Apathy correlates with prefrontal amyloid beta deposition in Alzheimer’s Disease

11th World Congress of Biological Psychiatr

Apathy correlates with prefrontal amyloid β deposition in Alzheimer\u27s disease

Objective Neuropsychiatric symptoms affect many patients with Alzheimer\u27s disease (AD). (11C)Pittsburgh Compound-B (PIB) positron emission tomography (PET) has enabled the in vivo visualisation of brain amyloid-β (Aβ) deposition. This study exploratively investigated the correlation between brain Aβ deposition measured by (11C)PIB PET and neuropsychiatric symptoms in AD. \nMethods Participants were 28 patients (15 women, 13 men) with PIB-positive AD. Clinical assessments included Mini-Mental State Examination, Clinical Dementia Rating scale, neuropsychiatry inventory (NPI) and frontal assessment battery. All patients underwent three-dimensional T1-weighted MRI and (11C)PIB PET. The distribution volume ratio (DVR), an index of (11C)PIB retention and, thus, Aβ deposition, was estimated voxel by voxel from (11C)PIB PET data with partial volume correction. Voxel-based correlation analysis was performed to assess the relationships between DVR and each NPI subscale. Additionally, voxel-based analysis of covariance (ANCOVA) of the DVR images was performed between Patients with AD with and without each neuropsychiatric symptom. Voxel-based morphometry analysis of MRI was also performed. \nResults Apathy subscale was correlated with (11C)PIB retention in the bilateral frontal and right anterior cingulate. (11C)PIB retention was greater in the bilateral frontal cortex of patients with AD with apathy than those of without apathy. Overlapping areas between the two analyses were the bilateral orbitofrontal gyrus and left superior frontal gyrus. Other NPI subscales were not correlated with (11C)PIB retention. Voxel-based morphometry analysis of MRI showed no significant cluster of correlation between grey matter volume and NPI subscales. \nConclusions This study revealed that prefrontal Aβ deposition correlates with apathy

Distribution of D-3-aminoisobutyrate-pyruvate aminotransferase in the rat brain

BACKGROUND: D-3-aminoisobutyrate, an intermediary product of thymine, is converted to 2-methyl-3-oxopropanoate using pyruvate as an amino acceptor by D-3-aminoisobutyrate-pyruvate aminotransferase (D-AIB AT; EC 2.6.1.40). A large amount of D-AIB AT is distributed in the kidney and liver; however, small amounts are found in the brain. Recently, D-AIB AT was reported to metabolize asymmetric dimethylarginine (ADMA) in vivo and was suggested to be an important enzyme for nitric oxide metabolism because ADMA is a competitive inhibitor for nitric oxide synthase. In this study, we examined the distribution of D-AIB AT in the rat brain further to understand its role. We measured D-AIB AT mRNA and protein expression using quantitative RT-PCR and Western blotting, and monitored its distribution using immunohistochemical staining. RESULTS: D-AIB AT was distributed throughout the brain, with high expression in the cortex and hippocampus. Immunohistochemical staining revealed that D-AIB AT was highly expressed in the retrosplenial cortex and in hippocampal neurons. CONCLUSION: Our results suggest that D-AIB AT is distributed in the examined- just the regions and may play an important role there