Data di Pubblicazione:
2020
Citazione:
ANALYSIS OF LIPID AND PROTEIN OXIDATION STATUS IN HEART FAILURE PATIENTS / A.e. Martinez Fernandez ; supervisore: C. Banfi ; coordinator: G. Aldini. Università degli Studi di Milano, 2020 Jan 22. 32. ciclo, Anno Accademico 2019. [10.13130/martinez-fernandez-alma-estefania_phd2020-01-22].
Abstract:
Increasing body of evidence supports that oxidative stress is involved systolic and diastolic myocardial dysfunction in HF. Indeed, it has been well established an association between cardiac remodeling (hypertrophy, apoptosis or contractile dysfunction) and oxidative stress. Hence, the identification, quantification and fully characterization of oxidized biomolecules present in the plasma of HF patients can contribute to understand the mechanisms responsible for disease development but also as biological markers. However, the classic biomarkers of oxidative stress identified in HF do not provide thorough information but report about a general oxidative stress status. For a better understanding of the pathology of HF it is needed to unveil not only protein and lipid targets of oxidative damage but also the residues undergoing the modification within the protein and the structure of the oxidation products. Analysis of all of these oxPTMs and lipid peroxidation products by mass spectrometry is extremely challenging. Indeed, oxPTMs tend to occur randomly on a number of susceptible residues and proteins, making it extremely difficult to define all protein species. Along this project, plasma samples from HF patients belonging to different NYHA groups (from class I to class IV) have been employed to identify oxidized biomolecules as potential biomarkers of HF, and eventually subjected to several plasma prefractionation strategies combined with high-throughput untargeted and targeted mass spectrometry techniques. Consequently, part of this project has been focused on the study of oxidative modifications in human serum albumin (HSA), the most abundant protein in the circulatory system, associated with HF. HSA is involved in a wide range of biological functions and, due to its long half-life and high concentration in plasma, HSA is highly sensitive to undergo oxPTMs that may lead to its functional loss, thus contributing to the progression of HF. Taking advantage of the high abundance of HSA, we relatively quantified for the first time plasma levels of cysteinylated HSA (cys-HSA) and also levels of early glycated HSA (GA), and we observed a significant increase in HF patients with respect to the healthy subjects. A positive correlation between the levels of both isoforms and HF severity was highlighted whereas the abundance of total HSA showed a tendency to decrease when raising the severity degree of HF. For a deeper characterization of GA, we elucidated for the first time the early glycation pattern of HSA associated to HF by means of the newest generation of Tribrid MS instruments. Lys233 and lys525 were observed as the two most abundant glycated amino acids (79% and 13% respectively). Considering that further modifications of GA, such as rearrangement, oxidation, polymerization, and cleavage give rise to irreversible conjugates, called advanced glycation end products (AGEs), we also aimed to unveil the plasma advanced glycation pattern associated to HF. In this case, lys20, arg98, and lys402 emerged as the three most abundant carboxymethylated residues. Therefore, the results suggested that on one hand lys233 and lys525, and on the other lys20, arg98 and lys402, might represent the main potential therapeutic targets to reduce GA and AGE-HSA levels in HF patients, respectively. Besides the study of oxidized isoforms of HSA, we also tried to identify other less abundant advanced glycation and lipoxidation end products (AGEs and ALEs) in plasma by means of an enrichment strategy based on the ability of RAGE receptor to bind AGEs and ALEs. Due to the relevance of HSA in circulation, we have also evaluated the potential causal role of GA in the etiopathogenesis of HF. Hence, we pursued to evaluate the biological effects of GA on cardiac myo
Tipologia IRIS:
Tesi di dottorato
Keywords:
Heart failure; oxidative stress; oxidative damage; mass spectrometry; lipid peroxidation; glyated albumin; cysteinylated albumin; phospholipidome; AGEs; ALEs; plasma biomarker; gender differences; lipoxidation; cardiovascular disease
Elenco autori:
A.E. MARTINEZ FERNANDEZ
Link alla scheda completa: