PET tau and amyloid-β burden in mild Alzheimer's disease: divergent relationship with age, cognition and cerebrospinal fluid biomarkers
<strong>Background</strong> Combining PET amyloid-β and tau imaging may be critical for tracking disease progression in Alzheimer’s disease (AD). <strong>Objective</strong> We sought to characterize the relationship between amyloid-β and tau ligands as well as with other meas...
| Egile Nagusiak: | , , , , , , , , , , , |
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| Formatua: | Journal article |
| Argitaratua: |
IOS Press
2017
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| Gaia: | <strong>Background</strong> Combining PET amyloid-β and tau imaging may be critical for tracking disease progression in Alzheimer’s disease (AD). <strong>Objective</strong> We sought to characterize the relationship between amyloid-β and tau ligands as well as with other measures of pathology. <strong>Methods</strong> We conducted a multi-center observational study in early AD (MMSE >20) participants aged 50 to 85 years. The schedule included cognitive assessments (ADAS-Cog) and CSF measurement of Aβ and tau at baseline and 6 months; PET-CT imaging with amyloid-β ([18F]AV45) and tau ([18F]AV1451) ligands at baseline. <strong>Results</strong> 22 participants took part in the study with 20 completing its 6-month duration and 12 having both tau and amyloid PET. The PET biomarker analysis revealed a strong negative correlation between age and tau in multiple regions. Entorhinal cortex tau and age interacted significantly in terms of cognitive change over 6 months which may have been to older participants deteriorating faster despite lower levels of cortical tau. Cortical amyloid-β associated with entorhinal cortex tau while CSF tau/Aβ ratio correlated strongly with cortical tau but not amyloid-β. <strong>Conclusion</strong> The negative relationship between age and cortical tau whereby younger patients with mild AD had relatively greater tau burden is potentially important. It suggests that younger-age onset AD may be primarily driven by tau pathology while AD developing later may depend on a multitude of pathological mechanisms. These data also suggest that PET-tau performs better than PET-amyloid in predicting the best validated AD diagnostic marker – the CSF total tau/Aβratio. |
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