ABSTRACT
Objective To observe the effects of short-term withdrawal of thyroxine on lipid level and the protective effect of atorvastatin.Methods The study included 60 rabbits which were randomly divided into treatment experiment group 1 (near-total thyroidectomy + 131 I ablative therapy),treatment experiment group 2 (near-total thyroidectomy + 131I ablative therapy + Atorvastatin intervention) and control group(sham thyroidectomy).Compared the thyroid functions and lipid levels among different groups at the points of before surgery.three weeks after surgery and five weeks after surgery.Results (1) Compared to before surgery,the thyroid function at the points of three weeks and five weeks after surgery were obvious reduced both in treatment group.(2) The leves of TG,TC,LDL-C in EG1 were increased gradually with the extension of time after surgery.Compared with the point of before surgery,the level of HDL-C at the point of five weeks after surgery was significantly declined in EG1.Compared with the point of before surgery,the level of TG at the ponts of three weeks and five weeks after surgery was significantly declined in EG2.Compared with the point of before surgery,the level of LDL-C at the point of three weeks after surgery was significantly declined in EG2.Conclusions (1) Short-term hypothyroidism can increase the levels of TG,TC,LDL-C in plasma.(2) Atorvastatin can maintain the stability of blood lipids during Short-term hypothyroidism.
ABSTRACT
BACKGROUND AND OBJECTIVES: The relationship between short-term hypothyroidism due to levothyroxine (LT4) withdrawal for radioactive iodine (RI) therapy in patients with differentiated thyroid cancer (DTC) and risk of cardiovascular disease is not clear. In this study, we evaluated the impact of short-term overt hypothyroidism on lipid profiles and cardiovascular parameters in patients with DTC. MATERIALS AND METHODS: We recruited 195 patients with DTC who were preparing RI therapy from March 2008 to February 2012. We analyzed the effect of thyroid stimulating hormone (TSH) level on the clinical, biochemical, and cardiovascular risk markers at the end of LT4 withdrawal protocol (P2). RESULTS: After LT4 withdrawal (P2), TSH and total cholesterol (TC) levels were significantly increased (p121 microIU/mL), all values did not have a statistical significant meaning except Apo A1. CONCLUSION: Short-term hypothyroidism induced worsening of lipid metabolic parameters, but not enough to induce the cardiovascular risk in patients with thyroid cancer.
Subject(s)
Humans , Alanine Transaminase , Apolipoprotein A-I , Apolipoproteins , Apolipoproteins B , Aspartate Aminotransferases , Bilirubin , Body Mass Index , C-Reactive Protein , Cardiovascular Diseases , Cholesterol , Cohort Studies , Cystatin C , Diabetes Mellitus , Homocysteine , Hypertension , Hypothyroidism , Iodine , Lipoprotein(a) , Reference Values , Thyroid Neoplasms , Thyrotropin , Thyroxine , Triglycerides , Uric AcidABSTRACT
PURPOSE: The incidence of differentiated thyroid cancer is increasing in young adults and females in Korea. Some of them experience short-term hypothyroidism in preparation for radioiodine (RAI) therapy, which can have a deleterious effect on the cardiovascular system. However, it is not clear if short-term hypothyroidism induces endothelial dysfunction in patients with low cardiovascular risk. Therefore, the aim of this study was to investigate whether short-term hypothyroidism is associated with endothelial dysfunction in patients with low cardiovascular risk. MATERIALS AND METHODS: To evaluate the effect of short-term hypothyroidism on endothelial function in this group, we recruited fifteen female patients with low cardiovascular risk. We analyzed clinical, biochemical, and cardiovascular parameters at four time points: the last day on levothyroxine (LT4) at their usual thyroid-stimulating hormone (TSH)-suppressive doses (P1), 7 days (P2) & 4 weeks (P3) after withdrawal of LT4, and 8 weeks (P4) after replacement of the previous dose of LT4. A high resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperemia, and after sublingual nitroglycerin. RESULTS: During short-term hypothyroidism (P3), serum concentrations of total cholesterol and low-density lipoprotein (LDL)-cholesterol were increased (p < 0.001 for each period). In spite of having worsened lipid states, serum high sensitivity C-reactive protein or flow-mediated vasodilatation, which is one of the surrogate markers of the endothelial function, did not change during short-term hypothyroidism. CONCLUSION: Short-term hypothyroidism induced worsening of metabolic parameters, but not enough to induce the endothelial dysfunction in patients with low cardiovascular risk.