Table 2.
Association of plasma GFAP with 18F-SMBT-1 PET
| Regional SMBT-1 PET | Plasma Aβ1 - 42/Aβ1 - 40 | Aβ PET | Age | Sex | APOE ɛ4 carrier status | |
| β (p) | β (p) | β (p) | β (p) | β (p) | β (p) | |
| A. No covariates included | ||||||
| Supramarginal gyrus | 0.361 (0.002) | – | – | – | – | – |
| Posterior cingulate | 0.308 (0.009) | – | – | – | – | – |
| Lateral temporal | 0.299 (0.011) | – | – | – | – | – |
| Lateral occipital | 0.313 (0.008) | – | – | – | – | – |
| Superior parietal | 0.197 (0.099) | – | – | – | – | – |
| B. Inclusion of age, sex and APOE ɛ4 carrier status | ||||||
| Supramarginal gyrus | 0.331 (0.002) | – | – | 0.256 (0.010) | 0.408 (< 0.001) | 0.100 (0.341) |
| Posterior cingulate | 0.264 (0.013) | – | – | 0.270 (0.008) | 0.387 (< 0.001) | 0.129 (0.226) |
| Lateral temporal | 0.229 (0.029) | – | – | 0.281 (0.006) | 0.363 (< 0.001) | 0.145 (0.175) |
| Lateral occipital | 0.271 (0.017) | – | – | 0.233 (0.026) | 0.410 (< 0.001) | 0.115 (0.292) |
| Superior parietal | 0.200 (0.057) | – | – | 0.271 (0.010) | 0.386 (< 0.001) | 0.182 (0.084) |
| C. Inclusion of soluble Aβ, age, sex and APOE ɛ4 carrier status | ||||||
| Supramarginal gyrus | 0.323 (0.002) | –0.245 (0.014) | – | 0.215 (0.026) | 0.421 (<0.001) | 0.038 (0.715) |
| Posterior cingulate | 0.262 (0.011) | –0.253 (0.013) | – | 0.227 (0.022) | 0.402 (<0.001) | 0.063 (0.551) |
| Lateral temporal | 0.238 (0.019) | –0.264 (0.011) | – | 0.235 (0.018) | 0.379 (<0.001) | 0.073 (0.488) |
| Lateral occipital | 0.282 (0.010) | –0.266 (0.009) | – | 0.185 (0.068) | 0.428 (<0.001) | 0.041 (0.701) |
| Superior parietal | 0.229 (0.024) | –0.281 (0.007) | – | 0.219 (0.030) | 0.409 (<0.001) | 0.105 (0.310) |
| D. Inclusion of insoluble Aβ, age, sex and APOE ɛ4 carrier status | ||||||
| Supramarginal gyrus | 0.215 (0.038) | – | 0.365 (0.001) | 0.195 (0.038) | 0.425 (<0.001) | –0.023 (0.821) |
| Posterior cingulate | 0.190 (0.052) | – | 0.402 (<0.001) | 0.194 (0.039) | 0.418 (<0.001) | –0.026 (0.802) |
| Lateral temporal | 0.174 (0.068) | – | 0.415 (<0.001) | 0.199 (0.036) | 0.402 (<0.001) | –0.023 (0.829) |
| Lateral occipital | 0.142 (0.192) | – | 0.395 (<0.001) | 0.183 (0.060) | 0.421 (<0.001) | –0.015 (0.885) |
| Superior parietal | 0.149 (0.118) | – | 0.421 (<0.001) | 0.191 (0.046) | 0.420 (<0.001) | 0.004 (0.972) |
| E. Inclusion of soluble Aβ, insoluble Aβ, age, sex and APOE ɛ4 carrier status | ||||||
| Supramarginal gyrus | 0.226 (0.027) | –0.171 (0.079) | 0.310 (0.007) | 0.176 (0.058) | 0.431 (<0.001) | –0.048 (0.640) |
| Posterior cingulate | 0.198 (0.041) | –0.167 (0.088) | 0.351 (0.002) | 0.176 (0.060) | 0.424 (<0.001) | –0.050 (0.630) |
| Lateral temporal | 0.187 (0.048) | –0.172 (0.080) | 0.362 (0.001) | 0.179 (0.055) | 0.408 (<0.001) | –0.408 (0.644) |
| Lateral occipital | 0.170 (0.118) | –0.179 (0.074) | 0.332 (0.005) | 0.158 (1.00) | 0.432 (<0.001) | –0.044 (0.675) |
| Superior parietal | 0.175 (0.065) | –0.185 (0.064) | 0.362 (0.001) | 0.167 (0.076) | 0.430 (<0.001) | –0.022 (0.828) |
Linear regressions were used to perform analyses in all study participants (N = 71). Age, sex, APOE ɛ4 carrier status, soluble Aβ (plasma Aβ1 - 42/Aβ1 - 40 ratio), and insoluble Aβ (Aβ PET) were also added to the model as covariates. Natural log plasma GFAP values were used in the model to satisfy Shapiro-Wilk test of normality of the model residuals. ‘β’ represents the standardized coefficients and ‘p’ represents significance, with p < 0.05 considered significant (in bold). GFAP, glial fibrillary acidic protein; PET, positron emission tomography; 18F-SMBT-1, (S)-(2-methylpyrid-5-yl)-6-[(3-18F-fluoro-2-hydroxy)propoxy] quinoline.