Hydrodynamic models for the diffusivity of type A botulinum neurotoxin

Abstract

The times-to-maximum effect of type A botulinum neurotoxin (BoNT/A) depend to some extent on biophysical and biochemical variables. These times range from <3 h (isolated nerve-muscle preparations) to 1-3 weeks (healthy human volunteers). Hydrodynamic equations were solved for different models, some of which produced values of the diffusion coefficient (D) that are comparable to those of other proteins. Other results differed by up to five orders of magnitude. Because the in vivo findings were not related to an unusually small value for D, we propose that there is a protective reservoir for BoNT/A in vivo and possibly for other serotypes.

Kinetic and Reaction Pathway Analysis in the Application of Botulinum Toxin A for Wound Healing

“…Kinetic models could help to identify what research gaps exist and which ones can be experimentally or clinically resolved. One gap that could be experimentally verified is to determine if the intracellular diffusion of botulinum toxin A [ 67 ] is influenced by other coinjected materials, for example, epinephrine and local anesthetics (lidocaine, Xylocaine), compounds that have been considered in controlling local diffusion and predicting the extent of this toxin's paralytic effect [ 15 , 32 ].…”