Scientists are looking for ways to regenerate human body tissue in the intestinal genes

All stages of intestinal worm regeneration

What would happen if people could grow amputated limbs or completely restore the function of the nervous system after a spinal cord injury? A new study of the invertebrate intestinal showed that one day it may become a reality.

Presumably, intestinal worms are the closest relatives of chordates . Some scientists believe that chordates originate from intestinal breathing and consider the latter as the “missing link” between invertebrates and vertebrates. The genetic structure and body structure of these worms are surprisingly similar to human ones.
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Research from Washington University showed that intestinal worms can grow all the main parts of the body, including the head, nervous system, and internal organs out of nothing, after they have been cut in half. If scientists find the genes responsible for this mechanism, then they will be able to re-grow human limbs through the management of a similar genome.

“We share thousands of genes with these animals, and we have many, if not all, of the same genes that are used to restore body structure. This may have implications for the regeneration of the central nervous system in the human body if we can determine the mechanism that the worms use to create new organs and tissues, ”said study lead author Shawn Luttrell.


Intact worm body. His head is on the left side, the worm is cut in the middle.

A new study showed that when the intestinal cavity, one of the few surviving semi - chordal species, is cut in half, it regenerates parts of the head or tail at each opposite end in perfect proportions to the existing half. Imagine if you cut a person in half, the lower half will grow a new head, and the upper half - legs.


The lower half of the worm's body after cutting. The frame marks the zone from which the worm will grow a new head.

After three or four days, the worms begin to grow proboscis and mouth, it takes five to ten days to grow the heart and kidneys.


5 days after cutting. Slice shot close up. A rudimentary head and oral cavity with a proboscis were formed.

On day 15, the worms grow a completely new neural tube, which in function corresponds to the human spinal cord. After the worm has restored all the functions of the body, it continues its full existence and can produce healthy offspring.


Close-up cut after 15 days. A more developed head and neural tube is formed, the nervous system and organs functions are restored.

The team of biologists is confident that regeneration gives individual animals and populations immortality. Their tissues are not just regenerated, they are regenerated in the same proportions. After the intestinal breathing grows itself any part of the body, they can no longer be distinguished from those individuals who have never had to do this.

Researchers also analyzed gene expression after worms raised new body parts. This is the first important step for understanding the mechanisms that govern regeneration. They suspect that the “central control panel of regeneration” is a gene or a set of genes responsible for activating the pattern of genetic activity. The mechanism works in such a way as if the cells independently read the instructions, how far the mouth opening should be from the gill slits and in what proportion relative to other parts of the body.

When the structure of these genes becomes known, it will be possible to collect samples of human tissues that underwent amputation, and activate the genes in the cells of these tissues for regeneration. Then, the researchers argue, it is enough to place the tissue graft on the cut of a lost limb, and then it will grow to the desired size.

Scientists believe that people have the potential for regeneration, but something does not allow it to occur. Billie Swalla, director of Friday Harbor Laboratories, believes that people have the same genes that cause tissue to recover. You just need to understand how to activate them.

Regeneration is common among a variety of animal species. Among vertebrates, it is most strongly developed in amphibians and fish. A person is able to restore to some extent parts of the organs and cells of the skin, but he has lost the ability to fully regenerate lost parts of the body. Scientists suspect that there are several reasons.

Our immune system in trying to stop the bleeding or prevent infection can inhibit regeneration, forming scar tissue on wounds. Or the size of a person too large compared to other animals makes regeneration too energy-consuming. Replacing a limb cannot be effective in terms of the energy it consumes, if we can adapt to using nine fingers instead of ten or one hand instead of two.

Now a team of scientists is trying to figure out what type of cell the worms use for regeneration. Researchers suggest that it could be stem cells that promote tissue repair, or other types of cells that can be reoriented to the resumption of limb growth. They also hope to activate genes in order to stimulate full regeneration in animals that now cannot fully restore all tissues.

Scientific work published in the journal Developmental Dynamics October 25, 2016
DOI: 10.1002 / dvdy.24457