In the image above, a novel type of human stem cell is shown in green integrating and developing into the surrounding cells of a nonviable mouse embryo. Red indicates cells of endoderm lineage. Endoderm cells can give rise to tissue that covers organs from the digestive and respiratory systems. The new stem cell, developed at the Salk Institute, holds promise for one day growing replacement functional cells and tissues. 

Scientists at the Salk Institute in California, have discovered a new type of Stem Cell that is pluripotent and can potentially mature into functional tissues. In contrast with conventional human stem cells, the newly developed cells, are spatially oriented and obtain an identity that is linked to their location or position in the embryo. The newly discovered cells known as Region Selective Pluripotent Stem Cells or rsPSCs in short, are easier to grow in a laboratory setting and offer several advantages for large scale production. This makes them more suited for Tissue Engineering than their conventional counterparts.

LABORATÓRIO 5In order to create these novel stem cells, the scientists in Salk Institute developed a sequence of chemical signals that directed the spatial orientation of the conventional Human Stem Cells thereby acting as a cue to develop into rsPSCs. The newly created spatially oriented cells were inserted into partially dissected mouse embryos and cultured over a period of 36 hours. Conventional stem cells were also subjected to the same treatment as their spatially oriented counterparts.

It was observed that the spatially oriented rsPSC’s fared better than the conventionally derived human stem cells. While the conventionally derived cells did not integrate into the modified mouse embryo’s, the rsPSC’s began to develop into early stage tissue by differentiating to the three major germ layers namely the ectoderm, endoderm and mesoderm. These three germ layers are capable of differentiating into several tissues, wherein the type of tissue depends on the germ layer it originates from. (e.g.. Peripheral nervous system originates from the ectoderm and the stomach evolves from the endodermal cells). The scientists at Salk however, stopped the germ layers from differentiating and developing into mature tissues.

This presents a novel breakthrough in the fields of regenerative medicine and tissue engineering. Understanding the time and space parameters of these cells will aid in the generation of functional tissues for regenerative medicine. Theoretically the rsPSCs are capable of maturing into any functional tissue and this may make regenerative medicine a more viable option for tissue replacement in the future.

* AN ALTERNATIVE PLURIPOTENT STATE CONFERS INTERSPECIES CHIMAERIC COMPETENCY, Jun Wu, Daiji Okamura, Mo Li, Keiichiro Suzuki, Chongyuan Luo, Li Ma, Yupeng He, Zhongwei Li, Chris Benner, Isao Tamura, Marie N. Krause, Joseph R. Nery, Tingting Du, Zhuzhu Zhang, Tomoaki Hishida, Yuta Takahashi, Emi Aizawa, Na Young Kim, Jeronimo Lajara, Pedro Guillen, Josep M. Campistol, Concepcion Rodriguez Esteban, Pablo J. Ross, Alan Saghatelian, Bing Ren et al. Nature 521, 316–321 (21 May 2015) doi:10.1038/nature14413