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ABSTRACT: Background
The significance of amyloid precursor protein (APP) and neuroinflammation in idiopathic normal pressure hydrocephalus (iNPH) and Alzheimer's disease (AD) is unknown.Objective
To investigate the role of soluble APP (sAPP) and amyloid beta (A?) isoforms, proinflammatory cytokines, and biomarkers of neuronal damage in the cerebrospinal fluid (CSF) in relation to brain biopsy A? and hyperphosphorylated tau (HP?) findings.Methods
The study population comprised 102 patients with possible NPH with cortical brain biopsies, ventricular and lumbar CSF samples, and DNA available. The final clinical diagnoses were: 53 iNPH (91% shunt-responders), 26 AD (10 mixed iNPH+AD), and 23 others. Biopsy samples were immunostained against A? and HP?. CSF levels of AD-related biomarkers (A?42, p-tau, total tau), non-AD-related A? isoforms (A?38, A?40), sAPP isoforms (sAPP?, sAPP?), proinflammatory cytokines (several interleukins (IL), interferon-gamma, monocyte chemoattractant protein-1, tumor necrosis factor-alpha) and biomarkers of neuronal damage (neurofilament light and myelin basic protein) were measured. All patients were genotyped for APOE.Results
Lumbar CSF levels of sAPP? were lower (p<0.05) in patients with shunt-responsive iNPH compared to non-iNPH patients. sAPP? showed a similar trend (p?=?0.06). CSF sAPP isoform levels showed no association to A? or HP? in the brain biopsy. Quantified A? load in the brain biopsy showed a negative correlation with CSF levels of A?42 in ventricular (r?=?-0.295, p?=?0.003) and lumbar (r?=?-0.356, p?=?0.01) samples, while the levels of A?38 and A?40 showed no correlation. CSF levels of proinflammatory cytokines and biomarkers of neuronal damage did not associate to the brain biopsy findings, diagnosis, or shunt response. Higher lumbar/ventricular CSF IL-8 ratios (p<0.001) were seen in lumbar samples collected after ventriculostomy compared to the samples collected before the procedure.Conclusions
The role of sAPP isoforms in iNPH seems to be independent from the amyloid cascade. No neuroinflammatory background was observed in iNPH or AD.
SUBMITTER: Pyykko OT
PROVIDER: S-EPMC3956805 | biostudies-literature | 2014
REPOSITORIES: biostudies-literature
Pyykkö Okko T OT Lumela Miikka M Rummukainen Jaana J Nerg Ossi O Seppälä Toni T TT Herukka Sanna-Kaisa SK Koivisto Anne M AM Alafuzoff Irina I Puli Lakshman L Savolainen Sakari S Soininen Hilkka H Jääskeläinen Juha E JE Hiltunen Mikko M Zetterberg Henrik H Leinonen Ville V
PloS one 20140317 3
<h4>Background</h4>The significance of amyloid precursor protein (APP) and neuroinflammation in idiopathic normal pressure hydrocephalus (iNPH) and Alzheimer's disease (AD) is unknown.<h4>Objective</h4>To investigate the role of soluble APP (sAPP) and amyloid beta (Aβ) isoforms, proinflammatory cytokines, and biomarkers of neuronal damage in the cerebrospinal fluid (CSF) in relation to brain biopsy Aβ and hyperphosphorylated tau (HPτ) findings.<h4>Methods</h4>The study population comprised 102 p ...[more]