Original Article Adipocyte-Derived Serum Amyloid A3 and Hyaluronan Play a Role in Monocyte Recruitment and Adhesion

Obesity is characterized by adipocyte hypertrophy and macrophage accumulation in adipose tissue. Monocyte che-moattractant protein-1 (MCP-1) plays a role in macro-phage recruitment into adipose tissue. However, other adipocyte-derived factors, e.g., hyaluronan and serum amy-loid A (SAA), can facilitate monocyte adhesion and chemo-taxis, respectively. The objective was to test the potential involvement of these factors in macrophage recruitment. Differentiated 3T3-L1 adipocytes made hypertrophic by growth in high glucose conditions were used to study SAA and hyaluronan regulation in vitro. Two mouse models of obesity were used to study their expression in vivo. Nuclear factor-B was upregulated and peroxisome proliferator–activated receptor (PPAR) was down-regulated in hypertrophic 3T3-L1 cells, with increase