Measurement Of Urinary Excretion Research Articles

A method for tracking a case under chelation using urinary excretion measurements

A method for tracking a case under chelation using urinary excretion measurements

Comparison of Different Methods of Urinary Protein Excretion Measurement: Is the King Really Dead?

Introduction: Assessing proteinuria is of uttermost importance for a nephrologist. It is often indispensable to accurately quantify the amount of protein lost, hence complicated and time-consuming urine collections (the gold standard or “king” of methods – 24-h protein excretion rate [PER]) are often replaced by spot urinary protein to creatinine ratio (PCR). The aim of the study was to determine whether the latter can reliably compare to the gold standard and whether “timing” of a spot urine sample is essential. Methods: We performed a prospective, single-center study of 143 consecutive adult patients with glomerular proteinuria (a total of 187 cases). Protein and creatinine concentration was measured in 3 consecutive urine samples (starting with the first morning void) and a simultaneous 24-h urine collection. Agreement between 24-h PER and PCR was evaluated with Bland-Altman plots. Results: Compared to PER 3 consecutive PCRs were 0.86, 0.66, and 0.50 higher with wide limits of agreement respectively. The bias between 2 methods was influenced by sex, CKD stage, albumin concentration and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker treatment. In 24 participants, in whom at least 2 measurements at different time points were available, only 88% of differences were lower than the calculated repeatability coefficient. Conclusions: Unfortunately although random PCR correlates with 24-h protein excretion, the scatter of differences increases as 24-h proteinuria rises (without any significant effect of the sampling time). The observed lack of agreement makes PCR an unsuitable parameter to correctly quantify proteinuria; it is also not useful for monitoring the amount of daily proteinuria in the same patient. Therefore, while searching for new markers, nephrologists can only say: “long live the king!”

Changes in Brachial and Central Blood Pressure after Short Term Continuous Positive Airway Pressure Treatment of Patients with Moderate-to-Severe Obstructive Sleep Apnoea and Impaired Renal Function

Background: Previous studies of continuous positive airway pressure (CPAP) treatment for obstructive sleep apnoea (OSA) have shown conflicting results on the effect on blood pressure (BP), and patients with chronic kidney disease (CKD) have not been included in these studies. As OSA is a frequent comorbidity in patients with CKD, it is of relevance to evaluate the effect of CPAP treatment on BP in this population. Aim: In this prospective follow-up study, we measured the effect of short term CPAP treatment of moderate-to-severe OSA on brachial and central BP, plasma level of syndecan-1 and vasoactive hormones, renal handling of sodium, subjective sleepiness, and quality of life in patients with impaired renal function. Methods: From December 2015 until March 2017, 25 patients were invited to participate in the study at the University Clinic in Nephrology and Hypertension, Aarhus University and Holstebro Hospital. At baseline and at follow-up after three to four months of CPAP treatment, we performed 24 h brachial and central ambulatory BP measurement, blood sampling measurements of plasma concentrations of syndecan-1, renin, angiotensin II, aldosterone, vasopressin, creatinine, haemoglobin A1c, and cholesterol, cardio respiratory monitoring, 24 h urine collection for measurement of urinary excretion of albumin, aquaporin-2, and epithelial sodium channel, Epworth Sleepiness Scale (ESS), and SF-36 (quality of life). Results: At follow-up, the 17 included patients with mean baseline estimated glomerular filtration rate 66 mL/min/1.73 m2 had a significant decrease in systolic office-, 24 h- and daytime-BP (13, 7, and 8 mmHg, respectively, p Conclusion: Short-term CPAP treatment of patients with moderate-to-severe OSA and reduced renal function decreased 24 h- and daytime-BP significantly and reduced urinary albumin excretion. Our results underline the importance of treatment of OSA in hypertensive patients with impaired renal function.

Assessing the impact of oral iodine supplementation on whole body iodine store, thyroid autoimmunity and serum biochemistry profile in women of childbearing age

Background and aimsIodine supplementation is advised for women with compromised iodine intake in the preconception period. The purpose of this study was to evaluate the benefits and harms of a supplementary dose of iodine (150 μg/day) for 90 days in women of childbearing age. Materials and methodsNon-pregnant females (n = 38; mean age: 24.1 ± 2.6 years; Range: 20–30) receiving a hall diet were enrolled. Measurements of urinary iodine excretion (UIC), thyroid autoimmunity biomarkers, serum clinical biochemistry profile and serum thyroglobulin were performed at baseline- and after iodine supplementation at 45- and 90 days, respectively. ResultsMedian UICs (μg/L) at baseline and after iodine intervention were 110, 304 and 310, respectively. This coincided with reductions in thyroglobulin, triacylglycerol, HDL-C, LDL-C, LDH, ALP and CPK levels as well as the prevalence of participants with UIC <150 μg/L. One new case of Tg-AB (+), a marked increase the titer of Tg-AB in one participant with TPO-AB (+)/Tg-AB (+) and two cases of increased thyroglobulin were observed after the iodine treatment. ConclusionsThis investigation indicates that in iodine sufficient regions, it might be difficult to maintain maternal iodine adequacy without iodine supplementation. The iodine supplementation was associated with improvement of atherogenic serum index, diminished levels of markers of cellular injury and a 42.1% drop in the prevalence of participants with maternal iodine deficiency. In instances, which screening of thyroid autoimmunity titers and thyroglobulin are not an option, we recommend the administration of iodine in lower dosages to prevent adverse and exaggerated autoimmune reactions.

Thyroid-stimulating hormone is not the primary regulator of thyroid development in euthyroid children and adolescents living in an iodine-replete area.

It is known that there are multiple factors which can affect thyroid gland development during childhood and adolescence. Our aim was to investigate this issue by examining the relationships between age, sex, several anthropometric parameters, pubertal status, thyroid function tests, and iodine intake status with thyroid volume (TV) in children and adolescents. This was a cross-sectional field study conducted in 11 representative cities and villages of Uzbekistan. Six hundred and ten children and adolescents participated. Anthropometric indices and TV were estimated. In addition, thyroid function tests (TFTs) and urinary iodine excretion (UIE) measures were obtained. Median UIE was 151μg/L, thus the studied areas were iodine-sufficient. TFTs fluctuated in both genders during childhood and adolescence and the thyroid growth spurt was observed, in both sexes, at the ages of 12 and 13years, which coincided with the age of menarche in girls. Thyroid volume was positively correlated with body surface area (BSA) (r = 0.800, p < 0.001), age (r = 0.780, p < 0.001), fat-free mass (FFM) (r = 0.797, p < 0.001) and negatively correlated with serum TSH (r = -0.154, p = 0.05). No association between thyroid volume and UIE was observed. In euthyroid children and adolescents living in iodine-replete areas, thyroid gland development appears to follow the pattern of linear growth and displays a growth spurt at the onset of puberty, probably due to the abrupt increase of circulating sex steroids. At this age, TSH does not appear to be the main regulator of thyroid gland development.

Creatinine Excretion as a Determinant of Accelerated Skeletal Muscle Loss with Critical Illness.

The 24-h urinary creatinine excretion rate has been used as an approximation of the skeletal muscle (SM) mass in non-intensive care unit (ICU) settings. The study goal or aim was to determine reductions in SM mass in patients with recurrent critical illness who are admitted to a medical ICU. Retrospective ICU patient records between 2013 and 2015 were reviewed. Inclusion of ICU patients with repeat 24-h urinary creatinine excretion levels at two different ICU admissions done routinely as part of care. The study design is a case series with patients as their own control. Three patients were found to have data on two separate ICU admissions. The reduction in creatinine excretion among ICU patients was correlated with estimated SM mass. All patients had >50% reduction in creatinine excretion and ≥47% reduction in estimated SM mass over 4 months. All patients were bed-bound after the first ICU admission and met the definition of sarcopenia by the second ICU admission; all patients died during the second ICU admission. The final SM mass in all patients was <4 kg m-2. Patients with chronic critical illness admitted to the medical ICU, who become bed bound, can experience up to 50% reduction in SM mass as gleaned from creatinine excretion within 4 months. Low SM mass may predispose patients to increased mortality. Measurement of 24-h urinary creatinine excretion may be a useful ICU biomarker to determine SM mass for diagnostic and prognostic purposes.

Urinary excretion as a function of uranium concentration in bladder cancer patients using kinetic phosphorimetry analyzer

Measurement of urinary excretion is most commonly used as a method of assessing internal contamination due to insoluble nuclides. The pulsed-laser Kinetic Phosphorimetry Analyzer (KPA-11 with analysis range 0.01μg/L up to 50mg/L for Uranium) has been used to determine the Uranium concentration (Uc) in urine samples of three groups of persons; Bladder cancer patients, Healthy and Infants (with age less than two month) and their mothers. The range of Uc excreted in all subjects have been found to be 0.735–3.876μgl-1 with an overall average of 2.00038 μgl-1, 0.856–1.042μgl-1 with an overall average of 0.9464 μgl-1 and 0.505–0.979μgl-1 with an overall average of 0.7742 μgl-1, respectively. The obtained results illustrated that there is statistically significant correlation between Uc and residential area. The obtained Mean values of Uc of the different groups were found to be approximately proportional to age up to 50 years. A noticeable drop is observed for subjects greater than 50 years old. A synthetic urine analysis was chosen in this study to proclaim any concern over biohazards, such as acidity of urine, increasing Amorphous urate, Uric acid, and decreasing Mucous.

Cruciferous Vegetables and Risk of Cancers of the Gastrointestinal Tract.

Cancers of the oropharyngeal tissues, oesophagus, stomach, and colorectum are amongst the most common causes of death from cancer throughout the world. Higher consumption of fruits and vegetables is thought to be protective, and cruciferous vegetables are of particular interest because of their unique role as a source of biologically active glucosinolate breakdown products. A literature review of primary studies and meta-analyses indicates that higher consumption of cruciferous vegetables probably reduces the risk of colorectal and gastric cancers by approximately 8% and 19%, respectively. Some studies support the hypothesis that the protective effect against colorectal cancer is modified by genetic polymorphisms of genes regulating the expression of enzymes of the glutathione S-transferase family, but due to contradictory findings the evidence is currently inconclusive. Despite these promising findings, future epidemiological research on the protective effects of cruciferous plants will depend critically upon accurate measurement of dietary exposure, both to the vegetables themselves, and to their active constituents. The development of sensitive chemical assays has facilitated the measurement of urinary excretion of isothiocyanate metabolites as an objective biomarker of intake, but sampling strategies need to be optimized in order to assess long-term exposures at the population level.

Validation of single measurement of 12-hour urine excretion for estimation of sodium and potassium intake. A longitudinal study.

Evaluation of sodium and potassium intake can be carried out using different methods. Biological markers are able to capture intra and inter-individual variability and are used as separate measurements of consumption. The aim of this study was to test the validity of a single measurement of urinary sodium and potassium excretion as representative of habitual intake. Longitudinal study, federal university. Food consumption data from a sample of adult university students and public servants (25 to 74 years old) were collected through 24-hour records and 12-hour urinary sodium and potassium excretion at five different times over a one-year period. The dietary data were entered into a nutritional research data software system and the sodium and potassium intakes were estimated. The variables were tested for normal distribution using the Kolmogorov-Smirnov test. One-way analysis of variance or the Kruskal-Wallis test was used to evaluate means. Correlations between measurements using Pearson or Spearman coefficients were calculated. The degree of agreement between the five measurements was given by the intraclass correlation coefficient. Satisfactory agreement was found between the five measurements of urinary sodium and potassium excretion over a year, with little variability in consumption. A single measurement of urinary sodium and potassium accurately estimated the usual average consumption of these electrolytes. This can be used in population-based studies.

Measurements of 24-Hour Urinary Sodium and Potassium Excretion

Measurements of 24-Hour Urinary Sodium and Potassium Excretion

National survey of Japanese patients with mevalonate kinase deficiency reveals distinctive genetic and clinical characteristics

Objectives: Mevalonate kinase deficiency (MKD), a rare autosomal recessive autoinflammatory syndrome, is caused by disease-causing variants of the mevalonate kinase (MVK) gene. A national survey was undertaken to investigate clinical and genetic features of MKD patients in Japan.Methods: The survey identified ten patients with MKD. Clinical information and laboratory data were collected from medical records and by direct interviews with patients, their families, and their attending physicians. Genetic analysis and measurement of MVK activity and urinary excretion of mevalonic acid were performed.Results: None of the 10 patients harbored MVK disease-causing variants that are common in European patients. However, overall symptoms were in line with previous European reports. Continuous fever was observed in half of the patients. Elevated transaminase was observed in four of the 10 patients, two of whom fulfilled the diagnostic criteria for hemophagocytic lymphohistiocytosis. About half of the patients responded to temporary administration of glucocorticoids and NSAIDs; the others required biologics such as anti-IL-1 drugs.Conclusion: This is the first national survey of MKD patients in a non-European country. Although clinical symptoms were similar to those reported in Europe, the incidence of continuous fever and elevated transaminase was higher, probably due to differences in disease-causing variants.

Continuously sustained elimination of iodine deficiency: a quarter of a century success in the Islamic Republic of Iran

BackgroundIodine deficiency and related disorders were very common in Iran prior to 1996, when universal salt iodization (USI) was implemented and in 2000 Iran was declared iodine deficiency disorders (IDD) free. The aim of this study was to evaluate the adequacy of iodine intake by Iranian households in all 30 provinces of Iran, a quarter of a century after the intervention.MethodsA total of 18,000 school-aged children (8–10 years with mean 8.7 ± 1 year) were included in this study. Urine samples were collected from all children for measurement of urinary iodine excretion and 1800, 210 and 3000 salt samples were randomly collected from the family kitchen, production site of 73 salt factories and distribution circles of 30 provinces, respectively.ResultsThe median urinary iodine concentration (UIC) of participants was 161 μg/L. The proportion of children with UIC of, 20–49, 50–99 and ≥ 100 μg/L were 10.3, 15.9 and 73.7%, respectively. The mean (± SD) and median salt iodine values were 28.2 (± 12.6) and 31.7 ppm, at the production site, and 31.5 (± 13.6) and 29.6 ppm at the distribution circles, respectively. About 80% of factory salts had more than 20 ppm iodine. 98% of households consumed iodized salt, 80% had appropriate salt storage, and 83% of the household salts contained ≥ 20 ppm.ConclusionsBased on the results of this study, Iranian populations are consuming adequate iodine. The well-maintained and monitored USI program has improved the dietary iodine intakes of the population, and the country has achieved all criteria of a well-controlled IDD program.

Validation of daily urinary creatinine excretion measurement by muscle-creatinine equivalence.

Twenty-four-hour urinary creatinine excretion (24hUCrE) is strongly correlated with skeletal muscle mass (SMM). This study suggests how to exploit the power of the SMM-24hUCrE correlation to assess the accuracy of 24hUCrE measurement. Four hundred and sixty-six men, a subgroup of participants in the 2002-2004 follow-up examination of the Olivetti Heart Study, performed a 24-h urine collection to measure 24hUCrE and underwent bioelectrical impedance analysis to evaluate SMM. Linear regression analysis between 24hUCrE and SMM was used to calculate the muscle-creatinine equivalence and to develop an equation to predict the 24hUCrE depending on SMM. The accuracy of the 24hUCrE measurement was assessed using the change in the SMM-24hUCrE correlation coefficient upon variation in the percentage deviation (%D) between the measured and predicted 24hUCrE. The calculated muscle-creatinine equivalence was 1g of 24hUCrE=22.73kg of SMM. The %Ds and the corresponding SMM-24hUCrE correlation coefficients were as follows: %D=3.0, r=.997; %D=4.7, r=.989; %D=8.1, r=.963; %D=10.5, r=.940; %D=12.6, r=.909; %D=18.9, r=.825; %D=25.8, r=.707; %D=33.5, r=.595; %D=41.4, r=.453. The increase in %D corresponds to a reduced correlation between muscle mass and creatinine excretion, which indicated a poor performance in the measurement of the 24hUCrE. For studies on single individuals, where small variations in 24hUCrE could be significant, a %D up to 12.6% is suggested; on the other hand, a wider %D interval could be acceptable for population studies.

Metabolic Acidosis and Subclinical Metabolic Acidosis in CKD.

Metabolic acidosis is not uncommon in CKD and is linked with bone demineralization, muscle catabolism, and higher risks of CKD progression and mortality. Clinical practice guidelines recommend maintaining serum total CO2 at ≥22 mEq/L to help prevent these complications. Although a definitive trial testing whether correcting metabolic acidosis improves clinical outcomes has not been conducted, results from small, single-center studies support this notion. Furthermore, biologic plausibility supports the notion that a subset of patients with CKD have acid-mediated organ injury despite having a normal serum total CO2 and might benefit from oral alkali before overt acidosis develops. Identifying these individuals with subclinical metabolic acidosis is challenging, but recent results suggest that urinary acid excretion measurements may be helpful. The dose of alkali to provide in this setting is unknown as well. The review discusses these topics and the prevalence and risk factors of metabolic acidosis, mechanisms of acid-mediated organ injury, results from interventional studies, and potential harms of alkali therapy in CKD.

Associations of Biomarker-Calibrated Sodium and Potassium Intakes With Cardiovascular Disease Risk Among Postmenopausal Women.

Studies of the associations of sodium and potassium intakes with cardiovascular disease incidence often rely on self-reported dietary data. In the present study, self-reported intakes from postmenopausal women at 40 participating US clinical centers are calibrated using 24-hour urinary excretion measures in cohorts from the Women's Health Initiative, with follow-up from 1993 to 2010. The incidence of hypertension was positively related to (calibrated) sodium intake and to the ratio of sodium to potassium. The sodium-to-potassium ratio was associated with cardiovascular disease incidence during an average follow-up period of 12 years. The estimated hazard ratio for a 20% increase in the sodium-to-potassium ratio was 1.13 (95% confidence interval (CI): 1.04, 1.22) for coronary heart disease, 1.20 (95% CI: 1.01, 1.42) for heart failure, and 1.11 (95% CI: 1.04, 1.19) for a composite cardiovascular disease outcome. The association with total stroke was not significant, but it was positive for ischemic stroke and inverse for hemorrhagic stroke. Aside from hemorrhagic stroke, corresponding associations of cardiovascular disease with sodium and potassium jointly were positive for sodium and inverse for potassium, although some were not statistically significant. Specifically, for coronary heart disease, the hazard ratios for 20% increases were 1.11 (95% CI: 0.95, 1.30) for sodium and 0.85 (95% CI: 0.73, 0.99) for potassium; and corresponding values for heart failure were 1.36 (95% CI: 1.02, 1.82) for sodium and 0.90 (95% CI: 0.69, 1.18) for potassium.

Intrarenal signaling mediated by CCK plays a role in salt intake-induced natriuresis.

The natriuretic hormone CCK exhibits its gene transcripts in total kidney extracts. To test the possibility of CCK acting as an intrarenal mediator of sodium excretion, we examined mouse kidneys by 1) an in situ hybridization technique for CCK mRNA in animals fed a normal- or a high-sodium diet; 2) immuno-electron microscopy for the CCK peptide, 3) an in situ hybridization method and immunohistochemistry for the CCK-specific receptor CCKAR; 4) confocal image analysis of receptor-mediated Ca2+ responses in isolated renal tubules; and 5) metabolic cage experiments for the measurement of urinary sodium excretion in high-salt-fed mice either treated or untreated with the CCKAR antagonist lorglumide. Results showed the CCK gene to be expressed intensely in the inner medulla and moderately in the inner stripe of the outer medulla, with the expression in the latter being enhanced by high sodium intake. Immunoreactivity for the CCK peptide was localized to the rough endoplasmic reticulum of the medullary interstitial cells in corresponding renal regions, confirming it to be a secretory protein. Gene transcripts, protein products, and the functional activity for CCKAR were consistently localized to the late proximal tubule segments (S2 and S3) in the medullary rays, and the outer stripe of the outer medulla. Lorglumide significantly diminished natriuretic responses of mice to a dietary sodium load without altering the glomerular filtration rate. These findings suggest that the medullary interstitial cells respond to body fluid expansion by CCK release for feedback regulation of the late proximal tubular reabsorption.

Applying recovery biomarkers to calibrate self-report measures of sodium and potassium in the Hispanic Community Health Study/Study of Latinos.

Measurement error in assessment of sodium and potassium intake obscures associations with health outcomes. The level of this error in a diverse US Hispanic/Latino population is unknown. We investigated the measurement error in self-reported dietary intake of sodium and potassium and examined differences by background (Central American, Cuban, Dominican, Mexican, Puerto Rican and South American). In 2010-2012, we studied 447 participants aged 18-74 years from four communities (Miami, Bronx, Chicago and San Diego), obtaining objective 24-h urinary sodium and potassium excretion measures. Self-report was captured from two interviewer-administered 24-h dietary recalls. Twenty percent of the sample repeated the study. We examined bias in self-reported sodium and potassium from diet and the association of mismeasurement with participant characteristics. Linear regression relating self-report with objective measures was used to develop calibration equations. Self-report underestimated sodium intake by 19.8% and 20.8% and potassium intake by 1.3% and 4.6% in men and women, respectively. Sodium intake underestimation varied by Hispanic/Latino background (P<0.05) and was associated with higher body mass index (BMI). Potassium intake underestimation was associated with higher BMI, lower restaurant score (indicating lower consumption of foods prepared away from home and/or eaten outside the home) and supplement use. The R2 was 19.7% and 25.0% for the sodium and potassium calibration models, respectively, increasing to 59.5 and 61.7% after adjusting for within-person variability in each biomarker. These calibration equations, corrected for subject-specific reporting error, have the potential to reduce bias in diet-disease associations within this largest cohort of Hispanics in the United States.

Genetic variation underlying renal uric acid excretion in Hispanic children: the Viva La Familia Study

BackgroundReduced renal excretion of uric acid plays a significant role in the development of hyperuricemia and gout in adults. Hyperuricemia has been associated with chronic kidney disease and cardiovascular disease in children and adults. There are limited genome-wide association studies associating genetic polymorphisms with renal urate excretion measures. Therefore, we investigated the genetic factors that influence the excretion of uric acid and related indices in 768 Hispanic children of the Viva La Familia Study.MethodsWe performed a genome-wide association analysis for 24-h urinary excretion measures such as urinary uric acid/urinary creatinine ratio, uric acid clearance, fractional excretion of uric acid, and glomerular load of uric acid in SOLAR, while accounting for non-independence among family members.ResultsAll renal urate excretion measures were significantly heritable (p <2 × 10−6) and ranged from 0.41 to 0.74. Empirical threshold for genome-wide significance was set at p <1 × 10−7. We observed a strong association (p < 8 × 10−8) of uric acid clearance with a single nucleotide polymorphism (SNP) in zinc finger protein 446 (ZNF446) (rs2033711 (A/G), MAF: 0.30). The minor allele (G) was associated with increased uric acid clearance. Also, we found suggestive associations of uric acid clearance with SNPs in ZNF324, ZNF584, and ZNF132 (in a 72 kb region of 19q13; p <1 × 10−6, MAFs: 0.28–0.31).ConclusionFor the first time, we showed the importance of 19q13 region in the regulation of renal urate excretion in Hispanic children. Our findings indicate differences in inherent genetic architecture and shared environmental risk factors between our cohort and other pediatric and adult populations.

Prevalence of thyroid disorders inelderly people in Germany. A screening study in a country withendemic goitre.

In a screening study on people of working age the prevalence of morphological thyroid disorders was 33.1 %. It is not known precisely whether this further increases after retirement. The present study aimed to establish whether the increase in the prevalence of morphological and functional thyroid disorders continues beyond working age in elderly citizens. 223 participants were recruited in an institute for geriatric rehabilitative medicine. All patients were screened by thyroid ultrasound, measurement of serum levels of thyroid hormones and thyroid related autoantibodies as well as measurement of urinary iodine excretion. The median thyroid volume was 17 ml (range 4-41 ml) in men and 16 ml (range 0.4-73 ml) in women. 27/59 (46 %) of the men (median age [range]: 77 [58-87] years) and 85/139 (61 %) of the women (median age [range]: 77 [52-97] years), or a total of 112/198 (57 %) residents, showed morphological thyroid abnormalities. There was no clear increase with age. 85 % of the participants without a history of thyroid treatment were euthyroid. 12 % showed a subclinical hyperthyroidism whereas 1 % showed a biochemically manifest hyperthyroidism. 2 % were biochemically hypothyroid. Tg-antibodies was elevated in 10 (5 %) and TPO-antibodies in 18 (9 %) of the patients. Median iodine excretion was 129 µg/l. 41.5 % of the patients showed iodine excretion values below 100 µg/l whereas only 7 % of the patients showed a severe iodine deficiency with an excretion below 50 µg/l. Compared to a previously described population of working age, the prevalence of morphological thyroid disorders does not further increase above the age of 65; thyroid function abnormalities in this iodine sufficient screening population were relatively rare.

Markers of oxidative stress in obese men with and without hypertension

Objectives: The aim of our study was to investigate if the 24-hour excretion of the urinary markers for oxidative stress to DNA and RNA, measured as 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydro-guanosine (8-oxoGuo), respectively, were increased in obese individuals with or without hypertension compared to lean controls.Methods: A total of 63 obese hypertensive men (obeseHT), 40 obese normotensive men (obeseNT) and 27 lean normotensive men (leanNT) were included in the study. Body mass index (BMI) was between 20.0 and 24.9 kg/m2 in leanNT participants and ≥30 kg/m2 in obese participants. Hypertension was defined as a mean 24-hour systolic ambulatory blood pressure (AMBP) ≥ 130 mmHg or a mean 24-hour diastolic AMBP ≥80 mmHg and normotension as mean 24-hour AMBP <130/80 mmHg. Twenty-four hour urinary 8-oxoGuo and 8-oxodG excretion (nmol/24 h) were measured by a validated liquid chromatography-tandem mass spectrometry method (UPLC-MS/MS).Results: Urinary 8-oxoGuo excretion was (median and [interquartile range]) 30.8 [27.8–32.2] nmol/24 h in leanNT, 36.8 [31.3–40.2] nmol/24 h in obeseNT and 40.6 [31.7–48.5] nmol/24 h in obeseHT. The difference was statistically significant (p = .002) and post hoc tests showed a significant difference between leanNT and obeseHT (p = .001) as well as obeseNT (p = .002), whereas the two obese groups did not differ (p = .6). No statistically significant differences in 8-oxodG concentrations were observed between the three groups (p = .3).Conclusion: The measurement of urinary excretion of 8-oxoGuo suggests that obesity in men, but not hypertension, is associated with increased oxidative damage to RNA.