Silvia Daher

Associations between cytokine gene polymorphisms and recurrent pregnancy loss

Since certain cytokines may play a role in unexplained recurrent pregnancy loss (RPL) and also some cytokine gene polymorphisms may affect the level of cytokine production, the aim of the present study was to investigate the relationship between RPL and polymorphisms of the genes coding for TNF-alpha (-308 G-->A), IL-10 (-1082 G-->A), IL-6 (-174 G-->C), and IFN-gamma (+874 A-->T). Genotyping was performed in 48 RPL women and 108 ethnically matched healthy individuals. In addition, we performed a meta-analysis encompassing the present results and those from studies on the association of TNF-alpha, IL-10 and IFN-gamma polymorphisms with RPL published in the literature until December 2001. The results showed: (1) no evidence of association with IL-6 gene polymorphisms; (2) significant associations, revealed by the meta-analysis, with the high cytokine production genotypes of IFN-gamma (+874 T/T: odds ratio (OR)=1.92, P=0.04) and IL-10 (-1082 G/G: OR=1.75, P=0.03), and a trend for association with the high TNF-alpha production genotypes -308 A/A and A/G (OR=1.61; P=0.18). We believe that the associations of these genotypes with RPL are interesting not only as risk factors but also because they represent another piece of evidence that these cytokines might be important in the pathogenesis of RPL.

Maternal BMI and preterm birth: A systematic review of the literature with meta-analysis

Objectives. To examine the association between high prepregnancy maternal body mass index (BMI) and the risk of preterm birth (PTB). Methods. A systematic review of the literature. We included cohorts and case-control studies published since 1968 that examined the association between BMI and PTB of all types, spontaneous (s), elective and with ruptured membranes (PPROM) in three gestational age categories: general (<37 weeks), moderate (32–36 weeks) and very (<32 weeks) PTB. Results. 20,401 citations were screened and 39 studies (1,788,633 women) were included. Preobese (BMI, 25–29.9) and obese I (BMI, 30–34.9) women have a reduced risk for sPTB: AOR = 0.85 (95% CI: 0.80–0.92) and 0.83 (95% CI: 0.75–0.92), respectively. Their risk for moderate PTB was 1.20 (95% CI: 1.04–1.38) and 1.60 (95% CI: 1.32–1.94), respectively. Obese II women (BMI, 35–40) have an increased risk for PTB in general (AOR = 1.33, 95% CI: 1.12–1.57) moderate (AOR = 2.43, 95% CI: 1.46–4.05) and very PTB (AOR = 1.96, 95% CI: 1.66–2.31). Obese III women (BMI > 40) have an even higher risk for very PTB (AOR = 2.27, 95%CI: 1.76–2.94). High BMI does not modify the risk for PPROM and increases the risk for elective PTB. Conclusions. High maternal BMI may have different effects on different types of PTB.

Cytokine genotyping in preeclampsia.

Problem  Considering that cytokines are involved in preeclampsia (PE) pathogenesis and that cytokine gene polymorphism may affect cytokine production, our purpose was to investigate the association of PE with tumor necrosis factor (TNF)‐α (−308), transforming growth factor‐β1 (+10; 25), interleukin (IL)‐10 (−1082), IL‐6 (−174), and interferon‐γ (+874) polymorphisms.

Cow's milk protein intolerance and chronic constipation in children

Cows milk protein (CMP) allergy was investigated in 25 children (age‐range 3 months to 11 years) with chronic constipation. A diagnosis of constipation was made on the basis of a history of painful elimination of hard stools for at least 1 month, whether or not associated with a reduced frequency of stools or soiling. The children were evaluated using clinical parameters and the following laboratory tests: total serum immunoglobulin E (IgE); specific IgE (radioallergosorbent test [RAST]) for whole cows milk, α‐lactoalbumin, β‐lactoglobulin, and a food group; and skin‐prick tests with whole milk, α‐lactoalbumin, β‐lactoglobulin, and casein. Following the evaluation, the children were submitted to a CMP‐free diet for a period of 4 weeks. In seven patients (28%), constipation disappeared during the CMP‐free diet and reappeared within 48–72 h following challenge with cows milk. In two infants a rectal biopsy revealed allergic colitis and they therefore did not undergo the challenge. High serum levels of total IgE were observed in five of the children who showed a clinical improvement (71%), a positive skin‐test in two (29%), and detectable specific IgE in two (29%). These results suggest that CMP allergy or intolerance should be considered as a cause of chronic refractory constipation in children, although the underlying mechanism still require further investigation.

Tumor necrosis factor during pregnancy and at the onset of labor and spontaneous abortion

OBJECTIVE The aim of this study was to evaluate the production of tumor necrosis factor (TNF) by peripheral blood cells during pregnancy, at the onset of labor and of spontaneous abortion (SA), as well as in non-pregnant women with and without a history of recurrent spontaneous abortions (RSA). STUDY DESIGN The peripheral blood cells TNF production was evaluated in 28 women in the 1st trimester of pregnancy, 21 in the 2nd, and 30 in the 3rd, 47 at term labor; 43, at the onset of SA; 19 healthy and 19 RSA non-pregnant women. The statistical method used was the Mann-Whitney test. RESULTS We observed (1) lack of TNF detection in the 1st gestational trimester; (2) increase of TNF production with gestational age, with the highest values being observed at labor (P<0.05); (3) high TNF production at the onset of SA; (4) no difference in the TNF production by healthy and RSA non-pregnant women. CONCLUSIONS The suppression of TNF production during the 1st trimester of pregnancy seems to favor the normal development of pregnancy. It remains to be investigated whether the assessment of TNF production is a valuable prognostic parameter for the occurrence of abortion.

Inflammatory cytokine gene polymorphisms and spontaneous preterm birth

The objective was to search for an association between spontaneous preterm birth (sPTB) and single and/or combined polymorphisms in genes TNFA -308 G>A, IL10 -1082 G>A, IL10 -819 C>T, IL10 -592 C>A, IL6 -174 G>C, and IFNG +874 A>T. Genotyping was performed on 410 Brazilian ethnically matched women managed at two hospitals (two independent case-control sets). One set consisted of 122 cases and 101 controls, and the other set comprised 82 cases and 105 controls. We compared genotype and genotype-combination frequencies between cases and controls using Fishers exact or the chi(2) tests and confirmed results using logistic regression. Among the six SNPs studied, we found no independent association between any single SNP and sPTB risk. The multi-locus analysis revealed a significant association between sPTB and the TNFA(GG)/IL6(GG)/IFNG(AA) genotype combination (p=0.002), confirmed by logistic regression. Our data suggest that the combination of TNF-alpha, IFN-gamma, and IL-6 maternal gene polymorphisms might contribute to susceptibility to sPTB. This finding could be investigated as a possible genetic marker for the risk of spontaneous preterm birth.

Genetic Polymorphisms and Recurrent Spontaneous Abortions: An Overview of Current Knowledge

The relevance of gene polymorphisms in the development of unexplained recurrent spontaneous abortion is still unclear. Cytokines, angiogenic mediators, and hormones are involved in all stages of reproduction and pregnancy outcome. Impaired production and/or unbalanced ratios of these mediators have been implicated in the pathogenesis of unexplained recurrent spontaneous abortion. Functional polymorphism influence gene activity and therefore can interfere with the expression of mediators. Several studies have been carried out to evaluate the relationship between cytokines, angiogenic mediators, and hormones gene polymorphisms and unexplained recurrent spontaneous abortion. The results of these studies are mostly contradictory, and few significant associations have been identified. Up to present time, the evidence is insufficient to support the evaluation of cytokines, angiogenic mediators, and hormones gene polymorphism in routine workup in all cases of recurrent pregnancy loss, and these tests are not included in any of the major obstetric guidelines.

Cytokine gene polymorphisms in preeclampsia and eclampsia

The clinical spectrum of preeclampsia (PE) ranges from mild hypertension to severe vasospasm associated with convulsions and multiple organ damage. The biological factors that determine the progression of PE to eclampsia (E) are unknown. Endothelial cell activation seems related to an impaired maternal immune response. The production of cytokines, IL-10 and TGF-β1, is apparently suppressed, and altered IL-2/IL-10 and TNF-α/IL-10 ratios have been reported in preeclamptic cases. The relationship between PE and cytokine gene polymorphism has been studied, but there are few studies that include eclamptic patients. This study aimed at investigating whether polymorphisms in genes, TNF-α promoter (−308 G>A), IL6 promoter (−174 G>C), IFN-γ intron 1 (+874 A>T), IL10 promoters (−1082 A>G), (−819 C>T) and (−592 C>A) and TGF-β1 codon 10 (+869 T>C) and codon 25 (+915 G>C) are associated with E and/or PE. Genotyping was carried out in 266 Mulatto women from the northeastern region of Brazil who were referred to a single maternity hospital: 92 with PE, 73 with E and 101 normotensive controls. The χ2 or Fishers exact tests were used to compare genotype frequencies. Among the six single-nucleotide polymorphisms (SNPs) studied, we found no difference in genotype frequencies between the groups. There was a higher frequency of IFN-γ (+874 A) in eclamptic patients in comparison with that in controls. (70.3 vs. 57.8%, respectively; P=0.02). There were no other significant differences in allelic frequencies between eclamptic, preeclamptic and control groups We found no independent association between any single SNP and PE or E risk in this population of Mulatto women from the northeastern region of Brazil.

Cytokine Levels in Gestational Diabetes Mellitus: a Systematic Review of the Literature

Gestational diabetes mellitus (GDM) is an inflammatory condition that involves unbalanced cytokine production. We carried out a systematic review on the relationship between GDM and maternal circulating levels of cytokines in the 2nd/3rd trimesters.

Vascular endothelial growth factor (VEGF) and VEGF-receptor expression in placenta of hyperglycemic pregnant women

Hyperglycemia occurs in a variety of conditions such as overt diabetes, gestational diabetes and mild hyperglycemia, all of which are generally defined based on the oral glucose tolerance test and glucose profiles. Whereas diabetes has received considerable attention in recent decades, few studies have examined the mechanisms of mild hyperglycemia and its associated disturbances. Mild gestational hyperglycemia is associated with macrosomia and a high risk of perinatal mortality. Morphologically, the placenta of these women is characterized by an increase in the number of terminal villi and capillaries, presumably as part of a compensatory mechanism to maintain homeostasis at the maternal-fetal interface. In this study, we analised the expression of VEGF and its receptors VEGFR-1 (Flt-1) and VEGFR-2 (KDR) in placentas from mildly hyperglycemic women. This expression was compared with that of normoglycemic women and women with gestational and overt diabetes. Immunohistochemistry revealed strong staining for VEGF and VEGFR-2 in vascular and trophoblastic cells of mildly hyperglycemic women, whereas the staining for VEGFR-1 was discrete and limited to the trophoblast. The pattern of VEGF and VEGF-receptor reactivity in placentas from women with overt diabetes was similar to that of normoglycemic women. In women with gestational diabetes, strong staining for VEGFR-1 was observed in vascular and trophoblastic cells whereas VEGF and VEGFR-2 were detected only in the trophoblast. The expression of these proteins was confirmed by western blotting, which revealed the presence of an additional band of 75 kDa. In the decidual compartment, only extravillous trophoblast reacted with all antibodies. Morphological analysis revealed collagen deposition around large arteries in all groups with altered glycemia. These findings indicate a placental response to altered glycemia that could have important consequences for the fetus. The change in the placental VEGF/VEGFR expression ratio in mild hyperglycemia may favor angiogenesis in placental tissue and could explain the hypercapillarization of villi seen in this gestational disturbance.