Transplanted Embryonic Nerve Cells can Integrate with the Adult Brain

In what seems like an important proof of concept, researchers here demonstrate that transplanted embryonic neurons can integrate fully into an adult brain, and carry out the same functions as existing adult cells. This means that suitable forms of reprogrammed neural cells, such as those derived from induced pluripotent stem cells, should be just as capable. This sort of result reinforces the need to continue the development of cell therapies for the aging brain, intended to replace lost cells and reinforce failing functionality. Lost cells are only one part of the overall problem, as there is the age-damaged cellular environment to repair as well, but in a number of neurodegenerative conditions cell loss is a very significant proximate cause of pathology. Parkinson's disease, for example, involves the loss of the small population of neurons that produce dopamine.

When it comes to recovering from insult, the adult human brain has very little ability to compensate for nerve-cell loss. Biomedical researchers and clinicians are therefore exploring the possibility of using transplanted nerve cells to replace neurons that have been irreparably damaged as a result of trauma or disease. Previous studies have suggested there is potential to remedy at least some of the clinical symptoms resulting from acquired brain disease through the transplantation of fetal nerve cells into damaged neuronal networks. However, it is not clear whether transplanted intact neurons can be sufficiently integrated to result in restored function of the lesioned network. Now researchers have demonstrated that, in mice, transplanted embryonic nerve cells can indeed be incorporated into an existing network in such a way that they correctly carry out the tasks performed by the damaged cells originally found in that position. Such work is of importance in the potential treatment of all acquired brain disease including neurodegenerative illnesses such as Alzheimer's or Parkinson's disease, as well as strokes and trauma, given each disease state leads to the large-scale, irreversible loss of nerve cells and the acquisition of a what is usually a lifelong neurological deficit for the affected person.

The researchers specifically asked whether transplanted embryonic nerve cells can functionally integrate into the visual cortex of adult mice. "This region of the brain is ideal for such experiments. We know so much about the functions of the nerve cells in this region and the connections between them that we can readily assess whether the implanted nerve cells actually perform the tasks normally carried out by the network." In their experiments, the team transplanted embryonic nerve cells from the cerebral cortex into lesioned areas of the visual cortex of adult mice. Over the course of the following weeks and months, they monitored the behavior of the implanted, immature neurons by means of two-photon microscopy to ascertain whether they differentiated into so-called pyramidal cells, a cell type normally found in the area of interest. "The very fact that the cells survived and continued to develop was very encouraging. But things got really exciting when we took a closer look at the electrical activity of the transplanted cells." The researchers were able to show that the new cells formed the synaptic connections that neurons in their position in the network would normally make, and that they responded to visual stimuli. The team then went on to characterize, for the first time, the broader pattern of connections made by the transplanted neurons. They found that pyramidal cells derived from the transplanted immature neurons formed functional connections with the appropriate nerve cells all over the brain. In other words, they received precisely the same inputs as their predecessors in the network. In addition, they were able to process that information and pass it on to the downstream neurons which had also differentiated in the correct manner.

Link: http://www.en.uni-muenchen.de/news/newsarchiv/2016/goetz_neuenerven.html

Comments

Reason, is there any recent research that you know of that is trying to create truly "young" IPS cells? It seems that this is something that would be needed to create robust SENS type rejuvenation. I imagine that it must be possible to do somehow from the germ line cells in an adult body.

Posted by: Link at November 8th, 2016 7:45 AM

@Link: Everything I've seen on that topic is largely investigative. Researchers are still quantifying possible differences between young cells and iPS cells derived from older tissues. Of which there seem to be a fair number, depending on methodology. There are studies showing epigenetic patterns remaining after programming, studies investigating the details of mitochondrial rejuvenation, ever deeper comparisons with embryonic stem cells, etc, etc. Lots of somewhat contradictory results. All pretty early to be doing anything with it in a deterministic rather than opportunistic way.

Then of course there is the nuclear DNA damage, which reprogramming isn't going to touch. That's a whole other line item.

Posted by: Reason at November 8th, 2016 4:59 PM
Comment Submission

Post a comment; thoughtful, considered opinions are valued. New comments can be edited for a few minutes following submission. Comments incorporating ad hominem attacks, advertising, and other forms of inappropriate behavior are likely to be deleted.

Note that there is a comment feed for those who like to keep up with conversations.