Stimulation of growth factor synthesis by electric and electromagnetic fields

Magnetic hydrogel applications in articular cartilage tissue engineering

Articular cartilage defects afflict millions of individuals worldwide, presenting a significant challenge due to the tissue's limited self-repair capability and anisotropic nature. Hydrogel-based biomaterials have emerged as promising candidates for scaffold production in artificial cartilage construction, owing to their water-rich composition, biocompatibility, and tunable properties. Nevertheless, conventional hydrogels typically lack the anisotropic structure inherent to natural cartilage, impeding their clinical and preclinical applications. Recent advancements in tissue engineering (TE) have introduced magnetically responsive hydrogels, a type of intelligent hydrogel that can be remotely controlled using an external magnetic field. These innovative materials offer a means to create the desired anisotropic architecture required for successful cartilage TE. In this review, we first explore conventional techniques employed for cartilage repair and subsequently delve into recent breakthroughs in the application and utilization of magnetic hydrogels across various aspects of articular cartilage TE.

Enhanced Proliferation and Differentiation of Human Osteoblasts by Remotely Controlled Magnetic-Field-Induced Electric Stimulation Using Flexible Substrates

With the progressive aging of the population, bone fractures are an increasing major health concern. Diverse strategies are being studied to reduce the recovery times using nonaggressive treatments. Electrical stimulation (either endogenous or externally applied electric pulses) has been found to be effective in accelerating bone cell proliferation and differentiation. However, the direct insertion of electrodes into tissues can cause undesirable inflammation or infection reactions. As an alternative, magnetoelectric heterostructures (wherein magnetic fields are applied to induce electric polarization) could be used to achieve electric stimulation without the need for implanted electrodes. Here, we develop a magnetoelectric platform based on flexible kapton/FeGa/P(VDF-TrFE) (flexible substrate/magnetostrictive layer/ferroelectric layer) heterostructures for remote magnetic-field-induced electric field stimulation of human osteoblast cells. We show that the use of flexible supports overcomes the clamping effects that typically occur when analogous magnetoelectric structures are grown onto rigid substrates (which preclude strain transfer from the magnetostrictive to the ferroelectric layers). The study of the diverse proliferation and differentiation markers evidence that in all the stages of bone formation (cell proliferation, extracellular matrix maturation, and mineralization), the electrical stimulation of the cells results in a remarkably better performance. The results pave the way for novel strategies for remote cell stimulation based on flexible platforms not only in bone regeneration but also in many other applications where electrical cell stimulation may be beneficial (e.g., neurological diseases or skin regeneration).

Biophysical control of plasticity and patterning in regeneration and cancer

Cells and tissues display a remarkable range of plasticity and tissue-patterning activities that are emergent of complex signaling dynamics within their microenvironments. These properties, which when operating normally guide embryogenesis and regeneration, become highly disordered in diseases such as cancer. While morphogens and other molecular factors help determine the shapes of tissues and their patterned cellular organization, the parallel contributions of biophysical control mechanisms must be considered to accurately predict and model important processes such as growth, maturation, injury, repair, and senescence. We now know that mechanical, optical, electric, and electromagnetic signals are integral to cellular plasticity and tissue patterning. Because biophysical modalities underly interactions between cells and their extracellular matrices, including cell cycle, metabolism, migration, and differentiation, their applications as tuning dials for regenerative and anti-cancer therapies are being rapidly exploited. Despite this, the importance of cellular communication through biophysical signaling remains disproportionately underrepresented in the literature. Here, we provide a review of biophysical signaling modalities and known mechanisms that initiate, modulate, or inhibit plasticity and tissue patterning in models of regeneration and cancer. We also discuss current approaches in biomedical engineering that harness biophysical control mechanisms to model, characterize, diagnose, and treat disease states.

Electrical Stimulation of Human Mesenchymal Stem Cells on Conductive Substrates Promotes Neural Priming

Electrical stimulation (ES) within a conductive scaffold is potentially beneficial in encouraging the differentiation of stem cells toward a neuronal phenotype. To improve stem cell-based regenerative therapies, it is essential to use electroconductive scaffolds with appropriate stiffnesses to regulate the amount and location of ES delivery. Herein, biodegradable electroconductive substrates with different stiffnesses are fabricated from chitosan-grafted-polyaniline (CS-g-PANI) copolymers. Human mesenchymal stem cells (hMSCs) cultured on soft conductive scaffolds show a morphological change with significant filopodial elongation after electrically stimulated culture along with upregulation of neuronal markers and downregulation of glial markers. Compared to stiff conductive scaffolds and non-conductive CS scaffolds, soft conductive CS-g-PANI scaffolds promote increased expression of microtubule-associated protein 2 (MAP2) and neurofilament heavy chain (NF-H) after application of ES. At the same time, there is a decrease in the expression of the glial markers glial fibrillary acidic protein (GFAP) and vimentin after ES. Furthermore, the elevation of intracellular calcium [Ca2+ ] during spontaneous, cell-generated Ca2+ transients further suggests that electric field stimulation of hMSCs cultured on conductive substrates can promote a neural-like phenotype. The findings suggest that the combination of the soft conductive CS-g-PANI substrate and ES is a promising new tool for enhancing neuronal tissue engineering outcomes.

Harmonizing Magnetic Mitohormetic Regenerative Strategies: Developmental Implications of a Calcium-Mitochondrial Axis Invoked by Magnetic Field Exposure

Mitohormesis is a process whereby mitochondrial stress responses, mediated by reactive oxygen species (ROS), act cumulatively to either instill survival adaptations (low ROS levels) or to produce cell damage (high ROS levels). The mitohormetic nature of extremely low-frequency electromagnetic field (ELF-EMF) exposure thus makes it susceptible to extraneous influences that also impinge on mitochondrial ROS production and contribute to the collective response. Consequently, magnetic stimulation paradigms are prone to experimental variability depending on diverse circumstances. The failure, or inability, to control for these factors has contributed to the existing discrepancies between published reports and in the interpretations made from the results generated therein. Confounding environmental factors include ambient magnetic fields, temperature, the mechanical environment, and the conventional use of aminoglycoside antibiotics. Biological factors include cell type and seeding density as well as the developmental, inflammatory, or senescence statuses of cells that depend on the prior handling of the experimental sample. Technological aspects include magnetic field directionality, uniformity, amplitude, and duration of exposure. All these factors will exhibit manifestations at the level of ROS production that will culminate as a unified cellular response in conjunction with magnetic exposure. Fortunately, many of these factors are under the control of the experimenter. This review will focus on delineating areas requiring technical and biological harmonization to assist in the designing of therapeutic strategies with more clearly defined and better predicted outcomes and to improve the mechanistic interpretation of the generated data, rather than on precise applications. This review will also explore the underlying mechanistic similarities between magnetic field exposure and other forms of biophysical stimuli, such as mechanical stimuli, that mutually induce elevations in intracellular calcium and ROS as a prerequisite for biological outcome. These forms of biophysical stimuli commonly invoke the activity of transient receptor potential cation channel classes, such as TRPC1.

Enhanced Cell Viability and Migration of Primary Bovine Annular Fibrosus Fibroblast-like Cells Induced by Microsecond Pulsed Electric Field Exposure

This study is the first to report the enhancement of cell migration and proliferation induced by in vitro microsecond pulsed electric field (μsPEF) exposure of primary bovine annulus fibrosus (AF) fibroblast-like cells. AF primary cells isolated from fresh bovine intervertebral disks (IVDs) are exposed to 10 and 100 μsPEFs with different numbers of pulses and applied electric field strengths. The results indicate that 10 μs-duration pulses induce reversible electroporation, while 100 μs pulses induce irreversible electroporation of the cells. Additionally, μsPEF exposure increased AF cell proliferation up to 150% while increasing the average migration speed by 0.08 μm/min over 24 h. The findings suggest that the effects of PEF exposure on cells are multifactorial-depending on the duration, intensity, and number of pulses used in the stimulation. This highlights the importance of optimizing the μsPEF parameters for specific cell types and applications. For instance, if the goal is to induce cell death for cancer treatment, then high numbers of pulses can be used to maximize the lethal effects. On the other hand, if the goal is to enhance cell proliferation, a combination of the number of pulses and the applied electric field strength can be tuned to achieve the desired outcome. The information gleaned from this study can be applied in the future to in vitro cell culture expansion and tissue regeneration.

The Developmental Implications of Muscle-Targeted Magnetic Mitohormesis: A Human Health and Longevity Perspective

Muscle function reflects muscular mitochondrial status, which, in turn, is an adaptive response to physical activity, representing improvements in energy production for de novo biosynthesis or metabolic efficiency. Differences in muscle performance are manifestations of the expression of distinct contractile-protein isoforms and of mitochondrial-energy substrate utilization. Powerful contractures require immediate energy production from carbohydrates outside the mitochondria that exhaust rapidly. Sustained muscle contractions require aerobic energy production from fatty acids by the mitochondria that is slower and produces less force. These two patterns of muscle force generation are broadly classified as glycolytic or oxidative, respectively, and require disparate levels of increased contractile or mitochondrial protein production, respectively, to be effectively executed. Glycolytic muscle, hence, tends towards fibre hypertrophy, whereas oxidative fibres are more disposed towards increased mitochondrial content and efficiency, rather than hypertrophy. Although developmentally predetermined muscle classes exist, a degree of functional plasticity persists across all muscles post-birth that can be modulated by exercise and generally results in an increase in the oxidative character of muscle. Oxidative muscle is most strongly correlated with organismal metabolic balance and longevity because of the propensity of oxidative muscle for fatty-acid oxidation and associated anti-inflammatory ramifications which occur at the expense of glycolytic-muscle development and hypertrophy. This muscle-class size disparity is often at odds with common expectations that muscle mass should scale positively with improved health and longevity. Brief magnetic-field activation of the muscle mitochondrial pool has been shown to recapitulate key aspects of the oxidative-muscle phenotype with similar metabolic hallmarks. This review discusses the common genetic cascades invoked by endurance exercise and magnetic-field therapy and the potential physiological differences with regards to human health and longevity. Future human studies examining the physiological consequences of magnetic-field therapy are warranted.

Recent advances of cellular stimulation with triboelectric nanogenerators

Triboelectric nanogenerators (TENGs) are new energy collection devices that have the characteristics of high efficiency, low cost, miniaturization capability, and convenient manufacture. TENGs mainly utilize the triboelectric effect to obtain mechanical energy from organisms or the environment, and this mechanical energy is then converted into and output as electrical energy. Bioelectricity is a phenomenon that widely exists in various cellular processes, including cell proliferation, senescence, apoptosis, as well as adjacent cells' communication and coordination. Therefore, based on these features, TENGs can be applied in organisms to collect energy and output electrical stimulation to act on cells, changing their activities and thereby playing a role in regulating cellular function and interfering with cellular fate, which can further develop into new methods of health care and disease intervention. In this review, we first introduce the working principle of TENGs and their working modes, and then summarize the current research status of cellular function regulation and fate determination stimulated by TENGs, and also analyze their application prospects for changing various processes of cell activity. Finally, we discuss the opportunities and challenges of TENGs in the fields of life science and biomedical engineering, and propose a variety of possibilities for their potential development direction.

Targeting Adenosine Signalling in Knee Chondropathy: The Combined Action of Polydeoxyribonucleotide and Pulsed Electromagnetic Fields: A Current Concept Review

Chondropathy of the knee is one of the most frequent degenerative cartilage pathologies with advancing age. Scientific research has, in recent years, advanced new therapies that target adenosine A2 receptors, which play a significant role in human health against many disease states by activating different protective effects against cell sufferance and damage. Among these, it has been observed that intra-articular injections of polydeoxyribonucleotides (PDRN) and Pulsed Electromagnetic Fields (PEMF) can stimulate the adenosine signal, with significant regenerative and healing effects. This review aims to depict the role and therapeutic modulation of A2A receptors in knee chondropathy. Sixty articles aimed at providing data for our study were included in this review. The present paper highlights how intra-articular injections of PDRN create beneficial effects by reducing pain and improving functional clinical scores, thanks to their anti-inflammatory action and the important healing and regenerating power of the stimulation of cell growth, production of collagen, and the extracellular matrix. PEMF therapy is a valid option in the conservative treatment of different articular pathologies, including early OA, patellofemoral pain syndrome, spontaneous osteonecrosis of the knee (SONK), and in athletes. PEMF could also be used as a supporting therapy after an arthroscopic knee procedure total knee arthroplasty to reduce the post-operative inflammatory state. The proposal of new therapeutic approaches capable of targeting the adenosine signal, such as the intra-articular injection of PDRN and the use of PEMF, has shown excellent beneficial results compared to conventional treatments. These are presented as an extra weapon in the fight against knee chondropathy.

Electrochemical control of bone microstructure on electroactive surfaces for modulation of stem cells and bone tissue engineering

Controlling stem cell behavior at the material interface is crucial for the development of novel technologies in stem cell biology and regenerative medicine. The composition and presentation of bio-factors on a surface strongly influence the activity of stem cells. Herein, we designed an electroactive surface that mimics the initial process of trabecular bone formation, by immobilizing chondrocyte-derived plasma membrane nanofragments (PMNFs) on its surface for rapid mineralization within 2 days. Moreover, the electroactive surface was based on the conducting polymer polypyrrole (PPy), which enabled dynamic control of the presentation of PMNFs on the surface via electrochemical redox switching, further resulting in the formation of bone minerals with different morphologies. Furthermore, bone minerals with contrasting surface morphologies had differential effects on the differentiation of human bone marrow-derived stem cells (hBMSCs) cultured on the surface. Together, this electroactive surface showed multifunctional characteristics, not only allowing dynamic control of PMNF presentation but also promoting the formation of bone minerals with different morphologies within 2 days. This electroactive substrate could be valuable for more precise control of stem cell growth and differentiation, and further development of more suitable microenvironments containing bone apatite for housing a bone marrow stem cell niche, such as biochips/bone-on-chips.

Improving Biocompatibility for Next Generation of Metallic Implants

The increasing need for joint replacement surgeries, musculoskeletal repairs, and orthodontics worldwide prompts emerging technologies to evolve with healthcare's changing landscape. Metallic orthopaedic materials have a shared application history with the aerospace industry, making them only partly efficient in the biomedical domain. However, suitability of metallic materials in bone tissue replacements and regenerative therapies remains unchallenged due to their superior mechanical properties, eventhough they are not perfectly biocompatible. Therefore, exploring ways to improve biocompatibility is the most critical step toward designing the next generation of metallic biomaterials. This review discusses methods of improving biocompatibility of metals used in biomedical devices using surface modification, bulk modification, and incorporation of biologics. Our investigation spans multiple length scales, from bulk metals to the effect of microporosities, surface nanoarchitecture, and biomolecules such as DNA incorporation for enhanced biological response in metallic materials. We examine recent technologies such as 3D printing in alloy design and storing surface charge on nanoarchitecture surfaces, metal-on-metal, and ceramic-on-metal coatings to present a coherent and comprehensive understanding of the subject. Finally, we consider the advantages and challenges of metallic biomaterials and identify future directions.

Harnessing electromagnetic fields to assist bone tissue engineering

Bone tissue engineering (BTE) emerged as one of the exceptional means for bone defects owing to it providing mechanical supports to guide bone tissue regeneration. Great advances have been made to facilitate the success of BTE in regenerating bone within defects. The use of externally applied fields has been regarded as an alternative strategy for BTE. Electromagnetic fields (EMFs), known as a simple and non-invasive therapy, can remotely provide electric and magnetic stimulation to cells and biomaterials, thus applying EMFs to assist BTE would be a promising strategy for bone regeneration. When combined with BTE, EMFs improve cell adhesion to the material surface by promoting protein adsorption. Additionally, EMFs have positive effects on mesenchymal stem cells and show capabilities of pro-angiogenesis and macrophage polarization manipulation. These advantages of EMFs indicate that it is perfectly suitable for representing the adjuvant treatment of BTE. We also summarize studies concerning combinations of EMFs and diverse biomaterial types. The strategy of combining EMFs and BTE receives encouraging outcomes and holds a promising future for effectively treating bone defects.

Electrical stimulation therapy and rotary jet-spinning scaffold to treat bone defects

The combination of electrical stimulation (ES) and bone tissue engineering (BTE) has been successful in treatments of bone regeneration. This study evaluated the effects of ES combined with PCL + β-TCP 5% scaffolds obtained by rotary jet spinning (RJS) in the regeneration of bone defects in the calvaria of Wistar rats. We used 120 animals with induced bone defects divided into 4 groups (n = 30): (C) without treatment; (S) with PCL+ β-TCP 5% scaffold; (ES) treated with ES (10 μA/5 min); (ES + S) with PCL + β-TCP 5% scaffold. The ES occurred twice a week during the entire experimental period. Cell viability (in vitro: Days 3 and 7) and histomorphometric, histochemical, and immunohistochemical (in vivo; Days 30, 60, and 90) analysis were performed. In vitro, ES + S increased cell viability after Day 7 of incubation. In vivo, it was observed modulation of inflammatory cells in ES therapy, which also promoted blood vessels proliferation, and increase of collagen. Moreover, ES therapy played a role in osteogenesis by decreasing ligand kappa B nuclear factor-TNFSF11 (RANKL), increasing alkaline phosphatase (ALP), and decreasing the tartarate-resistant acid phosphatase. The combination of ES with RJS scaffolds may be a promising strategy for bone defects regeneration, since the therapy controlled inflammation, favored blood vessels proliferation, and osteogenesis, which are important processes in bone remodeling.

The Effect of Different Frequencies of Pulsed Electromagnetic Fields on Cartilage Repair of Adipose Mesenchymal Stem Cell-Derived Exosomes in Osteoarthritis

BACKGROUND

The intra-articular injection of mesenchymal stem cell (MSC)-derived exosomes has already been proved to reverse osteoarthritic cartilage degeneration. Pulsed electromagnetic field (PEMF) has been found to regulate the biogenic function of MSCs. However, the effect of PEMF on MSC-derived exosomes has not yet been characterized. The aim of this study was to elucidate the regulatory role of different frequencies of PEMF in promoting the osteoarthritic cartilage regeneration of MSC-derived exosomes.

METHODS

The adipose tissue-derived MSCs (AMSCs) were extracted from the epididymal fat of healthy rats and further exposed to the PEMF at 1 mT amplitude and a frequency of 15, 45, and 75 Hz, respectively, in an incubator. The chondrocytes were treated with interlukin-1β (IL-1β) and the regenerative effect of co-culturing with PEMF-exposed AMSC-derived exosomes was assessed via Western blot, quantitative polymerase chain reaction, and ELISA assays. A rat model of osteoarthritis was established by anterior cruciate ligament transection (ACLT) surgery and received 4 times intra-articular injection of PEMF-exposed AMSC-derived exosomes once a week. After 8 weeks, the knee joint specimens of rats were collected for micro-computed tomography and histologic analyses.

RESULTS

PEMF-exposed AMSC-derived exosomes could be endocytosed with IL-1β-induced chondrocytes. Compared with the AMSC-derived exosomes alone, the PEMF-exposed AMSC-derived exosomes substantially suppressed the inflammation and extracellular matrix degeneration of IL-1β-induced chondrocytes as shown by higher expression of transcripts and proteins of COL2A1, SOX9, and ACAN and lower expression of MMP13 and caspase-1. Of these, the 75-Hz PEMF presented a more significant inhibitive effect than the 15-Hz and 45-Hz PEMFs. Furthermore, the intra-articular injection of 75-Hz PEMF-exposed exosomes could obviously increase the number of tibial epiphyseal trabeculae, lead to a remarkable decrease in Osteoarthritis Research Society International score, and upregulate the COL2A1 and ACAN protein level of the degenerated cartilage.

CONCLUSION

The present study demonstrated that PEMF stimulation could effectively promote the regeneration effects of AMSC-derived exosomes on osteoarthritic cartilage. Compared with other frequency parameters, the PEMF at a frequency of 75 Hz showed a superior positive effect on AMSC-derived exosomes in suppressing the IL-1β-induced chondrocyte inflammation and extracellular matrix catabolism, as well as the osteoarthritic cartilage degeneration.

IC-Type Electric stimulation for delayed bone healing: monocentric evaluation over eight years of experience

Electrostimulation is suggested to positively influence bone healing for delayed unions of both fractures and osteotomies. This monocentric series aims to retrospectively assess the outcome of electrostimulation treatment for delayed union after traumatic fractures or knee osteotomy. Patients treated with electrostimulation for delayed union (no bony union on radiographic imaging at 90 days after osteotomy or fracture treatment) over an 8-year period were screened. The delay of treatment, success rate, revision rate and demographic data (age, sex, location of fracture, presence of osteosynthesis materials) were investigated. A questionnaire assessed objective (nicotine abuse, NRS pain assessment, activity levels) and subjective (comfort, usability, cost-effectiveness) aspects. Electrostimulation delivered radiographic healing in 75% of the fracture group and 66% of the osteotomy group. No statistical significant difference (N=136) in success rate was found for age, sex, presence of osteosynthesis material, delay or fracture location. Success rate did differ significantly with pain, activity level and smoking (p<0.05). Reflective questions to patients were answered mostly positively. The use of electrostimulation for the delayed union of fractures and knee osteotomies delivers high healing rates avoiding the burden of surgical reintervention. It is generally well received by the patient. No difference in success rate was found between sex, age or fracture location, nor did the delay of therapy onset or presence of osteosynthesis material seem to affect the success rate. Smoking had a negative influence on the efficacy of bone electrostimulation.

Synthetic electrospun nanofibers as a supportive matrix in osteogenic differentiation of induced pluripotent stem cells

Continuous remodeling is not able to repair large bone defects. Bone tissue engineering is aimed to repair these defects by creating bone grafts. To do this, several technologies and biomaterials have been employed to fabricate an in vivo-like supportive matrix. Electrospinning is a versatile technique to fabricate porous matrices with interconnected pores and high surface area, replicating in vivo microenvironment. Electrospun scaffolds have been used in a large number of studies to provide a matrix for bone regeneration and osteogenic differentiation of stem cells such as induced pluripotent stem cells (iPSCs). Electrospinning uses both natural and synthetic polymers, either alone or in combination, to fabricate scaffolds. Among them, synthetic polymers have had a great promise in bone regeneration and repair. They allow the fabrication of biocompatible and biodegradable scaffolds with high mechanical properties, suitable for bone engineering. Furthermore, several attempts have done to increase the osteogenic properties of these scaffolds. This paper reviewed the potential of synthetic electrospun scaffolds in osteogenic differentiation of iPSCs. In addition, the approaches to improve the osteogenic differentiation of these scaffolds are addressed.

Aseptic nonunion of the tibia treated by plating and bone grafting: retrospective study about 40 cases

Objective

The objective of this study was to evaluate the clinical and radiological results of the treatment of aseptic nonunion of the tibia by plating and bone grafting.

Material and Methods

This retrospective study included 40 patients with aseptic nonunion of the tibia, treated in the Trauma-Orthopedic department B4 of CHU Hassan II in Fez-Morocco. The average age was 41 years (range 25–60 years). The initial fractures were in the middle third of the tibia for the majority of our patients. We used the ASAMI criteria to assess the results.

Results

We found 45 patients with aseptic nonunion of the tibia who were treated by the same surgical team and followed in postoperative consultation for a fixed period of 10 months. Three patients lost to follow-up and two patients refused the treatment. In 37 patients (92.5%), union was obtained after a mean delay of 4.3 months (range 3–7 months). The average time from initial treatment to treatment for nonunion was eight months (range 6–10 months). According to the ASAMI classification, bone results were excellent in 26, good in 8, fair in 3 and poor in 3; functional results were excellent in 10, good in 16, fair in 11 and poor in 3.

Conclusions

Our study suggests that the combination of screwed plate and autograft in the treatment of aseptic nonunion of the tibia has provided satisfactory results. A well-codified management of the initial fracture remains the gold key to prevent the occurrence of pseudarthrosis.

The healing effect of pulsed magnetic field on burn wounds

A burn is one of the most difficult injuries people can face.The primary pathology is coagulation necrosis resulting from tissue damage.Many wound care products have been developed to be used in situations such as the poor general condition of the patient and lack of solid area to be grafted. However, the high costs of these products make their use complicated.In this study, the effect of PEMF on cutaneous wound healing in an animal burn model was evaluated and the dose and duration of the magnetic field should be discussed for this effect to occur. Animals were divided into five groups including eight each (n = 40) (Groups 1, 2, 3, 4, 5).Group 1 was the control group; received no treatment after second-degree burn wound. Group 2 received daily wound care with saline. Group 3 received daily wound care with pomade containing mupirocin. Group 4 received Pulsed Electromagnetic Field signal for 60 min (1.5 m T and 40 Hz for seven days and Group 5 also received PEMF signal for 60 min the same frequency and intensity for14 days. Microscopically, second-degree burn wounds were successfully detected in all rats. Histopathological examination results in no significant difference between groups in neutrophil infiltration. The difference between the groups in vascularization was statistically significant between Group II and Group V (p < 0.001) and between Group I and Group V (p = 0.005) Epithelialization was present in 75% of the rats in Group V, while no epithelialization was observed in any of the other groups. In conclusion, we observed a significant improvement in the stasis zone of the group receiving Pulsed Electromagnetic Field for two weeks.

Biophysical Modulation of Mesenchymal Stem Cell Differentiation in the Context of Skeletal Repair

A prominent feature of the skeleton is its ability to remodel in response to biophysical stimuli and to repair under varied biophysical conditions. This allows the skeleton considerable adaptation to meet its physiological roles of stability and movement. Skeletal cells and their mesenchymal precursors exist in a native environment rich with biophysical signals, and they sense and respond to those signals to meet organismal demands of the skeleton. While mechanical strain is the most recognized of the skeletal biophysical stimuli, signaling phenomena also include fluid flow, hydrostatic pressure, shear stress, and ion-movement-related electrokinetic phenomena including, prominently, streaming potentials. Because of the complex interactions of these electromechanical signals, it is difficult to isolate the significance of each. The application of external electrical and electromagnetic fields allows an exploration of the effects of these stimuli on cell differentiation and extra-cellular matrix formation in the absence of mechanical strain. This review takes a distinctly translational approach to mechanistic and preclinical studies of differentiation and skeletal lineage commitment of mesenchymal cells under biophysical stimulation. In vitro studies facilitate the examination of isolated cellular responses while in vivo studies permit the observation of cell differentiation and extracellular matrix synthesis.

Biophysical Stimulation in Athletes' Joint Degeneration: A Narrative Review

Osteoarthritis (OA) is the most prevalent degenerative joint disease and the main cause of pain and disability in elderly people. OA currently represents a significant social health problem, since it affects 250 million individuals worldwide, mainly adults aged over 65. Although OA is a multifactorial disease, depending on both genetic and environmental factors, it is reported that joint degeneration has a higher prevalence in former athletes. Repetitive impact and loading, joint overuse and recurrent injuries followed by a rapid return to the sport might explain athletes' predisposition to joint articular degeneration. In recent years, however, big efforts have been made to improve the prevention and management of sports injuries and to speed up the athletes' return-to-sport. Biophysics is the study of biological processes and systems using physics-based methods or based on physical principles. Clinical biophysics has recently evolved as a medical branch that investigates the relationship between the human body and non-ionizing physical energy. A physical stimulus triggers a biological response by regulating specific intracellular pathways, thus acting as a drug. Preclinical and clinical trials have shown positive effects of biophysical stimulation on articular cartilage, subchondral bone and synovia. This review aims to assess the role of pulsed electromagnetic fields (PEMFs) and extracorporeal shockwave therapy (ESWT) in the prevention and treatment of joint degeneration in athletes.

Pulsed electromagnetic fields after intramedullary nailing of tibial fractures: a case control study

PURPOSE

To compare clinical and functional outcomes of two groups of patients undergoing reduction and nailing fixation for diaphyseal fractures of the tibia with (PEMF group) and without (control group) post-operative pulsed electromagnetic field (PEMF) application.

METHODS

This is a retrospective study on 50 patients (mean age 43.3 years, 28 males and 22 females) with diaphyseal tibial fractures managed between 2017 and 2019. Twenty-five patients underwent reduction, nailing fixation, and PEMF application post-operatively (PEMF group) and 25 patients underwent nailing fixation. Radiographic imaging assessment was performed every month until fracture healing had been evident. Use of analgesics, fracture healing time, post-operative lower limb alignment, and post-operative complications were recorded. Patients were asked about return to preinjury activity. All patients were assessed at 3 months and at an average follow-up of 13 months. The VAS scale and Johner-Wruhs criteria were used for pain assessment and functional recovery, respectively.

RESULTS

Comparing groups, VAS values were significantly lower in the PEMF group at three months and comparable at one year. The patients in the PEMF group took an average of 4.1 months to resume their preinjury activities, and control patients took an average of 5.3 months (P < 0.0001). According to the Johner-Wruhs score, the effective rate was 100% (25/25) in the PEMF group and 92% (23/25) in the control group (P = 0.14).

CONCLUSIONS

PEMF application after intramedullary nailing is safe and reduces post-operative pain, use of analgesics, and the time of healing fracture. At one year, there is no difference in outcome measures, regardless of PEMF application.

Therapy of pancreatic cancer with alternating electric fields: Limitations of the method

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumor with a poor prognosis. More effective treatment options are urgently needed. The use of physical and weak alternating electric fields (TTFields) can inhibit cell division of PDAC carcinoma and is currently being investigated in clinical trials. Here, we analyzed this new physical treatment under non-ideal conditions such as may occur during patient treatment. Three established human PDAC cell lines BxPC-3, gemcitabine-resistant BxPC-3 (BxGem), AsPC-1, and a non-malignant primary pancreatic cell line CRL-4023 were treated with TTFields in vitro. MTT assays, electrical impedance measurement, cell staining with Annexin V/7AAD followed by FACS analysis, digital image analysis and immunohistochemistry were performed. Treatment with TTFields smaller than 0.7 V/cm and field lines in the direction of mitotic spindle orientation significantly inhibited proliferation of all PDAC cells at 150 kHz, but significantly increased viability of AsPC-1 cells at all frequencies between 100 kHz and 300 kHz and that of BxPC-3 and BxGem cells at 250 kHz. Apoptosis or necrosis were not induced. Non-malignant CRL-4023 cells were not affected at 150 kHz. TTFields damaged PDAC cell lines but even favored their viability at very weak field strength and unfavorable frequency or inadequate field direction.

Electrical therapies act on the Ca2+ /CaM signaling pathway to enhance bone regeneration with bioactive glass [S53P4] and allogeneic grafts

This study aimed to investigate the application of low-intensity electrostimulation (ES) and electromagnetic stimulation (EM) associated with bioactive glass (BG) or allogeneic grafts (BB) in bone regeneration. A cell viability test on osteoblasts (UMR-106) was performed in the presence of BB and BG grafts associated with ES (10 μA/5 min) and EM (500 Hz/2 min). Critical defects (25 mm² ) in calvaria were generated in male Wistar rats, and bone regeneration was evaluated on the 30th, 60th, and 120th days after surgery. Cell proliferation increased with the application of ES in both grafts and after EM with BG. Bone remodeling was more effective using the allogeneic graft in both therapies, with increased angiogenesis, osteoblast proliferation, and OPN expression in the BB + EM group. A higher number of osteoblasts and osteoclasts, and an increase in bone sialoprotein, Runx-2, and Opn gene expression were found in the BB + ES group. The BG graft associated with EM therapy had an increased proliferation of osteoblasts and increased expression of Runx-2 and Opn. Groups that had BG and ES therapy had increased numbers of osteoblasts, osteoclasts, and increased OPN expression. The expression of voltage-gated calcium channels increased in groups with ES, while calmodulin expression increased in therapies without grafting. ES and EM therapies favored the repair of bone defects upon grafting by improving angiogenesis, osteogenic gene expression, and tissue reorganization. Despite activating different pathways, both therapies increased the intracellular concentrations of calmodulin, leading to cell proliferation and bone regeneration.

A Prospective Comparative Study of Pulsed High-Intensity Laser Therapy and Pulsed Electromagnetic Field on Chronic Nonspecific Low Back Pain

Objective: This study explored the different effects of pulsed high-intensity laser therapy (HILT) versus pulsed electromagnetic field (EMF) in the treatment of chronic nonspecific low back pain (ChNsLBP). Methods: Between August and December 2019, 51 ChNsLBP participants with a mean age of 35.2 ± 8.6 years were enrolled in this prospective comparative study. At random, they were divided into three groups, 17 in each; HILT, EMF, and controls. HILT group was recruited for Nd:YAG laser using the following parameters: a wavelength of 1064 nm, fluency of 610-810 mJ, frequency of 10-40 Hz, average power of 10.5 W, and 120 μs short pulse duration in scanning mode. All groups received the treatment twice a week for 8 consecutive weeks. They were assessed for the modified Oswestry disability index (MODI), pain disability index (PDI), visual analog scale (VAS), and lumbar flexion range of motion (flex ROM) before and after 8 weeks of study program. Results: The results showed greater improvement in the HILT group (VAS, PDI, MODI, and lumbar flex ROM, p = 0.001) than the EMF group (VAS, p = 0.002, PDI, p = 0.045, MODI, p = 0.002, and lumbar flex ROM, p = 0.042), with significant difference between the two groups in favor of the HILT group (p ˂ 0.05). Conclusions: Depending on the results of the study, both HILT and EMF are useful physiotherapy modalities in the treatment of ChNsLBP with HILT exhibiting better outcomes than EMF. Clinical recommendations should be highlighted to instigate the use of HILT in the management of musculoskeletal disorders, distinctively ChNsLBP.

A comparison of alendronate to varying magnitude PEMF in mitigating bone loss and altering bone remodeling in skeletally mature osteoporotic rats

Pulsed electromagnetic field (PEMF) treatments stimulate bone formation activities though further work is needed to optimize its therapeutic benefit. PEMF can generate local potential gradients and electric currents that have been suggested to mimic bone electrochemical responses to load. In line with this reasoning, a recent publication reported that PEMF application on isolated bone tissue induced detectable micro-vibrations (doi:https://doi.org/10.1109/TMAG.2016.2515069). To determine the ability of PEMF to intervene in a rat model of osteoporosis, we tested its effect on trabecular and cortical bone following ovariectomy. Four PEMF treatments, with increasing sinusoidal amplitude rise with time (3850 Hz pulse frequency and 15 Hz repetition rate at 10 tesla/sec (T/s), 30 T/s, 100 T/s, or 300 T/s), were compared to the efficacy of an osteoporosis drug, alendronate, in reducing levels of trabecular bone loss in the proximal tibia. Herein, the novel findings from our study are: (1) 30 T/s PEMF treatment approached the efficacy of alendronate in reducing trabecular bone loss, but differed from it by not reducing bone formation rates; and (2) 30 T/s and 100 T/s PEMF treatments imparted measurable alterations in lacunocanalicular features in cortical bone, consistent with osteocyte sensitivity to PEMF in vivo. The efficacy of specific PEMF doses may relate to their ability to modulate osteocyte function such that the 30 T/s, and to a lesser extent 100 T/s, doses preferentially antagonize trabecular bone resorption while stimulating bone formation. Thus, PEMF treatments of specific magnetic field magnitudes exert a range of measurable biological effects in trabecular and cortical bone tissue in osteoporotic rats.

Electromagnetic radiation: a new charming actor in hematopoiesis?

INTRODUCTION

Electromagnetic waves play indispensable roles in life. Many studies addressed the outcomes of Electromagnetic field (EMF) on various biological functions such as cell proliferation, gene expression, epigenetic alterations, genotoxic, and carcinogenic effects, and its therapeutic applications in medicine. The impact of EMF on bone marrow (BM) is of high importance; however, EMF effects on BM hematopoiesis are not well understood.

AREAS COVERED

Publications in English were searched in ISI Web of Knowledge and Google Scholar with no restriction on publication date. A literature review has been conducted on the consequences of EMF exposure on BM non-hematopoietic stem cells, mesenchymal stem cells, and the application of these waves in regenerative medicine. Human blood cells such as lymphocytes, red blood cells and their precursors are altered qualitatively and quantitatively following electromagnetic radiation. Therefore, studying the impact of EMF on related signaling pathways in hematopoiesis and hematopoietic stem cell (HSC) differentiation could give a better insight into its efficacy on hematopoiesis and its potential therapeutic usage.

EXPERT OPINION

In this review, authors evaluated the possible biologic consequences of EMF on the hematopoiesis process in addition to its probable application in the treatment of hematologic disorders.

Promising application of Pulsed Electromagnetic Fields (PEMFs) in musculoskeletal disorders

Increasing evidence suggests that an exogenous electromagnetic field might be involved in many biologic processes which are of great importance for therapeutic interventions. Pulsed electromagnetic fields (PEMFs) are known to be a noninvasive, safe and effective therapy agent without apparent side effects. Numerous studies have shown that PEMFs possess the potential to become a stand-alone or adjunctive treatment modality for treating musculoskeletal disorders. However, several issues remain unresolved. Prior to their widely clinical application, further researches from well-designed, high-quality studies are still required to standardize the treatment parameters and derive the optimal protocol for health-care decision making. In this review, we aim to provide current evidence on the mechanism of action, clinical applications, and controversies of PEMFs in musculoskeletal disorders.

Graphene Family Nanomaterial Reinforced Magnesium-Based Matrix Composites for Biomedical Application: A Comprehensive Review

Together with the enhancement of the load-bearing implant process for bone substitution and reproduction, an increasing requirement was observed concerning biodegradable magnesium and its alloys with lighter density and outstanding characteristics. Regardless of the current great potential of Mg utilization currently, the broader use of Mg alloys continues to be constrained by several natural causes, such as low resistance of corrosion, inadequate mechanical integrity during the healing process, and poor antibacterial performance. In this perspective, Mg-based composite encapsulated within graphene family nanomaterials (GFNs) such as graphene (Gr), graphene oxide (GO), graphene nanoplatelets (GNPs), and reduced graphene oxide (rGO) as reinforcement agents present great antibacterial activity, as well as cellular response and depicted numerous benefits for biomedical use. Magnesium matrix nanocomposites reinforced with GFNs possess enhanced mechanical properties and high corrosion resistance (low concentration graphene). It is worth noting that numerous elements including the production technique of the Mg-based composite containing GFNs and the size, distribution, and amounts of GFNs in the Mg-based matrix have a crucial role in their properties and applications. Then, the antibacterial mechanisms of GFN-based composite are briefly described. Subsequently, the antibacterial and strengthening mechanisms of GFN-embedded Mg-based composites are briefly described. This review article is designed to wrap up and explore the most pertinent research performed in the direction of Mg-based composites encapsulated within GFNs. Feasible upcoming investigation directions in the field of GFN-embedded Mg-based composites are discussed in detail.

Pulsed Electromagnetic Field Stimulation of Bone Healing and Joint Preservation: Cellular Mechanisms of Skeletal Response

The US FDA has approved pulsed electromagnetic fields (PEMFs) as a safe and effective treatment for nonunions of bone. Despite its clinical use, the mechanisms of action of electromagnetic stimulation of the skeleton have been elusive. Recently, cell membrane receptors have been identified as the site of action of PEMF and provide a mechanistic rationale for clinical use. This review highlights key processes in cell responses to PEMF as follows: (1) signal transduction through A_2A and A₃ adenosine cell membrane receptors and (2) dose-response effects on the synthesis of structural and signaling extracellular matrix (ECM) components. Through these actions, PEMF can increase the structural integrity of bone and cartilage ECM, enhancing repair, and alter the homeostatic balance of signaling cytokines, producing anti-inflammatory effects. PEMFs exert a proanabolic effect on the bone and cartilage matrix and a chondroprotective effect counteracting the catabolic effects of inflammation in the joint environment. Understanding of PEMF membrane targets, and of the specific intracellular pathways involved, culminating in the synthesis of ECM proteins and reduction in inflammatory cytokines, should enhance confidence in the clinical use of PEMF and the identification of clinical conditions likely to be affected by PEMF exposure.

Electrical Stimulation in the Treatment of Lymphedema and Associated Skin Ulcers

Background: Lymphedema is a disorder in which lymph accumulates in the interstitial spaces due to poor lymphatic flow resulting from hypoplasia or aplasia of the lymphatic vessels, or to morpho-functional alterations that impair lymphatic flow. Lymphedema is a debilitating condition associated initially with inflammation that then degenerates into hardening of affected tissues and the formation of ulcers on the skin of affected limbs. No definitive treatment is available. The only therapy for lymphedema consists of physiotherapy, surgery, and compression to reduce impairment, which only treats the symptoms, not the causes. A possible new therapy that could reinforce the treatment of lymphedema progression and complications is electrical stimulation (ES). Many studies underline the effects of electric currents on the different cell mechanisms associated with disease. Methods and Results: In this review, we summarize the effects of ES on the molecular and cellular processes involved in the pathophysiology of lymphedema, highlighting their therapeutic potential for edema reduction, ulcer repair, and restoration of lymphatic flow in vitro and in vivo. Conclusions: ES exerts its effect on the main stages that characterize lymphedema, from its onset to ulcer formation. There are few evidences on lymphatic models and more molecular studies are needed to understand the mechanism of action of this application in the treatment of lymphedema.

Neurogenesis-on-Chip: Electric field modulated transdifferentiation of human mesenchymal stem cell and mouse muscle precursor cell coculture

A number of bioengineering strategies, using biophysical stimulation, are being explored to guide the human mesenchymal stem cells (hMScs) into different lineages. In this context, we have limited understanding on the transdifferentiation of matured cells to another functional-cell type, when grown with stem cells, in a constrained cellular microenvironment under biophysical stimulation. While addressing such aspects, the present work reports the influence of the electric field (EF) stimulation on the phenotypic and functionality modulation of the coculture of murine myoblasts (C2C12) with hMScs [hMSc:C2C12=1:10] in a custom designed polymethylmethacrylate (PMMA) based microfluidic device with in-built metal electrodes. The quantitative and qualitative analysis of the immunofluorescence study confirms that the cocultured cells in the conditioned medium with astrocytic feed, exhibit differentiation towards neural-committed cells under biophysical stimulation in the range of the endogenous physiological electric field strength (8 ± 0.06  mV/mm). The control experiments using similar culture protocols revealed that while C2C12 monoculture exhibited myotube-like fused structures, the hMScs exhibited the neurosphere-like clusters with SOX2, nestin, βIII-tubulin expression. The electrophysiological study indicates the significant role of intercellular calcium signalling among the differentiated cells towards transdifferentiation. Furthermore, the depolarization induced calcium influx strongly supports neural-like behaviour for the electric field stimulated cells in coculture. The intriguing results are explained in terms of the paracrine signalling among the transdifferentiated cells in the electric field stimulated cellular microenvironment. In summary, the present study establishes the potential for neurogenesis on-chip for the coculture of hMSc and C2C12 cells under tailored electric field stimulation, in vitro.

Magnesium matrix nanocomposites for orthopedic applications: A review from mechanical, corrosion, and biological perspectives

Magnesium (Mg) and some of its alloys have attracted extensive interests for biomedical applications as they exhibit biodegradability and low elastic modulus that is closer to natural bones than the currently used metallic implant materials such as titanium (Ti) and its alloys, stainless steels, and cobalt-chromium (Co-Cr) alloys. However, the rapid degradation of Mg alloys and loss of their mechanical integrity before sufficient bone healing impede their clinical application. Our literature review shows that magnesium matrix nanocomposites (MMNCs) reinforced with nanoparticles possess enhanced strength, high corrosion resistance, and good biocompatibility. This article provides a detailed analysis of the effects of nanoparticle reinforcements on the mechanical properties, corrosion behavior, and biocompatibility of MMNCs as promising biodegradable implant materials. The governing equations to quantitatively predict the mechanical properties and underlying synergistic strengthening mechanisms in MMNCs are elucidated. The potential, recent advances, challenges and future research directions in relation to nanoparticles reinforced MMNCs are highlighted. STATEMENT OF SIGNIFICANCE: Critically reviewing magnesium metal matrix nanocomposites (MMNCs) for the biomedical application. Clear definitions of strengthening mechanisms using reinforcement particle in the magnesium matrix, as there were controversial in governing equations of strengthening parameters. Providing better understanding of the effect of particle size, volume fraction, interfacial bonding, and uniform dispersion of reinforcement particles on MMNCs.

Stem Cell Based Drug Delivery for Protection of Auditory Neurons in a Guinea Pig Model of Cochlear Implantation

Background: The success of a cochlear implant (CI), which is the standard therapy for patients suffering from severe to profound sensorineural hearing loss, depends on the number and excitability of spiral ganglion neurons (SGNs). Brain-derived neurotrophic factor (BDNF) has a protective effect on SGNs but should be applied chronically to guarantee their lifelong survival. Long-term administration of BDNF could be achieved using genetically modified mesenchymal stem cells (MSCs), but these cells should be protected – by ultra-high viscous (UHV-) alginate (‘alginate-MSCs’) – from the recipient immune system and from uncontrolled migration.

Methods: Brain-derived neurotrophic factor-producing MSCs were encapsulated in UHV-alginate. Four experimental groups were investigated using guinea pigs as an animal model. Three of them were systemically deafened and (unilaterally) received one of the following: (I) a CI; (II) an alginate-MSC-coated CI; (III) an injection of alginate-embedded MSCs into the scala tympani followed by CI insertion and alginate polymerization. Group IV was normal hearing, with CI insertion in both ears and a unilateral injection of alginate-MSCs. Using acoustically evoked auditory brainstem response measurements, hearing thresholds were determined before implantation and before sacrificing the animals. Electrode impedance was measured weekly. Four weeks after implantation, the animals were sacrificed and the SGN density and degree of fibrosis were evaluated.

Results: The MSCs survived being implanted for 4 weeks in vivo. Neither the alginate-MSC injection nor the coating affected electrode impedance or fibrosis. CI insertion with and without previous alginate injection in normal-hearing animals resulted in increased hearing thresholds within the high-frequency range. Low-frequency hearing loss was additionally observed in the alginate-injected and implanted cochleae, but not in those treated only with a CI. In deafened animals, the alginate-MSC coating of the CI significantly prevented SGN from degeneration, but the injection of alginate-MSCs did not.

Conclusion: Brain-derived neurotrophic factor-producing MSCs encapsulated in UHV-alginate prevent SGNs from degeneration in the form of coating on the CI surface, but not in the form of an injection. No increase in fibrosis or impedance was detected. Further research and development aimed at verifying long-term mechanical and biological properties of coated electrodes in vitro and in vivo, in combination with chronic electrical stimulation, is needed before the current concept can be tested in clinical trials.

Electrical stimulation-based bone fracture treatment, if it works so well why do not more surgeons use it?

BACKGROUND

Electrical stimulation (EStim) has been proven to promote bone healing in experimental settings and has been used clinically for many years and yet it has not become a mainstream clinical treatment.

METHODS

To better understand this discrepancy we reviewed 72 animal and 69 clinical studies published between 1978 and 2017, and separately asked 161 orthopedic surgeons worldwide about their awareness, experience, and acceptance of EStim for treating fracture patients.

RESULTS

Of the 72 animal studies, 77% reported positive outcomes, and the most common model, bone, fracture type, and method of administering EStim were dog, tibia, large bone defects, and DC, respectively. Of the 69 clinical studies, 73% reported positive outcomes, and the most common bone treated, fracture type, and method of administration were tibia, delayed/non-unions, and PEMF, respectively. Of the 161 survey respondents, most (73%) were aware of the positive outcomes reported in the literature, yet only 32% used EStim in their patients. The most common fracture they treated was delayed/non-unions, and the greatest problems with EStim were high costs and inconsistent results.

CONCLUSION

Despite their awareness of EStim's pro-fracture healing effects few orthopedic surgeons use it in their patients. Our review of the literature and survey indicate that this is due to confusion in the literature due to the great variation in methods reported, and the inconsistent results associated with this treatment approach. In spite of this surgeons seem to be open to using this treatment if advancements in the technology were able to provide an easy to use, cost-effective method to deliver EStim in their fracture patients.

Engineered 3D printed poly(ɛ-caprolactone)/graphene scaffolds for bone tissue engineering

Scaffolds are important physical substrates for cell attachment, proliferation and differentiation. Multiple factors could influence the optimal design of scaffolds for a specific tissue, such as the geometry, the materials used to modulate cell proliferation and differentiation, its biodegradability and biocompatibility. The optimal design of a scaffold for a specific tissue strongly depends on both materials and manufacturing processes. Previous studies of human adipose-derived stem cells (hADSCs) seeded on poly(ε-caprolactone) (PCL)/graphene scaffolds have proved that the addition of small concentrations of graphene to PCL scaffolds improves cell proliferation. Based on such results, this paper further investigates, for the first time, both in vitro and in vivo characteristics of 3D printed PCL/graphene scaffolds. Scaffolds were evaluated from morphological, biological and short term immune response points of view. Results show that the produced scaffolds induce an acceptable level of immune response, suggesting high potential for in vivo applications. Finally, the scaffolds were used to treat a rat calvaria critical size defect with and without applying micro electrical stimulation (10 μA). Quantification of connective and new bone tissue formation and the levels of ALP, RANK, RANKL, OPG were considered. Results show that the use of scaffolds containing graphene and electrical stimulation seems to increase cell migration and cell influx, leading to new tissue formation, well-organized tissue deposition and bone remodelling.

A Pulsed Electromagnetic Field Therapy Device for Non-Specific Low Back Pain: A Pilot Randomized Controlled Trial

Introduction

Low back pain (LBP) poses a significant burden of disease worldwide, and identifying safe and effective non-pharmacologic treatment options for LBP is a research priority. The aim of this study was to pilot a clinical trial of a portable pulsed electromagnetic field (PEMF) therapy device for subjects with mixed duration non-specific LBP.

Methods

This work was a randomized, double-blind, sham-controlled, parallel-group study conducted at a chiropractic school outpatient clinic. The primary end point was functional capacity measured by the Oswestry Disability Index (ODI) at baseline, 6 weeks, and 12 weeks. Analysis was conducted on the intent-to-treat population and as a trend of change in pain scores over time using the Freidman test of repeated measures.

Results

Forty-two participants were randomized to receive usual care plus PEMF therapy or usual care plus sham, and 25 completed the study. Significant improvements in ODI scores from baseline to week 6 were reported in the experimental group (χ² = 14.68, p < 0.001, compared with patients in the sham group, χ² = 4.00, p = 0.135, n.s.). This difference persisted at week-12 follow-up. Adverse events were rare and mild.

Conclusion

It is feasible to conduct a clinical trial of a PEMF therapy device for non-specific LBP. This work shows that the device was safe and provides preliminary evidence of effectiveness in improving function in patients with non-specific LBP.

Trial Registration

ClinicalTrials.gov identifier, NCT03053375.

Funding

Aerotel Ltd.

The effects of electromagnetic fields on cultured human retinal pigment epithelial cells

A great deal of evidence has confirmed that electromagnetic fields (EMFs) can affect the central nervous system. In this study, cultured neonatal human retinal pigment epithelial (hRPE) cells were exposed to pulsed EMF of 1 mT intensity and 50 Hz frequency 8 h daily for 3 days. In addition to cell proliferation and cell death assays, immunocytochemistry for RPE65, PAX6, nestin, and cytokeratin 8/18 proteins were performed. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) was performed for NES, PAX6, RPE65, and ACTA2 gene expression. Exposed hRPE cells did not demonstrate significant change in terms of cytomorphology, cell proliferation, or cell death. Protein expression of PAX6 was decreased in treated cells compared to controls and remained unchanged for RPE65, cytokeratin 8/18, and nestin. Gene expressions of NES, RPE65, and PAX6 were decreased in treated cells as compared to controls. Gene expression of ACTA2 did not significantly change. In conclusion, viability of cultivated neonatal hRPE cells did not change after short exposure to a safe dose of pulsed EMF albeit that both gene and protein expressions of retinal progenitor cell markers were reduced. Whether longer exposure durations that are being constantly produced by widely-used electronic devices may induce significant changes in these cells, needs further investigation. Bioelectromagnetics. 39:585-594, 2018. © 2018 Wiley Periodicals, Inc.

Effect of pulsed electromagnetic field on mandibular fracture healing: A randomized control trial, (RCT)

INTRODUCTION

Currently, the pulsed electromagnetic field (PEMF) method is utilized for the treatment of nonunion long bone fractures. Considering the established effect of the PEMF on the acceleration of the bone healing process, we conducted this study to evaluate the effect of PEMF on the healing process in mandibular bone fractures.

MATERIAL AND METHODS

This research was a randomized control trial (RCT) study. The sample consisted of patients with a mandibular fracture who were hospitalized in order to receive closed reduction treatment. The participants were randomly selected and then sequentially divided into two groups of 16 participants each (controls = 16, cases = 16). The patients in the control group received conventional therapy without any extra treatment, while the patients in the case group received PEMF therapy in addition to conventional therapy. For the PEMF therapy, patients in the case group received immediate post-surgery PEMF therapy for 6 h. Next, they received 3 h of exposure for the next 6 d, and finally, the same process was repeated for 1.5 h for post-surgery days 8-13. The maxillomandibular fixation (MMF) device was removed at post-surgery week 4. The patients in the control group, however, did not receive any extra treatment. The efficiency of the treatment modalities was evaluated clinically and radiographically. For the radiographical assessment, we employed a direct digital panoramic machine to calculate the computerized density of the bone, and those measurements were used for comparison of the results between the control group and the study patients.

RESULTS

There was no significant difference in the mean bone density values between the two groups (P > 0.05). However, the percentage of changes in bone density of the two groups revealed that the case group had insignificant decreases at post-surgery day 14 and a significant increase at post-surgery day 28 compared with the control group (P < 0.05). After releasing the MMF, a bimanual mobility test of the fractured segments showed the stability of the segments in all patients. In the case group, the mouth opening was significantly more stable than that of the control group (P < 0.05).

CONCLUSION

PEMF therapy postoperatively leads to increased bone density, faster recovery, increased formation of new bone, a further opening of the mouth, and decreased pain.

Do electrical current and laser therapies improve bone remodeling during an orthodontic treatment with corticotomy?

OBJECTIVES

Evaluate the bone remodeling during orthodontic movement with corticotomy when submitted to low-intensity electrical stimulation application (microcurrent-MC) and low-level laser therapy (LLLT).

MATERIAL AND METHODS

One hundred and fifty Wistar rats were divided into the following 5 groups: (C) submitted to tooth movement; (Cort) tooth movement/corticotomy; (Cort-L) tooth movement/corticotomy/laser AsGaAl 808 nm (4.96J/50s); (Cort-Mc) tooth movement/corticotomy/microcurrent (10 μA/5 min); (Cort-L-Mc) tooth movement/corticotomy and laser/microcurrent alternated. Inflammation, angiogenesis, and osteogenesis were evaluated in the periodontal ligament (PDL) and alveolar bone on the 7th, 14th, and 21st days of orthodontic movement.

RESULTS

The quantification of inflammatory infiltrate, angiogenesis and expression of TGF-β1, VEGF, and collagen type I were favorably modulated by the application of therapies such as low-level laser therapy (LLLT), MC, or both combined. However, electrical stimulation increased fibroblasts, osteoclasts and RANK numbers, birefringent collagen fiber organization, and BMP-7 and IL-6 expression.

CONCLUSIONS

Low-level laser therapy (LLLT) and MC application both improved the process of bone remodeling during orthodontic treatment with corticotomy. Still, electrical current therapy promoted a more effective tooth displacement but presented expected root resorption similar to all experimental treatments.

CLINICAL RELEVANCE

It is important to know the effects of minimally invasive therapies on cellular and molecular elements involved in the bone remodeling of orthodontic treatment associated with corticotomy surgery, in order to reduce the adverse effects in the use of this technique and to establish a safer clinical routine.

Carbon Nanotubes and Graphene as Nanoreinforcements in Metallic Biomaterials: a Review

Current challenges in existing metallic biomaterials encourage undertaking research in the development of novel materials for biomedical applications. This paper critically reviews the potential of carbon nanotubes (CNT) and graphene as nanoreinforcements in metallic biomaterials for bone tissue engineering. Unique and remarkable mechanical, electrical, and biological properties of these carbon nanomaterials allow their use as secondary-phase reinforcements in monolithic biomaterials. The nanoscale dimensions and extraordinarily large surface areas of CNT and graphene make them suitable materials for purposeful reaction with living organisms. However, the cytocompatibility of CNT and graphene is still a controversial issue that impedes advances in utilizing these promising materials in clinical orthopedic applications. The interaction of CNT and graphene with biological systems including proteins, nucleic acids, and human cells is critically reviewed to assess their cytocompatibity in vitro and in vivo. It is revealed that composites reinforced with CNT and graphene show enhanced adhesion of osteoblast cells, which subsequently promotes bone tissue formation in vivo. This potential is expected to pave the way for developing ground-breaking technologies in regenerative medicine and bone tissue engineering. In addition, current progress and future research directions are highlighted for the development of CNT and graphene reinforced implants for bone tissue engineering.

Biophysical stimulation of bone and cartilage: state of the art and future perspectives

INTRODUCTION

Biophysical stimulation is a non-invasive therapy used in orthopaedic practice to increase and enhance reparative and anabolic activities of tissue.

METHODS

A sistematic web-based search for papers was conducted using the following titles: (1) pulsed electromagnetic field (PEMF), capacitively coupled electrical field (CCEF), low intensity pulsed ultrasound system (LIPUS) and biophysical stimulation; (2) bone cells, bone tissue, fracture, non-union, prosthesis and vertebral fracture; and (3) chondrocyte, synoviocytes, joint chondroprotection, arthroscopy and knee arthroplasty.

RESULTS

Pre-clinical studies have shown that the site of interaction of biophysical stimuli is the cell membrane. Its effect on bone tissue is to increase proliferation, synthesis and release of growth factors. On articular cells, it creates a strong A_2A and A₃ adenosine-agonist effect inducing an anti-inflammatory and chondroprotective result. In treated animals, it has been shown that the mineralisation rate of newly formed bone is almost doubled, the progression of the osteoarthritic cartilage degeneration is inhibited and quality of cartilage is preserved. Biophysical stimulation has been used in the clinical setting to promote the healing of fractures and non-unions. It has been successfully used on joint pathologies for its beneficial effect on improving function in early OA and after knee surgery to limit the inflammation of periarticular tissues.

DISCUSSION

The pooled result of the studies in this review revealed the efficacy of biophysical stimulation for bone healing and joint chondroprotection based on proven methodological quality.

CONCLUSION

The orthopaedic community has played a central role in the development and understanding of the importance of the physical stimuli. Biophysical stimulation requires care and precision in use if it is to ensure the success expected of it by physicians and patients.

Functionalized-ferroelectric-coating-driven enhanced biomineralization and protein-conformation on metallic implants

In the context of bone regeneration, it is important to have platforms that with appropriate stimuli can support the attachment and direct the growth, proliferation and differentiation of cells.

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.

Electrical stimulation: Complementary therapy to improve the performance of grafts in bone defects?

The limitations of bone reconstruction techniques have stimulated the tissue engineering for the repair of large bone defects using osteoconductive materials and osteoinductive agents. This study evaluated the effects of low intensity electric current on the inorganic bovine graft in calvaria defects. Bone defects were performed with piezoelectric system in the calvaria of Wistar rats divided into four groups (n = 24): (C) without grafting and without electrical stimulation; (E) with grafting; (MC) without grafting and submitted to electrical stimulation; (MC + E) with grafting and submitted to electrical stimulation. Inflammatory, angiogenic and osteogenic events during bone repair at the 10th, 30th, 60th, and 90th days were considered. Several inflammatory markers demonstrated the efficacy of grafting in reducing inflammation, particularly when subjected to electrical stimulation. Angiogenesis and collagen organization were more evident by electrical stimulation application on the grafts. Moreover, the osteogenic cell differentiation process indicated that the application of microcurrent on grafting modulated the homeostasis of bone remodeling. It is concluded that microcurrent favored the performance of grafts in calvarial rat model. Low-intensity electrical current might improve the osteoconductive property of grafting in bone defects. Therefore, electrical current becomes an option as complementary therapy in clinical trials involving bone surgeries and injuries. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 924-932, 2019.

Efficacy of extremely low-frequency magnetic field in fibromyalgia pain: A pilot study

The purpose of this pilot study was to determine the efficacy of an extremely low-frequency magnetic field (ELF-MF) in decreasing chronic pain in fibromyalgia (FM) patients. Thirty-seven females were recruited and randomized into two groups: one group was first exposed to systemic ELF-MF therapy (100 microtesla, 1 to 80 Hz) and then to sham therapy, and the other group received the opposite sequence of intervention. Pain, FM-related symptoms, and the ability to perform daily tasks were measured using the Visual Analog Scale, Fibromyalgia Impact Questionnaire (FIQ), Fibromyalgia Assessment Scale (FAS), and Health Assessment Questionnaire (HAQ) at baseline, end of first treatment cycle, beginning of second treatment cycle (after 1 mo washout), end of second treatment cycle, and end of 1 mo follow-up. ELF-MF treatment significantly reduced pain, which increased on cessation of therapy but remained significantly lower than baseline levels. Short-term benefits were also observed in FIQ, FAS, and HAQ scores, with less significant effects seen in the medium term. ELF-MF therapy can be recommended as part of a multimodal approach for mitigating pain in FM subjects and improving the efficacy of drug therapy or physiotherapy.

Effects of single and combined low frequency electromagnetic fields and simulated microgravity on gene expression of human mesenchymal stem cells during chondrogenesis

INTRODUCTION

Low frequency electromagnetic fields (LF-EMF) and simulated microgravity (SMG) have been observed to affect chondrogenesis. A controlled bioreactor system was developed to apply LF-EMF and SMG singly or combined during chondrogenic differentiation of human mesenchymal stem cells (hMSCs) in 3D culture.

MATERIAL AND METHODS

An external motor gear SMG bioreactor was combined with magnetic Helmholtz coils for EMF (5 mT; 15 Hz). Pellets of hMSCs (±TGF-β3) were cultured (P5) under SMG, LF-EMF, LF-EMF/SMG and control (1 g) conditions for 3 weeks. Sections were stained with safranin-O and collagen type II. Gene expression was evaluated by microarray and real-time polymerase chain reaction analysis.

RESULTS

Simulated microgravity application significantly changed gene expression; specifically, COLXA1 but also COL2A1, which represents the chondrogenic potential, were reduced (p < 0.05). Low frequency electromagnetic fields application showed no gene expression changes on a microarray basis. LF-EMF/SMG application obtained significant different expression values from cultures obtained under SMG conditions with a re-increase of COL2A1, therefore rescuing the chondrogenic potential, which had been lowered by SMG.

CONCLUSIONS

Simulated microgravity lowered hypertrophy but also the chondrogenic potential of hMSCs. Combined LF-EMF/SMG provided a rescue effect of the chondrogenic potential of hMSCs although no LF-EMF effect was observed under optimal conditions. The study provides new insights into how LF-EMF and SMG affect chondrogenesis of hMSCs and how they generate interdependent effects.

Repetitive transcranial magnetic stimulation for the treatment of cognitive impairment in frontotemporal dementia: an open-label pilot study

BACKGROUND

Frontotemporal dementia (FTD) is one of the most frequent dementia types in patients under 65 years of age. Currently, no therapy can effectively improve the cognitive deficits associated with FTD. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive method of inducing brain plasticity with therapeutic potential in neurodegenerative diseases. The purpose of this study was to evaluate the effect of rTMS on cognitive, behavioral, and emotional function in FTD.

METHODS

Nine patients (seven women, four men, mean age 61.7±10.1 years) with the behavioral variant of FTD, one with nonfluent/agrammatic variant primary progressive aphasia, and one with progressive nonfluent aphasia (subtypes of FTD) underwent 10 daily sessions of 10 Hz rTMS over the bilateral dorsolateral prefrontal cortex. Cognitive and behavioral assessments were administered before and after therapy.

RESULTS

After rTMS, the Montreal Cognitive Assessment and letter and digit cancellation test scores, as well as reading time and error number in the Stroop test improved. The caregivers' impression of the daily functioning of patients improved in the Frontal Behavioral Inventory scores. These changes were not paralleled by an improvement of mood.

CONCLUSION

The results indicate that rTMS may improve the cognitive performance of patients with FTD and warrant sham-controlled trials.