Biomarcadores de lesão microvascular, de dislipidemia e micropartículas plaquetárias em idosos com e sem comprometimento cognitivo

Abstract

Alzheimers Disease (AD) is a multifactorial disease and its diagnosis is exclusively clinical, which makes the discovery of a specific, sensitive and reliable biomarker crucial for an early diagnosis. Considering the few therapeutic options, the finding of people with high potential for developing dementia is fundamental. Recent studies indicate that the assessment of microvascular brain damage may prove to be a sensitive tool for detecting early stages of AD. Furthermore, the microvascular pathology can be an important and specific therapeutic target, and once detected by biomarkers, this evaluation could be a helpful tool for diagnosis and assessment of the disease progression, as well as treatment efficacy. The objective of this study was to evaluate potential biomarkers, focusing on those specific for microvascular and platelet alterations in patients with Mild Cognitive Impairment (MCI) and AD, seeking to contribute to broaden the current knowledge on AD. This study assessed serum or plasma samples, looking for possible candidates biochemical markers for AD. In a group of 177 subjects, including those with AD (n=59), MCI (n=59), and elderly people without cognitive impairment (n=59), the following parameters were determined: (1) intercellular adhesion molecule-1 (ICAM-1); (2) homocysteine; (3) platelet microparticles; (4) conventional and non conventional lipid profile, and (5) apolipoprotein E (apoE) genotyping. The pooled analysis of data obtained in this study indicates that the elevation of sICAM-1 plasma levels, a biomarker of microvascular injury appear to be associated with the development of AD. Moreover, the frequency of allele 4 showed to be disproportionately elevated in patients with AD and MCI compared to the group of elderly without dementia. In line with previous studies, the mere presence of the allele 4 from Apo E is not sufficient for the AD development, which only increases the risk of AD, indicating that there are other important genetic and environmental factors in the development of the disease. Individuals from the control group have presented significantly increased levels of HDLc compared to those observed in DA and MCI patients. Concerning to the apolipoprotein profile of the three groups, apo B levels were significantly increased in the MCI group compared to the control and DA groups. Finally, plasma levels of homocysteine and platelet microparticles in the group with AD were not significantly different when compared to the levels observed for both control group and MCI.