Leptin Induces an Inflammatory Phenotype in Lean Wistar Rats

Figure 6

Working hypothesis. Although leptin is constitutively expressed and released by adipocytes, its expression is enhanced during weight gain/fat deposition. We hypothesize that augmented leptin release from growing adipocytes up-regulates adhesion molecules on endothelial cells, which promote the subsequent leukocyte invasion into adipose tissue. The production of inflammatory cytokines by invading leukocytes potentiates leptin synthesis, which will ultimately have detrimental effects on the local microvasculaure. Since blood leaving the mesentery drains directly into the portal circulation, leptin likely plays an important role in the development of obesity-associated nonalcoholic steatohepatitis.