title: [Association between serum aluminium level and methylation of amyloid precursor protein gene in workers engaged in aluminium electrolysis].
abstract: OBJECTIVE
  To investigate the association between serum aluminium level and methylation of the promoter region of amyloid precursor protein (APP)gene in workers engaged in aluminium electrolysis.
  
  
  METHODS
  In 2012, 366 electrolysis workers in an aluminium factory were enrolled as exposure group (working years >10 and age >40 years)and divided into low-exposure group and high-exposure group based on the median serum aluminium level. Meanwhile, 102 workers in a cement plant not exposed to aluminium were enrolled as control group. Graphite furnace atomic absorption spectrometry was used to measure serum aluminium level, methylation specific PCR was used to measure the methylation rate of the promoter region of APP gene, and ELI-SA was used to measure the protein expression of APP in lymphocytes in peripheral blood.
  
  
  RESULTS
  The exposure group had a significantly higher serum aluminium level than the control group (45.07 μg/L vs 30.51 μg/L, P< 0.01). The exposure group had a significantly lower methylation rate of the promoter region of APP gene than the control group (18.85% vs 25.49%, P=0.025), and the high-exposure group had a significantly lower methylation rate of the promoter region of APP gene than the low-exposure group (15.84% vs 21.85%, P<0.05). The exposure group had a significantly higher protein expression of APP in lymphocytes in peripheral blood than the control group (66.73 ng/ml vs 54.17 ng/ml, P<0.05); compared with the low-exposure group (65.39 ng/ml), the high-exposure group showed an increase in the protein expression of APP in lymphocytes in peripheral blood (67.22 ng/ml), but there was no significant difference between these two groups (P>0.05). The multivariate logistic regression analysis showed that with reference to the control group, low aluminium exposure (OR=1.86, 95% CI 1.67~3.52)and high aluminium exposure (OR=2.98, 95% CI 1.97~4.15)were risk factors for a reduced methylation rate of the promoter region of APP gene.
  
  
  CONCLUSIONS
  Reduced methylation of the promoter region of APP gene may be associated with increased serum aluminium level, and downregulated methylation of the promoter region of APP gene may accelerate APP gene transcription.
authors: Department of Geriatrics, The First Hospital of Shanxi Medical University, Taiyuan 030001, China.
authors: X J
authors: XJ
authors: Yang
authors: Y Z
authors: YZ
authors: Yuan
authors: Q
authors: Q
authors: Niu
mesh_terms: D000535:Aluminum; D016564:Amyloid beta-Protein Precursor; D004572:Electrolysis; D006801:Humans; D008745:Methylation; D009784:Occupational Diseases
chemical_list: D016564:Amyloid beta-Protein Precursor; D000535:Aluminum