| 1. |
- Laitera, Tiina, et al.
(författare)
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Increased gamma-Secretase Activity in Idiopathic Normal Pressure Hydrocephalus Patients with beta-Amyloid Pathology
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:4, s. e93717-
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Tidskriftsartikel (refereegranskat)abstract
- The potential similarity between the brain pathology of idiopathic normal pressure hydrocephalus (iNPH) and Alzheimer disease (AD) is intriguing and thus further studies focusing on the underlying molecular mechanisms may offer valuable information for differential diagnostics and the development of treatments for iNPH. Here, we investigated beta- and gamma-secretase activities in relation to amyloid-beta (A beta) pathology in the brain tissue samples collected from iNPH and AD patients. beta- and gamma-secretase activities were measured from the frontal cortical biopsies of 26 patients with suspected iNPH as well as post-mortem tissue samples from the inferior temporal cortex of 74 AD patients and eight subjects without neurofibrillary pathology. In iNPH samples with detectable A beta plaques, gamma-secretase activity was significantly increased (similar to 1.6-fold) when compared to iNPH samples without A beta plaques (p=0.009). In the AD samples, statistically significant differences in the gamma-secretase activity were not observed with respect to disease severity (mild, moderate and severe AD according to neurofibrillary pathology). Conversely, beta-secretase activity was unaltered in iNPH samples with or without A beta plaques, while it was significantly increased in relation to disease severity in the AD patients. These results show for the first time increased gamma-secretase but not b-secretase activity in the biopsy samples from the frontal cortex of iNPH patients with AD-like A beta pathology. Conversely, the opposite was observed in these secretase activities in AD patients with respect to neurofibrillary pathology. Despite the resemblances in the A beta pathology, iNPH and AD patients appear to have marked differences in the cellular mechanisms responsible for the production of A beta.
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| 2. |
- Laitera, Tiina, et al.
(författare)
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The Expression of Transthyretin and Amyloid-beta Protein Precursor is Altered in the Brain of Idiopathic Normal Pressure Hydrocephalus Patients
- 2015
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 48:4, s. 959-968
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Tidskriftsartikel (refereegranskat)abstract
- Background: Idiopathic normal pressure hydrocephalus (iNPH) is a dementing condition in which Alzheimer's disease (AD)related amyloid-beta (A beta) plaques are frequently observed in the neocortex. iNPH patients with prominent A beta pathology show AD-related alterations in amyloid-beta protein precursor (A beta PP) processing resulting from increased gamma-secretase activity. Objectives: Our goal was to assess potential alterations in the global gene expression profile in the brain of iNPH patients as compared to non-demented controls and to evaluate the levels of the identified targets in the cerebrospinal fluid (CSF) of iNPH patients. Methods: The genome-wide expression profile of similar to 35,000 probes was assessed in the RNA samples obtained from 22 iNPH patients and eight non-demented control subjects using a microarray chip. The soluble levels of sA beta PP alpha, sA beta PP beta, and transthyretin (TTR) were measured from the CSF of 102 iNPH patients using ELISA. Results: After correcting the results for multiple testing, significant differences in the expression of TTR and A beta PP were observed between iNPH and control subjects. The mRNA levels of TTR were on average 17-fold lower in iNPH samples compared to control samples. Conversely, the expression level of A beta PP was on average three times higher in iNPH samples as compared to control samples. Interestingly, the expression of beta-secretase (ADAM10) was also increased in iNPH patients. In the lumbar CSF samples, soluble TTR levels showed a significant positive correlation with sA beta PP alpha and sA beta PP beta, but TTR levels did not predict the brain pathology or the shunt response. Conclusions: These findings suggest differences in the expression profile of key factors involved in AD-related cellular events in the brain of iNPH patients.
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