Frontiers in Bioengineering and Biotechnology最新文献

Objectives: Intervertebral disc degeneration (IVDD) is a major contributor to chronic low back pain and disability worldwide, yet current treatments remain largely palliative and do not restore disc structure or biomechanical integrity. Stem cell-derived extracellular vesicles (SC-sEVs) have emerged as promising cell-free biologics capable of modulating inflammation, apoptosis, and extracellular matrix homeostasis.

Methods: This systematic review and meta-analysis evaluated the therapeutic efficacy of SC-sEVs in rat models of puncture-induced IVDD, with a specific focus on comparing hydrogel-assisted versus direct (non-hydrogel) delivery strategies. The review was prospectively registered in PROSPERO (CRD420250654980) and conducted according to PRISMA 2020 guidelines.

Results: Comprehensive searches of PubMed, Embase, and the Cochrane Library through August 2025 identified 19 studies enrolling 305 rats. Extracted outcomes included disc height index (DHI), MRI Pfirrmann grade, and histological score. Meta-analysis demonstrated significant improvements in DHI (mean difference [MD] = 12.8%, 95% CI 7.6-18.0), histological grade (MD = -4.1, 95% CI -5.1 to -3.2), and MRI Pfirrmann grade (MD = -1.5, 95% CI -1.8 to -1.2) at 4-8 weeks following treatment. Hydrogel-assisted delivery produced comparable overall efficacy to direct injection but contributed to reduced interstudy heterogeneity. Both human- and rat-derived EVs significantly improved all evaluated outcomes, with human-source EVs showing a modest advantage in MRI grading (P = 0.017). Risk-of-bias assessment indicated generally acceptable methodological quality, and no substantial publication bias was observed.

Conclusion: Overall, SC-sEV therapy demonstrates consistent regenerative benefits in preclinical IVDD models, supporting its translational promise as a minimally immunogenic, cell-free therapeutic for degenerative spine disorders. Future studies employing standardized protocols, mechanistic analyses, and long-term evaluation are needed to facilitate clinical translation.

Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD420250654980, identifier CRD420250654980.

Objectives: Reverse Potts shunt is a promising yet high-risk therapy for pediatric pulmonary arterial hypertension. Postoperative hemodynamics is critically influenced by shunt configuration but is difficult to predict. This study aimed to quantify the effects of shunt size and location on hemodynamics to guide surgical planning.

Methods: Based on a patient-specific model, four postoperative models with two different shunt locations [left pulmonary artery (LPA)-descending aorta (DAO) and pulmonary artery bifurcation-aortic arch] and three conduit sizes (4, 5, and 6 mm) were created. The direct Potts shunt model was created by a direct side-to-side anastomosis between the LPA and DAO with a 6-mm circular opening. Quantitative parameters including the shunt ratio (SR), which was defined as the percentage of the shunt flow rates to the total pulmonary inflow rate, lower limb oxygen saturation, and pressure were analyzed.

Results: Increasing the shunt size from 4 mm to 6 mm elevated the SR from 6.01% to 9.80%, concurrently reducing lower limb oxygen saturation from 89.57% to 86.52%. When taking 11,000 Pa as the threshold, this increased SR resulted in a reduction of the high-pressure area from 17.32% of the total pulmonary artery area to almost zero. Meanwhile, the high-pressure area on the aorta expanded from 8.72% of the total aortic area to 14.94%. These results indicated a reduction in the right ventricular afterload and an increase in the left ventricular afterload. Notably, a 6-mm shunt at the pulmonary artery bifurcation yielded a significantly larger SR than at the LPA (9.80% vs. 2.68%), which is attributed to a higher pressure gradient at the pulmonary artery bifurcation (1,201 Pa vs. 162 Pa).

Conclusion: The shunt location had a greater impact on the SR than shunt size within the 4 mm-6 mm range in this specific case. A 6-mm shunt at the pulmonary artery bifurcation yielded a significantly larger SR than at the LPA, which is attributed to the higher preoperative pressure gradient at the bifurcation site. Left heart function is as critical as right heart function in maintaining pressure balance and determining outcomes, as the shunt flow increases the left ventricular afterload.

Background: Revision surgery for femoral nonunion is technically challenging, and there is limited evidence supporting effective treatments for cases with multiple failed revisions. This study aims to evaluate the efficacy of platelet-rich plasma-enhanced "plum blossom" bone grafting combined with a bioactive chamber in treating refractory femoral nonunion after multiple failed revisions.

Methods: A retrospective analysis was conducted on patients with refractory femoral nonunion treated at a high-level trauma center between January 2021 and July 2024. These patients underwent mechanical optimization, platelet-rich plasma -enhanced "plum blossom" autologous iliac bone grafting, and bioactive chamber therapy. Radiographic outcomes included union rate and limb shortening, while clinical outcomes encompassed healing time, visual analog scale pain score, SF-36 quality of life score, Harris hip score, and complications.

Results: Thirty-three patients were included (24 males, 9 females), with a mean age of 42.64 ± 13.03 years. The average number of previous surgeries was 2.64 ± 1.17. The nonunion types were hypertrophic (4 cases, 12.10%), atrophic (24 cases, 72.70%), and oligotrophic (5 cases, 15.20%). The mean bone defect was 3.87 ± 1.05 cm, and the mean follow-up duration was 16.06 ± 3.37 months. The union rate was 96.97% (32/33), with a mean healing time of 9.78 ± 1.75 months. Post-treatment, significant improvements were observed in VAS score (4.27 ± 1.18 vs. 1.21 ± 1.05, p < 0.001), Harris hip score (50.91 ± 8.47 vs. 86.39 ± 7.75, p < 0.001), SF-36 score (59.21 ± 5.63 vs. 84.48 ± 5.32, p < 0.001), and limb shortening (2.20 ± 0.64 vs. 0.32 ± 0.57, p < 0.001). Two patients (6.06%) experienced severe complications (1 case of persistent nonunion, 1 case of deep vein thrombosis).

Conclusion: The synergistic effect of biomechanical stability and biological stimulation is a critical pathway to overcoming traditional treatment limitations. This study provides a reference method for managing refractory and recalcitrant femoral nonunion.

Objective: To employ shear wave elastography (SWE) to assess changes in stiffness and reliability in the vastus rectus muscle of healthy adults across different posture-contraction states. We analyzed the main effects and interactions of posture and contraction intensity on shear wave velocity (SWV) and explored its relationship with relevant biological parameters.

Methods: We recruited healthy participants, with two observers using SWE technology to measure the SWV of the vastus rectus muscle in the supine (relaxation, plantarflexion, and dorsiflexion) and sitting (relaxation, leg elevated, and 5-kg loading) positions. Intra- and interobserver reliabilities were evaluated using the intraclass correlation reliability. Repeated-measures analysis of variance was used to examine the main effects and interactions of posture and contraction state on SWV. Additionally, correlations between the SWV and rectus femoris thickness (RF_thick), circumference (RF_circ), cross-sectional area (RF_csa), and contraction index (RF_ci) were calculated.

Results: Forty-six adults (11 males and 35 females) completed the study. SWE measurements demonstrated high intra- and interobserver reliability across all conditions (ICC >0.80). Two-way repeated-measures analysis of variance revealed significant main effects of body position (F (1,45) = 58.85, P < 0.001, η_p ² = 0.567) and contraction state (F (1.76, 78.97) = 104.23, P < 0.001, η_p ² = 0.777), with a significant interaction (F (2,44) = 24.66, P < 0.001, η_p ² = 0.459). The SWV changes were more pronounced in the 5-kg load position (45.9%). Ultrasound parameters (RF_thick, RF_circ, RF_ci) varied significantly across conditions (P < 0.05), whereas the RF_csa did not (P = 0.194). The SWV was positively correlated with specific architectural parameters, depending on posture, but not with demographic variables (P > 0.05).

Conclusion: This study establishes a methodological basis for assessing the stiffness of the RF, identifying posture and contraction as key factors. Our findings underscore the need for standardized measurement and support the future application of SWE in biomechanics, sports, and rehabilitation.

Objective: This study aimed to compare the biomechanical stability of different-sized posterolateral tibial plateau fracture fragments under various internal fixation methods using three-dimensional finite element analysis (FEA) and to evaluate the influence of fragment size on displacement and stress distribution with L-shaped and posterior T-shaped plate fixation.

Methods: Three-dimensional FEA models of posterolateral tibial plateau fractures were constructed based on computed tomography (CT) data of an adult tibia. Large and small fracture fragments were simulated, with fixation using an L-shaped plate (large fragment: dual-screw transverse arm fixation; small fragment: single-screw transverse arm fixation) or a posterior T-shaped tibial plate (large fragment: four-screw fixation; small fragment: three-screw fixation). Axial loads of 250 N, 500 N, and 750 N were applied to each model. Maximum displacement and maximum von Mises stress of the fixation constructs were recorded and compared under a 750 N load.

Results: Under a 750 N axial load, FEA revealed: (1) L-shaped plate fixation group: the large-fragment model (dual-screw transverse arm) exhibited a maximum fixation displacement of 0.32 mm and a maximum von Mises stress of 349 MPa, whereas the small-fragment model (single-screw transverse arm) showed a maximum displacement of 0.37 mm and a maximum stress of 454 MPa. (2) Posterior T-shaped plate fixation group: the large-fragment model (four screws) demonstrated a maximum displacement of 0.29 mm and a maximum stress of 189 MPa, while the small-fragment model (three screws) had a maximum displacement of 0.32 mm and a maximum stress of 176 MPa. Overall displacement differences across groups were minimal, and the stress values of all fixation constructs remained below their yield strength, indicating no risk of failure.

Conclusion: Finite element analysis indicates that fragment size significantly affects the biomechanical stability of internal fixation for posterolateral tibial plateau fractures. For smaller fragments, L-shaped plate fixation with a single-screw transverse arm results in significantly elevated fixation stress. In contrast, posterior T-shaped plate fixation maintains favorable stability and lower stress, even with fewer proximal screws. Thus, for smaller posterolateral tibial plateau fracture fragments, posterior T-shaped plate fixation may represent a biomechanically superior option.

The valorization of tobacco stems, a major agricultural by-product with high lignin content, is hindered by the recalcitrance of plant cell walls. Conventional approaches using single microbes or enzymes suffer from inefficiency, instability, and poor performance on lignin-rich substrates. To address this, we proposed a "microbe-enzyme synergistic" strategy by combining Bacillus megaterium (a multifunctional degrader) with its own extracellular enzymes. Three treatments were designed: microbe-only (T_b), enzyme-only (T_e), and microbe-enzyme combination (T_b&e), with sterile water as the control (CK). Cell wall component contents, enzyme activities, and microbial community structure were analyzed after 7 days of fermentation. The T_b&e treatment achieved the most substantial degradation: 64.93% for cellulose, 57.89% for lignin, and 37.20% for pectin, significantly outperforming T_b and T_e. It also exhibited the highest activities of cellulase, laccase, and pectinase. High-throughput sequencing revealed that T_b&e specifically enriched Bacillus megaterium (94.97% of the community) while suppressing non-functional competitors. Our findings demonstrate that the synergy creates a positive feedback loop: initial enzymatic hydrolysis facilitates microbial colonization, which in turn boosts sustained enzyme production. This study elucidates a mechanistic model for efficient biodegradation and provides an innovative strategy for the high-value utilization of high-lignin agricultural wastes.

Objective: Lumbar disc herniation (LDH) has demonstrated a rising prevalence in contemporary clinical practice, significantly compromising patients' daily lives and potentially necessitating surgical intervention. While annulus fibrosus suture (AFS) techniques are increasingly incorporated into surgical protocols, current evidence remains inconclusive regarding their definitive clinical advantages.

Methods: We performed a comprehensive search of eight databases from inception to September 2025 to identify published articles on AFS for LDH. Outcome measures encompassed operative time, incision length, blood loss, length of stay (LOS), visual analog scale (VAS) score, Japanese Orthopedic Association (JOA) score, Oswestry disability index (ODI) score, disc height, recurrence, and complication. The quality of the studies was analyzed using the RoB-2 and ROBINS-I tools. Statistical analyses were performed using RevMan 5.4 software and Stata 17 software. The GRADE approach was used to evaluate the certainty of evidence for outcomes.

Results: A total of 58 studies encompassing 5,765 patients diagnosed with LDH. The control group had shorter operative time (MD = 4.85, 95% CI: 2.79 to 6.92, P < 0.00001) compared to the AFS group. There were no differences in terms of incision length, blood loss, LOS, JOA score, ODI score, and complication between the techniques. AFS group demonstrated a significant benefit over control group in terms of VAS score (MD = -0.24, 95% CI: -0.33 to -0.14, P < 0.00001), disc height (SMD = 1.36, 95% CI: 0.73 to 2.00, P < 0.0001), and recurrence (RR = 0.34, 95% CI: 0.27 to 0.42, P < 0.00001). The results of subgroup analysis showed that different study types and different follow-up times were a source of heterogeneity. The quality of evidence for outcome measures ranges from very low to moderate.

Conclusion: Current evidence suggests that AFS therapy may be advantageous in improving clinical symptoms and may reduce postoperative recurrence. Due to limited data and low quality of evidence, additional large-scale, multicenter trials are needed to verify and strengthen these findings.

Sequence verification of plasmids is a fundamental process in synthetic biology. For plasmid sequence verification using next-generation sequencing (NGS) library preparation, Tn5 transposase is widely used. Streamlined sequencing workflow for laboratory-scale applications is important; however, recombinant Tn5 production in-house can be laborious. In this study, we demonstrated that the addition of a large soluble tag was not essential for purification and that the fusion of a His10 tag and protein A was sufficient to yield active Tn5 transposase in adequate amounts. In addition, we evaluated exonuclease-based genomic DNA digestion for plasmid sequencing from an E. coli lysate and the data analysis pipeline of sequences derived from the Illumina iSeq100 platform for de novo assembly, reference mapping, and annotation. This study proposes a simple workflow of an in-house easy-to-purify Tn5-based plasmid sequencing platform using a compact benchtop sequencer (AistSeq).