Blast-Induced Neurotrauma Results in Spatially Distinct Gray Matter Alteration Alongside Hormonal Alteration: A Preliminary Investigation

• Published in: International journal of molecular sciences 2023-04, Vol.24 (7), p.6797
• Main Authors: Hellewell, Sarah C, Granger, Douglas A, Cernak, Ibolja
• Format: Article
• Language: English
• Subjects: Analysis; Armed Forces; blast (explosion) wave-induced neurotrauma; Blast Injuries; Brain; Brain research; brain volume changes; Canada; Cognition; Corticosteroids; Cortisol; Emergency response; Gray Matter; Hormones; Humans; Hydrocortisone; Hypothalamus; Investigations; Job stress; Magnetic Resonance Imaging; military; Military engineering; Military personnel; Morphometry; Occupational stress; Pituitary; Post traumatic stress disorder; Psychological stress; Saliva; Stress management; Substantia grisea; Temporal gyrus; Testosterone; Thalamus; Training; Trauma; Traumatic brain injury; traumatic brain injury (craniocerebral trauma); Veterans
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms24076797

Blast-induced neurotrauma (BINT) frequently occurs during military training and deployment and has been linked to long-term neuropsychological and neurocognitive changes, and changes in brain structure. As military personnel experience frequent exposures to stress, BINT may negatively influence stress coping abilities. This study aimed to determine the effects of BINT on gray matter volume and hormonal alteration. Participants were Canadian Armed Forces personnel and veterans with a history of BINT ( = 12), and first responder controls ( = 8), recruited due to their characteristic occupational stress professions. Whole saliva was collected via passive drool on the morning of testing and analyzed for testosterone (pg/mL), cortisol (μg/dL), and testosterone/cortisol (T/C) ratio. Voxel-based morphometry was performed to compare gray matter (GM) volume, alongside measurement of cortical thickness and subcortical volumes. Saliva analyses revealed distinct alterations following BINT, with significantly elevated testosterone and T/C ratio. Widespread and largely symmetric loci of reduced GM were found specific to BINT, particularly in the temporal gyrus, precuneus, and thalamus. These findings suggest that BINT affects hypothalamic-pituitary-adrenal and -gonadal axis function, and causes anatomically-specific GM loss, which were not observed in a comparator group with similar occupational stressors. These findings support BINT as a unique injury with distinct structural and endocrine consequences.