Investigating the efficacy of an exopolysaccharide (EPS)-producing strain Lactiplantibacillus plantarum L75 on oat silage fermentation at different temperatures

This study investigates the effectiveness of an exopolysaccharide (EPS)-producing strain (Lactiplantibacillus plantarum L75) alone or in combination with Saccharomyces cerevisiae on the fermentation characteristics, antioxidant capacities and microbial community successions of oat silage stored at various temperatures. A rapid decrease in pH and lactic acid accumulation was observed in silages treated with L. plantarum and S. cerevisiae (LS) as early as 3 days of ensiling (p < 0.05). Over the ensiling period of 7-60 days, L. plantarum (L)-inoculated groups showed the lowest pH, lowest ammonia nitrogen and the highest amount of lactic acid regardless of the storage temperatures. When the oat silage was stored at 15°C, LS-inoculated group exhibited a higher superoxide dismutase (SOD) activity than control and L-inoculated group. Furthermore, the proportion of Lactiplantibacillus in the combined inoculation group increased by 65.42% compared to the L-inoculated group (33.26%). Fungal community data revealed abundant Penicillium carneum in the control and L-inoculated groups stored at 15°C. Conclusively, these results showed that combined inoculation of L. plantarum L75 and S. cerevisiae improved the fermentation quality of oat silage at 15°C, thus proposing a technique for enhancing the fermentation quality of silage in regions with low temperatures during harvest season.

Disassembly of the TRIM56-ATR complex promotes cytoDNA/cGAS/STING axis-dependent intervertebral disc inflammatory degeneration

As the leading cause of disability worldwide, low back pain (LBP) is recognized as a pivotal socioeconomic challenge to the aging population and is largely attributed to intervertebral disc degeneration (IVDD). Elastic nucleus pulposus (NP) tissue is essential for the maintenance of IVD structural and functional integrity. The accumulation of senescent NP cells with an inflammatory hypersecretory phenotype due to aging and other damaging factors is a distinctive hallmark of IVDD initiation and progression. In this study, we reveal a mechanism of IVDD progression in which aberrant genomic DNA damage promoted NP cell inflammatory senescence via activation of the cyclic GMP-AMP synthase/stimulator of IFN genes (cGAS/STING) axis but not of absent in melanoma 2 (AIM2) inflammasome assembly. Ataxia-telangiectasia-mutated and Rad3-related protein (ATR) deficiency destroyed genomic integrity and led to cytosolic mislocalization of genomic DNA, which acted as a powerful driver of cGAS/STING axis-dependent inflammatory phenotype acquisition during NP cell senescence. Mechanistically, disassembly of the ATR-tripartite motif-containing 56 (ATR-TRIM56) complex with the enzymatic liberation of ubiquitin-specific peptidase 5 (USP5) and TRIM25 drove changes in ATR ubiquitination, with ATR switching from K63- to K48-linked modification, c thereby promoting ubiquitin-proteasome-dependent dynamic instability of ATR protein during NP cell senescence progression. Importantly, an engineered extracellular vesicle-based strategy for delivering ATR-overexpressing plasmid cargo efficiently diminished DNA damage-associated NP cell senescence and substantially mitigated IVDD progression, indicating promising targets and effective approaches to ameliorate the chronic pain and disabling effects of IVDD.

Responses of microbial community dynamics, co-occurrences, functional shifts, and natural fermentation profiles of Elymus nutans silage to altitudinal gradients

IMPORTANCE

On the Qinghai-Tibet Plateau (QTP), feed shortages are common due to cold environmental conditions and the short growing season of crops. Therefore, effective preservation, such as the ensiling of local forage, is becoming increasingly important to balance the seasonal imbalance between the forage supply and the nutritional needs of domestic animals in this area. However, the structure of the microbial community of the forage, which is influenced by climatic conditions such as altitude differences, has a major impact on the fermentation quality and microbial succession of the ensiled forage. Therefore, we investigated microbial community dynamics, co-occurrence, functional shifts, and natural fermentation profiles of Elymus nutans silage as a function of altitudinal gradients. Results show that silage from Chenduo at higher elevations has better fermentation quality and higher abundance of Lacticaseibacillus and Levilactobacillus than ensiled forage from other regions. This work may contribute to guiding for silage production in QTP.

Effect of endogenous sodium and potassium ions in plants on the quality of alfalfa silage and bacterial community stability during fermentation

This study investigated the impact of endogenous sodium and potassium ions in plants on the quality of alfalfa silage, as well as the stability of bacterial communities during fermentation. Silage was produced from the fermented alfalfa, and the chemical composition, fermentation characteristics, and microbiome were analyzed to understand their interplay and impact on silage fermentation quality. The alfalfa was cultivated under salt stress with the following: (a) soil content of <1‰ (CK); (b) 1‰-2‰ (LP); (c) 2‰-3‰ (MP); (d) 3‰-4‰ (HP). The results revealed that the pH of silage was negatively correlated with the lactic acid content. With the increase of lactic acid (LA) content increased (26.3-51.0 g/kg DM), the pH value decreased (4.9-5.3). With the increase of salt stress, the content of Na+ in silage increased (2.2-5.4 g/kg DM). The presence of endogenous Na+ and K+ ions in plants significantly affected the quality of alfalfa silage and the dynamics of bacterial communities during fermentation. Increased salt stress led to changes in microbial composition, with Lactococcus and Pantoea showing a gradual increase in abundance, especially under high salt stress. Low pH inhibited the growth of certain bacterial genera, such as Pantoea and Pediococcus. The abundance of Escherichia-Shigella and Comamonas negatively correlated with crude protein (CP) content, while Enterococcus and Lactococcus exhibited a positive correlation. Furthermore, the accumulation of endogenous Na+ in alfalfa under salt stress suppressed bacterial proliferation, thereby reducing protein degradation during fermentation. The pH of the silage was high, and the LA content was also high. Silages from alfalfa under higher salt stress had higher Na+ content. The alpha diversity of bacterial communities in alfalfa silages showed distinct patterns. Desirable genera like Lactococcus and Lactobacillus predominated in silages produced from alfalfa under salt stress, resulting in better fermentation quality.

Selective cargo sorting in stem cell-derived small extracellular vesicles: impact on therapeutic efficacy for intervertebral disc degeneration

BACKGROUND

Growing evidence has suggested the role of stem cell-derived small extracellular vesicles (sEVs) in intervertebral disc degeneration (IVDD). The cargo sorting of sEVs, particularly miRNAs, may be influenced when the donor cell is subjected to oxidative stress. Here, we discovered that miRNAs containing specific motifs are selectively sorted into intraluminal vesicles within mesenchymal stem cells (MSCs) in response to oxidative stress.

METHODS

Analysis of miRNA cargoes in sEVs derived from normal MSCs (C-sEVs) or stressed MSCs (T-sEVs) was conducted using miRNA sequencing. Differential expressed miRNAs in sEVs and the identification of motifs were evaluated through bioinformatics analysis. Protein binding was assessed using immunofluorescent staining and immunoprecipitation analysis. Additionally, RNA pull down and RNA immunoprecipitation (RIP) immunoprecipitation were employed to determine the binding between miRNAs and proteins. The effects of C-sEVs and T-sEVs on IVDD were compared by detecting the expression levels of phenotypic genes in vitro or histological evaluation in vivo.

RESULTS

The sorting process of miRNAs is mediated by the nucleocytoplasmic transport of heterogeneous nuclear ribonucleoproteins, which in turn facilitates the phosphorylation of SNAP25 and promotes the transport and secretion of sEVs. Additionally, CHMP1B plays a role in membrane repair and protects against cell ferroptosis upon oxidative stress, concurrently affecting the release of sEVs. Notably, stem cell-derived sEVs associated with ferroptosis impair the therapeutic efficacy for IVDD. However, the application of engineered sEVs containing a specific miRNA inhibitor exhibits the potential to reinstate the therapeutic efficacy for IVDD both in vitro and in vivo.

CONCLUSIONS

Taken together, our findings shed light on the mechanism of miRNAs sorting into sEVs and offer new insights for the optimization of sEV-based treatments during intervertebral disc regeneration. regeneration.

Sequential Correction versus Conventional Correction for Severe and Rigid Kyphoscoliosis: A Retrospective Case Control Study

OBJECTIVE

Conventional correction techniques were challenging and of high risk of neurological complications for the correction of severe and rigid kyphoscoliosis. A new technical note we developed and named as sequential correction, was used to treat severe and rigid kyphoscoliosis. The present study was to compare the clinical outcomes of sequential correction versus conventional correction for the treatment of severe and rigid kyphoscoliosis.

METHODS

This is a respectively case-control study. Between January 2014 and December 2019, 36 adults underwent the surgical correction of severe and rigid kyphoscoliosis and were included in the present study. Among them, 20 adults underwent conventional correction, 16 adults underwent sequential correction. Major curve Cobb angle, kyphotic angle, coronal imbalance, and sagittal vertical axis were compared between two groups. The patient-reported health-related quality of life outcomes, including the Oswestry disability index score, and SRS-22 questionnaire, were recorded. Independent samples t-test, Mann-Whitney U test, and Wilcoxon signed-rank test, were used to compare the differences between two groups according to the results of normal distribution test.

RESULTS

In conventional correction group, the mean major curve Cobb angle was 122.50° preoperatively, 40.35° immediately after surgery, and 43.95° at final follow-up postoperatively; the mean kyphotic angle was 97.45° preoperatively, 34.45° immediately after surgery, and 38.30° at final follow-up postoperatively. In the sequential correction group, the mean major angle was 134.44° preoperatively, 44.56° immediately after surgery, and 46.25° at final follow-up postoperatively; the mean kyphotic angle was 112.31° preoperatively, 39.00° immediately after surgery, and 40.38° at final follow-up postoperatively. The mean major curve Cobb angle and kyphotic angle of both groups were improved significantly, while there were no significant differences between two groups (p > 0.001). Improved self-reported quality of life scores were achieved postoperatively and at final follow-up postoperatively, and there were no significant differences between the two groups. The total complication rate of the patients underwent conventional correction was 55%, and the total complication rate of the patients underwent sequential correction was 43.75%. The complication rate of the two groups showed no significant difference.

CONCLUSIONS

Sequential correction is an excellent and safe treatment for severe and rigid kyphoscoliosis in adults, with similar clinical outcomes with conventional correction. The total complication rate of the patients who underwent sequential correction was slightly lower than conventional correction.

Matrix stiffness induces Drp1-mediated mitochondrial fission through Piezo1 mechanotransduction in human intervertebral disc degeneration

BACKGROUND

Extracellular matrix stiffness is emerging as a crucial mechanical cue that drives the progression of various diseases, such as cancer, fibrosis, and inflammation. The matrix stiffness of the nucleus pulposus (NP) tissues increase gradually during intervertebral disc degeneration (IDD), while the mechanism through which NP cells sense and react to matrix stiffness remains unclear. In addition, mitochondrial dynamics play a key role in various cellular functions. An in-depth investigation of the pathogenesis of IDD can provide new insights for the development of effective therapies. In this study, we aim to investigate the effects of matrix stiffness on mitochondrial dynamics in IDD.

METHODS

To build the gradient stiffness model, NP cells were cultured on polystyrene plates with different stiffness. Western blot analysis, and immunofluorescence staining were used to detect the expression of mitochondrial dynamics-related proteins. Flow cytometry was used to detect the mitochondrial membrane potential and intracellular Ca2+ levels. Apoptosis related proteins, ROS level, and TUNEL staining were performed to assess the effect of substrate stiffness on NP cells.

RESULTS

Stiff substrate increased phosphorylation of dynamin-related protein 1 (Drp1) at Ser616 by activating extracellular signal-regulated kinase 1/2 (ERK1/2) pathway, which promoted mitochondrial fission and apoptosis in NP cells. Furthermore, Piezo1 activation was involved in the regulation of the post-translational modifications of Drp1 and mitochondrial fission caused by matrix stiffness. Inhibition of Piezo1 and ERK1/2 can effectively reduce stiffness-induced ROS elevation and apoptosis in NP cells.

CONCLUSIONS

Our results revealed that stiff substrate causes Piezo1 activation and Ca2+ influx, results in ERK1/2 activation and phosphorylation of Drp1 at S616, and finally leads to mitochondrial fission and apoptosis in NP cells. These findings reveal a new mechanism of mechanotransduction in NP cells, providing novel insights into the development of therapies for treating IDD.

Comprehensive profiling of the metabolome in corn silage inoculated with or without Lactiplantibacillus plantarum using different untargeted metabolomics analyses

Silage fermentation is a complicated biochemical process involving interactions between microbes and metabolites. However, the overall metabolome feature of ensiled forage and its response to lactic acid bacteria inoculation is poorly understood. Hence, in this study metabolome profiles of whole-plant corn silage inoculated with or without Lactiplantibacillus plantarum were characterised via solid-phase microextraction/gas chromatography/mass spectrometry (SPME-GC-MS), gas chromatography/time-of-flight mass spectrometry (GC-TOF-MS), and Liquid chromatography/Q Exactive HFX mass spectrometry (LC-QE-MS/MS) analysis. There were 2087 identified metabolites including 1143 reliably identified metabolites in fresh and ensiled whole-plant corn. After ensiling, the increased metabolites in whole-plant corn were mainly composed of organic acids, volatile organic compounds (VOC), benzene and substituted derivatives, carboxylic acids and derivatives, fatty acyls, flavonoids, indoles and derivatives, organooxygen compounds (including amines and amides), phenols, pyridines and derivatives, and steroids and steroid derivatives, which includes neurotransmitters and metabolites with aromatic, antioxidant, anti-inflammatory, and antimicrobial activities. Phenylacetaldehyde was the most abundant aromatic metabolite after ensiling. L-isoleucine and oxoproline were the major free amino acids in silage. Ensiling markedly increased the relative abundances of 3-phenyllactic acid, chrysoeriol, 6-O-acetylaustroinulin, acetylcholine, γ-aminobutyric acid, pyridoxine, and alpha-linoleic acid. Inoculation with L. plantarum remarkably changed silage VOC composition, and essential amino acids, 3-phenyllactic acid, and cinnamaldehyde compared with untreated silage. The present study does not only provide a deeper insight into metabolites of the ensiled whole-plant corn but also reveals metabolites with specific biological functions that could be much helpful in screening novel lactic acid bacteria to well ensile forages. Inoculation with L. plantarum significantly affects the metabolome in ensiled whole-plant corn.

Biomechanical Comparison of Different Surgical Approaches for the Treatment of Adjacent Segment Diseases after Primary Transforaminal Lumbar Interbody Fusion: A Finite Element Analysis

BACKGROUND AND OBJECTIVE

Adjacent segment disease (ASD) is a well-known complication after interbody fusion. Revision surgery is necessary for symptomatic ASD to further decompress and fix the affected segment. However, no optimal construct is accepted as a standard in treating ASD. The purpose of this study was to compare the biomechanical effects of different surgical approaches for the treatment of ASD after primary transforaminal lumbar interbody fusion (TLIF).

METHODS

A finite element model of the L1-S1 was conducted based on computed tomography scan images. The primary surgery model was developed with a single-level TLIF at L4-L5 segment. The revision surgical models were developed with anterior lumbar interbody fusion (ALIF), lateral lumbar interbody fusion (LLIF), or TLIF at L3-L4 segment. The range of motion (ROM), intradiscal pressure (IDP), and the stress in cages were compared to investigate the biomechanical influences of different surgical approaches.

RESULTS

The results indicated that all the three surgical approaches can stabilize the spinal segment by reducing the ROM at revision level. The ROM and IDP at adjacent segments of revision model of TLIF was greater than those of other revision models. While revision surgery with ALIF and LLIF had similar effects on the ROM and IDP of adjacent segments. Compared among all the surgical models, cage stress in revision model of TLIF was the maximum in extension and axial rotation.

CONCLUSION

The IDP at adjacent segments and stress in cages of revision model of TLIF was greater than those of ALIF and LLIF. This may be that direct extension of the surgical segment in the same direction results in stress concentration.

Stiff Substrate Induces Nucleus Pulposus Cell Ferroptosis via YAP and N-Cadherin Mediated Mechanotransduction

Increased tissue stiffness is associated with various pathological processes, such as fibrosis, inflammation, and aging. The matrix stiffness of the nucleus pulposus (NP) tissues increases gradually during intervertebral disc degeneration (IDD), while the mechanism through which NP cells sense and react to matrix stiffness remains unclear. In this study, the results indicate that ferroptosis is involved in stiff substrate-induced NP cell death. The expression of acyl-CoA synthetase long-chain family member 4 (ACSL4) increases in NP cells of the stiff group, which mediates lipid peroxidation and ferroptosis in NP cells. In addition, stiff substrate activates the hippo signaling cascade and induces the nuclear translocation of yes-associated protein (YAP). Interestingly, inhibition of YAP is efficient to reverse the increase of ACSL4 expression caused by matrix stiffness. Furthermore, stiff substrate suppresses the expression of N-cadherin in NP cells. N-cadherin overexpression can inhibit YAP nuclear translocation via the formation of the N-cadherin/β-catenin/YAP complex, and reverse matrix stiffness-induced ferroptosis in NP cells. Finally, the effects of YAP inhibition and N-cadherin overexpression on IDD progression are further illustrated in animal models. These findings reveal a new mechanism of mechanotransduction in NP cells, providing novel insights into the development of therapies for the treatment of IDD.

Dry matter content and inoculant alter the metabolome and bacterial community of alfalfa ensiled at high temperature

Alfalfa silage fermentation quality, metabolome, bacterial interactions, and successions as well as their predicted metabolic pathways were explored under different dry matter contents (DM) and lactic acid bacteria (LAB) inoculations. Silages were prepared from alfalfa with DM contents of 304 (LDM) and 433 (HDM) g/kg fresh weight and inoculated with Lactiplantibacillus plantarum (L. plantarum, LP), Pediococcus pentosaceus (P. pentosaceus, PP), or sterile water (control). The silages were stored at a simulated hot climate condition (35°C) and sampled at 0, 7, 14, 30, and 60 days of fermentation. The results revealed that HDM significantly improved the alfalfa silage quality and altered microbial community composition. The GC-TOF-MS analysis discovered 200 metabolites in both LDM and HDM alfalfa silage, mainly consisting of amino acids, carbohydrates, fatty acids, and alcohols. Compared with LP and control, PP-inoculated silages had increased concentrations of lactic acid (P < 0.05) and essential amino acids (threonine and tryptophan) as well as decreased pH, putrescine content, and amino acid metabolism. However, alfalfa silage inoculated with LP had higher proteolytic activities than control and PP-inoculated silage, as revealed by a higher concentration of ammonia nitrogen (NH₃-N), and also upregulated amino acid and energy metabolism. HDM content and P. pentosaceus inoculation significantly altered the composition of alfalfa silage microbiota from 7 to 60 days of ensiling. Conclusively, these results indicated that inoculation with PP exhibited great potential in enhancing the fermentation of silage with LDM and HDM via altering the microbiome and metabolome of the ensiled alfalfa, which could help in understanding and improving the ensiling practices under hot climate conditions. KEY POINTS: • HDM improved fermentation quality and declined putrescine content of alfalfa silage • P. pentosaceus inoculation enhanced the fermentation quality of alfalfa silage • P. pentosaceus is an ideal inoculant for alfalfa silage under high temperature.

Effects of Bacillus coagulans and Lactobacillus plantarum on the Fermentation Characteristics, Microbial Community, and Functional Shifts during Alfalfa Silage Fermentation

This study aimed to investigate the potential of Bacillus coagulans (BC) as an inoculant in alfalfa silage fermentation. Fresh alfalfa was harvested at a dry matter (DM) content of 329.60 g/kg fresh weight (FW), and inoculated without (CON) or with BC (1 × 10⁶ CFU/g FW), Lactobacillus plantarum (LP, 1 × 10⁶ CFU/g FW), and their combinations (LP+BC, 1 × 10⁶ CFU/g FW, respectively). Samples were taken at 3, 7, 14, 30, and 60 d, with three replicates for each. The prolonged ensiling period resulted in a decrease in pH values and an increase in lactic acid (LA) concentrations in alfalfa silages. After 60 d of fermentation, the application of BC and LP decreased the pH values and increased LA concentrations in treated silages, especially when their combination was applied. Application of BC preserved more water-soluble carbohydrates (WSC), and further application of BC increased WSC in LP+BC-treated silage compared to LP-treated silage. There was no significant difference in the crude protein (CP) content between the CON and treated silages, however, the BC and LP treatments reduced the ammonia nitrogen (NH₃-N) concentration, especially when their combination was applied. Additionally, the BC and LP-treated silages had lower neutral detergent fiber (NDF) and acid detergent fiber (ADF) when compared to the CON silage (p < 0.001). Inoculants also increased Lactobacillus abundance and decreased Enterococcus abundance after 60 d of fermentation. Spearman's rank correlation analysis revealed a positive correlation between LA concentration and Lactobacillus abundance. It was noteworthy that LP, BC, and their combination increased the relative abundances of carbohydrate metabolism, energy metabolism, cofactors, and vitamin metabolism, decreasing the relative abundances of amino acid metabolism and drug resistance: antimicrobial. Therefore, the inclusion of BC increased the fermentation quality of alfalfa silage, with the optimal combination being LP+BC. According to the findings, BC could be considered a viable bioresource for improving fermentation quality.

Augmenting Intracellular Cargo Delivery of Extracellular Vesicles in Hypoxic Tissues through Inhibiting Hypoxia-Induced Endocytic Recycling

As mesenchymal stem-cell-derived small extracellular vesicles (MSC-sEVs) have been widely applied in treatment of degenerative diseases, it is essential to improve their cargo delivery efficiency in specific microenvironments of lesions. However, the interaction between the microenvironment of recipient cells and MSC-sEVs remains poorly understood. Herein, we find that the cargo delivery efficiency of MSC-sEVs was significantly reduced under hypoxia in inflammaging nucleus pulposus cells due to activated endocytic recycling of MSC-sEVs. Hypoxia-inducible factor-1 (HIF-1)-induced upregulated RCP (also known as RAB11FIP1) is shown to promote the Rab11a-dependent recycling of internalized MSC-sEVs under hypoxia via enhancing the interaction between Rab11a and MSC-sEV. Based on this finding, si-RCP is loaded into MSC-sEVs using electroporation to overcome the hypoxic microenvironment of intervertebral disks. The engineered MSC-sEVs significantly inhibit the endocytic recycling process and exhibit higher delivery efficiency under hypoxia. In a rat model of intervertebral disk degeneration (IDD), the si-RCP-loaded MSC-sEVs successfully treat IDD with improved regenerative capacity compared with natural MSC-sEV. Collectively, the findings illustrate the intracellular traffic mechanism of MSC-sEVs under hypoxia and demonstrate that the therapeutic capacity of MSC-sEVs can be improved via inhibiting endocytic recycling. This modifying strategy may further facilitate the application of extracellular vesicles in hypoxic tissues.

Small extracellular vesicles with nanomorphology memory promote osteogenesis

Nanotopographical cues endow biomaterials the ability to guide cell adhesion, proliferation, and differentiation. Cellular mechanical memory can maintain the cell status by retaining cellular information obtained from past mechanical microenvironments. Here, we propose a new concept “morphology memory of small extracellular vesicles (sEV)” for bone regeneration. We performed nanotopography on titanium plates through alkali and heat (Ti8) treatment to promote human mesenchymal stem cell (hMSC) differentiation. Next, we extracted the sEVs from the hMSC, which were cultured on the nanotopographical Ti plates for 21 days (Ti8-21-sEV). We demonstrated that Ti8-21-sEV had superior pro-osteogenesis ability in vitro and in vivo. RNA sequencing further confirmed that Ti8-21-sEV promote bone regeneration through osteogenic-related pathways, including the PI3K-AKT signaling pathway, MAPK signaling pathway, focal adhesion, and extracellular matrix-receptor interaction. Finally, we decorated the Ti8-21-sEV on a 3D printed porous polyetheretherketone scaffold. The femoral condyle defect model of rabbits was used to demonstrate that Ti8-21-sEV had the best bone ingrowth. In summary, our study demonstrated that the Ti8-21-sEV have memory function by copying the pro-osteogenesis information from the nanotopography. We expect that our study will encourage the discovery of other sEV with morphology memory for tissue regeneration.

•

Nanotopography fabricated on titanium plates has superior promoted hMSCs differentiation ability.

•

sEV extracted from hMSCs which were cultured on Ti8 plates for 21 days had the superior pro-osteogenesis ability.

•

Ti8-21-sEV have memory function through copy the pro-osteogenesis information from nanotopography.

•

RNA sequencing confirmed that Ti8-21-sEV promote bone regeneration through osteogenic-related pathways.

Vasorin-containing small extracellular vesicles retard intervertebral disc degeneration utilizing an injectable thermoresponsive delivery system

Intervertebral disc degeneration (IDD) is the pathological reason of back pain and the therapeutic approaches are still unsatisfactory. Recently, mesenchymal stem cell-derived small extracellular vesicles (EVs) have emerged as the novel regenerative method for IDD. In this study, we intensively investigated the therapeutic mechanism of small EVs, and found that vasorin protein enriched in EVs promoted the proliferation and extracellular matrix anabolism of nucleus pulposus cells via the Notch1 signaling pathway. Then, we fabricated a thermoresponsive gel which composed of Pluronic F127 and decellularized extracellular matrix (FEC) for the delivery and sustained release of EVs. Besides, ex vivo and in vivo results showed that EVs embedded in FEC (EVs@FEC) ameliorate the disc degeneration efficiently and achieve better therapeutic effects than one-off EVs delivery. Collectively, these findings deepen the understanding of EVs mechanism in treating intervertebral disc degeneration, and also illustrate the promising capacity of sustained EVs release system for intervertebral disc regeneration.

O-GlcNAc transferase regulates intervertebral disc degeneration by targeting FAM134B-mediated ER-phagy

Both O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) and endoplasmic reticulum-phagy (ER-phagy) are well-characterized conserved adaptive regulatory mechanisms that maintain cellular homeostasis and function in response to various stress conditions. Abnormalities in O-GlcNAcylation and ER-phagy have been documented in a wide variety of human pathologies. However, whether O-GlcNAcylation or ER-phagy is involved in the pathogenesis of intervertebral disc degeneration (IDD) is largely unknown. In this study, we investigated the function of O-GlcNAcylation and ER-phagy and the related underlying mechanisms in IDD. We found that the expression profiles of O-GlcNAcylation and O-GlcNAc transferase (OGT) were notably increased in degenerated NP tissues and nutrient-deprived nucleus pulposus (NP) cells. By modulating the O-GlcNAc level through genetic manipulation and specific pharmacological intervention, we revealed that increasing O-GlcNAcylation abundance substantially enhanced cell function and facilitated cell survival under nutrient deprivation (ND) conditions. Moreover, FAM134B-mediated ER-phagy activation was regulated by O-GlcNAcylation, and suppression of ER-phagy by FAM134B knockdown considerably counteracted the protective effects of amplified O-GlcNAcylation. Mechanistically, FAM134B was determined to be a potential target of OGT, and O-GlcNAcylation of FAM134B notably reduced FAM134B ubiquitination-mediated degradation. Correspondingly, the protection conferred by modulating O-GlcNAcylation homeostasis was verified in a rat IDD model. Our data demonstrated that OGT directly associates with and stabilizes FAM134B and subsequently enhances FAM134B-mediated ER-phagy to enhance the adaptive capability of cells in response to nutrient deficiency. These findings may provide a new option for O-GlcNAcylation-based therapeutics in IDD prevention.

A cellular ‘housekeeping’ mechanism that counters the detrimental effects of stress could also help protect against lower back pain by preventing degeneration of the spongy discs that cushion our vertebrae. When subjected to traumatic conditions such as nutrient deprivation, some cells respond by breaking down excess components of an intracellular organelle, the endoplasmic reticulum (ER). Researchers led by Yu Song and Cao Yang at Huazhong University of Science and Technology, Wuhan, China, have shown that this ‘ER-phagy’ response helps promote the survival of stressed nucleus pulposus (NP) cells, the inner core of intravertebral discs. Cultured human NP cells tend to die off in starvation conditions, but were sustained by activation of ER-phagy pathways. This same mechanism was shown to prevent disc degeneration in rats, suggesting a potential therapeutic strategy for preventing lower back pain in humans.

Bone Repairment via Mechanosensation of Piezo1 Using Wearable Pulsed Triboelectric Nanogenerator

Bone repair in real time is a challenging medical issue for elderly patients; this is mainly because aged bone marrow mesenchymal stem cells (BMSCs) possess limited osteogenesis potential and repair capacity. In this study, triboelectric stimulation technology is used to achieve bone repair via mechanosensation of Piezo1 by fabricating a wearable pulsed triboelectric nanogenerator (WP-TENG) driven by human body movement. A peak value of 30 µA has the optimal effects to rejuvenate aged BMSCs, enhance their osteogenic differentiation, and promote human umbilical vein endothelial cell tube formation. Further, previous studies demonstrate that triboelectric stimulation of a WP-TENG can reinforce osteogenesis of BMSCs and promote the angiogenesis of human umbilical vein endothelial cells (HUVECs). Mechanistically, aged BMSCs are rejuvenated by triboelectric stimulation via the mechanosensitive ion channel Piezo1. Thus, the osteogenesis potential of BMSCs is enhanced and the tube formation capacity of HUVECs is improved, which is further confirmed by augmented bone repair and regeneration in in vivo investigations. This study provides a potential signal transduction mechanism for rejuvenating aged BMSCs and a theoretical basis for bone regeneration using triboelectric stimulation generated by a WP-TENG.

Distal adding-on after surgery in Lenke 5C adolescent idiopathic scoliosis: clinical and radiological outcomes

Background

To evaluate the incidence and risk factors of postoperative distal adding-on in patients with Lenke 5C adolescent idiopathic scoliosis (AIS). More accurate selection criteria for the lower instrumented vertebra (LIV) should be confirmed to prevent distal adding-on.

Methods

Forty-six patients with Lenke 5C AIS who underwent posterior fusion were enrolled in the study. Patients were allocated into adding-on and no adding-on groups. Demographic data, clinical data, and radiographic parameters were recorded and compared.

Results

Postoperative distal adding-on occurred in eight patients (17.4%) during follow-up. Demographic data, clinical data, and baseline radiographic parameters of the two groups were not significantly different. The postoperative thoracolumbar (TL) or lumbar (L) Cobb angle, LIV translation, and LIV + 1 translation were higher in the adding-on group than those in the no adding-on group, while the postoperative coronal imbalance of the adding-on group was lower than that of the no adding-on group. The level difference of last barely touched vertebra (LBTV) and last substantial touched vertebra (LSTV) with LIV were higher in the adding-on group than in the no adding-on group.

Conclusion

Postoperative TL/L curve, postoperative LIV translation, postoperative LIV + 1 translation, and postoperative coronal imbalance were determined as risk factors for postoperative distal adding-on in patients with Lenke 5C AIS. Moreover, LIV selection of LBTV-1 or LSTV-1 may cause a higher risk of postoperative distal adding-on.

Evaluation of the Radiographic Risk Factors of Postoperative Shoulder Imbalance in Adult Scoliosis

Objective

This study aimed to evaluate the radiographic risk factors of postoperative shoulder imbalance (PSI) after adult scoliosis (AS) correction surgery.

Methods

Seventy-nine patients with AS undergoing correction surgery at a single institution were reviewed. The mean follow-up was 28 months. Patients were divided into two groups based on their radiographic shoulder height (RSH): (1) the balanced group (RSH <10 mm) and (2) the unbalanced group (RSH ≥10 mm). The preoperative and postoperative Cobb angles of the proximal thoracic (PT), main thoracic (MT), thoracolumbar/lumbar (TL/L) and upper instrumented vertebra (UIV) were measured.

Results

No significant difference was found between the balanced and unbalanced groups when the UIV was T1–2, T3–4, or below T4. Univariate analysis indicated that the unbalanced group had significantly higher postoperative RSH, lower percentage PT correction, and greater percentage MT correction. The classification and regression tree analysis revealed that when the correction percentage of PT curve was more than 55.3%, 84.4% of patients acquired shoulder balance. However, when the correction percentage of PT curve was less than 55.3%, and the correction percentage of MT curve was more than 56%, 65.7% of the patients developed PSI.

Conclusions

In AS correction surgery, a lower percentage correction of the PT curve and greater percentage correction of the MT curve were independent radiographic risk factors of PSI, regardless of the UIV level. Sufficient PT correction is required to achieve postoperative shoulder balance in AS correction surgery when the MT curve is overcorrected.

Microbial mechanisms of using feruloyl esterase-producing Lactobacillus plantarum A1 and grape pomace to improve fermentation quality and mitigate ruminal methane emission of ensiled alfalfa for cleaner animal production

This study was conducted to investigate the influence of feruloyl esterase-producing Lactobacillus plantarum A1 (Lp A1) and grape pomace (GP) alone, or in combination (LG) on ensiling characteristics and bacterial community, in vitro ruminal fermentation, methane (CH₄) emission, and the microbiota of ensiled alfalfa. Alfalfa at 42% dry matter (DM) was treated in a 2 × 2 factorial design: with the application of Lp A1 at 0 (control) or 1 × 10⁶ cfu/g of fresh forage, and GP at 0 or 5% of fresh forage. After 60 d of ensiling, a decrease in nonprotein nitrogen (NPN) was observed in GP treated silage. Lp A1 inoculated silage had a lower fiber content than silages without Lp A1. The lowest NPN was found in silage treated with LG, and an obvious increase in the relative abundance of Lactobacillus paracasei was detected in silages treated with Lp A1 and LG, respectively. In vitro ruminal experiments indicated that, although the application of GP deceased ruminal total gas, CH₄ production, nitrogen degradation and the number of methanogenic archaea in alfalfa silage, it also reduced silage DM digestibility. In contrast, inoculation with Lp A1 not only increased DM digestibility and populations of ruminal Ruminococcus flavefaciens and fungi, but also improved ruminal total gas and CH₄ production. As expected, LG treatment decreased alfalfa silage ruminal total gas and CH₄ production relative to Lp A1 treatment alone, and increased silage DM digestibility compared with GP treated silage. In conclusion, the application of LG before ensiling alfalfa, balanced silage proteolysis, feed digestibility, and CH₄ emission, and could be a promising strategy for using food industry by-products to produce a nutritional and environmentally-friendly legume silage that will mitigate N and greenhouse gas emissions from ruminants.

WTAP-mediated m6A modification of lncRNA NORAD promotes intervertebral disc degeneration

N6-methyladenosine (m⁶A) is the most prevalent RNA modification at the posttranscriptional level and involved in various diseases and cellular processes. However, the underlying mechanism of m⁶A regulation in intervertebral disc degeneration (IVDD) remains elusive. Here, we show that methylation of the lncRNA NORAD significantly increases in senescent nucleus pulposus cells (NPCs) by m⁶A sequencing. Subsequent loss- and gain-of-function experiments reveal WTAP is increased in senescent NPCs due to an epigenetic increase in H3K4me3 of the promoter mediated by KDM5a, and significantly promotes NORAD m⁶A modification. Furthermore, YTHDF2-mediated decay of NORAD is enhanced in senescent NPCs, and then deficiency of NORAD results in less sequestraion of PUMILIO proteins, contributing to the augmented activity of PUM1/2, thus repressing the expression of target E2F3 mRNAs and promoting the cellular senescence. Here, we show interruption of NORAD m⁶A modification or the NORAD/PUMILIO/E2F3 axis could serve as a potential therapeutic target to inhibit the senescence of NPCs and development of IVDD.

Intervertebral disc degeneration (IVDD) is the leading cause of low back pain and Nucleus pulposus cell senescence contributes a lot to its progression. Here, the authors reveal WTAP-mediated m6A modification of lncRNA NORAD promotes IVDD.

m6A hypomethylation of DNMT3B regulated by ALKBH5 promotes intervertebral disc degeneration via E4F1 deficiency

BACKGROUND

The intervertebral disc (IVD) degeneration is the leading cause of low back pain, which accounts for a main cause of disability. N6-methyladenosine (m6A) is the most abundant internal modification in eukaryotic messenger RNAs and is involved in various diseases and cellular processes by modulating mRNA fate. However, the critical role of m6A regulation in IVD degeneration remains unclear. Nucleus pulposus cell (NPC) senescence is critical for the progression of IVD degeneration. Here, we uncovered the role and explored the regulatory mechanism of m6A in NPC senescence during IVD degeneration.

METHODS

Identification of NPC senescence during IVD degeneration was based on the analysis of tissue samples and the cellular model. ALKBH5 upregulation inducing cellular senescence was confirmed by functional experiments in vivo and in vitro. ChIP-qPCR and DNA-Pulldown were used to reveal increased ALKBH5 was regulated by KDM4A-mediated H3K9me3. Furthermore, Me-RIP-seq was performed to identify m6A hypomethylation of DNMT3B transcripts in senescent NPCs. Stability analysis showed that DNMT3B expression was enhanced for less YTHDF2 recognition and increased DNMT3B promoted NPC senescence and IVD degeneration via E4F1 methylation by in vivo and in vitro analyses.

RESULTS

Expression of ALKBH5 is enhanced during IVD degeneration and NPC senescence, due to decreased KDM4A-mediated H3K9me3 modification. Functionally, ALKBH5 causes NPC senescence by demethylating DNMT3B transcripts and in turn promoting its expression via less YTHDF2 recognition and following degradation due to transcript hypomethylation in vitro and in vivo. Increased DNMT3B promotes the development of IVD degeneration and NPC senescence, mechanistically by methylating CpG islands of E4F1 at the promoter region and thus restraining its transcription and expression.

CONCLUSIONS

Collectively, our findings reveal an epigenetic interplay mechanism in NPC senescence and IVD degeneration, presenting a critical pro-senescence role of ALKBH5 and m6A hypomethylation, highlighting the therapeutic potential of targeting the m6A/DNMT3B/E4F1 axis for treating IVD degeneration.

Characterization of a novel beta-cypermethrin-degrading strain of Lactobacillus pentosus 3-27 and its effects on bioremediation and the bacterial community of contaminated alfalfa silage

In this study, a novel beta-cypermethrin (beta-cyp)-degrading strain Lactobacillus pentosus 3-27 (LP3-27) was screened from beta-cyp-contaminated silage. The strain could degrade 96% of beta-cyp (50 mg/L) in MSM medium after 4 d of culture, while the strain lost its degradation ability when the beta-cyp concentration reached 250 mg/L. The effects of LP 3-27 on fermentation, bacterial community, and bioremediation of contaminated alfalfa silage at two dry matter (DM) contents were studied. The results showed that inoculation with LP3-27 not only degraded beta-cyp, but also improved the fermentation quality of alfalfa silage after 60 d of ensiling. Meanwhile, L. pentosus dominated the bacterial community during ensiling in LP3-27 inoculated silages, whereas Pediococcus acidilactici was the dominant species in the control silage. LP3-27 inoculation also simplified the bacterial interaction networks of ensiled alfalfa. Beta-cyp degradation was positively correlated with L. pentosus in LP- inoculated silages, which confirmed the function of beta-cyp degradation by L. pentosus. In addition, higher beta-cyp degradation was observed in silage with 35% versus 43% DM. In summary, strain LP3-27 could be used as a candidate inoculum for bioremediation of beta-cyp-contaminated silage and to produce safe silage for animal production.

Effect of Bacillus amyloliquefaciens and Bacillus subtilis on fermentation, dynamics of bacterial community and their functional shifts of whole-plant corn silage

Background

Bacillus amyloliquefaciens (BA) and Bacillus subtilis (BS) are usually used as feed supplements directly or bacterial inoculants in biological feeds for animals. However, few research have reported the effects of BA and BS on fermentation characteristics and bacterial community successions of whole-plant corn silage during ensiling. If the BA and BS inoculants have positive effects on silages, then they could not only improve fermentation characteristics, but also deliver BA or BS viable cells to ruminants, which would play its probiotic effect. Therefore, the objectives of this study were to investigate the effects of BA and BS on the fermentation, chemical characteristics, bacterial community and their metabolic pathway of whole-plant corn silage.

Results

Freshly chopped whole-plant corn was inoculated without or with BA and BS, respectively, and ensiled for 1, 3, 7, 14 and 60 d. Results showed that BA and BS inoculations increased lactic acid concentrations of whole-plant corn silages compared with control, and BA inoculation decreased acetic acid concentrations, whereas BS inoculation decreased fiber contents and increased crude protein (CP) content. Higher water-soluble carbohydrate contents and lower starch contents were observed in BA- and BS-inoculated silages compared with that in control. The decreased CP content and increased non-protein nitrogen content were observed in BA-inoculated silage, which was consistent with the higher amino acid metabolism abundances observed in BA-inoculated silage. In addition, it was noteworthy that BA and BS inoculations increased the metabolism of cofactors and vitamins, and decreased the relative abundances of drug resistance: antimicrobial pathways. We also found that the bacterial metabolism pathways were clearly separated into three clusters based on the ensiling times of whole-plant corn silage in the present study. There were no significant differences in bacterial community compositions among the three groups during ensiling. However, BA and BS inoculations decreased the relative abundances of undesirable bacteria such as Acetobacter and Acinetobacter.

Conclusion

Our findings suggested that the BS strain was more suitable as silage inoculants than the BA strain in whole-plant corn silage in this study.

Comparison of the Clinical Outcomes of Full-Endoscopic Visualized Foraminoplasty and Discectomy Versus Microdiscectomy for Lumbar Disc Herniation

OBJECTIVE

This retrospective case-control study aimed to evaluate and compare the clinical outcomes of full-endoscopic visualized foraminoplasty and discectomy (FEVFD) with microdiscectomy (MD) for lumbar disc herniation (LDH).

METHODS

Data from 198 patients who presented with LDH between January 2016 and December 2017 treated by either FEVFD or MD were retrospectively analyzed. The inclusion criteria were single-level LDH, unilateral radiating leg pain with or without positive Lasegue's sign, and failure of standard conservative treatment for at least 12 weeks. The patients were categorized into an FEVFD group (n = 102) or an MD group (n = 96), according to the surgical procedure performed. Operative time, time in bed after surgery, postoperative hospitalization time, complications, and reoperations were recorded. Visual analog scales (VAS) for leg and back pain, Oswestry Disability index (ODI), 36-Item Short-Form Health Survey physical function (SF36-PF), and bodily pain (SF36-BP) scores were assessed and compared between the two groups.

RESULTS

The demographic data and baseline characteristics of the two groups were not significantly different. Operative time for the FEVFD group (73.82 ± 20.73 min) was longer than that for the MD group (64.74 ± 17.37 min) (P = 0.003), and fluoroscopy time for the FEVFD group (1.71 ± 0.58s) was longer than that for the MD group (1.30 ± 0.33s) (P < 0.001). However, time in bed experienced in the FEVFD group (8.51 ± 2.10 h) was less than that in the MD group (9.24 ± 2.01 h) (P = 0.014), and postoperative hospitalization time experienced in the FEVFD group (2.89 ± 0.83d) was also shorter than that in the MD group (4.94 ± 1.35d) (P < 0.001). All patients completed 24 months of follow-up. Postoperative scores at each follow-up for the VAS for leg and back pain, ODI, SF36-PF, and SF36-BP all improved significantly for both groups, as compared to the preoperative data (P < 0.05). The mean preoperative and postoperative scores for the VAS for leg and back pain, ODI, SF36-PF, and SF36-BP were not significantly different between the two groups. According to the modified MacNab criteria, the outcomes of the procedures were rated as excellent or good by 92.16% and 93.75% of the patients in the FEVFD and MD groups, respectively. One patient suffered a nerve root injury during the discectomy, one patient suffered from a dural tear, and two patients suffered from a residual herniation in the FEVFD group. One patient in the MD group suffered from poor wound healing. Moreover, recurrence happened in two cases in the FEVFD group, and in one case in the MD group.

CONCLUSION

FEVFD and MD are both reliable techniques for the treatment of symptomatic LDH. FEVFD resulted in a more rapid recovery and equivalent clinical outcomes after 24 months of follow-up.

Engineering Extracellular Vesicles Restore the Impaired Cellular Uptake and Attenuate Intervertebral Disc Degeneration

Extracellular vesicles (EVs) are potential alternatives for mesenchymal stem cells (MSCs) in the treatment of musculoskeletal degenerative diseases, including intervertebral disc degeneration (IDD). Usually, EVs are internalized and then deliver bioactive molecules that impart phenotypic changes in recipient cells. For effective utilization of EVs in the IDD therapy, understanding the mechanism of EV uptake is of vital importance. In this study, we found that EVs delivered antioxidant proteins to protect against pyroptosis of nucleus pulposus cells (NPCs). In particular, the therapeutic effect of EVs decreased in TNF-α-treated NPCs due to the impaired caveolae-mediated endocytosis pathway. Transcriptome sequencing and functional verification revealed that caveolae associated protein 2 (Cavin-2) played an important role in the uptake process of EVs. We then constructed the Cavin-2-modified engineering EVs via the gene-editing of parental MSCs. These kinds of modified EVs presented an improved uptake rate in TNF-α-treated NPCs, which effectively ameliorated the cell death of NPCs in a three-dimensional hydrogel culture model and retarded the progression of IDD in the ex vivo organ culture model. Collectively, these findings illustrate the mechanism of EV uptake in NPCs and explore the application of engineering EVs in the treatment of IDD.

Biomechanical Evaluation of Different Surgical Approaches for the Treatment of Adjacent Segment Diseases After Primary Anterior Cervical Discectomy and Fusion: A Finite Element Analysis

Symptomatic adjacent segment disease (ASD) is a common challenge after anterior cervical discectomy and fusion (ACDF). The objective of this study was to compare the biomechanical effects of a second ACDF and laminoplasty for the treatment of ASD after primary ACDF. We developed a finite element (FE) model of the C2-T1 based on computed tomography images. The FE models of revision surgeries of ACDF and laminoplasty were simulated to treat one-level and two-level ASD after primary ACDF. The range of motion (ROM) and intradiscal pressure (IDP) of the adjacent segments, and stress in the cord were analyzed to investigate the biomechanical effects of the second ACDF and laminoplasty. The results indicated that revision surgery of one-level ACDF increased the ROM and IDP at the C2–C3 segment, whereas two-level ACDF significantly increased the ROM and IDP at the C2–C3 and C7-T1 segments. Furthermore, no significant changes in the ROM and IDP of the laminoplasty models were observed. The stress in the cord of the re-laminoplasty model decreased to some extent, which was higher than that of the re-ACDF model. In conclusion, both ACDF and laminoplasty can relieve the high level of stress in the spinal cord caused by ASD after primary ACDF, whereas ACDF can achieve better decompression effect. Revision surgery of the superior ACDF or the superior and inferior ACDF after the primary ACDF increased the ROM and IDP at the adjacent segments, which may be the reason for the high incidence of recurrent ASD after second ACDF.

Effects of malic or citric acid on the fermentation quality, proteolysis and lipolysis of alfalfa silage ensiled at two dry matter contents

This study evaluated the effects of two organic acids on the fermentation of alfalfa silages at different dry matter (DM) contents. Alfalfa was wilted to DM contents of 30% (moderately low) and 38% (normal) and ensiled without additives (control) or treated with 0.6% fresh matter DL-malic acid (MA) or 0.6% fresh matter citric acid (CA) for 60 days. After ensiling, silages with a normal DM were higher in pH, water-soluble carbohydrates (WSC) and DM loss (p < 0.05) when compared to silages ensiled at a moderately low DM. The higher DM content also limited proteolysis in silages indicated by lower concentrations of ammonia N (NH₃ -N). Compared with the control group, MA and CA-treated silages had lower pH, lower concentrations of acetic acid and NH₃ -N but higher concentrations of lactic acid. The addition of MA and CA reduced DM losses in silages when compared to the control group except for MA-treated silage at a moderately low DM in which only numerically lower DM loss was observed. Malic acid and CA also resulted in a higher proportion of polyunsaturated fatty acids, especially in silages with a moderately low DM. Including MA and CA could promote silage fermentation, limit proteolysis and lipolysis at the lower and medium-to-high end of DM contents in alfalfa silages.

Influence of a cholesterol-lowering strain Lactobacillus plantarum LP3 isolated from traditional fermented yak milk on gut bacterial microbiota and metabolome of rats fed with a high-fat diet

L. plantarum LP3 isolated from traditinal fermented Tibetan yak milk has been identified as a potential probiotic candidate strain with high cholesterol-lowering activity. In this study, thirty Sprague-Dawley (SD) rats were randomly divided into three groups, including normal diet (NC), high-fat diet (HC), and high-fat diet + L. plantarum LP3 (HLp). The effects of L. plantarum LP3 on plasma lipid profile, gut bacterial microbiota, and metabolome induced by high-fat diet in rats were investigated. Results shown that L. plantarum LP3 administration was found to reduce the levels of total cholesterol, triglyceride, and low-density lipoprotein cholesterol (LDL-C) and atherogenic index in the serum of high-fat diet rats. It also controlled the decrease of Bacteroidetes and increase of Firmicutes at the phylum level in gut microbiota induced by high-fat diet in SD rats and increased the diversity and relative abundance of intestinal flora in obese rats. In particular, the LP3 strain controlled the changes induced by the high-fat diet in the abundance of for Lachnospiraceae and Erysipelotrichaceae. We also further observed the beneficial regulatory effects of L. plantarum LP3 on changes in the levels of obesity-related metabolites. The biosynthesis of fatty acids, steroids, and bile acids and metabolism of linoleic acid, linolenic acid, and arachidonic acid were the main metabolic pathways adjusted by L. plantarum LP3 in obese rats, and the metabolic rates were similar to those observed in normal diet rats levels. The findings of this study provided useful information on the mechanism underlying the hypocholesterolemic effects of L. plantarum LP3 in the high-fat induced SD rat model with the perspective of modulation of gut microbiota and metabolites.

Phenomenological Constraints on the Transport Properties of QCD Matter with Data-Driven Model Averaging

Using combined data from the Relativistic Heavy Ion and Large Hadron Colliders, we constrain the shear and bulk viscosities of quark-gluon plasma (QGP) at temperatures of ∼150-350  MeV. We use Bayesian inference to translate experimental and theoretical uncertainties into probabilistic constraints for the viscosities. With Bayesian model averaging we propagate an estimate of the model uncertainty generated by the transition from hydrodynamics to hadron transport in the plasma's final evolution stage, providing the most reliable phenomenological constraints to date on the QGP viscosities.

Metformin facilitates mesenchymal stem cell-derived extracellular nanovesicles release and optimizes therapeutic efficacy in intervertebral disc degeneration

Extracellular vesicles (EVs) are extracellular nanovesicles that deliver diverse cargoes to the cell and participate in cell communication. Mesenchymal stem cell (MSCs)-derived EVs are considered a therapeutic approach in musculoskeletal degenerative diseases, including intervertebral disc degeneration. However, limited production yield and unstable quality have impeded the clinical application of EVs. In the present study, it is indicated that metformin promotes EVs release and alters the protein profile of EVs. Metformin enhances EVs production via an autophagy-related pathway, concomitantly with the phosphorylation of synaptosome-associated protein 29. More than quantity, quality of MSCs-derived EVs is influenced by metformin treatment. Proteomics analysis reveals that metformin increases the protein content of EVs involved in cell growth. It is shown that EVs derived from metformin-treated MSCs ameliorate intervertebral disc cells senescence in vitro and in vivo. Collectively, these findings demonstrate the great promise of metformin in EVs-based intervertebral disc regeneration.

Different lactic acid bacteria and their combinations regulated the fermentation process of ensiled alfalfa: ensiling characteristics, dynamics of bacterial community and their functional shifts

The objectives of this study were to investigate the adaptation and competition of Lactobacillus plantarum, Pediococcus pentosaceus and Enterococcus faecalis inoculated in alfalfa silage alone or in combination on the fermentation quality, dynamics of bacterial community, and their functional shifts using single-molecule real-time (SMRT) sequencing technology. Before ensiling, alfalfa was inoculated with L. plantarum (Lp), P. pentosaceus (Pp), E. faecalis (Ef) or their combinations (LpPp, LpEf, LpPpEf) and sampled at 1, 3, 7, 14 and 60 days. After 60-days fermentation, the Lp-, Pp- and LpPp-inoculated silages had lower pH but greater concentrations of lactic acid were observed in Pp, LpEf and LpPpEf-inoculated silages. The inoculants altered the keystone taxa and the bacterial community dynamics in different manners, where L. plantarum, Weissella cibaria and L. pentosaceus dominated the bacterial communities after 14 days-fermentation in all treatments. The silages with better fermentation quality had simplified bacterial correlation structures. Moreover, different inoculants dramatically changed the carbohydrate, amino acid, energy, nucleotide and vitamin metabolism of bacterial communities during ensiling. Results of the current study indicate that effect of different inoculants on alfalfa silage fermentation was implemented by modulating the succession of bacterial community, their interactions and metabolic pathways as well during ensiling.

Comparison of Clinical Outcomes Following Lumbar Endoscopic Unilateral Laminotomy Bilateral Decompression and Minimally Invasive Transforaminal Lumbar Interbody Fusion for One-Level Lumbar Spinal Stenosis With Degenerative Spondylolisthesis

Introduction: Both lumbar endoscopic unilateral laminotomy bilateral decompression (LE-ULBD) and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) have been used to treat one-level lumbar spinal stenosis (LSS) with degenerative spondylolisthesis, while the differences of the clinical outcomes are still uncertain.

Methods: Among 60 consecutive patients included, 24 surgeries were performed by LE-ULBD and 36 surgeries were performed by MI-TLIF. Patient demographics, operation characteristics and complications were recorded. Sagittal parameters, including slip percentage (SP) and slip angle (SA) were compared. The visual analog scale (VAS) score, the Oswestry Disability Index (ODI) score, and Macnab criteria were used to evaluate the clinical outcomes. Follow-up examinations were conducted at 3, 6, 12, and 24 months postoperatively.

Results: The estimated blood loss, time to ambulation and length of hospitalization of the LE-ULBD group were shorter than the MI-TLIF group. Preoperative and final follow-up SP of the LE-ULBD group was of no significant difference, while final follow-up SP of the MI-TLIF group was significantly improved compared with preoperative SP. The postoperative mean VAS and ODI scores decreased significantly in both LE-ULBD group and MI-TLIF group. According to the modified Macnab criteria, the outcomes rated as excellent/good rate were 95.8 and 97.2%, respectively, in both LE-ULBD group and MI-TLIF group. Intraoperative complication rate of the LE-ULBD and the MI-TLIF group were 4.2 and 0%, respectively. One case of intraoperative epineurium injury was observed in the LE-ULBD group. Postoperative complication rate of the LE-ULBD and the MI-TLIF group were 0 and 5.6%, respectively. One case with transient urinary retention and one case with pleural effusion were observed in the MI-TLIF group.

Conclusion: Both LE-ULBD and MI-TLIF are safe and effective to treat one-level LSS with degenerative spondylolisthesis.

Mechanosensitive Ion Channel Piezo1 Activated by Matrix Stiffness Regulates Oxidative Stress-Induced Senescence and Apoptosis in Human Intervertebral Disc Degeneration

Mechanical stimulation plays a crucial part in the development of intervertebral disc degeneration (IDD). Extracellular matrix (ECM) stiffness, which is a crucial mechanical microenvironment of the nucleus pulposus (NP) tissue, contributes to the pathogenesis of IDD. The mechanosensitive ion channel Piezo1 mediates mechanical transduction. This study purposed to investigate the function of Piezo1 in human NP cells under ECM stiffness. The expression of Piezo1 and the ECM elasticity modulus increased in degenerative NP tissues. Stiff ECM activated the Piezo1 channel and increased intracellular Ca2+ levels. Moreover, the activation of Piezo1 increased intracellular reactive oxygen species (ROS) levels and the expression of GRP78 and CHOP, which contribute to oxidative stress and endoplasmic reticulum (ER) stress. Furthermore, stiff ECM aggravated oxidative stress-induced senescence and apoptosis in human NP cells. Piezo1 inhibition alleviated oxidative stress-induced senescence and apoptosis, caused by the increase in ECM stiffness. Finally, Piezo1 silencing ameliorated IDD in an in vivo rat model and decreased the elasticity modulus of rat NP tissues. In conclusion, we identified the mechanosensitive ion channel Piezo1 in human NP cells as a mechanical transduction mediator for stiff ECM stimulation. Our results provide novel insights into the mechanism of mechanical transduction in NP cells, with potential for treating IDD.

Ferroportin-Dependent Iron Homeostasis Protects against Oxidative Stress-Induced Nucleus Pulposus Cell Ferroptosis and Ameliorates Intervertebral Disc Degeneration In Vivo

Ferroptosis is a specialized form of regulated cell death that is charactered by iron-dependent lethal lipid peroxidation, a process associated with multiple diseases. However, its role in the pathogenesis of intervertebral disc degeneration (IVDD) is rarely investigated. This study is aimed at investigating the role of ferroptosis in oxidative stress- (OS-) induced nucleus pulposus cell (NPC) decline and the pathogenesis of IVDD and determine the underlying regulatory mechanisms. We used tert-butyl hydroperoxide (TBHP) to simulate OS conditions around human NPCs. Flow cytometry and transmission electron microscopy were used to identify ferroptosis, while iron assay kit, Perl's staining, and western blotting were performed to assay the intracellular iron levels. A ferroportin- (FPN-) lentivirus and FPN-siRNA were constructed and used to explore the relationship between FPN, intracellular iron homeostasis, and ferroptosis. Furthermore, hinokitiol, a bioactive compound known to specifically resist OS and restore FPN function, was evaluated for its therapeutic role in IVDD both in vitro and in vivo. The results indicated that intercellular iron overload plays an essential role in TBHP-induced ferroptosis of human NPCs. Mechanistically, FPN dysregulation is responsible for intercellular iron overload under OS. The increase in nuclear translocation of metal-regulatory transcription factor 1 (MTF1) restored the function of FPN, abolished the intercellular iron overload, and protected cells against ferroptosis. Additionally, hinokitiol enhanced the nuclear translocation of MTF1 by suppressing the JNK pathway and ameliorated the progression of IVDD in vivo. Taken together, our results demonstrate that ferroptosis and FPN dysfunction are involved in the NPC depletion and the pathogenesis of IVDD under OS. To the best of our knowledge, this is the first study to demonstrate the protective role of FPN in ferroptosis of NPCs, suggesting its potential used as a novel therapeutic target against IVDD.

Nanotechnology for catalysis and solar energy conversion

This roadmap on Nanotechnology for Catalysis and Solar Energy Conversion focuses on the application of nanotechnology in addressing the current challenges of energy conversion: 'high efficiency, stability, safety, and the potential for low-cost/scalable manufacturing' to quote from the contributed article by Nathan Lewis. This roadmap focuses on solar-to-fuel conversion, solar water splitting, solar photovoltaics and bio-catalysis. It includes dye-sensitized solar cells (DSSCs), perovskite solar cells, and organic photovoltaics. Smart engineering of colloidal quantum materials and nanostructured electrodes will improve solar-to-fuel conversion efficiency, as described in the articles by Waiskopf and Banin and Meyer. Semiconductor nanoparticles will also improve solar energy conversion efficiency, as discussed by Boschloo et al in their article on DSSCs. Perovskite solar cells have advanced rapidly in recent years, including new ideas on 2D and 3D hybrid halide perovskites, as described by Spanopoulos et al 'Next generation' solar cells using multiple exciton generation (MEG) from hot carriers, described in the article by Nozik and Beard, could lead to remarkable improvement in photovoltaic efficiency by using quantization effects in semiconductor nanostructures (quantum dots, wires or wells). These challenges will not be met without simultaneous improvement in nanoscale characterization methods. Terahertz spectroscopy, discussed in the article by Milot et al is one example of a method that is overcoming the difficulties associated with nanoscale materials characterization by avoiding electrical contacts to nanoparticles, allowing characterization during device operation, and enabling characterization of a single nanoparticle. Besides experimental advances, computational science is also meeting the challenges of nanomaterials synthesis. The article by Kohlstedt and Schatz discusses the computational frameworks being used to predict structure-property relationships in materials and devices, including machine learning methods, with an emphasis on organic photovoltaics. The contribution by Megarity and Armstrong presents the 'electrochemical leaf' for improvements in electrochemistry and beyond. In addition, biohybrid approaches can take advantage of efficient and specific enzyme catalysts. These articles present the nanoscience and technology at the forefront of renewable energy development that will have significant benefits to society.

The distinct roles of myosin IIA and IIB under compression stress in nucleus pulposus cells

Objectives

Inappropriate or excessive compression applied to intervertebral disc (IVD) contributes substantially to IVD degeneration. The actomyosin system plays a leading role in responding to mechanical stimuli. In the present study, we investigated the roles of myosin II isoforms in the compression stress‐induced senescence of nucleus pulposus (NP) cells.

Material and methods

Nucleus pulposus cells were exposed to 1.0 MPa compression for 0, 12, 24 or 36 hours. Immunofluorescence and co‐immunoprecipitation analysis were used to measure the interaction of myosin IIA and IIB with actin. Western blot analysis and immunofluorescence staining were used to detect nuclear expression and nuclear localization of MRTF‐A. In addition, the expression levels of p‐RhoA/RhoA, ROCK1/2 and p‐MLC/MLC were measured in human NP cells under compression stress and in degenerative IVD tissues.

Results

Compression stress increased the interaction of myosin IIA and actin, while the interaction of myosin IIB and actin was reduced. The actomyosin cytoskeleton remodelling was involved in the compression stress‐induced fibrotic phenotype mediated by MRTF‐A nuclear translocation and inhibition of proliferation in NP cells. Furthermore, RhoA/ROCK1 pathway activation mediated compression stress‐induced human NP cells senescence by regulating the interaction of myosin IIA and IIB with actin.

Conclusions

We for the first time investigated the regulation of actomyosin cytoskeleton in human NP cells under compression stress. It provided new insights into the development of therapy for effectively inhibiting IVD degeneration.

Comparison of lumbar endoscopic unilateral laminotomy bilateral decompression and minimally invasive surgery transforaminal lumbar interbody fusion for one-level lumbar spinal stenosis

BACKGROUND

The aim of the present study is to compare the clinical outcomes and postoperative complications of lumbar endoscopic unilateral laminotomy bilateral decompression (LE-ULBD) and minimally invasive surgery transforaminal lumbar interbody fusion (MIS-TLIF) to treat one-level lumbar spinal stenosis (LSS) without degenerative spondylolisthesis or deformity.

METHODS

A retrospective analysis of 112 consecutive patients of one-level LSS undergoing either LE-ULBD or MIS-TLIF was performed. Patient demographics, operation time, estimated blood loss, time to ambulation, length of hospitalization, intraoperative and postoperative complications were recorded. The visual analog scale (VAS) score for leg and back pain, the Oswestry Disability Index (ODI) score, and the Macnab criteria were used to evaluate the clinical outcomes. The healthcare cost was also recorded.

RESULTS

The operation time, estimated blood loss, time to ambulation and length of hospitalization of LE-ULBD group were shorter than MIS-TLIF group. The postoperative mean VAS and ODI scores decreased significantly in both groups. According to the modified Macnab criteria, the outcomes rated as excellent/good rate were 90.6 and 93.8% in the two groups. The mean VAS scores, ODI scores and outcomes of the modified Macnab criteria of both groups were of no significant difference. The healthcare cost of LE-ULBD group was lower than MIS-TLIF group. Two cases of intraoperative epineurium injury were observed in the LE-ULBD group. One case of cauda equina injury was observed in the LE-ULBD group. No nerve injury, dural injury or cauda equina syndrome was observed in MIS-TLIF group. However, one case with transient urinary retention, one case with pleural effusion, one case with incision infection and one case with implant dislodgement were observed in MIS-TLIF group.

CONCLUSIONS

Both LE-ULBD and MIS-TLIF are safe and effective to treat one-level LSS without degenerative spondylolisthesis or deformity. LE-ULBD is a more minimally invasive option and of less economic burden compared with MIS-TLIF. Decompression plus instrumented fusion may be not necessary for one-level LSS without degenerative spondylolisthesis or deformity.

Characterization of the microbial community, metabolome and biotransformation of phenolic compounds of sainfoin (Onobrychis viciifolia) silage ensiled with or without inoculation of Lactobacillus plantarum

The present study investigated the bacterial community, metabolome and biotransformation of phenolic compounds in sainfoin silage inoculated either with or without Lactobacillus plantarum. Our results revealed that the epiphytic microbiota of wilted sainfoin mainly comprised Acinetobacter, Spingomonas, Pseudomonas, Lactobacillus, Delftia and Aquabacterium. After ensiling, L. acetotolerans, L. buchneri, L. plantarum, L. pentosus and Clostridium tyrobutricum were the dominant species. Compared to the control, the inoculant L. plantarum increased the relative abundance of L. buchneri while decreased that of the other dominant species. The ensiling process increased the concentrations of 21 flavones, 16 flavonols, 16 flavonoids, 14 flavanones and 9 isoflavones while decreased other 32 flavones and 11 anthocyanins, which mainly modulated by the "isoflavonoid biosynthesis" and "flavonoid biosynthesis" pathways. The inoculant L. plantarum mainly reduced the concentrations of 10 flavones. Compared with the control, the inoculant L. plantarum mainly affected the metabolism pathways related to carbohydrates and nitrogen.

Clinically suspected fibrocartilaginous embolism: a case report and literature review

Spinal cord infarction (SCI) occurs rarely and is characterized by abrupt onset of neck or back pain and neurologic deterioration. Fibrocartilaginous embolism (FCE) of the spinal cord is a rare but possible cause of acutely progressive spinal cord symptoms. Here, we report the case of an older woman who developed acute paraplegia with SCI on the 10th day after thoracic spine surgery. Although definitive FCE diagnosis can be confirmed only histologically, the characteristic clinical and radiological features were highly suggestive of FCE. Furthermore, 40 clinically suspected cases of FCE are reviewed.

Evaluation of the effect of feruloyl esterase-producing Lactobacillus plantarum and cellulase pretreatments on lignocellulosic degradation and cellulose conversion of co-ensiled corn stalk and potato pulp

The effects of feruloyl esterase-producing Lactobacillus plantarum A1, cellulase, or their combination on the fermentation characteristics, carbohydrate composition, and enzymatic hydrolysis of mixed corn stalk and potato pulp silage were investigated. Two mixture ratios were used: a weight ratio of rehydrated corn stalk to potato pulp of 35:1 (HD) and a weight ratio of dry corn stalk to potato pulp of 5:11 (LD). No advantage was observed with the addition of strain A1 alone for lignocellulosic degradation and cellulose conversion, while its combination with cellulase enhanced the lignocellulosic degradation and preserved more fermentable carbohydrates in co-ensiled corn stalk and potato pulp. The enzymatic hydrolysis results indicated a potential benefit of pretreatment for biogas production, as the co-ensiled HD ratio mixture without additive treatment showed high glucose yield after enzymatic hydrolysis following 60 d of fermentation.

Biomechanical Evaluation and the Assisted 3D Printed Model in the Patient-Specific Preoperative Planning for Thoracic Spinal Tuberculosis: A Finite Element Analysis

Posterior fixation is superior to anterior fixation in the correction of kyphosis and maintenance of spinal stability for the treatment of thoracic spinal tuberculosis. However, the process of selecting the appropriate spinal fixation method remains controversial, and preoperative biomechanical evaluation has not yet been investigated. In this study, we aimed to analyze the application of the assisted finite element analysis (FEA) and the three-dimensional (3D) printed model for the patient-specific preoperative planning of thoracic spinal tuberculosis. An adult patient with thoracic spinal tuberculosis was included. A finite element model of the T7−T11 thoracic spine segments was reconstructed to analyze the biomechanical effect of four different operative constructs. The von Mises stress values of the implants in the vertical axial load and flexion and extension conditions under a 400-N vertical axial pre-load and a 10-N⋅m moment were calculated and compared. A 3D printed model was used to describe and elucidate the patient’s condition and simulate the optimal surgical design. According to the biomechanical evaluation, the patient-specific preoperative surgical design was prepared for implementation. The anterior column, which was reconstructed with titanium alloy mesh and a bone graft with posterior fixation using seven pedicle screws (M+P) and performed at the T7–T11 level, decreased the von Mises stress placed on the right rod, T7 pedicle screw, and T11 pedicle. Moreover, the M+P evaded the left T9 screw without load bearing. The 3D printed model and preoperative surgical simulation enhanced the understanding of the patient’s condition and facilitated patient-specific preoperative planning. Good clinical results, including no complication of implants, negligible loss of the Cobb angle, and good bone fusion, were achieved using the M+P surgical design. In conclusion, M+P was recommended as the optimal method for preoperative planning since it enabled the preservation of the normal vertebra and prevented unnecessary internal fixation. Our study indicated that FEA and the assisted 3D printed model are tools that could be extremely useful and effective in the patient-specific preoperative planning for thoracic spinal tuberculosis, which can facilitate preoperative surgical simulation and biomechanical evaluation, as well as improve the understanding of the patient’s condition.

Biomechanical evaluation of anterior and posterior lumbar surgical approaches on the adjacent segment: a finite element analysis

The purpose of this study was to use models of spine to compare range of motion and intradiscal pressure of adjacent segments performing anterior and/or posterior lumbar surgical approaches and predict potential risk of adjacent segment degeneration. A previously validated finite element model of the intact L1-S1 segments was used. Three different anterior and one posterior surgical fixation approaches for tuberculosis were performed in L3-L5. Three different anterior surgical models were constructed according to the anterior approaches involving debridement, bone graft with or without titanium mesh, and internal fixation with different number of screws and rods. The posterior surgical approach involved transforaminal lumbar interbody debridement, bone graft, and internal fixation. Range of motion and intradiscal pressure of segments adjacent to the fusion were assessed, and biomechanical influences were compared. Intradiscal pressure and range of motion of the adjacent L2/3 and L5/S1 increased during different physiological movements after anterior and/or posterior surgical approaches as compared to baseline values. Comparison between the biomechanical values assessed after different anterior surgical approaches yielded no significant difference. After anterior and posterior surgical approaches were performed on the same model, there were no significant differences in intradiscal pressure and range of motion of the adjacent L2/3 and L5/S1. Anterior and/or posterior lumbar surgical approaches increased range of motion and intradiscal pressure in L2/3 and L5/S1, suggesting each lumbar surgical approach assessed has the potential risk of adjacent segment degeneration. However, there were no significant differences between the biomechanical measurements across the different surgical approaches evaluated.

The bacterial community and metabolome dynamics and their interactions modulate fermentation process of whole crop corn silage prepared with or without inoculants

Multi‐omics approach was adopted to investigate the modulation of bacterial microbiota and metabolome as well as their interactions in whole crop corn ensiling systems by inoculating homofermentative Lactobacillus plantarum or heterofermentative Lactobacillus buchneri. Inoculations of the two different inoculants resulted in substantial differences in microbial community and metabolic composition as well as their dynamics in ensiled corn. Inoculants also altered the correlations of microbiota in different manners, and various keystone species were identified in corn silages with different treatments. Many metabolites with biofunctional activities like bacteriostatic, antioxidant, central nervous system inhibitory and anti‐inflammatory were found in the present silage. A constitutive difference in microbiota dynamics was found for several pathways, which were upregulated by specific taxa in middle stage of fermentation, and widespread associations between metabolites with biofunctions and the species of lactic acid bacteria dominated in silage were observed. Multiple microbial and metabolic structures and dynamics were correlated and affected the fermentation process of the corn ensiling systems. Results of the current study improve our understanding of the complicated biological process underlying silage fermentation and provide a framework to re‐evaluate silages with biofunctions, which may contribute to target‐based regulation methods to produce functional silage for animal production.

Minimally Invasive Surgery Oblique Lumbar Interbody Debridement and Fusion for the Treatment of Lumbar Spondylodiscitis

Objective

To evaluate the efficacy and feasibility of minimally invasive oblique lumbar interbody debridement and fusion for the treatment of conservatively ineffective lumbar spondylodiscitis.

Methods

This is a retrospective study. Between December 2016 and November 2017, a total of 14 consecutive patients (eight males and six females, with an average age of 49.1 years, range from 42 to 74 years) with single‐level lumbar spondylodiscitis were included in the study. The inclusion criteria include single‐level spondylodiscitis without spinal deformity or epidural abscess, ineffective conservative treatment (continuously aggravated clinical symptoms and uncontrollable infective symptoms treated with antibiotics for more than 6 weeks), minimally invasive oblique lumbar interbody fusion surgery (Mis‐OLIF) and iliac graft for the treatment of lumbar spondylodiscitis, and postoperative follow‐up >12 months. Each patient was treated Mis‐OLIF. Clinical outcomes including demographic characteristics, erythrocyte sedimentation rate (ESR), C‐reactive protein (CRP), visual analog scale (VAS), the Oswestry Disability Index (ODI), American Spinal Injury Association neurological classification, and lordotic angle were analyzed.

Results

The infectious levels included L1/2 (one patient), L2/3 (two patients), L3/4 (eight patients), and L4/5 (three patients). The pathogens found in these patients included Staphylococcus aureus (5), brucellosis (6), and enterobacterium (2). The pathogen was undefined in one patient. The mean duration of the surgery, mean blood loss, and mean follow‐up were 89.3 ± 17.5 min, 155.0 ± 49.4 mL, and 16.8 ± 4.2 months, respectively. The ESR and CRP decreased after Mis‐OLIF and antibiotic administration. The average preoperative VAS score was 6.9 ± 0.9, then decreased to 3.0 ± 1.0 (t = 14.18, P < 0.001) and 0.6 ± 0.7 (t = 20.68, P < 0.001) before discharge and at final follow‐up, respectively. The average preoperative ODI score was 58.4 ± 13.0, then decreased to 28.3 ± 6.1 (t = 18.6, P < 0.001) and 8.0 ± 4.6 (t = 22.7, P < 0.001) before discharge and at final follow‐up, respectively. None of the patients developed postoperative ileus, vascular injury, nerve injury, and ureteral injury. One patient suffered incision‐related complication that healed by debridement and dressing change. One patient developed subsidence of autologous iliac bone before discharge and achieved complete bony fusion after staying in bed and fixing it with a brace at 3 months follow‐up. All patients achieved bony fusion at final follow‐up.

Conclusion

Mis‐OLIF without anterior or posterior instrumentation and iliac graft is an effective and viable approach for the treatment of conservatively ineffective lumbar spondylodiscitis without spinal deformity or epidural abscess.

The efficacy of allograft bone using titanium mesh in the posterior-only surgical treatment of thoracic and thoracolumbar spinal tuberculosis

Background

The bony fusion of allograft bone using titanium mesh in the posterior-only surgical treatment of thoracic and thoracolumbar spinal tuberculosis has not been explained in detail. We aimed to analyze the efficacy of bony fusion of allograft bone using titanium mesh in the posterior-only surgical treatment of thoracic and thoracolumbar spinal tuberculosis.

Methods

We treated 32 thoracic or thoracolumbar tuberculosis patients by one-stage posterior debridement, allograft bone graft using titanium mesh, posterior instrumentation, and fusion from May 2011 to September 2015. The American Spinal Injury Association neurological classification, visual analog scale, and Oswestry disability index scores were analyzed preoperatively, postoperatively, and at final follow-up. The Cobb angles were recorded to evaluate the kyphosis correction and the loss of correction. The bony fusion was evaluated by X-ray and computed tomography images, and the bony fusion classifications were recorded.

Results

All patients had pain relief. The erythrocyte sedimentation rate, C-response protein, and hepatorenal function were normal at final follow-up. The American Spinal Injury Association neurological classification, visual analog scale, and Oswestry disability index scores were improved in all the patients. All patients achieved bone fusion. Twenty-eight patients achieved complete fusion (Grade I), whereas only four patients achieved partial fusion (Grade II). The preoperative Cobb angle was 33.6 ± 9.3°. The Cobb angle was reduced to 10.6 ± 2.6° postoperatively and was found to be 11.4 ± 3.1° at the final follow-up. The mean angle correction was 23.0 ± 8.9°, and the correction rate was 66.2 ± 12.2%. The mean angle lost was 0.8 ± 0.9°, and the lost rate was 5.8 ± 5.4% at the final follow-up.

Conclusions

Allograft bone using titanium mesh in the posterior-only surgical treatment is effective for patients with thoracic and thoracolumbar spinal tuberculosis. It can correct kyphosis, and most patients can achieve complete bony fusion.

Biomechanical evaluation of adjacent segment degeneration after one- or two-level anterior cervical discectomy and fusion versus cervical disc arthroplasty: A finite element analysis

BACKGROUND AND OBJECTIVE

To compare the biomechanical changes of adjacent segment degeneration (ASD) after one- or two-level anterior cervical discectomy and fusion (ACDF) versus cervical disc arthroplasty (CDA).

METHODS

A three-dimensional finite element (FE) model of intact C2-C7 segments was constructed and validated. In the one-level surgery model, the cage with plate implant or Prestige LP cervical disc prosthesis were integrated at C5-C6 segment into the FE model; while in the two-level surgery model, the prostheses were integrated at both C4-C5 and C5-C6 segments into the FE model. A pure moment of 1.0 Nm combined with a follower load of 73.6 N were imposed on C2 to investigate the flexion-extension, lateral bending, and axial rotation of different segments in the FE model. The segmental range of motion (ROM) and intradiscal pressure of the surgery models were investigated and compared with the intact model.

RESULTS

In the one-level model of ACDF, the ROM at C5-C6 was decreased, the ROM and intradiscal pressure at C4-C5 and C6-C7 segments were increased. In the two-level model of ACDF, the ROM at C4-C5 and C5-C6 were decreased, the ROM and intradiscal pressure at C3-C4 and C6-C7 were increased. However, in both one- and two-level models of CDA, the ROM of surgery segments were preserved, avoiding the increase of the ROM and intradiscal pressure at the adjacent segments.

CONCLUSIONS

Abnormal ROM and intradiscal pressure at the adjacent segments may contribute to the higher risk of ASD after ACDF compared with CDA.