Sugiura Tadahisa, Hibino Narutoshi, Breuer Christopher K, Shinoka Toshiharu
Tissue Engineering Program and Surgical Research, Nationwide Children's Hospital, Columbus, OH, USA.
Department of Cardiothoracic Surgery, The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA.
J Cardiothorac Surg. 2016 Dec 1;11(1):163. doi: 10.1186/s13019-016-0559-z.
Thousands of babies are born with congenital heart defects that require surgical repair involving a prosthetic implant. Lack of growth in prosthetic grafts is especially detrimental in pediatric surgery. Cell seeded biodegradable tissue engineered grafts are a novel solution to this problem. The purpose of the present study is to evaluate the feasibility of seeding human induced pluripotent stem cell derived cardiomyocytes (hiPS-CMs) onto a biodegradable cardiac patch.
The hiPS-CMs were cultured on a biodegradable patch composed of a polyglycolic acid (PGA) and a 50:50 poly (l-lactic-co-ε-caprolactone) copolymer (PLCL) for 1 week. Male athymic rats were randomly divided into 2 groups of 10 animals each: 1. hiPS-CM seeded group, and 2. Unseeded group. After culture, the cardiac patch was implanted to repair a defect with a diameter of 2 mm created in the right ventricular outflow tract (RVOT) wall. Hearts were explanted at 4 (n = 2), 8 (n = 2), and 16 (n = 6) weeks after patch implantation. Explanted patches were assessed immunohistochemically.
Seeded patch explants did not stain positive for α-actinin (marker of cardiomyocytes) at the 4 week time point, suggesting that the cultured hiPS-CMs evacuated the patch in the early phase of tissue remodeling. However, after 16 weeks implantation, the area fraction of positively stained α-actinin cells was significantly higher in the seeded group than in the unseeded group (Seeded group: 6.1 ± 2.8% vs. Unseeded group: 0.95 ± 0.50%, p = 0.004), suggesting cell seeding promoted regenerative proliferation of host cardiomyocytes.
Seeded hiPS-CMs were not present in the patch after 4 weeks. However, we surmise that they influenced the regeneration of host cardiomyocytes via a paracrine mechanism. Tissue-engineered hiPS-CMs seeded cardiac patches warrant further investigation for use in the repair of congenital heart diseases.
数以千计的婴儿出生时患有先天性心脏缺陷，需要进行涉及人工植入物的手术修复。人工移植物生长不足在小儿外科手术中尤其有害。细胞接种的可生物降解组织工程移植物是解决这一问题的新方法。本研究的目的是评估将人诱导多能干细胞衍生的心肌细胞（hiPS-CMs）接种到可生物降解心脏补片上的可行性。
将hiPS-CMs在由聚乙醇酸（PGA）和50:50聚（L-乳酸-共-ε-己内酯）共聚物（PLCL）组成的可生物降解补片上培养1周。雄性无胸腺大鼠随机分为2组，每组10只动物：1. hiPS-CM接种组，2. 未接种组。培养后，将心脏补片植入修复右心室流出道（RVOT）壁上形成的直径2mm的缺损。在补片植入后4周（n = 2）、8周（n = 2）和16周（n = 6）取出心脏。对取出的补片进行免疫组织化学评估。
接种补片的外植体在4周时间点α-肌动蛋白（心肌细胞标志物）染色未呈阳性，表明培养的hiPS-CMs在组织重塑早期从补片中排出。然而，植入16周后，接种组阳性染色的α-肌动蛋白细胞面积分数显著高于未接种组（接种组：6.1±2.8% vs. 未接种组：0.95±0.50%，p = 0.004），表明细胞接种促进了宿主心肌细胞的再生增殖。
4周后补片中不存在接种的hiPS-CMs。然而，我们推测它们通过旁分泌机制影响宿主心肌细胞的再生。接种hiPS-CMs的组织工程心脏补片在先天性心脏病修复中的应用值得进一步研究。
