The use of inositol phosphoglycans as a diagnostic tool in pregnancy
Preeclampsia is a common and well-recognised complication of human pregnancy. It remains one of the main causes of maternal and fetal mortality and morbidity worldwide and no single cause has been identified, though there are many known risk factors. It is a multi-system disorder that affects the vascular endothelium and appears to originate from the placenta. No treatment exists, save the delivery of the fetus and placenta. There is no single diagnostic test for preeclampsia and it remains a clinical diagnosis only. A reliable diagnostic or predictive test could lead to new treatments and this would be of great clinical benefit as it would allow both more effective antenatal surveillance of high-risk pregnancies and also facilitate further research into the aetiology and treatment of preeclampsia. Previously published work has indicated a potential link between preeclampsia and IPGs. The nature of Inositol Phosphoglycans (IPGs) and their involvement (actual and theorised) in several pathologies is described. Pilot clinical data is presented to evaluate the utility of an ELISA assay for IPG-P in the screening and diagnosis of preeclampsia. The assay demonstrates a correlation between IPG-P levels in maternal urine and amniotic fluid in normal women but not in preeclampsia. The levels in preeclamptic women suggest a correlation with clinical severity of the disease. A hypothesis is presented suggesting disruption of maternal-fetal equilibrium in the preeclamptic disease state. Total IPG-P bioactivity assays of serum samples show no difference between preeclamptic and normal women, and it may therefore play no role in the condition. Alternatively, there is the possibility that a sub-fraction or an unidentified, abnormal IPG-P form is part of the process. Additionally, the ELISA assay demonstrates increased urinary IPG-P levels in normotensive labouring women. A second hypothesis is presented to suggest potential links between the onset of normal labour and the pathophysiology of preeclampsia. Finally, proposals for further work are discussed.