Objective:

To develop three-dimensional heart valve-like tissues from human pluripotent stem cells that mimic features of inflammatory heart valve disease and native human valves.

Approach:

• Cell Line Testing: Three human pluripotent stem cell lines were used: PB522.3 iPSCs, PB10.5 iPSCs, and HES3 ESCs.
• Tissue Engineering: Cells were incorporated into valve-engineered tissues (VET) in microVETs and macroVETs for various assessments.
• Proteomic and Transcriptomic Analysis: Proteomic analysis compared 2D stem cell-derived cells with macroVETs, while transcriptomic analysis assessed gene expression.
• Inflammatory Disease Modeling: MicroVETs were exposed to inflammatory cytokines to model inflammatory valve disease.
• Biomechanical Assessment: MacroVETs were implanted subcutaneously in rats to evaluate biomechanical properties.

Key Findings:

• 85% of cells expressed the valve interstitial cell lineage marker SOX9 after 15 days.
• 3D culture promoted a more mature valve-like molecular profile with significant protein expression changes.
• 99.7% of native valve proteins were expressed in macroVETs.
• Inflammatory cytokine exposure increased tissue tension and markers of extracellular matrix pathology.
• MacroVETs showed no evidence of degradation or calcification in rat implantation studies.

Interpretation:

VETs serve as a platform for studying human valve development, maturation, and inflammatory disease.

Limitations:

• VETs did not fully replicate native valve cellular composition, particularly with underrepresentation of valve endothelial cells.
• The tissues lacked an organized endothelial layer and high levels of elastin.
• Biomechanical properties of macroVETs were inferior to human aortic valves.

Conclusion:

Further development is needed to enhance the biomechanical properties of VETs.

Sources:

• Cell Stem Cell