Interstitial flow regulates in vitro three-dimensional self-organized brain micro-vessels.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Cell Biology

Background:

• Human brain microvascular endothelial cells (HBMECs) are crucial for blood-brain barrier (BBB) function.
• Static cell cultures do not fully replicate the complex microenvironment of the brain vasculature.
• Medium flow has been previously shown to improve HBMEC function and maturation.

Purpose of the Study:

• To develop and characterize a novel 3D in vitro model of the human brain microvasculature.
• To investigate the effects of continuous medium flow on the self-organization and function of brain microvascular networks.
• To assess the impact of interstitial flow on BBB properties within the 3D model.

Main Methods:

• A 3D in vitro model was created using HBMECs, astrocytes, pericytes, and a collagen type I microfiber-fibrin matrix.
• The model was cultured in a pressure-driven microphysiological system with continuous medium flow (10 kPa, 60-30 s cycles).
• Comparison between static and dynamic (flow) culture conditions was performed to evaluate micro-vessel network formation and gene/protein expression.

Main Results:

• Cells self-organized into micro-vessels oriented perpendicular to the shear flow.
• Interstitial flow resulted in a more defined micro-vasculature network with increased lumen formation compared to static cultures.
• A higher expression of genes and proteins related to transporters, carriers, and tight junctions was observed under flow conditions.

Conclusions:

• The 3D dynamic culture system effectively mimics the human brain microvasculature.
• Continuous medium flow significantly enhances the development and functional characteristics of the BBB model.
• This advanced model provides a valuable tool for studying blood-brain barrier function and related neurological disorders.