Story by Steve Vanderwerff on 07/19/2019SILVER SPRING, Md. Naval Medical Research Center (NMRC) and Walter Reed National Military Medical Center scientists presented their findings on structural and functional changes that occur when brain blood vessels are exposed to blast overpressure during the Uniformed Services University of the Health Sciences in Bethesda, Maryland's NCC Neuroscience Research Day June 10.
During their presentation, "Exposure to Blast Overpressure Impairs Cerebral Microvascular Responses and Alters Vascular and Astrocytic Structure," they explained how their study is the first to use an animal model and can be used to help wounded service members.
Recent conflicts in Iraq and Afghanistan have resulted in deployed personnel suffering severe closed and penetrating head injury not seen since the Vietnam era. Because clinical findings and causalities show an association between blast overpressure and increased brain blood vessel reactivity (cerebral vasospasm), the team of scientists set a course to investigate how to have a better understanding of how wounded warfighters suffering from ruptured brain aneurysms can receive better medical treatment.
"Initially mechanisms contributing to blood vessel response were unclear, which gave us a reason to further evaluate the relationship between blast and functional alterations of supplying blood to the brain and investigate potential underlying changes in blood vessel microstructure," said Dr. Steven Ahlers, director, Operational and Undersea Medicine. "According to our research we determined badly hurt warfighters with ruptured brain aneurysms have a higher risk of death."
According to co-author Dr. Randy Bell, Chief of Neurological Surgery at Walter Reed National Military Medical Center, "changes in their animal model began to reveal some of the underlying mechanisms of vasospasm observed clinically in service members with blast-related head injury.
"Results showed delays in brain vessels resulting from more than simple mechanical deformation of tissue," he said. "At its heart, blast-related traumatic brain injury may be caused by brain vessel disease."
The collected data shows how exposure to blast can result in delayed and prolonged alterations to brain vessel reactivity associated with changes in the micro-architecture of the vessel wall and astrocytes, the star-shaped glial cells of the central nervous system.
"These changes might contribute to long-term pathologies involving dysfunction of the neurovascular unit, including cerebral vasospasm," said Ahlers. "This ground breaking research elegantly demonstrates the power of clinical and translational research, and will be foundational for further work in this area."
Moving forward, Ahlers and his team continue with their research to have a better understanding of the changes in brain blood vessel after blast.
"Better knowledge of the underlying mechanisms of this injury could provide new therapies for wounded Sailors and Marines," Ahlers said.
About Naval Medical Research Center
NMRC's eight laboratories are engaged in a broad spectrum of activity from basic science in the laboratory to field studies at sites in austere and remote areas of the world to operational environments. In support of the Navy, Marine Corps, and joint U.S. warfighters, researchers study infectious diseases, biological warfare detection and defense, combat casualty care, environmental health concerns, aerospace and undersea medicine, medical modeling, simulation and operational mission support, and epidemiology and behavioral sciences.