Peripheral plasma amino acid abnormalities in rehabilitation patients with severe brain injury

Objective: Acute severe brain injury causes an increased mobilization of amino acids from tissue. The plasma amino acid profile of patients undergoing rehabilitation after brain injury is unknown. This study was aimed at delineating the plasma amino acid profile of rehabilitation patients with brain injury. Design: Peripheral plasma aminogram, lactate, pyruvate, glycerol, ketone body, and carnitine concentrations were determined in 11 patients with brain injury (34.6 +/- 15 years old, 60 +/- 16.8 days after injury) and in 8 controls. Resting energy expenditure and nitrogen balance were also determined. Results: (1) All essential amino acids and about 50% of nonessential amino acids were significantly lower in brain injury patients than in controls (p < .05). (2) Plasma amino acids were lower irrespective of either energy and protein intake or nitrogen balance. (3) Total carnitine concentration and esterified/free carnitine ratio were higher in brain injury patients than in controls (p < .05). Conclusions: Rehabilitation patients with brain injury may have an important reduction of their plasma aminogram. Muscle tissue depletion and the persistence of a hypercatabolic state caused by subclinical infections, pressure sores, and immobility may contribute to this reduction.