Fish-gut-on-chip: development of a microfluidic bioreactor to study the role of the fish intestinein vitro

Abstract

In this study we present the first fish-gut-on-chip model. This model is based on the reconstruction of the intestinal barrier by culturing two intestinal cell lines from rainbow trout, namely epithelial RTgutGC and fibroblastic RTgutF, in an artificial microenvironment. For a realistic mimicry of the interface between the intestinal lumen and the interior of the organism we i) developed ultrathin and highly porous silicon nitride membranes that serve as basement membrane analogues and provide a culture interface for the fish cells;ii) constructed a unique micro-well plate-based microfluidic bioreactor that enables parallelization of experiments and creates realistic fluid flow exposure scenarios for the cells; iii) integrated electrodes in the reactor for non-invasive impedance sensing of cellular well-being. In a first approach, we used this reactor to investigate the response of epithelial fish cells to in vivo-like shear stress rates of 0.002-0.06 dyne per cm 2 , resulting from fluid flow within the intestinal lumen. Moreover, we investigated the interplay of epithelial and fibroblast cells under optimal flow conditions to carefully evaluate the benefits and drawbacks of the more complex reconstruction of the intestinal architecture. With our fish-gut-on-chip model we open up new strategies for a better understanding of basic fish physiology, for the refinement of fish feed in aquaculture and for predicting chemical uptake and bioaccumulation in fish for environmental risk assessment. The basic principles of our reactor prototype, including the use of ultrathin membranes, an open microfluidic circuit for perfusion and the micro-well plate-based format for simplified handling and avoidance of air-bubbles, will as well be of great value for other barrier-on-chip models.

Temporal changes in the gut microbiota in farmed Atlantic cod (Gadus morhua) outweigh the response to diet supplementation with macroalgae

“…It has previously been shown in other fish, that the gut microbiota is highly malleable during the first-feeding and initial lifecycle period (e.g. rainbow trout [107]), and stabilises over time as we observed. The microbial associations observed need to be further characterised.…”

New Stable Cell Lines Derived from the Proximal and Distal Intestine of Rainbow Trout (Oncorhynchus mykiss) Retain Several Properties Observed In Vivo

“…We extended the epithelial characterization of all these lines, showing the expression of E-cadherin and Claudin, two molecules that interact with zonula occludens 1 for maintenance of the intestinal epithelium barrier and signal transduction between adjacent cells [ 28 , 29 ]. RTgutGC cells translate the expression of epithelial barrier genes into the formation of a functional barrier, as indicated by increasing TEER values measured at regular intervals up to 21 days after seeding [ 18 , 23 , 30 , 31 , 32 ]. Both RTpi-MI and RTdi-MI cell lines developed similar TEER values between 3 and 21 days of culture, which was close to the baseline resistance (50–400 Ω cm 2 ) measured in in vivo studies [ 33 , 34 ].…”

Microphysiological Systems: gold standard approach towards in vitro biomimetics and its potential to drive forward the fisheries sector to the next level

“…Another microfluidic based lab on a chip technology was validated in zebrafish embryos for automation of toxicity test [60] . Very recently, the first of its kind fish-gut-on-a-chip model was proposed in rainbow trout for a better understanding of basic fish physiology, for the refinement of fish feed in aquaculture and for predicting chemical uptake and bioaccumulation in fish for environmental risk assessment [61] . Apart from fishes, gelatin cantilever substrate based MPS has been fabricated very recently using mussels in order to measure cardiac contractility [62] .…”