Carry the One Radio

I recently joined a UCSF Neuroscience initiative called Carry the One Radio, a series of 10 minute long interviews with scientists from various backgrounds and institutions. Started two years ago by fellow graduate student Sama Ahmed, Carry the One aims to get high school and college students interested in science through relaying a scientist's story about he or she got interested in science, and "the one" project that creates the fire in their belly. I'm co-hosting the show with Sama, and we're now posting episodes on the web every month. This month, Sama talks to Cori Bargmann, a professor at the Rockefeller University and investigator at the Howard Hughes Medical Institute. Dr.Bargmann studies the neuronal circuitry underyling animal behavior using the humble worm, C.elegans, as a model system. She has also been featured on the Charlie Rose Brain Series and The New York Times. 

The website is still under construction, but please check out the latest episode here!:

http://www.carrytheoneradio.com/2012/07/01/cornelia-bargmann/

Please also check out the Facebook page at: http://www.facebook.com/carrytheone

Bacteria that influences happiness

In a recent study from the Alimentary Pharmabiotic Center, scientists showed that the bacteria that live in our gut during development can affect adult brain function and emotional states. Specifically, these little microbes are able to affect levels of the chemical serotonin in our brains. Serotonin, a neurotransmitter, plays an important role in the regulation of mood and emotion. Research has found that serotonin levels are altered during stress, anxiety and depression and many antidepressant drugs are designed to target this neurotransmitter. 

In this study, the scientists were able to demonstrate that mice that were raised in a germ-free environment and therefore had very little gut flora or microbiota during early life. This early absence of gut bacteria significantly elevated concentrations of serotonin in the adult brain, specifically in the hippocampus, a neuronal structure that has important roles in episodic and emotional memory. Most importantly, these germ-free mice with increased levels of serotonin during development displayed less anxious behavior when tested as adults, as compared to mice that were raised in normal conditions and had normal gut flora. Interestingly, this effect seemed to be sex-specific; male mice with reduced gut flora and subsequent elevated levels of hippocampal serotonin showed a much more marked effect than female mice. 

Intriguingly, the neurochemical effect seems to be irreversible. When the scientists recolonized the young germ-free mice in a normal environment that would allow the restoration of intestinal microbiota, they found that hippocampal serotonin levels continued to be elevated in these mice. Paradoxically, the restoration of the gut flora was able to reverse the behavioral effect, such that the germ-free mice no longer showed reduced anxiety compared to the control animals. 

This study follows  earlier work from several groups, showing that a microbiome-gut-brain axis exists and that it is essential for maintaining normal health which can affect brain and behaviour. The research was carried out by Dr Gerard Clarke, Professor Fergus Shanahan, Professor Ted Dinan and Professor John F Cryan and colleagues at the Alimentary Pharmabiotic Centre in UCC.

“As a neuroscientist these findings are fascinating as they highlight the important role that gut bacteria play in the bidirectional communication between the gut and the brain, and opens up the intriguing opportunity of developing unique microbial-based strategies for treatment for brain disorders”, said Professor John F Cryan, senior author on the publication and Head of the Department of Anatomy & Neuroscience at UCC.

The results from this study have many implications, as it shows that manipulating the natural microbiota that exist in our body, whether it be through infection, antibiotics or diet, can profoundly affect other bodily functions, including brain function and behavior. “We’re really excited by these findings” said lead author Dr Gerard Clarke. “Although we always believed that the microbiota was essential for our general health, our results also highlight how important our tiny friends are for our mental wellbeing.”

Vaccine trial for Alzheimer's Disease

Alzheimer’s disease (AD) is a complex neurological disease that is the most common form of dementia, or loss of brain function. Individuals suffering from Alzheimer's display impairments in learning and memory, as well as changes in personality and mood. According to the World Health Organisation, dementia is currently the fastest growing global health epidemic. AD is most often diagnosed in people that are older than 65, although there are a few rare cases of early-onset of the disease. The prevailing hypothesis about the cause of AD involves the protein amyloid precursor protein (APP), which is found in the outer membrane of nerve cells and that, instead of being broken down, forms a harmful substance called beta-amyloid. This noxious version of the protein can accumulate as plaques and kill brain cells. Needless to say, the disease is devastating to many all over the world, and a huge cost for society. 

Researchers around the world have been investigating genetic and environmental factors that may put individuals at risk, as well as how beta-amyloid can cause neurodegeneration. Moreover, other theories besides the APP theory exist to explain the cause of AD. While there is currently no cure for the disease, scientists have been trying different approaches to treat the disease; one of them has been vaccines. The first vaccination study conducted almost a decade ago, showed some efficiency in clearing up beta-amyloid plaques, but did not help with dementia at all. Furthermore, the vaccine caused too many adverse side effects, including an autoimmune reaction, and was soon abandoned. 

A recent study from researchers at the Karolinska Institutet in Stockholm points to the first successful attempt at a vaccine treatment for AD. The new treatment is an active vaccine and the idea is to use a type of vaccine designed to trigger the body's immune defence against beta-amyloid. In this set of clinical trials, the vaccine was modified such that it only affects the harmful form of APP, that is beta-amyloid. The investigators observed that 80 per cent of the participating patients developed protective antibodies against beta-amyloid, without suffering any side effects that were observed in previous trials of this study. The researchers believe that the treatnent, called CAD106 vaccine, could be an effective and tolerable way to treat patients with mild to moderade AD. More large-scale clinical trials have to be conducted to further determine the efficacy of CAD106, but the discovery is very encouraging for AD patients and their families.