Electromagnetic fields (EMFs) and adenosine receptors modulate prostaglandin E(2) and cytokine release in human osteoarthritic synovial fibroblasts

Application of electrostimulation and magnetic stimulation in patients with optic neuropathy: A mechanistic review

Visual impairment caused by optic neuropathies is irreversible because retinal ganglion cells (RGCs), the specialized neurons of the retina, do not have the capacity for self-renewal and self-repair. Blindness caused by optic nerve neuropathies causes extensive physical, financial, and social consequences in human societies. Recent studies on different animal models and humans have established effective strategies to prevent further RGC degeneration and replace the cells that have deteriorated. In this review, we discuss the application of electrical stimulation (ES) and magnetic field stimulation (MFS) in optic neuropathies, their mechanisms of action, their advantages, and limitations. ES and MFS can be applied effectively in the field of neuroregeneration. Although stem cells are becoming a promising approach for regenerating RGCs, the inhibitory environment of the CNS and the long visual pathway from the optic nerve to the superior colliculus are critical barriers to overcome. Scientific evidence has shown that adjuvant treatments, such as the application of ES and MFS help direct thetransplanted RGCs to extend their axons and form new synapses in the central nervous system (CNS). In addition, these techniques improve CNS neuroplasticity and decrease the inhibitory effects of the CNS. Possible mechanisms mediating the effects of electrical current on biological tissues include the release of anti-inflammatory cytokines, improvement of microcirculation, stimulation of cell metabolism, and modification of stem cell function. ES and MFS have the potential to promote angiogenesis, direct axon growth toward the intended target, and enhance appropriate synaptogenesis in optic nerve regeneration.

Unraveling the transcriptome profile of pulsed electromagnetic field stimulation in bone regeneration using a bioreactor-based investigation platform

INTRODUCTION

Human mesenchymal stem cells (hMSCs) sense and respond to biomechanical and biophysical stimuli, yet the involved signaling pathways are not fully identified. The clinical application of biophysical stimulation including pulsed electromagnetic field (PEMF) has gained momentum in musculoskeletal disorders and bone tissue engineering.

METHODOLOGY

We herein aim to explore the role of PEMF stimulation in bone regeneration by developing trabecular bone-like tissues, and then, culturing them under bone-like mechanical stimulation in an automated perfusion bioreactor combined with a custom-made PEMF stimulator. After selecting the optimal cell seeding and culture conditions for inspecting the effects of PEMF on hMSCs, transcriptomic studies were performed on cells cultured under direct perfusion with and without PEMF stimulation.

RESULTS

We were able to identify a set of signaling pathways and upstream regulators associated with PEMF stimulation and to distinguish those linked to bone regeneration. Our findings suggest that PEMF induces the immune potential of hMSCs by activating and inhibiting various immune-related pathways, such as macrophage classical activation and MSP-RON signaling in macrophages, respectively, while promoting angiogenesis and osteogenesis, which mimics the dynamic interplay of biological processes during bone healing.

CONCLUSIONS

Overall, the adopted bioreactor-based investigation platform can be used to investigate the impact of PEMF stimulation on bone regeneration.

Chronic E. Coli Drug-Resistant Cystitis Treated with a Sequence of Modulated Extremely Low-Frequency Electromagnetic Fields: A Randomized Study of 148 Cases

(1) Background: This study investigated the effects of sequenced electromagnetic fields, modulated at extremely low frequencies and intensities, in the treatment of drug-resistant Escherichia coli (E. coli)-induced chronic bacterial cystitis. (2) Methods: A total of 148 female participants, aged 18 to 80 years diagnosed with chronic bacterial cystitis caused by drug-resistant E. coli, were recruited for this study. Participants were randomly assigned to two groups: an experimental group (n = 74) with osteopathic palpation and assessment treated with a sequence of electromagnetic fields, and a control group (n = 74) receiving a placebo treatment. Both groups were assessed at this study's outset, 4 weeks after eight applications, and at 12 weeks for symptomatic presentation and laboratory parameters. (3) Results: After 4 weeks of treatment, a significant difference was observed between the two groups regarding D-DIMER levels, IL-6 levels, erythrocyte levels, leukocyte levels, and E. coli levels (p < 0.001). By the 12th week, the experimental group continued to exhibit a significant reduction in the examined parameters compared to the control group (p < 0.001). Additionally, the treatment did not induce any side effects in the patients in the experimental group. (4) Conclusions: Treatment with coherently sequenced electromagnetic fields, modulated at an extremely low frequency and intensity, not only appears to provide an effective alternative for the symptoms of chronic bacterial cystitis caused by drug-resistant E. coli but also demonstrates a potent antibacterial effect.

Low-frequency pulsed electromagnetic fields alleviate the condylar cartilage degeneration and synovitis at the early stage of temporomandibular joint osteoarthritis

BACKGROUND

Temporomandibular joint osteoarthritis (TMJOA) is characterized by articular cartilage degeneration and progressive synovitis. How to effectively inhibit TMJOA in the early stage has been a hot topic in the biomedical field. As a non-invasive physiotherapy, pulsed electromagnetic field (PEMF) treatment has shown great potential in the treatment of osteoarthritis (OA) in extremity joints.

OBJECTIVE

This study aims to investigate the biological effect of PEMF intervention on TMJ cartilage degeneration and synovium inflammation at the early stage of TMJOA.

METHODS

PEMF (2.0 mT, 15 Hz, 2 h/day) treatment was given to rats in which TMJOA was induced by applying the unilateral anterior crossbite (UAC). Histological and immunohistochemical staining, TUNEL assay, real-time PCR and western blotting assay were performed to detect the changes of the morphology and the expression of pro-inflammatory and degradative factors in condylar cartilage and synovium.

RESULTS

Obvious condylar cartilage degeneration, characterized by decreased cartilage thickness, degraded cartilage extracellular matrix, increased expression of pro-inflammatory and degradative factors (TNF-α, IL-1β, MMP-13, ADAMTS-5, IL-6, MMP-3, MMP-9 and COL-X) and increased chondrocytes death, was observed in UAC group, accompanied by synovium hyperplasia and up-regulation of pro-inflammatory and degradative factors in synovium. PEMF intervention reversed the decreased cartilage thickness at 3 weeks and degraded cartilage extracellular matrix at 6 weeks. Moreover, the up-regulation of pro-inflammatory, degradative and hypertrophyic factors and chondrocytes death in condylar cartilage induced by UAC were inhibited to some extent. In addition, the synovium hyperplasia and the up-regulation of pro-inflammatory and degradative factors in synovium were inhibited at 3 weeks and 6 weeks.

CONCLUSIONS

Appropriate PEMF stimulation can reverse the loss of cartilage extracellular matrix, the chondrocytes death, the increased expression of pro-inflammatory and degradative factors in cartilage, the decreased cartilage thickness and synovium inflammation induced by UAC at the early stage of TMJOA to some extent. PEMF stimulation may be a promising method in clinical TMJOA treatment.

A novel extracellular vesicles production system harnessing matrix homeostasis and macrophage reprogramming mitigates osteoarthritis

Osteoarthritis (OA) is a degenerative disease that significantly impairs quality of life. There is a pressing need for innovative OA therapies. While small extracellular vesicles (sEVs) show promising therapeutic effects against OA, their limited yield restricts clinical translation. Here, we devised a novel production system for sEVs that enhances both their yield and therapeutic properties. By stimulating mesenchymal stem cells (MSCs) using electromagnetic field (EMF) combined with ultrasmall superparamagnetic iron oxide (USPIO) particles, we procured an augmented yield of EMF-USPIO-sEVs. These vesicles not only activate anabolic pathways but also inhibit catabolic activities, and crucially, they promote M2 macrophage polarization, aiding cartilage regeneration. In an OA mouse model triggered by anterior cruciate ligament transection surgery, EMF-USPIO-sEVs reduced OA severity, and augmented matrix synthesis. Moreover, they decelerated OA progression through the microRNA-99b/MFG-E8/NF-κB signaling axis. Consequently, EMF-USPIO-sEVs present a potential therapeutic option for OA, acting by modulating matrix homeostasis and macrophage polarization.

Effects of the combination of pulsed electromagnetic field with progressive resistance exercise on knee osteoarthritis: A randomized controlled trial

BACKGROUND

Knee osteoarthritis (OA) is a common and disabling disease among the elderly population. The optimal conservative treatment for knee OA is not well established.

OBJECTIVE

This study aimed to assess the effectiveness of pulsed electromagnetic field (PEMF) combined with progressive resistance exercise (PRE) in improving physical function and pain in patients with knee OA.

METHODS

Thirty-four patients with knee OA (17 in each group) participated in a single-blind randomized control study. Patients were randomly assigned to receive 24 sessions of either combined PEMF and PRE (treatment group) or PRE only (control group). Patients were evaluated at pre-treatment, post-treatment (2 months), and at 3-month and 6-month follow-ups using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Numeric Pain Rating Scale (NPRS); walking speed and 5-times chair stand test. Mixed ANOVA was used for statistical analysis with Bonferroni adjustments.

RESULTS

There was no significant group-by-time interaction for any outcome (P> 0.05). However, both groups scored significantly higher on the NPRS and KOOS at post-treatment, 3-, and 6-month follow-up compared to their baseline. Further, both groups completed the 5-times chair stand test and walking speed test with significantly less time at all post-treatment time points than the pre-treatment. None of the study outcomes (NPRS, KOOS, walking speed, and 5 times chair stand) were significantly different between groups at any of the time points.

CONCLUSION

Both treatment options, PRE only versus PRE with PEMF, were equally effective in decreasing pain and improving physical function in patients with knee OA. This would suggest that the optimal parameters for PEMF that may show beneficial effects for knee OA when added to PRE training need to be determined.

Pulsed Electromagnetic Fields Induce Skeletal Muscle Cell Repair by Sustaining the Expression of Proteins Involved in the Response to Cellular Damage and Oxidative Stress

Pulsed electromagnetic fields (PEMF) are employed as a non-invasive medicinal therapy, especially in the orthopedic field to stimulate bone regeneration. However, the effect of PEMF on skeletal muscle cells (SkMC) has been understudied. Here, we studied the potentiality of 1.5 mT PEMF to stimulate early regeneration of human SkMC. We showed that human SkMC stimulated with 1.5 mT PEMF for four hours repeated for two days can stimulate cell proliferation without inducing cell apoptosis or significant impairment of the metabolic activity. Interestingly, when we simulated physical damage of the muscle tissue by a scratch, we found that the same PEMF treatment can speed up the regenerative process, inducing a more complete cell migration to close the scratch and wound healing. Moreover, we investigated the molecular pattern induced by PEMF among 26 stress-related cell proteins. We found that the expression of 10 proteins increased after two consecutive days of PEMF stimulation for 4 h, and most of them were involved in response processes to oxidative stress. Among these proteins, we found that heat shock protein 70 (HSP70), which can promote muscle recovery, inhibits apoptosis and decreases inflammation in skeletal muscle, together with thioredoxin, paraoxonase, and superoxide dismutase (SOD2), which can also promote skeletal muscle regeneration following injury. Altogether, these data support the possibility of using PEMF to increase SkMC regeneration and, for the first time, suggest a possible molecular mechanism, which consists of sustaining the expression of antioxidant enzymes to control the important inflammatory and oxidative process occurring following muscle damage.

The Effect of Extremely Low-Frequency Electromagnetic Fields on Inflammation and Performance-Related Indices in Trained Athletes: A Double-Blinded Crossover Study

Previous investigations have demonstrated the therapeutic advantages of extremely low-frequency electromagnetic fields (ELF-EMFs) in mitigating inflammation and influencing biological processes. We aimed to shed light on the effects of ELF-EMF on recovery rate following high-intensity exercise. Nine male athletes (26.7 ± 6.0 years; 69.6 ± 7.7 kg, VO2peak 57.3 ± 6.8 mL/kg/min) completed five visits in a double-blinded crossover design, performing two consecutive testing days, following a ventilatory thresholds assessment. Following 62 min of high-intensity cycling, participants lay on an ELF-EMF mattress under active (A) and non-active (NA) conditions, immediately post protocol and during the night. Physical performance and blood markers were assessed at baseline and at 60 min (60 P) and 24 h (24 H) post-protocol. The A-condition demonstrated a notable reduction in interleukin-10 (IL-10) concentrations (mean difference = -88%, p = 0.032) and maximal isometric strength of the quadriceps muscles (mean difference = ~8%, p = 0.045) compared to the NA-condition between 60 P and 24 H. In a sensitivity analysis, the A-condition revealed that younger athletes who possessed lower fat mass experienced attenuated inflammation and biochemical responses and improved physical performance. In conclusion, ELF-EMF showed no significant overall effects on performance and inflammation after intense cycling among athletes. Post-hoc analysis revealed modest benefits of ELF-MLF, suggesting a context-dependent impact. Further research with a larger sample size and multiple sessions is needed to confirm the recovery potential of ELF-EMF.

Quantum Molecular Resonance Inhibits NLRP3 Inflammasome/Nitrosative Stress and Promotes M1 to M2 Macrophage Polarization: Potential Therapeutic Effect in Osteoarthritis Model In Vitro

This study aimed to investigate the anti-inflammatory effects of Quantum Molecular Resonance (QMR) technology in an in vitro model of osteoarthritis-related inflammation. The study used THP-1-derived macrophages stimulated with lipopolysaccharide and hyaluronic acid fragments to induce the expression of inflammatory cytokines and nitrosative stress. QMR treatment inhibited COX-2 and iNOS protein expression and activity and reduced NF-κB activity. Furthermore, QMR treatment led to a significant reduction in peroxynitrite levels, reactive nitrogen species that can form during inflammatory conditions, and restored tyrosine nitration values to those similar to sham-exposed control cells. We also investigated the effect of QMR treatment on inflammasome activation and macrophage polarization in THP-1-derived macrophages. Results showed that QMR treatment significantly decreased NLRP3 and activated caspase-1 protein expression levels and downregulated IL-18 and IL-1β protein expression and secretion. Finally, our findings indicate that QMR treatment induces a switch in macrophage polarization from the M1 phenotype to the M2 phenotype.

Electromagnetic fields regulate calcium-mediated cell fate of stem cells: osteogenesis, chondrogenesis and apoptosis

Electromagnetic fields (EMF) are increasing in popularity as a safe and non-invasive therapy. On the one hand, it is widely acknowledged that EMF can regulate the proliferation and differentiation of stem cells, promoting the undifferentiated cells capable of osteogenesis, angiogenesis, and chondroblast differentiation to achieve bone repair purpose. On the other hand, EMF can inhibit tumor stem cells proliferation and promote apoptosis to suppress tumor growth. As an essential second messenger, intracellular calcium plays a role in regulating cell cycle, such as proliferation, differentiation and apoptosis. There is increasing evidence that the modulation of intracellular calcium ion by EMF leads to differential outcomes in different stem cells. This review summarizes the regulation of channels, transporters, and ion pumps by EMF-induced calcium oscillations. It furtherly discusses the role of molecules and pathways activated by EMF-dependent calcium oscillations in promoting bone and cartilage repair and inhibiting tumor stem cells growth.

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.

Pulsed electromagnetic fields improve pain management and clinical outcomes after medial unicompartmental knee arthroplasty: A prospective randomised controlled trial

BACKGROUND

To assess pain relief and clinical outcomes in patients undergoing unicompartmental knee arthroplasty (UKA) stimulated with pulsed electromagnetic fields (PEMFs) compared to a control group.

METHODS

A prospective randomised controlled trial (RCT) was performed in which 72 patients undergoing medial UKA were randomised into a control group or an experimental PEMFs group. The patients allocated to the experimental group were instructed to use PEMFs for 4 h per day for 60 days. They were evaluated before a surgery and then during the time points corresponding to 1 month, 2 months, 6 months, 12 months, and 36 months after the surgery. No placebo group was included in the RCT. Clinical assessment included the Visual Analogue Scale (VAS) for pain, Oxford Knee Score (OKS), the Short Form 36 (SF-36) health survey questionnaire, and joint swelling. During each follow-up visit, the consumption of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) was recorded.

RESULTS

The VAS decreased on follow-up visits in both the groups; a statistically significant difference between the groups was observed during the 6 (p = 0.0297), 12 (p = 0.0003), and 36 months (p = 0.0333) follow-ups in favour of the PEMFs group. One month after UKA, the percentages of patients using NSAIDs in the PEMFs and control group were 71% and 92%, respectively (p = 0.0320). At the 2 months point, 15% of the patients in the PEMFs group used NSAIDs compared to 39% in the control group (p = 0.0317). The objective knee girth evaluation showed a statistically significant difference at 6 (p = 0.0204), 12 (p = 0.0005), and 36 (p = 0.0005) months with improved values observed in the PEMFs group. The subjective assessment of the swelling demonstrated a statistically significant difference at 2 (p = 0.0073), 6 (p = 0.0006), 12 (p = 0.0001), and 36 (p = 0.0011) months with better values noted in the PEMFs group. Last, the OKS result was significant higher in the experimental group during all the follow-ups (1mth: p = 0.0295; 2mths: p = 0.0012; 6mths: p = 0.0001; 12mths: p < 0.0001; 36mths: p = 0.0061).

CONCLUSIONS

The use of PEMFs leads to significant pain relief, better clinical improvement, and lower NSAIDs consumption after medial UKA when compared to the control group.

LEVEL OF EVIDENCE

II.

Small interfering RNAs in the management of human rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) has unclear pathogenesis, but the molecules that feed its inflammatory state are known. Small interfering RNAs (siRNAs) are useful to identify molecular targets and evaluate the efficacy of specific drugs, and can themselves be used for therapeutic purposes.

SOURCES OF DATA

A systematic search of different databases to March 2022 was performed to define the role of siRNAs in RA therapy. Twenty suitable studies were identified.

AREAS OF AGREEMENT

Small interfering RNAs can be useful in the study of inflammatory processes in RA, and identify possible therapeutic targets and drug therapies.

AREAS OF CONTROVERSY

Many genes and cytokines participate in the inflammatory process of RA and can be regulated with siRNA. However, it is difficult to determine whether the responses to siRNAs and other drugs studied in human cells in vitro are similar to the responses in vivo.

GROWING POINTS

Inflammatory processes can be affected by the gene dysregulation of siRNAs on inflammatory cytokines.

AREAS TIMELY FOR DEVELOPING RESEARCH

To date, it is not possible to determine whether the pharmacological response of siRNAs on cells in vitro would be similar to what takes place in vivo for the diseases studied so far.

Diamagnetic Therapy in a Patient with Complex Regional Pain Syndrome Type I and Multiple Drug Intolerance: A Case Report

Complex regional pain syndrome (CRPS) is a neurologic chronic pain condition hard to diagnose and treat, and able to significantly impact the quality of life. Currently, the available multimodal, individualized treatments (i.e., pharmacological and non-pharmacological therapies including invasive procedures) are aimed only at symptom control. Herein, we report a 69-year-old Caucasian female who came to our attention due to a 3-year history of severe (10/10) burning pain in her right ankle, along with oedema and local changes in skin color and temperature, which occurred after the ankle sprain. Previous pharmacological attempts failed due to multiple drug intolerance. Clinical examination confirmed the CRPS type I diagnosis, and a weekly diamagnetic therapy protocol was started since the patient refused further medications and interventional procedures. After 10 weeks of treatment, a significant (p < 0.01) reduction in pain severity and absence of oedema (difference in ankles’ circumference: from 3 cm to 0) were observed, with consequent improvements in quality of life and no adverse events. Although high-quality clinical evidence is still lacking, our case report suggests further investigating the potential use of diamagnetic therapy as a non-invasive and safe adjunctive treatment for CRPS, and as an alternative when patients did not benefit from drugs and/or refuse invasive procedures.

Pulsed Electromagnetic Field Attenuates Osteoarthritis Progression in a Murine Destabilization-Induced Model through Inhibition of TNF-α and IL-6 Signaling

OBJECTIVE

To investigate the anti-inflammatory effects and mechanisms of pulsed electromagnetic field (PEMF) in the treatment of osteoarthritis (OA) in the destabilization of the medial meniscus (DMM) mice.

DESIGN

Ten-week-old male wild-type (WT), interleukin (IL)-6-/- and tumor necrosis factor (TNF)-α-/- mice undergoing DMM surgery were randomly divided into 2 groups (n = 10 each): mice with PEMF exposure and mice with sham PEMF exposure. PEMF (75 Hz, 3.8 mT, 1 h/day) or sham PEMF was applied for 4 weeks. Pain behavior of mice, histological assessment of cartilage and synovium, micro-CT (computed tomography) analysis of bone, real-time polymerase chain reaction, and immunohistochemical staining of cartilage were performed.

RESULTS

After DMM surgery, PEMF had a beneficial effect on pain, cartilage degeneration, synovitis, and trabecular bone microarchitecture in WT mice; these protective effects were reduced in IL-6-/- and TNF-α-/- mice. In addition, PEMF downregulated IL-6 and TNF-α expression in cartilage. PEMF also ameliorated cartilage matrix, chondrocyte apoptosis, and autophagy, while deletion of IL-6 or TNF-α suppressed the effects.

CONCLUSIONS

PEMF attenuates structural and functional progression of OA through inhibition of TNF-α and IL-6 signaling. The protective effects of PEMF on chondrocyte apoptosis and autophagy are regulated by TNF-α and IL-6 signaling.

Cellular stress response to extremely low-frequency electromagnetic fields (ELF-EMF): An explanation for controversial effects of ELF-EMF on apoptosis

Impaired apoptosis is one of the hallmarks of cancer, and almost all of the non‐surgical approaches of eradicating tumour cells somehow promote induction of apoptosis. Indeed, numerous studies have stated that non‐ionizing non‐thermal extremely low‐frequency magnetic fields (ELF‐MF) can modulate the induction of apoptosis in exposed cells; however, much controversy exists in observations. When cells are exposed to ELF‐EMF alone, very low or no statistically significant changes in apoptosis are observed. Contrarily, exposure to ELF‐EMF in the presence of a co‐stressor, including a chemotherapeutic agent or ionizing radiation, can either potentiate or inhibit apoptotic effects of the co‐stressor. In our idea, the main point neglected in interpreting these discrepancies is “the cellular stress responses” of cells following ELF‐EMF exposure and its interplay with apoptosis. The main purpose of the current review was to outline the triangle of ELF‐EMF, the cellular stress response of cells and apoptosis and to interpret and unify discrepancies in results based on it. Therefore, initially, we will describe studies performed on identifying the effect of ELF‐EMF on induction/inhibition of apoptosis and enumerate proposed pathways through which ELF‐EMF exposure may affect apoptosis; then, we will explain cellular stress response and cues for its induction in response to ELF‐EMF exposure; and finally, we will explain why such controversies have been observed by different investigators.

Human tendon-derived cell sheets created by magnetic force-based tissue engineering hold tenogenic and immunomodulatory potential

Cell sheet technology and magnetic based tissue engineering hold the potential to become instrumental in developing magnetically responsive living tissues analogues that can be potentially used both for modeling and therapeutical purposes. Cell sheet constructions more closely recreate physiological niches, through the preservation of contiguous cells and cell-ECM interactions, which assist the cellular guidance in regenerative processes. We herein propose to use magnetically assisted cell sheets (magCSs) constructed with human tendon-derived cells (hTDCs) and magnetic nanoparticles to study inflammation activity upon magCSs exposure to IL-1β, anticipating its added value for tendon disease modeling. Our results show that IL-1β induces an inflammatory profile in magCSs, supporting its in vitro use to enlighten inflammation mediated events in tendon cells. Moreover, the response of magCSs to IL-1β is modulated by pulsed electromagnetic field (PEMF) stimulation, favoring the expression of anti-inflammatory genes, which seems to be associated to MAPK(ERK1/2) pathway. The anti-inflammatory response to PEMF together with the immunomodulatory potential of magCSs opens new perspectives for their applicability on tendon regeneration that goes beyond advanced cell based modeling. STATEMENT OF SIGNIFICANCE: The combination of cell sheets and magnetic-based technologies holds promise as instrumental bio-instructive tools both for tendon disease modelling and for the development of magnetically responsive living tendon substitutes. We have previously shown that remote actuation of a pulsed electromagnetic field (PEMF) modulated the inflammatory response of IL-1β-treated human tendon-derived cell (hTDCs) monolayers. As magnetic cell sheets (magCSs) technologies enable improved cellular organization and matrix deposition, these constructions could better recapitulate tendon niches. In this work, we aimed to apply magCSs technologies to study hTDCs responses in inflammatory environments. Overall results show that PEMF-stimulated-magCSs hold evidence for immunomodulatory properties and to become a living tendon model envisioning tendon regenerative therapies.

Pulsed-electromagnetic-field induced osteoblast differentiation requires activation of genes downstream of adenosine receptors A2A and A3

Pulsed-electromagnetic-field (PEMF) treatment was found to enhance cellular differentiation of the mouse preosteoblast, MC3T3-E1, to a more osteoblastic phenotype. Differentiation genes such as Alp, BSPI, cFos, Ibsp, Osteocalcin, Pthr1 and Runx2 showed increased expression in response to PEMF stimulation. Detailed molecular mechanisms linking PEMF to the activation of these genes are limited. Two adenosine receptors known to be modulated in response to PEMF, Adora2A and Adora3, were functionally impaired by CRISPR-Cas9-mediated gene disruption, and the consequences of which were studied in the context of PEMF-mediated osteoblastic differentiation. Disruption of Adora2A resulted in a delay of Alp mRNA expression, but not alkaline phosphatase protein expression, which was similar to that found in wild type cells. However, Adora3 disruption resulted in significantly reduced responses at both the alkaline phosphatase mRNA and protein levels throughout the PEMF stimulation period. Defects observed in response to PEMF were mirrored using a chemically defined growth and differentiation-inducing media (DM). Moreover, in cells with Adora2A disruption, gene expression profiles showed a blunted response in cFos and Pthr1 to PEMF treatment; whereas cells with Adora3 disruption had mostly blunted responses in AlpI, BSPI, Ibsp, Osteocalcin and Sp7 gene activation. To demonstrate specificity for Adora3 function, the Adora3 open reading frame was inserted into the ROSA26 locus in Adora3 disrupted cells culminating in rescued PEMF responsiveness and thereby eliminating the possibility of off-target effects. These results lead us to propose that there are complementary and parallel positive roles for adenosine receptor A_2A and A₃ in PEMF-mediated osteoblast differentiation.

Effects of modulation on sodium and potassium channel currents by extremely low frequency electromagnetic fields stimulation on hippocampal CA1 pyramidal cells

To investigate the effects of extremely low-frequency electromagnetic fields (ELF-EMFs) stimulation on sodium channel currents (I_Na), transient outward potassium channel currents (I_A) and delayed rectifier potassium channel currents (I_K) on hippocampal CA1 pyramidal neurons of young Sprague-Dawley rats. CA1 pyramidal neurons of rat hippocampal slices were subjected to ELF-EMFs stimulation with different frequencies (15 and 50 Hz), intensities (0.5, 1 and 2 mT) and durations (10, 20 and 30 min). The I_Na, I_A and I_K of neurons were recorded by a whole-cell patch-clamp method. ELF-EMFs stimulation enhanced I_Na densities, and depressed I_A and I_K densities. In detail, I_Na was more sensitive to the variation of intensities and frequencies of ELF-EMFs, whereas I_A and I_K were mainly affected by the variation of the duration of ELF-EMFs. ELF-EMFs stimulation altered activation and deactivation properties of I_Na, I_A and I_K. ELF-EMFs stimulation plays a role as a regulator rather than an inducer for ion channels. It might change the transition probability of ion channel opening or closing, and might also change the structure and function of the ion channel which need to be proved by the further technical method.

Pulsed Electromagnetic Field Stimulation in Osteogenesis and Chondrogenesis: Signaling Pathways and Therapeutic Implications

Mesenchymal stem cells (MSCs) are the main cell players in tissue repair and thanks to their self-renewal and multi-lineage differentiation capabilities, they gained significant attention as cell source for tissue engineering (TE) approaches aimed at restoring bone and cartilage defects. Despite significant progress, their therapeutic application remains debated: the TE construct often fails to completely restore the biomechanical properties of the native tissue, leading to poor clinical outcomes in the long term. Pulsed electromagnetic fields (PEMFs) are currently used as a safe and non-invasive treatment to enhance bone healing and to provide joint protection. PEMFs enhance both osteogenic and chondrogenic differentiation of MSCs. Here, we provide extensive review of the signaling pathways modulated by PEMFs during MSCs osteogenic and chondrogenic differentiation. Particular attention has been given to the PEMF-mediated activation of the adenosine signaling and their regulation of the inflammatory response as key player in TE approaches. Overall, the application of PEMFs in tissue repair is foreseen: (1) in vitro: to improve the functional and mechanical properties of the engineered construct; (2) in vivo: (i) to favor graft integration, (ii) to control the local inflammatory response, and (iii) to foster tissue repair from both implanted and resident MSCs cells.

Pulsed electromagnetic fields improve the healing process of Achilles tendinopathy: a pilot study in a rat model

Aims

In the context of tendon degenerative disorders, the need for innovative conservative treatments that can improve the intrinsic healing potential of tendon tissue is progressively increasing. In this study, the role of pulsed electromagnetic fields (PEMFs) in improving the tendon healing process was evaluated in a rat model of collagenase-induced Achilles tendinopathy.

Methods

A total of 68 Sprague Dawley rats received a single injection of type I collagenase in Achilles tendons to induce the tendinopathy and then were daily exposed to PEMFs (1.5 mT and 75 Hz) for up to 14 days - starting 1, 7, or 15 days after the injection - to identify the best treatment option with respect to the phase of the disease. Then, 7 and 14 days of PEMF exposure were compared to identify the most effective protocol.

Results

The daily exposure to PEMFs generally provided an improvement in the fibre organization, a decrease in cell density, vascularity, and fat deposition, and a restoration of the physiological cell morphology compared to untreated tendons. These improvements were more evident when the tendons were exposed to PEMFs during the mid-acute phase of the pathology (7 days after induction) rather than during the early (1 day after induction) or the late acute phase (15 days after induction). Moreover, the exposure to PEMFs for 14 days during the mid-acute phase was more effective than for 7 days.

Conclusion

PEMFs exerted a positive role in the tendon healing process, thus representing a promising conservative treatment for tendinopathy, although further investigations regarding the clinical evaluation are needed.

Cite this article: Bone Joint Res 2020;9(9):613–622.

A2A adenosine receptors are involved in the reparative response of tendon cells to pulsed electromagnetic fields

Tendinopathy is a degenerative disease in which inflammatory mediators have been found to be sometimes present. The interaction between inflammation and matrix remodeling in human tendon cells (TCs) is supported by the secretion of cytokines such as IL-1β, IL-6 and IL-33. In this context, it has been demonstrated that pulsed electromagnetic fields (PEMFs) were able to reduce inflammation and promote tendon marker synthesis. The aim of this study was to evaluate the anabolic and anti-inflammatory PEMF-mediated response on TCs in an in vitro model of inflammation. Moreover, since PEMFs enhance the anti-inflammatory efficacy of adenosine through the adenosine receptors (ARs), the study also focused on the role of A_2AARs. Human TCs were exposed to PEMFs for 48 hours. After stimulation, A_2AAR saturation binding experiments were performed. Along with 48 hours PEMF stimulation, TCs were treated with IL-1β and A_2AAR agonist CGS-21680. IL-1Ra, IL-6, IL-8, IL-10, IL-33, VEGF, TGF-β1, PGE₂ release and SCX, COL1A1, COL3A1, ADORA2A expression were quantified. PEMFs exerted A_2AAR modulation on TCs and promoted COL3A1 upregulation and IL-33 secretion. In presence of IL-1β, TCs showed an upregulation of ADORA2A, SCX and COL3A1 expression and an increase of IL-6, IL-8, PGE₂ and VEGF secretion. After PEMF and IL-1β exposure, IL-33 was upregulated, whereas IL-6, PGE₂ and ADORA2A were downregulated. These findings demonstrated that A_2AARs have a role in the promotion of the TC anabolic/reparative response to PEMFs and to IL-1β.

Effects of Pulsed Electromagnetic Field Therapy on Pain, Stiffness, Physical Function, and Quality of Life in Patients With Osteoarthritis: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials

OBJECTIVE

Pulsed electromagnetic field (PEMF) therapy is a potentially useful treatment for osteoarthritis (OA), but its effectiveness is still controversial. This study aimed to examine the effects of PEMF therapy and PEMF parameters on symptoms and quality of life (QOL) in patients with OA.

METHODS

Cochrane Central Register of Controlled Trials, PubMed, CINAHL, EMBASE, PEDro, clinical trial registers, and reference lists were searched until April 2019. This study examined randomized, placebo-controlled trials, patients with OA, symptom and/or QOL related outcomes, and articles published in English. Two authors extracted data and completed quality assessment.

RESULTS

Sixteen studies were included in our systematic review, while 15 studies with complete data were included in the meta-analysis. Our primary outcome was the standardized mean difference, which was equal to the treatment effect in the PEMF group minus the treatment effect in the placebo group divided by the pooled standard deviation. For pain, the standardized mean difference was 1.06 (95% CI = 0.61 to 1.51), for stiffness 0.37 (95% CI = 0.07 to 0.67), for function 0.46 (95% CI = 0.14 to 0.78), and for QOL 1.49 (95% CI = -0.06 to 3.04). PEMF parameters did not influence symptoms.

CONCLUSIONS

Compared with placebo, there was a beneficial effect of PEMF therapy on pain, stiffness, and physical function in patients with OA. Duration of treatment may not be a critical factor in pain management. Further studies are required to confirm the effects of PEMF therapy on QOL.

IMPACT

Our study suggests that PEMF therapy has clinically significant effects on pain in patients with OA. The current evidence was limited to the short-term effects of PEMF therapy.

Pulsed Electromagnetic Field Inhibits Synovitis via Enhancing the Efferocytosis of Macrophages

Synovitis plays an important role in the pathogenesis of arthritis, which is closely related to the joint swell and pain of patients. The purpose of this study was to investigate the anti-inflammatory effects of pulsed electromagnetic fields (PEMF) on synovitis and its underlying mechanisms. Destabilization of the medial meniscus (DMM) model and air pouch inflammation model were established to induce synovitis in C57BL/6 mice. The mice were then treated by PEMF (pulse waveform, 1.5 mT, 75 Hz, 10% duty cycle). The synovitis scores as well as the levels of IL-1β and TNF-α suggested that PEMF reduced the severity of synovitis in vivo. Moreover, the proportion of neutrophils in the synovial-like layer was decreased, while the proportion of macrophages increased after PEMF treatment. In addition, the phagocytosis of apoptotic neutrophils by macrophages (efferocytosis) was enhanced by PEMF. Furthermore, the data from western blot assay showed that the phosphorylation of P38 was inhibited by PEMF. In conclusion, our current data show that PEMF noninvasively exhibits the anti-inflammatory effect on synovitis via upregulation of the efferocytosis in macrophages, which may be involved in the phosphorylation of P38.

Specific low-frequency electromagnetic fields induce expression of active KDM6B associated with functional changes in U937 cells

In this study, we investigated the effects of specific low-frequency electromagnetic field sequences on U937 cells, an in vitro model of human monocyte/macrophage differentiation. U937 cells were exposed to electromagnetic stimulation by means of the SynthéXer system using two similar sequences, XR-BC31 and XR-BC31/F. Each sequence was a time series of 29 wave segments, equal to a total duration of 77 min. Here, we report that exposure (4 d, once a day) of U937 cells to the XR-BC31 setting, but not to the XR-BC31/F, resulted in increased expression of the histone demethylase KDM6B along with a global reduction in histone H3 lysine 27 tri-methylation (H3K27me3). Furthermore, exposure to the XR-BC31 sequence induced differentiation of U937 cells towards a macrophage-like phenotype displaying a KDM6B dependent increase in expression and secretion of the anti-inflammatory interleukins (ILs), IL-10 and IL-4. Importantly, all the observed changes were highly dependent on the nature of the sequence. Our results open a new way of interpretation for the effects of low-frequency electromagnetic fields observed in vivo. Indeed, it is conceivable that a specific low-frequency electromagnetic fields treatment may cause the reprogramming of H3K27me3 and cell differentiation.

Bone Morphogenetic Protein-2 Signaling in the Osteogenic Differentiation of Human Bone Marrow Mesenchymal Stem Cells Induced by Pulsed Electromagnetic Fields

Pulsed electromagnetic fields (PEMFs) are clinically used with beneficial effects in the treatment of bone fracture healing. This is due to PEMF ability to favor the osteogenic differentiation of mesenchymal stem cells (MSCs). Previous studies suggest that PEMFs enhance the osteogenic activity of bone morphogenetic protein-2 (BMP2) which is used in various therapeutic interventions. This study investigated the molecular events associated to the synergistic activity of PEMFs and BMP2 on osteogenic differentiation. To this aim, human MSCs (hMSCs) were exposed to PEMFs (75 Hz, 1.5 mT) in combination with BMP2, upon detection of the minimal dose able to induce differentiation. Changes in the expression of BMP signaling pathway genes including receptors and ligands, as well as in the phosphorylation of BMP downstream signaling proteins, such as SMAD1/5/8 and MAPK, were analyzed. Results showed the synergistic activity of PEMFs and BMP2 on osteogenic differentiation transcription factors and markers. The PEMF effects were associated to the increase in BMP2, BMP6, and BMP type I receptor gene expression, as well as SMAD1/5/8 and p38 MAPK activation. These results increase knowledge concerning the molecular events involved in PEMF stimulation showing that PEMFs favor hMSCs osteogenic differentiation by the modulation of BMP signaling components.

High Human Papillomavirus DNA loads in Inflammatory Middle Ear Diseases

Background. Previous studies reported human papillomaviruses (HPVs) in middle ear tumors, whereas these viruses have been poorly investigated in chronic inflammatory middle ear diseases. We investigated HPVs in non-tumor middle ear diseases, including chronic otitis media (COM). Methods. COM specimens (n = 52), including chronic suppurative otitis media (CSOM) (n =38) and cholesteatoma (COMC) (n = 14), as well as normal middle ear (NME) specimens (n = 56) were analyzed. HPV sequences and DNA loads were analyzed by quantitative-PCR. HPV genotyping was performed by direct sequencing. Results. HPV DNA was detected in 23% (12/52) of COM and in 30.4% (17/56) of NME (p > 0.05). Specifically, HPV DNA sequences were found in 26.3% (10/38) of CSOM and in 14.3% (2/14) of COMC (p > 0.05). Interestingly, the HPV DNA load was higher in COMC (mean 7.47 copy/cell) than in CSOM (mean 1.02 copy/cell) and NME (mean 1.18 copy/cell) (P = 0.03 and P = 0.017 versus CSOM and NME, respectively). HPV16 and HPV18 were the main genotypes detected in COMC, CSOM and NME. Conclusions. These data suggest that HPV may infect the middle ear mucosa, whereas HPV-positive COMCs are associated with higher viral DNA loads as compared to NME.

Pulsed electromagnetic fields potentiate the paracrine function of mesenchymal stem cells for cartilage regeneration

Background

The mesenchymal stem cell (MSC) secretome, via the combined actions of its plethora of biologically active factors, is capable of orchestrating the regenerative responses of numerous tissues by both eliciting and amplifying biological responses within recipient cells. MSCs are “environmentally responsive” to local micro-environmental cues and biophysical perturbations, influencing their differentiation as well as secretion of bioactive factors. We have previously shown that exposures of MSCs to pulsed electromagnetic fields (PEMFs) enhanced MSC chondrogenesis. Here, we investigate the influence of PEMF exposure over the paracrine activity of MSCs and its significance to cartilage regeneration.

Methods

Conditioned medium (CM) was generated from MSCs subjected to either 3D or 2D culturing platforms, with or without PEMF exposure. The paracrine effects of CM over chondrocytes and MSC chondrogenesis, migration and proliferation, as well as the inflammatory status and induced apoptosis in chondrocytes and MSCs was assessed.

Results

We show that benefits of magnetic field stimulation over MSC-derived chondrogenesis can be partly ascribed to its ability to modulate the MSC secretome. MSCs cultured on either 2D or 3D platforms displayed distinct magnetic sensitivities, whereby MSCs grown in 2D or 3D platforms responded most favorably to PEMF exposure at 2 mT and 3 mT amplitudes, respectively. Ten minutes of PEMF exposure was sufficient to substantially augment the chondrogenic potential of MSC-derived CM generated from either platform. Furthermore, PEMF-induced CM was capable of enhancing the migration of chondrocytes and MSCs as well as mitigating cellular inflammation and apoptosis.

Conclusions

The findings reported here demonstrate that PEMF stimulation is capable of modulating the paracrine function of MSCs for the enhancement and re-establishment of cartilage regeneration in states of cellular stress. The PEMF-induced modulation of the MSC-derived paracrine function for directed biological responses in recipient cells or tissues has broad clinical and practical ramifications with high translational value across numerous clinical applications.

Electronic supplementary material

The online version of this article (10.1186/s13287-020-1566-5) contains supplementary material, which is available to authorized users.

Effects of Various Densities of 50 Hz Electromagnetic Field on Serum IL-9, IL-10, and TNF-α Levels

Background:

Extremely low-frequency electromagnetic fields (ELF-EMFs) are abundantly produced in modern societies. In recent years, interest in the possible effects of ELF-EMFs on the immune system has progressively increased.

Objective:

To examine the effects of ELF-EMFs with magnetic flux densities of 1, 100, 500, and 2000 µT on the serum levels of interleukin (IL)-9, IL-10, and tumor necrosis factor-alpha (TNF-α).

Methods:

80 adult male rats were exposed to ELF-EMFs at a frequency of 50 Hz for 2 h/day for 60 days. The serum cytokines were measured at two phases of pre- and post-stimulation of the immune system by human serum albumin (HSA).

Results:

Serum levels of IL-9 and TNF-α, as pro-inflammatory cytokines, were decreased due to 50 Hz EMFs exposure compared with the controls in the pre- and post-stimulation phases. On the contrary, exposures to 1 and 100 µT 50 Hz EMFs increased the levels of antiinflammatory cytokine, and IL-10 only in the pre-stimulation phase. In the post-stimulation phase, the mean level of serum IL-10 was not changed in the experimental groups.

Conclusion:

The magnetic flux densities of 1 and 100 µT 50 Hz EMFs had more immunological effects than EMFs with higher densities. Exposure to 50 Hz EMFs may activate anti-inflammatory effects in rats, by down-modulation of pro-inflammatory cytokines (IL-9 and TNF-α) and induction of the anti-inflammatory cytokine (IL-10).

Pulsed electromagnetic field and relief of hypoxia-induced neuronal cell death: The signaling pathway

Low-energy low-frequency pulsed electromagnetic fields (PEMFs) exert several protective effects, such as the regulation of kinases, transcription factors as well as cell viability in both central and peripheral biological systems. However, it is not clear on which bases they affect neuroprotection and the mechanism responsible is yet unknown. In this study, we have characterized in nerve growth factor-differentiated pheochromocytoma PC12 cells injured with hypoxia: (i) the effects of PEMF exposure on cell vitality; (ii) the protective pathways activated by PEMFs to relief neuronal cell death, including adenylyl cyclase, phospholipase C, protein kinase C epsilon and delta, p38, ERK1/2, JNK1/2 mitogen-activated protein kinases, Akt and caspase-3; (iii) the regulation by PEMFs of prosurvival heat-shock proteins of 70 (HSP70), cAMP response element-binding protein (CREB), brain-derived neurotrophic factor (BDNF), and Bcl-2 family proteins. The results obtained in this study show a protective effect of PEMFs that are able to reduce neuronal cell death induced by hypoxia by modulating p38, HSP70, CREB, BDNF, and Bcl-2 family proteins. Specifically, we found a rapid activation (30 min) of p38 kinase cascade, which in turns enrolles HSP70 survival chaperone molecule, resulting in a significant CREB phosphorylation increase (24 hr). In this cascade, later (48 hr), BDNF and the antiapoptotic pathway regulated by the Bcl-2 family of proteins are recruited by PEMFs to enhance neuronal survival. This study paves the way to elucidate the mechanisms triggered by PEMFs to act as a new neuroprotective approach to treat cerebral ischemia by reducing neuronal cell death.

Signaling pathways involved in anti-inflammatory effects of Pulsed Electromagnetic Field in microglial cells

Literature studies suggest important protective effects of low-frequency, low-energy pulsed electromagnetic fields (PEMFs) on inflammatory pathways affecting joint and cerebral diseases. However, it is not clear on which bases they affect neuroprotection and the mechanism responsible is yet unknown. Therefore the aim of this study was to identify the molecular targets of PEMFs anti-neuroinflammatory action. The effects of PEMF exposure in cytokine production by lipopolysaccharide (LPS)-activated N9 microglial cells as well as the pathways involved, including adenylyl cyclase (AC), phospholipase C (PLC), protein kinase C epsilon (PKC-ε) and delta (PKC-δ), p38, ERK1/2, JNK1/2 mitogen activated protein kinases (MAPK), Akt and caspase 1, were investigated. In addition, the ability of PEMFs to modulate ROS generation, cell invasion and phagocytosis, was addressed. PEMFs reduced the LPS-increased production of TNF-α and IL-1β in N9 cells, through a pathway involving JNK1/2. Furthermore, they decreased the LPS-induced release of IL-6, by a mechanism not dependent on AC, PLC, PKC-ε, PKC-δ, p38, ERK1/2, JNK1/2, Akt and caspase 1. Importantly, a significant effect of PEMFs in the reduction of crucial cell functions specific of microglia like ROS generation, cell invasion and phagocytosis was found. PEMFs inhibit neuroinflammation in N9 cells through a mechanism involving, at least in part, the activation of JNK MAPK signalling pathway and may be relevant to treat a variety of diseases characterized by neuroinflammation.

Effects of electromagnetic fields on osteoarthritis

Osteoarthritis (OA), characterized by joint malfunction and chronic disability, is the most common form of arthritis. The pathogenesis of OA is unclear, yet studies have shown that it is due to an imbalance between the synthesis and decomposition of chondrocytes, cell matrices and subchondral bone, which leads to the degeneration of articular cartilage. Currently, there are many therapies that can be used to treat OA, including the use of pulsed electromagnetic fields (PEMFs). PEMFs stimulate proliferation of chondrocytes and exert a protective effect on the catabolic environment. Furthermore, this technique is beneficial for subchondral trabecular bone microarchitecture and the prevention of subchondral bone loss, ultimately blocking the progression of OA. However, it is still unknown whether PEMFs could be used to treat OA in the clinic. Furthermore, the deeper signaling pathways underlying the mechanism by which PEMFs influence OA remain unclear.

Global Responses of Il-1β-Primed 3D Tendon Constructs to Treatment with Pulsed Electromagnetic Fields

Tendinopathy is accompanied by a cascade of inflammatory events promoting tendon degeneration. Among various cytokines, interleukin-1β plays a central role in driving catabolic processes, ultimately resulting in the activation of matrix metalloproteinases and a diminished collagen synthesis, both of which promote tendon extracellular matrix degradation. Pulsed electromagnetic field (PEMF) therapy is often used for pain management, osteoarthritis, and delayed wound healing. In vitro PEMF treatment of tendon-derived cells was shown to modulate pro-inflammatory cytokines, potentially limiting their catabolic effects. However, our understanding of the underlying cellular and molecular mechanisms remains limited. We therefore investigated the transcriptome-wide responses of Il-1β-primed rat Achilles tendon cell-derived 3D tendon-like constructs to high-energy PEMF treatment. RNASeq analysis and gene ontology assignment revealed various biological processes to be affected by PEMF, including extracellular matrix remodeling and negative regulation of apoptosis. Further, we show that members of the cytoprotective Il-6/gp130 family and the Il-1β decoy receptor Il1r2 are positively regulated upon PEMF exposure. In conclusion, our results provide fundamental mechanistic insight into the cellular and molecular mode of action of PEMF on tendon cells and can help to optimize treatment protocols for the non-invasive therapy of tendinopathies.

Targeting Mesenchymal Stromal Cells/Pericytes (MSCs) With Pulsed Electromagnetic Field (PEMF) Has the Potential to Treat Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation of synovium (synovitis), with inflammatory/immune cells and resident fibroblast-like synoviocytes (FLS) acting as major players in the pathogenesis of this disease. The resulting inflammatory response poses considerable risks as loss of bone and cartilage progresses, destroying the joint surface, causing joint damage, joint failure, articular dysfunction, and pre-mature death if left untreated. At the cellular level, early changes in RA synovium include inflammatory cell infiltration, synovial hyperplasia, and stimulation of angiogenesis to the site of injury. Different angiogenic factors promote this disease, making the role of anti-angiogenic therapy a focus of RA treatment. To control angiogenesis, mesenchymal stromal cells/pericytes (MSCs) in synovial tissue play a vital role in tissue repair. While recent evidence reports that MSCs found in joint tissues can differentiate to repair damaged tissue, this repair function can be repressed by the inflammatory milieu. Extremely-low frequency pulsed electromagnetic field (PEMF), a biophysical form of stimulation, has an anti-inflammatory effect by causing differentiation of MSCs. PEMF has also been reported to increase the functional activity of MSCs to improve differentiation to chondrocytes and osteocytes. Moreover, PEMF has been demonstrated to accelerate cell differentiation, increase deposition of collagen, and potentially return vascular dysfunction back to homeostasis. The aim of this report is to review the effects of PEMF on MSC modulation of cytokines, growth factors, and angiogenesis, and describe its effect on MSC regeneration of synovial tissue to further understand its potential role in the treatment of RA.

Pulsed electromagnetic fields: promising treatment for osteoporosis

Osteoporosis (OP) is considered to be a well-defined disease which results in high morbidity and mortality. In patients diagnosed with OP, low bone mass and fragile bone strength have been demonstrated to significantly increase risk of fragility fractures. To date, various anabolic and antiresorptive therapies have been applied to maintain healthy bone mass and strength. Pulsed electromagnetic fields (PEMFs) are employed to treat patients suffering from delayed fracture healing and nonunions. Although PEMFs stimulate osteoblastogenesis, suppress osteoclastogenesis, and influence the activity of bone marrow mesenchymal stem cells (BMSCs) and osteocytes, ultimately leading to retention of bone mass and strength. However, whether PEMFs could be taken into clinical use to treat OP is still unknown. Furthermore, the deeper signaling pathways underlying the way in which PEMFs influence OP remain unclear.

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.

Low‑frequency pulsed electromagnetic field promotes functional recovery, reduces inflammation and oxidative stress, and enhances HSP70 expression following spinal cord injury

Low-frequency pulsed electromagnetic fields (LPEMFs) have been reported to be protective for multiple diseases. However, whether the administration of LPEMFs inhibits inflammation and oxidative stress following spinal cord injury requires further investigation. In the current study, a contusion spinal cord injury model was used and LPEMFs administration was applied to investigate the molecular changes, including inflammation, oxidative stress and heat shock protein 70 (HSP70) levels. The results revealed that LPEMFs significantly promoted functional recovery following spinal cord injury, as demonstrated by an increased Basso, Beattie and Bresnahan score. The results demonstrated that LPEMFs decreased the expression of inflammatory factors, including tumor necrosis factor-α, interleukin-1β and nuclear factor-κB. Additionally, LPEMFs exposure reduced the levels of inducible nitric oxide synthase and reactive oxygen species, and upregulated the expression of catalase and superoxide dismutase. Furthermore, treatment with LPEMFs significantly enhanced the expression of HSP70 in spinal cord-injured rats. Overall, the present study revealed that LPEMFs promote functional recovery following spinal cord injury, potentially by modulating inflammation, oxidative stress and HSP70.

Biological effects of non-ionizing electromagnetic fields: Two sides of a coin

Controversial, sensational and often contradictory scientific reports have triggered active debates over the biological effects of electromagnetic fields (EMFs) in literature and mass media the last few decades. This could lead to confusion and distraction, subsequently hampering the development of a univocal conclusion on the real hazards caused by EMFs on humans. For example, there are lots of publications indicating that EMF can induce apoptosis and DNA strand-breaks in cells. On the other hand, these effects could rather be beneficial, in that they could be effectively harnessed for treatment of various disorders, including cancer. This review discusses and analyzes the results of various in vitro, in vivo and epidemiological studies on the effects of non-ionizing EMFs on cells and organs, including the consequences of exposure to the low and high frequencies EM spectrum. Emphasis is laid on the analysis of recent data on the role of EMF in the induction of oxidative stress and DNA damage. Additionally, the impact of EMF on the reproductive system has been discussed, as well as the relationship between EM radiation and blood cancer. Apart from adverse effects, the therapeutic potential of EMFs for clinical use in different pathologies is also highlighted.

Short Exposures to an Extremely Low-Frequency Magnetic Field (ELF MF) Enhance Protein but not mRNA Alkaline Phosphatase Expression in Human Osteosarcoma Cells

Background

Among electromagnetic fields treatments used in orthopedics, extremely low-frequency magnetic fields (ELF MF) need more detailed information about the molecular mechanisms of their effects and exposure conditions.

Objective

Evaluation of the effects of an ELF MF exposure system, recently introduced among current clinical treatments for fracture healing and other bone diseases, on Alkaline Phosphatase (ALP) activity and expression in a human osteosarcoma cell line (SaOS-2), as marker typically associated to osteogenesis and bone tissue regeneration.

Method

Cells were exposed to the ELF MF physical stimulus (75 Hz, 1.5 mT) for 1h. Cell viability, enzymatic activity, protein and mRNA expression of alkaline phosphatase were then measured at different times after exposure (0, 4 and 24 h).

Results

Data demonstrate that this signal is active on an osteogenic process already one hour after exposure. Treatment was, in fact, capable, even after an exposure shorter than those commonly used in clinical applications, to significantly up-regulate alkaline phosphatase enzymatic activity. This regulation is produced essentially through an increase of ALP protein level, without changes of its mRNA concentration, while assessed magnetic field did not affect cell growth and viability and did not produce temperature variations.

Conclusion

Tested low-frequency magnetic field affects cellular ALP expression with a posttranslational mechanism, without the involvement of regulations at gene transcription and mRNA level. This molecular effect is likely produced even within treated tissues during therapies with this signal and may be implicated in the induction of observed effects in treated patients.

Adenosine metabolism, immunity and joint health

The purine nucleoside adenosine is a present in most body fluids where it regulates a wide variety of physiologic and pharmacologic processes. Adenosine mediates its effects through activating 4 G protein-coupled receptors expressed on the cell membrane: A1, A2A, A2B, and A3. The adenosine receptors are widely distributed in the body, and tissues with high expression include immune tissues, cartilage, bone, heart, and brain. Here we review the source and metabolism of adenosine and the role of adenosine in regulating immunity and cartilage biology.

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.

Biophysical stimulation improves clinical results of matrix-assisted autologous chondrocyte implantation in the treatment of chondral lesions of the knee

PURPOSE

The purpose of the present study was to evaluate the effects of pulsed electromagnetic fields (PEMFs) on clinical outcome in patients who underwent arthroscopic matrix-assisted autologous chondrocyte implantation (MACI) for chondral lesions of the knee.

METHODS

Thirty patients affected by grade III and IV International Cartilage Repair Society chondral lesions of the knee underwent MACI. After surgery, patients were randomly assigned to either experimental group (PEMFs 4 h per day for 60 days) or control group . Clinical outcome was evaluated through International Knee Documentation Committee (IKDC) subjective knee evaluation form, Visual Analog Scale, Short Form-36 (SF-36) and EuroQoL before surgery and 1, 2, 6, and 60 months postoperative.

RESULTS

Mean size of chondral lesion was 2.4 ± 0.6 cm² in the PEMFs group and 2.5 ± 0.5 cm² in the control one. No differences were found between groups at baseline. IKDC score increased in both groups till 6 months, but afterward improvement was observed only in the experimental group with a significant difference between groups at 60 months (p = 0.001). A significant difference between groups was recorded at 60 months for SF-36 (p = 0.006) and EuroQol (p = 0.020). A significant pain reduction was observed in the experimental group at 1-, 2- and 60-month follow-up.

CONCLUSION

Biophysical stimulation with PEMFs improves clinical outcome after arthroscopic MACI for chondral lesions of the knee in the short- and long-term follow-up. Biophysical stimulation should be considered as an effective tool in order to ameliorate clinical results of regenerative medicine. The use of PEMFs represents an innovative therapeutic approach for the survival of cartilage-engineered constructs and consequently the success of orthopaedic surgery.

LEVEL OF EVIDENCE

II.

The triune of intestinal microbiome, genetics and inflammatory status and its impact on the healing of lower gastrointestinal anastomoses

Gastrointestinal resections are a common operation and most involve an anastomosis to rejoin the ends of the remaining bowel to restore gastrointestinal (GIT) continuity. While most joins heal uneventfully, in up to 26% of patients healing fails and an anastomotic leak (AL) develops. Despite advances in surgical technology and techniques, the rate of anastomotic leaks has not decreased over the last few decades raising the possibility that perhaps we do not yet fully understand the phenomenon of AL and are thus ill-equipped to prevent it. As in all complex conditions, it is necessary to isolate each different aspect of disease for interrogation of its specific role, but, as we hope to demonstrate in this article, it is a dangerous oversimplification to consider any single aspect as the full answer to the problem. Instead, consideration of important individual observations in parallel could illuminate the way forward towards a possibly simple solution amidst the complexity. This article details three aspects that we believe intertwine, and therefore should be considered together in wound healing within the GIT during postsurgical recovery: the microbiome, the host genetic make-up and their relationship to the perioperative inflammatory status. Each of these, alone or in combination, has been linked with various states of health and disease, and in combining these three aspects in the case of postoperative recovery from bowel resection, we may be nearer an answer to preventing anastomotic leaks than might have been thought just a few years ago.

Immune-Modulating Perspectives for Low Frequency Electromagnetic Fields in Innate Immunity

In recent years, the effects of electromagnetic fields (EMFs) on the immune system have received a considerable interest, not only to investigate possible negative health impact but also to explore the possibility to favorably modulate immune responses. To generate beneficial responses, the immune system should eradicate pathogens while “respecting” the organism and tolerating irrelevant antigens. According to the current view, damage-associated molecules released by infected or injured cells, or secreted by innate immune cells generate danger signals activating an immune response. These signals are also relevant to the subsequent activation of homeostatic mechanisms that control the immune response in pro- or anti-inflammatory reactions, a feature that allows modulation by therapeutic treatments. In the present review, we describe and discuss the effects of extremely low frequency (ELF)-EMF and pulsed EMF on cell signals and factors relevant to the activation of danger signals and innate immunity cells. By discussing the EMF modulating effects on cell functions, we envisage the use of EMF as a therapeutic agent to regulate immune responses associated with wound healing.

Transcranial magnetic stimulation as an antioxidant

In the last decades, different transcranial magnetic stimulation protocols have been developed as a therapeutic tool against neurodegenerative and psychiatric diseases, although the biochemical, molecular and cellular mechanisms underlying these effects are not well known. Recent data show that those magnetic stimulation protocols showing beneficial effects could trigger an anti-oxidant action that would favour, at least partially, their therapeutic effect. We have aimed to review the molecular effects related to oxidative damage induced by this therapeutic strategy, as well as from them addressing a broader definition of the anti-oxidant concept.

Magnetic Fields and Reactive Oxygen Species

Reactive oxygen species (ROS) ubiquitously exist in mammalian cells to participate in various cellular signaling pathways. The intracellular ROS levels are dependent on the dynamic balance between ROS generation and elimination. In this review, we summarize reported studies about the influences of magnetic fields (MFs) on ROS levels. Although in most cases, MFs increased ROS levels in human, mouse, rat cells, and tissues, there are also studies showing that ROS levels were decreased or not affected by MFs. Multiple factors could cause these discrepancies, including but not limited to MF type/intensity/frequency, exposure time and assay time-point, as well as different biological samples examined. It will be necessary to investigate the influences of different MFs on ROS in various biological samples systematically and mechanistically, which will be helpful for people to get a more complete understanding about MF-induced biological effects. In addition, reviewing the roles of MFs in ROS modulation may open up new scenarios of MF application, which could be further and more widely adopted into clinical applications, particularly in diseases that ROS have documented pathophysiological roles.

Purinergic Signalling: Therapeutic Developments

Purinergic signalling, i.e., the role of nucleotides as extracellular signalling molecules, was proposed in 1972. However, this concept was not well accepted until the early 1990's when receptor subtypes for purines and pyrimidines were cloned and characterised, which includes four subtypes of the P1 (adenosine) receptor, seven subtypes of P2X ion channel receptors and 8 subtypes of the P2Y G protein-coupled receptor. Early studies were largely concerned with the physiology, pharmacology and biochemistry of purinergic signalling. More recently, the focus has been on the pathophysiology and therapeutic potential. There was early recognition of the use of P1 receptor agonists for the treatment of supraventricular tachycardia and A2A receptor antagonists are promising for the treatment of Parkinson's disease. Clopidogrel, a P2Y12 antagonist, is widely used for the treatment of thrombosis and stroke, blocking P2Y12 receptor-mediated platelet aggregation. Diquafosol, a long acting P2Y2 receptor agonist, is being used for the treatment of dry eye. P2X3 receptor antagonists have been developed that are orally bioavailable and stable in vivo and are currently in clinical trials for the treatment of chronic cough, bladder incontinence, visceral pain and hypertension. Antagonists to P2X7 receptors are being investigated for the treatment of inflammatory disorders, including neurodegenerative diseases. Other investigations are in progress for the use of purinergic agents for the treatment of osteoporosis, myocardial infarction, irritable bowel syndrome, epilepsy, atherosclerosis, depression, autism, diabetes, and cancer.

Effect of electromagnetic fields on human osteoarthritic and non-osteoarthritic chondrocytes

BACKGROUND

Studies of the effects of electromagnetic fields (EMFs) on cartilaginous cells show a broad range of outcomes. However EMFs are not yet clinically applied as standard treatment of osteoarthritis, as EMF effects are showing varying outcomes in the literature. The aim of this study was to examine effects of EMFs (5 mT or 8 mT) on osteoarthritic (OA) and non-OA chondrocytes in order to investigate whether EMF effects are related to chondrocyte and EMF quality.

METHODS

Pellets of human OA and non-OA chondrocytes were exposed to a sinusoidal 15 Hz EMF produced by a solenoid. Control groups were cultivated without EMF under standard conditions for 7 days. Cultures were examined by staining, immunohistochemistry and quantitative real-time PCR for RNA corresponding to cartilage specific proteins (COL2A1, ACAN, SOX9).

RESULTS

OA chondrocytes increased the expression of COL2A1 and ACAN under 5 mT EMF compared to control. In contrast no changes in gene expression were observed in non-OA chondrocytes. OA and non-OA chondrocytes showed no significant changes in gene expression under 8 mT EMF.

CONCLUSION

A 5 mT EMF increased the expression of cartilage specific genes in OA chondrocytes whereas in non-OA chondrocytes no changes in gene expression were observed. An 8 mT EMF however showed no effect altogether. This suggests that EMF effects are related to EMF but also to chondrocyte quality. Further studies about the clinical relevance of this effect are necessary.

Notch pathway is active during osteogenic differentiation of human bone marrow mesenchymal stem cells induced by pulsed electromagnetic fields

Pulsed electromagnetic fields (PEMFs) have been used to treat bone diseases, particularly nonunion healing. Although it is known that PEMFs promote the osteogenic differentiation of human mesenchymal stem cells (hMSCs), to date PEMF molecular mechanisms remain not clearly elucidated. The Notch signalling is a highly conserved pathway that regulates cell fate decisions and skeletal development. The aim of this study was to investigate if the known PEMF-induced osteogenic effects may involve the modulation of the Notch pathway. To this purpose, during in vitro osteogenic differentiation of bone marrow hMSCs in the absence and in the presence of PEMFs, osteogenic markers (alkaline phosphatase activity, osteocalcin and matrix mineralization), the messenger ribonucleic acid expression of osteogenic transcription factors (Runx2, Dlx5, Osterix) as well as of Notch receptors (Notch1-4), their ligands (Jagged1, Dll1 and Dll4) and nuclear target genes (Hes1, Hes5, Hey1, Hey2) were investigated. PEMFs stimulated all osteogenic markers and increased the expression of Notch4, Dll4, Hey1, Hes1 and Hes5 in osteogenic medium compared to control. In the presence of DAPT and SAHM1, used as Notch pathway inhibitors, the expression of the osteogenic markers, including Runx2, Dlx5, Osterix, as well as Hes1 and Hes5 were significantly inhibited, both in unexposed and PEMF-exposed hMSCs. These results suggest that activation of Notch pathway is required for PEMFs-stimulated osteogenic differentiation. These new findings may be useful to improve autologous cell-based regeneration of bone defects in orthopaedics.