Glial fibrillary acidic protein as a marker of axonal damage in chronic neuropat

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Glial fibrillary acidic protein as a marker of axonal damage in chronic

neuropathies.

Notturno F, Capasso M, DeLauretis A, Carpo M, Uncini A.

Department of Human Motor Sciences and Neuromuscular Diseases Unit, University

" G. d'Annunzio " and Institute of Aging (Ce.S.I.), Foundation University " G.

d'Annunzio, " via dei Vestini, 66013, Chieti-Pescara, Italy.

We evaluated serum glial fibrillary acidic protein (GFAP) levels by

enzyme-linked immunosorbent assay (ELISA) in controls (n = 30) and in patients

with chronic sensory-motor axonal neuropathy (CSMAN) (n = 30), chronic

inflammatory demyelinating polyneuropathy (CIDP) (n = 30), multifocal motor

neuropathy (MMN) (n = 30), and primary muscular spinal atrophy (PMSA) (n = 15).

GFAP levels, expressed as optical density, were increased in CSMAN (median =

1.05) compared to controls (median = 0.41; P < 0.05) and CIDP (median = 0.53, P

< 0.05). They were also increased in PMSA (median = 0.99) compared to controls

(P < 0.05) and MMN (median = 0.66; P < 0.05). To differentiate CSMAN from CIDP

and PMSA from MMN, we applied a cutoff of GFAP levels at 0.66, and we obtained

good sensitivity and specificity. In neuropathies, serum GFAP correlated with

summated sensory nerve action potential amplitudes (r = -0.57; P = 0.0006) and

disease severity (r = 0.37; P = 0.0011). Thus, we propose serum GFAP as a marker

of axonal damage and severity in chronic neuropathies.