For her research (conducted at the Academic Medical Centre, University of Amsterdam) Van Wijk isolated blood vessels from pieces of tissue taken from pregnant women. She placed the blood vessels in a solution of microparticles isolated from the blood of pregnant women with and without pre-eclampsia. A so-called wire myograph was then used to measure the functioning of the blood vessels.
Vessels in a solution of 'affected' microparticles were found to function less well than vessels with 'healthy' particles. Which microparticles or parts thereof are responsible for the vessel damage is not clear. Exactly how the particles are formed must also be investigated.
Van Wijk's research has also revealed that it is not just the inner lining of the vessel wall which functions inadequately during pre-eclampsia. The smooth muscle cells on the outside of the vessels also function less effectively. These muscle cells are responsible for the contraction of the vessels.
Van Wijk also investigated the effect of oestrogen on blood vessels. The administration of oestrogen to isolated vessels taken from women with pre-eclampsia, improved the functioning of the inner lining of the vessel walls. However, whether the administration of oestrogen can help to control pre-eclampsia is not yet clear.
Worldwide, pre-eclampsia is one of the most important causes of mortality of the mother and/or child during pregnancy. Blood from women with pre-eclampsia contains more microparticles from white blood cells than that of women without pre-eclampsia. These microparticles could originate, for example, from leucocytes which pass through an affected placenta. The microparticles can activate other cells, which in turn release particles, or directly disrupt the functioning of the blood vessels.
For further information please contact Dr Marja J. van Wijk, tel. 31-715-141-765 (home), e-mail: m.j.vanwijk@amc.uva.nl. The doctoral thesis was defended on 28 January 2003. Ms Van Wijk's supervisors were Prof. O.P. Bleker and Prof. J.A.E. Spaan.
The research was partially funded by the Netherlands Organisation for Scientific Research (NWO).