Self-assembled Collagen-Fibrin Hydrogel Reinforces Tissue Engineered Adventitia Vessels Seeded with Human Fibroblasts

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Vascular Biology

Background:

• Vascular graft engineering often prioritizes tunica media and intima, neglecting the tunica adventitia's crucial role in structural support.
• Surgical procedures like endarterectomy can leave the adventitia as the primary layer for vessel closure, highlighting its importance.

Purpose of the Study:

• To adapt a tissue ring stacking technique for creating adventitia vascular grafts using human fibroblasts.
• To optimize hydrogel composition and culture conditions for enhanced mechanical properties and extracellular matrix deposition.

Main Methods:

• Human fibroblasts were cultured in fibrin hydrogels, forming tubular structures via stacked rings.
• Collagen type I gel (0.7, 1.7, 2.2 mg/ml) was incorporated into the fibrin hydrogel base.
• Transforming growth factor-beta (TGF-β) and ascorbic acid were used to augment collagen production and cross-linking.
• Tensile strength, failure strength, and histological analysis were performed after 8 days and 1-2 weeks of culture.

Main Results:

• The engineered adventitia vessels achieved significant tensile strength (57.8 ± 3.07 kPa) with TGF-β and ascorbic acid treatment.
• Incorporation of 0.7 mg/ml collagen into the fibrin hydrogel yielded the highest tensile strength (77.0 ± 18.1 kPa).
• Extended culture periods (1-2 weeks) increased extracellular matrix deposition and failure strength.
• Histological analysis confirmed superior collagen maturation in the 0.7 mg/ml collagen group.

Conclusions:

• A fibrin hydrogel incorporating 0.7 mg/ml collagen is optimal for creating and strengthening engineered adventitia vessels.
• This approach offers a promising strategy for developing vascular grafts with enhanced structural integrity.