Macrophage Area Content and Phenotype in Hepatic and Adipose Tissue in Patients with Obesity Undergoing Roux-en-Y Gastric Bypass.

OBJECTIVE: To investigate hepatic and adipose tissue macrophage content in subjects with obesity and the role of adipose tissue macrophages in weight loss-induced improved insulin sensitivity (IS).

METHODS: A cross-sectional and a longitudinal study were combined to investigate the role of macrophages in subcutaneous (SAT) and visceral (VAT) adipose tissue and the liver in obesity-induced impaired IS and improvements with weight loss. Macrophage markers (CD68, CD163, and CD206) in SAT, VAT, and the liver from patients with obesity were investigated. The same macrophage markers were investigated in SAT from 18 patients with obesity before and ∼18 months after a diet- and Roux-en-Y gastric bypass-induced weight loss.

RESULTS: SAT macrophage markers did not decrease with weight loss, but macrophage concentration may have increased, concomitant with improved IS. Hepatic macrophage markers did not correlate to VAT mass or macrophage markers, but they were higher in patients with obesity compared with patients without obesity. Hepatic anti-inflammatory macrophage markers correlated positively with hepatic IS. VAT and SAT macrophage markers did not correlate.

CONCLUSIONS: The results indicate that decreased SAT macrophage content is not a primary driver for weight loss-induced IS improvements, but a better hepatic CD163 and CD206 macrophage profile may contribute to improved glycemic control. SAT macrophage markers were not predictive for VAT macrophage markers.