A meta-analysis on CSF neurogranin levels for the diagnosis of Alzheimer's disease and mild cognitive impairment.

Abstract

Neurogranin is a postsynaptic protein involved in long-term potentiation and synaptic plasticity. Recent studies have shown increased neurogranin levels in the cerebrospinal fluid of Alzheimer's disease patients, and in patients with mild cognitive impairment. We searched the online databases for studies on neurogranin cerebrospinal fluid levels in Alzheimer's disease, mild cognitive impairment and other neurodegenerative disorders, and we did a meta-analysis to clarify whether this can be a reliable biomarker for the diagnosis of Alzheimer's disease, and the discrimination from other disorders. The present meta-analysis showed that neurogranin CSF levels are significantly higher in AD patients compared to NC [SMD: 268.26, 95% CI (143.47, 393.04), Z = 4.21, P = 0.0001], MCI [SMD: 23.45 (15.97, 30.92), Z = 6.15, P < 0.00001], FTD [SMD: 1.91 (0.92, 2.89), Z = 3.80, P < 0.0001], but no significant difference was found between AD and LBD [SMD: 138.51 (- 14.92, 291.95), Z = 1.77, P = 0.08]. Comparison of stable MCI and MCI that progressed to AD showed significantly higher levels in the CSF of MCI patients who progressed to AD, compared to stable MCI patients [SMD: 230.84 (12.54, 449.14), Z = 2.07, P = 0.04]. Neurogranin can also be a useful biomarker for the differentiation MCI and NC, but not between MCI and FTD or LBD. Neurogranin could be added to the panel of existing biomarkers for a more accurate diagnosis and progress of AD and assessment of underlying pathological changes in the brain.