Unveiling the pathophysiology of gestational diabetes: Studies on local and peripheral immune cells.

Gestational diabetes mellitus (GDM) has been associated with impaired maternal immune response. Our aim was to review the available literature linking immune cells profile to GDM, in order to comprehend the role that different subpopulations play in the development of this pathology. We searched in PubMed for studies published in the last decade on circulating levels and placenta expression of immune cells on GDM. We identified 18 studies with several differences regarding the study design, clinical characteristics, number of participants, cell subpopulation and type of sample. Most studies assessed only one subpopulation either in peripheral blood or placenta and did not analyse functional properties of the cells. The most frequently evaluated immune cells were T lymphocytes, especially regulatory T (Tregs), and natural killer (NK) cells in the peripheral blood, and placental macrophages. No studies analysing B cells were identified, and only one study each evaluating γδT cells, dendritic cell (DC) and monocytes was found. Although there are controversies, at least one study reported positive association between GDM and CD4+ (activated), Tregs, Th17 and γδT cells; neutrophil/lymphocyte; NK cell (cytotoxic); macrophages; and monocytes. The number of studies is still small, so caution should be exercised in interpreting the data, and further research is required to validate these findings and establish the role of adaptive and innate immune cells in GDM pathophysiology.

Angiogenic factors and uterine Doppler velocimetry in early- and late-onset preeclampsia.

OBJECTIVE: To assess correlations between maternal serum levels of pro- and anti-angiogenic factors with uterine perfusion in women with early- compared with late-onset preeclampsia, and in healthy pregnant women. DESIGN: Case-control study. SETTING: Antenatal care clinic located within a hospital (São Bernardo do Campo, Brazil). POPULATION: We enrolled 54 preeclamptic and 54 healthy control women who were coming for routine ultrasound at 28-36 weeks' gestation. METHODS: All participants had uterine artery and umbilical Doppler studies and a blood sample to assess maternal serum levels of soluble fms-like tyrosine kinase-1, soluble endoglin, adiponectin and plasminogen activator inhibitor-1. All angiogenic factors were measured using enzyme-linked immunosorbent assay. MAIN OUTCOME MEASURES: Levels of pro- and anti-angiogenic factors in maternal serum, and uterine artery Doppler findings. RESULTS: Concentrations of soluble fms-like tyrosine kinase-1 and soluble endoglin were significantly higher in preeclamptic than control women (p < 0.0001 and p < 0.0001, respectively), especially in those with early-onset (<34 weeks) preeclampsia. These two anti-angiogenic mediators were significantly correlated with increased uterine artery Doppler in the preeclamptic women. Plasminogen activator inhibitor-1 levels were significantly higher in preeclampsia (p = 0.03) but unrelated to uterine artery resistance. Adiponectin levels were similar in cases and controls, independent of body mass index and unrelated to uterine artery resistance. CONCLUSION: Preeclamptic patients have increased soluble fms-like tyrosine kinase-1 and soluble endoglin serum levels and this increase is directly correlated with uterine artery resistance, especially in those with early-onset preeclampsia.

Immunoregulatory gene polymorphisms in women with preeclampsia.

The costimulatory molecules CD28, cytotoxic T-lymphocyte antigen-4 (CTLA-4) (cytotoxic T-lymphocyte-associated antigen-4) and inducible costimulator (ICOS) are believed to have a critical modulatory role in the immune response. However, few studies have been performed on the role of these immune regulatory molecules and their polymorphisms in women with preeclampsia (PE). The aim of our study was to evaluate the CTLA4 (+49 A/G) (rs 231775), CD28 (+17 T/C) (rs 3116496) and ICOS (-1564 T/C) (rs 4675378) gene polymorphisms in Brazilian women with PE. This case-control study included 130 patients with PE and 261 control women without any obstetric or systemic disorders. Genomic DNA was extracted from peripheral blood, and the polymorphism genotyping was performed by digesting the PCR products with the restriction endonucleases BbvI (CTLA-4), AfeI (CD28) and AluI (ICOS). Data were analyzed by χ(2) or Fisher's exact test; a P-value of <0.05 was considered as significant. There were significant differences in the ICOS genotype and allelic frequencies between the PE and control groups (P=0.01 and P=0.01, respectively). We found a significantly lower frequency of the ICOS (-1564) T allele in women with mild PE compared with the controls. There were no differences in the CTLA-4 (+49 A/G) and CD28 (+17 T/C) genotypes and allelic frequencies between the PE patients and controls. Our data suggest that PE is associated with ICOS, but is not associated with the CTLA-4 or CD28 gene polymorphisms.

Inflammatory mediators gene polymorphisms in preeclampsia.

OBJECTIVE: To assess a possible relation between proinflammatory mediators (IL-1R1, IL-12, IL-18, TLR-2, and TLR-4) gene polymorphisms and preeclampsia (PE). METHODS: Genotyping was performed on 109 preeclamptic patients and 174 healthy fertile women with at least two previous successful pregnancies (controls). χ(2) or Fisher's exact test were used to compare genotype frequencies. The control group included 174 pregnant women matched by race to the study group. RESULTS: Genotypic and allelic distributions for all six polymorphisms were similar between the study and control groups. IL-1R1 (PstI, rs2234650): p = 0.82 ; IL-12 (+1188, rs3212227): p = 0.93; IL-18 (-137, rs187238): p = 0.74 ; IL-18 (-607, rs1946519): p = 0.22; TLR-2 (+2258, rs5743708): p = 0.97; and TLR-4 (+896, rs4986790): p = 0.23. CONCLUSION: The analyzed gene polymorphisms are not associated with PE.

Tissue-specific expression of IL-15RA alternative splicing transcripts and its regulation by DNA methylation.

The human IL-15RA gene encoding the alpha chain of the IL-15 receptor is expressed in a variety of immune and non-immune cell types from different tissues, and generates multiple splicing events of functional importance. We aimed to evaluate expression of IL-15RA transcripts generated by alternative usage of transcription start site (Var1 and Var2) and by deletion of exon 3 (Del3), exon 2 (Del2), or both (Del2,3) in different human tissues. Since a CpG island was found near to the IL-15RA gene transcription start site, we also investigated the role of DNA methylation on the expression of IL-15RA full-length and alternative transcripts fragments in peripheral blood mononuclear cells (PBMC). IL-15RA transcription of functional (full-length and del 3) and non-functional (del 2 and del 2,3) variants was detected in many tissues, however, the number of different IL-15RA transcripts variants detected in each tissue did not correlate with the level of gene expression. IL-15RA transcript variants Var1 and Var2 presented similar expression levels in different human tissues. However, we found a distinct expression profile of functional and non-functional IL-15RA transcripts fragments. A preferential expression of transcripts that bind IL-15 compared to IL-15 non-binding transcripts was seen in the tissues investigated. When PBMC cultures were treated with 5-azacitidine (AZA), a DNA methyltransferase inhibitor, we detected a significant increase in IL-15RA copy number. Only alternative exon skipping events of Var1 (Del 2, Del 3 and Del 2, 3) were altered by AZA treatment, which is consistent with the CpG island localization in the regulatory region 5' upstream of the transcription start site of Var1 and not of Var2. Therefore, this work shows a broad expression pattern of functional IL-15RA splicing forms and suggests a regulatory role of DNA methylation in IL-15RA transcript Var1 expression in mononuclear cells.