Expression of the endocannabinoid system in human first trimester placenta and its role in trophoblast proliferation.

The endocannabinoid, anandamide, which binds to two major receptor proteins, the cannabinoid receptors (CBs) 1 and 2 (CB1 and CB2), has been shown to play a role in first trimester miscarriage possibly through impairment of the developing trophoblast. Although the precise molecular mechanisms underlying this are unknown, plasma anandamide levels are known to be regulated by the progesterone-induced enzyme, fatty acid amide hydrolase (FAAH). Here, we tested the hypothesis that temporal-spatial expression of FAAH, CB1, and CB2 is regulated during early pregnancy and that anandamide detrimentally alters trophoblast proliferation. Transcripts for CB1, CB2, and FAAH were demonstrated in first trimester trophoblast extracts with only the CB1 transcript being significantly regulated. The significant 4.7-fold increase in expression at wk 10 gestation was reduced to 8.9% of the peak value by wk 12. Transcripts for CB2 showed a similar pattern of expression but were not significantly induced. By contrast, FAAH transcript levels appeared to increase toward the end of the first trimester, but again did not reach significance. These observations were supported by immunohistochemical studies that demonstrated a similar pattern of expression at the protein level, with cellular localization for all three proteins concentrated within the syncytiotrophoblast layer. Anandamide also prevented BeWo trophoblast cell proliferation in a dose-dependent manner, with a 50-60% significant inhibition of cell proliferation with concentrations in excess of 3 mum. This effect was mediated through CB2. Together, these data provide insights into how elevated plasma anandamide levels increase the risk of first trimester miscarriage.

Plasma levels of the endocannabinoid anandamide in women--a potential role in pregnancy maintenance and labor?

Although exposure to exocannabinoids (e.g. marijuana) is associated with adverse pregnancy outcome, little is known about the biochemistry, physiology, and consequences of endocannabinoids in human pregnancy. In these studies, we measured the levels of the endocannabinoid anandamide (N-arachidonoylethanolamine, AEA) by HPLC-mass spectrometry in 77 pregnant and 25 nonpregnant women. The mean +/- sem plasma AEA levels in the first, second, and third trimesters were 0.89 +/- 0.14, 0.44 +/- 0.12, and 0.42 +/- 0.11 nm, respectively. The levels in the first trimester were significantly higher than those in either the second or third trimester. During labor, AEA levels were 3.7 times nonlaboring term levels (2.5 +/- 0.22 vs. 0.68 +/- 0.09 nm, P < 0.0001). During the menstrual cycle, levels in the follicular phase were significantly higher than those in the luteal phase (1.68 +/- 0.16 vs. 0.87 +/- 0.09 nm, P < 0.005). Postmenopausal and luteal-phase levels were similar to those in the first trimester. These findings suggest that successful pregnancy implantation and progression requires low levels of AEA. At term, AEA levels dramatically increase during labor and are affected by the duration of labor, suggesting a role for AEA in normal labor.

The one-stop recurrent miscarriage clinic: an evaluation of its effectiveness and outcome.

BACKGROUND: Couples with recurrent miscarriages make several visits to specialized clinics for investigations before treatment is offered. Consequently, 'the interval' between receipt of referral and advice to try for a pregnancy is often lengthy. The objectives of this study were to examine the effect of a 'one-stop' clinic on 'the interval', throughput and the outcome from this clinic. METHODS: The processes for investigation, management and outcomes of 189 couples seen in our Recurrent Miscarriage Clinic (RMC) and their records were reviewed. RESULTS: The one-stop clinic reduced the interval and number of visits by 36% (206.6 to 130.4 days, P < 0.001) and by 60% (2.5 to 1, P < 0.002) respectively. The prevalence and frequency of aetiological factors were similar in those with two and three or more miscarriages (41% versus 45%, P > 0.05). The commonest aetiological factors were thrombophilias (14%) and antiphospholipid syndrome (11%). No cause was identified in 54% of cases. The pregnancy and live birth rates were best in the idiopathic group (75%), those with thrombophilias (64%) and autoimmune antibodies (83%). Older couples had the worse pregnancy rates and outcome. CONCLUSION: A one-stop clinic significantly shortens 'the interval' between referral and initiation of treatment. Investigations should be initiated in women after two consecutive miscarriages.

Endogenous cannabinoids: metabolism and their role in reproduction.

Over the past two decades a number of endogenous compounds that act as ligands for the cannabinoid receptors has been discovered. In analogy with the "endorphins" these compounds have been called "endocannabinoids". Endocannabinoids have been demonstrated in many mammalian tissues including humans and are widely distributed in the CNS, peripheral nerves, uterus, leukocytes, spleen and testicles. The uterus contains the highest levels of anandamide, the first discovered endocannabinoid, suggesting an important role for this substance in reproduction. Several studies have shown anandamide to be involved in the regulation of implantation and reduced activity of the enzyme that degrades anandamide has been associated with early pregnancy loss in humans. The bulk of the literature concerning endocannabinoids is based upon anandamide related studies; therefore, in this review we focus on the metabolism of anandamide and its role in reproduction.