Botulinum toxin for the prevention and healing of wound scars: A systematic review of the literature

Early postoperative interventions in the prevention and management of thyroidectomy scars

Thyroidectomy scars, located on the exposed site, can cause distress in patients. Owing to the cosmetic importance of thyroidectomy scars, many studies have been conducted on its prevention and treatment. Scar formation factors mainly include inflammatory cell infiltration, angiogenesis, fibroblast proliferation, secretion of cytokines such as transforming growth factor (TGF)-β1, and mechanical tension on the wound edges. Anti-scar methods including topical anti-scar agents, skin tension-bearing devices, and local injections of botulinum toxin, as well as lasers and phototherapies, that target these scar formation factors have been developed. However, current studies remain fragmented, and there is a lack of a comprehensive evaluation of the impacts of these anti-scar methods on treating thyroidectomy scars. Early intervention is a crucial but often neglected key to control hyperplastic thyroidectomy scars. Therefore, we review the currently adopted early postoperative strategies for thyroidectomy scar reduction, aiming to illustrate the mechanism of these anti-scar methods and provide flexible and comprehensive treatment selections for clinical physicians to deal with thyroidectomy scars.

Successful Topical Application of Botulinum Toxin After Microneedling Versus Microneedling Alone for the Treatment of Atrophic Post Acne Scars: A Prospective, Split-face, Controlled Study

BACKGROUND

Acne scars are a source of cosmetic concern for most of the patients.

OBJECTIVE

We sought to compare the clinical efficacy and safety of topical botulinum toxin A (BTX-A) application immediately after microneedling (Mn) versus Mn with saline in the treatment of atrophic acne scars.

METHODS

Forty patients with atrophic acne scars (rolling, boxcar, and mixed types) were enrolled in a split-face study; microneedling was performed on both sides of the face followed by an application of topically diluted botulinum toxin on one side (Side A) and saline on the other (Side B) for two sessions both two weeks apart. Evaluation was done at baseline, two and four weeks after the session. Follow-up was performed after six months. The assessments included blinded clinical assessment and patient's satisfaction.

RESULTS

After the treatment, acne scars in (Side A) showed 70 percent overall improvement versus zero percent in Side B (P<0.0001). A statistically highly significant reduction of acne scars severity occurred in (Side A) (P=0.0008). Patient's satisfaction was higher in (Side A) (P<0.0001). No serious side effects were reported.

CONCLUSION

Microneedling delivery of BTX-A could be simple, safe, and innovative modality improving the appearance and decrease the depth of atrophic acne scars.

The Role of Extracellular Matrix in Skin Wound Healing

Impaired wound healing is one of the unsolved problems of modern medicine, affecting patients’ quality of life and causing serious economic losses. Impaired wound healing can manifest itself in the form of chronic skin wounds or hypertrophic scars. Research on the biology and physiology of skin wound healing disorders is actively continuing, but, unfortunately, a single understanding has not been developed. The attention of clinicians to the biological and physiological aspects of wound healing in the skin is necessary for the search for new and effective methods of prevention and treatment of its consequences. In addition, it is important to update knowledge about genetic and non-genetic factors predisposing to impaired wound healing in order to identify risk levels and develop personalized strategies for managing such patients. Wound healing is a very complex process involving several overlapping stages and involving many factors. This thematic review focuses on the extracellular matrix of the skin, in particular its role in wound healing. The authors analyzed the results of fundamental research in recent years, finding promising potential for their transition into real clinical practice.

The Roles of Inflammation in Keloid and Hypertrophic Scars

The underlying mechanisms of wound healing are complex but inflammation is one of the determining factors. Besides its traditional role in combating against infection upon injury, the characteristics and magnitude of inflammation have dramatic impacts on the pathogenesis of scar. Keloids and hypertrophic scars are pathological scars that result from aberrant wound healing. They are characterized by continuous local inflammation and excessive collagen deposition. In this review, we aim at discussing how dysregulated inflammation contributes to the pathogenesis of scar formation. Immune cells, soluble inflammatory mediators, and the related intracellular signal transduction pathways are our three subtopics encompassing the events occurring in inflammation associated with scar formation. In the end, we enumerate the current and potential medicines and therapeutics for suppressing inflammation and limiting progression to scar. Understanding the initiation, progression, and resolution of inflammation will provide insights into the mechanisms of scar formation and is useful for developing effective treatments.

The Expanding Therapeutic Utility of Botulinum Neurotoxins

Botulinum neurotoxin (BoNT) is a major therapeutic agent that is licensed in neurological indications, such as dystonia and spasticity. The BoNT family, which is produced in nature by clostridial bacteria, comprises several pharmacologically distinct proteins with distinct properties. In this review, we present an overview of the current therapeutic landscape and explore the diversity of BoNT proteins as future therapeutics. In recent years, novel indications have emerged in the fields of pain, migraine, overactive bladder, osteoarthritis, and wound healing. The study of biological effects distal to the injection site could provide future opportunities for disease-tailored BoNT therapies. However, there are some challenges in the pharmaceutical development of BoNTs, such as liquid and slow-release BoNT formulations; and, transdermal, transurothelial, and transepithelial delivery. Innovative approaches in the areas of formulation and delivery, together with highly sensitive analytical tools, will be key for the success of next generation BoNT clinical products.

Antipruritic Effects of Botulinum Neurotoxins

This review explores current evidence to demonstrate that botulinum neurotoxins (BoNTs) exert antipruritic effects. Both experimental and clinical conditions in which botulinum neurotoxins have been applied for pruritus relief will be presented and significant findings will be highlighted. Potential mechanisms underlying antipruritic effects will also be discussed and ongoing challenges and unmet needs will be addressed.

New Uses of AbobotulinumtoxinA in Aesthetics

BotulinumtoxinA (BoNT-A) is now widely established for the main approved indication of reducing glabellar lines, and is also widely used off-label to improve the appearance of wrinkles and lines in other parts of the face. The number of aesthetic procedures continues to increase as the patient population becomes more diverse, in particular with increasing numbers of people of color and men. Further developments in treatment may continue to expand the audience for BoNT-A by making procedures more comfortable and by delivering a more natural, less static appearance. These may be achieved through use of combinations of BoNT-A with other aesthetic procedures, tailoring the dose of toxin to the patient's muscle mass or by using novel injection and application techniques. Beyond amelioration of facial lines, encouraging results have been seen with the use of BoNT-A to improve the appearance of hypertrophic and keloid scars and even to prevent them. Studies have been conducted with scars in various parts of the body and further research is ongoing. Dermatological and other medical uses for BoNT-A are also active areas of research. Injections of BoNT-A have been shown to reduce signs and symptoms of acne, rosacea, and psoriasis, to reduce neuromuscular pain, and to bring about significant improvements in a number of rare diseases that are caused or exacerbated by hyperhidrosis. This paper reviews these new uses for BoNT-A, looking at the rationale for their use and discussing the results of published case studies and clinical trials. These areas have shown great promise to date, but more and larger clinical studies will be required before these treatments become a clinical reality. To this end details are also provided of clinical trials currently listed in the main clinical trials database to highlight research areas of particular interest.