The Lipiodol Uterine Bathing Effect to Improve Fertility May Include Uterine Natural Killer Cell Up-regulation in the Endometrium

BACKGROUND: Lipiodol has a dramatic short term fertility enhancing effect for women with endometriosis. Microarray studies have shown transcriptomic regulation of molecular markers of endometrial inflammation, most notably a consistent down-regulation of endometrial osteopontin. We further explored the endometrial bathing effect of lipiodol on leukocyte expression in endometrium. METHODS: A cohort of four women, nested within a randomised trial of twelve women assessing the lipiodol uterine bathing effect, was studied as an ‘own control’ group, with their mid-luteal endometrium assessed before and after endometrial lipiodol exposure. Pipelle endometrial sampling allowed endometrial assessment by immunochemistry. Endometrial tissue samples were assessed by immunochemistry for total CD45+ leukocytes, CD68+ macrophages, CD3+ T-cells and CD56+ uterine natural killer cells. RESULTS: There was a statistically significant increase in the mean density of uterine natural killer cells in the endometrium of women post-lipiodol. No other significant differences were found in the mean densities of all leukocytes, macrophages or T cells in the endometrium of women post-lipiodol. CONCLUSIONS: These preliminary data further support the concept of a uterine bathing effect of lipiodol. Whether the increase in the mean density of uterine natural killer cells in the endometrium might contribute to an improvement in endometrial receptivity to embryo implantation merits further investigation.