Profound Changes in Sex Hormone Levels during Cross-Sex Hormone Therapy of Transsexuals do not Alter Serum Cholesterol Acceptor Capacity.

INTRODUCTION

Men and postmenopausal women exhibit a higher risk for atherosclerosis than premenopausal women. These differences were often attributed to sex steroids, but the role of estrogen and testosterone in atherosclerosis are more complex than anticipated. Cross-sex hormone therapy of transsexuals is an interesting model, which has been used to study hormonal effects on serum lipid profile, insulin resistance, and body composition. However, studies on macrophage cholesterol efflux, the first step in reverse cholesterol transport, are not available.

AIM: The aim of this study was to evaluate the effect of cross-sex hormone therapy in transsexuals on the capacity of serum to accept cholesterol from macrophages.

METHODS

Cholesterol acceptor capacity (CAC) of serum from transsexuals before and after at least 6 months of hormone treatment was measured using macrophage tissue culture models.

MAIN OUTCOME MEASURES: CAC of serum using the human acute monocytic leukemia cell line (THP-1 cells).

RESULTS

Unexpectedly, the CAC of serum from male to female (MtF) transsexuals was not increased, but decreased after hormone therapy. Serum from female to male (FtM) transsexuals showed no changes in CAC.

CONCLUSIONS

Despite drastic changes in hormone status, no increase in CAC was detected in MtF patients, and no alteration in CAC was seen in FtM patients. These data further challenge the traditional view that estrogen and testosterone exert beneficial and detrimental effects, respectively, on lipoprotein metabolism and ultimately atherosclerosis.