FP05-1 Contribution of the Immune System On Lipid Metabolism

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: FP05-Lipids: Regulation & Mechanism of Disease
Basic
Saturday, June 15, 2013: 11:00 AM-11:30 AM
Presentation Start Time: 11:00 AM
Room 133 (Moscone Center)

Poster Board SAT-727
Maria Moisidou*, Sevasti Karaliota, Styliani Ourailidou, Elisavet Kodela, Panagiotis Tsakanikas and Katia/Catherine P Karalis
Biomedical Research Foundation of the Academy of Athens, Athens, Greece
Food deprivation, to the extreme state of starvation, has serious impact upon several physiologic functions including immunity and metabolism. Emerging evidence supports the critical role of immune cells in the physiological changes associated with reduced food intake, with the main focus on amino acid deprivation and its downstream implications.  Although profound changes in lipid storage, with liver steatosis remaining the hallmark finding, are associated with starvation, data on the specific role of immune cells on lipid metabolism remains limited. The aim of this study was to elucidate the role of lymphocytes in starvation in mice, with an emphasis in the development of non-alcoholic fatty liver disease, NAFLD. For this purpose, we compared the responses of the lymphocyte-deficient rag1-/- and wild-type mice to starvation–induced NAFLD. To our surprise, macroscopically the livers of rag1-/- starved mice had normal appearance and minimal signs of lipid deposition were revealed by histology, in contrast to the abnormal appearance and the profound signs of steatosis in the wt mice. Genomic analysis of liver tissue from both groups identified significantly activated lipid oxidation pathway in the rag1-/- compared to the wt tissue. Interestingly, the adipocytes’ size of rag1-/- mice was also significantly smaller from that of the wt mice, indicating more efficient lipolysis in fat stores. In support of the above, indirect calorimetry analysis under normal feeding and refeeding states, showed significant decrease in the respiratory exchange ratio of the rag1-/- mice, as expected in association with more efficient lipid versus carbohydrate utilization. Similar experiments in the model organism Zebrafish, confirmed the differences in the lipid deposition in rag1-/- mutants in association with altered caloric intake. Our results provide evidence for the critical role of lymphocytes in starvation-induced hepatic lipid metabolism in experimental animal models. On-going studies aim to characterize the exact metabolic pathways and identify the particular factors involved in the lymphocyte-driven effects on lipid metabolism.

Nothing to Disclose: MM, SK, SO, EK, PT, KPK

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