Endocrinology: The effect of high-dose medium- and long- term progestogen exposure on endometrial vessels

A total of 19 paraffin-embedded endometrial tissue blocks wereobtained from high-dose progestogen-exposed patients. A labelledstreptavidin—biotin—alkaline phosphatase methodwas used with antibodies against von Willebrand factor (vWF)and CD34. The density of CD34 and vWF positive (CD34⁺ and vWF⁺)vessels in progestogen-exposed endometria (103 ± 9.6/mm²and 106 ± 8.7/mm²) was significantly lower than in endometriafrom women with normal cycles (169 ± 9.3/mm² and 136± 8.0/mm²) (P < 0.05). In women with normal menstrualcycles the concentration of CD34⁺ vessels was significantlyhigher than the number of vWF⁺ vessels (P = 0.0001). By comparison,the concentration of CD34⁺ vessels was similar to the concentrationof vWF⁺ vessels in progestogen-exposed endometria. The ratiosof vascular density as determined by vWF⁺ and CD34⁺ stainingin the control and progestogen groups were 0.81 and 1.05 respectively(P = 0.0001). Dilated venules were seen in the progestogen group.This study has demonstrated firstly that CD34 antibody detectedthe endothelial cells in a higher proportion of small endometrialvessels than vWF, and secondly that high-dose progestogen exposuresignificantly decreased the density of microvessels and increasedthe number of dilated venules in endometrium.