Sigal, Gilbert A.
Tavoni, Thauany M.
Silva, Bruna M. O.
Brandao, Lenine G.
Baracat, Edmund C.
Maranhao, Raul C.
Total Authors: 7
 Univ Sao Paulo, Heart Inst InCor, Lipid Metab Lab, Med Sch Hosp, Sao Paulo - Brazil
 Univ Sao Paulo, Heart Inst InCor, Clin Cardiol Div, Med Sch Hosp, Sao Paulo - Brazil
 Univ Sao Paulo, Dept Head & Neck Surg, Med Sch Hosp, Sao Paulo - Brazil
 Univ Sao Paulo, Med Sch Hosp, Dept Obstet & Gynecol, Sao Paulo - Brazil
 Univ Sao Paulo, Fac Pharmaceut Sci, Sao Paulo - Brazil
Total Affiliations: 5
FRONTIERS IN ENDOCRINOLOGY;
APR 2 2020.
Web of Science Citations:
Purpose: Lipid metabolism has been poorly explored in subclinical hyperthyroidism. The aim was to examine the effects of exogenous subclinical hyperthyroidism in women under levothyroxine treatment upon plasma lipids and aspects of HDL metabolism. Methodology: Ten women were studied in euthyroidism and again in exogenous subclinical hyperthyroidism. Thyroid function tests and plasma lipids were studied. Results: HDL-cholesterol (increased 21.6%, p = 0.0004), unesterified cholesterol (increased 12.3%, p = 0.04) and Lp(a) (increased 33,3%, P = 0.02) plasma concentrations were higher in subclinical hyperthyroidism compared to euthyroidism, but total cholesterol, LDL, non-HDL cholesterol, triglycerides, apo A-I, apo B were unchanged. PON1 activity (decreased 75%, p = 0.0006) was lower in subclinical hyperthyroidism. There were no changes in HDL particle size, CETP and LCAT concentrations. The in vitro assay that estimates the lipid transfers to HDL showed that esterified cholesterol (increased 7.1%, p = 0.03), unesterified cholesterol (increased 7.8%, p = 0.02) and triglycerides (increased 6.8%, p = 0.006) transfers were higher in subclinical hyperthyroidism. There were no changes in phospholipid transfers to HDL in subclinical hyperthyroidism. Conclusions: Several alterations in the plasma lipid metabolism were observed in the subclinical hyperthyroidism state that highlight the importance of this aspect in the follow-up of those patients. The increase in HDL-C and in the transfer of unesterified and esterified cholesterol to HDL, an important anti-atherogenic HDL function are consistently protective for cardiovascular health. The increase in Lp(a) and the decrease in PON-1 activity that are important risk factors were documented here in subclinical hyperthyroidism and these results should be confirmed in larger studies due to great data variation but should not be neglected in the follow-up of those patients. (AU)