First human liver made from stem cells

Kounteya Sinha, TNN Jul 5, 2013, 05.00AM IST

LONDON: Japanese scientists have for the first time grown a functional human liver tissue from stem cells. The breakthrough opens up the possibility of growing human organs in the lab, thus paving way for ending critical shortage of donor organs.

Though it could take a decade to actually grow organs on a large scale for transplants, the latest study by Japanese scientists using stem cells derived from skin and blood are being looked at as "proof of concept." Takanori Takebe and Hideki Taniguchi at Yokohama City University showed the generation of vascularized and functional human liver from human-induced pluripotent stem cells (hiPSCs) by transplantation of in-vitro grown liver buds (rudimentary liver).

This study also demonstrates a proof-of-concept that organ bud transplantation can be an alternative approach for treating organ failure by generating a 3D and vascularized organ. Critical shortage of donor organs for treating end-stage organ failure highlights the urgent need for generating organs from pluripotent stem cells.

Despite many reports describing functional "cell" differentiation, no studies so far have succeeded in generating a three-dimensional vascularized "organ" such as liver so far, according to the researchers. This study, published in the journal Nature on Thursday, says that since the discovery of embryonic stem cells in 1981, decades of laboratory studies have failed to generate a complex vascularized organ such as liver from pluripotent stem cells (PSCs), giving rise to the prevailing belief that in-vitro recapitulation of the complex interactions among cells and tissues during organogenesis is considered to be essentially impractical.

So the experts actually used the iPS cells to create the three different cell types that are actually required for the natural formation of a human liver in an embryo hepatic endoderm cells, mesenchymal stem cells and endothelial cells. Scientists then mixed them together with the hope to see them grow.

To their amazement, the cells went on to form a threedimensional structure called liver buds, a mixture of liver cells that can develop into a full organ. When they transplanted them into mice, the researchers saw the human liver buds mature, following which they began to perform many of the functions of mature human liver cells.

The scientists said, "Manipulation of iPSCs holds great promise for regenerative medicine. However, clinical trials of "cell transplantation", that is a current main target of stem cell-based approach, have presented unsatisfactory results."

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First human liver made from stem cells