Arterial graft with elastic layer structure grown from cells.

Area of Science:

• Biomedical Engineering
• Regenerative Medicine
• Vascular Biology

Background:

• Limited availability of autologous blood vessels and limitations of synthetic grafts drive research into tissue-engineered vascular grafts.
• The tunica media layer, crucial for arterial elasticity, is challenging to synthesize using current methods.

Purpose of the Study:

• To develop a novel method for fabricating elastic arterial grafts with a layered structure using vascular smooth muscle cells (SMCs).
• To investigate the potential therapeutic applications of these engineered grafts for cardiovascular diseases.

Main Methods:

• Cultured human vascular SMCs were subjected to periodic, extremely high hydrostatic pressure (HP) cycles (110–180 kPa at 0.002 Hz).
• This process, involving repeated cell seeding and HP exposure (ten cycles), promoted stress-fiber polymerization and fibronectin fibrillogenesis, essential for elastic fiber formation.
• Rat vascular SMCs were used to fabricate medial grafts, which were then tested in rat aorta models.

Main Results:

• The engineered medial grafts exhibited high elasticity and tensile rupture strength (1451 ± 159 mmHg) due to abundant elastic fiber formation.
• Patch medial grafts sutured into rat aortas remained patent and endothelialized after 2.5 months.
• Tubular medial constructs, however, only withstood arterial blood pressure in the acute phase when used as interpositional grafts.

Conclusions:

• A novel, organized self-assembly method enables the in vitro mass production of scaffold-free arterial grafts with elastic layer structure.
• This technique holds significant potential for therapeutic applications in treating cardiovascular diseases, particularly for patch-graft applications.