Developments on metallomic and proteominc strategies for early diagnosis of alzheirmer’s disease

Resumo

Alzheimer's disease (AD) is considered the new epidemic of the 21st century because of the increase on the year’s life expectancy which generates a remarkable increase of patients suffering this pathology. Etiology of AD is still unknown, but it is well-known that there are several factors related to AD. Regarding treatments, there is no medication that recovers patients, although there are available several drugs that diminish patient deterioration which are applied at advanced stages of the disease. Therefore, the knowledge of the behavior of this disease in the early stages is a goal in biomedical research. There are several studies that compare healthy people with patients who suffer AD but currently these studies are focused on knowing the evolution of the disease, that is, in studying the differences between an early stage such as mild cognitive impairment (MCI) and AD. The objective of this thesis has been focused on optimizing several techniques (multi-element analysis and proteomics) for searching potential biomarkers for an early AD diagnosis. The two first chapters have been devoted to the optimization of methods for the determination of several elements, which led to successful results (good precision and accuracy). The developed techniques differ in the sample introduction mode in ICP-MS, but both share short analysis time for assessing simultaneously several elements, and the use of very small sample volume. The first technique consists of using paper as a support for serum samples (dried blood spot, DBS) followed to introduction in ICP-MS after laser ablation (LA-ICP-MS). The second technique is based on discrete sampling for ICP-MS. Both techniques require very small sample volumes, short analysis times, as well as minimum sample handling and sample conservation. In the second part of this thesis regarding proteomics, we have been able to find several proteins for differentiating three groups of population (healthy people, AD patients, and MCI patients). The study has been addressed qualitatively and quantitatively, and these preliminary results are first step for designing a panel of biomarkers. In a final chapter, LA conditions have been optimized for the determination of metals in the isoforms of two proteins [Serotransferrin (TRFE) and Keratin type II cytoskeletal 1 (K2C1)] after 2D electrophoresis. The current research is therefore a first step to study the differences between groups of patients suffering AD using elements and proteins as discriminating features, but also the levels of metals bound to proteins.