Association between thyroid function and lipid profiles, apolipoproteins, and high-density lipoprotein function

Area of Science:

• Endocrinology
• Metabolic Research
• Cardiovascular Science

Background:

• Thyroid hormone plays a crucial role in regulating lipid metabolism.
• It influences plasma high-density lipoprotein cholesterol (HDL-C) levels and HDL metabolism pathways.

Purpose of the Study:

• To investigate the dynamic changes in lipids, apolipoproteins, and HDL function in response to acute thyroid function fluctuations.
• To assess the impact of thyroidectomy and radioactive iodine (RAI) treatment on these parameters.

Main Methods:

• Studied 27 differentiated thyroid carcinoma patients undergoing total thyroidectomy and RAI treatment.
• Measured plasma lipids, apolipoproteins, paraoxonase-1 activity, and cholesterol efflux at three time points: subclinical hyperthyroidism, overt hypothyroidism, and post-treatment recovery.

Main Results:

• Overt hypothyroidism significantly increased total cholesterol, triglycerides, LDL-C, apoB, and apoA-I/II ratio, which normalized with levothyroxine.
• HDL-C and apoE levels remained elevated, while paraoxonase-1 activity and cholesterol efflux decreased during hypothyroidism, with efflux remaining low post-treatment.

Conclusions:

• Acute changes in thyroid function dynamically alter plasma lipid concentrations and apolipoprotein levels.
• Thyroid function status significantly impacts HDL function, including cholesterol efflux capacity, with some alterations persisting after thyroid function normalization.