BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: Itch

Have We Discovered The Itchy Stitch?

A Brand New Poison Ivy Vaccine is in the Works; here is What We Know So Far.

Vaccine: The word spoken and heard by most Americans at least ten times daily this past year, yet not usually preceded by “Poison Ivy.” Working at Duke University, biochemist Sven- Eric Jordt heads a team of researchers investigating pain and itch mechanisms, studying the unpleasant sensations of Toxicodendron radicans, better known as poison ivy. Jordt reveals that contact dermatitis (the red rash received from poison ivy) is usually treated by local doctors and rarely shown attention or mass funding. Author of ‘A Vaccine Against Poison Ivy Misery Is In The Works,’ Claudia Wells states, “given the toll in suffering and dollars, you would think serious attention would be paid to this worsening public health issue, you’d be wrong.” When pharmaceutical companies recognized more money was to be made on drugs for chronic skin conditions like eczema, they felt no need to research effective treatments on a temporary rash.  

Toxicodendron radicans (poison ivy) 2 (49046043216)

Having never personally contracted poison ivy, I cannot describe the exact feelings of pain or irritation, but to quote a good friend, “it would be less painful for my skin to be set on fire.” Now I must state that this friend did have an extreme reaction to poison ivy, they pitched their tent in a field of the poisonous plant, yet severe reactions are more common than most might assume. Every year 10 – 50 million Americans contract poison ivy and suffer for an average of 2-3 weeks. Research obtained in a six-year study at Duke University found that an increase of carbon dioxide, i.e., climate change, causes the poison ivy plant to produce a more potent allergenic form of Urushiol, the resin responsible for the rash. With increased concerns regarding climate change, it appears odd that Jordt is one of few who take this rash seriously.

 Currently, the main treatment methods of antihistamines and cortisone cream do the rash very little justice. This is because our body’s reaction to Urushiol has no relationship to histamines, rendering antihistamines useless. In explaining this information to my dad, he agreed that all of the efforts recommended to him when he got poison ivy, a little less than two years ago, proved ineffective. To solve this, Sven Jordt and his colleagues began to analyze receptors that matched with proteins that showed inflammation from Urushiol.

In biology, receptors are proteins that receive signals by bonding with molecules known as ligands to send a specific message onward. A cell’s response depends on the types of receptors present, and each cell has its own number and type of receptor that allows them to act differently to various stimuli. Regarding poison ivy, Jordt and his team discovered that interleukin 33, an immune chemical in the body, is the main culprit behind the symptom of itchy skin. Jordt and his team of researchers are currently testing antibodies against IL-33, such as ST2, in primary sensory neurons. If ST2 could effectively block IL-33’s receptors, the necessity to scratch would virtually disappear. “This is all very new information,” Dermatologist Brain Kim, co-director of the Center for the Study of Itch & Sensory Disorders at Washington University in St. Louis, states. In the past, scientists believed that both the rash and itch from poison ivy were triggered by the immune system’s T cells. Further studies, however, have shown that the inflamed rash and itch sensation come from two different places entirely; It is believed “T cells do cause the inflamed rash of poison ivy but that these other pathways provoke the itch.” (Brian Kim)

 While human research has been challenging to complete due to a lack of study funding, a compound called PDC-APB, a small synthetic molecule derived from active urushiol components, is being developed into a vaccine to prevent painful contact dermatitis.

 As stated earlier, I have thankfully never had poison ivy myself, and I would like to keep it that way. As someone who goes on Sunday hikes through the woods with my family, contracting poison ivy is a constant fear of mine and leaves me wearing pants while walking in the July heat. I think a vaccine would be a fantastic option for someone who spends much of their time in places of possible poison ivy. The only question would be, is this the solution to our itchy problem?

 

WP20Symbols vaccine

IS THAT POISON IVY???

Scientists have discovered a possible new treatment to prevent itching from poison ivy, a painful nuisance that affects up to 50 million Americans annually. Using an antibody for the protein interleukin-33, scientists were able to drastically reduce itching in test mice. As treatment now generally doesn’t do much to combat the discomfort of itching, this is a major breakthrough in poison ivy treatment.

What is Poison Ivy?

 Poison Ivy is a plant that produces resinous oil called urushiol that covers the entire plant: stems, leaves, and roots. When this oil comes into contact with human skin, either directly or through a secondary source like an animal or tool, it triggers an allergic reaction in 85% of people, causing your immune system to attack and create an itchy rash. This rash can escalate into hives and blisters.

What is this discovery?

So far there is treatment such as antihistamines and corticosteroids that help swelling, pain and accelerate recovery, but there is no real cure for the itchiness and discomfort this rash can cause. However, by blocking a certain protein in the immune system with an antibody, one can block the signals to the brain communicating an itch on the skin. This protein is interleukin 33 (IL-33), a common protein that acts directly on the nerve fibers in the skin, exciting them and telling the brain that the skin is severely itchy. When blocking this protein, scientists conducting an experiment on lab mice were able to reduce not only inflammation, but the amount of scratching.

What does this mean?

If this treatment could be used on humans, it would provide a far more affordable and effective treatment for victims of this pesky condition, and eliminate the doctors visits, lost time at work or school, and costs of only partly helpful drugs that are now necessary for people suffering from this rash. Hopefully, the pain and annoyance that comes with Poison Ivy will soon be a thing of the past.

Image: https://commons.wikimedia.org/wiki/File:Poison_ivy-20141524-038.jpg

The Difference Between Itching and Pain

A new scientific breakthrough has led researchers to conclude that the feelings of itching and pain are relayed to the brain by different nerve cells. It was previously thought sensory nerve cells on the skin perceived both itching and pain. However, recent debate over this subject prompted a group of scientists at Johns Hopkins University to get to the bottom of it. In their experiments the scientists observed the reactions of mice to certain stimuli under different conditions. In the first experiment, the scientists isolated a type of nerve cell called MrgA3 by coating it with a glowing protein. They then exposed the mice to both pain and itch inducing stimuli, and found that MrgA3 sent a signal for both conditions. In another experiment, the researchers purposefully killed the MrgA3 cells so that they could observe how the mice responded to the same stimuli without them. They found that the mice acted in a similar way, albeit a stronger itching sensation was required to garner reactions similar in magnitude. This proved that there are other types of sensory nerve cells that are able to sense and relay the feeling of itchiness. In a final experiment, the scientists made it so that the MrgA3 cells were the only ones able to respond to a specific type of painful stimuli. After exposing the mice to the specific type of pain and to an itchy sensation, they found that in both cases the mice itched in response. This proved that MrgA3 nerve cells interpret both itchiness and pain as itchiness. This could potentially be very important to people who develop a chronic itch due to certain medications, or people with a phantom itch. Now that scientists know that only certain sensory nerve cells send the signal of itchiness to the brain, they may be able to shut them down when a patient has developed a chronic or phantom itch. Perhaps they will even come up with a way to stop the itch caused by wool sweaters, so during the next holiday season you won’t constantly be scratching when your mom forces you to wear one.

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