Recent Advances in Scar Biology

Prospects for Use of Botulinum Toxin Type A for Prevention of Hypertrophic and Keloid Scars after Surgeries

Objective  To evaluate the possibility of improving and preventing the formation of postoperative hypertrophic and keloid scars using botulinum toxin type A (BTA). Materials and Methods  Scientific articles published in English have been systematically screened in PubMed/MEDLINE database over the entire period. The following information about the studies was analyzed: first author surname; year of publication; number of patients; average age; scar location; dosage of the drug administered; follow-up duration; scar assessment methods; results, incidence of hypertrophic and keloid scars formation. The odds ratio and 95% confidence interval were calculated for each of the estimated parameters. The statistical heterogeneity of publications assessed using the criteria of chi-square test and I 2 . The differences were considered significant at p  < 0.05. Results  A total of 18 prospective randomized studies were selected for evaluation, containing data on the use of BTA in 363 cases. Patients receiving botulinum toxin had a lower Vancouver scar scale index, higher visual analog scale index, and higher Stony Brook scar evaluation scale score. The use of BTA reduces the risk of perceptible scar formation, the incidence of hypertrophic and keloid scars. Conclusion  The use of BTA to obtain imperceptible scar and prevent hypertrophic and keloid postoperative scars demonstrates good prospects. However, there is no consensus regarding the pathophysiological mechanisms underlying the positive effect of BTA on the prevention of hypertrophic and keloid scars.

Progress on the pathological tissue microenvironment barrier-modulated nanomedicine

Imbalance in the tissue microenvironment is the main obstacle to drug delivery and distribution in the human body. Before penetrating the pathological tissue microenvironment to the target site, therapeutic agents are usually accompanied by three consumption steps: the first step is tissue physical barriers for prevention of their penetration, the second step is inactivation of them by biological molecules, and the third step is a cytoprotective mechanism for preventing them from functioning on specific subcellular organelles. However, recent studies in drug-hindering mainly focus on normal physiological rather than pathological microenvironment, and the repair of damaged physiological barriers is also rarely discussed. Actually, both the modulation of pathological barriers and the repair of damaged physiological barriers are essential in the disease treatment and the homeostasis maintenance. In this review, we present an overview describing the latest advances in the generality of these pathological barriers and barrier-modulated nanomedicine. Overall, this review holds considerable significance for guiding the design of nanomedicine to increase drug efficacy in the future.

Immune cells and associated molecular markers in dermal fibrosis with focus on raised cutaneous scars

Raised dermal scars including hypertrophic, and keloid scars as well as scalp-associated fibrosing Folliculitis Keloidalis Nuchae (FKN) are a group of fibrotic raised dermal lesions that mostly occur following cutaneous injury. They are characterized by increased extracellular matrix (ECM) deposition, primarily excessive collagen type 1 production by hyperproliferative fibroblasts. The extent of ECM deposition is thought to be proportional to the severity of local skin inflammation leading to excessive fibrosis of the dermis. Due to a lack of suitable study models, therapy for raised dermal scars remains ill-defined. Immune cells and their associated markers have been strongly associated with dermal fibrosis. Therefore, modulation of the immune system and use of anti-inflammatory cytokines are of potential interest in the management of dermal fibrosis. In this review, we will discuss the importance of immune factors in the pathogenesis of raised dermal scarring. The aim here is to provide an up-to-date comprehensive review of the literature, from PubMed, Scopus, and other relevant search engines in order to describe the known immunological factors associated with raised dermal scarring. The importance of immune cells including mast cells, macrophages, lymphocytes, and relevant molecules such as cytokines, chemokines, and growth factors, antibodies, transcription factors, and other immune-associated molecules as well as tissue lymphoid aggregates identified within raised dermal scars will be presented. A growing body of evidence points to a shift from proinflammatory Th1 response to regulatory/anti-inflammatory Th2 response being associated with the development of fibrogenesis in raised dermal scarring. In summary, a better understanding of immune cells and associated molecular markers in dermal fibrosis will likely enable future development of potential immune-modulated therapeutic, diagnostic, and theranostic targets in raised dermal scarring.

Application of Biomedical Microspheres in Wound Healing

Tissue injury, one of the most common traumatic injuries in daily life, easily leads to secondary wound infections. To promote wound healing and reduce scarring, various kinds of wound dressings, such as gauze, bandages, sponges, patches, and microspheres, have been developed for wound healing. Among them, microsphere-based tissue dressings have attracted increasing attention due to the advantage of easy to fabricate, excellent physicochemical performance and superior drug release ability. In this review, we first introduced the common methods for microspheres preparation, such as emulsification-solvent method, electrospray method, microfluidic technology as well as phase separation methods. Next, we summarized the common biomaterials for the fabrication of the microspheres including natural polymers and synthetic polymers. Then, we presented the application of the various microspheres from different processing methods in wound healing and other applications. Finally, we analyzed the limitations and discussed the future development direction of microspheres in the future.

The objective evaluation of triamcinolone acetonide efficacy in keloids management using Antera3D® imaging system

Background

Keloids are pathological scars characterized by nodular fibrous tissue that extends beyond the border of initial damage. These lesions do not spontaneously regress and can cause cosmetic disfigurements and functional disabilities. IntraLesional Injection of Triamcinolone Acetonide (ILITA), alone or in combination with other therapy, is one of the first-line treatment modalities. In this study the authors evaluated the objective efficacy of ILITA treatment in keloids management using this new imaging system.

Materials and Methods

37 patients with 45 keloid scars were treated with intralesional injection of triamcinolone acetonide (TAC) 20 mg/ml at an interval of three weeks. Antera3D® camera took the images and dates of the treated area in each patient, before the treatment (T0) and at three weeks after the last injection (T1). The system processed the levels of color, elevations, melanin and hemoglobin expression. All the scars were also evaluated, at the same times, by validated Vancouver Scar Scale (VSS). Comparison of the variables was performed using a Wilcoxon signed-rank test with a p < 0.05.

Results

At T0, mean VSS score was 8.67 ± 1.35 which reduced to 3.62 ± 1.72 at final follow up. Antera3D® scores were statistically significant differences in color (8.14 ± 2.41 vs 9.54 ± 1.81), protrusion (381.3 ± 15.6 vs 198.6 ± 21.3), melanin (0.53 ± 0.02 vs 0.62 ± 0.2) and hemoglobin (1.26 ± 0.41 vs 2.21 ± 0.41) expression levels after the treatment.

Conclusions

In our clinical trial, the data results demonstrated that ILITA seems to be effective in reducing keloid dimensions and symptoms such as itching and pain, even if the treatment has local minimal adverse effects such as pain, telangiectasias and atrophy.

Lay Summary

Keloids are pathological scars characterized by nodular fibrous tissue that extends beyond the border of initial damage. Large keloids can cause cosmetic disfigurements and functional disabilities that affect quality of life. In literature, several treatment approaches have been described but, to date, no single method is considered superior. The International Advisory Panel on Scar Management recommended the use of intralesional steroid injections for keloids treatment. The efficacy of treatment may be evaluated with subjective scale; as no one can guarantee an objective evaluation. To eliminate the observer and/or patient factors, and to obtain a reliable, consistent, feasible, valid and objective evaluation a skin analysis camera system called Antera3D® (Miravex, Dublin, Ireland) can be used.In this study the authors evaluated the objective efficacy of triamcinolone acetonide treatment in keloids management using this imaging system. In this series, for Antera3D® scores there were statistically significant differences in color, protrusion, melanin and hemoglobin expression levels before and after treatment. The device directly shows the treatment changes, measured objectively and accurately, without bias of traditional evaluation scoring scale.Antera3D® system guarantees an objective evaluation of effectiveness of scar treatment enabling clinicians to modulate the therapy according to the scores registered.

Integrated PPI- and WGCNA-retrieval of hub gene signatures for soft substrates inhibition of human fibroblasts proliferation and differentiation

Fibroblasts (FBs) are the most important functional cells in the process of wound repair, and their functions can be activated by different signals at the pathological site. Although wound repair is associated with microenvironmental stiffness, the effect of matrix stiffness on FBs remains elusive. In this study, TGF-β1 was used to mimic the fibrotic environment under pathological conditions. We found that the soft substrates made FBs slender compared with tissue culture plastic, and the main altered biological function was the inhibition of proliferation and differentiation ability. Through PPI and WGCNA analysis, 63 hub genes were found, including GADD45A, CDKN3, HIST2H3PS2, ACTB, etc., which may be the main targets of soft substrates affecting the proliferation and differentiation of FBs. Our findings not only provide a more detailed report on the effect of matrix stiffness on the function of human skin FBs, but also may provide new intervention ideas for improving scars and other diseases caused by excessive cell proliferation, with potential clinical application prospects.

Photobiomodulation therapy with an 830-nm light-emitting diode for the prevention of thyroidectomy scars: a randomized, double-blind, sham device-controlled clinical trial

This randomized, double-blind, and sham device-controlled trial aimed to evaluate the efficacy and safety of home-based photobiomodulation therapy using an 830-nm light-emitting diode (LED)-based device for the prevention of and pain relief from thyroidectomy scars. Participants were randomized to receive photobiomodulation therapy using an LED device or a sham device without an LED from 1 week postoperatively for 4 weeks. Scars were assessed using satisfaction scores, the numeric rating scale (NRS) score for pain, Global Assessment Scale (GAS), and Vancouver Scar Scale (VSS) scores. The scars were also assessed using a three-dimensional (3D) skin imaging device to detect color, height, pigmentation, and vascularity. Assessments were performed at the 1-, 3-, and 6-month follow-ups. Forty-three patients completed this trial with 21 patients in the treatment group and 22 patients in the control group. The treatment group showed significantly higher patient satisfaction and GAS scores and lower NRS and VSS scores than the control group at 6 months. Improvements in color variation, height, pigmentation, and vascularity at 6 months were greater in the treatment group than in the control group, although the differences were not significant. In conclusion, early application of 830-nm LED-based photobiomodulation treatment significantly prevents hypertrophic scar formation and reduces postoperative pain without noticeable adverse effects.

Important role of mechanical microenvironment on macrophage dysfunction during keloid pathogenesis

Keloid is considered as a tumor-like skin disease with multiple aetiologies including immunological factors and mechanical microenvironment. Macrophages are plastic and diverse immune cells that play a critical role in maintaining tissue homeostasis by removing dead cells, debris, pathogens and repairing tissues after inflammation. The imbalance of M1/M2 macrophages and disturbances in macrophage functions can steer the progression of chronic inflammation and lead to the development of pathological fibrosis in keloid disease. Recently, it has been shown that macrophages are sensitive to mechanical signals, especially stretching tension and tissue stiffness, which can determine macrophage polarization and functions. Higher stretching tension is known to be an important pathogenic factor of keloid, and the formation of keloid will lead to an increase in tissue stiffness. As little is known about the underlying reasons of macrophages dysfunction in keloid, an understanding of how the mechanical microenvironment interacting with macrophages and affecting their behaviours may help provide mechanism insights into keloid pathogenesis. We thus hypothesize that the synergistic effect of stretching tension and matrix stiffness may contribute to the major pathophysiological niche attributes of macrophages' in vivo mechanical microenvironment in keloids. These mechanism insights of how macrophages sense and respond to their mechanical microenvironment would propel the development of novel strategies for keloid treatment.

Focus on the Primary Prevention of Intrauterine Adhesions: Current Concept and Vision

Intrauterine adhesion (IUA), and its severe form Asherman syndrome (Asherman’s syndrome), is a mysterious disease, often accompanied with severe clinical problems contributing to a significant impairment of reproductive function, such as menstrual disturbance (amenorrhea), infertility or recurrent pregnancy loss. Among these, its correlated infertility may be one of the most challenging problems. Although there are many etiologies for the development of IUA, uterine instrumentation is the main cause of IUA. Additionally, more complicated intrauterine surgeries can be performed by advanced technology, further increasing the risk of IUA. Strategies attempting to minimize the risk and reducing its severity are urgently needed. The current review will expand the level of our knowledge required to face the troublesome disease of IUA. It is separated into six sections, addressing the introduction of the normal cyclic endometrial repairing process and its abruption causing the formation of IUA; the etiology and prevalence of IUA; the diagnosis of IUA; the classification of IUA; the pathophysiology of IUA; and the primary prevention of IUA, including (1) delicate surgical techniques, such as the use of surgical instruments, energy systems, and pre-hysteroscopic management, (2) barrier methods, such as gels, intrauterine devices, intrauterine balloons, as well as membrane structures containing hyaluronate–carboxymethylcellulose or polyethylene oxide–sodium carboxymethylcellulose as anti-adhesive barrier.

Management of Unsatisfactory Postoperative Double Eyelid With Intralesional Corticosteroid Injection

Purpose: The present study was designed to observe the curative effect of early intralesional corticosteroid injection to treat unsatisfactory double eyelid.

Methods: This retrospective, observational study included 30 female patients (age 22–35 years) receiving intralesional corticosteroid injection after complaining about the unsatisfactory double eyelid post-transcutaneous upper eyelid blepharoplasty. The postoperative double eyelid anomalies included multiple folds, sunken eyelids, and severe postoperative eyelid edema. The evaluation of the clinical effect was based on the bilateral symmetry of the eyelid, the placement of the lid fold, the radian of the double eyelid, and the extent of the swelling and depression.

Results: Multiple folds were observed in 11 (36.67%) patients, sunken eyelids in 9 (30.00%) patients, and severe postoperative eyelid edema in 10 (33.33%) patients. Among them, 17 (56.67%) patients received one intralesional injection and experienced significant improvement in the eyelid, while 8 (26.67%) accepted another injection at 1 month after the first injection and achieved marked improvement. The remaining 5 (16.67%) patients were dissatisfied with the results and might need further repair surgery: 2 patients had multiple folds, 2 showed postoperative edema, and 1 presented sunken eyelids. None of the patients reported any adverse reactions.

Conclusion: Intralesional corticosteroid injection for the correction of the postoperative unsatisfactory double eyelid is safe and convenient, and provides a novel method for early intervention.

Programmable immune activating electrospun fibers for skin regeneration

Immune cells play a crucial regulatory role in inflammatory phase and proliferative phase during skin healing. How to programmatically activate sequential immune responses is the key for scarless skin regeneration. In this study, an "Inner-Outer" IL-10-loaded electrospun fiber with cascade release behavior was constructed. During the inflammatory phase, the electrospun fiber released a lower concentration of IL-10 within the wound, inhibiting excessive recruitment of inflammatory cells and polarizing macrophages into anti-inflammatory phenotype "M2c" to suppress excessive inflammation response. During the proliferative phase, a higher concentration of IL-10 released by the fiber and the anti-fibrotic cytokines secreted by polarized "M2c" directly acted on dermal fibroblasts to simultaneously inhibit extracellular matrix overdeposition and promote fibroblast migration. The "Inner-Outer" IL-10-loaded electrospun fiber programmatically activated the sequential immune responses during wound healing and led to scarless skin regeneration, which is a promising immunomodulatory biomaterial with great potential for promoting complete tissue regeneration.

Tomotherapy as an Alternative Irradiative Treatment for Complicated Keloids

The aim of this study was to investigate the treatment of complicated keloids with helical tomotherapy (HT) and electron beam radiotherapy. From July 2018 to September 2018, 11 patients with 23 keloid lesions treated with HT were enrolled. Additionally, 11 patients with 20 lesions treated with electron beam radiotherapy in the same period were enrolled. Patients in both groups were treated within 24 h after surgical excision of the keloid lesion with 13.5 Gy in three consecutive daily fractions. The median follow-up period was 15 months. The local control rate was 91.3% and 80% in the HT group and the electron beam group, respectively. No acute adverse effects were observed in either group, but most patients exhibited pigmentation. No radiation-induced cancer occurred in these patients up to the time of this report. Pain and pruritus improved for all patients and more obviously for three patients with complicated keloids treated with HT. The measured surface dose was 103.7–112.5% and 92.8–97.6% of the prescribed dose in the HT group and the electron beam group, respectively. HT can be considered an alternative in cases where it is not feasible to use multiple electron fields, due to encouraging clinical outcomes.

Efficacy of Applying Hyaluronic Acid Gels in the Primary Prevention of Intrauterine Adhesion after Hysteroscopic Myomectomy: A Meta-Analysis of Randomized Controlled Trials

Intrauterine adhesion (IUA), which mainly occurs after intrauterine surgery or an inflammatory process, is an important but often neglected condition in women of reproductive age. The presentation of IUA varies greatly, ranging from symptom-free to severe, with amenorrhea or infertility. With much advanced development of intrauterine instruments, more intrauterine diseases can be successfully cured by hysteroscopic surgery. Among these, submucosal myoma is one of the best examples. Submucosal myomas are often related to abnormal bleeding, anemia, and possible infertility or miscarriage. However, submucosal myoma after hysteroscopic myomectomy may be complicated by IUA in various grades of severity, and its incidence and prevalence might be nearly one-quarter to one-third of patients, suggesting an urgent need for efforts to decrease the risk of developing IUA after hysteroscopic myomectomy. Many strategies have been reported to be useful for this purpose, and intrauterine application of anti-adhesive gels, such as polyethylene oxide–sodium carboxymethylcellulose (PEO-NaCMC) or auto-crosslinked hyaluronic acid (ACHA), has become increasingly popular in routine clinical practice. This meta-analysis is aimed at investigating the effect of ACHA on the primary prevention of IUA formation after hysteroscopic myomectomy. A pooled analysis of three studies (hysteroscopic surgeries for fibroids, polyps, and septum) including 242 women showed that using PEO-NaCMC or ACHA gel decreased the IUA rate with an odds ratio (OR) of 0.364 (95% confidence interval (CI) 0.189–0.703, p = 0.03). Pooled analysis of two studies that limited the use of ACHA in 119 women showed that the application of ACHA gel for the primary prevention of IUA in patients after hysteroscopic myomectomy led to a statistically significant reduction of the development of IUA postoperatively (OR 0.285, 95% CI 0.116–0.701, p = 0.006). All of this suggests that the use of ACHA gel in patients after hysteroscopic myomectomy could significantly reduce de novo IUA, although more evidence is needed.

Genetically modified adipose-derived stem cells with matrix metalloproteinase 3 promote scarless cutaneous repair

Adipose-derived stem cells (ASCs) possess strong regenerative potencies and have been used to improve wound healing in animal models and clinical studies. However, the use of ASCs on scarless wound healing is not satisfactory. Matrix metalloproteinase 3 (MMP-3) is involved in extracellular matrix (ECM) remolding and scar formation. We aimed to investigate the effect of ASCs stable expressing MMP-3 (ASCs-MMP-3) on wound healing and scarring. A cutaneous wound healing animal model was used to assess the effect of ASCs and ASCs-MMP-3 on wound healing and scar formation. The target protein levels in the wound tissues were determined by western blot assay. Our results demonstrated that ASCs alone promoted wound healing but had a negligible effect on reducing scarring. ASCs-MMP-3 not only possessed the ability of ASCs to speed up wound healing, but also incorporated the capability of MMP-3 to reduce scaring. Overexpressing of MMP-3 decreased the collagen I, transforming growth factor (TGF)-β1, and α-smooth muscle actin (α-SMA) levels and enhanced collagen III and TGF-β3 levels which contributed to reducing scar formation. Our studies suggested that ASCs-MMP-3 is a potential candidate for developing effective therapeutic strategies for scarless wound healing.