Promising diagnostic accuracy of plasma GFAP

Glial fibrillary acidic protein (GFAP) in plasma accurately differentiated patients with Alzheimer’s disease (AD) from healthy controls and thus holds promise as a diagnostic biomarker for AD. This could be a non-invasive and cost-effective method to detect people at risk, early in the neuropathological cascade.

GFAP is an intermediate cytoskeletal filament protein of astrocytes and is regarded as a promising non-invasive biomarker for neurodegeneration. It has been shown that GFAP levels are increased in patients with AD compared with healthy controls. Dr Tandis Parvizi (Medical University of Vienna, Austria) examined the utility of GFAP as a biomarker along the AD continuum [1]. In a retrospective, cross-sectional study they included 185 subjects: 44 healthy controls and 141 patients with either subjective cognitive decline (SCD, n=18), mild cognitive impairment (MCI, n=63), or AD (n=60). Concentrations of GFAP in plasma and CSF were quantified using ultrasensitive single-molecule array (SIMOA).

The results showed a gradual increase of GFAP, with the lowest concentration in healthy controls and the highest in AD. The median concentration of GFAP in plasma was:

• healthy controls: 79 pg/mL (53.7–120.6);
• SCD: 111 pg/mL (71.0–154.0);
• MCI: 167.5 pg/mL (93.9–256.3);
• AD: 181.9 pg/mL (129.6–269.6).

Diagnostic discrimination between controls, MCI, and AD groups was good (P<0.001). Analysis of GFAP in plasma could further distinguish between groups with SCD and AD (P=0.01). To establish the value of these biomarkers for clinical diagnosis, the researchers constructed a diagnostic panel combining GFAP and neurofilament light chain (NfL) with well-known risk factors (age, sex, ApoE4 genotype). Results for distinguishing people with AD from healthy controls were promising, with an area under the curve (AUC) of 0.92. The AUC for distinguishing people with MCI and healthy controls was 0.82.

1. Parvizi T, et al. Promising diagnostic accuracy of Plasma GFAP within the AD continuum. OPR-121, EAN 2021 Virtual Congress, 19–22 June.

 

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Posted on 18 August 202125 March 2024