The Holy Grail of regrowing human body parts could well be within our reach, since a significant discovery in the science of stem cell research has been identified by experts. Scientists have found a single stem cell that is able to regenerate an entire organism, and is the cause of the planarian flatworm to regenerate its head along with its brain and other bodily tissues.
This is considered a major scientific breakthrough that has amazing potential for research in the pursuit of human regeneration.
A century in the making and researchers have observed the incredible effects of this cellular phenomenon which give certain lifeforms like the planarian flatworm to perform regenerative feats such as regrowing a lost head. However, until now, they did not have the technological tools that would allow them to track the cell in question and observe its secrets.
In 2015, I wrote about regrowing lost limbs and body parts surrounding the studies done on planarian worm regeneration. I recommended reading since this new article is a follow up to that previous article.
Originally, I focused on the planarian flatworm as I realized its importance in regeneration that would one day help humans. It reveals the research that scientists were doing into the flatworm and that some experts feel that the creature holds the key to immortality.
The dream of regenerative medicine is where cells of the skin and even whole organs and limbs can be regrown, along with one day provide medical cures for a number of conditions, such as diabetes, cancer and heart disease.
Now scientists from the Stowers Institute for Medical Research in Kansas City, Missouri, have discovered the cell which can reproduce the entire organism. This has been achieved by a method of combining genomics, single-cell analysis, flow-cytometry that scans the cells in a fast-flowing river of blood.
Stem Cell Research
The initial step is to isolate this astonishing cell in the planarian flatworm before it starts to carry out its remarkable regenerative role.
The stem cell discovered by researchers has been named Nb2 and is a kind of adult pluripotent stem cell. This is an unspecialized “master” cell that exists in humans and will develop into different types of organs and tissues. However, what is significant about the Nb2 stem cell, it was tracked using a biological signature that is present in humans with a protein known as piwi-1.
One of the molecular biologists involved in this research, Professor Alejandro Sanchez Alvarado explained that this is the first occurrence an adult pluripotent stem cell has been observed.
An article published on their website at Stowers Institute about this research, the Professor points out:
“Our finding essentially says that this is no longer an abstraction, that there truly is a cellular entity that can restore regenerative capacities to animals that have lost it and that such entity can now be purified alive and studied in detail.”
Sanchez Alvarado commented further by saying:
“The fact the marker we discovered is expressed not only in planarians but also in humans suggests there are some conserved mechanisms that we can exploit… I expect those first principles will be broadly applicable to any organism that ever relied on stem cells to become what they are today. And that essentially is everybody.”– Sanchez Alvarado
How Well Do Species Regenerate?
All lifeforms, including humans, are able to regenerate. The question is of how much can you do this and with humans, it is more limited. Invertebrates like the starfish and earth worm, regeneration is much more a developed process.
Such creatures are able to regrow a new tail, a head and a tonne of other body parts when they get damaged or lost.
It has always been a mystery and elusive why mammals (including humans) have limited regenerative abilities but certainly, we are able to regrow skin, blood, and tissues. In fact, our liver is able to regenerate up to a point which makes sense for the kind of important role this organ has.
An organism is developed from a single cell. This single cell divides into two, four, eight identical cells and on it goes. Now each of these cells is identical holding the same stands of DNA and thus pluripotent, the potential and possibility to give rise to all types of cells in the body.
However, along the journey the initial starter cells that are called embryonic stem cells, allow themselves to take a different path and turn out to be heart cells, skin cells, and other cell types.
After birth, pluripotent stem cells do not exist after the baby is born. But in the planarian flatworm, these cell types will stay put into the adult years and are called neoblasts of adult pluripotent stem cells.
Researchers specializing in this area feel that these neoblasts hold the ticket to regeneration.
The study of neoblasts is nothing new and goes back to the later 1800s. However, in the past 20 years, improved molecular techniques have shown that there exists a number of varieties that contain different patterns of gene expression.
The scientists in this new research on identifying the stem cell explained that they might have to end up transplanting 100+ individual cells into an even greater number of worms with the aim to identify a flatworm that is genuinely pluripotent and therefore able to regenerate.
As you can imagine that is a large amount of effort just to detect one cell that fits the characteristics of the neoblast that you are looking for.
Furthermore, in order to find out the genes that a particular cell is expressing, you would have to destroy that cell for study.
So how do you maintain the cell and keep it alive while monitoring it during its regenerative journey?
Detecting Qualified Neoblasts
A technique that has long been in the works to tell neoblast from other cell types is using the piwi-1 protein. So the team decided to separate those cells that expressed piwi-1 from those that didn’t have it. This resulted in cells that would only qualify to be neoblasts, if they possessed high in the protein.
Professor Sanchez Alvarado added:
‘This kind of simultaneous quantitative analysis of gene expression and protein levels had never been done before in planarians… researchers had assumed that all cells expressing piwi-1 were true neoblasts, and it didn’t matter how much of the marker they expressed. We showed it did matter.”
So the researchers went through an elimination process of eight thousand cells that were rich in the piwi-1 protein, allowing them to rule out any that would end up for a particular purpose such as skin. muscle or other tissues.
In the end, they were left with two cell types that might be pluripotent and the scientists named these Nb1 and Nb2.
The researchers discovered the Nb2 expressed a group of proteins that are not well understood and these sit on the outer layer of the cells.
Dr An Zeng, a co-author working with Professor Sanchez Alvarado, created an antibody that was intended to ‘clamp’ onto the cell, pulling the cells that had the antibody out of a cocktail of suspected neoblasts.
A planarian flatworm had been subjected to extremely high levels of radiation. Zeng would then placed this ‘single purified cell’ into the planarian.
These cells repopulated and healed the irradiated creatures and did so fourteen times more efficiently than cells purified by older techniques.
The scientists noted that they had enriched for a pluripotent stem cell population and this paves the way to new kinds of experiments that were not possible previously.
In the previous article that I had written about planarian worm regeneration, I mentioned that studies had shown that the flatworm could live forever after scientists examined their ability to regenerate indefinitely.
In fact, I also mentioned that researchers had observed if you cut the planarians up into little parts. Those little pieces of flatworm would then regenerate into a completely new worm. The scientist concluded it can help develop new breakthrough medicines that can allow humans to stay looking youthful for longer as people age.
This article is a nice follow up to the blog post that I originally wrote back in September 2015 about the planarian flatworm and highlighting the advances that have been made.
The amazing god-like powers of the freshwater flatworm that is known as the planaria, is one of the favorite candidates for scientists who research into human regeneration.
It is hoped that by unlocking the mysteries of this creature will give powerful answers in how its regenerative powers can be harnessed in humans. It was roughly over a century ago that scientists were able to trace the flatworm’s powers of regeneration to a particular family of adult stem cells known as neoblasts.
However, until recent advancements in technology, it was not possible to focus specifically on the actual cells truly capable of regeneration. By identifying a specific cell that can regenerate an entire organism, it has important implications in regrowing human body parts and advancing the field of stem cell biology and regenerative medicine.
The scientists’ findings were published in the Journal Cell Magazine. How do you feel about this article? Let me know your opinions about this research or if you have any questions. I think it is extremely existing that scientists are making headway with how the planarian flatworm regenerates and the prospects of applying this to humans.
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