Management of bladder, prostatic and pelvic floor disorders

Gastrointestinal Uses of Botulinum Toxin

Botulinum toxin (BT), one of the most powerful inhibitors that prevents the release of acetylcholine from nerve endings, represents an alternative therapeutic approach for "spastic" disorders of the gastrointestinal tract such as achalasia, gastroparesis, sphincter of Oddi dysfunction, chronic anal fissures, and pelvic floor dyssynergia.BT has proven to be safe and this allows it to be a valid alternative in patients at high risk of invasive procedures but long-term efficacy in many disorders has not been observed, primarily due to its relatively short duration of action. Administration of BT has a low rate of adverse reactions and complications. However, not all patients respond to BT therapy, and large randomized controlled trials are lacking for many conditions commonly treated with BT.The local injection of BT in some conditions becomes a useful tool to decide to switch to more invasive therapies. Since 1980, the toxin has rapidly transformed from lethal poison to a safe therapeutic agent, with a significant impact on the quality of life.

Treatment of gastrointestinal sphincters spasms with botulinum toxin A

Botulinum toxin A inhibits neuromuscular transmission. It has become a drug with many indications. The range of clinical applications has grown to encompass several neurological and non-neurological conditions. One of the most recent achievements in the field is the observation that botulinum toxin A provides benefit in diseases of the gastrointestinal tract. Although toxin blocks cholinergic nerve endings in the autonomic nervous system, it has also been shown that it does not block non-adrenergic non-cholinergic responses mediated by nitric oxide. This has promoted further interest in using botulinum toxin A as a treatment for overactive smooth muscles and sphincters. The introduction of this therapy has made the treatment of several clinical conditions easier, in the outpatient setting, at a lower cost and without permanent complications. This review presents current data on the use of botulinum toxin A in the treatment of pathological conditions of the gastrointestinal tract.

Evolution of neurotoxins: from research modalities to clinical realities

In the 1950s, the discovery of anti-nerve growth factor, an immunotoxin stunting sympathetic neural development, signaled the advent of neurotoxins as research modalities. Other selective neurotoxins were discovered in rapid succession. In the 1960s, 6-hydroxydopamine and 6-hydroxydopa were shown to destroy noradrenergic and dopaminergic nerves. Excitotoxins (glutamate, aspartate, and analogs) were discovered in the 1970s. DSP-4 [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine] proved to be selective for noradrenergic destruction, while 5,6- and 5,7-dihydroxytryptamines were relatively selective for serotonin neurons. Additional neurotoxins were discovered, but it was MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) that predominated neurotoxicity research in the 1980s. Eventually, Clostridium botulinum neurotoxin (BoNT), discovered as a "poisonous" principle in the late 1800s, resurfaced in purified and standardized forms as a clinically useful drug. Neurotoxins represent chemical tools, useful not only for discerning neuronal mechanisms and animal modeling of neurological disorders, but also for their use in medicine and potential as treatments for medical disorders. This unit reviews the early discovery of neurotoxins, describes categories of neurotoxins, and finally characterizes their usefulness--first as research tools, and eventually as clinical therapeutic agents.

Botulinum neurotoxin: evolution from poison, to research tool--onto medicinal therapeutic and future pharmaceutical panacea

Botulinum neurotoxin (BoNT), for more than a hundred years, has been a recognized poisonous principle in spoiled food. As its chemical structure became unraveled, and as more knowledge was gained over its mechanism of toxicity, it became clear that BoNT had the potential to act therapeutically as a targeted toxin that could inactivate specific nerve populations, and thus achieve a therapeutic goal. BoNT has evolved over the past 25 years into a viable therapeutic, now being a first line treatment for dystonia, overtly altering the course of progression of this disorder. BoNT is used for hyperhidrosis and gustatory sweating syndrome, alleviation of pain, as a treatment for overactive bladder, achalasia and anal fissure; and it has gained popularity as a cosmetic aid. Many other possible uses are being explored. The greatest potential for BoNT may lie in its being a molecular Trojan Horse - able to carry a specific enzyme or specific drug to the inside of a cancer or other type of cell while bypassing other cells and thereby having little or no ill effect. BoNT's pharmaceutical potential is boundless.