Clinical cerebral microdialysis: a methodological study

Hutchinson, Peter J.; O’Connell, Mark; Al-Rawi, Pippa G.; Maskell, L.; Kett-White, Rupert; Gupta, Arun Kumar; Richards, Hugh K.; Hutchinson, David; Kirkpatrick, Peter J.; Pickard, John D.

doi:10.3171/jns.2000.93.1.0037

Cited by 226 publications

(166 citation statements)

References 33 publications

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“…1 Under standard conditions (10 mm microdialysis membrane and 0.3 µl/minute perfusion rate), biomarker recoveries (dialysate/interstitial fluid concentration) are~70%. 2 Because cytoplasmic lactate and pyruvate readily exchange with extracellular fluids (including blood and perfusion media 3 ), the lactate/ pyruvate ratio (LPR) is considered a reliable index of intracellular cytoplasmic redox state, the [ [3][4][5] Microdialysate LPRs are very useful but not diagnostically specific. 6 Poor outcome after TBI is associated with low oxygen, glucose, pyruvate levels, high LPR, and elevated glutamate and glycerol levels, particularly when changes have longer duration and higher magnitude.…”

Section: Brain Microdialysis After Traumatic Brain Injurymentioning

confidence: 99%

Lactate Shuttling and Lactate use as Fuel after Traumatic Brain Injury: Metabolic Considerations

Dienel

2014

J Cereb Blood Flow Metab

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Lactate is proposed to be generated by astrocytes during glutamatergic neurotransmission and shuttled to neurons as 'preferred' oxidative fuel. However, a large body of evidence demonstrates that metabolic changes during activation of living brain disprove essential components of the astrocyte-neuron lactate shuttle model. For example, some glutamate is oxidized to generate ATP after its uptake into astrocytes and neuronal glucose phosphorylation rises during activation and provides pyruvate for oxidation. Extension of the notion that lactate is a preferential fuel into the traumatic brain injury (TBI) field has important clinical implications, and the concept must, therefore, be carefully evaluated before implementation into patient care. Microdialysis studies in TBI patients demonstrate that lactate and pyruvate levels and lactate/pyruvate ratios, along with other data, have important diagnostic value to distinguish between ischemia and mitochondrial dysfunction. Results show that lactate release from human brain to blood predominates over its uptake after TBI, and strong evidence for lactate metabolism is lacking; mitochondrial dysfunction may inhibit lactate oxidation. Claims that exogenous lactate infusion is energetically beneficial for TBI patients are not based on metabolic assays and data are incorrectly interpreted.

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Section: Brain Microdialysis After Traumatic Brain Injurymentioning

confidence: 99%

Lactate Shuttling and Lactate use as Fuel after Traumatic Brain Injury: Metabolic Considerations

Dienel

2014

J Cereb Blood Flow Metab

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“…The analyzer is controlled by a standard personal computer and calibrates automatically every 6 hours. We have previously validated the analysis of microdialysis samples for glutamate using the CMA600 by comparing measurements obtained using the gold standard of highperformance liquid chromatography (Hutchinson et al, 2000d).…”

Section: Microdialysis Techniquementioning

confidence: 99%

Correlation between Cerebral Blood Flow, Substrate Delivery, and Metabolism in Head Injury: A Combined Microdialysis and Triple Oxygen Positron Emission Tomography Study

Hutchinson

Gupta

Fryer

et al. 2002

J Cereb Blood Flow Metab

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150

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Summary:Microdialysis continuously monitors the chemistry of a small focal volume of the cerebral extracellular space. Conversely, positron emission tomography (PET) establishes metabolism of the whole brain, but only for the duration of the scan. The objective of this study was to apply both techniques to head-injured patients simultaneously to assess the relation between microdialysis (glucose, lactate, lactate/pyruvate [L/P] ratio, and glutamate) and PET (cerebral blood flow [CBF], cerebral blood volume, oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen) parameters. Microdialysis catheters were inserted into the frontal cerebral cortex and adipose tissue of the anterior abdominal wall of 17 severely headinjured patients. Microdialysis was performed during PET scans, with regions of interest defined by the location of the microdialysis catheter membrane. An intervention (hyperventilation) was performed in 13 patients. The results showed that combining PET and microdialysis to monitor metabolism in ventilated patients is feasible and safe, although logistically complex. There was a significant relation between the L/P ratio and the OEF (Spearman r ‫ס‬ 0.69, P ‫ס‬ 0.002). There was no significant relation between CBF and the microdialysis parameters. Moderate short-term hyperventilation appeared to be tolerated in terms of brain chemistry, although no areas were sampled by microdialysis where the OEF exceeded 70%. Hyperventilation causing a reduction of the arterial carbon dioxide tension by 0.9 kPa resulted in a significant elevation of the OEF, in association with a reduction in glucose, but no significant elevation in the L/P ratio or glutamate.

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“…13,15) Lower extracellular glucose concentration was associated with higher lactate/pyruvate ratio in our elderly patients, so cerebral hypoperfusion may have persisted in elderly patients with head injury longer than in younger patients.…”

Section: Discussionmentioning

confidence: 99%

Lower Extracellular Glucose Level Prolonged in Elderly Patients With Severe Traumatic Brain Injury: A Microdialysis Study

Yokobori

Watanabe

Matsumoto

et al. 2011

Neurol. Med. Chir.(Tokyo)

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Age may be an independent predictor of outcomes in traumatic brain injury (TBI), but the causes of the poor outcomes in elderly patients remain unclear. To clarify the differences between elderly and young patients with TBI, brain metabolism parameters were monitored with the microdialysis method in 30 patients with severe TBI (Glasgow Coma Scale scores 3-8). The microdialysis probe was inserted in the penumbra area of the brain and extracellular levels of glucose, glutamate, glycerol, lactate, and pyruvate were measured hourly for the initial 168 hours (7 days) after operation. The lactate/pyruvate ratio, which is considered to be a good indicator of neuronal ischemia, was also calculated. The patients were divided into the elderly group aged 65 years or older and the young group aged less than 65 years, and the biochemical markers were compared daily between these two groups. The value of extracellular glucose concentration was significantly lower in the elderly group than in the young group, and continued until the 7th day after injury. Moreover, the lactate/pyruvate ratio peaked on the 5th day after injury in the elderly group, later than in the young group. We concluded that neural vulnerability persisted longer in elderly patients than in young patients with TBI, and this should be considered to prevent the occurrence of additional secondary brain injury.

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Clinical cerebral microdialysis: a methodological study

Cited by 226 publications

References 33 publications

Lactate Shuttling and Lactate use as Fuel after Traumatic Brain Injury: Metabolic Considerations

Lactate Shuttling and Lactate use as Fuel after Traumatic Brain Injury: Metabolic Considerations

Correlation between Cerebral Blood Flow, Substrate Delivery, and Metabolism in Head Injury: A Combined Microdialysis and Triple Oxygen Positron Emission Tomography Study

Lower Extracellular Glucose Level Prolonged in Elderly Patients With Severe Traumatic Brain Injury: A Microdialysis Study

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