Growth Hormone Stimulates Murine Macrophage Migration during Aging.

Background: Age-related impairments in macrophage functions have important consequences for the health of the elderly population. The aging process is also accompanied by a reduction in several hormones, including growth hormone (GH). Previous studies have shown that this hormone can affect macrophage activity in young individuals; however, the biological effects of GH stimulation on macrophages during aging have not yet been elucidated.

Objective: The aim of this work was to investigate the in vitro effects of GH on peritoneal macrophages from aged mice.

Methods: Peritoneal macrophages isolated from young (4 months-old) and old (12-15 months-old) mice were treated in vitro with 100 ng/mL of GH for 24 hours. After treatment, cells were analysed for cell morphology, reactive oxygen species (ROS) production, expression of integrins, cell adhesion to extracellular matrix molecules, and migration in transwell chambers.

Results: Although GH-treated cells from old mice exhibited decreased ROS production, we did not observe the effects of GH on macrophage morphology or macrophage phagocytic activity in young and old mice-derived cell cultures. Macrophages from old mice had increased adhesion to laminin and fibronectin substrates, as did cells obtained from young mice treated with GH, but no change was observed in the expression of integrin receptors. Furthermore, cells from old mice exhibited increased migration compared to young mice and a significant increase in macrophage migration was observed under GH stimulation.

Conclusion: Our results showed that GH can interfere with the motility of macrophages from old mice, advancing our understanding of the interactions between the immune and neuroendocrine systems during aging.