High maternal and fetal plasma urocortin levels in pregnancies complicated by hypertension

Circulating levels of urocortin neuropeptides are impaired in children with overweight

OBJECTIVE

The corticotropin-releasing factor neuropeptides (corticotropin-releasing hormone [CRH] and urocortin [UCN]-1,2,3) and spexin contribute to the regulation of energy balance and inhibit food intake in mammals. However, the status of these neuropeptides in children with overweight has yet to be elucidated. This study investigated the effect of increased body weight on the circulating levels of these neuropeptides.

METHODS

A total of 120 children with a mean age of 12 years were enrolled in the study. Blood samples were collected to assess the circulating levels of neuropeptides and were correlated with various anthropometric, clinical, and metabolic markers.

RESULTS

Plasma levels of UCNs were altered in children with overweight but less so in those with obesity. Furthermore, the expression pattern of UCN1 was opposite to that of UCN2 and UCN3, which suggests a compensatory effect. However, no significant effect of overweight and obesity was observed on CRH and spexin levels. Finally, UCN3 independently associated with circulating zinc-alpha-2-glycoprotein and UCN2 levels, whereas UCN1 was strongly predicted by TNFα levels.

CONCLUSIONS

Significant changes in neuropeptide levels were primarily observed in children with overweight and were attenuated with increased obesity. This suggests the presence of a compensatory mechanism for neuropeptides to curb the progression of obesity.

Urocortins as biomarkers in cardiovascular disease

The urocortins (Ucns) belong to the corticotropin-releasing factor (CRF) family of peptides and have multiple effects within the central nervous and the cardiovascular systems. With growing evidence indicating significant cardioprotective properties and cardiovascular actions of these peptides, the question arises as to whether the plasma profiles of the Ucns are altered in pathologic settings. While reports have shown conflicting results and findings have not been corroborated in multiple independent cohorts, it seems likely that plasma Ucn concentrations are elevated in multiple cardiovascular conditions. The degree of increase and accurate determination of circulating values of the Ucns requires further validation.

Corticotropin-Releasing Factor Family: A Stress Hormone-Receptor System's Emerging Role in Mediating Sex-Specific Signaling

No organ in the body is impervious to the effects of stress, and a coordinated response from all organs is essential to deal with stressors. A dysregulated stress response that fails to bring systems back to homeostasis leads to compromised function and ultimately a diseased state. The components of the corticotropin-releasing factor (CRF) family, an ancient and evolutionarily conserved stress hormone-receptor system, helps both initiate stress responses and bring systems back to homeostasis once the stressors are removed. The mammalian CRF family comprises of four known agonists, CRF and urocortins (UCN1–3), and two known G protein-coupled receptors (GPCRs), CRF₁ and CRF₂. Evolutionarily, precursors of CRF- and urocortin-like peptides and their receptors were involved in osmoregulation/diuretic functions, in addition to nutrient sensing. Both CRF and UCN1 peptide hormones as well as their receptors appeared after a duplication event nearly 400 million years ago. All four agonists and both CRF receptors show sex-specific changes in expression and/or function, and single nucleotide polymorphisms are associated with a plethora of human diseases. CRF receptors harbor N-terminal cleavable peptide sequences, conferring biased ligand properties. CRF receptors have the ability to heteromerize with each other as well as with other GPCRs. Taken together, CRF receptors and their agonists due to their versatile functional adaptability mediate nuanced responses and are uniquely positioned to orchestrate sex-specific signaling and function in several tissues.

Urocortin 1 expression and secretion by human umbilical vein endothelial cells: In vitro effects of interleukin 8, interferon γ, lipopolysaccharide, endothelin 1, prostaglandin F-2α, estradiol, progesterone and dexamethasone

Urocortin 1 (Ucn1) is a 40-amino-acid peptide that has vasodilatory activity and displays immunomodulatory and antioxidant properties. Maternal and cord plasma Ucn1 levels are increased in preeclampsia and preterm labor, but the mechanisms of such increase are poorly known. Thus, we investigated Ucn1 localization in human umbilical cord and assessed some potential stimuli to Ucn1 release by human umbilical vein endothelial cells (HUVEC). Human umbilical cords were obtained at uncomplicated term pregnancy (n=11). Ucn1 localization was assessed by immunohistochemistry and quantified. HUVEC were grown in vitro to confluence, then incubated with serial concentrations of interleukin (IL)-8, interferon (INF)-γ, lipopolysaccharide (LPS), endothelin (ET)-1, prostaglandin (PG)F-2α, estradiol, progesterone and dexamethasone and Ucn1 concentrations were measured in the supernatants. Ucn1 was immunolocalized with similar intensity in umbilical cord arteries, vein and Wharton's jelly. Ucn1 mRNA was detected in all HUVEC cultures and Ucn1 peptide was detectable in culture medium from untreated cells at different time points. Incubation with IFN-γ increased Ucn1 secretion in a dose-dependent manner. Treatments with IL-8, LPS, ET-1 and dexamethasone were able to increase three to fourfold Ucn1 release from cultured endothelial cells. In conclusion, umbilical vessels express Ucn1 and may be a contributive source of Ucn1 release into fetal-placental circulation. IL-8, IFN-γ, LPS, ET-1 and dexamethasone promote Ucn1 secretion from cultured HUVEC.

Expression of urocortin and corticotrophin-releasing hormone receptor-2 in patients with intrahepatic cholestasis of pregnancy

INTRODUCTION

Intrahepatic cholestasis of pregnancy (ICP) is associated with an increased risk of adverse pregnancy outcomes. Fetal distress in ICP is an acute process, and the abnormal expression of placental local vasodilatory factors play an essential role. Urocortin (UCN) exhibits a powerful concentration-dependent vasodilatation effect in the utero-placental-fetal unit. Our study aimed to investigate placental and serum UCN expression in ICP patients.

METHODS

Blood and placenta samples were obtained from the ICP patients and controls. UCN and corticotrophin-releasing hormone receptor-2 (CRH-R2) expression were detected by ELISA, immunohistochemistry, Western Blotting and real-time PCR.

RESULTS

Placental UCN expression of ICP was lower compare to the controls (0.27 ± 0.11 vs. 0.85 ± 0.21) (P < 0.05). Placental CRH-R2 (0.97 ± 0.09 vs. 0.86 ± 0.09) showed no difference between the ICP and controls (P > 0.05). Placental UCN mRNA (1.45 ± 0.31 vs. 0.72 ± 0.29) and CRH-R2 mRNA expression (1.11 ± 0.10 vs. 0.84 ± 0.24) were higher compared to the controls (all P < 0.05). Maternal serum UCN levels demonstrated no difference from 34 (79.47 ± 11.35 pg/ml) to 37 (84.24 ± 13.62 pg/ml) weeks of gestation in controls (P > 0.05). Maternal serum UCN levels of ICP were decreased from 34 (68.53 ± 16.95 pg/ml) to 37 (47.91 ± 15.65 pg/ml) weeks of gestation (P < 0.05) and were lower than controls at 35 (64.19 ± 22.50 pg/ml), 36 (50.06 ± 13.98 pg/ml) and 37 weeks of gestation (all P < 0.05).

DISCUSSION

The down-regulated UCN expression in the placenta and maternal serum during ICP may impair the blood flow regulation of the utero-placental-fetal unit and contribute to fetal distress. Maternal serum UCN levels might represent a potential clinical predictor of adverse fetal outcomes and optimize the clinical management.

Neuroendocrinology of pregnancy and parturition

During pregnancy, the maternal brain drives a series of adaptive mechanisms that are fundamental for allowing fetal growth and development, protecting both mother and fetus from adverse programming and timing of parturition. This neuroendocrine concept is even more complex as fetal brain and placenta also participate as regulators of maternal-placental-fetal physiology. The placenta is now seen as a neuroendocrine organ, acting as a source of several neuroactive factors that may exert their biologic effects either locally or by entering maternal and fetal circulation, thus acting in an autocrine, paracrine, and endocrine manner. A variety of hypothalamic neurohormones (GnRH, GHRH, somatostatin, CRH, oxytocin) are expressed in the placenta. When stress occurs during pregnancy, the maternal, fetal, and placental hypothalamic-pituitary-adrenal (HPA) axes are activated to stimulate a series of responses contributing to maintain physiologic conditions while at the same time avoiding the adverse effects of stress on the mother and offspring. However, when stress is excessive, a number of obstetric complications may occur, such as preterm birth, pre-eclampsia and intrauterine growth restriction, related to an impairment of the placental adaptive response.

Dihydrotestosterone alters urocortin levels in human umbilical vein endothelial cells

Urocortin (UCN1) is a member of corticotrophin-releasing factor (CRF) family, which has been proven to participate in inflammation. Previous work showed that dihydrotestosterone (DHT) could promote the inflammatory process. Little is known about the effect of DHT on UCN1 expression. The aim of our study is to investigate the effects and underlying mechanisms of DHT on endothelial UCN1 expression in the absence and presence of induced inflammation. Therefore, we tested the alterations of endothelial UCN1 expression treated with DHT in the presence or absence of lipopolysaccharide (LPS). Our data showed that DHT alone decreased UCN1 levels, which were attenuated in the presence of the androgen receptor (AR) antagonist flutamide. Conversely, in the presence of LPS, DHT augmented the LPS-induced increase in UCN1 expression, which was, interestingly, not affected by flutamide. When cells were treated with DHT alone, AR was upregulated and translocated into the nuclei, which might repress UCN1 expression via a potential androgen-responsive element found in human CRF family promoter. In the presence of LPS, DHT did not influence AR expression and location while it increased toll-like receptor 4 expression and activation, which was not altered by flutamide. DHT enhanced LPS-induced p38MAPK, ERK1/2, and nuclear factor κB pathway activation, which may contribute to the elevated expression of UCN1. These data suggest that DHT differentially influences UCN1 levels under normal and inflammatory conditions in human umbilical vein endothelial cells, which involves AR-dependent and -independent mechanisms respectively.

The obstetric syndromes: clinical relevance of placental hormones

Preterm delivery, preeclampsia and intrauterine growth restriction are the major diseases of pregnancy. A key role in their pathogenesis is played by the placenta, which is the source of hormones and other important regulatory molecules providing the metabolic and endocrine homeostasis of the fetal-placental unit. Since obstetric syndromes are characterized by important maternal and neonatal morbidity and mortality worldwide, numerous efforts have been made over the years to prevent and treat them. Due to their complex pathogenesis, however, the therapy is poor and not very effective. Therefore, great emphasis is currently given to the prevention of these diseases through the identification of biochemical and biophysical markers, among which placental factors play a crucial role. The increasing knowledge of the role of placental molecules can indeed lead to the development of new therapeutic and diagnostic tools.

Neuroendocrine aspects of placenta and pregnancy

Placenta plays a central role in the regulation of physiological mechanisms of pregnancy, and in particular is the organ of communication between mother and fetus. This action is also related to its ability to produce hormones, growth factors and cytokines during the progression of pregnancy, and in response to stimuli such as stress and inflammation/infection. In the last years the understanding of the physiological and pathological functions of human placenta revealed the hypersecretion of hormones in presence of gestational diseases and raised the question whether this mechanism is cause of disorders of pregnancy, or part of an adaptive response of placenta to resolve adverse conditions. However, there are evidences indicating that changes of placental hormone secretion may have clinical usefulness, since they are measurable in biological fluids, and may be used as predictive markers or prognostic tools. Of particular interest is the role of corticotropin releasing hormone, urocortins and activins in the maintaining physiological pregnancy and in the pathogenesis of diseases (preterm birth and preeclampsia).

Neuroendocrine mechanisms in pregnancy and parturition

The complex mechanisms controlling human parturition involves mother, fetus, and placenta, and stress is a key element activating a series of physiological adaptive responses. Preterm birth is a clinical syndrome that shares several characteristics with term birth. A major role for the neuroendocrine mechanisms has been proposed, and placenta/membranes are sources for neurohormones and peptides. Oxytocin (OT) is the neurohormone whose major target is uterine contractility and placenta represents a novel source that contributes to the mechanisms of parturition. The CRH/urocortin (Ucn) family is another important neuroendocrine pathway involved in term and preterm birth. The CRH/Ucn family consists of four ligands: CRH, Ucn, Ucn2, and Ucn3. These peptides have a pleyotropic function and are expressed by human placenta and fetal membranes. Uterine contractility, blood vessel tone, and immune function are influenced by CRH/Ucns during pregnancy and undergo major changes at parturition. Among the others, neurohormones, relaxin, parathyroid hormone-related protein, opioids, neurosteroids, and monoamines are expressed and secreted from placental tissues at parturition. Preterm birth is the consequence of a premature and sustained activation of endocrine and immune responses. A preterm birth evidence for a premature activation of OT secretion as well as increased maternal plasma CRH levels suggests a pathogenic role of these neurohormones. A decrease of maternal serum CRH-binding protein is a concurrent event. At midgestation, placental hypersecretion of CRH or Ucn has been proposed as a predictive marker of subsequent preterm delivery. While placenta represents the major source for CRH, fetus abundantly secretes Ucn and adrenal dehydroepiandrosterone in women with preterm birth. The relevant role of neuroendocrine mechanisms in preterm birth is sustained by basic and clinic implications.

Corticotrophin-releasing factor and urocortin inhibit system A activity in term human placental villous explants

Plasma corticotrophin-releasing factor (CRF) and urocortin are elevated in preterm labour and/or fetal growth restriction (FGR). FGR is associated with reduced placental system A amino acid transporter activity and in vitro data suggest altered endocrine status could be responsible. Here we test the hypothesis that CRF and urocortin inhibit placental system A activity. Chronic (48h) exposure of term placental villous explants to these hormones (10(-7)M) significantly reduced system A activity (Na(+)-dependent (14)C-methylaminoisobutyric acid uptake), whereas 1h exposure had no effect. We propose elevated CRF and urocortin contribute to FGR through negative regulation of placental system A activity.

Baby on board: do responses to stress in the maternal brain mediate adverse pregnancy outcome?

Stress and adverse environmental surroundings result in suboptimal conditions in a pregnant mother such that she may experience poor pregnancy outcome including complete pregnancy failure and preterm labor. Furthermore her developing baby is at risk of adverse programming, which confers susceptibility to long term ill health. While some mechanisms at the feto-maternal interface underlying these conditions are understood, the underlying cause for their adverse adaptation is often not clear. Progesterone plays a key role at many levels, including control of neuroendocrine responses to stress, procuring the required immune balance and controlling placental and decidual function, and lack of progesterone can explain many of the unwanted consequences of stress. How stress that is perceived by the mother inhibits progesterone secretion and action is beginning to be investigated. This overview of maternal neuroendocrine responses to stress throughout pregnancy analyses how they interact to compromise progesterone secretion and precipitate undesirable effects in mother and offspring.

Circulating nucleic acids in cancer and pregnancy

Circulating nucleic acids are present in the blood of humans and other vertebrates. During the last 10 years researchers actively studied cell-free nucleic acids present in plasma or serum with great expectations of their use as potential biomarkers for cancer and other pathologic conditions. In the present manuscript the main findings related to the principal characteristics of circulating nucleic acids, the hypothesis on their origin and some methodological considerations on sample collection and extraction as well as on some innovative assay methods have been summarized. Recent reports on the importance of circulating nucleic acids in the intercellular exchange of genetic information between eukaryotic cells have been reviewed.

Prediction of preterm delivery based on maternal plasma urocortin

CONTEXT

Preterm birth still remains a significant management problem, and a large number of markers of the disease have been investigated.

OBJECTIVE

We measured plasma levels of urocortin, a neuropeptide expressed by gestational tissues, in women with threatened preterm labor (TPTL) to evaluate whether the measurement may predict preterm delivery (PTD).

DESIGN

We studied patients as part of an open observational study.

SETTING

The study was conducted at a tertiary referral center for obstetric care.

PATIENTS

Eighty-five women with singleton pregnancies between 28 and 34 completed gestational weeks with TPTL participated in the study.

INTERVENTIONS

Interventions included clinical examination and urocortin measurement.

MAIN OUTCOME MEASURES

Pregnancy outcome and evaluation of sensitivity, specificity, and predictive values of urocortin as diagnostic test for PTD were measured.

RESULTS

Thirty of 85 patients (35.3%) had PTD: 23 of 30 delivered within 7 d from admission (delivery time interval: 2.91 +/- 1.62 d; gestational weeks at delivery: 32.12 +/- 1.7); the remaining delivered later (delivery time interval: 11.71 +/- 4.27 d; gestational weeks at delivery: 33.5 +/- 2.18). Urocortin was significantly higher in women who delivered preterm (median 131.2 pg/ml, interquartile interval 115.1-139.4 pg/ml) than in those who progressed to term delivery [95.4 (69.9-101.3) pg/ml, P < 0.0001] and still higher in those delivering within 7 d from admission [137.7 (124.8-141.2) pg/ml]. Receiver operating characteristic curve analysis revealed that urocortin at the cutoff of 113.9 pg/ml had sensitivity of 80%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 90% as a marker for PTD.

CONCLUSIONS

Maternal plasma urocortin concentration is increased in patients with TPTL who have PTD, and its measurement may be a promising new biochemical marker of PTD.

Plasma urocortin levels in the diagnosis of ovarian endometriosis

OBJECTIVE

Urocortin is a neuropeptide, member of the corticotropin-releasing hormone family, that is produced by the human endometrium. Ovarian endometrioma is a prevalent gynecologic disorder still lacking specific serum markers. In the present study we measured systemic levels of urocortin to assess the diagnostic performance of its determination in distinguishing endometriomas from other benign ovarian cysts.

METHODS

Plasma urocortin was measured by radioimmunoassay in women with ovarian endometrioma (n=40) and in women with benign, nonendometriotic ovarian cysts (n=40). The diagnostic accuracy of urocortin measurement was evaluated by receiver operating characteristic curve and compared with the standard marker, CA 125. To support the local origin of the peptide, we also evaluated its localization in endometriomas by immunohistochemistry and its concentrations in cyst fluid and peritoneal fluid of 12 women with endometrioma.

RESULTS

Plasma urocortin levels were twice as high in women with endometrioma (median 49 pg/mL, interquartile range 41-63 pg/mL) than in the control group (19 [15-23] pg/mL, P<.001) and significantly higher in the cystic content of endometriomas than in the peritoneal fluid and plasma (P<.05). The peptide was immunolocalized in endometrioma glands and stromal capillary vessels. Elevated plasma urocortin levels detected 88% of the cases of endometrioma with 90% specificity, whereas CA 125 detected only 65% of the cases with the same specificity.

CONCLUSION

Plasma urocortin is increased in women with endometriomas, and its measurement may be useful for the differential diagnosis of endometrioma compared with other benign ovarian cysts.

LEVEL OF EVIDENCE

II.

Placental neurokinin B mRNA expression increases at preterm labor

INTRODUCTION

Neurokinin B (NKB) is a neuropeptide belonging to the family of tachykinins-related peptides that elicits contractility of human myometrial strips in vitro. The present study evaluates whether placental mRNA and peptide expression of NKB change in women at preterm labor.

METHODS

A group of 26 women with singleton pregnancies were enrolled in the study. Placental tissue specimens were collected from pregnant women delivering after elective cesarean section, after labor at term, or after preterm labor. Changes in placental NKB mRNA and protein expression were evaluated by real-time quantitative RT-PCR analysis and by immunofluorescence respectively.

RESULTS

Placental mRNA expression of NKB was significantly higher after term and preterm labor (P<0.001) than cesarean section, and highest after preterm labor. Immunofluorescent staining in placentas from preterm or term labor was more intense than after cesarean section (P<0.001). In particular, NKB protein expression was higher in placentas collected after preterm labor than those collected after term labor.

DISCUSSION

Neurokinin B mRNA and protein are highly expressed in placenta at term and preterm labor; thus, the involvement of this neuropeptide in the events cascade leading to parturition may be suggested.