Chronic diabetic wounds are characterized by persistent inflammation, defective resolution and impaired tissue regeneration, in which macrophage dysfunction and mitochondrial damage play central roles. Here, we developed a macrophage-targeted engineered mitochondrial transplantation system by coating adipose-derived stem cell (ADSC) mitochondria with triphenylphosphonium-modified konjac glucomannan (Mito-TPP-KGM). This design preserves mitochondrial membrane potential and ATP production while reducing ROS generation, and provides a mannose-rich corona for lectin receptor-related uptake. In RAW264.7 macrophages exposed to high glucose plus H2O2 or LPS, Mito-TPP-KGM is efficiently internalized, restores mitochondrial homeostasis, rebalances glycolysis and oxidative phosphorylation, and shifts inflammatory profiles toward a less inflammatory and more reparative phenotype. Engineered mitochondria also restore efferocytosis of apoptotic neutrophil-like cells and enhance the pro-angiogenic capacity of macrophage-conditioned media, thereby improving endothelial tube formation, migration and proliferation. Blocking experiments with mannan and anti-CD206/anti-DC-SIGN antibodies, together with species-specific mtDNA quantification, indicate that mannose-type lectin receptors contribute to the uptake and immunomodulatory effects of Mito-TPP-KGM. In a db/db mouse full-thickness wound model, local delivery of Mito-TPP-KGM promotes wound repair, improves histological healing, reduces oxidative damage, enhances angiogenesis, and modulates wound macrophage phenotype, leading to accelerated wound closure; these therapeutic benefits are partially attenuated by local CD206 blockade. Collectively, these findings demonstrate that polysaccharide-engineered mitochondria can reprogram diabetic wound macrophages via targeted mitochondrial transplantation, offering a promising immunometabolic strategy for chronic wound therapy.

Imbalanced inflammatory response and impaired angiogenesis are significant factors contributing to the non- healing of diabetic wounds. The susceptibility to bacterial infection further complicates the management of diabetic wounds. Here, an innovative "Tri-Act" bilayer hydrogel dressing (AlgHA-MFE/sHA-sEVsmiR) has been developed, which integrates visual monitoring of wound infection, immune regulation, and angiogenesis promotion, aiming to address the complex challenges posed by diabetic infected wounds. Utilizing the pH- responsive color-changing properties of anthocyanin-rich mulberry fruit extract (MFE), the upper layer of the hydrogel is endowed with the capability to visually monitor infections. Additionally, miR-210-3p-engineered small extracellular vesicles (sEVsmiR) are constructed and encapsulated in the lower layer hydrogel composed of Schiff base crosslinked hyaluronic acid (sHA). Regarding the therapeutic aspect, sEVsmiR is released from the hydrogel in a pH-responsive manner, thereby improving its utilization. In diabetic infected wounds, AlgHA-MFE/ sHA-sEVsmiR hydrogel exhibits effective hemostasis and antibacterial effects, while alleviating oxidative stress and endoplasmic reticulum stress in the wound area. By enhancing macrophage M2 polarization and angiogenesis, the hydrogel achieves therapeutic efficacy superior to traditional treatments. These results highlight the potential of this "Tri-Act" hydrogel to improve diabetic wound management, providing new insights into the development of novel wound dressings.

It is imperative to develop and implement newer, more effective strategies to address refractory diabetic wounds. As of now, there is currently no optimal solution for these wounds. Hypoxic human umbilical vein endothelial cells (HUVECs)-derived exosomes have been postulated to promote diabetic wound healing, however, its effect and molecular mechanism need further study. In this study, we aimed to investigate whether hypoxic exosomes enhance wound healing in diabetics. Based on our high-throughput sequencing, differentially expressed lncRNAs (including 64 upregulated lncRNAs and 94 downregulated lncRNAs) were found in hypoxic exosomes compared to normoxic exosomes. Interestingly, lncHAR1B was one of the prominently upregulated lncRNAs in hypoxic exosomes, showing a notable correlation with diabetic wound healing. More specifically, hypoxic exosomes were transmitted to surrounding cells, which resulted in a significant increase in lncHAR1B level, thereby relieving the dysfunction of endothelial cells and promoting the switch from M1 to M2 macrophages under high glucose conditions. Mechanistically, lncHAR1B directly interacted with the transcription factor basic helix-loop-helix family member e23 (BHLHE23), which subsequently led to its binding to the KLF transcription factor 4 (KLF4) and promoted KLF4 expression. In our in vivo experiments, the use of hypoxic exosomes-loaded HGM-QCS hydrogels (Gel-H-Exos) resulted in rapid wound healing compared to that of normoxic exosomes-loaded HGM-QCS hydrogels (Gel-N-Exos) and diabetic groups. Consequently, our study provides potentially novel therapeutic approaches aimed at accelerating wound healing and developing a practical exosomes delivery platform.

Bone nonunion poses an urgent clinical challenge that needs to be addressed. Recent studies have revealed that the metabolic microenvironment plays a vital role in fracture healing. Macrophages and bone marrow-derived mesenchymal stromal cells (BMSCs) are important targets for therapeutic interventions in bone fractures. Itaconate is a TCA cycle metabolite that has emerged as a potent macrophage immunomodulator that limits the inflammatory response. During osteogenic differentiation, BMSCs tend to undergo aerobic glycolysis and metabolize glucose to lactate. Copper ion (Cu2+) is an essential trace element that participates in glucose metabolism and may stimulate glycolysis in BMSCs and promote osteogenesis. In this study, we develop a 4-octyl itaconate (4-OI)@Cu@Gel nanocomposite hydrogel that can effectively deliver and release 4-OI and Cu2+ to modulate the metabolic microenvironment and improve the functions of cells involved in the fracture healing process. The findings reveal that burst release of 4-OI reduces the inflammatory response, promotes M2 macrophage polarization, and alleviates oxidative stress, while sustained release of Cu2+ stimulates BMSC glycolysis and osteogenic differentiation and enhances endothelial cell angiogenesis. Consequently, the 4-OI@Cu@Gel system achieves rapid fracture healing in mice. Thus, this study proposes a promising regenerative strategy to expedite bone fracture healing through metabolic reprogramming of macrophages and BMSCs.

The clinical role and underlying mechanisms of valproic acid (VPA) on bone homeostasis remain controversial. Herein, we confirmed that VPA treatment was associated with decreased bone mass and bone mineral density (BMD) in both patients and mice. This effect was attributed to VPA-induced elevation in osteoclast formation and activity. Through RNA-sequencing, we observed a significant rise in precursor miR-6359 expression in VPA-treated osteoclast precursors in vitro, and further, a marked upregulation of mature miR-6359 (miR-6359) in vivo was demonstrated using quantitative real-time PCR (qRT-PCR) and miR-6359 fluorescent in situ hybridization (miR-6359-FISH). Specifically, the miR-6359 was predominantly increased in osteoclast precursors and macrophages but not in neutrophils, T lymphocytes, monocytes and bone marrow-derived mesenchymal stem cells (BMSCs) following VPA stimulation, which influenced osteoclast differentiation and bone-resorptive activity. Additionally, VPA-induced miR-6359 enrichment in osteoclast precursors enhanced reactive oxygen species (ROS) production by silencing the SIRT3 protein expression, followed by activation of the MAPK signaling pathway, which enhanced osteoclast formation and activity, thereby accelerating bone loss. Currently, there are no medications that can effectively treat VPA-induced bone loss. Therefore, we constructed engineered small extracellular vesicles (E-sEVs) targeting osteoclast precursors in bone and naturally carrying anti-miR-6359 by introducing of EXOmotif (CGGGAGC) in the 3’-end of the anti-miR-6359 sequence. We confirmed that the E-sEVs exhibited decent bone/osteoclast precursor targeting and exerted protective therapeutic effects on VPA-induced bone loss, but not on ovariectomy (OVX) and glucocorticoid-induced osteoporotic models, deepening our understanding of the underlying mechanism and treatment strategies for VPA-induced bone loss.

This article has been corrected: The authors found an error in Figure 5G, which depicts transwell migration assays assessing the effects of miR-15a-3p inhibition on HUVEC cells. The central panel, illustrating migration of HUVECs treated with exosomes derived from DFU individuals (Dia-Exos), was replaced with the appropriate image from the original set of experiments. This inadvertent error does not in any way compromise the validity or integrity of the study's findings. The authors take full responsibility for this oversight and sincerely apologize for any inconvenience caused.

Chitosan (CS) and its derivatives have been applied extensively in the biomedical field owing to advantageous characteristics including biodegradability, biocompatibility, antibacterial activity and adhesive properties. The low solubility of CS at physiological pH limits its use in systems requiring higher dissolving ability and a suitable drug release rate. Besides, CS can result in fast drug release because of its high swelling degree and rapid water absorption in aqueous media. As a water-soluble derivative of CS, carboxymethyl chitosan (CMC) has certain improved properties, rendering it a more suitable candidate for wound healing, drug delivery and tissue engineering applications. This review will focus on the antibacterial, anticancer and antitumor, antioxidant and antifungal bioactivities of CMC and the most recently described applications of CMC in wound healing, drug delivery, tissue engineering, bioimaging and cosmetics.

Fracture combined with traumatic brain injury (TBI) is one of the most common and serious types of compound trauma in the clinic and is characterized by dysfunction of cellular communication in injured organs. Our prior studies found that TBI was capable of enhancing fracture healing in a paracrine manner. Exosomes (Exos), as small extracellular vesicles, are important paracrine vehicles for noncell therapy. However, whether circulating Exos derived from TBI patients (TBI-Exos) regulate the prohealing effects of fractures remains unclear. Thus, the present study aimed to explore the biological effects of TBI-Exos on fracture healing and reveal the potential molecular mechanism. TBI-Exos were isolated by ultracentrifugation, and the enriched miR-21-5 p was identified by qRT‒PCR analysis. The beneficial effects of TBI-Exos on osteoblastic differentiation and bone remodeling were determined by a series of in vitro assays. Bioinformatics analyses were conducted to identify the potential downstream mechanisms of the regulatory effect of TBI-Exos on osteoblasts. Furthermore, the role of the potential signaling pathway of TBI-Exos in mediating the osteoblastic activity of osteoblasts was assessed. Subsequently, a murine fracture model was established, and the effect of TBI-Exos on bone modeling was demonstrated in vivo. TBI-Exos can be internalized by osteoblasts, and in vitro, suppression of SMAD7 promoted osteogenic differentiation, whereas knockdown of miR-21-5 p in TBI-Exos strongly inhibited this bone-beneficial effect. Similarly, our results confirmed that preinjection of TBI-Exos led to enhanced bone formation, whereas knockdown of exosomal miR-21-5 p substantially impaired this bone-beneficial effect in vivo.

The treatment of wounds is a worldwide challenge, and wound infection can affect the effectiveness of wound treatment and further increase the disease burden. Copper is an essential trace element that has been shown to have broad-spectrum antibacterial effects and to be involved in the inflammation, proliferation, and remodeling stages of wound healing. Compared to treatments such as bioactive factors and skin grafts, copper has the advantage of being low-cost and easily available, and has received a lot of attention in wound healing. Recently, biomaterials made by incorporating copper into bioactive glasses, polymeric scaffolds and hydrogels have been used to promote wound healing by the release of copper ions. In addition, copper-incorporated biomaterials with catalytic, photothermal, and photosensitive properties can also accelerate wound healing through antibacterial and wound microenvironment regulation. This review summarizes the antibacterial mechanisms of copper- incorporated biomaterials and their roles in wound healing, and discusses the current challenges. A comprehensive understanding of the role of copper in wounds will help to facilitate new preclinical and clinical studies, thus leading to the development of novel therapeutic tools.

Due to the low incidence of posteromedial tibial plateau fractures and limited clinical data available, the optimal treatment for this type of fracture remains to be established. This type of fracture, also known as Hoffa-like fracture of the tibial plateau, shares a similar mechanism of injury with the Hoffa fracture of the femoral condyle. In the field of orthopedics, finite element analysis is considered a valuable method to guide clinical decision-making. In this study, four methods used for internal fixation of Hoffa-like fractures of the tibial plateau were compared using computer simulation and applying a finite element method (FEM). The methods compared were lateral L-plate fixation alone (Model A); lateral L-plate combined with posterior anti-slip plate (reconstruction plate/T-plate) fixation (Model B); lateral L-plate combined with posterior hollow nail fixation of the fracture block (Model C); and lateral L-plate combined with anterior hollow nail fixation of the fracture (Model D). The maximum displacement of the model and the maximum stress of the internal fixation material were analyzed by applying an axial load of 2,500 N. The results showed that, in the normal bone model, the maximum displacement of the fracture in Model A was 0.60032 mm, with improved stability through the addition of posterior lateral plate fixation in Model B and reduction of the displacement to 0.38882 mm. The maximum displacement in Model C and Model D was comparable, amounting to 0.42345 mm and 0.42273 mm, respectively. Maximum stress was 1235.6 MPa for Model A, 84.724 MPa for Model B, 99.805 MPa for Model C, and 103.19 MPa for Model D. In the internal fixation analysis of the osteoporotic fracture model, we observed patterns similar to the results of the normal bone model. The results indicated that Model B yielded the overall best results in the treatment of Hoffa-like fractures of the tibial plateau. The orthopedic surgeon may wish to implement these insights into the perioperative algorithm, thereby refining and optimizing clinical patient care. In addition, our findings pave the way for future research efforts.

Musculoskeletal disorders (MSDs), which include a range of pathologies affecting bones, cartilage, muscles, tendons, and ligaments, account for a significant portion of the global burden of disease. While pharmaceutical and surgical interventions represent conventional approaches for treating MSDs, their efficacy is constrained and frequently accompanied by adverse reactions. Considering the rising incidence of MSDs, there is an urgent demand for effective treatment modalities to alter the current landscape. Phototherapy, as a controllable and non-invasive technique, has been shown to directly regulate bone, cartilage, and muscle regeneration by modulating cellular behavior. Moreover, phototherapy presents controlled ablation of tumor cells, bacteria, and aberrantly activated inflammatory cells, demonstrating therapeutic potential in conditions such as bone tumors, bone infection, and arthritis. By constructing light-responsive nanosystems, controlled drug delivery can be achieved to enable precise treatment of MSDs. Notably, various phototherapy nanoplatforms with integrated imaging capabilities have been utilized for early diagnosis, guided therapy, and prognostic assessment of MSDs, further improving the management of these disorders. This review provides a comprehensive overview of the strategies and recent advances in the application of phototherapy for the treatment of MSDs, discusses the challenges and prospects of phototherapy, and aims to promote further research and application of phototherapy techniques.

The treatment of diabetic wounds remains a major challenge in clinical practice, with chronic wounds characterized by multiple drug-resistant bacterial infections, angiopathy, and oxidative damage to the microenvironment. Herein, a novel in situ injectable HA@MnO2 /FGF-2/Exos hydrogel is introduced for improving diabetic wound healing. Through a simple local injection, this hydrogel is able to form a protective barrier covering the wound, providing rapid hemostasis and long-term antibacterial protection. The MnO2 /ε-PL nanosheet is able to catalyze the excess H2 O2 produced in the wound, converting it to O2 , thus not only eliminating the harmful effects of H2 O2 but also providing O2 for wound healing. Moreover, the release of M2-derived Exosomes (M2 Exos) and FGF-2 growth factor stimulates angiogenesis and epithelization, respectively. These in vivo and in vitro results demonstrate accelerated healing of diabetic wounds with the use of the HA@MnO2 /FGF-2/Exos hydrogel, presenting a viable strategy for chronic diabetic wound repair.

Chronic refractory wound (CRW) is one of the most challengeable issues in clinic due to complex pathogenesis, long course of disease and poor prognosis. Experts need to conduct systematic summary for the diagnosis and treatment of CRW due to complex pathogenesis and poor prognosis, and standard guidelines for the diagnosis and treatment of CRW should be created. The Guideline forthe diagnosis and treatment of chronic refractory wounds in orthopedic trauma patients ( version 2023) was created by the expert group organized by the Chinese Association of Orthopedic Surgeons, Chinese Orthopedic Association, Chinese Society of Traumatology, and Trauma Orthopedics and Multiple Traumatology Group of Emergency Resuscitation Committee of Chinese Medical Doctor Association after the clinical problems were chosen based on demand-driven principles and principles of evidence-based medicine. The guideline systematically elaborated CRW from aspects of the epidemiology, diagnosis, treatment, postoperative management, complication prevention and comorbidity management, and rehabilitation and health education, and 9 recommendations were finally proposed to provide a reliable clinical reference for the diagnosis and treatment of CRW.

Bone mesenchymal stem cells (BMSCs) play an important role in maintaining the dynamic balance of bone metabolism. Recent studies have reported that a decrease in the osteogenic function of MSCs is strongly associated with osteoporosis. Melatonin is a neuroendocrine hormone produced in the pineal gland and is essential in the physiological regulation. This study is aimed at exploring the effect of melatonin on MSCs osteoblastic differentiation and elucidate the underlying mechanisms. We isolated BMSCs from rat bone marrow and demonstrated that melatonin improved osteogenic differentiation of BMSCs by the alizarin red staining and ALP staining. We then showed that melatonin enhanced osteogenic gene expression in BMSCs, including ALP, Col 1, OCN, OPN, and RUNX2. We further revealed that melatonin inhibited the inflammatory response of BMSCs by suppressing the NF-κB signaling pathways. In light of this, we found that the NF-κB pathway-specific activator TNF-α activated the NF-κB pathway, inhibited osteogenic differentiation, and induced inflammatory response in BMSCs. Melatonin was found to reverse the inhibitory effect of TNF-α on osteogenic differentiation and inflammation in BMSCs. Taken together, these findings indicated that melatonin may have therapeutic potential to be used for the treatment of osteoporosis.

Background Postmenopausal bone loss, mainly caused by excessive bone resorption mediated by osteoclasts, has become a global public health burden. Metformin, a hypoglycemic drug, has been reported to have beneficial effects on maintaining bone health. However, the role and underlying mechanism of metformin in ovariectomized (OVX)-induced bone loss is still vague. Results In this study, we demonstrated for the first time that metformin administration alleviated bone loss in postmenopausal women and ovariectomized mice, based on reduced bone resorption markers, increased bone mineral density (BMD) and improvement of bone microstructure. Then, osteoclast precursors administered metformin in vitro and in vivo were collected to examine the differentiation potential and autophagical level. The mechanism was investigated by infection with lentivirus-mediated BNIP3 or E2F1 overexpression. We observed a dramatical inhibition of autophagosome synthesis and osteoclast formation and activity. Treatment with RAPA, an autophagy activator, abrogated the metformin-mediated autophagy downregulation and inhibition of osteoclastogenesis. Additionally, overexpression of E2F1 demonstrated that reduction of OVX-upregulated autophagy mediated by metformin was E2F1 dependent. Mechanistically, metformin-mediated downregulation of E2F1 in ovariectomized mice could downregulate BECN1 and BNIP3 levels, which subsequently perturbed the binding of BECN1 to BCL2. Furthermore, the disconnect between BECN1 and BCL2 was shown by BNIP3 overexpression. Conclusion In summary, we demonstrated the effect and underlying mechanism of metformin on OVX-induced bone loss, which could be, at least in part, ascribed to its role in downregulating autophagy during osteoclastogenesis via E2F1-dependent BECN1 and BCL2 downregulation, suggesting that metformin or E2F1 inhibitor is a potential agent against postmenopausal bone loss.

Although the immune system is well recognized as a key player in fracture repair, the exact mechanisms, particularly the role of regulatory T-cells (Tregs), have not yet been established. Our increased understanding of the Tregs and exosomes involved in organ repair creates opportunity of application of Tregs derived Exosomes (TregD-Exos) in the modulation of fracture repair. In the present study, we report that TregD-Exos containing miR-142-3p can be shuttled into bone mesenchymal stem cells (BMSCs) and Human umbilical vein endothelial cells (HUVECs) promoting osteogenesis and angiogenesis. Overexpression of miR-142-3p remarkedly promoted BMSC osteoblastic differentiation, and enhanced HUVEC function, including proliferation, migration and angiogenesis. Furthermore, TGFBR1/SMAD2 was shown to be involved in the TregD-Exos’ promotive effect on bone healing. Moreover, both TregD-Exos and miR-142-3p administration restored bone repair in vivo. Taken together, our results indicate that TregD-Exos containing miR-142-3p can be transferred to BMSCs and HUVECs with robust effects on osteogenesis and angiogenesis. These findings shed a new light for the use of Tregs in facilitating bone repair, suggesting that both TregD-Exos and miR-142-3p are promising effective therapeutic agents for bone remodeling.

Diabetic wounds remain a great challenge for clinicians due to the multiple bacterial infections and oxidative damage. Exosomes, as an appealing nanodrug delivery system, have been widely applied in the treatment of diabetic wounds. Endovascular cells are important component cells of the vascular wall. Herein, we investigated the effects of HUCMSCs and HUC-Exos (exosomes secreted by HUCMSCs) on diabetic wound healing. In this study, HUVECs were coincubated with HUCMSCs, and HUC-Exos were utilized for in vitro and in vivo experiments to verify their roles in the regulation of diabetic wound healing. Our results demonstrated that HUCMSCs have the ability to regulate oxidative stress injuries of endothelial cells through exosomes and accelerate diabetic cutaneous wound healing in vitro. The present study suggests that HUC-Exos accelerate diabetic cutaneous wound healing, providing a promising therapeutic strategy for chronic diabetic wound repair.

BACKGROUND:Diabetic foot ulcer (DFU), persistent hyperglycemia and inflammation, together with impaired nutrient and oxygen deficiency, can present abnormal angiogenesis following tissue injury such that these tissues fail to heal properly. It is critical to design a new treatment method for DFU patients with a distinct biomechanism that is more effective than current treatment regimens.METHOD:Graphene oxide (GO) was combined with a biocompatible polymer as a kind of modified GO-based hydrogel. The characterization of our biomaterial was measured in vitro. The repair efficiency of the biomaterial was evaluated in the mouse full-skin defect models. The key axis related to diabetic wound (DW) was identified and investigated using bioinformatics analyses and practical experiments.RESULT:In the study, we found that our modified GO-based wound dressing material is a promising option for diabetic wound. Secondly, our biomaterial could enhance the secretion of small EVs (sEVs) with more miR-21 by adipose-derived mesenchymal stem cells (AD-MSCs). Thirdly, the PVT1/PTEN/IL-17 axis was found to be decreased to promote DFU wound healing by modifying miR-21 with the discovery of PVT1 as a critical LncRNA by bioinformatics analysis and tests.CONCLUSION:These findings could aid in the development of clinical care strategies for DFU wounds.

Peroxidase-like activity of artificial enzymes has been widely used for biosensing. However, the peroxidase-like activity of artificial enzymes is far from satisfactory in contrast to natural enzymes. Herein, by imitating the structure of natural enzymes, we propose a one-pot annealing process to prepare imidazole ring-doped graphitic carbon nitride with enhanced peroxidase-like activity. By adding histidine during calcination, the graphite-phase carbon nitride doped with imidazole rings (g-C3N4-His) is obtained, which shows enhanced peroxidase-like activity by 46.5 times compared to bare g-C3N4. Furthermore, imidazole rings from g-C3N4-His make it possible to anchor Cu (II) active sites on it to produce g-C3N4-His-Cu, which show another 3 times increased peroxidase-like activity. It should be noted that the as-prepared g-C3N4-His-Cu could work in wide pH (4-9) and low temperature (5 oC) conditions. The ultrahigh peroxidase-like activity is attributed to the electronic effect of imidazole rings and active sites of Cu (II) for ·OH production. Based on the enhanced peroxidase-like activity, a H2O2 and glucose biosensor is developed with high sensitivity (limit of detection 10 nM). The results show that the g-C3N4-His-Cu has high selectivity and sensitivity for glucose detection in urea of diabetic patients. Therefore, the biosensor shows potential applications in diabetic diagnosis in clinic.