Remodeling Effects of the Combination of GGT Scaffolds, Percutaneous Electrical Stimulation, and Acupuncture on Large Bone Defects in Rats

Enhancing Bone Health with Conjugated Linoleic Acid: Mechanisms, Challenges, and Innovative Strategies

Conjugated linoleic acid (CLA) is a bioactive compound known for its anti-inflammatory, anti-carcinogenic, and metabolic effects, with growing interest in its role in supporting bone health. Preclinical studies, particularly those involving the t10c12 isomer, have shown that CLA can enhance bone mineral density (BMD) by enhancing bone formation and reducing bone resorption, indicating its potential as a therapeutic agent to improve bone health. However, clinical trials have yielded inconsistent results, underscoring the difficulty in translating animal model successes to human applications. A major challenge is CLA's low water solubility, poor absorption, and limited bioavailability, which restrict its therapeutic effectiveness. To address these issues, nanoparticle-based delivery systems have been proposed to improve its solubility, stability, and resistance to oxidative damage, thereby enhancing its bioactivity. Recent studies also suggest that electrical stimulation can stimulate bone regeneration by promoting bone cell proliferation, differentiation, and adherence to scaffolds. This review explores the combined use of CLA supplementation and electrical stimulation as a novel approach to improving bone health, particularly in osteoporosis management. By integrating CLA's biological effects with the regenerative potential of electrical stimulation, this multimodal strategy offers a promising method for enhancing bone restoration, with significant implications for clinical applications in bone health.

Numerical Simulation of the Effect of Electrical Stimulation on Disuse After Hip Replacement

Background: Total hip replacement replaces the femoral head, which cannot heal, with an artificial femoral shaft to ensure the patient's normal life. However, due to the stress-masking effect of the proximal femur loaded with the artificial femur stem, the implant bears a large part of the load, resulting in insufficient stress stimulation of the proximal femur and bone waste remodeling. In turn, it is easy to lose bone, resulting in loosening. As a new treatment method, electrical stimulation has been widely used for bone loss, nonunion, and other diseases, and it has achieved good therapeutic effects. Methods: Therefore, in this work, electrical stimulation was introduced for postoperative density assessment, and a new disuse remodeling model was established to simulate density loss after remodeling and the resistance effect of electrical stimulation. The effects of various parameters on density loss in the model are discussed. Results: The simulation results revealed significant stress masking and density loss in the neck of the femur after hip replacement, and electrical stimulation placed in the neck of the femur may resist this density loss to a certain extent. The rate of bone mineral density reduction decreased after the addition of electrical stimulation, indicating that electrical stimulation can have a certain resistance to the density reduction caused by stress shielding, and this result is helpful for the rehabilitation of hip arthroplasty.

Efficacy of acupuncture for primary osteoporosis: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Primary osteoporosis (POP) is a common metabolic bone disorder that has a devastating effect on their quality of life in patients. Acupuncture, a traditional Chinese therapy, has been used to treat osteoporosis for over 2000 years. This study aimed to determine the efficacy of acupuncture in treating POP compared to conventional medicine or placebo.

METHODS

We searched for potentially relevant studies in PubMed, Web of Science, Embase, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, China Biology Medicine disc, Wanfang database and ClinicalTrials.gov up to December 20, 2024. Randomized controlled trials investigating treatment of POP for which acupuncture was administered as a stand-alone treatment or combined with conventional medicine compared to conventional medicine or placebo, were included. The outcomes included bone mineral density (BMD), visual analogue scale (VAS) scores, clinical effectiveness rate, estradiol (E2), Oswestry Disability Index (ODI), and levels of serum alkaline phosphatase (ALP). Data were synthesized using a random-effects meta-analysis model, and the observed heterogeneity was investigated using subgroup analyses. Study quality was appraised using the Cochrane RoB 2 tools, and the quality of the aggregated evidence was evaluated using the GRADE guidelines. Publication bias was assessed by funnel plots and validated by Egger's test.

RESULTS

Forty eligible articles with 2654 participants were identified. Compared to the control group, acupuncture effectively increased the BMD (MD 0.04 [0.03-0.06], P < 0.001, I2 = 92%), clinical efficacy (RR 1.24 [1.14-1.34], P < 0.001, I2 = 81%), and levels of E2 (SMD 0.30 [0.09-0.52], P = 0.006, I2 = 0%), and reduced the VAS scores (SMD - 1.79 [- 2.29 to - 1.29], P < 0.001, I2 = 95%). Data on ODI and ALP were insufficient for meta-analysis.

CONCLUSION

The current evidence suggests that the efficacy of acupuncture in improving the symptoms of POP are encouraging for its use in clinical practice as a physical intervention for patients with POP. However, since the included patients were all from China, there was a risk of sample bias, high-quality multicenter studies in different countries or regions should be conducted in the future.

Unleashing the Potential of Electroactive Hybrid Biomaterials and Self-Powered Systems for Bone Therapeutics

The incidence of large bone defects caused by traumatic injury is increasing worldwide, and the tissue regeneration process requires a long recovery time due to limited self-healing capability. Endogenous bioelectrical phenomena have been well recognized as critical biophysical factors in bone remodeling and regeneration. Inspired by bioelectricity, electrical stimulation has been widely considered an external intervention to induce the osteogenic lineage of cells and enhance the synthesis of the extracellular matrix, thereby accelerating bone regeneration. With ongoing advances in biomaterials and energy-harvesting techniques, electroactive biomaterials and self-powered systems have been considered biomimetic approaches to ensure functional recovery by recapitulating the natural electrophysiological microenvironment of healthy bone tissue. In this review, we first introduce the role of bioelectricity and the endogenous electric field in bone tissue and summarize different techniques to electrically stimulate cells and tissue. Next, we highlight the latest progress in exploring electroactive hybrid biomaterials as well as self-powered systems such as triboelectric and piezoelectric-based nanogenerators and photovoltaic cell-based devices and their implementation in bone tissue engineering. Finally, we emphasize the significance of simulating the target tissue's electrophysiological microenvironment and propose the opportunities and challenges faced by electroactive hybrid biomaterials and self-powered bioelectronics for bone repair strategies.

Electroacupuncture ameliorates senile osteoporosis by promoting bone remodeling and regulating autophagy

OBJECTIVES

Osteoporosis is widely regarded as a typical aged-related disease caused by impaired bone remodeling. This research was designed to explore the protective effects of electroacupuncture (EA) on senile osteoporosis in a rat model and investigate the underlying mechanisms.

METHODS

Three-month-old rats were randomly selected as the youth group, and 24-month-old rats were randomly assigned to the elderly and EA groups. Rats in the EA group received 30 min of EA at bilateral SP10, ST36, K13 and GB34 daily, 5 days a week for 8 weeks. Bone mineral density (BMD), microstructure of the bone tissue, bone turnover biomarkers and expression level of autophagy-related proteins were detected.

RESULTS

Compared with the elderly group, EA treatment significantly increased BMD of the femur and ameliorated the microstructure. EA treatment increased trabecular bone volume ratio (= bone volume / total volume [BV/TV]) and trabecular number (Tb.N) and decreased trabecular separation (Tb.Sp) in senile osteoporosis rats. Compared with the elderly group, the serum N-terminal telopeptide of type I collagen (NTX1) level in the EA group was lower, and the serum procollagen type I N-terminal propeptide (PINP) concentration was higher. In addition, the expression of Beclin 1, microtubule-associated protein I light chain 3 (LC3B) and P62 was inhibited in the senile osteoporosis rats after EA treatment.

CONCLUSIONS

EA can effectively alleviate aging-related bone loss and improve the microstructure of bone tissue in senile osteoporosis rats, and the regulation of autophagy might be one of the important mechanisms.

Accelerated Bone Healing via Electrical Stimulation

Piezoelectric effect produces an electrical signal when stress is applied to the bone. When the integrity of the bone is destroyed, the biopotential within the defect site is reduced and several physiological responses are initiated to facilitate healing. During the healing of the bone defect, the bioelectric potential returns to normal levels. Treatment of fractures that exceed innate regenerative capacity or exhibit delayed healing requires surgical intervention for bone reconstruction. For bone defects that cannot heal on their own, exogenous electric fields are used to assist in treatment. This paper reviews the effects of exogenous electrical stimulation on bone healing, including osteogenesis, angiogenesis, reduction in inflammation and effects on the peripheral nervous system. This paper also reviews novel electrical stimulation methods, such as small power supplies and nanogenerators, that have emerged in recent years. Finally, the challenges and future trends of using electrical stimulation therapy for accelerating bone healing are discussed.

Advances in electroactive biomaterials: Through the lens of electrical stimulation promoting bone regeneration strategy

The regenerative capacity of bone is indispensable for growth, given that accidental injury is almost inevitable. Bone regenerative capacity is relevant for the aging population globally and for the repair of large bone defects after osteotomy (e.g., following removal of malignant bone tumours). Among the many therapeutic modalities proposed to bone regeneration, electrical stimulation has attracted significant attention owing to its economic convenience and exceptional curative effects, and various electroactive biomaterials have emerged. This review summarizes the current knowledge and progress regarding electrical stimulation strategies for improving bone repair. Such strategies range from traditional methods of delivering electrical stimulation via electroconductive materials using external power sources to self-powered biomaterials, such as piezoelectric materials and nanogenerators. Electrical stimulation and osteogenesis are related via bone piezoelectricity. This review examines cell behaviour and the potential mechanisms of electrostimulation via electroactive biomaterials in bone healing, aiming to provide new insights regarding the mechanisms of bone regeneration using electroactive biomaterials.

The translational potential of this article

This review examines the roles of electroactive biomaterials in rehabilitating the electrical microenvironment to facilitate bone regeneration, addressing current progress in electrical biomaterials and the mechanisms whereby electrical cues mediate bone regeneration. Interactions between osteogenesis-related cells and electroactive biomaterials are summarized, leading to proposals regarding the use of electrical stimulation-based therapies to accelerate bone healing.

Electroactive Biomaterials Regulate the Electrophysiological Microenvironment to Promote Bone and Cartilage Tissue Regeneration

The incidence of large bone and articular cartilage defects caused by traumatic injury is increasing worldwide; the tissue regeneration process for these injuries is lengthy due to limited self‐healing ability. Endogenous bioelectrical phenomenon has been well recognized to play an important role in bone and cartilage homeostasis and regeneration. Studies have reported that electrical stimulation (ES) can effectively regulate various biological processes and holds promise as an external intervention to enhance the synthesis of the extracellular matrix, thereby accelerating the process of bone and cartilage regeneration. Hence, electroactive biomaterials have been considered a biomimetic approach to ensure functional recovery by integrating various physiological signals, including electrical, biochemical, and mechanical signals. This review will discuss the role of endogenous bioelectricity in bone and cartilage tissue, as well as the effects of ES on cellular behaviors. Then, recent advances in electroactive materials and their applications in bone and cartilage tissue regeneration are systematically overviewed, with a focus on their advantages and disadvantages as tissue repair materials and performances in the modulation of cell fate. Finally, the significance of mimicking the electrophysiological microenvironment of target tissue is emphasized and future development challenges of electroactive biomaterials for bone and cartilage repair strategies are proposed.

Recent advances using MXenes in biomedical applications

An MXene is a novel two-dimensional transition metal carbide or nitride, with a typical formula of Mn+1XnTx (M = transition metals, X = carbon or nitrogen, and T = functional groups). MXenes have found wide application in biomedicine and biosensing, owing to their high biocompatibility, abundant reactive surface groups, good conductivity, and photothermal properties. Applications include photo- and electrochemical sensors, energy storage, and electronics. This review will highlight recent applications of MXene and MXene-derived materials in drug delivery, tissue engineering, antimicrobial activity, and biosensors (optical and electrochemical). We further elaborate on recent developments in utilizing MXenes for photothermal cancer therapy, and we explore multimodal treatments, including the integration of chemotherapeutic agents or magnetic nanoparticles for enhanced therapeutic efficacy. The high surface area and reactivity of MXenes provide an interface to respond to the changes in the environment, allowing MXene-based drug carriers to respond to changes in pH, reactive oxygen species (ROS), and electrical signals for controlled release applications. Furthermore, the conductivity of MXene enables it to provide electrical stimulation for cultured cells and endows it with photocatalytic capabilities that can be used in antibiotic applications. Wearable and in situ sensors incorporating MXenes are also included. Major challenges and future development directions of MXenes in biomedical applications are also discussed. The remarkable properties of MXenes will undoubtedly lead to their increasing use in the applications discussed here, as well as many others.

Collagen type I-based recombinant peptide promotes bone regeneration in rat critical-size calvarial defects by enhancing osteoclast activity at late stages of healing

Introduction

We recently demonstrated the bone-forming potential of medium-cross-linked recombinant collagen peptide (mRCP) in animal models of bone defects. However, these studies were limited to a 4-week observation period; therefore, in the present study, we aimed to further evaluate mRCP as a suitable bone graft material for the alveolar cleft by analyzing its bone-forming potential, osteogenic-inducing ability, and biodegradation over an extended period of 12 weeks, using a rat critical-size calvarial defect model.

Methods

Using Sprague-Dawley rats, we created critical-size calvarial defects through a surgical procedure. The defects were then filled with 3 mg of mRCP (mRCP group) or 18 mg of Cytrans® (CA) granules, which has a carbonate apatite-based composition resembling natural bone, was used as a reference material (CA group). For negative control, the defects were left untreated. Bone volume, total bone volume (bone volume including CA granules), and bone mineral density (BMD) in the defect were assessed using micro-computed tomography (μ-CT) at 0, 4, 8, and 12 weeks after implantation. Using histomorphometric analyses of hematoxylin and eosin (H&E)-stained sections, we measured the amount of newly formed bone and total newly formed bone (new bone including CA granules) in the entire defect site, as well as the amount of newly formed bone in the central side, two peripheral sides (left and right), periosteal (top) side, and dura mater (bottom) side. In addition, we measured the amount of residual bone graft material in the defect. Osteoclasts and osteoblasts in the newly formed bone were detected using tartrate-resistant acid phosphatase (TRAP) and alkaline phosphatase (ALP) staining, respectively.

Results

Bone volume in the mRCP group increased over time and was significantly larger at 8 and 12 weeks after surgery than at 4 weeks. The bone volume in the mRCP group was greater than that of the CA and control groups at 4, 8, and 12 weeks after implantation, and while the total bone volume was greater in the CA group after 4 and 8 weeks, the mRCP group had comparable levels of total bone volume to that of the CA group at 12 weeks after implantation. The BMD of the mRCP group reached similar levels to native calvaria bone at the same time point. H&E-stained sections revealed a larger amount of newly formed bone 12 weeks after implantation in the mRCP group compared to that of the CA and control groups. The total newly formed bone at 12 weeks after implantation was on par with that in the CA group. Furthermore, at the defect site, the area of newly formed bone was larger on the peripheral and dura mater sides. Notably, the number of osteoclasts in the mRCP group was higher than in the CA and control groups and peaked 8 weeks after implantation, which coincided with the timing of the greatest resorption of mRCP. Although the ALP-positive area was greater in the mRCP group compared to other groups, we did not detect any significant changes in the number of osteoblasts over time.

Conclusion

This study demonstrated the bone-forming potential of mRCP over an extended period of 12 weeks, suggesting that mRCP sufficiently resists resorption to promote bone formation through induction of osteoclast activation in the late stages of the healing period.

Effective Orthodontic Tooth Movement via an Occlusion-Activated Electromechanical Synergistic Dental Aligner

Malocclusion is a prevalent dental health problem plaguing over 56% worldwide. Mechanical orthodontic aligners render directional teeth movement extensively used for malocclusion treatment in the clinic, while mechanical regulation inefficiency prolongs the treatment course and induces adverse complications. As a noninvasive physiotherapy, an appropriate electric field plays a vital role in tissue metabolism engineering. Here, we propose an occlusion-activated electromechanical synergistic dental aligner that converts occlusal energy into a piezo-excited alternating electric field for accelerating orthodontic tooth movement. Within an 18-day intervention, significantly facilitated orthodontic results were obtained from young and aged Sprague-Dawley rats, increasing by 34% and 164% in orthodontic efficiency, respectively. The different efficiencies were attributed to age-distributed periodontal tissue status. Mechanistically, the electromechanical synergistic intervention modulated the microenvironment, enhanced osteoblast and osteoclast activity, promoted alveolar bone metabolism, and ultimately accelerated tooth movement. This work holds excellent potential for personalized and effective treatment for malocclusions, which would vastly reduce the suffering of the long orthodontic course.

Electroactive Biomaterials for Facilitating Bone Defect Repair under Pathological Conditions

Bone degeneration associated with various diseases is increasing due to rapid aging, sedentary lifestyles, and unhealthy diets. Living bone tissue has bioelectric properties critical to bone remodeling, and bone degeneration under various pathological conditions results in significant changes to these bioelectric properties. There is growing interest in utilizing biomimetic electroactive biomaterials that recapitulate the natural electrophysiological microenvironment of healthy bone tissue to promote bone repair. This review first summarizes the etiology of degenerative bone conditions associated with various diseases such as type II diabetes, osteoporosis, periodontitis, osteoarthritis, rheumatoid arthritis, osteomyelitis, and metastatic osteolysis. Next, the diverse array of natural and synthetic electroactive biomaterials with therapeutic potential are discussed. Putative mechanistic pathways by which electroactive biomaterials can mitigate bone degeneration are critically examined, including the enhancement of osteogenesis and angiogenesis, suppression of inflammation and osteoclastogenesis, as well as their anti-bacterial effects. Finally, the limited research on utilization of electroactive biomaterials in the treatment of bone degeneration associated with the aforementioned diseases are examined. Previous studies have mostly focused on using electroactive biomaterials to treat bone traumatic injuries. It is hoped that this review will encourage more research efforts on the use of electroactive biomaterials for treating degenerative bone conditions.

Progress in Gelatin as Biomaterial for Tissue Engineering

Tissue engineering has become a medical alternative in this society with an ever-increasing lifespan. Advances in the areas of technology and biomaterials have facilitated the use of engineered constructs for medical issues. This review discusses on-going concerns and the latest developments in a widely employed biomaterial in the field of tissue engineering: gelatin. Emerging techniques including 3D bioprinting and gelatin functionalization have demonstrated better mimicking of native tissue by reinforcing gelatin-based systems, among others. This breakthrough facilitates, on the one hand, the manufacturing process when it comes to practicality and cost-effectiveness, which plays a key role in the transition towards clinical application. On the other hand, it can be concluded that gelatin could be considered as one of the promising biomaterials in future trends, in which the focus might be on the detection and diagnosis of diseases rather than treatment.