Sun, Jul 23, 2017 | updated 10:34 PM IST

Can humans regenerate body parts like acorn worms?

Updated: Nov 29, 2016 11:52 IST      
Can humans regenerate body parts like acorn worms?

Washington D.C. [USA], Nov. 29 (ANI): Is it possible for humans to regrow an amputated arm or leg, or completely restore nervous system function after a spinal cord injury?

It might be possible one day, as a new study of one of our closest invertebrate relatives, the acorn worm, reveals that acorn worms can regrow every major body part, raising hopes for regeneration in humans.

Acorn worms burrow in the sand around coral reefs, but their ancestral relationship to chordates means they have a genetic makeup and body plan surprisingly similar to ours.

A study led by the University of Washington and published in the December issue of the journal Developmental Dynamics has shown that acorn worms can regrow every major body part -- including the head, nervous system and internal organs -- from nothing after being sliced in half. If scientists can unlock the genetic network responsible for this feat, they might be able to regrow limbs in humans through manipulating our own similar genetic heritage.

"We share thousands of genes with these animals, and we have many, if not all, of the same genes they are using to regenerate their body structures," said lead author Shawn Luttrell, a UW biology doctoral student based at Friday Harbor Laboratories.

"This could have implications for central nervous system regeneration in humans if we can figure out the mechanism the worms use to regenerate," he added.

The new study finds that when an acorn worm -- one of the few living species of hemichordates -- is cut in half, it regrows head or tail parts on each opposite end in perfect proportion to the existing half. Imagine if you cut a person in half at the waist, the bottom half would grow a new head and the top half would grow new legs.

After three or four days, the worms start growing a proboscis and mouth, and five to 10 days after being cut the heart and kidneys reappear. By day 15, the worms had regrown a completely new neural tube, the researchers showed. In humans, this corresponds to the spinal cord and brain.

After being cut, each half of the worm continues to thrive, and subsequent severings also produce vital, healthy worms once all of the body parts regrow.

"Regeneration gives animals or populations immortality," said senior author Billie Swalla, director of Friday Harbor Laboratories and a UW biology professor.

"Not only are the tissues regrown, but they are regrown exactly the same way and with the same proportions so that at the end of the process, you can't tell a regenerated animal from one that has never been cut," he added.

The researchers also analyzed the gene expression patterns of acorn worms as they regrew body parts, which is an important first step in understanding the mechanisms driving regeneration.

They suspect that a "master control" gene or set of genes is responsible for activating a pattern of genetic activity that promotes regrowth, because once regeneration begins, the same pattern unfolds in every worm. It's as if the cells are independently reading road signs that tell them how far the mouth should be from the gill slits, and in what proportion to other body parts and the original worm's size.

When these gene patterns are known, eventually tissue from a person with an amputation could be collected and the genes in those cells activated to go down a regeneration pathway. Then, a tissue graft could be placed on the end of a severed limb and the arm or leg could regrow to the right size, Swalla explained.

"I really think we as humans have the potential to regenerate, but something isn't allowing that to happen," Swalla said. "I believe humans have these same genes, and if we can figure out how to turn on these genes, we can regenerate."

Regeneration is common in many animal lineages, though among the vertebrates (which includes humans) it is most robust in amphibians and fish. Humans can regrow parts of organs and skin cells to some degree, but we have lost the ability to regenerate complete body parts.

Scientists suspect several reasons for this: Our immune systems -- in a frenzy to staunch bleeding or prevent infection -- might inhibit regeneration by creating impenetrable scar tissue over wounds, or perhaps our relatively large size compared with other animals might make regeneration too energy intensive. Replacing a limb might not be cost-effective, from an energy perspective, if we can adapt to using nine fingers instead of 10 or one arm instead of two.

The researchers are now trying to decipher which type of cells the worms are using to regenerate. They might be using stem cells to promote regrowth, or they could be reassigning cells to take on the task of regrowing tissue.

They also hope to activate genes to stimulate complete regeneration in animals that currently aren't able to regrow all tissues, such as zebrafish.(ANI)

Spitting out clues to 'ghost species' of ancient human

Updated: Jul 23, 2017 13:15 IST     

Washington D.C. [USA], Jul 23 (ANI): Ancient Africans may have engaged in a 'sexual rendezvous' with a 'ghost' species of archaic humans, according to a recent study.

Full Story >>

Water could propel satellites in future

Updated: Jul 22, 2017 15:55 IST     

New Delhi [India], July 22 (ANI): An Indian start-up foraying into space technology is coming up with a propulsion system for satellites known as Microwave Thruster, designed to run on water as fuel medium.

Full Story >>

3-D scanning complex objects with water

Updated: Jul 22, 2017 13:02 IST     

Washington D.C. [USA], Jul 22 (ANI): A team of computer scientists and engineers has brought next-gen 3-D scanning of complex objects closer to reality with the help of water.

Full Story >>

Now, a 'soft' robot that 'grows' like vine

Updated: Jul 21, 2017 12:33 IST     

Washington D.C. [USA], July 21 (ANI): A team of researchers has developed a robot that can navigate its environment by extending its reach.

Full Story >>

Our lifestyle choices turning Earth into 'plastic planet'

Updated: Jul 21, 2017 11:21 IST     

Washington D.C. [USA], Jul 21 (ANI): The 'Age of Plastic' is coming and if the pollution levels continue to rise, Earth will soon turn into a plastic planet.

Full Story >>

Washington D.C. [USA], Jul 21 (ANI): When it comes to decision-making, you may want to choose the wisdom of an ant over the folly of a grasshopper, according to a recent study.

Full Story >>

When Mars got photobombed by its moon Phobos

Updated: Jul 21, 2017 09:50 IST     

Washington D.C. [USA], Jul 21 (ANI): NASA's Hubble Space Telescope has captured Phobos, one of Mars' two moons, during its orbital trek around the Red Planet.

Full Story >>

New Delhi [India], July 20 (ANI): A team of Indian and French scientists have developed a touch sensitive material that enhances response rate by thousand times from existing materials.

Full Story >>

NASA's HERA XIII crew returns home to slumber

Updated: Jul 20, 2017 13:32 IST     

Washington D.C. [USA], Jul 20 (ANI): After 45 days in NASA's Human Exploration Research Analog (HERA), the four-man crew can hardly hold their eyes open.

Full Story >>

Washington D.C. [USA], Jul 20 (ANI): Until recently, invisibility cloaks and the like were firmly in the realms of science fiction, but now, you may soon be able to live out your wildest Harry Potter dreams.

Full Story >>

A secret to Elastigirl's powers: Magnets

Updated: Jul 20, 2017 10:39 IST     

Washington D.C. [USA], Jul 20 (ANI): If Plastic Man, Elastigirl and Mr Fantastic were to take up arms against Magneto, they'd be at a serious disadvantage, according to the latest research from Christian Binek.

Full Story >>

This is your brain on meditation

Updated: Jul 14, 2017 19:19 IST     

Oslo [Norway], Jul 14 (ANI): A team of researchers has shed some light on how meditation actually affects your brain.

Full Story >>

New Delhi [India], July 14 (ANI): Climate change is one of the biggest crises facing humanity

Full Story >>

Trouble reading smaller font? Turn to visual illusion

Updated: Jul 13, 2017 10:28 IST     

Washington D.C. [USA], Jul 13 (ANI): A recent study has found that exposure to a common visual illusion may enhance your ability to read fine print.

Full Story >>

Soon, watch 3-D movies at home sans glasses

Updated: Jul 13, 2017 10:27 IST     

Washington D.C. [USA], Jul 13 (ANI): A team of researchers is trying to bring glasses-free 3-D technology to your living room.

Full Story >>

A 'larger-than-Earth' sunspot is turning toward us

Updated: Jul 13, 2017 09:52 IST     

Washington D.C. [USA], Jul 13 (ANI): NASA's Solar Dynamics Observatory (SDO) has detected a massive sunspot, called Active Region 2665, that's bigger than Earth.

Full Story >>

When NASA's Juno stared right into Jupiter's angry red eye

Updated: Jul 13, 2017 09:26 IST     

Washington D.C. [USA], Jul 13 (ANI): The first ever close-up images of Jupiter's gargantuan hurricane, the Great Red Spot, have been revealed from NASA's Juno spacecraft after it completed its historic fly-by a few days ago.

Full Story >>

Antarctica just lost a 'Delaware-sized' iceberg!

Updated: Jul 13, 2017 07:49 IST     

Washington D.C. [USA], Jul 13 (ANI): A massive iceberg about the size of the state of Delaware split off from Antarctica's Larsen C ice shelf sometime between July 10 and July 12.

Full Story >>

London [UK], July 10 (ANI): Google Doodle, today, celebrates Swedish scientist Eva Ekeblad 293rd birthday.

Full Story >>

A urine test can predict recurrence of cancer

Updated: Jul 09, 2017 14:55 IST     

Washington D.C. [USA], July 9 (ANI): A team of researchers have developed a simple urine test to more accurately predict the recurrence of bladder cancer.

Full Story >>