Publication: The correlation of plasma levels of Brain Derived Neurotrophic Factor (BDNF) and C-tau protein with the Simplified Acute Physiology Score II (SAPS II) in critically ill patients.
Date
2013-05
Authors
Nik, Wan Nurul 'Izzati Wan
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Abstract
Brain Derived Neurotrophic Factor (BDNF) has been found at low concentration in the plasma of healthy persons and shows a high concentration after neuronal damage. It is related to the fact that BDNF is needed for recovery7 of brain function after acute stress and the decrease of its level in patients has been suggested to be related to the inability of these patients to cope with acute stress. Meanwhile, cleaved tau level was also higher in head injury patients compared to healthy peoples. Increased serum cleaved tau protein was associated with a greater chance of intracranial injury and poor outcome in patients with closed head injuries. C-tau protein had been suggested to be the biomarker with specificity for brain injury' because C-tau elevations had been discovered in patients with neurodegenerative disease and severe head injuries. A severity scoring system had been introduced and developed to allow an assessment of the severity7 of disease and provide an estimate of in-hospital mortality. This estimate is achieved by collecting routinely measured data specific to a patient. It is found that Simplified Acute Physiology Score II (SAPS II) is now the simplest system for measuring intensive care unit (ICU) performances precisely and comparing performance over years because the expanded SAPS 11 is simple to obtain from the existing data bases. This study compared the level of specific biochemical markers of axonal damage (C-tau protein) and nerve growth factor (BDNF) in critically ill patients with that of healthy subjects. The protein levels were then correlated with the severity scores (SAPS If)- AU protein levels were determined by using the Cusabio ELISA kit and the scores for SAPS II of all patients were obtained from a Microsoft Excel programme that was developed by BRAINetwork. In this study, it was found that the plasma levels of BDNF and C-tau in healthy volunteers were higher when compared to the plasma levels [median] of BDNF and C-tau in ICU patients (0.155 versus 0.111 ng/ml) and (0.579 versus 0.199 ng/ml) respectively. Both tests also showed a significant difference (p< 0.05) with the following p values for BDNF (p= 0.00) and C-tau (p=0.003). 'Hie initial finding showed that plasma levels of BDNF and C-tau were not associated with severity of illness in ICU patients. This is in contrast to other studies, and is now the subject of further analysis in a separate study at BRAINetwork. The difference in findings may be related to the onset of neuronal damage prior to the admission of these patients into the ICU. However, this study has found a positive correlation between BDNF and C-tau protein levels with the severity' scores (SAPS 11) where lower scores of SAPS 11 for each patient is directly proportional to the lower levels of BDNF and C-tau protein in critically ill patients.
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Keywords
Brain derived neurotrophic factor (BDNF)