Date Published: June 1, 2018
Publisher: JKL International LLC
Author(s): Qiong Ding, Kitora Tanigawa, Jun Kaneko, Mamoru Totsuka, Yoshinori Katakura, Etsuko Imabayashi, Hiroshi Matsuda, Tatsuhiro Hisatsune.
In a previously reported double-blind, randomized controlled trial (RCT), we demonstrated that daily supplementation with anserine (750 mg) and carnosine (250 mg) improves brain blood flow and memory function in elderly people. Here, we conducted a sub-analysis of MRI data and test scores from the same RCT to determine whether anserine/carnosine supplementation specifically benefits elderly people carrying the APOE e4 allele, which is a risk gene for accelerated brain aging and for the onset of Alzheimer’s Disease. We collected data from 68 participants aged 65 years or older who received anserine/carnosine supplementation (ACS) or placebo for 12 months. Subjects were assessed at the start and end of the trial using several neuropsychological tests, including the Wechsler Memory Scale-Logical Memory (WMS-LM). We also collected two types of MRI data, arterial spin labeling (ASL) and diffusion tensor imaging (DTI) at the start and end of the trial. We found that ACS significantly preserved verbal memory (WMS-LM, F[1,65] = 4.2003, p = 0.0445) and blood flow at frontal areas of the brain (FWEcluster level, p < 0.001). Sub-analysis based on the APOE4 genotype showed a significant preservation of blood flow (p = 0.002, by ASL analysis) and white-matter microstructure (p = 0.003, by DTI analysis) at prefrontal areas in APOE4+ subjects in the active group, while there was no significant difference between APOE4- subjects in the active and placebo groups. The effect of ACS in preserving brain structure and function in elderly people carrying APOE4 should be verified by further studies.
Here, we showed that ACS suppresses age-related memory decline and alteration in brain blood flow, in line with previous observations [4,5,10]. However, a new finding in the present study is that ACS has stronger benefits for elderly people bearing the risk allele APOE4, as revealed by both ASL and DTI data. Brain blood flow was preserved in prefrontal areas of the brain in APOE4 carriers after 12 months of ACS. Although considerable research has gone into determining whether DHA can benefit APOE4 carriers, the issue is still in debate [38,39]. ACS is another promising candidate for protecting against the detrimental effect of APOE4 molecules on brain function and structure.