Neuroinflammation in Lyme neuroborreliosis affects amyloid metabolism.
BACKGROUND
The metabolism of amyloid precursor protein (APP) and beta-amyloid (Abeta) is widely studied in Alzheimer's disease, where Abeta deposition and plaque development are essential components of the pathogenesis. However, the physiological role of amyloid in the adult nervous system remains largely unknown. We have previously found altered cerebral amyloid metabolism in other neuroinflammatory conditions. To further elucidate this, we investigated amyloid metabolism in patients with Lyme neuroborreliosis (LNB).


METHODS
The first part of the study was a cross-sectional cohort study in 61 patients with acute facial palsy (19 with LNB and 42 with idiopathic facial paresis, Bell's palsy) and 22 healthy controls. CSF was analysed for the beta-amyloid peptides Abeta38, Abeta40 and Abeta42, and the amyloid precursor protein (APP) isoforms alpha-sAPP and beta-sAPP. CSF total-tau (T-tau), phosphorylated tau (P-tau) and neurofilament protein (NFL) were measured to monitor neural cell damage. The second part of the study was a prospective cohort-study in 26 LNB patients undergoing consecutive lumbar punctures before and after antibiotic treatment to study time-dependent dynamics of the biomarkers.


RESULTS
In the cross-sectional study, LNB patients had lower levels of CSF alpha-sAPP, beta-sAPP and P-tau, and higher levels of CSF NFL than healthy controls and patients with Bell's palsy. In the prospective study, LNB patients had low levels of CSF alpha-sAPP, beta-sAPP and P-tau at baseline, which all increased towards normal at follow-up.


CONCLUSIONS
Amyloid metabolism is altered in LNB. CSF levels of alpha-sAPP, beta-sAPP and P-tau are decreased in acute infection and increase after treatment. In combination with earlier findings in multiple sclerosis, cerebral SLE and HIV with cerebral engagement, this points to an influence of neuroinflammation on amyloid metabolism.
Mattsson
Niklas
N
Clinical Neurochemistry Laboratory, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Mölndal, Sweden. niklas.mattsson@neuro.gu.se
Bremell
Daniel
D
Anckarsäter
Rolf
R
Blennow
Kaj
K
Anckarsäter
Henrik
H
Zetterberg
Henrik
H
Hagberg
Lars
L
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid / Q000378:metabolism*; D015415:Biomarkers / Q000134:cerebrospinal fluid / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020852:Lyme Neuroborreliosis / Q000134:cerebrospinal fluid / Q000276:immunology* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015213:Neuroimmunomodulation / Q000502:physiology*; D011446:Prospective Studies; D055815:Young Adult
D016229:Amyloid beta-Peptides; D015415:Biomarkers