Journal of Alzheimer's Disease - Volume 15, issue 1

Authors: Wahjoepramono, Eka J. | Wijaya, Linda K. | Taddei, Kevin | Martins, Georgia | Howard, Matthew | de Ruyck, Karl | Bates, Kristyn | Dhaliwal, Satvinder S. | Verdile, Giuseppe | Carruthers, Malcolm | Martins, Ralph N.

Article Type: Research Article

Abstract: The effect of testosterone on the levels of the Alzheimer's disease amyloid-β peptide (Aβ) was investigated in guinea pigs. Castrated guinea pigs (GPX) were administered testosterone at two different dosages, following which plasma and cerebrospinal fluid (CSF) Aβ40 levels were measured. Plasma Aβ40 levels were reduced in GPX in the early stages of low-dose testosterone treatment, whereas CSF Aβ40 levels were only reduced by the time circulating testosterone had returned to untreated GPX levels. The supraphysiological testosterone dose did not reduce CSF Aβ40 levels significantly until circulating testosterone was back to uncastrated levels, whereas plasma Aβ40 …levels significantly increased over time in these animals. These results indicate that the extent of testosterone-induced changes to Aβ40 levels and their response rates depend on both the tissue examined and testosterone dosage. Show more

Keywords: Aging, Alzheimer's disease, amyloid-β, castration, cerebrospinal fluid, guinea pig, testosterone

DOI: 10.3233/JAD-2008-15111

Citation: Journal of Alzheimer's Disease, vol. 15, no. 1, pp. 129-137, 2008

Authors: Leuba, Geneviève | Savioz, Armand | Vernay, André | Carnal, Béatrice | Kraftsik, Rudolf | Tardif, Eric | Riederer, Irène | Riederer, Béat Michel

Article Type: Research Article

Abstract: We investigated how synaptic plasticity is related to the neurodegeneration process in the human dorsolateral prefrontal cortex. Pre- and postsynaptic proteins of Brodmann's area 9 from patients with Alzheimer's disease (AD) and age-matched controls were quantified by immunohistochemical methods and Western blots. The main finding was a significant increase in the expression of postsynaptic density protein PSD-95 in AD brains, revealed on both sections and immunoblots, while the expression of spinophilin, associated to spines, remained quantitatively unchanged despite qualitative changes with age and disease. Presynaptic protein α-synuclein indicated an increased immunohistochemical level, while synaptophysin remained unchanged. MAP2, a somatodendritic microtubule …protein, as well as AD markers such as amyloid-β protein and phosphorylated protein tau showed an increased expression on immunosections in AD. Altogether these changes suggest neuritic and synaptic reorganization in the process of AD. In particular, the significant increase in PSD-95 expression suggests a change in NMDA receptors trafficking and may represent a novel marker of functional significance for the disease. Show more

Keywords: Aging, Alzheimer, frontal cortex, MAP2, plasticity, PSD-95, spinophilin, synapses, synaptophysin, α-synuclein

DOI: 10.3233/JAD-2008-15112

Citation: Journal of Alzheimer's Disease, vol. 15, no. 1, pp. 139-151, 2008

Article Type: Announcement

DOI: 10.3233/JAD-2008-15113

Citation: Journal of Alzheimer's Disease, vol. 15, no. 1, pp. 153-154, 2008