Figure 2
Comparison of kynurenine pathway metabolites between NAL− and NAL+ participants, separately in males and females. Kynurenine pathway metabolite concentrations in serum were compared between participants (in A. Males and B. Females, separately) with neocortical amyloid-β load (NAL, assessed by the standard uptake value ratio observed via positron emission tomography using ligand 18F-florbetaben) <1.35 (NAL−) and ≥1.35 (NAL+) using linear models. Kynurenine (KYN), anthranilic acid (AA) and 3-hydroxykynurenine (3-HK) levels were significantly higher in NAL+ (N = 22) compared with NAL− (N = 46) female participants while 3-hydroxykynurenine (3-HK) levels were significantly lower in NAL+ (N = 13) compared with NAL− (N = 19) male participants. The line segment within each box plot represents the median within each box plot and error bars represent the range of the metabolite concentration for each group. *Represents p < 0.05, **represents p ≤ 0.01 and ***represents p < 0.0005; p values were obtained from variables transformed to the logarithmic scale for analyses to meet assumptions of the statistical test employed. TRP, tryptophan; KYNA, kynurenic acid; HAA, 3-hydroxyanthranilic acid; PA, picolinic acid; QA, quinolinic acid. (A) Serum metabolite concentrations in males. (B) Serum metabolite concentrations in females.
