Dynamic culture of human liver equivalents inside a micro-bioreactor for long-term substance testing : From 23rd European Society for Animal Cell Technology (ESACT) Meeting: Better Cells for Better Health Lille, France. 23-26 June 2013

Published by BioMed Central: Materne, Eva-Maria et al.: Dynamic culture of human liver equivalents inside a micro-bioreactor for longterm substance testing. - In: BMC Proceedings. - ISSN 1753-6561 (online). - 7 (2012), suppl. 6, art. P72. - doi:10.1186/1753-6561-7-S6-P72

A dynamic multi-organ-chip for long-term cultivation and substance testing proven by 3D human liver and skin tissue co-culture

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Current in vitro and animal tests for drug development are failing to emulate the systemic organ complexity of the human body and, therefore, to accurately predict drug toxicity. In this study, we present a multi-organ-chip capable of maintaining 3D tissues derived from cell lines, primary cells and biopsies of various human organs. We designed a multi-organ-chip with co-cultures of human artificial liver microtissues and skin biopsies, each a 1/100 000 of the biomass of their original human organ counterparts, and have successfully proven its long-term performance. The system supports two different culture modes: i) tissue exposed to the fluid flow, or ii) tissue shielded from the underlying fluid flow by standard Transwell® cultures. Crosstalk between the two tissues was observed in 14-day co-cultures exposed to fluid flow. Applying the same culture mode, liver microtissues showed sensitivity at different molecular levels to the toxic substance troglitazone during a 6-day exposure. Finally, an astonishingly stable long-term performance of the Transwell®-based co-cultures could be observed over a 28-day period. This mode facilitates exposure of skin at the air–liquid interface. Thus, we provide here a potential new tool for systemic substance testing.BMBF, 0315569, GO-Bio 3: Multi-Organ-Bioreaktoren für die prädiktive Substanztestung im Chipforma

Chip-based human liver-intestine and liver-skin co-culture : A first step toward systemic repeated dose substance testing in vitro

Systemic repeated dose safety assessment and systemic efficacy evaluation of substances are currently carried out on laboratory animals and in humans due to the lack of predictive alternatives. Relevant international regulations, such as OECD and ICH guidelines, demand long-term testing and oral, dermal, inhalation, and systemic exposure routes for such evaluations. So-called “human-on-a-chip” concepts are aiming to replace respective animals and humans in substance evaluation with miniaturized functional human organisms. The major technical hurdle toward success in this field is the life-like combination of human barrier organ models, such as intestine, lung or skin, with parenchymal organ equivalents, such as liver, at the smallest biologically acceptable scale. Here, we report on a reproducible homeostatic long-term co-culture of human liver equivalents with either a reconstructed human intestinal barrier model or a human skin biopsy applying a microphysiological system. We used a multi-organ chip (MOC) platform, which provides pulsatile fluid flow within physiological ranges at low media-to-tissue ratios. The MOC supports submerse cultivation of an intact intestinal barrier model and an air–liquid interface for the skin model during their co-culture with the liver equivalents respectively at 1/100.000 the scale of their human counterparts in vivo. To increase the degree of organismal emulation, microfluidic channels of the liver–skin co-culture could be successfully covered with human endothelial cells, thus mimicking human vasculature, for the first time. Finally, exposure routes emulating oral and systemic administration in humans have been qualified by applying a repeated dose administration of a model substance – troglitazone – to the chip-based co-cultures.BMBF/0315569/GO-Bio 3: Multi-Organ-Bioreaktoren für die prädiktive Substanztestung im Chipforma

Etude quantitative de la microcirculation hépatique par résonance magnétique et scanographie

Bien qu'au centre des débats depuis plus d'un siècle déjà avec les premiers modèles de foie perfusé, ce n'est que depuis une trentaine d'années avec les travaux de Rappaport que la compréhension de la circulation hépatique a réellement progressé. Il est actuellement bien établi qu'au travers de la structure particulière des sinusoïdes hépatiques, la fonction hépatique est étroitement liée à la perfusion hépatique. Quantifier la perfusion hépatique trouve donc toute sa place dans l'étude du foie sain et pathologique. En plein essor technologique avec l'avènement de l'imagerie rapide volumique et isotropique, la scanographie et l'imagerie par résonance magnétique sont dotées d'une excellente résolution spatiale et temporelle et sont capables de réaliser simultanément une analyse morphologique et fonctionnelle du foie. Cette thèse a développé, validé, et appliqué une méthode non-invasive d'étude de la microcirculation hépatique au moyen de la scanographie et de l'imagerie par résonance magnétique. Elle est basée sur une modélisation mono-compartimentale à deux entrées et l'administration intraveineuse d'agents de contraste extracellulaire et intravasculaire. Ses résultats peuvent être exprimés en terme de perfusion et de perméabilité. Ils ont été validés chez l'animal avec la technique des microsphères selon la méthode de l'échantillonage artériel. La capillarisation et la collagénisation sinusoïdales observées dans la fibrose et la cirrhose hépatiques entraînent des modifications de la perméabilité capillaire dont les répercussions sur les paramètres de la microcirculation hépatique ont été démontrées, résultats corroborant ceux obtenus ex-vivo avec la technique de dilution des indicateurs multiples. En pratique clinique, notre méthode peut également être appliquée à la détection et le suivi des tumeurs hépatiques, l'évaluation du greffon hépatique, mais également dans l'étude de la biodisponibilité de certaines substances chez le sujet sain ou malade. L'analyse fonctionnelle que nous avons développée peut être réalisée dans le même temps qu'une analyse morphologique. Appareillages et traceurs sont facilement accessibles puisque ne différant pas de notre pratique quotidienne. Seul le logiciel de post-traitement doit être implanté. La scanographie et l'imagerie par résonance magnétique ont chacune leurs propres avantages et inconvénients, avec peut-être une petite longueur d'avance pour la scanographie en raison de sa plus grande accessibilité mais qui doit être pondérée par son caractère irradiant et la néphrotoxicité de ses agents de contraste. L'accroissement du nombre d'appareils d'imagerie par résonance magnétique et l'évolution technologique redistribueront sans doute les cartes dans un avenir proche.Thèse de doctorat en sciences médicales (radiologie) (MED 3) -- UCL, 200

Test-positive rate at CT colonography is increased by rectal bleeding and/orunexplained weight loss, unlike other common gastrointestinal symptoms

Purpose: We evaluated the rate of significant colonic and extra-colonic abnormalities at computed tomography colonography (CTC), accordingto symptoms and age. Materials and methods: We retrospectively evaluated 7361 consecutive average-risk subjects (3073 males, average age: 60.3 ± 13.9; range 18–96years) for colorectal cancer (CRC) who underwent CTC. They were divided into three groups according to clinical symptoms: 1343 asymptomaticindividuals (group A), 899 patients with at least one “alarm” symptom for CRC, including rectal bleeding and unexplained weight loss (groupC), and 5119 subjects with other gastrointestinal symptoms (group B). Diagnostic and test-positive rates of CTC were established using opticalcolonoscopy (OC) and/or surgery as reference standard. In addition, clinically significant extra-colonic findings were noted. Results: 903 out of 7361 (12%, 95% confidence interval (CI) 0.11–0.13) subjects had at least one clinically significant colonic finding at CTC. CTCtrue positive fraction and false positive fraction were respectively 637/642 (99.2%, 95%CI 0.98–0.99) and 55/692 (7.95%, 95%CI 0.05–0.09). Thepooled test-positive rate in group C (138/689, 20.0%, 95%CI 0.17–0.23) was significantly higher than in both groups A (79/1343, 5.9%, 95%CI0.04–0.07) and B (420/5329, 7.5%, 95%CI 0.07–0.08) (p < 0.001). Aging and male gender were associated to a higher test positive rate. The rateof clinically significant extra-colonic findings was significantly higher in group C (44/689, 6.4%, 95%CI 0.04–0.08) versus groups A (26/1343,1.9%, 95%CI 0.01–0.02) and B (64/5329, 1.2%, 95%CI 0.01–0.02) (p < 0.001).Conclusion: Both test-positive and significant extra-colonic finding rates at CTC are significantly increased in the presence of “alarm” gastroin-testinal symptoms especially in older patients

Value of multislice helical CT scans and maximum-intensity-projection images to improve detection of ureteral stones at abdominal radiography.

OBJECTIVE: The purpose of this study was to assess the improvement in the detection of ureteral stones on abdominal radiographs when the stones were viewed on multislice helical CT scans and maximum-intensity-projection (MIP) images. SUBJECTS AND METHODS: The study included 72 patients with renal colic who underwent abdominal radiography and multislice helical CT. For each patient, a frontal MIP image was generated, and the stone, when present, was marked with a cross on the transverse CT scan. The cross appeared automatically on the corresponding MIP image. The CT examination was used as the standard of reference. The presence and location of ureteral stones on the abdominal radiographs were assessed during three interpretation sessions. In the first session, the abdominal radiographs were viewed alone. In the second, they were viewed with the transverse CT scans. In the third, the abdominal radiographs were viewed with the CT scans and the MIP images. RESULTS: Ureteral stones were present in 58 patients. The percentage of stones detected on the abdominal radiographs was 45% when the radiographs were viewed alone, 66% when they were viewed with the CT scans (p = 0.002 vs radiographs alone), and 78% when viewed with the CT scans and MIP images (p = 0.016 vs radiographs with CT scans). CONCLUSION: The sensitivity of stone detection on abdominal radiographs was greatest when the interpreters viewed the radiographs in conjunction with the CT scans and MIP images