title: Following brain trauma, copeptin, a stable peptide derived from the AVP precusor, does not reflect osmoregulation but correlates with injury severity.
abstract: The incidence of water and electrolyte disturbances following traumatic brain injury (TBI) is considerable and has been attributed to a dysregulation of the hypothalamic peptide arginine-vasopressin (AVP). Copeptin, the C-terminal part of the AVP prohormone, reflects AVP activity. In 71 TBI patients we measured copeptin in serum by a sandwich immunoassay. Injury severity was assessed by Glasgow Coma Score (GCS) and computed tomography, and recovery by Glasgow Outcome Score (GOS). Neuroendocrine and osmoregulation regulation were examined on day 0, 3 and 7, and 24 months post-injury. Copeptin was highest on admission (40.0 +/- 72.3 pmol/l), stabilized on day 3 and 7 (21.2 +/- 18.3 resp. 20.3 +/- 17.1 pmol/l), and normalized at follow-up (4.2 +/- 1.7 pmol/l). On admission, there was a correlation between serum sodium and urine excretion (p = 0.003), but the correlation got lost on day 3 and 7. Copeptin did not reflect the individual 24 h urine excretion or serum sodium levels indicating an uncoupling of copeptin/AVP release and renal water excretion. High copeptin level on day 3 were correlated with a low GCS (p < 0.001), midline shift (p = 0.019), intracerebral hemorrhage (p = 0.026), SAPS score (p = 0.001), as well as with a low GOS (p = 0.031). Copeptin was significantly decreased following skullbase fracture (p = 0.016).Our data reveal a loss of hypothalamic osmoregulation following TBI. The measurement of Copeptin/AVP release reveals a significant predictive function for the severity of TBI.
authors.affiliation: Department of Neurosurgery, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany. andrea.kleindienst@uk-erlangen.de
authors.forename: A
authors.initials: A
authors.lastname: Kleindienst
authors.forename: G
authors.initials: G
authors.lastname: Brabant
authors.forename: N G
authors.initials: NG
authors.lastname: Morgenthaler
authors.forename: K C
authors.initials: KC
authors.lastname: Dixit
authors.forename: H
authors.initials: H
authors.lastname: Parsch
authors.forename: M
authors.initials: M
authors.lastname: Buchfelder
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001930:Brain Injuries / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D015600:Glasgow Coma Scale; D006020:Glycopeptides / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012964:Sodium / Q000097:blood; D013997:Time Factors; D014882:Water-Electrolyte Balance / Q000502:physiology*; D055815:Young Adult
chemical_list: D006020:Glycopeptides; C048197:copeptins; D012964:Sodium