Expression of the vascular endothelial growth factors B and C and their receptors in human endometrium during the menstrual cycle

Background. Endometrial angiogenesis is important for bleeding control and fertility, and is believed to be regulated by angiogenic growth factors under the influence of ovarian steroids. Objective. To document the pattern of expression of the two angiogenic growth factors, vascular endothelial growth factor (VEGF)-B and VEGF-C, and of their receptors, VEGFR-1, VEGFR-2, and VEGFR-3, in order to investigate their possible role in the regulation of angiogenesis in normal cycling human endometrium. Material and methods. Cryosections of endometrial biopsy specimens obtained from 17 healthy women before laparoscopic sterilization were examined by immunohistochemistry. Results. Vascular endothelial growth factor and VEGF-C and their receptors were all expressed in and around endometrial blood vessels, with no obvious menstrual cycle-dependent changes in expression except for VEGFR-2, which showed stronger expression during the early secretary phase. Stromal blood vessel density did not change significantly during the menstrual cycle. Conclusion. The presence and pattern of expression of these angiogenic growth factors and their receptors suggest that they participate in the regulation of normal endometrial angiogenesis.