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.
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The main vasodilator in the placenta is nitric oxide (NO), which is synthesized by endothelial NO synthase (eNOS). Arginase-2 competes with eNOS for l-arginine, and its activity has been related with vascular dysfunction. Recently, we showed that hypoxia induces arginase-2, and decreases eNOS activity in human umbilical vein endothelial cells (HUVEC). ⋯ In HUAEC exposed to hypoxia there were no changes in eNOS and arginase-2 levels, however there was a significant increase of p-eNOS. In contrast, HUVEC showed an increase in arginase-2 and a reduction of p-eNOS in response to hypoxia. These results show that arginases have a vascular role in placental vessels counteracting the NOS-dependent relaxation, which is differentially regulated in placental artery and vein endothelial cells.
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Hypoxia relates with altered placental vasodilation, and in isolated endothelial cells, it reduces activity of the endothelial nitric oxide synthase (eNOS) and l-arginine transport. It has been reported that arginase-2 expression, an alternative pathway for l-arginine metabolism, is increased in adult endothelial cells exposed to hypoxia as well as in pre-eclamptic placentae. We studied in human umbilical vein endothelial cells (HUVEC) whether hypoxia-reduced NO synthesis results from increased arginase-mediated l-arginine metabolism and changes in subcellular localization of eNOS and arginase-2. ⋯ Hypoxia increased arginase-2/eNOS colocalization, and eNOS redistribution to the cell periphery. Altogether these data reinforce the thought that eNOS cell location, post-translational modification and substrate availability are important mechanisms regulating eNOS activity. If these mechanisms occur in pregnancy diseases where feto-placental oxygen levels are reduced remains to be clarified.
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Minimally invasive surgical techniques are becoming increasingly common in gynecologic surgery. However, traditional laparoscopy can be challenging. A robotic surgical system gives several advantages over traditional laparoscopy and has been incorporated into reproductive gynecological surgeries. ⋯ Reproductive outcomes appear similar to alternative approaches. Drawbacks of robotic surgery include longer operating room times, the need for specialized training, and increased cost. Larger prospective studies comparing robotic approaches with laparoscopy and conventional open surgery have been initiated and information regarding long-term outcomes after robotic surgery will be important in determining the ultimate utility of these procedures.