SCG10 is required for peripheral axon maintenance and regeneration in mice.

Proper microtubule dynamics are critical for neuronal morphogenesis and functions, and their dysregulation results in neurological disorders and regeneration failure. Superior cervical ganglion-10 (SCG10, also known as stathmin-2 or STMN2) is a well-known regulator of microtubule dynamics in neurons, but its functions in the peripheral nervous system remain largely unknown. Here, we show that Scg10 knockout mice exhibit severely progressive motor and sensory dysfunctions with significant sciatic nerve myelination deficits and neuromuscular degeneration. Additionally, increased microtubule stability, shown by a significant increase in tubulin acetylation and decrease in tubulin tyrosination, and decreased axonal transport were observed in Scg10 knockout dorsal root ganglion (DRG) neurons. Furthermore, SCG10 depletion impaired axon regeneration in both injured mouse sciatic nerve and cultured DRG neurons following replating, and the impaired axon regeneration was found to be induced by a lack of SCG10-mediated microtubule dynamics in the neurons. Thus, our results highlight the importance of SCG10 in peripheral axon maintenance and regeneration.

Advances in Polysaccharides for Cartilage Tissue Engineering Repair: A Review.

Cartilage repair has been a significant challenge in orthopedics that has not yet been fully resolved. Due to the absence of blood vessels and the almost cell-free nature of mature cartilage tissue, the limited ability to repair cartilage has resulted in significant socioeconomic pressures. Polysaccharide materials have recently been widely used for cartilage tissue repair due to their excellent cell loading, biocompatibility, and chemical modifiability. They also provide a suitable microenvironment for cartilage repair and regeneration. In this Review, we summarize the techniques used clinically for cartilage repair, focusing on polysaccharides, polysaccharides for cartilage repair, and the differences between these and other materials. In addition, we summarize the techniques of tissue engineering strategies for cartilage repair and provide an outlook on developing next-generation cartilage repair and regeneration materials from polysaccharides. This Review will provide theoretical guidance for developing polysaccharide-based cartilage repair and regeneration materials with clinical applications for cartilage tissue repair and regeneration.

Prospects of Using Chitosan-Based Biopolymers in the Treatment of Peripheral Nerve Injuries.

Peripheral nerve injuries are common neurological disorders, and the available treatment options, such as conservative management and surgical repair, often yield limited results. However, there is growing interest in the potential of using chitosan-based biopolymers as a novel therapeutic approach to treating these injuries. Chitosan-based biopolymers possess unique characteristics, including biocompatibility, biodegradability, and the ability to stimulate cell proliferation, making them highly suitable for repairing nerve defects and promoting nerve regeneration and functional recovery. Furthermore, these biopolymers can be utilized in drug delivery systems to control the release of therapeutic agents and facilitate the growth of nerve cells. This comprehensive review focuses on the latest advancements in utilizing chitosan-based biopolymers for peripheral nerve regeneration. By harnessing the potential of chitosan-based biopolymers, we can pave the way for innovative treatment strategies that significantly improve the outcomes of peripheral nerve injury repair, offering renewed hope and better prospects for patients in need.

The Porous Structure of Peripheral Nerve Guidance Conduits: Features, Fabrication, and Implications for Peripheral Nerve Regeneration.

Porous structure is an important three-dimensional morphological feature of the peripheral nerve guidance conduit (NGC), which permits the infiltration of cells, nutrients, and molecular signals and the discharge of metabolic waste. Porous structures with precisely customized pore sizes, porosities, and connectivities are being used to construct fully permeable, semi-permeable, and asymmetric peripheral NGCs for the replacement of traditional nerve autografts in the treatment of long-segment peripheral nerve injury. In this review, the features of porous structures and the classification of NGCs based on these characteristics are discussed. Common methods for constructing 3D porous NGCs in current research are described, as well as the pore characteristics and the parameters used to tune the pores. The effects of the porous structure on the physical properties of NGCs, including biodegradation, mechanical performance, and permeability, were analyzed. Pore structure affects the biological behavior of Schwann cells, macrophages, fibroblasts, and vascular endothelial cells during peripheral nerve regeneration. The construction of ideal porous structures is a significant advancement in the regeneration of peripheral nerve tissue engineering materials. The purpose of this review is to generalize, summarize, and analyze methods for the preparation of porous NGCs and their biological functions in promoting peripheral nerve regeneration to guide the development of medical nerve repair materials.

Does segmental artery occlusion cause intravertebral cleft following osteoporotic vertebral fracture: a prospective magnetic resonance angiography study.

BACKGROUND: The avascular necrosis (AVN) hypothesis of intravertebral cleft (IVC) formation in osteoporotic vertebral fracture (OVCF) has received increasing attention. The aim of this article is to detect whether the segmental artery occlusion causes the IVC following OVCF. METHODS: Between December 2019 and April 2020, 44 OVCF patients with 46 fracture levels were prospectively enrolled and the vertebral segmental arteries were evaluated by magnetic resonance angiography (MRA). The artery conditions were divided into patent, narrow and occluded. The lesion segmental occlusion rate (LSOR) and the total occlusion rate (TOR) were calculated. The association of segmental artery occlusion and IVC formation was assessed. RESULTS: LOSR was 15.34% and TOR was 15.12%. The segmental arteries of the unfractured vertebrae had a higher occlusion rate at thoracolumbar levels than at non-thoracolumbar levels. There was no significant difference between the IVC group and the non-IVC group in the fractured levels artery occlusion rate (20.24 ± 28.08 vs 9.78 ± 19.56, P = 0.156) or the total segmental arteries occlusion rate (13.83 ± 12.04 vs 11.57 ± 9.25, P = 0.476). CONCLUSIONS: In patients with vertebral osteoporotic fracture, segmental artery occlusion is not associated with the development of intravertebral cleft.

Polymer Scaffolds for Biomedical Applications in Peripheral Nerve Reconstruction.

The nervous system is a significant part of the human body, and peripheral nerve injury caused by trauma can cause various functional disorders. When the broken end defect is large and cannot be repaired by direct suture, small gap sutures of nerve conduits can effectively replace nerve transplantation and avoid the side effect of donor area disorders. There are many choices for nerve conduits, and natural materials and synthetic polymers have their advantages. Among them, the nerve scaffold should meet the requirements of good degradability, biocompatibility, promoting axon growth, supporting axon expansion and regeneration, and higher cell adhesion. Polymer biological scaffolds can change some shortcomings of raw materials by using electrospinning filling technology and surface modification technology to make them more suitable for nerve regeneration. Therefore, polymer scaffolds have a substantial prospect in the field of biomedicine in future. This paper reviews the application of nerve conduits in the field of repairing peripheral nerve injury, and we discuss the latest progress of materials and fabrication techniques of these polymer scaffolds.

Risk factors for cement leakage and nomogram for predicting the intradiscal cement leakage after the vertebra augmented surgery.

BACKGROUND: Vertebral augmentation is the first-line treatment for the osteoporosis vertebral compression fractures. Bone cement leakage is the most common complication of this surgery. This study aims to assess the risk factors for different types of cement leakage and provides a nomogram for predicting the cement intradiscal leakage. METHODS: We retrospectively reviewed 268 patients who underwent vertebral augmentation procedure between January 2015 and March 2019. The cement leakage risk factors were evaluated by univariate analysis. Different types of cement leakage risk factors were identified by the stepwise logistic analysis. We provided a nomogram for predicting the cement intradiscal leakage and used the concordance index to assess the prediction ability. RESULTS: A total of 295 levels of vertebrae were included, with a leakage rate of 32.5%. Univariate analysis showed delayed surgery and lower vertebral compression ratio were the independent risk factors of cement leakage. The stepwise logistic analysis revealed percutaneous vertebroplasty was a risk factor in vein cement leakage; delayed surgery, preoperative compression ratio, and upper endplate disruption were in intradiscal cement leakage; age, preoperative fracture severity, and intravertebral vacuum cleft were in perivertebral soft tissue cement leakage; no factor was in spinal canal cement leakage. The nomogram for intradiscal cement leakage had a precise prediction ability with an original concordance index of 0.75. CONCLUSIONS: Delayed surgery and more vertebral compression increase the risk of cement leakage. Different types of cement leakage have different risk factors. We provided a nomogram for precise predicting the intradiscal cement leakage.

[Multi-center retrospective analysis of clinical and related sociologic characteristics of postoperative distal radius fracture patients].

OBJECTIVE: To study clinical-related characteristics of sociology of postoperative distal radius fracture patients. METHODS: A multi-center retrospective research was conducted on the information of the case evaluation and follow-up, including the patients' gender, age, habits, history of chronic diseases, conditions of fracture, length of hospital stay and treatments. The epidemiology data were analyzed with SPSS15.0. RESULTS: Of the entire 143 patients, 52 were male (average age: 41), and 91 were female (average age: 61). The different gender and age groups had significant distinction in the characteristics of injury. The length of hospital stay was influenced by the energy of injury. CONCLUSION: To reduce the damage or incidence of distal radius fracture, we should avoid falling, strengthen protection awareness, treat internal medicine diseases or osteoporosis and so on. The knowledge of characteristics of sociology and injury of distal radius fracture is beneficial to the prevention and treatment.

[Surgical treatment of internal fixation failure after clavicular fracture operation].

OBJECTIVE: To investigate the surgical treatment results of implant failure after clavicular fracture open reduction and internal fixation (ORIF). METHODS: Fifteen cases from Jan. 2005 to Jan. 2013 were treated surgically according to fracture classification, time of implant failure and implant type. The fracture union, shoulder function and pain were evaluated postoperatively. RESULTS: All the patients had full follow-up for 5 to 101 months (mean: 43.8 months). All the fractures were united well. The constant scores to assess the shoulder function were 82 to 100 (mean: 93.3 in the fracture side) and were 85 to 100 (mean: 96.7 in the uninjured side); statistically significant difference of the constant scores between the two sides was found (P=0.02). Eight cases did not have shoulder pain in the fracture side, while the other 7 cases had mild pain, The visual analogue scale (VAS) scores to evaluate shoulder pain were 1 to 3 in the fracture side, which were statistically different from those in the uninjured side (P=0.03). CONCLUSION: Implant instability causes early implant failure after clavicular fracture ORIF and re-fixation with stable implant is effective. Fracture nonunion leads to late implant failure, and bridging fixation using locking plate associated with bony autograft with iliac crest is a successful method to treat atrophy clavicular nonunion. Surgical treatment can bring good results.

[Traffic injuries of pre-hospital treatment in the urban area of Beijing].

OBJECTIVE: To evaluate the current condition of urban road traffic injuries (RTIs) according to Beijing Emergency Medical Center (BEMC) from Jan. 1, 2004 to Dec. 31, 2010, analyze the social characteristics and explore the possible methods for prevention and improvement. METHODS: Using data from the Beijing Emergency Medical Center, we collected 19 550 victims who were involved in RTIs in Beijing from Jan. 1, 2004 to Dec. 31, 2010. The personal information, time of the injury event, road user type and striking vehicle type, as well as the site and severity of injury, were analyzed using Excel 2007 and SPSS 17.0 software with ANOVA of variance and Chi-squared tests. RESULTS: The annual rate of RTIs was 120.0 per 100 000 people in Beijing, and the mortality rate was about 4.97 per 100 000 people. Male victims were more than female victims (11 737 persons vs. 7 618 persons).The mean age was (72.92 ± 5.67) years. Overall, RTIs in all the age groups happened in October commonly, and were inclined to daytime, especially at noon. But different age groups had their special hour distribution features of RTIs. Traffic collisions occurred most frequently in pedestrians and cyclists (7 588,38.81%;3 790,19.39%). Majorities of victims presented with head injuries and lower-limb injuries(8 343,42.68%; 6 828,34.93%). These collisions included car striking accidents (11 490, 58.77%). And most of the older adults were classified as medium in severity (11 718, 59.94%). CONCLUSION: The prevention and treatment of RTIs, should focus on targeted prevention solutions and standardized pre-hospital rescue, according to specific population, time interval and vehicle usage.

Hydrophobic Cross-Linked Chains Regulate High Wet Tissue Adhesion Hydrogel with Toughness, Anti-hydration for Dynamic Tissue Repair.

Hydrogel adhesion materials are widely reported for tissue engineering repair applications, however, wet tissue surface moisture can reduce the wet-adhesion properties and mechanical strength of hydrogels limiting their application. Here, anti-hydration gelatin-acrylic acid-ethylene dimethacrylate (GAE) hydrogels with hydrophobic cross-linked chains are constructed. The prepared GAE hydrogel is soaked in PBS (3 days) with a volume change of 0.6 times of the original and the adhesive strength, Young's modulus, toughness, and burst pressure are maintained by ≈70% of the original. A simple and universal method is used to introduce hydrophobic chains as cross-linking points to prepare hydrogels with anti-hydration, toughness, and high wet state adhesion. The hydrophobic cross-linked chains not only restrict the movement of molecular chains but also hinder the intrusion of water molecules. Antihydration GAE hydrogels exhibit good biocompatibility, slow drug release, and dynamic oral wet-state tissue repair properties. Therefore, the anti-hydration hydrogel has excellent toughness, wet tissue adhesion properties, and good prospects for biological applications.

Traditional Chinese medicine residue enzymatic hydrolysates for production of polyhydroxyalkanoate by newly isolated Bacillus altitudinis.

Traditional Chinese medicine residue (TCMR) was utilized as an inexpensive carbon source for the production of poly(3-hydroxybutyrate) (PHB) using the newly isolated Bacillus altitudinis HBU-SI7. The results showed that Yu Ping Feng TCMR could be directly hydrolysed by cellulase to obtain a high proportion of glucose (99 % of total sugar) without pretreatment, achieving an enzymatic hydrolysis rate of up to 89.2 %. B. altitudinis could grow and produce PHB when using enzymatically hydrolysed TCMR in a 5-L fermenter. After 20 h of fermentation, the maximum concentration of PHB was 11.2 g/L, and the highest cell dry weight (CDW) was 15.4 g/L, with 72.7 % of the PHB fraction in CDW. Moreover, this strain could utilize enzymatic hydrolysates from various herbal formulas to produce high levels of PHB. This novel approach aims to accumulate PHB from TCMR hydrolysates, offering an effective and environmentally friendly method to reduce production costs and achieve mass production.

Growth factors: Bioactive macromolecular drugs for peripheral nerve injury treatment - Molecular mechanisms and delivery platforms.

Bioactive macromolecular drugs known as Growth Factors (GFs), approved by the Food and Drug Administration (FDA), have found successful application in clinical practice. They hold significant promise for addressing peripheral nerve injuries (PNIs). Peripheral nerve guidance conduits (NGCs) loaded with GFs, in the context of tissue engineering, can ensure sustained and efficient release of these bioactive compounds. This, in turn, maintains a stable, long-term, and effective GF concentration essential for treating damaged peripheral nerves. Peripheral nerve regeneration is a complex process that entails the secretion of various GFs. Following PNI, GFs play a pivotal role in promoting nerve cell growth and survival, axon and myelin sheath regeneration, cell differentiation, and angiogenesis. They also regulate the regenerative microenvironment, stimulate plasticity changes post-nerve injury, and, consequently, expedite nerve structure and function repair. Both exogenous and endogenous GFs, including NGF, BDNF, NT-3, GDNF, IGF-1, bFGF, and VEGF, have been successfully loaded onto NGCs using techniques like physical adsorption, blend doping, chemical covalent binding, and engineered transfection. These approaches have effectively promoted the repair of peripheral nerves. Numerous studies have demonstrated similar tissue functional therapeutic outcomes compared to autologous nerve transplantation. This evidence underscores the substantial clinical application potential of GFs in the domain of peripheral nerve repair. In this article, we provide an overview of GFs in the context of peripheral nerve regeneration and drug delivery systems utilizing NGCs. Looking ahead, commercial materials for peripheral nerve repair hold the potential to facilitate the effective regeneration of damaged peripheral nerves and maintain the functionality of distant target organs through the sustained release of GFs.

Strategies for Treating Traumatic Neuromas with Tissue-Engineered Materials.

Neuroma, a pathological response to peripheral nerve injury, refers to the abnormal growth of nerve tissue characterized by disorganized axonal proliferation. Commonly occurring after nerve injuries, surgeries, or amputations, this condition leads to the formation of painful nodular structures. Traditional treatment options include surgical excision and pharmacological management, aiming to alleviate symptoms. However, these approaches often offer temporary relief without addressing the underlying regenerative challenges, necessitating the exploration of advanced strategies such as tissue-engineered materials for more comprehensive and effective solutions. In this study, we discussed the etiology, molecular mechanisms, and histological morphology of traumatic neuromas after peripheral nerve injury. Subsequently, we summarized and analyzed current nonsurgical and surgical treatment options, along with their advantages and disadvantages. Additionally, we emphasized recent advancements in treating traumatic neuromas with tissue-engineered material strategies. By integrating biomaterials, growth factors, cell-based approaches, and electrical stimulation, tissue engineering offers a comprehensive solution surpassing mere symptomatic relief, striving for the structural and functional restoration of damaged nerves. In conclusion, the utilization of tissue-engineered materials has the potential to significantly reduce the risk of neuroma recurrence after surgical treatment.

Biodegradable conduit small gap tubulization for peripheral nerve mutilation: a substitute for traditional epineurial neurorrhaphy.

Nerve regeneration and re-innervation are usually difficult after peripheral nerve injury. Epineurium neurorrhaphy to recover the nerve continuity is the traditional choice of peripheral nerve mutilation without nerve defects, whereas the functional recovery remains quite unsatisfactory. Based on previous research in SD rats and Rhesus Monkeys, a multiple centers clinical trial about biodegradable conduit small gap tubulization for peripheral nerve mutilation to substitute traditional epineurial neurorrhaphy was carried out. Herein, the authors reviewed the literature that focused on peripheral nerve injury and possible clinical application, and confirmed the clinical possibilities of biodegradable conduit small gap tubulization to substitute traditional epineurial neurorrhaphy for peripheral nerve mutilation. The biodegradable conduit small gap tubulization to substitute traditional epineurial neurorrhaphy for peripheral nerve mutilation may be a revolutionary innovation in peripheral nerve injury and repair field.

[Minimal invasive internal fixation with U-shaped break-off pedicle screws for treatent of thoracolumbar fractures].

OBJECTIVE: To investigate the clinical outcome of minimal invasive internal fixation with U-shaped break-off pedicle screws through paraspinal muscle sparing approach to treat thoracolumbar fractures, and to discuss its advantages. METHODS: From August 2010 to June 2012, we had 40 thoracolumber fractures patients (27 males and 13 females). Their ages ranged from 22 to 60 years. Of the 40 cases, 4 were T11 fractures, 13 T12 fractures ,17 L1 fractures,6 L2 fractures. According to Denis classification,all of them were burst fractures, with vertebral canal compromise less than 1/3. According to AO classification they were type A or type B1 injuries. All the cases had no nerve injury. The patients were randomly divided into two groups. With Group A (20 cases) we took the method of minimal invasive internal fixation with U-shaped break-off pedicle screws to fix one level above and below the injured vertebra through the parespinal muscle sparing approach. With Group B (20 cases), we took the traditional posterior midline approach and open procedure. Then we compared the two groups by operation time, blood loss, drainage, Visual Analogue Scales and X-ray exposure. RESULTS: Minimal invasive group had obvious advatages in operation time, bleeding control and early pain relief of post-operation. The X-ray exposure and long-term follow-up outcome were almost the same. CONCLUSION: Through paraspinal muscle sparing approach minimal invasive internal fixtation with U-shaped break-off pedicle screws to treat thoracolumber has more advantages than traditional procedure in blood control and quick recovery. The method needs no special instruments and don't increase X-ray exposure.

[Surgical treatment of deltoid ligament injury associated with ankle fractures].

OBJECTIVE: To observe the clinical outcome after the surgical treatment of the deltoid ligament injury associated with ankle fractures. METHODS: From January 2005 to December 2009, 16 deltoid ligament ruptures associated with ankle fractures were repaired. According to the AO/OTA system, 2 cases belonged to fracture A, 8 to B, and 6 to C. Radiographs, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scores and visual analogue scale (VAS) were used for the outcome measurements. RESULTS: The 16 patients were followed up for 30 to 84 months,with the mean follow-up of 47 months. All wounds healed at the first stage. The mean time of bone union was 12.8 weeks (range: 10-14 weeks). The mean AOFAS ankle-hindfoot score in the last follow-up was 93 points (range: 85-100 points). The mean score of VAS was 0.94 points (range: 0-2 points). CONCLUSION: Surgical treatment of ankle fractures associated with deltoid ligament rupture can achieve satisfactory outcomes, but it is important to decide the operation indication.

[Generation and characterization of peripheral nerve animal model of pure motor/sensory nerve fibers].

OBJECTIVE: To generate peripheral nerve animal model of pure motor nerve fibers/pure sensory nerve fibers, and identify them. METHODS: The SPF SD rats were adopted in this study, and divided into 3 groups. In group A, we ablated L2-L4 ventral roots (VRs) to generate peripheral nerve animal model of pure sensory fibers. In group B, we ablated L2-L4 dorsal root ganglions (DRGs) to generate peripheral nerve animal model of pure motor fibers. Two time end-points were set as 2 weeks and 4 weeks. Neuron cells in lumbar spinal cords were detected by immunohistochemical staining with antibody of neuronal nuclei (NeuN). Motor neuron cells in lumbar spinal cords of pure motor fiber animal models and sensory neuron cells in lumbar spinal cords of pure sensory fiber animal models were counted respectively, and then compared to that of normal animals. Femoral nerves distal to the furcation were stained in osmium tetroxide, and then myelinated nerve fibers in the muscle branch and cutaneous branch of femoral nerve were counted respectively. RESULTS: The mean numbers of sensory neuron cells and motor neuron cells in normal lumbar spinal cords were 62.57 ± 1.02 and 29.73 ± 3.03 per 10 × 20 visual field respectively. For different end-points, the mean numbers of sensory neuron cells after ablating vental foots were 62.12 ± 1.77 (2 weeks), 62.15 ± 1.32 (4 weeks) per 10 × 20 visual field respectively; the mean numbers of motor neuron cells after ablating DRGs were 30.12 ± 0.44 (2 weeks), 30.00 ± 1.87 (4 weeks) per 10 × 20 visual field respectively. In group A, motor axons in muscle branch were degenerated as the sensory axons in muscle branch and cutaneous branch were not changed. The senory axons in femoral nerve for the two end-points were 1 558.17 ± 50.14 (2 weeks) and 1 544.00 ± 47.42 (4 weeks). In group B, sensory axons in muscle branch were degenerated as the motor axons were reserved. The motor axons in muscle branch for the two end-points were 387.67 ± 48.50 (2 weeks) and 393.50 ± 27.86 (4 weeks). There was no statistically significant difference in these mean numbers for the two end-points. The degenerating axons and myelin sheath had not been totally eliminated by the endpoint of 2 weeks. CONCLUSION: Peripheral nerve animal model of pure motor fibers can be generated by ablating L2-L4 DRGs; peripheral nerve animal model of pure sensory fibers can be generated by ablating L2-L4 ventral roots. The degenerating axons and myelin sheath have been totally eliminated by the end-point of 4 weeks. Ablating the ventral roots does not influence the survival of sensory neuron cells; and ablating the DRGs does not influence the survival of motor neuron cells.

[Treatment of comminuted clavicle shaft fractures with provisional intra-medullary K-wire fixation and bridging plate internal fixation].

OBJECTIVE: To discuss the operation effect of comminuted clavicle shaft fractures with provisional intramedullary K-wire fixation and bridging plate internal fixation. METHODS: From Mar. 2008 to Jul. 2012, 22 cases of comminuted clavicle shaft fractures was treated with open reduction, and provisional intramedullary K-wire fixation and bridging plate internal fixation. The fracture healing was investigated through X-rays. The 22 cases were followed up to evaluate the function of the affected shoulder with Constant score. RESULTS: Through the follow-up for average 15 months, all the fractures healed and the average healed time was 14.6 weeks. The average Constant score of the affected shoulder was 95.3. There were 13 excellent cases, 7 good cases, and 2 fair cases. The fineness rate was 90.9% (20/22). Soft tissue problem resulting from plate tilting occurred in 2 cases. At last, they accepted second operation to remove the implant. CONCLUSION: Applying provisional intramedullary K-wire fixation and bridging plate internal fixation in comminuted clavicle shaft fractures, makes procedure simple, improves healing rate and decreases the complications.