Bone-Targeted Biomimetic Nanogels Re-Establish Osteoblast/Osteoclast Balance to Treat Postmenopausal Osteoporosis.

Insufficient bone formation and excessive bone resorption caused by estrogen deficiency are the major factors resulting in the incidence of postmenopausal osteoporosis (PMOP). The existing drugs usually fail to re-establish the osteoblast/osteoclast balance from both sides and generate side-effects owing to the lack of bone-targeting ability. Here, engineered cell-membrane-coated nanogels PNG@mR&C capable of scavenging receptor activator of nuclear factor-κB ligand (RANKL) and responsively releasing therapeutic PTH 1-34 in the bone microenvironment are prepared from RANK and CXCR4 overexpressed bone mesenchymal stem cell (BMSC) membrane-coated chitosan biopolymers. The CXCR4 on the coated-membranes confer bone-targeting ability, and abundant RANK effectively absorb RANKL to inhibit osteoclastogenesis. Meanwhile, the release of PTH 1-34 triggered by osteoclast-mediated acid microenvironment promote osteogenesis. In addition, the dose and frequency are greatly reduced due to the smart release property, prolonged circulation time, and bone-specific accumulation. Thus, PNG@mR&C exhibits satisfactory therapeutic effects in the ovariectomized (OVX) mouse model. This study provides a new paradigm re-establishing the bone metabolic homeostasis from multitargets and shows great promise for the treatment of PMOP.

Ångstrom-scale gold particles loaded with alendronate via alpha-lipoic acid alleviate bone loss in osteoporotic mice.

Osteoporosis is a highly prevalent metabolic disease characterized by low systemic bone mass and deterioration of bone microarchitecture, resulting in reduced bone strength and increased fracture risk. Current treatment options for osteoporosis are limited by factors such as efficacy, cost, availability, side effects, and acceptability to patients. Gold nanoparticles show promise as an emerging osteoporosis therapy due to their osteogenic effects and ability to allow therapeutic delivery but have inherent constraints, such as low specificity and the potential for heavy metal accumulation in the body. This study reports the synthesis of ultrasmall gold particles almost reaching the Ångstrom (Ång) dimension. The antioxidant alpha-lipoic acid (LA) is used as a dispersant and stabilizer to coat Ångstrom-scale gold particles (AuÅPs). Alendronate (AL), an amino-bisphosphonate commonly used in drug therapy for osteoporosis, is conjugated through LA to the surface of AuÅPs, allowing targeted delivery to bone and enhancing antiresorptive therapeutic effects. In this study, alendronate-loaded Ångstrom-scale gold particles (AuÅPs-AL) were used for the first time to promote osteogenesis and alleviate bone loss through regulation of the WNT signaling pathway, as shown through in vitro tests. The in vivo therapeutic effects of AuÅPs-AL were demonstrated in an established osteoporosis mouse model. The results of Micro-computed Tomography, histology, and tartrate-resistant acid phosphatase staining indicated that AuÅPs-AL significantly improved bone density and prevented bone loss, with no evidence of nanoparticle-associated toxicity. These findings suggest the possible future application of AuÅPs-AL in osteoporosis therapy and point to the potential of developing new approaches for treating metabolic bone diseases using Ångstrom-scale gold particles.

Lateral locking plate plus antero-posterior lag screws techniques for the management of posterolateral tibial plateau fracture: preliminary clinical results and biomechanical study.

INTRODUCTION: To date, there is no consensus on the optimal surgical strategy for the treatment of posterolateral tibial plateau fracture (PLF). This study introduced a novel, simple technique for treating PLF with a lateral locking plate plus antero-posterior lag screws (LPpLS). METHODS: We conducted a retrospective case series of 42 patients (Female/Male 19/23) with PLF treated with LPpLS between 1 July 2016 and 30 June 2019. Several pre- and postoperative outcomes were recorded, including operative time, intraoperative blood loss, CT findings, HSS, and ROM. For biomechanical studies, seventy synthetic tibiae with a simulated posterolateral split fracture were divided into seven groups. The biomechanical evaluation included displacement measurement at axial compression and fatigue testing. RESULTS: Forty-two eligible patients were followed up for an average of 18 months (range 14-21 months). Postoperative radiographs and CT showed good positioning of plates and screws, no fracture fragment loss, and normal articular surfaces in all 42 cases. The biomechanical study showed that the axial stiffness of LPpLS was in the same fashion as the posterior buttress plate and better than the other fixation methods (P < 0.05). Additionally, the LPpLS group had a smaller displacement of fracture fragments along the X-axis (medial to lateral direction) than the BP group (P < 0.01). CONCLUSIONS: The LPpLS technique could implement good reconstruction of the PLF, showing satisfactory therapeutic effect. The biomechanical evaluation demonstrated that the LPpLS had better stability in three-dimensional directions for PLF than other fixation strategies.

Conversion from Spanning External Fixation to Open Reduction Internal Fixation Contributes to Healing of Soft Tissues and Fractures in Open Distal Humeral Fractures.

BACKGROUND Open distal humeral fractures (DHFs) often lead to loss of elbow function, thereby seriously affecting patient quality of life. The aim of this study was to evaluate the treatment outcomes of 2 surgical techniques to determine the better method for repairing open DHFs. Both groups were treated with immediate debridement first, and then group I had only internal fixation (IF), while group II underwent initial external fixation (EF) followed by IF surgery. MATERIAL AND METHODS This retrospective study included 32 patients who had open DHFs between 2013 and 2018. Twelve patients underwent thorough debridement and temporary EF treatment and converted to IF as the ultimate treatment. Twenty patients were treated with immediate open reduction and internal fixation (ORIF). Data of final treatment outcomes were analyzed at the latest follow-up. A comparative analysis of radiological results, function observations, and complications was performed for the 2 surgical groups. RESULTS All DHFs and osteotomized olecranon united after a mean of 5.2±1.21 months. No significant differences were observed in other preoperative demographic data between the 2 groups. Moreover, there was no significant difference in postoperative complications, elbow range of motion, or fracture healing time between the 2 groups. CONCLUSIONS The evidence provided by our study highlights the efficacy of definitive IF in treating open DHFs, which is recommended whenever possible. Furthermore, the combination of EF and ORIF, according to the type of soft tissue damage, may be a promising treatment option with a low revision rate for patients with open DHFs.

The mechanism by which enoxaparin sodium-high-viscosity bone cement reduces thrombosis by regulating CD40 expression in endothelial cells.

OBJECTIVE: PMMA bone cement leads to the development of local thrombi. Our study found that ES-PMMA bone cement, a novel material, can reduce local thrombosis. We used a simple and reproducible animal model to confirm the reduction in local thrombosis and preliminarily explored the associated molecular mechanism. METHODS: New Zealand rabbits, which were used to model thrombosis using extracorporeal carotid artery shunts, were divided into the following three groups, with 10 rabbits in each group: the sham group, PMMA group and ES-PMMA group. Four hours after modelling, experimental samples were collected, and the degree of thrombosis was compared between the groups. The expression of thrombomodulin in endothelial cells was quantified in vascular tissues samples. RESULTS: Thrombosis was observed in the PMMA group and ES-PMMA group but not in the sham group. The thrombosis weight was 0.00732 ± 0.00089 g/cm in the PMMA group and 0.00554 ± 0.00077 g/cm in the ES-PMMA group (P < 0.001). Quantitative real-time polymerase chain reaction (RT-qPCR) and Western blotting revealed that the expression of CD40, which can regulate thrombosis in vascular endothelial cells, was significantly lower in the ES-PMMA group than in the PMMA group. CONCLUSION: Compared with PMMA bone cement, ES-PMMA bone cement can reduce local thrombosis by decreasing the expression of the thrombus-associated regulatory protein CD40 in vascular endothelial cells.

Remote-controllable bone-targeted delivery of estradiol for the treatment of ovariectomy-induced osteoporosis in rats.

BACKGROUND: Osteoporosis (OP) is a systemic skeletal disease marked by bone mass reduction and bone tissue destruction. Hormone replacement therapy is an effective treatment for post-menopausal OP, but estrogen has poor tissue selectivity and severe side effects. RESULTS: In this study, we constructed a poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs)-based drug delivery system to co-load 17ß estradiol (E2) and iron oxide (Fe3O4) together, modified with alendronate (AL) to achieve bone targeting and realize a magnetically remote-controllable drug release. The NPs were fabricated through the emulsion solvent diffusion method. The particle size was approximately 200 nm while the encapsulation efficiency of E2 was 58.34 ± 9.21%. The NPs were found to be spherical with a homogenous distribution of particle size. The NPs showed good stability, good biocompatibility, high encapsulation ability of E2 and excellent magnetic properties. The NPs could be effectively taken up by Raw 264.7 cells and were effective in enriching drugs in bone tissue. The co-loaded NPs exposed to an external magnetic field ameliorated OVX-induced bone loss through increased BV/TV, decreased Tb.N and Tb.Sp, improved bone strength, increased PINP and OC, and downregulated CTX and TRAP-5b. The haematological index and histopathological analyses displayed the NPs had less side effects on non-skeletal tissues. CONCLUSIONS: This study presented a remote-controlled release system based on bone-targeted multifunctional NPs and a new potential approach to bone-targeted therapy of OP.

Customized treatment protocols for patients with closed fracture in hospitals at varying coronavirus disease 2019 (COVID-19) risk.

BACKGROUND: To determine an optimized treatment protocol during the COVID-19 epidemic for patients with closed fracture and delayed surgery. METHODS: The epidemic data of three hospitals, randomly selected from different administrative regions of Wuhan, were analyzed retrospectively from 23 January to 31 March 2020. Changes in the number of confirmed cases per day (cumulative and new) of each region were tracked as a reflection of changing epidemic risk levels. The risk level map was drawn. The epidemic status, treatment protocols, and treatment efficiencies for patients with closed fracture in the three hospitals were compared. RESULTS: Overall, 138 patients with closed fracture were admitted. Each hospital had established its own protocol, according to the initial perceived risk. Based on the risk level map, over the study period, the risk levels of the three regions changed independently and were not in sync. All patients recovered and were timely discharged. No staff member was detected with COVID-19. CONCLUSIONS: The COVID-19 risk level of each area is dynamic. To optimize medical resources, avoid cross-infection, and improve efficiency, changes in epidemic risk should be monitored. For patients with closed fracture, treatment protocols should be adjusted according to changes in epidemic risk.

Long non-coding RNA BDNF-AS modulates osteogenic differentiation of bone marrow-derived mesenchymal stem cells.

For patients with osteoporosis, the inability of osteogenic differentiation is the key reason for bone loss. In this study, we investigated the expression and function of long non-coding RNA BDNF-AS in mesenchymal stem cell-derived osteogenic differentiation. Mouse bone marrow-derived mesenchymal stem cells (BMMSCs) were cultured in vitro and induced toward osteogenic differentiation. Quantitative real-time PCR (qRT-PCR) was used to evaluate gene expressions of BDNF-AS and BDNF during osteogenic differentiation. BMMSCs were also extracted from ovariectomized (OVX) mice. The dynamic change of BDNF-AS in OVX-derived BMMSCs during osteogenic differentiation was also evaluated. Lentivirus was used to upregulate BDNF-AS in BMMSCs. The effects of BDNF-AS upregulation on BMMSCs' proliferation and osteogenic differentiation were then evaluated. In addition, qRT-PCR and western blot were applied to further examine the effect of BDNF-AS upregulation on osteogenesis-associated signaling pathways, including BDNF, OPN, and Runx2, in osteogenic differentiation. BDNF-AS was downregulated, whereas BDNF was upregulated in osteogenic differentiation of BMMSCs. Among OVX-derived BMMSCs, BDNF-AS expression was upregulated during osteogenic differentiation. Lentivirus-induced BDNF-AS upregulation promoted BMMSCs self-proliferation but inhibited osteogenic differentiation, as demonstrated by proliferation, alizarin red staining, and alkaline phosphatase activity assays, respectively. QRT-PCR and western blot demonstrated that BDNF, OPN, and Runx2 were downregulated by BDNF-AS upregulation in the differentiated BMMSCs. BDNF-AS is dynamically regulated in osteogenic differentiation. Upregulating BDNF-AS inhibits osteogenesis, possibly through inverse regulation on BDNF and osteogenic signaling pathways.

Surgical management of delayed irreducible Gartland III supracondylar fractures in children: open reduction and internal fixation versus external fixation.

BACKGROUND: Percutaneous pinning has been accepted as the "gold standard" for displaced supracondylar humeral fracture (SHF) in children. However, to secure an anatomic reduction and to reduce the rotated fragment, open reduction is often necessary when there is inadequate stabilization or a satisfactory reduction has failed to be achieved. The study aimed to compare the efficacy of the open reduction and bioabsorbable poly-d,l-lactic acid (PDLLA) pin fixation method with the closed reduction and lateral external fixation method in irreducible delayed Gartland type III SHF in children. METHODS: In this study, 124 consecutive patients with irreducible delayed Gartland type III SHF were included between 2005 and 2013. Two different surgical methods were performed in patients separately. Group I had 64 patients undergoing bioabsorbable PDLLA pin fixation after open reduction, whereas group II had 60 patients treated by lateral external fixation after closed reduction. The outcome of treatment was evaluated by the Mayo Elbow Performance Score and the criteria of Flynn. RESULTS: Operation duration was longer in group I than in group II. Scoring of function showed that all patients had satisfactory results in both groups. The cosmetic result was satisfactory in all patients except 1 in group I. CONCLUSIONS: Both bioabsorbable PDLLA pin fixation and lateral external fixation are reliable, safe treatment alternatives for irreducible delayed SHF. Neither open nor closed reduction is linked to an increased rate of perioperative complications or unsatisfactory functional results.

Surfactant-free poly(lactide-co-glycolide) nanoparticles for improving in vitro anticancer efficacy of tetrandrine.

The objective of this study was to improve the efficacy of a natural compound tetrandrine against cancer by designing surfactant-free poly(lactic-co-glycolic acid) (PLGA) nanoparticles as drug carriers for tetrandrine. Nanoparticles were prepared from PLGA via the nano-precipitation method with or without the presence of surfactant poly(vinyl alcohol) (PVA) to encapsulate tetrandrine. Tetrandrine-loaded surfactant-free PLGA nanoparticles had an average particle size of 169.3 nm and morphology similar to the PLGA nanoparticles prepared using PVA as the surfactant. Tetrandrine-loaded surfactant-free PLGA nanoparticles could retard drug release in phosphate buffered saline (PBS) at pH 7.4 and the cumulative release of tetrandrine reached up to 68.33% over a period of 120 h. A549 cell line was used as the model cancer cells to investigate anticancer capability of tetrandrine-loaded surfactant-free PLGA nanoparticles via apoptosis assay, cytotoxicity and lysosome injury studies. The results showed that tetrandrine-loaded surfactant-free PLGA nanoparticles could effectively reduce cell viability and synergistically enhance tetrandrine-induced cell apoptosis.

The effects of mPEG proportion and LA/GA ratio on degradation and drug release behaviors of PLGA-mPEG microparticles.

The purpose of this research was to evaluate the effects of mPEG proportion and LA/GA ratio on degradation and release behavior of PLGA-mPEG microparticles prepared by the emulsion evaporation method. Mometasone furoate was employed as model drug and encapsulated into five types of PLGA-mPEG microparticles in the same molecular weight (Mw), but different in mPEG proportion or LA/GA ratio. All types of PLGA-mPEG microparticles showed similar drug encapsulation efficiency and particle mean size, but PLGA-mPEG microparticles with higher mPEG proportion showed a faster Mw reduction rate, mass loss rate and size decrease rate according to the in vitro degradation experiment, and also, a faster drug release rate according to the in vitro release experiment. On the other hand, higher LA/GA ratio in PLGA chain of PLGA-mPEG causes a slower Mw reduction rate, mass loss rate, size decrease rate, and thus, a slower drug release rate.

Comparison of the outcomes of cannulated screws vs. modified tension band wiring fixation techniques in the management of mildly displaced patellar fractures.

BACKGROUND: K wire fixation with tension band wiring has conventionally been used for the open reduction and internal fixation of the patella. However, it suffers from distinct disadvantages such as implant irritation, need for open reduction, incidence of palpable implants, and need for subsequent implant removal. A smaller incision with percutaneous fixation may be an alternative to this established conventional technique. Thus, the purpose of this trial was to compare the treatment outcomes of patients with mildly displaced patellar fractures treated with closed reduction and percutaneous cannulated screw fixation (CRCF) as compared to open reduction and tension band wiring fixation (ORTF). Specifically, we aimed to determine whether cannulated screw fixation was associated with improved clinical outcomes at 12 months as measured using the Lysholm score, pain scores, degree of flexion, range of motion, time to radiographic union, radiographic outcomes, and complication rates. METHODS: Sixty-three patients with transverse patellar fractures displaced less than 8 mm were included in this prospective, randomized, controlled trial, with 52 patients in the final data analysis. Thirty-two patients were operatively treated by CRCF with either two or three cannulated screws. Thirty-one patients were operatively treated by conventional ORTF using the modified tension band technique. At postoperative intervals of 3, 6, and 12 months, knee function was evaluated using the Lysholm score, pain was assessed using the visual analog scale (VAS) score, and active knee extensions and flexion were measured in degrees by goniometry. RESULTS: The CRCF group had average Lysholm scores of 84.4 ± 5.8, 86.7 ± 6.4, and 93.2 ± 5.3 after 3, 6, and 12 months, respectively, which were significantly greater than those of the ORTF group (79.0 ± 5.3, p = 0.001; 81.5 ± 4.6, p = 0.002; and 89.8 ± 6.2, p = 0.039, respectively). Lower pain and squatting scores were the main reasons for the poorer Lysholm scores in the ORTF group. The VAS scores showed that the CRCF group had lower pain scores and better flexion and total range of motion (ROM) compared with the ORTF group after 3 and 6 months, although both groups had similar outcomes after 12 months. The mean fracture healing time of 2.65 months was similar in the CRCF groups (2.77 months; p = 0.440). Complication rates were 3/26 (11.5 %) in the CRCF group and 14/26 (53.4 %) in the ORTF group. Two patients in the CRCF group and eight patients in the ORTF group experienced skin irritation. In addition, two (7.7 %) patients in the CRCF group and 11 (42.3 %) patients in the ORTF group required implant removal because of symptoms due to the presence of the implants. CONCLUSION: Surgical treatment of mild displaced (less than 8 mm) transverse patellar fractures by the CRCF technique provides satisfactory clinical results and excellent knee function, with little pain and a low incidence of complications at early follow-up (up to 6 months). These results suggest that the CRCF technique may be a superior alternative to conventional ORTF. Registration Trial (Chinese Clinical Trial Register): Current Controlled Trials ChiCTR-PRCH-14005017, registration dates 2014-06-14.

Minimally invasive plate osteosynthesis with a locking compression plate is superior to open reduction and internal fixation in the management of the proximal humerus fractures.

BACKGROUND: The use of minimally invasive plate osteosynthesis (MIPO) via anterolateral deltoid splitting has good outcomes in the management of proximal humerus fractures. While using this approach has several advantages, including minimal soft tissue disruption, preservation of natural biology and minimal blood loss, there is an increased risk for axillary nerve damage. This study compared the advantages and clinical and radiological outcomes of MIPO or open reduction and internal fixation (ORIF) in patients with proximal humerus fractures. METHODS: A matched-pair analysis was performed, and patient groups were matched according to age (±3 years), sex and fracture type. Forty-three pairs of patients (average age: MIPO, 63 and ORIF, 61) with a minimum follow-up of 12 months were enrolled in the study group. The patients were investigated radiographically and clinically using the Constant score. RESULTS: The MIPO technique required less surgery time and caused less blood loss compared to ORIF (p < 0.01). In addition, MIPO required a smaller incision, resulted in less scarring, and was cosmetically more appealing and acceptable to female patients than ORIF. Following MIPO, patients had better functional results at 3 and 6 months, with better outcomes, less pain, higher satisfaction in activities of daily living, and a higher range of motion when compared to ORIF (p < 0.05). Fracture configuration, according to the AO/ASIF(Association for the Study of Internal Fixation) fracture classification, did not significantly influence the functional results. The complication rate was comparable between both groups. CONCLUSION: The use of MIPO with a locking compression plate in the management of proximal humerus fractures is a safe and superior option compared to ORIF.

Identification of specific markers for human pluripotent stem cell-derived small extracellular vesicles.

Pluripotent stem cell-derived small extracellular vesicles (PSC-sEVs) have demonstrated great clinical translational potential in multiple aging-related degenerative diseases. Characterizing the PSC-sEVs is crucial for their clinical applications. However, the specific marker pattern of PSC-sEVs remains unknown. Here, the sEVs derived from two typical types of PSCs including induced pluripotent stem cells (iPSC-sEVs) and embryonic stem cells (ESC-sEVs) were analysed using proteomic analysis by liquid chromatography with tandem mass spectrometry (LC-MS/MS), and surface marker phenotyping analysis by nanoparticle flow cytometry (NanoFCM). A group of pluripotency-related proteins were found to be enriched in PSC-sEVs by LC-MS/MS and then validated by Western Blot analysis. To investigate whether these proteins were specifically expressed in PSC-sEVs, sEVs derived from seven types of non-PSCs (non-PSC-sEVs) were adopted for analysis. The results showed that PODXL, OCT4, Dnmt3a, and LIN28A were specifically enriched in PSC-sEVs but not in non-PSC-sEVs. Then, commonly used surface antigens for PSC identification (SSEA4, Tra-1-60 and Tra-1-81) and PODXL were gauged at single-particle resolution by NanoFCM for surface marker identification. The results showed that the positive rates of PODXL (>50%) and SSEA4 (>70%) in PSC-sEVs were much higher than those in non-PSC-sEVs (<10%). These results were further verified with samples purified by density gradient ultracentrifugation. Taken together, this study for the first time identified a cohort of specific markers for PSC-sEVs, among which PODXL, OCT4, Dnmt3a and LIN28A can be detected with Western Blot analysis, and PODXL and SSEA4 can be detected with NanoFCM analysis. The application of these specific markers for PSC-sEVs identification may advance the clinical translation of PSCs-sEVs.

Application of dental pulp stem cells for bone regeneration.

Bone defects resulting from severe trauma, tumors, inflammation, and other factors are increasingly prevalent. Stem cell-based therapies have emerged as a promising alternative. Dental pulp stem cells (DPSCs), sourced from dental pulp, have garnered significant attention owing to their ready accessibility and minimal collection-associated risks. Ongoing investigations into DPSCs have revealed their potential to undergo osteogenic differentiation and their capacity to secrete a diverse array of ontogenetic components, such as extracellular vesicles and cell lysates. This comprehensive review article aims to provide an in-depth analysis of DPSCs and their secretory components, emphasizing extraction techniques and utilization while elucidating the intricate mechanisms governing bone regeneration. Furthermore, we explore the merits and demerits of cell and cell-free therapeutic modalities, as well as discuss the potential prospects, opportunities, and inherent challenges associated with DPSC therapy and cell-free therapies in the context of bone regeneration.

Local Spinal Cord Injury Treatment Using a Dental Pulp Stem Cell Encapsulated H2S Releasing Multifunctional Injectable Hydrogel.

Spinal cord injury (SCI) commonly induces nerve damage and nerve cell degeneration. In this work, a novel dental pulp stem cells (DPSCs) encapsulated thermoresponsive injectable hydrogel with sustained hydrogen sulfide (H2S) delivery is demonstrated for SCI repair. For controlled and sustained H2S gas therapy, a clinically tested H2S donor (JK) loaded octysilane functionalized mesoporous silica nanoparticles (OMSNs) are incorporated into the thermosensitive hydrogel made from Pluronic F127 (PF-127). The JK-loaded functionalized MSNs (OMSF@JK) promote preferential M2-like polarization of macrophages and neuronal differentiation of DPSCs in vitro. OMSF@JK incorporated PF-127 injectable hydrogel (PF-OMSF@JK) has a soft consistency similar to that of the human spinal cord and thus, shows a high cytocompatibility with DPSCs. The cross-sectional micromorphology of the hydrogel shows a continuous porous structure. Last, the PF-OMSF@JK composite hydrogel considerably improves the in vivo SCI regeneration in Sprague-Dawley rats through a reduction in inflammation and neuronal differentiation of the incorporated stem cells as confirmed using western blotting and immunohistochemistry. The highly encouraging in vivo results prove that this novel design on hydrogel is a promising therapy for SCI regeneration with the potential for clinical translation.

Surgical technique: repair of forefoot skin and soft tissue defects using a lateral tarsal flap with a reverse dorsalis pedis artery pedicle: a retrospective study of 11 patients.

BACKGROUND: Various authors have proposed flaps to reconstruct traumatic forefoot skin and soft tissue defects, especially with exposure of tendon and/or bone although which is best for particular circumstances is unclear. DESCRIPTION OF TECHNIQUE: The indications for the technique were a forefoot defect area of no more than 8-cm × 8-cm and a well-preserved lateral tarsal (LT) donor site. The injured tendons were repaired using tendon grafts. The free dorsalis pedis flap was outlined by centering it on the cutaneous branch of the LT artery and tailoring it to the size of the wound, allowing 0.5-cm margins in length and width. The flap was rotated around the plantar perforating branch of the dorsalis pedis artery (DPA) to cover the forefoot defect. The lateral dorsalis pedis cutaneous nerve was anastomosed with the recipient plantar nerve stump. The donor site was covered with an inguinal, full-thickness skin graft. PATIENTS AND METHODS: Traumatic forefoot skin and soft tissue defects with exposure of the tendon and/or bone involving 11 feet in 11 patients (mean age, 32 years) were covered using a LT flap with a reversed DPA pedicle. Three patients with forefoot defects underwent emergency repair within 8 hours of injury, whereas eight patients required delayed repair. All patients were followed up for at least 6 months (mean, 13 months; range, 6-24 months). RESULTS: All flaps survived uneventfully, except for two that had superficial marginal necrosis or severe venous insufficiency. All skin grafts covering the donor sites survived and all wounds healed. None of the patients had restricted standing or walking at followups. The two-point discrimination was 4 mm to 10 mm at 6 months postoperative. The mean hallux-metatarsophalangeal-interphalangeal scale score was 93 points (range, 87-98 points). CONCLUSIONS: Our observations suggest the LT flap with a reversed DPA pedicle is a reasonable option for repair of traumatic forefoot skin and soft tissue defects with exposure of tendon and/or bone but a well-preserved LT donor site and is associated with minimal morbidity.

Enoxaparin sodium bone cement displays local anti-inflammatory effects by regulating the expression of IL-6 and TNF-α.

Objective: To explore the roles of Enoxaparin Sodium-Polymethyl methacrylate bone cement on inflammatory factors Interleukin-6 and Tumour Necrosis Factor-α in a rabbit knee replacement model. As well as the mechanisms underlying its potential effects on lipopolysaccharide-induced endothelial cell injury. Methods: A knee replacement model was established using New Zealand rabbits. Forty rabbits were randomly divided into four groups: PMMA, ES-PMMA, sham-operated, and blank control groups (n = 10 in each group). Local tissues around the incision were taken at the 30th, 60th, and 90th minute after the surgical implantation of the corresponding bone cement. Immunohistochemistry in the surgical field was used to measure the expression of local inflammatory factors IL-6 and TNF-α. In the in vitro experiments, 1 cm3 of bone cement was immersed in 3 mL of the medium for 24 h. The bone cement was discarded and diluted to 25% with normal medium. Pre-experiments were screened for the best LPS-inducing concentration of 100 mg/mL, and the most compatible LPS concentration was used for subsequent experiments simulating the primary cultures of rats' Inferior Vena Cava Endothelial Cells. The experiments were divided into four groups: blank control group, LPS induction group, PMMA + LPS group, and ES-PMMA + LPS group. The apoptosis rate was detected by flow cytometry, and the expression levels of TNF-α and IL-6 in the cells and supernatant were measured by ELISA, western blotting, and immunofluorescence. Results: According to immunohistochemical results, IL-6-positive cells were concentrated in the tissue interstitial space. In the PMMA and sham-operated groups, the number of IL-6-positive cells gradually increased over time. At all time points, IL-6 expression in the ES-PMMA group was much lower than in the PMMA and sham-operated groups. At 30 min, TNF-α positive cells in the ES-PMMA group expressed less than those in the PMMA and sham-operated groups, with no discernible difference between the PMMA and ES-PMMA groups at 60 or 90 min. Using ELISA and flow cytometry, the expression levels of IL-6 and TNF-α were improved and the apoptosis rate was magnified in the LPS-induced group (***P < 0.001) in contrast with the blank control group. Additionally, the expression levels of IL-6 and TNF-α were reduced in the ES-PMMA + LPS group compared with the LPS-induced group (*P < 0.05) and the apoptosis rate was reduced (***P < 0.001), with statistically significant variations. Western blotting and immunofluorescence analysis confirmed that IL-6 and TNF-α protein expression in cells was upregulated in the LPS-induced group compared to the blank control group (***P < 0.001), and the mean fluorescence intensity was enlarged (***P < 0.001). Meanwhile, IL-6 and TNF-α expression in the ES-PMMA + LPS group were down-regulated (**P < 0.01 or *P < 0.05) compared with the LPS-induced group and PMMA + LPS crew protein expression, and the average fluorescence intensity of IL-6 and TNF-α was lowered in the ES-PMMA + LPS group compared to the LPS-induced group (***P < 0.001). Conclusions: ES-PMMA bone cement reduced the expression levels of local inflammatory factors IL-6 and TNF-α in a rabbit knee model. ES-PMMA bone cement reduced the rate of LPS-induced endothelial cell apoptosis and diminished local inflammatory damage by regulating the secretion of inflammatory factors TNF-α and IL-6.

ATF2-driven osteogenic activity of enoxaparin sodium-loaded polymethylmethacrylate bone cement in femoral defect regeneration.

BACKGROUND: Polymethylmethacrylate (PMMA) bone cement loaded with enoxaparin sodium (PMMA@ES) has been increasingly highlighted to affect the bone repair of bone defects, but the molecular mechanisms remain unclear. We addressed this issue by identifying possible molecular mechanisms of PMMA@ES involved in femoral defect regeneration based on bioinformatics analysis and network pharmacology analysis. METHODS: The upregulated genes affecting the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) were selected through bioinformatics analysis, followed by intersection with the genes of ES-induced differentiation of BMSCs identified by network pharmacology analysis. PMMA@ES was constructed. Rat primary BMSCs were isolated and cultured in vitro in the proliferation medium (PM) and osteogenic medium (OM) to measure alkaline phosphatase (ALP) activity, mineralization of the extracellular matrix, and the expression of RUNX2 and OCN using gain- or loss-of-function experiments. A rat femoral bone defect model was constructed to detect the new bone formation in rats. RESULTS: ATF2 may be a key gene in differentiating BMSCs into osteoblasts. In vitro cell assays showed that PMMA@ES promoted the osteogenic differentiation of BMSCs by increasing ALP activity, extracellular matrix mineralization, and RUNX2 and OCN expression in PM and OM. In addition, ATF2 activated the transcription of miR-335-5p to target ERK1/2 and downregulate the expression of ERK1/2. PMMA@ES induced femoral defect regeneration and the repair of femoral defects in rats by regulating the ATF2/miR-335-5p/ERK1/2 axis. CONCLUSION: The evidence provided by our study highlighted the ATF2-mediated mechanism of PMMA@ES in the facilitation of the osteogenic differentiation of BMSCs and femoral defect regeneration.

Enoxaparin sodium bone cement plays an anti-inflammatory immunomodulatory role by inducing the polarization of M2 macrophages.

OBJECTIVE: The implantation of PMMA bone cement results in an immune response and the release of PMMA bone cement particles causes an inflammatory cascade. Our study discovered that ES-PMMA bone cement can induce M2 polarization of macrophages, which has an anti-inflammatory immunomodulatory effect. We also delved into the molecular mechanisms that underlie this process. METHODS: In this study, we designed and prepared samples of bone cement. These included PMMA bone cement samples and ES-PMMA bone cement samples, which were implanted into the back muscles of rats. At 3, 7, and 14 days after the operation, we removed the bone cement and a small amount of surrounding tissue. We then performed immunohistochemistry and immunofluorescence to observe the polarization of macrophages and the expression of related inflammatory factors in the surrounding tissues. The RAW264.7 cells were exposed to lipopolysaccharide (LPS) for 24 h to establish the macrophage inflammation model. Then, each group was treated with enoxaparin sodium medium, PMMA bone cement extract medium, and ES-PMMA bone cement extract medium, respectively, and cultured for another 24 h. We collected cells from each group and used flow cytometry to detect the expressions of CD86 and CD206 in macrophages. Additionally, we performed RT-qPCR to determine the mRNA levels of three markers of M1 macrophages (TNF-α, IL-6, iNOS) and two M2 macrophage markers (Arg-1, IL-10). Furthermore, we analyzed the expression of TLR4, p-NF-κB p65, and NF-κB p65 through Western blotting. RESULTS: The immunofluorescence results indicate that the ES-PMMA group exhibited an upregulation of CD206, an M2 marker, and a downregulation of CD86, an M1 marker, in comparison to the PMMA group. Additionally, the immunohistochemistry results revealed that the levels of IL-6 and TNF-α expression were lower in the ES-PMMA group than in the PMMA group, while the expression level of IL-10 was higher in the ES-PMMA group. Flow cytometry and RT-qPCR analyses revealed that the expression of M1-type macrophage marker CD86 was significantly elevated in the LPS group compared to the NC group. Additionally, M1-type macrophage-related cytokines TNF-α, IL-6, and iNOS were also found to be increased. However, in the LPS + ES group, the expression levels of CD86, TNF-α, IL-6, and iNOS were decreased, while the expression of M2-type macrophage markers CD206 and M2-type macrophage-related cytokines (IL-10, Arg-1) were increased compared to the LPS group. In comparison to the LPS + PMMA group, the LPS + ES-PMMA group demonstrated a down-regulation of CD86, TNF-α, IL-6, and iNOS expression levels, while increasing the expression levels of CD206, IL-10, and Arg-1. Western blotting results revealed a significant decrease in TLR4/GAPDH and p-NF-κB p65/NF-κB p65 in the LPS + ES group when compared to the LPS group. Additionally, the LPS + ES-PMMA group exhibited a decrease in TLR4/GAPDH and p-NF-κB p65/NF-κB p65 levels when compared to the LPS + PMMA group. CONCLUSION: ES-PMMA bone cement is more effective than PMMA bone cement in down-regulating the expression of the TLR4/NF-κB signaling pathway. Additionally, it induces macrophages to polarize towards the M2 phenotype, making it a crucial player in anti-inflammatory immune regulation.