Establishing effective interpretation criteria in hair analysis to distinguish between passive and active cocaine exposure: Insights from authentic hair samples collected from professional individuals exposed to cocaine.

Interpretation results of hair analysis, particularly for cocaine, can be challenging due to the need to differentiate between active use or passive contamination. Our study aimed to assess the impact of varying degrees of passive cocaine exposure hair analysis results and their interpretation. Hair samples (n = 25) were categorized based on the declared cocaine exposure of volunteers: (a) high, involving handling up to several kilograms of cocaine powder from dismantling illegal distribution sites; (b) medium, where staff dealt with cocaine blocks (up to kilograms); and (c) low, with staff in contact with up to grams of cocaine for laboratory analysis. Hair samples were decontaminated using dichloromethane, water, and methanol. The samples and final wash were analyzed for cocaine, benzoylecgonine, norcocaine, cocaethylene, m-OH-benzoylecgonine, and ecgonine methyl ester using a validated UPLC-MS/MS method. Cocaine hair concentrations ranges were as follows (pg/mg): high (n = 53 segments) < LLOQ(32)-7046; medium (n = 91) < LLOQ-939; and low (n = 54) < LLOQ-292. All hair samples had concentrations below the LLOQ for cocaethylene, ecgonine methyl ester, and m-OH-benzoylecgonine. Applying the SoHT cocaine cut-off in combination with a hair/wash ratio criterion identified 97% of the samples as contaminated. This study advocates for a comprehensive approach in evaluating cocaine hair concentrations. This involves integrating the 500 pg/mg decision limit for cocaine with a criterion comparing wash and hair concentration. Additionally, confirming the presence of specific metabolites is crucial. This multifaceted method effectively distinguishes between environmental contamination and active cocaine usage. The research contributes significantly to refining cocaine exposure assessment in professional contexts.

Comparison of Spectroscopic Techniques Combined with Chemometrics for Cocaine Powder Analysis.

Spectroscopic techniques combined with chemometrics are a promising tool for analysis of seized drug powders. In this study, the performance of three spectroscopic techniques [Mid-InfraRed (MIR), Raman and Near-InfraRed (NIR)] was compared. In total, 364 seized powders were analyzed and consisted of 276 cocaine powders (with concentrations ranging from 4 to 99 w%) and 88 powders without cocaine. A classification model (using Support Vector Machines [SVM] discriminant analysis) and a quantification model (using SVM regression) were constructed with each spectral dataset in order to discriminate cocaine powders from other powders and quantify cocaine in powders classified as cocaine positive. The performances of the models were compared with gas chromatography coupled with mass spectrometry (GC-MS) and gas chromatography with flame-ionization detection (GC-FID). Different evaluation criteria were used: number of false negatives (FNs), number of false positives (FPs), accuracy, root mean square error of cross-validation (RMSECV) and determination coefficients (R2). Ten colored powders were excluded from the classification data set due to fluorescence background observed in Raman spectra. For the classification, the best accuracy (99.7%) was obtained with MIR spectra. With Raman and NIR spectra, the accuracy was 99.5% and 98.9%, respectively. For the quantification, the best results were obtained with NIR spectra. The cocaine content was determined with a RMSECV of 3.79% and a R2 of 0.97. The performance of MIR and Raman to predict cocaine concentrations was lower than NIR, with RMSECV of 6.76% and 6.79%, respectively and both with a R2 of 0.90. The three spectroscopic techniques can be applied for both classification and quantification of cocaine, but some differences in performance were detected. The best classification was obtained with MIR spectra. For quantification, however, the RMSECV of MIR and Raman was twice as high in comparison with NIR. Spectroscopic techniques combined with chemometrics can reduce the workload for confirmation analysis (e.g., chromatography based) and therefore save time and resources.

Rapid classification and quantification of cocaine in seized powders with ATR-FTIR and chemometrics.

Traditionally, fast screening for the presence of cocaine in unknown powders is performed by means of colour tests. The major drawbacks of these tests are subjective colour evaluation depending on the operator ('50 shades of blue') and a lack of selectivity. An alternative fast screening technique is Fourier Transform InfraRed (FTIR) spectrometry. This technique provides spectra that are difficult to interpret without specialized expertise and shows a lack of sensitivity for the detection of cocaine in mixtures. To overcome these limitations, a portable FTIR spectrometer using Attenuated Total Reflectance (ATR) sampling was combined with a multivariate technique, called Support Vector Machines (SVM). Representative street drug powders (n = 482), seized during the period January 2013 to July 2015, and reference powders (n = 33) were used to build and validate a classification model (n = 515) and a quantification model (n = 378). Both models were compared with the conventional chromatographic techniques. The SVM classification model showed a high sensitivity, specificity, and efficiency (99%). The SVM quantification model determined cocaine content with a root mean squared error of prediction (RMSEP) of 6% calculated over a wide working range from 4 to 99 w%. In conclusion, the developed models resulted in a clear output (cocaine detected or cocaine not detected) and a reliable estimation of the cocaine content in a wide variety of mixtures. The ATR-FTIR technique combined with SVM is a straightforward, user-friendly, and fast approach for routine classification and quantification of cocaine in seized powders. Copyright © 2016 John Wiley & Sons, Ltd.

Novel method for simultaneous determination of p-cresylsulphate and p-cresylglucuronide: clinical data and pathophysiological implications.

BACKGROUND: The uraemic retention solutes p-cresylsulphate (pCS) and p-cresylglucuronide (pCG), two conjugates of p-cresol, were never determined simultaneously. In the present paper, a high-performance liquid chromatography (HPLC) method was developed and used to quantify both compounds in parallel in an in vivo observational study and their in vitro effect was evaluated by flow cytometry. METHODS: pCS and pCG were determined in serum. For the validation specificity, linearity, recovery, precision and the quantification limit were evaluated. In vivo, concentrations of both compounds were determined in 15 controls and 77 haemodialysis patients, as well as protein binding in the dialysed group and the reduction ratios during haemodiafiltration. In addition, the in vitro effect of the solutes on leucocyte free radical production at measured concentrations was assessed. RESULTS: A fast and accurate HPLC method was developed to simultaneously quantify pCS and pCG. Both conjugates are retained in uraemia with a substantially higher total serum pCS in comparison to pCG (31.4 ± 15.8 versus 7.3 ± 6.5 mg/L) but also a substantial difference in protein binding (92.4 ± 3.0 versus 8.3 ± 4.4%) and in reduction ratio during post-dilution haemodiafiltration (37.4 ± 7.1 versus 78.6 ± 6.4%). pCG per se has no effect on leucocyte oxidative burst activity, whereas in combination with pCS, a synergistic activating effect was observed. CONCLUSIONS: Serum concentrations of pCS and pCG are elevated in uraemia. Both conjugates show a different protein binding, resulting in a different dialytic behaviour. Biologically, both conjugates are synergistic in activating leucocytes.

Factors determining yield and quality of illicit indoor cannabis (Cannabis spp.) production.

Judiciary currently faces difficulties in adequately estimating the yield of illicit indoor cannabis plantations. The latter data is required in penalization which is based on the profits gained. A full factorial experiment in which two overhead light intensities, two plant densities and four varieties were combined in the indoor cultivation of cannabis (Cannabis spp.) was used to reveal cannabis drug yield and quality under each of the factor combinations. Highest yield was found for the Super Skunk and Big Bud varieties which also exhibited the highest concentrations of Δ(9)-tetrahydrocannabinol (THC). Results show that plant density and light intensity are additive factors whereas the variety factor significantly interacts with both plant density and light intensity factors. Adequate estimations of yield of illicit, indoor cannabis plantations can only be made if upon seizure all factors considered in this study are accounted for.

Comparison of removal capacity of two consecutive generations of high-flux dialysers during different treatment modalities.

BACKGROUND: Innovative modifications have been introduced in several types of dialyser membranes to improve adequacy and permselectivity. Which aspects of removal are modified and how this relates to different diffusive or convective strategies has, however, been insufficiently investigated. METHODS: In a prospective cross-over study, 14 chronic kidney disease (Stage 5D) patients were dialysed with a second-generation high-flux dialyser (Polynephron) in comparison to a first-generation type (DIAPES-HF800). Both dialysers were assessed in haemodialysis, in online pre-dilution and in post-dilution haemodiafiltration. Reduction ratio (RR, %) of small water-soluble compounds (urea and uric acid), low-molecular weight proteins (LMWPs) (ß(2)-microglobulin, cystatin C, myoglobin and retinol-binding protein) and protein-bound solutes (hippuric acid, indole acetic acid, indoxylsulphate and p-cresylsulphate) was assessed, together with albumin losses into the dialysate. RESULTS: Comparing the two types of membranes, the second-generation dialyser demonstrated a higher RR for LMWPs, whilst at the same time exhibiting lower albumin losses but only during post-dilution haemodiafiltration. No differences in RR were detected for both the small water-soluble and the protein-bound compounds. Comparing dialysis strategies, convection removed the same amount of solute or more as compared to diffusion. CONCLUSIONS: The second-generation membrane resulted in a higher removal of LMWPs compared to the first-generation membrane, but for the other solutes, differences were less prominent. Convection was superior in removal of a broad range of uraemic retention solutes especially with the first-generation membrane.

Prospective evaluation of the change of predialysis protein-bound uremic solute concentration with postdilution online hemodiafiltration.

Although protein-bound uremic compounds have been related to outcome in observational studies, few current dialysis strategies provide more removal of those compounds than standard hemodialysis. We evaluated the evolution of protein-bound uremic solutes after a switch from high-flux hemodialysis to postdilution hemodiafiltration (n = 13). We compared predialysis solute concentration at 4, 5, and 9 weeks versus baseline for several protein-bound compounds and water-soluble solutes, as well as for beta(2)-microglobulin. After 9 weeks of postdilution hemodiafiltration, a significant decrease versus baseline could be detected for total concentration of protein-bound solutes: p-cresylsulfate (3.98 +/- 1.51-3.17 +/- 1.77 mg/dL, -20%, P < 0.01) and 3-carboxyl-4-methyl-5-propyl-2-furanpropionic acid (0.72 +/- 0.52-0.64 +/- 0.46 mg/dL, -11%, P < 0.01). For the other protein-bound solutes, hippuric acid, indoleacetic acid, and indoxylsulfate, no change in total concentration could be detected. The concentration of the middle molecule, beta(2)-microglobulin, decreased as well after 9 weeks of postdilution hemodiafiltration (24.7 +/- 9.3-18.1 +/- 6.7 mg/L, -27%, P < 0.01). For water-soluble compounds, no significant change of concentration was found. Postdilution hemodiafiltration in comparison to high-flux hemodialysis provided significant reduction of predialysis concentration of protein-bound compounds, especially those with the highest protein binding, and of beta(2)-microglobulin, by -11 to -27% in 9 weeks.

Serological cardiovascular and mortality risk predictors in dialysis patients receiving sevelamer: a prospective study.

BACKGROUND: Cardiovascular morbidity and mortality are massively increased in patients with chronic kidney disease (CKD). Sevelamer hydrochloride has been shown to attenuate cardiovascular calcifications in CKD and end-stage renal disease (ESRD) patients. We assessed how sevelamer hydrochloride influences the evolution of serum fetuin-A and other serological factors predicting cardiovascular outcome and survival in haemodialysis patients. METHODS: Fifty-seven prevalent haemodialysis patients were included in a three-phase prospective interventional trial (A-B-A design; 8 weeks per phase). Sevelamer was only administered in the middle phase of the study. Within the other two phases, >or=90% of the patients received calcium acetate for phosphate binding. Detailed time courses of serum biochemistries were analysed in order to obtain detailed insight into the influence of sevelamer upon CKD-mineral and bone disorder (MBD) parameters as well as serum fetuin-A, fibroblast growth factor 23 (FGF23) and uraemic toxin levels [uric acid, indoxyl sulphate, hippuric acid, indole acetic acid, p-cresol and 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid (CMPF)]. RESULTS: Forty-one patients finished the three prospective study phases (intention-to-treat analysis). After treatment with sevelamer, serum fetuin-A significantly increased (+21%), showing a delayed increase outlasting the third (non-sevelamer) study period. Total and low-density lipoprotein (LDL) cholesterol levels, as well as serum calcium, decreased significantly. The opposite occurred with albumin, C-reactive protein and intact parathyroid hormone (iPTH). FGF23, uric acid, indoxyl sulphate, hippuric acid, indole acetic acid, CMPF and serum phosphate did not change significantly during sevelamer treatment. In contrast, in parallel to sevelamer treatment, there was a significant rise in serum P-cresol. CONCLUSIONS: In haemodialysis patients, treatment with sevelamer over 8 weeks was associated with a delayed yet long-lasting increase in serum fetuin-A levels. Increasing the serum level of fetuin-A, a negative acute-phase protein and systemic calcification inhibitor, might be one of the potential anti-calcification mechanisms of sevelamer. Since we failed to detect a decrease in systemic inflammation and uraemic toxins, the exact mechanisms by which sevelamer treatment affects serum fetuin-A remain to be determined.

Free p-cresylsulphate is a predictor of mortality in patients at different stages of chronic kidney disease.

BACKGROUND: Uraemic toxins are considered to be emerging mortality risk factors in chronic kidney disease (CKD) patients. p-Cresol (a prototype protein-bound uraemic retention solute) has been shown to exert toxic effects in vitro. Recently, it has been demonstrated that p-cresol is present in plasma as its sulphate conjugate, p-cresylsulphate. The present study evaluated the distribution of free and total p-cresylsulphate and sought to determine whether these parameters were associated with vascular calcification, arterial stiffness and mortality risk in a cohort of CKD patients. METHODS: One hundred and thirty-nine patients (mean +/- SD age: 67 +/- 12; males: 60%) at different stages of CKD (8% at Stage 2, 26.5% at Stage 3, 26.5% at Stage 4, 7% at Stage 5 and 32% at Stage 5D) were enrolled in this study. RESULTS: Baseline total and free p-cresylsulphate presented an inverse relationship with renal function and were significantly associated with vascular calcification. During the study period (mean follow-up period: 779 +/- 185 days), 38 patients died [including 22 from cardiovascular (CV) causes]. In crude survival analyses, free (but not total) p-cresylsulphate was shown to be a predictor of overall and CV death. Higher free p-cresylsulphate levels (>0.051 mg/100 mL; median) were associated with mortality independently of well-known predictors of survival such as age, vascular calcification, anaemia and inflammation. CONCLUSIONS: Serum levels of free and total p-cresylsulphate (the main in vivo circulating metabolites of p-cresol) were elevated in later CKD stages. However, only free p-cresylsulphate seems to be a predictor of survival in CKD.

Serum indoxyl sulfate is associated with vascular disease and mortality in chronic kidney disease patients.

BACKGROUND AND OBJECTIVES: As a major component of uremic syndrome, cardiovascular disease is largely responsible for the high mortality observed in chronic kidney disease (CKD). Preclinical studies have evidenced an association between serum levels of indoxyl sulfate (IS, a protein-bound uremic toxin) and vascular alterations. The aim of this study is to investigate the association between serum IS, vascular calcification, vascular stiffness, and mortality in a cohort of CKD patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: One-hundred and thirty-nine patients (mean +/- SD age: 67 +/- 12; 60% male) at different stages of CKD (8% at stage 2, 26.5% at stage 3, 26.5% at stage 4, 7% at stage 5, and 32% at stage 5D) were enrolled. RESULTS: Baseline IS levels presented an inverse relationship with renal function and a direct relationship with aortic calcification and pulse wave velocity. During the follow-up period (605 +/- 217 d), 25 patients died, mostly because of cardiovascular events (n = 18). In crude survival analyses, the highest IS tertile was a powerful predictor of overall and cardiovascular mortality (P = 0.001 and 0.012, respectively). The predictive power of IS for death was maintained after adjustment for age, gender, diabetes, albumin, hemoglobin, phosphate, and aortic calcification. CONCLUSIONS: The study presented here indicates that IS may have a significant role in the vascular disease and higher mortality observed in CKD patients.

Evolution of protein-bound uraemic solutes during predilution haemofiltration.

BACKGROUND: Protein-bound uraemic toxins provoke multiple biological changes involved in uraemia. Few if any dialytic strategies remove these compounds. METHODS: In this post hoc analysis of remnant samples from a randomised controlled trial, we evaluate whether predilution haemofiltration (HF) decreases the pretreatment concentration of protein- bound uraemic solutes. Patients treated with low-flux haemodialysis (HD) were enrolled into a group continuing this strategy (group A, n=8) over 6 months, whereas group B (n=12) was switched to predilution online HF. Blood was sampled at baseline and after 6 months to determine total and free concentration and percentage binding of indoxyl sulfate (IS), indole-3-acetic acid (IAA), hippuric acid (HA), p-cresol (PC) and 3-carboxy- 4-methyl-5-propyl-2-furanpropionic acid (CMPF). RESULTS: Comparing concentrations at start versus 6 months of treatment by paired analysis, HD had no impact. In contrast, at the end of the HF period, we found a decrease in total and free PC, free IAA and total CMPF. In addition, the percentage protein binding of IAA increased significantly. However, unpaired analysis revealed no statistical difference between HD and HF, both at baseline and after 6 months of treatment for all compounds. CONCLUSIONS: Paired analysis showed a beneficial impact of predilution online HF for several proteinbound uraemic solutes. Unpaired analysis, however, showed no statistical difference.

Effective removal of protein-bound uraemic solutes by different convective strategies: a prospective trial.

BACKGROUND: Although different on-line convective removal strategies are available, there are no studies comparing the efficiency of solute removal for the three main options [post-dilution haemodiafiltration (post-HDF), pre-dilution haemodiafiltration (pre-HDF) and pre-dilution haemofiltration (pre-HF)] in parallel. METHODS: In this study, we compared post-HDF (Polyflux 170), pre-HDF (Polyflux 170) and pre-HF (Polyflux 210) in 14 patients. Parallelism of the evaluation protocols consisted in applying the same blood flow, dialysis time and effective convection (22.9 +/- 1.7 versus 22.2 +/- 2.0 L, P = NS) in pre-HDF versus post-HDF, and the same blood flow and dialysis time while comparing pre-HDF and pre-HF (1:1 dilution). With pre-HF, ultrafiltration was maximized and resulted in an effective convective volume of 28.5 L. We studied water-soluble compounds (urea, creatinine, uric acid), protein-bound compounds (hippuric acid, indole acetic acid, indoxylsulfate and p-cresylsulfate) and beta(2)-microglobulin (beta(2)M). RESULTS: Post-HDF was superior to pre-HDF for water-soluble compounds and beta(2)M, whereas there was no difference for protein-bound compounds. Pre-HDF was superior to pre-HF for water-soluble compounds and protein-bound compounds. In contrast, removal of beta(2)M for pre-HF was higher than for pre-HDF, but it did not differ from that obtained with post-HDF. CONCLUSIONS: It is concluded that post-dilution is superior to pre-dilution HDF under conditions of similar convective volume, and that HDF is superior to HF in pre-dilution, with the exception of removal of beta(2)M. Overall, post-HDF is the most efficient convective strategy among those tested.

Evaluation of urine proteome pattern analysis for its potential to reflect coronary artery atherosclerosis in symptomatic patients.

Coronary artery disease (CAD) is a major cause of mortality and morbidity. Noninvasive proteome analysis could guide clinical evaluation and early/preventive treatment. Under routine clinical conditions, urine of 67 patients presenting with symptoms suspicious for CAD were analyzed by capillary electrophoresis directly coupled with mass spectrometry (CE-MS). All patients were subjected to coronary angiography and either assigned to a CAD or non-CAD group. A training set of 29 patients was used to establish CAD and non-CAD-associated proteome patterns of plasma as well as urine. Significant discriminatory power was achieved in urine but not in plasma. Therefore, urine proteomic analysis of further 38 patients was performed in a blinded study. A combination of 17 urinary polypeptides allowed separation of both groups in the test set with a sensitivity of 81%, a specificity of 92%, and an accuracy of 84%. Sequencing of urinary marker peptides identified fragments of collagen alpha1 (I and III), which we furthermore demonstrated to be expressed in atherosclerotic plaques of human aorta. In conclusion, specific CE-MS polypeptide patterns in urine were associated with significant CAD in patients with angina-typical symptoms. These promising findings need to be further evaluated in regard to reliability of a urine-based screening method with the potential of improving the diagnostic approaches for CAD.

Inconsistency of reported uremic toxin concentrations.

Discrepancies in reported uremic toxin concentrations were evaluated for 78 retention solutes. For this analysis, 378 publications were screened. Up to eight publications per toxin were retained. The highest and the lowest reported concentrations, as well as the median reported concentration were registered. The ratio between the highest and the lowest (H/L) concentrations and, for some solutes, also the ratio between the highest and the median (H/M) concentrations were calculated. The compounds were arbitrarily subdivided into three groups based on their H/L ratio: group A, H/L < 3 (n = 33); group B, 3 < H/L < 8.5 (n = 20); and group C, H/L > 8.5 (n = 25). Solutes of groups A and B showed a low to intermediate scatter, suggesting a homogeneity of reported data. Group C showed a more substantial scatter. For at least 10 compounds of group C, extremely divergent concentrations were registered (H/M > 5.5) using scatter plot analysis. For all solutes of groups A and B, the highest reported concentration could be used as a reference. For some solutes of group C and for the compounds showing a divergent scatter analysis, however, more refined directives should be followed.

Overestimation of advanced oxidation protein products in uremic plasma due to presence of triglycerides and other endogenous factors.

BACKGROUND: Advanced oxidation protein products (AOPP), a suggested protein biomarker of oxidative stress, are elevated in patients with chronic kidney disease (CKD), who also often suffer from hypertriglyceridemia. METHODS: The analysis included plasma AOPP, TG, cholesterol, albumin and total protein, inflammation and oxidative stress markers from healthy subjects, non-dialyzed CKD, HD and CAPD patients. We studied, at two different European centres, effects of a meal, comparison between serum and plasma, L-index (indicating turbidity), spiking with fat and protein, and centrifugation on the AOPP concentrations. AOPP was measured at 340 nm and expressed as chloramine-T equivalents. RESULTS: AOPP correlated with TG levels not only in CKD patients, but also in healthy subjects. Weak to absent correlations were observed between AOPP and markers of inflammation and oxidative stress in CKD patients. A meal increased the TG levels several-fold paralleled by a rise in measured AOPP to patient levels. Spiking of the plasma with Intralipid or protein resulted in increased absorbances at 340 nm, due to turbidity or real absorbance, while centrifugation similarly decreased the apparent AOPP and TG levels. CONCLUSIONS: AOPP concentration, especially due to the influence of turbidity at all levels of TG concentration, but also due to other factors on top of TG, is overestimated in all plasma samples, including controls at fasting and non-fasting conditions. Thus, AOPP is a questionable biomarker of oxidative stress and inflammation in CKD patients.

P-cresylsulphate, the main in vivo metabolite of p-cresol, activates leucocyte free radical production.

BACKGROUND: Chronic renal insufficiency is associated with the retention of solutes normally excreted by healthy kidneys. P-cresol, a prototype protein-bound uraemic retention solute, has been shown to exert toxic effects in vitro. Recently, however, it has been demonstrated that p-cresol in the human body is conjugated, with p-cresylsulphate as the main metabolite. METHODS: The present study evaluates the effect of p-cresylsulphate on the respiratory burst activity of leucocytes. RESULTS: P-cresylsulphate significantly increased the percentage of leucocytes displaying oxidative burst activity at baseline. Oxidative burst activity of stimulated leucocytes was however not affected. In contrast, p-cresol had no effect on the leucocytes at baseline, but inhibited leucocytes burst activity after stimulation. CONCLUSION: The present study demonstrates, for the first time, that p-cresylsulphate, the main in vivo metabolite of p-cresol, has a pro-inflammatory effect on unstimulated leucocytes. This effect could contribute to the propensity to vascular disease in the uraemic population.

Sevelamer prevents uremia-enhanced atherosclerosis progression in apolipoprotein E-deficient mice.

BACKGROUND: The novel phosphate binder sevelamer has been shown to prevent the progression of aortic and coronary calcification in uremic patients. Whether it also decreases the progression of atheromatous plaques is unknown. The aim of our study was to examine the effect of sevelamer administration on the development of atherosclerosis and aortic calcification in the uremic apolipoprotein E-deficient mouse as an established model of accelerated atherosclerosis. METHODS AND RESULTS: Female mice were randomly assigned to 4 groups: 2 groups of nonuremic mice (sevelamer versus control) and 2 groups of uremic mice (sevelamer versus control). Sevelamer was given at 3% with chow. The increases in serum phosphorus concentration and calcium-phosphorus product observed in uremic control mice were prevented by sevelamer. Serum total cholesterol was increased in the 2 uremic mouse groups and remained unchanged in response to sevelamer. After 8 weeks of sevelamer treatment, uremic mice exhibited a significantly lower degree of atherosclerosis (P<0.001) and vascular calcification than uremic control mice. Of interest, sevelamer exerted an effect on both intima and media calcification (P=0.005) in uremic mice. Among possible mechanisms involved, we found no evidence for the modulation by sevelamer of inflammation or selected uremic toxins. In contrast, nitrotyrosine staining as a measure of oxidative damage was significantly decreased in response to sevelamer treatment in control and uremic mice (P<0.005). CONCLUSIONS: Sevelamer delays not only vascular calcification but also atherosclerotic lesion progression in uremic apolipoprotein E-deficient mice. It opens the possibility of a cholesterol-independent action of sevelamer on atheroma formation via effects on mineral metabolism, oxidative stress, or both.

Pre-dilution on-line haemofiltration vs low-flux haemodialysis: a randomized prospective study.

BACKGROUND: Accumulation of larger molecular weight uraemic toxins molecules may have a negative effect on the cardiovascular and nutritional state of dialysis patients and influence uraemic symptomatology. Their clearance can be enhanced by the use of haemofiltration (HF). METHODS: The effects of low-flux haemodialysis (HD) (ultrapure dialysate; polyamide membranes) and pre-dilution on-line HF (1:1 blood/substitution ratio; target filtration volume: 1.2 times body weight) on cardiovascular and nutritional parameters, interdialytic levels of uraemic toxins and quality of life (QOL; Laupacis questionnaire) were assessed during 1 year follow-up. Forty patients were randomized. RESULTS: After 1 year, 27 patients were eligible for analysis (HF: 13 patients; HD: 14 patients). Left ventricular mass index did not change in the HF patients (127+/-33 --> 131+/-36 g/m(2) after 12 months) or in the HD group (135+/-34 --> 138+/-32 g/m(2)). Also, there were no changes in pulse wave velocity, and 48 h systolic and diastolic blood pressures. Lean body mass, assessed by dual-energy X-ray absorptiometry, increased in the HF group (44.8+/-8.9 --> 46.2+/-9.6 kg; P<0.05), but not in the HD group (49.4+/-9.2 --> 50.6+/-8.8 kg), although differences between groups were not significant. Insulin-like growth factor-1 levels remained stable in the HF patients, but decreased in the HD group (P<0.05 between groups). QOL for physical symptoms improved in the HF group (4.2+/-1.2 --> 5.0+/-1.1; P<0.05 within the HF group and P = 0.06 between groups), but not in the HD group (4.0+/-1.0 --> 4.4+/-1.4). beta2-microglobulin, complement factor D and homocysteine decreased significantly in the HF but not in the HD group, whereas l-ADMA, leptin and advanced glycation end-products-related fluorescence did not change. CONCLUSIONS: No changes in cardiovascular parameters were observed during pre-dilution on-line HF compared with low-flux HD. Treatment with on-line HF resulted in marked changes in the uraemic toxicity profile, an improvement in physical well-being and a small improvement in nutritional state.