The effect of pulsed electromagnetic field exposure on osteoinduction of human mesenchymal stem cells cultured on nano-TiO2 surfaces

Mathematical models on bone cell homeostasis and kinetics in the presence of electric fields: a review

The role of bioelectricity in regulating various physiological processes has attracted increasing scientific interest in implementing exogenous electrical stimulations as a therapeutic approach. In particular, electrical stimuli are used clinically in pre-/post-surgery patient care for the musculoskeletal tissues. The reported potential of electric fields (EF) to regulate bone cell homeostasis and kineticsin vitrohas further provoked more studies in this field of research. Various customised apparatuses have been developed, and a range of parameters for the applied EFs have been investigatedin vitrowith bone cells or mesenchymal stem cells. Additionally, biomaterials with conductive or piezo-electric properties have been designed to complement the enhancing effects of the EF on bone regeneration. Despite much research, there remained a significant gap in knowledge due to the diverse range of EF parameters available. Mathematical models are built to facilitate further understanding and zero in on an effective range of EF parametersin silico. However, the diverse range of EF parameters, experimental conditions, and reported analytical output of different works of literature were reported to possess significant variance, making it challenging to accurately model the fieldin silico. This review categorises the existing experimental approaches and the parameters used to distinguish the potential variables that apply to mathematical modelling. Furthermore, we will discuss existing modelling approaches and models available in the literature. With this, we will concisely highlight the need to categorise EF parameters, osteogenic differentiation initiators and research output.

The Future of Bone Repair: Emerging Technologies and Biomaterials in Bone Regeneration

Bone defects and fractures present significant clinical challenges, particularly in orthopedic and maxillofacial applications. While minor bone defects may be capable of healing naturally, those of a critical size necessitate intervention through the use of implants or grafts. The utilization of traditional methodologies, encompassing autografts and allografts, is constrained by several factors. These include the potential for donor site morbidity, the restricted availability of suitable donors, and the possibility of immune rejection. This has prompted extensive research in the field of bone tissue engineering to develop advanced synthetic and bio-derived materials that can support bone regeneration. The optimal bone substitute must achieve a balance between biocompatibility, bioresorbability, osteoconductivity, and osteoinductivity while simultaneously providing mechanical support during the healing process. Recent innovations include the utilization of three-dimensional printing, nanotechnology, and bioactive coatings to create scaffolds that mimic the structure of natural bone and enhance cell proliferation and differentiation. Notwithstanding the advancements above, challenges remain in optimizing the controlled release of growth factors and adapting materials to various clinical contexts. This review provides a comprehensive overview of the current advancements in bone substitute materials, focusing on their biological mechanisms, design considerations, and clinical applications. It explores the role of emerging technologies, such as additive manufacturing and stem cell-based therapies, in advancing the field. Future research highlights the need for multidisciplinary collaboration and rigorous testing to develop advanced bone graft substitutes, improving outcomes and quality of life for patients with complex defects.

Role of Pulsed Electromagnetic Field on Alveolar Bone Remodeling during Orthodontic Retention Phase in Rat Models

Alveolar bone remodeling during the retention phase is essential for successful orthodontic treatment. Pulsed electromagnetic field (PEMF) therapy is an adjunctive therapy for bone-related diseases that induces osteogenesis and prevents bone loss. This study aimed to examine the role of PEMF exposure during the retention phase of orthodontic treatment in alveolar bone remodeling. A total of 36 male Wistar rats were divided into control, PEMF 7, and PEMF 14 groups; a 50 g force nickel-titanium closed-coil spring was inserted to create mesial movement in the first molar for 21 d. Furthermore, the spring was removed, and the interdental space was filled with glass ionomer cement. Concurrently, rats were exposed to a PEMF at 15 Hz with a maximum intensity of 2.0 mT 2 h daily, for 7 and 14 days. Afterwards, the cements were removed and the rats were euthanized on days 1, 3, 7, and 14 to evaluate the expression of Wnt5a mRNA and the levels of RANKL, OPG, ALP, and Runx2 on the tension side. The data were analyzed with ANOVA and post hoc tests, with p < 0.05 declared statistically significant. PEMF exposure significantly upregulated Wnt5a mRNA expression, OPG and ALP levels, and Runx2 expression, and decreased RANKL levels in the PEMF 7 and 14 groups compared to the control group (p < 0.05). This study showed that PEMF exposure promotes alveolar bone remodeling during the orthodontic retention phase on the tension side by increasing alveolar bone formation and inhibiting resorption.

Energizing Healing with Electromagnetic Field Therapy in Musculoskeletal Disorders

There is mounting evidence to suggest that exogenous electromagnetic fields (EMF) may play a significant role in various biological processes that are crucial to therapeutic interventions. EMFs have been identified as a non-invasive, safe, and effective therapy that appears to have no apparent side effects. Numerous studies have demonstrated that pulsed EMFs (PEMFs) have the potential to become a stand-alone or adjunctive treatment modality for managing musculoskeletal disorders. However, several questions remain unresolved. Before their widespread clinical application, further research from well-designed, high-quality studies is required to standardize treatment parameters and determine the optimal protocol for healthcare decision-making. This article provides a comprehensive overview of the impact of musculoskeletal diseases on overall well-being, the limitations of conventional treatments, and the need to explore alternative therapeutic modalities such as electromagnetic field (EMF) therapy. EMF therapy uses low-frequency electromagnetic waves to stimulate tissue repair, reduce inflammation, and modulate pain signals, making it a safe and convenient alternative to conventional treatments. The article also discusses the historical perspective of EMF therapy in medicine. The article highlights the potential of EMF therapy as a personalized and comprehensive care option for musculoskeletal diseases, either alone or in conjunction with other therapies. It emphasizes the imperative for further research in this field and presents a compelling case for the use of EMF therapy in managing musculoskeletal diseases. Overall, the available findings on the underlying cellular and molecular biology support the use of EMF therapy as a viable option for the management of musculoskeletal disorders and stresses the need for continued research in this area.

Application of magnetism in tissue regeneration: recent progress and future prospects

Tissue regeneration is a hot topic in the field of biomedical research in this century. Material composition, surface topology, light, ultrasonic, electric field and magnetic fields (MFs) all have important effects on the regeneration process. Among them, MFs can provide nearly non-invasive signal transmission within biological tissues, and magnetic materials can convert MFs into a series of signals related to biological processes, such as mechanical force, magnetic heat, drug release, etc. By adjusting the MFs and magnetic materials, desired cellular or molecular-level responses can be achieved to promote better tissue regeneration. This review summarizes the definition, classification and latest progress of MFs and magnetic materials in tissue engineering. It also explores the differences and potential applications of MFs in different tissue cells, aiming to connect the applications of magnetism in various subfields of tissue engineering and provide new insights for the use of magnetism in tissue 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.

Promising application of pulsed electromagnetic fields on tissue repair and regeneration

Tissue repair and regeneration is a vital biological process in organisms, which is influenced by various internal mechanisms and microenvironments. Pulsed electromagnetic fields (PEMFs) are becoming a potential medical technology due to its advantages of effectiveness and non-invasiveness. Numerous studies have demonstrated that PEMFs can stimulate stem cell proliferation and differentiation, regulate inflammatory reactions, accelerate wound healing, which is of great significance for tissue regeneration and repair, providing a solid basis for enlarging its clinical application. However, some important issues such as optimal parameter system and potential deep mechanisms remain to be resolved due to PEMFs window effect and biological complexity. Thus, it is of great importance to comprehensively summarizing and analyzing the literature related to the biological effects of PEMFs in tissue regeneration and repair. This review expounded the biological effects of PEMFs on stem cells, inflammation response, wound healing and musculoskeletal disorders in order to improve the application value of PEMFs in medicine. It is believed that with the continuous exploration of biological effects of PEMFs, it will be applied increasingly widely to tissue repair and other diseases.

Ultrasound-derived mechanical stimulation of cell-laden collagen hydrogels for bone repair

Cell therapy is emerging as an effective treatment strategy for many diseases. Here we describe a novel approach to bone tissue repair that combines hydrogel-based cell therapy with low intensity pulsed ultrasound (LIPUS), an FDA approved treatment for fracture repair. Bone marrow-derived stromal cells (BMSCs) have been encapsulated in type I collagen hydrogels and mechanically stimulated using LIPUS-derived acoustic radiation force (ARF). We observed the expression and upward trend of load-sensitive, osteoblast-specific markers and determined that the extent of cell response is dependent on an optimal combination of both hydrogel stiffness and ARF intensity. Specifically, cells encapsulated in hydrogels of optimal stiffness respond at the onset of ultrasound by upregulating early bone-sensitive markers such as calcium, cyclooxygenase-2, and prostaglandin E2 , and later by supporting mineralized tissue formation after 21 days of culture. In vivo evaluation of a critical size calvarial defect in NOD scid gamma (NSG) mice indicated that the implantation of BMSC-laden hydrogels of optimal stiffness improved healing of calvarial defects after daily administration of ARF over 4 weeks. Collectively, these findings validate the efficacy of our system of localized cell delivery for treating bone defects where undifferentiated BMSCs are induced to the osteoblastic lineage. Further, in vivo healing may be enhanced via non-invasive transdermal mechanical stimulation of implanted cells using ARF.

Human Ovarian Follicular Fluid Mesenchymal Stem Cells Express Osteogenic Markers When Cultured on Bioglass 58S-Coated Titanium Scaffolds

Recent studies have reported that stem cells (human follicular fluid mesenchymal stem cells or hFF-MSCs) are present in ovarian follicular fluid (hFF) and that they have a proliferative and differentiative potential which is similar to that of MSCs derived from other adult tissue. These mesenchymal stem cells, isolated from human follicular fluid waste matter discarded after retrieval of oocytes during the IVF process, constitute another, as yet unutilized, source of stem cell materials. There has been little work on the compatibility of these hFF-MSCs with scaffolds useful for bone tissue engineering applications and the aim of this study was to evaluate the osteogenic capacity of hFF-MSCs seeded on bioglass 58S-coated titanium and to provide an assessment of their suitability for bone tissue engineering purposes. Following a chemical and morphological characterization with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), cell viability, morphology and expression of specific osteogenic markers were examined after 7 and 21 days of culture. The hFF-MSCs seeded on bioglass and cultured with osteogenic factors, when compared with those seeded on tissue culture plate or on uncoated titanium, exhibited enhanced cell viability and osteogenic differentiation, as reflected by increased calcium deposition and increased ALP activity with expression and production of bone-related proteins. Taken together, these results demonstrate that MSCs from human follicular fluid waste materials can be easily cultured in titanium scaffolds coated with bioglass, having osteoinductive properties. This process has significant potential for regenerative medicine applications and indicates that hFF-MSCs may be a valid alternative to hBM-MSC cells in experimental models in bone tissue engineering.

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.

Biophysical therapy using the pulsating electromagnetic field as adjunctive therapy for implant osseointegration - A review

Development of procedures which accelerate osseointegration of dental implants, reduce the period of healing, and lead to an early rehabilitation of the patient are required for successful oral rehabilitation. Pulsed electromagnetic field (PEMF) is a noninvasive, therapeutic form of low field magnetic stimulation that has been used for healing bone non unions and various fractures. It acts on osteoblasts and bone, affecting their metabolism, therefore, increasing the tissue integration of the implanted devices and their clinical success. A broad range of settings that includes magnetic field intensity, frequency and duration of application, etc. used for PEMFs stimulation is a hurdle to properly define treatment protocols and extensive research is needed to overcome this issue. The present review includes studies that investigated the effects of PEMFs on the response of bone cells to different classes of biomaterials and the reports that focused on in vivo and in vitro investigations of biomaterials implanted in bone. This study is expected to serve as a guide for researchers and clinicians to bring into their clinical use these strategies to improve implant osseointegration in deficient and osteoporotic bone.

Biomaterials to enhance stem cell transplantation

The successful transplantation of stem cells has the potential to transform regenerative medicine approaches and open promising avenues to repair, replace, and regenerate diseased, damaged, or aged tissues. However, pre-/post-transplantation issues of poor cell survival, retention, cell fate regulation, and insufficient integration with host tissues constitute significant challenges. The success of stem cell transplantation depends upon the coordinated sequence of stem cell renewal, specific lineage differentiation, assembly, and maintenance of long-term function. Advances in biomaterials can improve pre-/post-transplantation outcomes by integrating biophysiochemical cues and emulating tissue microenvironments. This review highlights leading biomaterials-based approaches for enhancing stem cell transplantation.

Effects of Magnetic Stimulation on Dental Implant Osseointegration: A Scoping Review

This PRISMA-ScR driven scoping review aims to evaluate the influence of magnetic field stimulation on dental implant osseointegration. Seven databases were screened adopting ad-hoc strings. All clinical and preclinical studies analyzing the effects of magnetic fields on dental implant osseointegration were included. From 3124 initial items, on the basis of the eligibility criteria, 33 articles, regarding both Pulsed ElectroMagnetic Fields (PEMF) and Static magnetic Fields from permanent Magnets (SFM) were finally included and critically analyzed. In vitro studies showed a positive effect of PEMF, but contrasting effects of SFM on bone cell proliferation, whereas cell adhesion and osteogenic differentiation were induced by both types of stimulation. In vivo studies showed an increased bone-to-implant contact rate in different animal models and clinical studies revealed positive effects on implant stability, under magnetic stimulation. In conclusion, although positive effects of magnetic exposure on osteogenesis activity and osseointegration emerged, this scoping review highlighted the need for further preclinical and clinical studies. More standardized designs, accurate choice of stimulation parameters, adequate methods of evaluation of the outcomes, greater sample size and longer follow-ups are needed to clearly assess the effect of magnetic fields on dental implant osseointegration.

Electromagnetic field exposure as a plausible approach to enhance the proliferation and differentiation of mesenchymal stem cells in clinically relevant scenarios

Mesenchymal stem/stromal cell (MSC)‍-based therapy has been regarded as one of the most revolutionary breakthroughs in the history of modern medicine owing to its myriad of immunoregulatory and regenerative properties. With the rapid progress in the fields of osteo- and musculoskeletal therapies, the demand for MSC-based treatment modalities is becoming increasingly prominent. In this endeavor, researchers around the world have devised new and innovative techniques to support the proliferation of MSCs while minimizing the loss of hallmark features of stem cells. One such example is electromagnetic field (EMF) exposure, which is an alternative approach with promising potential. In this review, we present a critical discourse on the efficiency, practicability, and limitations of some of the relevant methods, with insurmountable evidence backing the implementation of EMF as a feasible strategy for the clinically relevant expansion of MSCs.

Regulatory effects of miR-28 on osteogenic differentiation of human bone marrow mesenchymal stem cells

We aimed to assess the regulatory effects of miR-28 on the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMMSCs). HBMMSCs isolated, cultured and induced (at P3) to undergo osteogenic induction. The expressions of miRNAs were detected by gene microarray, and differentially expressed miRNAs in hBMMSCs compared with induced cells were obtained by significance analysis of microarrays. The microarray findings were confirmed by RT-PCR. TargetScan showed that signal transducer and activator of transcription 1 (STAT1) was the downstream target gene of miR-28. The relationship between miR-28 and STAT1 was validated using dual-luciferase reporter gene assay. HBMMSCs were transfected with miR-28 mimics and STAT1 siRNA, respectively. Samples were collected on day 10 after osteogenic differentiation, and the alkaline phosphatase (AKP) activity, Runt-related transcription factor 2 (RUNX2, a key regulator of osteogenic differentiation) and STAT1 expressions were determined using kits, PCR and Western blotting, respectively. Cell proliferation and migration were detected through CCK-8 and Transwell assays, respectively. During the osteogenic differentiation of hBMMSCs, the expression level of miR-28 increased. MiR-28 specifically bound the 3'-untranslated region (3'UTR) of STAT1 mRNA. It inhibited STAT1 expression in a targeted manner during osteogenic differentiation. Interference with STAT1 partially mimicked the regulatory effects of miR-28 overexpression on the osteogenic differentiation of hBMMSCs. Interference with STAT1 or overexpression of miR-28 did not affect proliferation or migration. MiR-28 has gradually increased expression during the osteogenic differentiation of hBMMSCs, which can directly bind STAT1 3'UTR and inhibit its expression, thereby up-regulating AKP and RUNX2, and promoting osteogenic differentiation.

Altered BMP2/4 Signaling in Stem Cells and Their Niche: Different Cancers but Similar Mechanisms, the Example of Myeloid Leukemia and Breast Cancer

Understanding mechanisms of cancer development is mandatory for disease prevention and management. In healthy tissue, the microenvironment or niche governs stem cell fate by regulating the availability of soluble molecules, cell-cell contacts, cell-matrix interactions, and physical constraints. Gaining insight into the biology of the stem cell microenvironment is of utmost importance, since it plays a role at all stages of tumorigenesis, from (stem) cell transformation to tumor escape. In this context, BMPs (Bone Morphogenetic Proteins), are key mediators of stem cell regulation in both embryonic and adult organs such as hematopoietic, neural and epithelial tissues. BMPs directly regulate the niche and stem cells residing within. Among them, BMP2 and BMP4 emerged as master regulators of normal and tumorigenic processes. Recently, a number of studies unraveled important mechanisms that sustain cell transformation related to dysregulations of the BMP pathway in stem cells and their niche (including exposure to pollutants such as bisphenols). Furthermore, a direct link between BMP2/BMP4 binding to BMP type 1 receptors and the emergence and expansion of cancer stem cells was unveiled. In addition, a chronic exposure of normal stem cells to abnormal BMP signals contributes to the emergence of cancer stem cells, or to disease progression independently of the initial transforming event. In this review, we will illustrate how the regulation of stem cells and their microenvironment becomes dysfunctional in cancer via the hijacking of BMP signaling with main examples in myeloid leukemia and breast cancers.

Evaluation of the Sensing Potential of Stem Cell-Secreted Proteins via a Microchip Device under Electromagnetic Field Stimulation

Most bone tissue engineering models fail to demonstrate the complex cellular functions of living bone; therefore, most translational studies on bone tissue are performed in live models. To reduce the need for live models, we developed a stimulated microchip model for monitoring protein secretion during osteogenesis using human mesenchymal stem cells (hMSCs). We established a bone microchip system for monitoring the in vitro differentiation and sensing the secreted proteins of hMSCs under a sinusoidal electromagnetic field (SEMF), which ameliorates bone healing in a biomimetic natural bone matrix. A 3 V-1 Hz SEMF biophysically stimulated osteogenesis by activating ERK-1/2 and promoting phosphorylation of p38 MAPK kinases. Exposure to a 3 V-1 Hz SEMF upregulated the expression of osteogenesis-related genes and enhanced the expression of key osteoregulatory proteins. We identified 23 proteins that were differentially expressed in stimulated human bone marrow mesenchymal stem cell secretomes or were absent in the control groups. Our on-chip stimulation technology is easy to use, versatile, and nondisruptive and should have diverse applications in regenerative medicine and cell-based therapies.

Biological Responses of Stem Cells to Photobiomodulation Therapy

BACKGROUND

Stem cells have attracted the researchers interest, due to their applications in regenerative medicine. Their self-renewal capacity for multipotent differentiation, and immunomodulatory properties make them unique to significantly contribute to tissue repair and regeneration applications. Recently, stem cells have shown increased proliferation when irradiated with low-level laser therapy or Photobiomodulation Therapy (PBMT), which induces the activation of intracellular and extracellular chromophores and the initiation of cellular signaling. The purpose of this study was to evaluate this phenomenon in the literature.

METHODS

The literature investigated the articles written in English in four electronic databases of PubMed, Scopus, Google Scholar and Cochrane up to April 2019. Stem cell was searched by combining the search keyword of "low-level laser therapy" OR "low power laser therapy" OR "low-intensity laser therapy" OR "photobiomodulation therapy" OR "photo biostimulation therapy" OR "LED". In total, 46 articles were eligible for evaluation.

RESULTS

Studies demonstrated that red to near-infrared light is absorbed by the mitochondrial respiratory chain. Mitochondria are significant sources of reactive oxygen species (ROS). Mitochondria play an important role in metabolism, energy generation, and are also involved in mediating the effects induced by PBMT. PBMT may result in the increased production of (ROS), nitric oxide (NO), adenosine triphosphate (ATP), and cyclic adenosine monophosphate (cAMP). These changes, in turn, initiate cell proliferation and induce the signal cascade effect.

CONCLUSION

The findings of this review suggest that PBMT-based regenerative medicine could be a useful tool for future advances in tissue engineering and cell therapy.

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.

Therapeutic application of light and electromagnetic fields to reduce hyper-inflammation triggered by COVID-19

COVID-19 - related morbidity is associated with exaggerated inflammation and cytokine production in the lungs, leading to acute respiratory failure. The cellular mechanisms underlying these so-called 'cytokine storms' are regulated through the Toll-like receptor 4 (TLR4) signaling pathway and by ROS (Reactive Oxygen Species). Both light (Photobiomodulation) and magnetic fields (e.g., Pulsed Electro Magnetic Field) stimulation are noninvasive therapies known to confer anti-inflammatory effects and regulate ROS signaling pathways. Here we show that daily exposure to two 10-minute intervals of moderate intensity infra-red light significantly lowered the inflammatory response induced via the TLR4 receptor signaling pathway in human cell cultures. Anti-inflammatory effects were likewise achieved by electromagnetic field exposure of cells to daily 10-minute intervals of either Pulsed Electromagnetic Fields (PEMF), or to Low-Level static magnetic fields. Because current illumination and electromagnetic field therapies have no known side effects, and are already approved for some medical uses, we have here developed protocols for verification in clinical trials of COVID-19 infection. These treatments are affordable, simple to implement, and may help to resolve the acute respiratory distress of COVID-19 patients both in the home and in the hospital.

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.

Therapeutic effect of pulsed electromagnetic field on bone wound healing in rats

This study aimed to investigate the therapeutic effect of pulsed electromagnetic field (PEMF) on bone wound in rats as a potential therapy for bone fracture-related conditions. Male rats, aged 3 months, were used to construct model of bone wounding. Wound models were randomly selected to receive PEMF therapy at 1 to 10 mT intensity. Models that did not receive PEMF therapy were used as control. The serum concentrations of calcium (Ca), phosphorus (P) and alkaline phosphatase (ALP) were determined. Bone density and biomechanical properties of callus were measured using a tensile tester. Compared with control, rats subjected to PEMF therapy had similar weight gain, but significantly higher levels of serum Ca and ALP (P < .05) at 5 and 10 mT, while the serum level of P remained unchanged after PEMF therapy. The bone mineral density of callus increased after the therapy, particularly, after 5 and 10 mT therapy (P < .05). Biomechanical measurements showed that 21 days after the therapy, the maximum load, fracture load, elastic load and bending energy were significantly greater in rats receiving 5 and 10 mT PEMF therapy as compared with control (P < .05). Our experiments demonstrate that PEMF at 5 and 10 mT can significantly accelerate wound healing and enhance the repairing ability of bone tissue.

HEK293 cell response to static magnetic fields via the radical pair mechanism may explain therapeutic effects of pulsed electromagnetic fields

PEMF (Pulsed Electromagnetic Field) stimulation has been used for therapeutic purposes for over 50 years including in the treatment of memory loss, depression, alleviation of pain, bone and wound healing, and treatment of certain cancers. However, the underlying cellular mechanisms mediating these effects have remained poorly understood. In particular, because magnetic field pulses will induce electric currents in the stimulated tissue, it is unclear whether the observed effects are due to the magnetic or electric component of the stimulation. Recently, it has been shown that PEMFs stimulate the formation of ROS (reactive oxygen species) in human cell cultures by a mechanism that requires cryptochrome, a putative magnetosensor. Here we show by qPCR analysis of ROS-regulated gene expression that simply removing cell cultures from the Earth’s geomagnetic field by placing them in a Low-Level Field condition induces similar effects on ROS signaling as does exposure of cells to PEMF. This effect can be explained by the so-called Radical Pair mechanism, which provides a quantum physical means by which the rates and product yields (e.g. ROS) of biochemical redox reactions may be modulated by magnetic fields. Since transient cancelling of the Earth’s magnetic field can in principle be achieved by PEMF exposure, we propose that the therapeutic effects of PEMFs may be explained by the ensuing modulation of ROS synthesis. Our results could lead to significant improvements in the design and therapeutic applications of PEMF devices.

Design and experimental validation of a magnetic device for stem cell culture

Cell culture of bone and tendon tissues requires mechanical stimulation of the cells in order to mimic their physiological state. In the present work, a device has been conceived and developed to generate a controlled magnetic field with a homogeneous gradient in the working space. The design requirement was to maximize the magnetic flux gradient, assuring a minimum magnetizing value in a 15 mm × 15 mm working area, which highly increases the normal operating range of this sort of devices. The objective is to use the machine for two types of biological tests: magnetic irradiation of biological samples and force generation on paramagnetic particles embedded in scaffolds for cell culture. The device has been manufactured and experimentally validated by evaluating the force exerted on magnetic particles in a viscous fluid. Apart from the magnetic validation, the device has been tested for irradiating biological samples. In this case, viability of human dental pulp stem cells has been studied in vitro after electromagnetic field exposition using the designed device. After three days of irradiation treatment, cellular microtissues showed a 59% increase in the viable cell number. Irradiated cells did not show morphological differences when compared with control cells.

Recent Advances in Biomaterials for the Treatment of Bone Defects

Bone defects or fractures generally heal in the absence of major interventions due to the high regenerative capacity of bone tissue. However, in situations of severe/large bone defects, these orchestrated regeneration mechanisms are impaired. With advances in modern medicine, natural and synthetic bio-scaffolds from bioceramics and polymers that support bone growth have emerged and gained intense research interest. In particular, scaffolds that recapitulate the molecular cues of extracellular signals, particularly growth factors, offer potential as therapeutic bone biomaterials. The current challenges for these therapies include the ability to engineer materials that mimic the biological and mechanical properties of the real bone tissue matrix, whilst simultaneously supporting bone vascularization. In this review, we discuss the very recent innovative strategies in bone biomaterial technology, including those of endogenous biomaterials and cell/drug delivery systems that promote bone regeneration. We present our understanding of their current value and efficacy, and the future perspectives for bone regenerative medicine.

In Vitro Production of Calcified Bone Matrix onto Wool Keratin Scaffolds via Osteogenic Factors and Electromagnetic Stimulus

Pulsed electromagnetic field (PEMF) has drawn attention as a potential tool to improve the ability of bone biomaterials to integrate into the surrounding tissue. We investigated the effects of PEMF (frequency, 75 Hz; magnetic induction amplitude, 2 mT; pulse duration, 1.3 ms) on human osteoblast-like cells (SAOS-2) seeded onto wool keratin scaffolds in terms of proliferation, differentiation, and production of the calcified bone extracellular matrix. The wool keratin scaffold offered a 3D porous architecture for cell guesting and nutrient diffusion, suggesting its possible use as a filler to repair bone defects. Here, the combined approach of applying a daily PEMF exposure with additional osteogenic factors stimulated the cells to increase both the deposition of bone-related proteins and calcified matrix onto the wool keratin scaffolds. Also, the presence of SAOS-2 cells, or PEMF, or osteogenic factors did not influence the compression behavior or the resilience of keratin scaffolds in wet conditions. Besides, ageing tests revealed that wool keratin scaffolds were very stable and showed a lower degradation rate compared to commercial collagen sponges. It is for these reasons that this tissue engineering strategy, which improves the osteointegration properties of the wool keratin scaffold, may have a promising application for long term support of bone formation in vivo.

Effects of Electromagnetic Field on Proliferation, Differentiation, and Mineralization of MC3T3 Cells

IMPACT STATEMENT

We present the study about how the parameters of pulsed electromagnetic field (PEMF) stimulus affected calvarial osteoblast precursor cell in terms of growth, viability, and differentiation. This research provides insight and foundation to clinical application of noninvasive therapy using PEMF to improve bone regeneration.

Electromagnetic field treatment increases purinergic receptor P2X7 expression and activates its downstream Akt/GSK3β/β-catenin axis in mesenchymal stem cells under osteogenic induction

Background

Imbalance in bone formation and resorption is a crucial component of the pathological process leading to osteoporosis. Electromagnetic fields (EMFs) have been reported to be beneficial to osteogenesis, although the exact mechanism has not been fully clarified. Purinergic receptor P2X7 is expressed in osteoblasts and is reported to participate in the regulation of bone metabolism.

Objectives

To elucidate the link between EMFs and P2X7 expression and investigate its potential as a novel therapeutic target in osteoporosis.

Method

We investigated the effect of EMFs on P2X7 expression and downstream signaling in human bone marrow mesenchymal stem cells (h-MSCs). We also established an ovariectomized (OVX) osteoporosis rat model to evaluate the therapeutic efficacy of combining EMFs with P2X7 agonists.

Results

EMF treatment increased P2X7 expression in h-MSCs under conditions of osteogenic induction but not under regular culture conditions. P2X7 or PI3K/Akt inhibition partially inhibited the pro-osteogenic effect of EMF and lowered the EMF-stimulated activity of the Akt/GSK3β/β-catenin axis. No additive effect of this suppression was observed following simultaneous inhibition of P2X7 and PI3K/Akt. EMF treatment in the presence of a P2X7 agonist had a greater effect in increasing osteogenic marker expression than that of EMF treatment alone. In the OVX osteoporosis model, the therapeutic efficacy of combining EMFs with P2X7 agonists was superior to that of EMF treatment alone.

Conclusions

EMF treatment increases P2X7 expression by h-MSCs during osteogenic differentiation, leading to activation of the Akt/GSK3β/β-catenin axis, which promotes the osteogenesis. Our findings also indicate that combined EMF and P2X7 agonist treatment may be an effective novel strategy for osteoporosis therapy.

Scleral ossicles: angiogenic scaffolds, a novel biomaterial for regenerative medicine applications

Given the current prolonged life expectancy, various pathologies affect increasingly the aging subjects. Regarding the musculoskeletal apparatus, bone fragility induces more susceptibility to fractures, often not accompanied by good ability of self-repairing, in particular when critical-size defects (CSD) occur. Currently orthopedic surgery makes use of allografting and autografting which, however, have limitations due to the scarce amount of tissue that can be taken from the donor, the possibility of disease transmission and donor site morbidity. The need to develop new solutions has pushed the field of tissue engineering (TE) research to study new scaffolds to be functionalized in order to obtain constructs capable of promoting tissue regeneration and achieve stable bone recovery over time. This investigation focuses on the most important aspect related to bone tissue regeneration: the angiogenic properties of the scaffold to be used. As an innovative solution, scleral ossicles (SOs), previously characterized as natural, biocompatible and spontaneously decellularized scaffolds used for bone repair, were tested for angiogenic potential and biocompatibility. To reach this purpose, in ovo Chorioallantoic Membrane Assay (CAM) was firstly used to test the angiogenic potential; secondly, in vivo subcutaneous implantation of SOs (in a rat model) was performed in order to assess the biocompatibility and the inflammatory response. Finally, thanks to the analysis of mass spectrometry (LCMSQE), the putative proteins responsible for the SO angiogenic properties were identified. Thus, a novel natural biomaterial is proposed, which is (i) able to induce an angiogenic response in vivo by subcutaneous implantation in a non-immunodeficient animal model, (ii) which does not induce any inflammatory response, and (iii) is useful for regenerative medicine application for the healing of bone CSD.

The NATO project: nanoparticle-based countermeasures for microgravity-induced osteoporosis

Recent advances in nanotechnology applied to medicine and regenerative medicine have an enormous and unexploited potential for future space and terrestrial medical applications. The Nanoparticles and Osteoporosis (NATO) project aimed to develop innovative countermeasures for secondary osteoporosis affecting astronauts after prolonged periods in space microgravity. Calcium- and Strontium-containing hydroxyapatite nanoparticles (nCa-HAP and nSr-HAP, respectively) were previously developed and chemically characterized. This study constitutes the first investigation of the effect of the exogenous addition of nCa-HAP and nSr-HAP on bone remodeling in gravity (1 g), Random Positioning Machine (RPM) and onboard International Space Station (ISS) using human bone marrow mesenchymal stem cells (hBMMSCs). In 1 g conditions, nSr-HAP accelerated and improved the commitment of cells to differentiate towards osteoblasts, as shown by the augmented alkaline phosphatase (ALP) activity and the up-regulation of the expression of bone marker genes, supporting the increased extracellular bone matrix deposition and mineralization. The nSr-HAP treatment exerted a protective effect on the microgravity-induced reduction of ALP activity in RPM samples, and a promoting effect on the deposition of hydroxyapatite crystals in either ISS or 1 g samples. The results indicate the exogenous addition of nSr-HAP could be potentially used to deliver Sr to bone tissue and promote its regeneration, as component of bone substitute synthetic materials and additive for pharmaceutical preparation or food supplementary for systemic distribution.

Carbon nanotube/iron oxide hybrid particles and their PCL-based 3D composites for potential bone regeneration

This study describes the preparation, and evaluates the biocompatibility, of hydroxylated multi-walled carbon nanotubes (fCNTs) functionalized with magnetic iron oxide nanoparticles (IONs) creating hybrid nanoparticles. These nanoparticles were used for preparing a composite porous poly(ε-caprolactone) scaffolds for potential utilization in regenerative medicine. Hybrid fCNT/ION nanoparticles were prepared in two mass ratios - 1:1 (H1) and 1:4 (H4). PCL scaffolds were prepared with various concentrations of the nanoparticles with fixed mass either of the whole nanoparticle hybrid or only of the fCNTs. The hybrid particles were evaluated in terms of morphology, composition and magnetic properties. The cytotoxicity of the hybrid nanoparticles and the pure fCNTs was assessed by exposing the SAOS-2 human cell line to colloids with a concentration range from 0.01 to 1 mg/ml. The results indicate a gradual increase in the cytotoxicity effect with increasing concentration. At low concentrations, interestingly, SAOS-2 metabolic activity was stimulated by the presence of IONs. The PCL scaffolds were characterized in terms of the scaffold architecture, the dispersion of the nanoparticles within the polymer matrix, and subsequently in terms of their thermal, mechanical and magnetic properties. A higher ION content was associated with the presence of larger agglomerates of particles. With exception of the scaffold with the highest content of the H4 nanoparticle hybrid, all composites were superparamagnetic. In vitro tests indicate that both components of the hybrid nanoparticles may have a positive impact on the behavior of SAOS-2 cells cultivated on the PCL composite scaffolds. The presence of fCNTs up to 1 wt% improved the cell attachment to the scaffolds, and a content of IONs below 1 wt% increased the cell metabolic activity.

The Use of Pulsed Electromagnetic Fields to Promote Bone Responses to Biomaterials In Vitro and In Vivo

Implantable biomaterials are extensively used to promote bone regeneration or support endosseous prosthesis in orthopedics and dentistry. Their use, however, would benefit from additional strategies to improve bone responses. Pulsed Electromagnetic Fields (PEMFs) have long been known to act on osteoblasts and bone, affecting their metabolism, in spite of our poor understanding of the underlying mechanisms. Hence, we have the hypothesis that PEMFs may also ameliorate cell responses to biomaterials, improving their growth, differentiation, and the expression of a mature phenotype and therefore increasing the tissue integration of the implanted devices and their clinical success. A broad range of settings used for PEMFs stimulation still represents a hurdle to better define treatment protocols and extensive research is needed to overcome this issue. The present review includes studies that investigated the effects of PEMFs on the response of bone cells to different classes of biomaterials and the reports that focused on in vivo investigations of biomaterials implanted in bone.