Cervical anti-inflammatory cytokine concentrations among first-trimester pregnant smokers

Spontaneous preterm birth: Involvement of multiple feto-maternal tissues and organ systems, differing mechanisms, and pathways

Survivors of preterm birth struggle with multitudes of disabilities due to improper in utero programming of various tissues and organ systems contributing to adult-onset diseases at a very early stage of their lives. Therefore, the persistent rates of low birth weight (birth weight < 2,500 grams), as well as rates of neonatal and maternal morbidities and mortalities, need to be addressed. Active research throughout the years has provided us with multiple theories regarding the risk factors, initiators, biomarkers, and clinical manifestations of spontaneous preterm birth. Fetal organs, like the placenta and fetal membranes, and maternal tissues and organs, like the decidua, myometrium, and cervix, have all been shown to uniquely respond to specific exogenous or endogenous risk factors. These uniquely contribute to dynamic changes at the molecular and cellular levels to effect preterm labor pathways leading to delivery. Multiple intervention targets in these different tissues and organs have been successfully tested in preclinical trials to reduce the individual impacts on promoting preterm birth. However, these preclinical trial data have not been effectively translated into developing biomarkers of high-risk individuals for an early diagnosis of the disease. This becomes more evident when examining the current global rate of preterm birth, which remains staggeringly high despite years of research. We postulate that studying each tissue and organ in silos, as how the majority of research has been conducted in the past years, is unlikely to address the network interaction between various systems leading to a synchronized activity during either term or preterm labor and delivery. To address current limitations, this review proposes an integrated approach to studying various tissues and organs involved in the maintenance of normal pregnancy, promotion of normal parturition, and more importantly, contributions towards preterm birth. We also stress the need for biological models that allows for concomitant observation and analysis of interactions, rather than focusing on these tissues and organ in silos.

Smoking for two- effects of tobacco consumption on placenta

Tobacco smoking is an important public health issue recognized by the world health organization as one of the most serious, preventable risk factors for developing a series of pregnancy pathologies. Maternal smoking is positively associated with intrauterine growth restriction (IUGR) and gestational diabetes (GDM), but negatively associated with preeclampsia (PE). In this review, we examine epidemiological, clinical and laboratory studies of smoking effects on immunoregulation during pregnancy, trophoblast function, and placental vasculature development and metabolism. We aim to identify effects of tobacco smoke components on specific placental compartments or cells, which may contribute to the understanding of the influences of maternal smoking on placenta function in normal and pathological pregnancies. Data corroborates that in any trimester, smoking is unsafe for pregnancy and that its detrimental effects outweigh questionable benefits. The effects of maternal smoking on the maternal immune regulation throughout pregnancy and the impact of different tobacco products on fetal growth have not yet been fully understood. Smoking cessation rather than treatment with replacement therapies is recommended for future mothers because also single components of tobacco and its smoke may have detrimental effects on placental function.

Association of bacterial vaginosis with periodontitis in a cross-sectional American nationwide survey

To explore the association between bacterial vaginosis (BV) and periodontitis (PD) and to determine whether PD and BV might be linked with systemic serum alterations. We used the National Health and Nutrition Examination Survey 2001-2004, with women aged 18-49 years old and diagnosed with or without BV according to Nugent's method. PD was defined according to the 2012 case definition. We compared serum counts according to the presence of PD and the presence of BV. Multivariable regression was used to explore and identify relevant variables towards the presence of BV. 961 women fulfilled the inclusion criteria. In women with BV, PD was associated with higher inflammation, characterized by increased white blood cells (p = 0.006) and lymphocyte (p = 0.009) counts. Predictive models presented a statistically significant association between PD and BV [Odds Ratio (OD) = 1.69, 95% Confidence Interval (CI): 1.09-2.61 for periodontitis; OD = 2.37, 95% CI: 1.30-4.29 for severe PD]. Fully adjusted models for age, smoking, body mass index, diabetes mellitus and number of systemic conditions reinforced this association [OD = 1.71, 95% CI: 1.06-2.76 for PD; OD = 2.21, 95% CI: 1.15-4.25 for severe PD]. An association between BV and PD is conceivable. PD was associated with higher systemic markers of inflammation in women with BV. Our data is novel and could serve as a foundation to guide future studies in the confirmation of this association and the underlying mechanisms.

Associations between metal concentrations in whole blood and placenta previa and placenta accreta: the Japan Environment and Children's Study (JECS)

Background

Placenta previa and placenta accreta associate with high morbidity and mortality for both mothers and fetus. Metal exposure may have relationships with placenta previa and placenta accreta. This study analyzed the associations between maternal metal (cadmium [Cd], lead [Pb], mercury [Hg], selenium [Se], and manganese [Mn]) concentrations and placenta previa and placenta accreta.

Methods

We recruited 17,414 women with singleton pregnancies. Data from a self-administered questionnaire regarding the first trimester and medical records after delivery were analyzed. Maternal blood samples were collected to measure metal concentrations. The subjects were classified into four quartiles (Q1, Q2, Q3, and Q4) according to metal concentrations.

Results

The odds ratio for placenta previa was significantly higher among subjects with Q4 Cd than those with Q1 Cd. The odds ratio for placenta previa was significantly higher for subjects with Q2 Pb than those with Q1 Pb.

Conclusion

Participants with placenta previa had higher Cd concentrations. However, this study was cross-sectional and lacked important information related to Cd concentration, such as detailed smoking habits and sources of Cd intake. In addition, the subjects in this study comprised ordinary pregnant Japanese women, and it was impossible to observe the relationship between a wide range of Cd exposure and placenta previa. Therefore, epidemiological and experimental studies are warranted to verify the relationship between Cd exposure and pregnancy abnormalities.

Electronic supplementary material

The online version of this article (10.1186/s12199-019-0795-7) contains supplementary material, which is available to authorized users.

Associations of first trimester co-use of tobacco and Cannabis with prenatal immune response and psychosocial well-being

PURPOSE

This study aims to describe the association of first trimester co-use of tobacco and cannabis with maternal immune response and psychosocial well-being, relative to tobacco use only.

METHODS

A preliminary midpoint analysis included 138 pregnant women with biologically verified tobacco use, 38 of whom (28%) also tested positive for recent cannabis use. Maternal perceived stress (Perceived Stress Scale), depressive symptoms (Edinburgh Postnatal Depression Scale), and serum immune markers (IL-1β, IL-2, IL-6, IL-8, IL-10, TNFα, CRP, MMP8), were collected, although cytokine data were only available for 122 women.

RESULTS

Participant average age was 29.1 years, approximately half had a high school education or less, and half were unemployed. Compared to tobacco only users, co-users were more likely to be non-White, younger and more economically disadvantaged. In the adjusted linear regression models, TNF-α levels were significantly lower among co-users relative to tobacco only users, after adjusting for age, race/ethnicity, body mass index and tobacco use group (tobacco cigarettes, electronic nicotine delivery devices [ENDS] or both). TNF-α was the only immune marker found to be significant in this analysis. Measured stress levels (M = 5.9, SD = 3.3; potential range 0-16) and depression scores (M = 7.8, SD = 5.8; potential range 0-30) were low across all participants and did not differ as a function of co-use.

CONCLUSION

Preliminary results suggest women co-using during the first trimester exhibit decreased pro-inflammatory immune responsivity on one out of eight markers. Further research is needed to determine the impact of this immune modulation on fetal health outcomes and the unique contribution of cannabis.

Optimising the collection of female genital tract fluid for cytokine analysis in pregnant women

Introduction

To better understand the immunology of pregnancy, study of female genital tract fluid (FGF) is desirable. However the optimum method of collection of FGF in pregnant women for immunological methods, specifically cytokine measurement, is unknown.

Methods

A prospective study of HIV-uninfected pregnant women comparing two methods of FGF collection: polyvinyl acetal sponge collection of cervical fluid (CF) and menstrual cup collection of cervicovaginal fluid (CVF). Samples were collected at 3 time points across the second and third trimesters: 14–21, 22–25 and 26–31 weeks. Multiplex chemi-luminescent assays were used to measure: IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13 and TNF-α. Optimal methodology for cytokine normalisation (sample weight, volume and total protein) was explored.

Results

All cytokines were measurable in both fluid types. IL-1β, IL-8 and IL-6 were detected at the highest concentrations (ranking order CF > CVF > plasma). CVF collection was simpler, provided the largest volume of sample (median 0.5 g) with the potential for undiluted usage, and allowed for self-insertion. CF cytokine concentrations were intrinsically associated with sample weight and protein concentration however CVF cytokines were independent of these.

Conclusion

Both methods of collection are robust for measurement of FGF cytokines during pregnancy. We recommend CVF collection using a menstrual cup as a viable option in pregnant women for high dimensional biological techniques.

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PVA sponges and MCs are robust methods for measuring FGF cytokines in pregnancy.

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MCs enable collection of large undiluted CVF volumes for high dimensional assays.

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CVF (not CF) cytokine concentrations are largely independent of sample weight or protein.

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Self-insertion and short collection time of MCs is an attractive option to women.

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Cytokine concentrations are higher in sponge samples reflecting the CF immune site.

The Interplay of Host Immunity, Environment and the Risk of Bacterial Vaginosis and Associated Reproductive Health Outcomes

Bacterial vaginosis (BV) is one of the most common causes of vaginal symptoms in US women, but its causal mechanism has not yet been defined. BV is more prevalent in women who are immunosuppressed, and several risk factors for the development of BV are associated with lower quantities of immune mediators in vaginal fluid. In contrast, the poor reproductive health outcomes associated with BV, such as preterm birth and human immunodeficiency virus type 1 acquisition, are associated with increased levels of proinflammatory immune mediators in the genital tract. In this article, we discuss how variations in the host immune profile and environmental effects on host immunity may influence the risk of BV, as well as the risk of complications associated with BV.

The vaginal microbiota over an 8- to 10-year period in a cohort of HIV-infected and HIV-uninfected women

BACKGROUND

We identified predominant vaginal microbiota communities, changes over time, and how this varied by HIV status and other factors in a cohort of 64 women.

METHODS

Bacterial DNA was extracted from reposited cervicovaginal lavage samples collected annually over an 8-10 year period from Chicago Women's Interagency HIV Study participants: 22 HIV-negative, 22 HIV-positive with stable infection, 20 HIV-positive with progressive infection. The vaginal microbiota was defined by pyrosequencing of the V1/V2 region of the 16S rRNA gene. Scheduled visits included Bacterial vaginsosis (BV) screening; clinically detected cases were referred for treatment. Hierarchical clustering identified bacterial community state types (CST). Multinomial mixed effects modeling determined trends over time in CST, by HIV status and other factors.

RESULTS

The median follow-up time was 8.1 years (range 5.5-15.3). Six CSTs were identified. The mean relative abundance (RA) of Lactobacillus spp. by CST (with median number of bacterial taxa) was: CST-1-25.7% (10), CST-2-27.1% (11), CST-3-34.6% (9), CST-4-46.8% (9), CST-5-57.9% (4), CST-6-69.4% (2). The two CSTs representing the highest RA of Lactobacillus and lowest diversity increased with each additional year of follow-up (CST-5, adjusted odds ratio (aOR) = 1.62 [95% CI: 1.34-1.94]; CST-6, aOR = 1.57 [95 CI: 1.31-1.89]), while the two CSTs representing lowest RA of Lactobacillus and higher diversity decreased with each additional year (CST-1, aOR = 0.89 [95% CI: 0.80-1.00]; CST-2, aOR = 0.86 [95% CI: 0.75-0.99]). There was no association between HIV status and CST at baseline or over time. CSTs representing lower RA of Lactobacillus were associated with current cigarette smoking.

CONCLUSIONS

The vaginal microbial community significantly improved over time in this cohort of women with HIV and at high risk for HIV who had regular detection and treatment referral for BV.

Pregnancy-induced changes in immune protection of the genital tract: defining normal

OBJECTIVE

Both the state of pregnancy as well as disruption of vaginal flora and immune mediators may increase the risk of human immunodeficiency virus-1 acquisition. The objective of this study was to define immune changes in lower genital and systemic immunity associated with normal pregnancy.

STUDY DESIGN

This prospective cohort enrolled low-risk pregnant and nonpregnant women ages 18-35 years. Pregnant women at <14 weeks and nonpregnant women in follicular phase of the menstrual cycle were included. Cervical and vaginal fluid was collected. Concentrations of immune mediators were measured using enzyme-linked immunosorbent assay-based methods or multiplex immunoassay. Samples were inoculated onto various culture media allowing for growth of Lactobacillus species, Gardnerella vaginalis, Escherichia coli, Enterococcus species, anaerobic gram-negative rods, Candida, Staphylococcus aureus, Ureaplasma species, and Mycoplasma hominis. Concentrations of immune mediators and vaginal colonization frequencies were compared between the pregnant and nonpregnant groups.

RESULTS

Genital tract concentration of interleukin-1β was higher during pregnancy compared to nonpregnant participants. Serum C-reactive protein concentrations were higher in all trimesters of pregnancy. Concentrations of secretory leukocyte protease inhibitor did not differ between groups. Lactobacillus was more commonly isolated from vaginal cultures of nonpregnant participants (100% vs 70.2%, P = .02). Identification of Candida, G vaginalis, M hominis, and S aureus was common and not different between groups. Ureaplasma species was isolated from >60% pregnant participants.

CONCLUSION

The proinflammatory cytokine, interleukin-1β, as well as the systemic marker of inflammation, C-reactive protein, are increased during pregnancy. The impact of these proinflammatory changes during pregnancy deserves further study.

The polymorphisms of IL-4, IL-4R and IL-13 genes and bladder cancer risk in a Chinese population: a case-control study

Accumulating evidence suggests that inflammatory process may play a role in bladder carcinogenesis. However, the exact mechanisms of how the inflammatory factors associate with bladder cancer risk are still unknown. In this study, we explored whether polymorphisms (i.e. IL-4 C-590T, IL-4R Ile50Val, IL-4R Ser478Pro, IL-4R Gln551Arg, IL-13 C-1055T and IL-13 Arg130Gln) of IL-4, IL-4R and IL-13 genes predicted Chinese bladder cancer risk in 817 bladder cancer and 1,141 controls. Genotyping was performed by using the TaqMan method. We did not find any overall association between these single nucleotide polymorphisms (SNPs) and bladder cancer susceptibility in a Chinese population. However, in the classification and regression tree (CART) analysis, we found that carriers of IL-13 C-1055T variant genotype in smokers had a 2.57-fold increased bladder cancer risk with a 55% patient rate (OR = 2.57; 95% CI = 1.93-3.43), comparing with non-smokers. Similar result was also observed in combination of IL-13 C-1055T and IL-13 Arg130Gln in smokers. By multifactor dimensionality reduction (MDR) analysis, the best interaction model was the two-factor model that smokers with the IL-13 C-1055T genotypes were the subgroup to predict bladder cancer risk. The results suggested that the genetic variants in IL-4, IL-4R and IL-13 genes might modulate the bladder cancer risk in a Chinese population.

Subtle perturbations of genital microflora alter mucosal immunity among low-risk pregnant women

OBJECTIVE

Alteration in the vaginal flora has been associated with adverse pregnancy outcomes. The objective of this study was to examine the impact of changes in individual microflora on genital immunity among low-risk pregnant women in early pregnancy.

DESIGN

Cross-sectional study.

SETTING

Large, tertiary care, academic hospital clinic.

POPULATION

Low-risk women were enrolled prior to 14 weeks' gestation.

METHODS

Women were included if they had no medical or previous obstetrical complications, were non-smokers, had no sexually transmitted infections and no intercourse in the last 48 hours. Consenting women underwent speculum examination for collection of vaginal culture and Dacron swabs for cytokine analysis. Semi-quantitative vaginal cultures were performed in a reference laboratory.

MAIN OUTCOME MEASURES

Concentrations of immune mediators were compared in the presence of various organisms. Concentrations were converted to multiples of the median to standardize the values of each mediator. Regression analyses were performed to control for race.

RESULTS

We enrolled 47 women. The frequencies of genital microorganisms were: H(2)O(2) -producing lactobacilli (70%), Ureaplasma urealyticum (66%), Gardnerella vaginalis (45%), anaerobic non-pigmented Gram-negative rods (ANPGNR, 40%), anaerobic pigmented Gram-negative rods (APGNR, 17%). After adjusting for race and body mass index, interleukin-1β, interferon-γ, tumor necrosis factor-α and granulocyte macrophage-colony stimulating factor were increased in the presence of G. vaginalis, ANPGNR, and APGNR. There was no consistent impact on the other markers of immune activation.

CONCLUSION

The presence of individual species impacts genital immunity among low-risk pregnant women. Perturbations in genital immunity could partially explain heterogeneity in adverse pregnancy outcomes.

Mid-trimester cervical inflammatory milieu and sonographic cervical length

OBJECTIVE

The purpose of this study was to explore the relation between the relative balance of pro- and antiinflammatory cytokines in cervical fluid and mid-trimester cervical length.

STUDY DESIGN

In this prospective longitudinal cohort of women with a previous spontaneous preterm birth, mid-trimester cervical length ultrasound scans and cervical fluid levels were obtained serially. Multiple pro- and antiinflammatory cytokines were selected. We summed the multiples of the median for proinflammatory cytokines to generate the proinflammatory and the antiinflammatory scores. The relation between cervical length and pro-/antiinflammatory ratio was assessed by generalized estimating equations.

RESULTS

The pro-/antiinflammatory ratio had a negative linear association with cervical length (beta = -0.09; P < .001). Sixty percent of visits demonstrated greater concentrations of proinflammatory cytokines relative to antiinflammatory cytokines. This relationship did not change between first and last visits.

CONCLUSION

Among women with a previous preterm birth, shorter mid-trimester cervical length is associated with a more proinflammatory balance of cytokines in the cervical inflammatory milieu.

First-trimester cervical inflammatory milieu and subsequent early preterm birth

OBJECTIVE

Our objective was to explore the relation between the pro- and antiinflammatory cervical cytokine balance in early pregnancy and subsequent early preterm birth.

STUDY DESIGN

In this prospective cohort of 218 pregnant women who were enrolled in the first trimester, we assayed cervical concentrations of interleukin-1alpha, -1beta, -6, -4, -10, and -13. Based on these cytokines, we categorized subjects into 1 of 3 strata: high proinflammatory/low antiinflammatory, high antiinflammatory/low proinflammatory, or balanced. The primary outcome of interest was preterm birth at < 34 weeks' gestation.

RESULTS

Women in the high antiinflammatory/low proinflammatory stratum had a subsequent odds ratio for preterm birth < 34 weeks' gestation of 7.7 (95% CI, 4.9-9.1; P = .01), after adjustment for marital status, smoking, bacterial vaginosis, maternal race, and less than high school education.

CONCLUSION

Women with a relatively hyporesponsive cervical inflammatory milieu in early pregnancy are at higher risk of subsequent early spontaneous preterm birth.

Can symptomatology help in the diagnosis of endometriosis? Findings from a national case-control study--Part 1

OBJECTIVE

To determine the value of patient-reported symptoms in diagnosing endometriosis.

DESIGN

A national case-control study.

SETTING

Data from the UK General Practice Research Database for years 1992-2001.

SAMPLE

A total of 5540 women aged 15-55 years, diagnosed with endometriosis, each matched to four controls without endometriosis.

METHODS

Data were analysed to determine whether specific symptoms were highly indicative of endometriosis. Odds ratios for these symptoms were derived by conditional logistic regression analysis.

MAIN OUTCOME MEASURES

Symptoms associated with endometriosis.

RESULTS

The prevalence of diagnosed endometriosis was 1.5%. A greater proportion of women with endometriosis had abdominopelvic pain, dysmenorrhoea or menorrhagia (73%) compared with controls (20%). Compared with controls, women with endometriosis had increased risks of abdominopelvic pain (OR 5.2 [95% CI: 4.7-5.7]), dysmenorrhoea (OR 8.1 [95% CI: 7.2-9.3]), menorrhagia (OR 4.0 [95% CI: 3.5-4.5]), subfertility (OR 8.2 [95% CI: 6.9-9.9]), dyspareunia and/or postcoital bleeding (OR 6.8 [95% CI: 5.7-8.2]), and ovarian cysts (OR 7.3 [95% CI: 5.7-9.4]), and of being diagnosed with irritable bowel syndrome (IBS) (OR 1.6 [95% CI: 1.3-1.8]) or pelvic inflammatory disease (OR 3.0 [95% CI: 2.5-3.6]). Women with endometriosis were also found to consult the doctor more frequently than the controls and were twice as likely to have time off work.

CONCLUSIONS

Specific symptoms and frequent medical consultation are associated with endometriosis and appear useful in the diagnosis. Endometriosis may coexist with or be misdiagnosed as pelvic inflammatory disease or IBS.

Genetic regulation of cervical antiinflammatory cytokine concentrations during pregnancy

OBJECTIVE

The purpose of this study was to evaluate the contribution of maternal genotype to the concentration of interleukin (IL)-4, -10, and -13 in the cervix during the first trimester in the context of bacterial vaginosis and cigarette smoking.

STUDY DESIGN

In this prospective cohort of 116 pregnant women, we examined 72 single nucleotide polymorphisms (SNPs) in 6 genes: IL-4, IL-4 receptor, IL-10, IL-10 receptor alpha, IL-10 receptor beta, and IL-13.

RESULTS

Among black women, an IL-10 receptor beta SNP (rs6517158) demonstrated significant association with IL-10 concentration (P = .04), adjusted for bacterial vaginosis. Among white women, there were 4 SNPs in IL-10 receptor alpha with a highly significant association with IL-10 concentration, adjusted for bacterial vaginosis and smoking.

CONCLUSION

Our data demonstrate a significant relation between cervical concentrations of IL-10 and SNPs in the IL-10 receptor alpha and beta genes. The contribution of genotype to IL-10 concentration is significant, even in the consideration of bacterial vaginosis and smoking.

Evidence of a TH1-shift of local vaginal inflammatory response during bacterial vaginosis

OBJECTIVE

To determine the levels of pro-inflammatory and anti-inflammatory cytokines in the vagina of healthy women and in bacterial vaginosis (BV) patients.

METHODS

Interleukin (IL)-1alpha, 1beta, 5 and 10 were analyzed by ELISA in vaginal wash fluids from 50 non-pregnant patients with BV and 112 healthy women.

RESULTS

Levels of IL-1beta were higher and those of IL-10 lower in BV-patients than in healthy women. There was a tendency towards higher levels of IL-1alpha in BV patients, but these data were not statistically significant.

CONCLUSION

We found evidence for a shift towards a TH1-dominated vaginal cytokine profile in the pathogenesis of BV. Levels of a TH1-cytokine were elevated and those of a TH2-cytokine lowered in BV-patients as compared to healthy controls. This points to a vaginal TH1-response during BV and to the importance of cell-mediated immunity in local vaginal infections.

Racial differences in cervical cytokine concentrations between pregnant women with and without bacterial vaginosis

We have examined the association between cervical cytokine, chemokine and growth factor concentrations with bacterial vaginosis (BV) in pregnant white and black women. A nested case-control analysis was performed to examine 28 cervical cytokine, chemokine and growth factor concentrations in 83 white women (55 with normal flora and 28 with BV) and 81 black women (39 with normal flora and 42 with BV). White women with BV had significantly lower IP10 (P=0.001) and MCP1 (P=0.006) concentrations compared to women with normal flora. Black women with BV had higher IL-1alpha (P<0.001) concentrations than those with normal flora. In women with normal flora, whites had significantly higher levels of IL-1alpha (P=0.047), IL-6 (P=0.010), IL-10 (P=0.016) and PDGF-BB (P=0.010) than blacks. There were no significant concentration differences between white and black women with BV. These results demonstrate significant differences in cytokine and chemokine concentrations between women with and without BV. Ethnic differences in cytokine concentrations were also observed in women with normal flora, indicating that white and black women with normal flora have different cytokine levels, but respond to BV in a similar manner.

Relationships of maternal serum levels of vascular endothelial growth factor and tensile strength properties of the cervix in a rat model of chronic hypoxia

OBJECTIVE

It has been shown that hypoxia leads to alterations in maternal serum levels of vascular endothelial growth factor (VEGF). In this study, we sought to test the hypothesis that chronic hypoxia increases maternal serum levels of VEGF, which in turn cause measurable changes in the viscoelastic properties of the rat uterine cervix.

STUDY DESIGN

Timed-pregnant adult Sprague-Dawley rats were exposed to hypoxia beginning on day 17 of gestation (term = day 22). The following groups of animals were studied: (1) nonpregnant controls (NP, n = 6); (2) normoxia 21% fraction of inspired oxygen (FiO2) (NMX, n = 6); and (3) severe hypoxia 10% FiO2 (HPX; n = 5). A hypoxic chamber was used to assure consistent hypoxic environment. Animals were killed on day 21 of gestation (before labor). Maternal blood was collected immediately following anesthesia and prior to euthanasia. Free serum levels of VEGF were measured by highly specific immunoassays. Tensile strength properties of the cervix were assessed using a stretching regimen designed to mimic labor. Physical parameters measured were: indicators of viscoelasticity (slope; measure of stiffness), plasticity (yield point [YP]; moment the tissue changes its properties from elastic to plastic), strength (break point [BP]; moment of tissue disruption), and displacement at YP (marks the duration of the viscoelastic phase of the stretching) and BP (a measure of the strength of the material). Data were normalized to the dry weight of the cervix.

RESULTS

Hypoxia is associated with increased serum levels of VEGF compared to NP or NMX groups (P = .001). Cervical stiffness was lower in NMX, compared with NP animals (P = .004), and was not significantly influenced by hypoxia (P > .05). Overall there was a significant inverse correlation between slope and maternal serum levels of VEGF (r = -0.85, P < .001). The force required to reach YP was significantly higher for the NP, compared with NMX and HPX groups (P = .004). Hypoxia did not alter the force required to reach the YP (NMX vs HPX, P > .05). Conversely, hypoxia significantly decreased the displacement at YP, indicating a shortening of the elastic phase (NMX vs HPX, P = .021). There was a significant inverse correlation between maternal serum levels of VEGF and the displacement at YP (r = -0.68, P = .002). In vivo, hypoxia decreased the force required to reached the BP (NMX vs HPX, P = .025), but there was no correlation between the levels of maternal serum VEGF and this indicator (r = -0.35, P = .170).

CONCLUSION

Chronic hypoxia induces measurable changes in maternal serum levels of VEGF and tensile properties of the rat cervix, specifically a shortening of the elastic phase. Hypoxia decreases the cervical strength to stretch and predisposes to rupture, but this effect seems to be unrelated to maternal serum levels of VEGF.

Determination of cytokine protein levels in cervical mucus samples from young women by a multiplex immunoassay method and assessment of correlates

Cytokines in cervical mucus are likely to play important roles in controlling pathogens. The cervical mucosal environment is complex, however, with many endogenous and exogenous factors that may affect cytokine levels. We used a multiplex, suspension-array-based immunoassay method to measure 10 proinflammatory (interleukin-1beta [IL-1beta], IL-6, and IL-8) and immunoregulatory (gamma interferon [IFN-gamma], IL-2, IL-4, IL-5, IL-10, IL-12, and IL-13) cytokines in cervical mucus specimens collected via ophthalmic sponge from 72 healthy, nonpregnant women and correlate their levels with biologic and behavioral covariates in a cross-sectional design. Proinflammatory and immunoregulatory cytokines were readily detected, although proinflammatory cytokines were present at markedly higher levels than were immunoregulatory cytokines. Among the covariates examined, the most striking finding was the significant (P < or = 0.05) association between depressed levels of the cytokines IFN-gamma, IL-1beta, IL-6, and IL-10 and cigarette smoking. Also, nonsignificant trends toward lower cytokine levels were found in the settings of incident and persistent human papillomavirus infection. The ready detection of proinflammatory cytokines may be reflective of the female genital tract as an anatomic site that is constantly exposed to immunogenic stimulation. Cigarette smoking appears to downregulate cytokine responses in the cervical mucosa, which may help explain the implicated role of tobacco use as a cofactor for cervical cancer development.