Placenta
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Placental tissues are frequently utilized by scientists studying pregnancy and reproduction and in diverse fields including immunology, stem cell research, genetics, cancer research, and tissue engineering, as well as by clinicians in many therapies. Though the utilization of the human placenta in science and medicine has benefitted many people, little is known about public perspectives of this phenomenon. ⋯ It is argued that knowledge of public views gained from empirical investigation may underpin the development of collection protocols and research projects that are more responsive to public will, spur more extensive utilization in science and medicine of this unique organ, and/or aid in the realization of the mobilization of knowledge about the placenta for clinical and educational ends. New avenues for research on public perspectives of the placenta are proposed.
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Placental vascular tone is critically influenced by nitric oxide (NO) derived from endothelial NO synthase (eNOS) activity. Placental vessels from pregnancies complicated with intrauterine growth restriction present altered NOS-dependent vasodilation. Arginase-2 competes with eNOS for l-arginine and counteracts the NOS-dependent relaxation in umbilical vessels from normal pregnancies. ⋯ In IUGR-derived endothelium there was a generalized reduction in the in vitro eNOS activation (Ser(1177)-P-eNOS/eNOS), and therefore a decreased eNOS/arginase activity ratio. Here we provide ex vivo and in vitro evidence for a vascular role of arginase throughout placental vasculature, negatively controlling NOS activity. This effect seems to be crucial in the pathophysiology of endothelial dysfunction present in IUGR feto-placental vessels.