Lipid metabolism in patients with hypothyroidism

• Grant number: 13/24197-8
• Support type: Regular Research Grants
• Duration: June 01, 2014 - May 31, 2016
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Lenine Garcia Brandão
• Grantee: Lenine Garcia Brandão
• Home Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Assoc. researchers: Gilbert Alexandre Sigal ; Marco Aurelio Vamondes Kulcsar ; Raul Cavalcante Maranhao

Abstract

Thyroid dysfunction leads to alterations in enzymes, receptors and other proteins that regulate the plasma lipid metabolism. Hypercholesterolemia present in hypothyroidism is the best known lipid metabolism alteration in thyroid dysfunction but the metabolism of quilomicrons, VLDL and HDL are also affected. Artificial lipid emulsions that mimic the lipoprotein composition may be used to evaluate several systems of the lipid transport in vitro and in vivo. The plasma kinetics of artificial lipidic emulsions is a practical tool for detection of alterations in the metabolism of triglycerides rich lipoproteins as VLDL and quilomicrons and LDL. Emulsions are used to investigate the in vitro lipid transfers that involve HDL and this has a great importance for the anti-atherogenic function of this lipoprotein. In a recent study it was demonstrated that, despite the plasma lipid profile was normal, the lipid transfers were alterated in subclinical hypothyroidism.The thyroid cancer treatment may be used as a model for evaluate the effects of thyroid hormone upon lipid metabolism. After total thyroidectomy patients remain a period of time in clinical hypothyroidism for about 6 weeks after surgery in order to screeninig for methastasis. After this period patients are maintained in subclinical hyperthyroidism by administration of supraphisiological doses of thyroid hormone. The objective of the study is to investigate in those patients the effects of hypothyroidism and subclinical hyperthyroidism upon the metabolism of triglyceride-rich lipoproteins and LDL as well the lipid transfers to HDL. The lipid profile and plasmatic apolipoproteins and the kinetics of artificial quilomicrons and of an emulsion that resemble LDL will be evaluated in the patients after some weeks, around 6 weeks, in hypothyroidism and again in subclinical hyperthyroidism. The transfers to HDL will be evaluated in vitro using artificial emulsions as donors of radioactive labeled lipids to HDL. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

SIGAL, GILBERT A.; TAVONI, THAUANY M.; SILVA, BRUNA M. O.; KHALIL-FILHO, ROBERTO; BRANDAO, LENINE G.; BARACAT, EDMUND C.; MARANHAO, RAUL C. Subclinical Hyperthyroidism: Status of the Cholesterol Transfers to HDL and Other Parameters Related to Lipoprotein Metabolism in Patients Submitted to Thyroidectomy for Thyroid Cancer. FRONTIERS IN ENDOCRINOLOGY, v. 11, APR 2 2020. Web of Science Citations: 1.