How to Construct In Vitro Blood Brain Barrier Models?

The blood-brain barrier (BBB) plays a crucial role in protecting the central nervous system (CNS) from harmful substances while allowing the passage of essential nutrients and molecules. Studying the BBB and its functioning is vital for understanding various neurological disorders and developing effective therapeutic interventions.

Creative Biolabs provides in vitro BBB models that are valuable tools for investigating complex interactions. Here, we will explore the construction of in vitro BBB models, sharing some useful information on BBB model building.

Understanding the BBB

To construct an in vitro BBB model, it is essential to comprehend the unique properties and functions of the BBB. The BBB is a highly selective and semi-permeable barrier composed of specialized brain endothelial cells, tight junction proteins, pericytes, and astrocytes. Its tight junctions restrict the paracellular movement of molecules, while transporters and efflux pumps regulate the transcellular transport of nutrients, drugs, and other substances.

Fig. 1 Overview of characteristics of hIPSC-derived BBB models. (Jagtiani E, et al., 2022)

Cell Types Used in In Vitro BBB Models

• Brain Endothelial Cells
  Primary brain endothelial cells or immortalized cell lines derived from brain capillaries, such as hCMEC/D3, are commonly employed in constructing in vitro BBB models. These cells exhibit characteristics resembling the in vivo BBB, including the expression of tight junction proteins and transporters.
• Pericytes
  Pericytes are mural cells that closely associate with brain endothelial cells. Their presence is essential for maintaining BBB integrity and functionality. Co-culturing brain endothelial cells with pericytes enhances the physiological relevance of the in vitro model.
• Astrocytes
  Astrocytes are abundant glial cells in the CNS and have a crucial role in supporting BBB functions. Co-culturing brain endothelial cells with astrocytes helps mimic the neurovascular unit and provides a more accurate representation of the BBB.

Scaffold Selection for In Vitro BBB Models

The choice of scaffold for constructing the in vitro BBB model significantly impacts its physiological relevance. Various scaffold materials, including hydrogels, polymers, and extracellular matrix components, can be utilized. These scaffolds provide structural support, facilitate cell adhesion, and influence cell behavior. Combining different scaffolds can enhance the functionality of the model, allowing for the representation of varying microenvironments.

Incorporating Flow and Shear Stress

Physiological fluid flow and shear stress have a significant influence on BBB function. Mimicking these dynamic conditions in vitro models is critical to enhancing their physiological relevance. Microfluidic systems and bioreactors can be employed to introduce controlled flow and shear stress, promoting the development of more realistic and functional BBB models.

Assessment of BBB Model Functionality

To evaluate the functionality of in vitro BBB models, several parameters can be assessed. These include transendothelial electrical resistance (TEER), permeability studies using small molecules or therapeutic drugs, efflux transporter activity, and expression of tight junction proteins. Combining different analytical techniques provides a comprehensive assessment of the model.

Constructing in vitro BBB models with a suitable selection of cell types, scaffolds, and incorporation of dynamic conditions provides valuable tools for studying the complexities of the BBB. As technologies continue to evolve, in vitro BBB models will play a vital role in advancing neuroscience research and therapeutic development for various CNS disorders. Creative Biolabs, a leading provider of neuroscience modeling services, provides researchers with best-in-class BBB model-building services. Contact us immediately.

References

1. Naik P and Cucullo L. In vitro blood–brain barrier models: current and perspective technologies. Journal of pharmaceutical sciences, 2012, 101(4): 1337-1354.
2. Jagtiani E, et al. In vitro blood brain barrier models: An overview. Journal of Controlled Release, 2022.

For Research Use Only. Not For Clinical Use.