Building a new liver and H7N9 reveals its dark side

Two notable press releases from Japan and China in Nature this week on a functional liver from stem cells and the threat posed by H7N9 virus

Stem cells: Building a new liver

Infectious disease: H7N9 reveals its dark side

The Nature journals press site is at

Stem cells: Building a new liver
DOI: 10.1038/nature12271

A functional human liver made using induced pluripotent stem cells is described in Nature this week. The liver is generated by transplanting liver buds (created in the laboratory) into mice, where the buds mature into tissue resembling the adult liver. Although it remains to be seen whether these techniques will work in human patients, the work provides a proof-of-concept that organ bud transplantation may represent a promising new approach towards regenerative medicine.

The critical shortage of donor organs for treating end-stage organ failure highlights the urgent need for obtaining organs by other means, such as generating them from induced pluripotent stem cells. Previous attempts to create complex vascularized organs from stem cells have been fraught with challenges, but Takanori Takebe, Hideki Taniguchi and colleagues take a new approach by focusing on the earliest stage of organ generation. They produce a liver bud, an early structure that is seen when livers form, by recreating cellular interactions that normally take place during bud development. After transplantation, the organ develops a vascular system and performs liver-specific functions.

These results highlight the therapeutic potential for using transplantation of organ buds grown from induced pluripotent stem cells for treating organ failure.

Takanori Takebe (Yokohama City University Graduate School of Medicine, Japan)
Tel: +81 45 787 2672; E-mail: [email protected]

Hideki Taniguchi (Yokohama City University Graduate School of Medicine, Japan)
Tel: +81 45 787 2660; E-mail: [email protected]

H7N9 reveals its dark side
DOI: 10.1038/nature12379

A suite of biological features suggests that the H7N9 influenza A virus poses a serious threat to humans. The data, reported in Nature this week, highlight the importance of undertaking intensive surveillance for this virus.

Unlike H5N1 and H1N1 influenza viruses, the H7N9 virus binds to avian and human receptors. It infects and replicates within cells of the human trachea and lungs, reaching even those cells at the furthermost tips of the respiratory tree. This dual receptor binding and high growth may make the H7N9 virus more likely to be transmitted from birds to humans, Yuelong Shu and colleagues report. However, the decreased ability of H7N9 to replicate in the trachea compared to the lungs may relate to its inefficient human-to-human transmission.

Most patients infected with the virus become severely ill. This study also shows that infected patients have unusually high levels of inflammatory and immune cells, referred to as a ‘cytokine storm’, which may contribute to symptom severity. The lack of evidence of pre-existing immunity in the population at large, and the fact that the current seasonal vaccine offers no protection are concerning, the authors note, although no efficient human-to-human transmission has occurred.

Yuelong Shu (China CDC, Beijing, China)
Tel: +86 10 5890 0850; E-mail: [email protected]

Published: 03 Jul 2013

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