RESUMO
OBJECTIVE: Although Mediterranean diet is connected with longevity and lower rate of many disorders including Alzheimer's disease (AD), the effect of olive oil, which is the principal component of the Mediterranean diet, on fibrinolytic system related to AD and especially on plasminogen activator inhibitor-1 (PAI-1) and a2-antiplasmin in aged participants are not yet examined. This study was performed on 108 aged participants allocated into 5 groups: Mild Cognitive Impairment (MCI) (36) patients subjected to 1-year therapy with extra virgin olive oil (EVOO), MCI without therapy patients (26), MCI without therapy 1-year later patients (11), AD patients (30) and healthy individuals (16). Hypothesis/Purpose: To examine the effect of EVOO therapy on the fibrinolytic factors PAI-1 and a2-antiplasmin, on hallmarks of AD, tau and Aß amyloid fragments and on an oxidative stress biomarker, MDA in the serum of MCI patients aiming to be exploited as a future preventive therapy. RESULTS: Using ELISA method, the levels of both fibrinolytic factors PAI-1 and a2- antiplasmin in the serum of MCI patients were reduced notably in the EVOO treated patients versus the control group and were lower than those of all other groups. For better determination of AD from other pathological conditions the ratio Aß1-42/Aß1-40 was measured in serum of all participants. The more lessened the ratio is, the more cognitive impairment is observed in patients. The MCI group with one-year EVOO therapy displayed a ratio similar to this of healthy individuals. Moreover, patients with EVOO therapy showed decreased tau protein levels in comparison with all the other groups. The levels of the oxidative stress's biomarker, malondialdehyde (MDA) showed a significant decrease in MCI patients subjected to EVOO therapy revealing the involvement of the beneficial antioxidative properties of EVOO in the progression of AD. CONCLUSION: We demonstrated that EVOO therapy may prevent the risk of patients with MCI to progress to AD via decreasing fibrinolytic factors PAI-1 and a2 antiplasmin that reflecting in the diminution of the hallmarks proteins of AD, tau and Aß amyloid as well and in a biomarker of oxidative stress, MDA.