RESUMO
ELND005 (scyllo-inositol), an endogenous inositol stereoisomer, is being investigated as an oral treatment for Alzheimer's disease (AD). Pharmacokinetics of ELND005 in plasma, cerebrospinal fluid (CSF), and brain was characterized in healthy young subjects. Eight men received 2000 mg ELND005 every 12 hours for 10 days. Plasma and CSF samples were collected at predetermined time points; ELND005 and amyloid-beta (Aß) fragments were measured by validated bioanalytical methods. Brain ELND005 levels, estimated by (1) H Magnetic Resonance Spectroscopy (MRS) scans were obtained from gray/white matter voxels at baseline and Day 8. ELND005 was well-tolerated during the study. During the apparent steady state, ELND005 plasma levels rapidly peaked at 39.8 µg/mL and decreased to an average trough concentration of 10.6 µg/mL at the end of the 12-hour dosing regimen. In contrast, CSF drug levels slowly peaked at 13.7 µg/mL and remained near the same level with average trough concentrations of 12.4 µg/mL. At Day 8, Brain ELND005 concentrations increased by 58-76% compared to baseline levels. The CSF concentrations achieved in this study were similar to those associated with efficacy in transgenic models of AD. No changes were detected in plasma and CSF levels of Aß fragments.
RESUMO
One of the most prolific chemical and anatomical imaging techniques of recent decades, magnetic resonance imaging (MRI), includes the ability to noninvasively assess neurochemical changes with magnetic resonance spectroscopy (MRS). Practical concerns are paramount in applying MRS, such as what the manufacturer provides with a routine MRI scanner, what methods are well tolerated by patients, and what has proved most diagnostically productive over a 25 year span of preliminary exploration of the technology. In this review, the authors explain the technical and neurochemical aspects of MRS and critically discuss its clinical neuroimaging applications.