Tau plasma levels in subjective cognitive decline: Results from the DELCODE study

Area of Science:

• Neuroscience
• Biomarkers
• Neurodegenerative Diseases

Background:

• Elevated plasma tau levels are observed in Alzheimer's disease (AD) and mild cognitive impairment (MCI).
• The utility of plasma tau as an early biomarker in the pre-MCI stage of subjective cognitive decline (SCD) remains largely unexplored.

Purpose of the Study:

• To investigate whether plasma tau levels are elevated in individuals with subjective cognitive decline (SCD).
• To explore the correlation between plasma tau levels and cerebrospinal fluid (CSF) biomarkers in SCD patients.

Main Methods:

• Plasma tau levels were measured using ultra-sensitive single-molecule array (Simoa) technology in 111 SCD patients and 134 healthy controls.
• Cerebrospinal fluid (CSF) biomarkers, including Aβ42, tau, and p-tau181, were analyzed in a subgroup of 45 SCD patients.

Main Results:

• No significant difference in plasma tau levels was found between SCD patients (3.4 pg/ml) and healthy controls (3.6 pg/ml) after adjusting for age, gender, and education.
• Plasma tau levels did not correlate with CSF Aβ42, tau, or p-tau181 levels in the subgroup of SCD patients.

Conclusions:

• Plasma tau is not elevated in individuals with subjective cognitive decline (SCD).
• The lack of correlation between plasma and CSF tau suggests distinct factors influence tau levels in these biofluids, questioning plasma tau's utility as an early AD biomarker.