Medical Aesthetics Clinics UK

BoNT-A is a neurotoxin secreted by Clostridium Botuli and purified to be used in therapeutics. There is seven serotypes ( A,B,C,D,E,F,G) but only BoNT-A and BoNT-B are licensed for focal dystonia treatment. BoNT-A is a polypeptide with 2 chains linked by a disulfuric bridge. The heavy chain is responsible of the specific binding of the BoNT-A to the cholinergic fibers. The limited action on cholinergic fibers due to this specific bindings is one factor of safety of the BoNT-A . The light chain is responsible of the enzymatic action of the BoNT-A, which cuts a membrane vesicle protein ( called SNAP-25), making the release of the acetylcholine in the synaptic cleft impossible. When the release of the acetylcholine is blocked, there is no more signal from the nerve to the muscle , therefore the muscle is less able to contract. Also there is no more signal between the nerve and the glands ( sweat or salivary glands for example), and the gland stops secreting. This blockage of the release of the acetylcholine is transient, as there is sprouting of the nerve terminals and also synthesis of new membrane vesicle proteins.

Hyperhidrosis describes excessive sweating from the Eccrine gland. It’s often a familial condition, which is still not well understood; It’s lilkely to be due to an overactivity of the autonomic nervous system. Sweating is a way of the body to cope with heat, and avoid hyperthermia in hot weather or when exercising. Excessive sweating can be due to illness associated with high temperature, metabolic conditions such as hyperthyroidism, spinal injury and various drugs such as antidepressants. It can be primary, which means with no obvious causes and in that cases it is often familial. Primary hyperhidrosis can start very early in life and can affect different sites (armpits, hands, feet, face, scalp, trunk, back) among different members of the family. It is triggered by anxiety, emotion, hot weather and sometimes physical exercise. Just thinking about it makes the patient sweating.