Plasma amyloid-beta (A beta) has long been investigated as a blood biomarker candidate for Cerebral Amyloid Angiopathy (CAA), however previous findings have been inconsistent which could be... Show morePlasma amyloid-beta (A beta) has long been investigated as a blood biomarker candidate for Cerebral Amyloid Angiopathy (CAA), however previous findings have been inconsistent which could be attributed to the use of less sensitive assays. This study investigates plasma A beta alterations between pre-symptomatic Dutch-type hereditary CAA (D-CAA) mutation-carriers (MC) and non-carriers (NC) using two A beta measurement platforms. Seventeen pre-symptomatic members of a D-CAA pedigree were assembled and followed up 3-4 years later (NC = 8; MC = 9). Plasma A beta 1-40 and A beta 1-42 were cross-sectionally and longitudinally analysed at baseline (T1) and follow-up (T2) and were found to be lower in MCs compared to NCs, cross-sectionally after adjusting for covariates, at both T1(A beta 1-40: p = 0.001; A beta 1-42: p = 0.0004) and T2 (A beta 1-40: p = 0.001; A beta 1-42: p = 0.016) employing the Single Molecule Array (Simoa) platform, however no significant differences were observed using the xMAP platform. Further, pairwise longitudinal analyses of plasma A beta 1-40 revealed decreased levels in MCs using data from the Simoa platform (p = 0.041) and pairwise longitudinal analyses of plasma A beta 1-42 revealed decreased levels in MCs using data from the xMAP platform (p = 0.041). Findings from the Simoa platform suggest that plasma A beta may add value to a panel of biomarkers for the diagnosis of pre-symptomatic CAA, however, further validation studies in larger sample sets are required. Show less
According to the amyloid cascade hypothesis, accumulation of beta-amyloid (Aβ) peptides initiates the pathological cascade in Alzheimer's disease (AD). Early in the disease process, before clinical... Show moreAccording to the amyloid cascade hypothesis, accumulation of beta-amyloid (Aβ) peptides initiates the pathological cascade in Alzheimer's disease (AD). Early in the disease process, before clinical symptoms, an increase in Aβ concentrations leads to formation of toxic Aβ oligomers. These oligomers drive the neurodegeneration in AD brain. An important therapeutic strategy is to lower Aβ concentration in the CNS. Theoretically, this can prevent all subsequent pathological processes. Aβ is the final product of sequential proteolytic cleavages of the precursor protein APP. The drug effects on the individual pathways of APP processing are hard to predict, because these are regulated by a complex biochemical network. In this research, a 'systems pharmacology' approach was applied, integrating available knowledge of biology and pharmacology of system reactions into mathematical models. The APP-system-pharmacology-model provides important information about the APP processing pathways: (i) Aβ production inhibition leads to a relatively greater decrease in Aβ oligomers compared to monomers (ii) dissociation of oligomers contributes to the drug effect; (iii) Aβ42 is the major Aβ variant that contributes to the oligomer pool; (iv) inhibition of the enzyme GS stimulates alternative processing of APP by feedback. The APP-system-pharmacology-model can be of value in development of therapeutic interventions for AD. Show less
Dorresteijn, B.; Rotman, M.; Faber, D.; Schravesande, R.; Suidgeest, E.; Weerd, L. van der; ... ; Khattabi, M. el 2015
