Hypoxia-enhanced Blood-Brain Barrier Chip recapitulates human barrier function and shuttling of drugs and antibodies

Abstract

The high selectivity of the human blood-brain barrier (BBB) restricts delivery of many pharmaceuticals and therapeutic antibodies to the central nervous system. Here, we describe an in vitro microfluidic organ-on-a-chip BBB model lined by induced pluripotent stem cellderived human brain microvascular endothelium interfaced with primary human brain astrocytes and pericytes that recapitulates the high level of barrier function of the in vivo human BBB for at least one week in culture. The endothelium expresses high levels of tight junction proteins and functional efflux pumps, and it displays selective transcytosis of peptides and antibodies previously observed in vivo. Increased barrier functionality was accomplished using a developmentally-inspired induction protocol that includes a period of differentiation under hypoxic conditions. This enhanced BBB Chip may therefore represent a new in vitro tool for development and validation of delivery systems that transport drugs and therapeutic antibodies across the human BBB.

3D brain angiogenesis model to reconstitute functional human blood–brain barrier in vitro

“…Recently, a few 3D in vitro BBB spheroids with a functional efflux transport system have been introduced (Bergmann et al, ; C. F. Cho et al, ), but they lack a 3D perfusable vascular network, limiting their potential for drug application through the intraluminal region. Park et al () also described 2D microfluidic BBB model with a functional efflux pump. This was the first in vitro BBB model to show the regulation of efflux transporters and test the selective transcytosis of peptides involved in actual CNS therapeutics.…”

Vascularized Microfluidics and the Blood–Endothelium Interface

“…These impediments include complex tight junctions that restrict paracellular transit [52] and efflux pumps that inhibit the uptake of lipophilic molecules [53]. Using pluripotent stem cell-derived brain microvascular endothelium, astrocytes, and pericytes, Park et al [54] were able to recapitulate the BBB on a perfusable chip, building upon the work of Campisi et al [55]. This endothelium expressed high levels of tight and adherens junction proteins and functional efflux pumps with recapitulation of their documented response to Verapamil in vivo, as well as selective transcytosis of peptides and antibodies.…”

“…Furthermore, it is not well understood whether the use of mature organotypic ECs or pluripotent stem cells are more suitable to these models, and these variations are only just beginning to be explored. Though some models discussed heretofore have taken advantage of organotypic ECs [121] and pluripotent stem cells [54], tapping the potential of vascularized microfluidics is dependent upon their expanded use.…”

“…Of equal importance in the generalizability of vascularized microfluidic experiments to the culturing of diverse ECs is the perfused blood substitute, or biofluid. These biofluids span the completely artificial, as in the case of culture media [54], to the near recapitulation of in vivo systems, as in the case of whole blood [134], with the majority of models employing an intermediate biofluid in the form of cell suspensions [121]. The choice of biofluid reflects the advantages of reductionism in vascularized microfluidics toward the investigation of highly specific blood-endothelial interactions.…”

Lymphoid follicle formation and human vaccination responses recapitulated in an organ-on-a-chip

“…Here, we describe how Organ Chip microfluidic culture technology, which has been successfully used to recapitulate both normal physiology and disease states in multiple other human organs (e.g., lung, intestine, kidney, bone marrow, brain, etc.) (13)(14)(15)(16)(17)(18)(19), can be applied in combination with human bloodderived lymphocytes to create a functional LN model. This human LN chip exhibits spontaneous LF formation, induction of class switching, and plasma cell development in response to bacterial stimuli, antigen-specific Abs, as well as physiologically relevant human vaccination responses to a commercial influenza vaccine.…”