(This is an excerpt of the Health Rounds newsletter, where we present latest medical studies on Tuesdays and Thursdays)
By Nancy Lapid
Aug 26 (Reuters) – We also cover a method for improving speech after a brain injury and a finding on how blood vessels form following a heart attack.
COULD FLU VACCINES BE “BREWED” IN YEAST?
A new process for manufacturing flu vaccines in baker’s yeast might someday replace the current 80-year-old process that uses chicken eggs while offering potentially significant advantages as well, researchers reported.
Not only would such vaccines be cheaper, but they might make yearly flu shots obsolete by providing long-lasting protection against multiple influenza strains, the researchers said at the American Chemical Society meeting in Chicago.
Most vaccines target hemagglutinin, a viral surface protein that triggers a strong immune response. But hemagglutinin mutates rapidly, requiring the design of a new vaccine — and another shot in the arm — each year.
The new vaccines target a different viral protein known as M2, which is far less prone to mutation. It has hardly changed since the 1918 flu pandemic, the researchers said.
By targeting a highly conserved viral protein such as M2, the researchers hoped the resulting vaccine would provide broad protection that lasts longer than a year, perhaps even a lifetime.
Along with targeting M2, they aimed to develop a more cost-effective, rapid system for manufacturing at large scale that doesn’t require incubation in chicken eggs. Their approach uses baker’s yeast (Saccharomyces cerevisiae) to produce virus-like particles that display the M2 protein on their surface but do not contain the genetic viral material that causes infection.
Mice vaccinated with the purified M2 virus-like particles were protected against infection from three different influenza strains, the researchers found.
Although the findings in mice are promising, work still needs to be done before it is ready for human trials, the researchers say.
“I would definitely anticipate that the M2 vaccine provides broader and longer protection than the current HA-focused vaccines,” senior researcher Fei Wen of the University of Michigan said in a statement.
“Can it be even longer than that, like once in a lifetime? Possibly, or maybe people will need a booster when they get older.”
The team has licensed the technology to a company developing yeast systems to produce oral vaccines. Wen speculates that someday, engineered yeast strains could be “brewed” as oral vaccines for influenza and other diseases.
ELECTRICAL CURRENTS CAN IMPROVE SPEECH AFTER BRAIN INJURY
Low-frequency electrical currents delivered deep in the brain might help improve speech and swallowing problems caused by traumatic brain injury, early experiments suggest.
In proof-of-concept experiments, stimulation of the brain’s motor thalamus improved control of facial and tongue muscles involved in speaking and swallowing, researchers reported in Nature Communications.
“Rehabilitating speech deficits after an injury is a top priority for many people, often even more than mobility,” study leader Elvira Pirondini of the University of Pittsburgh said in a statement.
“For many people, losing speech affects work, independence and relationships. It can have a profound effect on a person’s life,” Pirondini said.
Because high-frequency stimulation has been shown to have a suppressive, negative effect on speech, the Pittsburgh scientists lowered the frequency by almost threefold.
Participants in the first phase of the experiments were having deep brain stimulation devices implanted for treatment of essential tremor. In these volunteers, low-frequency deep brain stimulation increased activation of face and throat muscles without worsening speech, the researchers found.
When tested in a traumatic brain injury survivor with profound speech difficulties, the low-frequency treatments improved facial muscle movement, swallowing and speech control.
This patient’s word intelligibility improved by 8%, 20% and 16% across three testing sessions when stimulation was on, compared with stimulation off.
A 7% change is considered a small clinically significant improvement and a 15% change is considered large, the researchers noted.
The findings suggest that low-frequency motor thalamus deep brain stimulation deserves further study as a potential neuromodulation strategy for speech and swallowing problems after TBI and other brain lesions, the researchers said.
AFTER A HEART ATTACK, NEW BLOOD VESSELS GROW FROM CAPILLARIES, NOT ARTERIES
Studies in mice challenge a long-standing view of how the heart builds new blood vessels around an artery blockage, Chinese researchers say.
The new vessels, which act as natural bypasses, arise primarily from capillaries – the smallest blood vessels in the body — rather than from strong, thick-walled arteries, they reported in Science.
Traditionally, collateral coronary vessels were thought to form when arterial connections enlarged in response to increased blood-flow forces following an obstruction. Recent research has shown these vessels can also arise from scratch, or “de novo,” but how this happens has been unclear.
Using genetically engineered mice and genetic lineage-tracing tools to track the origins of the cells of collateral blood vessels, researchers found that for the most part, they arose from the cells that line capillaries.
They also found that using mRNA to deliver VEGF-A – a protein involved in blood vessel growth — significantly promoted the formation of functional collateral arteries and improved heart damage repair in the mice.
The findings offer insight into a molecular pathway that could be leveraged to promote cardiac repair, the Chinese research team said.
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(Reporting by Nancy Lapid; Editing by Bill Berkrot)
