1348
In the hippocampus of SAMP8 mice it has been found increases in A beta ( 42 ) levels , the principal constituent of amyloid plaques observed in AD , accompanied by both an increased expression of the cleaving enzyme BACE1 and a decreased expression of the degrading enzyme IDE .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None