Schmitt Trevor, Katz Nathan, Kishore Vipuil
Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States.
Jointechlabs Inc., North Barrington, IL, United States.
Front Bioeng Biotechnol. 2021 Jul 27;9:707098. doi: 10.3389/fbioe.2021.707098. eCollection 2021.
Chronic wounds affect over 400,000 people in the United States alone, with up to 60,000 deaths each year from non-healing ulcerations. Tissue grafting (e.g., autografts, allografts, and xenografts) and synthetic skin substitutes are common treatment methods, but most solutions are limited to symptomatic treatment and do not address the underlying causes of the chronic wound. Use of fat grafts for wound healing applications has demonstrated promise but these grafts suffer from low cell viability and poor retention at the wound site resulting in suboptimal healing of chronic wounds. Herein, we report on an innovative closed-loop fat processing system (MiniTC) that can efficiently process lipoaspirates into microfat clusters comprising of highly viable regenerative cell population (i.e., adipose stromal cells, endothelial progenitors) preserved in their native niche. Cryopreservation of MiniTC isolated microfat retained cell count and viability. To improve microfat retention and engraftment at the wound site, microfat was mixed with methacrylated collagen (CMA) bioink and 3D printed to generate microfat-laden collagen constructs. Modulating the concentration of microfat in CMA constructs had no effect on print fidelity or stability of the printed constructs. Results from the Alamar blue assay showed that the cells remain viable and metabolically active in microfat-laden collagen constructs for up to 10 days . Further, quantitative assessment of cell culture medium over time using ELISA revealed a temporal expression of proinflammatory and anti-inflammatory cytokines indicative of wound healing microenvironment progression. Together, these results demonstrate that 3D bioprinting of microfat-laden collagen constructs is a promising approach to generate viable microfat grafts for potential use in treatment of non-healing chronic wounds.
仅在美国，慢性伤口就影响着超过40万人，每年有多达6万人死于无法愈合的溃疡。组织移植（如自体移植、同种异体移植和异种移植）以及合成皮肤替代品是常见的治疗方法，但大多数解决方案仅限于对症治疗，并未解决慢性伤口的根本原因。将脂肪移植用于伤口愈合已显示出前景，但这些移植存在细胞活力低和在伤口部位留存不佳的问题，导致慢性伤口愈合效果不理想。在此，我们报告了一种创新的闭环脂肪处理系统（MiniTC），它可以有效地将抽脂物加工成微脂肪簇，这些微脂肪簇由保存在其天然微环境中的高活力再生细胞群体（即脂肪基质细胞、内皮祖细胞）组成。对MiniTC分离出的微脂肪进行冷冻保存可保持细胞数量和活力。为了提高微脂肪在伤口部位的留存和植入，将微脂肪与甲基丙烯酸化胶原蛋白（CMA）生物墨水混合并进行3D打印，以生成载有微脂肪的胶原蛋白构建体。调节CMA构建体中微脂肪的浓度对打印精度或打印构建体的稳定性没有影响。alamar蓝测定法的结果表明，载有微脂肪的胶原蛋白构建体中的细胞在长达10天的时间内仍保持活力且代谢活跃。此外，使用酶联免疫吸附测定法对细胞培养基随时间进行的定量评估揭示了促炎和抗炎细胞因子的时间表达，这表明伤口愈合微环境在进展。总之，这些结果表明，载有微脂肪的胶原蛋白构建体的3D生物打印是一种有前景的方法，可生成有活力的微脂肪移植物，用于治疗无法愈合的慢性伤口。
