Therapeutic ultrasound stimulation of tendon cell migration

Efficacy of shock wave therapy and ultrasound therapy in non-insertional Achilles tendinopathy: a randomised clinical trial

Objective

Physiotherapists and physicians continue to seek effective conservative treatments for Achilles tendinopathy. This study aimed to subjectively and objectively determine the therapeutic efficacy of radial shock wave therapy (RSWT) and ultrasound therapy in non-insertional Achilles tendinopathy.

Materials and methods

Thirty-nine patients with non-insertional Achilles tendinopathy were randomly assigned to three experimental groups, i.e., RSWT (group A), ultrasound therapy (group B), and placebo ultrasound (group C) groups. Before the intervention and at weeks 1 and 6 after the treatment, the patients were assessed using the Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire and posturographic measurements of step initiation performed on the force platforms under two different conditions (non-perturbed transit and perturbed transit).

Results

Six weeks after therapy, all groups exhibited significantly increased VISA-A scores against the measurement at week 1 after therapy. The post-therapy percentage changes in VISA-A scores were significantly greater in group A compared to group B. The three-way ANOVA demonstrated that treatment type affected sway range in the frontal plane and mean velocity of the centre of foot pressure displacements in the sagittal and frontal planes during quiet standing before step initiation. The Bonferroni post-hoc test showed that the means of all those variables were significantly smaller for group A than for group B patients. The three-way ANOVA revealed an effect of the platform arrangement on transit time and double-support period. The Bonferroni post-hoc test revealed statistically longer transit time for the perturbed vs. non-perturbed trials; a reverse relationship was observed for the double-support period.

Conclusion

The VISA-A showed that RSWT was significantly more effective than sonotherapy for alleviation of pain intensity as well as function and activity improvement in patients with non-insertional Achilles tendinopathy. Therefore, RSWT therapy can be used in clinical practice by physiotherapists to alleviate the symptoms of non-insertional Achilles tendinopathy. Objective data registered by force platforms during quiet standing before and after step initiation did not prove useful for monitoring the progress of treatment applied to patients with non-insertional Achilles tendinopathy between consecutive therapy interventions.Clinical trial registration:https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12617000860369, identifier (ACTRN12617000860369).

Effects of Low-Intensity Pulsed Ultrasound in Tendon Injuries

Tendon injuries are the most common soft tissue injuries, caused by tissue overuse and age-related degeneration. However, the tendon repair process is slow and inefficient due to the lack of cellular structure and blood vessels in the tendon. Low-intensity pulsed ultrasound (LIPUS) has received increasing attention as a non-invasive, simple, and safe way to promote tendon healing. This review summarizes the effects and underlying mechanisms of LIPUS on tendon injury by comprehensively examining the published literature, including in vitro, in vivo, and clinical studies. This review reviewed 24 studies, with 87.5% showing improvement. The application of LIPUS in tendon diseases is a promising field worthy of further study.

A preliminary investigation into the impact of shock wave therapy and sonotherapy on postural control of stepping tasks in patients with Achilles tendinopathy

Objective

The outcomes of physical therapy are commonly assessed with subjective scales and questionnaires. Hence, a continuous search to identify diagnostic tests that would facilitate objective assessment of symptom reduction in those patients with Achilles tendinopathy who undergo mechanotherapy. The main aim of this study was to evaluate and compare the effectiveness of shock wave and ultrasound treatments, using objective posturographic assessment during step-up and step-down initiation.

Materials and methods

The patients with non-insertional Achilles tendinopathy and pain lasting for more than 3 months were randomly assigned to one of the experimental groups, i.e., radial shock wave therapy (RSWT), ultrasound therapy, or placebo ultrasound. All groups also received deep friction massage as the primary therapy. The transitional locomotor task was performed with the affected and unaffected limb in random order, on two force platforms under two conditions (step-up and step-down). The recording of center of foot pressure displacements was divided into three phases: quiet standing before step-up/step-down, transit, and quiet standing until measurement completion. Pre-intervention measurements were performed and then short-term follow-ups at weeks 1 and 6 post-therapy.

Results

The three-way repeated measures ANOVA showed few statistically significant two-factor interactions between therapy type, time point of measurement and the type of the locomotor task. Significant increases in postural sway were observed in the entire study population throughout the follow-up period. Three-way ANOVAs revealed a group effect (shock wave vs. ultrasound) on almost all variables of the quiet standing phase prior to step-up/step-down initiation. Overall, postural stability before the step-up and step-down tasks appeared to be more efficient in patients who had undergone RSWT compared to the ultrasound group.

Conclusion

Objective posturographic assessment during step-up and step-down initiation did not demonstrate therapeutic superiority of any of the three therapeutic interventions used in patients with non-insertional Achilles tendinopathy.Clinical Trial Registration: The trial was prospectively registered in the Australian and New Zealand Clinical Trials Registry (no. ACTRN12617000860369; registration date: 9.06.2017).

Exosomes and ultrasound: The future of theranostic applications

Biomaterials and pertaining formulations have been very successful in various diagnostic and therapeutic applications because of its ability to overcome pharmacological limitations. Some of them have gained significant focus in the recent decade for their theranostic properties. Exosomes can be grouped as biomaterials, since they consist of various biological micro/macromolecules and possess all the properties of a stable biomaterial with size in nano range. Significant research has gone into isolation and exploitation of exosomes as potential theranostic agent. However, the limitations in terms of yield, efficacy, and target specificity are continuously being addressed. On the other hand, several nano/microformulations are responsive to physical or chemical alterations and were successfully stimulated by tweaking the physical characteristics of the surrounding environment they are in. Some of them are termed as photodynamic, sonodynamic or thermodynamic therapeutic systems. In this regard, ultrasound and acoustic systems were extensively studied for its ability towards altering the properties of the systems to which they were applied on. In this review, we have detailed about the diagnostic and therapeutic applications of exosomes and ultrasound separately, consisting of their conventional applications, drawbacks, and developments for addressing the challenges. The information were categorized into various sections that provide complete overview of the isolation strategies and theranostic applications of exosomes in various diseases. Then the ultrasound-based disease diagnosis and therapy were elaborated, with special interest towards the use of ultrasound in enhancing the efficacy of nanomedicines and nanodrug delivery systems, Finally, we discussed about the ability of ultrasound in enhancing the diagnostic and therapeutic properties of exosomes, which could be the future of theranostics.

Effect of Therapeutic Ultrasound on the Mechanical and Biological Properties of Fibroblasts

Purpose

This paper explores the effect of therapeutic ultrasound on the mechanical and biological properties of ligament fibroblasts.

Methods and Results

We assessed pulsed ultrasound doses of 1.0 and 2.0 W/cm2 at 1 MHz frequency for five days on ligament fibroblasts using a multidisciplinary approach. Atomic force microscopy showed a decrease in cell elastic modulus for both doses, but the treated cells were still viable based on flow cytometry. Finite element method analysis exhibited visible cytoskeleton displacements and decreased harmonics in treated cells. Colorimetric assay revealed increased cell proliferation, while scratch assay showed increased migration at a low dose. Enzyme-linked immunoassay detected increased collagen and fibronectin at a high dose, and immunofluorescence imaging technique visualized β-actin expression for both treatments.

Conclusion

Both doses of ultrasound altered the fibroblast mechanical properties due to cytoskeletal reorganization and enhanced the regenerative and remodeling stages of cell repair.

Lay Summary

Knee ligament injuries are a lesion of the musculoskeletal system frequently diagnosed in active and sedentary lifestyles in young and older populations. Therapeutic ultrasound is a rehabilitation strategy that may lead to the regenerative and remodeling of ligament wound healing. This research demonstrated that pulsed therapeutic ultrasound applied for 5 days reorganized the ligament fibroblasts structure to increase the cell proliferation and migration at a low dose and to increase the releasing proteins that give the stiffness of the healed ligament at a high dose.

Future Works

Future research should further develop and confirm that therapeutic ultrasound may improve the regenerative and remodeling stages of the ligament healing process applied in clinical trials in active and sedentary lifestyles in young and older populations.

Graphical abstract

Inhibition of Smad3 promotes the healing of rotator cuff injury in a rat model

To investigate the effect of inhibiting transforming growth factor-β (TGF-β1)/Smad2/3 signaling on rotator cuff (RC) healing. A bilateral supraspinatus tendon detachment-repair model of Sprague-Dawley (SD) rats was utilized. A total of 120 SD rats were randomly assigned to six groups and each group received the subacromial injection of normal saline, empty vectors, or lentiviral vectors containing small interfering RNA against TGF-β1, Smad2, Smad3 at the bone-tendon junction. Biomechanical and histological analyses were performed to evaluate bone-tendon junction healing quality at 8 weeks after repair. Histologically, scar healing was found in all surgical groups. Animals with inhibited Smad3 exhibited better bone-tendon junction structures with higher density, parallel orientation, and collagen fiber continuity than other surgical group animals. Immunohistochemistry revealed that the protein expression level of collagen I in animals with inhibited Smad3 was more prominent compared with all other surgical groups. Biomechanically, Animals with inhibited Smad3 showed better results in the maximum load at 4, 6, and 8 weeks after surgery compared with other surgical groups. Besides, C3H10T1/2 (Smad3-) cells increased TT-D6 cell migration and tendon-associated genes expression (scleraxis, tenascin C, collagen I) in coculture system. We conclude that inhibition of Smad3 promotes RC tendon healing in the rat supraspinatus model.

Low Intensity Ultrasound Induces Epithelial Cell Adhesion Responses

In this study, we investigated the cellular mechanosensitive responses to a low intensity ultrasound (LIUS) stimulation (ISATA = 1 mW/cm2, pressure = 10 kPa). The dose and temporal effects at cell-substrate adhesion (CSA) at the basal level and cell-cell adhesion (CCA) at the apical level are reported in detail. A model of mouse mammary gland epithelial cells (EpH4) and the phosphorylation of mechanosensitive 130 kDa Crk-associated substrate (p130CAS) as an indicator for cellular responses were used. The intensity of phospho-p130CAS was found to be dependent on LIUS stress level, and the p130CAS was phosphorylated after 1 min stimulation at CSA. The phospho-p130CAS was also found to increase significantly at CCA upon LIUS stimulation. We confirmed that the cellular responses to ultrasound are immediate and dose dependent. Ultrasound affects not only CSA but also CCA. An E-cadherin knockout (EpH4ECad-/-) model also confirmed that phosphorylation of p130CAS at CCA is related to E-cadherins.

Chaperonin containing T-complex polypeptide subunit eta is a potential marker of joint contracture: an experimental study in the rat

Joint contracture is a fibroproliferative disorder that restricts joint mobility, resulting in tissue degeneration and deformity. However, the etiology of joint contracture is still unknown. Chaperonin containing T-complex polypeptide subunit eta (CCT-eta) is reported to increase in fibrotic diseases. The purpose of this study was to investigate whether CCT-eta is implicated in joint contracture and to determine the role of CCT-eta in the progression of joint contracture by analyzing a rat model. We immobilized the left knee joint of rat by internal fixation for 8 weeks. The non-immobilized right leg served as a control. The range of motion (ROM) of the knee was investigated. Fibroblasts were obtained from the posterior joint capsule of the joints. The outcome was followed by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, fibroblast migration assay, and collagen assay. The effect of CCT-eta on the functions of fibroblasts was observed by utilizing a short inhibitory RNA (siRNA) targeting CCT-eta. The ROM of the immobilized joints was significantly limited compared to the contralateral joints (p < 0.05). Fibroblasts derived from the contractive joints showed higher mRNA and protein expressions of CCT-eta in parallel with alpha-smooth muscle actin (α-SMA) compared to the cells from the contralateral knees (p < 0.05). siRNA-mediated downregulation of CCT-eta inhibited the expressions of both CCT-eta and α-SMA. Moreover, the reduction of CCT-eta also significantly decreased fibroblast functions such as cell mobility and collagen synthesis (all p < 0.05). Our findings indicate that CCT-eta appears to be a potential marker of joint contracture disease.

Low intensity ultrasound stimulates osteoblast migration at different frequencies

This study investigated the effects of different frequencies of low intensity ultrasound on osteoblast migration using an in vitro scratch-wound healing assay. Mouse calvarial-derived MC3T3-E1 osteoblasts in culture were exposed to continuous 45 kHz ultrasound (25 mW/cm(2)) or pulsed 1 MHz ultrasound (250 mW/cm(2)) for 30 min followed by 2 days' culture. Ultrasound treatment with either kHz or MHz output similarly and significantly increased cell numbers after 2 days in culture compared with untreated control cultures. In the scratch-wound healing assay the presence of the cell proliferation inhibitor mitomycin C (MMC) did not influence scratch-wound closure in control cultures indicating that cell migration was responsible for the in vitro wound healing. Application of ultrasound significantly stimulated wound closure. MMC did not affect kHz-stimulated in vitro wound healing; however, MMC reduced in part the scratch-wound closure rate in MHz-treated cultures suggesting that enhanced cell proliferation as well as migration was involved in the healing promoted by MHz ultrasound. In conclusion, both continuous kHz and pulsed MHz ultrasound promoted osteoblastic migration; however, subtle differences were apparent in the manner the different ultrasound regimens enhanced in vitro scratch-wound healing.

Low-level laser irradiation stimulates tenocyte migration with up-regulation of dynamin II expression

Low-level laser therapy (LLLT) is commonly used to treat sports-related tendinopathy or tendon injury. Tendon healing requires tenocyte migration to the repair site, followed by proliferation and synthesis of the extracellular matrix. This study was designed to determine the effect of laser on tenocyte migration. Furthermore, the correlation between this effect and expression of dynamin 2, a positive regulator of cell motility, was also investigated. Tenocytes intrinsic to rat Achilles tendon were treated with low-level laser (660 nm with energy density at 1.0, 1.5, and 2.0 J/cm²). Tenocyte migration was evaluated by an in vitro wound healing model and by transwell filter migration assay. The messenger RNA (mRNA) and protein expressions of dynamin 2 were determined by reverse transcription/real-time polymerase chain reaction (real-time PCR) and Western blot analysis respectively. Immunofluorescence staining was used to evaluate the dynamin 2 expression in tenocytes. Tenocytes with or without laser irradiation was treated with dynasore, a dynamin competitor and then underwent transwell filter migration assay. In vitro wound model revealed that more tenocytes with laser irradiation migrated across the wound border to the cell-free zone. Transwell filter migration assay confirmed that tenocyte migration was enhanced dose-dependently by laser. Real-time PCR and Western-blot analysis demonstrated that mRNA and protein expressions of dynamin 2 were up-regulated by laser irradiation dose-dependently. Confocal microscopy showed that laser enhanced the expression of dynamin 2 in cytoplasm of tenocytes. The stimulation effect of laser on tenocytes migration was suppressed by dynasore. In conclusion, low-level laser irradiation stimulates tenocyte migration in a process that is mediated by up-regulation of dynamin 2, which can be suppressed by dynasore.

[Effects of two methods of heat therapy on the acute vascular response and hemodynamics in healthy subjects]

OBJECTIVE

Recently, non-pharmacological resources to relieve pain like hot packs and ultrasound (US) have become common in clinical practice. However, little experimental evidence is available about the possible mechanisms through which these methods bring about pain relief. We aimed to determine the effects of hot packs and US on the acute vascular response and on hemodynamic parameters in healthy subjects.

MATERIALS AND METHODS

We conducted an experimental study in 20 healthy subjects (10 men and 10 women; mean age, 22.54±1.70 years). The two interventions were randomly applied: a) hot packs (n=10): 15min at 60°C and b) US (n=10): 15min at 1Mhz. Before and after each intervention, the following vascular parameters were measured in the brachial artery using Doppler ultrasonography with a 7MHz probe: arterial compliance, elastic modulus, beta stiffness index, systolic and diastolic arterial diameters, systolic flow velocity and diastolic flow velocity, systolic/diastolic ratio, resistance index, and pulsatility index. The following hemodynamic parameters were monitored: heart rate and blood pressure (systolic, diastolic, and mean).

RESULTS

After the application of hot packs, we observed changes in diastolic flow velocity and in the pulsatility index (P<05). After the application of US, we observed changes in diastolic flow velocity, systolic/diastolic ratio, resistance index, and arterial compliance (P<05). No changes in hemodynamic parameters were observed after either intervention.

CONCLUSIONS

Applying hot packs or US modifies the physiology of the vascular system but does not affect hemodynamic parameters in healthy subjects.

Chaperonin containing T-complex polypeptide subunit eta (CCT-eta) is a specific regulator of fibroblast motility and contractility

Integumentary wounds in mammalian fetuses heal without scar; this scarless wound healing is intrinsic to fetal tissues and is notable for absence of the contraction seen in postnatal (adult) wounds. The precise molecular signals determining the scarless phenotype remain unclear. We have previously reported that the eta subunit of the chaperonin containing T-complex polypeptide (CCT-eta) is specifically reduced in healing fetal wounds in a rabbit model. In this study, we examine the role of CCT-eta in fibroblast motility and contractility, properties essential to wound healing and scar formation. We demonstrate that CCT-eta (but not CCT-beta) is underexpressed in fetal fibroblasts compared to adult fibroblasts. An in vitro wound healing assay demonstrated that adult fibroblasts showed increased cell migration in response to epidermal growth factor (EGF) and platelet derived growth factor (PDGF) stimulation, whereas fetal fibroblasts were unresponsive. Downregulation of CCT-eta in adult fibroblasts with short inhibitory RNA (siRNA) reduced cellular motility, both basal and growth factor-induced; in contrast, siRNA against CCT-beta had no such effect. Adult fibroblasts were more inherently contractile than fetal fibroblasts by cellular traction force microscopy; this contractility was increased by treatment with EGF and PDGF. CCT-eta siRNA inhibited the PDGF-induction of adult fibroblast contractility, whereas CCT-beta siRNA had no such effect. In each of these instances, the effect of downregulating CCT-eta was to modulate the behavior of adult fibroblasts so as to more closely approximate the characteristics of fetal fibroblasts. We next examined the effect of CCT-eta modulation on alpha-smooth muscle actin (alpha-SMA) expression, a gene product well known to play a critical role in adult wound healing. Fetal fibroblasts were found to constitutively express less alpha-SMA than adult cells. Reduction of CCT-eta with siRNA had minimal effect on cellular beta-actin but markedly decreased alpha-SMA; in contrast, reduction of CCT-beta had minimal effect on either actin isoform. Direct inhibition of alpha-SMA with siRNA reduced both basal and growth factor-induced fibroblast motility. These results indicate that CCT-eta is a specific regulator of fibroblast motility and contractility and may be a key determinant of the scarless wound healing phenotype by means of its specific regulation of alpha-SMA expression.