据英国《独立报》1月12日报道，美国研究人员表示，实验首次证明，使用人类胚胎干细胞研制出的血小板可修复实验鼠的受损组织，人类未来有望源源不断地制造出起作用的血小板，捐血有可能成为历史。
血小板是哺乳动物血液中的有形成分之一。血小板在止血、伤口愈合、炎症反应、血栓形成及器官移植排斥等生理和病理过程中有重要作用，接受癌症治疗或器官移植手术的病人常需要血小板来修复受损的身体组织和血管及预防无法控制的大出血。没有血小板，医生将无法快速而准确地治愈病人受损的身体组织，病人也可能因为内出血而死亡。
医生一般从捐赠的血液中提取血小板，然而，血小板不能被冷冻且只能存放7天到10天，如果用血量大，医院常会出现血小板不足的情况，因此，科学家一直在寻找能源源不断制造出血小板的方法，让人们不再需要输血。
美国先进细胞技术公司的科学家使用从多余的试管婴儿胚胎中提取出的干细胞制造出了血小板。科学家先将这些干细胞转变成特殊的巨核细胞，接着在实验室中对其进行培养，最终得到了完全成熟的血小板。研究证明，在将其注入实验鼠体内时，这些血小板能修复老鼠受损的身体组织，就像它们在人体内所做的一样。
该公司首席科学家、人类胚胎干细胞克隆先驱罗伯特·兰扎表示，他们研制出的血小板在外观和工作方式上与捐赠血液中提取出来的血小板一样，也能被血液中天然存在的凝血剂凝血酶所激活。兰扎说：“令人惊奇的是，这些血小板甚至是双凹面的圆盘形，而且，在活的实验鼠中，这些血小板可吸收凝血酶，就像真的血小板一样。科学家可采用这种方法制造出能无限供应、起作用的血小板。”
此外，研究人员还认为，用这种方式制造出的血小板并不包含任何遗传物质，这消除了癌症肿瘤可能进入受体体内的风险，因而不会给病人的健康带来危害，可以在临床治疗中大展拳脚。（生物谷Bioon.com）
生物谷推荐原文出处：
Cell Research doi:10.1038/cr.2011.8.
Platelets generated from human embryonic stem cells are functional in vitro and in the microcirculation of living mice.
Lu SJ, Li F, Yin H, Feng Q, Kimbrel EA, Hahm E, Thon JN, Wang W, Italiano JE, Cho J, Lanza R.
[1] Stem Cell and Regenerative Medicine International, 33 Locke Drive, Marlborough, MA 01752, USA [2] Department of Applied Bioscience, Cha University, Seoul, Korea.
Abstract
Platelets play an essential role in hemostasis and atherothrombosis. Owing to their short storage time, there is constant demand for this life-saving blood component. In this study, we report that it is feasible to generate functional megakaryocytes and platelets from human embryonic stem cells (hESCs) on a large scale. Differential-interference contrast and electron microscopy analyses showed that ultrastructural and morphological features of hESC-derived platelets were indistinguishable from those of normal blood platelets. In functional assays, hESC-derived platelets responded to thrombin stimulation, formed microaggregates, and facilitated clot formation/retraction in vitro. Live cell microscopy demonstrated that hESC-platelets formed lamellipodia and filopodia in response to thrombin activation, and tethered to each other as observed in normal blood. Using real-time intravital imaging with high-speed video microscopy, we have also shown that hESC-derived platelets contribute to developing thrombi at sites of laser-induced vascular injury in mice, providing the first evidence for in vivo functionality of hESC-derived platelets. These results represent an important step toward generating an unlimited supply of platelets for transfusion. Since platelets contain no genetic material, they are ideal candidates for early clinical translation involving human pluripotent stem cells.
