The effects of fumonisin B¹ in preeclampsia.
Preeclampsia is the leading cause of foetal and maternal mortality and morbidity in developing countries. In South Africa, maize is a dietary staple for most black African populations and is susceptible to contamination by mycotoxins such as fumonisin B1 (FB1).Fumonisin B1 is a ubiquitous secondary metabolite of Fusarium fungi produced predominantly by Fusarium verticillioides. This mycotoxin shares structural similarities with the backbone of sphingoid bases (sphinganine and sphingosine) which are substrates for the biosynthesis of complex sphingolipids. The mechanism of FB1 toxicity therefore is centred on the disruption of this process. The aim of the present study was to elucidate the possible causal link between FB1 and preeclampsia. Following ethical approval, 20 normotensive and 20 preeclamptic patients were recruited into the study. Blood and placental tissue were collected and processed for further analysis. The presence of FB1 was verified using standard immunohistochemical and electrophoretic techniques. The levels of FB1 and sphingolipids were quantified using high performance liquid chromatography (HPLC). Western blotting was conducted to confirm the presence of FB1 in the serum. Placental tissue apoptosis was evaluated using Hoechst staining and other markers. Lipid peroxidation was measured in serum and placental tissue of both groups. Fumonisin B1 was immunolocalised within the endothelial cells and mesenchymal cells of placentas from both groups, while FB1 was present in cytotrophoblastic cells of preeclamptic patients only. In addition, FB1 concentrations were significantly higher in preeclamptic compared to normotensive serum samples. Sphinganine was significantly elevated in preeclamptic serum samples whilst there was no statistical difference in the sphingosine levels between the groups. Chromatin condensation was higher in the preeclamptic patients. Caspase 3 and Fas were present with greater intensity in preeclamptic samples. The levels of lipid peroxidation were significantly higher in both serum and placental tissue of preeclamptic patients. This study has demonstrated not only the presence of FB1 in the serum and placental tissues of pregnant women but also the potential effects of this mycotoxin in the humans.