Significance of Serum and Urinary Malonate Concentration in Patients with Traumatic Brain Injury

Kim, Dong Hoon; Ha, Young Soo; Park, Chong Oon

Abstract

When the brain is damaged, lipid peroxidation and malonate concentration are increased. The malonate activates the NMDA receptor and induces neuronal toxicity. To investigate the importance of malonate concentration as a prognostic factor, we measured its concentration in serum and urine of 20 patients with head trauma from August 1993 to Feburary 1994. Controls were 20 healthy volunteers. Blood and urine samplings ware taken at first day after head trauma. Malonate concentration in serum and urine was measured by utilizing the malonyl-CoA synthetase from Rhizobium trifolii. Direct spectrophotometric assay at 540 nm was used for purification and characterization. Mean serum malonate concentration in patients with head trauma was 1.83+/-.64 mM/L and 0.72+/-.20 mM/L in controls. The serum malonate concentration in patients was more significantly increased than controls (p<0.05). Mean malonate concentraion in urine was 0.61+/-.28 mM/L and 0.76+/-.24 mM/L in controls. There was no significant difference between patients and controls(p>0.05). A regression analysis on the relationship between malonate concentration, higher the malonate concentration, worse the Glasgow Outcome(r=0.64). In conclusion, when head injury occurs, concentration of serum malonate increases and this tends to be related to poor outcome. But, it must be further investigated to varify whether the relationship between traumatic brain injury and malonate concentration is more closely related without other factors affecting its concentration.