Pulsed electromagnetic fields protect the balance between adipogenesis and osteogenesis on steroid-induced osteonecrosis of femoral head at the pre-collapse stage in rats

Reciprocal Effect of Environmental Stimuli to Regulate the Adipogenesis and Osteogenesis Fate Decision in Bone Marrow-Derived Mesenchymal Stem Cells (BM-MSCs)

Mesenchymal stem cells derived from bone marrow (BM-MSCs) can differentiate into adipocytes and osteoblasts. Various external stimuli, including environmental contaminants, heavy metals, dietary, and physical factors, are shown to influence the fate decision of BM-MSCs toward adipogenesis or osteogenesis. The balance of osteogenesis and adipogenesis is critical for the maintenance of bone homeostasis, and the interruption of BM-MSCs lineage commitment is associated with human health issues, such as fracture, osteoporosis, osteopenia, and osteonecrosis. This review focuses on how external stimuli shift the fate of BM-MSCs towards adipogenesis or osteogenesis. Future studies are needed to understand the impact of these external stimuli on bone health and elucidate the underlying mechanisms of BM-MSCs differentiation. This knowledge will inform efforts to prevent bone-related diseases and develop therapeutic approaches to treat bone disorders associated with various pathological conditions.

Evidence of the static magnetic field effects on bone-related diseases and bone cells

Static magnetic fields (SMFs), magnetic fields with constant intensity and orientation, have been extensively studied in the field of bone biology both fundamentally and clinically as a non-invasive physical factor. A large number of animal experiments and clinical studies have shown that SMFs have effective therapeutic effects on bone-related diseases such as non-healing fractures, bone non-union of bone implants, osteoporosis and osteoarthritis. The maintenance of bone health in adults depends on the basic functions of bone cells, such as bone formation by osteoblasts and bone resorption by osteoclasts. Numerous studies have revealed that SMFs can regulate the proliferation, differentiation, and function of bone tissue cells, including bone marrow mesenchymal stem cells (BMSCs), osteoblasts, bone marrow monocytes (BMMs), osteoclasts, and osteocytes. In this paper, the effects of SMFs on bone-related diseases and bone tissue cells are reviewed from both in vivo studies and in vitro studies, and the possible mechanisms are analyzed. In addition, some challenges that need to be further addressed in the research of SMF and bone are also discussed.

Revealing the mechanisms of Weishi Huogu I capsules used for treating osteonecrosis of the femoral head based on systems pharmacology with one mechanism validated with in vitro experiments

ETHNOPHARMACOLOGICAL RELEVANCE

Weishi Huogu I (WH I) capsules, developed through traditional Chinese medicine, have been used to treat clinical osteonecrosis of the femoral head (ONFH) for decades. However, the mechanisms have not been systematically studied.

AIM OF THE STUDY

In this study, the mechanisms of WH I capsules used in treating ONFH were examined through a systems pharmacology strategy, and one mechanism was validated with in vitro experiments.

MATERIALS AND METHODS

WH I capsules compounds were identified by screening databases; then, a database of the potential active compounds was constructed after absorption, distribution, metabolism and excretion (ADME) evaluation. The compounds were identified through a systematic approach in which the probability of an interaction of every candidate compound with each corresponding target in the DrugBank database was calculated. Gene Ontology (GO) and pathway enrichment analyses of the targets was performed with the Metascape and KEGG DISEASE databases. Then, a compound-target network (C-T) and target-pathway network (T-P) of WH I capsule components were constructed, and network characteristics and related information were used for systematically identifying WH I capsule multicomponent-target interactions. Furthermore, the effects of WH I capsule compounds identified through the systematic pharmacology analysis of the osteogenic transformation of human umbilical mesenchymal stem cells (HUMSCs) were validated in vitro.

RESULTS

In total, 152 potentially important compounds and 176 associated targets were identified. Twenty-two crucial GO biological process (BP) or pathways were related to ONFH, mainly in regulatory modules regulating blood circulation, modulating growth, and affecting pathological processes closely related to ONFH. Furthermore, the GO enrichment analysis showed that corydine, isorhamnetin, and bicuculline were enriched in "RUNX2 regulates osteoblast differentiation", significantly increased alkaline phosphatase activity and calcium deposition and upregulated runt-related transcription factor 2 mRNA and protein expression and osteocalcin mRNA expression in HUMSCs, suggesting that these compounds promoted the mesenchymal stem cell (MSC) osteogenic transformation.

CONCLUSIONS

The study showed that the pharmacological mechanisms of WH I capsule attenuation of ONFH mainly involve three therapeutic modules: blood circulation, modulating growth, and regulating pathological processes. The crosstalk between GOBPs/pathways may constitute the basis of the synergistic effects of the compounds in WH I capsules in attenuating ONFH. One of the pharmacological mechanisms in the WH I capsule effect on ONFH involves enhancement of the osteogenic transformation of MSCs, as validated in experiments performed in vitro; however, more mechanisms should be validated in further studies.

Pulsed Electro-Magnetic Field (PEMF) Effect on Bone Healing in Animal Models: A Review of Its Efficacy Related to Different Type of Damage

Simple Summary

Pulsed electromagnetic fields (PEMFs) are a type of biophysical stimulation that has been shown to be effective in improving bone regeneration and preventing bone loss. Their use dates back to the 1970s, but a gold standard treatment protocol has not yet been defined. PEMF efficacy relies on the generation of biopotentials, which activate several molecular pathways. There is currently no clear understanding of the effects on bone healing and, in addition, there are several animal models relevant to this issue. Therefore, drawing guidelines and conclusions from the analysis of the studies is difficult. In vivo investigations on PEMF stimulation are reviewed in this paper, focusing on molecular and morphological improvements in bone. Currently, there is little knowledge about the biological mechanism of PEMF and its effect on bone healing. This is due to the variability of crucial characteristics of electro-magnetic fields, such as amplitude and exposure frequency, which may influence the type of biological response. Furthermore, a different responsiveness of cells involved in the bone healing process is documented. Heterogeneous setting parameters and different outcome measures are considered in various animal models. Therefore, achieving comparable results is difficult.

Abstract

Biophysical energies are a versatile tool to stimulate tissues by generating biopotentials. In particular, pulsed electromagnetic field (PEMF) stimulation has intrigued researchers since the 1970s. To date, many investigations have been carried out in vivo, but a gold standard treatment protocol has not yet been defined. The main obstacles are represented by the complex setting of PEMF characteristics, the variety of animal models (including direct and indirect bone damage) and the lack of a complete understanding of the molecular pathways involved. In the present review the main studies about PEMF stimulation in animal models with bone impairment were reviewed. PEMF signal characteristics were investigated, as well as their effect on molecular pathways and osseous morphological features. We believe that this review might be a useful starting point for a prospective study in a clinical setting. Consistent evidence from the literature suggests a potential beneficial role of PEMF in clinical practice. Nevertheless, the wide variability of selected parameters (frequency, duration, and amplitude) and the heterogeneity of applied protocols make it difficult to draw certain conclusions about PEMF effectiveness in clinical implementation to promote bone healing. Deepening the knowledge regarding the most consistent results reported in literature to date, we believe that this review may be a useful starting point to propose standardized experimental guidelines. This might provide a solid base for further controlled trials, to investigate PEMF efficacy in bone damage conditions during routine clinical practice.

Long-term effect of full-body pulsed electromagnetic field and exercise protocol in the treatment of men with osteopenia or osteoporosis: A randomized placebo-controlled trial

Background: Osteoporosis is the most prevalent metabolic disease affecting bones. Objective: To investigate the long-term effect of pulsed electromagnetic field (PEMF) combined with exercise protocol on bone mineral density (BMD) and bone markers in men with osteopenia or osteoporosis. Methods: Ninety-five males with osteopenia or osteoporosis (mean age, 51.26 ± 2.41 years; mean height, 176 ± 2.02 cm; mean weight, 83.08 ± 2.60 kg; mean body–mass index (BMI), 26.08 ± 1.09 kg/m ²) participated in the study, and they were randomly assigned to one of three groups: Group 1 received a full-body PEMF and exercise protocol (PEMF +EX), Group 2 received a placebo full-body PEMF and exercise protocol (PPEMF +EX), and Group 3 received a full-body PEMF alone (PEMF). PEMF was applied for the whole body using a full-body mat three times per week for 12 weeks, with an exercise protocol that includes flexibility, aerobic exercise, strengthening, weight-bearing, and balance exercises followed by whole-body vibration (WBV) training. Outcome measures include BMD of total hip and lumbar spine and bone markers [serum osteocalcin (s-OC), Serum amino-terminal cross-linking telopeptide of type I collagen (s-NTX), Serum carboxy-terminal cross-linking telopeptide of type I collagen (s-CTX), Parathyroid hormones (PTH), Bone-specific Alkaline Phosphatase (BSAP), and 25-hydroxy vitamin D (Vit D)]. Results: The BMD of total hip and lumbar spine was significantly increased post-treatment in all groups, and more so in Group 1 and Group 2 than Group 3. There was a significant difference in bone markers in all groups, more so in Group 1 and Group 2 than in Group 3. Conclusion: PEMF combined with exercise protocol exerts a potent role for treating OP, is more effective than exercise and PEMF alone for increasing BMD and enhancing bone formation, and suppresses bone-resorption markers after 12-weeks of treatment with the impact lasting up to 6 months.

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.

Magnetic Resonance Spectroscopy for Evaluating the Effect of Pulsed Electromagnetic Fields on Marrow Adiposity in Postmenopausal Women With Osteopenia

OBJECTIVE

Pulsed electromagnetic fields (PEMFs) could promote osteogenic differentiation and suppress adipogenic differentiation in bone mesenchymal stem cells ex vivo. However, data on the effect of PEMF on marrow adiposity in humans remain elusive. We aimed to determine the in vivo effect of PEMF on marrow adiposity in postmenopausal women using magnetic resonance spectroscopy.

METHODS

Sixty-one postmenopausal women with osteopenia, aged 53 to 85 years, were randomly assigned to receive either PEMF treatment or placebo. The session was performed 3 times per week for 6 months. All women received adequate dietary calcium and vitamin D. Bone mineral density (BMD) by dual-energy x-ray absorptiometry, vertebral marrow fat content by magnetic resonance spectroscopy, and serum biomarkers were evaluated before and after 6 months of treatment.

RESULTS

A total of 27 (87.1%) and 25 (83.3%) women completed the treatment schedule in the PEMF and placebo groups, respectively. After the 6-month treatment, lumbar spine and hip BMD increased by 1.46% to 2.04%, serum bone-specific alkaline phosphatase increased by 3.23%, and C-terminal telopeptides of type 1 collagen decreased by 9.12% in the PEMF group (P < 0.05), whereas the mean percentage changes in BMD and serum biomarkers were not significant in the placebo group. Pulsed electromagnetic field treatment significantly reduced marrow fat fraction by 4.81%. The treatment difference between the 2 groups was -4.43% (95% confidence interval, -3.70% to -5.65%; P = 0.009).

CONCLUSIONS

Pulsed electromagnetic field is an effective physiotherapy in postmenopausal women, and this effect may, at least in part, regulate the amount of fat within the bone marrow. Magnetic resonance spectroscopy may serve as a complementary imaging biomarker for monitoring response to therapy in osteoporosis.

Forced acoustic oscillations of biological cell

This article considers the possibility of excitation of acoustic oscillations in a cell by electromagnetic waves. In this process, not only the frequency but also the length of a wave is of great importance. It is also reported that the pulse signal can be more effective than harmonic signal, and the pulse length is not essential. In accordance with this fact, it is possible to explain the biological effects of electromagnetic waves and to develop new medical electronic devices. Bioelectromagnetics. 38:613-617, 2017. © 2017 Wiley Periodicals, Inc.

Osteonecrosis in children and adolescents with acute lymphoblastic leukemia: a therapeutic challenge

Osteonecrosis (ON) represents one of the most common and debilitating sequelae of antileukemic treatment in children and adolescents with acute lymphoblastic leukemia (ALL). Systematic screening strategies can focus on early detection and intervention to prevent ON from progressing to stages associated with pain and functional impairment. These strategies hold promise for reducing ON-associated morbidity without the risk of impairing leukemia control. Herein, we critically reviewed clinical data on pharmacological, nonpharmacological/nonsurgical, and surgical (including cellular) treatment options for ON, which are covered in the literature and/or are conceivable based on the supposed underlying ON pathophysiology. Prevention of ON progression is of paramount importance, and attempts seem to be more effective in early (precollapse) disease status than in late-stage (collapse) ON. Based on the results of ongoing prospective magnetic resonance imaging screening studies, which will hopefully identify those patients with a high risk of ON progression and debilitating sequelae, prospective interventional studies are urgently needed. Although there is still a lack of high-quality studies, based on currently available data, core decompression surgery combined with cellular therapies (eg, employing mesenchymal stem cells) appears most promising for preventing joint infraction in children at high risk of developing late-stage ON.

Ethyl acetate fraction of Huogu formula inhibits adipogenic differentiation of bone marrow stromal cells via the BMP and Wnt signaling pathways

Elevated adipogenesis of bone marrow stromal cells (BMSCs) is closely associated with non-traumatic osteonecrosis of femoral head (ONFH). Our previous studies have shown that Huogu (HG) formula was effective both in clinic experience and experimental ONFH. How HG impacts the differentiation of BMSCs and what is the underlying molecular mechanism remain largely unknown. Our results showed that ethyl acetate extract of HG (HGE) significantly decreased the adipocyte differentiation as determined by oil red staining, while slightly increased the ALP activity. Investigation of the molecular mechanism revealed that HGE could inhibit the mRNA and protein expression of peroxisome proliferators-activated receptor (PPAR)γ, lipoprotein lipase (LPL) and adipocyteprotein2 (AP2). Interestingly, the inhibition of adipogenic differentiation in BMSCs by HGE could be restored by DKK-1, an inhibitor of Wnts. However, Noggin (an inhibitor of BMPs) displayed an additive role with HGE in suppressing the expression of PPARγ, LPL, and AP2. Furthermore, the bone marrow fat formation, as well as the expression of Wnt3a and PPARγ, was effectively regulated by HGE in the steroid-induced ONFH rats. Our results demonstrated that HGE treatment significantly inhibited adipogenesis and slightly promoted osteogenesis of BMSCs through regulating the BMP and Wnt pathways. The findings shed lights on the molecular mechanism of HGE in the inhibition of adipogenesis and provide scientific rationale for its clinical application of HGE in the treatment of ONFH.

Modulation of Osteogenesis in MC3T3-E1 Cells by Different Frequency Electrical Stimulation

Electrical stimulation (ES) is therapeutic to many bone diseases, from promoting fracture regeneration to orthopedic intervention. The application of ES offers substantial therapeutic potential, while optimal ES parameters and the underlying mechanisms responsible for the positive clinical impact are poorly understood. In this study, we assembled an ES cell culture and monitoring device. Mc-3T3-E1 cells were subjected to different frequency to investigate the effect of osteogenesis. Cell proliferation, DNA synthesis, the mRNA levels of osteosis-related genes, the activity of alkaline phosphatase (ALP), and intracellular concentration of Ca²⁺ were thoroughly evaluated. We found that 100 Hz could up-regulate the mRNA levels of collagen I, collagen II and Runx2. On the contrary, ES could down-regulate the mRNA levels of osteopontin (OPN). ALP activity assay and Fast Blue RR salt stain showed that 100 Hz could accelerate cells differentiation. Compared to the control group, 100 Hz could promote cell proliferation. Furthermore, 1 Hz to 10 Hz could improve calcium deposition in the intracellular matrix. Overall, these results indicate that 100Hz ES exhibits superior potentialities in osteogenesis, which should be beneficial for the clinical applications of ES for the treatment of bone diseases.

Effect of Pulsed Electromagnetic Field on Bone Formation and Lipid Metabolism of Glucocorticoid-Induced Osteoporosis Rats through Canonical Wnt Signaling Pathway

Pulsed electromagnetic field (PEMF) has been suggested as a promising method alternative to drug-based therapies for treating osteoporosis (OP), but the role of PEMF in GIOP animal models still remains unknown. This study was performed to investigate the effect of PEMF on bone formation and lipid metabolism and further explored the several important components and targets of canonical Wnt signaling pathway in GIOP rats. After 12 weeks of intervention, bone mineral density (BMD) level of the whole body increased significantly, serum lipid levels decreased significantly, and trabeculae were thicker in GIOP rats of PEMF group. PEMF stimulation upregulated the mRNA and protein expression of Wnt10b, LRP5, β-catenin, OPG, and Runx2 and downregulated Axin2, PPAR-γ, C/EBPα, FABP4, and Dkk-1. The results of this study suggested that PEMF stimulation can prevent bone loss and improve lipid metabolism disorders in GIOP rats. Canonical Wnt signaling pathway plays an important role in bone formation and lipid metabolism during PEMF stimulation.

Steroid-associated osteonecrosis: Epidemiology, pathophysiology, animal model, prevention, and potential treatments (an overview)

Steroid-associated osteonecrosis (SAON) is a common orthopaedic problem caused by administration of corticosteroids prescribed for many nonorthopaedic medical conditions. We summarised different pathophysiologies of SAON which have adverse effects on multiple systems such as bone marrow stem cells (BMSCs) pool, bone matrix, cell apoptosis, lipid metabolism, and angiogenesis. Different animal models were introduced to mimic the pathophysiology of SAON and for testing the efficacy of both prevention and treatment effects of various chemical drugs, biological, and physical therapies. According to the classification of SAON, several prevention and treatment methods are applied at the different stages of SAON. For the current period, Chinese herbs may also have the potential to prevent the occurrence of SAON. In the future, genetic analysis might also be helpful to effectively predict the development of ON and provide information for personalised prevention and treatment of patients with SAON.