Omental Research Articles

Plasma adiponectin/leptin ratio associates with subcutaneous abdominal and omental adipose tissue characteristics in women

BackgroundA better understanding of adipose tissue (AT) dysfunction, which includes morphological and functional changes such as adipocyte hypertrophy as well as impaired adipogenesis, lipid storage/mobilization, endocrine and inflammatory responses, is needed in the context of obesity. One dimension of AT dysfunction, secretory adiposopathy, often assessed as a low plasma adiponectin (A)/leptin (L) ratio, is commonly observed in obesity. The aim of this study was to examine markers of AT development and metabolism in 67 women of varying age and adiposity (age: 40-62 years; body mass index, BMI: 17-41 kg/m2) according to levels of adiponectinemia, leptinemia or the plasma A/L ratio.MethodsBody composition, regional AT distribution and circulating adipokines were determined. Lipolysis was measured from glycerol release in subcutaneous abdominal (SCABD) and omental (OME) adipocytes under basal, isoproterenol-, forskolin (FSK)- and dibutyryl-cyclic AMP (DcAMP)-stimulated conditions. Adipogenesis (C/EBP-α/β/δ, PPAR-γ2 and SREBP-1c) and lipid metabolism (β2-ARs, HSL, FABP4, LPL and GLUT4) gene expression (RT-qPCR) was assessed in both fat depots. Participants in the upper versus lower tertile of adiponectin, leptin or the A/L ratio were compared.ResultsBasal lipolysis was similar between groups. Women with a low plasma A/L ratio were characterized by higher adiposity and larger SCABD and OME adipocytes (p<0.01) compared to those with a high ratio. In OME adipocytes, women in the low adiponectinemia tertile showed higher isoproterenol-stimulated lipolysis (0.01<p<0.05), while those in the high leptinemia tertile displayed increased lipolytic response to this agent (p<0.05). However, lipolysis stimulated by isoproterenol was enhanced in both compartments (0.01<p<0.05) in women with a low plasma A/L ratio. AT abundance of selected transcripts related to adipogenesis or lipid metabolism did not differ between women with or without secretory adiposopathy, except for lower GLUT4 mRNA levels in OME fat.ConclusionsSecretory adiposopathy assessed as the plasma A/L ratio, more so than adiponectin or leptin levels alone, discriminates low and elevated lipolysis in OME and SCABD adipocytes despite similar AT expression of selected genes involved in lipid metabolism.

17β-hydroxysteroid dehydrogenase type 2 activity, expressionand cellular localization in abdominal adipose tissues from women.

17β-hydroxysteroid dehydrogenase type 2 (17β-HSD2) may be involved in the local modulation of estradiol (E2) availability in adipose tissues. To assess the conversion of E2 into estrone (E1) as well as the expression of 17β-HSD2 and its localization in omental (OM) and subcutaneous (SC) adipose tissues obtained from women. Rates of 14 C-E1 formation from 14 C-E2 were measured in OM and SC adipose tissue homogenates from 29 women. Specific 17β-HSD2 inhibitor EM-919 was tested in OM and SC adipose tissue homogenates (n = 6). 17β-HSD2 mRNA expression was measured in whole OM and SC adipose tissues (n = 14). Cellular localization of the enzyme was examined using immunohistochemistry. Anthropometric measurements were obtained and body composition as well as body fat distribution were measured. Significant 14 C-E1 formation from 14 C-E2 in OM and SC tissue homogenates was detected. The rate of 14 C-E1 formation was significantly higher in OM than SC adipose tissue (p < .0001). The conversion of 14 C-E2 to 14 C-E1 was significantly inhibited by EM-919 in OM (p < .05) and SC (p < .05) adipose tissues. Significantly higher expression of 17β-HSD2 mRNA in OM versus SC fat was found (p = .03). 17β-HSD2 was localized in the vasculature of OM and SC tissues. Significant negative associations were detected between OM 17β-HSD2 activity and body mass index, WC, lean body mass as well as SC adipose tissue areas. 17β-HSD2 converts E2 to E1 in OM and SC adipose tissues of women. The activity of this enzyme decreases with increasing adiposity.

Contribution of markers of adiposopathy and adipose cell size in predicting insulin resistance in women of varying age and adiposity

ABSTRACT Adipose tissue (AT) dysfunctions, such as adipocyte hypertrophy, macrophage infiltration and secretory adiposopathy (low plasma adiponectin/leptin, A/L, ratio), associate with metabolic disorders. However, no study has compared the relative contribution of these markers to cardiometabolic risk in women of varying age and adiposity. Body composition, regional AT distribution, lipid-lipoprotein profile, glucose homeostasis and plasma A and L levels were determined in 67 women (age: 40-62 years; BMI: 17-41 kg/m2). Expression of macrophage infiltration marker CD68 and adipocyte size were measured from subcutaneous abdominal (SCABD) and omental (OME) fat. AT dysfunction markers correlated with most lipid-lipoprotein levels. The A/L ratio was negatively associated with fasting insulinemia and HOMA-IR, while SCABD or OME adipocyte size and SCABD CD68 expression were positively related to these variables. Combination of tertiles of largest adipocyte size and lowest A/L ratio showed the highest HOMA-IR. Multiple regression analyses including these markers and TAG levels revealed that the A/L ratio was the only predictor of fasting insulinemia and HOMA-IR. The contribution of the A/L ratio was superseded by adipose cell size in the model where the latter replaced TAGs. Finally, leptinemia was a better predictor of IR than adipocyte size and the A/L ratio in our participants sample.

Function and composition of pancreatic islet cell implants in omentum of type 1 diabetes patients

Intraportal (IP) islet cell transplants can restore metabolic control in type 1 diabetes patients, but limitations raise the need for establishing a functional beta cell mass (FBM) in a confined extrahepatic site. This study reports on function and composition of omental (OM) implants after placement of islet cell grafts with similar beta cell mass as in our IP-protocol (2–5.106 beta cells/kg body weight) on a scaffold. Four of seven C-peptide-negative recipients achieved low beta cell function (hyperglycemic clamp [HGC] 2–8 percent of controls) until laparoscopy, 2–6 months later, for OM-biopsy and concomitant IP-transplant with similar beta cell dose. This IP-transplant increased HGC-values to 15–40 percent. OM-biopsies reflected the composition of initial grafts, exhibiting varying proportions of endocrine-cell-enriched clusters with more beta than alpha cells and leucocyte pole, non-endocrine cytokeratin-positive clusters surrounded by leucocytes, and scaffold remnants with foreign body reaction. OM-implants on a polyglactin-thrombin-fibrinogen-scaffold presented larger endocrine clusters with infiltrating endothelial cells and corresponded to the higher HGC-values. No activation of cellular immunity to GAD/IA2 was measured post-OM-transplant. Establishment of a metabolically adequate FBM in omentum may require a higher beta cell number in grafts but also elimination of their immunogenic non-endocrine components as well as local conditioning that favors endocrine cell engraftment and function.

Intra-abdominal adipose depot variation in adipogenesis, lipogenesis, angiogenesis, and fibrosis gene expression and relationships with insulin resistance and inflammation in premenopausal women with severe obesity.

Although severe obesity is associated with insulin resistance (IR) and inflammation, secretory function of intra-abdominal adipose tissues and their relationships with IR and inflammation markers remain poorly understood. Aims were to measure gene expression of adipogenic (C/EBPα/β, PPARγ-1/2, SREBP-1c, LXRα), lipogenic (SCD1, DGAT-1/2), angiogenic (VEGFα, leptin), and fibrotic (LOX, COL6A3) factors in the round ligament (RL), omental (OM), and mesenteric (ME) fat depots and to evaluate their relationships with IR and inflammation markers in 48 women with severe obesity undergoing bariatric surgery. Gene expression was assessed by RT-qPCR, and plasma glucose and insulin (HOMA-IR calculated), PAI-1, IL-6, TNFα, adiponectin, and leptin levels were determined. C/EBPβ and PPARγ-1/2 mRNA levels were more expressed in the OM (0.001<p<0.05). ME showed the highest expression of C/EBPα, SREBP-1c, DGAT-2, and leptin and the lowest of SCD1, LXRα, VEGFα, and LOX (0.001<p<0.05). COL6A3 expression was higher in the ME and RL (p<0.001). COL6A3 expression was negatively associated with IR indices in the RL (0.01<p<0.05) and with fasting glycemia and HOMA-IR in the OM (0.001<p<0.05). VEGFα expression was positively related to TNFα and PAI-1 in the RL (0.001<p<0.05) and to PAI-1 in the OM (p<0.05) and negatively to PAI-1 in the ME (p<0.001). Fibrosis gene expression correlated negatively with inflammation in RL and OM (0.001<p<0.05) and positively with PAI-1 in the ME (0.001<p<0.05). The varying relationships of gene expression profiles with selected IR indices and inflammation biomarkers further suggest these fat depots have distinct contributions to overall health in premenopausal women with severe obesity.

Characterization and differentiation potential of mesenchymal stem cells isolated from multiple canine adipose tissue sources

BackgroundMesenchymal stem cells (MSCs) are undifferentiated cells that can give rise to a mesoderm lineage. Adipose-derived MSCs are an easy and accessible source for MSCs isolation, although each source of MSC has its own advantages and disadvantages. Our study identifies a promising source for the isolation and differentiation of canines MSCs. For this purpose, adipose tissue from inguinal subcutaneous (SC), perirenal (PR), omental (OM), and infrapatellar fat pad (IPFP) was isolated and processed for MSCs isolation. In the third passage, MSCs proliferation/metabolism, surface markers expression, in vitro differentiation potential and quantitative reverse transcription PCR (CD73, CD90, CD105, PPARγ, FabP4, FAS, SP7, Osteopontin, and Osteocalcin) were evaluated.ResultsOur results showed that MSCs derived from IPFP have a higher proliferation rate, while OM-derived MSCs have higher cell metabolism. In addition, MSCs from all adipose tissue sources showed positive expression of CD73 (NT5E), CD90 (THY1), CD105 (ENDOGLIN), and very low expression of CD45. The isolated canine MSCs were successfully differentiated into adipogenic and osteogenic lineages. The oil-red-O quantification and adipogenic gene expression (FAS, FabP4, and PPARγ) were higher in OM-derived cells, followed by IPFP-MSCs. Similarly, in osteogenic differentiation, alkaline phosphatase activity and osteogenic gene (SP7 and Osteocalcin) expression were higher in OM-derived MSCs, while osteopontin expression was higher in PR-derived MSCs.ConclusionIn summary, among all four adipose tissue sources, OM-derived MSCs have better differentiation potential toward adipo- and osteogenic lineages, followed by IPFP-MSCs. Interestingly, among all adipose tissue sources, MSCs derived from IPFP have the maximum proliferation potential. The characterization and differentiation potential of canine MSCs isolated from four different adipose tissue sources are useful to assess their potential for application in regenerative medicine.

Impaired mRNA splicing and proteostasis in preadipocytes in obesity-related metabolic disease.

Preadipocytes are crucial for healthy adipose tissue expansion. Preadipocyte differentiation is altered in obese individuals, which has been proposed to contribute to obesity-associated metabolic disturbances. Here, we aimed at identifying the pathogenic processes underlying impaired adipocyte differentiation in obese individuals with insulin resistance (IR)/type 2 diabetes (T2D). We report that down-regulation of a key member of the major spliceosome, PRFP8/PRP8, as observed in IR/T2D preadipocytes from subcutaneous (SC) fat, prevented adipogenesis by altering both the expression and splicing patterns of adipogenic transcription factors and lipid droplet-related proteins, while adipocyte differentiation was restored upon recovery of PRFP8/PRP8 normal levels. Adipocyte differentiation was also compromised under conditions of endoplasmic reticulum (ER)-associated protein degradation (ERAD) hyperactivation, as occurs in SC and omental (OM) preadipocytes in IR/T2D obesity. Thus, targeting mRNA splicing and ER proteostasis in preadipocytes could improve adipose tissue function and thus contribute to metabolic health in obese individuals.

Clinical and Surgical Outcomes in Extensive Scalp Reconstruction after Oncologic Resection: A Comparison of Anterolateral Thigh, Latissimus Dorsi and Omental Free Flaps.

Microsurgical scalp reconstruction is indicated in patients with large scalp defects. The aim of this study was to compare the outcomes of scalp reconstruction in oncologic patients reconstructed with latissimus dorsi (LD), anterolateral thigh (ALT), and omental (OM) free flaps. Thirty oncologic patients underwent scalp reconstruction with LD (10), ALT (11), and OM (9) flaps. The length of the vascular pedicle, the operation time, the possibility of a two-team approach, the length of hospital stays, the complications, and the aesthetic results were evaluated. The OM flap was the flap with the shortest vascular pedicle length with a mean of 6.26 ± 0.16 cm, compared to the LD flap, which was 12.34 ± 0.55 cm and the ALT flap with 13.20 ± 0.26 cm (p < 0.05). The average time of surgery was 6.6 ± 0.14 h in patients reconstructed with OM, compared to the LD flap, which was 8.91 ± 0.32 h and the ALT flap with 7.53 ± 0.22 h (p < 0.05). A two-team approach was performed in all patients for OM flaps and ALT flaps, but only in two patients reconstructed with the LD flap (p < 0.001). In patients reconstructed with the OM flap, a very satisfactory or satisfactory result was reported in seven patients (77.8%). Eight patients reported a very unsatisfactory or unsatisfactory result with LD flap (80%) and 10 patients with ALT flap (90.9%) (p = 0.002). The mean hospital stay after surgery was not statistically significant (p > 0.05). As for complications, two patients reconstructed with OM flap, five LT flaps, and two ALT flaps developed complications, not statistically significant (p = 0.235). Omental flap, latissimus dorsi flap, and anterolateral thigh flap fulfill most of the characteristics for complex scalp reconstruction. The decision on which flap to use should be based on clinical aspects of the patients taking into account that the three flaps show similar rates of complications and length of hospital stay. Regarding the aesthetic outcome, OM flap or LD flap should be considered for reconstruction of extensive scalp defects.

Pre- and Post-Slaughter Methodologies to Estimate Body Fat Reserves in Lactating Saanen Goats.

Simple SummaryIn this study, we present the results of a trial on which we compared pre- and post-slaughter methodologies to estimate body fat reserves in dairy goats. Our results evidenced that fat thickness measured with ultrasound in the perirenal region was the best pre-slaughter measurement for estimating fat reserves in lactating Saanen goats, whereas empty body weight and hot carcass weight were the best post-slaughter predictors for estimating fat reserves. Body condition score could be a useful tool, but it seems that it needs to be re-evaluated to predict adequately fat depots in lactating Saanen goats.This work aimed to compare pre- and post-slaughter methodologies to estimate body fat reserves in dairy goats. Twenty-six lactating Saanen goats ranging from 43.6 to 69.4 kg of body weight (BW) and from 1.84 to 2.96 of body condition score (BCS; 0–5 range) were used. Fifteen pre-slaughter and four post-slaughter measurement values were used to estimate the weight of fat in the omental (OM), mesenteric (MES), perirenal (PR), organ (ORG), carcass (CARC), and non-carcass components (NC) and total (TOT, calculated as the sum of CARC and NC) depots in goats. The pre-slaughter measurements were withers height; rump height; rump length; pelvis width; chest depth; shoulder width; heart girth; body length; sternum height; BW; BCS assessed in the lumbar (BCSl) and sternal (BCSs) regions; and fat thickness measured by ultrasound in the lumbar (FTUSl), sternal (FTUSs), and perirenal (FTUSpr) regions. The post-slaughter measurements were hot carcass weight (HCW), empty body weight (EBW), and fat thickness measured by digital caliper in the lumbar (FTDCl) and sternal (FTDCs) regions. Linear and multiple regressions were fit to data collected. BW, BCS (from lumbar and sternal regions), all somatic measurements, and fat thickness measured by ultrasound in the lumbar and sternal regions were not adequate to estimate the weight of total fat in lactating Saanen goats (R2 ≤ 0.55). The best pre-slaughter and post-slaughter estimators of OM, MES, PR, ORG, NC, and TOT fat were FTUSpr and EBW, respectively. Among pre- and post-slaughter measurements, BCSl (R2 = 0.63) and HCW (R2 = 0.82) provided the most accurate predictions of CARC fat, respectively. Multiple regression using the pre-slaughter variables FTUSpr, BW, and BCSl yielded estimates of TOT fat with an R2 = 0.92 (RSD = 1.14 kg). On the other hand, TOT fat predicted using the post-slaughter variables HCW and FTDCs had an R2 = 0.83 (RSD = 1.41 kg). These results confirm that fat reserves can be predicted in lactating Saanen goats with high precision using multiple regression equations combining in vivo measurements.

Phosphoproteomic Analysis of Subcutaneous and Omental Adipose Tissue Reveals Increased Lipid Turnover in Dairy Cows Supplemented with Conjugated Linoleic Acid.

Phosphoproteomics is a cutting-edge technique that can be utilized to explore adipose tissue (AT) metabolism by quantifying the repertoire of phospho-peptides (PP) in AT. Dairy cows were supplemented with conjugated linoleic acid (CLA, n = 5) or a control diet (CON, n = 5) from 63 d prepartum to 63 d postpartum; cows were slaughtered at 63 d postpartum and AT was collected. We performed a quantitative phosphoproteomics analysis of subcutaneous (SC) and omental (OM) AT using nanoUPLC-MS/MS and examined the effects of CLA supplementation on the change in the phosphoproteome. A total of 5919 PP were detected in AT, and the abundance of 854 (14.4%) were differential between CON and CLA AT (p ≤ 0.05 and fold change ± 1.5). The abundance of 470 PP (7.9%) differed between OM and SC AT, and the interaction treatment vs. AT depot was significant for 205 PP (3.5% of total PP). The integrated phosphoproteome demonstrated the up- and downregulation of PP from proteins related to lipolysis and lipogenesis, and phosphorylation events in multiple pathways, including the regulation of lipolysis in adipocytes, mTOR signaling, insulin signaling, AMPK signaling, and glycolysis. The differential regulation of phosphosite on a serine residue (S777) of fatty acid synthase (FASN) in AT of CLA-supplemented cows was related to lipogenesis and with more phosphorylation sites compared to acetyl-coenzyme A synthetase (ACSS2). Increased protein phosphorylation was seen in acetyl-CoA carboxylase 1 (ACACA;8 PP), FASN (9 PP), hormone sensitive lipase (LIPE;6 PP), perilipin (PLIN;3 PP), and diacylglycerol lipase alpha (DAGLA;1 PP) in CLA vs. CON AT. The relative gene expression in the SC and OM AT revealed an increase in LIPE and FASN in CLA compared to CON AT. In addition, the expression of DAGLA, which is a lipid metabolism enzyme related to the endocannabinoid system, was 1.6-fold higher in CLA vs. CON AT, and the expression of the cannabinoid receptor CNR1 was reduced in CLA vs. CON AT. Immunoblots of SC and OM AT showed an increased abundance of FASN and a lower abundance of CB1 in CLA vs. CON. This study presents a complete map of the SC and the OM AT phosphoproteome in dairy cows following CLA supplementation and discloses many unknown phosphorylation sites, suggestive of increased lipid turnover in AT, for further functional investigation.

Suppression of GATA-3 increases adipogenesis, reduces inflammation and improves insulin sensitivity in 3T3L-1 preadipocytes

Impaired adipogenesis plays an important role in the development of obesity-associated insulin resistance and type 2 diabetes. Adipose tissue inflammation is a crucial mediator of this process. GATA-3 plays important roles in adipogenesis and inflammation. The aim of this study is to investigate the impact of GATA-3 suppression on improving adipogenesis, lowering inflammation and reversing insulin resistance. GATA-3 levels were measured in subcutaneous (SC) and omental (OM) adipose tissues obtained from insulin sensitive (IS) and insulin resistant (IR) obese individuals during weight reduction surgeries. The effect of GATA-3 suppression on adipogenesis, expression of inflammatory cytokines and insulin resistance biomarkers was performed in 3T3L-1 mouse preadipocytes via transfection with GATA-3-specific DNAzyme. GATA-3 expression was higher in OM compared to SC adipose tissues and in stromal vascular fraction-derived differentiating preadipocytes from IR obese individuals compared to their IS counterparts. Suppression of GATA-3 expression in 3T3L-1 mouse preadipocytes with GATA-3 specific inhibitor reversed 4-hydroxynonenal-induced impaired adipogenesis and triggered changes in the expression of insulin signaling-related genes. GATA-3 inhibition also modulated the expression of IL-6 and IL-10 and lowered the expression of insulin resistance biomarkers (PAI-1 and resistin) and insulin resistance phosphoproteins (p-BAD, p-PTEN and p-GSK3β). Inhibiting GATA-3 improves adipocytes differentiation, modulates the secretion of inflammatory cytokines and improves insulin sensitivity in insulin resistant cells. Suppression of GATA-3 could be a promising tool to improve adipogenesis, restore insulin sensitivity and lower obesity-associated inflammation in insulin resistant individuals.

Age, Sex, and Depot-Specific Differences in Adipose-Tissue Estrogen Receptors in Individuals with Obesity.

The aim of this study was to examine the effects of sex and menopausal status on depot-specific estrogen signaling in white adipose tissue (AT) in age-matched men and women with morbid obesity. A total of 28 premenopausal women, 16 postmenopausal women, and 27 age-matched men undergoing bariatric surgery were compared for omental (OM) AT (OMAT) and abdominal subcutaneous (SQ) AT (SQAT) genes and proteins. With the exception of fasting nonesterified fatty acids being higher in women (P < 0.01), no differences were found in other indicators of glucose and lipid metabolism. In OMAT, estrogen receptor (ER) beta (ERβ) levels were higher in older women than in younger women and older men (sex-age interaction, P < 0.01), and aromatase expression was higher in older men than in older women (P < 0.05). In SQAT, women had lower expression of ERβ than men (P < 0.05). Protein content of ER alpha and ERβ was highly correlated with the mitochondrial protein uncoupling protein 1 across sexes and ages (P < 0.001). Age increased SQ inflammatory gene expression in both sexes. In morbid obesity, sex and age affect AT ERs, lipid metabolism, mitochondrial uncoupling protein 1, and inflammatory expression in an AT depot-dependent manner. The SQAT immunometabolic profile is heavily influenced by age and menopause status, more so than OMAT.

Adipose tissue depot-specific intracellular and extracellular cues contributing to insulin resistance in obese individuals.

Adipose tissue dysregulation in obesity strongly influences systemic metabolic homeostasis and is often linked to insulin resistance (IR). However, the molecular mechanisms underlying adipose tissue dysfunction in obesity are not fully understood. Herein, a proteomic analysis of subcutaneous (SC) and omental (OM) fat from lean subjects and obese individuals with different degrees of insulin sensitivity was performed to identify adipose tissue biomarkers related to obesity‐associated metabolic disease. Our results suggest that dysregulation of both adipose tissue extracellular matrix (ECM) organization and intracellular trafficking processes may be associated with IR in obesity. Thus, abnormal accumulation of the small leucine‐rich proteoglycan, lumican, as observed in SC fat of IR obese individuals, modifies collagen I organization, impairs adipogenesis and activates stress processes [endoplasmic reticulum and oxidative stress] in adipocytes. In OM fat, IR is associated with increased levels of the negative regulator of the Rab family of small GTPases, GDI2, which alters lipid storage in adipocytes by inhibiting insulin‐stimulated binding of the Rab protein, Rab18, to lipid droplets. Together, these results indicate that lumican and GDI2 might play depot‐dependent, pathogenic roles in obesity‐associated IR. Our findings provide novel insights into the differential maladaptive responses of SC and OM adipose tissue linking obesity to IR.

Differences in Neuregulin 4 Expression in Children: Effects of Fat Depots and Obese Status

ABSTRACT Purpose To observe the expression of Nrg4, uncoupling protein-1 (UCP1), tumor necrosis factor α (TNFα), CD31, VE-cadherin/CDH5 and vascular endothelial growth factor A (VEGF-A) mRNA in abdominal subcutaneous (SC), omental (OM) adipose tissue in children with relation to anthropometric parameters. Further to verify the effect of inflammatory mediators on Nrg4 and UCP1 mRNA expression in adipocytes. Methods Paired SC and OM adipose tissues were obtained from 58 children. In vitro, the adipocytes isolated from primary inguinal adipose tissue of mice were treated with TNFα (50 ng/ml) for 12–48 h. mRNA levels of Nrg4, UCP1 and TNFα were determined by real-time PCR. Results Nrg4, UCP1, VEGF-A and CDH5 mRNA levels in SC were significantly higher than those in OM adipose tissue and the mRNA level of TNFα showed the opposite result. Moreover, Nrg4 and UCP1 mRNA in SC were significantly lower in overweight children compared to normal weight children. Nrg4 in SC and OM was negatively associated with BMISDS, WHtR. CDH55 mRNA in OM was negatively associated with WHR. VEGF-A was positively correlated with Nrg4 in SC. In vitro, Nrg4 and UCP1 mRNA levels in adipocytes were dose- and time-dependently decreased under TNFα treatment. Conclusions Nrg4, UCP1, VEGF-A and CDH5 mRNA expression in adipose tissues display a depot-specific pattern. Nrg4 mRNA levels in adipose tissue are decreased with obesity and associated with WAT browning and angiogenesis. TNFα may be involved in the regulation of Nrg4 level in adipose tissue, which may be one of the causes of the down-regulation of Nrg4 expression in obesity with chronic inflammatory response.

Developing equations for predicting internal body fat in Pelibuey sheep using ultrasound measurements

Abstract The objective of the present study was to to develop equations for predicting internal body fat in Pelibuey sheep using ultrasound measurements (USM). Twenty-four hours before slaughter, USM were obtained for 35 male fattening Pelibuey sheep with a bodyweight (BW) of 39.22 ± 7.01 kg. The back-fat thickness (cm) and longissimus thoracis and lumborum muscle area (cm2) were measured between the 12th and 13th thoracic vertebrae (TFT and TLDA) and the 3rd and 4th lumbar vertebrae (LFT and LLDA). Additionally, ultrasound kidney-fat thickness (uKFT) was measured behind the 13th right rib. After slaughter, data on both carcass and non-carcass components were recorded. Internal fat (IF, internal adipose tissue) was dissected, weighed and grouped as mesenteric (MF), omental (OM) or kidney and perirenal fat (PRF). Correlation coefficients among variables were calculated, and regressions were carried out according to SAS procedures. Only the LLDA was poorly correlated (r = 0.38, P 0.05). The uKFT was highly related with internal body fat depots (0.78 ≤ r ≤ 0.91, P 0.69 ≤ and ≤ 0.83), high accuracy (bias correction factor > 0.93) and good reproducibility index (concordance correlation coefficient > 0.81 and ≤ 0.90) along with a moderate to high efficiency of prediction (from 0.71 to 0.82). In conclusion, our results indicated that the use of ultrasound measurements could accurately and precisely be used as alternatives to predict the internal fat depots of Pelibuey sheep.

2094-P: Decreased Human Adipose Tissue-Resident Eosinophils in Obese Subjects Is Associated with Increased Insulin Resistance

Eosinophils (EOS) have been shown to play a major role in animal adipose tissue (AT) metabolism by promoting insulin sensitivity (IS) through an increase in alternatively activated macrophages (M2). Additionally, AT EOS are known to be decreased in obese mice. Currently, translational evidence is lacking for the role of EOS in human AT metabolism and IS. We investigated whether human AT-resident EOS numbers, as in animal models, are decreased in obese subjects and correlate with their degree of insulin resistance (IR). To date, we have studied 16 lean subjects (F15/M1, age 43 +2 years old; BMI 22.5+0.4kg/m2; HOMA-IR: 0.99 +0.38) and 22 obese, IR subjects (17F/5M, age 42 +1.3 years old; BMI: 38.9 +1.0kg/m2; HOMA-IR:5.0 +1.6) undergoing elective laparoscopic surgery. During surgical procedure, subcutaneous (SC) and omental (OM) fat was harvested. Stromal vascular fraction (SVF) was isolated after collagenase digestion of the fat samples. SVF was subjected to FACS analysis using BD Biosciences FACSAria III Cell Sorter with EOS count normalized as percent of CD45+ cells. Viable EOS were isolated and cytospin preparation was stained with a Diff-Quik. EOS isolated from SC AT of lean(L) subjects were found to significantly outnumber those obtained from obese (Ob) subjects by a 2.1:1 ratio (SC L:2.34 +0.29 vs. SC Ob: 1.11 +0.21, P&amp;lt;0.03). A similar, but non-significant, trend was observed in OM. Furthermore, the number of SC AT-EOS was significantly inversely correlated with BMI, % fat and QUICKI index. qPCR analysis of SC AT mRNA revealed significantly increased classically activated macrophage markers (M1) (IL-1, IL-6, TNFα) in Ob vs. L, respectively while M2 markers (ARG-1, CCL24, CCL26) were significantly decreased in Ob vs. L. Based on these results we propose that, as in animal models, AT-resident EOS mediate AT metabolism and potentially IS by preserving an anti-inflammatory milieu within lean AT. Further studies are needed to elucidate the mechanism(s) involved. Disclosure J.D. Hernandez: None. T. Li: None. C. Rau: None. M.Y. Masuda: None. J.A. Madura: None. E.A. Jacobsen: None. E. DeFilippis: None. Funding Arizona Department of Health Services (14-00003606); Arizona Biomedical Research Commission; Kathryn H. and Roger Penske Career Development Award

The effects of ambient particulate matter on human adipose tissue

ABSTRACTThe effects of particulate matter (PM) air pollution on adipose tissue have mainly been studied in animal models. The aim of this study was to examine the potential associations between PM exposure and 25 cellular markers in human omental (OM) and subcutaneous (SC) adipose tissue. The PM exposure assessments for both PM2.5 (PM <2.5 μm in diameter) and PM10 (<10 μm) were based upon a novel hybrid satellite-based spatio-temporally resolved model. We calculated the PM exposure above the background threshold for 1 week (acute phase), 3 and 6 months (intermediate phase), and 1 year (chronic phase) prior to tissue harvesting and tested the associations with adipose cell metabolic effects using multiple linear regressions and heat maps strategy. Chemokine levels were found to increase after acute and intermediate exposure duration to PM10. The levels of stress signaling biomarkers in the SC and OM tissues rose after acute exposure to PM10 and PM2.5. Macrophage and leucocyte counts were associated with severity of PM exposure in all three duration groups. Adipocyte diameter decreased in all exposure periods. Our results provide evidence for significant contribution of air pollutants exposure to adipose tissue inflammation as well as for pathophysiological mechanisms of metabolic dysregulation that may be involved in the observed responses.

Age, Sex, and Depot Differences in Adipose Tissue from Obese Subjects

PurposeAdipose tissue (AT) distribution and metabolism are largely affected by the sex hormone, estrogen (E2), presumably through E2 receptors (ER) a and b. In both males and females, E2 biosynthesis in AT occurs through aromatase enzyme, which is responsible for converting androstenedione to estrone. Menopause, loss of ovarian E2, associates with an abrupt increase in metabolic disease risk for reasons that are not fully understood, implicating E2 signaling within AT as playing a role in metabolic health. The purpose of this study was to determine the individual and combined effects of menopause and age on AT depot‐specific immunometabolic characteristics, in morbidly obese, age matched, men and women.Methods34 women (20 Pre‐menopausal (PRE), 14 Post‐menopausal (POST)) and 27 age‐matched men (M) (14 M‐PRE, 13 M‐POST) undergoing bariatric surgery consented to collection of omental (OM) AT; 26 of which consented to collection of abdominal subcutaneous (SQ) AT. Blood samples were collected prior to surgery. AT samples were immediately processed for histological, gene, and protein analyses.Statistics2‐way ANOVA for age group (A), sex (S), and A*S interactions were performed; p&lt;0.05 was considered significant.ResultsBlood glucose, cholesterol, triglycerides, and HDL‐c were similar between groups; whereas, free fatty acids were significantly higher in females than males (1.07±0.04 vs. 0.95±0.05 mmol/L, respectively, p=0.049). OMAT cell size was larger in males than females (6382.0±521.1 vs. 4610.4±521.1 mm2, respectively, p=0.028); SQAT cell size was not different by S or A. SQAT gene expression (but not protein content) of ERb was significantly higher in females than males (1.21±0.22 vs. 0.60 ± 0.12, p=0.049). ERa gene expression was similar between A and S in OM and SQAT but there was a trend toward A*S interaction (p=0.052) in ERa protein in OMAT such that POST &gt; than PRE, M‐PRE, and M‐POST, all p values &lt;0.01. There was an A*S interaction for OMAT gene expression of aromatase (p=0.014); M‐Post &gt; POST (p=0.023) and M‐POST &gt; M‐PRE (p=0.044). The older age group had increased expression of SQAT TNFa (p=0.009). In SQAT, an A*S interaction (p=0.025) occurred in NFkB protein content, such that PRE &lt; POST (p=0.092) and PRE &lt; M‐PRE (p=0.076). Mitochondrial protein of electron transport chain (ETC) complexes (C) in SQAT had significant A*S interactions for C 2 and 3 (p=0.040 and 0.027, respectively). Post hoc differences in SQAT C2 PRE &lt; POST (p=0.043) and C3 POST &gt; PRE (p=0.060) and POST &gt; M‐POST (p=0.065). C1 tended to follow similar patterns between A and S as C 2 and 3, A*S interaction p=0.055. OMAT ETC protein content was similar between A and S. An A*S trend (p=0.063) in SQ UCP1 content was observed such that POST &gt; PRE (p=0.051) and POST &gt; M‐POST (p=0.062); OMAT UCP1 was similar by A and S.ConclusionIn morbid obesity, loss of E2 and aging may differentially affect OMAT E2 signaling pathways in men and women. Conversely, loss of E2 and aging affect SQAT mitochondrial and inflammatory pathways.Support or Funding InformationResearch supported by Dr. Kanaley RO1DK101513This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

OP-32 - 4-Hydroxynonenal as a biomarker of redox regulation in pathophysiology of metabolic stress

While pathophysiology of metabolic stress has yet to be revealed, it seems that obesity-associated ectopic fat deposition and increased risk of insulin resistance can result from impaired fat accumulation associated with oxidative stress in the adipose tissue. Therefore, our recent studies analyzed potential roles of 4-hydroxynonenal (HNE) on adipogenesis in respect to effects of metformin and insulin. The presence of HNE-protein adducts was assessed in subcutaneous (SC) and omental (OM) adipose tissues obtained from obese individuals along with its endogenous accumulation in proliferating and differentiating preadipocytes derived from these tissues, while the impact of HNE on preadipocyte redox homeostasis, proliferation, adipogenic capacity and signaling pathways were determined in vitro. Majority of HNE-protein adducts accumulated in adipocytes and blood vessels, while exposure of preadipocytes to HNE inhibited their growth increasig H2O2, CAT, PRX2, TRX1, SOD1 and SOD2. The HNE also up-regulated anti-adipogenic FABP4 and down-regulated pro-adipogenic genes SREBF1 and FASN, causing dephosphorylation of IRS-1 and p70S6K, while activating GSK3α/β and BAD. Therefore, HNE could play important roles in proliferation and differentiation of preadipocytes and in metabolic dysfunction of adipose tissue, while it seems that insulin and metformin might reverse the HNE impaired adipogenesis.

Combined metformin and insulin treatment reverses metabolically impaired omental adipogenesis and accumulation of 4-hydroxynonenal in obese diabetic patients

ObjectiveObesity-associated impaired fat accumulation in the visceral adipose tissue can lead to ectopic fat deposition and increased risk of insulin resistance and type 2 diabetes mellitus (T2DM). This study investigated whether impaired adipogenesis of omental (OM) adipose tissues and elevated 4-hydroxynonenal (4-HNE) accumulation contribute to this process, and if combined metformin and insulin treatment in T2DM patients could rescue this phenotype. MethodsOM adipose tissues were obtained from forty clinically well characterized obese individuals during weight reduction surgery. Levels of 4-HNE protein adducts, adipocyte size and number of macrophages were determined within these tissues by immunohistochemistry. Adipogenic capacity and gene expression profiles were assessed in preadipocytes derived from these tissues in relation to insulin resistance and in response to 4-HNE, metformin or combined metformin and insulin treatment. ResultsPreadipocytes isolated from insulin resistant (IR) and T2DM individuals exhibited lower adipogenesis, marked by upregulation of anti-adipogenic genes, compared to preadipocytes derived from insulin sensitive (IS) individuals. Impaired adipogenesis was also associated with increased 4-HNE levels, smaller adipocytes and greater macrophage presence in the adipose tissues. Within the T2DM group, preadipocytes from combined metformin and insulin treated subset showed better in vitro adipogenesis compared to metformin alone, which was associated with less presence of macrophages and 4-HNE in the adipose tissues. Treatment of preadipocytes in vitro with 4-HNE reduced their adipogenesis and increased proliferation, even in the presence of metformin, which was partially rescued by the presence of insulin. ConclusionThis study reveals involvement of 4-HNE in the impaired OM adipogenesis-associated with insulin resistance and T2DM and provides a proof of concept that this impairment can be reversed by the synergistic action of insulin and metformin. Further studies are needed to evaluate involvement of 4-HNE in metabolically impaired abdominal adipogenesis and to confirm benefits of combined metformin-insulin therapy in T2DM patients.