Botulinum toxin in the management of blepharospasm: current evidence and recent developments

Botulinum toxin A dissolving microneedles for hyperhidrosis treatment: design, formulation and in vivo evaluation

Multiple periodic injections of botulinum toxin A (BTX-A) are the standard treatment of hyperhidrosis which causes excessive sweating. However, BTX-A injections can create problems, including incorrect and painful injections, the risk of drug entry into the bloodstream, the need for medical expertise, and waste disposal problems. New drug delivery systems can substantially reduce these problems. Transdermal delivery is an effective alternative to conventional BTX-A injections. However, BTX-A's large molecular size and susceptibility to degradation complicate transdermal delivery. Dissolving microneedle patches (DMNPs) encapsulated with BTX-A (BTX-A/DMNPs) are a promising solution that can penetrate the dermis painlessly and provide localized translocation of BTX-A. In this study, using high-precision 3D laser lithography and subsequent molding, DMNPs were prepared based on a combination of biocompatible polyvinylpyrrolidone and hyaluronic acid polymers to deliver BTX-A with ultra-sharp needle tips of 1.5 ± 0.5 µm. Mechanical, morphological and histological assessments of the prepared DMNPs were performed to optimize their physicochemical properties. Furthermore, the BTX-A release and diffusion kinetics across the skin layers were investigated. A COMSOL simulation was conducted to study the diffusion process. The primary stability analysis reported significant stability for three months. Finally, the functionality of the BTX-A/DMNPs for the suppression of sweat glands was confirmed on the hyperhidrosis mouse footpad, which drastically reduced sweat gland activity. The results demonstrate that these engineered DMNPs can be an effective, painless, inexpensive alternative to hypodermic injections when treating hyperhidrosis.

Sensory Symptoms Associated with Aesthetic Botulinum Toxin A Treatments

A retrospective review of patients who switched from onabotulinumtoxinA (onaA) and/or abobotulinumtoxinA (aboA) to incobotulinumtoxinA (incoA) found anecdotal reports of differences in "feel," including a "lighter" feel or treatment-associated tightness. We surveyed the frequency of these sensations as an initial proof of concept of toxin proprioception among our patients who switched toxins.

METHODS

Seventy-nine patients who had past facial aesthetic treatments with more than one botulinum toxin A (BoNT/A) formulation completed a questionnaire on their experience of treatment-associated sensations, including stiffness or a frozen feeling.

RESULTS

Treatment-associated sensations of tightness (47.3%), headache (41.8%), heaviness (38.2%), feeling frozen (29.1%), stiffness (20.0%), and weakness (20.0%) were reported by 55 of 79 patients. Furthermore, 78.2% of 55 patients noted an interformulation sensory difference. Of 79 patients surveyed, 68.4% of onaA-treated patients associated sensations with onaA, 39.1% of aboA-treated patients associated sensations with aboA, and 12.2% of incoA-treated patients associated sensations with incoA.

CONCLUSIONS

Some patients reported a different feel between toxins, and the difference in frequency of treatment-associated sensation varies between the different formulations used. Given the fine coordination of facial expressive muscles, we suspect that associated proprioceptive afferents are involved. Our findings confirm that post-toxin treatment-associated sensations can be detected by some patients, and this is likely due to the variations between the formulations. Failing to advise patients of this before switching formulations may cause a misperception that the treatment is not working well or that its effect has worn off prematurely, and some patients may consider switching formulations to reduce these conscious proprioceptive sensations.

Outcomes of a regional variant of botulinum toxin type A in the treatment of essential blepharospasm and hemifacial spasms: A retrospective study

Purpose:

The aim of this study was to report the outcomes of a regional variant of botulinum toxin type A (BtA) in essential blepharospasm and hemifacial spasm.

Methods:

The medical records of all patients with facial dystonias, who received at least one dose of BtA between May 2016 and April 2017 were retrospectively evaluated. The pre- and post-injection severity of symptoms, graded using the Jankovic rating system for essential blepharospasm and the Samsung Medical Center grading system for hemifacial spasm, the complications after each sitting, and the mean symptom-free interval were recorded. A correlation analysis was done to identify factors associated with longer symptom-free intervals. A P value < 0.05 was considered statistically significant.

Results:

The mean age at presentation was 56.62 ± 10.56 years. The mean duration of follow-up was 1.86 ± 2.06 years. The modal disease severity reduced from 5 to 0 in essential blepharospasm and from 2 to 0 in hemifacial spasm a week after injection of botulinum toxin. The mean symptom-free intervals with doses of 20, 22.5, 25, 30, and 50 units were 102.1 ± 44.7, 132.4 ± 35.3, 147.2 ± 61.6, 124.4 ± 55.1, and 142.4 ± 59.7 days, respectively. The commonest complication was lagophthalmos (26.3%; n = 20). Injections for primary dystonias were associated with longer disease-free intervals than those for secondary dystonias (P = 0.02). In nine sittings, the dose was increased for increased severity or presumed resistance, which resulted in a significant increase in the symptom-free interval (P = 0.004) without an increased incidence of complications (P = 0.48).

Conclusion:

BtA is safe and effective in the treatment of facial dystonias. The drug is more efficacious for primary facial dystonias.

Personality profile of the primary blepharospasm (BSP): An investigation using the Minnesota Multiphasic Personality Inventory

OBJECTIVE

To explore whether patients with blepharospasm (BSP) have abnormal personality traits by the Minnesota Multiphasic Personality Inventory (MMPI) questionnaire.

METHOD

The personality profiles of patients with BSP and its relationship with clinical characteristics were assessed in this research. 46 patients with BSP and 33 age-and-gender matched healthy controls were assessed using the MMPI questionnaire. The scores of three validity scales and ten clinical scales were calculated and compared. Then the relationship between those scales and clinical characteristics of patients with BSP was analyzed in the BSP group.

RESULTS

It was found that patients with BSP scored significantly higher than healthy controls on the D, Hy, Pt clinical scales. The peak values of profiles were Hy, D, Hs scale scores. However, there was no statistical relationship between the clinical scales of MMPI and the clinical characteristics of BSP after Bonferroni Correction.

CONCLUSION

The findings indicated that MMPI could be a useful psychometric tool to characterize a specific pattern of the personality of BSP patients and BSP patients may have avoidant and somatization personality characteristics.

Long-term treatment of blepharospasm with botulinum toxin A: a service-based study over a 16-year follow-up in southern China

OBJECTIVE

To elucidate the effect of long-term treatment with botulinum toxin A (BTX-A) for blepharospasm. Prevalence data and clinical features in southern China and influencing factors for selecting BTX-A treatment were explored.

METHODS

We collected data retrospectively from 338 consecutive patients diagnosed with blepharospasm over 16 years to assess prevalence data and clinical features. Thereafter, all patients were classified into BTX-A (n = 135) or non-BTX-A (n = 203) treatment groups according to the patients' requests in order to explore the factors influencing whether BTX-A treatment was chosen. Furthermore, dynamic follow-up data were analyzed to evaluate the long-term efficacy in the BTX-A group.

RESULTS

The prevalence was 23.3 per million, with an onset age of 50.3 ± 12.3 years and a female:male ratio of 2.4:1; the most common symptom was excessive blinking (91.2%). The symptom severity and psychological assessment scores were significantly decreased by treatment with BTX-A (p < 0.01), and there was no significant difference in response duration with the prolongation of BTX-A injections. Adverse events occurred 52 times (5.0%) among 1038 injections. The symptom severity and psychological assessment scores and the occurrence of eye-opening difficulty were higher, and medical expenses and the symptom tolerability rate were lower in the BTX-A group than in the non-BTX-A group (p < 0.05).

CONCLUSION

The onset age was earlier than that in Western countries. However, starting BTX-A treatment early is justified, even though a higher dosage was needed to maintain reliable long-term efficacy. Additionally, symptom severity and medical expenses are the primary factors affecting whether patients select BTX-A treatment.

Treatment of blepharospasm and Meige's syndrome with abo- and onabotulinumtoxinA: long-term safety and efficacy in daily clinical practice

INTRODUCTION

Thirty years after their approval, botulinum toxin injections still are the first-line therapy for blepharospasm. The aim of our study was to analyze long-term data concerning safety and efficacy in a large cohort over decades.

METHODS

Treatment data of all patients with blepharospasm and Meige´s syndrome in our outpatient clinic having undergone at least three subsequent treatment sessions with current onabotulinumtoxinA or abobotulinumtoxin A were analyzed with respect to the course of dose, effect duration, side effects, patients´ satisfaction and occurrence/reasons for treatment discontinuation.

RESULTS

The observation period was up to 18 years for onabotulinumtoxinA and 29 years for abobotulinumtoxinA with a total of 1778 and 9319 treatment sessions in 69 patients with onabotulinumtoxinA, 281 with abobotulinumtoxin A and 2 of these having used both products. The dose increased in the first years followed by a stable dose in the following years. The mean dose was 39.1/198.7 mouse units (onabotulinumtoxinA/abobotulinumtoxinA). In over 25% of all sessions, inhibition of the eyelid opening was effectively treated with pretarsal injections. The most common adverse events included ptosis (4%/5%), epiphora/sicca (4%/5%), double vision (1%/1%) and facial asymmetry (1%/1%). Reasons for therapy discontinuation were change to a nearby doctor, age, other diseases, spontaneous improvement, side effects or possible treatment failure. Only one patient was tested positive for neutralizing antibodies against botulinum toxin A.

CONCLUSION

The treatment of blepharospasm and Meige's syndrome with onabotulinumtoxinA and abobotulinumtoxinA is safe and effective, also over a long observation period of up to 29 years.

A trial of a mechanical device for the treatment of blepharospasm

BACKGROUND

Idiopathic blepharospasm (IB) is a rare but well-characterised adult onset focal dystonia that may cause severe visual disability. The most effective treatment is with periodic injections of botulinum toxin (BTX) into the pre-tarsal and/or pre-septal orbicularis oculi muscles bilaterally. However, even with treatment, practical visual function often remains compromised. A subset of IB sufferers find that eye opening improves with a focal unilateral digital pressure usually on a specific point on the temple. This is known as a 'sensory trick'. We have developed a spectacle mounted device ('Pressop') to apply continuous individually localised focal pressure on the temple to mimic the effect of finger pressure. The aim of the study was to determine if the 'sensory trick' could be replicated by Pressop and if the interval between BTX treatments could thereby be extended.

SUBJECTS/METHODS

Study participants had three clinic visits-an initial screening assessment, a visit 2 weeks before the next injection was due when the device was fitted, and one 2 weeks later to assess the response to Pressop. A CDQ 24 and device-specific feedback questionnaire were completed and comparison photographs were taken. Repeat BTX injections were administered at the third visit.

RESULTS

Of 58 patients with typical IB recruited to the trial, 39 reported an effective focal finger pressure sensory trick. 56 completed the trial, more than 50% of whom reported some benefit using Pressop; 18% had substantial improvement, sustained for up to 5 years. Improvement could occur in those without an effective sensory trick, therefore there was no significant correlation between using a sensory trick and benefiting from 'Pressop'. There was a trend towards the responders having greater improvement in CDQ24 total score than non-responders but this was not statistically significant.

CONCLUSIONS

We recommend a trial of this simple safe device as a means of augmenting visual function in all IB patients.

Botulinum Neurotoxin-A Injected Intrastriatally into Hemiparkinsonian Rats Improves the Initiation Time for Left and Right Forelimbs in Both Forehand and Backhand Directions

Forelimb stepping is a widely used test for the assessment of forelimb akinesia in hemiparkinsonian (hemi-PD) rats. The initiation time (IT) is considered the most sensitive parameter in the stepping test procedure. Here we propose a novel, reliable, and simple method for the measurement of IT of both forelimbs in both forehand and backhand directions in rats. Evaluating the same videos taken for quantifying adjusting steps, IT measurements were done without additional experiments. This is in contrast to the classical approach introduced by Olsson et al. (1995), in which separate experiments are necessary. We successfully applied our approach to hemi-PD rats intrastriatally treated with botulinum neurotoxin-A (BoNT-A). In naïve rats, an IT of about 0.62 s was found, and in right-sided hemi-PD rats the IT of the left forepaw increased to about 3.62 s. These hemi-PD rats showed, however, reduced ITs of the impaired left forepaws 1 month and the second time 7 months after induction of hemi-PD via the injection of 1 ng BoNT-A into the ipsilateral striatum, depending on post BoNT-A survival time. The method described offers the possibility of a precise and animal-friendly evaluation of IT in rats, including the beneficial effect of BoNT-A treatment in hemi-PD rats.

Pharmacological differences and clinical implications of various botulinum toxin preparations: a critical appraisal

Three different type A botulinum neurotoxins (BoNTAs) - onabotulinumtoxinA, abobotulinumtoxinA and incobotulinumtoxinA) - are currently marketed in Europe to treat several conditions. Differences between BoNTA preparations, which depend on their specific biotypes and manufacturing processes, lead to clinically relevant pharmacotherapeutic dissimilarities. All three available products are separately recognized and reviewed in American Academy of Neurology guidelines. The neurotoxin load/100U is likewise different among the different BoNTAs, with the result that the specific potency of the 150kD BoNTA neurotoxin is calculated as 137 units/ng for onabotulinumtoxinA, 154 units/ng for abobotulinumtoxinA, and 227 units/ng for incobotulinumtoxinA. It is important for clinicians to have all three BoNTAs available in order to choose the most suitable preparation for the specific indication in the single patient. Commercially available BoNTAs must be recognized as different from one another, and therefore as non-interchangeable. The essential experience of the clinician is of the utmost importance in choosing the most appropriate treatment.

Effect of Botulinum Toxin A Treatment on Eyelid Pressure in Eyes with Blepharospasm

OBJECTIVE

To determine the effect of botulinum toxin A (BTX-A) on the eyelid pressure in patients with benign essential blepharospasm (BEB).

METHODS

Twenty normal volunteers (10 men, 10 women; average age 59.7 ± 11.3 years) and 33 patients (12 men, 21 women; average age 61.1 ± 14.7 years) with BEB were studied. The upper and lower eyelid pressures were measured with a blepharo-tensiometer in the normal subjects (N group). The eyelid pressures and intraocular pressures (IOP) were measured before and after the BTX-A injections in the BEB patients (B group).

RESULTS

The mean eyelid pressure in the N group was 31.0 ± 6.8 mmHg for the upper eyelid and 29.9 ± 6.5 mmHg for the lower eyelid (P > 0.05). The mean eyelid pressure in the B group before treatment was 35.3 ± 7.0 mmHg for the upper eyelid and 37.8 ± 6.6 mmHg for the lower eyelid. The eyelid pressure in the B group was significantly higher than in the N group for the upper and lower eyelids (both P < 0.001). The eyelid pressure was significantly decreased after BTX-A treatment for the upper (29.9 ± 7.5 mmHg) and the lower (32.8 ± 7.0 mmHg) eyelids (both P < 0.001). The mean IOP was 15.1 ± 2.9 mmHg before, and it significantly decreased to 14.5 ± 2.8 mmHg (P = 0.020) after the BTX-A injections. The IOP was significantly correlated with the lower eyelid pressure (P = 0.0435), but not with the upper eyelid pressure (P = 0.175).

CONCLUSION

The eyelid pressure was higher in the patients with BEB. The eyelid pressure and the IOP were significantly reduced after the BTX-A injections. In addition, the IOPs were significantly correlated with the eyelid pressure of the lower eyelid.