Endothelial progenitor cell recruitment in a microfluidic vascular model

Area of Science:

• Cardiovascular Biology
• Cellular and Molecular Medicine
• Biomedical Engineering

Background:

• Endothelial progenitor cells (EPCs) are crucial for vascular repair following injury.
• Hypoxic conditions and TNF-α signaling in damaged blood vessels upregulate ICAM-1 expression.
• ICAM-1 mediates the attachment of EPCs to the endothelial cell lining.

Purpose of the Study:

• To investigate EPC attachment to endothelial cells under simulated injured blood vessel conditions.
• To evaluate the role of hypoxia and TNF-α in ICAM-1 expression and EPC adhesion.
• To develop and validate a 3D microbioreactor (MBR) system for modeling vascular injury.

Main Methods:

• Human Umbilical Vein Endothelial Cells (HUVECs) were stimulated with varying oxygen levels (atmospheric vs. 1% hypoxia) and TNF-α.
• ICAM-1 expression and endothelial cell-colony forming cell (ECFC) attachment were quantified.
• A novel 3D MBR system was fabricated to control oxygen tension and shear stress.
• HUVECs were cultured within the 3D MBR, followed by ECFC seeding under stimulated conditions.

Main Results:

• Highest ECFC attachment and ICAM-1 expression were observed in HUVECs stimulated with both hypoxia and TNF-α.
• The 3D MBR system demonstrated significantly increased ECFC retention on HUVECs under low shear stress compared to static conditions.
• The system successfully mimicked pathological oxygen tension and shear stress found in damaged vasculature.

Conclusions:

• Hypoxia and TNF-α synergistically enhance ECFC attachment to endothelial cells via ICAM-1.
• The developed 3D MBR system provides a robust platform for studying vascular injury and repair mechanisms.
• This model holds potential for investigating vascular-related disorders and therapeutic interventions.