Quantifying the transport of biologics across intestinal barrier models in real-time by fluorescent imaging

Abstract

Unsuccessful clinical translation of orally delivered biological drugs remains a challenge in pharmaceutical development and has been linked to insufficient mechanistic understanding of intestinal drug transport. Live cell imaging could provide such mechanistic insights by directly tracking drug transport across intestinal barriers at subcellular resolution, however traditional intestinal in vitro models are not compatible with the necessary live cell imaging modalities. Here, we employed a novel microfluidic platform to develop an in vitro intestinal epithelial barrier compatible with advanced widefield- and confocal microscopy. We established a quantitative, multiplexed and high-temporal resolution imaging assay for investigating the cellular uptake and cross-barrier transport of biologics while simultaneously monitoring barrier integrity. As a proof-of-principle, we use the generic model to monitor the transport of co-administrated cell penetrating peptide (TAT) and insulin. We show that while TAT displayed a concentration dependent difference in its transport mechanism and efficiency, insulin displayed cellular internalization, but was restricted from transport across the barrier. This illustrates how such a sophisticated imaging based barrier model can facilitate mechanistic studies of drug transport across intestinal barriers and aid in vivo and clinical translation in drug development.

An Integrated and Modular Compartmentalized Microfluidic System with Tunable Electrospun Porous Membranes for Epithelialized Organs-on-a-Chip

“…Drug molecules may transport through the intestinal epithelium via different pathways, depending on their size and hydrophilicity. Large molecules such as dextran (40 kDa) and metformin (165 kDa) may not permeate through the paracellular route due to their size and hydrophilic nature. , At physiological pHs, metformin is a hydrophilic cation that is highly soluble but poorly permeable in the intestine. , The oral absorption of metformin in humans is dose-dependent and saturable, indicating the involvement of a complex transport-mediated mechanism . This in vitro model can be aptly used to study the different permeation pathways of small and macromolecules through the intestinal epithelium and to identify methods for enhancing the absorption of drug candidates.…”

“…Large molecules such as dextran (40 kDa) and metformin (165 kDa) may not permeate through the paracellular route due to their size and hydrophilic nature. 59,60 At physiological pHs, metformin is a hydrophilic cation that is highly soluble but poorly permeable in the intestine. 61,62 The oral absorption of metformin in humans is dose-dependent and saturable, indicating the involvement of a complex transportmediated mechanism.…”

Fluid flow to mimic organ function in 3D in vitro models

“… 178 And as in the mentioned study, other works have shown the integration of BVs with tissues like mammary ducts to reveal their close interaction. 188 Perfused Caco-2 intestine tubes were proven to work as models for drug discovery and transport across intestinal barriers 182,189 or to analyze radical oxygen species (ROS) levels and cell viability. 177 On another note, angiogenesis models originating from rocker-perfused vessels 177,190 have been used to irrigate complex biological systems, such as in vitro models of respiration 191 or organoids, 9,192,193 though these models are more commonly perfused with pump-based systems, due to the long-term maturation times required to maintain their physiology.…”