Functional Analysis of Botulinum Hemagglutinin (HA)

Protocol and Demographics of the RELY-CD Study: Assessing Long-Term Clinical Response to Botulinum Neurotoxin in Cervical Dystonia

The RELY-CD study investigated the long-term clinical response to botulinum neurotoxin type A in cervical dystonia within a multicenter, real-world setting. This retrospective study focused on patients treated with complex-free (incobotulinumtoxinA) and complex-containing (onabotulinumtoxinA and abobotulinumtoxinA) BoNT/A formulations over an up to 10-year period. The novel dose-effect parameter "DEff" was introduced to quantify the relationship between dose adjustments and clinical outcomes, enabling the identification of partial treatment failures. The primary endpoint was a comparison of a clinically meaningful worsening in DEff in treatment year 7 compared to year 2 between complex-free and complex-containing botulinum neurotoxin type A. The RELY-CD study provides unique insights into long-term treatment patterns, clinical resistance phenomena, and the implications of formulation differences on treatment outcomes, addressing a critical gap in the literature on real-world botulinum neurotoxin type A application. The study methodology, including the definition and calculation of the novel DEff, as well as clinical baseline characteristics, are presented.

Pathogenicity and virulence of Clostridium botulinum

Clostridium botulinum, a polyphyletic Gram-positive taxon of bacteria, is classified purely by their ability to produce botulinum neurotoxin (BoNT). BoNT is the primary virulence factor and the causative agent of botulism. A potentially fatal disease, botulism is classically characterized by a symmetrical descending flaccid paralysis, which is left untreated can lead to respiratory failure and death. Botulism cases are classified into three main forms dependent on the nature of intoxication; foodborne, wound and infant. The BoNT, regarded as the most potent biological substance known, is a zinc metalloprotease that specifically cleaves SNARE proteins at neuromuscular junctions, preventing exocytosis of neurotransmitters, leading to muscle paralysis. The BoNT is now used to treat numerous medical conditions caused by overactive or spastic muscles and is extensively used in the cosmetic industry due to its high specificity and the exceedingly small doses needed to exert long-lasting pharmacological effects. Additionally, the ability to form endospores is critical to the pathogenicity of the bacteria. Disease transmission is often facilitated via the metabolically dormant spores that are highly resistant to environment stresses, allowing persistence in the environment in unfavourable conditions. Infant and wound botulism infections are initiated upon germination of the spores into neurotoxin producing vegetative cells, whereas foodborne botulism is attributed to ingestion of preformed BoNT. C. botulinum is a saprophytic bacterium, thought to have evolved its potent neurotoxin to establish a source of nutrients by killing its host.

The Immunology of Botulinum Toxin Therapy: A Brief Summary

Like all proteins foreign to the human body, also botulinum toxin (BT) is antigenic and may stimulate an immune response with formulation of antibodies (BT-AB). Affected patients may no longer respond to BT therapy and various degrees of BT-AB related therapy failure (ABF) may result. We want to review the immunological interactions between BT and BT-AB, the prevalence, the time course and the risk factors for BT-AB formation as they are related to the treatment algorithms, the patient's immune system and to exogenic factors. Special emphasis is placed on various features of the BT drugs including the specific biological activity (SBA) as a predictor of their antigenicity. Quantitative detection of BT-AB by the mouse diaphragm assay will be demonstrated. As ABF may have serious consequences for patients affected, careful risk factor analysis is warranted to reduce them wherever possible.

Outcome Using Either Intradermal Botox Injection or Endoscopic Thoracic Sympathectomy for Patients with Primary Palmar Hyperhidrosis: A Comparative Study

Hyperhidrosis, or excessive sweating, negatively impacts patients both physically and psychologically. It may be primary or secondary: the primary form is a benign condition, with its growing prevalence reaching 5% recently. Its medical treatments are transitory. Objectives: Comparison of the outcomes of patients with primary palmar hyperhidrosis (PPH) after intradermal Botox injection (IBI) versus endoscopic thoracic sympathectomy (ETS). Methods: Forty patients were randomly divided into two equal groups. Patients in the IBI group received an intradermal injection of a botulinum toxin A. Patients in the EST group received endoscopic electrocautery of the sympathetic chain. The patients were evaluated biweekly for 12 weeks, and patient satisfaction by outcome was evaluated using a 4-point satisfaction score. Results: At 12 weeks, 60% of the IBI group patients had maintained an improvement. Meanwhile, 40% of the patients were improved compared to pre-intervention scores, despite deterioration after remarkable improvement. On the other hand, 80% of ETS group patients maintained their Hyperhidrosis Disease Severity Scale (HDSS) up until the end of follow-up. Patient satisfaction scores were significantly higher for the IBI group compared to the ETS group. Conclusions: Intradermal Botox injection is a simple, safe, non-invasive, and effective therapeutic modality for PPH and achieved higher patient satisfaction compared to ETS.