Metabolic phenotyping of animal models of diet induced obesity and its complications
- Autores: Eugenia Carril Carvajal
- Directores de la Tesis: Francisco Javier Rupérez Pascualena (dir. tes.), Joanna Barbara Godzien (codir. tes.)
- Lectura: En la Universidad CEU San Pablo ( España ) en 2021
- Idioma: español
- Tribunal Calificador de la Tesis: Coral Barbas Arribas (presid.), Carolina Gonzalez-Riano (secret.), Maria Gema Medina Gomez (voc.), Alessia Ferrarini (voc.), Michal Ciborowski (voc.)
- Materias:
- Enlaces
- Tesis en acceso abierto en: Repositorio Institucional CEU
- Resumen
Obesity is the primary cause of insulin resistance that represents one of the main threats to global human health and is increasing every year. In the liver, obesity is manifested by the clinical disorder of the Non-Alcoholic Fatty Liver Disease (NAFLD) that is characterized by insulin resistance and accumulation of triglycerides (hepatic steatosis) Metabolomics or metabonomics is the study of the metabolic composition of a cell, tissue or biological fluid and the quantitative and multiparametric measurement of the response of a living being to some pathophysiological stimuli of genetic modification. Nowadays, metabolomics is focused on the resolution of biological challenges by only studying one single tissue. The global purpose of this project is to study through metabolomic a comprehensive approach to evaluating as much as possible the metabolic alterations associated with diet-induced obesity in different organs simultaneously. Also,to study one ofthe main complicationsof obesity: non-alcoholic steatohepatitis (NASH) and possible treatment. There are different dietary animal models relevant to mimic specific pathogenesis and metabolic disorders in the organism. Among the dietary patterns used in this thesis are theHigh Fat Diet (HFD) (to induce obesity) and Methionine Choline (MCD)diet (to induce NASH). Inthe present thesis,we introducethe term “Compartmentomics” as a new omics that focuson the study of metabolic changes caused by obesity (in this case) in the different compartments of the body and then give them a holistic interpretation.In Chapter 1 we expose results obtained from 8 different tissues under obesity conditions. The realnovelty ofthis chapter is the employed methodology that allowed us to better understand the metabolic impact of obesity in an organismandsupposesa new way of studying pathologies. Multiplatform study through LC-MS, CE-MS and GC-MS was carried out and specificannotations strategies for data from each platform were applied, including database query (CEU Mass Mediator), in-house databases built from standards, MS/MS experiments, and lipid annotation with their Kendrick ́s Mass Defect.
We found common trends in many of the significant metabolites (amino acids, short-chain organic acids, lysophospholipids) in plasma, kidney, heart and skeletal muscle. Diglycerides and triglyceridesvariations between obese and lean mice were similar between WATs but different from BAT. Moreover, the increase in lysophospholipids in plasma of obese mice seems more related to the increase in diglycerides in adipose tissue. Our results highlight the importance of the selection of the biospecimen according to the model under study, and our approach allows us to build a hypothesis about the metabolite flows between organs.Inside this chapter, one of the tissues (epidydimal White Adipose Tissue) was used to study and optimize an extraction methodology for TGs and oxylipins that were performed during my international mobilityat the “Adipose Tissue Department from the Institute of Physiology CAS from Prague, Czech Republic” in Prague. Results suggestthat there is an enrichment in stearic and oleic acid, a reduction in all PUFA and a noticeable increase in some of the significant lipid and proinflammatory mediators relatedespeciallyto 2-AG and Arachidonic acid respectively.In Chapter 2 one of the maincomplications related to obesity and insulin resistance is studied throughmetabolomics: Non-Alcoholic Steatohepatitis.In addition to the metabolic study of NASH and MCD diet, it was wanted to observe liver progression after a partial hepatectomy that is being used as therapy for liver regeneration in cirrhosis and some cancers. Compound putative identification was performed with CEU Mass Mediator. LC-MS/MS was employed to confirm part of the significant features, and a library of standards and a comprehensive list of compounds was compared in CE-MS.CE-MS has permitted to see changes in amino acid (proteinogenic and non-proteinogenic) and methylation pathways, whereas lipid metabolism (sphingolipid, phospholipid, neutral lipid, acylcarnitine, etc.) has been evaluated by means of LC-MS.Results show the great metabolic impact of NASH in the liver but are more remarkable the metabolic changes produced afterthePartial Hepatectomy. This study allowed us to elucidate a biological interpretation about metabolic changes due to NASH and also reinforces the previous idea of introducing Partial Hepatectomy as a futuretherapy for NASH and other liver complicationsand will help in the discovery and/or design of possible therapeutic strategies for liver regeneration.All thedata obtained in thestudiesof this thesis, after exhaustive work, allowed us to increase the information of the metabolic impactof obesity and its complicationsand obtain the widest metabolite coverage being able to compare results between samples as well as between treatments
