Bioengineering最新文献

When nerves are severed, such as during traumatic injury, an acute injury state is induced, characterized by biological and physical changes in the proximal and distal stumps. Beyond the initial injury phase, over a time frame of weeks to months, nerves that remain unrepaired progressively enter a chronic injury state, characterized by a change in the extracellular matrix structure of the distal stump, the down-regulation of neurotrophic factors and the loss of macrophages' and Schwann cells' ability to clear out degraded axons and myelin. There are also potential systemic impacts away from the site of injury, including in end organs such as muscle and bone. The literature suggests that several of these processes may be strongly influenced by innate and adaptive immune system responses, including a major role for complement pathways. This review details evidence in favor of such a possibility, as well as knowledge gaps and areas for future investigation.

Background: Extracellular vesicles (EVs) have emerged as promising cell-free therapeutic agents in regenerative medicine due to their ability to deliver bioactive molecules with enhanced stability and low immunogenicity. Their potential to replicate stem cell functions without the risks of live-cell transplantation has catalyzed a surge in global research.

Objective: This study aims to perform a scientometric analysis of EV-based regenerative medicine research from 2014 to 2024, identifying publication trends, influential contributors, thematic clusters, and translational challenges.

Methods: Data were retrieved from the Web of Science Core Collection and analyzed using CiteSpace software. The analysis included journal impact mapping, co-authorship networks, co-citation analysis, and thematic cluster identification. Metrics such as citation bursts, total link strength, and silhouette values were used to assess influence and thematic coherence.

Results: The most prolific journals were Stem Cell Research & Therapy and International Journal of Molecular Sciences. China led in publication volume, while the USA dominated citation impact. Foundational works by Théry and Lai, including the MISEV guidelines, shaped methodological standards. Nine thematic clusters were identified, including oxidative stress, small EVs, mesenchymal stromal cells, muscle regeneration, and chronic kidney disease. A strategic shift toward engineered EVs and novel sources such as iPSCs and macrophages was evident. Key translational barriers include lack of standardization, scalability issues, and regulatory ambiguity.

Conclusions: EV-based therapies are transitioning from foundational research to clinical application. Overcoming methodological and regulatory challenges will be critical to realizing their full therapeutic potential in regenerative medicine.

Basal cell carcinoma (BCC) is the most frequent skin cancer, and surgery remains the treatment of choice, particularly in high-risk subtypes and sites. However, in low-risk cases and in patients where cosmetic outcome is a priority, alternative strategies, including laser therapy, have been proposed. Different laser sources offer potential advantages in terms of minimal invasiveness, healing time, and cosmetic outcome, but their clinical role remains a matter of debate. This narrative review critically analyses the available evidence on the use of lasers in the treatment of basal cell carcinoma, with a focus on ablative lasers, vascular lasers, and laser-assisted photodynamic therapy. Mechanisms of action, main clinical results, limitations, and the emerging contribution of non-invasive imaging for case selection and response monitoring are discussed. Ablative lasers, in particular CO₂, show favourable results in superficial low-risk BCC, while clearance reliability decreases with increasing tumour depth. Vascular lasers may offer short-term control in selected lesions but with limited long-term data. Laser-assisted PDT represents a promising strategy to extend the indication of PDT to selected nodular forms. Overall, the literature is limited by methodological heterogeneity, incomplete stratification, and short follow-ups. Well-designed comparative studies, standardised protocols, and objective controls will be essential to define the real clinical space of laser therapy in basal cell carcinoma.

Quantitative magnetic resonance imaging has increasingly highlighted white matter abnormalities as a key component of affective disorders. Fast macromolecular proton fraction (MPF) mapping, a myelin-sensitive technique, recently revealed divergent patterns of white matter myelination in bipolar disorder (BD) and recurrent depressive disorder (RDD), with reduced MPF in RDD but elevated MPF in BD. These findings challenge uniform hypomyelination models of mood disorders. In this Communication, we propose a trajectory-oriented reinterpretation of these results, suggesting that MPF differences may reflect distinct neurodevelopmental and lifespan-related myelination trajectories rather than a simple marker of tissue damage. Elevated MPF in BD-observed particularly in relatively young patients-may indicate accelerated or dysregulated white matter maturation or activity-dependent myelin plasticity, whereas reduced MPF in RDD may reflect impaired maintenance of myelin integrity. We emphasize that MPF should not be interpreted as a unidirectional index of pathology and argue that it may serve as a phenotype-differentiating biomarker between BD and RDD, warranting further longitudinal and multimodal studies.

Background: Hyperbaric oxygen therapy (HBOT) has regenerative effects in various tissues, but its impact on hair follicles is unclear. This preliminary study evaluated HBOT-induced changes in hair and scalp characteristics in healthy adults. Methods: Nine healthy volunteers completed 50 HBOT sessions over three months (2.0 ATA, 100% oxygen, 90 min per session). Objective assessments included follicle density, hairs per follicle, hair volume, and shaft thickness using the Becon phototrichogram system. Subjective evaluations were conducted via a 7-point Likert questionnaire on scalp appearance, hair density, thickness, growth, and shedding. Pre- and post-treatment data were compared using paired statistical tests. Results: Positive trends were observed in follicle density (61.3→66.8 counts/cm²), hairs per follicle (1.24→1.33), and hair volume (24.9→27.7%), though not statistically significant. Hair shaft thickness decreased significantly (0.18→0.10 mm, p = 0.011), consistent with early anagen-phase regrowth. Subjective assessments showed significant improvements across all domains (p < 0.05). Scalp imaging visually supported these findings. Conclusions: HBOT may enhance hair follicle activation and scalp health in healthy adults. These preliminary findings justify further controlled studies to explore HBOT as a non-pharmacological approach to hair regeneration.

Background: Stress urinary incontinence (SUI) is one of the most common pelvic floor disorders in women, often impairing quality of life (QoL). Pelvic floor muscle training (PFMT) is the standard conservative therapy, while autologous platelet-rich plasma (PRP) is a newer minimally invasive regenerative option.

Objective: To compare the effectiveness of three periurethral PRP injections versus PFMT in women with SUI.

Methods: This prospective cohort study included 169 women diagnosed with SUI, divided into a PRP group (n = 131), receiving three periurethral PRP injections at 4-6-month intervals, and a PFMT group (n = 38), completing a 12-week PFMT program. Outcomes were measured using the Stamey incontinence scale, visual analogue scale (VAS), and the King's Health Questionnaire (KHQ).

Results: At baseline, PRP patients had more severe symptoms and worse QoL scores. After one injection, PRP achieved improvements in Stamey and VAS scores comparable to PFMT (lower scores), though KHQ remained superior in PFMT (significantly higher baseline scores in the PRP group than the PFMT group). The PRP group showed consistently larger within-group improvements across all scales (p < 0.001), in contrast to the PFMT group, which produced smaller and less consistent changes.

Conclusions: Repeated PRP treatment provides greater, controlled, and more consistent benefits than PFMT for SUI.

Background: Arterial stenosis produces nonlinear changes in vascular impedance that are challenging to investigate in real time using either benchtop flow phantoms or high-fidelity computational fluid dynamics (CFD) models.

Objective: This study aimed to develop and evaluate a low-cost printed circuit board (PCB) analog capable of reproducing the hemodynamic effects of progressive arterial stenosis through an R-L-C mapping of vascular mechanics.

Methods: A lumped-parameter (0D) electrical network was constructed in which voltage represented pressure, current represented flow, resistance modeled viscous losses, capacitance corresponded to vessel compliance, and inductance represented fluid inertance. A variable resistor simulated focal stenosis and was adjusted incrementally to represent progressive narrowing. Input U_in, output U_out, peak-to-peak V_pp, and mean V_avg voltages were recorded at a driving frequency of 50 Hz. Physiological correspondence was established using the canonical relationships. R=8μlπr4, L=plπr2, C=3πr32Eh, where μ is blood viscosity, ρ is density, E is Young's modulus, and h is wall thickness. A calibration constant was applied to convert measured voltage differences into pressure differences.

Results: As simulated stenosis increased, the circuit exhibited a monotonic rise in U_out and V_pp, with a precise inflection beyond mid-range narrowing-consistent with the nonlinear growth in pressure loss predicted by fluid dynamic theory. Replicate measurements yielded stable, repeatable traces with no outliers under nominal test conditions. Qualitative trends matched those of surrogate 0D and CFD analyses, showing minimal changes for mild narrowing (≤25%) and a sharp increase in pressure loss for moderate to severe stenoses (≥50%). The PCB analog uses a simplified, lumped-parameter representation driven by a fixed-frequency sinusoidal excitation and therefore does not reproduce fully characterized physiological systolic-diastolic waveforms or heart-arterial coupling. In addition, the present configuration is intended for relatively straight peripheral arterial segments and is not designed to capture the complex geometry and branching of specialized vascular beds (e.g., intracranial circulation) or strongly curved elastic vessels (e.g., the thoracic aorta).

Conclusions: The PCB analog successfully reproduces the characteristic hemodynamic signatures of arterial stenosis in real time and at low cost. The model provides a valuable tool for educational and research applications, offering rapid and intuitive visualization of vascular behavior. Current accuracy reflects assumptions of Newtonian, laminar, and lumped flow; future work will refine calibration, quantify uncertainty, and benchmark results against physiological measurements and full CFD simulations.

Background: Intervertebral motion is a fundamental aspect of spinal biomechanics, crucial for understanding lumbar spine function, pain mechanisms, and surgical outcomes. Various methods exist for measuring and interpreting it, each with its own advantages, limitations, and specific applications. However, a comprehensive and standard taxonomy of study types for the measurement and interpretation of in vivo intervertebral motion in the lumbar spine is lacking.

Objectives: This review aimed to systematically identify, characterise, and categorise the diverse study types deposited in the literature.

Eligibility criteria: Only studies in English and of lumbar spine intervertebral motion in living subjects were considered, and only those that employed objective measurement of motion sequences were included.

Sources of evidence: A comprehensive literature search was performed in PubMed, CINAHL, and SCOPUS for articles published between January 2000 and October 2025.

Charting methods: After removal of duplicates, all studies were subjected to Title and abstract screening, followed by full-text screening of potentially eligible studies. Data selected were charted into tables under the headings: author, year, country, purpose, technology, participants, measurement, interpretation, radiation dosage, and significance of findings.

Results: Forty-nine studies were abstracted and are described under 11 study types. These formed a taxonomy constituting the following six categories: normal biomechanical mechanisms, pathological and injury mechanisms, direct kinematic measurement, spinal stabilisation, dynamic radiography, and clinical markers. The resulting taxonomy will serve as a resource for researchers, clinicians, and policymakers by facilitating a more coherent understanding of the field and promoting standardisation in research design and reporting.

Background: Traditional high-speed mechanical osteotomes cause substantial thermal and mechanical trauma, impairing bone healing. Erbium-doped yttrium-aluminum-garnet (Er:YAG) lasers, with water-mediated non-contact ablation, offer precise osteotomy potential with minimal collateral damage. This study demonstrated the feasibility of Er:YAG laser use for complex osteotomies and elucidated its multi-scale biological impacts on bone.

Methods: A custom Er:YAG laser performed Z/arc-shaped osteotomies on fresh ovine bone (oscillating saw as control); paired rat tibial osteotomies; and compared laser vs. saw resection. Osteotomy surfaces were characterized by SEM/micro-CT; histological staining quantified thermal/mechanical damage. Bone marrow-derived mesenchymal stem cell (BMSC) adhesion, viability, and infiltration on cut surfaces were evaluated via LSCM.

Result: In the ex vivo ovine model, the Er:YAG laser enabled precise execution of complex osteotomies (Z-shaped and arc-shaped), producing significantly narrower gaps than the oscillating saw (1.14 mm vs. 2.70 mm, p < 0.001) with high geometric fidelity and smooth surfaces free of burrs, micro-cracks, or debris. In the in vivo rat model, laser ablation simultaneously minimized both thermal and mechanical damage at the osteotomy interface: it reduced the thermal damage depth (154 vs. 592 µm, p < 0.001) and empty lacunae rate (16.8% vs. 41.8%, p < 0.001) while completely avoiding the mechanical damage zone (297 µm) induced by sawing. Furthermore, the laser-ablated surface established a highly bioactive interface, which significantly enhanced the adhesion (606 vs. 389 cells), viability (86.9% vs. 46.6%), and infiltration depth (196 vs. 75 µm) of bone marrow-derived mesenchymal stem cells (all p < 0.001).

Conclusions: In conclusion, this proof-of-concept study demonstrates that the Er:YAG laser has the potential to enable precise bone resection while preserving microstructure. By establishing a pro-regenerative microenvironment, this technology shows promise as a biologically favorable alternative to conventional sawing, although further technical refinement and long-term validation are essential for its clinical translation.

Background: Functional Electrical Stimulation (FES) for post-stroke drop foot is commonly applied in acute and subacute stroke rehabilitation or as part of long-term home-based programs in chronic patients. Evidence supporting short facility-based rehabilitation programs incorporating FES in chronic populations remains limited. The aim of this study was to explore functional outcomes associated with such a program in a chronic population.

Materials and methods: A 10-day facility-based rehabilitation program incorporating FES therapy followed by 3-month follow-up was delivered to 14 chronic post-stroke patients with foot drop (8 women; aged 62.6 ± 12.2 years). FES was applied during walking with stimulation synchronized to the swing phase of gait (35 Hz, 300 μs, 15 min per session). Activities of daily living and mobility were assessed using clinical outcome measures. Statistical significance (p < 0.05), effect sizes, and minimal clinically important difference (MCID) responder rates were evaluated.

Results: Statistically significant improvements were observed across all outcome measures post-treatment and at follow-up, with MCID responder rates exceeding 50%.

Conclusions: A short facility-based multimodal rehabilitation program incorporating FES was associated with functional improvements in chronic post-stroke patients. Given the multimodal design, these findings cannot be attributed to FES alone and should be interpreted as exploratory.