Biodegradable quaternized silk fibroin sponge with highly uniform pore structure for traumatic hemostasis and anti-infection.

Developing a biodegradable sponge with rapid shape recovery and potent antibacterial and coagulation properties for traumatic hemostasis and anti-infection remains challenging. Herein, we fabricated quaternized silk fibroin (SF) sponges by freeze-drying under a constant cooling rate and modification with quaternary ammonium groups. We found the constant cooling rate enabled the sponges with a highly uniform pore structure, which provided excellent self-elasticity and shape recovery. Decoration with quaternary ammonium groups enhanced blood cells adhesion, aggregation, and activation, as well as resistance to infections from Staphylococcus aureus and Escherichia coli. The SF sponge had superior hemostatic capacity to gauze and commercial gelatin sponge in different hemorrhage models. The SF sponge exhibited favorable biodegradability and biocompatibility. Moreover, The SF sponge also promoted host cell infiltration, capillary formation, and tissue ingrowth, suggesting its potential for guiding tissue regeneration. The developed SF sponge holds great application prospects for traumatic hemostasis, anti-infection, and guiding tissue regeneration.

A macroporous composite sponge with high water absorbency and active coagulation mechanism for traumatic hemostasis and anti-infection.

The development of a composite sponge with high water absorbency and active coagulation mechanism for traumatic hemostasis and anti-infection remains a challenge. Herein, we developed a composite sponge using gelation, swelling, and freeze-drying methods based on quaternized chitosan, succinimidyl-modified F127, and bioactive glass. The sponge exhibited macroporous structure, high porosity, and water absorbency. When exposed to blood, it strongly interacted with blood cells, promoting their adhesion, aggregation, and activation. Moreover, it activated the intrinsic coagulation pathway. The sponge/powder demonstrated superior hemostatic capacity to commercial gauze, gelatin sponge, Yunnan Baiyao, and chitosan hemostatic powder in rat tail amputation, liver superficial injury, liver resection, and liver semi-perforation wound models. The sponge also presented robust anti-infection activity against methicillin-resistantStaphylococcus aureusandEscherichia coli. Additionally, the sponge showed low cytotoxicity, hemolysis activity, inflammation response, and systemic toxicity, demonstrating its favorable biocompatibility.

A self-elastic chitosan sponge integrating active and passive hemostatic mechanisms for effectively managing uncontrolled coagulopathic hemorrhage.

Developing a self-elastic sponge integrating active and passive hemostatic mechanisms for the effective management of uncontrolled coagulopathic hemorrhage remains a challenge. We here developed a chitosan-based sponge by integrating freeze-drying, chemical decoration of alkyl chains and phosphate groups, and physical loading of thrombin. The sponge exhibited high mechanical strength, self-elasticity, and rapid shape recovery. The sponge facilitated blood cell adhesion, aggregation, and activation through hydrophobic and electrostatic interactions, as well as accelerated blood clotting. The sponge exhibited higher efficacy than commercial gauze and gelatin sponge in managing uncontrolled hemorrhage from heparinized rat tail amputation, liver superficial injury, and liver perforating wound models. In addition, the sponge exhibited favorable biodegradability and biocompatibility. These findings revealed that the developed sponge holds great potential as a novel hemostat for effectively managing uncontrolled coagulopathic hemorrhage from superficial and perforating wounds.

Efficacy of intradiscal injection of platelet-rich plasma in the treatment of discogenic low back pain: A single-arm meta-analysis.

BACKGROUND: Discogenic low back pain (DLBP) has been influencing people's quality of life. Research on platelet-rich plasma (PRP) for DLBP has increased in recent years, but systematic summaries are lacking. This study analyzes all published studies related to the use of intradiscal injection of PRP for the treatment of DLBP and summarizes evidence-based medicine for the efficacy of this biologic treatment for DLBP. METHODS: Articles published from the inception of the database to April 2022 were retrieved from PubMed, the Cochrane Library, Embase, ClinicalTrial, the Chinese National Knowledge Infrastructure, Wanfang, Chongqing VIP Chinese Scientific Journals, and the Chinese Biomedicine databases. After the rigorous screening of all studies on PRP for DLBP, a meta-analysis was performed. RESULTS: Six studies, including 3 randomized controlled trials and 3 prospective single-arm trials, were included. According to this meta-analysis, pain scores decreased by >30% and >50% from baseline, with incidence rates of 57.3%, 50.7%, and 65.6%, and 51.0%, 53.1%, and 51.9%, respectively, after 1, 2, and 6 months of treatment. The Oswestry Disability Index scores decreased by >30% with an incidence rate of 40.2% and by >50% with an incidence rate of 53.9% from baseline after 2 and 6 months, respectively. Pain scores decreased significantly after 1, 2, and 6 months of treatment (standardized mean difference: 1 month, -1.04, P = .02; 2 months, -1.33, P = .003; and 6 months, -1.42, P = .0008). There was no significant change (P > .05) in the pain scores and the incidence rate when pain scores decreased by >30% and >50% from baseline between 1 and 2 months, 1 and 6 months, and 2 and 6 months after treatment. No significant adverse reactions occurred in any of the 6 included studies. CONCLUSION: Intradiscal injection of PRP is effective and safe in the treatment of DLBP, and there was no significant change in the patient's pain 1, 2, and 6 months after PRP treatment. However, confirmation is required by additional high-quality studies due to the limitations of the quantity and quality of the included studies.

Research progress in decellularized extracellular matrix hydrogels for intervertebral disc degeneration.

As one of the most common clinical disorders, low back pain (LBP) influences patient quality of life and causes substantial social and economic burdens. Many factors can result in LBP, the most common of which is intervertebral disc degeneration (IDD). The progression of IDD cannot be alleviated by conservative or surgical treatments, and gene therapy, growth factor therapy, and cell therapy have their own limitations. Recently, research on the use of hydrogel biomaterials for the treatment of IDD has garnered great interest, and satisfactory treatment results have been achieved. This article describes the classification of hydrogels, the methods of decellularized extracellular matrix (dECM) production and the various types of gel formation. The current research on dECM hydrogels for the treatment of IDD is described in detail in this article. First, an overview of the material sources, decellularization methods, and gel formation methods is given. The focus is on research performed over the last three years, which mainly consists of bovine and porcine NP tissues, while for decellularization methods, combinations of several approaches are primarily used. dECM hydrogels have significantly improved mechanical properties after the polymers are cross-linked. The main effects of these gels include induction of stem cell differentiation to intervertebral disc (IVD) cells, good mechanical properties to restore IVD height after polymer cross-linking, and slow release of exosomes. Finally, the challenges and problems still faced by dECM hydrogels for the treatment of IDD are summarised, and potential solutions are proposed. This paper is the first to summarise the research on dECM hydrogels for the treatment of IDD and aims to provide a theoretical reference for subsequent studies.

Identification of compositional and structural changes in the nucleus pulposus of patients with cervical disc herniation by Raman spectroscopy.

Purpose: Cervical disc herniation (CDH) is one of the most common spinal diseases in modern society; intervertebral disc degeneration (IVDD) has long been considered as its primary cause. However, the mechanism of intervertebral disc degeneration is still unclear. The aim of the study is to examine the components and structures of proteoglycan and collagen in cervical disc herniated nucleus pulposus (NP) using a validated and convenient Raman spectra technique and histological methods to further elucidate the mechanism of IVDD at the microscopic level. Methods: Our study used a burgeoning technique of Raman spectroscopy combined with in vitro intervertebral disc NP to characterize the above mentioned research purposes. Firstly, we collected cervical disc NP samples and imaging data by certain inclusion and exclusion criteria. Then, we graded the NP of the responsible segment according to the patient's preoperative cervical magnetic resonance imaging (MRI) T2-weighted images by Pfirrmann grading criteria while measuring the T2 signal intensity value of NP. In addition, the structure of the NP samples was evaluated by histological staining (H&E staining and Safranin-O staining). Finally, the samples were scanned and analyzed by Raman spectroscopy. Results: A total of 28 NP tissues from 26 patients (two of these patients were cases that involved two segments) with CDH were included in this study. According to the Raman spectroscopy scan, the relative content of proteoglycans which is characterized by the ratio of the two peaks (I 1,064/ I 1,004) in the NP showed a significantly negative correlation with Pfirrmann grade (P < 0.001), while the collagen content and the NP intensity value showed a positive correlation (P < 0.001). For the microstructural characterization of collagen, we found that it may have an essential role in the degenerative process of the intervertebral disc. Moreover, histological staining (H&E staining and Safranin-O staining) showed the general structure of the NP and the distribution of macromolecules. Conclusion: The present study demonstrated the possibility of characterizing the macromolecular substances inside the cervical disc NP tissue by Raman spectroscopy. It also confirmed that macromolecular substances such as proteoglycans and collagen have some degree of alteration in content and structure during degeneration, which has a further positive significance for the elucidation of CDH's mechanism.

Constructing a Solar Evaporator with Salt-Collecting Paper by Stacking Hydrophilic Sponges for Freshwater Production and Salt Collection.

Solar water evaporation is universally considered as an effective method to alleviate the freshwater shortage worldwide. A series of three-dimensional, salt-resistant evaporators have been brought out to improve the evaporation performance. However, little attention was paid to the collection of salt from seawater and high salinity brine. In this work, a carbon black polyvinyl alcohol (PVA) sponge was prepared to harvest light using a physical adsorption method to load carbon black on the PVA sponge. The experimental results showed that optimal light absorption (97.8%) and evaporation rate (1.60 kg m-2 h-1) were achieved when the carbon black PVA sponge was produced at a carbon black concentration of 1 g L-1. Moreover, we stacked PVA sponges beneath the carbon black PVA sponge to construct a non-photothermal evaporation area. It was seen that the evaporator with an eight-layer PVA sponge had an excellent evaporation rate as high as 2.35 kg m-2 h-1. In addition, the salt-collecting paper, all-black printed by a laser printer, was inserted between the stacked PVA sponges for salt collection, and the eight-layer PVA sponge evaporator with the salt-collecting paper at the fourth floor was tested in a 2 h desalination experiment. The outcome indicated that a square meter of this evaporator can produce about 7.03 L of freshwater and 206 g of salt per day from 10 wt % NaCl solution. As a result, the solar evaporator developed in this work is capable of collecting salt and maintaining a high evaporation rate, which is of great competence in the fields of freshwater production and salt collection.

Construction of chitosan scaffolds with controllable microchannel for tissue engineering and regenerative medicine.

Microchannels are effective means of enabling the functional performance of tissue engineering scaffolds. Chitosan, a partial deacetylation derivative of chitin, exhibiting excellent biocompatibility, has been widely used in clinical practice. However, development of chitosan scaffolds with controllable microchannels architecture remains an engineering challenge. Here, we generated chitosan scaffolds with adjustable microchannel by combining a 3D printing microfiber templates-leaching method and a freeze-drying method. We can precisely control the arrangement, diameter and density of microchannel within chitosan scaffolds. Moreover, the integrated bilayer scaffolds with the desired structural parameters in each layer were fabricated and exhibited no delamination. The flow rate and volume of the simulated fluid can be modulated by diverse channels architecture. Additionally, the microchannel structure promoted cell survival, proliferation and distribution in vitro, and improved cell and tissue ingrowth and vascular formation in vivo. This study opens a new road for constructing chitosan scaffolds, and can further extend their application scope across tissue engineering and regenerative medicine.

Neuroprotective effect of neuregulin-1ß on spinal cord ischemia reperfusion injury.

Objective: This study was designed to see if neuregulin-1ß (NRG-1ß) plays a protective role in spinal cord ischemia and reperfusion injury (SCII).Design: Animal research.Setting: China.Participants: NA.Interventions: Forty-eight SD rats were randomly divided into control group (n = 16), SCII model group (n = 16) and NRG-1ß-treated group (n = 16). In control group, the abdominal aorta was isolated but not clipped. The rats in NRG-1ß-treated group were treated with 10µg/kg NRG-1ß during developing SCII model.Outcome Measures: Neurological scores were evaluated. At 3, 6, 12 and 24 h after the reperfusion, rats were killed. Pathological changes of spinal cord were assessed with HE staining, and immunohistochemical staining of matrix metalloproteinases-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1). MMP-9 and TIMP-1 mRNA levels were assessed using real-time PCR.Results: NRG-1ß reduced the damage of SCII in the rats. The expression of MMP-9 protein and mRNA in NRG-1ß treatment group was significantly lower than the model group (P < 0.05) at 6 h, 12 h and 24 h after the perfusion. The expression of TIMP-1 protein and mRNA in the treatment group was significantly higher than the model group at 12 h and 24 h after the perfusion.Conclusion: NRG-1ß reduced the reperfusion damage in rat model of SCII, in which process MMP-9 and TIMP-1 were probably involved.

Biomimetic angle-ply multi-lamellar scaffold for annulus fibrosus tissue engineering.

Constructing a biomimetic scaffold that replicates the complex architecture of intervertebral disc annulus fibrosus (AF) remains a major goal in AF tissue engineering. In this study, a biomimetic angle-ply multi-lamellar polycaprolactone/silk fibroin (PCL/SF) AF scaffold was fabricated. Wet-spinning was used to obtain aligned PCL/SF microfiber sheets, and these were excised into strips with microfibers aligned at +30° or -30° relative to the strip long axis. This was followed by stacking two strips with opposing fiber alignment and wrapping them concentrically around a mandrel. Our results demonstrated that the scaffold possessed spatial structure and mechanical properties comparable to natural AF. The scaffold supported rabbit AF cells adhesion, proliferation, infiltration and guided oriented growth and extracellular matrix deposition. In conclusion, our angle-ply multi-lamellar scaffold offers a potential solution for AF replacement therapy and warrants further attention in future investigations.

Identifying compositional and structural changes in the nucleus pulposus from patients with lumbar disc herniation using Raman spectroscopy.

Lower back pain (LBP) is one of the most common musculoskeletal complaints worldwide. Intervertebral disc degeneration (IDD) is considered to be a significant contributor to LBP; however, the mechanisms underlying IDD remain to be fully elucidated. One of the major features of IDD is the decreased content of type II collagen and proteoglycans in the nucleus pulposus (NP). The present study aimed to investigate the biochemical mechanisms of IDD at the microscopic level using Raman spectroscopy. Raman spectroscopy, based on inelastic scattering of light, is an emerging optical technique that may measure the chemical composition of complex biological samples, including biofluids, cells and tissues. In the present study, 30 NP tissue samples from 30 patients who were diagnosed with lumbar disc herniation and received spinal fusion surgery to relieve LBP were obtained and analyzed. Routine pre-operative 3.0T, T2-weighed MRI was used to classify the cases according to Pfirrmann grades and the T2 signal intensity value of the NP was measured. Subsequently, all NP samples were scanned and analyzed using a Laser MicroRaman Spectrometer at room temperature. The Raman spectral results demonstrated that the relative content of proteoglycans, expressed as the relative intensity ratio of two peaks (I1064/I1004), was significantly inversely correlated with the Pfirrmann grade (ρ=-0.6462; P<0.0001), whereas the content of collagen (amide I) was significantly positively correlated with the Pfirrmann grade (ρ=0.5141; P<0.01). In conclusion, the higher relative intensity of the ratio of two peaks (I1670/I1640; Amide I) represented a higher fractional content of disordered collagen, which suggested that the defective collagen structure may lead to NP abnormalities.

Correlation between C7 slope and cervical lordosis in patients after expansive open-door laminoplasty.

Purpose of the article: To investigate the correlation between C7 slope and cervical lordosis in patients after expansive open-door laminoplasty (EOLP).Material and methods: We retrospectively analyzed 57 patients who underwent EOLP between June 2013 and January 2017 in the Department of Spinal Surgery of our hospital. The operation time, intraoperative blood loss and follow-up time were recorded. The C7 slope, C2-7 sagittal vertical axis, and C2-7 Cobb angle were measured anteroposterior radiograph of the cervical spine preoperatively and postoperatively. All patients were divided into two groups according to the preoperative C7 slope (C7 slope ≤20° group and C7 slope >20° group).Results: The amount of intraoperative bleeding was 220.2 ± 180.9ml, and the operation time was 143.4 ± 51.2min. The average follow-up time was 24.9 ± 10.3months (range12-48 months). The C2-7 Cobb angle was 13.49 ± 10.46°at the final follow-up, which was significantly lower than that preoperatively (p = .026). But, The C7 slope and C2-7 sagittal vertical axis showed no significant difference between preoperatively and postoperatively. Preoperative and postoperative C7 slope and C2-7 Cobb angle were positively correlated to age and significant difference was observed. In the group of C7 slope >20°, significant difference was observed in term of the change of the C2-7 Cobb angle and C2-7SVA postoperatively (p = .009 and p= .020). However, there was no statistically significant difference detected in these two parameters in the group of C7 slope ≤20°.Conclusion: This study indicated that C7 slope could be used as an indicator of the change in the curvature of the cervical spine after EOLP. The loss of cervical curvature after surgery was prone to occur when C7 slope was greater than 20°, which should be noted in clinical practice.

Does Percutaneous Vertebroplasty or Balloon Kyphoplasty for Osteoporotic Vertebral Compression Fractures Increase the Incidence of New Vertebral Fractures? A Meta-Analysis.

BACKGROUND: Because of an aging population,osteoporotic vertebral fractures are becoming more frequent.Conservative therapy was considered the gold standard for treating osteoporotic vertebral compression fractures (OVCFs) in the past. Percutaneous vertebroplasty (PVP) or balloon kyphoplasty (BKP) as minimally invasive techniques are new treatments that are widely used for painful OVCFs. However, an increase in new vertebral compression fractures at non-treated levels following augmentation is of concern. There is no convincing evidence that new fractures are inevitable after augmentation compared to after conservative treatment, and it is still unclear whether further fractures are the consequence of augmentation or a result of the natural progression of osteoporosis. OBJECTIVE: The objective of this study was to evaluate the new-level fracture risk after PVP or BKP compared with conservative (non-operative) treatment and to determine the dominant risk factor associated with new OVCFs. STUDY DESIGN: A meta-analysis of comparative studies was performed to evaluate the incidence of new vertebral fractures between vertebral augmentation, such as vertebroplasty and kyphoplasty, and no operation. SETTING: The PubMed, ISI Web of Science, ELSEVIER ScienceDirect, and Cochrane Library databases and abstracts published in annual proceedings were systematically searched.In addition, we also retrieved data from references when titles met our inclusion criteria. METHODS: Detailed searches of a number of online databases comparing operative and non-operative groups were performed. We included randomized controlled trials,clinical controlled trials,and prospective clinical studies to provide available data. All studies were reviewed by two reviewers independently, and all the references that met our inclusion criteria were searched for additional trials, using the guidelines set by the QUOROM (Quality of Reporting of Meta-analysis) statement. RESULTS: We evaluated 12 studies encompassing 1,328 patients in total, including 768 who underwent operation with polymethylmethacrylateand 560 who received non-operative treatments. For new-level vertebral fractures, our meta-analysis found no significant difference between the 2 methods, including total new fractures (P = 0.55) and adjacent fractures (P = 0.5). For pre-existing vertebral fractures, there was no significant difference between the 2 groups (operative and non-operative groups) (P = 0.24). Additionally,there was no significant difference in bone mineral density, both in the lumbar (P = 0 .13) and femoral neck regions (P = 0.37), between the 2 interventions. LIMITATION: All studies we screened were published online except for unpublished articles. Moreover, only a few data sources could be extracted from the published studies.There were only 5 randomized clinical trials and 7 prospective studies that met our inclusion criteria. CONCLUSION: Vertebral augmentation techniques, such as vertebroplasty and kyphoplasty, have been widely used to treat osteoporotic vertebral fractures in order to alleviate back pain and correct the deformity, and it has been frequently reported that many new vertebral fractures occurred after this operation. Our analysis did not reveal evidence of an increased risk of fracture of vertebral bodies, especially those adjacent to the treated vertebrae, following augmentation with either method compared with conservative treatment.Key words: Vertebroplasty, kyphoplasty, new osteoporotic compression vertebral fracture, meta-analysis.

[Effect on elimination of pyrogen and effectual components of Panax notoginseng saponins by ultrafiltration membranes of different cut-off molecular weight and different materials].

OBJECTIVE: To study the elimination effect of bacterial endotoxins and the transmittance of Panax notoginseng saponins by ultrafiltration membranes of different cut-off molecular weight and different materials. METHODS: The kinetic-turbidimetric method was used to determine the content of bacterial endotoxins in Panax notoginseng saponins solution before and after using the ultrafiltration. The change of the contents of active components was examined by HPLC,using notoginsennoside R1, ginsennoside Rg1, ginsennoside Rb1 and ginsennoside Rd as the mark components. RESULTS: The removal rate of bacterial endotoxin fell along with the increasing of membrane aperture. The removal rate was 20. 69% by ultrafiltration membranes of 100 KDa with polysulfone material,less than those of other ultrafiltration membranes with polysulfone material. But the removal rate of bacterial endotoxin by E membranes of blend materials was higher than those of other ultrafiltration membranes with polysulfone material. The contents of active components filtered by E membranes of blend materials was more than that of ultrafiltration membranes of 100 KDa with polysulfone material. CONCLUSION: The applicability of ultrafiltration membranes of large cut-off molecular weight and blend materials of effectual component in Panax notoginseng saponins and elimination of pyrogen is good.