The top three news stories of the week, as chosen by our resident students. This week’s top stories are micromachine infection fighters, erasing fear and treating peanut allergies.
By Brooke Lumicisi.
The rise of the micromachines
A group of nanoengineers at the University of California San Diego have developed a sophisticated micromotor system to treat ulcers created by a bacterial infection in the stomach.
It was in 2005 that the Nobel Prize was awarded to Dr’s Marshal and Warren for their discovery that stomach ulcers were caused by a bacterial infection of Helicobacter pylori. Since then doctors have been treating stomach ulcers with antibiotics. However, in order to do so the patients must take additional drugs known as proton pump inhibitors to suppress gastric acid production which can damage the antibiotics before they are able to do their work. These inhibitors can cause nasty side effects if taken in high doses or for long periods. This led the group from UC San Diego led by Professors Wang and Zhang to investigate alternative methods of delivering the antibiotics and modulating the stomach environment.
The mini machines were given to mice with Helicobacter pylori infections. These little vehicles are carrying a cargo of antibiotic covered by a layer of another protein that helps it bind to the stomach wall. The cargo is carried by a micromotor which uses the stomach’s own acid to generate a stream of microbubbles, propelling the complex around the stomach, reducing the acidity as it goes. Once the pH (the measure of acidity) has reached optimal levels the motor releases the antibiotic to go to work on the bacteria.
The micromotor method was found to be at least as good at treating the infection as the dual antibiotic/proton pump method, and the stomach acidity returned to normal within 24 hours.
A research group from the University of California has used optogenetics to weaken connections between specific neurons in mice and eradicate fear of a particular noise.
Woong Bin Kim and Jun-Heyeong Cho conditioned the mice to be fearful of a high pitched noise by shocking the mice after playing the noise. They then examined the areas in the brain that were activated when the noise was played, compared to a control noise where no shock was given. After determining the neural connections activated by the noise associated with the shocks, they saw that the connections between these neurons actually diminished if they played the noise repeatedly over time without giving the shocks, a process known as fear extinction. Fear extinction is the basis of ‘exposure therapy’ carried out on humans. However, with exposure therapy the fear returns after a period of time. Dr Cho says this is because the connections between the neurons controlling the initial fear are not completely abolished.
In this study, the team used optogenetics to clear the connections between the fear associated neurons. In this study the researchers used a virus to introduce genes into particular neurons in the mice. These neurons were then able to produce proteins that responded to light in predictable ways, allowing the researchers to control the activity of neurons. When the neurons were exposed to low frequency light the connections between the neurons is weakened, completely eradicating the fear memory.
This is early research, and we are nowhere near inducing optogenetic changes in humans, or being able to erase memories ‘Eternal sunshine of the spotless mind’ style. But it does give us more information about the biology of fear and ways to modulate those pathways. Research such as this will one day hopefully lead us to effective treatment of conditions such as post-traumatic stress disorder.
A hard nut to crack
The joy of discovering cake in the office can quickly turn to disappointment for some after discovering two little words ‘contains nuts’. For some, especially children, this can be very serious. But the tide could be turning and for a proportion of people with nut allergies there could be a solution.
In 2015 a group of researchers from Murdoch University treated a small group (56) of children with an oral probiotic containing a peanut protein in an attempt to develop resistance to the peanut protein, a method call oral immunotherapy. This month the same researchers have published the result of a 4 year follow up. They have shown that 4 years after completion of the therapy 16 of the 24 previously allergic participants in this small trial were eating peanuts without adverse reactions. This study is the first demonstration of such prolonged sustained unresponsiveness with any form of peanut oral immunotherapy. Amazingly, a group of the follow up patients were asked to stop ingesting peanuts for 8 weeks to test the effect of infrequent exposure. After again ingesting peanut proteins, 7 of the 12 participants were still unresponsive to the peanut protein.
This is a small sample set, and hopefully the researchers will see the same level of success in a larger study.