A Subset of Human Uterine Endometrial Macrophages is Alternatively Activated

Abstract

PROBLEM: Human uterine macrophages must maintain an environment hospitable to implantation and pregnancy and simultaneously provide protection against pathogens. Although macrophages comprise a significant portion of leukocytes within the uterine endometrium, the activation profile and functional response of these cells to endotoxin are unknown. METHOD OF STUDY: Flow cytometric analysis of surface receptors and intracellular markers expressed by macrophages isolated from human endometria was performed. Uterine macrophages were stimulated with LPS. Cytokines, chemokines, and growth factors expressed by these cells were analyzed using Bio-Plex analysis. RESULTS: CD163(high) human endometrial macrophages constitutively secrete both pro- and anti-inflammatory cytokines as well as pro-angiogenic factors and secretion of these factors is LPS-inducible. CONCLUSION: A major population of human uterine macrophages is alternatively activated. These cells secrete factors in response to LPS that are involved in the activation of immune responses and tissue homeostasis.