Amnion-Based Scaffold with Enhanced Strength and Biocompatibility for In Vivo Vascular Repair

Abstract

Current vascular replacement grafts used in congenital heart defect corrective surgery have poor longevity and growth potential. Recipient patients often require multiple reoperations. Tissue engineering has the promise to produce a graft with the potential to grow, remodel and repair. Here we aimed at developing an amnion-based scaffold suitable for cardiovascular tissue engineering applications and in vivo usage. The developed human amnion-based scaffold was made by an enzymatic decellularization process followed by freeze-drying as a single or multi-layered structure. These structures were compared to native amnion for seeded cell viability and biomechanical properties then tested for in vivo biocompatibility. Our results demonstrated that while native amnion tissue supported little cell growth, the decellularized-amnion allowed cell engraftment and proliferation cell survival. Additionally, preservation of the scaffold by freeze-drying as a single layer, allowed further improved cell engraftment and cell growth. Multi-layering the freeze-dried amnion-scaffolds resulted in a similar cell growth potential of the single layered construct but superior mechanical strength. The multi-layered construct showed in vitro biocompatibility with endothelial cells, smooth muscle cells, cardiac myocytes, and thymus and cord-blood-derived MSCs. When implanted in a piglet model of left pulmonary artery grafting, the multi-layered construct showed its in vivo suitability and biocompatibility for vascular repair as demonstrated by the development of newly formed endothelium in the intima, a smooth muscle cell-rich medial layer and an adventitia containing new vasa vasorum. endothelial cell layer in the inner side of the graft and a smooth muscle layer in the outer side. In conclusion, our developed amnion-derived scaffold represents an off-the-shelf biocompatible structure that can be seeded with the patient's own MSCs to produce an autologous vascular graft.

Tissue-Engineered Grafts from Human Decellularized Extracellular Matrices: A Systematic Review and Future Perspectives

“…In particular, acellular amniotic membrane was investigated as a scaffold to support/deliver epithelial cells [240], limbal stem cells [296], human adipose stem cells [297], differentiated neural-like cells [298], mice ovarian follicular culture [299], as well as a scaffold with cell-guiding ability [300] but it may also be used as a surgical patch/mesh [301] for reconstruction of vessels [302] (also once rolled up [303,304]); bladder [305] or circumferential urethral defect [306], reconstruction of esophageal wall [307], cardiac [120,308] and cerebrospinal fluid [308] applications, endometrial fibrosis treatment [309], soft tissue damage, limbal stem cell deficiency [293], skin defects also due to ulcers or severe skin burns or for corneal defects [310,311,312], treatment of pharyngocutaneous fistula after total laryngectomy [291], and for fetoscopic closure of iatrogenic defects in fetal membranes [313].…”

“…Several decellularization methods were approached, often combining multiple phases based on physical (freezing–thawing), osmotic-chemical (Triton X-100, SDS, EDTA, Tris, NaOH, NH 4 Cl) and/or enzymatic (trypsin, dispase, lipase, DNase, and RNase) treatments [120,234,289,291,292,293,294,296,297,298,299,300,301,302,303,304,305,306,307,308,309,311,312,313,314,315,317,318,319].…”

“…Acellular human amniotic membrane also demonstrated to support different types of stem and nonstem cells. Stem/progenitor cells considered for recellularization were the following: rat bone marrow MSCs, differentiated toward neural [308], adipogenic and osteogenic lineages [314]; rabbit limbal stem cells [293]; human epicardial progenitor cells [144]; adipose derived MSCs [297,312]; human amniotic [298,313]; Wharton´s jelly MSCs, differentiated into neural-like cells [298]; rat bone marrow stromal cells [315]; human telomerase-immortalized corneal epithelial cells (tHCEC), primary limbal epithelial stem cells (LESC), LESC-derived human induced pluripotent stem cells, or skin fibroblast-derived human induced pluripotent stem cells [296]; thymus and cord-blood-derived MSCs [302]; bone marrow MSCs; and EPCs from canine new stillbirth bone marrow [306].…”

“…Various nonstem cells were also investiganted and showed good repopulation properties: rabbit macrophages [293]; murine HL-1 cells and human immune cells derived from buffy coat [144]; mice primary follicles [299]; human keratinocytes [311]; porcine oral epithelial cells [307]; human amniotic epithelial cells [298,313]; fibroblasts (mouse embryonic—NIH3T3; human cardiac, foreskin, dermal, and nasal turbinate) [144,311,313,316,317,318]; rabbit, mouse, and human smooth muscle cells [301,305]; cardiac myocytes, [302]; human skeletal muscle cells [300]; human endothelial cells [302,303,313]; human chondrocytes [313].…”

“…The in vivo behavior of AM-derived scaffolds was evaluated in: rat model of intrauterine adhesion [306]; third-degree skin burns in BALB/c mice [312]; full-thickness skin defects in Sprague Dawley rats [310]; patients experiencing pharyngocutaneous fistula because of surgical treatment of laryngeal squamous cell carcinoma [291]; BALB/c mice in which myocardial infarction was induced [319]; uterus of rabbits [301]; subcutaneously in the left hemiback of rats [316]; in the left pulmonary artery of pig after a left posterolateral thoracotomy [302]; in dogs urethral defect model [306]; for closure of fetoscopic entry wounds in the exposed rabbit amniotic sac [313]; and deep flexor tendon of the chicken toe [320].…”