title: Neuroenergetic Response to Prolonged Cerebral Glucose Depletion after Severe Brain Injury and the Role of Lactate.
abstract: Lactate may represent a supplemental fuel for the brain. We examined cerebral lactate metabolism during prolonged brain glucose depletion (GD) in acute brain injury (ABI) patients monitored with cerebral microdialysis (CMD). Sixty episodes of GD (defined as spontaneous decreases of CMD glucose from normal to low [<1.0 mmol/L] for at least 2 h) were identified among 26 patients. During GD, we found a significant increase of CMD lactate (from 4 ± 2.3 to 5.4 ± 2.9 mmol/L), pyruvate (126.9 ± 65.1 to 172.3 ± 74.1 μmol/L), and lactate/pyruvate ratio (LPR; 27 ± 6 to 35 ± 9; all, p < 0.005), while brain oxygen and blood lactate remained normal. Dynamics of lactate and glucose supply during GD were further studied by analyzing the relationships between blood and CMD samples. There was a strong correlation between blood and brain lactate when LPR was normal (r = 0.56; p < 0.0001), while an inverse correlation (r = -0.11; p = 0.04) was observed at elevated LPR >25. The correlation between blood and brain glucose also decreased from r = 0.62 to r = 0.45. These findings in ABI patients suggest increased cerebral lactate delivery in the absence of brain hypoxia when glucose availability is limited and support the concept that lactate acts as alternative fuel.
authors: 1 Department of Intensive Care Medicine, University of Lausanne , Switzerland .
authors: Camille
authors: C
authors: Patet
authors: 1 Department of Intensive Care Medicine, University of Lausanne , Switzerland .
authors: Hervé
authors: H
authors: Quintard
authors: 1 Department of Intensive Care Medicine, University of Lausanne , Switzerland .
authors: Tamarah
authors: T
authors: Suys
authors: 2 Department of Clinical Neurosciences, University of Lausanne , Switzerland .
authors: Jocelyne
authors: J
authors: Bloch
authors: 2 Department of Clinical Neurosciences, University of Lausanne , Switzerland .
authors: Roy T
authors: RT
authors: Daniel
authors: 3 Departement of Physiology, University of Lausanne , Switzerland .
authors: Luc
authors: L
authors: Pellerin
authors: 4 Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology , Thuwal, Kingdom of Saudi Arabia .|5 Department of Psychiatry, Centre Hospitalier Universitaire Vaudois , Lausanne, Switzerland .|6 Laboratory of Neuroenergetics and Cellular Dynamics, Brain Mind Institute , Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland .
authors: Pierre J
authors: PJ
authors: Magistretti
authors: 1 Department of Intensive Care Medicine, University of Lausanne , Switzerland .
authors: Mauro
authors: M
authors: Oddo
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D001930:Brain Injuries / Q000097:blood / Q000378:metabolism*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D008875:Middle Aged; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D019344:Lactic Acid; D005947:Glucose
keywords: brain injury; cerebral metabolism; cerebral microdialysis; glucose; lactate