Resolution of Two Steps in Botulinum Neurotoxin Serotype A1 Light Chain Localization to the Intracellular Plasma Membrane.

Botulinum neurotoxin serotype A (BoNT/A) is the most potent protein toxin to humans. BoNT/A light chain (LC/A) cleavage of the membrane-bound SNAP-25 has been well-characterized, but how LC/A traffics to the plasma membrane to target SNAP-25 is unknown. Of the eight BoNT/A subtypes (A1-A8), LC/A3 has a unique short duration of action and low potency that correlate to the intracellular steady state of LC/A, where LC/A1 is associated with the plasma membrane and LC/A3 is present in the cytosol. Steady-state and live imaging of LC/A3-A1 chimeras identified a two-step process where the LC/A N terminus bound intracellular vesicles, which facilitated an internal α-helical-rich domain to mediate LC/A plasma membrane association. The propensity of LC/A variants for membrane association correlated with enhanced BoNT/A potency. Understanding the basis for light chain intracellular localization provides insight to mechanisms underlying BoNT/A potency, which can be extended to applications as a human therapy.

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.

The Effect of Albumin and Platelet-Poor Plasma Supplemented Botulinum A Toxin on Bioavaliability: An Experimental Rabbit Model.

Today, botulinum toxin is commonly used for cosmetic purposes throughout the world. Despite various agents reducing the efficiency of toxin are well defined, the studies related to increasing the bioavailability are limited. The purpose of our study is to assess the effect of the preparation of toxin by diluting with platelet-poor plasma (PPP) and/or albumin instead of standard dilution (saline) on bioavailability in cosmetic-purpose botulinum toxin applications.In the study, 24 New Zealand rabbits were used. Right anterior auricular muscle was preferred for toxin injections. Subjects were divided in 4 groups and in every group; botulinum A toxin (BTxA) that was prepared by different dilution methods was injected. 2.5 U saline-diluted BTxA was injected to the subjects in group 1, 2.5 U ready-to-use rabbit albumin-diluted BTxA was injected to group 2 and 2.5 U autologous PPP-diluted BTxA was injected to group 3 and pure saline was injected to group 4.Before the injection (0th week) and in the second, sixth, and 12th weeks after the injection, visual and electroneuromyographic evaluations of the ears of the subjects were performed.In the second week, median amplitude levels in group 2 were significantly found lower than other groups.In the sixth week, median amplitude levels in group 1 were significantly found lower than other groups.In 12th week, no significant difference was found among all the groups in terms of median amplitude levels.Visual findings were also correlated with electroneuromyographic findings.It was observed that the dilution of BTxA with albumin had caused a stronger paralysis when compared to dilution with saline or PPP at the beginning (second week); however, in the following weeks (sixth week), it was seen that dilution with saline had maintained paralysis better when compared with other dilution methods.In cosmetic BTxA applications, dilution of the toxin with albumin or PPP instead of standard dilution has no positive effect on bioavailability and such modifications regarding this kind of dilution are found unsuitable. Further studies are needed to directly relate the results with clinical applications.

A Randomized, Double-Blind Trial to Investigate the Equivalence of IncobotulinumtoxinA and OnabotulinumtoxinA for Glabellar Frown Lines.

BACKGROUND: IncobotulinumtoxinA and onabotulinumtoxinA are indicated for the temporary improvement in the appearance of glabellar frown lines (GFL). This is the first randomized direct comparator study to date, at the Food and Drug Administration-recommended dose of 20 units (U), for the treatment of GFL. OBJECTIVE: To investigate the dose equivalence of incobotulinumtoxinA (20 U) and onabotulinumtoxinA (20 U) for the treatment of moderate-to-severe GFL. MATERIALS AND METHODS: Prospective, randomized (1:1), double-blinded, parallel-group study in 250 females (18-50 years), employing a single treatment with incobotulinumtoxinA or onabotulinumtoxinA, followed by a 4-month observational period. RESULTS: At the primary efficacy endpoint (1 month after treatment), incobotulinumtoxinA was equivalent to onabotulinumtoxinA in the treatment of GFL at the 20 U dose within the prespecified ± 15% margin of equivalence. Efficacy remained similar between treatment groups through 4 months after treatment as assessed by the independent masked panel and the masked treating physicians. Patient satisfaction ratings were similar between groups and favorable (>90%) throughout. Both treatments were well tolerated. CONCLUSION: Equivalence was demonstrated at the primary endpoint between incobotulinumtoxinA and onabotulinumtoxinA in the treatment of GFL at the 20 U dose at 1 month. Similar efficacy and tolerability profiles were observed through 4 months after treatment.

Delayed contrast-enhanced MRI to localize Botox after cystoscopic intravesical injection.

PURPOSE: There is a lack of studies to show localization of botulinum toxins (BoNT) within bladder wall and/or absorption rates. Our study examined the later distribution of BoNTA/gadolinium within the bladder wall by performing a delayed MRI scan after intravesical injection. This potentially may help to explain the level and mechanism at which BoNT may be producing its effect. METHODS: A prospective study enrolled 20 consecutive patients with neuropathic or idiopathic overactive bladders. The Aim of the study was to perform MRI 3 h post procedure. Botox 100-200 IU was reconstituted with 19 ml saline and 1 ml of gadolinium contrast. Intradetrusor injections were administered using a rigid 21F cystoscope with a total of 20 injections into bladder wall, including two into the trigone. The depth of injection was approximately 2 mm, without raising a bleb. One radiologist reviewed films and reported on the number of bladder walls with contrast, location, the presence of extravesical extravasation, contrast in distal ureter(s), and bladder wall thickness. RESULTS: Ninety percentage of patients had contrast within bladder wall. There was a variation in the number of bladder walls involved; 85 % had contrast seen in at least two walls. Also, a variation was noted in the extent of extravasation; 80 % showed some evidence. CONCLUSIONS: Diffusion of BoNT after intravesical injection is very common once bladder wall is breeched. Precise injection localization into muscle layer may not be as relevant to outcome as previously assumed. The assumption in our study that localization and diffusion of contrast also represents the localization of BoNT is open to critique as BoNT diffusion is potentially slower (Mehnert et al. in World J Urol 27(3):397-403, 2009). The absence of systemic symptoms after the injection in our series supports guidelines concerning the safety of procedure.

Diffusion of two botulinum toxins type A on the forehead: double-blinded, randomized, controlled study.

BACKGROUND: Different diffusion of different botulinum toxin type A (BoNTA) preparations may account for differences in outcomes in cosmetic clinical practice. OBJECTIVES: A double-blind, randomized, self-controlled study was performed to evaluate the diffusion characteristics of onabotulinumtoxinA and a Chinese type A botulinum toxin (CBTX-A). MATERIALS AND METHODS: Healthy volunteers (N = 20) were recruited to receive a 0.05-mL (2 U) injection of BoTNA at four forehead sites (medial forehead (subcutaneous (SC)) and temporal forehead (intradermal (ID))). On day 14, the Minor's iodine starch test was performed and photographs were taken for calculating the area and dimensions of anhydrotic area. RESULTS: When BoNTAs were different, the anhidrosis ID area was significantly greater with CBTX-A than onabotulinumtoxinA, the vertical dimension was significantly longer with CBTX-A ID than onabotulinumtoxinA ID and the horizontal dimension was significantly greater with CBTX-A ID than onabotulinumtoxinA ID. The area of anhidrosis SC was significantly greater with CBTX-A than onabotulinumtoxinA. When injection depths were different, the mean horizontal dimension was significantly greater with onabotulinumtoxinA SC than ID. Comparing the dimension of the same BoNTA and injection method, the vertical dimension was significantly greater than the horizontal dimension. CONCLUSION: OnabotulinumtoxinA diffuses less than CBTX-A. ID injection technique may result in less diffusion than SC.

Analysis of the mechanisms that underlie absorption of botulinum toxin by the inhalation route.

Botulinum toxin is a highly potent oral and inhalation poison, which means that the toxin must have an efficient mechanism for penetration of epithelial barriers. To date, three models for toxin passage across epithelial barriers have been proposed: (i) the toxin itself undergoes binding and transcytosis; (ii) an auxiliary protein, HA35, transports toxin from the apical to the basal side of epithelial cells; and (iii) an auxiliary protein, HA35, acts on the basal side of epithelial cells to disrupt tight junctions, and this permits paracellular flux of toxin. These models were evaluated by studying toxin absorption following inhalation exposure in mice. Three types of experiments were conducted. In the first, the potency of pure neurotoxin was compared with that of progenitor toxin complex, which contains HA35. The results showed that the rate and extent of toxin absorption, as well as the potency of absorbed toxin, did not depend upon, nor were they enhanced by, the presence of HA35. In the second type of experiment, the potencies of pure neurotoxin and progenitor toxin complex were compared in the absence or presence of antibodies on the apical side of epithelial cells. Antibodies directed against the neurotoxin protected against challenge, but antibodies against HA35 did not. In the final type of experiment, the potency of pure neurotoxin and toxin complex was compared in animals pretreated to deliver antibodies to the basal side of epithelial cells. Once again, antibodies directed against the neurotoxin provided resistance to challenge, but antibodies directed against HA35 did not. Taken collectively, the data indicate that the toxin by itself is capable of crossing epithelial barriers. The data do not support any hypothesis in which HA35 is essential for toxin penetration of epithelial barriers.

Split-face double-blind study comparing the onset of action of onabotulinumtoxinA and abobotulinumtoxinA.

OBJECTIVE: To report and discuss the outcome of a prospective, internally controlled, randomized, double-blind, split-face study comparing the onset of action of 2 commercially available botulinum neuromodulators. METHODS: Ninety individuals with moderate-to-severe lateral orbital rhytids were treated with onabotulinumtoxinA, 10 U, and abobotulinumtoxinA, 30 U, for the treatment of lateral orbital rhytids. Participants were assessed live with a validated 5-point photographic scale before treatment and on days 2, 4, and 6 after treatment. Photographs were taken at each encounter. Statistical analysis was applied to evaluate for any significant difference in onset of action between the 2 products. RESULTS: AbobotulinumtoxinA and onabotulinumtoxinA demonstrated statistically significant change from baseline at day 2 in the treatment of lateral orbital rhytids at maximal contraction and rest when evaluated independently by investigator and participant (P.001). Also at day 2, the improvement with abobotulinumtoxinA was better than that with onabotulinumtoxinA for the primary end point of maximal contraction graded by the investigator, although this did not reach statistical significance (P=.21); by day 4, the greater improvement achieved with abobotulinumtoxinA reached statistical significance (P=.02) and remained superior at day 6 (P=.02). The primary findings were strengthened by similar results in the secondary end points of patient self-grade at maximal contraction and at rest and of investigator grade at rest. CONCLUSIONS: In conclusion, both abobotulinumtoxinA and onabotulinumtoxinA achieved statistically significant onset of action at day 2. This improvement was seen in all end points, with abobotulinumtoxinA demonstrating a trend toward greater improvement than onabotulinumtoxinA at day 2 and a statistically significant greater improvement at days 4 and 6 when looking at maximal contraction.

Botulinum neurotoxin subtype A2 enters neuronal cells faster than subtype A1.

Botulinum neurotoxins (BoNTs), the causative agent of human botulism, are the most potent naturally occurring toxins known. BoNT/A1, the most studied BoNT, is also used as an important biopharmaceutical. In this study, the biological activity of BoNT/A1 is compared to that of BoNT/A2 using neuronal cell models. The data obtained indicate faster and increased intoxication of neuronal cells by BoNT/A2 than BoNT/A1, and that the mechanism underlying this increased toxicity is faster and more efficient cell entry that is independent of ganglioside binding. These results have important implications for the development of new BoNT based therapeutics and BoNT countermeasures.

The science and manufacturing behind botulinum neurotoxin type A-ABO in clinical use.

BACKGROUND: Since the first comprehensive description of the physiologic effects of botulism toxicity in the 1820s, specific formulations of botulinum neurotoxin type A (BoNT-A) have been developed. Now, a new botulinum neurotoxin type A formulation (BoNTA-ABO; Dysport [abobotulinumtoxinA]; Medicis Aesthetics, Scottsdale, AZ) has been made available in the United States and these same physiologic effects have become beneficial clinical targets. This formulation has been used successfully for nearly 20 years in Europe and other countries under the trade name Dysport (Clostridium botulinum type A toxin-hemagglutinin complex; Ipsen Biopharm, Wrexham, UK). BoNT-A injections are administered to achieve temporary local flaccid paralysis of targeted muscles. Injection of BoNT-A formulations for aesthetic purposes was by far the most common minimally-invasive (nonsurgical) cosmetic procedure performed in the United States in 2008. OBJECTIVE: The objective of this review is to describe the latest data regarding the mechanism of action of BoNTA-ABO, the potential roles of neurotoxin-associated proteins (NAP), the manufacturing standards for these biologic products, and the specific manufacturing process and characteristics of BoNTA-ABO. METHODS: A systematic search using the US National Library of Medicine PubMed database was performed and the relevant articles were reviewed. Direct input and data from the worldwide manufacturer of Dysport have been included. RESULTS: The four sequential steps in the mechanism of action of BoNTA-ABO are binding, internalization, translocation, and intracellular proteolysis of the target protein. Although all BoNT-A products must meet standards for quality, potency, and safety, they should not be considered equivalent formulations because they have different production strains of the bacterium C botulinum, as well as different isolation and manufacturing processes that result in unique product characteristics. The production steps for Dysport-including a unique proprietary purification process using column chromatography and a unique proprietary finishing process-result in consistent and unique product features. Studies confirm that Dysport has a high degree of long-term batch-to-batch consistency for a range of specified properties, including specific potency, protein composition, toxin complex charge-density properties, and endopeptidase activity. In the native, natural form, NAP protect the endogenous neurotoxin from degradation in the acidic environment of the stomach; in biologic formulations, they may have effects on the structural stability, binding, uptake, and transcytosis of BoNT-A products in other areas of the body. NAP are most likely to stabilize the neurotoxin in a vial of clinical product. CONCLUSIONS: A thorough understanding of the mechanism of action, product characteristics, and effects of NAP is important to ensure appropriate and safe clinical use of BoNT-A products. Now approved in the United States, Dysport is an important addition to the group of available BoNT-A formulations.

Transport molecules using reverse sequence HIV-Tat polypeptides: not just any old Tat? (WO200808225).

BACKGROUND: Many polycationic cell penetrating peptides (CPPs), alternatively named protein transduction domains, have been used for the efficient intracellular delivery of biologically active agents. Patent WO2008/082885 relates to the properties and proposed biomedical applications of a CPP and putative-related sequences that represent the reverse sequence of a nonapeptide basic domain of the HIV-transactivator protein (Tat) (RRRQRRKKR). OBJECTIVE: This evaluation critically assesses the reported utility of such transport molecules and the numerous potential embodiments of the invention, in comparison with other recent developments in the field. We also review recent biomedical applications of Tat-derived peptide transporters. METHODS: The scope of this review includes both Tat-derived peptide transporters and other sequence-related CPPs that are polycationic in nature. RESULTS/CONCLUSION: The patent application indicates that reverse sequence HIV-Tat polypeptides can increase the transdermal delivery of an iodinated mixture of botulinum toxin, albumin and accessory proteins (Neuronox), Medy-Tox, Inc., Seoul, South Korea) as a non-covalent complex. Moreover, the invention also contemplates all variants of the reverse-sequence polypeptide and claims a variety of potential biomedical applications using the reverse sequence peptide as a delivery vector. Unfortunately, in the absence of both rigorous comparative data and toxicological analyses, it is uncertain if these transport molecules offer any advantages compared with many existing and rigorously characterised CPP vector systems.

Expression, purification and transduction of PEP-1-botulinum neurotoxin type A (PEP-1-BoNT/A) into skin.

Botulinum neurotoxin A (BoNT/A) has been used therapeutically to treat muscular hypercontractions and sudomotor hyperactivity and it has been reported that BoNT/A might have analgesic properties in headache. PEP-1 peptide is a known carrier peptide that delivers full-length native proteins in vitro and in vivo. In this study, a BoNT/A gene were fused with PEP-1 peptide in a bacterial expression vector to produce a genetic in-frame PEP-1-BoNT/A fusion protein. The expressed and purified PEP-1-BoNT/A fusion proteins were efficiently transduced into cells in a time- and dose-dependent manner when added exogenously in a culture medium. In addition, immunohistochemical analysis revealed that PEP-1-BoNT/A fusion protein efficiently penetrated into the epidermis as well as the dermis of the subcutaneous layer, when sprayed on mice skin. These results suggest that PEP-1-BoNT/A fusion protein provide an efficient strategy for therapeutic delivery in various human diseases related to this protein.

Botulinum toxin type B (MYOBLOC) versus botulinum toxin type A (BOTOX) frontalis study: rate of onset and radius of diffusion.

BACKGROUND: Botulinum toxin types A and B can improve the appearance of facial wrinkles. Differences in the time until onset and the degree of diffusion have been observed anecdotally, but no direct comparative studies have been done. OBJECTIVE: To compare the rate of onset and the radius of diffusion of botulinum toxin types A and B in the rhytides of the forehead. METHODS: Adults with symmetrical moderate to severe forehead wrinkles at full contracture received botulinum toxin type A (BOTOX; 5 U) on one side of the forehead and type B (MYOBLOC; 500 U) on the other side. Photographs taken at rest and full frontalis contracture were analyzed by computer, and a time-lapse motion picture was created. Radius of diffusion and time until full effect were measured. RESULTS: Botulinum toxin type B had a slightly faster onset of action than type A. All patients responded to type B quickly, whereas some had a delayed response to type A. A greater radius of diffusion was consistently observed with botulinum toxin type B, as measured by the greater area of wrinkle reduction at the doses used. CONCLUSIONS: In this comparative study of patients with symmetrical forehead wrinkles, botulinum toxin type B produced a greater area of diffusion and a more rapid onset of action than type A.

Diffusion and short-term efficacy of botulinum toxin A after the addition of hyaluronidase and its possible application for the treatment of axillary hyperhidrosis.

BACKGROUND: Botulinum toxin adequately treats hyperkinetic facial lines and hyperhidrosis. Higher doses of botulinum toxin appear to enhance efficacy and longevity possibly through greater evenness of diffusion; however, recurrent treatments with higher doses are expensive. OBJECTIVE: To admix botulinum toxin with hyaluronidase and to test whether there is maintenance of efficacy, a spread of effect, and possibly a decrease in required dose compared with botulinum toxin. METHODS: Six patients participated in a double-blinded side-to-side comparison pilot study with photographic analysis for frontalis overactivity and Minor's iodine and gravimetric testing for axillary hyperhidrosis. RESULTS: Initial efficacy of botulinum with admixed hyaluronic acid appeared maintained with possibly increased diffusion when hyaluronic acid is added. No difference was evident on short-term review of patients treated with 50 U of botulinum in one axilla compared with the contralateral side injected with 25 U with admixed hyaluronidase. CONCLUSION: There may be a role for hyaluronic acid in aiding diffusion and decreasing the required dose of botulinum toxin in hyperhidrosis axillaris.

Type A botulinum toxin: a new treatment for axillary and palmar hyperhidrosis.

Hyperhidrosis is an invalidating condition, and one that is difficult to treat. It is characterized by an excessive and uncontrolled production of sweat by the sweat glands, often causing psychological, social, and occupational problems for the patient. Hyperhidrosis can be distinguished in two forms: idiopathic (of unknown etiology), or secondary, due to an alteration of the endocrine system (ex: hyperthyroidism, neuropathy, neoplasia etc.) It is found in about 0.3-0.5% of the population and can be localized (axillary, palmar, plantar, facial) or diffused. The subcutaneous injection of type A botulinum toxin, until now used only for the treatment of blepharospasm or hemifacial spasm, has shown to be a useful treatment for localized hyperhidrosis. The objective of the authors is to evaluate the therapeutic efficacy, safety, and management of botulinum toxin treatment in patients affected with axillary or palmar hyperhidrosis resistant to conventional therapies.

Botulinum toxin A and facial lines: the variable concentration.

Our improved understanding of the functional anatomy of the face and of the action of the botulinum toxin A leads us to determine a new injection procedure which consequently decreases the risk of eyebrow and eyelid ptosis, and increases the toxin injection's possibilities and efficiencies. Variable toxin injection concentrations adapted to each injected area are used. Thanks to the new procedure in the upper face, toxin A action is quite close to an endoscopic surgical action. In addition, interesting results are achievable on the nose, upper part of the nasolabial fold, jawline and neck regions. Lastly, a smoothing effect on the skin is obtained by the anticholinergic action of the toxin A on the dermal receptors.

Toxina botulínica: una nueva alternativa / Botulinum toxin: a new alternative

La Toxina Botulínica (BOTOX) es un potente agente bloqueante que ha demostrado su gran utilidad en una amplia variedad de desórdenes neuromusculares asociados con hipertonía y espasticidad. Dicha toxina, y especialmente el serotipo A, también ha sido reconocida como beneficiosa en la corrección de arrugas faciales del tercio superior de la cara, siendo aprobado su uso médico por la FDA de los Estados Unidos desde 1979. Se ha comprobado que su acción es producida por una denervación química a nivel de la placa neuromuscular; dicho efecto es temporario (neurogénesis) y selectivo (para un músculo determinado). Aún siendo los riesgos despreciables, es aconsejable que el BOTOX sea administrado por médicos, quienes tengan un conocimiento profundo de la anatomía regional, fisiología y efectos clínicos de la toxina así como sus limitaciones y complicaciones