Fig. 1
Blood thiamine diphosphate (TDP) levels correlate with brain glucose metabolism in patients with Alzheimer’s disease (AD). a Blood TDP levels were reduced, whereas thiamine monophosphate (TMP) and thiamine levels were not significantly altered in patients with AD as compared with those in control (Ctrl) subjects (TDP 85.04 ± 6.59 vs. 117.23 ± 4.83 nmol/L; TMP 16.02 ± 2.04 vs. 11.34 ± 2.27 nmol/L; thiamine 2.85 ± 0.62 vs. 3.37 ± 0.98 nmol/L, n = 14). b, c Representative Positron emission tomography with 2-[18F]fluoro-2-deoxy-d-glucose (FDG-PET) images of patient with AD (b) and control subject (c). d–g The standardized uptake value ratios (SUVRs) of representative brain regions in patients with AD were significantly reduced as compared with those in control subjects (d 1.10 ± 0.055 vs. 1.25 ± 0.030 in right midfrontal lobe; e 0.97 ± 0.044 vs. 1.16 ± 0.031 in right superior parietal lobe; f 0.95 ± 0.051 vs. 1.17 ± 0.028 in right midtemporal lobe; g 1.17 ± 0.044 vs. 1.20 ± 0.033 in left motor lobe; n = 14). h–k Correlations between SUVRs and blood TDP levels of representative brain regions in combined group. l–o Correlations between SUVRs and blood TDP levels of representative brain regions in patients with AD. R Right. * P < 0.05, ** P < 0.01, and *** P < 0.001