Henrik E. Poulsen

Risk of Myocardial Infarction and Death Associated With the Use of Nonsteroidal Anti‐Inflammatory Drugs (NSAIDs) Among Healthy Individuals: A Nationwide Cohort Study

Use of some nonsteroidal anti‐inflammatory drugs (NSAIDs) is associated with increased cardiovascular risk in several patient groups, but whether this excess risk exists in apparently healthy individuals has not been clarified. Using a historical cohort design, we estimated the risk of death and myocardial infarction associated with the use of NSAIDs. Participants in the study were selected from the Danish population and were defined as healthy according to a history of no hospital admissions and no concomitant selected pharmacotherapy. The source population consisted of 4,614,807 individuals, of whom 1,028,437 were included in the study after applying selection criteria. Compared to no NSAID use, hazard ratios (95% confidence limits) for death/myocardial infarction were 1.01 (0.96–1.07) for ibuprofen, 1.63 (1.52–1.76) for diclofenac, 0.97 (0.83–1.12) for naproxen, 2.13 (1.89–2.41) for rofecoxib, and 2.01 (1.78–2.27) for celecoxib. A dose‐dependent increase in cardiovascular risk was seen for selective COX‐2 inhibitors and diclofenac. Caution should be exercised in NSAID use in all individuals, and particularly high doses should be avoided if possible.

Detection and interpretation of 8-oxodG and 8-oxoGua in urine, plasma and cerebrospinal fluid☆ , ☆☆ ,★

BACKGROUNDnDNA and RNA oxidations have been linked to diseases such as cancer, arteriosclerosis, neurodegeneration and diabetes. The prototype base modification studied is the 8-hydroxylation of guanine. DNA integrity is maintained by elaborate repair systems and RNA integrity is less studied but relies mainly on degradation.nnnSCOPE OF REVIEWnDNA and RNA oxidations are measured by very similar techniques. The scope of this review is to highlight the preferred methods of measurement of oxidized nucleic acid metabolites, to highlight novel findings particularly in RNA oxidation, and to present the interpretation of the measurements.nnnMAJOR CONCLUSIONSnTissue levels are snap-shots of the level in a specific organ or cell system and reflect the balance between formation rate and elimination rate (repair), and must be interpreted as such. Urinary excretion is a global measure of oxidative stress in an organism and is therefore best suited for situations or diseases where large parts or the entire organism is stressed by oxidation. It represents the body average rate by which either RNA or DNA is oxidized and is interpreted as oxidative stress. Oxidations of RNA and DNA precursors have been demonstrated and the quantitative importance is debated.nnnGENERAL SIGNIFICANCEnCareful experimental designs and appropriate choice of methodology are paramount for correct testing of hypotheses related to oxidative stress, and pitfalls are plentiful. There is accumulating evidence that DNA oxidation is associated with disease, particularly cancer, and recent evidence points at an association between RNA oxidation and neurodegenerative diseases and diabetes. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn.

Inter-laboratory validation of procedures for measuring 8-oxo-7,8-dihydroguanine/8-oxo-7,8-dihydro-2 '-deoxyguanosine in DNA

The aim of ESCODD, a European Commission funded Concerted Action, is to improve the precision and accuracy of methods for measuring 8-oxo-7,8-dihydroguanine (8-oxoGua) or the nucleoside (8-oxodG). On two occasions, participating laboratories received samples of different concentrations of 8-oxodG for analysis. About half the results returned (for 8-oxodG) were within 20% of the median values. Coefficients of variation (for three identical samples) were commonly around 10%. A sample of calf thymus DNA was sent, dry, to all laboratories. Analysis of 8-oxoGua/8-oxodG in this sample was a test of hydrolysis methods. Almost half the reported results were within 20% of the median value, and half obtained a CV of less than 10%. In order to test sensitivity, as well as precision, DNA was treated with photosensitiser and light to introduce increasing amounts of 8-oxoGua and samples were sent to members. Median values calculated from all returned results were 45.6 (untreated), 53.9, 60.4 and 65.6 8-oxoGua/10 6 Gua; only seven laboratories detected the increase over the whole range, while all but one detected a dose response over two concentration intervals. Results in this trial reflect a continuing improvement in precision and accuracy. The next challenge will be the analysis of 8-oxodG in DNA isolated from cells or tissue, where the concentration is much lower than in calf thymus DNA.

Antidepressant Use and Risk of Out-of-Hospital Cardiac Arrest: A Nationwide Case–Time–Control Study

Treatment with some types of antidepressants has been associated with sudden cardiac death. It is unknown whether the increased risk is due to a class effect or related to specific antidepressants within drug classes. All patients in Denmark with an out‐of‐hospital cardiac arrest (OHCA) were identified (2001–2007). Association between treatment with specific antidepressants and OHCA was examined by conditional logistic regression in case–time–control models. We identified 19,110 patients with an OHCA; 2,913 (15.2%) were receiving antidepressant treatment at the time of OHCA, with citalopram being the most frequently used type of antidepressant (50.8%). Tricyclic antidepressants (TCAs; odds ratio (OR) = 1.69, confidence interval (CI): 1.14–2.50) and selective serotonin reuptake inhibitors (SSRIs; OR = 1.21, CI: 1.00–1.47) were both associated with comparable increases in risk of OHCA, whereas no association was found for serotonin–norepinephrine reuptake inhibitors/noradrenergic and specific serotonergic antidepressants (SNRIs/NaSSAs; OR = 1.06, CI: 0.81–1.39). The increased risks were primarily driven by: citalopram (OR = 1.29, CI: 1.02–1.63) and nortriptyline (OR = 5.14, CI: 2.17–12.2). An association between cardiac arrest and antidepressant use could be documented in both the SSRI and TCA classes of drugs.

High fat diet induced oxidative DNA damage estimated by 8-oxo-7,8-dihydro-2′-deoxyguanosine excretion in rats

The role of dietary fats and energy in carcinogenesis has been partly related to oxidative damage to DNA. We have investigated the effect of dietary fat content and saturation on the urinary excretion of 8-oxo-7,8dihydro-2-deoxyguanosine (8-oxodG) in male and female rats. Groups of Fischer F344 rats (n = 6-10) were fed control chow (3.4% fat) or diets containing 21.8% corn oil or 19.8% coconut oil + 2% corn oil for 12-15 weeks. At the end of the diet intervention period 24h urine was collected for determination of 8-oxodG by HPLC. In the male groups fed control, corn oil and coconut oil diet the excretion of 8-oxodG was 403+/-150, 932+/-198 and 954+/-367pmol/kg 24 h, respectively (p < 0.05). In the female groups fed control and corn oil diet the excretion of 8-oxodG was 752+/-80 and 2206+/-282 pmol/kg 24 h, respectively (p < 0.05). Calculated per whole animal the excretion was 137+/-51, 324+/-70 and 328+/-128 pmol/24 h in the control, corn and coconut oil male groups and 156+/-21 and 464+/-56 pmol/24 h in the control and corn oil female groups, respectively ( p < 0.05). Thus, per animal or per consumed energy there was much less difference in 8-oxodG excretion between the corresponding male and female groups and only significant difference between the high fat groups. There was a close correlation (r = 0.7; p < 0.05) between 8-oxodG excretion and the energy intake. The present study suggests that a high fat diet increases oxidative DNA modification substantially irrespective of the saturation level of the fat. Energy intake appears to be the major determinant of the rate of modification.

The 10 basic requirements for a scientific paper reporting antioxidant, antimutagenic or anticarcinogenic potential of test substances in in vitro experiments and animal studies in vivo

There is increasing evidence that chemicals/test substances cannot only have adverse effects, but that there are many substances that can (also) have a beneficial effect on health. As this journal regularly publishes papers in this area and has every intention in continuing to do so in the near future, it has become essential that studies reported in this journal reflect an adequate level of scientific scrutiny. Therefore a set of essential characteristics of studies has been defined. These basic requirements are default properties rather than non-negotiables: deviations are possible and useful, provided they can be justified on scientific grounds. The 10 basic requirements for a scientific paper reporting antioxidant, antimutagenic or anticarcinogenic potential of test substances in in vitro experiments and animal studies in vivo concern the following areas: (1) Hypothesis-driven study design; (2) The nature of the test substance; (3) Valid and invalid test systems; (4) The selection of dose levels and gender; (5) Reversal of the effects induced by oxidants, carcinogens and mutagens; (6) Route of administration; (7) Number and validity of test variables; (8) Repeatability and reproducibility; (9) Statistics; and (10) Quality Assurance.

Vitamin C deficiency in weanling guinea pigs: differential expression of oxidative stress and DNA repair in liver and brain

Neonates are particularly susceptible to malnutrition due to their limited reserves of micronutrients and their rapid growth. In the present study, we examined the effect of vitamin C deficiency on markers of oxidative stress in plasma, liver and brain of weanling guinea pigs. Vitamin C deficiency caused rapid and significant depletion of ascorbate (P < 0.001), tocopherols (P < 0.001) and glutathione (P < 0.001), and a decrease in superoxide dismutase activity (P = 0.005) in the liver, while protein oxidation was significantly increased (P = 0.011). No changes in lipid oxidation or oxidatively damaged DNA were observed in this tissue. In the brain, the pattern was markedly different. Of the measured antioxidants, only ascorbate was significantly depleted (P < 0.001), but in contrast to the liver, ascorbate oxidation (P = 0.034), lipid oxidation (P < 0.001), DNA oxidation (P = 0.13) and DNA incision repair (P = 0.014) were all increased, while protein oxidation decreased (P = 0.003). The results show that the selective preservation of brain ascorbate and induction of DNA repair in vitamin C-deficient weanling guinea pigs is not sufficient to prevent oxidative damage. Vitamin C deficiency may therefore be particularly adverse during the neonatal period.

Association of beta‐adrenergic receptor polymorphisms and mortality in carvedilol‐treated chronic heart‐failure patients

AIMnPharmacogenetics can be used as a tool for stratified pharmacological therapy in cardiovascular medicine. We investigated whether a predefined combination of the Arg389Gly polymorphism in the adrenergic β(1) -receptor gene (ADRB1) and the Gln27Glu polymorphism in the adrenergic β(2) -receptor gene (ADRB2) could predict survival in carvedilol- and metoprolol-treated chronic heart failure (HF) patients.nnnMETHODSnFive hundred and eighty-six HF patients (carvedilol n= 82, metoprolol n= 195) were genotyped for ADRB1 Arg389Gly (rs1801253) and ADRB2 Gln27Glu (rs1042714). The end-point was all-cause mortality, and median follow-up time was 6.7 years. Patients were classified into two functional genotype groups: group 1 combination of Arg389-homozygous and Gln27-carrier (46%) and group 2 any other genotype combination (54%). Results were fitted in two multivariate Cox models.nnnRESULTSnThere was a significant interaction between functional genotype group and carvedilol treatment (adjusted(1) P= 0.033, adjusted(2) P= 0.040). Patients treated with carvedilol had shorter survival in functional genotype group 1 (P= 0.004; adjusted(1) hazard ratio (HR) 2.67, 95% CI 1.27, 5.59, P= 0.010; adjusted(2) HR 2.05, 95% CI 1.06, 3.95, P= 0.033). There was no interaction between genotype group and metoprolol treatment (P= 0.61), and there was no difference in overall survival between genotype groups (P= 0.69).nnnCONCLUSIONSnA combination of ADRB1 Arg389-homozygous and ADRB2 Gln27-carrier in HF patients treated with carvedilol was associated with a two-fold increase in mortality relative to all other genotype combinations. There was no difference in survival in metoprolol-treated HF patients between genotype groups. Patients in genotype group 1 may benefit more from metoprolol than carvedilol treatment.

Systemic oxidatively generated DNA/RNA damage in clinical depression: associations to symptom severity and response to electroconvulsive therapy.

BACKGROUNDnDepression has been associated with increased oxidative stress and hypothesized to accelerate aging. Nucleic acid damage from oxidation is a critical part of the aging process, and a suggested early event in age-related somatic morbidities that are also prevalent in depression, such as dementia and type 2 diabetes. We hypothesized that increased severity of depression is associated with increased systemic oxidatively generated DNA and RNA damage, and that this increase is attenuated by an effective antidepressant treatment.nnnMETHODSnThe urinary excretion of markers of systemic oxidatively generated DNA and RNA damage, 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoGuo), respectively, were determined in healthy controls (N=28), moderately depressed, non-medicated patients (N=26) and severely depressed patients eligible for electroconvulsive therapy (ECT) (N=29). In the severely depressed patient group, samples were also obtained 1 week after the completion of ECT.nnnRESULTSnSystemic RNA damage from oxidation, as measured by 8-oxoGuo excretion, was higher with increasing severity of depression (controls<moderately depressed<severely depressed) (P for trend=0.004). The 8-oxoGuo excretion was further increased after clinically effective ECT compared with pre-ECT values (P=0.006). There were no differences in 8-oxodG excretion between the groups or pre- vs. post-ECT.nnnLIMITATIONSnSmall sample size and the inclusion of both unipolar and bipolar patients in the severely depressed group.nnnCONCLUSIONSnSevere depression is associated with increased systemic oxidatively generated RNA damage, which may be an additional factor underlying the somatic morbidity and neurodegenerative features associated with depression. Due to the lack of normalization by clinically effective ECT, the phenomenon does not appear to be causally linked to the depressive state per se.

Genetic variation in the hTAS2R38 taste receptor and brassica vegetable intake

Abstract The human TAS2R38 receptor is believed to be partly responsible for the ability to taste phenylthiocarbamide (PTC), a bitter compound very similar to the bitter glucosinolates found in brassica vegetables. These vegetables and their active compounds have chemo-protective properties. This study investigated the relationship between genetic variation in the hTAS2R38 receptor and the actual consumption of brassica vegetables with the hypothesis that taster status was associated with intake of these vegetables. Furthermore, secondary intake information on alcohol, chocolate, coffee, smoking, BMI and waist-circumference was analysed for association with the hTAS2R38 receptor polymorphisms. The subjects were selected from the Diet, Cancer and Health (DCH) study, which is an ongoing prospective Danish cohort study. Two groups, each consisting of 250 healthy subjects were selected based on their brassica vegetables intake from the upper quartile (≥23 g/day) and the lower quartile (≤7 g/day) daily intake of brassicas from a randomly selected sub-cohort of DCH. DNA was analysed for three functional SNPs in the hTAS2R38 gene. The hTAS2R38 bitter taste receptor haplotypes were not associated with the daily intake of brassica vegetables in our study, and no association between the haplotypes and any of the other variables tested was found. We have demonstrated that the hTAS2R38 haplotypes are not associated with brassica vegetable intake and that results from experimental setups cannot be applied directly to the everyday situation. This indicates that non-genetic factors may have more influence on dietary choice than genetics.