Superoxide mediates shock wave induction of ERK-dependent osteogenic transcription factor (CBFA1) and mesenchymal cell differentiation toward osteoprogenitors

The application of extracorporeal shock wave therapy on stem cells therapy to treat various diseases

In the last ten years, stem cell (SC) therapy has been extensively used to treat a range of conditions such as degenerative illnesses, ischemia-related organ dysfunction, diabetes, and neurological disorders. However, the clinical application of these therapies is limited due to the poor survival and differentiation potential of stem cells (SCs). Extracorporeal shock wave therapy (ESWT), as a non-invasive therapy, has shown great application potential in enhancing the proliferation, differentiation, migration, and recruitment of stem cells, offering new possibilities for utilizing ESWT in conjunction with stem cells for the treatment of different systemic conditions. The review provides a detailed overview of the advances in using ESWT with SCs to treat musculoskeletal, cardiovascular, genitourinary, and nervous system conditions, suggesting that ESWT is a promising strategy for enhancing the efficacy of SC therapy for various diseases.

Effectiveness of extracorporeal shock wave therapy on functional ability in grade IV knee osteoarthritis - a randomized controlled trial

Extracorporeal shockwave therapy (ESWT) is a non-invasive physical therapy intervention that has emerged in the recent past to address the upswing of osteoarthritis (OA). However, insufficient evidence is present to prove the efficacy of ESWT on grade IV knee osteoarthritis (KOA). The present study aimed to examine the effects of ESWT on functional ability in patients suffering from grade IV KOA. Thirty volunteers aged 45-60 years with grade IV primary KOA diagnosed by an orthopaedic surgeon based on the Kellgren-Lawrence score participated in the study. The participants were equally and randomly divided into two groups (i.e. experimental and control), with 15 participants in each group. The participants in the control group performed conventional physiotherapy (CPT) that included ultrasound therapy, isometric quadriceps, SLR and isometric hip adductor strengthening exercises. The participants in the experimental group received ESWT in addition to CPT. Lower extremity functional scale (LEFS) score was measured before and after the four weeks of intervention. In both groups, a statistically significant (p = 0.001) improvement in LEFS was observed. In the experimental groups, it improved by 81.92% and in the control groups by 48.15%. A statistically significant (p < 0.001) difference was observed in LEFS post-intervention values between both groups. As demonstrated by our trial results, the addition of ESWT to the CPT program will yield beneficial results in ameliorating the functional disability in patients with primary KOA (grade IV). Further studies are needed to confirm and apply these findings to a larger cohort.

The effects and underlying mechanism of extracorporeal shockwave therapy on fracture healing

The clinical efficacy of ESWT in treating bone non union has been widely recognized, but the biological mechanism of ESWT promoting bone non union healing is still unclear. ESWT can make old callus micro fracture through mechanical conduction, form subperiosteal hematoma, promote the release of bioactive factors, reactivate the fracture healing mechanism, rebalance the activities of osteoblasts and osteoclast, promote the angiogenesis of fracture site, and accelerate the healing of bone nonunion.Over recent years, great efforts have been made by both scientists and clinicians to explore the underlying mechanism behind the healing effect of ESWT on bone fractures. In this review, we introduced the growth factors during osteogenesis induced by ESWT hoping to provide new insights in the clinical use of ESWT.

Molecular Mechanisms Underlying the Pain-Relieving Effects of Extracorporeal Shock Wave Therapy: A Focus on Fascia Nociceptors

In recent years, extracorporeal shock wave therapy (ESWT) has received increasing attention for its potential beneficial effects on various bone and soft-tissue pathologies, yielding promising outcomes for pain relief and functional recovery. In fact, ESWT has emerged as an alternative, non-invasive, and safe treatment for the management of numerous musculoskeletal disorders, including myofascial pain syndrome (MPS). In particular, MPS is a common chronic painful condition, accounting for the largest proportion of patients affected by musculoskeletal problems. Remarkably, sensory innervation and nociceptors of the fascial system are emerging to play a pivotal role as pain generators in MPS. At the same time, increasing evidence demonstrates that application of ESWT results in selective loss of sensory unmyelinated nerve fibers, thereby inducing long-lasting analgesia. The findings discussed in the present review are supposed to add novel viewpoints that may further enrich our knowledge on the complex interactions occurring between disorders of the deep fascia including changes in innervation, sensitization of fascial nociceptors, the pathophysiology of chronic musculoskeletal pain of MPS, and EWST-induced analgesia. Moreover, gaining mechanistic insights into the molecular mechanisms of pain-alleviating effects of ESWT may broaden the fields of shock waves clinical practice far beyond the musculoskeletal system or its original application for lithotripsy.

Shockwave Treatment Enhanced Extracellular Matrix Production in Articular Chondrocytes Through Activation of the ROS/MAPK/Nrf2 Signaling Pathway

OBJECTIVE

Shockwave application is a potential treatment for osteoarthritis (OA), but the underlying mechanism remains unknown. Oxidative stress and a counterbalancing antioxidant system might be the key to understanding this mechanism. We hypothesized that reactive oxygen species (ROS) and the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2),which is an important regulator of cellular redox homeostasis, are plausible elements.

DESIGN

Porcine chondrocytes were cultured in a 3-dimensional pellet model and subjected to shockwaves. The effects of shockwaves with various energy-flux densities on optimal extracellular matrix (ECM) synthesis were assessed. ROS, mitogen-activated protein kinase (MAPK) signaling, and the redox activity of Nrf2 were measured. To investigate the signaling mechanism involved in the shockwave treatment in chondrocytes, specific inhibitors of ROS, MAPK signaling, and Nrf2 activity were targeted.

RESULTS

Shockwaves increased ECM synthesis without affecting cell viability or proliferation. Furthermore, they induced transient ROS production mainly through xanthine oxidase. The phosphorylation of ERK1/2 and p38 and the nuclear translocation of Nrf2 were activated by shockwaves. By contrast, suppression of ROS signaling mitigated shockwave-induced MAPK phosphorylation, Nrf2 nuclear translocation, and ECM synthesis. Pretreatment of chondrocytes with the specific inhibitors of MEK1/2 and p38, respectively, mitigated the shockwave-induced nuclear translocation of Nrf2 and ECM synthesis. Nrf2 inhibition by both small hairpin RNA knockdown and brusatol reduced the shockwave-enhanced ECM synthesis.

CONCLUSIONS

Shockwaves activated Nrf2 activity through the induction of transient ROS signaling and subsequently enhanced ECM synthesis in chondrocytes. This study provided fundamental evidence confirming the potential of shockwaves for OA management.

Mechanical Stimulation of Fibroblasts by Extracorporeal Shock Waves: Modulation of Cell Activation and Proliferation Through a Transient Proinflammatory Milieu

Extracorporeal shock waves (ESWTs) are “mechanical” waves, widely used in regenerative medicine, including soft tissue wound repair. Although already being used in the clinical practice, the mechanism of action underlying their biological activities is still not fully understood. In the present paper we tried to elucidate whether a proinflammatory effect may contribute to the regenerative potential of shock waves treatment. For this purpose, we exposed human foreskin fibroblasts (HFF1 cells) to an ESWT treatment (100 pulses using energy flux densities of 0.19 mJ/mm² at 3 Hz), followed by cell analyses after 5 min, up to 48 h. We then evaluated cell proliferation, reactive oxygen species generation, ATP release, and cytokine production. Cells cultured in the presence of lipopolysaccharide (LPS), to induce inflammation, were used as a positive control, indicating that LPS-mediated induction of a proinflammatory pattern in HFF1 increased their proliferation. Here, we provide evidence that ESWTs affected fibroblast proliferation through the overexpression of selected cytokines involved in the establishment of a proinflammatory program, superimposable to what was observed in LPS-treated cells. The possibility that inflammatory circuits can be modulated by ESWT mechanotransduction may disclose novel hypothesis on their biological underpinning and expand the fields of their biomedical application.

The role of shockwaves in the enhancement of bone repair - from basic principles to clinical application

Extracorporeal shockwave therapy is a treatment modality, originally introduced into the clinic as lithotripsie, which has also been successfully used in the last two decades in the non-invasive treatment of delayed or non-healing fractures. Initially, the mechanism of action was attributed to microfracture-induced repair, but intensive basic research has now shown that the shockwave generates its effect in tissue via mechanotransduction. Numerous signal transduction pathways have already been demonstrated, which in their entirety trigger an endogenous regeneration process via cell proliferation, migration and differentiation. Clinically, these shockwave-conveyed biological signals support healing of acute, delayed and non-union fractures. The attainable outcome is comparable to surgery but avoiding an open approach with associated potential complications. These advantageous properties with a clearly positive cost-benefit ratio make shockwave therapy a first line treatment in delayed and non-union fractures.

It Comes As a Shock: Kidney Repair Using Shockwave Therapy

Chronic kidney disease is a global health care burden, yet clinically-proven treatments are limited. Low-intensity shockwave, which utilizes ≈10% of the energy levels used in clinically indicated shockwave lithotripsy, is a promising technique to ameliorate ischemia and regenerate tissues. It has been demonstrated to improve healing in tissues such as bone, muscle, myocardium, and kidney via several mechanisms, particularly through promoting neovascularization. Low-intensity shockwave stimulates mechanoreceptors located primarily in endothelial and proximal tubular cells and subsequently upregulates vascular endothelial growth factors. This, in turn, promotes angiogenesis and ameliorates renal hypoxia, inflammation, and fibrosis, and ultimately preserves renal function. Furthermore, low-intensity shockwave can stimulate release of homing factors to attract endothelial progenitor or stem cells into injured kidneys for tissue repair. These effects may be beneficial in several kidney disease models, including renal artery stenosis, diabetic kidney disease, and various chronic kidney diseases, although most studies reported to date have been performed in animal models. Because of its low energy intensity, the procedure is relatively tolerable and safe, yet, more clinical studies are needed to establish its efficacy beyond currently existing strategies. Therefore, low-intensity shockwave therapy emerges as an alternative therapeutic approach that may offer a promising noninvasive intervention for treating renal diseases. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02515461; NCT03602807; and NCT03445247.

In Vivo Modulation of Angiogenesis and Immune Response on a Collagen Matrix via Extracorporeal Shockwaves

The effective management of tissue integration and immunological responses to transplants decisively co-determines the success of soft and hard tissue reconstruction. The aim of this in vivo study was to evaluate the eligibility of extracorporeal shock wave therapy (ESWT) with respect to its ability to modulate angiogenesis and immune response to a collagen matrix (CM) for tissue engineering in the chorioallantoic membrane (CAM) assay, which is performed with fertilized chicken eggs. CM were placed on the CAM on embryonic development day (EDD) 7; at EDD-10, ESWT was conducted at 0.12 mJ/mm² with 500 impulses each. One and four days later, angiogenesis represented by vascularized area, vessel density, and vessel junctions as well as HIF-1α and VEGF gene expression were evaluated. Furthermore, immune response (iNOS2, MMP-9, and MMP-13 via qPCR) was assessed and compared between ESWT- and non-ESWT-groups. At EDD-14, the vascularized area (+115% vs. +26%) and the increase in vessel junctions (+751% vs. +363%) were significantly higher in the ESWT-group. ESWT significantly increased MMP-9 gene expression at EDD-11 and significantly decreased MMP-13 gene expression at EDD-14 as compared to the controls. Using the CAM assay, an enhanced angiogenesis and neovascularization in CM after ESWT were observed. Furthermore, ESWT could reduce the inflammatory activity after a latency of four days.

The effects of shock wave stimulation of mesenchymal stem cells on proliferation, migration, and differentiation in an injectable gelatin matrix for osteogenic regeneration

The treatment of a variety of defects in bony sites could benefit from mitogenic stimulation of osteoprogenitor cells, including endogenous bone marrow-derived mesenchymal stem cells (bMSCs), and from provision of such cells with a matrix permissive of their migration, proliferation, and osteogenic differentiation. That such MSC stimulation could result from treatment with noninvasive (extracorporeal) shock waves (ESWs), and the matrix delivered by injection could enable this therapeutic approach to be employed for applications in which preformed scaffolds and growth factor therapy are difficult to deploy. The objectives of the present study were to investigate focused ESWs for their effects on proliferation, migration, and osteogenic differentiation in an injectable gelatin (Gtn) matrix capable of undergoing covalent cross-linking in vivo. Gtn was conjugated with hydroxyphenyl propionic acid (HPA) in order to enable it to be covalently cross-linked with minute amounts of horseradish peroxidase and hydrogen peroxide. The results demonstrated that 500 shocks of 0.4-mJ/mm² energy flux density resulted in a twofold greater proliferation of bMSCs in the Gtn-HPA matrix after 14 days, compared with bMSCs grown with supplementation with platelet-derived growth factor (PDGF)-BB, a known mitogen for bMSCs. Moreover, SW treatment enhanced substantially osteogenic differentiation of bMSCs. The Gtn-HPA gel was permissive of MSC migration under the chemotactic influence of the growth factor, PDGF-BB, incorporated into and released by the gel. ESW treatment had no effect on the motility of the MSCs. The findings of the study warrant further investigation of this combined treatment modality for select bony defects.

Adult mesenchymal stem cells: is there a role for purine receptors in their osteogenic differentiation?

The role played by mesenchymal stem cells (MSCs) in contributing to adult tissue homeostasis and damage repair thanks to their differentiation capabilities has raised a great interest, mainly in bone regenerative medicine. The growth/function of these undifferentiated cells of mesodermal origin, located in specialized structures (niches) of differentiated organs is influenced by substances present in this microenvironment. Among them, ancestral and ubiquitous molecules such as adenine-based purines, i.e., ATP and adenosine, may be included. Notably, extracellular purine concentrations greatly increase during tissue injury; thus, MSCs are exposed to effects mediated by these agents interacting with their own receptors when they act/migrate in vivo or are transplanted into a damaged tissue. Here, we reported that ATP modulates MSC osteogenic differentiation via different P2Y and P2X receptors, but data are often inconclusive/contradictory so that the ATP receptor importance for MSC physiology/differentiation into osteoblasts is yet undetermined. An exception is represented by P2X7 receptors, whose expression was shown at various differentiation stages of bone cells resulting essential for differentiation/survival of both osteoclasts and osteoblasts. As well, adenosine, usually derived from extracellular ATP metabolism, can promote osteogenesis, likely via A2B receptors, even though findings from human MSCs should be implemented and confirmed in preclinical models. Therefore, although many data have revealed possible effects caused by extracellular purines in bone healing/remodeling, further studies, hopefully performed in in vivo models, are necessary to identify defined roles for these compounds in favoring/increasing the pro-osteogenic properties of MSCs and thereby their usefulness in bone regenerative medicine.

Extracorporeal shock wave therapy mechanisms in musculoskeletal regenerative medicine

Extracorporeal shockwave therapy (ESWT) is a popular non-invasive therapeutic modality in the medical field for the treatment of numerous musculoskeletal disorders. This technique first emerged around the 1980s as extracorporeal shockwave lithotripsy and has been studied since then for its application towards orthopedics and traumatology. ESWT works by the emission of acoustic waves (shockwaves) that carry energy and can propagate through tissues. Shockwaves can generate interstitial and extracellular responses, producing many beneficial effects such as: pain relief, vascularization, protein biosynthesis, cell proliferation, neuro and chondroprotection, and destruction of calcium deposits in musculoskeletal structures. The combination of these effects can lead to tissue regeneration and significant alleviation of pain, improving functional outcomes in injured tissue. Considering these facts, ESWT shows great potential as a useful regenerative medicine technique for the treatment of numerous musculoskeletal injuries.

Role of nanoparticles in osteogenic differentiation of bone marrow mesenchymal stem cells

The present study aimed to investigate the osteoinductive potentiality of some selected nanostructures; Hydroxyapatite (HA-NPs), Gold (Au-NPs), Chitosan (C-NPs), Gold/hydroxyapatite (Au/HA-NPs) and Chitosan/hydroxyapatite (CH-NPs) on bone marrow- derived mesenchymal stem cells (BM-MSCs). These nanostructures were characterized using transmission electron microscope and Zetasizer. MSCs were isolated from bone marrow of rat femur bones and their identity was documented by morphology, flow cytometry and multi-potency capacity. The influence of the selected nanostructures on the viability, osteogenic differentiation and subsequent matrix mineralization of BM-MSCs was determined by MTT assay, molecular genetic analysis and alizarin red S staining, respectively. MTT analysis revealed insignificant toxicity of the tested nanostructures on BM-MSCs at concentrations ranged from 2 to 25 µg/ml over 48 h and 72 h incubation period. Notably, the tested nanostructures potentiate the osteogenic differentiation of BM-MSCs as evidenced by a prominent over-expression of runt-related transcription factor 2 (Runx-2) and bone morphogenetic protein 2 (BMP-2) genes after 7 days incubation. Moreover, the tested nanostructures induced matrix mineralization of BM-MSCs after 21 days as manifested by the formation of calcium nodules stained with alizarin red S. Conclusively, these data provide a compelling evidence for the functionality of the studied nanostructures as osteoinductive materials motivating the differentiation of BM-MSCs into osteoblasts with the most prominent effect observed with Au-NPs and Au/HA-NPs, followed by CH-NPs.

Development of titanium dioxide nanowire incorporated poly(vinylidene fluoride-trifluoroethylene) scaffolds for bone tissue engineering applications

Critical size bone defects that do not heal spontaneously are among the major reasons for the disability in majority of people with locomotor disabilities. Tissue engineering has become a promising approach for repairing such large tissue injuries including critical size bone defects. Three-dimension (3D) porous scaffolds based on piezoelectric polymers like poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) have received a lot of attention in bone tissue engineering due to their favorable osteogenic properties. Owing to the favourable redox properties, titanium dioxide (TiO2) nanostructures have gained a great deal of attention in bone tissue engineering. In this paper, tissue engineering scaffolds based on P(VDF-TrFE) loaded with TiO2 nanowires (TNW) were developed and evaluated for bone tissue engineering. Wet-chemical method was used for the synthesis of TNW. Obtained TNW were thoroughly characterized for the physicochemical and morphological properties using techniques such as X-Ray diffraction (XRD) analysis and transmission electron microscopy (TEM). Electrospinning was used to produce TNW incorporated P(VDF-TrFE) scaffolds. Developed scaffolds were characterized by state of art techniques such as Scanning Electron Microscopy (SEM), XRD and Differential scanning calorimetry (DSC) analyses. TEM analysis revealed that the obtained TiO2 nanostructures possess nanofibrous morphology with an average diameter of 26 ± 4 nm. Results of characterization of nanocomposite scaffolds confirmed the effective loading of TNW in P(VDF-TrFE) matrix. Fabricated P(VDF-TrFE)/TNW scaffolds possessed good mechanical strength and cytocompatibility. Osteoblast like cells showed higher adhesion and proliferation on the nanocomposite scaffolds. This investigation revealed that the developed P(VDF-TrFE) scaffolds containing TNW can be used as potential scaffolds for bone tissue engineering applications.

Treatment of scaphoid waist nonunion by one, two headless compression screws or plate with or without additional extracorporeal shockwave therapy

INTRODUCTION

Scaphoid nonunion remains challenging for hand surgeons. Several treatment options are available such as: non-vascularized or vascularized bone grafting, with or without additional stabilization. In the last few decades, extracorporeal shockwave therapy (ESWT) has become an established procedure for treating delayed and nonunions. Purpose of this retrospective follow-up study was (a) to investigate union rate and clinical outcome of the different implants [either one/two headless compression screws (HCS) or a plate] and (b) union rate and clinical outcome using only surgery, or a combination of surgery and ESWT.

MATERIALS AND METHODS

The study included 42 patients with scaphoid nonunions of the waist with a mean follow-up of 52 months. All patients received a non-vascularized bone graft from the iliac crest and stabilization was achieved by using one, two HCS or a plate. ESWT was performed with 3000 impulses, energy flux density per pulse 0.41 mJ/mm² within 2 weeks after surgery. Clinical assessment included range of motion (ROM), pain according to the Visual Analog Scale (VAS), grip strength, Disability of the Arm Shoulder and Hand Score, Patient-Rated Wrist Evaluation Score, Michigan Hand Outcomes Questionnaire and modified Green O'Brien (Mayo) Wrist Score. In addition, each patient had a CT scan of the wrist.

RESULTS

A total of 33/42 (79%) patients showed union at the follow-up investigation. Patients treated with additional ESWT showed bony healing in 21/26 (81%) and without ESWT in 12/16 (75%). Patients that were stabilized using one HCS showed bony healing in 6/10 (60%), with two HCS 10/12 (83%) and by plate 17/20 (85%). The ESWT group had a significantly lower pain score according to the VAS and better modified Green O'Brien (Mayo) Score. No differences could be found in respect of ROM, grip strength, functional outcome score depending of which stabilization method was used.

CONCLUSIONS

Stabilization of scaphoid waist nonunions with two HCS or plate showed higher union rates than a stabilization using only one HCS. In addition, ESWT combined with a nonvascularized bone graft from the iliac crest seems a suitable option for treating scaphoid nonunions.

Physical Stimulations for Bone and Cartilage Regeneration

A wide range of techniques and methods are actively invented by clinicians and scientists who are dedicated to the field of musculoskeletal tissue regeneration. Biological, chemical, and physiological factors, which play key roles in musculoskeletal tissue development, have been extensively explored. However, physical stimulation is increasingly showing extreme importance in the processes of osteogenic and chondrogenic differentiation, proliferation and maturation through defined dose parameters including mode, frequency, magnitude, and duration of stimuli. Studies have shown manipulation of physical microenvironment is an indispensable strategy for the repair and regeneration of bone and cartilage, and biophysical cues could profoundly promote their regeneration. In this article, we review recent literature on utilization of physical stimulation, such as mechanical forces (cyclic strain, fluid shear stress, etc.), electrical and magnetic fields, ultrasound, shock waves, substrate stimuli, etc., to promote the repair and regeneration of bone and cartilage tissue. Emphasis is placed on the mechanism of cellular response and the potential clinical usage of these stimulations for bone and cartilage regeneration.

Gold and gold-silver alloy nanoparticles enhance the myogenic differentiation of myoblasts through p38 MAPK signaling pathway and promote in vivo skeletal muscle regeneration

Under the severe trauma condition, the skeletal muscles regeneration process is inhibited by forming fibrous scar tissues. Understanding the interaction between bioactive nanomaterials and myoblasts perhaps has important effect on the enhanced skeletal muscle tissue regeneration. Herein, we investigate the effect of monodispersed gold and gold-silver nanoparticles (AuNPs and Au-AgNPs) on the proliferation, myogenic differentiation and associated molecular mechanism of myoblasts (C2C12), as well as the in vivo skeletal muscle tissue regeneration. Our results showed that AuNPs and Au-AgNPs could support myoblast attachment and proliferation with negligible cytotoxicity. Under various incubation conditions (normal and differentiation medium), AuNPs and Au-AuNPs significantly enhanced the myogenic differentiation of myoblasts by upregulating the expressions of myosin heavy chain (MHC) protein and myogenic genes (MyoD, MyoG and Tnnt-1). The further analysis demonstrated that AuNPs and Au-AgNPs could activate the p38α mitogen-activated protein kinase pathway (p38α MAPK) signaling pathway and enhance the myogenic differentiation. Additionally, the AuNPs and Au-AgNPs significantly promote the in vivo skeletal muscle regeneration in a tibialis anterior muscle defect model of rat. This study may provide a nanomaterials-based strategy to improve the skeletal muscle repair and regeneration.

Widespread changes in transcriptome profile of human mesenchymal stem cells induced by two-dimensional nanosilicates

Two-dimensional nanomaterials, an ultrathin class of materials such as graphene, nanoclays, transition metal dichalcogenides (TMDs), and transition metal oxides (TMOs), have emerged as a new generation of materials due to their unique properties relative to macroscale counterparts. However, little is known about the transcriptome dynamics following exposure to these nanomaterials. Here, we investigate the interactions of 2D nanosilicates, a layered clay, with human mesenchymal stem cells (hMSCs) at the whole-transcriptome level by high-throughput sequencing (RNA-seq). Analysis of cell-nanosilicate interactions by monitoring changes in transcriptome profile uncovered key biophysical and biochemical cellular pathways triggered by nanosilicates. A widespread alteration of genes was observed due to nanosilicate exposure as more than 4,000 genes were differentially expressed. The change in mRNA expression levels revealed clathrin-mediated endocytosis of nanosilicates. Nanosilicate attachment to the cell membrane and subsequent cellular internalization activated stress-responsive pathways such as mitogen-activated protein kinase (MAPK), which subsequently directed hMSC differentiation toward osteogenic and chondrogenic lineages. This study provides transcriptomic insight on the role of surface-mediated cellular signaling triggered by nanomaterials and enables development of nanomaterials-based therapeutics for regenerative medicine. This approach in understanding nanomaterial-cell interactions illustrates how change in transcriptomic profile can predict downstream effects following nanomaterial treatment.

A review of the cellular and molecular effects of extracorporeal shockwave therapy

Extracorporeal shockwave therapy (ESWT) is a novel therapeutic modality and its use in promoting connective tissue repair and analgesic effect has been advocated in the literature. It is convenient, cost-effective, and has negligible complications; it therefore bypasses many of the problems associated with surgical interventions. This paper reviews the proposed mechanisms of action in promoting tissue repair and regeneration as well as analysing its efficacy providing an analgesic effect in clinical applications. Further research will be required to not only identify the underlying mechanisms more precisely, but will also be critical for ensuring consistency across the literature so that the most beneficial treatment protocol can be developed. Extracorporeal shockwave therapy stands as a promising alternative modality in promoting tissue repair.

Effect of hydrogel elasticity and ephrinB2-immobilized manner on Runx2 expression of human mesenchymal stem cells

The objective of this study is to design the manner of ephrinB2 immobilized onto polyacrylamide (PAAm) hydrogels with varied elasticity and evaluate the effect of hydrogels elasticity and the immobilized manner of ephrinB2 on the Runx2 expression of human mesenchymal stem cells (hMSC). The PAAm hydrogels were prepared by the radical polymerization of acrylamide (AAm), and N,N'-methylenebisacrylamide (BIS). By changing the BIS concentration, the elasticity of PAAm hydrogels changed from 1 to 70kPa. For the bio-specific immobilization of ephrinB2, a chimeric protein of ephrinB2 and Fc domain was immobilized onto protein A-conjugated PAAm hydrogels by making use of the bio-specific interaction between the Fc domain and protein A. When hMSC were cultured on the ephrinB2-immobilized PAAm hydrogels with varied elasticity, the morphology of hMSC was of cuboidal shape on the PAAm hydrogels immobilized with ephrinB2 compared with non-conjugated ones, irrespective of the hydrogels elasticity. The bio-specific immobilization of ephrinB2 enhanced the level of Runx2 expression. The expression level was significantly high for the hydrogels of 3.6 and 5.9kPa elasticity with bio-specific immobilization of ephrinB2 compared with other hydrogels with the same elasticity. The hydrogels showed a significantly down-regulated RhoA activity. It is concluded that the Runx2 expression of hMSC is synergistically influenced by the hydrogels elasticity and their immobilized manner of ephrinB2 immobilized.

STATEMENT OF SIGNIFICANCE

Differentiation fate of mesenchymal stem cells (MSC) is modified by biochemical and biophysical factors, such as elasticity and signal proteins. However, there are few experiments about combinations of them. In this study, to evaluate the synergistic effect of them on cell properties of MSC, we established to design the manner of Eph signal ligand, ephrinB2, immobilized onto polyacrylamide hydrogels with varied elasticity. The gene expression level of an osteogenic maker, Runx2, was enhanced by the immobilized manner, and significantly enhanced for the hydrogels of around 4kPa elasticity with bio-specific immobilization of ephrinB2. This is the novel report describing to demonstrate that the Runx2 expression of MSC is synergistically influenced by the hydrogels elasticity and their manner of ephrinB2 immobilized.

An Innovative Approach for Enhancing Bone Defect Healing Using PLGA Scaffolds Seeded with Extracorporeal-shock-wave-treated Bone Marrow Mesenchymal Stem Cells (BMSCs)

Although great efforts are being made using growth factors and gene therapy, the repair of bone defects remains a major challenge in modern medicine that has resulted in an increased burden on both healthcare and the economy. Emerging tissue engineering techniques that use of combination of biodegradable poly-lactic-co-glycolic acid (PLGA) and mesenchymal stem cells have shed light on improving bone defect healing; however, additional growth factors are also required with these methods. Therefore, the development of novel and cost-effective approaches is of great importance. Our in vitro results demonstrated that ESW treatment (10 kV, 500 pulses) has a stimulatory effect on the proliferation and osteogenic differentiation of bone marrow-derived MSCs (BMSCs). Histological and micro-CT results showed that PLGA scaffolds seeded with ESW-treated BMSCs produced more bone-like tissue with commitment to the osteogenic lineage when subcutaneously implanted in vivo, as compared to control group. Significantly greater bone formation with a faster mineral apposition rate inside the defect site was observed in the ESW group compared to control group. Biomechanical parameters, including ultimate load and stress at failure, improved over time and were superior to those of the control group. Taken together, this innovative approach shows significant potential in bone tissue regeneration.

A histomorphometric study of necrotic femoral head in rabbits treated with extracorporeal shock waves

[Purpose] This study aimed to determine the effectiveness and mechanisms of extracorporeal shock wave therapy in the treatment of femoral head osteonecrosis. [Subjects and Methods] Histomorphometric analysis of necrotic femoral head in rabbits treated with shock waves was performed. Bilateral osteonecrosis of femoral heads was induced with methylprednisolone and lipopolysaccharide in eight rabbits. The left limb (study side) received shock waves to the femoral head. The right limb (control side) received no shock waves. Biopsies of the femoral heads were performed at 12 weeks after shock wave therapy. [Results] Necrotic femoral heads treated with shock waves, compared with controls, had higher bone volume per tissue volume, trabecular thickness, trabecular number, osteoblast surface/bone surface, osteoid surface/bone surface, osteoid thickness, mineralizing surface/bone surface, mineralizing apposition rate, and bone formation rate. However, trabecular separation was lower in shock wave-treated femoral heads than in controls. Eroded surface/bone surface and osteoclast surface/bone surface did not differ significantly between groups. [Conclusion] The bone mass of necrotic femoral heads treated with shock waves increases. Extracorporeal shock wave may promote bone repair in necrotic femoral heads through the proliferation and activation of osteoblasts.

Extracorporeal Shockwave Therapy Enhances Expression of Pdia-3 Which Is a Key Factor of the 1α,25-Dihydroxyvitamin D 3 Rapid Membrane Signaling Pathway in Treatment of Early Osteoarthritis of the Knee

The goal of our research was demonstrated that multiple molecules in microenvironments of the early osteoarthritis (OA) joint tissue may be actively responded to extracorporeal shockwave therapy (ESWT) treatment, which potentially regulated biological function of chondrocytes and synovial cells in early OA knee. We demonstrated that shockwave treatment induced the expression of protein-disulfide isomerase-associated 3 (Pdia-3) which was a significant mediator of the 1α,25-Dihydroxyvitamin D 3 (1α,25(OH)2D3) rapid signaling pathway, using two-dimensional electrophoresis, histological analysis and quantitative polymerase chain reaction (qPCR). We observed that the expression of Pdia-3 at 2 weeks was significantly higher than that of other group at 4, 8, and 12 weeks post-shockwave treatment in early OA rat knee model. The other factors of the rapid membrane signaling pathway, including extracellular signal-regulated protein kinases 1 (ERK1), osteopontin (OPG), alkaline phosphatase (ALP), and matrix metallopeptidase 13 (MMP13) were examined and were found to be significantly increased at 2 weeks post-shockwave treatment by qPCR in early OA of the knee. Our proteomic data revealed significant Pdia-3 expression in microenvironments of OA joint tissue that could be actively responded to ESWT, which may potentially regulate the biological functions of chondrocytes and osteoblasts in the treatment of the early OA of the knee.

Mesenchymal stem cells as therapeutic target of biophysical stimulation for the treatment of musculoskeletal disorders

BACKGROUND

Musculoskeletal disorders are regarded as a major cause of worldwide morbidity and disability, and they result in huge costs for national health care systems. Traditional therapies frequently turned out to be poorly effective in treating bone, cartilage, and tendon disorders or joint degeneration. As a consequence, the development of novel biological therapies that can treat more effectively these conditions should be the highest priority in regenerative medicine. Mesenchymal stem cells (MSCs) represent one of the most promising tools in musculoskeletal tissue regenerative medicine, thanks to their proliferation and differentiation potential and their immunomodulatory and trophic ability. Indeed, MSC-based approaches have been proposed for the treatment of almost all orthopedic conditions, starting from different cell sources, alone or in combination with scaffolds and growth factors, and in one-step or two-step procedures. While all these approaches would require cell harvesting and transplantation, the possibility to stimulate the endogenous MSCs to enhance their tissue homeostasis activity represents a less-invasive and cost-effective therapeutic strategy. Nowadays, the role of tissue-specific resident stem cells as possible therapeutic target in degenerative pathologies is underinvestigated. Biophysical stimulations, and in particular extracorporeal shock waves treatment and pulsed electromagnetic fields, are able to induce proliferation and support differentiation of MSCs from different origins and affect their paracrine production of growth factors and cytokines.

SHORT CONCLUSIONS

The present review reports the attempts to exploit the resident stem cell potential in musculoskeletal pathologies, highlighting the role of MSCs as therapeutic target of currently applied biophysical treatments.

Extracorporeal shockwave therapy as a novel and potential treatment for degenerative cartilage and bone disease: Osteoarthritis. A qualitative analysis of the literature

Osteoarthritis (OA) is characterized with pathological changes on articular cartilage and subchondral bone, with clinical symptoms of pain and motor dysfunction in affected joints. A growing number of investigations demonstrated the therapeutic effects of extracorporeal shockwave therapy (ESWT) on joints with OA. While the partial mechanisms of action are based on cellular mechanotransduction through cytoskeleton into nuclei to regulate gene expression and cause biophysical influences, the efficacy and exact mechanisms are still under exploration. At present, a summary of the evidence regarding effectiveness of ESWT on OA is not available. The purpose of this review is thus to offer an overview of ESWT in the management of OA in the aspects of cartilage, subchondral bone, pain sensation and motor function, in hopes of eliciting further multi-disciplinary scientific investigations into this promising application as an adjunct to other modalities or surgery. The optimal frequencies, impulses, energy intensity and protocols of ESWT in the management of OA continue to be elucidated. Further studies are required to reveal its exact mechanisms and biophysical effects on cells, animals and humans prior to the clinical application.

Focal Adhesion Kinase Signaling Mediated the Enhancement of Osteogenesis of Human Mesenchymal Stem Cells Induced by Extracorporeal Shockwave

Extracorporeal shockwave (ESW) has been shown of great potential in promoting the osteogenesis of bone marrow mesenchymal stem cells (BMSCs), but it is unknown whether this osteogenic promotion effect can also be achieved in other MSCs (i.e., tendon-derived stem cells (TDSCs) and adipose-derived stem cells (ADSCs)). In the current study, we aimed not only to compare the osteogenic effects of BMSCs induced by ESW to those of TDSCs and ADSCs; but also to investigate the underlying mechanisms. We show here that ESW (0.16 mj/mm(2)) significantly promoted the osteogenic differentiation in all the tested types of MSCs, accompanied with the downregulation of miR-138, but the activation of FAK, ERK1/2, and RUNX2. The enhancement of osteogenesis in these MSCs was consistently abolished when the cells were pretreated with one of the following conditions: overexpression of miR-138, FAK knockdown using specific siRNA, and U0126, implying that all of these elements are indispensable for mediating the effect of ESW. Moreover, our study provides converging genetic and molecular evidence that the miR-138-FAK-ERK1/2-RUNX2 machinery can be generally activated in ESW-preconditioned MSCs, suggesting that ESW may be a promising therapeutic strategy for the enhancement of osteogenesis of MSCs, regardless of their origins.

Osteonecrosis of Femoral Head Treated with Extracorporeal Shock Wave Therapy: Analysis of Short-term Clinical Outcomes of Treatment with Radiologic Staging

Purpose

To evaluate clinical results of extracorporeal shock wave therapy (ESWT) with radiographic staging on patients with avascular necrosis of femoral head (AVNFH).

Materials and Methods

We evaluated 24 patients diagnosed with AVNFH (32 hip joints) who were treated with ESWT from 1993 to 2012. Average follow-up period was 27 months, and the average age of patients was 47.8 years. The Association Research Circulation Osseous (ARCO) system was used to grade radiographic stage prior to treatment. For this study patients were divided into two groups based on their ARCO stage, group 1 (ARCO stages I and II) and group 2 (ARCO stage III). Comparative analyses were done between the two groups using the visual analogue scale (VAS) score and the Harris hip score (HHS) at pre-treatment and 3, 6, 12, and 24 months after treatment. Failure was defined when radiographic stage progressed or arthroplasty surgery was needed due to clinical exacerbation.

Results

Both groups showed clinical improvements with VAS scoring at final follow-up (group 1: median 7 to 1.5, P<0.001; group 2: mean 7 to 4, P=0.056). Using HHS, group 1 showed a significant improvement (from 65.5 to 95 [P<0.001]), while no significance was observed for group 2 (P=0.280). At final follow-up, 3 hips from group 1 and one hip from group 2 showed radiographic improvement; however, two patients underwent total hip arthroplasty due to persistent pain and dysfunction.

Conclusion

ESWT can be considered as an interventional option before surgical treatment in patients with not only early stage AVNFH but also with mid stage.

Effects of BMP-2 and FGF2 on the osteogenesis of bone marrow-derived mesenchymal stem cells in hindlimb-unloaded rats

Hindlimb unloading, as a simulation of microgravity, decreases the osteogenic potential of mesenchymal stem cells (MSCs) from hindlimb femur of rat. We simulated the microgravity by 28-day of hindlimb unloading for male Sprague-Dawley rat, and performed intramuscular injection of BMP-2 and FGF2 at a given interval during hindlimb unloading. Then, the bone marrow (BM) was collected from hindlimb femur of rat. MSCs were isolated from BM, cultured for four passages, and then induced for osteogenesis. The results revealed that the hindlimb unloading decreased the osteogenic potential of MSCs and also the expression of osteoblast gene marker mRNAs in cells induced by osteogenic conditions. Hindlimb unloading for 28 days resulted in the decrease of vinculin-containing focal adhesion in MSCs. During hindlimb unloading, the interval intramuscular injection of BMP-2 or FGF2 alone could increase the osteogenic potential of MSCs and the expression of osteoblast gene marker mRNA. However, the effect of BMP-2 or FGF2 injection alone was significantly lower than that of combination injection of both factors. The further examination showed that the intramuscular injection of BMP-2 promoted the expression of Runx2 mRNA and that the intramuscular injection of FGF2 increased the phosphorylation of ERK and Runx2. Nevertheless, the intramuscular injection of any factor could not increase the formation of vinculin-containing focal adhesions in MSCs. This suggests that BMP-2 should increase the expression of Runx2, and that the activation of Runx2 should be promoted by the FGF2 signaling pathway which activated ERK/Runx2. The activation of this signaling pathway should not lie on the formation of vinculin-containing focal adhesions.

Orchestrating osteogenic differentiation of mesenchymal stem cells--identification of placental growth factor as a mechanosensitive gene with a pro-osteogenic role

Skeletogenesis is initiated during fetal development and persists through adult life as either a remodeling process in response to homeostatic regulation or as a regenerative process in response to physical injury. Mesenchymal stem cells (MSCs) play a crucial role providing progenitor cells from which osteoblasts, bone matrix forming cells are differentiated. The mechanical environment plays an important role in regulating stem cell differentiation into osteoblasts, however, the mechanisms by which MSCs respond to mechanical stimuli are yet to be fully elucidated. To increase understanding of MSC mechanotransuction and osteogenic differentiation, this study aimed to identify novel, mechanically augmented genes and pathways with pro-osteogenic functionality. Using collagen glycoaminoglycan scaffolds as mimics of native extracellular matrix, to create a 3D environment more representative of that found in bone, MSC-seeded constructs were mechanically stimulated in a flow-perfusion bioreactor. Global gene expression profiling techniques were used to identify potential candidates warranting further investigation. Of these, placental growth factor (PGF) was selected and expression levels were shown to strongly correlate to both the magnitude and duration of mechanical stimulation. We demonstrated that PGF gene expression was modulated through an actin polymerization-mediated mechanism. The functional role of PGF in modulating MSC osteogenic differentiation was interrogated, and we showed a concentration-dependent response whereby low concentrations exhibited the strongest pro-osteogenic effect. Furthermore, pre-osteoclast migration and differentiation, as well as endothelial cell tubule formation also maintained concentration-dependent responses to PGF, suggesting a potential role for PGF in bone resorption and angiogenesis, processes key to bone remodeling and fracture repair.

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.

Nitric oxide donors rescue diabetic nephropathy through oxidative-stress-and nitrosative-stress-mediated Wnt signaling pathways

AIMS/INTRODUCTION

The role of the renal nitric oxide (NO) system in the pathophysiology of diabetic nephropathy constitutes a very challenging and fertile field for future investigation. The purpose of the present study was to investigate whether NO donors can attenuate diabetic renal fibrosis and apoptosis through modulating oxidative-and nitrosative-stress, and Wnt signaling using in vivo diabetic models.

MATERIALS AND METHODS

Diabetic rat was induced by a single intraperitoneal injection of streptozotocin. Rats in each group were intraperitoneally given 2,2'-(hydroxynitrosohydrazino)bis-ethanamine (1 U/kg/day) and vehicle for 28 and 56 consecutive days. Expression of the oxidative-and nitrosative-stress, and Wnt signaling components were examined in kidneys from diabetic animals by quantitative reverse transcription polymerase chain reaction, western blot analysis and immunohistochemical staining.

RESULTS

NO donor treatment significantly reduced the ratio of kidney weight to bodyweight and proteinuria. This treatment also significantly restored the suppressive effect of diabetes on urinary NO2 + NO3 levels. Immunohistochemistry showed that NO donor treatment significantly reduced transforming growth factor (TGF)-β1, fibronectin, cleaved caspase-3 and triphosphate-biotin nick end-labeling expression in the glomeruli of diabetic rats. We found that diabetes promoted 8-hydroxy-2'-deoxyguanosine, and peroxynitrite expression coincided with reduced endothelial NO synthase expression in glomeruli. Interestingly, NO donor treatment completely removed oxidative stress and nitrosative stress, and restored endothelial NO synthase expression in diabetic renal glomeruli. Immunohistomorphometry results showed that NO donor treatment significantly restored suppressed Wnt5a expression and β-catenin immunoreactivities in glomeruli. Based on laser-captured microdissection for quantitative reverse transcription polymerase chain reaction, diabetes significantly increased TGF-β1, and fibronectin expression coincided with depressed Wnt5a expression. NO donor treatment reduced TGF-β1, fibronectin activation, and the suppressing effect of diabetes on Wnt5a and β-catenin expression in renal glomeruli.

CONCLUSIONS

NO donor treatment alleviates extracellular matrix accumulation and apoptosis in diabetic nephropathy in vivo by not only preventing the diabetes-mediated oxidative and nitrostative stress, but also restoring downregulation of endothelial NO synthase expression and Wnt/β-catenin signaling. These findings suggest that modulation of NO is a viable alternative strategy for rescuing diabetic renal injury.

Extracorporeal shock wave therapy in periodontics: A new paradigm

The quest for exploring new frontiers in the field of medical science for efficient and improved treatment modalities has always been on a rise. Extracorporeal shock wave therapy (ESWT) has been enormously used in medical practice, principally, for the management of urolithiasis, cholelithiasis and also in various orthopedic and musculoskeletal disorders. The efficacy of ESWT in the stimulation of osteoblasts, fibroblasts, induction of neovascularization and increased expression of bone morphogenic proteins has been well documented in the literature. However, dentistry is no exception to this trend. The present article enlightens the various applications of ESWT in the field of dentistry and explores its prospective applications in the field of periodontics, and the possibility of incorporating the beneficial properties of shock waves in improving the treatment outcome.

Extracorporeal shock wave therapy in musculoskeletal disorders: a review

Regenerative therapy is one of the most challenging and intriguing branches of modern medicine. Basic research has demonstrated the effectiveness of extracorporeal shockwaves (ESWT) in stimulating biological activities that involve intra-cell and cell-matrix interactions. These interactions are at the basis of the current clinical applications, and open the horizons to new applications in tissue regeneration. It is also feasible that shock waves could be used to treat various orthopaedic pathologies, removing the need for surgery. However, suitable translational studies need to be performed before ESWT can become a valid alternative to surgery.

Unfocused extracorporeal shock waves induce anabolic effects in osteoporotic rats

Unfocused extracorporeal shock waves (UESW) have been shown to have an anabolic effect on bone mass. Therefore we investigated the effects of UESW on bone in osteoporotic rats with and without anti-resorptive treatment. Twenty-week-old rats were ovariectomized (n = 27). One group was treated with saline and another group with Alendronate (ALN) 2.4 µg/kg, 3×/week. UESW were applied 2 weeks after ovariectomy. Thousand UESW were applied to one hind leg, the contra-lateral hind leg was not treated and served as control. With the use of in vivo micro-CT scanning it was shown that in saline treated rats trabecular bone volume fraction (BV/TV) was higher at 2 weeks follow-up in UESW treated legs compared to control legs. However, at 4 and 10 weeks no difference was found. In ALN treated animals UESW led to a pronounced anabolic response resulting in an increase in BV/TV at all time-points. Furthermore, UESW resulted in increased cortical volume (CtV), higher trabecular connectivity and, more plate-like and thicker trabeculae. Biomechanical testing showed that UESW lead to a higher maximum force before failure and higher stiffness in all treatment groups. With histology abundant areas of intramembranous bone formation along the periosteal cortex and within the bone marrow were observed. In conclusion this study shows promising results for the use of UESW in the treatment of osteoporosis, especially when this treatment is combined with an anti-resorptive treatment.

Low-intensity pulsed ultrasound enhances BMP-7-induced osteogenic differentiation of human fracture hematoma-derived progenitor cells in vitro

OBJECTIVE

To investigate the effect of the combined application of bone morphogenetic protein-7 (BMP-7) and low-intensity pulsed ultrasound (LIPUS) on human fracture hematoma-derived progenitor cells (HCs).

METHODS

HCs were isolated from 6 patients. The cells were then divided into 4 groups and cultured: (1) control group, HCs cultured in growth medium without LIPUS; (2) LIPUS group, HCs cultured in growth medium with LIPUS; (3) BMP-7 group, HCs cultured in osteogenic medium containing BMP-7 without LIPUS; and (4) BMP-7 + LIPUS group, HCs cultured in osteogenic medium with LIPUS. Osteogenic differentiation potential and proliferation of HCs were compared among 4 groups.

RESULTS

Alkaline phosphatase activity, the expression of osteogenic genes, and the mineralization of HCs in BMP-7 + LIPUS group were shown to be significantly increased compared with the other groups. However, LIPUS did not affect the proliferation of HCs in the presence or absence of BMP-7.

CONCLUSIONS

These findings demonstrated for the first time the significant effect of LIPUS on the osteogenic differentiation of HCs in the presence of BMP-7. This study may provide significant evidence for the clinical combined application of BMP-7 and LIPUS for the treatment of acute bone fractures.

Radial extracorporeal shock wave therapy (rESWT) induces new bone formation in vivo: results of an animal study in rabbits

The aim of this study was to investigate if radial extracorporeal shock wave therapy (rESWT) induces new bone formation and to study the time course of ESWT-induced osteogenesis. A total of 4000 impulses of radial shock waves (0.16 mJ/mm²) were applied to one hind leg of 13 New Zealand white rabbits with the contralateral side used for control. Treatment was repeated after 7 days. Fluorochrome sequence labeling of new bone formation was performed by subcutaneous injection of tetracycline, calcein green, alizarin red and calcein blue. Animals were sacrificed 2 weeks (n = 4), 4 weeks (n = 4) and 6 weeks (n = 5) after the first rESWT and bone sections were analyzed by fluorescence microscopy. Deposits of fluorochromes were classified and analyzed for significance with the Fisher exact test. rESWT significantly increased new bone formation at all time points over the 6-week study period. Intensity of ossification reached a peak after 4 weeks and declined at the end of the study. New bone formation was significantly higher and persisted longer at the ventral cortex, which was located in the direction to the shock wave device, compared with the dorsal cortex, emphasizing the dose-dependent process of ESWT-induced osteogenesis. No traumata, such as hemorrhage, periosteal detachment or microfractures, were observed by histologic and radiologic assessment. This is the first study demonstrating low-energy radial shock waves to induce new bone formation in vivo. Based on our results, repetition of ESWT in 6-week intervals can be recommended. Application to bone regions at increased fracture risk (e.g., in osteoporosis) are possible clinical indications.

Histone deacetylase inhibitors suppress mechanical stress-induced expression of RUNX-2 and ADAMTS-5 through the inhibition of the MAPK signaling pathway in cultured human chondrocytes

OBJECTIVE

To investigate the inhibitory effects and the regulatory mechanisms of histone deacetylase (HDAC) inhibitors on mechanical stress-induced gene expression of runt-related transcription factor (RUNX)-2 and adisintegrin and metalloproteinase with thrombospondin motif (ADAMTS)-5 in human chondrocytes.

METHODS

Human chondrocytes were seeded in stretch chambers at a concentration of 5 × 10(4)cells/chamber. Cells were pre-incubated with or without HDAC inhibitors (MS-275 or trichostatin A; TSA) for 12h, followed by uniaxial cyclic tensile strain (CTS) (0.5Hz, 10% elongation), which was applied for 30 min using the ST-140-10 system (STREX, Osaka, Japan). Total RNA was extracted and the expression of RUNX-2, ADAMTS-5, matrix metalloproteinase (MMP)-3, and MMP-13 at the mRNA and protein levels were examined by real-time polymerase chain reaction (PCR) and immunocytochemistry, respectively. The activation of diverse mitogen-activated protein kinase (MAPK) pathways with or without HDAC inhibitors during CTS was examined by western blotting.

RESULTS

HDAC inhibitors (TSA: 10 nM, MS-275: 100 nM) suppressed CTS-induced expression of RUNX-2, ADAMTS-5, and MMP-3 at both the mRNA and protein levels within 1h. CTS-induced activation of p38 MAPK (p38), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) MAPKs was downregulated by both HDAC inhibitors.

CONCLUSION

The CTS-induced expression of RUNX-2 and ADAMTS-5 was suppressed by HDAC inhibitors via the inhibition of the MAPK pathway activation in human chondrocytes. The results of the current study suggested a novel therapeutic role for HDAC inhibitors against degenerative joint disease such as osteoarthritis.

The morphology of the healing tendon: a comparison of the effects of intrasound therapy and therapeutic pulsed ultrasound

BACKGROUND AND PURPOSE

This study investigated the effects of low- and high-intensity intrasound therapy (LITR and HITR) and low-intensity pulsed ultrasound (LIPUS) on the morphology of the healing tendon.

METHODS

Forty-five male Sprague-Dawley albino rats, randomized into five groups, were further subdivided into groups A and B except Group 1. Groups 2-5 underwent an induced crush injury to the Achilles tendon. The groups were allocated to serve as controls (Group 1), received no treatment (Group 2), LIPUS once daily (Group 3), LITR twice daily (Group 4), and HITR twice daily (Group 5). Treatment commenced 24 hr post-injury over the first 14 days. Subgroup A animals were killed on day 15 and those in subgroup B were killed on day 31. The tendons were excised and processed for histological studies.

RESULTS

LITR and HITR given twice daily caused a significant (p < 0.05) proliferation of tenoblasts in the proliferative phase and enhanced their terminal differentiation to tenocytes in the remodeling phase compared with the untreated and LIPUS-treated groups. LITR and HITR also resulted in a significant increase in the volume fraction of collagen fibers compared with LIPUS.

CONCLUSION

Intrasound therapy has a better morphological effect on the healing tendon than LIPUS and may be an option to consider in the treatment of acute tendon injuries.

Extracorporeal shockwave therapy in musculoskeletal disorders

The sources of shockwave generation include electrohydraulic, electromagnetic and piezoelectric principles. Electrohydraulic shockwaves are high-energy acoustic waves generated under water explosion with high voltage electrode. Shockwave in urology (lithotripsy) is primarily used to disintegrate urolithiasis, whereas shockwave in orthopedics (orthotripsy) is not used to disintegrate tissues, rather to induce tissue repair and regeneration. The application of extracorporeal shockwave therapy (ESWT) in musculoskeletal disorders has been around for more than a decade and is primarily used in the treatment of sports related over-use tendinopathies such as proximal plantar fasciitis of the heel, lateral epicondylitis of the elbow, calcific or non-calcific tendonitis of the shoulder and patellar tendinopathy etc. The success rate ranged from 65% to 91%, and the complications were low and negligible. ESWT is also utilized in the treatment of non-union of long bone fracture, avascular necrosis of femoral head, chronic diabetic and non-diabetic ulcers and ischemic heart disease. The vast majority of the published papers showed positive and beneficial effects. FDA (USA) first approved ESWT for the treatment of proximal plantar fasciitis in 2000 and lateral epicondylitis in 2002. ESWT is a novel non-invasive therapeutic modality without surgery or surgical risks, and the clinical application of ESWT steadily increases over the years. This article reviews the current status of ESWT in musculoskeletal disorders.

Stimulation of bone growth factor synthesis in human osteoblasts and fibroblasts after extracorporeal shock wave application

BACKGROUND

Nonunion is a common problem in Orthopedic Surgery. In the recent years alternatives to the standard surgical procedures were tested clinically and in vitro. Extracorporeal shock wave therapy (ESWT) showed promising results in both settings. We hypothesized that in target tissue cells from nonunions like fibroblasts and osteoblasts ESWT increases the release of bone growth factors.

METHODS

Fibroblasts and osteoblasts were suspended in 3 ml cryotubes and subjected to 250/500 shock waves at 25 kV using an experimental electrohydraulic lithotripter. After ESWT, cell viability was determined and cells were seeded at 1 × 10(5) cells in 12 well plates. After 24, 48, and 72 h cell number was determined and supernatant was frozen. The levels of growth factors FGF-2 and TGF-β(1) were examined using ELISA. A control group was treated equally without receiving ESWT.

RESULTS

After 24 h there was a significant increase in FGF-2 levels (p < 0.05) with significant correlation to the number of impulses (p < 0.05) observed. TGF-β(1) showed a time-dependent increase with a peak at 48 h which was not significantly different from the control group.

CONCLUSIONS

FGF-2, an important growth factor in new bone formation, was shown to be produced by human fibroblasts and osteoblasts after treatment with ESWT. These findings demonstrate that ESWT is able to cause bone healing through a molecular way by inducing growth factor synthesis.

Proteomic analysis of human mesenchymal stromal cells derived from adipose tissue undergoing osteoblast differentiation

BACKGROUND AIMS

Stem cells derived from human adipose tissue (ASC) have the capacity for renewal, are easily obtained and have plasticity properties that allow them to differentiate into several cell types, including osteoblast cells. With the aim of understanding the issue of the osteogenic process and finding reliable biomarkers in cells undergoing the osteogeneic differentiation process, this work took advantage of a proteomic approach to identify proteins involved in osteogenesis.

METHODS

For this purpose, ASC were analyzed under three conditions: S0, in the absence of stimulation; S1, with 2 weeks of osteogenic medium stimulation; and S2, with 4 weeks of osteogenic medium stimulation. The identification of ASC was carried out by flow cytometry using antibodies specific to known undifferentiated stem cell-surface markers. Cell viability, enzymatic activity, mineral deposition, collagen structure and production and gene analyzes were evaluated for each condition.

RESULTS

Phenotypic modifications were observed during the in vitro osteogenic differentiation process by two-dimensional (2-D) differential image gel electrophoresis (DIGE). The proteins were identified by mass espectrometry in tandem (MS/MS) analyzes using Matrix-assisted laser desorption/ionization with TOF/TOF is a tandem mass spectrometry method where two time-of-flight mass spectrometers are used consecutively (MALDI-TOF/TOF). A total of 51 differentially expressed proteins was identified when comparing the three observed conditions. Sixteen different spots were identified in the S0 stage compared with S2, while 28 different spots were found in S2 compared with S0. S1 expressed seven different spots compared with S0 and S2.

CONCLUSIONS

These findings suggest the involvement of several proteins directly related to the osteogenic pathway, which can be used to improve understanding of the osteogenic process.

Unfocused extracorporeal shock waves induce anabolic effects in rat bone

BACKGROUND

Extracorporeal shock waves are known to stimulate the differentiation of mesenchymal stem cells toward osteoprogenitors and induce the expression of osteogenic-related growth hormones. The aim of this study was to investigate if and how extracorporeal shock waves affected new bone formation, bone microarchitecture, and the mechanical properties of bone in a healthy rat model, in order to evaluate whether extracorporeal shock wave therapy might be a potential treatment for osteoporosis.

METHODS

Thirteen rats received 1000 electrohydraulically generated unfocused extracorporeal shock waves to the right tibia. The contralateral, left tibia was not treated and served as a control. At two, seven, twenty-one, and forty-nine days after administration of the shock waves, in vivo single-photon-emission computed tomography (SPECT) scanning was performed to measure new bone formation on the basis of uptake of technetium-labeled methylene diphosphonate ((99m)Tc-MDP) (n = 6). Prior to and forty-nine days after the extracorporeal shock wave therapy, micro-computed tomography (micro-CT) scans were made to examine the architectural bone changes. In addition, mechanical testing, microcrack, and histological analyses were performed.

RESULTS

Extracorporeal shock waves induced a strong increase in (99m)Tc-MDP uptake in the treated tibia compared with the uptake in the untreated, control tibia. Micro-CT analysis showed that extracorporeal shock waves stimulated increases in both trabecular and cortical volume, which resulted in higher bone stiffness compared with that of the control tibiae. Histological analysis showed intramedullary soft-tissue damage and de novo bone with active osteoblasts and osteoid in the bone marrow of the legs treated with extracorporeal shock waves. Microcrack analysis showed no differences between the treated and control legs.

CONCLUSIONS

This study shows that a single treatment with extracorporeal shock waves induces anabolic effects in both cancellous and cortical bone, leading to improved biomechanical properties. Furthermore, treatment with extracorporeal shock waves results in transient damage to the bone marrow, which might be related to the anabolic effects. After further examination and optimization, unfocused extracorporeal shock waves might enable local treatment of skeletal sites susceptible to fracture.