Pharmacologie & Transplantation

Understanding the emergence of human notochordal cells (NC) is essential for the development of regenerative approaches. We present a comprehensive investigation into the specification and generation of bona fide NC using a straightforward pluripotent stem cell (PSC)-based system benchmarked with human fetal notochord. By integrating in vitro and in vivo transcriptomic data at single-cell resolution, we establish an extended molecular signature and overcome the limitations associated with studying human notochordal lineage at early developmental stages. We show that TGF-β inhibition enhances the yield and homogeneity of notochordal lineage commitment in vitro . Furthermore, this study characterizes regulators of cell-fate decision and matrisome enriched in the notochordal niche. Importantly, we identify specific cell-surface markers opening avenues for differentiation refinement, NC purification, and functional studies. Altogether, this study provides a human notochord transcriptomic reference that will serve as a resource for notochord identification in human systems, diseased-tissues modeling, and facilitating future biomedical research.

BACKGROUND: Ischemia-related injury during the preimplantation period impacts kidney graft outcome. Evaluating these lesions by a noninvasive approach before transplantation could help us to understand graft injury mechanisms and identify potential biomarkers predictive of graft outcomes. This study aims to determine the metabolomic content of graft perfusion fluids and its dependence on preservation time and to explore whether tubular transporters are possibly involved in metabolomics variations. METHODS: Kidneys were stored on hypothermic perfusion machines. We evaluated the metabolomic profiles of perfusion fluids (n = 35) using liquid chromatography coupled with tandem mass spectrometry and studied the transcriptional expression of tubular transporters on preimplantation biopsies (n = 26), both collected at the end of graft perfusion. We used univariate and multivariate analyses to assess the impact of perfusion time on these parameters and their relationship with graft outcome. RESULTS: Seventy-two metabolites were found in preservation fluids at the end of perfusion, of which 40% were already present in the native conservation solution. We observed an increase of 23 metabolites with a longer perfusion time and a decrease of 8. The predictive model for time-dependent variation of metabolomics content showed good performance (R 2 = 76%, Q 2 = 54%, accuracy = 41%, and permutation test significant). Perfusion time did not affect the mRNA expression of transporters. We found no correlation between metabolomics and transporters expression. Neither the metabolomics content nor transporter expression was predictive of graft outcome. CONCLUSIONS: Our results call for further studies, focusing on both intra- and extratissue metabolome, to investigate whether transporter alterations can explain the variations observed in the preimplantation period.

The toxicity of tacrolimus metabolites and their potential pharmacodynamic (PD) interactions with tacrolimus might respectively explain the surprising combination of higher toxicity and lower efficacy of tacrolimus despite normal blood concentrations, described in extensive metabolizers. To evaluate such interactions, we produced tacrolimus metabolites in vitro and characterized them by high resolution mass spectrometry (HRMS, for all) and nuclear magnetic resonance (NMR, for the most abundant, M-I). We quantified tacrolimus metabolites and checked their structure in patient whole blood and peripheral blood mononuclear cells (PBMC). We explored the interactions of M-I with tacrolimus in silico , in vitro and ex vivo . In vitro metabolization produced isoforms of tacrolimus and of its metabolites M-I and M-III, whose HRMS fragmentation suggested an open-ring structure. M-I and M-III open-ring isomers were also observed in patient blood. By contrast, NMR could not detect these open-ring forms. Transplant patients expressing CYP3A5 exhibited higher M-I/TAC ratios in blood and PBMC than non-expressers. Molecular Dynamics simulations showed that: all possible tacrolimus metabolites and isomers bind FKPB12; and the hypothetical open-ring structures induce looser binding between FKBP12 and calcineurins, leading to lower CN inhibition. In vitro , tacrolimus bound FKPB12 with more affinity than purified M-I, and the pool of tacrolimus metabolites and purified M-I had only weak inhibitory activity on IL2 secretion and not at all on NFAT nuclear translocation. M-I showed no competitive effect with tacrolimus on either test. Finally, M-I or the metabolite pool did not significantly interact with tacrolimus MLR suppression, thus eliminating a pharmacodynamic interaction. • HRMS, but not NMR, identified isomers of tacrolimus and metabolites with pyranyl-ring opening. • In silico , all tacrolimus derivatives bound FKBP12 with similar affinity. • However, the M-I metabolite had lower calcineurin inhibition potency than tacrolimus. • M-I or a tacrolimus metabolite pool hardly inhibited NFAT nuclear translocation and IL2 secretion and had not effect on one-way lymphocyte reaction. • Tacrolimus metabolites have probably no competitive or antagonistic effects with tacrolimus.

BACKGROUND: The impact of prior exposure to systemic corticosteroids on COVID-19 severity in patients hospitalized for a SARS-CoV-2 pneumonia is not known. The present study was designed to answer to this question. METHODS: The population study was the Covid-Clinic-Toul cohort which records data about all hospitalized patients with a positive reverse transcriptase polymerase chain reaction for a SARS-CoV-2 infection at Toulouse University hospital, France. Exposure to systemic corticosteroids was assessed at hospital admission. A propensity score (PS) according to corticosteroid exposure was calculated including comorbidities, clinical, radiological and biological variables that impact COVID-19 severity. The primary outcome was composite, including admission to intensive care unit, need of mechanical ventilation and death occurring during the 14 days after hospital admission. Logistic regression models adjusted for the PS (overlap weighting) provided odds ratios (ORs) and their 95% confidence intervals (95% CIs). RESULTS: Overall, 253 patients were included in the study. Median age was 64 years, 140 patients (59.6%) were men and 218 (86.2%) had at least one comorbidity. Seventeen patients (6.7%) were exposed to corticosteroids before hospital admission. Chronic inflammatory disease (n = 8) was the most frequent indication. One hundred and twenty patients (47.4%) met the composite outcome. In the crude model, the OR of previous exposure to systemic corticosteroids was 1.64; 95% CI: 0.60-4.44. In the adjusted model, it was 1.09 (95% CI: 0.65-1.83). CONCLUSION: Overall, this study provide some evidences for an absence of an increased risk of unfavorable outcome with previous exposure to corticosteroids in the general setting of patients hospitalized for COVID-19.

Abstract Early and sensitive biomarkers of liver dysfunction and drug-induced liver injury (DILI) are still needed, both for patient care and drug development. We developed the Serum Enhanced Binding (SEB) test to reveal post-transcriptional modifications (PTMs) of human serum albumin resulting from hepatocyte dysfunctions and further evaluated its performance in an animal model. The SEB test consists in spiking serum ex-vivo with ligands having specific binding sites related to the most relevant albumin PTMs and measuring their unbound fraction. To explore the hypothesis that albumin PTMs occur early during liver injury and can also be detected by the SEB test, we induced hepatotoxicity in male albino Wistar rats by administering high daily doses of ethanol and CCl 4 over several days. Blood was collected for characterization and quantification of albumin isoforms by high-resolution mass spectrometry, for classical biochemical analyses as well as to apply the SEB test. In the exposed rats, the appearance of albumin isoforms paralleled the positivity of the SEB test ligands and histological injuries. These were observed as early as D3 in the Ethanol and CCl 4 groups, whereas the classical liver tests (ALT, AST, PAL) significantly increased only at D7. The behavior of several ligands was supported by structural and molecular simulation analysis. The SEB test and albumin isoforms revealed hepatocyte damage early, before the current biochemical biomarkers. The SEB test should be easier to implement in the clinics than albumin isoform profiling.

Cytomegalovirus (CMV) infection poses significant challenges in pediatric transplant recipients. Ganciclovir and its prodrug valganciclovir are primary treatments because of their potent antiviral effects. Balancing efficacy and toxicity is particularly critical in children. This study aimed to develop a pharmacokinetic/pharmacodynamic (PK/PD) model for (val)ganciclovir and assess the relationship between area under the concentration–time curve (AUC) and CMV viral loads via Monte Carlo simulations. We conducted a retrospective analysis including 184 viral load samples from 36 transplanted children treated with ganciclovir/valganciclovir. We developed a population pharmacodynamic model using Monolix and performed Monte Carlo simulations to assess viral load decline with varying AUCs. Internal validation was performed using goodness-of-fit plots and bootstraps. We used a viral turnover model with stimulated degradation to model the pharmacodynamic data. Model validation showed no bias or misspecification. Simulations indicated that maintaining an AUC 0-24 ≥ 40 mg·h/L achieved an 85.4% probability of undetectable viral load after 28 days of therapy. An AUC 0-24 > 30 mg·h/L provided 80.9% probability of reducing viral loads by − 1 log after 2 weeks. AUC 0-24 values > 60 mg·h/L offered minimal incremental benefits. The pharmacodynamic model accurately predicted observed data. Simulations indicated that maintaining a ganciclovir plasma AUC 0-24 around 40–60 mg·h/L maximized antiviral efficacy. An AUC 0-24 > 60 mg·h/L might increase the risk of adverse events without providing additional efficacy.

ABSTRACT: The concept of pharmacokinetic (PK) boosting of calcineurin inhibitors (CNI) emerged after the FDA approval of cyclosporine-A. Several studies followed, and the proof of concept was well established by the late 1990s. This also continued for the next blockbuster immunosuppressant, tacrolimus. The driver for such research was an endeavor to save costs, as both drugs were expensive due to patent protection. Two CYP inhibitors, ketoconazole and diltiazem, have been extensively studied in this context and continue to be prescribed off-label along with the CNI. It has been observed that using ketoconazole reduces the dose requirement of tacrolimus by about 50% and 30% with diltiazem, which is in conformity with their pharmacological actions. Off-label co-prescription of these drugs with CNI is often encountered in low and middle-income countries. The foremost reason cited is economic. This article collates the evidence from the clinical studies that evaluate the PK-boosting effects of CNI and also reviews the gaps in the current evidence base. The current knowledge prevents the transplant community from making meaningful inferences about the risks and benefits of such strategies. Although the PK-boosting strategy can lead to serious adverse events, emerging evidence suggests that it may be advantageous for individuals with high CNI dose requirements. Hence, PK boosting may be an unmet need in the therapeutics of CNI. Nevertheless, there are several unanswered questions surrounding such use, and therefore, this merits testing in well-designed clinical studies. Moreover, drugs with better safer profiles and a history of successful PK boosting may be considered for evaluation with CNI.

ABSTRACT: In transplantation, the association of tacrolimus exposure with efficacy is better known than with adverse effects. The ExpoTac study explored the relationships between tacrolimus exposure and adverse events (AEs) in kidney transplant patients who benefited from at least 3 measurements of tacrolimus area under the curve (AUC) within 2 years of transplantation. The relationships between tacrolimus AUC, trough concentration C 0 , peak concentration C max , and AEs were explored using univariate analysis and Cox models in 386 patients (1281 sets of exposure biomarkers). Headaches and renal impairment potentially induced by tacrolimus were associated with significantly lower mean dose-standardized exposure biomarkers and a higher proportion of C max values above the median. Patients with tremor displayed significantly higher mean AUC 0-24 (343 ± 79 versus 308 ± 63 hours·mcg/L, P = 0.041). Cox analysis revealed a significant association between (1) the time to the first headache report and mean C max , mean AUC 0-24 , and the proportion of C max values above the median (hazard ratios [95% confidence interval] = 0.237 [0.007-0.538]; 7.499 [1.508-29.713]; 5.055 [1.577-17.137]) and (2) the time to first renal impairment report and the proportion of C 0 values above the median (0.401 [0.098-0.681]). Refining AUC, C max , and C 0 upper limits would help to refine tacrolimus therapeutic ranges and limit the risks of AEs after kidney transplantation.

Amyloidosis is a rare disease, corresponding to a deposition of proteins in various tissues. Amyloid light-chain (AL) amyloidosis can involve the liver in 17% to 45% of patients. Diagnosis of liver disease is based on specific criteria, coupling alkaline phosphatases and hepatomegaly. Liver stiffness is altered in cases of heart involvement, and overall, in cases of liver involvement. Liver biopsy is generally avoided due to an important bleeding risk. Treatment is essentially based on stem cell transplantation and chemotherapy, with large progress during the last decade. Liver involvement recovery is generally diagnosed with a reduction in alkaline phosphatases and in liver size.

Pesticide exposure gradients between occupational, para-occupational, and general populations remain poorly characterized in North African agricultural contexts. This study evaluates urinary pesticide levels among farmers, indirectly exposed individuals, and a control group in Morocco's Fez-Meknes region. A cross-sectional survey measured pesticide concentrations using LC-MS/MS in urine samples collected from 154 adults residing in both rural and urban areas. A questionnaire was used to gather information from participants regarding factors that may elevate the risk of pesticide exposure. The results revealed that farmers exhibited the highest concentrations of pesticides in their urine, including compounds classified as Ia/Ib by the World Health Organization. Indirectly exposed individuals showed moderate levels of contamination, with notable detections such as dichlofluanid (22.13 µg/L), while the control group had residual traces of neonicotinoids, notably imidacloprid (2.05 µg/L). Multivariate analyses revealed several sociodemographic factors significantly associated with increased pesticide exposure. The main risk factors identified included low education, residence in an agricultural area, and the consumption of untreated water (wells/rivers). Conversely, wearing personal protective equipment was associated with reduced urinary concentrations. This study highlights intense occupational exposure among farmers, secondary environmental contamination among residents living near treated areas, and the widespread dispersion of pesticide residues into urban areas.

Chronic liver disease (CLD) affects millions worldwide, yet accurately staging its progression without liver biopsy remains a major clinical challenge. Human serum albumin (HSA), the most abundant blood protein synthesized exclusively by the liver, undergoes measurable structural modifications as liver disease advances, making it a potential molecular marker of disease severity. Using high-resolution liquid chromatography-mass spectrometry (LC-HR-MS), we quantified native HSA and nine modified isoforms in plasma from 172 CLD patients spanning all fibrosis stages and 82 healthy controls. Native HSA declined markedly with disease severity, reaching 4.1-4.2 g/L in decompensated cirrhosis versus 12.2 g/L in controls. Modified isoforms showed stage-specific patterns, and their ratios to native HSA amplified the diagnostic signal for advanced disease. A machine learning classifier trained on the full albumin spectral profile achieved substantial agreement with standard staging, and demonstrated higher accuracy than FIB-4 index (81.5% vs. 59.3% accuracy). Within the study cohort, these results were reproduced on two independent instruments from different manufacturers (McNemar p = 0.149), confirming the reproducibility across different platforms of the albumin signature. These findings establish HSA spectral profiling as a promising non-invasive staging tool for CLD, with cross-platform reproducibility supporting its potential for translation to multicenter clinical practice.

BACKGROUND: Maribavir is currently administered at a dose of 400 mg twice daily (q12h) for the treatment of cytomegalovirus (CMV) infections in transplant recipients. However, virological failure rates of up to 40% have been reported in clinical practice, with potentially severe consequences and the selection of mutant strains. OBJECTIVES: This study aims to evaluate, in silico, the pharmacokinetic (PK) and pharmacodynamic (PD) interest of alternative maribavir dosing regimens using population pharmacokinetic (POPPK) modelling and Monte Carlo simulations. METHODS: A published two-compartment POPPK model with first-order absorption and an absorption lag time was implemented. Monte Carlo simulations (n = 10 000 virtual PK profiles) were performed for maribavir regimens of 400, 600, and 800 mg administered q12h and every 8 h (q8h). PK metrics, including trough concentration (C0) and area under the concentration-time curve (AUC), as well as probability of target attainment (PTA), were compared across regimens at steady state. RESULTS: The standard 400 mg q12h regimen resulted in the lowest PTA, falling below 90% for a pharmacologically active inhibitory concentration 50 of 2 mg/L. In contrast, q8h regimens substantially improved PTA across targets and were associated with reduced interindividual variability in C0. CONCLUSIONS: Increasing dosing frequency to a three-times-daily regimen improved PK/PD target attainment compared with the standard q12h regimen. These findings support the need for prospective clinical and pharmacoeconomic studies to assess the benefit-risk balance of alternative maribavir dosing strategies.

En 2024, le groupe de travail « Suivi thérapeutique pharmacologique et personnalisation des traitements de la Société française de pharmacologie et de thérapeutique » a élaboré un livre blanc dont l’objectif est de présenter l’état des lieux de la sous-discipline de la pharmacologie biologique, de décrire les compétences attendues pour exercer le métier de pharmacologue biologiste, de définir le périmètre de l’activité professionnelle, d’identifier les forces et les points d’amélioration actuels de la sous-discipline dans l’objectif final de proposer les évolutions du métier de pharmacologue biologiste. Ce document se compose de plusieurs parties : un préambule visant à rappeler le panorama de la pharmacologie biologique en France ; un état des lieux rappelant ce qu’est un pharmacologue biologiste, ses missions, les forces et faiblesses de la profession et les pré-requis en termes de formation ; un référentiel de compétences du pharmacologue biologiste et enfin les perspectives et nouvelles missions du pharmacologue biologiste. Ce document a pour vocation de servir de référentiel, d’aider à définir la profession de pharmacologue biologiste et de structurer la discipline afin de pouvoir la faire évoluer vers une profession d’interface entre biologie et clinique. In 2024, the therapeutic drug monitoring and treatment personalization working group of the Société française de pharmacologie et de thérapeutique (French Society of Pharmacology and Therapeutics) drew up a white paper, the aim of which is to present the current state of the biological pharmacology discipline, describe the skills required to exercise the profession, define the scope of professional activity, identify the discipline's current strengths and areas for improvement, with the ultimate aim of proposing changes to the profession of biological pharmacologist. This document is divided into several parts: a preamble outlining the panorama of biological pharmacology in France; a review of the current situation, outlining what a pharmacological biologist is, his or her missions, the strengths and weaknesses of the profession, and the prerequisites in terms of training; a reference framework of competencies for the pharmacological biologist; and, finally, the prospects and new missions of the pharmacological biologist. The purpose of this document is to serve as a term of reference, to help define the profession of pharmacological biologist, and to structure the discipline so that it can evolve into a profession at the interface between biology and the clinic.

Synthetic data generation has emerged as a promising avenue for preserving the privacy of sensitive information, such as medical records, while enabling meaningful data analysis. Yet, the landscape of available techniques is highly fragmented: numerous methods have been proposed, each excelling under specific conditions, and their evaluation is often inconsistent across studies. Fidelity to the original data is frequently prioritized, whereas privacy preservation receives comparatively less attention. In this work, we introduce a versatile ensemble framework; a super learner for synthetic data generation; that adaptively selects and combines methods based on the characteristics of the target dataset. We demonstrate this approach on medium-sized datasets (hundreds of samples), addressing challenges in sharing small biomedical datasets. We systematically assess the influence of different fidelity metrics, including the Energy distance and the Wasserstein distance, on the quality of generated data. Experimental results demonstrate that our approach consistently matches or outperforms the strongest individual method in terms of utility, while delivering enhanced privacy protection.

Quotidiennement, dans le milieu hospitalier, de nombreux médicaments et toxiques sont dosés en urgence par les laboratoires de pharmacologie-toxicologie. Les méthodes utilisées dans ces cas-là sont en majorité des méthodes d’immunochimie ou de chromatographie.Si elles sont rapides, les méthodes immunochimiques se contentent souvent de recherche par famille (benzodiazépines, antidépresseurs, opiacés...) et peuvent manquer à la fois de spécificité et de sensibilité. Pour étendre le panel des molécules recherchées H24 7/7j, certains laboratoires utilisent des approches de chromatographie liquide ou gazeuse, couplée le plus souvent à la spectrométrie de masse. Ces approches requièrent toutefois une préparation parfois complexe des échantillons et ne permettent habituellement pas de rendre un résultat (qualitatif ou quantitatif) en moins de 1 à 2 heures.Les travaux menés visent au développement d’un panel dit « de première ligne » adaptées à un laboratoire d’urgence de pharmacologie-toxicologie, basé sur un couplage PESI- MS/MS.La source PESI (Probe ElectroSpray Ionization) est une méthode d’ionisation, à pression atmosphérique, comprenant une source de type electrospray sous forme d’une fine aiguille mobile permettant un prélèvement direct d’un échantillon dans une matrice biologique.Plusieurs méthodes ont été développées et validées (recherche et dosage des stupéfiants dans la salive, dosage de la metformine plasmatique, du paracétamol et des benzodiazépines sériques…) en combinant la source PESI à des spectromètres de masse de basse et de haute résolution. Certaines sont basées sur une quantification par dilution isotopique permettant de diminuer le temps total d’analyse tout en conservant la fiabilité du résultat.Après une préparation minimaliste des échantillons, ces outils permettent un dosage en quelques dizaines de secondes, tout en bénéficiant de la sensibilité et de la spécificité de la spectrométrie de masse. Ils possèdent ainsi de nombreuses qualités pour faire partie de l’arsenal d’un laboratoire de pharmacologie-toxicologie devant réaliser des analyses en urgence.

L’analyse toxicologique s’applique à un très grand nombre de composés et à un très grand nombre de contextes. Lorsque l’analyse a pour but une recherche large de composés, sans a priori quant à la nature de ceux-ci, on parle de criblage toxicologique, c’est-à-dire un outil analytique dont on attend qu’il puisse détecter et identifier tous les médicaments ou toxiques potentiellement présents. Les objectifs de nos travaux étaient de développer des méthodes de criblage pour la détection et ou la quantification de composés d’intérêt avec un spectromètre de masse de haute résolution de type quadripolaire à temps de vol (QTOF) (LCMS-9030, Shimadzu®), couplé à de la chromatographie liquide. Plus largement, la question posée était celle de l’utilisation des systèmes de haute résolution, de leurs avantages théoriques à leurs applications pratiques. Après avoir construit une bibliothèque spectrale de plusieurs centaines de composés en masse exacte, nous avons donc développé plusieurs méthodes de criblage faisant appel à différents modes d’acquisition ciblés et non ciblés (HR-MSMS, HR-DIA et HR-DDA) que nous avons appliqués à différents contextes de toxicologie clinique, médico-légale et environnementale. Le principal axe de nos travaux fut la comparaison des performances entre une approche QTOF et les approches par spectrométrie de masse de basse résolution.

L’acide mycophénolique (MPA), une molécule importante des protocoles d’immunosuppression en transplantation et pour le traitement de certaines maladies auto-immunes, est fréquemment associée à de nombreux effets indésirables gastro-intestinaux qui se manifestent chez plus de 30 % des patients. La présence de ces troubles gastro-intestinaux altère la qualité de vie des patients et augmente le risque de rejet de greffe. Mon projet de thèse a porté sur la compréhension des mécanismes sous-jacents à cette toxicité, jusqu’alors non-élucidés, ainsi que l’évaluation préclinique d’une stratégie thérapeutique pour prévenir cette entéropathie. Il en ressort que le MPA est capable de perturber l’équilibre de la barrière épithéliale intestinale, en particulier lors de l’exposition à de fortes concentrations. Cet effet sur la barrière intestinale passerait par (i) une augmentation du passage paracellulaire, (ii) une altération des processus cellulaires participant au renouvellement de la barrière épithéliale, et (iii) une perturbation de l’homéostasie cellulaire par la modification de certaines voies métaboliques. De fortes concentrations digestives de MPA sont générées in vivo par l’activité enzymatique de la β-glucuronidase bactérienne, à partir de l’hydrolyse de son métabolite hépatique glucuronidé, le MPAG, qui est excrété dans la bile puis libéré dans le tube digestif. Ainsi, nous avons évalué le potentiel de l’inhibition de la β-glucuronidase bactérienne dans un modèle murin d’entéropathie induite par le MPA. L’inhibition sélective de cette enzyme bactérienne par l’amoxapine, décrite pour cette propriété dans la littérature, a significativement prévenu les lésions associées au MPA sur la barrière intestinale. L’amoxapine a efficacement bloqué l'hydrolyse du MPAG et a diminué l'exposition digestive au MPA. Cette étude démontre donc que l'accumulation digestive du MPA est impliquée dans la physiopathologie des effets indésirables gastro-intestinaux et fournit une preuve de concept du potentiel thérapeutique des inhibiteurs de la β-glucuronidase bactérienne dans l'entéropathie induite par le MPA.

Abstract Deciphering the sources of variability in drug responses requires to understand the processes modulating drug pharmacokinetics. However, pharmacological research suffers from poor reproducibility across clinical, animal, and experimental models. Predictivity can be improved by using Organs-on-Chips, which are more physiological, human-oriented, micro-engineered devices that include microfluidics. OoC are particularly relevant at the fundamental and preclinical stages of drug development by providing more accurate assessment of key pharmacokinetic events. We have developed a proximal tubule-on-a-chip model combining commercial microfluidic and chip technologies. Using the RPTEC/TERT1 cell line, we set up a dual-flow system with antiparallel flows to mimic the dynamics of blood and urine. We assessed transporters mRNA expression using RT-qPCR, cellular polarization and protein expression via immunofluorescence and confocal microscopy, and monitored the transcellular transport of a list of prototypic xenobiotics by determining their efflux ratios with LC-MS/MS. Our results show that flow exposure significantly modulate mRNA expression of drug membrane transporters compared to static conditions. Dynamic conditions also enhance cell polarization, as evidenced by preferential basal and apical expressions of Na+/K+-ATPase, P-gp, OCT2, and MATE1, as well as the cellular secretory profile. We demonstrated unidirectional transcellular transport of a cationic substrate (metformin) with a higher efflux than influx ratio, inhibited with a specific OCT2 inhibitor, thus confirming the relevance of our proximal tubule- on-a-chip set up for cation transport investigations. Our proximal tubule-on-a-chip can also be used to explore the interactions between transporters, xenobiotics, and endogenous metabolites, possibly involved in the variability of individual drug responses. This study provides additional evidence that OoC can bridge the gaps between systemic and local pharmacokinetics, i.e., drug concentration close to its target, at the fundamental and preclinical stages. Highlights Cell exposure to flow shear stress modulate mRNA drug membrane transporters and cell polarization of proximal tubule Proximal tubule-on-chip relying on RPTEC/TERT1 cell line is a suitable platform for assessing transcellular cationic transport OCT2 and MATE are involved in potential drug-endogenous metabolite interactions Cell exposure to xenobiotics and endogenous metabolites modulate the drug transporters expression. Graphical Abstract Data Statement Original microscopy pictures, raw data for metabolomics and other data are available upon reasonable request.

Abstract Background: Early and sensitive biomarkers of liver dysfunction and drug-induced liver injury (DILI) are still needed, both for patient care and drug development. Methods: We developed the Serum Enhanced Binding (SEB) test to reveal post-transcriptional modifications (PTMs) of human serum albumin resulting from hepatocyte dysfunctions and further evaluated its performance in an animal model. The SEB test consists in spiking serum ex-vivo with ligands having specific binding sites related to the most relevant albumin PTMs and measuring their unbound fraction. To explore the hypothesis that albumin PTMs occur early during liver injury and can also be detected by the SEB test, we induced hepatotoxicity in male albino Wistar rats by administering high daily doses of ethanol and CCl4 over several days. Blood was collected for characterization and quantification of albumin isoforms by high-resolution mass spectrometry, for classical biochemical analyses as well as to apply SEB test. Results: In the exposed rats, the appearance of albumin isoforms paralleled the positivity of the SEB test ligands and histological injuries. These were observed as early as D3 in the Ethanol and CCl4 groups, whereas the classical liver tests (ALT, AST, PAL) significantly increased only at D7. The behavior of several ligands were supported by structural and molecular simulation analysis. Conclusion: The SEB test and albumin isoforms revealed hepatocyte damage early, before the current biochemical biomarkers. The SEB test should be easier to implement in the clinics than albumin isoform profiling.

We have conducted two studies on the assessment of exposure to two compounds in tobacco smoke: carbon monoxide and cadmiumIn the first study, we have shown that there was a difference in placental Cd concentration between control FEF (+) versus FEF-CO no quit p<0.0004) and a significant difference between control FEF (+) versus FEF-CO quit p<0.0150.We also showed that there was a significant difference in birth weights between the pregnant smokers and non-smokers groups (p<0.0077). We showed that there was a correlation between the level of exhaled CO and the number of cigarettes at inclusion (p< 0.0174; p< 0.0044 respectively). The second study: The risk of IUGR compared to non-smokers was OR: 2.3 (1.18 - 4.30) p= 0.014 for patients who quit smoking in the 3rd trimester, OR : 2.5 (2.03-3.12) p< 0.001 for women who smoked throughout pregnancy. Active or passive smoking during pregnancy is associated with an increased risk of intrauterine growth retardation and low birth weight during pregnancy. Early cessation reduces the risk of intrauterine growth restriction or low birth weight. Passive smoking has a deleterious impact on fetal development intermediate to that of active smoking.