Botox: beyond wrinkles

Management of excessive gingival display using botulinum toxin type A: a descriptive study

Botulinum toxin is a protease used by the bacterium Clostridium botulinum that causes chemical denervation of skeletal muscles, producing a temporary weakening of muscle activity. Despite having a transitory effect, the application of botulinum toxin has been identified as an alternative for correcting an excessive gingival display (EGD). However, studies evaluating the maintenance of long-term results of botulinum toxin remain scarce. This study aimed to evaluate the effectiveness and duration of botulinum toxin type A in the treatment of anterior EGD. Botulinum toxin Type A was applied to 15 patients with EGD. The measurement was performed in triplicate, using a Castro Viejo dry point compass, between the central cervical portion of the upper lateral incisors to the lower portion of the upper lip, bilaterally. The measurements were performed before the application of the toxin and repeated on days 7, 14, 90, 120, and 180 after the procedure. The data were analyzed using repeated-measures ANOVA, followed by a Bonferroni. There was a statistically significant reduction between the measurements performed on the Baseline and seven days after the application of the botulinum toxin. After 180 days, approximately one-quarter of the patients in the sample did not presented EGD. Mild adverse effects were reported by 46.7% of the patients. The use of botulinum toxin type A was effective to treat EGD. After 180 days, it was still possible to observe a significant effect compared to the initial gingival exposure.

Botulinum Neurotoxin Diversity from a Gene-Centered View

Botulinum neurotoxins (BoNTs) rank amongst the most potent toxins known. The factors responsible for the emergence of the many known and yet unknown BoNT variants remain elusive. It also remains unclear why anaerobic bacteria that are widely distributed in our environment and normally do not pose a threat to humans, produce such deadly toxins. Even the possibility of accidental toxicity to humans has not been excluded. Here, I review the notion that BoNTs may have specifically evolved to target vertebrates. Considering the extremely complex molecular architecture of the toxins, which enables them to reach the bloodstream, to recognize and enter neurons, and to block neurotransmitter release, it seems highly unlikely that BoNT toxicity to vertebrates is a coincidence. The carcass⁻maggot cycle provides a plausible explanation for a natural role of the toxins: to enable mass reproduction of bacteria, spores, and toxins, using toxin-unaffected invertebrates, such as fly maggots, as the vectors. There is no clear correlation between toxigenicity and a selective advantage of clostridia in their natural habitat. Possibly, non-toxigenic strains profit from carcasses resulting from the action of toxigenic strains. Alternatively, a gene-centered view of toxin evolution would also explain this observation. Toxin-coding mobile genetic elements may have evolved as selfish genes, promoting their own propagation, similar to commensal viruses, using clostridia and other bacteria as the host. Research addressing the role of BoNTs in nature and the origin of toxin variability goes hand in hand with the identification of new toxin variants and the design of improved toxin variants for medical applications. These research directions may also reveal yet unknown natural antidotes against these extremely potent neurotoxins.

Frontal Alopecia after Repeated Botulinum Toxin Type A Injections for Forehead Wrinkles: An Underestimated Entity?

BACKGROUND

Injections of botulinum toxin type A in the forehead have never been reported to cause hair side effects.

OBJECTIVE

The aim of this paper is to report a new type of alopecia, which we have seen in women undergoing periodic injections of botulinum toxin type A for forehead wrinkles, and to differentiate it from other types of hair loss.

METHODS

We conducted an observational study on 5 females recruited from a private and an institutional practice who complained of progressive recession of the hairline after periodic injections of botulinum toxin type A in the forehead.

RESULTS

Alopecia of the frontal hairline was evident in all 5 patients, with absence of skin atrophy or scarring and progressive hair miniaturization at trichoscopy.

CONCLUSION

Dermatologists should be aware of the possible occurrence of frontal alopecia after repeated injections of botulinum toxin type A for forehead wrinkles.

Botulinum toxin type A induces changes in the chemical coding of substance P-immunoreactive dorsal root ganglia sensory neurons supplying the porcine urinary bladder

Botulinum toxin (BTX) is a potent neurotoxin which blocks acetylcholine release from nerve terminals, and therefore leads to cessation of somatic motor and/or parasympathetic transmission. Recently it has been found that BTX also interferes with sensory transmission, thus, the present study was aimed at investigating the neurochemical characterization of substance P-immunoreactive (SP-IR) bladder-projecting sensory neurons (BPSN) after the toxin treatment. Investigated neurons were visualized with retrograde tracing method and their chemical profile was disclosed with double-labelling immunohistochemistry using antibodies against SP, calcitonin gene-related peptide (CGRP), pituitary adenylate cyclase activating polypeptide (PACAP), neuronal nitric oxide synthase (nNOS), galanin (GAL), calbindin (CB), and somatostatin (SOM). In the control group (n = 6), 45% of the total population of BPSN were SP-IR. Nearly half of these neurons co-expressed PACAP or CGRP (45% and 35%, respectively), while co-localization of SP with GAL, nNOS, SOM or CB was found less frequently (3.7%, 1.8%, 1.2%, and 0.7%, respectively). In BTX-treated pigs (n = 6), toxin-injections caused a decrease in the number of SP-IR cells containing CGRP, SOM or CB (16.2%, 0.5%, and 0%, respectively) and a distinct increase in these nerve cells immunopositive to GAL (27.2%). The present study demonstrates that BTX significantly modifies the chemical phenotypes of SP-IR BPSN.

Changes in chemical coding of sympathetic chain ganglia (SChG) neurons supplying porcine urinary bladder after botulinum toxin (BTX) treatment

Botulinum toxin (BTX) is a neurotoxin used in medicine as an effective drug in experimental therapy of neurogenic urinary bladder disorders. We have investigated the influence of BTX on the chemical coding of sympathetic chain ganglia (SChG) neurons supplying the porcine urinary bladder. The toxin was injected into the wall of the bladder. SChG neurons were visualized by a retrograde tracing method with fluorescent tracer fast blue (FB) and their chemical coding was investigated by double-labelling immunohistochemistry with antibodies against dopamine β-hydroxylase (DβH; a marker of noradrenergic neurons), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), somatostatin (SOM), galanin (GAL), Leu(5)-enkephalin (L-ENK) and neuronal nitric oxide synthase (nNOS). In both the control (n = 5) and BTX-treated pigs (n = 5), the vast majority (91 ± 2.3 % and 89.8 ± 2.5 %, respectively) of FB-positive (FB+) nerve cells were DβH+. BTX injections caused a decrease in the number of FB+/DβH+ neurons that were immunopositive to NPY (39.5 ± 4.5 % vs 74.5 ± 11.9 %), VIP (8.9 ± 5.3 % vs 22.3 ± 8.8 %), SOM (5.8 ± 2.3 % vs 17.4 ± 3.7 %) or GAL (0.9 ± 1.2 % vs 5.4 ± 4.4 %) and a distinct increase in the number of FB+/DβH+ neurons that were immunoreactive to L-ENK (3.7 ± 2.9 % vs 1.1 % ± 0.8 %) or nNOS (7.7 ± 3.5 % vs 0.8 ± 0.6 %). Our study provides novel evidence that the therapeutic effects of BTX on the mammalian urinary bladder are partly mediated by SChG neurons.

Structural basis for recognition of synaptic vesicle protein 2C by botulinum neurotoxin A

Botulinum neurotoxin A (BoNT/A) belongs to the most dangerous class of bioweapons. Despite this, BoNT/A is used to treat a wide range of common medical conditions such as migraines and a variety of ocular motility and movement disorders. BoNT/A is probably best known for its use as an antiwrinkle agent in cosmetic applications (including Botox and Dysport). BoNT/A application causes long-lasting flaccid paralysis of muscles through inhibiting the release of the neurotransmitter acetylcholine by cleaving synaptosomal-associated protein 25 (SNAP-25) within presynaptic nerve terminals. Two types of BoNT/A receptor have been identified, both of which are required for BoNT/A toxicity and are therefore likely to cooperate with each other: gangliosides and members of the synaptic vesicle glycoprotein 2 (SV2) family, which are putative transporter proteins that are predicted to have 12 transmembrane domains, associate with the receptor-binding domain of the toxin. Recently, fibroblast growth factor receptor 3 (FGFR3) has also been reported to be a potential BoNT/A receptor. In SV2 proteins, the BoNT/A-binding site has been mapped to the luminal domain, but the molecular details of the interaction between BoNT/A and SV2 are unknown. Here we determined the high-resolution crystal structure of the BoNT/A receptor-binding domain (BoNT/A-RBD) in complex with the SV2C luminal domain (SV2C-LD). SV2C-LD consists of a right-handed, quadrilateral β-helix that associates with BoNT/A-RBD mainly through backbone-to-backbone interactions at open β-strand edges, in a manner that resembles the inter-strand interactions in amyloid structures. Competition experiments identified a peptide that inhibits the formation of the complex. Our findings provide a strong platform for the development of novel antitoxin agents and for the rational design of BoNT/A variants with improved therapeutic properties.

Balanced botox chemodenervation of the upper face: symmetry in motion

Cosmetic botulinum toxin type A (Botox, Allergan, Inc., Irvine, CA) has revolutionized minimally invasive treatment of the upper face. Increasingly sophisticated outcomes result in facial symmetry in motion. The face is a three-dimensional moving unit, not an isolated photograph. This is why the advanced injector must hone an astute ability to observe casual microexpressions. Consideration is then given to the patient's age, facial anatomy, facial asymmetry, and dynamic rhytids. The ratio of dosing to agonist and antagonist muscles that allows unopposed action is determined. Nuance in placement and dose combined with adjunct therapy results in natural and appropriate facial emotion and avoids unnatural or bizarre patterns of movement. Asymmetrical scenarios are presented to exemplify this process of analysis and treatment. Many authors have detailed the mechanism of action, history of Botox development, and specific muscle group treatment in the periorbital region. In this discussion, I leave behind rigorous academic analysis and wish to offer my approach, which has evolved through 15 years experience treating the aesthetic patient with Botox. The clinician can read about recommended patterns of injection, and the procedure is quite simple. It is only through skilled observation and understanding of expressive nuance and anatomy that the advanced injector will meet the goal of a natural communicative result with chemodenervation. Experience is accumulated through critical analysis of patient results over time. This discussion first directs attention to why it is important to learn how to look at the face in motion as well as at facial rhytids. A plan is developed for treatment including drug preparation, dosing decisions, precise three-dimensional delivery, and adjunct therapy. Perils may generally be avoided by choosing appropriate dosing and placement. The asymmetrical patient scenario is used to demonstrate nuance in evaluation and treatment.

Comparing two botulinum toxin type A formulations using manufacturers? product summaries

BACKGROUND AND OBJECTIVE

Because of the unique pharmacology and clinical versatility of botulinum toxin (BoNT), particularly BoNT serotype A (BoNTA), a need exists for discussion of the current data on similarities and differences between two BoNTA products, BOTOX and Dysport.

METHODS

We compared the physiochemical and pharmacological properties of BOTOX and Dysport using information from the Summary of Product Characteristics (SmPC) documents from a number of countries around the world.

RESULTS AND DISCUSSION

Our analysis based on the SmPC documents demonstrated distinct differences in physical characteristics, breadth of approved indications, dosing and administration, and the incidence and severity of adverse events.

CONCLUSION

BOTOX and Dysport are not bioequivalent. Many of the differences between BOTOX and Dysport discussed within are probably related to the differences in their physical characteristics.

Postherpetic Neuralgia in Older Adults

The purpose of this article is to describe current knowledge and standards of care for postherpetic neuralgia (PHN) among older persons. Three influencing factors are considered: cultural implications, quality of life (QOL), and current practice of alternative/complementary therapy. A review of literature published between 2001 and 2006 was conducted. The findings indicate that PHN has debilitating effects on older adults regardless of culture. The impact of PHN on culture and ethnicity, particularly on the relationship between culture and patient's self-report of herpes zoster and/or PHN, has not been well investigated as evidenced in the literature. PHN is found to be associated with decreased health-related QOL among the elderly, with the most affected domains being sleep, mood, and general activity. Alternative and complementary therapy offers many advantages such as ease of use, availability, and low cost. However, due to lack of controlled trials and insufficient evidence, alternative therapy is not currently used widely and recommended. As the US population ages, the incidence of herpes zoster and PHN is expected to rise. Clinical trials that explore the response of the culturally diverse older adults to current treatment guidelines, strategies for prevention of PHN and its corresponding decrease in QOL, as well as controlled trials of alternative/complementary remedies should be considered.

Combination therapy with BOTOXtm and fillers: the new rejuvnation paradigm

Until relatively recently, restoration of appearance by replacement of lost facial volume and muscular relaxation has been an illusory goal. With advances in the commercial availability of newer filling agents and a better understanding of the clinical esthetic effects of botulinum toxin A, remarkably sophisticated and refined results can now be achieved by using these noninvasive techniques. The combined use of BTX-A and filling agents, such as collagen and hyaluronic acid, can restore facial appearance by the dual mechanisms of reflation and relaxation. In addition, their combined use appears to increase the longevity of tissue dwell time of the filling agent. Current practices now strive to correct wrinkles by restoring volume and also relaxing the pull of muscles that create negative facial expressions such as glabellar folds, mouth frown, crow's feet, horizontal forehead lines, and perioral and cervical rhytides. As with any of the new technological innovations currently available, understanding of the differing properties of the agents used and education in optimal technique is essential to clinical and esthetic success.

The analgesic potential of clostridial neurotoxin derivatives

Botulinum neurotoxins are the most potent acute lethal toxins known, and yet for the last two decades they, and in particular serotype A, have found increasing use in the clinical treatment of diseases or conditions involving neuromuscular or autonomic neuronal transmission. The neurotoxins work by inhibiting the release of acetylcholine from peripheral cholinergic nerve terminals. More recently, the effects on non-cholinergic pathways have been identified, and this has led to an increase in the diseases and syndromes for which botulinum neurotoxins have been found to have clinical utility. In particular, botulinum neurotoxins have been demonstrated to potentially benefit a range of chronic pain syndromes. With the description in the last decade of the biochemical basis of neurotoxin action and the tertiary structure of the toxin molecule, the possibility of designing novel agents utilising selected aspects of toxin function has arisen. This possibility has been pursued in the context of pain relief with the description of a novel hybrid protein derived from botulinum neurotoxin type A, LH(N)/A-ECL, able to selectively target nociceptive afferent neurons and inhibit the release of neurotransmitters involved in pain transmission. This novel derivative of botulinum neurotoxin type A demonstrates prolonged analgesic activity in vivo. This review will consider the evidence for the analgesic properties of the botulinum neurotoxins and their suitability as the basis for novel therapeutic proteins. The general concept of deriving novel therapeutic molecules from the neurotoxins will also be considered.

A new wrinkle on pain relief: re-engineering clostridial neurotoxins for analgesics

Botulinum neurotoxins are used to treat of a range of chronic neuromuscular conditions and, increasingly, conditions involving non-neuromuscular transmission, both cholinergic and non-cholinergic, including chronic pain. However, their clinical use is limited by the potential for adverse effects related to the neuromuscular activity, which results from the selectivity of the toxin for the neuromuscular junction. The elucidation of the structure of the botulinum toxin molecule and its relationship to neurotoxin function has enabled the design of novel molecules incorporating selected aspects of toxin function. This review considers the suitability of engineered neurotoxins as the basis for novel therapeutic proteins and the opportunity of developing analgesics based on these neurotoxins.