Neuroleptic-Induced Tardive Cervical Dystonia: Clinical Series of 20 Patients

Efficacy and safety of long-term botulinum toxin treatment for acquired cervical dystonia: a 25-year follow-up

Botulinum toxin A (BoNT/A) is the first-line treatment for idiopathic cervical dystonia (ICD) and is widely used in the clinical setting. To date, scanty data are available on the effectiveness of BoNT in treating acquired cervical dystonia (ACD). Here we present a long-term follow-up of ACD patients treated with BoNT/A that focused on safety and efficacy. The study included subjects who had received at least six treatments of three commercially available BoNT/A drugs [abobotulinumtoxinA (A/Abo), incobotulinumtoxinA (A/Inco) and onabotulinumtoxinA (A/Ona)]. Safety and efficacy were assessed based on patients' self-reports regarding adverse effects (AE), duration of improvement of dystonia and/or pain relief. Global clinical improvement was measured on a six-point scale. 23 patients with ACD were administered 739 treatments (A/Abo in 235, A/Inco in 72, A/Ona in 432) with a mean number of treatments of 31 ± 20 (range 6-76) and duration of 10 ± 6 weeks (range 2-25). The mean dose was 737 ± 292 U for A/Abo, 138 ± 108 U for A/Inco and 158 ± 80 U for A/Ona. The average benefit duration was 89 ± 26 (A/Abo), 88 ± 30 days (A/Inco), and 99 ± 55 days (A/Ona) (p = 0.011); global clinical improvement for all sessions was 4 ± 1. ANOVA one-way analysis indicated that A/Ona had the best profile in terms of duration (p < 0.05), whereas A/Abo had the best pain relief effect (p = 0.002). Side effects were reported in 9% of treatments (67/739), with ten treatments (1%) complicated by two side effects. Most side effects were rated mild to moderate; severe side effects occurred following three treatments with the three different BoNT; two required medical intervention. No allergic reactions were reported. Even after 25 years of repeated treatments, all serotypes of BoNT demonstrate positive effects in treating ACD with long-lasting efficacy and safety.

Clinical Characteristics and Response to Long-Term Botulinum Toxin Type A Therapy in Patients with Cervical Dystonia at a Neurology Clinic

INTRODUCTION

To determine the demographic and clinical characteristics and response to botulinum toxin type A (BoNT-A) therapy in patients with cervical dystonia (CD).

METHOD

A retrospective analysis of the detailed medical records of the patients with CD, followed up at our Botulinum Toxin Outpatient Clinic from 1998 to 2012, was performed. The treatment data were compared between the patients with primary CD and those with secondary CD; between patients receiving BoNT-A treatment for more than 5 years and less than five years, and between first applications and last applications.

RESULTS

Fifty-seven patients (56.15% women) with CD were included in this study. The mean age was 41.01±13.42 years, the mean age at symptom onset was 32.93±15.45 years, and the mean dystonia duration was 8.10±8.5 years. The interval between onset of symptom and first BoNT-A treatment was 5.94±9.06 years, the duration of BoNT-A treatment was 36.13±29.17 months, and the number of applications was 8.48±6.23 in 45 patients with CD who were under treatment with BoNT-A for more than 1 year and had received at least three injections before. There was no difference between the patients with primary and secondary CD in terms of treatment results. The injection interval of the patients receiving BoNT-A treatment for more than 5 years and less than 5 years was 18.37±5.10 and 14.43±2.36 weeks, respectively (p=.001). There were no differences in the other treatment values. The mean doses were 559.00±147.60 vs. 681.66±188.09 units (p=.0001), the durations of improvement were 11.82±2.71 vs. 13.00±4.00 weeks (p=.014), the response scores were 2.71±.3 vs. 3.02±.5 (p=.002), the response ratings were 64.66%±16.18 vs. 71.22%±17.29 (p=.001), and the numbers of muscles applied were 3.15±1.16 vs. 3.51±0.99 (p=.012) in the first and last applications, respectively.

CONCLUSION

There were no differences between the response of the patients with primary and secondary CD. Our results showed a statistically significant increase in the mean dose of BoNT-A, the response rating, the number of muscles applied, the duration of improvement, and the injection interval over time.

The osmolyte trimethylamine N-oxide (TMAO) increases the proteolytic activity of botulinum neurotoxin light chains A, B, and E: implications for enhancing analytical assay sensitivity

Botulism, the disease caused by botulinum neurotoxins (BoNTs), secreted by the spore-forming, anaerobic bacteria Clostridium botulinum, has been associated with food poisoning for centuries. In addition, the potency of BoNTs coupled with the current political climate has produced a threat of intentional, malicious poisoning by these toxins. The ability to detect and measure BoNTs in complex matrixes is among the highest research priorities. However, the extreme potency of these toxins necessitates that assays be capable of detecting miniscule quantities of these proteins. Thus, signal-boosting strategies must be employed. A popular approach uses the proteolytic activity of the BoNT light chain (LC) to catalyze the cleavage of synthetic substrates; reaction products are then analyzed by the analytical platform of choice. However, BoNT LCs are poor catalysts. In this study, the authors used the osmolyte trimethylamine N-oxide (TMAO) to increase the proteolytic activities of BoNT LCs. Their data suggest that concentrated solutions of TMAO induce complete folding of the LCs, resulting in increased substrate affinity and enhanced enzyme turnover. The authors observed increases in catalysis for BoNT serotypes A, B, and E, and this increased proteolytic activity translated into substantial increases in analytical assay sensitivity for these medically relevant toxins.

Development of cell-based assays to measure botulinum neurotoxin serotype A activity using cleavage-sensitive antibodies

Botulinum neurotoxins (BoNTs) are zinc-metalloproteases that cleave components of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) protein complex, inhibiting acetylcholine release into neuromuscular junctions, resulting in flaccid paralysis and eventual death. The potential for the malicious misuse of these toxins as bioweapons has created an urgent need to develop effective therapeutic countermeasures. Robust cell-based assays will be essential for lead identification and the optimization of therapeutic candidates. In this study, the authors developed novel BoNT serotype A (BoNT/A) cleavage-sensitive (BACS) antibodies that only interact with full-length SNAP-25 (synaptosomal-associated protein of 25 kDa), the molecular target of the BoNT/A serotype. These antibodies exhibit high specificity for full-length SNAP-25, allowing the BoNT/A-mediated proteolysis of this protein to be measured in diverse assay formats, including several variations of enzyme-linked immunosorbent assay and multiple immunofluorescence methods. Assays built around the BACS antibodies displayed excellent sensitivity, had excellent reproducibility, and were amenable to multiwell formats. Importantly, these assays provided novel methods for evaluating BoNT/A activity in cellular models of intoxication and allowed for the high-throughput evaluation of experimental compounds.