Differential Expression of CB1 Cannabinoid Receptor and Cannabinoid Receptor Interacting Protein 1a in Labor.

Background: The endocannabinoid system is present in multiple organ systems and is involved in smooth muscle regulation, immune function, neuroendocrine modulation, and metabolism of tissues. Limited data are available regarding the presence and role of this system in reproductive tissues. Components of the endocannabinoid system have been identified in myometrial and placental tissues. However, no study has investigated differential expression of the endocannabinoid system in labor. Objectives: The purpose of this study was to identify and quantify two components of the endocannabinoid system, the CB1 cannabinoid receptor and cannabinoid receptor interacting protein 1a (CRIP1a) in uterine and placental tissues, and to determine if there is differential expression in tissues exposed to labor. We hypothesized that CB1 cannabinoid receptor concentration would be altered in uterine and placental tissue exposed to labor compared with tissues not exposed to labor. Study Design: Uterine and placental tissue samples were collected in nine laboring and 11 nonlaboring women undergoing cesarean delivery. CB1 cannabinoid receptor and CRIP1a presence and quantification were evaluated using western blot, immunohistochemistry, and real-time quantitative polymerase chain reaction. Statistical comparisons of laboring and nonlaboring subjects were made for uterine and placental tissue using a Mann-Whitney test. Results: Immunohistochemistry demonstrated positive staining for CB1 cannabinoid receptors and CRIP1a in uterine tissue. The protein abundance of CB1 cannabinoid receptor in uterine tissue was significantly lower in tissues exposed to labor (p=0.01). The protein abundance of CRIP1a was lower in uterine tissue exposed to labor but did not reach statistical significance (p=0.06). mRNA expression of CB1 cannabinoid receptor (p=0.20) and CRIP1a (p=0.63) did not differ in labored compared with nonlabored uterine tissues. Conclusions: Our findings of diminished protein density of CB1 cannabinoid receptor in uterine tissue exposed to labor support the hypothesis that the endocannabinoid system plays a role in parturition. Our data add to the growing body of evidence indicating the endocannabinoid system is of importance for successful reproduction and support the need for additional research investigating this complex system as it pertains to labor. ClinicalTrials.gov ID: NCT03752021.

Endocannabinoid System in Pregnancy Maintenance and Labor: A Mini-Review.

The endocannabinoid system (ECS) is a cell-signaling system present in multiple organ systems and is an integral part of sustaining the microenvironment necessary for early pregnancy success and maintenance. It plays a significant role in embryo development, transport and implantation as well as placentation. The current theory behind the initiation of term labor is that it is a complex, multifactorial process involving sex steroid hormones, prostaglandin production and interplay at the maternal-fetal interface resulting in increased expression of receptors and gap junctions that promote uterine activation. There is increasing evidence that, in addition to early pregnancy events, the ECS plays a regulatory role in pregnancy maintenance and the timing of labor. This review presents an overview of the ECS in pregnancy that focuses on late gestation and parturition.

Novel Approach to Reduction of an Incarcerated Uterus.

BACKGROUND: Incarceration of the pregnant uterus is a rare condition and can lead to bladder obstruction, renal failure, or uterine rupture. We present a novel, noninvasive technique to reduce an incarcerated uterus. METHOD: With conscious sedation, the patient was placed in all-fours position. The physician's hands were placed on the patient's abdomen and pressure applied until the uterine fundus was palpated. Gentle, steady fundal pressure on both sides was directed toward the maternal chest (bilateral mediocephalad pressure) elevating the uterus out of the pelvis. This approach successfully reduced the gravid incarcerated uterus and was well tolerated by the patient and fetus. EXPERIENCE: The author's experience with this method is limited to this case. Prior experience with reduction of the incarcerated uterus has been with methods previously described in the literature. CONCLUSION: In conjunction with conscious sedation and all-fours positioning, transabdominal manipulation of the uterine fundus with bilateral mediocephalad pressure may facilitate reduction of an incarcerated uterus. This method may obviate the need for more invasive procedures.