Tissue Engineering and Regenerative Medicine Laboratory, Columbia University Medical Center, New York, New York 10032, USA.
Tissue Eng Part A. 2010 Nov;16(11):3299-307. doi: 10.1089/ten.TEA.2010.0157. Epub 2010 Jul 14.
A critical barrier in tissue regeneration is scale-up. Bioengineered adipose tissue implants have been limited to ∼10 mm in diameter. Here, we devised a 40-mm hybrid implant with a cellular layer encapsulating an acellular core. Human adipose-derived stem cells (ASCs) were seeded in alginate. Poly(ethylene)glycol-diacrylate (PEGDA) was photopolymerized into 40-mm-diameter dome-shaped gel. Alginate-ASC suspension was painted onto PEGDA surface. Cultivation of hybrid constructs ex vivo in adipogenic medium for 28 days showed no delamination. Upon 4-week in vivo implantation in athymic rats, hybrid implants well integrated with host subcutaneous tissue and could only be surgically separated. Vascularized adipose tissue regenerated in the thin, painted alginate layer only if ASC-derived adipogenic cells were delivered. Contrastingly, abundant fibrous tissue filled ASC-free alginate layer encapsulating the acellular PEGDA core in control implants. Human-specific peroxisome proliferator-activated receptor-γ (PPAR-γ) was detected in human ASC-seeded implants. Interestingly, rat-specific PPAR-γ was absent in either human ASC-seeded or ASC-free implants. Glycerol content in ASC-delivered implants was significantly greater than that in ASC-free implants. Remarkably, rat-specific platelet/endothelial cell adhesion molecule (PECAM) was detected in both ASC-seeded and ASC-free implants, suggesting anastomosis of vasculature in bioengineered tissue with host blood vessels. Human nuclear staining revealed that a substantial number of adipocytes were of human origin, whereas endothelial cells of vascular wall were of chemaric human and nonhuman (rat host) origins. Together, hybrid implant appears to be a viable scale-up approach with volumetric retention attributable primarily to the acellular biomaterial core, and yet has a biologically viable cellular interface with the host. The present 40-mm soft tissue implant may serve as a biomaterial tissue expander for reconstruction of lumpectomy defects.
组织再生的一个关键障碍是规模扩大。生物工程脂肪组织植入物的直径一直限制在约 10mm 以内。在这里，我们设计了一种 40mm 的混合植入物，具有包裹无细胞核心的细胞层。人脂肪来源干细胞（ASCs）接种在藻酸盐中。聚乙二醇二丙烯酸酯（PEGDA）被光聚合形成 40mm 直径的圆顶状凝胶。藻酸盐-ASC 悬浮液涂覆在 PEGDA 表面。在体外脂肪生成培养基中培养 28 天的杂交构建体没有分层。在无胸腺大鼠体内植入 4 周后，杂交植入物与宿主皮下组织很好地整合在一起，只能通过手术分离。只有在 ASC 衍生的脂肪细胞被递送的情况下，才能在薄的、涂覆的藻酸盐层中再生血管化的脂肪组织。相反，在对照植入物中，无 ASC 的藻酸盐层中充满了丰富的纤维组织，而藻酸盐层则包裹着无细胞的 PEGDA 核心。在人 ASC 接种的植入物中检测到人类特异性过氧化物酶体增殖物激活受体-γ（PPAR-γ）。有趣的是，无论是在人 ASC 接种的还是无 ASC 的植入物中，都没有检测到大鼠特异性 PPAR-γ。在 ASC 递送的植入物中甘油含量明显大于无 ASC 的植入物。值得注意的是，在 ASC 接种的和无 ASC 的植入物中都检测到了大鼠特异性血小板/内皮细胞黏附分子（PECAM），这表明生物工程组织中的血管与宿主血管吻合。人核染色显示，大量脂肪细胞来源于人类，而血管壁的内皮细胞则来源于化学性人类和非人类（大鼠宿主）来源。总之，混合植入物似乎是一种可行的规模扩大方法，其体积保留主要归因于无细胞生物材料核心，并且与宿主具有生物上可行的细胞界面。目前的 40mm 软组织植入物可用作乳房切除术缺陷重建的生物材料组织扩张器。
