Plasma concentrations of arginine and related amino acids following traumatic brain injury: Proline as a promising biomarker of brain damage severity.
The aim of this study was to find a plasma biomarker, in relation with nitric oxide (NO), as a sign of brain damage severity following traumatic brain injury (TBI). We first investigated the post-traumatic evolution of the plasma concentrations of NO via the level of NO end-products metabolites (nitrite plus nitrate, NO(x)), that of l-arginine (Arg) and amino acids involved in its metabolism as well as the time course of neurological score in a rat model of lateral fluid percussion brain injury. First, the level of NO(x) was increased in plasma at 24 and 48 h post-TBI with a marked increase at 72 h. In contrast, this elevation was neither accompanied by a modification of plasma concentrations of Arg, nor of amino acids involved in NO and Arg metabolism, l-ornithine (Orn), l-glutamate (Glu), and l-glutamine (Gln). Second, TBI induced a fall of plasma l-proline (Pro) concentrations. The time course of post-TBI neurological deficit showed also a decrease of neurological score at 24, 48, and 72 h. Furthermore, there is a weak negative correlation between the neurological score and the plasma level of NO(x) (r=-0.305; P<0.05), while a marked positive correlation has been found between the neurological score and the plasma level of Pro (r=0.563; P<0.001). In conclusion, the plasma concentrations of Pro could be a promising marker of post-traumatic neurological deficit.
Louin
G
G
Université Paris Descartes, Laboratoire de Pharmacologie (UPRES EA 2510), 4, avenue de l'Observatoire, 75270 Paris cedex 06, France.
Neveux
N
N
Cynober
L
L
Plotkine
M
M
Marchand-Leroux
C
C
Jafarian-Tehrani
M
M
D000596:Amino Acids / Q000097:blood; D000818:Animals; D001120:Arginine / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D001930:Brain Injuries / Q000175:diagnosis*; D023421:Models, Animal; D009569:Nitric Oxide / Q000097:blood; D011392:Proline / Q000097:blood*; D051381:Rats; D012720:Severity of Illness Index; D013997:Time Factors; D015599:Trauma Severity Indices
D000596:Amino Acids; D015415:Biomarkers; D009569:Nitric Oxide; D001120:Arginine; D011392:Proline