Adrenomedullin is an autocrine regulator of endothelial growth in human endometrium

Human endometrium is a mucosa served by a microvascular blood supply that i nvolves benign angiogenesis under the control of ovarian steroids throughou t reproductive life. Adrenomedullin is a multifunctional 52-amino acid pept ide involved in numerous physiological and pathological processes, includin g angiogenesis, growth regulation, differentiation, vasodilation and smooth muscle relaxation. We have previously shown that adrenomedullin is present in the human uterus. To investigate further the role of adrenomedullin in human endometrial angiogenesis, a method for the isolation and culture of n on-pregnant endometrial endothelium was developed. Enzymatic dispersion and 'Percoll' gradient centrifugation, followed by positive selection using Ul ex europaeus agglutinin-coated immunomagnetic beads, yielded pure isolates of endothelium. The cells formed a typical 'cobblestone' monolayer within 5 -7 days and expressed the classic endothelial markers, CD31 and von Willebr and factor. The presence of adrenomedullin immunoreactivity in endometrial endothelial cells was shown by immunohistochemistry both in vitro and in vi vo. Adrenomedullin promotes growth of endothelial cells as measured by [met hyl-H-3] thymidine uptake. Adrenomedullin also induced cyclic AMP in endome trial endothelial cells. These results demonstrate, for the first time, tha t adrenomedullin is an autocrine growth factor for human endometrial endoth elial cells and is thus involved in endometrial angiogenesis.