Extracorporeal shock wave treatment improves incisional wound healing in diabetic rats

Could radial extracorporeal shock wave therapy have an effect on wound healing in clinical practice by creating genotoxic damage? An in vitro study in mouse fibroblasts

Objectives: This study aims to evaluate wound healing effects of in vitro radial extracorporeal shock wave (rESW) application on mouse fibroblasts and whether the cytotoxic effect of extracorporeal shock wave (ESW) was due to a possible genotoxic effect.

Patients and methods: After creating an in vitro wound healing model in L929 mouse fibroblast culture, fibroblasts were stimulated with a frequency of 3 Hz, and 100, 250, 500, 1,000 and 1,500 pulses shock waves were applied. Energy flux densities ranging from 0.01 to 0.23 mJ/mm2 (14.3 MPa) at a constant pressure level of 0.5 and 1 bar were applied. Wound healing, cell viability, and genotoxicity were evaluated at 24 and 48 h.

Results: All shot numbers for both pressures significantly reduced cell viability (p<0.05). For both 0.5 and 1 bar pressures, in both intervals, the rate of wound healing decreased, regardless of the number of shots (p<0.05). In vitro genotoxic damage was detected at both 0.5 and 1 bar pressures, in both time intervals, regardless of the number of shots. The genotoxic damage increased from 24 to 48 h.

Conclusion: The study results suggest that, when ESWT is applied in this in vitro experimental setup, cell viability decreases and wound healing is delayed under all conditions. Furthermore, genotoxic damage can be prevented by using shots below 1,000 pulses. Therefore, while investigating the therapeutic effect of ESW therapy in vitro, the upper limit for the number of shots should be 1,000 pulses.

Mechanotransduction in Wound Healing: From the Cellular and Molecular Level to the Clinic

GENERAL PURPOSE

To review the various mechanical forces that affect fibroblasts, keratinocytes, endothelial cells, and adipocytes at the cellular and molecular level as well as scar-reducing mechanical devices currently in clinical use.

TARGET AUDIENCE

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES

After participating in this educational activity, the participant will:1. Compare and contrast the responses of various types of cells to mechanical forces.2. Identify the mechanical devices and techniques that can help restore skin integrity.

The Basic Science Behind Low-Intensity Extracorporeal Shockwave Therapy for Erectile Dysfunction: A Systematic Scoping Review of Pre-Clinical Studies

INTRODUCTION

Despite recent promising clinical results, the underlying mechanism of action of low-intensity extracorporeal shockwave therapy (Li-ESWT) for erectile dysfunction (ED) is mostly unclear and currently under investigation.

AIM

To systematically identify and evaluate evidence regarding the basic science behind Li-ESWT for ED, discuss and propose a putative mechanism of action, address the limitations, and imply insights for further investigation in the field.

METHODS

Using Cochrane's methodologic recommendations on scoping studies and systematic reviews, we conducted a systematic scoping review of the literature on experimental research regarding Li-ESWT for ED and other pathologic conditions. The initial systematic search was carried between January and November 2017, with 2 additional searches in April and August 2018. All studies that applied shockwave treatment at an energy flux density >0.25 mJ/mm² were excluded from the final analysis.

MAIN OUTCOME MEASURE

We primarily aimed to clarify the biological responses in erectile tissue after Li-ESWT that could lead to improvement in erectile function.

RESULTS

59 publications were selected for inclusion in this study. 15 experimental research articles were identified on Li-ESWT for ED and 44 on Li-ESWT for other pathologic conditions. Li-ESWT for ED seems to improve erectile function possibly through stimulation of mechanosensors, inducing the activation of neoangiogenesis processes, recruitment and activation of progenitor cells, improving microcirculation, nerve regeneration, remodeling of erectile tissue, and reducing inflammatory and cellular stress responses.

CLINICAL IMPLICATIONS

Improving our understanding of the mechanism of action of Li-ESWT for ED can help us improve our study designs, as well as suggest new avenues of investigation.

STRENGTHS & LIMITATIONS

A common limitation in all these studies is the heterogeneity of the shockwave treatment application and protocol.

CONCLUSION

Li-ESWT for ED, based on current experimental studies, seems to improve erectile function by inducing angiogenesis and reversing pathologic processes in erectile tissue. These studies provide preliminary insights, but no definitive answers, and many questions remain unanswered regarding the mechanism of action, as well as the ideal treatment protocol. Sokolakis I, Dimitriadis F, Teo P, et al. The Basic Science Behind Low-Intensity Extracorporeal Shockwave Therapy for Erectile Dysfunction: A Systematic Scoping Review of Pre-Clinical Studies. J Sex Med 2019;16:168-194.

Noncontact Phased-Array Ultrasound Facilitates Acute Wound Healing in Mice

Supplemental Digital Content is available in the text.

Background:

The authors developed a noncontact low-frequency ultrasound device that delivers high-intensity mechanical force based on phased-array technology. It may aid wound healing because it is likely to be associated with lower risks of infection and heat-induced pain compared with conventional ultrasound methods. The authors hypothesized that the microdeformation it induces accelerates wound epithelialization. Its effects on key wound-healing processes (angiogenesis, collagen accumulation, and angiogenesis-related gene transcription) were also examined.

Methods:

Immediately after wounding, bilateral acute wounds in C57BL/6J mice were noncontact low-frequency ultrasound– and sham-stimulated for 1 hour/day for 3 consecutive days (10 Hz/90.6 Pa). Wound closure (epithelialization) was recorded every 2 days as the percentage change in wound area relative to baseline. Wound tissue was procured on days 2, 5, 7, and 14 (five to six per time point) and subjected to histopathology with hematoxylin and eosin and Masson trichrome staining, CD31 immunohistochemistry, and quantitative polymerase-chain reaction analysis.

Results:

Compared to sham-treated wounds, ultrasound/phased-array–treated wounds exhibited significantly accelerated epithelialization (65 ± 27 percent versus 30 ± 33 percent closure), angiogenesis (4.6 ± 1.7 percent versus 2.2 ± 1.0 percent CD31⁺ area), and collagen deposition (44 ± 14 percent versus 28 ± 13 percent collagen density) on days 5, 2, and 5, respectively (all p < 0.05). The expression of Notch ligand delta-like 1 protein (Dll1) and Notch1, which participate in angiogenesis, was transiently enhanced by treatment on days 2 and 5, respectively.

Conclusions:

The authors’ noncontact low-frequency ultrasound phased-array device improved the wound-healing rate. It was associated with increased early neovascularization that was followed by high levels of collagen-matrix production and epithelialization. The device may expand the mechanotherapeutic proangiogenesis field, thereby helping stimulate a revolution in infected wound care.

Effects of Hair Follicle Stem Cells on Partial-Thickness Burn Wound Healing and Tensile Strength

Background:

The recent improvements in wound healing have led to new strategies in regenerative medicine. Burn wound healing is an important issue in skin regeneration and has multiple indications for stem cell therapy. HFSCs are a highly promising source of stem cells for healing use, as these cells are accessible, active and pluripotent adult stem cells.

Methods:

HFSCs of the rat whisker were isolated, cultured, and labeled with DiI. Flow cytometry method was used to detect special markers of HFSCs. Deep partial-thickness burn wound was created, and labeled HFSCs were injected around the wound bed. Wound closure was recorded via digital photographs. The inflicted rats were sacrificed at 3, 7, or 14 days post burn and used for subsequent histological and tensiometry analysis.

Results:

Our results indicated that HFSCs were positive for Nestin and CD34 markers, but negative for Kr15. Morphological and histological photographs revealed that wound closure rate was accelerated in stem cell-treated group compared with other groups. In addition, faster re-epithelialization and collagen deposition were observed. The immunohistochemical analysis suggested that CD31 expression and vascular density enhanced in the stem cell-treated group. Further, tissue tensile strength increased in HFSCs-treated rats in comparison to the control group.

Conclusion:

The present study demonstrates that HFSCs could accelerate burn wound healing as well as tensile strength in rats.

Efficacy of Biophysical Energies on Healing of Diabetic Skin Wounds in Cell Studies and Animal Experimental Models: A Systematic Review

We have systematically assessed published cell studies and animal experimental reports on the efficacy of selected biophysical energies (BPEs) in the treatment of diabetic foot ulcers. These BPEs include electrical stimulation (ES), pulsed electromagnetic field (PEMF), extracorporeal shockwave (ECSW), photo energies and ultrasound (US). Databases searched included CINAHL, MEDLINE and PubMed from 1966 to 2018. Studies reviewed include animal and cell studies on treatment with BPEs compared with sham, control or other BPEs. Information regarding the objective measures of tissue healing and data was extracted. Eighty-two studies were eventually selected for the critical appraisal: five on PEMF, four each on ES and ECSW, sixty-six for photo energies, and three about US. Based on the percentage of original wound size affected by the BPEs, both PEMF and low-level laser therapy (LLL) demonstrated a significant clinical benefit compared to the control or sham treatment, whereas the effect of US did not reveal a significance. Our results indicate potential benefits of selected BPEs in diabetic wound management. However, due to the heterogeneity of the current clinical trials, comprehensive studies using well-designed trials are warranted to confirm the results.

Efficacy of shock wave therapy on chronic diabetic foot ulcer: a single-blinded randomized controlled clinical trial

OBJECTIVE

This study was conducted to evaluate the efficacy of extracorporeal shock wave therapy (ESWT) on the healing rate, wound surface area and wound bed preparation in chronic diabetic foot ulcers (DFU).

METHODS

Thirty eight patients with 45 chronic DFU were randomly assigned into; the ESWT-group (19 patients/24 ulcers) and the control-group (19 patients/21 ulcers). Blinded therapist measured wound surface area (WSA), the percentage of reduction in the WSA, rate of healing and wound bed preparation at baseline, after the end of the interventions (W8), and at 20-week follow-up (W20). The ESWT group received shock wave therapy twice per week for a total of eight treatments. Each ulcer was received ESWT at a frequency of 100 pulse/cm(2), and energy flux density of 0.11mJ/cm(2). All patients received standardized wound care consisting of debridement, blood-glucose control agents, and footwear modification for pressure reduction.

RESULTS

The overall clinical results showed completely healed ulcers in 33.3% and 54% in ESWT-groups and 14.28% and 28.5% in the control group after intervention (W8), and at follow-up (W20) respectively. The average healing time was significantly lower (64.5 ± 8.06 days vs 81.17 ± 4.35 days, p<0.05) in the ESWT-group compared with the control group.

CONCLUSION

ESWT-treated ulcers had a significant reduction in wound size and median time required for ulcer healing, with no adverse reactions. So, the ESWT is advocated as an adjunctive therapy in chronic diabetic wound.

Alloxan diabetes alters the tensile strength, morphological and morphometric parameters of abdominal wall healing in rats

PURPOSE

To investigate the effects of alloxan diabetes on the abdominal wall healing of rats undergoing laparotomy.

METHODS

Ninety-six male Wistar rats weighing between 200 and 300 grams, divided into two groups: non-diabetic group (G1) and another with untreated diabetes (G2). Three months after diabetes induction, the animals underwent a 5cm-long- laparotomy and 5.0 nylon monofilament suture. After the surgery, 12 animals from each group were euthanized on days 4, 14, 21 and 30 corresponding to the moments M1, M2, M3 and M4. In each moment a fragment of the abdominal wall containing the scar was removed for tensile strength measurement, histological and morphometric study. Clinical and biochemical parameters were also analyzed.

RESULTS

G2 animals showed parameters compatible with severe diabetes and decreased plasma levels of insulin. The tensile strength in G2 was significantly smaller in M2 and M4, with a tendency to fall in the other two. Through light microscope, diabetic animals showed more difficulty to increase collagen density and contraction. G2 animals showed high cellularity of fibroblasts in later healing moments, with collagen thinning in M2 and M4.

CONCLUSION

The abdominal wound healing in untreated diabetic animals was altered and led to a higher incidence of dehiscence and infections.

Shock wave treatment enhances cell proliferation and improves wound healing by ATP release-coupled extracellular signal-regulated kinase (ERK) activation

Shock wave treatment accelerates impaired wound healing in diverse clinical situations. However, the mechanisms underlying the beneficial effects of shock waves have not yet been fully revealed. Because cell proliferation is a major requirement in the wound healing cascade, we used in vitro studies and an in vivo wound healing model to study whether shock wave treatment influences proliferation by altering major extracellular factors and signaling pathways involved in cell proliferation. We identified extracellular ATP, released in an energy- and pulse number-dependent manner, as a trigger of the biological effects of shock wave treatment. Shock wave treatment induced ATP release, increased Erk1/2 and p38 MAPK activation, and enhanced proliferation in three different cell types (C3H10T1/2 murine mesenchymal progenitor cells, primary human adipose tissue-derived stem cells, and a human Jurkat T cell line) in vitro. Purinergic signaling-induced Erk1/2 activation was found to be essential for this proliferative effect, which was further confirmed by in vivo studies in a rat wound healing model where shock wave treatment induced proliferation and increased wound healing in an Erk1/2-dependent fashion. In summary, this report demonstrates that shock wave treatment triggers release of cellular ATP, which subsequently activates purinergic receptors and finally enhances proliferation in vitro and in vivo via downstream Erk1/2 signaling. In conclusion, our findings shed further light on the molecular mechanisms by which shock wave treatment exerts its beneficial effects. These findings could help to improve the clinical use of shock wave treatment for wound healing.

Effects of the diabetic condition on grafted fat survival: an experimental study using streptozotocin-induced diabetic rats

Background

Autologous fat grafts have been widely used for cosmetic purposes and for soft tissue contour reconstruction. Because diabetes mellitus is one of the major chronic diseases in nearly every country, the requirement for fat grafts in diabetes patients is expected to increase continuously. However, the circulation complications of diabetes are serious and have been shown to involve microvascular problems, impairing ischemia-driven neovascularization in particular. After injection, revascularization is vital to the survival of the grafted fat. In this study, the authors attempted to determine whether the diabetic condition inhibits the survival of injected fat due to impaired neovascularization.

Methods

The rat scalp was used for testing fat graft survival. Forty-four seven-week-old male Sprague-Dawley rats were allocated to a diabetic group or a control group. 1.0 mL of processed fat was injected subcutaneously into the scalp of each rat. The effect of diabetes was evaluated by calculating the volume and the weight of the grafted fat and by histologically analyzing the fat sections.

Results

The surviving fat graft volume and weight were considerably smaller in the diabetic group than in the control group (P<0.05), and histological evaluations showed less vascularity, and more cysts, vacuoles, and fibrosis in the diabetic group (P<0.05). Cellular integrity and inflammation were not considerably different in the two groups.

Conclusions

As the final outcome, we found that the presence of diabetes might impair the survival and the quality of fat grafts, as evidenced by lower fat graft weights and volumes and poor histologic graft quality.

Continuous electrical current and zinc sulphate administered by transdermal iontophoresis improves skin healing in diabetic rats induced by alloxan: morphological and ultrastructural analysis

PURPOSE

Evaluated the effects of continuous electrical current (CEC) or zinc administrated by transdermal iontophoresis (Zn+TDI).

METHODS

120 male Wistar rats were submitted to an incision surgery at the anterior region of abdomen and distributed into 6 experimental groups with 40 animals: 3 diabetic groups and 3 normal groups, untreated and treated with CEC alone or with Zn + TDI. Each group was further divided into 4 subgroups with 10 rats each to be evaluated on the 4th, 7th, 14th, and 21st day after surgery. In each period, clinical and laboratory parameters from the animals were analyzed.

RESULTS

The analysis by optical and scanning electron microscopy showed a delay in the phases of wound healing in diabetic rats without treatment in all periods of the experiment; breaking strength (BS) was significantly reduced in skin scars of untreated diabetic rats when compared to other groups. In contrast, BS in skin scars of nondiabetic groups and diabetic rats treated with Zn + TDI showed significant increase in those, besides not presenting delayed healing.

CONCLUSION

Electrical stimulation of surgical wounds used alone or in association with zinc by TDI is able to consistently improve the morphological and ultrastructural changes observed in the healing of diabetic animals.

The dose-effect relationship in extracorporeal shock wave therapy: the optimal parameter for extracorporeal shock wave therapy

BACKGROUND

Extracorporeal shock wave therapy (ESWT) has been demonstrated to have the angiogenic effect on ischemic tissue. We hypothesize that ESWT exerts the proangiogenesis effect with an energy density-dependent mode on the target cells.

MATERIALS AND METHODS

Endothelial progenitor cells (EPCs) of rats were obtained by cultivation of bone marrow-derived mononuclear cells. EPCs were divided into five groups of different energy densities, and each group was furthermore subdivided into four groups of different shock numbers. Thus, there were 20 subgroups in total. The expressions of angiogenic factors, apoptotic factors, inflammation mediators, and chemotactic factors were examined, and the proliferation activity was measured after ESWT.

RESULTS

When EPCs were treated with low-energy (0.04-0.13 mJ/mm(2)) shock wave, the expressions of endothelial nitric oxide synthase, angiopoietin (Ang) 1, Ang-2, and B-cell lymphoma 2 increased and those of interleukin 6, fibroblast growth factor 2, C-X-C chemokine receptor type 4, vascular endothelial growth factor a, Bcl-2-associated X protein, and caspase 3 decreased. stromal cell-derived factor 1 changed without statistical significance. When cells were treated with high-energy (0.16 mJ/mm(2)) shock wave, most of the expressions of cytokines declined except the apoptotic factors and fibroblast growth factor 2, and cells lead to apoptosis. The proliferation activity and the ratio of Ang-1/Ang-2 reached their peak values, when cells were treated with ESWT with the intensity ranging from 0.10-0.13 mJ/mm(2) and shock number ranging from 200-300 impulses. Meanwhile, a minimal value of the ratio of Bax/Bcl-2 was observed.

CONCLUSIONS

There is a dose-effect relationship in ESWT. The shock intensity ranging from 0.10-0.13 mJ/mm(2) and shock number ranging from 200-300 impulses were the optimal parameters for ESWT to treat cells in vitro.