Effect of extracorporeal shock wave therapy on keratinocytes derived from human hypertrophic scars

Extracorporeal Shock Wave Therapy for the Treatment of Musculoskeletal Pain: A Narrative Review

Extracorporeal shock waves are high-intensity mechanical waves (500-1000 bar) of a microsecond duration with a morphology characterized by a rapid positive phase followed by a negative phase.

BACKGROUND

Extracorporeal shock waves have been used for pain treatment for various sub-acute and chronic musculoskeletal (MSK) problems since 2000. The aim of this article is to update information on the role of extracorporeal shock wave therapy (ESWT) in the treatment of various pathologies that cause MSK pain.

METHODS

Given that in the last two years, articles of interest (including systematic reviews and meta-analyses) have been published on less known indications, such as low back pain, nerve entrapments, osteoarthritis and bone vascular diseases, a literature search was conducted in PubMed, the Cochrane Database, EMBASE, CINAHL and PEDro, with the aim of developing a narrative review of the current literature on this topic. The purposes of the review were to review possible new mechanisms of action, update the level of evidence for known indications and assess possible new indications that have emerged in recent years.

RESULTS

Although extracorporeal shock waves have mechanical effects, their main mechanism of action is biological, through a phenomenon called mechanotransduction. There is solid evidence that supports their use to improve pain in many MSK pathologies, such as different tendinopathies (epicondylar, trochanteric, patellar, Achilles or calcific shoulder), plantar fasciitis, axial pain (myofascial, lumbar or coccygodynia), osteoarthritis and bone lesions (delayed union, osteonecrosis of the femoral head, Kienbock's disease, bone marrow edema syndrome of the hip, pubis osteitis or carpal tunnel syndrome). Of the clinical indications mentioned in this review, five have a level of evidence of 1+, eight have a level of evidence of 1-, one indication has a level of evidence of 2- and two indications have a level of evidence of 3.

CONCLUSIONS

The current literature shows that ESWT is a safe treatment, with hardly any adverse effects reported. Furthermore, it can be used alone or in conjunction with other physical therapies such as eccentric strengthening exercises or static stretching, which can enhance its therapeutic effect.

Effect of Hypertrophic Scar Fibroblast-Derived Exosomes on Keratinocytes of Normal Human Skin

Epidermal keratinocytes are highly activated, hyper-proliferated, and abnormally differentiated in the post-burn hypertrophic scar (HTS); however, the effects of scar fibroblasts (SFs) on keratinocytes through cell-cell interaction in HTS remain unknown. Here, we investigated the effects of HTSF-derived exosomes on the proliferation and differentiation of normal human keratinocytes (NHKs) compared with normal fibroblasts (NFs) and their possible mechanism to provide a reference for clinical intervention of HTS. Fibroblasts were isolated and cultured from HTS and normal skin. Both HTSF-exosomes and NF-exosomes were extracted via a column-based method from the cell culture supernatant. NHKs were treated for 24 or 48 h with 100 μg/mL of cell-derived exosomes. The expression of proliferation markers (Ki-67 and keratin 14), activation markers (keratins 6, 16, and 17), differentiation markers (keratins 1 and 10), apoptosis factors (Bax, Bcl2, caspase 14, and ASK1), proliferation/differentiation regulators (p21 and p27), and epithelial-mesenchymal transition (EMT) markers (E-cadherin, N-cadherin, and vimentin) was investigated. Compared with NF-exosomes, HTSF-exosomes altered the molecular pattern of proliferation, activation, differentiation, and apoptosis, proliferation/differentiation regulators of NHKs, and EMT markers differently. In conclusion, our findings indicate that HTSF-derived exosomes may play a role in the epidermal pathological development of HTS.

Extracorporeal Shock Wave Therapy for Hypertrophic Scars

Background  Hypertrophic scars cause aesthetic concerns and negatively affect the quality of life. A gold standard treatment for hypertrophic scars has not been established due to various responses of modalities. Extracorporeal shock wave therapy (ESWT) is a noninvasive and affects scar remodeling by fibroblast regulation. This study investigated the effectiveness of ESWT for hypertrophic scars.

Methods  Twenty-nine patients were enrolled. All patients underwent ESWT once a week for 6 consecutive weeks. Their scars were assessed using the Patient and Observer Scar Assessment Scale (POSAS), erythema index, melanin index, and scar pliability before treatment and again 4 weeks after treatment completion.

Results  Thirty-four hypertrophic scars in this study had persisted for between 6 months and 30 years. Most scars developed after surgical incision (55.88%). The chest and upper extremities were the predominant areas of occurrence (35.29% each). Most of the POSAS subscales and total scores were significantly improved 4 weeks after treatment ( p  < 0.05). Furthermore, the pain, itching, and pigmentation subscale were improved. The pliability, melanin index, and erythema index were also improved, but without significance. The patients were satisfied with the results and symptoms alleviation, although subjective score changes were insignificant. No serious adverse events were found. The patients reported pruritus in 62.5% and good pain tolerance in 37.5%. Subgroup analyses found no differences in scar etiologies or properties at different parts of the body.

Conclusion  The ESWT is a modality for hypertrophic scar treatment with promising results. Most of POSAS subscales were significantly improved.

Safety and efficacy of treating post-burn pathological scars with extracorporeal shock wave therapy: A meta-analysis of randomised controlled trials

The clinical application of shockwave therapy has expanded to the treatment of pathological scars. The objective of this systematic review and meta-analysis is to quantitatively evaluate the efficacy and safety of extracorporeal shockwave therapy combined with comprehensive rehabilitation therapy on post-burn pathological scars compared to comprehensive rehabilitation therapy alone. The randomised controlled trials of extracorporeal shockwave therapy for post-burn pathological scars published in English and Chinese languages before October 2021 were included. The methodological quality and risk of bias of the selected articles were assessed with the Cochrane Collaboration's 'risk of bias' tool. RevMan software was applied for data analysis. This is the first systematic review and meta-analysis considering the effectiveness and safety of extracorporeal shockwave therapy on post-burn pathological scars. And nine randomised controlled trials involving 422 patients were included in this meta-analysis. The meta-analysis results showed that, compared with comprehensive rehabilitation therapy alone, extracorporeal shockwave therapy combined with comprehensive rehabilitation therapy was more effective in relieving pain (standardized mean difference [SMD] = -0.59, 95% confidence interval [CI]: [-0.87 to -0.31], p < 0.0001) and pruritus related to pathological scars (SMD = -0.94; 95% CI: [-1.25 to -0.63], p = 0.004), improving scars' appearance (SMD = -1.78, 95% CI: [-3.37 to -0.19], p = 0.03) and elasticity (SMD = 0.25, 95% CI: [0.29-0.21], p < 0.00001), decreasing scars thickness (SMD = -0.13, 95% CI: [-0.25 to -0.01], p = 0.04) and promoting the maturation status of scars (SMD = -2.86, 95% CI: [-3.96 to -1.76], p < 0.00001). There were no reported serious adverse events during and after extracorporeal shockwave therapy in the included studies. Available data preliminarily suggested that the combination of extracorporeal shockwave therapy and comprehensive rehabilitation therapy had better therapeutic effect on post-burn pathological scars than comprehensive rehabilitation therapy alone, without obvious side effects. However, further clinical well-controlled randomised controlled trials are needed. Systematic review registration ID: PROSPERO CRD42022297573.

Extracorporeal Shock Wave Therapy Improves In Vitro Formation of Multilayered Epithelium of Oral Mucosa Equivalents

Oral mucosa is used in various surgical fields as a graft for the reconstruction of tissue defects. Tissue engineering of oral mucosa equivalents using autologous cells represents a suitable less burdensome alternative. The survival of the multilayered epithelium is essential for the functionality of the tissues in vivo. To ensure its functionality after transplantation, mucosa equivalents in vitro were subjected to extracorporeal shock wave therapy (ESWT) to determine whether this treatment stimulated the formation and differentiation of the epithelium. Mucosa equivalents treated with ESWT were examined for cellular metabolic activity using AlamarBlue^TM assay. The formation of vascular structures, basement membrane, and multilayered epithelium were examined using confocal fluorescence microscopy and immunohistochemistry. The potential ingrowth in vivo was simulated using the chorioallantoic membrane model (CAM assay) in ovo. ESWT on culture day 19 of oral mucosa equivalents resulted in slightly increased cellular metabolic activity. The in vitro development of basement membrane and multilayer epithelium was stimulated by ESWT. Additionally, in the CAM assay, ESWT led to a more pronounced multilayered epithelium. Thus, ESWT stimulated the formation of a more distinct and differentiated multilayered epithelium of oral mucosa equivalents in vitro and might increase the chance of efficient ingrowth, survival, and functionality of tissue equivalents in vivo.

Extracorporeal Shock Wave Therapy Combined with Complex Decongestive Therapy in Patients with Breast Cancer-Related Lymphedema: A Systemic Review and Meta-Analysis

Breast cancer-related lymphedema (BCRL) is one of the most significant complications seen after surgery. Several studies demonstrated that extracorporeal shock wave therapy (ESWT), in addition to conventional complex decongestive therapy (CDT), had a positive effect on BCRL in various aspects. The systematic review and meta-analysis aim to explore the effectiveness of ESWT with or without CDT on BRCL patients. We searched PubMed, Embase, PEDro, Cochrane Library Databases, and Google Scholar for eligible articles and used PRISMA2020 for paper selection. Included studies were assessed by the PEDro score, Modified Jadad scale, STROBE assessment, and GRADE framework for the risk of bias evaluation. The primary outcomes were the volume of lymphedema and arm circumference. Secondary outcome measures were skin thickness, shoulder joint range of motion (ROM), and an impact on quality-of-life questionnaire. Studies were meta-analyzed with the mean difference (MD). Eight studies were included in the systemic review and four in the meta-analysis. In summary, we found that adjunctive ESWT may significantly improve the volume of lymphedema (MD = -76.44; 95% CI: -93.21, -59.68; p < 0.00001), skin thickness (MD = -1.65; 95% CI: -3.27, -0.02; p = 0.05), and shoulder ROM (MD = 7.03; 95% CI: 4.42, 9.64; p < 0.00001). The evidence level was very low upon GRADE appraisal. ESWT combined with CDT could significantly improve the volume of lymphedema, skin thickness, and shoulder ROM in patients with BCRL. There is not enough evidence to support the use of ESWT as a replacement for CDT. This study was registered with PROSPERO: CRD42021277110.