Lipidomics of polarized macrophages in the human adipose tissue

Macrophages are critical components of the innate immune system that adapt their function based on local microenvironmental cues. In adipose tissue, macrophage polarization is intimately linked to metabolic regulation and inflammation. In this pilot study, we performed lipidomic profiling to characterize the phospholipid composition of pro-inflammatory (PI-ATM) and non-inflammatory (NI-ATM) macrophages isolated from visceral adipose tissue of living kidney donors. Tissue samples were processed, and macrophages were isolated and sorted using CD14 and CD16 markers. Lipids were extracted by methyl tert-butyl ether, and differences in the lipidome were analyzed using the optimized UHPLC-MS method. PI-ATM exhibited a higher abundance of lipids across various lipid classes than NI-ATM. Phosphatidylethanolamines and ether lipids derived from phosphatidylethanolamines and phosphatidylcholines were most frequently found among the significantly altered lipids. The majority of significantly altered lipid species contained an octadecenoic aliphatic chain. These findings suggest that alterations in membrane lipid composition - particularly ether lipids and phosphatidylethanolamines - may play a pivotal role in macrophage polarization and adipose tissue inflammation. Our study provides novel insights into the lipidomic regulation of macrophage function in human adipose tissue and identifies potential targets for therapeutic intervention in metabolic disorders.