近日，刊登在美国权威学术杂志《Journal of the American Heart Association 美国心脏协会会刊》上的研究论文中，来自埃默里大学的研究者通过研究，将干细胞包裹于藻酸盐制成的胶囊中，一旦干细胞进入胶囊，其就可以持续稳定地释放愈合因子；文中研究者将装有间质干细胞胶囊应用于发生心脏病的大鼠心脏中，相比不进行治疗的细胞来讲，使用胶囊进行治疗的大鼠心脏功能增强了，而且其心脏疤痕尺寸减小了，一个月后生成了很多心血管。
研究者W.Robert Taylor博士表示，这种方法对于维持细胞功能以及生存非常有效，当将装载有干细胞的胶囊运送到发生心脏病的心脏中时，干细胞就会面对残酷的炎性环境以及机械压力，胶囊的包裹作用使得间质干细胞可以聚集在一起保持活性，而且也可以使得干细胞感知周围的环境，并且释放小型蛋白质，比如生长因子等，最终发挥疗效。
研究者使用人工心脏进行试验，当心脏病发作后使用胶囊一个月后的大鼠，其射血分数（每搏输出量占心室舒张末期容积量的百分比。一般50%以上属于正常范围）为56%，而未经过胶囊治疗的大鼠的射血分数为39%。
研究者表示，在临床环境下，最终的目标是使用病人自身的间充质干细胞来治疗心脏疾病。干细胞胶囊疗法一旦投入规模化应用，世界范围内，成千上万名心脏疾病患者都将会因此而受益。
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J Am Heart Assoc. 2013 Oct 10;2(5):e000367. doi: 10.1161/JAHA.113.000367.
Cellular encapsulation enhances cardiac repair.
Levit RD, Landázuri N, Phelps EA, Brown ME, García AJ, Davis ME, Joseph G, Long R, Safley SA, Suever JD, Lyle AN, Weber CJ, Taylor WR.
SourceDepartment of Medicine, Division of Cardiology, Emory University School of Medicine, Atlanta, 30322, GA.
Abstract
BACKGROUND:Stem cells for cardiac repair have shown promise in preclinical trials, but lower than expected retention, viability, and efficacy.Encapsulation is one potential strategy to increase viable cell retention while facilitating paracrine effects.
METHODS AND RESULTS:Human mesenchymal stem cells (hMSC) were encapsulated in alginate and attached to the heart with a hydrogel patch in a rat myocardial infarction (MI) model. Cells were tracked using bioluminescence (BLI) and cardiac function measured by transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging (CMR). Microvasculature was quantified using von Willebrand factor staining and scar measured by Masson's Trichrome. Post-MI ejection fraction by CMR was greatly improved in encapsulated hMSC-treated animals (MI: 34±3%, MI+Gel: 35±3%, MI+Gel+hMSC: 39±2%, MI+Gel+encapsulated hMSC: 56±1%; n=4 per group; P<0.01). Data represent mean±SEM. By TTE, encapsulated hMSC-treated animals had improved fractional shortening. Longitudinal BLI showed greatest hMSC retention when the cells were encapsulated (P<0.05). Scar size at 28 days was significantly reduced in encapsulated hMSC-treated animals (MI: 12±1%, n=8; MI+Gel: 14±2%, n=7; MI+Gel+hMSC: 14±1%, n=7; MI+Gel+encapsulated hMSC: 7±1%, n=6; P<0.05). There was a large increase in microvascular density in the peri-infarct area (MI: 121±10, n=7; MI+Gel: 153±26, n=5; MI+Gel+hMSC: 198±18, n=7; MI+Gel+encapsulated hMSC: 828±56 vessels/mm(2), n=6; P<0.01).
CONCLUSIONS:Alginate encapsulation improved retention of hMSCs and facilitated paracrine effects such as increased peri-infarct microvasculature and decreased scar. Encapsulation of MSCs improved cardiac function post-MI and represents a new, translatable strategy for optimization of regenerative therapies for cardiovascular diseases.
