BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: regeneration

Zebrafish: The Cure to Vision Loss?

Sight is one way in which we, along with many animals, interact with the world. Unfortunately, some people are unable to interact with the world in that same manner. Whether it is hereditary blindness or vision loss due to a neurodegenerative disease, vision loss and eye damage is difficult to fix, especially at a neurological level.

Neurons are present throughout the body and are connected via the nervous system. Their function is to transmit information to the brain and the rest of the body. They do this by signaling other cells by what is called neuronal firing. Individual nerve cells send electrical impulses to others allowing the message to reach other parts of the body. Simply put in the case of eyes and sight, the lens collect and bend the light and that information is sent through the optic nerve to the brain which then processes the information to produce an image. Therefore, if the neurons in the eye are damaged, that information cannot be collected and sent to the brain.

One such eye problem is Macular Degeneration which targets the macula. The macula is the central part of the retina that collects details images from the center of one’s field of vision. Damage to the macula results in a loss of central vision. Those who have it still retain their peripheral vision, but if the case is severe enough, they are deemed legally blind. As of now, there is no known cure.

However, Johns Hopkins Medicine researchers have been studying some animals’ ability to regrow neurons. Fish, along with other cold-blooded animals have the ability to repair eye neurons after injury, and for a long time it was thought that these genes were not present in mammals. According to Seth Blackshaw, professor of neuroscience at John Hopkins University, “[there is] the potential for regeneration is there in mammals, including humans, but some evolutionary pressure has turned it off” (ScienceDaily.com).

Blackshaw’s team has been studying the supportive cells in the back of the eye in zebrafish. These cells, known as the Müller glia, are able to repair the retina by growing neurons. Blackshaw’s team examined the retinal damage and repair of zebrafish, chickens, and mice. They found that while chicken and mice both have the capacity and gene pathways to generate neurons, the transcription factors were blocked so that the neurons don’t regenerate. Blackshaw suspects that the inability to regenerate neurons is due to the fact that animals that are more prone to disease in the brain, or other neurological tissue, may have lost this regenerative ability in order to protect other brain cells.

All of this is very exciting news and I think it is fascinating that studying cells from a fish could potentially help people who suffer from vision loss. I never would have thought that an animal that seems so different from us could help solve a problem that people have been dealing with for centuries. However, I think it is the fact that perhaps we aren’t so different from animals, at least on a biological level, that we are able to study them in order to better understand ourselves. For example, as Blackshaw and his team has discovered, we have those same gene pathways that allow zebrafish to regenerate neurons. And while ours don’t work the same way as of now, they are still present despite years and years of evolution. In the end, I think that the similarities we share with other animals is something to think about.

Bioelectronic Medicine is Moving Fast, Artificial Nerve Regeneration to the Rescue!

 

Researchers at both Washington University School of Medicine and Northwestern have just made a discovery that has huge potential for future patients of nerve damage. Diseases such as Alzheimer’s, Bell’s palsy, Cerebral palsy, and many other illnesses regarding the nervous system/ nerves are one step closer to having a cure! Beyond chemistry and drugs, scientists are now using technology to find a cure using the first ever development of bioelectronic medicine. A device, ” The size of a dime and the thickness of a sheet of paper,” is implanted in the body to “speed nerve regeneration and improve the healing of a damaged nerve”.

This device, which is currently nameless, is powered wirelessly by a “transmitter outside the body that acts much like a cellphone-charging mat”. It is very thin and works by winding around a directly injured nerve(precisely where needed). After the device has engulfed the injured nerves, it delivers electrical pulses. These pulses accelerate wound healing and reproduce nerves. Doctors/ patients using this device have the ability to control the times which pulses are sent. Around two weeks after the device is injected, it naturally absorbs into the body not harmfully.

Image result for nerves

The device has yet to be tested on humans. Recent discoveries have been based on observations on rats with injured sciatic nerves. These nerves in rats send signals throughout the legs to control muscles in feet and legs as well as hamstring muscles. To perform the study, scientist spent ten weeks monitoring rats’ recovery while providing pulses one hour per day for one, three, six, or no days at all a week. After a little more than three months, researchers concluded that “any electrical stimulation was better than none at all at helping the rats recover muscle mass and muscle strength”, and the device accelerated the regrowth of nerves. They also concluded that “the more days of electrical stimulation the rats received, the more quickly and thoroughly they recovered nerve signaling and muscle strength”. Overall, no side effects of the device and its reabsorption were found.

Overall, this discovery can do great things for the human population. Making it extremely convenient, this device after put on can possibly replace pharmaceutical treatments for a variety of medical conditions in humans

Researchers are currently continuing to study this device to see what is most effective in animals similar to humans. They are evaluating the effectiveness of the devices different sizes,  duration, and fabrication.

Just Keep Swimming…and Fixing Paralysis!

 

Zebrafish (Danio rerio)

Zebrafish (Danio rerio)- from Flickr

The zebrafish may just look like a cute aquatic animal, but they actually have a unique power that humans don’t: they can heal a severed spinal cord. While this uncanny ability sounds almost magical, it can be explained by the work of a certain protein, CTGF (connective tissue growth factor), that humans have as well. Because of this commonality, recent research conducted by Duke University suggests that by learning from the mechanism that allows the Zebrafish to do this, humans may eventually be able to regenerate their lost spinal tissue!

Essentially, the zebrafish is able to regenerate their spinal cord by forming a cellular bridge across the damaged or missing area. They can be fully healed in as little as 8 weeks! But how is this “bridge” possible on a molecular level? When the fish get injured, dozens of genes get activated. Seven of these genes code for proteins that are secreted from cells. The researchers at Duke found that CTGF, one of these proteins, is crucial to the bridge-making process. They found this by looking at the glia, which are the supporting cells that help initially form the bridge before the arrival of nerve cells. After forming the bridge, CTGF levels rose marginally in these glia. When the researchers genetically deleted CTGF from the glia, the whole regeneration process failed. This research proved exciting because humans also have a very similar form of CTGF, and when they added this human-version of the gene to the glia, regeneration was even faster, only taking 2 weeks! The researchers even discovered which of the four parts of CTGF was the important one in this regeneration phenomenon, which in the future would make it easier to create therapies modeled after this part for humans.

However, using this knowledge to help human tissue regeneration is not as straightforward as it may seem. Mammals such as ourselves form scar tissue around damaged areas, complicating the matter further. The group plans on experimenting with other mammals, namely mice to compare and contrast their CTGF levels with those of zebrafish. Do you think that CTGF research is the best way to achieve human tissue regeneration? Is there any way to prevent scar tissue from forming around our wounds? Let me know in the comments!

 

Original Article: https://www.sciencedaily.com/releases/2016/11/161103142321.htm

Photo Credit to Tohru Murakami: https://flic.kr/p/nb2gGH

New Stem Cell Discovered in Brain

Credit Isaac Mao, http://www.flickr.com/photos/isaacmao/544928/

At Lund University, researchers have discovered a brand new type of stem cell in the adult human brain, which is thought to be responsible for the regeneration of muscle, bone, cartilage, and adipose tissue.

Stem cells are known for their ability to proliferate into several different cell types, providing a plethora of research opportunities for medical researchers.  These specific stem cells, found near small blood vessels in the brain through the analysis of brain tissue from biopsies, have also been identified in other locations of the body.  In other organs, the stem cell appears to have a similar structure, and is responsible for repair and wound healing, leading scientists to suggest that the curative properties may also apply to the brain.

The next step is to better understand this new type of stem cell, and to learn how to better control and enhance its self-healing properties.  “Our findings show that the cell capacity is much larger than we originally thought, and that these cells are very versatile,” said Gesine Paul-Visse, Ph.D., Associate Professor of Neuroscience at Lund University.

With a more thorough understanding of how this stem cell operates, researchers hope to use it to better treat neurodegenerative diseases and stroke.

As Paul-Visse puts it, “Ultimately the goal is to strengthen these mechanisms and develop new treatments that can repair the diseased brain.”

For more information, read the article “New stem cell found in the brain” http://www.biologynews.net/archives/2012/04/23/new_stem_cell_found_in_the_brain.html

Or look for the original study published in the journal PLos ONE.

So, what do you think?  Will this new stem cell found in the brain make an important impact in neurobiological research?

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