Cécile Legallais

Bio: Cécile Legallais is an academic researcher from University of Technology of Compiègne. The author has contributed to research in topics: Bioartificial liver device & Medicine. The author has an hindex of 31, co-authored 136 publications receiving 2696 citations. Previous affiliations of Cécile Legallais include Centre national de la recherche scientifique.

Development of a renal microchip for in vitro distal tubule models.

Abstract: Current developments in tissue engineering and microtechnology fields have allowed the proposal of pertinent tools, microchips, to investigate in vitro toxicity. In the framework of the proposed REACH European directive and the 3R recommendations, the purpose of these microtools is to mimic organs in vitro to refine in vitro culture models and to ultimately reduce animal testing. The microchip consists of functional living cell microchambers interconnected by a microfluidic network that allows continuous cell feeding and waste removal controls by fluid microflow. To validate this approach, Madin Darby Canine Kidney (MDCK) cells were cultivated inside a polydimethylsiloxane microchip. To assess the cell proliferation and feeding, the number of inoculated cells varied from 5 to 10 x 10(5) cells/microchip (corresponding roughly to 2.5 to 5 x 10(5) cells/cm2) and from four flow rates 0, 10, 25, and 50 microL/min were tested. Morphological observations have shown successful cell attachment and proliferation inside the microchips. The best flow rate appears to be 10 microL/min with which the cell population was multiplied by about 2.2 +/- 0.1 after 4 days of culture, including 3 days of perfusion (in comparison to 1.7 +/- 0.2 at 25 microL/min). At 10 microL/min flow rate, maximal cell population reached about 2.1 +/- 0.2 x 10(6) (corresponding to 7 +/- 0.7 x 10(7) cells/cm(3)). The viability, assessed by trypan blue and lactate deshydrogenase measurements, was found to be above 90% in all experiments. At 10 microL/min, glucose monitoring indicated a cell consumption of 16 +/- 2 microg/h/10(6) cells, whereas the glutamine metabolism was demonstrated with the production of NH3 by the cells about 0.8 +/- 0.4 micromol/day/10(6) cells. Augmentation of the flow rate appeared to increase the glucose consumption and the NH3 production by about 1.5- to 2-fold, in agreement with the tendencies reported in the literature. As a basic chronic toxicity assessment in the microchips, 5 mM and 10 mM ammonium chloride loadings, supplemented in the culture media, at 0, 10, and 25 micaroL/min flow rates were performed. At 10 microL/min, a reduction of 35% of the growth ratio with 5 mM and of 50% at 10 mM was found, whereas at 25 microL/min, a reduction of 10% with 5 mM and of 30% at 10 mM was obtained. Ammonium chloride contributed to increase the glucose consumption and to reduce the NH3 production. The microchip advantages, high surface/volume ratio, and dynamic loadings, coupled with the concordance between the present and literature results dealing with ammonia/ammonium effects on MDCK illustrate the potential of our microchip for wider in vitro chronic toxicity investigations.

Improvement of HepG2/C3a cell functions in a microfluidic biochip.

Abstract: Current developments in tissue engineering and microtechnology fields allow the use of microfluidic biochip as microtools for in vitro investigations. In the present study, we describe the behavior of HepG2/C3a cells cultivated in a poly(dimethylsiloxane) (PDMS) microfluidic biochip coupled to a perfusion system. Cell culture in the microfluidic biochip for 96 h including 72 h of perfusion provoked a 24 h delay in cell growth compared to plate cultures. Inside the microfluidic biochip, few apoptosis, and necrosis were detected along the culture and 3D cell organization was observed. Regarding the hepatic metabolism, glucose and glutamine consumptions as well as albumin synthesis were maintained. A transcriptomic analysis performed at 96 h of culture using Affymetrix GeneChip demonstrated that 1,025 genes with a fold change above 1.8 were statistically differentially expressed in the microfluidic biochip cultures compared to plate cultures. Among those genes, phase I enzymes involved in the xenobiotic's metabolism such as the cytochromes P450 (CYP) 1A1/2, 2B6, 3A4, 3A5, and 3A7 were up-regulated. The CYP1A1/2 up-regulation was associated with the appearance of CYP1A1/2's activity evidenced by using EROD biotransformation assay. Several phase II enzymes such as sulfotransferases (SULT1A1 and SULT1A2), UDP-glucuronyltransferase (UGT1A1, UGT2B7) and phase III transporters (such as MDR1, MRP2) were also up-regulated. In conclusion, microfluidic biochip could and provide an important insight to exploring the xenobiotic's metabolism. Altogether, these results suggest that this kind of biochip could be considered as a new pertinent tool for predicting cell toxicity and clearance of xenobiotics in vitro.

Biomaterials in Tendon and Skeletal Muscle Tissue Engineering: Current Trends and Challenges

Abstract: Tissue engineering is a promising approach to repair tendon and muscle when natural healing fails. Biohybrid constructs obtained after cells’ seeding and culture in dedicated scaffolds have indeed been considered as relevant tools for mimicking native tissue, leading to a better integration in vivo. They can also be employed to perform advanced in vitro studies to model the cell differentiation or regeneration processes. In this review, we report and analyze the different solutions proposed in literature, for the reconstruction of tendon, muscle, and the myotendinous junction. They classically rely on the three pillars of tissue engineering, i.e., cells, biomaterials and environment (both chemical and physical stimuli). We have chosen to present biomimetic or bioinspired strategies based on understanding of the native tissue structure/functions/properties of the tissue of interest. For each tissue, we sorted the relevant publications according to an increasing degree of complexity in the materials’ shape or manufacture. We present their biological and mechanical performances, observed in vitro and in vivo when available. Although there is no consensus for a gold standard technique to reconstruct these musculo-skeletal tissues, the reader can find different ways to progress in the field and to understand the recent history in the choice of materials, from collagen to polymer-based matrices.

Reconstituting Organ-Level Lung Functions on a Chip

Abstract: Here, we describe a biomimetic microsystem that reconstitutes the critical functional alveolar-capillary interface of the human lung. This bioinspired microdevice reproduces complex integrated organ-level responses to bacteria and inflammatory cytokines introduced into the alveolar space. In nanotoxicology studies, this lung mimic revealed that cyclic mechanical strain accentuates toxic and inflammatory responses of the lung to silica nanoparticles. Mechanical strain also enhances epithelial and endothelial uptake of nanoparticulates and stimulates their transport into the underlying microvascular channel. Similar effects of physiological breathing on nanoparticle absorption are observed in whole mouse lung. Mechanically active "organ-on-a-chip" microdevices that reconstitute tissue-tissue interfaces critical to organ function may therefore expand the capabilities of cell culture models and provide low-cost alternatives to animal and clinical studies for drug screening and toxicology applications.

Microfluidic organs-on-chips

Abstract: Organ-level physiology is recapitulated in vitro by culturing cells in perfused, microfluidic devices.