The potential effect of botulinum toxin type A on human dermal fibroblasts: an in vitro study

Investigating the impact of botulinum toxin type a on the migration of normal human dermal fibroblasts: An in vitro wound healing assay

BACKGROUND

Botulinum toxin A (BoNT-A) is widely utilized in the management of hypertrophic and keloid scars. One proposed mechanism for scar prevention involves the inhibition of fibroblast migration in scars by BoNT-A. However, the data regarding the effect of BoNT-A on the migration of normal human dermal fibroblasts (NHDF) is limited.

OBJECTIVES

The aim of this study was to investigate the inhibitory effect of different types and dilutions of BoNT-A on the migration of NHDF.

METHODS

In vitro scratch wound assay, NHDF cells were cultured, incubated, and subjected to scratching using a sterile tip. Subsequently, the scratched NHDF monolayer was treated with different types of BoNT-A, including onabotulinumtoxinA (ONA), incobotulinumtoxinA (INCO), prabotulinumtoxinA (PRABO), or letibotulinumtoxinA (LETI), at varying concentrations of 10, 20, 25, 40, 50, and 100 units/milliliter (U/mL). Additionally, abobotulinumtoxinA (ABO) was administered at concentrations of 33, 50, 66, 71, 100, 150, 300, and 500 U/mL. Normal saline solution (NSS) served as a negative control. The extent of NHDF migration was evaluated by comparing each dilution of BoNT-A with the controls using high-content imaging at the 48-h time point. Furthermore, the viability of the of NHDF was assessed.

RESULTS

The concentrations of 25, 40, and 50 U/mL of ONA (p < 0.001) and 25 U/mL of LETI (p < 0.05) demonstrated significantly inhibited NHDF migration in comparison to the control group. Conversely, all dilutions of PRABO, INCO, and ABO exhibited comparable NHDF migration to that of the control group. Regarding NHDF viability, no significant decrease was observed across any of the BoNT-A types and dilutions.

CONCLUSION

Different types and dilutions of BoNT-A demonstrated variable inhibitory effects on NHDF migration in vitro. The selection of BoNT-A formulation may significantly impact the clinical outcome of scar prevention related to fibroblast migration.

Evaluation of the Effect of Botulinum Toxin A on the Lymphatic Endothelial Cells

INTRODUCTION

Botulinum toxin A (BoTA) is a neurotoxin formed by Clostridium botulinum, with a broad medical application spectrum. While the primary effect of BoTA is on the muscles, the effects of BoTA in other systems including the blood vasculature have already been examined, revealing unexpected actions. However, no studies exist to the best of our knowledge regarding the potential effects of BoTA on the lymphatic vascular system, possessing a critical role in health and disease. Isolated human lymphatic endothelial cells (LECs) were cultured in dedicated in vitro culture systems. The analysis including imaging and cell culture approaches as well as molecular biology techniques is performed to examine the LEC alterations occurring upon exposure to different concentrations of BoTA.

MATERIALS AND METHODS

Human LECs were cultured and expanded on collagen-coated petri dishes using endothelial basal medium and the commercial product Botox from Allergan as used for all our experiments. Harvested cells were used in various in vitro functional tests to assess the morphologic and functional properties of the BoTA-treated LECs. Gene expression analysis was performed to assess the most important lymphatic system-related genes and pathways.

RESULTS

Concentrations of 1, 5 or 10 U of BoTA did not demonstrate a significant effect regarding the proliferation and migration capacity of the LECs versus untreated controls. Interestingly, even the smallest BoTA dose was found to significantly decrease the cord-like-structure formation capacity of the seeded LECs. Gene expression analysis was used to underpin possible molecular alterations, suggesting no significant effect of BoTA in the modification of gene expression versus the starvation medium control.

CONCLUSION

LECs appear largely unaffected to BoTA treatment, with an isolated effect on the cord-like-structure formation capacity. Further work needs to assess the effect of BoTA on the smooth-muscle-cell-covered collecting lymphatic vessels and the possible aesthetic implications of such an effect, due to edema formation.

LEVEL OF EVIDENCE V

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 .

Botox (onabotulinumtoxinA) mechanism of action

Studies in the 1920s found that botulinum neurotoxin type A (BoNT/A) inhibited the activity of motor and parasympathetic nerve endings, confirmed several decades later to be due to decreased acetylcholine release. The 1970s were marked by studies of cellular mechanisms aided by use of neutralizing antibodies as pharmacologic tools: BoNT/A disappeared from accessibility to neutralizing antibodies within minutes, although it took several hours for onset of muscle weakness. The multi-step mechanism was experimentally confirmed and is now recognized to consist broadly of binding to nerve terminals, internalization, and lysis or cleavage of a protein (SNAP-25: synaptosomal associated protein-25 kDa) that is part of the SNARE (Soluble NSF Attachment protein REceptor) complex needed for synaptic vesicle docking and fusion. Clinical use of the BoNT/A product onabotulinumtoxinA was based on its ability to reduce muscle contractions via inhibition of acetylcholine from motor terminals. Sensory mechanisms of onabotulinumtoxinA have now been identified, supporting its successful treatment of chronic migraine and urgency in overactive bladder. Exploration into migraine mechanisms led to anatomical studies documenting pain fibers that send axons through sutures of the skull to outside the head-a potential route by which extracranial injections could affect intracranial processes. Several clinical studies have also identified benefits of onabotulinumtoxinA in major depression, which have been attributed to central responses induced by feedback from facial muscle and skin movement. Overall, the history of BoNT/A is distinguished by basic science studies that stimulated clinical use and, conversely, clinical observations that spurred basic research into novel mechanisms of action.

Botulinum neurotoxins: Future innovations

Botulinum neurotoxins (BoNTs) are multi-domain proteins whose potent and selective actions on nerve endings have led to innovations in both basic and clinical science. The various BoNT domains are responsible for binding to gangliosides and proteins associated with nerve cell membranes, internalization into the cell, and cleavage of one or more SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) proteins necessary for vesicle docking and fusion. Novel modifications to BoNT molecules, such as the creation of chimeras, helped identify the protein domains responsible for various aspects of BoNT action, such as localized effects. Other molecular modifications have been introduced in attempts to increase the specificity of BoNTs for autonomic or sensory neurons, with the ultimate goal of optimizing therapeutic selectivity. This research, in turn, has led to the development of BoNT-based proteins that can target non-SNARE substrates such as phosphatase and tensin homolog (PTEN). Still others are developing different BoNT serotypes, subtypes, or variants that are longer- or shorter-acting or have faster onset for various clinical purposes. New formulations of BoNTs that provide convenience for both patients and physicians are under investigation. Novel clinical uses are being evaluated for onabotulinumtoxinA, including in the prevention of post-operative atrial fibrillation. All these innovations capitalize on the unique properties of BoNTs, which continue to intrigue scientists and clinicians across numerous fields of study.

Microneedling combined with botulinum toxin-A versus microneedling combined with platelet-rich plasma in treatment of atrophic acne scars: a comparative split face study

BACKGROUND

Atrophic post-acne scarring constitutes a troublesome cosmetic concern for both patients and dermatologists. Old and new therapies as well as combinations are being introduced to achieve a satisfactory response. Microneedling has been used either alone or under different combinations for its treatment. The aim was to compare its combination with topical platelet-rich plasma versus its combination with topical Botulinum Toxin-A.

METHODS

30 subjects with different types and grades of atrophic post-acne scars completed the study. Right side of the face was treated with microneedling and platelet-rich plasma while the left side was treated microneedling and Botox. Response was assessed using two different scales. Patient satisfaction and pain were also assessed.

RESULTS

Regarding response to therapy and according to the quartile grading scale, there was no statistically significant difference between the two sides where (23.4% & 13.3%) of the right and left sides, respectively, had an excellent response. Regarding the difference in the qualitative global scarring grading system before and after treatment, there was a highly statistically significant improvement on both sides with higher improvement on the right side than left side but in a non-statistically significant way.

CONCLUSIONS

Both combinations present efficacious options for treating acne scars with comparable efficacy.

TRIAL REGISTRATION

Registered and approved prospectively by the ethical review board of the faculty of medicine, Zagazig University.

Experimental study of the effects of nitroglycerin, botulinum toxin A, and clopidogrel on bipedicled superficial inferior epigastric artery flap survival

Beneficial effects could be achieved by various agents such as nitroglycerin, botulinum toxin A (BoTA), and clopidogrel to improve skin flap ischaemia and venous congestion injuries. Eighty rats were subjected to either arterial ischaemia or venous congestion and applied to a bipedicled U-shaped superficial inferior epigastric artery (SIEA) flap with the administration of nitroglycerin, BoTA, or clopidogrel treatments. After 7 days, all rats were sacrificed for flap evaluation. Necrotic area percentage was significantly minimized in flaps treated with clopidogrel (24.49%) versus the ischemic flaps (34.78%); while nitroglycerin (19.22%) versus flaps with venous congestion (43.26%). With ischemia, light and electron microscopic assessments revealed that nitroglycerin produced degeneration of keratinocytes and disorganization of collagen fibers. At the same time, with clopidogrel administration, there was an improvement in the integrity of these structures. With venous congestion, nitroglycerin and BoTA treatments mitigated the epidermal and dermal injury; and clopidogrel caused coagulative necrosis. There was a significant increase in tissue gene expression and serum levels of vascular endothelial growth factor (VEGF) in ischemic flaps with BoTA and clopidogrel, nitroglycerin, and BoTA clopidogrel in flaps with venous congestion. With the 3 treatment agents, gene expression levels of tumor necrosis factor-α (TNF-α) were up-regulated in the flaps with ischemia and venous congestion. With all treatment modalities, its serum levels were significantly increased in flaps with venous congestion and significantly decreased in ischemic flaps. Our analyses suggest that the best treatment option for ischemic flaps is clopidogrel, while for flaps with venous congestion are nitroglycerin and BoTA.

Concomitant therapy of surgical shave excision and intralesional injections for ear keloids: Early results from a retrospective cohort study

Introduction

Keloids are hypertrophic scars that commonly arise in the ear region. The authors’ objectives were to (1) evaluate effectiveness of surgical shave excision followed by intralesional triamcinolone acetonide and onabotulinumtoxinA injections; and (2) evaluate safety and patient satisfaction.

Methods and Materials

This study was a retrospective chart review of patients who received treatment of extralesional surgical shave excision followed by intralesional triamcinolone acetonide and onabotulinumtoxinA injections to treat ear keloids at a single outpatient dermatology clinic. A prospective patient questionnaire was administered to the same patient population to collect recurrence and patient satisfaction.

Results

A total of 45 patients were included, consisting of 84.4% females (n = 38) and 15.6% males (n = 7) with a mean age of 25.5 years. Through retrospective chart review, early recurrence was seen in 6.7% of patients (n = 3), and via the prospective patient questionnaire, 11.1% of patients noted early keloid recurrence (n = 5). Of the patients who expressed their level of satisfaction in-clinic, 96.0% (n = 24) reported being satisfied or very satisfied and 4.0% (n = 1) were dissatisfied. Satisfaction was also assessed through the prospective patient questionnaire; of those who consented to the questionnaire, 100.0% (n = 24) were satisfied or very satisfied. Only 20.0% (n = 9) of all patients reported experiencing side effects, consisting of pruritus (11.1%; n = 5), tenderness (4.4%; n = 2), pain (2.2%; n = 1), and mild atrophy (2.2%; n = 1).

Conclusion

Extralesional surgical shave excision followed by intralesional triamcinolone acetonide and onabotulinumtoxinA injections may represent a promising treatment option for ear keloids.

Evidence Level: 3 retrospective cohort study.

Lay Summary

Keloids are a type of raised scar, which can be painful and itchy for patients. Keloids can occur on various part of the body, including on the ear. They are challenging to treat and tend to come back. There are many treatment options, however, there is not one universal best treatment for keloids on the ear. We hoped to discover if shave excision followed by intralesional triamcinolone acetonide and onabotulinumtoxinA injections is effective at treating keloids on the ear. In order to answer this we completed a chart review of clinic patients, who have already completed the following combination treatment for keloids on the ear. The keloids were treated first by physically removing the bulk of the keloid with a scalpel, which is called shave excision. After the removal, triamcinolone acetonide and onabotulinumtoxinA were injected directly into the keloid. The rate of patient satisfaction and the rate of the keloid returning were collected during in-clinic visits and an optional post-clinic patient questionnaire. The treatment effectiveness and side effects experienced were reported during in-clinic visits. This indicated that with the low rate of side effects, high patient satisfaction, and low rate of keloid return, this treatment combination should be considered as an option for keloids on the ear. However, since this review was completed at one clinic with a small population of patients, it is not fully known if this treatment combination will work for all patients.

Direct Inhibition of Microglia Activation by Pretreatment With Botulinum Neurotoxin A for the Prevention of Neuropathic Pain

Peripheral injection of botulinum neurotoxin A (BoNT/A) has been demonstrated to have a long-term analgesic effect in treating neuropathic pain. Around peripheral nerves, BoNT/A is taken up by primary afferent neurons and inhibits neuropeptide release. Moreover, BoNT/A could also be retrogradely transported to the spinal cord. Recent studies have suggested that BoNT/A could attenuates neuropathic pain by inhibiting the activation of spinal glial cells. However, it remains unclear whether BoNT/A directly interacts with these glial cells or via their interaction with neurons. Our aim here is to determine the direct effect of BoNT/A on primary microglia and astrocytes. We show that BoNT/A pretreatment significantly inhibits lipopolysaccharide (LPS) -induced activation and pro-inflammatory cytokine release in primary microglia (1 U/mL BoNT/A in medium), while it has no effect on the activation of astrocytes (2 U/mL BoNT/A in medium). Moreover, a single intrathecal pre-administration of a low dose of BoNT/A (1 U/kg) significantly prohibited the partial sciatic nerve ligation (PSNL)- induced upregulation of pro-inflammatory cytokines in both the spinal cord dorsal horn and dorsal root ganglions (DRGs), which in turn prevented the PSNL-induced mechanical allodynia and thermal hyperalgesia. In conclusion, our results indicate that BoNT/A pretreatment prevents PSNL-induced neuropathic pain by direct inhibition of spinal microglia activation.

Efficacy of Botulinum Toxin A for Scar Prevention After Breast Augmentation: A Randomized Double-Blind Intraindividual Controlled Trial

BACKGROUND

Botulinum toxin A benefits postsurgical scar prevention by reducing wound edge tension and inhibiting in vitro scar tissue fibrosis.

OBJECTIVE

To investigate the efficacy of botulinum toxin Type A (BTX) in improving inframammary scar appearance after primary breast augmentation.

MATERIALS AND METHODS

A prospective, double-blinded, randomized controlled trial was performed with 27 participants receiving primary augmentation mammoplasty with inframammary incisions. After skin closure, intradermal injections of BTX were administered to 1 (treated) side of the inframammary incision. The contralateral side was the control. Scars were evaluated at 3 months, 6 months, and 9 months using the Patient and Observer Scar Assessment Scale and multispectral imaging analysis.

RESULTS

Overall, 22 patients completed the study. There were no significant subjective differences between the treated and control sides except the patient's treated side had significantly higher scores than the control side at 9 months. The treated side showed significantly smaller scar widths at 6 months and 9 months (p < .001) and better scar surface textures at 9 months (p = .003) than the control side.

CONCLUSION

Subjectively, intradermal BTX injection immediately after breast augmentation skin closure caused no significant differences. Objectively, scar width and texture significantly improved at 6 months and 9 months.

Role of botulinum toxin A in improving facial erythema and skin quality

Botulinum toxin A (BTX-A) injections have become the most popular noninvasive cosmetic procedures performed worldwide. With growing interest, investigators continue to uncover an expanding array of aesthetic indications for BTX-A. Botulinum toxin A has been used off-label in the management of masseter hypertrophy for facial slimming, platysmal bands, nasal 'bunny' lines, perioral rhytides, gummy smile and scars, to name a few. Interestingly, the injection of multiple microdroplets of dilute BTX-A into the dermis, sometimes referred to as 'microbotox', has been investigated as a tool for facial rejuvenation. A handful of prospective studies and case series have demonstrated the benefit of BTX-A in the treatment of facial erythema and improving skin texture. The aim of this review is to summarize and appraise currently available data on the role of BTX-A in treating facial erythema and skin quality, with a special focus on potential pathophysiologic mechanisms.

Single Treatment, Single Depth Superficial Microfocused Ultrasound with Visualization for Rhytid Improvement

Background

Standard lifting and tightening protocols with microfocused ultrasound with visualization (MFU-V, Ultherapy) comprise the use of multiple transducer depths. We developed a shortened, single depth treatment protocol for patients seeking skin rejuvenation.

Methods

Single-center, prospective case series. Subjects with static periorbital wrinkles, perioral wrinkles, or accordion lines had a single MFU-V treatment comprising up to 340 lines (periorbital 120, perioral 100, and accordion 120) with the superficial depth transducer (10.0 MHz/1.5 mm). Efficacy was assessed using established rating scales as well as clinician- and subject-reported Global Aesthetic Improvement Scales at baseline, 90, and 180 days, and each subject served as their own control. Adverse events were documented.

Results

Nine subjects, women aged 38-64, received treatment. At 180 days, post treatment clinicians reported visible improvements in periorbital lines (6/6 cases), accordion lines (5/6 cases), and perioral lines (3/6 cases). Subjects' self-assessments mirrored those of the clinicians, reporting improvements in accordion lines (5/6 cases improved, 1/6 cases much improved), periorbital lines (3/6 cases improved, 3/6 cases much improved) and perioral lines (2/6 cases improved, 2/6 cases much improved). Subject-rated satisfaction was high (accordion lines 6/6 cases, periorbital lines 4/6 cases and perioral lines 4/6 cases). All subjects experienced mild, transient erythema; in one subject, wheals persisted for 24 hours, resolving on application of mild topical corticosteroid.

Conclusions

Shortened protocol, single depth MFU-V treatment was well-tolerated. It provided aesthetic improvements in periorbital and accordion lines, and to a lesser extent in perioral lines. Its utility as a noninvasive therapy for superficial skin rejuvenation warrants further investigation.

Profiling gene expression reveals insights into pulmonary response to aerosolized botulinum toxin type A exposure in mice

Botulinum neurotoxin type A (BoNT/A) is traditional medicine and well known for its therapeutic use as an anesthetic and in cosmetic applications that work through the inhibition of acetylcholine exocytosis in neuronal cells. BoNT/A also has the potential to function as a biological weapon due to its high mortality rate and ease of dispersal. Emerging evidence suggests that BoNT/A exhibits biological effects on nonneuronal cells. In cytology experiments, BoNT/A induces global gene expression alterations. However, pulmonary effects from exposure to aerosolized BoNT/A have not been evaluated. This study investigated the global transcriptional profile of lung tissues after botulism inhalation. A mice model of inhaled botulism was established using intratracheal exposure to aerosolized BoNT/A and described through histological examination and flow cytometry. Transcriptomic analysis revealed that genes related to acute inflammatory responses were upregulated at 12-h postexposure. Increased expression of multiple anti-inflammatory marker genes and decreased expression of pro-inflammatory marker genes were observed at 48- to 72-h postexposure, underscoring a transcriptional shift toward a pro-reparative phenotype. Histological examination and cell proportions analysis mirrored these expression patterns. Accordingly, the orchestration of a quick phenotype transition prompted by BoNT/A may have the potential for promoting the resolution of the inflammatory lung. To our knowledge, this study represents the first research to investigate the pulmonary transcriptional responses of aerosolized BoNT/A exposure; the results may provide new insights in elucidating the molecular mechanism for pulmonary inhaled botulism and highlight the potential therapeutic application of BoNT/A in mitigating inflammatory conditions.

Dramatic neurological and biological effects by botulinum neurotoxin type A on SH-SY5Y neuroblastoma cells, beyond the blockade of neurotransmitter release

BACKGROUND

Gene expression profile analysis on mammalian cell lines and animal models after exposure to botulinum neurotoxin (BoNT) has been investigated in several studies in recent years. Microarray analysis provides a powerful tool for identifying critical signaling pathways involved in the biological and inflammatory responses to BoNT and helps determine the mechanism of the function of botulinum toxins. One of the pivotal clinical characteristics of BoNT is its prolonged on-site effects. The role of BoNT on the blockage of neurotransmitter acetylcholine release in the neuromuscular junction has been well established. However, the effects of the treatment time of BoNT on the human cellular model and its potential mechanism remain to be defined.

METHODS

This study aimed to use gene microarray technology to compare the two physiological critical time points of BoNT type A (BoNT/A) treatment of human neuroblastoma cells and to advance our understanding of the profound biological influences that toxin molecules play in the neuronal cellular system. SH-SY5Y neuroblastoma cells were treated with BoNT/A for 4 and 48 h, which represent the time needed for the entrance of toxin into the cells and the time necessary for the initial appearance of the on-site effects after BoNT application, respectively.

RESULTS

A comparison of the two time points identified 122 functional groups that are significantly changed. The top five groups are alternative splicing, phosphoprotein, nucleus, cytoplasm, and acetylation. Furthermore, after 48 h, there were 744 genes significantly up-regulated, and 624 genes significantly down-regulated (p‹ 0.01). These genes fell into the following neurological and biological annotation groups: Nervous system development, proteinaceous extracellular matrix, signaling pathways regulating pluripotency of stem cells, cellular function and signal transduction, and apoptosis. We have also noticed that the up-regulated groups contained neuronal cell development, nervous system development, and metabolic processes. In contrast, the down-regulated groups contained many chromosomes and cell cycle categories.

CONCLUSIONS

The effects of BoNT/A on neuronal cells extend beyond blocking the neurotransmitter release, and that BoNT/A is a multifunctional molecule that can evoke profound cellular responses which warrant a more in-depth understanding of the mechanism of the toxin's effects after administration.

Intradermal injection of incobotulinumtoxinA for face lifting

Intradermal injection of botulinumtoxinA (BoNT/A) has been used off-label by many clinicians for the purpose of face-lifting effect. Some studies on AbobotulinumtoxinA (AboA) demonstrated clinical efficacy on face-lifting effect when comparing to normal saline solution (NSS). So far, there is no split-face comparison study on face-lifting effect of IncobotulinumtoxinA (IncoA). The objective of this study was to compare the face-lifting effect of IncoA intradermal injection and NSS. Twenty-two subjects were enrolled and randomly injected with IncoA at 1:6 cc dilution (100 unit or 1 vial in 6 cc of NSS) on one side, and NSS on the other side by using intradermal injection technique. Standardized photographic documentation with 2-, and 3-dimentional imaging system (Vectra H1, Canfield Scientific, Inc., Fairfield, NJ) were obtained at baseline, and at 2 weeks after treatment. The face-lifting effect was graded by the subjects and two blinded dermatologists, using photographic comparison. Side effects were also recorded at the end of the study. Immediate face-lifting was identified on the side that was treated with IncoA by blinded injectors in 63.6% of patients. Of all subjects, 17 (77.3%) have noticed the improvement of skin laxity on the side that was treated with IncoA at 2 weeks after treatment. The difference in facial contouring volume measured by Vectra H1 imaging system on IncoA side was significantly higher (P = .033) when comparing to NSS side in patients aged <36 years old. However, there was no statistically significant difference in face-lifting when comparing between IncoA and NSS evaluated by two blinded dermatologists (P = 1.00). Facial asymmetry was found in 36.4% of subjects. This study demonstrated the face-lifting effect of IncoA intradermal injection. Further studies with larger number of subjects and proper method of evaluation should be done to verify these findings.

The effect of botulinum toxin type A in different dilution on the contraction of fibroblast-In vitro study

BACKGROUND

Botulinum toxin type A (BoNT-A) may directly remodel dermal tissues or induce a loss of normal morphology and cytoplasmic retraction and spread. Intradermal injection was claimed to produce a dermo-lifting effect, including midface lifting by using low concentration with variable dilution.

OBJECTIVE

To understand how intradermal BoNT-A achieves tissue lifting, we examined different type of BoNT-A and their effects on dermal fibroblast contraction.

METHODS

Normal human dermal fibroblasts were treated with onabotulinumtoxin (ONA), abobotulinumtoxin (ABO), prabotulinumtoxinA (PRABO), incobotulinumtoxinA (INCO), and letibotulinumtoxin A (LETI) in dilutions used in real-world practice. Fifty fibroblasts per dilution were photographed and measured the length to demonstrate their contraction every 2 hours from baseline (0 hours) to 12 hours post-treatment.

RESULTS

ONA did not significantly decrease fibroblast lengths, at any timepoint or dilution. At 1:7 dilution ratios, ABO decreased fibroblast lengths after 2 hours and significantly after 10-12 hours. At 1:7, 1:8, 1:9, and 1:10 dilution, PRABO decreased length, and most rapidly at 1:7 and 1:8. At 1:6, 1:8, 1:9, and 1:10 dilution, INCO decreased lengths almost immediately. At 1:6 dilution, INCO decreased lengths almost immediately. At 1:7 dilution, INCO decreased lengths after 2-4 hours, while at 1:8, 1:9, and 1:10 dilution, INCO decreased lenghts nearly imediately. LETI decreased lengths at all dilutions except 1:9, with near-immediate effects at 1:6, 1:7, 1:8, and 1:10. At 1:4 dilution, LETI decreased lengths from 1 hour.

CONCLUSIONS

Different commercial preparations of BoNT-A toxins cause different fibroblast contractions in vitro. Product selection and dilution used may affect the clinical outcome of intradermal injection of BoNT-A for face lifting.

The modern approach of advanced botulinum toxin therapy: application of various dilutions, techniques and levels of administration

One modern direction of botulinum toxin therapy in aesthetic medicine is its individualization by taking into account patients’ specific characteristics. On the example of using incobotulinumtoxin A (botulinum toxin type A, BTA), this paper considers the possibility of using the entire range of its concentrations in creating a differentiated approach to correcting mimic wrinkles in different zones and muscular levels. This is expected to achieve the required level of individualization for an optimal aesthetic result. Aim. To assess and justify the efficacy of BTA (on the example of incobotulinumtoxin A) in various concentrations for correcting mimic wrinkles in different zones and muscular levels.

The Cellular Response of Keloids and Hypertrophic Scars to Botulinum Toxin A: A Comprehensive Literature Review

BACKGROUND

Keloids and hypertrophic scars are conditions of pathologic scarring characterized by fibroblast hyperproliferation and excess collagen deposition. These conditions significantly impact patients by causing psychosocial, functional, and aesthetic distress. Current treatment modalities have limitations. Clinical evidence indicates that botulinum toxin A (BoNT-A) may prevent and treat keloids and hypertrophic scars.

OBJECTIVE

To examine investigated cellular pathways involved in BoNT-A therapeutic modulation of keloids and hypertrophic scars.

METHODS

The authors searched PubMed, Embase, and Web of Science for basic science articles related to botulinum toxin therapy, scarring, fibroblasts, keloids, and hypertrophic scars.

RESULTS

Eleven basic science articles involving keloids and hypertrophic scars were reviewed.

DISCUSSION

BoNT-A may reduce skin fibrosis by decreasing fibroblast proliferation, modulating the activity of transforming growth factor-β, and reducing transcription and expression of profibrotic cytokines in keloid-derived and hypertrophic scar-derived dermal fibroblasts. BoNT-A may modulate collagen deposition, but there is a paucity of evidence regarding specific mechanisms of action.

CONCLUSION

Overall, BoNT-A has the potential to prevent or treat pathologic scars in patients with a known personal or family history of keloids and hypertrophic scars, which may improve patient psychosocial distress and reduce clinic visits and health care costs. Variability in keloid and hypertrophic scar response to BoNT-A may be due to interexperiment differences in dosing, tissue donors, and assay sensitivity.

The non-neuronal and nonmuscular effects of botulinum toxin: an opportunity for a deadly molecule to treat disease in the skin and beyond

There is growing evidence that botulinum neurotoxins (BoNTs) exhibit biological effects on various human cell types with a host of associated clinical implications. This review aims to provide an update on the non-neuronal and nonmuscular effects of botulinum toxin. We critically analysed recent reports on the structure and function of cellular signalling systems subserving biological effects of BoNTs. The BoNT receptors and intracellular targets are not unique for neurotransmission. They have been found in both neuronal and non-neuronal cells, but there are differences in how BoNT binds to, and acts on, neuronal vs. non-neuronal cells. The non-neuronal cells that express one or more BoNT/A-binding proteins, and/or cleavage target synaptosomal-associated protein 25, include: epidermal keratinocytes; mesenchymal stem cells from subcutaneous adipose; nasal mucosal cells; urothelial cells; intestinal, prostate and alveolar epithelial cells; breast cell lines; neutrophils; and macrophages. Serotype BoNT/A can also elicit specific biological effects in dermal fibroblasts, sebocytes and vascular endothelial cells. Nontraditional applications of BoNT have been reported for the treatment of the following dermatological conditions: hyperhidrosis, Hailey-Hailey disease, Darier disease, inversed psoriasis, aquagenic palmoplantar keratoderma, pachyonychia congenita, multiple eccrine hydrocystomas, eccrine angiomatous hamartoma, eccrine sweat gland naevi, congenital eccrine naevus, Raynaud phenomenon and cutaneous leiomyomas. Experimental studies have demonstrated the ability of BoNT/A to protect skin flaps, facilitate wound healing, decrease thickness of hypertrophic scars, produce an anti-ageing effect, improve a mouse model of psoriasiform dermatitis, and have also revealed extracutaneous effects of BoNT arising from its anti-inflammatory and anticancer properties. BoNTs have a much wider range of applications than originally understood, and the individual cellular responses to the cholinergic impacts of BoNTs could provide fertile ground for future studies.

Efficacy and possible mechanisms of Botulinum Toxin type A on hypertrophic scarring

BACKGROUND

Clinical observations indicate that Botulinum toxin type A (BTXA) can inhibit the growth and improve the eventual appearance of hypertrophic scarring. However, the molecular mechanism remains unclear.

OBJECTIVE

We used human keloid fibroblasts to investigate the molecular mechanism of BTXA on hypertrophic scarring.

METHODS

Different concentrations of BTXA (0.01, 0.1, 1, and 10 U/L) were used to treat keloid fibroblasts. Changes in cellular morphology, viability, proliferation, cell cycle, and apoptosis were observed by immunofluorescence, MTT assay, and flow cytometry. In addition, real-time qPCR and Western blotting were used to explore the potential molecular mechanisms.

RESULTS

Keloid fibroblast viability decreased with increasing BTXA dose. After BTXA treatment, the volume of keloid fibroblasts cells increased, but the nucleus of cells shrunk. Long thin dendrites were formed as the concentration of BTXA increased. Furthermore, the proliferation and S phase of keloid fibroblasts were inhibited by BTXA. Matrix metalloproteinase (, MMP)-1 and -2 RNA and protein showed high expression, but TGF-β1 and MMP-9 showed low expression than the control.

CONCLUSION

Botulinum toxin type A may promote the healing of scars by inhibiting the proliferation of keloid fibroblasts and regulating the expression of TGF-β1, which could affect the expression of MMP-1 and MMP-2. This study provides theoretical support for the clinical application of BTXA to control hypertrophic scarring.

Botulinum toxin type A affects the transcriptome of cell cultures derived from muscle biopsies of controls and spastic patients

Botulin toxin (BTX) is widely used for treating skeletal muscle spasticity. Experimental reports on BTX treatment were mainly focused on the neuromuscular junction, while relatively little is known about toxin effects on the muscle cell itself. We investigated possible impact of BTX type A on skeletal muscle cell transcriptome by microarray analysis in muscle-derived cell cultures (fibroblasts, myoblasts and myotubes) from controls and spastic patients, and results were then validated at transcript and protein level. BTX-A treatment of control cells induced major changes in the myogenic component of the transcriptome, whereas the same treatment had a negligible effect in the fibrogenic component. BTX-A treatment of cell cultures from spastic patients induced an increased number of genes differentially expressed both in the fibrogenic and myogenic components. Specifically, BTX-A had a major effect on cell cycle-related genes in myoblasts, on muscle contraction-related genes in myotubes, and on extracellular matrix-related genes in fibroblasts from spastic patients. Our findings show that in vitro BTX-A treatment differentially affects transcript expression in muscle cells from spastic patients compared to those from controls suggesting a direct effect of BTX-A on muscle-specific functional pathways.

Preventive, Cumulative Effects of Botulinum Toxin Type A in Facial Aesthetics

BACKGROUND

Botulinum toxin Type A (BoNTA) is the gold standard for the treatment of dynamic rhytides in the face. Recently, clinical observation suggests that individuals who receive regular injections of BoNTA experience ongoing wrinkle reduction and improvements in overall skin quality not observed in those treated sporadically.

OBJECTIVE

To review scientific evidence of qualitative changes in the skin and the possibility of indirect or direct effects on fibroblasts affecting fibroblast activity, including collagen production, after repeated treatment with BoNTA.

MATERIALS AND METHODS

We examined the literature for supporting evidence of the effect of repeated treatment cycles on wrinkle reduction and skin quality; histological changes in collagen structure; alterations in biomechanical features of the skin; and potential fibroblastic response.

RESULTS

Apparent cumulative improvement on wrinkle reduction and additional skin quality attributes with regular BoNTA treatments suggests an ongoing process of dermal repair. Clinical observation suggests that BoNTA injections stimulate collagen production and lead to a reorganization of the collagen network within the extracellular matrix, which in turn may produce improvements in features associated with more youthful skin. Moreover, evidence suggests that BoNTA may have a direct or indirect effect on fibroblast activity.

CONCLUSION

Clinical observation of progressive wrinkle reduction and qualitative improvements in a number of skin attributes that accumulate with more frequent injections of BoNTA suggest an ongoing process of repair leading to prolonged and cumulative effects.

Evaluation of botulinum toxin type A effectiveness in preventing postoperative intraperitoneal adhesions

Purpose

Postoperative intraperitoneal adhesions (PIAs) are one of the most important problems surgeons have to face after laparotomies. In this study, we aimed to evaluate the effectiveness of local application of botulinum toxin type A (BoNT-A) in various dosages on the prevention of intra-abdominal adhesions in rats with experimental intra-abdominal adhesions.

Methods

Forty Wistar Albino female rats were randomly separated into 4 groups. The 4 groups were determined as follows: Control (group 1, n = 10); Sham (group 2, n = 10); 10-µg/kg low-dose BoNT-A (group 3, n = 10) and 30-µg/kg high-dose BoNT-A (group 4, n = 10). Subserosal injuries were created on the caecum of all rats. Laparotomy was performed on the fifth day. Adhesion scores, histopathological examination, and E-cadherin expression levels were evaluated.

Results

General adhesion scores for groups 1 and 2 were determined to be significantly high when compared to group 4 (P < 0.001). A significant difference was also determined between groups 3 and 4 in terms of general adhesion scores (P < 0.05). In pair comparisons, a significant decrease in high-dose BoNT-A group (group 4) when compared to groups 1 and 2 in terms of neovascularization, fibroblast density, collagen deposition and inflammatory cell count was determined (P < 0.05).

Conclusion

A significant decrease was observed only in postoperative PIAs in the high-dose BoNT-A group between all 4 rat-groups with experimentally created postoperative PIAs. In this study, high-dose BoNT-A is determined to be an effective agent in preventing postoperative PIAs.

The Effect of Botulinum Toxin Type A on Expression Profiling of Long Noncoding RNAs in Human Dermal Fibroblasts

Objective. This study was aimed at analyzing the expressions of long noncoding RNAs (lncRNAs) in Botulinum Toxin Type A (BoNTA) treated human dermal fibroblasts (HDFs) in vitro. Methods. We used RNA sequencing to characterize the lncRNAs and mRNAs transcriptome in the control and BoNTA treated group, in conjunction with application of GO (gene ontology) analysis and KEGG (kyoto encyclopedia of genes and genomes) analysis to delineate the alterations in gene expression. We also obtained quantitative real time polymerase chain reaction (qRT-PCR) to confirm some differentially expressed genes. Results. Numerous differentially expressed genes were observed by microarrays between the two groups. qRT-PCR confirmed the changes of six lncRNAs (RP11-517C16.2-001, FR271872, LOC283352, RP11-401E9.3, FGFR3P, and XXbac-BPG16N22.5) and nine mRNAs (NOS2, C13orf15, FOS, FCN2, SPINT1, PLAC8, BIRC5, NOS2, and COL19A1). Farther studies indicated that the downregulating effect of BoNTA on the expression of FGFR3P was time-related and the dosage of BoNTA at a range from 2.5 U/10⁶ cells to 7.5 U/10⁶ cells increased the expression of FGFR3P and COL19A1 in HDFs as well. Conclusion. The expression profiling of lncRNAs was visibly changed in BoNTA treated HDFs. Further studies should focus on several lncRNAs to investigate their functions in BoNTA treated HDFs and the underlying mechanisms.

Inhibitory effects of Schisandra chinensis extract on acne-related inflammation and UVB-induced photoageing

CONTEXT

Schisandra chinensis (Turcz.) Baill. (Schisandraceae) fruit extract (SFE) has been reported to induce non-specific tissue protection against inflammation in vivo. However, the effects of SFE on Propionibacterium acnes-stimulated acne and UVB-irradiated photoageing have yet to be investigated.

OBJECTIVE

To systematically investigate the effects of SFE against P. acnes and photoageing in vitro.

MATERIALS AND METHODS

Qualitative and quantitative analyses of SFE were performed by HPLC. SFE concentrations from 2.5 to 50 μg/mL were tested. Specifically, ELISA was used to examine the levels of pro-inflammatory cytokines in THP-1 cells as well as of collagen I and matrix metalloproteinases-1 in HDF cells. The anti-bacterial effect of SFE was determined using the microdilution broth method. Glutathione and malondialdehyde levels were examined using the colorimetric and TBA methods, respectively. The degree of ageing was determined by cytochemical staining.

RESULTS

SFE significantly inhibited P. acnes growth (MIC 0.5 mg/mL) and 50 μg/mL of SFE suppressed the production of interleukin-1β, interleukin-8 and tumour necrosis factor α, by 59.67%, 62.69% and 68.30%, respectively, in P. acnes-stimulated THP-1 cells. Additionally, 10 μg/mL of SFE suppressed photoageing in UVB-exposed fibroblasts by decreasing metalloproteinase levels by 88.4%, inducing collagen by 58.4% and activating the anti-oxidant defence system, by limiting lipid peroxidation by 51.1% and increasing glutathione production by 34.1% (2.5 μg/mL SFE).

DISCUSSION AND CONCLUSION

These results indicated that SFE could significantly ameliorate the inflammatory state in P. acnes-stimulated THP-1 and UVB-irradiated HDF cells, suggesting its potential as a novel agent for acne therapy and photoageing prevention.

Alteration of Skin Mechanical Properties in Patients Undergoing Botulinum Toxin Type A Injections of Forehead Rhytides

BACKGROUND

Although application of botulinum toxin type A (BTX-A) for the treatment of forehead rhytides has become very popular, the effects of its intramuscular injections on the skin mechanical properties remain unclear.

OBJECTIVES

We prospectively investigated the alterations in the mechanical properties of the skin of patients who received intramuscular injections of botulinum toxin A (BTX-A) for forehead rhytides and compared two injection doses.

METHODS

Of the 42 enrolled patients, one randomly assigned half received intramuscular injections of two units (group I), and the other half received four units (group II) of BTX-A in each injection point. The baseline and post-treatment skin mechanical parameters, including gross elasticity (R2), net elasticity (R5), viscoelastic ratio (R6) and biological elasticity (R7), were measured using the Cutometer(®) and compared.

RESULTS

Treatment with BTX-A resulted in significant overall alterations in the mechanical properties of skin at the injection sites of both treatment groups during the 16-week period, and no significant differences were observed between groups. Significant decreases in biological elasticity, net elasticity and viscoelasticity properties were observed at 2 weeks follow-up and began to recover at that time. All of the skin mechanical properties recovered to baseline levels by 16 weeks of follow-up in both dosage groups, which indicates that the higher dosage (4 units) did not delay relapse compared to the two-unit dosage.

CONCLUSIONS

We concluded that intramuscular injections of BTX-A significantly regulated the gross elasticity, net elasticity, functional elasticity and viscoelastic elasticity at the injection point over a radius of 1.5 cm at 2, 4 and 8 weeks follow-up. The alteration in the skin measurements had completely diminished by the 16-week follow-up.

LEVEL OF EVIDENCE IV

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 .

The Efficacy and Safety of Fractional CO₂ Laser Combined with Topical Type A Botulinum Toxin for Facial Rejuvenation: A Randomized Controlled Split-Face Study

Objective. We evaluated synergistic efficacy and safety of combined topical application of Botulinum Toxin Type A (BTX-A) with fractional CO₂ laser for facial rejuvenation. Methods. Twenty female subjects were included for this split-face comparative study. One side of each subject's cheek was treated with fractional CO₂ plus saline solution, and the other side was treated with fractional CO₂ laser plus topical application of BTX-A. Patients received one session of treatment and evaluations were done at baseline, one, four, and twelve weeks after treatment. The outcome assessments included subjective satisfaction scale; blinded clinical assessment; and the biophysical parameters of roughness, elasticity, skin hydration, transepidermal water loss (TEWL), and the erythema and melanin index. Results. BTX-A combined with fractional CO₂ laser sides showed higher physician's global assessment score, subject satisfaction score, roughness, skin hydration, and skin elasticity compared to that of fractional CO₂ plus saline solution side at 12 weeks after treatment. TEWL and erythema and melanin index showed no significant differences between two sides at baseline, one, four, and twelve weeks after treatment. Conclusion. Topical application of BTX-A could enhance the rejuvenation effect of fractional CO₂ laser.

Botulinum neurotoxin type A: Actions beyond SNAP-25?

Botulinum neurotoxin type A (BoNT/A), the most potent toxin known in nature which causes botulism, is a commonly used therapeutic protein. It prevents synaptic vesicle neuroexocytosis by proteolytic cleavage of synaptosomal-associated protein of 25 kDa (SNAP-25). It is widely believed that BoNT/A therapeutic or toxic actions are exclusively mediated by SNAP-25 cleavage. On the other hand, in vitro and in vivo findings suggest that several BoNT/A actions related to neuroexocytosis, cell cycle and apoptosis, neuritogenesis and gene expression are not necessarily mediated by this widely accepted mechanism of action. In present review we summarize the literature evidence which point to the existence of unknown BoNT/A molecular target(s) and modulation of unknown signaling pathways. The effects of BoNT/A apparently independent of SNAP-25 occur at similar doses/concentrations known to induce SNAP-25 cleavage and prevention of neurotransmitter release. Accordingly, these effects might be pharmacologically significant. Potentially the most interesting are observations of antimitotic and antitumor activity of BoNT/A. However, the exact mechanisms require further studies.

Anti-photoaging potential of Botulinum Toxin Type A in UVB-induced premature senescence of human dermal fibroblasts in vitro through decreasing senescence-related proteins

This study was aimed to evaluate the anti-photoaging effects of Botulinum Toxin Type A (BoNTA) in Ultraviolet B-induced premature senescence (UVB-SIPS) of human dermal fibroblasts (HDFs) in vitro and the underlying mechanism. We established a stress-induced premature senescence model by repeated subcytotoxic exposures to Ultraviolet B (UVB) irradiation. The aging condition was determined by cytochemical staining of senescence-associated β-galactosidase (SA-β-gal). The tumor suppressor and senescence-associated protein levels of p16(INK-4a), p21(WAF-1), and p53 were estimated by Western blotting. The G1 phase cell growth arrest was analyzed by flow cytometry. The mRNA expressions of p16, p21, p53, COL1a1, COL3a1, MMP1, and MMP3 were determined by real-time PCR. The level of Col-1, Col-3, MMP-1, and MMP-3 were determined by ELISA. Compared with the UVB-irradiated group, we found that the irradiated fibroblasts additionally treated with BoNTA demonstrated a decrease in the expression of SA-β-gal, a decrease in the level of tumor suppressor and senescence-associated proteins, a decrease in the G1 phase cell proportion, an increase in the production of Col-1 and Col-3, and a decrease in the secretion of MMP-1 and MMP-3, in a dose-dependent manner. Taken together, these results indicate that BoNTA significantly antagonizes premature senescence induced by UVB in HDFs in vitro, therefore potential of intradermal BoNTA injection as anti-photoaging treatment still remains a question.

Skin Biomechanical Changes after Injection of Onabotulinum Toxin A: Prospective Assessment of Elasticity and Pliability

OBJECTIVE

This study aimed to test the hypothesis that the administration of onabotulinum toxin A will result in an increase in skin pliability and elasticity.

STUDY DESIGN

A prospective case series with planned data collection in which patients were treated with onabotulinum toxin and assessed at baseline, 2 weeks post-injection, and 2 months post-injection.

SETTING

A private cosmetic surgery clinic associated with a tertiary academic hospital.

SUBJECTS AND METHODS

Forty women were prospectively enrolled to receive onabotulinum toxin A into their glabella, forehead, and lateral orbit. Outcomes were assessed at baseline, 2 weeks posttreatment, and 2 months posttreatment using the Cutometer MPA 580. Skin pliability (Uf) and the elastic recoil (Ua/Uf) were recorded as the 2 primary outcome measures.

RESULTS

There was a significant effect of onabotulinum toxin on skin elasticity (f = 47.8, P = .001) with a mean (+/- SE) increase in elastic recoil of 20% (4.4%) for the glabellar region (P < .001) and 18% (4.0%) for the lateral orbit (P < .0001). There was a significant effect of the treatment on skin pliability (f = 46.9, P < .001) with a mean (+/- SE) increase of 26% (5.4%) for the lateral orbit (P = .001) and 52% (8.3%) for the glabellar region (P < .001).

CONCLUSION

Injection of onabotulinum toxin into the lateral orbital, forehead, and glabellar regions results in skin that has increased pliability as well as increased elastic recoil. Although this study demonstrates the positive effect of onabotulinum toxin on biomechanical parameters, it is unclear what specific histological changes are occurring within the skin.