Michela Torricelli

Biomarkers of Spontaneous Preterm Birth: An Overview of The Literature in the Last Four Decades

Background: Understanding spontaneous preterm birth ([PTB] < 37 weeks) is difficult due to heterogeneities associated with multitudes of risk factors and pathophysiological pathways. Several biomarkers are routinely used clinically for predicting preterm labor; however, these factors are either nonspecific or detected too late. Objective: Systematic review of literature on PTB biomarkers in the last 40 years to map out the existing knowledge and gaps in understanding PTB biomarkers. Search strategies: Five electronic databases were searched for human studies on PTB biomarkers published in any language between 1965 and 2008. Selection criteria: The phenotype of interest for final data extraction was exclusively spontaneous PTB with no rupture of membranes. Data extraction included (a) general characteristics of the study (clinical setting, period, and study design), (b) study/participant characteristics (inclusion and exclusion criteria, race/ethnicity, number of participants, gestational age at sampling, (c) characteristics of the biomarker (type, rationale for its selection, type of biological sample, and assay used, and (d) concentration of biomarkers in cases and controls. Data collection and analysis: The search yielded 7255 citations and data were extracted from 217 articles which met our inclusion and exclusion criteria. Main results: A total of 116 different biomarkers were reported and these were assayed 578 times in the 217 included studies. Over two thirds of the 217 studies were performed on North American or European populations. No reliable biomarkers emerged as a risk predictor of PTB. Conclusions: Identifying similar studies on biomarkers for the prediction of PTB was a very challenging task due heterogeneities in study design, sampling issues (types, timing and processing), assay methods, and analyses. Major areas of concern identified in this review include poor phenotype definition, nonideal study designs and poor rationale for biomarker selection and assays and population stratification issues.

Effects of dexamethasone and dexamethasone plus naltrexone on pituitary response to GnRH and TRH in normal women.

The hypothesis that glucocorticoids have a direct central inhibitory effect on the reproductive axis is sutained by the identification of glucocorticoid receptors on GnRH-secreting neurons and gonadotropic pituitary cells. It has been proposed that glucocorticoids and opioids interact centrally in the regulation of the GnRH-LH axis. The inhibitory effect of glucocorticoids may manifest not only directly through the hormone-receptor link, but also indirectly through an increase in opioid tone. The aim of this study was to evaluate the role of glucocorticoids and glucocorticoids combined with an opioid antagonist, in the regulation of basal and GnRH- and TRH-stimulated secretion of LH, FSH and Prl in 7 women with normal menstrual cycles. Blood samples were obtained every 10 min for an hour. GnRH (50 μg) and TRH (200 μg) were administered and blood sampling was continued every 15 min for 2 h (day 1). At 5 a.m. the next day, naltrexone (50 mg) was given and at 8 a.m. the GnRH-TRH test was repeated (day 2). At 5 a.m. on day 3, the patients took 2 mg oral dexamethasone and the test was repeated. At 5 a.m. on day 4, the patients took naltrexone and dexamethasone and at 8 a.m. the GnRH-TRH test was repeated. Administration of naltrexone did not cause significant changes in basal concentrations of LH and FSH and their response to GnRH. The area under the curve of the LH response to GnRH on day 3 was significantly less than on days 1, 2 and 4. Administration of naltrexone (day 2) did not cause any significant increase in basal and TRH-stimulated levels of Prl with respect to day 1. On day 3, dexamethasone caused a reduced response of Prl to TRH. Pretreatment with naltrexone (day 4) prevented this reduction. These results suggest that suppression of the response of LH to GnRH induced by dexamethasone may be partly mediated by endogenous opioids. Dexamethasone led to a reduction in the response of Prl to TRH, and naltrexone blocked this suppression. Hence the suppression of Prl and LH by dexamethasone must be partly mediated by endogenous opioids, which must therefore inhibit pituitary secretion of Prl.

Changes in Placental CRH, Urocortins, and CRH-Receptor mRNA Expression Associated with Preterm Delivery and Chorioamnionitis

CONTEXT The pathogenesis of preterm delivery (PTD) is not clear, although inflammation/infection play a major role. Corticotropin releasing-hormone (CRH) and Urocortins (Ucns) are involved in the pathophysiology of PTD. OBJECTIVE This study evaluates trophoblast mRNA expression of CRH, Ucn, Ucn2, Ucn3, and their receptors [CRH-type 1 receptor (CRH-R1), CRH-R2] in infective conditions. To determine whether infection or glucocorticoids contribute to change their placental mRNA expression, the effects of lipopolysaccharide or dexamethasone was evaluated. DESIGN Placentas were obtained from spontaneous PTD; premature rupture of membranes (pPROM) and pPROM with chorioamnionitis. SETTING Placental specimens were collected from women receiving perinatal care at our Division of Obstetrics and Gynecology. PATIENTS OR OTHER PARTICIPANTS Pregnant women delivered preterm were enrolled. INTERVENTIONS mRNA expression was evaluated by RT-PCR. MAIN OUTCOME MEASURE Because CRH and Ucns are involved in immunological functions we evaluated their involvement in PTD with or without infection. RESULTS CRH, Ucn2, and CRH-R1 mRNA expression were higher, while Ucn and CRHR-2 were lower in pPROM with chorioamnionitis than in PTD and pPROM. Ucn3 mRNA expression was lower in pPROM with and without chorioamnionitis than in PTD. The addition of lipopolysaccharide in trophoblast explants decreased Ucn, Ucn3, and CRH-R2 and increased CRH, Ucn2, and CRH-R1 mRNA expression in a dose-dependent manner. Dexamethasone increased CRH and decreased Ucn2 mRNA expression in a dose dependent manner. CONCLUSIONS Our findings showed a significant impact of pPROM with chorioamnionitis on placental CRH peptides and receptors, suggesting that placental expression of stress-related pathways is activated in infective process.

Maternal risk factors for preterm birth: a country-based population analysis

OBJECTIVE The aim of this study was to identify maternal risk factors for spontaneous preterm birth (PTB) compared to delivery at term, in order to recognize high risk women and to provide a global overview of the Italian situation. STUDY DESIGN A multicenter, observational and retrospective, cross-sectional study was designed. The study population comprised 7634 women recruited in 9 different University Maternity Hospitals in Italy. The main criteria for inclusion were: women having had vaginal preterm or term spontaneous delivery in each participating centre during the study period. The records related to deliveries occurring between April and December 2008. A multivariable logistic regression was employed to identify independent predictors of spontaneous preterm birth. Odds ratios (ORs) and 95% confidence intervals (95% CI) were reported with two-tailed probability (p) values. Statistical calculations were carried out using SAS version 9.1. A two-tailed p-value of 0.05 was used to define statistical significant results. RESULTS A significant increased risk of PTB was found in women with BMI>25 (OR=1.662; 95% CI=1.033-2.676; p-value=0.0365) and in women employed in heavy work (OR=1.947; 95% CI=1.182-3.207; p-value=0.0089). Moreover there was a significant association between PTB and previous reproductive history. In fact a history of previous abortion (OR=1.954; 95% CI=1.162-3.285; p-value=0.0116) or previous cesarean section (OR=2.904; 95% CI=1.066-7.910; p-value=0.0371) was positively correlated to the increased risk of PTB and an important statistically significant association was calculated between PTB and previous pre-term delivery (OR=3.412; 95% CI=1.342-8.676; p-value=0.0099). All the other covariates examined as potential risk factors for PTB were not found to be statistically significantly related (p-value>0.05). CONCLUSIONS The present study, applied to a substantial sample of Italian population, demonstrates that there are peculiar risk factors for spontaneous PTB in the Italian population examined. It shows an association between preterm delivery and certain maternal factors as: BMI, employment, previous abortions, previous PTBs and previous cesarean section.

Urocortin increases IL-4 and IL-10 secretion and reverses LPS-induced TNF-alpha release from human trophoblast primary cells.

Problem  As urocortin (Ucn) is a placental peptide belonging to the corticotrophin‐releasing hormone (CRH) family that modulates immune function in other biological models, this study evaluated Ucn effects on cytokines secretion from cultured human trophoblast cells.

Hormonal and clinical effects of GnRH agonist alone, or in combination with a combined oral contraceptive or flutamide in women with severe hirsutism

The objective of this prospective randomized study was to evaluate and compare the hormonal and clinical effects of long-acting gonadotropin-releasing hormone (GnRH) agonist and a combination of GnRH agonist with combined oral contraceptive (COC) or flutamide in women with polycystic ovary syndrome (PCOS). Thirty-five hirsute women with PCOS, ranging in age from 19–27 years, were randomly divided into three groups: group A treated with GnRH agonist (n = 12), group B (n = 12) treated with GnRH agonist plus COC and group C (n = 11) treated with GnRH agonist plus flutamide for 6 months. Before, at the end and 6 months after the end of treatment, blood samples were drawn from all women (in early follicular phase in those with menstrual cycles) to measure ovarian and adrenal androgens, gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH), estradiol and estrone plasma levels. The results showed that all three protocols had good therapeutic efficacy. A significant reduction in hirsutism was observed in all patients after 6 months of therapy, the Ferriman–Gallwey scores dropping to 9 ± 3 in group A, 10 ± 4 in group B and 11 ± 5 in group C. Six months after the end of therapy, the hirsutism score continued to be significantly reduced in all groups. After 6 months of therapy, a reduction in plasma levels of LH, FSH, estrone, estradiol, testosterone, free testosterone, androstenedione and dehydroepiandrosterone sulfate (DHEAS) was observed in all groups although this was more pronounced in group B and group C. These therapies may be the basis of future treatments that quickly reduce hirsutism and remove its causes by reducing the secretion of ovarian and adrenal androgens and by blocking androgen receptors.

Understanding Spontaneous Preterm Birth: From Underlying Mechanisms to Predictive and Preventive Interventions

Preterm birth is defined as birth before 37 weeks’ gestational age. With an incidence of 7% to 11%, it is one of the major causes of perinatal mortality and morbidity. Preterm birth is considered a clinical syndrome, which arises from different pathological processes that activate prematurely one or more components of the mechanisms leading to parturition. The premature activation of labor may be caused by multiple pathological conditions; in particular a deregulation of the immune system and an exaggeration of inflammatory processes represent common central mechanisms. The complex pathogenesis, the main risk factors and the different therapeutic options will be described in the present review. Since its incidence is still increasing in the last decades, the goal is to improve the primary and secondary prevention.

ORIGINAL ARTICLE: Urocortin Increases IL-4 and IL-10 Secretion and Reverses LPS-induced TNF-α Release from Human Trophoblast Primary Cells

Problem  As urocortin (Ucn) is a placental peptide belonging to the corticotrophin‐releasing hormone (CRH) family that modulates immune function in other biological models, this study evaluated Ucn effects on cytokines secretion from cultured human trophoblast cells.

Heat-killed Lactobacillus rhamnosus GG Modulates Urocortin and Cytokine Release in Primary Trophoblast Cells

A number of studies are showing that probiotic treatment induces an anti-inflammatory state. Intrauterine infection can lead to preterm delivery by modulating immune function and efforts to prevent this condition are ongoing nowadays. Lactobacillus rhamnosus GG (LGG) is a probiotic known to ameliorate inflammation by increasing local anti-inflammatory mediators in urinary and gastrointestinal tracts. The present study then analyzed the effect of heat-killed LGG over β-hCG, progesterone, interleukins (IL) 4 and 10, tumor necrosis factor-α (TNF-α), corticotropin releasing hormone (CRH) and urocortin (Ucn) release by primary trophoblast cells. Normal human term placentas (n = 6) were collected and purified trophoblast cells were incubated in the presence of LGG, lipopolysaccharide (LPS) or either LGG + LPS during 3 h, after which the target substances were quantified by ELISA and real-time PCR. LGG did not affect β-hCG, progesterone, or CRH secretion. Conversely, LGG increased IL-4 protein and mRNA expression (P < 0.05) while IL-10 and Ucn secretion were increased in a dose dependent manner and the highest dose of LGG increased significantly IL-10 mRNA (P < 0.05). LGG did not alter TNF-α, while LPS exposure increased TNF-α protein (P < 0.001) and mRNA expression (P < 0.01). Conversely, LGG treatment reversed LPS-induced TNF-α release at both protein (P < 0.01) and mRNA levels (P < 0.05) in a dose dependent fashion. In conclusion, LGG stimulates IL-4, IL-10 and Ucn expression and reverses LPS-induced TNF-α release from trophoblast cells, with no change in β-hCG or progesterone release, suggesting that this probiotic may play a role as an immunomodulatory agent in human placenta without altering basic trophoblast functions.

Changes of Placental Kiss-1 mRNA Expression and Maternal/Cord Kisspeptin Levels at Preterm Delivery

Kisspeptin, a placental polypeptide secreted throughout pregnancy, is suggested to play a role at parturition. Here we evaluated whether its placental mRNA expression and maternal/fetal plasma levels change at term and preterm delivery, and its effect on oxytocin secretion from placental explants. Samples were collected from 40 women with singleton pregnancies who underwent elective cesarean section at term (TNL), term vaginal delivery (TD), and preterm vaginal delivery (PTD). Plasma Kisspeptin and oxytocin levels were assessed by ELISA; placental mRNA expression by Real-time quantitative RT-PCR analysis. Placental expression was significantly (P < 0.0001) higher in PTD than TNL and TD and significantly (P < 0.001) higher in TD than TNL. Maternal/fetal plasma concentrations did not differ among the groups, and maternal were significantly higher than fetal levels (P < 0.05). In placental explants increasing doses of kisspeptin did not modify oxytocin secretion. In conclusion, labor is associated with increased placental KiSS-1 expression without changes in maternal/fetal circulation.