Cerebrospinal fluid secretory Ca2+-dependent phospholipase A2 activity is increased in Alzheimer disease.

• BACKGROUND: The phospholipase A(2) (PLA2) family comprises multiple isoenzymes that vary in their physicochemical properties, cellular localizations, calcium sensitivities, and substrate specificities. Despite these differences, PLA2s share the ability to catalyze the synthesis of the precursors of the proinflammatory mediators. To investigate the potential of PLA2 as a biomarker in screening neuroinflammatory disorders in both clinical and research settings, we developed a PLA2 assay and determined the predominant types of PLA2 activity in cerebrospinal fluid (CSF). METHODS: We used liposomes composed of a fluorescent probe (bis-Bodipy FL C11-PC [1,2-bis-(4,4- difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-undecanoyl)-sn-glycero-3-phosphocholine]) and 1,2-dioleoyl-l-alpha-phosphatidylcholine as a substrate to measure CSF PLA2 activity in a 96-well microtiter plate format. We established the type of CSF PLA2 activity using type-specific inhibitors of PLA2. RESULTS: Using 5 microL CSF per assay, our PLA2 activity assay was reproducible with CVs <15% in 2 CSF samples and for recombinant secretory Ca(2+)-dependent PLA2 (sPLA2) in concentrations ranging from 0.25 to 1 micromol/L. This PLA2 assay allowed identification of sPLA2 activity in lumbar CSF from healthy individuals 20-77 years old that did not depend on either sex or age. Additionally, CSF sPLA2 activity was found to be increased (P = 0.0008) in patients with Alzheimer disease. CONCLUSIONS: Adult human CSF has sPLA2 activity that can be measured reliably with the assay described. This enzyme activity in the CSF is independent of both sex and age and might serve as a valuable biomarker of neuroinflammation, as we demonstrated in Alzheimer disease.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Psykiatri (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Psychiatry (hsv//eng)

Keyword

Adult

Aged

Alzheimer Disease

cerebrospinal fluid

enzymology

Biological Markers

cerebrospinal fluid

Calcium

physiology

Fluorescent Dyes

Humans

Middle Aged

Phosphatidylcholines

Phospholipases A2

Secretory

cerebrospinal fluid

Reference Values

Young Adult

Publication and Content Type

ref (subject category)

art (subject category)