Induced pluripotent stem cells and cell therapy

Abstract

Human embryonic stem cells are derived from the inner cell mass of a blastocyst-stage embryo. They hold a huge promise for cell therapy with their self-renewing ability and pluripotency, which is known as the potential to differentiate into all cell types originating from three embryonic germ layers. However, their unique pluripotent feature could not be utilised for therapeutic purposes due to the ethical and legal problems during derivation. Recently, it was shown that the cells from adult tissues could be reverted into embryonic state, thereby restoring their pluripotent feature. This has strenghtened the possiblity of directed differentition of the reprogrammed somatic cells into the desired cell types in vitro and their use in regenerative medicine. Although these cells were termed as induced pluripotent cells, the mechanism of pluripotency has yet to be understood. Still, induced pluripotent stem cell technology is considered to be significant by proposing novel approaches in disease modelling, drug screening and cell therapy. Besides their self-renewing ability and their potential to differentiate into all cell types in a human body, they arouse a great interest in scientific world by being far from the ethical concerns regarding their embryonic counterparts and their unique feature of being patient-specific in prospective cell therapies. In this review, induced pluripotent stem cell technology and its role in cell-based therapies from past to present will be discussed. J Clin Exp Invest 2013; 4 (4): 550-561

Keywords

• Induced pluripotent stem cells, pluripotent stem cells, embryonic stem cells, regenerative medicine

İndüklenmiş pluripotent kök hücreler ve hücre tedavisi

Öz

İnsan embriyonik kök hücreleri embriyonun blastosist aşamasındaki iç hücre kitlesinden elde edilir. Kendi kendilerini sınırsız yenileyebilme özelliklerinin yanında pluripotent olmaları, yani üç farklı embriyonik tabakadan köken alan hücre tiplerine farklılaşabilme potansiyelleri ile hücre tedavisine yönelik büyük umut vaat etmektedirler. Ancak derivasyonlarındaki etik ve yasal problemler nedeniyle, pluripotent özelliklerinin tedavi amaçlı kullanımı henüz gerçekleştirilememektedir. Son yıllarda, erişkin dokulardan elde edilen hücrelerin yeniden programlanarak embriyonik karakter taşıyan pluripotent özellikteki hücrelere dönüşebilecekleri gösterilmiştir. Böylelikle, yeniden programlanan somatik hücrelerin, in vitro olarak istenilen hücre tipine yönlendirilmiş farklılaştırılması ve rejeneratif tıp alanında kullanılma ihtimali kuvvetlenmiştir. Pluripotent özellik kazandırılan bu hücreler indüklenmiş pluripotent kök hücreler olarak tanımlanmış olsa da, pluripotent özelliğin mekanizması henüz tam anlamıyla açıklanamamıştır. Yine de, indüklenmiş pluripotent kök hücre teknolojisi, insan hastalık modellerinin çalışılması, yeni ilaç geliştirilmesi ve hücre tedavisine yönelik yeni yaklaşımlar önermesi açısından önem arzetmektedir. Kendi kendilerini yenileyebilmeleri ve insan vücudundaki tüm hücre tiplerine farklılaşabilme potansiyellerinin yanında, embriyonik kök hücrelerin neden olduğu etik kaygılardan uzak olmaları ve olası hücre tedavisi uygulamalarında hastaya özgü tasarlanabilecek olmaları nedeniyle son yıllarda bilim dünyasında büyük ilgi uyandırmaktadırlar. Bu derlemede geçmişten günümüze indüklenmiş pluripotent kök hücre teknolojisine ve bu hücre grubunun hücre tedavisindeki yerine değinilecektir.

Anahtar Kelimeler

• İndüklenmiş pluripotent kök hücreler, pluripotent kök hücreler, embriyonik kök hücreler, rejeneratif tıp

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