Area under the curve of tacrolimus using microsampling devices: towards precision medicine in solid organ transplantation?

PURPOSE: Therapeutic drug monitoring of tacrolimus using trough concentration (Cmin) is mandatory to ensure drug efficacy and safety in solid organ transplantation. However, Cmin is just a proxy for the area under the curve of drug concentrations (AUC) which is the best pharmacokinetic parameter for exposure evaluation. Some studies suggest that patients may present discrepancies between these two parameters. AUC is now easily available through mini-invasive microsampling approach. The aim of this study is to evaluate the relationship between AUC and Cmin in patients benefiting from a complete pharmacokinetic profile using a microsampling approach. METHODS: Fifty-one transplant recipients benefited from a complete pharmacokinetic profile using a microsampling approach, and their 24-h AUC were calculated using the trapezoidal method. The correlation with Cmin was then explored. In parallel, we estimated AUC using the sole Cmin and regression equations according to the post-transplantation days and the galenic form. RESULTS: Weak correlations were found between 24-h AUC observed and the corresponding Cmin (R2 = 0.60) and between AUC observed and expected using the sole Cmin (R2 = 0.62). Therapeutic drug monitoring of tacrolimus using Cmin leads to over- or under-estimate drug exposure in 40.3% of patients. CONCLUSION: Tacrolimus Cmin appears to be an imperfect reflection of drug exposure. Evaluating AUC using a microsampling approach offers a mini-invasive strategy to monitor tacrolimus treatment in transplant recipients.

Mise en évidence d'intoxications par ingestion de champignons supérieurs : expérience au CHU de Rennes.

L'α- et la ß-amanitine sont de puissantes toxines de champignons supérieurs responsables de cytolyses hépatiques graves pouvant menacer le pronostic vital. En France, les données des centres antipoison rapportent un nombre croissant d'intoxications aux champignons depuis 2016, justifiant le besoin de méthodes de diagnostic biologique robustes. En laboratoire de toxicologie hospitalière, l'objectivation d'une intoxication par les amanitines à partir de prélèvements sanguins ou urinaires constitue ainsi un élément important dans la prise en charge du patient intoxiqué. L'objectif de ce travail consiste à réaliser une mini-revue de la littérature sur le dosage des amanitines dans les fluides biologiques pour le diagnostic des intoxications aux amanitines. Les caractéristiques des amanitines, les méthodes analytiques, les données d'interprétation, les applications pratiques ainsi que les perspectives d'utilisation des techniques de dosage y sont présentées. À travers une comparaison de deux techniques analytiques de chromatographie liquide couplée à de la spectrométrie de masse en tandem utilisées au Centre hospitalier universitaire de Rennes (Waters Xevo TQ XSTM et Thermo Scientific Q ExactiveTM), cet article présente également le retour d'expérience de biologistes médicaux dans l'amélioration continue des méthodes de dosages des amanitines.

Comparison of Illicit Drug Seizures Products of Natural Origin Using a Molecular Networking Approach.

Drug powder composition analysis is of particular interest in forensic investigations to identify illicit substance content, cutting agents and impurities. Powder profiling is difficult to implement due to multiple analytical methods requirement and remains a challenge for forensic toxicology laboratories. Furthermore, visualization tools allowing seizure products identification appear to be under-used to date. The aim of this study is to present the utility of molecular networking for the composition establishment of natural origin drugs. A powder suspected to contain heroin and three powders suspected to contain cocaine obtained from law enforcement agency seizures were analyzed using untargeted screening by liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS/MS). Molecular networking and metabolite annotation applied to suspected heroin sample allowed rapid confirmation of its illicit content (heroin), the identification of structurally related major impurities (6-monoacetylmorphine, 6-monoacetylcodeine, noscapine, and papaverine), as well as cutting agents (acetaminophen and caffeine). The cocaine powder profiling allowed the comparison of its constituents in a semi-quantitative manner (cocaine, benzoylecgonine, trans/cis-cinnamoylcocaine, trimethoxycocaine, hexanoylecgonine methylester, caffeine, hydroxyzine, levamisole, and phenacetin), bringing additional information for their identification, including geographically sourcing of natural product and their putative place in the supply chain. Although this approach does not replace the profiling techniques used by forensic laboratories, the use of molecular networks provides a visual overview of structurally related constituents which aids the comparison and investigation of seizure powders. Molecular networks offers here an ideal way to depict structurally related and unrelated compounds in these often complex mixtures of chemicals.

New psychoactive substance cocktail in an intensive care intoxication case elucidated by molecular networking.

BACKGROUND: The recreational use of new psychoactive substances (NPS) is increasing worldwide. Among them, the arylcyclohexylamine family including phencyclidine (PCP) and ketamine derivatives is increasing. We report a non-fatal intoxication mainly due to arylcyclohexylamine compounds illustrated by molecular networking (MN). CASE DETAILS: A 37-year-old man with a history of drug abuse was discovered with several bags labeled as research chemicals around him and traces of powder on his nose. He was rehydrated, intubated, and admitted to the intensive care unit (ICU). Urine and drug were analyzed by liquid chromatography-mass spectrometry for NPS identification. Several NPS were quantified in urine: 3-OH-PCP at 12,085 mg/L, 3-MeO-PCP at 1100 mg/L, 2F-DCK at 147 mg/L, N-ethylhexedrone at 165 mg/L and CMC at 48 mg/L. Using a bioinformatic approach, a molecular network was built to confirm the consumption of powders contained in the bags by comparison with patient's urine. DISCUSSION: This case illustrates the interest of MN to (i) perform sample-to-sample comparison, (ii) target quantification methods, and (iii) allow proper management to confirm the relevance of the treatment.

In vivo and in vitro α-amanitin metabolism studies using molecular networking.

Amanitin poisonings are among the most life-threatening mushroom poisonings, and are mainly caused by the genus Amanita. Hepatotoxicity is the hallmark of amanitins, powerful toxins contained in these mushrooms, and can require liver transplant. Among amatoxins, α-amanitin is the most studied. However, the hypothesis of a possible metabolism of amanitins is still controversial in this pathophysiology. Therefore, there is a need of clarification using cutting-edge tools allowing metabolism study. Molecular network has emerged as powerful tool allowing metabolism study through organization and representation of untargeted tandem mass spectrometry (MS/MS) data in a graphical form. The aim of this study is to investigate amanitin metabolism using molecular networking. In vivo (four positive amanitin urine samples) and in vitro (differentiated HepaRG cells supernatant incubated with α-amanitin 2 µM for 24 h) samples were extracted and analyzed by LC-HRMS/MS using a Q Exactive™ Orbitrap mass spectrometer. Using molecular networking on both in vitro and in vivo, we have demonstrated that α-amanitin does not undergo metabolism in human. Thus, we provide solid evidence that a possible production of amanitin metabolites cannot be involved in its toxicity pathways. These findings can help to settle the debate on amanitin metabolism and toxicity.