AAIC: Turnover kinetics vary for different amyloid beta isoforms

(HealthDay)—Amyloid beta (Aβ)38 has faster turnover kinetics than Aβ40 and Aβ42, according to a study published online July 19 in Alzheimer's & Dementia to coincide with presentation at the annual Alzheimer's Association International Conference, held from July 16 to 20 in London.

Vitaliy Ovod, from the Washington University School of Medicine in St. Louis, and colleagues examined the turnover kinetics and concentrations of Aβ38, Aβ40, and Aβ42 in human plasma using the Stable Isotope Labeling Kinetics protocol.

The researchers found that the half-life of Aβ isoforms was approximately three hours in plasma. Compared with Aβ40 and Aβ42, Aβ38 demonstrated faster turnover kinetics. Amyloid positive participants had faster fractional turnover of Aβ42/Aβ40 and lower Aβ42 and Aβ42/Aβ40 concentrations.

"Faster turnover kinetics and lower Aβ42 concentrations in amyloid positive participants have been seen in prior cerebrospinal fluid Aβ studies, suggesting a blood-brain transportation mechanism of Aβ," the authors write. "The stability and sensitivity of plasma Aβ measurements [suggest] this may be a useful screening test for central nervous system amyloidosis."