Phosphatidic Acid Has a Potential to Promote Hair Growth In Vitro and In Vivo, and Activates Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Kinase in Hair Epithelial Cells

In a study from 2003, researchers investigated the effects of phosphatidic acid (PA) on hair growth, both in vitro using murine hair epithelial cells and in vivo with a murine model. They found that PA significantly promoted the growth of hair epithelial cells and epidermal keratinocytes, more so than lysophosphatidic acid. Additionally, PA was effective in inducing the anagen (growth) phase of the hair cycle in mice. The study also explored the mechanisms behind PA's effects, revealing that it activates the MEK-1/2 enzyme and increases its expression, which is part of the mitogen-activated protein kinase cascade involved in cell proliferation. Furthermore, PA was able to counteract the growth-inhibiting and apoptotic effects of transforming growth factor beta1, a protein that can induce the catagen (regression) phase in the hair cycle. These findings suggest that PA's ability to promote hair growth may be due to its action on specific cellular pathways that encourage cell proliferation and prevent apoptosis.