Application of aromatase inhibitors in treatment of male infertility

The causes of male infertility are diversified,and the unknown etiology of infertility is called idiopathic infertility.The patients with idiopathic infertility often present with low testosterone level and high estradiol level in serum and impaired spermatogenesis.The aromatase plays a key role in converting testosterone to estradiol.Aromatase inhibitors,such as letrozole,have the effects to inhibit the activity of aromatase.They decrease estradiol level and increase testosterone and gonadotropin levels and the ratio of T/E2.Therefore the spermatogenesis and semen parameters could be improved after aromatase inhibitors treatment,which is important for increasing pregnancy rate and assisted reproductive technique success rate in infertile couples.The large-size,randomly controlled clinical trials are required to further evaluate the role of aromatase inhibitors,and make them as promising conventional and standard therapeutic regimes for male infertility.