Botulin Toxin Use in Scars/Keloids Treatment

Pruritus in keloid scars: mechanisms and treatments

Keloids occur after cutaneous injury and can cause distress due to physical appearance and associated symptoms such as pain and pruritus. Keloid-associated pruritus is a common manifestation and has negative impacts on quality of life. The mechanism underlying this type of pruritus is multifactorial and thought to involve small nerve fiber damage, neurogenic inflammation, and a Th2-predominant inflammatory response. Various agents have been shown to reduce keloid pruritus, including intralesional corticosteroids, botulinum toxin A, 5-fluorouracil, and bleomycin. Other treatment modalities such as cryotherapy and hyperbaric oxygen therapy are also effective. Future treatments targeting the mechanisms involved in keloid-associated itch could provide improvements in pruritus and quality of life in these patients, but further studies on the efficacy of these agents are needed.

Treatment and Improvement of Healing after Surgical Intervention

The development of abnormal scars has a great impact on people's well-being, and improving scarring outcomes after surgery is a field that currently lacks consensus. This review aims to identify newly researched approaches to improving the quality of surgical scars. A systematic search of PubMed, Scopus, Web of Science, and ScienceDirect was conducted between 13 May 2023 and 17 May 2023, in accordance with the recommendations of the PRISMA Statement. Study selection and analysis of methodological quality were performed in parts, independently and blindly, based on eligibility criteria. The 21 prospective, comparative, and randomized studies reviewed included 1057 subjects and studied approaches such as topical applications of creams with herbal extracts and silicone gels, growth factors, negative pressure dressings, oligonucleotides, intralesional injection of compounds such as botulinum toxin, skin closure techniques such as suturing and tissue adhesive, and laser treatments. There are recent research techniques that generate good results and are really promising to improve the results of surgical scars; however, the available evidence is extremely limited in some cases, and it is necessary to deepen its analysis to obtain reliable action protocols in each type of surgery.

Mechanotransduction in skin wound healing and scar formation: Potential therapeutic targets for controlling hypertrophic scarring

Hypertrophic scarring (HTS) is a major source of morbidity after cutaneous injury. Recent studies indicate that mechanical force significantly impacts wound healing and skin regeneration which opens up a new direction to combat scarring. Hence, a thorough understanding of the underlying mechanisms is essential in the development of efficacious scar therapeutics. This review provides an overview of the current understanding of the mechanotransduction signaling pathways in scar formation and some strategies that offload mechanical forces in the wounded region for scar prevention and treatment.

Potency of bacterial sialidase Clostridium perfringens as antiviral of Newcastle disease infections using embryonated chicken egg in ovo model

Background and Aim: Clostridium toxins are widely used as medicinal agents. Many active metabolic enzymes, including sialidase (neuraminidase), hyaluronidase, and collagenase, contribute to the mechanism of action of these toxins. Sialidase from Clostridium perfringens recognizes and degrades sialic acid receptors in the host cell glycoprotein, glycolipid, and polysaccharide complexes. Sialic acid promotes the adhesion of various pathogens, including viruses, under pathological conditions. This study aimed to investigate the potential of C. perfringens sialidase protein to inhibit Newcastle disease virus (NDV) infection in ovo model. Materials and Methods: C. perfringens was characterized by molecular identification through polymerase chain reaction (PCR) and is cultured in a broth medium to produce sialidase. In addition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis was conducted to characterize the sialidase protein. In contrast, enzymatic activity and protein concentration were carried out using a neuraminidase assay kit and Bradford to obtain suitable active substances. Furthermore, embryonated chicken egg models were used to observe the toxicity of several sialidase doses. Then, the hemagglutination (HA) titer was obtained, and absolute quantitative reverse transcription–PCR assay was performed to measure the viral replication inhibitory activity of sialidase against NDV. Results: Each isolate had a specific sialidase gene and its product. The sialidase derived from C. perfringens could hydrolyze the sialic acid receptor Neu5Ac (2,6)-Gal higher than Neu5Ac (2,3)Gal in chicken erythrocytes, as observed by enzyme-linked lectin assay. A significant difference (p = 0.05) in the HA titer in the pre-challenge administration group at dosages of 375 mU, 187.5 mU, and 93.75 mU in the competitive inhibition experiment suggests that sialidase inhibits NDV reproduction. Quantification of infective viral copy confirmed the interference of viral replication in the pre-challenge administration group, with a significant difference (p = 0.05) at the treatment doses of 750 mU, 375 mU, and 46.87 mU. Conclusion: The potency of sialidase obtained from C. perfringens was shown in this study, given its ability to reduce the viral titer and copy number in allantoic fluids without adversely impacting the toxicity of the chicken embryo at different concentrations.

Identification and characterization of four immune-related signatures in keloid

A keloid is a fibroproliferative disorder of unknown etiopathogenesis that requires ill-defined treatment. Existing evidence indicates that the immune system plays an important role in the occurrence and development of keloid. However, there is still a lack of research on the immune-related signatures of keloid. Here we identified immune-related signatures in keloid and explored their pathological mechanisms. Transcriptomic datasets (GSE7890, GSE92566, and GSE44270) of keloid and normal skin tissues were obtained from the Gene Expression Omnibus database. The overlap of differentially expressed genes and immune-related genes was considered as differentially expressed immune-related genes (DEIGs). Functional analysis, expression, and distribution were applied to explore the function and characteristics of DEIGs, and the expression of these DEIGs in keloid and normal skin tissues was verified by immunohistochemistry. Finally, we conducted interactive network analysis and immune infiltration analysis to determine the therapeutic potential and immune correlation. We identified four DEIGs (LGR5, PTN, JAG1, and DKK1). In these datasets, only GSE7890 met the screening criteria. In the GSE7890 dataset, DKK1 and PTN were downregulated in keloid, whereas JAG1 and LGR5 were upregulated in keloid. In addition, we obtained the same conclusion through immunohistochemistry. Functional analysis indicated that these four DEIGs were mainly involved in stem cell, cell cycle, UV response, and therapy resistance. Through interactive network analysis, we found that these DEIGs were associated with drugs currently used to treat keloid, such as hydrocortisone, androstanolone, irinotecan, oxaliplatin, BHQ-880, and lecoleucovorin. Finally, many immune cells, including CD8⁺ T cells, resting memory CD4⁺ T cells, and M1 macrophages, were obtained by immune infiltration analysis. In conclusion, we identified four immune signaling molecules associated with keloid (LGR5, PTN, JAG1, and DKK1). These immune-related signaling molecules may be important modules in the pathogenesis of keloid. Additionally, we developed novel therapeutic targets for the treatment of this challenging disease.

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.

Pruritus in Keloid Scars: Mechanisms and Treatments

Keloids are scars that extend beyond the margins of an insulting cutaneous injury. Keloids are often thought to be primarily a cosmetic issue, as they are typically quite raised and pigmented. However, these scars also present with functional symptoms of pruritus and pain that significantly impact quality of life. The symptom of pruritus is frequently overlooked by dermatologists, and treatments are often primarily focused on the gross appearance of the scar. This review describes the prevalence and importance of pruritus in keloids. In addition, the putative mechanisms underlying the development of keloid pruritus, which include neuronal and immunological mechanisms, are discussed. Furthermore, this review describes keloid treatments that have been shown to reduce pruritus, treatments that specifically target the itch, and emerging therapies.

Botulinum Toxin Type A Injection for Mammoplasty and Abdominoplasty Scar Management: A Split-Scar Double-Blinded Randomized Controlled Study

BACKGROUND

Scars are inevitable results of surgical procedures, and prevention of them is still a major problem in the field of cosmetic surgery. Although various studies have been performed on botulinum toxin-A (BoNT-A) injection for the prevention of hypertrophic scars, the exact mechanism remains unclear.

METHODS

This prospective, double-blinded, randomized study was performed on 19 patients who underwent mammoplasty and abdominoplasty surgery in Razi Hospital from October 2018 to December 2019. Single session of treatment was performed, where XEOMIN was allocated to one half of the scar and 0.9% saline to the control half. 3 and 6 months later, scars were assessed using the modified Stony Brook Scar Evaluation Scale (SBSES).

RESULTS

In total, 19 patients who completed the study were analyzed. mSBSES at the third month (P value < 0.001; 3.34 ± 1.59 vs 1.5 ± 1.36) and the sixth month (P value < 0.001; 4.89 ± 1.83 vs 2.39 ± 1.82) showed a significant difference between the treatment and control groups. In the subset analysis, there was significant difference between BoNT-A and control in all four items including width, height, color, and scar visibility at months 3 and 6, and the BoNT-A-treated sides had higher scores in all items.

CONCLUSION

BoNT-A has a significant effect on scar prevention due to mammoplasty and abdominoplasty compared to placebo and results in decreased erythema, height, width and reduces incision line visibility. Moreover, its effect increases significantly over time from months 3 to 6.

LEVEL OF EVIDENCE II

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 .

Botulinum toxin type A attenuates hypertrophic scar formation via the inhibition of TGF-β1/Smad and ERK pathways

BACKGROUND

Hypertrophic scar is a common complication in would healing process, and how to effectively prevent and treat it has been a hot and difficult research issue. Previous studies have showed that botulinum toxin type A (BTA) has effects on the prevention and treatment of hypertrophic scar, but little is known about the specific mechanisms.

OBJECTIVE

This study aimed to explore the potential mechanisms of BTA on the inhibition of hypertrophic scar formation.

METHODS

Hypertrophic scar-derived human fibroblasts were cultured and then treated with transforming growth factor-β1 (TGF-β1) and various concentrations of BTA. Cell proliferation and viability were measured by CellTiter 96® AQueous One Solution Cell Proliferation Assay and trypan blue staining, respectively. The total amount of collagen was examined using Sirius red staining. Collagen I and Collagen III in the culture supernatant were evaluated by enzyme-linked immunosorbent assay. Reverse transcription-quantitative polymerase chain reaction and Western blot analysis were performed to detect the transcription and translation levels.

RESULTS

Our results revealed that BTA decreased the proliferation of hypertrophic scar-derived human fibroblasts. The mRNA and protein expression levels of alpha-smooth muscle actin, collagen I, and collagen III induced by TGF-β1 were inhibited by BTA in a dose-dependent manner. BTA also inhibited the phosphorylation of Smad2/3 and ERK.

CONCLUSION

BTA decreased the proliferation of fibroblasts and prevented overdeposition of ECM through the inhibition of the TGF-β1/Smad and ERK pathways. The findings of this study provide new scientific reference for the prevention and treatment of hypertrophic scar.

Suppression of neuropeptide by botulinum toxin improves imiquimod-induced psoriasis-like dermatitis via the regulation of neuroimmune system

BACKGROUND

Psoriasis is a multifactorial disease arises from a complex interaction of genetics, immune system, and environmental aspects. IL-23/Th17 immune axis has been considered as a primary modulator in psoriasis. In addition, several findings imply that nervous system may take a part in the pathogenesis of psoriasis, suggesting that nervous system, through its neuropeptide, may interact with immune system and lead to the formation of psoriasis.

OBJECTIVE

We aimed to ascertain the role of neuropeptides secreted from neurons in the pathogenesis of psoriasis in vivo.

METHODS

The release of neuropeptide was inhibited by injecting Botulinum toxin B (BTX-B) on Imiquimod (IMQ)-induced psoriasis-like dermatitis mice model. Quantification of skin dermatitis, infiltrating inflammatory cells, and the production of cytokines at the lesional skin area were performed by PSI score, immunostaining, and real-time PCR. We also tested the effect of selective CGRP antagonist (CGRP_8-37) on psoriasis-like dermatitis in IMQ-treated mice.

RESULTS

BTX-B injection significantly suppressed PSI score and reduced the number of CD4⁺ T cells, CD11c⁺ dendritic cells, and the production of IL-17A/F in the lesional skin. The expressions of PGP9.5⁺ nerve fibers and neuropeptides (SP, CGRP) were also significantly reduced following BTX-B injection. Additionally, CGRP antagonist also suppressed the development of IMQ-induced psoriasis-like dermatitis in mice.

CONCLUSION

The suppression of neuropeptide secretion in the skin by BTX injection might inhibit nerve elongation, the infiltration of immune cells, as well as IL-17 production, resulting in the improvement of psoriasis. Neuropeptide inhibitor could also be applied to the treatment of psoriasis.