Associations of Adipose Tissue Architecture, Adipokines and Inflammatory Markers with Body Mass Index and Gestational Weight Gain in Non-diabetic Pregnancies

Background: Some pregnancy weight gain is stored as adipose tissue (AT). Human AT depots vary in their capacity for expansion. Data suggests that subcutaneous (SQ) is adapted for healthy lipid storage. Conversely visceral (V) accumulation is associated with inflammation, obesity-related co-morbidities and Type 2 diabetes (T2DM) risk. We investigated SQ and VAT histologic architecture along with insulin, adipokines and inflammatory markers in relationship to prepregnancy BMI and gestational weight gain (GWG). Methods: Subset of non-diabetic singleton gravidas from the Pregnancy & Postpartum Observational Dietary Study (PPODS), undergoing Cesareans and consenting to SQ & VAT biopsies were included. Average adipocyte size assessed in10 sections/depot/subject. Maternal and cord blood insulin, adiponectin, leptin, PAI-1, CRP, TNFα, IL1b, IL6 and IL8 evaluated using Luminex MAGPIX, laser based fluorescent analytical test instrumentation with MILLIPLEX® multi-analyte panels. GWG determined by difference in pre-pregnancy and last prenatal visit weight. Results: Of 110 subjects enrolled, 19 (17.3%) delivered by Cesarean with 14 consenting to AT sampling, and 7 (50%) having both SQ and VAT available for analysis. These 7 had mean pre-pregnancy BMI 27.8±5.6 kg/m2 and GWG 50.0±25.7 lb (range 19-83) with delivery age 39.2±0.7 wks. Mean SQ and VAT adipocyte sizes were 2892±716 pixels2 (range 1866-3775) and 2427±641 pixels2 (range 1416-3397) respectively (p=0.310); neither were statistically correlated with BMI or GWG. Pre-pregnancy BMI statistically correlated with maternal serum insulin (0.786, p=0.036) at delivery and cord blood leptin (0.886, p=0.019); GWG statistically correlated only with cord blood adiponectin (-0.900, p=0.037). Conclusions: In a small sample of normoglycemic pregnancies undergoing Cesareans and AT sampling, adipocyte size was no different in SQ versus visceral depots, and did not correlate with BMI or GWG. Surprisingly, pre-pregnancy BMI but not GWG correlated with maternal serum insulin at delivery, suggesting that pre-pregnancy weight status may be associated with glycemic control at pregnancy end

A role for uric acid and the nalp3 inflammasome in antiphospholipid antibody-induced IL-1β production by human first trimester trophoblast

Women with antiphospholipid syndrome (APS) are at risk of recurrent pregnancy loss and obstetrical disorders, such as preeclampsia and intrauterine growth restriction (IUGR). Antiphospholipid antibodies (aPL) directly target the placenta by binding beta(2)-glycoprotein I (beta(2)GPI) expressed on the trophoblast. We recently demonstrated in human first trimester trophoblast cells that anti-beta(2)GPI antibodies (Abs) induce the secretion of IL-1 beta in a Toll-like receptor 4 (TLR4)-dependent manner. IL-1 beta secretion requires processing of pro-IL-1 beta and this is mediated by the inflammasome, a complex of Nalp3, apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1. The objective of this study was to determine if aPL induce IL-1 beta production in trophoblast via the inflammasome. Using a human first trimester trophoblast cell line, we demonstrated that a mouse anti-beta(2)GPI mAb and human polyclonal aPL-IgG induce IL-1 beta processing and secretion, which was partially blocked upon caspase-1 inhibition. Nalp3 and ASC knockdown also attenuated anti-beta(2)GPI Ab-induced IL-1 beta secretion. Furthermore, aPL stimulated the production of uric acid in a TLR4-dependent manner; and inhibition of uric acid prevented aPL-induced IL-1 beta production by the trophoblast. These findings demonstrate that aPL, via TLR4 activation, induce a uric acid response in human trophoblast, which in turn activates the Nalp3/ASC inflammasome leading to IL-1 beta processing and secretion. This novel mechanism may account for the inflammation at the maternal-fetal interface, which causes placental dysfunction and increases the risk of adverse pregnancy outcome in patients with APS

Antiphospholipid antibody-induced trophoblast IL-1β is dependent on ASC and Nalp3.

<p>Trophoblast transfected to express either (A &amp; C) shRNA for ASC (sh-ASC) or a control sequence (sh-control) (n = 5); or (B &amp; D) shRNA for Nalp3 (sh-Nalp3) or a Nalp3 mutated targeting sequence (Nalp3-mut) (n = 4), were either not treated (NT) or treated with the anti-β₂GPI mAb, IIC5 (20 µg/ml) for 72 hrs. Culture supernatants were measured for (A &amp; B) IL-1β and (C &amp; D) IL-8 by ELISA. *<i>p</i>&lt;0.05; **<i>p</i>&lt;0.001 versus the NT control, unless indicated otherwise.</p

Antiphospholipid antibody-induced trophoblast IL-1β is dependent upon caspase-1.

<p>Trophoblast cells were either not treated (NT) or treated with the anti-β₂GPI mAb, IIC5 (20 µg/ml), all in the presence of media or the caspase-1 inhibitor (5 µM) for 72 hrs. (A) Active IL-1β (17 kDa) expression was evaluated by Western blot. (B) Barchart shows IIC5-induced IL-1β secretion as determined by ELISA and expressed as fold change relative to the untreated control. Data are from 4 independent experiments (*<i>p</i>&lt;0.05).</p

Uric acid levels in serum from aPL⁻ and aPL⁺ PROMISSE patients at 20–23 weeks gestation.

*<p>Based on Mann-Whitney <i>U</i> test.</p

Antiphospholipid antibodies induce trophoblast IL-1β processing and secretion.

<p>Trophoblast cells were either not treated (NT) or treated with (i) the anti-β₂GPI mAb, IIC5 (20 µg/ml) or mouse IgG1 control (mIgG; 20 µg/ml); or (ii) human aPL-IgG (500 µg/ml) or normal human IgG control (hIgG; 500 µg/ml) for 72 hrs. (A) Barcharts show levels of secreted IL-1β as determined by ELISA. Data are from 5 independent experiments. *<i>p</i>&lt;0.01 versus the NT control. (B) Trophoblast cells were evaluated for active IL-1β (17 kDa) expression by Western blot (representative blots are shown). Barcharts below show quantification of protein expression as determined by densitometry and normalized to β-actin. Data are from 3 independent experiments. *<i>p</i>&lt;0.05 versus the NT control.</p

Human adipose tissue expansion in pregnancy is impaired in gestational diabetes mellitus

AIMS/HYPOTHESIS: During pregnancy, adipose tissue (AT) must expand to support the growing fetus and the future nutritional needs of the offspring. Limited expandability of AT is associated with insulin resistance, attributed to ectopic lipid deposition. This study aimed to investigate human AT expandability during pregnancy and its role in the pathogenesis of gestational diabetes mellitus (GDM). METHODS: This cross-sectional study of omental (OM) and subcutaneous (SQ) AT collected at Caesarean delivery included 11 pregnant and three non-pregnant women with normal glucose tolerance (NGT), five with GDM, three with type 2 diabetes mellitus. Adipocyte size, capillary density, collagen content and capillary growth were measured. Affymetrix arrays and real-time PCR studies of gene expression were performed. RESULTS: Mean OM adipocyte size was greater in women with GDM than in those with NGT (p = 0.004). Mean OM and SQ capillary density was lower in GDM compared with NGT (p = 0.015). Capillary growth did not differ significantly between groups. The most differentially expressed AT transcript when comparing non-pregnant and pregnant women corresponded to the IGF binding protein (IGFBP)-5, the expression levels of which was found by subsequent quantitative real-time PCR to be lower in women with GDM vs women with NGT (p \u3c 0.0001). CONCLUSIONS/INTERPRETATION: The relative OM adipocyte hypertrophy and decreased OM and SQ capillary density are consistent with impaired AT expandability in GDM. The induction of adipose tissue IGFBP5 in pregnancy and its decrease in GDM point to the importance of the IGF-1 signalling pathway in AT expansion in pregnancy and GDM susceptibility