“Humans with wings” was what David Wassarman, a professor of cell and regenerative biology at the University of Wisconsin School of Medicine and Public Health, called flies at the McArdle Seminar in Cancer Biology on Wednesday April 30th. Wassarman has been studying traumatic brain injury by using fruit flies to aid his research.
Statistics show there are roughly 1.7 million new cases of traumatic brain injuries in the US each year, which is nearly the same as the number as new cancer cases, according to the US Centers for Disease Control. Wassarman referred to the clinical definition of traumatic brain injury which is “damage to the brain caused by mechanical force.” The leading causes of traumatic brain injury are falls and automobile accidents Wassarman added.
Research Focuses on Primary and Secondary Types of Brain Injury
Wassarman also explained how he distinguishes between two types of injuries: primary injuries and secondary injuries. Secondary injuries consist of cellular and molecular events, he noted. TBI causes physical problems, cognitive problems, behavioral problems, as well as brain cell death. Flies are useful models to study these injuries because they have similar but simpler innate immune responses to humans. A better understanding of the flies’ immune response will lead to an understanding of these mechanisms in humans, he said.
Wassarman added that he studies the secondary injuries, the cellular and molecular events that occur after the mechanical injury. He explained:
“We want to understand the fundamental aspects of TBI, and by using flies we can get at the fundamental cellular and molecular events that are occurring.”
Flies are inexpensive to house and breed rapidly with a very short life span, so they can be examined on a micro-scale over their entire lifetime, according to Wassarman. A variety of experimental tools like genetic screening can also be used on flies, he said.
Special Trauma Simulator used to Trigger Injury Response Mechanisms in Flies
Wassarman constructed a special device called high-impact trauma, which inflicts traumatic brain injury in flies. Flies are placed in a vial and slammed against a hard surface, causing harm to multiple body parts including the brain, he said. The team found traumatic brain injury causes temporary incapacitation, reduced lifespan, neurodegeneration, activation of the innate immune response and, in some cases, death.
The occurrence of death hinges on multiple factors including impact of force, age at the time of traumatic brain injury plus genetic background. Wassarman also said:
“Something is happening during the aging process, and if we can control that we can reduce the mortality from TBI.”
Older flies seem to have a higher mortality rate compared to younger flies after traumatic brain injury, Wassarman said. Studies could reveal a reason to medically treat older people affected by traumatic brain injury differently from younger people, he said.
Wassarman also believes that a fly’s genes affect the aging process, and in turn, the effects of traumatic brain injury. He also discovered a correlation between extended lifespan and reduced death from traumatic brain injury. His research team also identified genetic risk factors for TBI. Wasserman says this discovery could allow children and young adults with specific genetic makeups to be warned against playing football or other high-risk sports using genetic testing. Wassarman expressed his hope for the future:
“I’m hoping that what we are doing with flies will lead to new therapies in humans.”
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