Association of TNF-α genetic polymorphisms with recurrent pregnancy loss risk: a systematic review and meta-analysis

Correlation of TGF-β signaling pathway gene polymorphisms with unexplained recurrent spontaneous abortion

BACKGROUND

The association of key genes in the transforming growth factor-β (TGF-β) signaling pathway and their gene polymorphisms with unexplained recurrent spontaneous abortion (URSA) is unclear.

OBJECTIVE

To investigate the association of gene polymorphisms related to the TGF-β signaling pathway in URSA women.

METHODS

The study population consisted of 80 women with URSA and 90 normal control women, of which 10 women with URSA and 10 normal control women underwent high-throughput sequencing to select loci, and the remaining 70 women with URSA and 80 normal control women underwent flight mass spectrometry experiments to verify gene loci polymorphism. A total of 7 polymorphic loci in interleukin-6 (IL-6), TGF-β1, TNF-α, SMAD1, and TNFRSF4 genes were screened by high-throughput sequencing combined with a review of databases. An SNP flight mass spectrometer (Mass ARRAY detection system) was applied to detect the polymorphisms and their frequencies in 70 women with URSA and 80 normal control women at the 7 gene loci.

RESULTS

Among the 7 loci of IL-6, TGF-β1, TNF-α, SMAD1, and TNFRSF4 genes, 2 loci were found to have significantly different allele and genotype frequency distributions between the 70 URSA and 80 normal controls, one was the IL-6 gene -174G/C locus (rs1800795), the risk of disease was 2.636 and 3.231 times higher in individuals carrying the C allele and CC genotype than in those carrying the G allele and GG genotype, respectively; the other was the TGF-β1 gene -509T/C locus (rs1800469), and the risk of disease was 1.959 and 3.609 times higher in individuals carrying the T allele and TT genotype than in those carrying the C allele and CC genotype, respectively. The remaining 5 genetic loci have no statistically significant.

CONCLUSION

IL-6 gene -174G/C locus (rs1800795) genotype CC and allele C may be the causative factor of URSA, TGF-β1 gene -509T/C locus (rs1800469) genotype TT and allele T may be the causative factor of URSA, and polymorphisms of the 2 loci may be associated with URSA.

Understanding the potential immunogenetic role of TNFα-308 polymorphism in the pathogenesis of recurrent miscarriage

Background

Recurrent miscarriage (RM) represents the spontaneous termination of two or more successive pregnancies. TNFα is a proinflammatory cytokine that is often considered harmful for embryonic development when expressed beyond normal levels.

Aim

The study was conducted to assess the association between TNFα-308 polymorphism and RM pathogenesis.

Methods

Samples of blood were obtained from patients and controls through venipuncture. The levels of TNFα in serum were measured by ELISA. TNFα gene promoter-associated single-nucleotide polymorphism was investigated with polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) techniques with precise primers and the restriction endonuclease, NcoI.

Results

Serum TNFα levels in patients were considerably high (p < 0.05) than controls. The genotype and allele frequencies for TNFα gene polymorphism differs significantly (p = 0.0089; p = 0.0043 respectively) between patients and controls. The TNFα-308 SNP exhibited a link with higher RM risk in heterozygous (GG vs. GA; OR: 3.086, 95% CI: 1.475-6.480; p: 0.0027), dominant (GG vs. GA + AA; OR: 2.919, 95% CI: 1.410-6.056, p: 0.0038), and allelic/codominant (G vs. A; OR: 2.449, 95% CI: 1.313-4.644, p: 0.0064) models. However, this SNP showed an insignificant association with higher and lower RM risk in homozygous (GG vs. AA; OR: 1.915, 95% CI: 0.3804-10.99, p: 0.6560) and recessive (AA vs. GA + GG; OR: 0.6596, 95% CI: 0.1152-3.297, p: >0.9999) models, respectively. Further, the TNFα-308G/A genotype frequencies were in concord with HWE both in the controls (χ² = 3.235; p = 0.1985) and the patients (χ² = 0.0117; p = 0.9942).

Conclusion

The serum TNFα levels were significantly higher in the patients than the controls. The genotyping analysis also demonstrated that TNFα-308G/A SNP significantly increases the overall risk of RM, suggesting that the SNP modulates the TNFα gene expression and thereby increases serum TNFα levels that adversely affect the pregnancy outcome.

The Update Immune-Regulatory Role of Pro- and Anti-Inflammatory Cytokines in Recurrent Pregnancy Losses

Recurrent pregnancy losses (RPL) is a common reproductive disorder with various underlying etiologies. In recent years, rapid progress has been made in exploring the immunological mechanisms for RPL. A propensity toward Th2 over Th1 and regulatory T (Treg) over Th17 immune responses may be advantageous for reproductive success. In women with RPL and animals prone to abortion, an inordinate expression of cytokines associated with implantation and early embryo development is present in the endometrium or decidua secreted from immune and non-immune cells. Hence, an adverse cytokine milieu at the maternal-fetal interface assaults immunological tolerance, leading to fetal rejection. Similar to T cells, NK cells can be categorized based on the characteristics of cytokines they secrete. Decidual NK (dNK) cells of RPL patients exhibited an increased NK1/NK2 ratio (IFN-γ/IL-4 producing NK cell ratios), leading to pro-inflammatory cytokine milieu and increased NK cell cytotoxicity. Genetic polymorphism may be the underlying etiologies for Th1 and Th17 propensity since it alters cytokine production. In addition, various hormones participate in cytokine regulations, including progesterone and estrogen, controlling cytokine balance in favor of the Th2 type. Consequently, the intricate regulation of cytokines and hormones may prevent the RPL of immune etiologies. Local or systemic administration of cytokines or their antagonists might help maintain adequate cytokine milieu, favoring Th2 over Th1 response or Treg over Th17 immune response in women with RPL. Herein, we provided an updated comprehensive review regarding the immune-regulatory role of pro- and anti-inflammatory cytokines in RPL. Understanding the roles of cytokines involved in RPL might significantly advance the early diagnosis, monitoring, and treatment of RPL.

Understanding recurrent pregnancy loss: recent advances on its etiology, clinical diagnosis, and management

Recurrent pregnancy loss (RPL) has become an important reproductive health issue worldwide. RPL affects about 2%-3% of reproductive-aged women, and makes serious threats to women's physical and mental health. However, the etiology of approximately 50% of RPL cases remains unknown (unexplained RPL), which poses a big challenge for clinical management of these patients. RPL has been widely regarded as a complex disease where its etiology has been attributed to numerous factors. Heretofore, various risk factors for RPL have been identified, such as maternal ages, genetic factors, anatomical structural abnormalities, endocrine dysfunction, prethrombotic state, immunological factors, and infection. More importantly, development and applications of next generation sequencing technology have significantly expanded opportunities to discover chromosomal aberrations and single gene variants responsible for RPL, which provides new insight into its pathogenic mechanisms. Furthermore, based upon patients' diagnostic evaluation and etiologic diagnosis, specific therapeutic recommendations have been established. This review will highlight current understanding and recent advances on RPL, with a special focus on the immunological and genetic etiologies, clinical diagnosis and therapeutic management.

TNF-α/anti-TNF-α drugs and its effect on pregnancy outcomes

Pregnancy is a complex biological process. The establishment and maintenance of foetal-maternal interface are pivotal events. Decidual immune cells and inflammatory cytokines play indispensable roles in the foetal-maternal interface. The disfunction of decidual immune cells leads to adverse pregnancy outcome. Tumour necrosis factor (TNF)-α, a common inflammatory cytokine, has critical roles in different stages of normal pregnancy process. However, the relationship between the disorder of TNF-α and adverse pregnancy outcomes, including preeclampsia (PE), intrauterine growth restriction (IUGR), spontaneous abortion (SA), preterm birth and so on, is still indefinite. In this review, we thoroughly reviewed the effect of TNF-α disorder on pathological conditions. Moreover, we summarized the reports about the adverse pregnancy outcomes (PE, IUGR, SA and preterm birth) of using anti-TNF-α drugs (infliximab, etanercept and adalimumab, certolizumab and golimumab) currently in the clinical studies. Overall, IUGR, SA and preterm birth are the most common adverse pregnancy outcomes of anti-TNF-α drugs. Our review may provide insight for the immunological treatment of pregnancy-related complication, and help practitioners make informed decisions based on the current evidences.

Molecular Evaluation of Chlamydia trachomatis Infection and Its Association with Tumor Necrosis Factor-α Polymorphism in Recurrent Spontaneous Abortions

Background

The rate of infections in the intensive care units (ICUs) is rising, mainly because of the increasing use of invasive procedures. Several bacterial infections and host genetic backgrounds, including TNFα SNP polymorphisms, play important roles in recurrent spontaneous abortions (RSA). So, this study aimed to evaluate C. trachomatis infection and its relation with TNFα -308 and -238 polymorphism for early detection and treatment of RSA.

Methods

The blood samples were taken from 63 Iranian women with a history of RSA and 59 ethnically matched healthy controls with at least two successful pregnancies and no history of abortion. Then, DNA was extracted from all samples and detection of C. trachomatis and TNFα -308 and -238 polymorphism was determined by multiplex amplification-refractory mutation system (ARMS)-PCR. Finally, the statistical analysis to detection C. trachomatis and host genetic roles in RSA were analyzed by Epi Info ^TM software by X² test.

Results

C. trachomatis was detected in 22 and 3% of the RSA and the control group, respectively. Moreover, in comparison with healthy controls, C. trachomatis infection was closely correlated with TNFα -308 genotypes, whereas no significant association was observed between TNFα -238G/A and RSA. In addition, statistical analysis of TNFα -308 genotypes showed that the frequency of genotype AA was higher in patients with C. trachomatis infections than healthy individuals and the difference was statistically significant.

Conclusions

This study demonstrated that molecular analysis of TNF -308 genotypes is important in early detection and treatment of RSA with C. trachomatis infection.

Impact of TNF-α profile in recurrent pregnancy loss pathogenesis: A patient based study from Assam

BACKGROUND

Lacunae exist in understanding the underlying etiology in majority of recurrent pregnancy loss (RPL) cases. Given the significance of regulated immune-modulation in pregnancy, and the central role of pro-inflammatory TNF-α plays in it; this study targeted to appraise the significance of TNF-α profile in RPL pathogenesis in an ethnically distinct population from Assam, India.

METHODS

Term delivery, medically terminated pregnancy (MTP) and RPL cases (based on ASRM criteria) were enrolled with no anatomical and chromosomal abnormalities or pathological infections; and blood and/or placenta/product of conceptus (POC) tissue samples were collected with informed consent. Serum level and tissue level TNF-α expression profile were screened using specific molecular tools, and was correlated with TNF-α -308 G/A genotype; for its association with RPL predisposition.

RESULTS

A significant gestation specific increase in serum TNF-α levels was observed in MTP cases (19.932 ± 4.407 pg/mL) compared to term delivery subjects (p = 0.001), while a comparable levels were observed with RPL cases (22.709 ± 5.833 pg/mL) (p = 0.646). A site specific (POC) increased expression was observed in RPL compared to MTP cases at both at transcript (6.37 ± 3.714 folds) and protein levels. The TNF-α -308 variant genotype was associated with increased predisposition to RPL (OR = 1.721) compared to MTP as well as significantly increased serum TNF-α levels (p = 0.017); especially in subjects with a homozygous TNF-α -308 A/A genotype.

CONCLUSION

Our data emphasizes on the importance of site specific TNF-α expression levels in RPL pathogenesis in the studied population, and underlines its importance in screening, clinical stratification, and therapeutics by molecular targeting using TNF-α inhibitors.

Investigating the role of EGF-CFC gene family in recurrent pregnancy loss through bioinformatics and molecular approaches

Recurrent pregnancy loss (RPL) is the most common reproductive failure, reaching 1-5% of women throughout their lives, and having unknown etiology in 50% of the cases. In humans, EGF-CFC1 (Epidermal Growth Factors & Cripto/FRL-1/Cryptic) gene family is composed by TDGF1 and CFC1, two developmental genes. The aim of this study was to investigate the role of EGF-CFC on RPL. To this, multiple approaches were performed; we conducted an expression analysis of TDGF1 and CFC1 using publicly available data from Gene Omnibus Expression (GEO), systems biology analyses and functional prediction; and a molecular analysis carried out in a case-control study. Our GEO analysis showed a decrease in TDGF1 expression in the endometrium (p=0.049) and CFC1 expression in placenta (p=0.015) of women with RPL. Network analysis, gene ontology and literature pointed to a strong connection between EGF-CFC1 gene family to pathways that play key roles during pregnancy, including TGF-β, c-Src/MAPK/AKT, Notch, TNFα, IFNγ and IL-6. A pathogenicity score developed for this gene family showed that the c.-14+1429T>C (rs3806702) variant in the TDGF1 and the p.Arg47Gln (rs201431919) variant in CFC1 gene would be the ones with the highest deleterious effect for RPL. In the case-control study, which involved 149 women with RPL and 159 controls, no statistical difference was observed in the allele and genotype distributions of the variants studied in the two groups. In this study, we performed extensive bioinformatics analysis for biomarker prioritization followed by experimental validation of proposed selected markers. Although there is no statistical difference in the frequencies of these variants between RPL and controls, the expression analysis results suggest that TDGF1 and CFC1 genes might play a role in RPL. In addition, systems biology analyzes raise the hypothesis that genes in other signaling pathways that may be related to RPL as good candidates for future studies.Abbreviations RPL: recurrent pregnancy loss; EGF-CFC1: Epidermal Growth Factors - Cripto/FRL-1; GEO: Gene Omnibus Expression; KEGG: Kyoto Encyclopedia of Genes and Genomes.

Predictive value of PAPP-A for ectopic pregnancy and analysis of related factors

The present study was designed to analyze the expression of pregnancy-associated plasma protein-A (PAPP-A) in the serum of patients with ectopic pregnancy (EP) and related factors inducing this condition. Seventy-five patients with EP admitted to the Affiliated Hospital of Jining Medical University from January 2018 to February 2019 were selected as the research group, and another 59 healthy pregnant women of the corresponding age, gravidity and gestational week were enrolled in the control group. ELISA was employed to detect the serum expression levels of PAPP-A and inflammatory factors such as interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α). ROC was adopted to evaluate the diagnostic value of serum PAPP-A in patients with EP, and Pearson correlation coefficient was applied to analyze the correlation of PAPP-A with inflammatory factors IL-8 and TNF-α. Serum PAPP-A expression was significantly lower in EP patients than those in the control group. The area under the curve (AUC) of serum PAPP-A in diagnosing EP patients was 0.812, and the PAPP-A value in the control group was significantly higher than that of the research group at 7-8 weeks and ≥9 weeks. With regard to the expression of inflammatory factors, the research group presented markedly higher IL-8 and TNF-α levels than the control group. PAPP-A was negatively related to inflammatory factors IL-8 and TNF-α in the research group. In addition, it was revealed that patients with a history of genital surgery, salpingotomy, pelvic infection, EP or low PAPP-A expression were at high risk of EP. In conclusion, PAPP-A was revealed to be lowly expressed in the serum of EP patients, and to negatively be correlated with inflammatory factors IL-8 and TNF-α, which may serve as a useful marker for the diagnosis and prognosis of EP.

Influence of prominent immunomodulatory cytokines TNF-α308 G>A (rs1800629) and TGFβ1 G>C (rs1800471) sequence variations as an important contributing factor in etiopathogenesis of recurrent miscarriages in Kashmiri women (North India)

AIM

We aimed to evaluate the genetic variation of tumor necrosis factor-α (TNF-α) 308 G>A (rs1800629) and transforming growth factor (TGF) β1G>C (rs1800471) to confer risk in patients with recurrent miscarriage in highly consanguineous population of Kashmir (North India).

METHODS

A total of 200 women who experienced two or more recurrent miscarriages (along with 100 spouses, 60 products of conception, and 240 healthy controls) with two or more full-term pregnancies were recruited from the same geographical region and evaluated by polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

TNF-α 308 G>A variant genotype (AA) was significantly associated with recurrent miscarriage cases (2.5% vs. 0.4% controls, respectively; p < 0.05) and its per copy allele A also presented more in cases (32% vs. 24% in controls; p < 0.05) that showed a risk of 1.5-fold for cases (p < 0.05). The difference of variant genotype GA was observed to be significant among recurrent miscarriage cases and product of conception: 60.5% vs. 83%, respectively (p < 0.05) wherein variant TNF-α GA genotype conferred 3-fold risk (p < 0.05). On the other hand, TGF β1 G>C showed no association with recurrent miscarriage cases in our population.

CONCLUSION

The study found both TNF-α 308 G>A variants are significantly associated with an increased susceptibility for recurrent miscarriages to cause pregnancy losses but on the other hand TGF β1 does not seem to impact the outcome of pregnancy in our population.

Tubal ectopic pregnancy occurrence is associated with high expressions of prokineticin receptors and aberrant secretion of inflammatory cytokines

OBJECTIVE

Tubal ectopic pregnancy (TEP) remains the most common cause of maternal morbidity and mortality in the early months of pregnancy. The aim of this study is to perform the correlation between PROKRs and pro-inflammatory genes and explore the role of novel genes in pathogenesis of TEP.

METHODS

Here, quantitative real time PCR and immunohistochemistry were used to assess the expression of the novel genes in 120 TEP patients and 30 age-matched non-TEP patients. The correlation between PROKRs and pro-inflammatory genes were analyzed by Pearson correlation coefficient. Univariate and multivariate Cox regression analyses were used to assess the risk prediction rate of novel genes. Receiver operating characteristic was used to assess the performance of our model.

RESULTS

PROKRs (PROKR1 and PROKR2) and pro-inflammatory genes (TNF-α, IL-6, and IL-8) expression levels significantly enhanced in TEP patients, and significantly positive correlation with pro-inflammatory genes for PROKRs. A multivariate Cox regression analysis demonstrated that 2 genes (PROKR2 and IL8) had significant diagnostic value, which were associated with the occurrence and development of TEP.

CONCLUSION

Our data further denote that dysregulation of PROKR2 and IL-8 were risk factor and played an important role in the pathogenesis of TEP.

Association of IL-1β, IL-6, TNF-α, and TGFβ1 Gene Polymorphisms with Recurrent Spontaneous Abortion in Polycystic Ovary Syndrome

Recurrent spontaneous abortion (RSA) is a common pregnancy-associated complication of polycystic ovary syndrome (PCOS) which is an endocrine malfunction disease. Patients with PCOS may have several underlying contributing and interrelated factors, which have been reported in women with RSA. The incidence rate between PCOS and RSA remains uncertain. The aim of this study is to determine the possible association of IL-1β-511C/T, IL-6-174G/C, TNF-α-1031T/C, and TGFβ1-509T/C with RSA patients with or without PCOS. A total of 140 RSA patients, 70 of which were PCOS patients, and 140 healthy females with no history of RSA or PCOS were included in this study. PCR amplification, genotyping, and sequence analysis were employed to investigate the presence of the polymorphisms. The genotypic and allelic frequencies were calculated separately for each subject. Out of the four studied polymorphisms, the IL-1β-511C/T genotype in RSA without PCOS patients (12.7%) was significantly different compared with that in control subjects (p = 0.047). For IL-6-174C/G, there was a tendency towards more CC carriers among RSA with PCOS patients (10%) than in controls (3%). The GG genotype in RSA women with PCOS (60%) was significantly different compared with that in control subjects (p = 0.033), and the GC genotype in RSA with PCOS patients (30%) showed a marginal significant difference compared with that in control subjects (p = 0.050). Significant difference was identified in the allelic frequencies in RSA patients with PCOS compared to controls (p = 0.025). IL-6-174G/C and TNF-α-1031T/C polymorphisms are significantly associated with RSA patients in Saudi patients with PCOS, while the IL-1β-511C/T polymorphism is significantly associated with RSA patients without PCOS.

Association between polymorphic markers human leucocyte antigen-G and tumour necrosis factor alpha and susceptibility to recurrent miscarriages among Bulgarian women

OBJECTIVE

To analyze the role of 14 base pair (bp) insertion (ins)/deletion (del) and tumour necrosis factor alpha (TNF-α) G/A polymorphisms as risk factors for spontaneous miscarriage in patients with two or more unsuccessful pregnancies and a group of control women with at least two normal live births.

MATERIALS AND METHODS

To investigate the role of these mutations, 50 patients with two or more idiopathic recurrent miscarriages and 50 normal fertile women were tested for the presence of human leucocyte antigen-G (HLA-G) 14 bp ins/del and TNF-α -308 G/A variants. The frequencies of the studied polymorphisms were compared between the two groups.

RESULTS

Individuals with a history of miscarriages had a significantly higher prevalence of 14 bp insertion alleles compared with control patients (p=0.04). There was also a two times higher relative risk for miscarriage among carriers of this variant. No statistical difference in allele frequencies of the TNF-α -308 G/A polymorphism was established between controls and study patients (p=0.78).

CONCLUSION

The 14 bp ins HLA-G variant could be associated with a higher risk for unsuccessful pregnancy according to the results from the study. There is no association between the studied TNF-α -308 GA polymorphism and rate of spontaneous abortions.

Pregnancy complications recur independently of maternal vascular malperfusion lesions

BACKGROUND

Spontaneous abortions, intrauterine growth restriction, and preeclampsia are thought to be caused by defective placentation and are associated with increased risk of adverse outcomes in subsequent pregnancies. However, it is not known whether the recurrence of adverse outcomes is associated with the recurrence of placental pathology. We hypothesized that recurrent maternal vascular malperfusion (MVM) underlies the recurrence of adverse outcomes.

METHODS

Using data from the National Collaborative Perinatal Project, we assessed the recurrence of pregnancy complications and MVM lesions (N = 3865), associations between a history of spontaneous abortions and MVM lesions or adverse outcomes in subsequent pregnancies (N = 8312), and whether the recurrence of pregnancy complications occurred independently of the presence of MVM lesions.

RESULTS

The odds of an MVM lesion were higher for a woman who had had an MVM lesion in a previous pregnancy (aOR = 1.6; 95% CI 1.3-1.9), although this was marginally non-significant after adjusting for covariates such as gestational age, race and BMI. The odds of preeclampsia, a small-for-gestational-age infant, premature delivery and early pregnancy loss were 2.7-5.0 times higher if there had been that same adverse outcome in a previous pregnancy. A history of spontaneous abortions was associated with higher risk of a small-for-gestational-age baby (aOR = 2.4; 95% CI 1.7-3.4) and prematurity (aOR = 5.1; 95% CI 2.3-11.5 for extremely preterm), but not preeclampsia. The recurrence of adverse outcomes was significant when restricting analyses to women without MVM lesions. Similarly, associations between adverse outcomes and previous spontaneous abortions were significant when statistically controlling for the presence of MVM lesions, or excluding pregnancies with MVM lesions.

CONCLUSIONS

Women with adverse outcomes in one pregnancy are at higher risk of complications in subsequent pregnancies. However, there is significant recurrence of adverse outcomes even in the absence of MVM.

Associations between tumor necrosis factor-α and interleukin-6 polymorphisms and unexplained recurrent spontaneous abortion risk: A meta-analysis

To evaluate the associations between Tumor necrosis factor-α (TNF-α)(-238G>A) and Interleukin-6 (IL-6)(-174G>C) polymorphism and risk of unexplained recurrent spontaneous abortion (URSA).Correlated case-control studies were collected by computer retrieval. A meta-analysis was conducted by Stata 12.0 software to analysis the strength of association between polymorphism of TNF-α -238G>A and IL-6 -174G>C and URSA.Twenty-one articles with twenty-two studies were included, of which 12 and 10 studies were respectively related to mutation of TNF-α -238G>A, IL-6 -174G>C and URSA. The integrated results showed that the TNF-α-238G>A gene mutation was significantly correlated with the risk of URSA under homozygote model (AA vs GG;OR 1.533,95% CI 1.022-2.301) and recessive model (AA vs GG+AG;OR 1.571,95%CI 1.050-2.350)(P < .05). There was no association between URSA and TNF-α -238G>A under heterozygote model (AG vs GG;OR 0.963,95% CI 0.816-1.137), dominant model (AA+AG vs GG; OR 1.031,95%CI 0.880-1.209) and additive model (A vs G;OR 1.046,95%CI 0.909-1.203)(P > .05). The results of subgroup analysis based on ethnicity showed that -238G>A was significantly correlated with the risk of URSA in Asians under all gene models except for heterozygote model (AG vs GG; OR 1.129,95% CI 0.857-1.487) (P < .05). In Caucasians, it was dominant model (AA+AG vs GG; OR 1.430,95%CI 1.040-1.965) (P < .05) rather than others that showed relationship with URSA. From the integrated results, association was manifested between -174G>C and URSA under all gene models (P < .05) except for recessive model (CC vs GG+CG, OR 1.166, 95%CI 0.938-1.449) (P > .05), which is identical to subgroup analysis based on ethnicity.It is of great guiding significance for screening out and preventing URSA among high-risk women to test on TNF-α -238G>A and IL-6 -174G>C under gene models mentioned above which are highly associated with the risk of URSA, which can act as biological markers for URSA.

Tumour necrosis factor alpha gene polymorphisms in women with recurrent pregnancy loss: a meta-analysis

Tumour necrosis factor alpha (TNF-α) concentration is associated with recurrent pregnancy loss (RPL). Moreover, TNF-α promoter polymorphisms affect cellular TNF-α concentrations. Although several studies on TNF-α polymorphisms have been reported, these studies only define specific loci and result in conflicting conclusions. The meta-analysis in this study was performed to examine the relationship between various TNF-α polymorphisms and RPL. We searched for articles, using MEDLINE and Embase, and performed meta-analysis of 21 studies involving 3437 cases and 4016 controls. The results demonstrated that the -308G/A polymorphism is positively associated with RPL, particularly in cases involving three or more miscarriages. For -1031T/C, -863C/A, and -376G/A polymorphisms, recessive and homozygote models revealed significant associations with RPL. However, -857C/T, -238G/A, and +488G/A polymorphisms showed no association with RPL. A subgroup analysis with respect to ethnicity demonstrated that the -308G/A and -238G/A polymorphisms are associated with RPL in Asian and Middle Eastern populations, respectively. This meta-analysis showed the associations between TNF-α polymorphisms and RPL. However, further studies of genetic polymorphisms in TNF-α other than -308G/A and -238G/A are required.

Association of Tumor Necrosis Factor-α (TNF-α) -308G>A and -238G>A Polymorphisms with Recurrent Pregnancy Loss Risk: A Meta-Analysis

Background

Multiple studies have been carried out examining the association of tumor necrosis factor-α gene (TNF-α) promoter region polymorphisms with recurrent pregnancy loss (RPL) risk. However, the results remain controversial and incomplete. Hence, we performed a meta-analysis to evaluate the association of the TNF-α -308G>A and -238G>A polymorphisms with RPL risk.

Materials and Methods

In this meta-analysis, a comprehensive search of PubMed, Web of Knowledge and EMBASE was performed to identify relevant studies published until December 1, 2017. The associations were assessed by odds ratio (OR) and its corresponding 95% confidence interval (CI).

Results

A total of 29 case-control studies, comprising 20 studies on TNF-α -308G>A (3,461 cases and 3,895 controls) and nine studies on TNF-α -238G>A (2,589 cases and 2,664 controls), were included in the meta-analysis. Overall, we found TNF-α -308G>A to be associated with an increase in RPL risk under the homozygote (OR=1.716, 95% CI: 1.210-2.433, P=0.002) and the recessive (OR=1.554, 95% CI: 1.100-2.196, P=0.012) models. TNF-α -238G>A was also significantly associated with increased risk of RPL under the allele model (OR=1.554, 95% CI: 1.100-2.196, P=0.012). Stratified analysis revealed a more significant association between theTNF-α -308G>A polymorphism and increased RPL risk in Asians under the homozygote (OR=2.190, 95% CI: 1.465-3.274, P≤0.001), the dominant (OR=1.642, 95% CI: 1.269-2.125, P≤0.001) and the recessive (OR=1.456, 95% CI: 1.039-2.040, P=0.029) models, but not in Caucasians. A non-significant association was, however, identified between TNF-α -238G>A and RPL risk based on ethnicity. Moreover, TNF-α -308G>A and -238G>A polymorphisms were significantly associated with increased risk of RPL in high quality studies and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) subgroups.

Conclusion

The present meta-analysis demonstrates that TNF-α -308G>A and -238G>A polymorphisms are associated with an increased risk of RPL.

Mitochondrial DNA variations are associated with recurrent pregnancy loss

Cases with three or more consecutive spontaneous abortions before the 20th week of gestation are termed as recurrent pregnancy loss (RPL). Problems in implantation of the foetus and any retarded growth of the foetus in the uterus can be correlated to RPL. Possible causes of RPL would include the genetic variations in the regulatory enzymes of the crucial metabolic pathways, clotting factors, hormones and hormone receptors. This defect of the mitochondrial respiratory chain is recognized as a major cause of human disease. We investigated 73 women with RPL and 100 healthy normal controls. By using the direct sequencing method, the amplified products including the mtDNA complex I genes were analyzed. Overall, seven variations in mitochondrial complex I genes were found (T4216C, A5153G, C10142T, C12062T, A12662G, G14179A and T14263C) using direct sequencing technique. The RPL group had significantly higher proportions of the different variants than those observed of the control group. In conclusion, more research is essentially needed to understand the effect and role of the mitochondrial variations in the progress of RPL, which may vary among individuals and different ethnic groups.

Genetics of recurrent miscarriage and fetal loss

Despite years of research, miscarriage, particularly when recurrent, continues to pose a medical challenge. An embryo chromosomal error is responsible for 50-60% of recurrent cases; however, up to 30-50% remains an enigma. Successful pregnancy involves different maternal physiologic changes and certain complex interactions between the fetus and the mother by cytokines, angiogenic mediators and hormones. To date, research lines have focused on genetic and epigenetic polymorphisms related mainly to immune response and inflammatory mediators, and have yielded a significant relationship between recurrent miscarriage and immune mechanisms. Thus, unknown causes of miscarriage could be due to an immune imbalance induced by T-helper Th1/Th2/Th17 cytokines and regulatory T cells. Furthermore, these genes and mediators have long been suspected of being blood markers for the clinical diagnosis and management of miscarriage; however, more evidence is required for them to be included in medical practice and obstetric guidelines.

Low-Grade Metabolically-Induced Inflammation Mediators Interleukin-6, Adiponectin, and TNF-α Serum Levels in Obese Pregnant Patients in the Perinatal Period

Background

Obesity is a major clinical problem. The number of obese pregnant women is rising rapidly. The consequences of obesity are significant and affect every aspect of perinatal care for both the mother and the developing fetus. Adipose tissue may be responsible for chronic subclinical inflammation in obesity, being a source of inflammatory mediators. The study was designed to evaluate the analysis of the serum concentration of inflammatory mediators, including interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and adiponectin, in obese pregnant women at full-term pregnancies.

Material/Methods

The study included 40 women with body mass index (BMI) less than 30 and 24 pregnant women with BMI equal to or greater than 30, admitted to the Perinatology and Obstetrics Department of the University Hospital in Cracow in the first stage of labor. Blood samples were taken from patients to detect the serum concentration of cytokines. Ultrasound was used to evaluate the development of the fetus, including estimated fetal weight, Doppler flows, and the amount of amniotic fluid. We also included the history of chronic diseases and other complications of the pregnancy. A p-value <0.05 was considered significant.

Results

The level of adiponectin in obese patients as compared to controls was significantly lower. There was no statistically significant difference in either group when TNF-α and IL-6 were measured. The results of the survey are consistent with previous reports.

Conclusions

The exact role of inflammation in pregnancy is not well understood. Determining the exact functions of the different cytokines in physiological pregnancy and pregnancy complicated by obesity requires further study.

No Association between TNF-α -308G/A Polymorphism and Idiopathic Recurrent Miscarriage: A Systematic Review with Meta-Analysis and Trial Sequential Analysis

Background

Conflicting results were reported on the association between the TNF-α -308G/A polymorphism and idiopathic recurrent miscarriage (IRM). Though three meta-analyses have been conducted on this topic, the conclusions were contradictory, and the results may be unreliable as certain crucial conditions were neglected.

Method

A complete search was conducted in PubMed, Cochrane Library, and Embase, other sources like Google Scholar, ClinicalTrial.gov and reference lists of relevant articles were also retrieved. All candidate articles were accessed and screened using specific inclusion and exclusion criteria. Statistical analyses were performed on data extracted from eligible studies using the STATA 12.0 software and the TSA 0.9 beta software.

Results

Eventually, 12 case-control studies from 11 publications (with 1,807 cases and 2,012 controls) were included in this meta-analysis, and no evidence of any significant association was found in the overall analyses between the TNF-α -308G/A polymorphism and IRM risk. However, significant association was shown in Asian population (four studies from three publications) in the dominant model (AA + GA vs. GG), the allelic model (A vs. G), and the heterozygote model (GA vs. GG).

Conclusions

TNF-α -308G/A polymorphism is not associated with IRM risk. Though significant association was found in Asian population, the result needs further confirmation from more studies.

Interaction with angiotensin-converting enzyme-encoding gene in female infertility: Insertion and deletion polymorphism studies

Angiotensin-converting enzyme (ACE), a key enzyme in the renin– angiotensin–aldosterone system, converts angiotensin I to angiotensin II. Ethnic origin should be carefully considered in studies pertaining to ACE I/D genotype and disease etiology. This study was evaluated between the ACE gene I/D polymorphism and female infertility in the Saudi population. Out of a A total of 300 women who participated in this study genomic DNA samples from the 150 infertile and 150 fertile women’s were isolated who has participated in this study. Genomic DNA was isolated using an Invitrogen kit according to the manufacturer’s protocol, and D allele specific primers were used for amplification by polymerase chain reaction. Electrophoresis was carried out on a 2% agarose gel. The mean age and BMI of the cases and controls were similar (p > 0.05), and a significant association was noted between the family history and female infertility (p = 0.0001). The D allele (OR: 1.67 [95% CI: 1.18–2.35], p = 0.003), DD genotype (OR: 2.46 [95% CI: 1.20–5.02], p = 0.01) and dominant model (OR: 1.97 [95% CI: 1.00–3.88], p = 0.04) were significantly associated with female infertility or fertility. The results of this study show that the ACE polymorphism plays an important role in female infertility in the Saudi population.