Three-dimensional printed trileaflet valve conduits using biological hydrogels and human valve interstitial cells

Abstract

Tissue engineering has great potential to provide a functional de novo living valve replacement capable of integration with host tissue and growth. Among various valve conduit fabrication techniques, 3D bioprinting enables deposition of cells and hydrogels into 3D constructs with anatomical geometry and heterogeneous mechanical properties. Successful translation of this approach is however constrained by the dearth of printable and biocompatible hydrogel materials. Furthermore, it is not known how human valve cells respond to these printed environments. In this study, we develop 3D printable formulations of hybrid hydrogels based on methacrylated hyaluronic acid (Me-HA) and methacrylated gelatin (Me-Gel), and utilize them to bioprint heart valve conduits containing encapsulated human aortic valvular interstitial cells (HAVIC). Increasing Me-Gel concentration resulted in lower stiffness and higher viscosity, facilitated cell spreading, and better maintained HAVIC fibroblastic phenotype. Bioprinting accuracy was dependent upon the relative concentrations of Me-Gel and Me-HA, but when optimized enabled the fabrication of a trileaflet valve shape accurate to the original design. HAVIC encapsulated within bioprinted heart valves maintained high viability, and remodeled the initial matrix by depositing collagen and glyosaminoglycans. These findings represent the first rational design of bioprinted trileaflet valve hydrogels that regulate encapsulated human VIC behavior. The use of anatomically accurate living valve scaffolds through bioprinting may accelerate our understanding of physiological valve cell interactions and our progress towards de novo living valve replacements.

3D bioprinting for tissue engineering: Stem cells in hydrogels

“…A study on methacrylated hyaluronic acid combined with methacrylated gelatin showed that not only could cell viability be maintained but by varying the concentrations of the two materials, the stiffness and viscosity of the hybrid could be controlled [83] . Other researchers have used a similar approach to bioprint scaffolds for a range of uses, including cartilage engineering [84] and to tune material properties for a range of scaffolds [85] .…”

Comparison of Mesenchymal Stem Cell Source Differentiation Toward Human Pediatric Aortic Valve Interstitial Cells within 3D Engineered Matrices

“…29 Cells were cultured in HAVIC growth medium (HGM) containing MCDB131 medium (Sigma), 10% fetal bovine serum (FBS; Invitrogen), 1% penicillin/streptomycin (P/ S; Invitrogen), 0.25 mg/L recombinant human fibroblast growth factor basic (rhbFGF; PeproTech), and 5 mg/L recombinant human epidermal growth factor (rhEGF; Invitrogen). 28,30,31 Cells were used at passages 4-8. Established primary human ADMSC and BMMSC were purchased from Lonza and cultured in stem cell growth medium (GM) containing DMEM/F12 medium (Invitrogen), 10% FBS, and 1% P/S.…”

“…These valve leaflets exhibited normal dynamics via clinical echo, absence of calcific deposits, and no thickened lesions that are characteristic of aortic valve disease that is not present in valves. 28 Tissue was procured with consent as approved by the Institutional Review Board of WeillCornell Medical College in New York City as previously described. 29 Cells were cultured in HAVIC growth medium (HGM) containing MCDB131 medium (Sigma), 10% fetal bovine serum (FBS; Invitrogen), 1% penicillin/streptomycin (P/ S; Invitrogen), 0.25 mg/L recombinant human fibroblast growth factor basic (rhbFGF; PeproTech), and 5 mg/L recombinant human epidermal growth factor (rhEGF; Invitrogen).…”

“…28 The constructs (n = 4-5 per condition) were digested with 300 mg/mL papain in 50 mM phosphate buffer (pH 6.5), containing 5 mM cysteine and 5 mM EDTA for 16 h at 60°C. GAG concentration was calculated by calibrating against a standard curve obtained with shark chondroitin sulfate (Sigma).…”

Stem cells in three-dimensional bioprinting: Future perspectives

“…Stem cells combined with bioprinting create new possibilities regarding regenerative medicine (1). For example, layered skin tissue and intricate structures, such as a heart valve and vasculature, have been created using this technology (2)(3)(4).…”