Abstract
Background: The placenta is the base for the exchange of nutrients, oxygen and waste products for the fetus.
The placental vessels hold a crucial role in regulation of blood flow, and compromised function may lead to complications like growth retardation and preeclampsia where no specific treatment is available. In-depth understanding of the mechanisms involved in control of placental vascular tone are needed to develop new tissue targets for therapeutic intervention.
Method: From fresh born placentas segments of stem villous arteries were carefully dissected. The artery branches were divided. The surrounding trophoblast was removed from one end and left intact in the other, and the segment was divided to give two ring preparations, with or without trophoblast. The preparations were mounted in wire myographs and responses to vasoactive agents were compared.
Results: pD2values for PGF2α, Tx-analog U46619, 5-HT and endothelin-1 were significantly lower in preparations with intact trophoblast compared to preparations where the trophoblast had been removed. Moreover, maximal force development (Emax) was lower in arteries with intact trophoblast after stimulation with high extracellular [K+], PGF2α or endotheline-1. These differences partly disappeared in the presence of L-NAME.
Conclusion: The perivascular tissue significantly reduces sensitivity and force development of stem villous arteries, partly due to release of NO This represents a new mechanism for control of human stem villous artery tone.
The placental vessels hold a crucial role in regulation of blood flow, and compromised function may lead to complications like growth retardation and preeclampsia where no specific treatment is available. In-depth understanding of the mechanisms involved in control of placental vascular tone are needed to develop new tissue targets for therapeutic intervention.
Method: From fresh born placentas segments of stem villous arteries were carefully dissected. The artery branches were divided. The surrounding trophoblast was removed from one end and left intact in the other, and the segment was divided to give two ring preparations, with or without trophoblast. The preparations were mounted in wire myographs and responses to vasoactive agents were compared.
Results: pD2values for PGF2α, Tx-analog U46619, 5-HT and endothelin-1 were significantly lower in preparations with intact trophoblast compared to preparations where the trophoblast had been removed. Moreover, maximal force development (Emax) was lower in arteries with intact trophoblast after stimulation with high extracellular [K+], PGF2α or endotheline-1. These differences partly disappeared in the presence of L-NAME.
Conclusion: The perivascular tissue significantly reduces sensitivity and force development of stem villous arteries, partly due to release of NO This represents a new mechanism for control of human stem villous artery tone.
| Originalsprog | Dansk |
|---|---|
| Publikationsdato | 11 jun. 2014 |
| Antal sider | 1 |
| Status | Udgivet - 11 jun. 2014 |