelet activation; atherogenic miRs; myeloperoxidase; xanthene oxidase and uric acid; and inflammation, oxidative stress, nitrosative stress and mitochondrial dysfunction.

CONCLUSIONS

Finally, on the basis of the above molecular mechanisms, details are given of potential treatment options for mitigating endothelial cell dysfunction and activation in neuroprogressive disorders.

Effect of short-acting exenatide administered three times daily on markers of cardiovascular disease in type 1 diabetes: A randomized double-blind placebo-controlled trial

AIMS

To investigate the effect of adding the short-acting glucagon-like peptide 1 receptor agonist (GLP-1RA) exenatide to insulin treatment on markers of cardiovascular risk in type 1 diabetes.

MATERIALS AND METHODS

In a randomized, double-blind, parallel-group trial, 108 individuals with type 1 diabetes aged ≥18 years on multiple daily injection therapy with a body mass index >22.0 kg/m² and glycated haemoglobin concentration of 59 to 88 mmol/mol (7.5%-10.0%) were randomized (1:1) to preprandial subcutaneous injection of 10 μg exenatide (Byetta®) or placebo three times daily over 26 weeks as add-on treatment to existing insulin therapy. Reported markers of cardiovascular risk were secondary endpoints and were analyzed in a baseline-adjusted linear mixed model in the intention-to-treat population. The primary results of this study, the MAG1C (Meal-time Administration of exenatide for Glycaemic control in type 1 diabetes Cases) trial, were previously reported.

RESULTS

Exenatide changed total fat mass by -2.6 kg (95% confidence interval [CI] -3.6; -1.6; P < 0.0001) and lean body mass by -1.1 kg (95% CI -1.9; -0.4; P = 0.01) compared with placebo, as assessed by dual-energy X-ray absorptiometry. Fat mass reductions were similar for central and peripheral fat mass. Exenatide did not change levels of interleukin-2 or -6; tumour necrosis factor-α; C-reactive protein; N-terminal prohormone of brain natriuretic peptide; or 8-oxo-7,8-dihydroguanosine (RNA oxidation marker) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (DNA oxidation marker).

CONCLUSIONS

Exenatide added to insulin therapy in type 1 diabetes for 26 weeks resulted in body weight loss primarily from fat mass reduction, but had no effect on biomarkers of cardiovascular disease risk.

Urinary markers of nucleic acid oxidation increase with age, obesity and insulin resistance in Danish children and adolescents

PURPOSE

Oxidative stress may play an important role in childhood obesity and increased cardiometabolic risk. 8-oxo-7,8-dihydroguanosine (8-oxoGuo) from oxidation of RNA and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) from oxidation of DNA are excreted into urine and function as biomarkers for oxidative stress reflecting the modification rate of nucleic acids by oxidation. This study investigates the associations between urinary markers of nucleic acid oxidation and Body Mass Index (BMI), age, sex and cardiometabolic risk factors in children and adolescents with and without obesity.

METHODS

We studied 543 children and adolescents from an obesity clinic cohort (n = 418) and a population-based cohort (n = 125), all aged 6-18 years. Anthropometrics, urine and blood samples were collected. A validated liquid chromatography-tandem mass spectrometry method was used to measure the nucleic acid oxidation markers.

RESULTS

Compared with the population-based cohort, children and adolescents in the obesity clinic cohort had higher calculated 24-h excretion of 8-oxoGuo (p = 0.045) and 8-oxodG (p = 0.014) adjusted for basal metabolic rate. Both oxidation markers were positively associated with age and female sex (all p < 0.002). In the obesity clinic cohort the RNA oxidation marker 8-oxoGuo correlated with serum insulin (rho = 0.18, p = <.001) and insulin resistance (rho = 0.19, p = <.001).

CONCLUSIONS

Childhood obesity associate with higher urinary excretion of nucleic acid oxidation biomarkers, and increase with age throughout childhood, mirroring the obesity- and age-related increase shown in adults. Finally, children with obesity and insulin resistance had higher RNA oxidation markers than children with obesity and no insulin resistance, supporting a possible link between oxidative stress and the pathogenesis of cardiometabolic risk including type 2 diabetes.

Increased oxidative stress with substantial dysregulation of genes related to oxidative stress and DNA repair after laparoscopic colon cancer surgery

Surgical stress is followed by oxidative stress, where reactive oxygene species may act as regulators of pathways related to cancer cell survival and metastatic ability. Furthermore, reactive oxygene species may cause DNA and RNA damage. The aim of this study was to examine whether laparoscopic colon cancer surgery causes oxidative stress and dysregulation of related pathways.

METHODS

Patients undergoing elective laparoscopic surgery for colon cancer were included. Blood and urine samples were drawn on the day prior to surgery and on day 1 and 10 after surgery.

RESULTS

Twenty-six patients were included. Out of 140 genes previously identified as sensitive to regulation by reactive oxygene species, 46 were significantly differentially expressed on day 1 after surgery (FDR < 0.05). Upregulated genes were related to cellular immune suppression, proliferation, migration and epithelial to mesenchymal transition. Downregulated genes were related to IFN pathways and cytotoxic immunological reactions. Genes related to DNA repair were primarily downregulated on day one after surgery, and urinary excretion of 8oxdG was decreased on day two after (p = 0.004), and increased on day 10 after surgery (p = 0.01).

CONCLUSION

Laparoscopic colon cancer surgery causes oxidative stress, and impaired DNA repair. Gene expression profiling indicates that reactive oxygen species may act as regulators of pathways related to increased risk of metastasis and cellular immune suppression after surgery. Measures of intracellular oxidative stress, indicates impaired DNA repair on day two after surgery, and sustained oxidative stress on day 10 after surgery.

Are remitted affective disorders and familial risk of affective disorders associated with metabolic syndrome, inflammation and oxidative stress? - a monozygotic twin study

BACKGROUND

Metabolic syndrome (MetS) is associated with reduced life expectancy in patients with affective disorders, however, whether MetS also plays a role before the onset of affective disorder is unknown. We aimed to investigate whether MetS, inflammatory markers or oxidative stress act as risk factors for affective disorders, and whether MetS is associated with increased inflammation and oxidative stress.

METHODS

We conducted a high-risk study including 204 monozygotic (MZ) twins with unipolar or bipolar disorder in remission or partial remission (affected), their unaffected co-twins (high-risk) and twins with no personal or family history of affective disorder (low-risk). Metabolic Syndrome was ascertained according to the International Diabetes Federation (IDF) criteria. Inflammatory markers and markers of oxidative stress were analyzed from fasting blood and urine samples, respectively.

RESULTS

The affected and the high-risk group had a significantly higher prevalence of MetS compared to the low-risk group (20% v. 15% v. 2.5%, p = 0.0006), even after adjusting for sex, age, smoking and alcohol consumption. No differences in inflammatory and oxidative markers were seen between the three groups. Further, MetS was associated with alterations in inflammatory markers, and oxidative stress was modestly correlated with inflammation.

CONCLUSION

Metabolic syndrome is associated with low-grade inflammation and may act as a risk factor and a trait marker for affective disorders. If confirmed in longitudinal studies, this suggests the importance of early intervention and preventive approaches targeted towards unhealthy lifestyle factors that may contribute to later psychopathology.

Differential time responses in inflammatory and oxidative stress markers after a marathon: An observational study

Acute and adaptive changes in systemic markers of oxidatively generated nucleic acid modifications (i.e., 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo)) as well as inflammatory cytokines (i.e., C-reactive protein, interleukin-6, interleukin-10, and tumour necrosis factor alpha), a liver hormone (i.e., fibroblast growth factor 21 (FGF21)), and bone metabolism markers (sclerostin, osteocalcin, C-terminal telopeptide, and N-terminal propeptide of type 1 procollagen) were investigated following a marathon in 20 study participants. Immediate changes were observed in inflammatory cytokines, FGF21, and bone metabolism markers following the marathon. In contrast, no immediate changes in urinary excretion of 8-oxodG and 8-oxoGuo were evident. Four days after the marathon, decreased urinary excretion of 8-oxodG (-2.9 (95% CI -4.8;-1.1) nmol/24 h, P < 0.01) and 8-oxoGuo (-5.8 (95% CI -10.3;-1.3) nmol/24 h, P = 0.02) was observed. The excretion rate of 8-oxodG remained decreased 7 days after the marathon compared to baseline (-2.3 (95%CI -4.3;-0.4) nmol/24 h, P = 0.02), whereas the excretion rate of 8-oxoGuo was normalized. In conclusion marathon participation immediately induced a considerable inflammatory response, but did not increase excretion rates of oxidatively generated nucleic acid modifications. In fact, a delayed decrease in oxidatively generated nucleic acid modifications was observed suggesting adaptive antioxidative effects following exercise.

ABBREVIATIONS

8-oxodG: 8-oxo-7,8-dihydro-2'-deoxyguanosine; 8-oxoGuo: 8-oxo-7,8-dihydroguanosine; CI: confidence interval; CTX: C-terminal telopeptide of type 1 collagen; DXA: dual-energy X-ray absorptiometry; ELISA: enzyme-linked immunosorbent assay; FGF21: Fibroblast growth factor 21; h: hour; hsCRP: high sensitivity C-reactive protein; IL: interleukin; IQR: interquartile range; MS: mass spectrometry: P1NP: N-terminal propeptide of type 1 procollagen; TNFα: tumour necrosis factor alpha; UPLC: ultra-performance liquid chromatography.

Current perspectives on the clinical implications of oxidative RNA damage in aging research: challenges and opportunities

Ribonucleic acid (RNA) molecules can be easily attacked by reactive oxygen species (ROS), which are produced during normal cellular metabolism and under various oxidative stress conditions. Numerous findings report that the amount of cellular 8-oxoG, the most abundant RNA damage biomarker, is a promising target for the sensitive measurement of oxidative stress and aging-associated diseases, including neuropsychiatric disorders. Most importantly, available data suggest that RNA oxidation has important implications for various signaling pathways and gene expression regulation in aging-related diseases, highlighting the necessity of using combinations of RNA oxidation adducts in both experimental studies and clinical trials. In this review, we primarily describe evidence for the effect of oxidative stress on RNA integrity modulation and possible quality control systems. Additionally, we discuss the profiles and clinical implications of RNA oxidation products that have been under intensive investigation in several aging-associated medical disorders.

Effects of a highly controlled carbohydrate-reduced high-protein diet on markers of oxidatively generated nucleic acid modifications and inflammation in weight stable participants with type 2 diabetes; a randomized controlled trial

Carbohydrate-restricted diets are increasingly recognized as options for dietary management of type 2 diabetes mellitus (T2DM). We investigated the effects of a carbohydrate-reduced high-protein (CRHP) and a conventional diabetes (CD) diet on oxidative stress and inflammation in weight stable individuals with T2DM. We hypothesized that the CRHP diet would improve markers of oxidatively generated RNA and DNA modifications as well as inflammatory parameters. Thirty participants with T2DM were randomized to 6 weeks of CRHP or CD dietary treatment (30/50 energy percentage (E%) carbohydrate, 30/17E% protein, 40/33E% fat), followed by a cross-over to the opposite diet for a subsequent 6-week period. All meals were provided during the study and body weight was controlled. Diurnal urine samples were collected after 4 weeks on each diet and oxidatively generated RNA and DNA modifications were measured as 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), respectively. Fasting concentrations of soluble urokinase plasminogen activator receptor, high-sensitivity C-reactive protein, tumor necrosis factor alpha and interleukin-6 were measured before and after 6 weeks of interventions. Compared with the CD diet, the CRHP diet increased 24-hour urinary excretion of 8-oxoGuo by 9.3% (38.6 ± 12.6 vs. 35.3 ± 11.0 nmol/24 h, p = .03), whereas 8-oxodG did not differ between diets (24.0 ± 9.5 vs. 24.8 ± 11.1 nmol/24 h, p = .17). Changes in plasma inflammatory parameters did not differ between CRHP and CD diets, all p ≥ .2. The clinical implications of increased RNA oxidation following a CRHP diet as well as long-term effects of carbohydrate-restriction on markers of oxidatively generated nucleic acid modifications should be a field of future study.

Changes in oxidative nucleic acid modifications and inflammation following one-week treatment with the bile acid sequestrant sevelamer: Two randomised, placebo-controlled trials

AIMS

Sevelamer has been reported to have anti-oxidative and anti-inflammatory effects as well as effects on glycaemic control and plasma lipids. The aim of this study was to determine the effects of one-week treatment with sevelamer on oxidative nucleic acid modifications and inflammation markers.

METHODS

Two double-blinded studies including 30 patients with type 2 diabetes (T2D) and 20 healthy individuals were conducted. Participants were randomised to one week of treatment with sevelamer (1600 mg three times daily) or placebo. RNA and DNA oxidation, measured by urinary excretion of 8-oxo-7,8-dihydroguanosine(8-oxoGuo) and (8-oxo-7,8-dihydro-2'-deoxyguanosine(8-oxodG), and markers of inflammation were determined before and after the intervention.

RESULTS

In patients with T2D there was no significant placebo-corrected reduction in 8-oxoGuo or 8-oxodG. However, a reduction in 8-oxoGuo was observed within the group treated with sevelamer (∆8-oxoGuo/creatinine (median[IQR]): -0.04 [-0.24; 0.01] nmol/mmol, p = 0.02). A sevelamer-mediated reduction in interleukin-2 (p = 0.04) and a trend towards reduction in interleukin-6 (p = 0.053) were found in patients with T2D.

CONCLUSIONS

This study reveals a potential effect of sevelamer treatment on inflammation and possible oxidative RNA modifications. The potential protective effects of sevelamer in terms of cardiovascular disease in patients with T2D need further investigation.

Factors associated with high oxidative stress in patients with type 2 diabetes: a meta-analysis of two cohort studies

OBJECTIVE

Our objective is to identify the potential factors associated with serum Diacron's reactive oxygen metabolites test (D-ROM) levels of patients with type 2 diabetes mellitus (T2DM) by conducting cross-sectional and longitudinal analyses in two large cohorts and further strengthening these results by performing a meta-analysis.

METHODS

Serum D-ROM concentrations were measured in 1045 and 1101 patients with T2DM from two independent cohort studies from Germany at baseline and repeatedly 3-4 years later. The cross-sectional and longitudinal associations of various potential determinants with D-ROM levels were assessed with a backwards selection algorithm in multivariable adjusted models.

RESULTS

In the meta-analysis of the cross-sectional analysis, female sex, low education, obesity, smoking, high total cholesterol, hemoglobin A_1c ≥7%, no diabetes medication, a history of myocardial infarction, heart failure, a history of cancer and C reactive protein levels (CRP) >3 mg/L were statistically significantly associated with increased D-ROM levels in patients with T2DM. The meta-analysis of the longitudinal analysis revealed that old age, female sex, obesity, smoking, physical inactivity, high alcohol consumption, ≥5 years since diabetes diagnosis and CRP levels between 3 mg/L and 10 mg/L were statistically significantly associated with D-ROM levels measured 3-4 years later.

CONCLUSIONS VALIDITY, LIMITATIONS AND CLINICAL APPLICABILITY

This comprehensive analysis confirmed that several modifiable risk factors are being associated with oxidative stress in patients with T2DM within an observational study design. We discuss potential prevention measures against these risk factors that might help to reduce oxidative stress and to prevent some cases of premature mortality in patients with T2DM.

Atorvastatin for prevention of disease progression and hospitalisation in liver cirrhosis: protocol for a randomised, double-blind, placebo-controlled trial

INTRODUCTION

Patients with liver cirrhosis are often diagnosed late and once complications are present, the 2-year survival is 50%. Increasing evidence supports systemic inflammation and metabolic dysfunction in the hepatic stellate cell as key drivers of progression of cirrhosis. However, there is no registered medication, that targets inflammation and cellular dysfunction in the liver.

METHODS AND ANALYSIS

In a randomised double-blind and placebo-controlled trial with atorvastatin for liver cirrhosis, we aim to investigate clinical endpoints of survival, hospitalisations and safety, but also exploratory endpoints of genomics and protein functions in the liver.

ETHICS AND DISSEMINATION

There is no registered medication that actively prevents development of complications or systemic inflammation in liver cirrhosis. All patients continue regular clinical management during the trial period. Atorvastatin has been on the market for several years with a safety profile that is acceptable even in patients with liver disease. A beneficial effect of atorvastatin on clinical outcomes in cirrhosis will provide cheap and effective causal treatment for chronic liver disease. The trial is registered by the Danish Data Protection Agency (P-2019-635) and approved by the Danish Medicines Agency (EudraCT 2019-001806-40) and the Scientific Ethics Committee of the Capital Region of Denmark (H-19030643) before initiation. Reporting of the trial will follow the Consolidated Standards of Reporting Trials guidelines for reporting of randomised clinical trials.

TRIAL REGISTRATION NUMBER

The trial is registered in clinicaltrials.gov (NCT04072601) and in clinicaltrialsregister.eu (EudraCT 2019-001806-40) (Pre-results).

Oxidatively Damaged DNA/RNA and 8-Isoprostane Levels Are Associated With the Development of Type 2 Diabetes at Older Age: Results From a Large Cohort Study

OBJECTIVE

Oxidative stress is believed to play an important role in the pathophysiology of type 2 diabetes, but the few cohort studies that have assessed the association of oxidative stress biomarkers with type 2 diabetes incidence were small and reported inconclusive results.

RESEARCH DESIGN AND METHODS

We examined the associations of urinary oxidized guanine/guanosine (OxGua) levels (a biomarker of DNA/RNA oxidation) and urinary 8-isoprostane levels (a biomarker of lipid peroxidation) with type 2 diabetes incidence in 7,828 individuals initially without diabetes from a population-based German cohort study with 14 years of follow-up. Hazard ratios (HRs) (95% CIs) per 1 SD were obtained using multivariable-adjusted Cox proportional hazards regression models.

RESULTS

In the total population, weak but statistically significant associations with type 2 diabetes incidence were observed for OxGua levels (HR [95% CI] per 1 SD 1.05 [1.01; 1.09]) and 8-isoprostane levels (1.04 [1.00; 1.09]). Stratified analyses showed that associations of both biomarkers with type 2 diabetes incidence were absent in the youngest age-group (50-59 years) and strongest in the oldest age-group (65-75 years) of the cohort, with HR of OxGua levels 1.14 (1.05; 1.23) per 1 SD and of 8-isoprostane levels 1.22 (1.02; 1.45) per 1 SD.

CONCLUSIONS

These results from a large cohort study support suggestions that an imbalanced redox system contributes to the development of type 2 diabetes but suggest that this association becomes clinically apparent at older ages only, possibly as a result of reduced cellular repair capacity.

Predicting Treatment Outcome in Major Depressive Disorder Using Serotonin 4 Receptor PET Brain Imaging, Functional MRI, Cognitive-, EEG-Based, and Peripheral Biomarkers: A NeuroPharm Open Label Clinical Trial Protocol

BACKGROUND

Between 30 and 50% of patients with major depressive disorder (MDD) do not respond sufficiently to antidepressant regimens. The conventional pharmacological treatments predominantly target serotonergic brain signaling but better tools to predict treatment response and identify relevant subgroups of MDD are needed to support individualized and mechanistically targeted treatment strategies. The aim of this study is to investigate antidepressant-free patients with MDD using neuroimaging, electrophysiological, molecular, cognitive, and clinical examinations and evaluate their ability to predict clinical response to SSRI treatment as individual or combined predictors.

METHODS

We will include 100 untreated patients with moderate to severe depression (>17 on the Hamilton Depression Rating Scale 17) in a non-randomized open clinical trial. We will collect data from serotonin 4 receptor positron emission tomography (PET) brain scans, functional magnetic resonance imaging (fMRI), electroencephalogram (EEG), cognitive tests, psychometry, and peripheral biomarkers, before (at baseline), during, and after 12 weeks of standard antidepressant treatment. Patients will be treated with escitalopram, and in case of non-response at week 4 or intolerable side effects, offered to switch to a second line treatment with duloxetine. Our primary outcome (treatment response) is assessed using the Hamilton depression rating subscale 6-item scores at week 8, compared to baseline. In a subset of the patients (n = ~40), we will re-assess the neurobiological response (using PET, fMRI, and EEG) 8 weeks after initiated pharmacological antidepressant treatment, to map neurobiological signatures of treatment responses. Data from matched controls will either be collected or is already available from other cohorts.

DISCUSSION

The extensive investigational program with follow-up in this large cohort of participants provides a unique possibility to (a) uncover potential biomarkers for antidepressant treatment response, (b) apply the findings for future stratification of MDD, (c) advance the understanding of pathophysiological underpinnings of MDD, and (d) uncover how putative biomarkers change in response to 8 weeks of pharmacological antidepressant treatment. Our data can pave the way for a precision medicine approach for optimized treatment of MDD and also provides a resource for future research and data sharing.

CLINICAL TRIAL REGISTRATION

The study was registered at clinicaltrials.gov prior to initiation (NCT02869035; 08.16.2016, URL: https://clinicaltrials.gov/ct2/results?cond=&term=NCT02869035&cntry=&state=&city=&dist=).

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.

Markers of HPA-axis activity and nucleic acid damage from oxidation after electroconvulsive stimulations in rats

OBJECTIVE

Oxidative stress has been suggested to increase after electroconvulsive therapy (ECT), a treatment which continues to be the most effective for severe depression. Oxidative stress could potentially be mechanistically involved in both the therapeutic effects and side effects of ECT.

METHODS

We measured sensitive markers of systemic and central nervous system (CNS) oxidative stress on DNA and RNA (urinary 8-oxodG/8-oxoGuo, cerebrospinal fluid 8-oxoGuo, and brain oxoguanine glycosylase mRNA expression) in male rats subjected to electroconvulsive stimulations (ECS), an animal model of ECT. Due to the previous observations that link hypothalamic-pituitary-adrenal (HPA)-axis activity and age to DNA/RNA damage from oxidation, groups of young and middle-aged male animals were included, and markers of HPA-axis activity were measured.

RESULTS

ECS induced weight loss, increased corticosterone (only in middle-aged animals), and decreased cerebral glucocorticoid receptor mRNA expression, while largely leaving the markers of systemic and CNS DNA/RNA damage from oxidation unaltered.

CONCLUSION

These results suggest that ECS is not associated with any lasting effects on oxidative stress on nucleic acids neither in young nor middle-aged rats.

Oxidatively generated modifications to nucleic acids in vivo: Measurement in urine and plasma

BACKGROUND

The oxidized guanine nucleosides, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo), derived from DNA and RNA, respectively, were used to investigate the importance of oxidative stress to nucleic acids in vivo. High urinary excretion of 8-oxodG is associated with cancer development, whereas high urinary excretion of 8-oxoGuo is associated with mortality in type 2 diabetes. Like creatinine, these small water-soluble molecules are not reabsorbed in the kidney. Therefore, 8-oxo nucleoside/creatinine reciprocal concentration ratios are identical in plasma and urine. The total amount of 8-oxo guanine nucleosides excreted by the kidneys is the product of plasma concentration and glomerular filtration rate.

METHODS

With relevant equations and an estimated glomerular filtration rate, the 24-h urinary excretion of 8-oxodG and 8-oxoGuo was calculated in 2679 subjects with type 2 diabetes, displaying good correlation with the measured urinary 8-oxo nucleoside/creatinine ratio: DNA oxidation r = 0.86 and RNA oxidation r = 0.84 (p < 0.05 for both).

RESULTS

Survival analyses based on the quartiles of the 8-oxodG/creatinine ratio and the quartiles of calculated 24-h urinary excretion rate of the 2679 subjects gave similar hazard ratio estimates for death due to all causes. This finding was similar for the 8-oxoGuo hazard ratio estimates.

CONCLUSIONS

This study shows that oxidatively generated modifications to DNA and RNA in vivo can be measured using 1) a spot urine sample, normalized to urinary creatinine, 2) 24-h urine, or 3) a single plasma sample based on concentrations of 8-oxo nucleoside and creatinine and glomerular filtration rate.

Cerebrospinal fluid oxidative stress metabolites in patients with bipolar disorder and healthy controls: a longitudinal case-control study

Bipolar disorder (BD) is a mental disorder characterized by recurrent relapses of affective episodes, cognitive impairment, illness progression, and reduced life expectancy. Increased systemic oxidatively generated nucleoside damage have been found in some neurodegenerative disorders and in BD. As the first, this naturalistic prospective, longitudinal follow-up case-control study investigated cerebrospinal fluid (CSF) oxidative stress markers 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) that relate to RNA and DNA damage, respectively. Patients with BD (n = 86, 51% female) and gender-and-age-matched healthy control individuals (HC; n = 44, 44% female) were evaluated at baseline (T0), during (T1) and after a new affective episode (T2), if it occurred, and after a year (T3). Cerebrospinal and urine oxidative stress markers were analyzed using ultra-performance liquid chromatography-tandem mass spectrometry. CSF-8-oxoGuo was statistically significantly higher by 18% (p = 0.003) in BD versus HC at T0, and by 22% (p = 0) at T3. CSF-8-oxoGuo had increased by 15% (p = 0.042) from T0 to T3, and by 14% (p = 0.021) from T2 to T3 in patients, who experienced an episode during follow-up. CSF-8-oxodG had increased by 26% (p = 0.054) from T0 to T2 and decreased by 19% (p = 0.041) from T2 to T3 in patients, who experienced an episode during follow-up. CSF-8-oxoGuo did not show a statistically significant change in HC during the one-year follow-up. CSF and urine-8-oxoGuo levels correlated moderately. In conclusion, CSF oxidative stress marker of RNA damage 8-oxoGuo showed both state and trait dependence in BD and stability in HC. Central RNA damage may be a potential biomarker for BD.

The renal hemodynamic effects of the SGLT2 inhibitor dapagliflozin are caused by post-glomerular vasodilatation rather than pre-glomerular vasoconstriction in metformin-treated patients with type 2 diabetes in the randomized, double-blind RED trial

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) improve hard renal outcomes in type 2 diabetes. This is possibly explained by the fact that SGLT2i normalize the measured glomerular filtration rate (mGFR) by increasing renal vascular resistance, as was shown in young people with type 1 diabetes and glomerular hyperfiltration. Therefore, we compared the renal hemodynamic effects of dapagliflozin with gliclazide in type 2 diabetes. The mGFR and effective renal plasma flow were assessed using inulin and para-aminohippurate clearances in the fasted state, during clamped euglycemia (5 mmol/L) and during clamped hyperglycemia (15 mmol/L). Filtration fraction and renal vascular resistance were calculated. Additionally, factors known to modulate renal hemodynamics were measured. In 44 people with type 2 diabetes on metformin monotherapy (Hemoglobin A1c 7.4%, mGFR 113 mL/min), dapagliflozin versus gliclazide reduced mGFR by 5, 10, and 12 mL/min in the consecutive phases while both agents similarly improved Hemoglobin A1c (-0.48% vs -0.65%). Dapagliflozin also reduced filtration fraction without increasing renal vascular resistance, and increased urinary adenosine and prostaglandin concentrations. Gliclazide did not consistently alter renal hemodynamic parameters. Thus, beyond glucose control, SGLT2i reduce mGFR and filtration fraction in type 2 diabetes. The fact that renal vascular resistance was not increased by dapagliflozin suggests that this is due to post-glomerular vasodilation rather than pre-glomerular vasoconstriction.

Association of Serum Markers of Oxidative Stress With Incident Major Cardiovascular Events, Cancer Incidence, and All-Cause Mortality in Type 2 Diabetes Patients: Pooled Results From Two Cohort Studies

OBJECTIVE

Oxidative stress plays an important role in the pathophysiology of type 2 diabetes mellitus (T2DM). However, associations of biomarkers of oxidative stress with diabetes complications have not yet been addressed in large cohort studies.

RESEARCH DESIGN AND METHODS

Derivatives of reactive oxygen metabolites (d-ROMs) levels, a proxy for the reactive oxygen species burden, and total thiol levels (TTLs), a proxy for the reductive capacity, were measured in 2,125 patients with T2DM from two German cohort studies of almost equal size at baseline and 3-4 years later. Multivariable adjusted Cox proportional hazards models with time-dependent modeled d-ROMs levels and TTLs were used to assess the associations with incident major cardiovascular events (MCE), cancer incidence, and all-cause mortality.

RESULTS

In total, 205, 179, and 394 MCE, cancer, and all-cause mortality cases were observed during 6-7 years of follow-up, respectively. Both oxidative stress biomarkers and the d-ROMs-to-TTL ratio were statistically significantly associated with all-cause mortality in both cohorts, and the pooled hazard ratios (HRs) and 95% CIs for top versus bottom tertiles were 2.10 (95% CI 1.43, 3.09) for d-ROMs levels, 0.59 (0.40, 0.87) for TTLs, and 2.50 (1.86, 3.36) for d-ROMs-to-TTL ratio. The d-ROMs-to-TTL ratio was also statistically significantly associated with incident MCE for top versus bottom tertile (1.65 [1.07, 2.54]), but this association did not persist after additional adjustment for chronic diseases. No associations with cancer were detected.

CONCLUSIONS

The observed strong associations of both biomarkers with mortality suggest an important contribution of an imbalanced redox system to the premature mortality of patients with diabetes.

Effect of statin treatment on circulating malondialdehyde concentrations: a systematic review and meta-analysis

Background

The effect of statins on oxidative stress markers, such as malondialdehyde (MDA), is still a matter of debate. We sought to address this issue by conducting a systematic review and meta-analysis of published data on the effect of statin treatment on systemic MDA concentrations.

Methods

A literature search was conducted on MEDLINE/PubMed, ISI Web of Sciences and Scopus. Data were pooled using a random-effects model.

Results

A total of 35 studies assessing MDA concentrations before and after statin treatment in 1512 participants (mean age 53.6 years, 48.7% males) were identified. Extreme between-study heterogeneity was observed (I² = 96.0%, p < 0.001). Pooled standardized mean difference (SMD) showed a significant reduction in plasma MDA concentrations after treatment (SMD = -1.47 µmol/l, 95% confidence interval = -1.89 to -1.05 μmol/l; p < 0.001). Similarly, a subgroup analysis of 10 studies that also included a placebo group showed a significant reduction in plasma MDA concentrations with statins (-1.03 μmol/l, 95% confidence interval = -1.52 to -0.29 μmol/l; p = 0.036).

Conclusions

This systematic review and meta-analysis showed that statin treatment significantly reduces systemic MDA concentrations. However, the results should be interpreted with caution because of extreme between-study heterogeneity, which warrants further intervention studies.

Urinary nucleic acid oxidation product levels show differential associations with pharmacological treatment in patients with type 2 diabetes

The relationship between RNA and DNA oxidation and pharmacological treatment has not been systematically investigated in patients with type 2 diabetes (T2D). We aimed to investigate the association between pharmacological treatments and levels of urinary markers of nucleic acid oxidation in T2D patients. Vejle Diabetes Biobank cohort data was nested into nationwide registry data. Multiple logistic regression was used to associate drug usage with risk of high (above median) RNA and DNA oxidation. Data from 2664 T2D patients (64% male, age range: 25-75) were included. Questionnaire-validated lipid lowering drug use was associated with low RNA oxidation (Odds ratio, OR 0.71, 95% CI: [0.59-0.87]). Insulin and non-specific antidiabetic drugs were associated with low DNA oxidation (insulin: OR 0.60, 95% CI [0.49-0.73]). Oral antidiabetics were associated with high DNA oxidation and RNA oxidation (OR 1.30, 95% CI [1.10-1.53] and OR 1.26, 95% CI [1.07-1.29]). Our findings indicate that diabetes-related drugs are associated with RNA and DNA oxidation and further studies are required to determine causality in T2D patients.

Ruxolitinib treatment reduces monocytic superoxide radical formation without affecting hydrogen peroxide formation or systemic oxidative nucleoside damage in myelofibrosis

The role of excess reactive oxygen species (ROS) with consequent DNA/RNA damage is now recognized as a hallmark of cancer. In JAK2V617F mutated myeloproliferative neoplasms, ROS have been suggested to be important factors in disease initiation and progression. Ruxolitinib is the most widely used drug for myelofibrosis, because it improves symptom-score. However, both the anti-clonal potential and improvement in overall survival are limited. We investigated the impact of ruxolitinib on formation of superoxide radical and hydrogen peroxide by monocytes in sequentially acquired blood samples from patients with myelofibrosis. We also investigated the impact on RNA and DNA damage by measuring urinary excretion of 8-oxo-Guo and 8-oxo-d-Guo. The formation of superoxide by monocytes was reduced significantly during ruxolitinib therapy, but no impact on the formation of hydrogen peroxide by monocytes or the systemic amount of oxidatively damaged RNA or DNA could be demonstrated. We conclude that ruxolitinib holds little anti-oxidative potential.