Scientists already knew that certain molecules pop up in the blood after a brain injury, including glial fibrillary acidic protein (GFAP). This protein is normally found in glial cells, which are support cells in the brain that surround nerve cells. After an injury, GFAP bursts out of the glial cells and—most importantly—easily traverses the blood-brain barrier.
While scientists are working on commercial tests for GFAP, it wasn’t clear how long this protein stays in the blood. To find out, Papa and her colleagues tracked GFAP in the blood of 584 adult volunteers who came into their emergency room within four hours of a head injury. Based on CT scans, 325 of those patients had mild to moderate concussions. Volunteers whose CT scans revealed no concussion acted as controls in the study.
The volunteers' GFAP levels were tracked at regular intervals for as long as they were in the hospital. The longest stay was seven days. Patients who had taken hits but didn't develop concussions had nearly zero GFAP in their blood during the entire length of the study. For volunteers with mild to moderate concussions, the researchers found that GFAP stuck around at high levels for the first 60 hours before trailing off. But even seven days after the injury, researchers were still able to detect slightly elevated levels of GFAP.
The paper appears in JAMA Neurology - behind their paywall
Time Course and Diagnostic Accuracy of Glial and Neuronal Blood Biomarkers GFAP and UCH-L1 in a Large Cohort of Trauma Patients With and Without Mild Traumatic Brain Injury
Linda Papa, MDCM, MSc1; Gretchen M. Brophy, PharmD2,3; Robert D. Welch, MD, MS4; Lawrence M. Lewis, MD5; Carolina F. Braga, BA1; Ciara N. Tan, BS, MHSH1; Neema J. Ameli, BS1; Marco A. Lopez, AS1; Crystal A. Haeussler, BS1; Diego I. Mendez Giordano, BS1; Salvatore Silvestri, MD1; Philip Giordano, MD1; Kurt D. Weber, MD1; Crystal Hill-Pryor, PhD6; Dallas C. Hack, MD, MPH7
1Department of Emergency Medicine, Orlando Regional Medical Center, Orlando, Florida 2Department of Pharmacotherapy and Outcomes Science, Virginia Commonwealth University, Richmond 3Department of Neurosurgery, Virginia Commonwealth University, Richmond 4Division of Emergency Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan 5Division of Emergency Medicine, Washington University School of Medicine in St Louis, Missouri 6US Department of Defense, Silver Springs, Maryland 7Brain Health, Harpers Ferry, West Virginia
Importance Glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase L1 (UCH-L1) have been widely studied and show promise for clinical usefulness in suspected traumatic brain injury (TBI) and concussion. Understanding their diagnostic accuracy over time will help translate them into clinical practice.
Objectives To evaluate the temporal profiles of GFAP and UCH-L1 in a large cohort of trauma patients seen at the emergency department and to assess their diagnostic accuracy over time, both individually and in combination, for detecting mild to moderate TBI (MMTBI), traumatic intracranial lesions on head computed tomography (CT), and neurosurgical intervention.
Design, Setting, and Participants This prospective cohort study enrolled adult trauma patients seen at a level I trauma center from March 1, 2010, to March 5, 2014. All patients underwent rigorous screening to determine whether they had experienced an MMTBI (blunt head trauma with loss of consciousness, amnesia, or disorientation and a Glasgow Coma Scale score of 9-15). Of 3025 trauma patients assessed, 1030 met eligibility criteria for enrollment, and 446 declined participation. Initial blood samples were obtained in 584 patients enrolled within 4 hours of injury. Repeated blood sampling was conducted at 4, 8, 12, 16, 20, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, and 180 hours after injury.
Main Outcomes and Measures Diagnosis of MMTBI, presence of traumatic intracranial lesions on head CT scan, and neurosurgical intervention.
Results A total of 1831 blood samples were drawn from 584 patients (mean [SD] age, 40  years; 62.0% [362 of 584] male) over 7 days. Both GFAP and UCH-L1 were detectible within 1 hour of injury. GFAP peaked at 20 hours after injury and slowly declined over 72 hours. UCH-L1 rose rapidly and peaked at 8 hours after injury and declined rapidly over 48 hours. Over the course of 1 week, GFAP demonstrated a diagnostic range of areas under the curve for detecting MMTBI of 0.73 (95% CI, 0.69-0.77) to 0.94 (95% CI, 0.78-1.00), and UCH-L1 demonstrated a diagnostic range of 0.30 (95% CI, 0.02-0.50) to 0.67 (95% CI, 0.53-0.81). For detecting intracranial lesions on CT, the diagnostic ranges of areas under the curve were 0.80 (95% CI, 0.67-0.92) to 0.97 (95% CI, 0.93-1.00)for GFAP and 0.31 (95% CI, 0-0.63) to 0.77 (95% CI, 0.68-0.85) for UCH-L1. For distinguishing patients with and without a neurosurgical intervention, the range for GFAP was 0.91 (95% CI, 0.79-1.00) to 1.00 (95% CI, 1.00-1.00), and the range for UCH-L1 was 0.50 (95% CI, 0-1.00) to 0.92 (95% CI, 0.83-1.00).
Conclusions and Relevance GFAP performed consistently in detecting MMTBI, CT lesions, and neurosurgical intervention across 7 days. UCH-L1 performed best in the early postinjury period.
Females are often an unseen part of the concussion story even though they suffer more concussions than males, have more severe symptoms and are slower to recover. Just why is not completely clear, but the deficit in knowledge is slowly beginning to change thanks to women’s advocates behind Pink Concussions. The group gathered last weekend at Georgetown University to review the science behind concussions, and also to develop recommendations on gender-specific prevention protocols and clinical practices on how best to treat females with concussions.
In comparable sports “female rates of concussions are much higher than those of their male counterparts,” says Zachary Kerr, director of the National Collegiate Athletic Association (NCAA) Injury Surveillance Program. Over a five-year period the rates per 1000 athlete-exposures were 6.3 in females versus 3.4 in males in soccer, 6.0 in females versus 3.9 in males in basketball and 3.3 in females versus 0.9 in males in baseball and softball. Only in swimming and diving did male rates (0.3) exceed those of females (0.5). Headache, dizziness and difficulty concentrating were roughly similar among both sexes, Kerr says. But among injured high school athletes, “larger portions of females are reporting sensitivity to light, sensitivity to noise, nausea and drowsiness,” he says. They were also slower to return to normal activity.
She designed, built and drove it. She also set the land speed record for the type of vehicle. An interview -- among other things she holds a master's in mechanical engineering and is working on her Ph.D. Her blog...
This winter has also lacked what Alaskans call “deep cold,” in the range of minus 50 or lower, which may have implications for the trail. No weather station anywhere in the state, even in traditionally frigid spots of the interior, like Fairbanks, has recorded anything colder than minus 30 this year. Spring arrives in two weeks, and if that mark stands, it will be the first time in at least 100 years that no place in Alaska saw winter temperatures fall to minus 50, according to National Weather Service records.
Fewer days of such deep-freeze conditions creates the possibility of open water on the Iditarod course, which runs through the typical Alaskan bush mixture of rivers, bogs, lakes and swamps.
“It’s not just the average, but the lack of any deep cold. And it wouldn’t surprise me to learn about more open-water problems,” said Rick Thoman, the climate science and services manager for the National Weather Service in Alaska.
On Jan. 9, I had a similar feeling watching the National Football League wild-card game between the Pittsburgh Steelers and Cincinnati Bengals. An outrageous helmet-to-helmet hit by the Steeler Ryan Shazier gave Giovani Bernard a concussion, but astonishingly, it didn’t result in a penalty — the hit was apparently within the rules. The Bengals’s Vontaze Burfict’s savage shoulder-to-helmet hit on the defenseless wide receiver Antonio Brown caused another concussion (he couldn’t play in the next week’s divisional playoff), but at least Burfict’s recklessness drew a three-game suspension.
The negative publicity surrounding the game was more evidence that, despite its colossal cultural and economic success, the N.F.L. is in deep trouble, and can’t seem to find a way out. The still accumulating evidence of brain-damaged former players — Ken Stabler, who died in July, is the most recent one to show evidence of brain trauma — is a huge legal liability. The failure of the league to take effective actions to protect the brains of current players puts it into willful-negligence territory. Other than increasing some on-field penalties, the league has done almost nothing to protect players now or in the future. And the sports media are mostly shills paid by the networks to entertain audiences and please the league, with little interest in using their pulpit for the cause of player safety.