Significant reduction of elevated serum lipoprotein(a) concentrations during levo-thyroxine-replacement therapy in a hypothyroid patient.

In a number of previous studies investigators have reported the effect of the thyroid status on the changes of the serum lipoprotein concentrations, whereas reports on serum Lp(a) concentrations have been limited and the results are controversial. Recently, we encountered a hypothyroid patient with elevated serum Lp(a) concentrations in whom serial measurements of serum Lp(a) concentration were performed during the hormone replacement therapy. Our observation on this patient is of particular interest: the serum Lp(a) concentrations tended to continue to decrease even after 1 year 5 months, suggesting that the effects of thyroid hormone on the serum Lp(a) levels may continue for much longer than those on the serum LDL-C. Our findings may suggest a possible role of this hormone in the regulation of Lp(a) metabolism. Together with the recent reports indicating that a thyroid hormone analogue lowered serum Lp(a) levels, our observation may also pave the way for the development of Lp(a)-lowering agents.