Serum Levels of Glial Fibrillary Acidic Protein Association with Cognitive Impairment and Type 2 Diabetes.

BACKGROUND: Peripheral biomarkers associated with neurocognitive disorders (NCD) have been evaluated in an attempt to improve diagnosis and early detection and potentially even prevent them. Along with increasing age, type 2 diabetes (T2D) increases the risk of central nervous system disorders and cognitive impairment due to the loss of synaptic function. Central damage triggers an astroglial response, increasing the expression of glial fibrillary acidic protein (GFAP), which can be found peripherally when the blood-brain barrier is compromised. AIM OF THE STUDY: To evaluate the value of GFAP as a peripheral biomarker of central dysfunction. METHODS: Serum levels of GFAP were compared between cases of NCD (n = 69) and age-matched controls (n = 69), analyzing the influence of diabetes as contributing factor. RESULTS: We found higher levels of serum GFAP in subjects with NCD compared with the control group (p <0.0001). The receiver operating characteristic (ROC) curve using the GFAP levels showed 65.22% sensitivity and 71.01% specificity (AUC = 0.7608), indicating good performance in the classification of controls and NCD patients. Logistic regression indicated a positive predictive power of 67.50% considering T2D status; adding GFAP levels, the predictive power rises to 71.93%. GFAP levels and T2D could be considered good predictors of NCD risk. CONCLUSIONS: Our findings open the possibility that peripheral GFAP could be used as an objective measurement related, under certain conditions, to central damage; thereby serving as a follow-up marker to refer diabetic patients for appropriate neurological evaluation, which could offer a low cost, minimally invasive strategy to improve the assessment of cognitive affectation and subsequent treatment.