Machine Learning Prediction of Biomarkers from SNPs and of Disease Risk from Biomarkers in the UK Biobank

We use UK Biobank data to train predictors for 65 blood and urine markers such as HDL, LDL, lipoprotein A, glycated haemoglobin, etc. from SNP genotype. For example, our Polygenic Score (PGS) predictor correlates ∼0.76 with lipoprotein A level, which is highly heritable and an independent risk factor for heart disease. This may be the most accurate genomic prediction of a quantitative trait that has yet been produced (specifically, for European ancestry groups). We also train predictors of common disease risk using blood and urine biomarkers alone (no DNA information); we call these predictors biomarker risk scores, BMRS. Individuals who are at high risk (e.g., odds ratio of >5× population average) can be identified for conditions such as coronary artery disease (AUC∼0.75), diabetes (AUC∼0.95), hypertension, liver and kidney problems, and cancer using biomarkers alone. Our atherosclerotic cardiovascular disease (ASCVD) predictor uses ∼10 biomarkers and performs in UKB evaluation as well as or better than the American College of Cardiology ASCVD Risk Estimator, which uses quite different inputs (age, diagnostic history, BMI, smoking status, statin usage, etc.). We compare polygenic risk scores (risk conditional on genotype: PRS) for common diseases to the risk predictors which result from the concatenation of learned functions BMRS and PGS, i.e., applying the BMRS predictors to the PGS output.

Differential urinary proteins to diagnose coronary heart disease based on iTRAQ quantitative proteomics

Coronary artery disease (CAD) is a manifestation of systemic atherosclerotic disease. It is assessed by intervention or traditional scoring risk factors. Diagnosis is limited by inaccurate and invasive methods. Developing noninvasive methods to screen for the risk of CAD is a major challenge. We aimed to identify urinary proteins associated with CAD. We utilized iTRAQ labeling followed by 2D LC-MS/MS to compare the urinary proteome of CAD patients to healthy cohorts. The multiple reaction monitoring (MRM) was used to verify the differential proteins. ROC analysis based on MRM data was used to evaluate the diagnostic application. A total of 876 proteins were quantified, and 100 differential proteins were found. Functional analysis revealed that the differential proteins were mainly associated with Liver X Receptor/Retinoid X Receptor (LXR/RXR) pathway activation, atherosclerosis signaling, production of nitric oxide and reactive oxygen species, and the top upstream regulator of the differential proteins by IPA analysis indicated to the APOE. Nineteen differential proteins were verified by MRM analysis. ROC based on MRM data revealed that the combination of two proteins (APOD and TFF1) could diagnose CAD with 85% sensitivity and 99% specificity (AUC 0.95). The urinary proteome might reflect the pathophysiological changes in CAD and be used for the clinical study of CAD.

Significance of urinary 11-dehydro-thromboxane B2 in age-related diseases: Focus on atherothrombosis

Platelet activation plays a key role in atherogenesis and atherothrombosis. Biochemical evidence of increased platelet activation in vivo can be reliably obtained through non-invasive measurement of thromboxane metabolite (TXM) excretion. Persistent biosynthesis of TXA₂ has been associated with several ageing-related diseases, including acute and chronic cardio-cerebrovascular diseases and cardiovascular risk factors, such as cigarette smoking, type 1 and type 2 diabetes mellitus, obesity, hypercholesterolemia, hyperhomocysteinemia, hypertension, chronic kidney disease, chronic inflammatory diseases. Given the systemic nature of TX excretion, involving predominantly platelet but also extraplatelet sources, urinary TXM may reflect either platelet cyclooxygenase-1 (COX-1)-dependent TX generation or COX-2-dependent biosynthesis by inflammatory cells and/or platelets, or a combination of the two, especially in clinical settings characterized by low-grade inflammation or enhanced platelet turnover. Although urinary 11-dehydro-TXB₂ levels are largely suppressed with low-dose aspirin, incomplete TXM suppression by aspirin predicts the future risk of vascular events and death in high-risk patients and may identify individuals who might benefit from treatments that more effectively block in vivo TX production or activity. Several disease-modifying agents, including lifestyle intervention, antidiabetic drugs and antiplatelet agents besides aspirin have been shown to reduce TX biosynthesis. Taken together, these aspects may contribute to the development of promising mechanism-based therapeutic strategies to reduce the progression of atherothrombosis. We intended to critically review current knowledge on both the pathophysiological significance of urinary TXM excretion in clinical settings related to ageing and atherothrombosis, as well as its prognostic value as a biomarker of vascular events.

Urinary miRNA-377 and miRNA-216a as biomarkers of nephropathy and subclinical atherosclerotic risk in pediatric patients with type 1 diabetes

BACKGROUND

Urinary microRNAs (miRNAs) play a role in the pathogenesis of chronic kidney disease (CKD).

AIM

To identify the expression of urinary miR-377 and miR-216a in 50 children and adolescents with type 1 diabetes (T1DM) compared with 50 healthy controls and assess their relation to the degree of albuminuria, glycemic control and carotid intimal thickness (CIMT) as an index of atherosclerosis.

METHODS

Diabetic subjects were divided into normoalbuminuric and microalbuminuric groups according to urinary albumin creatinine ration (UACR). Urinary miRNAs were assessed using real time polymerase chain reaction. CIMT was measured using high resolution carotid ultrasound.

RESULTS

The expression of urinary miR-377 was significantly higher in patients with microalbumiuria (median, 3.8) compared with 2.65 and 0.98 in normoalbuminic patients and healthy controls, respectively (p<0.05). Urinary miR-216a was significantly lower in all patients with type 1 diabetes and the lowest levels were among the microalbumiuric group. Significant positive correlations were found between urinary miR-377 and HbA1C, UACR and CIMT while urinary miR-216a was negatively correlated to these variables.

CONCLUSIONS

Urinary miR-377 and miR-216a can be considered early biomarkers of nephropathy in pediatric type 1 diabetes. Their correlation with CIMT provides insights on the subclinical atherosclerotic process that occurs in diabetic nephropathy.

Surface-enhanced Raman scattering analysis of urine from deceased donors as a prognostic tool for kidney transplant outcome

We report the utility of surface-enhanced Raman scattering (SERS) analysis of urine from deceased donors for prognosis of kidney transplant outcomes. Iodide-modified silver nanoparticles were used as the enabler for sensitive measurements of urine proteins. Principal component analysis (PCA) and linear discriminant analysis (LDA) were employed for the statistical analysis of the SERS data. Thirty urine samples in three classes were analysed. The ATN class consists of donors whose kidneys had acute tubular necrosis (ATN), the most common type of acute kidney injury (AKI) with high risk of poor graft performance in recipients, yet yielded acceptable transplant outcome. The DGF class is comprised of donors whose kidney had delayed graft function (DGF) in recipients. The control class includes donors whose kidneys did not have donor ATN or recipient DGF. We show a sensitivity of more than 90 % in differentiating the ATN class from the DGF and control classes. Our methodology can thus help clinicians choose kidneys in the high-risk ATN category for transplant which would otherwise be discarded. Our research is impactful in that it could serve as a valuable guidance to expand the deceased donor pool to include those perceived as high-risk AKI type based on common urinary biomarkers. Picutre: Scheme of SERS analysis of urine samples from deceased donors for kidney transplant outcome indication.

The influence of different diets on metabolism and atherosclerosis processes-A porcine model: Blood serum, urine and tissues 1H NMR metabolomics targeted analysis

The global epidemic of cardiovascular diseases leads to increased morbidity and mortality caused mainly by myocardial infarction and stroke. Atherosclerosis is the major pathological process behind this epidemic. We designed a novel model of atherosclerosis in swine. Briefly, the first group (11 pigs) received normal pig feed (balanced diet group-BDG) for 12 months, the second group (9 pigs) was fed a Western high-calorie diet (unbalanced diet group-UDG) for 12 months, the third group (8 pigs) received a Western type high-calorie diet for 9 months later replaced by a normal diet for 3 months (regression group-RG). Clinical measurements included zoometric data, arterial blood pressure, heart rate and ultrasonographic evaluation of femoral arteries. Then, the animals were sacrificed and the blood serum, urine and skeletal muscle tissue were collected and 1H NMR based metabolomics studies with the application of fingerprinting PLS-DA and univariate analysis were done. Our results have shown that the molecular disturbances might overlap with other diseases such as onset of diabetes, sleep apnea and other obesity accompanied diseases. Moreover, we revealed that once initiated, molecular changes did not return to homeostatic equilibrium, at least for the duration of this experiment.

Polyphenol intake from a Mediterranean diet decreases inflammatory biomarkers related to atherosclerosis: a substudy of the PREDIMED trial

High dietary polyphenol intake is associated with reduced all-cause mortality and a lower incidence of cardiovascular events. However, the mechanisms involved are not fully understood. The aim of the present substudy of the PREvención con DIetaMEDiterránea (Prevention with Mediterranean diet; PREDIMED) trial was to analyse the relationship between polyphenol intake measured by total urinary polyphenol excretion (TPE), and circulating inflammatory biomarkers and cardiovascular risk factors in elderly individuals. A substudy of 1139 high-risk participants was carried out within the PREDIMED trial. The subjects were randomly assigned to a low-fat control diet or to two Mediterranean diets, supplemented with either extra-virgin olive oil or nuts. Dietary intake, anthropometric data, clinical and laboratory assessments, including inflammatory biomarkers, and urinary TPE were measured at baseline and after the one-year intervention. Participants in the highest tertile of changes in urinary TPE (T3) showed significantly lower plasma levels of inflammatory biomarkers [vascular cell adhesion molecule 1 (VCAM-1) (-9.47 ng ml-1 ), intercellular adhesion molecule 1 (-14.71 ng ml-1 ), interleukin 6 (-1.21 pg ml-1 ), tumour necrosis factor alpha (-7.05 pg ml-1 ) and monocyte chemotactic protein 1 (-3.36 pg ml-1 )] than those inthe lowest tertile (T1, P < 0.02; all). A significant inverse correlation existed between urinary TPE and the plasma concentration of\VCAM-1 (r = -0.301; P < 0.001). In addition, systolic and diastolic blood pressure (BP) decreased and plasma high-density lipoprotein cholesterol increased in parallel with increasing urinary TPE (T3 vs. T1) (P < 0.005 and P = 0.004, respectively). Increases in polyphenol intake measured as urinary TPE are associated with decreased inflammatory biomarkers, suggesting a dose-dependent anti-inflammatory effect of polyphenols. In addition, high polyphenol intake improves cardiovascular risk factors- mainly BP and the lipid profile.

The Urinary Phosphate to Serum Fibroblast Growth Factor 23 Ratio Is a Useful Marker of Atherosclerosis in Early-Stage Chronic Kidney Disease

Background

Fibroblast growth factor 23 (FGF23) regulates mineral homeostasis. In developed renal dysfunction, FGF23 levels increase to maintain the phosphate excretion capacity. However, in diabetic patients with early-stage renal impairment, the FGF23 elevation is not very sensitive. We hypothesized that urinary phosphate (U-P)/serum FGF23 ratio would theoretically be an index that reflects the number of nephrons (nephron index). In this study, we determined whether the nephron index would be associated with renal function and vascular diseases in diabetic patients.

Methods

In total, 142 patients with diabetes mellitus were enrolled. The nephron index was calculated using the following formula: U-P (mg/day)/ serum FGF23 (pg/ml).

Results

The mean age was 63 ± 11 years and eGFR levels were 79.5 ± 25.4 ml/min/1.73 m², respectively. Thirty patients had a medical history of macroangiopathy. The Nephron index was significantly decreased in subjects with macroangiopathy compared with those without macroangiopathy. A multivariate analysis of risk factors for macroangiopathy revealed that duration of diabetes, eGFR, and nephron index were significantly associated with a higher frequency of arteriosclerotic disease.

Conclusion

These findings suggest that a decrease in nephron index reflects early-stage renal impairment and is an independent risk factor of macroangiopathy in diabetic patients.

Urine Albumin-to-Creatinine Ratio: A Marker of Early Endothelial Dysfunction in Youth

CONTEXT

The urine albumin-to-creatinine ratio (UACR) is a useful predictor of cardiovascular (CV) events in adults. Its relationship to vascular function in children is not clear.

OBJECTIVE

We investigated whether UACR was related to insulin resistance and endothelial function, a marker of subclinical atherosclerosis, in adolescents across the spectrum of glucose regulation.

PARTICIPANTS

Participants were 58 adolescents: 13 normal weight (NW), 25 overweight with normal glucose tolerance (OW-NGT), and 20 overweight with prediabetes (OW-PreD).

INTERVENTIONS

Interventions included oral glucose tolerance test, hyperinsulinemic-euglycemic clamp with determination of insulin sensitivity (IS), endothelial function assessment by peripheral arterial tonometry determination of the reactive hyperemia index (RHI), body composition (dual-energy x-ray absorptiometry), and abdominal fat distribution (magnetic resonance imaging).

PRIMARY OUTCOME MEASURE

Fasting UACR was determined.

RESULTS

The 3 groups did not differ with respect to age, sex, or Tanner stage. The NW group had significantly lower percent body fat, higher IS (10.4 ± 0.9, 3.5 ± 0.6, and 2.1 ± 0.2 mg/kg/min per μU/mL; P < .001), and higher RHI (1.84 ± 0.1, 1.56 ± 0.1, and 1.56 ± 0.1, P = .04) than the OW-NGT and OW-PreD groups, respectively. lnUACR was related to percent body fat (r = 0.4, P = .001), RHI (r = -0.33, p = .01), and IS (r = -0.27, P = .043). In multiple regression analysis with lnUACR as the dependent variable and RHI, percent body fat, age, sex, race, systolic blood pressure, cholesterol, glycated hemoglobin, and IS as independent variables, RHI (β = -0.3, P = .045) and sex (β = 0.31, P = .06) contributed to the variance in UACR (R(2) = 0.35, P = .02).

CONCLUSIONS

UACR is an early marker of endothelial dysfunction in youth, independent of glycemia. Endothelial dysfunction may mediate the link between obesity-related insulin resistance and early microalbuminuria.

Advances in urinary protein biomarkers for urogenital and non-urogenital pathologies

The discovery of protein biomarkers that reflect the biological state of the body is of vital importance to disease management. Urine is an ideal source of biomarkers that provides a non-invasive approach to diagnosis, prognosis and prediction of diseases. Consequently, the study of the human urinary proteome has increased dramatically over the last 10 years, with many studies being published. This review focuses on urinary protein biomarkers that have shown potential, in initial studies, for diseases affecting the urogenital tract, specifically chronic kidney disease and prostate cancer, as well as other non-urogenital pathologies such as breast cancer, diabetes, atherosclerosis and osteoarthritis. PubMed was searched for peer-reviewed literature on the subject, published in the last 10 years. The keywords used were "urine, biomarker, protein, and/or prostate cancer/breast cancer/chronic kidney disease/diabetes/atherosclerosis/osteoarthritis". Original studies on the subject, as well as a small number of reviews, were analysed including the strengths and weaknesses, and we summarized the performance of biomarkers that demonstrated potential. One of the biggest challenges found is that biomarkers are often shared by several pathologies so are not specific to one disease. Therefore, the trend is shifting towards implementing a panel of biomarkers, which may increase specificity. Although there have been many advances in urinary proteomics, these have not resulted in similar advancements in clinical practice due to high costs and the lack of large data sets. In order to translate these potential biomarkers to clinical practice, vigorous validation is needed, with input from industry or large collaborative studies.

[Features of Urine Biomineralization in Long-Livers]

BACKGROUND

The increasing number of long-livers in the developed countries indicates the demand for clarification of the body vital systems' functioningfeatures which allow the long-livers to prolong their active involvement in social life.

OBJECTIVE

Aim of our study/research was to define a functional condition of urinary system in long-livers using the new diagnostic technology which analyses the structures of biological liquid at its phase transition in a solid state.

METHODS

A case series study was held. All long-livers suffered from atherosclerosis and its complications as well as from associated diseases. An exclusion criterion was acute conditions. The creatinine level in blood serum, indicators of common urine analysis and features of urine facies (using cuneiform dehydration) were defined.

RESULTS

Participants included 60 long-livers (mean age 87.34±4.17 years) who were passing clinical laboratory tests at in-patient department of gerontological hospital. In urine facies of 41 (68.3%) long-livers a phenomenon of salt crystals distribution was identified. It presents the concentration of anisotropic salt crystals in the form of a ring in a regional facies zone. The tenfold increase in concentration of calcium and double increase in concentration of phosphorus in comparison with the central zone was detected in long-livers with a higher percent sulphur in the regional zone of urinefacies.

CONCLUSION

The urine facies of the majority of long-livers have signs of age structure formation associated with a specific distribution of anisotropic salt crystals which fix detritus in its inert form to block the autointoxication.

Poor lung function has inverse relationship with microalbuminuria, an early surrogate marker of kidney damage and atherosclerosis: the 5th Korea National Health and Nutrition Examination Survey

Background

Despite epidemiological evidences of relationship between poor lung function and atherosclerosis, the relationship between poor lung function and microalbuminuria (MAU), an early surrogate marker of both kidney damage and atherosclerosis, is not well understood. Hence, we plan to investigate the relationship between poor lung function and MAU using multivariate models to adjust for other atherogenic risk factors.

Methods

We used data from the 5^th Korean National Health and Nutrition Examination Survey. Poor lung function is determined by spirometric measurement, primarily through estimation of the forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). Declines in the percent predicted FVC (<80%) and in the FEV₁/FVC ratio (<0.7) are defined as restrictive and obstructive patterns, respectively. Urine albumin to urine creatinine levels ratio (UACR) were measured in spot urine samples. MAU was defined as UACR >30 mg/g.

Results

Inverse relationship was observed between lung function and UACR. In an age-adjusted regression model, the regression coefficient (B) of 10% lower FVC was 11.09 in men (P = 0.002), which remained significant after adjustment for SBP, FBG, triglyceride level, BMI, smoking history, and heavy alcohol consumption (B = 7.52, P = 0.043). When the restrictive pattern was compared to the normal pattern, the odds ratios (OR) (95% confidence interval, 95%CI) for MAU were 1.90 (1.32–2.72) in men, after adjustment for age, hypertension, diabetes mellitus, triglyceride level, obesity, smoking history, physical activity, and heavy alcohol consumption.

Conclusions

Our study, the first investigation in Asia, demonstrated that the restrictive pattern is related to MAU in men. Furthermore, there was linear relationship between lower FVC and UACR. Thus, our current study suggests that poor lung function, particularly the restrictive pattern, is related to kidney damage as well as atherosclerosis.

Racial differences in urinary F2-isoprostane levels and the cross-sectional association with BMI

Levels of four urinary F(2)-isoprostanes (F(2)-IsoPs) were examined in a large sample of the Insulin Resistance Atherosclerosis Study (IRAS) multiethnic cohort: 237 African Americans (AAs), 342 non-Hispanic whites (NHWs), and 275 Hispanic whites (HWs). F(2)-IsoP isomers - iPF2a-III, 2,3-dinor-iPF2a-III, iPF2a-VI, and 8,12-iso-iPF2a-VI - were measured in 854 urine samples using liquid chromatography with tandem mass spectrometry detection. In AAs, levels of all four F(2)-IsoPs were lower compared with NHWs and HWs (P values <0.05). When stratified by BMI, this gap was not observed among participants with normal BMI but appeared among overweight participants and increased among obese participants. Examining the slopes of the associations between BMI and F(2)-IsoPs showed no association between these variables among AAs (P values >0.2), and positive associations among whites (P values <0.05). Taking into account that positive cross-sectional associations between systemic F(2)-IsoP levels and BMI have been consistently demonstrated in many study populations, the lack of such an association among AAs reveals a new facet of racial/ethnic differences in obesity-related risk profiles.

Urinary F2-isoprostanes, obesity, and weight gain in the IRAS cohort

Obesity has been associated with increased F(2)-isoprostane (F(2)-IsoP) levels cross-sectionally. However, the prospective association may be inverse, based on our earlier finding that elevated urinary F(2)-IsoP levels predict lower risk of diabetes. This earlier finding led us to hypothesize that urinary F(2)-IsoPs reflect the intensity of oxidative metabolism and as such predict lower risk of both diabetes and weight gain. We examined cross-sectional relationships with obesity and prospective relationships with weight gain using the data from 299 participants of the Insulin Resistance Atherosclerosis Study (IRAS), all of whom were free of diabetes at baseline. Four urinary F(2)-IsoPs were assayed in stored baseline urine samples using liquid chromatography with tandem mass spectrometry: iPF(2α)-III, 2,3-dinor-iPF(2α)-III, iPF(2α)-VI, and 8,12-iso-iPF(2α)-VI (F(2)-IsoP 1-4, respectively). Baseline F(2)-IsoPs were positively associated with baseline measures of obesity; the strongest associations were found with two F(2)-IsoPs: odds ratios (95% confidence intervals) for overall and abdominal obesity were 1.74 (1.26-2.40) and 1.63 (1.18-2.24) for F(2)-IsoP2 and 1.47 (1.12-1.94) and 1.64 (1.22-2.20) for F(2)-IsoP4. F(2)-IsoP2 showed the strongest and significant inverse association with weight gain during the 5-year follow-up period: increase in F(2)-IsoP2 equal to 1 s.d. was associated with 0.90 kg lower weight gain (P = 0.02) and the odds ratios for relative (≥5%) and absolute (≥5 kg) weight gain were 0.67 (0.47-0.96) and 0.57 (0.37-0.87), respectively. The other three F(2)-IsoPs were consistently inversely associated with weight gain, although not significantly, suggesting that different F(2)-IsoPs vary in their ability to detect the association with weight gain.

Diurnal salivary cortisol and urinary catecholamines are associated with diabetes mellitus: the Multi-Ethnic Study of Atherosclerosis

The objective was to examine the cross-sectional association of diurnal salivary cortisol curve components and urinary catecholamines with diabetes status. Up to 18 salivary cortisol samples over 3 days and overnight urinary catecholamines were collected from 1002 participants in the Multi-Ethnic Study of Atherosclerosis. Diabetes was defined as a fasting blood glucose of at least 126 mg/dL or medication use. Cortisol curve measures included awakening cortisol, cortisol awakening response, early decline, late decline, and cortisol area under the curve (AUC). Urinary catecholamines included epinephrine, norepinephrine, and dopamine. Participants with diabetes had significantly lower cortisol awakening response (β = -0.19; 95% confidence interval [CI], -0.34 to -0.04) than those without diabetes in multivariable models. Whereas men with diabetes had a nonsignificant trend toward lower total AUC (β = -1.56; 95% CI, -3.93 to 0.80), women with diabetes had significantly higher total AUC (β = 2.62; 95% CI, 0.72 to 4.51) (P = .02 for interaction) compared with those without diabetes. Men but not women with diabetes had significantly lower urinary catecholamines compared with those without diabetes (P < .05). Diabetes is associated with neuroendocrine dysregulation, which may differ by sex. Further studies are needed to determine the role of the neuroendocrine system in the pathophysiology of diabetes.

Relationship between visceral fat accumulation and urinary albumin-creatinine ratio in middle-aged Japanese men

OBJECTIVE

Chronic kidney disease including microalbuminuria relates to cardiovascular disease (CVD). Microalbuminuria is also known to be a marker of generalized endothelial dysfunction. The metabolic syndrome which encompasses visceral fat accumulation and various metabolic disorders, has also an increase in albuminuria and relates to CVD. However, the relationship between visceral fat accumulation and albuminuria remains to be defined. The present study investigated the relationship between visceral fat accumulation and urinary albumin-creatinine ratio (UACR) in Japanese men.

METHODS

This study group comprised 1990 Japanese male subjects, who were employees of a city office, had undergone annual health check-up. Urinary albumin was collected from a single spot urine specimen collected anytime between morning and afternoon. Visceral fat area was estimated (eVFA) by the bioelectrical impedance analysis method.

RESULTS

Log-UACR correlated with age, log-body mass index (BMI), log-waist circumference (WC), log-eVFA, log-adiponectin, blood pressure, serum lipids and hemoglobin A1c (HbA1c). Stepwise multiple regression analysis identified log-eVFA, as well as HbA1c, blood pressure, log-TG, and age, as a significant determinant of log-UACR. Moreover, subjects with eVFA > or = 100 cm(2) had significantly higher UACR than those with eVFA <100 cm(2), irrespective of BMI. UACR was significantly worse in subjects with high numbers of metabolic risk factors, and moreover in subjects with eVFA > or = 100 cm(2) than in those with eVFA <100 cm(2).

CONCLUSION

These results suggested that visceral fat accumulation is associated with an increase in UACR. Evaluation of both visceral fat accumulation and urinary albumin may be important for preventing atherosclerotic diseases.

Association of urinary 15-F2t-isoprostane level with oxygen desaturation and carotid intima-media thickness in nonobese sleep apnea patients

Obstructive sleep apnea (OSA) is characterized by recurrent apnea during sleep that may unbalance oxidative stress, increasing atherosclerosis. Among oxidative stress markers, 15-F(2t)-isoprostane is considered one of the most sensitive and specific metabolites of lipid peroxidation. To explore the relationship between urinary 15-F(2t)-isoprostane with sleep apnea severity and carotid modifications in nonobese OSA patients, 31 nonobese sleep apnea patients were studied, along with 10 lean subjects without OSA. Patients were assessed by polysomnography, blood pressure measurement, and ultrasonography to determine the carotid intima-media thickness (IMT). Urinary 15-F(2t)-isoprostanes were measured by liquid chromatography-tandem mass spectrometry. Urinary 15-F(2t)-isoprostane concentrations were increased in severe OSA patients compared to control subjects (20.2+/-7.3 vs 12.3+/-2.8 ng/mmol creatinine; P=0.020). Mean carotid IMT was correlated with 15-F(2t)-isoprostane (r=0.532; P<0.001) and with the apnea-hypopnea index (r=0.345; P=0.029). 15-F(2t)-Isoprostane level was related to the night time spent at SaO(2)<90% (r=0.478; P=0.002), the apnea-hypopnea index (r=0.465; P=0.003), and the mean nocturnal SaO(2) (r=-0.424; P=0.007). These results showed a relationship between lipid peroxidation, carotid intima-media thickness, and intermittent hypoxia in nonobese OSA patients, thus reinforcing the hypothesis that oxidative stress could be involved in the early atherosclerotic process.

Albuminuria and peripheral arterial disease: results from the multi-ethnic study of atherosclerosis (MESA)

BACKGROUND

The association of albuminuria with cardiovascular disease (CVD) is increasingly recognized, but its association with peripheral arterial disease (PAD) is not well characterized in subjects with or without diabetes.

METHODS

Using data from the Multi-Ethnic Study of Atherosclerosis, a cohort free of clinical vascular disease, we analyzed the cross-sectional association between albuminuria and PAD in diabetic and nondiabetic subjects. A spot urine albumin-creatinine ratio (ACR) was used to define albuminuria in two ways: presence or absence of albuminuria and the degree of albuminuria (no albuminuria defined as urine ACR<17 mg/g for men and <25mg/g for women, microalbuminuria as urine ACR 17 to 249 mg/g for men and 25 to 334 mg/g for women, and macroalbuminuria as urine ACR> or =250 mg/g for men and > or =355 mg/g for women). PAD was defined by ankle-brachial index (ABI)<0.9.

RESULTS

Among the 6760 subjects, aged 45-84 years, 326 (4.8%) had prevalent PAD. Eight hundred and thirteen (12.0%) subjects had microalbuminuria and 100 (1.5%) had macroalbuminuria. Among diabetic subjects, those with albuminuria (micro- and macroalbuminuria combined) were 1.90 times more likely to have PAD (95% CI: 1.19-3.04) than those with no albuminuria. After adjusting for CVD risk factors, the odds ratio modestly attenuated to 1.65 (95% CI: 1.00-2.74). For nondiabetic subjects, there were no statistically significant associations observed in the univariable and multivariable analyses. The degree of albuminuria was not associated with PAD in either diabetic or nondiabetic subjects.

CONCLUSIONS

The presence, but not magnitude of albuminuria, is an important risk factor for PAD in diabetic but not in nondiabetic subjects.

Mild elevations of urine albumin excretion are associated with atherogenic lipoprotein abnormalities in the Multi-Ethnic Study of Atherosclerosis (MESA)

OBJECTIVE

Elevated urine albumin excretion is an established risk factor for cardiovascular disease. Increased cardiovascular risk may be partly mediated by abnormalities in lipoprotein metabolism. We examined cross-sectional associations of urine albumin-creatinine ratio (ACR) with standard lipid measurements and with lipoprotein particle concentrations measured by nuclear magnetic resonance (NMR) in the Multi-Ethnic Study of Atherosclerosis.

METHODS AND RESULTS

Among 5633 participants who were not using lipid-lowering medications, greater ACR was associated with greater triglyceride concentration and lesser high density lipoprotein cholesterol concentration (women only), but not with low density lipoprotein (LDL) cholesterol calculated using conventional methods. In contrast, unadjusted mean small LDL particle concentrations measured by NMR were 770, 827 and 935 nmol/L for women (p<0.001) and 996, 1030 and 1040 nmol/L for men (p=0.037) among participants with normal, high normal and elevated ACR. Adjusting for age, race/ethnicity, diabetes, impaired fasting glucose, hypertension, smoking, medications, body mass index and serum creatinine, each two-fold greater ACR was associated with an increase in small LDL particle concentration of 27 nmol/L for women (p<0.001) and 14 nmol/L for men (p=0.008). Greater ACR was also associated with greater intermediate density lipoprotein particle concentration and smaller mean LDL particle size.

CONCLUSIONS

Mild elevations of urine ACR are associated with atherogenic lipoprotein abnormalities that are not directly observed with a standard lipid panel.

Cyclooxygenase polymorphisms and risk of cardiovascular events: the Atherosclerosis Risk in Communities (ARIC) study

Cyclooxygenase-derived prostaglandins modulate cardiovascular disease risk. We genotyped 2212 Atherosclerosis Risk in Communities study participants (1,023 incident coronary heart disease (CHD) cases; 270 incident ischemic stroke cases; 919 non-cases) with available DNA for polymorphisms in PTGS1 and PTGS2. Using a case-cohort design, associations between genotype and CHD or stroke risk were evaluated using proportional hazards regression. In Caucasians, the reduced function PTGS1 -1006A variant allele was significantly more common among stroke cases compared to non-cases (18.2 versus 10.6%, P=0.027). In African Americans, the reduced function PTGS2 -765C variant allele was significantly more common in stroke cases (61.4 versus 49.4%, P=0.032). No significant relationships with CHD risk were observed. However, aspirin utilization appeared to modify the relationship between the PTGS2 G-765C polymorphism and CHD risk (interaction P=0.072). These findings suggest that genetic variation in PTGS1 and PTGS2 may be important risk factors for the development of cardiovascular disease events. Confirmation in independent populations is necessary.

Adipokine levels and cardiovascular risk in patients with adrenal incidentaloma

Adrenal incidentalomas (AIs) have been associated with an increased incidence of several cardiovascular risk factors, similar to overt Cushing syndrome. Data about the involvement of the adipokines in the development of insulin resistance and atherosclerosis in AI are completely lacking. The aim of the present study was to evaluate plasma interleukin 6 (IL-6), adiponectin, resistin, tumor necrosis factor alpha (TNF-alpha), and monocyte chemoattractant protein 1 (MCP-1) levels in patients with AI. Plasma IL-6, adiponectin, resistin, TNF-alpha, and MCP-1 levels were measured in 20 healthy subjects (6 males; 14 females; age, 58.5 +/- 2.2 years; body mass index, 28.1 +/- 0.9 kg/m(2)) and in 20 patients (5 males; 15 females; age, 57.9 +/- 2.0 years; body mass index, 28.0 +/- 0.8 kg/m(2)) with AI and typical computed tomographic features of cortical adenoma, who were not affected by diabetes mellitus, hypertension, or other relevant diseases. All patients underwent anthropometric measurements and determination of basal corticotropin, cortisol, and urinary free cortisol excretion. Overnight dexamethasone test and 250-microg corticotropin test were performed in all cases. A subclinical Cushing syndrome was found in 3 patients, whereas the others had apparently nonfunctioning masses. Plasma IL-6, adiponectin, resistin, TNF-alpha, and MCP-1 levels were higher in patients than in controls (64.4 +/- 2.8 vs 5.5 +/- 0.6 pg/mL, 13.7 +/- 1.3 vs 3.6 +/- 0.5 microg/mL, 12.5 +/- 1.9 vs 5.1 +/- 0.2 ng/mL, 27.0 +/- 1.5 vs 22.2 +/- 1.5 pg/mL, 172.5 +/- 20.0 vs 104.4 +/- 19.5 pg/mL, respectively; P < .05) and apparently not affected by the presence of visceral obesity. Plasma IL-6 levels were negatively correlated with urinary free cortisol (r = -0.461, P < .05), and TNF-alpha levels were positively correlated with cortisol after the administration of 1 mg dexamethasone (r = 0.636, P < .01). In conclusion, patients with AI may show increased levels of adipokines (apparently not related to the presence of diabetes, hypertension, or obesity), which may be affected by the presence of the adrenal adenoma. For some adipokines, a direct production from the adrenal gland may be hypothesized even if other studies are needed to better investigate the role of adipokines in states of altered cortisol secretion.

[Microalbuminuria is a strong determinant for ischemic heart disease--also among non-diabetics]

Population studies have indicated that a urinary albumin excretion above 5 microg/min confers increased relative risk of coronary heart disease similar to the relative risk associated with the metabolic syndrome. This is perhaps because microalbuminuria reflects the presence of subclinical atherosclerosis. In a series of pathophysiological studies microalbuminuria was not associated with systemic transvascular sieving of lipoproteins. Measurement of urinary albumin excretion may be useful for risk stratification in primary health care for prevention of coronary heart disease. Intervention trials should be conducted.

Relationship of aortic atherosclerosis to acute renal failure following cardiac surgery

BACKGROUND

The presence of aortic atherosclerosis has been identified as a major risk factor for stroke after coronary artery bypass grafting (CABG). Whether aortic atherosclerosis is similarly related to the risk of acute renal failure (ARF), a common and important complication of CABG, is unknown.

METHODS

Rates of postoperative ARF were analyzed using data from 1,117 randomized patients in a multicenter controlled trial comparing standard CABG with CABG plus an experimental aortic catheter. Aortic atherosclerosis was prospectively measured using transesophageal echocardiography. The association of aortic atherosclerosis with postoperative renal failure was analyzed using multivariable logistic regression to adjust for confounding by baseline and intraoperative conditions.

RESULTS

Baseline creatinine clearance <40 ml/min and systolic hypertension were strong predictors of postoperative acute renal failure. Neither mild nor moderate aortic atherosclerosis was associated with the development of acute renal failure. Patients with moderate aortic atherosclerosis had a lower risk of acute renal failure (odds ratio = 0.53, p = 0.20) than those with lesser degrees of atherosclerosis.

CONCLUSIONS

Our results demonstrate that the presence of significant aortic atherosclerosis does not increase the risk of acute renal failure following CABG, and they suggest that cholesterol embolization from the aorta to the renal circulation is an infrequent cause of acute renal failure after bypass surgery. Strategies to decrease cholesterol embolization from the aorta are unlikely to significantly lower the rate of renal failure following bypass surgery.

Effect of plasma homocysteine level and urinary monomethylarsonic acid on the risk of arsenic-associated carotid atherosclerosis

Arsenic-contaminated well water has been shown to increase the risk of atherosclerosis. Because of involving S-adenosylmethionine, homocysteine may modify the risk by interfering with the biomethylation of ingested arsenic. In this study, we assessed the effect of plasma homocysteine level and urinary monomethylarsonic acid (MMA(V)) on the risk of atherosclerosis associated with arsenic. In total, 163 patients with carotid atherosclerosis and 163 controls were studied. Lifetime cumulative arsenic exposure from well water for study subjects was measured as index of arsenic exposure. Homocysteine level was determined by high-performance liquid chromatography (HPLC). Proportion of MMA(V) (MMA%) was calculated by dividing with total arsenic species in urine, including arsenite, arsenate, MMA(V), and dimethylarsinic acid (DMA(V)). Results of multiple linear regression analysis show a positive correlation of plasma homocysteine levels to the cumulative arsenic exposure after controlling for atherosclerosis status and nutritional factors (P < 0.05). This correlation, however, did not change substantially the effect of arsenic exposure on the risk of atherosclerosis as analyzed in a subsequent logistic regression model. Logistic regression analyses also show that elevated plasma homocysteine levels did not confer an independent risk for developing atherosclerosis in the study population. However, the risk of having atherosclerosis was increased to 5.4-fold (95% CI, 2.0-15.0) for the study subjects with high MMA% (> or =16.5%) and high homocysteine levels (> or =12.7 micromol/l) as compared to those with low MMA% (<9.9%) and low homocysteine levels (<12.7 micromol/l). Elevated homocysteinemia may exacerbate the formation of atherosclerosis related to arsenic exposure in individuals with high levels of MMA% in urine.

Increased urinary albumin excretion rates can be a marker of coexisting coronary artery disease in patients with peripheral arterial disease

Coexisting coronary artery disease (CAD) is an important cause of morbidity and mortality in patients with peripheral arterial disease (PAD). Clinical evaluation and noninvasive tests have some important limitations for the detection of CAD in patients with PAD. The purpose of this study was to investigate whether urinary albumin excretion (UAE) was a sign of atherosclerotic involvement of coronary arteries in patients with PAD. Our study consisted of 65 consecutive patients (56 men, 9 women, mean age; 59.7+/-7.9 years) with PAD who underwent coronary angiography. Urinary albumin excretion was measured in 24-hour urine samples by immunoprecipitation technique. PAD was defined as the presence of > or =50% stenotic lesions in at least 1 of the iliac, femoral, popliteal, tibialis anterior, tibialis posterior, or peroneal arteries. CAD was defined as > or =25% diameter stenosis in at least 1 coronary artery. Patients without any coronary lesions were accepted as having normal coronaries. Age, sex, distributions of coronary risk factors, and UAE rates were compared between patients with and without CAD. Mean UAE was 17.9+/-15.6 mg/day in the total population. Thirty-seven percent of patients had CAD, and 63% had no coronary lesion. UAE rates were 22.33+/-18.74 and 15.32+/-13.01 mg/day in patients with CAD and those with normal coronary arteries, respectively (p = 0.021). Microalbuminuria was detected in 25% in patients with CAD and 12% in those without coronary artery lesions (p = 0.184). The difference was not statistically significant. The distributions of other risk factors and sex were not different between the 2 groups. These data suggest that in patients with PAD, urinary albumin excretion rates may be used to determine those with a high probability of CAD. Further studies are required to decide whether this noninvasive testing is appropriate in detecting high-risk patients.

[Atherosclerosis risk factors among patients with diabetes mellitus type 2 diagnosed during hospitalisation due to other diseases in the year 2004]

In the year 2004 there were 2515 patients hospitalysed in the Internal Diseases Department in Dabrowa Tarnowska. In this group 670 of persons suffered from diabetes mellitus t 2. In more than 62 patients the diabetes was detected coincidentally during hospitalization on account of other diseases. Analysed was the occurrence of other risk factors of artherosclerosis in this group, such as: age, sex, hypertension (mild in 17.7%, moderate in 29.1% and severe in 33.9% of patients), obesity (45%), high serum level of cholesterol (200-250 mg% in 45 % and >250 mg% in 24% of patients), BMI indicator (>30 in 40% of subjects), serum level of creatinine (>1.2 mg% in 35.5%), presence of microalbuminuria (30-300 mg/24h in 29%) and proteinuria (17.7%).

Trace element status in Saudi patients with established atherosclerosis

BACKGROUND

Traditional coronary risk factors do not fully explain variations in the incidence of cardiovascular disease (CVD). Epidemiological studies have implicated perturbations in selenium, copper, and zinc metabolism in the aetiology of CVD. However, these studies have been principally undertaken in Caucasian populations, in whom trace element intake is generally sufficient.

METHOD

We have measured serum and urine selenium, copper, and zinc; and superoxide dismutase, glutathione peroxidase, and lipid peroxide concentrations in 130 Saudi male subjects with established CVD, and 130 age-matched controls.

RESULTS

Diabetes mellitus, positive smoking habit (p<0.0001 for both), and hypertension (p<0.05) were more prevalent among CVD patients. Urinary copper (p<0.0001) and zinc (p<0.05) were higher among controls. Serum selenium concentrations were lower among CVD patients (p<0.001), and a high proportion (52%) had selenium levels below 79mug/L compared to controls (22%) (p<0.0001). Conditional logistic regression analysis, showed the characteristics differentiating CVD patients from controls were serum zinc (odds ratio (OR) 0.92, confidence interval (CI) 0.85-0.99, p<0.05), serum copper/zinc ratio (OR 0.31, CI 0.10-0.96), serum selenium (OR 0.07, CI 0.02-0.31, p<0.0001), and urine selenium (OR 3.34, CI 1.40-7.99, p<0.01).

CONCLUSION

Measures of trace metals status appear to be associated with the risk of atherosclerosis in a Saudi male population.

Serum interleukin-18 levels are associated with nephropathy and atherosclerosis in Japanese patients with type 2 diabetes

OBJECTIVE

Interleukin (IL)-18 is a proinflammatory cytokine secreted from mononuclear cells. Serum concentration of IL-18 is a strong predictor of death in patients with cardiovascular diseases. Recent studies have shown that microinflammation is involved in the pathogenesis of diabetic nephropathy as well as of cardiovascular diseases. This study aimed to test the hypothesis that the serum level of IL-18 is a common predictor of nephropathy and atherosclerosis in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Eighty-two Japanese patients with type 2 diabetes and 55 age- and sex-matched healthy control subjects were enrolled. Patients with renal dysfunction (creatinine clearance <1 ml/s) were excluded. We assessed clinical parameters and measured serum and urinary IL-18 levels, serum IL-6 levels, carotid intima-media thickness (IMT), and brachial-ankle pulse wave velocity (baPWV) in all patients. Further, we evaluated changes of urinary albumin excretion rate (AER) after 6 months in 76 diabetic patients.

RESULTS

Serum and urinary IL-18 levels were significantly elevated in patients with type 2 diabetes as compared with control subjects (serum IL-18 179 +/- 62 vs. 121 +/- 55 pg/ml, P < 0.001; urinary IL-18 97 +/- 159 vs. 47 +/- 54 pg/ml, P = 0.035). Univariate linear regression analysis showed significant positive correlations between serum IL-18 and AER (r [correlation coefficient] = 0.525, P < 0.001), HbA(1c) (r = 0.242, P = 0.029), high-sensitivity C-reactive protein (hs-CRP) (r = 0.240, P = 0.031), and urinary beta-2 microglobulin (r = 0.235, P = 0.036). Serum IL-18 levels also correlated positively with carotid IMT (r = 0.225, P = 0.042) and baPWV (r = 0.232, P = 0.040). We also found a significant correlation between urinary IL-18 and AER (r = 0.309, P = 0.005). Multivariate linear regression analysis showed that AER (standard correlation coefficients [B] = 0.405, P < 0.001) and hs-CRP (B = 0.207, P = 0.033) were independently associated with serum IL-18 levels. AER was also independently associated with urinary IL-18 levels (B = 0.295, P = 0.005). Moreover, serum and urinary IL-18 levels correlated positively with AER after 6 months (r = 0.489, P < 0.001 and r = 0.320, P = 0.005) and changes in AER during the follow-up period (r = 0.268, P = 0.018 and r = 0.234, P = 0.042).

CONCLUSIONS

Serum levels of IL-18 might be a predictor of progression of diabetic nephropathy as well as cardiovascular diseases.