Severe 25E-NBOH intoxication associated with MDPHP intake: a case report, metabolism study, and literature review.

N-Benzylphenethylamine derivatives are 5-HT2A receptor agonists with hallucinogenic properties, including NBOMe (N-(2-methoxybenzyl)-2-(3,4,5-trimethoxyphenyl)ethan-1-amine) and NBOH (2-(((2,5-dimethoxyphenethyl)amino)methyl)phenol). We reported here the case of a 23-year-old man who presented a serotoninergic syndrome and a loss of consciousness following the consumption of a powder labelled as 25I-NBOH. Toxicological analyses of biological samples were carried out using a liquid chromatography high-resolution mass spectrometry. Two new psychoactive substances were identified and confirmed with certified reference materials: 25E-NBOH (2-(((4-ethyl-2,5-dimethoxyphenethyl)amino)methyl)phenol) and MDPHP (1-(benzo[d][1,3]dioxol-5-yl)-2-(pyrrolidin-1-yl)hexan-1-one). Pharmaceuticals administered to the patient during his medical care were found in plasma and urine. 25E-NBOH and MDPHP concentrations were respectively at 2.3 ng/mL and 3.4 ng/mL in plasma, and 25.7 ng/mL and 30.5 ng/mL in urine. 25I-NBOH (2-(((4-iodo-2,5-dimethoxyphenethyl)amino)methyl)phenol) was specifically searched in both samples and was not detected. These results are discussed along with a literature review on human cases of exposure to N-benzylphenethylamine derivatives. Using molecular networking approach, we propose the first 25E-NBOH metabolism study using authentic biological samples (plasma and urine). We described seven metabolites (M1 to M7), including two phase I (m/z 330.172; m/z 288.160) and five phase II metabolites (m/z 464.191, m/z 478.207, m/z 492.223, m/z 508.218; m/z 396.156). The M6 (m/z 492.223) was the most intense ion detected in plasma and urine and could be proposed as a relevant 25E-NBOH consumption marker. Overall, we described an original case of 25E-NBOH poisoning and identified metabolites that could potentially be used as consumption markers to detect 25E-NBOH intoxications with a higher confidence level and probably a longer detection window.

In silico and in vitro metabolism studies of the new synthetic opiate AP-237 (bucinnazine) using bioinformatics tools.

The recent emergence of new synthetic opioids (NSOs) compounds in the illicit market is increasingly related to fatal cases. Identification and medical care of NSO intoxication cases are challenging, particularly due to high frequency of new products and extensive metabolism. As the study of NSO metabolism is crucial for the identification of these drugs in cases of intoxication, we aimed to investigate the metabolism of the piperazine NSO AP-237 (= bucinnazine). Two complementary approaches (in silico and in vitro) were used to identify putative AP-237 metabolites which could be used as consumption markers. In silico metabolism studies were realized by combining four open access softwares (MetaTrans, SyGMa, Glory X, Biotransformer 3.0). In vitro experiments were performed by incubating AP-237 (20 µM) in differentiated HepaRG cells during 0 h, 8 h, 24 h or 48 h. Cell supernatant were extracted and analyzed by liquid chromatography coupled to high-resolution mass spectrometry and data were reprocessed using three strategies (MetGem, GNPS or Compound Discoverer®). A total of 28 phase I and six phase II metabolites was predicted in silico. Molecular networking identified seven putative phase I metabolites (m/z 203.154, m/z 247.180, m/z 271.180, two m/z 289.191 isomers, m/z 305.186, m/z 329.222), including four previously unknown metabolites. Overall, this cross-disciplinary approach with molecular networking on data acquired in vitro and in silico prediction enabled to propose relevant candidate as AP-237 consumption markers that could be added to mass spectrometry libraries to help diagnose intoxication.

Validation according to European and American regulatory agencies guidelines of an LC-MS/MS method for the quantification of free and total ropivacaine in human plasma.

Background Ropivacaine is a widely used local anaesthetic drug, highly bound to plasma proteins with a free plasma fraction of about 5%. Therefore, the monitoring of free drug concentration is most relevant to perform pharmacokinetic studies and to understand the drug pharmacokinetic/pharmacodynamic (PK/PD) relationship. Methods A high-sensitivity liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using reverse-phase LC and electrospray ionisation mass spectrometry with multiple reaction monitoring (MRM) is described for the quantitation of both free and total ropivacaine in human plasma. Ropivacaine-d7 was used as an internal standard (IS). Results The method was validated in the range 0.5-3000 ng/mL, with five levels of QC samples and according to the European Medicine Agency and Food and Drug Administration guidelines. The performance of the method was excellent with a precision in the range 6.2%-14.7%, an accuracy between 93.6% and 113.7% and a coefficient of variation (CV) of the IS-normalised matrix factor below 15%. This suitability of the method for the quantification of free and total ropivacaine in clinical samples was demonstrated with the analysis of samples from patients undergoing knee arthroplasty and receiving a local ropivacaine infiltration. Conclusions A method was developed and validated for the quantification of free and total ropivacaine in human plasma and was shown suitable for the analysis of clinical samples.

Hair analysis does not allow to discriminate between acute and chronic administrations of a drug in young children.

There are many differences between the hair from children and that of adult subjects, the hair being thinner, more porous with a different growth rate from the usual 1 cm/month observed in adults. In order to determine whether hair analysis could discriminate between chronic use and acute administration of a drug in children like in adults, we analyzed hair from 18 children aged between 1 day and 15 years in whom the administration of different drugs was known (single therapeutic administration or acute intoxication). A strand of hair was sampled within 1 to 45 days after treatment or intoxication. Analysis was conducted using LC/MS/MS. In the 10 youngest children, aged between 1 day and 29 months, the compounds administered in hospital or responsible for intoxication (lidocaine, ropivacaine, diazepam, midazolam, levetiracetam, morphine, ketamine, methadone, buprenorphine, THC, MDMA) were found in all segments of the hair independently of the time of sampling (1-45 days after ingestion). The concentrations detected were similar along the hair shaft, showing a radial diffusion and incorporation of the analytes in the hair of young children from the sebum. Concentrations could be very high when sampled shortly after administration (72 ng/mg for methadone, 75 ng/mg for MDMA after 3 days) and lower when sampling later (1.2 ng/mg for MDMA after 45 days). In these cases, hair analysis allowed to highlight the compounds responsible for intoxication even when they had disappeared from the blood or urine but should not be used to discriminate long-term exposure to a drug. In the eight remaining children aged from 34 months to 15 years, the drugs used in hospital (lidocaine, diazepam, morphine) or responsible for intoxication (THC, codeine, buprenorphine) were not found in any analyzed segments sampled 1 to 5 days after administration of the drugs, in agreement with the non-incorporation of the drugs from the sebum into the hair. For those children aged over 34 months, hair analysis allows to determine the chronic administration of a drug, like in adults.

Plasma 7-Hydroxymethotrexate Levels Versus Methotrexate to Predict Delayed Elimination in Children Receiving High-Dose Methotrexate.

BACKGROUND: The aim of this study was to investigate the correlation between 7-hydroxymethotrexate (7-OHMTX) and creatinine and to evaluate the predictive value of 7-OHMTX levels on delayed elimination at 24 and 48 hours. In addition, differences in methotrexate (MTX), 7-OHMTX levels, and MTX metabolism using the ratio MTX/7-OHMTX were determined according to age. METHODS: The authors included a total of 106 cycles, corresponding to 33 patients (mean age: 9.8 years, range: 2-18 years) suffering from acute lymphoblastic leukemia, non-Hodgkin lymphoma and osteosarcoma and receiving high-dose MTX (HD-MTX). Plasma MTX, 7-OHMTX, and creatinine at T24 and T48 hours were measured. RESULTS: Children older than 14 years had significantly higher MTX levels at T48 hours (1.25 versus 0.5 µmol/L, P < 0.05) and a higher MTX/7-OHMTX ratio (0.63 versus 0.20, P < 0.05) than children younger than 6 years. Plasma 7-OHMTX at T24 and T48 hours was positively correlated with serum creatinine and creatinine ratio at T24 and T48 hours. MTX levels provided a better specificity and sensitivity at both 24 and 48 hours than 7-OHMTX to predict delayed MTX elimination. A MTX threshold close to 0.83 µmol/L at T48 hours improved specificity from 58% to 82% and keeps sensitivity at 100%. The authors identified a cut-off at 65 µmol/L for MTX at T24 hours with a good sensitivity (75%) and specificity above 50%. CONCLUSIONS: These results confirm the concentration-dependent nephrotoxicity of 7-OHMTX. Children older than 14 years old had a higher MTX levels at 48 hours and a higher MTX/7-OHMTX ratio, suggesting a faster metabolism in younger children. This study identified a higher and more specific MTX threshold at T48 hours compared to those currently used, and a new threshold at T24 hours.

Detection and quantification of 12 anabolic steroids and analogs in human whole blood and 20 in hair using LC-HRMS/MS: application to real cases.

We developed and validated a method to detect and quantify 12 anabolic steroids in blood (androstenedione, dihydrotestosterone, boldenone, epitestosterone, mesterolone, methandienone, nandrolone, stanozolol, norandrostenedione, tamoxifene, testosterone, trenbolone) and eight more in hair samples (nandrolone phenylpropionate, nandrolone decanoate, testosterone propionate, testosterone benzoate, testosterone cypionate, testosterone decanoate, testosterone phenylpropionate, testosterone undecanoate) using liquid chromatography coupled to high-resolution mass spectrometry. This method used a benchtop Orbitrap mass spectrometer operating with an APCI probe under positive ionization mode. Analysis was realized in full scan experiment with a nominal resolving power of 140,000. After addition of the internal standard (testosterone-D3) and incubation in phosphate buffer pH = 5 for hair, 200 µL of blood and 30 mg of hair samples were extracted with heptane. LOQ and LOD were determined at 5 and 1 ng mL-1 in whole blood and 10 to 100 pg mg-1 and 2 to 20 pg mg-1 in hair according to the compounds, respectively. The method was linear in the 5-1000 ng mL-1 range in whole blood and between 10 or 100 pg mg-1 and 1000 pg mg-1 in hair with correlation coefficients >0.99, and intra- and inter-day accuracy and precision were <14.8% for all compounds except for some esters in hairs (<19.9%) probably due to an important matrix effect for these compounds. This sensitive and specific method to detect anabolic steroids has been successfully applied to two real cases, for which various anabolic steroids in whole blood, urine, and hair were identified and quantified.

Biomarkers for the diagnosis and monitoring of nitrous oxide intoxication: objectives and methodology of the SFBC Working Group.

The recreational use of nitrous oxide (N2O) is an emerging public health issue. Chronic N2O abuse may result in various clinical symptoms, encompassing neurological, psychiatric and cardiovascular outcomes. Despite the difficulties for the laboratory investigation of N2O intoxication, there is currently no guidelines in France to help both clinicians and biologists use appropriate biomarkers for the diagnosis and monitoring of patients with clinical symptoms potentially related to N2O intoxication. A multi-disciplinary Working Group, carried out under the auspices of the French Society of Clinical Biology (SFBC) and in collaboration with the French Societies of Emergency Medicine (SFMU), Analytical Toxicology (SFTA), Hemostasis and Thrombosis (SFTH), Vitamins and Biofactors (SFVB), and the French Federation of Neurology (FFN), was recently implemented to elaborate practical guidelines. The methodology of the Working Group is based on the critical analysis of the literature, and raising concerns and objectives are grouped into five working packages. The present manuscript primarily aims to expound upon the methodology and objectives of the ongoing SFBC Working Group on N2O.

A case of drug-facilitated sexual assault involving 3,4-methylenedioxy-methylamphetamine.

Typical scenarios of drug-facilitated sexual assaults usually involve victims having ingested a drink after which they had little, partial or no recollection of events for a period of time. We were surprised by the case of a woman who was sexually assaulted and described a state of amazement, leading to an incapacity to resist physically or verbally to her aggressor, and who remembered everything. Alcohol was first suspected but toxicological analysis revealed the presence of 3,4-methylene-dioxy-methylamphetamine (MDMA, Ecstasy). In the literature review, a few cases of sexual assault involving involuntarily MDMA intake are described.

Transdermal Nicotine Poisoning: A Rare Case Report of Occupational Exposure.

We report a case of accidental nicotine intoxication following transdermal exposure in a 22-year-old man with no medical history, who worked in a company manufacturing e-liquids for electronic cigarettes. He accidentally spilled 300 mL of pure nicotine solution (>99%) on his right leg without wearing protective clothing or a mask. Less than a minute later, he experienced dizziness, nausea, and headaches, followed by painful burning sensations in the affected area. He immediately removed his pants and washed his leg thoroughly with water. He presented to the emergency department two hours later, where he exhibited a respiratory rate of 25 cpm, a heart rate of 70 bpm, headaches, abdominal pain, pallor, and vomiting. He recovered without specific treatment five hours post-intoxication. Plasma levels of nicotine, cotinine, and hydroxycotinine were measured five hours after exposure using liquid chromatography-mass spectrometry. The concentrations found were 447 ng/mL for nicotine, 1254 ng/mL for cotinine, and 197 ng/mL for hydroxycotinine. Nicotine is an alkaloid that can be highly toxic, with doses of 30-60 mg being potentially fatal. Transdermal intoxication is rare, with very few cases reported in the literature. This case highlights the risk of acute intoxication through cutaneous exposure to nicotine-containing liquid products and the need for protective clothing when handling such products in a professional context.

Validation of a non-targeted method devoted to identification and quantitation of toxicologically relevant compounds in plasma with HRMS.

The objective of this study was to develop and validate a simple method using liquid chromatography hyphenated to high resolution mass spectrometry (HRMS) allowing both the performance of a non-targeted screening and the simultaneous quantification of 29 compounds of interest in clinical and forensic toxicology. Extraction was done with QuEChERS salts and acetonitrile, after addition of internal standard to 200 µL of human plasma samples. The mass spectrometer was an Orbitrap, with a heated electrospray ionization (HESI) probe. The analyses were carried out in full scan experiment with a nominal resolving power of 60,000 FWHM within the 125-650 m/z mass range, followed by four cycles of data dependent analysis (DDA) with a mass resolution of 16,000 FWHM. The untargeted screening was evaluated using 132 compounds, mean limit of identification (LOI) was 8.8 ng/mL (min = 0.05 ng/mL, max = 500 ng/mL) and mean limit of detection (LOD) was 0.25 ng/mL (min = 0.05 ng/mL, max = 5 ng/mL). The method was linear in the 5 to 500 ng/mL range (0.5 to 50 ng/mL for cannabinoids, 6-acetylmorphine and buprenorphine) with correlation coefficients > 0.99, intra- and inter-day accuracy and precision were < 15% for all compounds. The method was successfully applied to 31 routine samples.

Correlation between Saliva Levels and Serum Levels of Free Uremic Toxins in Healthy Volunteers.

The objective of the present study was to investigate the putative correlation between the saliva concentration and free serum concentration for 10 uremic toxins (UTs; eight protein-bound solutes: 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF), hippuric acid (HA), indole-3-acetic acid (3-IAA), indoxyl sulfate (I3S), kynurenic acid (KA), kynurenine (KYN), p-cresyl glucuronide (pCG), and p-cresyl sulfate (pCS); two free, water-soluble, low-molecular weight solutes: phenylacetylglutamine (PAGN) and trimethylamine N-oxide (TMAO); and three precursors: tyrosine (Tyr), phenylalanine, and tryptophan). Saliva samples and blood samples were collected simultaneously from 18 healthy volunteers. After the addition of internal standards, 50 µL of saliva or serum were precipitated with methanol. UTs and precursors were quantified using a validated LC-MS/MS method. The saliva-serum correlation was statistically significant (according to Spearman's coefficient) for six UTs (TMAO, HA, I3S, pCS, 3-IAA, and CMPF). Tyr presented a weak saliva-serum correlation (p = 0.08), whereas the other two precursors did not show a saliva-serum correlation. For three UTs (KYN, KA and pCG), we were unable to test the correlation since the saliva or serum levels were too low in many of the volunteers. The present study is the first to report on the saliva concentrations of TMAO, KYN, HA, PAGN, pCG, and 3-IAA.

Determination of cannabinoids content in light cannabis inflorescences sold in France.

In the last 2 years, the number of shops selling CBD-rich THC-deprived cannabis flowers (CrTd) has increased considerably in France as in many European countries. The objective of this study was to determine the actual composition of the samples sold in these stores and to discuss regulatory consequences that may affect users. Samples were provided from shops in the region Provence-Alpes Cote d'Azur (PACA), France. Pictures of the samples were taken before they were weighed then crushed. Twenty milligrams were diluted in 10 ml heptane ethyl acetate (7:1; v:v) for analysis by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method was validated according to SWGTOX guidelines for the quantification of cannabidiol (CBD), delta-9-tetrahydrocannabinol (THC) and cannabinol (CBN). Thirty-nine samples obtained between November 2021 and January 2022 in the PACA region were analyzed in this study. Mean content was 0.32% (0.03%-0.77%; STDV = 0.17%; n = 39) for THC, 2.23% (0.01%-5.97%; STDV = 1.29%; n = 39) for CBD and 0.01% (0.004%-0.025%; STDV = 0.01%; n = 19) for CBN. THC content over the threshold defined by the European legislation (>0.3%) was found in 18 of the 39 samples analyzed together with a CBD content <1% in nine samples (23%). None of the products analyzed had health risk messages on the packaging. The consumption of these products may lead to the presence of THC in biological fluids, which can be detected by screening. Users may then find themselves in breach of the law particularly when driving. Consumers should therefore be informed both about the actual composition of these products and about the legal and health risks they run.

Determination of Prenatal Substance Exposure Using Meconium and Orbitrap Mass Spectrometry.

The aim of this study was to develop and to validate a toxicological untargeted screening relying on LC-HRMS in meconium including the detection of the four main classes of drugs of abuse (DoA; amphetamines, cannabinoids, opioids and cocaine). The method was then applied to 29 real samples. Analyses were performed with a liquid chromatography system coupled to a benchtop Orbitrap operating in a data-dependent analysis. The sample amount was 300 mg of meconium extracted twice by solid phase extraction following two distinct procedures. Raw data were processed using the Compound Discoverer 3.2 software (Thermo). The method was evaluated and validated on 15 compounds (6-MAM, morphine, buprenorphine, norbuprenorphine, methadone, EDDP, amphetamine, MDA, MDMA, methamphetamine, cocaine, benzoylecgonine, THC, 11-OH-THC, THC-COOH). Limits of detection were between 0.5 and 5 pg/mg and limits of identification between 5 and 50 pg/mg. Mean matrix effect was between -79 and -19% (n = 6) and mean overall recovery between 18 and 73% (n = 6) at 100 pg/mg. The application allows the detection of 88 substances, including 47 pharmaceuticals and 15 pharmaceutical metabolites, cocaine and its metabolites, THC and its metabolites, and natural (morphine, codeine) and synthetic (methadone, buprenorphine, tramadol, norfentanyl) opioids. This method is now used routinely for toxicological screening in high-risk pregnancies.

Analysis of pharmaceutical products and dietary supplements seized from the black market among bodybuilders.

Substandard/counterfeit drugs are a growing global problem. According to the World Health Organisation, counterfeit medicines are medicines that are mislabelled deliberately and fraudulently regarding their identity and/or source. In high income countries, drugs seized are mainly represented by performance and image enhancing drugs (PIEDs). The aim of this study was to present the qualitative and quantitative results of toxicological analyses of pharmaceutical and dietary supplements seized from the black market among bodybuilders in France. All dietary supplements and pharmaceuticals seized from the black market and addressed to the laboratory for a qualitative and quantitative analysis between January 2016 and December 2019 were included in the study. A screening was carried out by gas chromatography-mass spectrometry and liquid chromatography-high resolution mass spectrometry. Identified compounds were quantified by liquid chromatography-tandem mass spectrometry. One hundred and ten products were seized and submitted to the laboratory for identification of active compounds and quantification: 75 pharmaceuticals and 35 dietary supplements. This included 39 oily and 3 aqueous solutions for intramuscular injection, 34 tablets, 13 capsules, 14 powders, 4 liquids and 3 lyophilizates. Among the pharmaceuticals, 25/75 (33%) were substandard (dosage not on the acceptable range defined for original products), 24/75 (32%) were counterfeit (qualitative formulation does not match the label) and 14/75 (19%) were original (qualitative formulation and levels of active ingredients fully matches the declared formulation. The analysis of the 12 remaining products revealed a correct qualitative content for 11/75 (15%), but quantitation could not be carried out because of the lack of reference standards at the time of the analysis. Fifty-four pharmaceuticals contained anabolic-androgenic steroids (AAS). Four out of 54 (7.4%) AAS were found as original, 8/54 (15%) could not be quantified (one with wrong active ingredient), corresponding to 43/54 (80%) AAS being non-original. In contrast, only 1/35 dietary supplement (3%) was adulterated, with a doping substance (1,3-dimethylbutylamine, DMBA). This work allows to show that France is not spared by the trafficking of PIEDs. The use of counterfeit drugs in mainstream population is an underestimated public health issue.

Unintentional cannabis poisoning in toddlers: A one year study in Marseille.

France is the country with the highest prevalence of cannabis use in Europe, despite the fact that cannabis has not been legalized. This prevalence is still increasing along with THC content in cannabis products. In the meantime, unintentional cannabis poisoning by ingestion in toddlers is constantly rising. The aim of this study was to document children's cannabis poisoning biologically and clinically. Plasma and urine samples were extracted by solid phase extraction and analyzed by liquid chromatography coupled to tandem mass spectrometry. Children under 4 years old admitted in pediatric emergency departments for cannabis intoxication between February 1st 2019 and January 31st 2020 were included in this study. Twenty-six children were included (14 female and 12 male), the mean age was 17 months (10-41 months). THC, 11-OH-THC and THC-COOH plasma concentrations ranged from 2.9 to 93 ng/mL, 2.6-65 ng/mL and 29-914 ng/mL, respectively. The most frequent symptoms were drowsiness and hypotonia. Six critical cases were observed: 5 coma and 1 respiratory depression. All children having THC plasma concentrations over 60 ng/mL were in coma. Cannabis poisoning in toddlers become more frequent, 9 cases/year were reported in Marseille in 2007 and 26 cases/year in this study. There is a rising in severe clinical cases, particularly coma. These observations could be explained by an increase in THC content in cannabis products, and a trivialization of cannabis consumption. The unintentional ingestion of cannabis by children is a serious public health concern, and cannabis legalization could worsen this problem.

Molecular adsorbent recirculating system (MARS) and continuous veno-venous hemodiafiltration (CVVHDF) for diltiazem removal: An in vitro study.

The objective of the present study was to evaluate the efficacy of the molecular adsorbent recirculating system (MARS) vs continuous veno-venous hemodiafiltration (CVVHDF). Diltiazem poisoning was simulated in a central compartment consisting in a 5L dialysis solute spiked with diltiazem at two different toxic concentrations: 750 and 5000 µg/L. For CVVHDF, mean extraction coefficients (EC = (in concentration - out concentration)/in concentration) were concentration-dependent with a decrease all along the dialysis. At the end of the sessions the mean amounts remaining in the central compartment were 8% and 7% of the initial dose at 750 and 5000 µg/L, respectively. The mean cumulative amounts found in the effluent were 60% and 75% of the initial dose, respectively. The missing amounts accounted for 32% and 18% of the initial dose, respectively, corresponding to an adsorption to the dialysis membrane. In contrast, the different compartments of the MARS resulted in undetectable output concentration earlier that the end of the session. The mean concentrations of diltiazem remaining in the central compartment were <1 µg/L at the end of the sessions. Global ECs were around 50% all along the experiment at both concentrations, and the average charcoal cartridge ECs was 80% throughout the experiments.CVVHDF system in the developed model was efficient for diltiazem removal, mainly by diffusion, convection and to a lesser extent by adsorption to the dialysis membrane. In MARS system, resin cartridge and hemodialysis components are ineffective, charcoal cartridge is responsible for almost all drug removal.

Pro-calcifying analysis of uraemic serum from patients treated with medium cut-off membrane in a prospective, cross-over study.

BACKGROUND: The retention of a large number of solutes that are normally excreted or metabolized by the kidney is responsible for the symptoms typical in uraemic patients. These molecules are defined as uraemic toxins and can be classified into three groups: small water-soluble molecules, middle molecules and protein-bound toxins. Recently, efforts were put towards developing dialysis membranes that allow the removal of large middle molecules without clinically relevant albumin loss. These membranes are the medium cut-off (MCO) membranes that allow the removal of middle molecules up to ∼50 000 Da. METHODS: We performed a prospective, open-label, controlled, cross-over pilot study comparing expanded haemodialysis (HDx) (novel MCO membrane Theranova 400) and conventional haemodialysis (HD) in 20 prevalent HD patients. Ten patients used conventional HD high-flux dialyser and 10 patients used HDx for 3 months; later the patients switched and received the other treatment for a further 3 months. We then analysed the pro-calcifying effect of uraemic serum in a model of high phosphate(Pi)-induced calcification in vascular smooth muscle cells (VSMCs). RESULTS: In this study, every patient was the control of himself and, interestingly, we found a tendency of less pro-calcifying potential from HDx-treated patients' serum compared with HD. Studying pathogenetic processes involved in high Pi-induced calcium deposition, we found that uraemic serum of HDx-treated patients induced less VSMC necrosis compared with uraemic serum of HD patients. Nevertheless, no differences were found between the different dialytic treatments in the serum potential to induce apoptosis and to modulate the expression of a panel of genes involved in VSMC simil-osteoblastic differentiation such as bone morphogenetic protein 2, runt-related transcription factor 2, osteocalcin, matrix Gla protein, osteopontin, elastin and collagen I α1. In an effort to characterize the difference in uraemic toxin profile during the two different dialytic treatments, we measured a panel of 10 uraemic toxins and 3 precursors, finding a significant increased removal during HDx of 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid, tryptophane and some of its metabolites, such as 3-indoxyl sulphate, indole 3-acetic acid and kynurenine. CONCLUSIONS: These preliminary data are promising, although larger patients' groups are needed to better understand the effects of HDx on vascular calcification.

Quantification of free and protein bound uremic toxins in human serum by LC-MS/MS: Comparison of rapid equilibrium dialysis and ultrafiltration.

The objectives of this study were (1) to develop a method for the determination of 10 uremic toxins (3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF), hippuric acid, indole-3-acetic acid, indoxyl sulfate, kynurenic acid, kynurenine, p-cresyl glucuronide, p-cresyl sulfate, phenylacetylglutamine and trimethylamine N-oxide (TMAO)), and 3 precursors (tyrosine, phenylalanine, tryptophan) in serum and (2) to compare two separation methods to determine the free serum fraction: rapid equilibrium dialysis (RED) and ultrafiltration (UF). The method was developed on a liquid chromatography system coupled to a tandem mass spectrometer. Fifty µL of serum sample were precipitated with methanol after addition of internal standard. The two separation methods were compared using serum samples from patients suffering from renal impairment (n = 30). The method has been validated according to the European Medicines Agency (EMA) guidelines. Calibration curves were linear from 1 to 50 ng/mL up to 10,000-50,000 ng/mL according to the compounds. The comparison between the two separation methods produced similar results for all compounds except kynurenine, tryptophan (around 30% more with UF) and indole-3-acetic acid (around 30% more with RED). This study has allowed the development and validation of a sensitive and robust assay for the quantification of free and total concentrations of 10 uremic toxins and 3 precursors in human serum.

Development and validation of a liquid chromatography-tandem mass spectrometry method for simultaneous detection of 10 illicit drugs in oral fluid collected with FLOQSwabs™ and application to real samples.

According to French law, the roadside testing for drugs of abuse (DOA) should be performed in oral fluid (OF) using an immunological screening kit. If the screening is positive, confirmation has to be done in OF collected by a special swab, called the FLOQSwab™ (FS). Unlike other sampling kits, this device was not designed to collect OF since it does not contain an elution buffer. An analytical method was developed for the simultaneous detection of 10 DOA under control in France: tetrahydrocannabinol (THC) at 1 ng/mL, and cocaine, benzoylecgonine (BZE), morphine, 6-monoacetylmorphine (6-MAM), amphetamine, methamphetamine, 3,4-methylenedioxy-N-ethylamphetamine (MDEA), 3,4-methylenedioxyamphetamine (MDA), and 3,4-methylenedioxy-N-methylamphetamine (MDMA) at 10 ng/mL. Samples were eluted using the Quantisal® buffer and extracted by liquid-liquid extraction for THC and by solid-phase extraction for the remaining analytes. Analyses were performed by ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The validated method made it possible to detect the concentrations required by law and was successfully applied to samples from drivers who screened positive. The main limitations of this kit are the large variability of the collected OF volume and the poor stability of DOA in OF, requiring the use of a conservation buffer.

Does the Administration of Sevelamer or Nicotinamide Modify Uremic Toxins or Endotoxemia in Chronic Hemodialysis Patients?

BACKGROUND: Hyperphosphatemia control is a major issue in hemodialysis patients. Both sevelamer and nicotinamide are prescribed for this purpose. In addition, they exert pleiotropic effects such as an improvement of inflammatory status and potentially enhanced clearance of uremic toxins. In the present secondary analysis of the NICOREN trial, we investigated the impact of sevelamer and nicotinamide on uremic toxins, toxin precursors, and endotoxemia in chronic hemodialysis patients. METHODS: Circulating uremic toxins (including phenylacetylglutamine, trimethylamine-N-oxide, p-cresyl sulfate, indoxyl sulfate, kynurenine, hippuric acid, indole-3-acetic acid, 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid, kynurenic acid, and p-cresyl glucuronide) and precursors were measured by ultra-performance liquid chromatography-tandem mass spectrometry, and urea, uric acid, phosphate, C-reactive protein, and intact parathyroid hormone by routine biochemistry methods. Serum endotoxin (evaluated by lipopolysaccharide levels) and C-terminal fibroblast growth factor-23 levels were measured using enzyme-linked immunosorbent assay kits. RESULTS: One hundred hemodialysis patients were randomized to receive either nicotinamide or sevelamer treatment. Among them, 63% were male, mean (± standard deviation) age was 65 ± 14 years, 47% had diabetes mellitus, and 51% had a history of cardiovascular disease. In the sevelamer group, but not the nicotinamide group, serum levels of urea, uric acid, and fibroblast growth factor-23 were significantly reduced after 6 months of treatment. The other circulating uremic toxins and toxin precursors remained unchanged in response to either phosphate-lowering agent. Sevelamer treatment led to a marked decrease in serum lipopolysaccharide (p < 0.001) whereas nicotinamide treatment induced an only modest decrease of borderline significance (p = 0.057). There was no change in C-reactive protein levels. CONCLUSION: In contrast to sevelamer, nicotinamide did not reduce circulating levels of low-molecular-weight uremic toxins other than phosphate, and neither agent reduced circulating uremic toxins of high-molecular-weight or protein-bound toxins. Sevelamer, but not nicotinamide, reduced serum endotoxin levels. Despite no change in serum C-reactive protein, the endotoxin-lowering effect of sevelamer may help to attenuate the inflammatory status of patients with chronic kidney disease.