Remodeling of the Intra-Conduit Inflammatory Microenvironment to Improve Peripheral Nerve Regeneration with a Neuromechanical Matching Protein-Based Conduit

Peripheral nerve injury (PNI) remains a challenging area in regenerative medicine. Nerve guide conduit (NGC) transplantation is a common treatment for PNI, but the prognosis of NGC treatment is unsatisfactory due to 1) neuromechanical unmatching and 2) the intra-conduit inflammatory microenvironment (IME) resulting from Schwann cell pyroptosis and inflammatory-polarized macrophages. A neuromechanically matched NGC composed of regenerated silk fibroin (RSF) loaded with poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (P:P) and dimethyl fumarate (DMF) are designed, which exhibits a matched elastic modulus (25.1 ± 3.5 MPa) for the peripheral nerve and the highest 80% elongation at break, better than most protein-based conduits. Moreover, the NGC can gradually regulate the intra-conduit IME by releasing DMF and monitoring sciatic nerve movements via piezoresistive sensing. The combination of NGC and electrical stimulation modulates the IME to support PNI regeneration by synergistically inhibiting Schwann cell pyroptosis and reducing inflammatory factor release, shifting macrophage polarization from the inflammatory M1 phenotype to the tissue regenerative M2 phenotype and resulting in functional recovery of neurons. In a rat sciatic nerve crush model, NGC promoted remyelination and functional and structural regeneration. Generally, the DMF/RSF/P:P conduit provides a new potential therapeutic approach to promote nerve repair in future clinical treatments.

[Analysis of contents of different kinds of fatty acids in carotid atherosclerotic plaques]

Objective: To analyze the contents of different kinds of fatty acids in carotid atherosclerotic plaques. Methods: A total of 24 patients who underwent carotid endarterectomy at the Second Affiliated Hospital of Naval Medical University from October 2021 to September 2022 due to moderate and severe carotid artery stenosis were retrospectively enrolled, including 20 males and 4 females, with a median age[M(Q1, Q3)] of 68.5 (63.5, 72.3) years. According to the symptoms of cerebral ischemia, the patients were divided into a symptomatic group (12 cases) and an asymptomatic group (12 cases). Regarding the pathological characteristics, the patients were divided into a stable group (14 cases) and a vulnerable group (10 cases) according to carotid plaque pathology scores. The expression differences of different types of fatty acids in carotid plaques were analyzed by targeted fatty acid metabolomics technology based on ultra-performance liquid chromatography-mass spectrometry (UPLC-ESI-MS/MS) analysis. Results: In the 24 samples, the median amount of fatty acids [M (Q1, Q3)] was 1 113 (330, 5 897) ng/g. A total of 13 medium and long-chain fatty acids were detected, including saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids. The content of saturated fatty acids was 584 (290, 9 888) ng/g, accounting for the highest proportion of 51.8%. The content of polyunsaturated fatty acids was 1 444 (393, 4 264) ng/g, accounting for 44.4%. The content of monounsaturated fatty acids was 2 793 (1 558, 3 247) ng/g, accounting for 3.8%. The contents of linoleic acid, α-linolenic acid and oleic acid in carotid plaques in the symptomatic group were 1 760 (581, 3 006), 682 (527, 886) and 2 081 (1 358, 2 907) ng/g, respectively, which were lower than those in the asymptomatic group 3 149 (2 226, 4 683), 1 423 (964, 2 270) and 3 178 (2 352, 3 993) ng/g (all P<0.05). The contents of linoleic acid, α-linolenic acid and oleic acid in carotid plaques in the vulnerable group were 1 537 (588, 2 921), 649 (477, 850) and 2 081 (1 129, 2 831) ng/g, respectively, which were lower than those in the stable group 3 149 (2 047, 4 416), 1 423 (940, 2 184) and 3 091 (2 201, 3 973) ng/g (all P<0.05). There were no significant differences in the contents of 11, 14-eicosadienoic acid, γ-linolenic acid, eicosapentaenoic acid, arachidonic acid, erucic acid, margaric acid, pentadecanoic acid, stearic acid, dodecanoic acid and palmitic acid (all P>0.05). Conclusions: Saturated fatty acids are the main type in carotid plaques. The contents of oleic acid, α-linolenic acid and linoleic acid decrease in vulnerable plaques.

Excessive mechanical strain accelerates intervertebral disc degeneration by disrupting intrinsic circadian rhythm

Night shift workers with disordered rhythmic mechanical loading are more prone to intervertebral disc degeneration (IDD). Our results showed that circadian rhythm (CR) was dampened in degenerated and aged NP cells. Long-term environmental CR disruption promoted IDD in rats. Excessive mechanical strain disrupted the CR and inhibited the expression of core clock proteins. The inhibitory effect of mechanical loading on the expression of extracellular matrix genes could be reversed by BMAL1 overexpression in NP cells. The Rho/ROCK pathway was demonstrated to mediate the effect of mechanical stimulation on CR. Prolonged mechanical loading for 12 months affected intrinsic CR genes and induced IDD in a model of upright posture in a normal environment. Unexpectedly, mechanical loading further accelerated the IDD in an Light-Dark (LD) cycle-disrupted environment. These results indicated that intrinsic CR disruption might be a mechanism involved in overloading-induced IDD and a potential drug target for night shift workers.

Working long shifts at times when the body should be at rest can have lasting effects on the intervertebral discs in the back, leading to chronic pain. Night shift workers are susceptible to developing certain health conditions because of chronic disruption to their circadian rhythms. Now, Li-Bo Jiang at Zhongshan Hospitial, Fudan University in Shanghai and co-workers across China have uncovered a link between circadian rhythm disruption and intervertebral disc degeneration. In experiments on human tissue samples and rat models, the team found that oscillation of the expression of clock-related genes and proteins was reduced in severely degenerated disc cells. Cellular clock mechanisms were disrupted in disc cells that had been repeatedly placed under mechanical strain at night. This disruption appears to influence degradation of the extracellular matrix, which the team believe may in turn accelerate disc degeneration.

Decorin inhibits nucleus pulposus apoptosis by matrix-induced autophagy via the mTOR pathway

Decorin (Dcn) is a member of the class I small leucine-rich proteoglycans, whose expression in the nucleus pulposus (NP) of intervertebral discs (IVDs) has been shown to increase with aging in humans and sheep. Dcn induces autophagy in endothelial cells; however, its precise role in NP and IVD degeneration during aging is not well understood. We addressed this question in the present study by treating rat nucleus pulposus cells (NPCs) with different concentrations of Dcn. The Western blot analysis and terminal deoxynucleotidyl transferase dUTP nick end labeling assay results showed that Dcn treatment induced autophagy and decreased apoptosis caused by interleukin (IL)-1β application. This effect was dependent on the protein kinase B/mechanistic target of rapamycin (mTOR)/p70 S6 kinase signaling. Dcn treatment also decreased the expression of matrix metalloproteinase-3 and -13 and decreased the IL-1β-induced attenuation of collagen type II and aggrecan levels. The role of Dcn in stimulating autophagy was further supported by the fact that the observed effects were abrogated by knocking down autophagy-related protein 7 with Atg7 small interfering RNA. Thus, Dcn protects NPCs in IVDs from IL-1β-induced apoptosis and degeneration by promoting autophagy through mTOR signaling.

[IgG4-related lung disease: analysis of 8 cases and literature review]

Objective: To improve the understanding and treatment of IgG4-related lung disease (IgG4-RLD). Methods: The clinical characteristics, serum IgG4 levels, pathological features, chest CT, therapy and prognosis of 8 patients with IgG4-RLD were retrospectively analyzed. These patients were admitted to the People's Liberation Army General Hospital and the pathological diagnosis was made between December 2005 and March 2016. Relevant literatures were reviewed. Results: The 8 patients with IgG4-RLD included 4 men and 4 women, with an average age of (59±4) years (range, 37-74). The respiratory symptoms included shortness of breath, cough, and expectoration. Extra-pulmonary symptoms included abdominal pain, facial edema, and fever. Extrapulmonary organs were involved in 7 cases. Serum IgG4 levels were elevated in 8 cases, with an average concentration of(17±6)g/L. Chest CT showed solid lung nodules in 6, alveolar-interstitial infiltration in 5, bronchovascular lesions in 3 and ground glass shadows in 2 cases. PET/CT was performed in 2 cases and it showed multiple organ involvement with higher radioactivity uptake(SUVmax2.9-4.2). The pathological examination found lymphocyte and plasma cell infiltration in 7, fibrous tissue hyperplasia in 5, and occlusive vasculitis in 2 cases. On immunohistochemical staining, the ratio of IgG4-positive plasma cells to IgG-positive plasma cells was higher than 40%in 3 cases. The number of IgG4-positive plasma cells was 10-50/HP in 8 cases. The misdiagnosis rate was 100% before the final diagnosis was made. Three cases received glucocorticoids with immunosuppressant therapy, 2 received surgery combined with glucocorticoid therapy, 2 received glucocorticoid therapy alone, and 1 only received surgery. The follow-up time was 4-132 months, with remission in 7 cases, and disease progression in 1 case, but no death. A total of 195 cases of IgG4-RLD were reviewed from the literature, among whom 111 cases were admitted with respiratory symptoms, 144 with extra-pulmonary involvement. Serum IgG4 levels were detected in 179 cases, with an average concentration of 5.408 g/L. The nodular type was predominant, accounting for 36.9%. Of these cases, 178 received glucocorticoid treatment with disease remission. Conclusions: The major clinical manifestations of IgG4-RLD were shortness of breath, cough and expectoration. Multiple organ lesions were common. The misdiagnosis rate was extremely high. The diagnosis could be made based on pathological features and IgG4 serum levels . Glucocorticoid treatment was effective.

Experimental study of airway pressure release ventilation in the treatment of acute respiratory distress syndrome

Airway pressure release ventilation (APRV) is a ventilator mode which has demonstrated potential benefits in acute respiratory distress syndrome (ARDS) patients. We therefore sought to compare relevant pulmonary data and safety outcomes of this mode to the conventional ventilation and sustained inflation. Canines admitted after intravenous injection of oleic acid requiring mechanical ventilation were randomly divided into 3 groups (n=6), namely conventional ventilation group, low tidal volume ventilation with recruitment group (LTV+SI) and APRV group. The changes of oxygenation, ventilation, airway pressure, inflammatory reaction and hemodynamics at the basic state were observed at 0, 1, 2 and 4 h during the experiment. The levels of PaO₂/FiO₂ in APRV group were higher than LTV+SI group at 2 and 4 h (P<0.05). In APRV group, the PCO₂ levels at 1, 2 and 4 h is much lower than LTV+SI group (P<0.05). Outcome variables showed no differences between APRV, LVT+SI and conventional mechanical ventilation for plateau airway pressure (24±1 vs. 29±3 vs. 25±4), mean arterial pressure (92.9±16.5 vs. 85.8±21.4 vs. 88.7±24.4), cardiac index (4.3±1.7 vs. 3.5±1.9 vs. 3.4±2.1), ERO₂ (13.4±10.3 vs. 16.1±6.8 vs. 17.6±9.1), lac (2.5±1.7 vs. 3.1±1.6 vs. 3.9±1.9), tumor necrosis factor (TNF)-α (132±11 vs. 140±6 vs. 195±13) and matrix metalloproteinase (MMP)-9. For canines sustaining acute respiratory distress syndrome requiring mechanical ventilation, APRV can significantly improve oxygenation and keep hemodynamic stability compared with LTV+SI. The results of TNF-α and MMP-9 suggest that APRV could be as protective for ARDS as LTV with recruitment group.

Effect of the Shenfu Injection Combined with Early Goal-Directed Therapy on Organ Functions and Outcomes of Septic Shock Patients

Shenfu injection (SFI) derived from traditional Chinese medicine has been widely used in cardiovascular diseases. The objective of this study was to determine the effect of SFI and conventional early goal-directed therapy (EGDT) on organ functions and outcomes of septic shock patients. For this purpose, a total of 45 septic shock patients were randomly divided into control group A (24 patients on EGDT) and experimental group B (21 patients on SFI + EGDT). SFI was administered (100@20 mL/h) twice daily. Hemodynamic status, lactic acid, and vasoactive drug use were observed before and after treatment. Other indicators included ventilator weaning time, ICU stay time, free of organ failure time, and 28-day hospital mortality. Regarding experimental group, compared with controls, BUN/creatinine decreased significantly at 3, 5, and 7 days while PaO2/FiO2 increased at 1 and 3 days (P < 0.05). APACHE-II and SOFA scores decreased in both groups at 3, 5, and 7 days (P < 0.05), whereas SOFA scores improved more in experimental group as compared with controls. Ventilator weaning time and ICU stay were significantly shorter in experimental group as compared with controls. In both groups, mean arterial pressure/systemic vascular resistance index post-treatment levels increased and lactic acid decreased at 6, 12, 24, 48, and 72 h (P < 0.05). Heart rate decreased at 24, 48, and 72 h (P < 0.05); while gamma-glutamyl transpeptidase and glutamate oxaloacetate transaminase levels increased at 1 day and 1 and 3 days, respectively (P < 0.05). Combined use of SFI and EGDT can improve hemodynamics, reduce the damage to vital organs, and shorten ventilation and ICU stay times in septic shock patients.

Determination of Imazaquin and its metabolite by liquid chromatography-quadrupole-time of flight tandem mass

A method consisting of solvent extraction followed by liquid chromatography-quadrupole-time of flight- tandem mass spectrometry analysis was developed for the identification of Imazaquin and its metabolite. The relationships between detector response and sample concentrations showed a high degree of linearity (r > 0.998) over the range 0.03-10 microg/g. The recoveries obtained were in the acceptable range of 86%-104% between spiked. The relative standard deviation of this method was 6.4%-17.1%. A 35-day study of Imazaquin degradation was taken in agricultural soil from Binzhou, China. The degradation followed first order kinetics (C = 0.7672e(-0.0774t)), with half-life of less than 8.5 days. Investigation of the by-products from liquid chromatography-quadrupole-time of flight- tandem mass spectrometry has shown that there were four important metabolites 4-methylene-2-(quinolin-2-yl)-1H-imidazol-5(4H)-one, quinoline-3-carbaldehyde, 1-amino-2,3-dimethyl-1-oxobutan-2-ylium and 1H-[1,2]oxazino[4,5-b]quinolin-1-one in the degradation process. The accurate mass measurements error was 5 ppm in this study. The method was successfully applied to the analysis of imazaquin and its metabolite residues in soil.

Application of finite-element analysis with optimisation to assess the in vivo non-linear myocardial material properties using echocardiographic imaging

An application of finite-element analysis with an optimisation technique to assess the myocardial material properties in diastasis in vivo is described. Using the data collected from an animal model, the three-dimensional geometry of the left ventricular chamber, at several times in diastole, was reconstructed. From the measurement of the ventricular chamber pressure during image acquisition, finite-element analysis was performed to predict the expansion during diastasis. Initially, by restricting the motion of the epicardial nodes and computing the reaction forces, an 'equivalent pericardial pressure' was determined and applied in subsequent analysis. The duration of diastasis was divided into three or four intervals and the analysis was performed at each interval to assess the material properties of the myocardium. Using such a step-wise linear approach, the non-linear material properties of the myocardium during passive expansion was determined. Our results demonstrated that the computed 'equivalent pericardial pressure' increased with and was smaller than the corresponding left ventricular chamber pressure. The passive myocardium exhibited a linear tangent modulus against chamber pressure relationship which is equivalent to an exponential stress/strain relationship, similar to those suggested by in vitro studies.