Effective glutamate clearance from the systemic circulation by hemodialysis. Potential relevance for cerebral ischemia management.

Introduction High glutamate levels after head trauma or cerebral ischemia have neurotoxic effects. The objective of the present study was to evaluate the efficacy of hemodialysis to remove glutamate from the blood and to assess the behavior of this small molecule. Methods Ten patients with end-renal disease on hemodialysis were included in the study. Glutamate clearance was evaluated within the first hour of hemodialysis on a midweek dialysis day on five patients underwent low flux hemodialysis, whereas the other five patients underwent highly efficient hemodialysis (high flux hemodialysis on one day and on-line hemodiafiltration on another day). Findings Glutamate clearance with hemodialysis was very effective and did not show any differences between the techniques [low flux: 214 (55), high flux: 204 (37), on-line hemodiafiltration: 202 (16), median (interquartile range), p=0.7]. Glutamate clearance was almost equivalent to vascular access plasma flow and it was not affected by dialyzer permeability or ultrafiltration rate. After a hemodialysis session, a significant decrease in glutamate blood level was observed (pre-hemodialysis: 59.7 (36.1), post-hemodialysis 37.0 (49.2), p=0,005). Dialysis performed under fasting condition showed higher glutamate reduction rate (60%) than that under feeding condition (20%). Discussion Hemodialysis may be an effective method to reduce glutamate blood levels, and the molecule clearance does not differ between the different techniques used. Considering previous results in experimental models, hemodialysis without hemodynamic stress, could be considered for reducing glutamate neurotoxic effects in acute ischemic strokes of patients in chronic hemodialysis programs.