Abdominal Adiposity and Insulin Resistance in Early Pregnancy

Gestational diabetes mellitus early prediction by maternal body fat index: A cohort study

OBJECTIVES

To compare the performance of maternal body fat index (BFI) assessed during the first 20+6 weeks among 138 pregnant women in an ultrasound outpatient clinic as a predictor of gestational diabetes mellitus (GDM) later in pregnancy.

METHOD

Maternal visceral and subcutaneous fat was measured with a convex ultrasound probe placed in two locations on the maternal abdominal surface: the first in the mid-sagittal epigastric region, visualising epigastric fat, and the second 2cm above the maternal umbilical scar, visualising periumbilical fat. Ultrasound callipers measured the distance from dermal edge to the linea alba and after from the linea alba to the anterior hepatic surface (epigastric fat). Periumbilical fat was measured from the dermal edge to the linea alba and after from the linea alba to the anterior aortic surface. The BFI formula was [visceral adipose tissue (mm)×subcutaneous adipose tissue (mm)]/maternal height (cm).

RESULTS

The best thresholds for predicting GDM outcome for epigastric and periumbilical BFI were 1.2 and 4.8, respectively. Odds ratio, sensitivity and specificity were 5.88 (95% CI 1.86-18.6), 80.9%, 58.0% for the epigastric site and 6.31 (95% CI 1.73-22.94), 84.2%, 54.2% for the periumbilical site. Pre-pregnancy body mass index compatible with adult obesity shows inadequate predictive performance for GDM outcome. Only epigastric BFI above 1.2 maintained statistical significance for GDM in the logistic regression analysis, when compared to periumbilical BFI above 4.8.

CONCLUSION

Epigastric BFI above 1.2 during the first half of pregnancy may help identify women at risk of developing GDM later in pregnancy.

Evaluating the Adipose Tissue Depth as a Predictor Factor for Gestational Diabetes in Later Pregnancy-A Systematic Review

The increasing prevalence of gestational diabetes mellitus (GDM) requires non-invasive and precise techniques for evaluating the predisposing risk factors such as visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). According to PRISMA, we developed a systematic review and searched after "visceral adipose tissue AND gestational diabetes" and identified 221 articles on the MEDLINE and Word of Science databases. After assessing them for inclusion criteria and two researchers screened them, 11 relevant articles were included. Although evidence is conflicting, more studies favor using US-determined VAT in GDM prediction. VAT may be more valuable than body mass index or SAT in predicting GDM. VAT can represent an additive factor to the prediction tool of the risk of developing GDM when used in conjunction with other anthropometric or biological parameters or maternal risk factors. US measurements are heterogeneous given different evaluation techniques, cut-off values and inter-operator variation. A significant limitation is the lack of a gold standard to identify GDM confidently. Pregnant women may benefit from early monitoring and preventive care if classified as high risk for GDM early in the gestational period. US-measured VAT during the first trimester of pregnancy seems a valuable and inexpensive screening approach to predict GDM development later in pregnancy, either by itself or if used in conjunction with other clinical and biological parameters.

The Association Between Body Fat Index and Gestational Diabetes Mellitus: A Prospective Cohort Study

BACKGROUND

 Body mass index (BMI) has commonly been used to evaluate the risk of gestational diabetes mellitus (GDM), but BMI does not always represent body fat mass distribution. Body fat index (BFI), which includes the measurement of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT), has been suggested to be a better predictor for GDM than BMI.

OBJECTIVE

The objective of this study is to compare the risk of GDM among pregnant females with BFI of >0.5 and ≤0.5.

METHODS

Maternal abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) thickness were measured by ultrasonography before 14 weeks of gestation, and BFI was calculated (VAT×SAT/height). The study group was 160 females with BFI of >0.5, and the comparison group was 80 females with BFI of ≤0.5. All females received GDM screening during the first antenatal visit and at 24-28 weeks of gestation. The rate of GDM was compared between the two groups. The correlation between BFI and BMI and their diagnostic ability for GDM were evaluated. Logistic regression analysis was performed to determine the independent associated factors for GDM.

RESULTS

Females with BFI of >0.5 were significantly older (p=0.033) and had higher body mass index (BMI) (p<0.001) and were more likely to be overweight or obese (p<0.001). BFI correlated well with BMI (correlation coefficient of 0.736, p<0.001). GDM was significantly more common in females with BFI of >0.5 (24.4% versus 11.3%, p=0.017). The diagnostic ability for GDM between BFI and BMI was similar (areas under receiver operating characteristic {ROC} curves of 0.641 and 0.646, respectively). Significant independent risk factors for GDM were a BFI of >0.5 and a BMI of ≥25 kg/m² (adjusted odds ratio {OR}, 3.8; 95% confidence interval {CI}, 1.5-9.2), age of ≥30 years (adjusted OR, 2.8; 95% CI, 1.2-6.4), and family history of diabetes mellitus (DM) (adjusted OR, 4.0; 95% CI, 1.9-8.3).

CONCLUSION

Females with BFI of >0.5 were significantly more likely to have GDM. The diagnostic ability of BFI and BMI for GDM was comparable. Females with BFI of >0.5 and BMI of ≥25 kg/m² have an increased risk for GDM.

Trimester-Specific Serum Fructosamine in Association with Abdominal Adiposity, Insulin Resistance, and Inflammation in Healthy Pregnant Individuals

This study aimed to (1) characterize the variations in serum fructosamine across trimesters and according to pre-pregnancy BMI (ppBMI), and (2) examine associations between fructosamine and adiposity/metabolic markers (ppBMI, first-trimester adiposity, leptin, glucose homeostasis, and inflammation measurements) during pregnancy. Serum fructosamine, albumin, fasting glucose and insulin, leptin, adiponectin, interleukin-6 (IL-6), and C-reactive protein (CRP) concentrations were measured at each trimester. In the first trimester, subcutaneous (SAT) and visceral (VAT) adipose tissue thicknesses were estimated by ultrasound. In the 101 healthy pregnant individuals included (age: 32.2 ± 3.5 y.o.; ppBMI: 25.5 ± 5.5 kg/m2), fructosamine concentrations decreased during pregnancy whereas albumin-corrected fructosamine concentrations increased (p < 0.0001 for both). Notably, fructosamine concentrations were inversely associated with ppBMI, first-trimester SAT, VAT, and leptin (r = −0.55, r = −0.61, r = −0.48, r = −0.47, respectively; p < 0.0001 for all), first-trimester fasting insulin and HOMA-IR (r = −0.46, r = −0.46; p < 0.0001 for both), and first-trimester IL-6 (r = −0.38, p < 0.01). However, once corrected for albumin, most of the correlations lost strength. Once adjusted for ppBMI, fructosamine concentrations were positively associated with third-trimester fasting glucose and CRP (r = 0.24, r = 0.27; p < 0.05 for both). In conclusion, serum fructosamine is inversely associated with adiposity before and during pregnancy, with markers of glucose homeostasis and inflammation, but the latter associations are partially influenced by albumin concentrations and ppBMI.

Exploring comparative assessment of adiposity measures during pregnancy and postpartum

BACKGROUND & AIMS

Excessive adiposity in pregnancy is associated with an altered cardiometabolic profile and adverse maternal and offspring outcomes. Pre-pregnancy body mass index (pBMI) is a proxy measure for adiposity that is most often used in clinical settings; however, it may not identify at-risk pregnancies caused by adiposity-related cardiometabolic dysfunction. The challenge is that validated direct adiposity measures are limited due to the dynamic nature of pregnancy. This exploratory analysis aimed to, 1) evaluate longitudinal changes in % body fat (BF) and the agreement between skinfold thickness (SFT) and bioelectrical impedance analysis (BIA) across pregnancy and in postpartum; 2) compare the discrimination power of SFT, BIA, and pBMI regarding adiposity status; and 3) assess agreement between SFT and BIA with dual-energy X-ray absorptiometry (DXA) in the postpartum.

METHODS

Participants enrolled in the Be Healthy in Pregnancy (BHIP) RCT (NCT01693510) had demographic data and pBMI collected at enrollment and adiposity measured at 12-17, 26-28, and 36-38 weeks gestation by BIA (%BF) and SFT (sum and %BF), and also by DXA at 6 months postpartum. Agreement between methods was assessed by Bland Altman plots and McNemar's test and C-statistic for discriminative power.

RESULTS

In 181 women with mean pBMI of 25.1 kg/m² (min: 17.4 kg/m², max: 39.6 kg/m²) and age 31.6 (SD: 4.0 yr), maternal adiposity increased significantly (p < 0.001) across pregnancy when measured by the sum of SFT or %BF by BIA, but not %BF by SFT. In early pregnancy, BF by BIA and SFT showed good agreement, with BIA values 1.8% greater than SFT, but low agreement in late pregnancy, with BIA values 7.1% greater than SFT. However, in the postpartum, agreement was similar to early pregnancy, and both BIA and SFT demonstrated good agreement with DXA. By pBMI, 45.5% of participants were categorized as overweight/obese, compared to 66.5% by BIA (p < 0.0001) and 54.5% by SFT (p < 0.0001).

CONCLUSIONS

In comparison to SFT and BIA, the results suggest that pBMI is less sensitive in identifying participants with excessive adiposity, limiting its use as a screening tool for adiposity-related adverse outcomes in pregnancy. It would be preferable to use a direct measure of adiposity to screen for at-risk pregnancies. Both %BF by BIA and sum of SFT can quantify the change in adiposity across pregnancy and in the postpartum and thus could be adopted as clinical practice tools. Future research efforts should further refine and validate adiposity techniques for use, particularly in mid and late pregnancy.

CLINICAL TRIAL

The BHIP clinical trial (NCT01693510). REGISTRATION SITE: https://clinicaltrials.gov/ct2/show/NCT01693510.

Evaluation of ultrasound measurements of abdominal fat for the prediction of gestational diabetes in the first and second trimesters of pregnancy

OBJECTIVE

To evaluate whether ultrasound abdominal fat measurements in the first and second trimesters can predict adverse gestational outcomes, particularly gestational diabetes mellitus (GDM), and identify early patients at higher risk for complications.

METHODS

A prospective cohort study of 126 pregnant women at 11-14 and 20-24 weeks of gestation with normal fasting glucose levels during early pregnancy. From 126 participants with complete data, 13.5% were diagnosed with GDM, based on the cutoffs established for the peripherical blood glucose. Subcutaneous, visceral, and maximum preperitoneal abdominal fat were measured using ultrasound techniques. GDM status was determined by oral glucose tolerance test (OGTT) with 75 g glucose overload, and the following values were considered abnormal: fasting glucose ≥92 mg/dl and/or 1 h after overload ≥180 mg/dl and/or 2 h after overload ≥153 mg/dl. The receiver operator characteristic (ROC) curve was used to determine the optimal threshold to predict GDM.

RESULTS

Maximum preperitoneal fat measurement was predictive of GDM, and subcutaneous and visceral abdominal fat measurements did not show significant differences in the prediction of GDM. According to the ROC curve, a threshold of 45.25 mm of preperitoneal fat was identified as the optimal cutoff point, with 87% sensitivity and 41% specificity to predict GDM. The raw and adjusted odds ratios for age and pre-pregnancy body mass index were 0.730 (95% confidence interval [CI], 0.561-0.900) and 0.777 (95% CI, 0.623-0.931), respectively.

CONCLUSION

The use of a 45.25 mm threshold for maximum preperitoneal fat, measured by ultrasound to predict the risk of GDM, appears to be a feasible, inexpensive, and practical alternative to incorporate into clinical practice during the first trimester of pregnancy.

Vitamin D deficiency and visceral adipose tissue in early pregnant women

BACKGROUND

We aimed to assess the correlation between vitamin D serum level and visceral fat tissue during early pregnancy.

METHODS

This cross-sectional study was performed in Pernambuco, Brazil. 190 low risk pregnant women (8-16 gestational weeks) were eligible. Visceral adipose tissue was measured by ultrasonography following the technique described by Armellini. The 25(OH) D in serum was determined through chemiluminescence. The Spearman correlation test was applied to evaluate the correlation between vitamin D serum level and VAT, considering p < 0.05 to be significant.

RESULTS

Vitamin D insufficiency was present in 129 (67.8 %) of subjects. Pregnant women with or without vitamin D deficiency did not differ in age, gestational age, nutritional status and visceral adipose tissue. No correlation between visceral adipose tissue and 25(OH) D was observed: - 0.057 (p = 0.435).

CONCLUSIONS

Maternal visceral adipose tissue and vitamin D serum level are not correlated during pregnancy.

The predictive value of first-trimester anthropometric and ultrasonographic adipose tissue measurements in gestational diabetes mellitus

AIM

Previous studies in pregnant women reported a strong correlation between first-trimester ultrasonographic visceral adipose tissue (VAT) measurements and gestational diabetes mellitus (GDM) during the following weeks. In this study, we aimed to evaluate the clinical utility of ultrasonographic subcutaneous and visceral adipose tissue measurements between 11th and 14th weeks of gestation to predict GDM during the 24th to 28th gestational weeks.

MATERIALS AND METHODS

This prospective study included a total of 142 pregnant women. Between 11th and 14th gestational weeks, we performed blinded measurements of intraperitoneal, perirenal, and subcutaneous adipose tissue thicknesses using ultrasonography. Between 24th and 28th gestational weeks, each participant underwent one-step GDM screening, and the measurement data were assessed for prognostic significance.

RESULTS

Of the 142 women included, 19 (8.8%) were diagnosed with GDM. The mean intraperitoneal and maximum subcutaneous fat thickness were 51.59 ± 22.49 and 19.79 ± 12.52 mm, respectively for the GDM group and 39.88 ± 13.73 and 13.24 ± 5.70 mm, respectively for the non-GDM group. Although we observed statistically significant differences between the GDM and non-GDM groups in terms of current body mass index (BMI), subcutaneous and intraperitoneal fat thicknesses, and waist and hip circumference values, the logistic regression model showed that only current BMI had a significant association with the increasing GDM frequency.

CONCLUSION

In this study investigating the clinical utility of first-trimester ultrasonographic VAT measurements during the 24th to 28th gestational weeks for the diagnosis of GDM, BMI seems to be a more useful predictor than the other anthropometric tools. However, further large-scale studies are needed to confirm these findings.

Maternal Visceral Adipose Tissue and Risk of Having a Small or Large for Gestational Age Infant

OBJECTIVE

To determine whether first-trimester visceral adipose tissue (VAT) depth is associated with small-for-gestational-age (SGA; <10^th percentile) or large-for-gestational-age (LGA; >90^th percentile) birthweight, including when taking into consideration ethnicity-specific birthweight curves.

METHODS

We conducted a prospective cohort study involving 452 women with a singleton livebirth. Maternal VAT depth was measured by ultrasound at 11 to 14 weeks gestation. Newborn weight was plotted on population-based and ethnicity-specific birthweight percentile curves. Modelling was performed using linear and logistic regression, adjusting for parity, smoking status, and weight gain.

RESULTS

Mean maternal age was 32.9 ± 4.7 years, and mean VAT depth was 4.1 ± 1.7 cm. Using a population-based curve, each 1-cm increase in VAT depth was associated with a 1.5 (95% CI 0.03-3.0) higher birthweight percentile. Taking into account ethnicity-specific curves, a 1-cm higher VAT depth was associated with a 1.7 (95% CI 0.02-3.3) greater birthweight percentile. Using a population-based curve, comparing VAT depth Q4 with VAT depth Q1-3, the adjusted odds ratio (aOR) for LGA was 1.9 (95% CI 0.8-4.1); with ethnicity-specific curves, the aOR for LGA was 1.5 (95% CI 0.7-3.2). The aOR for SGA was 0.8 (95% CI 0.4 to 1.7) comparing Q1 with Q2-4 VAT depth.

CONCLUSION

Higher first-trimester maternal VAT depth was associated with a somewhat greater newborn weight percentile, which varies by which birthweight curve is used. There were marginally higher odds of giving birth to an LGA infant for women in highest quartile for VAT depth, with no evident association with SGA.

Maternal Obesity Affects the Glucose-Insulin Axis During the First Trimester of Human Pregnancy

Background and objective: The maternal glucose-insulin axis is central for metabolic adaptations required for a healthy pregnancy. Metabolic changes in obese mothers in early pregnancy have been scantly described. Here we characterized the glucose-insulin axis in the first trimester of human pregnancy and assessed the effect of maternal obesity and fat mass. Methods: In this cross-sectional study, maternal blood samples (N = 323) were collected during voluntary pregnancy termination (gestational age 4+0-11+6 weeks) after overnight fasting. Smokers (N = 198) were identified by self-report and serum cotinine levels (ELISA). Maternal BMI (kg/m2) and serum leptin (ELISA) were used as proxy measures of obesity and maternal fat mass, respectively. BMI was categorized into under-/normal weight (BMI < 25.0 kg/m2), overweight (BMI 25.0-29.9 kg/m2) and obese (BMI ≥ 30.0 kg/m2), and leptin in tertiles (1st tertile: leptin < 6.80 ng/ml, 2nd tertile: leptin 6.80-12.89 ng/ml, 3rd tertile: leptin > 12.89 ng/ml). ISHOMA insulin sensitivity index was calculated from glucose and C-peptide (ELISA) serum concentrations. Analyses of covariance including multiple confounders were performed to test for differences in glucose, C-peptide and ISHOMA between gestational age periods, BMI and leptin groups. C-peptide and ISHOMA were log-transformed before analyses. Results: At weeks 7-9, fasting glucose and C-peptide levels were lower (P < 0.01 and P < 0.001, respectively) and insulin sensitivity higher (P < 0.001) than at weeks 4-6. Glucose levels were not significantly different between BMI or leptin categories. In contrast, C-peptide increased by 19% (P < 0.01) between the normal weight and the overweight group and by 39% (P < 0.001) between the overweight and obese group. In the leptin groups, C-peptide increased by 25% (P < 0.001) between the 1st and 2nd leptin tertile and by 15% (P < 0.05) between the 2nd and 3rd leptin tertile. ISHOMA decreased with higher BMI and fat mass. ISHOMA decreased by 18% (P < 0.01) between the normal weight and the overweight group and by 30% (P < 0.01) between the overweight and the obese group. In the leptin groups, ISHOMA decreased by 22% (P < 0.001) between the 1st and 2nd leptin tertile and by 14% (P < 0.05) between the 2nd and 3rd leptin tertile. Conclusions: At the group level, fasting glucose, C-peptide and insulin sensitivity dynamically change in the first trimester of human pregnancy. Maternal obesity is associated with higher C-peptide and lower insulin sensitivity at all periods in the first trimester of human pregnancy, while glucose is unaltered. These findings have implications for the timing of early gestational diabetes mellitus risk screening.

Maternal visceral adipose tissue during the first half of pregnancy predicts gestational diabetes at the time of delivery - a cohort study

BACKGROUND

Gestational diabetes mellitus (GDM) is a common condition, often associated with high maternal and fetal morbidity. The use of new tools for early GDM screening can contribute to metabolic control to reduce maternal and fetal risk. This study aimed to ascertain whether maternal visceral adipose tissue (VAT) measurement by ultrasound during the first half of pregnancy can predict the occurrence of GDM during the third trimester.

METHODS

A prospective cohort study of 133 pregnant women with gestational age ≤20 weeks in an outpatient setting. VAT depth was measured by ultrasound at the maternal periumbilical region. GDM status was obtained through hospital charts during hospitalization to delivery. A Receiver Operator Characteristic (ROC) curve was used to determine the optimum threshold to predict GDM.

RESULTS

According to the ROC curve, a 45mm threshold was identified as the best cut-off value, with 66% of accuracy to predict GDM. Crude and adjusted odds ratios (OR) for GDM were 13.4 (95%CI 2.9-61.1) and 8.9 (95%CI 1.9-42.2), respectively. A similar result was obtained among pre-gravid non-obese women, with crude and adjusted OR of 16.6 (95%CI 1.9-142.6) and 14.4 (95%CI 1.7-125.7), respectively. Among pre-gravid obese patients, a 45mm threshold did not reach statistical significance to predict GDM.

CONCLUSION

The high and significant OR found before and after adjustments provides additional evidence of a strong association between VAT and GDM. It appears that VAT measurement during the first half of pregnancy has great potential in identifying non-obese women at high risk for GDM. This evidence can assist obstetricians in correctly allocating resources among populations of pregnant women at risk, determined not only by pre-gravid body mass index (BMI).

Ultrasound markers for prediction of gestational diabetes mellitus in early pregnancy in Egyptian women: observational study

INTRODUCTION

Excess visceral adipose tissue (VAT) is associated with insulin resistance in early pregnancy and VAT measurement better explains the association between obesity and insulin resistance than the body mass index. First trimester homeostatic model assessment of insulin resistance (HOMA-IR) or the insulin sensitivity index proved to have positive correlation with late development of gestational diabetes mellitus (GDM) in late pregnancy. Greater VAT depth in the first trimester of pregnancy will be associated with hyperglycemia at 24-28 weeks' gestation.

OBJECTIVES

To study the relationship between abdominal visceral adiposity and insulin resistance in early pregnancy as a predictor for development of GDM in late pregnancy.

PATIENTS AND METHODS

This prospective cohort study included 83 pregnant women at 11-14-week gestation subjected to abdominal adiposity measurement through VAT and subcutaneous adipose tissue (SAT) measurements, then at 16-22 completed a two-hour 75 g OGTT and fasting one-hour and two-hour serum insulin concentration. The HOMA-IR and insulin resistance index (IRI) were calculated. Patients were divided into two groups: group I: pregnant women who did not developed GDM; group 2: pregnant women who developed GDM.

RESULTS

Significant statistical difference in both groups as regarding VAT (p = .001). With mean ± S.D. of VAT increase in Group 2. Mean ± S.D. of HOMA-IR increase in group 2 with significant statistical difference in both groups (p =.001). Also mean ± S.D. of ISI increase in group 2 with significant statistical difference in both groups (p = .001). There was positive relationship between visceral adiposity and HOMA-IR and negative relationship between visceral adiposity and insulin sensitivity. Also, in this study, there was no significant relation between SAT and HOMA-IR.

CONCLUSIONS

From our study, we concluded that measurement of VAT during a routine 11-14 weeks' gestation ultrasound might improve the performance of screening for GDM and correlates with metabolic risk factors even better than BMI.

Ultrasound assessment of maternal adipose tissue during 1st trimester screening for aneuploidies and risk of developing gestational diabetes

INTRODUCTION

The objective of the present study is to compare the sonographic measurement of subcutaneous adipose thickness and visceral adipose thickness during 1st trimester screening for aneuploidies between non-diabetic pregnant women and patients who develop 1st trimester or 2nd trimester gestational diabetes mellitus (GDM).

MATERIAL AND METHODS

Adipose thickness was measured by transabdominal ultrasound imaging in pregnant women attending our clinic for screening for fetal aneuploidies between 11 and 13 weeks of gestation. During the 1st trimester all patients were evaluated for fasting glycemia in accordance with the International Association of Diabetes and Pregnancy Study Groups (IADPSG) recommendations. Patients with confirmed fasting glycemia (FPG) ≥92 mg/dL were diagnosed as 1st trimester GDM. Patients with FPG <92 mg/dL underwent a 75-g oral glucose tolerance test between 24 and 28 weeks.

RESULTS

The study population included 238 non-diabetic women, 29 women with 1st trimester GDM and 28 women with 2nd trimester GDM. Mean subcutaneous adipose thickness and visceral adipose thickness values in non-diabetic women were 9.8 mm (standard deviation [SD = 4.9) and 7.2 mm (SD = 3.5), respectively. Values in women with 1st trimester GDM were 12.8 mm (SD = 6.5) and 9.9 mm (SD = 4.4). In the 2nd trimester GDM group, the mean subcutaneous adipose thickness was 11.1 mm (SD = 4.6) and the mean visceral adipose thickness 10.5 mm (SD = 5.3). Multiple logistic regression analysis showed that visceral adipose thickness, but not subcutaneous adipose thickness, was significantly and independently associated with both 1st trimester GDM (OR 1.15, 95% CI 1.02-1.29) and 2nd trimester GDM (odds ratio [OR] 1.19, 95% confidence interval [CI] 1.05-1.34).

CONCLUSIONS

Sonographic thickness of maternal visceral adipose tissue was greater in women with GDM than in non-diabetic patients, independently of other known risk factors associated with GDM in the 1st and in the 2nd trimester of pregnancy. Thus, this measurement may be considered of clinical use in 1st trimester screening.

Inter and intra-reliability of ultrasonography for the measurement of abdominal subcutaneous & visceral adipose tissue thickness at 12 weeks gestation

BACKGROUND

Excess abdominal adiposity cause metabolic disturbances, particularly in pregnancy. Methods of accurate measurement are limited in pregnancy due to risks associated with these procedures. This study outlines a non-invasive methodology for the measurement of adipose tissue in pregnancy and determines the intra- and inter-observer reliability of ultrasound (US) measurements of the two components of adipose tissue (subcutaneous (SAT) and visceral adipose tissue (VAT)) within a pregnant population.

METHODS

Thirty pregnant women were recruited at the end of their first trimester, from routine antenatal clinic at the University Maternity Hospital Limerick, Ireland. Measurements of adipose tissue thickness were obtained using a GE Voluson E8 employing a 1-5 MHz curvilinear array transducer. Two observers, employing methodological rigour in US technique, measured thickness of adipose tissue three times, and segmented the US image systematically in order to define measurements of SAT and VAT using specifically pre-defined anatomical landmarks.

RESULTS

Intra-observer and inter-observer precision was assessed using Coefficient of Variation (CV). Measurements of SAT and total adipose for both observers were < 5% CV and < 10% CV for VAT in measures by both observers. Inter-observer reliability was assessed by Limits of Agreement (LoA). LoA were determined to be - 0.45 to 0.46 cm for SAT and - 0.34 to 0.53 cm for VAT values. Systematic bias of SAT measurement was 0.01 cm and 0.10 cm for VAT. Inter-observer precision was also assessed by coefficient of variation (CV: SAT, 3.1%; VAT, 7.2%; Total adipose, 3.0%).

CONCLUSION

Intra-observer precision was found to be acceptable for measures of SAT, VAT and total adipose according to anthropometric criterion, with higher precision reported in SAT values than in VAT. Inter-observer reliability assessed by Limits-Of-Agreement (LoA) confirm anthropometrically reliable to 0.5 cm. Systematic bias was minimal for both measures, falling within 95% confidence intervals. These results suggest that US can produce reliable, repeatable and accurate measures of SAT and VAT during pregnancy.

Involvement of Receptor for Advanced Glycation Endproducts in Hypertensive Disorders of Pregnancy

Preeclampsia/hypertensive disorders of pregnancy (PE/HDP) is a serious and potentially life-threatening disease. Recently, PE/HDP has been considered to cause adipose tissue inflammation, but the detailed mechanism remains unknown. We exposed human primary cultured adipocytes with serum from PE/HDP and healthy controls for 24 h, and analyzed mRNA expression of several adipokines, cytokines, and ligands of the receptor for advanced glycation endproducts (RAGE). We found that the mRNA levels of interleukin-6 (IL-6), C-C motif chemokine ligand 2 (CCL2), high mobility group box 1 (HMGB1), and RAGE were significantly increased by the addition of PE/HDP serum. Among RAGE ligands, advanced glycation endproducts (AGE) and HMGB1 increased mRNA levels of IL-6 and CCL2 in SW872 human adipocytes and mouse 3T3-L1 cells. The introduction of small interfering RNA for RAGE (siRAGE) into SW872 cells abolished the AGE- and HMGB1-induced up-regulation of IL-6 and CCL2. In addition, lipopolysaccharide (LPS), a ligand of RAGE, increased the expression of IL-6 and CCL2 and siRAGE attenuated the LPS-induced expression of IL-6 and CCL2. These results strongly suggest that the elevated AGE, HMGB1, and LPS in pregnant women up-regulate the expression of IL-6 and CCL2 via the RAGE system, leading to systemic inflammation such as PE/HDP.

Difference in Visceral Adipose Tissue in Pregnancy and Postpartum and Related Changes in Maternal Insulin Resistance

OBJECTIVE

To measure the difference between first-trimester and postpartum visceral adipose tissue (VAT), the agreement of this difference with change in body mass index, and whether a difference in VAT is associated with insulin resistance or glucose mishandling.

METHODS

Prospective study of 93 women with singleton pregnancies without a history of diabetes. Visceral adipose tissue depth was sonographically assessed at 11 to 14 weeks and at 6 to 12 weeks postpartum. Metabolic measures, sampled at 24 to 28 weeks and 6 to 12 weeks postpartum, included homeostatic model assessment of insulin resistance, insulin sensitivity index composite, and area under the 75-g oral glucose tolerance test curve.

RESULTS

First-trimester VAT depth explained only 37% (95% confidence interval [CI], 22-52) of the variation in postpartum VAT depth. There was limited agreement between the net change in postpartum minus first-trimester VAT depth and that same net change for body mass index (Cohen's kappa, 0.26; 95% CI, 0.05-0.47). Those with a net gain in VAT depth demonstrated poorer insulin sensitivity index postpartum than women with a net regression in VAT depth-a difference of -2.0 (95% CI, -3.3 to -0.69).

CONCLUSION

Sonographic assessment of postpartum VAT is feasible and may provide insight to metabolic changes between pregnancy and postpartum, beyond body mass index.

First-Trimester Abdominal Adipose Tissue Thickness to Predict Gestational Diabetes

OBJECTIVE

To estimate the discriminative capacity of first-trimester subcutaneous (SATT), visceral (VATT), and total (TATT) adipose tissue thickness in predicting gestational diabetes mellitus (GDM), including that requiring insulin.

METHODS

We prospectively recruited a cohort of 1048 nulliparous women. Ultrasound images were used to determine abdominal SATT, VATT, and TATT at 11 to 14 weeks' gestation. Multivariate logistic regression models were used to predict GDM, as well as insulin-requiring GDM. Model discrimination was expressed as area under the curve (AUC).

RESULTS

SATT (AUC 0.66, 95% CI 0.59-0.73), VATT (AUC 0.65, 95% CI 0.58-0.73), and TATT (AUC 0.68, 95% CI 0.61-0.76) were each associated with subsequent GDM. The respective AUC values for insulin-requiring GDM were 0.70 (95% CI 0.61-0.79), 0.73 (95% CI 0.65-0.82), and 0.76 (95% CI 0.67-0.84). At a false-positive rate of 10%, the detection rate for insulin-requiring GDM was 19% for maternal age ≥35 years, 31% for a BMI ≥31.6 kg/m², and 31% for TATT ≥61 mm, increasing to 42% in the model comprising all three measures.

CONCLUSION

First-trimester ultrasound measurement of adipose tissue is associated with a higher chance of developing GDM, especially insulin-requiring GDM.

Mesenteric visceral lipectomy using tissue liquefaction technology reverses insulin resistance and causes weight loss in baboons

BACKGROUND

Visceral obesity is associated with diabetogenic and atherogenic abnormalities, including insulin resistance and increased risk for cardiometabolic diseases and mortality. Rodent lipectomy studies have demonstrated a causal link between visceral fat and insulin resistance, yet human omentectomy studies have failed to replicate this metabolic benefit, perhaps owing to the inability to target the mesentery.

OBJECTIVES

We aimed to demonstrate that safe and effective removal of mesenteric fat could be achieved in obese insulin-resistant baboons using tissue liquefaction technology.

SETTING

Southwest National Primate Research Center, San Antonio, Texas.

METHODS

Tissue liquefaction technology has been developed to enable mesenteric visceral lipectomy (MVL) to be safely performed without disturbing the integrity of surrounding nerves and vessels in the mesentary. After an initial MVL optimization study (n = 3), we then performed MVL (n = 4) or sham surgery (n = 2) in a cohort of insulin-resistant baboons, and the metabolic phenotype was assessed via hyperinsulinemic-euglycemic clamps at baseline and 6 weeks later.

RESULTS

MVL led to a 75% improvement in glucose disposal at 6-weeks follow-up (P = .01). Moreover, despite removing only an average of 430 g of mesenteric fat (~1% of total body mass), MVL led to a 14.4% reduction in total weight (P = .001). Thus, these data demonstrate that mesenteric fat can be safely targeted for removal by tissue liquefaction technology in a nonhuman primate, leading to substantial metabolic improvements, including reversal of insulin resistance and weight loss.

CONCLUSIONS

These data provide the first demonstration of successful adipose tissue removal from the mesentery in a mammal. Importantly, we have demonstrated that when MVL is performed in obese, insulin-resistant baboons, insulin resistance is reversed, and significant weight loss occurs. Therefore, trials performing MVL in humans with abdominal obesity and related metabolic sequelae should be explored as a potential clinical tool to ameliorate insulin resistance and treat type 2 diabetes.

Visceral adipose tissue activated macrophage content and inflammatory adipokine secretion is higher in pre-eclampsia than in healthy pregnancys

Obesity increases pre-eclampsia (PE) risk. Adipose tissue inflammation may contribute to the clinical syndrome of PE. We compared adipose tissue macrophage infiltration and release of pro-inflammatory adipokines in PE and healthy pregnancy. Subcutaneous and visceral adipose tissue biopsies were collected from healthy (n=13) and PE (n=13) mothers. Basal and lipopolysaccharide (LPS) stimulated adipocyte TNFα, IL-6, CCL-2, and CRP release was measured. Adipose tissue cell densities of activated (cfms⁺) and total (CD68⁺) macrophages were determined. In PE only, visceral adipose tissue TNFα release was increased after LPS stimulation (57 [76] versus 81 [97] pg/ml/µg DNA, P=0.030). Basal TNFα release was negatively correlated insulin sensitivity of visceral adipocytes (r = −0.61, P=0.030) in PE. Visceral adipocyte IL-6 release was increased after LPS stimulation in PE only (566 [696] versus 852 [914] pg/ml/µg DNA, P=0.019). Visceral adipocyte CCL-2 basal (67 [61] versus 187 [219] pg/ml/µgDNA, P=0.049) and stimulated (46 [46] versus 224 [271] pg/ml/µg DNA, P=0.003) release was greater than in subcutaneous adipocytes in PE only. In PE, median TNF mRNA expression in visceral adipose tissue was higher than controls (1.94 [1.13–4.14] versus 0.8 [0.00–1.27] TNF/PPIA ratio, P=0.006). In visceral adipose tissue, CSF1R (a marker of activated macrophages) mRNA expression (24.8[11.0] versus 51.0[29.9] CSF1R/PPIA ratio, P=0.011) and activated (cfms+) macrophage count (6.7[2.6] versus 15.2[8.8] % cfms+/adipocyte, P=0.031) were higher in PE than in controls. In conclusion, our study demonstrates dysregulation of inflammatory pathways predominantly in visceral adipose tissue in PE. Inflammation of visceral adipose tissue may mediate many of the adverse metabolic effects associated with PE.

Hepatic fat and abdominal adiposity in early pregnancy together predict impaired glucose homeostasis in mid-pregnancy

Hepatic fat and abdominal adiposity individually reflect insulin resistance, but their combined effect on glucose homeostasis in mid-pregnancy is unknown. A cohort of 476 pregnant women prospectively underwent sonographic assessment of hepatic fat and visceral (VAT) and total (TAT) adipose tissue at 11–14 weeks' gestation. Logistic regression was used to assess the relation between the presence of maternal hepatic fat and/or the upper quartile (Q) of either VAT or TAT and the odds of developing the composite outcome of impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or gestational diabetes mellitus at 24–28 weeks' gestation, based on a 75 g OGTT. Upon adjusting for maternal age, ethnicity, family history of DM and body mass index (BMI), the co-presence of hepatic fat and quartile 4 (Q4) of VAT (adjusted odds ratio (aOR) 6.5, 95% CI: 2.3–18.5) or hepatic fat and Q4 of TAT (aOR 7.8 95% CI 2.8–21.7) were each associated with the composite outcome, relative to women with neither sonographic feature. First-trimester sonographic evidence of maternal hepatic fat and abdominal adiposity may independently predict the development of impaired glucose homeostasis and GDM in mid-pregnancy.

First-Trimester Maternal Abdominal Adiposity Predicts Dysglycemia and Gestational Diabetes Mellitus in Midpregnancy

OBJECTIVE

This study assessed the association between first-trimester abdominal adiposity and dysglycemia and gestational diabetes mellitus (GDM) in midpregnancy.

RESEARCH DESIGN AND METHODS

In a prospective cohort of 485 women, we measured subcutaneous (SAT), visceral (VAT), and total (TAT) adipose tissue depth, using ultrasound at 11-14 weeks' gestation. Logistic regression analysis assessed the relation between quartiles of SAT, VAT, or TAT depth and the composite outcome of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or GDM, based on a 75-g oral glucose tolerance test at 24-28 weeks.

RESULTS

Adjusting for maternal age, ethnicity, family history of diabetes, and BMI, quartile 4 versus quartile 1 VAT (adjusted odds ratio [aOR] 3.1, 95% CI 1.1-9.5) and TAT (aOR 2.7, 95% CI 1.1-7.8) were significantly associated with the composite outcome, but SAT was not (aOR 1.8, 95% CI 0.70-4.8). The same was seen for GDM alone.

CONCLUSIONS

Elevated first-trimester VAT and TAT depth independently predicted the risk of dysglycemia later in pregnancy.