Does leptin exhibit cytokine-like properties in tissues of pregnancy?

PROBLEM: To determine whether leptin exhibits cytokine-like properties in gestational tissues in light of its homologies with the class I family of cytokines.

METHOD OF STUDY: WISH and JEG3 cells, and amnion and choriodecidua explants, were treated inflammatory modulators (interleukin-1beta [IL-1beta], tumor necrosis factor-alpha [TNF-alpha] and bacterial lipopolysaccharide [LPS]) and leptin production was measured by immunoassay. Other agents known to regulate adipocyte leptin production were also tested for comparative purposes. In addition, WISH cells, JAR cells and placental explants were treated with leptin to assess its effects on production of IL-8, IL-6 and prostaglandin E2 (PGE2).

RESULTS

Leptin production by all cells and tissues studied was unaffected by treatment with IL-1beta (2.5 ng/mL), TNF-alpha (25 ng/mL) and LPS (2.5 microg/mL). Dexamethasone stimulated leptin production over two-fold by WISH and JEG3 cells, whereas insulin also stimulated a two-fold increase in leptin production in JEG3 cells. IL-6 production by JAR cells and placental explants was stimulated (two- to three-fold) by leptin (300 ng/mL). PGE2 production was unaffected.

CONCLUSIONS

Leptin derived from gestational tissues is unlikely to play a role in inflammatory reactions within the placenta, but may regulate placental cytokine production. The physiological significance of amnion-derived leptin remains to be established.