How Does Botox Effect Keloids?

Botulinum toxin type A (BTXA) is effective in the treatment of keloids and other hypertrophic scarring, but the mechanism has not always been clear. The hypothesis behind the early use of BTXA to treat these conditions was that BTXA may inhibit the growth of fibroblasts.

A recent study further explored that mechanism by examining the effects of different concentrations of BTXA on keloid fibroblasts and normal fibroblasts. The results showed that:
• The inhibitory effect was only seen when the concentration of BTXA is or greater than 0.1 U/L.
• BTXA had no significant inhibitory effect on normal fibroblasts compared with keloid fibroblasts.
• BTXA also causes a decrease in TGF-b protein expressed by the TGF-b1 gene. TGF-b1 proteins have been shown to increase the amount of cell proliferation in hypertrophic scars.
• The expression of TGF-b1 gene and protein in keloid fibroblasts was low after treatment with 0.1 U/L BTXA.

The authors conclude that BTXA can inhibit the viability and growth of keloid fibroblasts and that this may be due to BTXA regulating the expression of TGF-b1. This information provides theoretical support to the clinical results that have been observed.