Correlation between APOE-491AA promoter in ε4 carriers and clinical deterioration in early stage of traumatic brain injury

The objective of this work was to investigate the relationship between apolipoprotein E (APOE) promoters (G-219T, C-427T, A-491T) polymorphisms and the clinical deterioration in early stage of traumatic brain injury (TBI) in a cohort of Chinese patients. In this study, we used the cohort of patients which has been reported previously. A total of 110 subjects with TBI (80 males and 30 females, with mean age of 43.87 years) were admitted from December 2003 to May 2004, and demographic and clinical data were collected. The clinical deterioration of patient's condition in acute stage (< 7 days after TBI) was judged by either of the following criteria: decrease of Glasgow Coma Scale (GCS) score (compared with initial admission GCS), increase in hematoma volume or delayed hematoma both detected by repeated computed tomography (CT) scanning compared to that on admission. Venous blood was collected from patients with TBI on admission to determine the APOE promoter polymorphisms. The APOE genotyping was performed by means of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). chi(2) test and logistic regression analyses were done by SPSS. In 110 Chinese patients, the distributions of APOE genotypes and alleles matched Hardy-Weinberg Law, and 19 subjects presented with deteriorated clinical condition in acute stage after hospitalization. chi(2) test showed insignificant differences in association of APOE promoter polymorphisms with clinical deterioration (p > 0.05). But logistic regression analyses, after adjusting patients' age, injury severity and injury mechanism etc, showed that -491AA (OR = 11.681, p = 0.009, 95%, CI 1.824-74.790) and APOE epsilon 4 were all risk factors, with injury severity and alcohol-drinking as other risk factors. In Chinese population, as a significant but not independent risk factor, only APOE -491AA promoter in epsilon 4 carriers is apt to the clinical deterioration and may contribute to the poor outcome after TBI.