The clinical significance of betaine,an osmolyte with a key role in methyl group metabolism

Betaine is an essential osmolyte and source of methyl groups and comes from either the diet or by the oxidation of choline. Its metabolism methylates homocysteine to methionine, also producing N,N-dimethylglycine. Betaine insufficiency is associated with the metabolic syndrome, lipid disorders and diabetes, and may have a role in vascular and other diseases. Betaine is important in development, from the pre-implantation embryo to infancy. Betaine supplementation improves animal and poultry health, but the effect of long-term supplementation on humans is not known, though reports that it improves athletic performance will stimulate further studies. Subsets of the population that may benefit from betaine supplementation could be identified by the laboratory, in particular those who excessively lose betaine through the urine.Plasma betaine is highly individual, in women typically 20–60 μmol/L and in men 25–75 μmol/L. Plasma dimethylglycine is typically < 10 μmol/L. Urine betaine excretion is minimal, even following a large betaine dose. It is constant, highly individual and normally < 35 mmol/mole creatinine. The preferred method of betaine measurement is by LC-MS/MS, which is rapid and capable of automation. Slower HPLC methods give comparable results. Proton NMR spectrometry is another option but caution is needed to avoid confusion with trimethylamine-N-oxide.     

Effects of anticoagulants on human plasma soluble corin levels measured by ELISA

BackgroundRecently, soluble corin was detected in human plasma. In patients with heart failure, plasma corin levels were lower than that of normal controls. In this study, we analyzed experimental conditions for measuring plasma or serum corin by an immunoassay.MethodsSerum and plasma corin levels were measured by ELISA. Effects of different anticoagulants (EDTA, heparin and sodium citrate) on plasma corin levels were examined.ResultsCorin levels in serum were similar to that in plasma with heparin (950 ± 305 vs. 929 ± 301 pg/ml, n = 40, p = 0.73), but were significantly higher than those in plasma with sodium citrate (735 ± 237 pg/ml, p < 0.01) or EDTA (716 ± 261 pg/ml, p < 0.001). Native and recombinant human corin proteins were stable in human plasma with EDTA at 4 °C or underwent freezing-and-thawing. In 348 healthy Chinese individuals, plasma corin levels ranged from 216 to 1663 pg/ml. The levels were higher in males than that in females (842 ± 283 vs. 569 ± 192 pg/ml, p < 0.001).ConclusionSoluble corin was stable in plasma samples. Plasma soluble corin levels vary depending on anticoagulants used. Samples containing heparin had significantly higher levels of corin than that in samples with EDTA or sodium citrate.     

Stability of plasma adrenocorticotrophic hormone (ACTH): Influence of hemolysis,rapid chilling,time, and the addition of a maleimide

ObjectivesThe aim of this study was to examine the effects of hemolysis, rapid chilling, time, and the addition of a maleimide on the stability of human plasma ACTH measurements.Design and methodsPartially hemolyzed EDTA blood (n = 10), initially at 37 °C, was centrifuged at 4 °C either immediately or after rapid chilling in ice/water. Plasma ACTH was then measured either immediately, or after 1 h at 22 °C with or without the addition of 2 mM N-phenyl maleimide (NPM).ResultsFor 0.2% hemolysis compared to no hemolysis, the mean (±SEM) loss with immediate centrifugation and immediate ACTH measurement was 11 ± 1%. This loss was significantly (p < 0.002) reduced to 6 ± 1% by an initial rapid chilling of the samples. For analysis after 1 h at 22 °C, the addition of NPM decreased the loss of ACTH from 15 ± 2% to 2 ± 2% (p < 0.002).ConclusionRapid chilling, prompt analysis, and addition of NPM can each reduce the interference of hemolysis in the measurement of plasma ACTH concentrations.     

Correlation between concentrations of 8-oxo-7,8-dihydro-2′-deoxyguanosine in urine,plasma and saliva measured by on-line solid-phase extraction LC-MS/MS

Background8-Oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo) is the most frequently measured biomarker of oxidative stress. Chromatographic-based methods for 8-oxodGuo in urine are well established; however, the 8-oxodGuo measurement in plasma and saliva has been problematic.MethodsWe firstly and successfully applied an on-line solid-phase extraction (SPE) LC-MS/MS following manual SPE pretreatment to quantify the 8-oxodGuo both in plasma and saliva. Urine, plasma and saliva specimens were simultaneously collected from 50 healthy adults and measured for 8-oxodGuo.ResultsMean baseline levels of 8-oxodGuo in plasma and saliva were 21.7 ± 9.2 and 5.1 ± 2.6 pg/ml, respectively, being far lower than that in urine (6.2 ± 4.8 ng/ml). The 8-oxodGuo levels obtained in this study for plasma and saliva were, however, up to several hundred times lower than those reported by commercial ELISA kit in the literature. Furthermore, the 8-oxodGuo levels in plasma and saliva were significantly correlated with the 8-oxodGuo levels in urine (Spearman correlation coefficients, r = 0.33, P = 0.02 for plasma and r = 0.56, P = 0.0015 for saliva). 8-OxodGuo in plasma was also correlated with the 8-oxodGuo in saliva (r = 0.52, P = 0.0041).ConclusionsSignificantly correlations were observed between plasma, saliva and urine, giving the possibility of using other body fluids in addition to urine for assessing whole body oxidative stress.     

Relation between riboflavin,flavin mononucleotide and flavin adenine dinucleotide concentrations in plasma and red cells in patients with critical illness

BackgroundThere is some evidence that the relationship between plasma and red cell vitamin B2 concentrations is perturbed in the critically ill patient. The aim of the present study was to examine the longitudinal interrelationships between riboflavin, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) in plasma and red cells in patients with critical illness.MethodsRiboflavin, FMN and FAD concentrations were measured, by HPLC, in plasma and red cells in healthy subjects (n = 119) and in critically ill patients (n = 125) on admission and on follow-up.ResultsOn admission, compared with the controls, critically ill patients had significantly higher plasma riboflavin and FMN concentrations (p < 0.001) and lower median plasma FAD concentrations (p < 0.001). In the red cell, FAD concentrations were significantly lower in critically ill patients (p < 0.001). In healthy subjects, plasma riboflavin was directly associated with both plasma FMN (r_s = 0.55, p < 0.001) and plasma FAD (r_s = 0.49, p < 0.001). Red cell riboflavin was directly associated with red cell FMN (r_s = 0.52, p < 0.001) but not red cell FAD. In the critically ill patients, plasma riboflavin was not significantly associated with either plasma FMN or FAD. Red cell riboflavin was directly associated with red cell FMN (r_s = 0.79, p < 0.001) and red cell FAD (r_s = 0.72, p < 0.001). Longitudinal measurements (n = 60) were similar.ConclusionsThe relationship between plasma riboflavin, FMN and FAD was significantly perturbed in critical illness. This effect was less pronounced in red cells. Therefore, red cell FAD concentrations are more likely to be a reliable measure of status in the critically ill patient.     

Reverse modulation of the HDL Anionic Peptide Factor and phospholipid transfer protein activity in coronary artery disease and type 2 diabetes mellitus

ObjectivesThe high density lipoprotein Anionic Peptide Factor (HDL₃-APF) was previously described as an apolipoprotein that promotes the reverse cholesterol transport. Since phospholipid transfer protein (PLTP) is involved in such mechanism we attempted to focus on the two APF and PLTP proteins.Design and methodsWe recruited 56 type 2 diabetic patients with (n = 36) or without (n = 20) coronary artery disease (CAD) and 19 CAD patients. The three groups were compared to 39 healthy control subjects. In all groups, lipid profile was determined and plasma APF concentrations and PLTP activity were measured.ResultsIn all patients, the PLTP activity was significantly increased in comparison with controls (p < 0.01), in concomitance with a plasma APF level decrease in groups with CAD (with and without type 2 diabetes) (p < 0.01). Multiple linear regression analysis demonstrated that, when apoA-I, HDL-C, HDL-phospholipids and PLTP activity were taken into account as independent variables (after univariate regression analysis), HDL-PL was positively and independently related to APF (p < 0.0001 in whole population; p = 0.0090 in controls) and PLTP activity was negatively and independently related to APF in whole population and all patients' groups (all p < 0.05), but positively and independently associated to APF in controls (p = 0.0005).ConclusionsAPF could be considered as a specific marker against CAD and type 2 diabetes mellitus and our results confirm the atherogenic behavior of PLTP in CAD. Thus, these two proteins are likely to be regulated in a reverse manner.     

Plasma osteopontin concentration correlates with the severity of hepatic fibrosis and inflammation in HCV-infected subjects

BackgroundThe association between OPN level and the histological severity of hepatic fibrosis and inflammation in hepatitis C virus (HCV) induced liver fibrosis remains unknown.Methods120 chronic HCV-infected subjects and 75 controls were enrolled in this study. Assessment of liver histology was performed based on liver biopsy. Plasma OPN levels were determined.ResultsSignificant differences were noted in the mean plasma OPN levels between subjects with extensive fibrosis and those with mild fibrosis (4.29 ± 1.01 ng/ml vs. 2.15 ± 0.63 ng/ml, respectively; p < 0.001). Similarly, the subjects with higher histological activity index (HAI) score had elevated OPN levels than those with mild HAI score (4.41 ± 1.11 ng/ml vs. 2.25 ± 0.94 ng/ml, respectively; p < 0.001). The correlation between the plasma OPN levels and the severity of liver fibrosis degree and HAI score were noted (r = 0.945, and r = 0.788, respectively both p < 0.001). Logistic regression analysis showed that serum OPN was an independent risk factor contributing to extensive liver fibrosis and inflammation (p = 0.0018 and p < 0.001, respectively) in patients with HCV subjects.ConclusionThe plasma OPN level is correlated with the severity of liver fibrosis and inflammation, suggesting OPN could be used as a biomarker to evaluate the severity of liver damages in HCV subjects.     

Association of cell-free plasma DNA with perioperative mortality in patients with suspected acute mesenteric ischemia

BackgroundDiagnosing patients with acute mesenteric ischemia (AMI) in the emergency ward is challenging. This study assesses the usefulness of plasma DNA in patients with clinically suspected AMI.Methods130 consecutive patients who underwent laparotomy were studied. Cell-free plasma DNA was measured by real-time quantitative PCR assay for the β-globin gene. The primary endpoint was the accuracy of plasma DNA for predicting 30-day mortality.ResultsSurgery revealed AMI in 99 patients and alternative diagnoses in 31 patients. Forty-six patients with AMI died (46.6%) as compared to 6 (19.4%) in the non-AMI group (p < 0.05). The DNA concentration at admission was significantly higher in patients with AMI (median 7340 GE/ml, versus, 2735 GE/ml, p < 0.01) and in AMI patients who died (8830 GE/ml, versus 4970 GE/ml, p < 0.05). The area under the ROC curves for plasma DNA as a marker for mesenteric ischemia and independent predictor for 30-day mortality were 0.708 (95% CI 0.701–0.890) and 0.815 (95% CI 0.735–0.894). Multiple logistic regression analysis showed that the risk of hospital mortality increased 1.52-fold for every 1000 GE/ml increase in plasma DNA.ConclusionsPlasma DNA levels may be a useful biomarker in predicting the outcome of patients with AMI.     

High density lipoprotein-anionic peptide factor effect on reverse cholesterol transport in type 2 diabetic patients with and without coronary artery disease

ObjectivesTo verify if HDL3 Anionic Peptide Factor (HDL3-APF) is as an apolipoprotein that promotes the reverse cholesterol transport.Design and methodsWe investigated a possible association between plasma HDL3-APF concentration, cholesterol efflux from Fu5AH cells and cholesteryl ester transfer protein (CETP) activity in type 2 diabetic patients with coronary artery disease (CAD) (n = 36), those without CAD (n = 20), and 37 healthy subjects.ResultsPlasma APF concentrations were decreased in diabetics with CAD compared to controls (p < 0.01). Cellular cholesterol efflux was decreased in diabetics without and with CAD, (p < 0.01 and p < 0.001 respectively). CETP activity was significantly elevated in all patient groups. Multiple linear regression analysis shows that cholesterol efflux was independently and positively related only to APF concentrations in controls.ConclusionsAPF is likely to be a key independent factor for promoting cellular cholesterol efflux in healthy subjects. However this association is altered in type 2 diabetes.     

Plasma concentrations of Gas6 and soluble Axl correlate with disease and predict mortality in patients with critical limb ischemia

IntroductionCritical limb ischemia (CLI) is a severe peripheral arterial disease, characterized by rest pain, ulcers and gangrene in the legs. Gas6 is a vitamin K-dependent protein, which binds and activates the tyrosine kinase receptor Axl. Gas6-mediated Axl-signaling influences endothelial activation, neointima formation and immune regulation. Axl can be cleaved and soluble Axl (sAxl) is detectable in circulation.Design and methodsWe quantified plasma concentrations of Gas6 and sAxl in 189 CLI patients and 204 controls.ResultsGas6 and sAxl concentrations were increased in the CLI patients (p < 0.0001) and correlated to C-reactive protein, interleukin-6, tumor necrosis factor α and neopterin. Patients who died within 3 years of sampling (n = 84) had increased concentrations of Gas6 and sAxl as compared to survivors (p = 0.0009 and p = 0.0011).ConclusionsPlasma concentrations of Gas6 and sAxl correlate to inflammation and predict survival. This indicates that Gas6 and sAxl have a role in CLI, presumably connected to the inflammatory process.     

Gender-specific effect of Pro12Ala polymorphism in peroxisome proliferator-activated receptor γ-2 gene on obesity risk and leptin levels in a Tunisian population

ObjectivesThis study was undertaken to investigate the impact of the Pro12Ala (rs1801282) polymorphism of the peroxisome proliferator-activated receptor γ-2 (PPARγ-2) gene on obesity or body mass index (BMI) and plasma leptin, insulin, adiponectin and lipid levels in a sample of the Tunisian population.Design and MethodsThe study included 387 obese patients and 288 control subjects. The Pro12Ala genotype was determined by polymerase chain reaction followed by a digestion with the restriction of endonuclease BstUI.ResultsIn the whole population, there is no significant difference in genotype frequencies of the Pro12Ala polymorphism between obese patients and controls. However, separate analysis by gender revealed that obese men (but not women) had significantly higher frequency of Pro/Ala genotypes compared to controls (12.2% vs. 4.1%; χ² = 6.76, p = 0.009). In comparison to Pro/Pro homozygotes, Ala-allele bearers had a significantly higher risk of obesity [OR (95% CI) = 3.26 (1.28–8.33)]. When obese subjects were stratified according to type 2 diabetes status, the association with obesity was only significant in obese non-diabetic patients [OR (95% CI) = 3.74 (1.43–9.74), p =  0.007]. Additionally, obese male patients carrying the Ala-allele had significantly higher body mass index (p =  0.007) and plasma leptin levels (p =  0.023) compared to those homozygous for Pro-allele. The significant effect of Pro12Ala polymorphism on plasma leptin levels disappeared after adjustment for age and BMI.ConclusionThe present study provides evidence that the Pro12Ala polymorphism of the PPARγ-2 gene is associated with obesity in non-diabetic men from Tunisian origin.     

Correlation of endothelin 1 plasma levels with plasma antioxidant capacity in elderly patients treated for hypertension

Experimental studies confirmed that reactive oxygen species increase endothelin-1 (ET-1) synthesis, and modulate ET-1 signaling pathway resulting in vasoconstriction and vascular remodeling.The aim of this study was to evaluate the relationship between plasma ET-1 concentration and antioxidant status in patients with essential hypertension and type 2 diabetes mellitus.Methods78 hypertensive patients, 53.8% diabetic, mean age 72.1 ± 7.07 were examined. The plasma concentration of glucose, creatinine, uric acid, bilirubin, cholesterol, insulin, HbA1c and ET-1 were measured. Antioxidant status was assessed by Ferric Reducing Ability of Plasma (FRAP), vitamin C concentration and erythrocyte superoxide dismutase (SOD) activity.ResultsWith diabetes ET-1 concentration was higher (1.35 ± 0.51 vs 1.12 ± 0.46 pg/mL, p = 0.04). The negative correlations between ET-1 concentration and FRAP (r = ? 0.50, p < 0.0001), vitamin C (r = ? 0.296, p = 0.01) and SOD (r = ? 0.44, p = 0.001) were found. Concentration of ET-1 correlated positively with SBP (r = 0.33, p = 0.005) but not with DBP. The relationship between DBP and ET-1 only in subjects with DBP > 110 mm Hg and FRAP < 0.40 mmol/L was found. In multiple regression analysis plasma ET-1 levels were associated independently with FRAP (beta = ? 0.583, p = 0.003) and plasma vitamin C (beta = ? 0.407, p = 0.04).ConclusionsIn hypertensive and diabetic patients higher plasma endothelin-1 level was independently associated with lower plasma antioxidant status measured by FRAP and decreased vitamin C concentration, which may be a result of increased oxidative stress in these diseases.     

Mutation -538 T/C in bone morphogenetic protein 4 do not increase the risk in sickle-cell disease with orthopedic complications but strongly associated with increased LDH and uric acid level in Indian patients from Chhattisgarh and Jharkhand states

BackgroundBone morphogenetic protein (BMP) are involved in the various orthopedic complications such as avascular necrosis, osteonecrosis and bone turnover, therefore genes coding for proteins, like BMP4, can be potential candidate for studying orthopedic disorders.MethodsA case–control study was conducted to examine the association between SNP T538C of BMP4 and orthopedic complications in sickling patients by employing PCR-RFLP.ResultsA total of 200 cases and 172 control groups were studied from Indian population. T538C SNP has not been implicated in disease and doesn't increase the risk (OR = 0.89, OR = 0.68). We observed no significant association between the T538C polymorphism and case group in the studied population. However, we observed significantly increased uric acid and LDH level in homowild (TT), heteromutant (TC) and homomutant (CC) in case group compared to control group ( all p = 0.0001) and (p = 0.0001, p = 0.0001, p = 0.015 and p = 0.0001, p = 0.0001, p = 0.0001 respectively) in the studied population.ConclusionsThe T/C polymorphism in BMP4 is not associated with case group and in view of present observation, we suggest that evaluation of LDH and uric acid level and its association with polymorphisms in the BMP4 may be considered to be reliable molecular and biochemical markers, and possess promising rational for diagnostic potential in clinical cases.     

Plasma and synovial fluid sclerostin are inversely associated with radiographic severity of knee osteoarthritis

ObjectiveThe purpose of this study was to analyze sclerostin in plasma and synovial fluid of knee osteoarthritis (OA) patients and to investigate the association between sclerostin levels and radiographic severity.Design and methodsA total of 190 subjects (95 knee OA patients and 95 healthy controls) were recruited in the present study. Sclerostin levels in plasma and synovial fluid were assessed using an enzyme-linked immunosorbent assay. OA grading was performed using the Kellgren–Lawrence classification.ResultsPlasma sclerostin levels were significantly lower in OA patients than in healthy controls (P = 0.004). Additionally, sclerostin levels in plasma were significantly higher with respect to paired synovial fluid (P < 0.001). Moreover, sclerostin levels in plasma and synovial fluid demonstrated a significant inverse correlation with the radiographic severity of knee OA (r = − 0.464, P < 0.001 and r = − 0.592, P < 0.001, respectively). Subsequent analysis revealed that there was a positive correlation between plasma and synovial sclerostin levels (r = 0.657, P < 0.001).ConclusionsSclerostin was significantly lower in OA plasma samples when compared with healthy controls. Plasma and synovial fluid sclerostin levels were inversely associated with the radiographic severity of knee OA. Therefore, sclerostin may be utilized as a biochemical marker for reflecting disease severity in primary knee OA.     

Increased large VLDL and small LDL particles are related to lower bilirubin in Type 2 diabetes mellitus

ObjectivesBilirubin may protect against atherosclerotic cardiovascular disease by virtue of its anti-oxidative properties, but lower bilirubin may also be associated to atherogenic lipoprotein abnormalities. We determined associations of plasma (apo)lipoproteins and lipoprotein subfractions in subjects with and without type 2 diabetes mellitus (T2DM).Design and methodsPlasma (apo)lipoproteins, lipoprotein subfractions (nuclear magnetic resonance spectroscopy) and serum total bilirubin levels were determined in 53 T2DM patients and in 53 non-diabetic subjects.ResultsTriglycerides, large VLDL, small LDL and small HDL particles were increased (all p < 0.05), whereas HDL cholesterol, apoA-I and large HDL particles were decreased (all p < 0.05), coinciding lower bilirubin levels in T2DM (p < 0.001). In age- and sex-adjusted analysis, total cholesterol, non-HDL cholesterol, triglycerides, apoB, apoE, large VLDL and small LDL were negatively correlated with bilirubin, but HDL cholesterol was positively correlated with bilirubin in T2DM (p < 0.05 to p < 0.001). Multivariable linear regression analyses demonstrated that in all subjects combined total cholesterol, non-HDL cholesterol, triglycerides and apoE were negatively associated with bilirubin after adjustment for age, sex, T2DM, body mass index and alanine aminotransferase (all p < 0.05). Further multivariable linear regression analysis showed that large VLDL and small LDL particles were negatively associated with bilirubin, whereas large HDL particles were associated positively with bilirubin (p < 0.05).ConclusionsIncreased triglycerides, as well as large VLDL and small LDL particles are associated negatively, whereas HDL cholesterol is associated positively with bilirubin in T2DM. The proposed pro-atherogenic effects of low bilirubin could in part be attributed to relationships with abnormalities in (apo)lipoproteins and lipoprotein subfraction characteristics.     

High-level expression of early growth response-1 and association of polymorphism with total IgE and atopy in allergic rhinitis adults

BackgroundEarly growth response-1 (Egr-1) is expressed in human airways and its polymorphisms have been associated with total IgE and atopy in asthmatic patients. We investigated the effects of Chinese-tagging single nucleotide polymorphism (SNP) of Egr-1 and its mRNA expression on allergic rhinitis (AR) traits.MethodsAmong 214 Chinese AR adults and 259 controls, tag SNP ?4071 A → G was genotyped and mRNA expression in peripheral blood was quantified by real-time PCR.ResultsEgr-1 mRNA expression was significantly higher in patients than controls (median of 0.23 vs 0.15 fold GAPDH expression; p < 0.001). Its expression was not associated with ? 4071 polymorphism. However, significant correlations were found between ? 4071 A → G with increased plasma total IgE (p = 0.028) and atopy (p = 0.030) in patients. Logistic regression confirmed the association (p = 0.034) with age and gender adjusted. Patients homozygous for the A allele had a 2.3-fold and 1.9-fold risks, respectively of having increased plasma total IgE and atopy than those G allele carriers.ConclusionsWe showed high levels of Egr-1 mRNA expression and demonstrated a significant association of polymorphism with increased plasma total IgE and atopy in AR patients. It may be useful to explore the pharmacogenetics of Egr-1 inhibitors.     

Plasma proprotein convertase subtilisin–kexin type 9 is predominantly related to intermediate density lipoproteins

ObjectivesProprotein convertase subtilisin–kexin type 9 (PCSK9) is a key regulator of low density lipoprotein (LDL) receptor processing, but the PCSK9 pathway may also be implicated in the metabolism of triglyceride-rich lipoproteins. Here we determined the relationship of plasma PCSK9 with very low density lipoprotein (VLDL) and LDL subfractions.Design and methodsThe relationship of plasma PCSK9 (sandwich enzyme-linked immunosorbent assay) with 3 very low density lipoprotein (VLDL) and 3 low density lipoprotein (LDL) subfractions (nuclear magnetic resonance spectroscopy) was determined in 52 subjects (30 women).ResultsIn age- and sex-adjusted analysis plasma PCSK9 was correlated positively with total cholesterol, non-high density lipoprotein cholesterol and LDL cholesterol (r = 0.516 to 0.547, all p < 0.001), as well as with triglycerides (r = 0.286, p = 0.044). PCSK9 was correlated with the VLDL particle concentration (r = 0.336, p = 0.017) and with the LDL particle concentration (r = 0.362, p = 0.010), but only the relationship with the LDL particle concentration remained significant in multivariable linear regression analysis. In an analysis which included the 3 LDL subfractions, PCSK9 was independently related to intermediate density lipoproteins (IDL) (p < 0.001), but not to other LDL subfractions.ConclusionsThis study suggests that plasma PCSK9 predominantly relates to IDL, a triglyceride-rich LDL subfraction. The PCSK9 pathway may affect plasma triglycerides via effects on the metabolism of triglyceride-rich LDL particles.     

Soluble transferrin receptor in urine,a new biomarker for IgA nephropathy and Henoch–Schönlein purpura nephritis

ObjectivesIgA nephropathy (IgAN) and Henoch–Schönlein purpura nephritis (HSPN) might represent different ends of a continuous spectrum of glomerular disease. In both conditions, upregulated soluble transferrin receptor (sTfR) might be excreted in urine, which could be a potential biomarker to monitor disease activity and therapeutic response.MethodsIn this pilot study, 132 Caucasian patients consulting the Nephrology Department at the Ghent University Hospital because of a glomerulopathy and 50 normal controls were included. Urinary sTfR concentrations were determined in concentrated urine using a newly developed latex-enhanced immunonephelometric assay.ResultsMedian urinary sTfR concentration was higher in patients with a primary glomerulopathy than in healthy subjects (p < 0.0001). More importantly, absolute median levels of urinary sTfR were markedly higher in patients with active IgAN or HSPN [10 μg/L, 95% confidence interval (CI): 6–18 μg/L] in comparison with those with other morphological types of glomerulopathy (2 μg/L, 95%CI: 1–4 μg/L) (p < 0.0001). A statistically significant difference in urinary sTfR concentration was observed between patients with active IgAN or HSPN and patients who had achieved partial or complete remission (p < 0.0001). Multiple regression analysis with urinary sTfR as dependent variable revealed that proteinuria was the main predictor of urinary sTfR concentration (r² = 0.52, p < 0.001).ConclusionDetermination of sTfR in urine is a new and sensitive method for a potential biomarker of IgAN and HSPN.     

Impact of radiotherapy and chemotherapy on biomarkers of oxidative DNA damage in lung cancer patients

ObjectivesTo assess oxidative damage to DNA during lung cancer (LC) treatments.Design and methodsUrinary levels of 8-oxoguanine (8-oxoGua) and levels of 8-oxo-2′-deoxyguanosine (8-oxodG) from urine and whole blood were determined in 36 non-cancer controls and 65 LC patients before any treatments. Samples were also obtained of LC patients during and after radiotherapy (RT, n = 33) and chemotherapy (CT, n = 16).ResultsStage IV LC patients had higher urinary 8-oxoGua and 8-oxodG levels than patients with stage I–III disease (p = 0.044 and p = 0.034, respectively). Urinary 8-oxodG levels increased during the first week of RT (p < 0.001). Nuclear 8-oxodG increased during RT and 3 months after start of RT. Nuclear 8-oxodG levels also rose between the first two CT cycles (p = 0.043), and urinary 8-oxodG levels during the sixth CT cycle (p = 0.009).ConclusionsUrinary DNA damage biomarker levels may be associated with LC stage. Both RT and CT increase the parameters of DNA oxidation.     

Relationship of proprotein convertase subtilisin-kexin type 9 levels with resistin in lean and obese subjects

ObjectivesProprotein convertase subtilisin-kexin type 9 (PCSK9), a key regulator of low density lipoprotein receptor expression, has recently been reported to be upregulated by resistin in HepG2 cells and human primary hepatocytes. Whether this translates into a positive relationship of plasma PCSK9 with resistin levels in humans with varying degrees of obesity is unknown.Design and methodsWe assessed the extent to which plasma PCSK9 levels are determined by resistin in individuals with varying degrees of obesity.ResultsIn 80 subjects (35 women; no diabetes mellitus) with body mass index ranging from 19.4 to 40.4 kg/m², plasma PCSK9 levels were not positively related to resistin (r = ? 0.161, p = 0.154). Despite positive correlations of non-high density lipoprotein cholesterol (r = 0.378, p < 0.001), low density lipoprotein (r = 0.292, p < 0.01) and apolipoprotein B (apoB) (r = 0.266, p < 0.05) with PCSK9, none of these apolipoprotein (apo) B-containing lipoprotein measures was positively related to resistin (p > 0.10 for all). In subjects with BMI < 25.0 kg/m² (n = 38), PCSK9 was even inversely related to resistin (r = ? 0.322, p = 0.049), and this relationship remained present after controlling for either leptin (p = 0.027) or insulin resistance (P = 0.031). In subjects with BMI ≥ 25.0 kg/m² (n = 42), PCSK9 was unrelated to resistin (r = ? 0.064, p = 0.69).ConclusionsThis study demonstrates that there is no positive association of plasma PCSK9 with resistin in lean and moderately obese individuals. Our data question whether circulating resistin is a physiologically important determinant of higher PCSK9 levels.