Decreased circulating anandamide levels in preeclampsia.

The endocannabinoid system has a key role in female reproduction, including implantation, decidualization and placentation. A growing number of studies indicate that placental and peripheral blood anandamide levels correlate closely with both spontaneous miscarriage and ectopic pregnancy. Anandamide has also been implicated in blood pressure regulation. In this study, we aimed to determine circulating anandamide levels in preeclampsia for the first time in the literature. Forty-three preeclamptic patients and 71 healthy pregnant women were involved in this case-control study. Serum anandamide concentrations were determined by high-performance liquid chromatography-mass spectrometry technique. Serum total soluble fms-like tyrosine kinase-1 (sFlt-1) and biologically active placental growth factor (PlGF) levels were measured by electrochemiluminescence immunoassay. For statistical analyses, nonparametric methods were applied. Serum levels of anandamide were significantly lower in preeclamptic patients than in healthy pregnant women (0.75 (0.44-1.03) ng ml-1 vs. 1.30 (0.76-2.0) ng ml-1, P<0.001). Preeclamptic patients had significantly higher sFlt-1 levels (12 121 (7963-18 316) pg ml-1 vs. 2299 (1393-3179) pg ml-1, P<0.001) and significantly lower PlGF concentrations (71.2 (39.2-86.4) pg ml-1 vs. 256.8 (181.1-421.0) pg ml-1, P<0.001) as compared with healthy pregnant women. Serum anandamide concentrations did not correlate with serum levels of sFlt-1 and PlGF in our healthy pregnant and preeclamptic groups. In conclusion, we demonstrated for the first time in the literature that serum anandamide concentrations are decreased in women with preeclampsia. However, the cause and consequence of this observation remain to be determined.Hypertension Research advance online publication, 26 February 2015; doi:10.1038/hr.2015.20.