A Biomimetic Approach Utilizing Pulsatile Perfusion Generates Contractile Vascular Grafts

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Cardiovascular Surgery

Background:

• Current decellularized cadaveric arteries for congenital heart defects lack growth capacity, leading to reoperations.
• Islet-1+ cardiovascular progenitor cells (CPCs) can differentiate into various heart and outflow tract cell types.

Purpose of the Study:

• To create a bioengineered arterial conduit using CPC-seeded decellularized pulmonary arteries cultured under physiologic flow.
• To evaluate if this approach promotes vascular differentiation and results in a more suitable graft for long-term growth.

Main Methods:

• Decellularization of ovine pulmonary arteries and ECM characterization.
• Seeding CPCs onto scaffolds and culturing in static or pulsatile bioreactors.
• Assessing differentiation via immunohistochemistry, PCR, and tissue bath studies.
• Implantation into juvenile sheep to assess graft viability and integration.

Main Results:

• Complete cell removal (>99% DNA reduction) while preserving collagen and elastin.
• Pulsatile culture for 3 weeks induced contractile smooth muscle cell presence (calponin 1, myosin heavy chain 11).
• Engineered graft contraction strength comparable to native tissue; successful implantation in sheep, retaining smooth muscle and recruiting endothelium.

Conclusions:

• Physiologic pulsatile culture promotes CPC differentiation into a mature, contractile phenotype on ECM conduits.
• The bioengineered graft is viable, safe for implantation, and demonstrates potential as an alternative to current treatments.
• Further studies are needed to assess the somatic growth potential of these grafts.