Laboratoire Matière et Systèmes, Complexes MSC, UMR 7057, CNRS & University Paris Diderot, Paris, France.
J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL.
J Tissue Eng Regen Med. 2020 Mar;14(3):510-520. doi: 10.1002/term.3015. Epub 2020 Feb 6.
Recellularization of ex vivo-derived scaffolds remains a significant hurdle primarily due to the scaffolds subcellular pore size that restricts initial cell seeding to the scaffolds periphery and inhibits migration over time. With the aim to improve cell migration, repopulation, and graft mechanics, the effects of a four-step culture approach were assessed. Using an ex vivo-derived vein as a model scaffold, human smooth muscle cells were first seeded onto its ablumen (Step 1: 3 hr) and an aggressive 0-100% nutrient gradient (lumenal flow under hypotensive pressure) was created to initiate cell migration across the scaffold (Step 2: Day 0 to 19). The effects of a prolonged aggressive nutrient gradient created by this single lumenal flow was then compared with a dual flow (lumenal and ablumenal) in Step 3 (Day 20 to 30). Analyses showed that a single lumenal flow maintained for 30 days resulted in a higher proportion of cells migrating across the scaffold toward the vessel lumen (nutrient source), with improved distribution. In Step 4 (Day 31 to 45), the transition from hypotensive pressure (12/8 mmHg) to normotensive (arterial-like) pressure (120/80 mmHg) was assessed. It demonstrated that recellularized scaffolds exposed to arterial pressures have increased glycosaminoglycan deposition, physiological modulus, and Young's modulus. By using this stepwise conditioning, the challenging recellularization of a vein-based scaffold and its positive remodeling toward arterial biomechanics were obtained.
细胞再植化(ex vivo-derived scaffolds)仍然是一个重大的障碍，主要是由于支架的亚细胞孔径限制了初始细胞接种到支架的外围，并随着时间的推移抑制了迁移。为了改善细胞迁移、再植和移植物力学性能，评估了四步培养方法的效果。使用体外衍生的静脉作为模型支架，首先将人平滑肌细胞接种到其内膜上（第 1 步：3 小时），并创建一个激进的 0-100%营养梯度（低压下的内腔流），以启动细胞穿过支架的迁移（第 2 步：第 0 天至第 19 天）。然后，将这种单一内腔流产生的长期激进营养梯度的效果与第 3 步（第 20 天至第 30 天）中的双流（内腔和内膜）进行了比较。分析表明，维持 30 天的单一内腔流导致更多的细胞穿过支架向血管内腔（营养源）迁移，并且分布得到改善。在第 4 步（第 31 天至第 45 天）中，评估了从低血压（12/8mmHg）到正常血压（类似动脉）（120/80mmHg）的转变。结果表明，暴露于动脉压的再细胞化支架具有增加的糖胺聚糖沉积、生理模量和杨氏模量。通过使用这种逐步调理，获得了基于静脉的支架的挑战性再细胞化及其向动脉生物力学的积极重塑。
