Alzheimer’s and Albumin-Amyloid Beta Complexes

MedicalResearch.com Interview with:
Keiichi Yamamoto, MD, PhD
Department of Geriatric Medicine and Neurology,
Osaka City University Graduate School of Medicine
Osaka, Japan.

MedicalResearch.com: What are the main findings of the study?

Answer: Aβ is normally bound to and transported by albumin in blood. We therefore hypothesized that decreased blood levels of Albumin-Aβ complexes may be associated with decreased Aβ removal from brain to blood, resulting in Aβ accumulation in the brain. This is the first study demonstrated that decreased serum level of albumin-Aβ complexes was strongly associated with a higher prevalence of Alzheimer’s disease (AD). This association was independent of age, sex, and ApoE4 allele. In addition, decreased serum level of albumin-Aβ complexes was correlated with decreased levels of Aβ42 in the CSF and increased levels of p-tau in the CSF, findings that have been shown to be associated with specific neuropathologic findings and AD progression.

MedicalResearch.com: Were any of the findings unexpected?

Answer: Initially, we measured the serum level of Albumin-Aβ complexes using a specific sandwich ELISA that employs anti-human Aβ C-terminal monoclonal antibody and anti-human albumin purified polyclonal antibody. But, we did not detect any signals.

Secondary, we employed anti-human Aβ N-terminal monoclonal antibody instead of C-terminal monoclonal antibody and detected some signals.

This might indicate that Aβ binds to albumin by its C-terminal domains.

MedicalResearch.com: What should clinicians and patients take away from your report?

Answer: This noninvasive and convenient novel method may be very useful for monitoring of the progression of AD. Moreover, these findings may be able to explain the mechanism how Aβ is accumulated in AD brain. Less binding ability of serum albumin to Aβ in AD patients may slower the clearance of Aβ from CNS.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Answer: The mechanism by which Aβ binds to albumin remains to be determined in this study. Further research is warranted to confirm the underlying mechanism.

 Citation:

Serum levels of albumin-amyloid beta complexes are decreased in Alzheimer’s disease.

Yamamoto K, Shimada H, Koh H, Ataka S, Miki T.
Department of Geriatric Medicine and Neurology, Osaka City University Graduate School of Medicine, Osaka, Japan.
Geriatr Gerontol Int. 2013 Sep 11. doi: 10.1111/ggi.12147. [Epub ahead of print]