Macrophage Populations in Visceral Adipose Tissue from Pregnant Women: Potential Role of Obesity in Maternal Inflammation

Abstract

Obesity is associated with inflammatory changes and accumulation and phenotype polarization of adipose tissue macrophages (ATMs). Obese pregnant women have alterations in adipose tissue composition, but a detailed description of macrophage population is not available. In this study, we characterized macrophage populations in visceral adipose tissue (VAT) from pregnant women with normal, overweight, and obese pregestational weight. Immunophenotyping of macrophages from VAT biopsies was performed by flow cytometry using CD45 and CD14 as markers of hematopoietic and monocyte linage, respectively, while HLA-DR, CD11c, CD163, and CD206 were used as pro- and anti-inflammatory markers. Adipocyte number and size were evaluated by light microscopy. The results show that pregnant women that were overweight and obese during the pregestational period had adipocyte hypertrophy. Two different macrophage populations in VAT were identified: recruited macrophages (CD45+CD14+), and a novel population lacking CD45, which was considered to be a resident macrophages subset (CD45−CD14+). The number of resident HLA−DRlow/− macrophages showed a negative correlation with body mass index (BMI). Both resident and recruited macrophages from obese women expressed higher CD206 levels. CD11c expression was higher in resident HLA-DR+ macrophages from obese women. A strong correlation between CD206 and CD11c markers and BMI was observed. Our findings show that being overweight and obese in the pregestational period is associated with adipocyte hypertrophy and specific ATMs populations in VAT.

Adipose tissue function in healthy pregnancy, gestational diabetes mellitus and pre-eclampsia

“…There was evidence of a heterogeneous response where, when those who had gestational weight loss were excluded, obese women showed an increase in adipocyte number [38]. Third trimester SAT [39,40] and VAT [41] adipocyte hypertrophy has also been reported in obese compared to lean third trimester pregnant women. Others have reported that obese women had fewer adipocytes and increased evidence of necrosis and apoptosis suggesting a higher adipocyte turnover and greater adipose tissue remodelling compared to lean pregnant women [39].…”

Ceramide kinase regulates TNF-α-induced immune responses in human monocytic cells

“…CD11b expression was reported to be elevated in obese individuals which associated with the development of metabolic syndrome 34 . CD11c expression was found to be higher in adipose-resident HLA-DR + macrophages from obese women 35 . Since TNF-α is invariably elevated in obesity and metabolic syndrome, expression of inflammatory phenotypic markers in monocytes/macrophages could have been induced by TNF-α.…”

Ceramide Kinase Regulates TNF-α-induced Immune Responses in Human Monocytic Cells

“…CD11b expression was reported to be elevated in obese individuals which associated with the development of metabolic syndrome 26 . CD11c expression was found to be higher in adipose-resident HLA-DR⁺ macrophages from obese women 27 . Since TNF-α is invariably elevated in obesity and metabolic syndrome, expression of inflammatory phenotypic markers in monocytes/macrophages could have been induced by TNF-α.…”