It is suggested that Alzheimer’s disease (AD) is caused by an imbalance between production, degradation and clearance of the amyloid-β (Aβ) protein. This imbalance leads to aggregation of Aβ and tau proteins and neurodegeneration in the brain. Today there is increasing evidence that the balance between the protease cathepsin B and the protease inhibitor cystatin C affects the tendency for Aβ to aggregate. The primary aim of this thesis was to investigate Aβ, cystatin C and cathepsin B levels in blood and cerebro-spinal fluid (CSF) in relation to the risk of AD. Studies I & II were based on the re-examinations of participants, at ages 70 and 77, in the Uppsala Longitudinal Study of Adult Men (ULSAM), a community-based prospective study initiated in 1970 (participants then being 50 years of age). In ULSAM, low plasma Aβ1-40 (Study I) and low serum cystatin C levels (Study II) were associated with a higher risk of AD. Studies III & IV were based on a cross-sectional sample of people with AD, mild cognitive impairment and healthy controls, recruited at three Swedish Memory Disorder units: Uppsala University Hospital, Uppsala, Skåne University Hospital, Malmö, and Karolinska University Hospital, Huddinge, Stockholm. In Study III, CSF cystatin C levels were positively correlated with both Aβ1-42 and tau levels. In Study IV, individuals with AD had higher mean plasma cathepsin B levels than healthy controls. In conclusion, low plasma Aβ1-40 and low serum cystatin C levels may precede clinically manifest AD in elderly men, cystatin C levels are positively correlated with Aβ1-42 and tau levels in CSF, and mean plasma cathepsin B levels are higher in people with AD compared to healthy controls. In addition to Aβ1-42 and tau levels in CSF, Aβ1-40, cystatin C and cathepsin B levels in blood may reflect the risk of AD.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-132175 |
| Date | January 2010 |
| Creators | Sundelöf, Johan |
| Publisher | Uppsala universitet, Geriatrik, Uppsala : Acta Universitatis Upsaliensis |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Doctoral thesis, comprehensive summary, info:eu-repo/semantics/doctoralThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, 1651-6206 ; 626 |
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