CsA-Induced Hypertrichosis Might Be Caused in Part by Inhibition of TGF-β2 Expression in Dermal Papilla Cells

The study investigated the mechanism behind the hypertrichosis (excessive hair growth) side effect of Cyclosporin A (CsA), an immunosuppressant. The research used cultured human dermal papilla cells (DPCs) and found that CsA decreases the expression of TGF-β2, a protein that regulates hair follicle development and growth. This decrease in TGF-β2 expression is believed to prolong the anagen phase of the hair growth cycle, leading to hypertrichosis. The study also found that key molecules involved in immunosuppressive mechanisms, such as cyclophilins (CyPs), calcineurins (CaNs), and nuclear factor of activated T-cells (NFATs), were expressed in DPCs. The intracellular signaling of CsA to suppress TGF-β2 expression in DPCs might be similar to that of immunosuppression.