Fibrous heart valve leaflet substrate with native-mimicked morphology.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cardiovascular Research

Background:

• Prosthetic heart valves have limitations, driving the need for tissue-engineered alternatives.
• Mimicking the native heart valve's trilayered, oriented structure is crucial for long-term functionality.
• Existing tissue engineering approaches require scaffolds that replicate leaflet microarchitecture.

Purpose of the Study:

• To develop and evaluate trilayered microfibrous leaflet substrates for *in vivo* tissue engineering.
• To assess the structural and mechanical properties of engineered heart valve constructs.
• To investigate cellular responses and extracellular matrix deposition within the scaffolds.

Main Methods:

• Electrospinning was used to create trilayered microfibrous scaffolds with distinct layer orientations (circumferential, random, radial).
• Scaffolds were implanted subcutaneously in rats for *in vivo* tissue engineering assessment.
• Histological analysis, biochemical assays (collagen, GAGs, elastin), tensile testing, and gene/protein expression analysis (vimentin, α-SMA) were performed.

Main Results:

• The engineered constructs exhibited a well-defined trilayered structure mirroring native leaflets.
• Significant deposition of key extracellular matrix components (collagen, GAGs, elastin) was observed.
• The constructs displayed anisotropic tensile properties capable of withstanding physiological loads.
• Residing cells expressed vimentin and α-smooth muscle actin, indicating myofibroblast differentiation.

Conclusions:

• The trilayered structure and anisotropic properties are critical for developing functional heart valve tissue constructs.
• The developed leaflet substrates show significant potential for fabricating scaffolds for heart valve replacement therapies.
• This approach advances the field of tissue-engineered cardiovascular devices.