The Benefits of Botulinum Neurotoxin Treatment in a Multitude of Medical Conditions

Botulinum neurotoxins (BoNTs) are responsible for botulism in humans and vertebrates, being one of the six most catastrophic potential bioterrorism agents. This are ~150 kDa proteins, assembled as a ~50 kDa light chain (LC) and a ~100 kDa heavy chain (HC). The LC acts like a zinc metalloproteinase that cleaves three proteins in neurons, members of the SNARE (Soluble N-ethylmaleimide sensitive fusion attachment protein receptors) family: VAMP (vesicle-associated membrane protein) / synaptobrevin, SNAP-25 (synaptosomal-associated protein 25) and syntaxin. After cleavage of any of this proteins, neurotransmission is blocked and flaccid paralysis of the muscle is installed. This extraordinary restricted tropism for the cholinergic presynaptic membrane makes this drug unique regarding its toxicity, pharmacological and therapeutic use. Taking into consideration the potential of this substance, this paper aims to summarize the most relevant data regarding the mechanism of actions and its main clinical applications, in order to improve medical practice. Therefore, we presented the mechanism of action in order to understand its usage in different pathologies, such as dystonias, spasticity, nephrologic and urologic conditions, cosmetic use, depression, gastroenterologic and proctologic diseases, dermatologic conditions, pathologies specific to plastic surgery and also the role of BoNT therapy in pain management. It is well documented in the literature that important discoveries have been made through recent experimental and clinical studies. Even so, there is still much to learn about the therapeutic action of this drug in terms of molecular and pathophysiological mechanisms, in order to benefit of the whole healing potential of this amazing toxin.