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Botulinum toxin A did not impact wound healing in vitro

Beyond chemoimmobilization, recent in vitro study results suggested that botulinum toxin A injections did not play a significant theraupeutic role for cutaneous wound healing or scar tissue.

Using a cell line of normal human fibroblasts (NHF) and human dermal microvascular endothelial cells (HDMEC), researchers measured the clinical effects of botulinum toxin A (Botox, Allergan) injections in a multicellular culture model. Researchers dissolved botulinum toxin A in phosphate-buffered saline at a concentration of 10.0 IU/mL. They then analyzed the NHF and HDMEC in four concentrations (1.0 IU/4 mL, 2.5 IU/4 mL, 5.0 IU/4 mL and 10.0 IU/4 mL) for cell proliferation and cytokine expression by using viability assays and enzyme-linked immunosorbent assay techniques.

Researchers found that neither cell proliferation nor cytokines and growth factors, including interleukin 6, monocyte chemoattractant protein 2, fibroblast growth factor and vascular endothelial growth factor, were stimulated or inhibited by botulinum toxin A after incubation at 48 and 72 hours.

“The results … do not consistently confirm some of the published clinical and basic data regarding the effects of botulinum toxin A on mature scar tissue,” the researchers wrote. “The present data do not add evidence to suggest a significant therapeutic role of botulinum toxin A injections concerning cellular effects on fibroblasts and endothelial cells.”

They also said additional studies, which include “patient-specific cells of hypertrophic scars,” are necessary to define more clearly what role botulinum toxin A may play in treating mature scar tissue.