Efficacy of reconstituted and stored botulinum toxin type A: an electrophysiologic and visual study in the auricular muscle of the rabbit

Bioactivity of abobotulinum toxin is preserved till 2 weeks upon storage at room temperature: Half body comparative study on rabbit model

BACKGROUND

Breakages of the cold chain of botulinum neurotoxin A (BONT-A) preparations is not a rare event and occurs due to several unexpected and unintentional reasons during daily practice and intervention schedules could not be proposed due to the lack of data.

OBJECTIVE

To investigate the heat stability of abobotulinum toxin A (AboBONT-A) in terms of efficacy and duration of action upon storage at room temperature (25°C) for 2, 4, and 8 weeks.

METHODS AND MATERIALS

Twenty rabbits were divided into four groups and received an injection of ideally stored AboBONT-A (Group 1) and stored AboBONT-A for 2 (Group 2), 4 (Group 3), and 8 weeks (Group 4) at room temperature into the anterior auricular muscle. All rabbits were followed up and photographed by weekly for 16 weeks. Grade of paralysis was evaluated by using a modified visual scoring system.

RESULTS

No significant alteration was found in initial potency of stored AboBONT-A at room temperature for up to 4 weeks. Storage at room temperature for 2 weeks did not affect the duration of action (group 2; P = .69), and faster recovery was observed in group 3 and group 4.

CONCLUSION

The bioactivity of AboBONT-A is not altered till 2 weeks upon storage at room temperature.

A comparison study of prabotulinumtoxinA vs onabotulinumtoxinA in myostatin-deficient mice with muscle hypertrophy

Botulinum toxin A (BoNT-A) is used clinically for various muscle disorders and acts by preventing the release of the neurotransmitter acetylcholine into the synapse space. Here, we compared the efficacy of prabotulinumtoxinA (PRA) and onabotulinumtoxinA (ONA) for the reduction in hypertrophy in myostatin-deficient (Mstn^-/- ) mice. Two different BoNT-A products (2.5, 10 and 25 U/kg) were injected to paralyse the hindlimb for 2 months, after which sciatic nerve conduction study, 3D micro-CT, haematoxylin and eosin (H&E) and dystrophin staining were conducted. Administration of BoNT-A products induced denervation-mediated atrophy and alleviated muscle hypertrophy generated in Mstn^-/- mice. The present study revealed that each BoNT-A regulates skeletal muscle size, myofibre number and myofibre diameter in Mstn^-/- mice. The potential applicability of BoNT-A for the treatment of rare muscle hypertrophic diseases was demonstrated. Compared with ONA, PRA had a comparable ability to act in the local area.

Botulinum Toxin Type A: Assessing The Effects on The Brain Stem

BACKGROUND

In this study, our aim is to investigate the possible effects of Botulinum toxin type A administrations in the early and late periods on the brain stem.

METHODS

Eighteen white New Zealand rabbits were used in this study with the subjects being divided into three groups. Group I received 0.05 mL sterile saline to the left anterior auricular muscles. Group II and III were injected with Botulinum toxin type A (Botox, Allergan) to the left anterior auricular muscles. Group II was sacrificed 5 days after application and Group III was sacrificed 12 weeks after application; brain stem tissues were then taken. The samples were examined with Caspase 3, 8, and 9 immunohistochemical stainings.

RESULTS

In the control group with Caspase-3 immune staining, moderate-to-strong immune reactivity was seen in a small number of neurons. In the Caspase-8 and 9 immune stainings, the immune reactive neurons were seen in greater numbers when compared with the Caspase-3 immune reactive neurons. In the early and late period, groups with Caspase-8 and 9 immune stainings, the immune reactive neurons were seen in greater numbers and in the wider area when compared with the Caspase-3 immune reactive neurons. No significant differences were recognized in the Caspase immune stainings between the early and late period groups. The results were statistically supported.

CONCLUSION

It was concluded that Botulinum toxin type A application did not trigger apoptosis in stem cell tissues.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Long-term stability of reconstituted incobotulinumtoxinA: how can we reduce costs of botulinum toxin therapy?

Botulinum neurotoxin (BNT), the biologically active component of botulinum toxin (BT), is a large double-stranded protein susceptible to various physical and chemical influences. All BT type A (BT-A) drugs are stored as powders allowing shelf lives from 24 to 36 months. After reconstitution, the specified shelf life is reduced to 8-24 h. Some studies, however, suggest longer shelf life. We wanted to test the long-term stability of reconstituted BT-A drugs in the hemidiaphragm assay (HDA), a high quality BT potency test. For this incobotulinumtoxinA (INCO) was reconstituted and stored in at 4-8 °C, whilst at various points of time probes of it were taken and potency tested with the HDA. Altogether 18 measurements were performed throughout a period of 52.1 weeks. The paralysis time in the HDA was 67.3 ± 5.2 min (min. 59 min, max. 76 min). The linear regression line was described by y = -0.0163x + 67.582. The paralysis time measured during the first 10 weeks (n = 11) was 67.5 ± 5.3 min, during the last 10 weeks (n = 7) 67.1 ± 4.9 min. Reconstituted INCO does not show reduction of potency throughout 52 weeks as tested by the high quality HDA. Lack of complexing proteins does not de-stabilise INCO. Our data allow un-used reconstituted INCO to be stored for further use. This may have a considerable impact on the costs of BT therapy. Further studies will have to demonstrate sterility of the reconstituted BT drug beyond the so far reported 6 weeks.

Injectable and topical neurotoxins in dermatology: Basic science, anatomy, and therapeutic agents

Botulinum toxin is a potentially deadly anaerobic bacterial toxin that acts by inhibiting release of acetylcholine at the neuromuscular junction, thereby inhibiting contraction of the exposed striated muscle. There are currently 4 botulinum toxin preparations approved by the US Food and Drug Administration (FDA): onabotulinumtoxin, abobotulinumtoxin, incobotulinumtoxin and rimabotulinumtoxin. While significant overlap exists, each product has unique properties and specifications, including dosing, diffusion, and storage. Extensive physician knowledge of facial anatomy, coupled with key differences of the various neurotoxin types, is essential for safe and successful treatments. The first article in this continuing medical education series reviews key characteristics of each neurotoxin, including new and upcoming agents, and provides an anatomic overview of the most commonly injected cosmetic sites.

Botulinum Toxin Conjugated With Silk Fibroin and 4-Hexylresorcinol

PURPOSE

The objective of this study was to evaluate whether silk fibroin (SF) incorporated into 4-hexylresorcinol (4HR) could increase botulinum toxin-A (BTX-A) activity.

MATERIAL AND METHODS

In total, 30 rats were used for this study. The animals were divided into 6 groups according to the injected materials (SA: saline only; SF; 4HR; B2: 2 units of BTX-A; B2 + SF + 4HR: combination of B2, SF, and 4HR; B5: 5 units of BTX-A). Serial sonography was used for the evaluation of muscle thickness after injection. Immunohistochemical staining was used for the evaluation of myosin type II (myo2) and Bcl-2 protein expression.

RESULTS

The relative thickness of the masseter muscle in B2 group was 66.14% ± 4.55% to the preinjection level; in B2 + SF + 4HR group was 54.59% ± 4.83%, and in B5 group was 56.19% ± 8.28%. Any BTX-injected group showed significantly lower value of the relative muscle thickness compared to SA, SF, or 4HR group (P < 0.001 for all). The difference of relative muscle thickness between B2 group and B2 + SF + 4HR group was statistically significant (P < 0.001). The intensity of myo2 immunostaining in B5, B2, and B2 + SF + 4HR group was significantly higher than those in the other groups (P < 0.05).

CONCLUSIONS

When 2 units of BTX was incorporated to SF and 4HR, combination formula showed similar activity to those of 5 units of BTX.

Key Parameters for the Use of AbobotulinumtoxinA in Aesthetics: Onset and Duration

Time to onset of response and duration of response are key measures of botulinum toxin efficacy that have a considerable influence on patient satisfaction with aesthetic treatment. However, there is no overall accepted definition of efficacy for aesthetic uses of botulinumtoxinA (BoNT-A). Mechanical methods of assessment do not lend themselves to clinical practice and clinicians rely instead on assessment scales such as the Frontalis Activity Measurement Standard, Frontalis Rating Scale, Wrinkle Severity Scale, and Subject Global Assessment Scale, but not all of these have been fully validated. Onset of activity is typically seen within 5 days of injection, but has also been recorded within 12 hours with abobotulinumtoxinA. Duration of effect is more variable, and is influenced by parameters such as muscle mass (including the effects of age and sex) and type of product used. Even when larger muscles are treated with higher doses of BoNT-A, the duration of effect is still shorter than that for smaller muscles. Muscle injection technique, including dilution of the toxin, the volume of solution injected, and the positioning of the injections, can also have an important influence on onset and duration of activity. Comparison of the efficacy of different forms of BoNT-A must be made with the full understanding that the dosing units are not equivalent. Range of equivalence studies for abobotulinumtoxinA (Azzalure; Ipsen Limited, Slough UK/Galderma, Lausanne CH/Dysport, Ipsen Biopharm Limited, Wrexham UK/Galderma LP, Fort Worth, TX) and onabotulinumtoxinA (Botox; Allergan, Parsippany, NJ) have been conducted, and results indicate that the number of units of abobotulinumtoxinA needs to be approximately twice as high as that of onabotulinumtoxinA to achieve the same effect. An appreciation of the potential influence of all of the parameters that influence onset and duration of activity of BoNT-A, along with a thorough understanding of the anatomy of the face and potency of doses, are essential to tailoring treatment to individual patient needs and expectations.

Frozen versus fresh reconstituted botox for laryngeal dystonia

Objectives

To compare the efficacy and side effects of frozen versus fresh reconstituted botulinum toxin type A (BTX-A) in the treatment of laryngeal dystonia.

Study Design and Setting

Prospective open-label crossover study; 43 adult patients with adductor spasmodic dysphonia were randomly treated with fresh or refrozen reconstituted BTX-A at a private voice center. Treatment outcomes were assessed by duration of action and self-rated satisfaction (7 point Likert scale). Side effects of breathiness and dysphagia for liquids were assessed as well.

Results

There was no statistically significant difference in the duration of action (mean, 16.2 ± 8.5 vs 16.0 ± 7.6 weeks) and self-rated satisfaction of the treatment (median, 6.0 vs 6.0 points). The side effects were similar for both BTX-A injection types. In addition, there were no instances of infection for refrozen injections.

Conclusions

BTX-A may be safely used after being reconstituted and frozen or refrozen without a significant loss of effectiveness or additional side effects. In our experience, the period of freezing was on 2 occasions for up to 8 weeks.

Significance

Refrozen BTX-A may be a cost-effective use of an expensive drug. EBM rating: B-2b

Effects of botulinum toxin A injection on healing and tensile strength of ruptured rabbit Achilles tendons

BACKGROUND

Tendon lacerations are most commonly managed with surgical repair. Postoperative complications such as adhesions and ruptures often occur with immobilization. Early postoperative mobilization is therefore advised to minimize complications and time required to return to daily life. The aim of this study was to evaluate whether botulinum neurotoxin type-A (BoNT-A) can be used to enhance healing and prevent rupture in mobilized animals with Achilles tenotomy.

METHODS

Twenty-seven rabbits were divided into 3 groups, namely, I, II, and III, after surgical 1-sided Achilles tenotomy and end-to-end repair. The control group for biomechanical comparisons consisted of randomly selected contralateral (unoperated) healthy Achilles tendons. Group I received BoNT-A (4 U/kg) injection into the calf muscles. One week later, electromyographical confirmation was performed to establish the effects of injection. Surgery was then performed. Animals in the second group (n = 9, group II) were immobilized with a cast postoperatively. The third group (n = 9, group III) was mobilized immediately with no cast or BoNT-A. Tendons were harvested and gap formation or ruptures as well as strength of the repaired tendon were assessed 6 weeks after surgery.

RESULTS

Achilles tendons healed in all animals injected with BoNT-A, whereas all were ruptured in group III. All Achilles tendons of animals in groups I and II healed. However, group I repaired tendons were biomechanically equivalent to healthy tendons, whereas group II repaired tendons demonstrated significantly decreased tensile strength (P = 0.009).

CONCLUSIONS

The present study suggests that local injection of BoNT-A can be used for treatment of tendon rupture and may replace the use of cast for immobilization. However, further studies are needed to determine whether BoNT-A injection can have a beneficial effect on the healing of tendon repairs in humans.

The Inhibitory Effect of Platelet-Rich Plasma on Botulinum Toxin Type-A: An Experimental Study in Rabbits

BACKGROUND

Combination treatments of botulinum toxin type-A and other rejuvenation agents or instruments are gradually becoming more popular. After observing a high incidence of therapy failure following simultaneous applications of botulinum toxin type-A and platelet-rich plasma mesotherapy, we aimed to investigate whether PRP has an inhibitory effect on botulinum toxin type-A.

METHODS

Twenty-four New Zealand white rabbits were divided into 4 groups, and the anterior auricular muscle and overlying skin were used for injections. Groups I and II both received onabotulinumtoxinA intramuscular injections. In addition, autologous platelet-rich plasma mesotherapy was performed in Group I while Group II received saline mesotherapy. Group III was designed as the in vitro mixture group in which onabotulinumtoxinA and platelet-rich plasma were mixed and then administered intramuscularly. Group IV received saline within the mixture instead of platelet-rich plasma. The contralateral ears of all the rabbits served as control and were only treated with onabotulinumtoxinA. Visual evaluation of ear positions and electroneuromyographic studies were done prior to all procedures and at day 14. Anterior auricular muscles were harvested at day 14 and were evaluated with quantitative real-time PCR.

RESULTS

Visual and electroneuromyographic studies revealed less onabotulinumtoxinA activity in Groups I and III. When platelet-rich plasma was administered through skin mesotherapy, onabotulinumtoxinA activity failure was more severe in comparison with direct contact. No significant difference in SNAP-25 mRNA expression through quantitative real-time PCR was observed between groups.

CONCLUSION

Although we could not explain the exact mechanism underlying this interaction, platelet-rich plasma applications result in less onabotulinumtoxinA muscle paralysis activity.

Absence of bacterial or fungal growth in vials of reconstituted botulinum toxin type A after storage

BACKGROUND

Botulinum toxin type A (BTX-A; Botox) is supplied as individual freeze-dried preparations that should be administered within 24 hours after reconstitution. To avoid wasting this expensive drug, some physicians have resorted to storing vials of reconstituted BTX-A beyond the recommended duration. However, there is insufficient evidence to indicate that the sterility of previously reconstituted BTX-A is maintained during storage.

OBJECTIVES

The authors sought to determine whether bacterial and/or fungal proliferation occurred in vials of reconstituted BTX-A and subsequent storage of the remaining solution under refrigeration for 4 weeks.

METHODS

A portion of the contents of 88 consecutive 100-U vials of BTX-A was administered aseptically to 108 patients for essential blepharospasm, hemifacial spasm, or facial rejuvenation. The vials were then stored for 4 weeks in a refrigerator, after which the contents were transferred to various media (blood agar, chocolate agar, Sabouraud agar, brain-heart infusion medium, and thioglycolate broth) and assessed for bacterial and/or fungal growth by standard methods.

RESULTS

None of the BTX-A vials contained detectable bacterial or fungal contamination after 4 weeks of storage.

CONCLUSIONS

Storing vials of reconstituted BTX-A for 4 weeks after administration to patients was not associated with detectable growth of bacteria or fungi.

Cosmetic treatments: an emerging field of interest for interventional radiologists

The current trend in medical care in the 21st century is evolving into a minimally invasive specialty. The interest of Interventional Radiology (IR) in cosmetic is increasing particularly for outsetting patients, in the treatment of soft tissue vascular malformations, us-guided injections of Botox and varicous veins management. Advantages of cosmetic IR treatments are many: treatments takes less than an hour and provides immediate relief of symptoms; no scaring, because the procedure does not require a surgical incision; an immediate return to normal activity with little or no pain; and high success rate and low recurrence rate compared to surgery.

Influence of unilateral masseter muscle atrophy on craniofacial morphology in growing rabbits

PURPOSE

The purpose of the study was to evaluate whether the induction of unilateral masticatory muscle dysfunction can alter the skeletal growth patterns.

MATERIALS AND METHODS

Twenty-one white male New Zealand rabbits (4 weeks old) were divided into 3 groups of 7 subjects: group 1 served as the control to study normal craniofacial growth. In groups 2 and 3, rabbits were injected with 5 units and 15 units of Botulinum toxin A (BTXA) into the right masseter muscle, respectively. The effect of a neuromuscular blockade of masseteric activity on craniofacial growth was evaluated with 3 samples of serial computed tomography (CT) scans with a slice thickness of 0.625 mm, taken at 4 weeks (base line), 8 weeks (endpoint of prepubertal craniofacial growth), and 24 weeks (after pubertal growth).

RESULTS

The ipsilateral mandibular ramus height, zygomatic arch length, and masseteric length did not develop as much as those of the contralateral side after pubertal growth. At age 24 weeks, the masseter muscle volume asymmetry index reached -13.8% (group 2), -18.4% (group 3), and -1.6% for the control group. The ipsilateral side of the hemimandible showed less bone volume after 8 weeks but it showed partially recovered symmetry at 24 weeks. The maxillomandibular incisor midline and transverse molar discrepancies were not evident in any of the groups.

CONCLUSIONS

The BTXA injection can be an effective method in inducing site-specific muscular hypofunctions so that masticatory muscle-craniofacial bone interaction can be investigated efficiently. The result showed that the unilateral atrophy of the masseter muscle in the growing subjects influenced the morphology of the local skeletal sites. This did not, however, result ultimately in mandibular midline asymmetry or right-left asymmetry in hemimandibular volume after growth. The results imply that alterations in specific masticatory muscle function can be compensated by the growth of other structural components.

Effect of Fresh and Stored Botulinum Toxin A on Muscle and Nerve Ultrastructure

The aim of this study was to compare the ultrastructural alterations of the muscle and nerve that appear following injection of freshly reconstituted and stored botulinum toxin A. Fifteen New Zealand white rabbits were assigned to 6 groups, and anterior auricular muscle was used for injections. Group 1 did not receive any injection and group 2 received saline injection. Groups 3 and 5 received fresh botulinum; muscles and motor nerves were harvested at 5 days and 12 weeks, respectively. Groups 4 and 6 received stored botulinum; muscles and motor nerves were harvested at 5 days and 12 weeks, respectively. Alterations in muscle and nerve ultrastructure were evaluated with electron microscopy. Degeneration findings in muscle after botulinum toxin injection revealed no significant difference between freshly reconstituted and stored toxin in the early period. When stored toxin was used, atrophic changes in the muscle were less severe than the fresh toxin at 3 months. On nerve evaluation, fresh toxin displays significant acute changes on nerve ultrastructure; however, fresh and stored toxin shows similar degeneration at 12 weeks.

The use of Botox in interventional radiology

Botox (Botulinum toxin A) has wide public recognition as a cosmetic agent. It has also established a firm foothold within the medical community for the treatment of a wide range of myospastic disorders. With imaging guidance, interventional radiologists can deliver this medication to a variety of otherwise difficult to reach targets with high accuracy and with minimal complications. We illustrate the use of Botox in interventional radiology by describing our fluoroscopic technique for the treatment of piriformis syndrome. The key to successful Botox therapy of myospastic disorders is accurate clinical diagnosis. Excellent communication and rapport with the referring clinicians is therefore essential to maximize the likelihood of a successful outcome. The range of services offered by interventional radiologists continues to evolve. With the recent growth of endovenous treatment for varicose veins, some have found it necessary to provide sclerotherapy for spider veins. As patients become accustomed to receiving these cosmetic treatments from interventionalists, they may come to us for advice about other esthetic therapy. The idea of some interventional radiologists adding cosmetic medicine to their practice should, therefore, not seem unreasonable. We illustrate the use of Botox for facial rejuvenation by describing our technique for the treatment of glabelar (frown) lines. Before entering into this type of practice, it is critical to obtain adequate and appropriate training for each cosmetic intervention. If possible, the interventionalist should seek to establish a mentor relationship with someone highly experienced in cosmetic medicine.

Microbial growth in vials of Botulinum toxin following use in clinic

PURPOSE

Botulinum toxin has various applications in ophthalmology and is used in the outpatient department, where it is often exposed to room temperatures for 3-4 h. The manufacturer's recommendations are that the reconstituted toxin be stored in a refrigerator when not in use and discarded 4 h after reconstitution. The aim of our study was to examine such used bottles of Botulinum toxin for microbial growth after 4 h at room temperature.

METHODS AND RESULTS

Eleven consecutive bottles of Botulinum toxin used with aseptic precautions in the Ophthalmology outpatient clinics were exposed to room temperatures for 4 h. These were subsequently analysed for microbial growth. No growth was directly obtained from any of the Botulinum toxin bottles during our study.

CONCLUSIONS

This pilot study suggests that if aseptic precautions are followed during the use of Botulinum toxin, the contents of the bottle remain sterile despite being exposed to room temperatures for up to 4 h. This has implications on the use of the reconstituted toxin after the recommended 4 h.

Reduced potency after refrigerated storage of botulitum toxin A: Human extensor digitorum brevis muscle study

To determine whether the potency of botulinum toxin A (BTA) decreases after being reconstituted with normal saline and stored in refrigerator, we injected one side of the extensor digitorum brevis muscle with 2.5 units of botulinum toxin A that had been immediately reconstituted with saline, and the contralateral side with identical material that had been reconstituted and stored in a refrigerator for preselected periods (1, 2, and 4 weeks) in 32 healthy volunteers. Mean compound muscle action potential amplitudes expressed as a percentage of the baseline amplitude were more reduced in sides injected with immediately reconstituted BTA than in sides injected with BTA stored for 1 week or more (P < 0.05). No bacterial growth was observed in any stored BTA samples. Storage of reconstituted BTA at low temperatures may affect the potency of the toxin. Therefore, the use of BTA after refrigerated storage is not recommended.

Interaction of botulinum toxin type A with local anesthetic agents: an experimental study with rabbits

Injection of botulinum toxin is a painful procedure, limiting the number of patients treated. This study was designed to establish whether infiltration of local anesthetics plays a role in the effectiveness of botulinum toxin. For the study, 24 New Zealand white rabbits were divided into three groups. In all three groups, local anesthetics (prilocaine, lidocaine, lidocaine, and epinephrine) were injected into the right anterior auricular muscle before a 2.5-U injection of botox A. The contralateral anterior auricular muscle of all the rabbits was injected with the same dose of the toxin to serve as a control. Photographic documentation was recorded; electromyographic study was performed; and results were statistically analyzed. The results show that local anesthetics do not play a role in the efficacy of botulinum toxin. Thus, the use of infiltrative local anesthetics before botulinum toxin injection is a safe method for achieving a less painful procedure for the patient.