Marinobufagenin : a new diagnosis target for preeclampsia syndrome?

The bufadienolides, belonging to the cardiac glycosides class are present in humans as well as in some plants and animals. But the major source for these compounds is located in the parotid and skin gland secretions of some toad species, notably Bufo Marinus species.
Marinobufagenin (MBG) is an endogenous mammalian vasoconstrictive and cardiotonic compound that inhibits the α1 isoform of Na+,K+-ATPase, resulting in hypertension and natriuresis. Increased plasma MBG has been observed in mammals presenting volume-expansion, especially when it is associated with fluid retention, like in preeclampsia (PE)[1-3]. Indeed, the enhanced production of MBG in preeclamptic patients has been confirmed in several studies, leading us to consider MBG as a biomarker for preeclampsia[4].

The need has arisen for an accuracy and sensitive analytical method of MBG plasma levels in order to further investigate the implications of MBG in PE, and to help to establish a diagnosis for this syndrome. Nowadays, two quantification methods based each on immunoassays and with a limit of detection at 0.01 nmol/L have been published [5, 6]. However, the high cross-reactivity of both antibodies and MBG analogues has incited us to develop a sensitive and more specific analytical MBG dosage method by the use of several liquid chromatography (LC) strategies.
The MBG standard compound is currently not commercially available. It forced us to develop an effective extraction method of MBG from freshly collected or crystallized toad Bufo Marinus venom. Pure MBG has been successfully extracted from the crystallized toad venom. The identity of the compound has been confirmed by different spectral techniques.