The Impacts of Nirmatrelvir-Ritonavir on Myocardial Injury and Long-Term Cardiovascular Outcomes in Hospitalized Patients with COVID-19 amid the Omicron Wave of the Pandemic.

PURPOSE: Even though nirmatrelvir-ritonavir can improve the short-term morbidity and mortality in COVID-19 patients, the effects of this treatment on long-term major adverse cardiovascular events (MACEs), especially myocardial injury, remains undetermined. METHODS: This prospective cohort study identified hospitalized adult patients with COVID-19 between April 19, 2022, and June 9, 2022, amid the omicron wave of the pandemic. Matched nirmatrelvir-ritonavir-treated and non-treated cohorts were formed using the propensity score matching method. The primary outcome of this study was the incidence of MACEs (cardiovascular death, myocardial infarction, stroke, new-onset heart failure or heart failure hospitalization or ventricular arrhythmia) from 30 days to 16 months after the diagnosis of COVID-19. RESULTS: Two 949-patient cohorts with balanced baseline characteristics were formed by propensity score matching. Patients with nirmatrelvir-ritonavir, compared to those untreated, had a lower level of troponin I peak as well as the incidence of troponin I elevation. During the follow-up period, 59 patients in the nirmatrelvir-ritonavir group and 86 patients in the control group developed MACEs (P = 0.020). Regarding specific constituents of MACEs, the differences are mainly reflected in new-onset heart failure or heart failure hospitalization. COVID-19 clinical severity and troponin I peak were the independent predictors, while nirmatrelvir-ritonavir was the independent protective factor for the occurrence of MACEs in this population. CONCLUSION: Nirmatrelvir-ritonavir was effective in reducing myocardial injury as well as long-term adverse cardiovascular outcomes among hospitalized patients with COVID-19 amid the omicron wave of the pandemic.

Effect of lgals3a on embryo development of zebrafish.

Our study was aimed to investigate the effects of lgals3a (Gal-3 encoding gene) on the development of zebrafish embryo and its underlying mechanisms. Morpholino (MO) technology was used to inhibit the expression of zebrafish lgals3a, and the effect of lgals3a gene knockdown on zebrafish embryo development and the number of monocyte macrophages was observed. Effect of lgals3a-e3i3-MO on apoptosis of zebrafish was detected by acridine orange staining. In addition, the mRNA expression levels of Wnt/ß-catenin signaling pathway-related genes were detected by RT-qPCR. Compared with control-MO group, the zebrafish embryos injected with lgals3a-e3i3-MO had obvious defects in the head, eyes, and tail, and pericardial edema. Lgals3a-e3i3-MO significantly reduced the number of mononuclear macrophages in zebrafish embryos compared with the control-MO group. The results of acridine orange staining showed that compared with the control-MO group, lgals3a-e3i3-MO promoted cardiomyocyte apoptosis in zebrafish. Furthermore, lgals3a-e3i3-MO significantly up-regulated the expression of dkk1b, wnt9a, lrp5, fzd7a, ß-catenin, Gsk-3ß, mycn, myca in the Wnt/ß-catenin pathway, and decreased the expression of lef1. These results indicate that lgals3a-e3i3-MO inhibits zebrafish embryo development, reduces the number of mononuclear macrophages, activates Wnt/ß-catenin signaling pathway and promotes cardiomyocyte apoptosis.

MicroRNA-146a protects against myocardial ischaemia reperfusion injury by targeting Med1.

BACKGROUND: Myocardial ischaemia reperfusion injury (MIRI) is a difficult problem in clinical practice, and it may involve various microRNAs. This study investigated the role that endogenous microRNA-146a plays in myocardial ischaemia reperfusion and explored the possible target genes. METHODS: MIRI models were established in microRNA-146a deficient (KO) and wild type (WT) mice. MicroRNA-146a expression was evaluated in the myocardium of WT mice after reperfusion. The heart function, area of myocardium infarction and in situ apoptosis were compared between the KO and WT mice. Microarray was used to explore possible target genes of microRNA-146a, while qRT-PCR and dual luciferase reporter assays were used for verification. Western blotting was performed to detect the expression levels of the target gene and related signalling molecules. A rescue study was used for further testing. RESULTS: MicroRNA-146a was upregulated 1 h after reperfusion. MicroRNA-146a deficiency decreased heart function and increased myocardial infarction and apoptosis. Microarray detected 19 apoptosis genes upregulated in the KO mice compared with the WT mice. qRT-PCR and dual luciferase verified that Med1 was one target gene of microRNA-146a. TRAP220, encoded by Med1 in the KO mice, was upregulated, accompanied by an amplified ratio of Bax/Bcl2 and increased cleaved caspase-3. Inhibition of microRNA-146a in H9C2 cells caused increased TRAP220 expression and more apoptosis under the stimulus of hypoxia and re-oxygenation, while knockdown of the increased TRAP220 expression led to decreased cell apoptosis. CONCLUSIONS: MicroRNA-146a exerts a protective effect against MIRI, which might be partially mediated by the target gene Med1 and related to the apoptosis signalling pathway.

Inferior displacement of greater tuberosity fracture suggests an occult humeral neck fracture: a retrospective single-centre study.

PURPOSE: To radiographically characterize the relationship between inferior displacement of great tuberosity (GT) fracture and associated occult or minor displaced humeral neck fracture. METHODS: Thirty patients with inferior displacement of the GT on the initial anterior-posterior (AP) view X-ray were included in this study. Twenty-four patients received further computed tomography (CT) scans. One patient with negative CT scans underwent MRI. Radiographic indexes included the cervico-diaphyseal angle, the distance of the inferior displacement of the GT fracture, the apex-tuberosity distance, and the direction of the GT shift on the 3D-CT scan. The measurement reliability was analyzed by calculating intra-class correlation (ICC) coefficients. The relationships between the parameters were revealed using Pearson correlation analysis. RESULTS: In the 30 cases, humeral neck fractures were detected by AP view X-ray (6 cases), CT (23 cases), and MRI (1 case). The mean cervico-diaphyseal angle was 146.7° ± 8.9°. The mean inferior displacement of the GT fracture was 13.4 ± 5.9 mm. The mean apex-tuberosity distance was 11.8 ± 2.8 mm. Posterior/inferior displacement of the GT fractures was observed in 24 patients via CT scan. All the evaluated parameters presented correlations among methods, indicating intra-rater and inter-rater reliability. The Pearson correlation analysis revealed that inferior displacement of GT fracture was correlated with the cervico-diaphyseal angle (P < 0.05). CONCLUSION: The inferior displacement of GT fracture on AP view X-ray is a useful diagnostic clue for the early recognition of occult humeral neck fracture and may indicate the need for further CT/MRI examination.

Circulating Galectin-3 is Associated With Left Atrial Appendage Remodelling and Thrombus Formation in Patients With Atrial Fibrillation.

BACKGROUND: Left atrial appendage (LAA) is gaining increasing attention in patients with atrial fibrillation (AF) in the context of cardioembolic stroke. Galectin-3 (Gal-3) is a mediator of profibrotic pathways and is associated with an increased incidence of heart failure. However, the role of Gal-3 in LAA remodelling and thrombus formation in AF has not been evaluated. METHODS: This prospective study included 153 consecutive patients with paroxysmal (n=58), persistent (n=55) or permanent (n=40) nonvalvular AF. The serum level of Gal-3 was measured by enzyme-linked immunosorbent assay. The morphology and function of LAA were determined by transoesophageal echocardiography. RESULTS: Left atrial appendage thrombus was observed in 22 patients (2 in paroxysmal AF, 11 in persistent AF and 9 in permanent AF). Significant differences among patients with different types of AF were found in terms of LAA morphology (orifice diameter and depth) and function (flow velocity and tissue Doppler contracting velocity) as well as serum levels of Gal-3. Furthermore, patients with persistent or permanent AF had higher levels of Gal-3. High Gal-3 level was closely related to LAA flow velocity and occurrence of LAA thrombus. Multivariate logistic regression analysis revealed that Gal-3 was an independent determinant of LAA thrombus in patients with AF. Receiver operating characteristic (ROC) curves related to LAA thrombus formation established a cut-off point for Gal-3 >18.95ng/ml. CONCLUSIONS: Cardiac rhythm disturbances caused by AF may lead to morphologic and functional remodelling of LAA. The serum level of Gal-3 was significantly correlated with LAA remodelling in patients with AF. High levels of Gal-3 were also a predicator for LAA thrombus formation.

MicroRNA-9 Inhibits NLRP3 Inflammasome Activation in Human Atherosclerosis Inflammation Cell Models through the JAK1/STAT Signaling Pathway.

BACKGROUND/AIMS: MicroRNA-9 (miR-9) is involved in inflammatory reaction in atherosclerosis; however, its function and regulatory mechanisms remain unclear. We aimed to uncover the exact roles of miR-9 and downstream signaling pathways using in vitro human atherosclerosis models. METHODS: We used oxidized low-density lipoprotein (oxLDL)-stimulated human THP-1 derived macrophages, oxLDL-stimulated human primary peripheral blood monocytes and lipopolysaccharides (LPS) or Alum-stimulated human THP-1 derived macrophages as in vitro atherosclerosis inflammation models. Transient transfection of over-expression vectors, small interference RNAs (siRNAs) or antisense oligonucleotides was used to regulate intracellular protein or miR-9 levels. Cell responses and signal transduction were detected by multiple assays including Western blotting, enzyme-linked immunosorbent assay (ELISA) and luciferase reporter assay. RESULTS: MiR-9 inhibited while anti-miR-9 antisense oligonucleotides induced interleukin-1 beta (IL-1ß) and NLRP3 inflammasome activation in all in vitro models. Janus kinase 1 (JAK1) and matrix metalloproteinase 13 (MMP-13) were identified as the target genes of miR-9. In oxLDL-stimulated human THP-1 derived macrophages, knockdown of JAK1 by siRNA blocked the phosphorylation of signal transducer and activator of transcription 1 (STAT1) and mimicked the effects of miR-9. In the same model, JAK1 knockdown blocked the phosphorylation of NF-κB p65 in the nuclei and the phosphorylation of NF-κB IκBα in the cytoplasm. CONCLUSIONS: Our study demonstrated that miR-9 could inhibit activation of the NLRP3 inflammasome and attenuate atherosclerosis-related inflammation, likely through the JAK1/STAT1 signaling pathway. Therefore, miR-9 may serve as a potential therapeutic target for atherosclerosis.

Whole-Life-Stage Characterization in the Basic Biology of Daphnia magna and Effects of TDCIPP on Growth, Reproduction, Survival, and Transcription of Genes.

Toxicity tests of chemicals have mainly focused on the partial life-cycle evaluation of model animals. Limited information is available for the evaluation of effects of chemicals from a whole-life-stage exposure perspective. The objective of this study was to perform a whole-life-stage characterization in the basic biology of Daphnia magna (D. magna) and evaluate the effects of a known organophosphate ester (OPE) contaminant, tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), on growth, reproduction, survival, and transcription of genes. The whole-life-stage characterization in growth, reproduction, and survival of D. magna was conducted, and representative sampling time points for the three developmental stages were identified (day 6, day 32, and day 62). Transcriptomic profiles for these three stages were compared, and stage-specific PCR arrays of D. magna were developed. The whole-life-stage exposure to environmentally relevant or greater concentrations of TDCIPP significantly inhibited growth and reproduction of D. magna and decreased survival at the later stage of the exposure experiment (≥32 days). Such adverse effects were not observed in the early stage of the exposure (<32 days), suggesting that short-term toxicity tests, such as the standard 21-day test, might underestimate the environmental risk of TDCIPP. Furthermore, expressions of genes selected at day 6, day 32, and day 62 were significantly changed after TDCIPP exposure, and the changes in the expressions of partial genes were correlated to the inhibitory effects on growth, reproduction, and survival.

[Lipid-lowering effect of seven traditional Chinese medicine monomers in zebrafish system].

The present study aimed to study lipid-lowering effect of seven traditional Chinese medicine monomers in zebrafish system. Zebrafish were fed with high fat diet to establish a hyperlipemia model, then fasted and bathed with seven traditional Chinese medicine monomers stigmasterol, triacontanol, chrysophanol, vanillic acid, shikimic acid, polydatin and oleanolic acid respectively. The oil red O staining was used to detect the blood lipids of zebrafish. Serum total cholesterol and triglyceride levels were detected to validate the lipid-lowering effect. The result showed that a zebrafish model of hyperlipemia could be established by feeding larvae zebrafish with high fat diet. Among the seven traditional Chinese medicine monomers, chrysophanol had lipid-lowering effect. Chrysophanol significantly reduced serum total cholesterol and triglyceride levels in adult zebrafish fed with high fat diet. Chrysophanol accelerated peristalsis frequency of zebrafish intestine and the excretion of high fat food. It is concluded that chrysophanol has lipid- lowering effect in zebrafish, and the mechanism of the effect may be due to the roles of chrysophanol in reducing lipid absorption from gastrointestinal tract and accelerating the excretion of food.

A review on the effects of PBDEs on thyroid and reproduction systems in fish.

The objective of this review was to summarize and discuss the effects of Polybrominated diphenyl ethers (PBDEs) on thyroid and reproduction systems in fish. We reviewed the evidences and mechanisms for PBDEs-induced thyroid and reproduction disruption, as well as the cross-talk between the two systems in fish. In thyroid disruption, we mainly paid attention to the effects of PBDEs on hypothalamic-pituitary-thyroid (HPT) axis, thyroid hormones (THs) transport and metabolism, thyroid receptors (TRs) and thyroid follicle histology. In reproduction disruption, we focused on the effects of PBDEs on steroid hormone production, expression of genes involved in steroidogenesis, and gonadal development. Despite that there is an interaction between thyroid and reproductive systems in fish, it is still remains unclear that PBDE-induced reproductive impairments are caused by direct effects on hypothalamic-pituitary-gonadal (HPG) functioning or by indirect action through cross-talk between the two systems. Future studies are needed to explore the relationships between reproductive toxicity and thyroid system disruption after PBDEs exposure.

Quantitative T2 relaxation time and magnetic transfer ratio predict endplate biochemical content of intervertebral disc degeneration in a canine model.

BACKGROUND: Direct measurement of disc biochemical content is impossible in vivo. Therefore, magnetic resonance imaging (MRI) is used to evaluate disc health. Unfortunately, current clinical imaging techniques do not adequately assess degeneration, especially in the early stage of cartilage endplate, and subchondral bone zone (CEPZ). Therefore, this study aimed to investigate the sensitivity of quantitative MRI methods, namely T2 relaxation time and Magnetic Transfer Ratio (MTR), to identify early disc degeneration, especially for the CEPZ, using an experimental canine model of intervertebral disc injury and to investigate their sensitivity in depicting biochemically and histologically controlled degenerative changes in the disc. METHODS: Sixteen juvenile dogs underwent iatrogenic annular disruption via stab incisions. The animals underwent repeated 3.0 T MR imaging, and were sacrificed 4, 8, and 12 weeks post-operatively. A continuous rectangle drawing method was used to select regions of interest for the intervertebral disc from the cephalic to caudal CEPZ including the vertebrae, nucleus pulposus (NP) and annulus fibrosus (AF), which resembled pixel measurement for imaging analysis. Presence of degenerative changes was controlled by biochemical and histological analyses. The correlations between histological score, biochemical content, and quantitative MRI signal intensities were also analyzed. RESULTS: Both T2 relaxation time and MTR values changed for CEPZ, NP, and AF tissues within 12 weeks. T2 relaxation time values decreased significantly in the NP, AF, and CEPZ separately at pre-operation, 4, 8, and 12 weeks when compared each time (P < 0.05). MTR values showed no significant differences for the CEPZ between 8 and 4 weeks or 12 weeks, or compared to pre-operative values; there were significant differences for the AF. Biochemical and histological analysis showed changes consistent with quantitative MRI signal intensities for early stage degeneration. CONCLUSIONS: Early traumatic or degenerative changes are detectable with both T2 and MTR. T2 changes were more sensitive to the differences in disc status, especially for the CEPZ. Since T2 and MTR reflect different disc properties, performing both imaging under the same conditions would be helpful in the evaluation of disc degeneration. The continuous rectangle drawing can be a sensitive method to detect the changes of CEPZ.

Curcumin inhibits EMMPRIN and MMP-9 expression through AMPK-MAPK and PKC signaling in PMA induced macrophages.

In coronary arteries, plaque disruption, the major acute clinical manifestations of atherosclerosis, leads to a subsequent cardiac event, such as acute myocardial infarction (AMI) and unstable angina pectoris (UA). Numerous reports have shown that high expression of MMP-9 (matrix metalloproteinase-9), MMP-13 (matrix metalloproteinase-13) and EMMPRIN (extracellular matrix metalloproteinase induce) in monocyte/macrophage results in the plaque progression and destabilization. Curcumin exerts well-known anti-inflammatory and antioxidant effects and probably has a protective role in the atherosclerosis. The purpose of our study was to investigate the molecular mechanisms by which curcumin affects MMP-9, MMP13 and EMMPRIN in PMA (phorbol 12-myristate 13-acetate) induced macrophages. Human monocytic cells (THP-1 cells) were pretreated with curcumin or compound C for 1 h, and then induced by PMA for 48 h. Total RNA and proteins were collected for real-time PCR and Western blot analysis, respectively. In the present study, the exposure to curcumin resulted in attenuated JNK, p38, and ERK activation and decreased expression of MMP-9, MMP-13 and EMMPRIN in PMA induced macrophages. Moreover, we demonstrated that AMPK (AMP-activated protein kinase) and PKC (Protein Kinase C) was activated by PMA during monocyte/macrophage differentiation. Furthermore, curcumin reversed PMA stimulated PKC activation and suppressed the chronic activation of AMPK, which in turn reduced the expression of MMP-9, MMP-13 and EMMPRIN. Therefore, it is suggested that curcumin by inhibiting AMPK-MAPK (mitogen activated protein kinase) and PKC pathway may led to down-regulated EMMPRIN, MMP-9 and MMP-13 expression in PMA-induced THP-1 cells.

Exercise-Induced Reduction of IGF1R Sumoylation Attenuates Neuroinflammation in APP/PS1 Transgenic Mice.

INTRODUCTION: Alzheimer's Disease (AD), a progressive neurodegenerative disorder, is marked by cognitive deterioration and heightened neuroinflammation. The influence of Insulin-like Growth Factor 1 Receptor (IGF1R) and its post-translational modifications, especially sumoylation, is crucial in understanding the progression of AD and exploring novel therapeutic avenues. OBJECTIVES: This study investigates the impact of exercise on the sumoylation of IGF1R and its role in ameliorating AD symptoms in APP/PS1 mice, with a specific focus on neuroinflammation and innovative therapeutic strategies. METHODS: APP/PS1 mice were subjected to a regimen of moderate-intensity exercise. The investigation encompassed assessments of cognitive functions, alterations in hippocampal protein expressions, neuroinflammatory markers, and the effects of exercise on IGF1R and SUMO1 nuclear translocation. Additionally, the study evaluated the efficacy of KPT-330, a nuclear export inhibitor, as an alternative to exercise. RESULTS: Exercise notably enhanced cognitive functions in AD mice, possibly through modulations in hippocampal proteins, including Bcl-2 and BACE1. A decrease in neuroinflammatory markers such as IL-1ß, IL-6, and TNF-α was observed, indicative of reduced neuroinflammation. Exercise modulated the nuclear translocation of SUMO1 and IGF1R in the hippocampus, thereby facilitating neuronal regeneration. Mutant IGF1R (MT IGF1R), lacking SUMO1 modification sites, showed reduced SUMOylation, leading to diminished expression of pro-inflammatory cytokines and apoptosis. KPT-330 impeded the formation of the IGF1R/RanBP2/SUMO1 complex, thereby limiting IGF1R nuclear translocation, inflammation, and neuronal apoptosis, while enhancing cognitive functions and neuron proliferation. CONCLUSION: Moderate-intensity exercise effectively mitigates AD symptoms in mice, primarily by diminishing neuroinflammation, through the reduction of IGF1R Sumoylation. KPT-330, as a potential alternative to physical exercise, enhances the neuroprotective role of IGF1R by inhibiting SUMOylation through targeting XPO1, presenting a promising therapeutic strategy for AD.

Uric acid-lowering therapy with benzbromarone in hypertension with asymptomatic hyperuricemia: a randomized study focusing left ventricular diastolic function.

BACKGROUND: Both hypertension and hyperuricemia are closely associated with the morbidity and mortality of heart failure with preserved ejection fraction (HFpEF). However, there is limited evidence on the effect of uric acid-lowering therapy on left ventricular (LV) diastolic function in this population. In this randomized study, we prescribed benzbromarone, a uric acid-lowering drug, to those with hypertension and asymptomatic hyperuricemia to investigate its clinical benefits by evaluating LV diastolic function, incidence of HFpEF and hospitalization for heart failure and cardiovascular death. METHODS: 230 participants were randomly assigned into two groups: uric acid-lowering group (benzbromarone) and control groups (without uric acid-lowering drug). The primary endpoint was LV diastolic function evaluated by echocardiography. The secondary endpoint of composite endpoints is the combination of new-onset HFpEF, hospitalization for heart failure and cardiovascular death. RESULTS: After a median of 23.5 months' follow-up (16-30 months), the primary endpoint reflected by E/e' in benzbromarone group reached a significant improvement when compared to control group (p <.001). Composite endpoints occurred in 11 patients of the control group while only 3 patients occurred in the benzbromarone group (p = .027). We also presented the favorable trend of freedom from the composite endpoints or new-onset HFpEF using Kaplan-Meier curve by log-rank test in benzbromarone group (p = .037 and p = .054). CONCLUSIONS: Our study demonstrated the efficiency of benzbromarone in hypertensive patients with concomitant asymptomatic hyperuricemia, including the benefits on ameliorating LV diastolic dysfunction as well as improving composite endpoints.

Fabrication of γ-Al2O3 Nanoarrays on Aluminum Foam Assisted by Hydroxide for Monolith Catalysts.

Heat distribution and good adhesion of the washcoat on monolith catalysts are critical to improving catalytic activity and long-term stability. Compared with cordierite, metal foam presents a high thermal conductivity coefficient. Also, the availability of "washcoat" in situ grown on metal substrates opens the door to eliminating the problem of coating peeling. Generally, hydrothermal or thermal methods are used for the fabrication of in situ grown washcoat on metal substrates. In this research, the aluminum foam monolith vertically aligned Al2O3 nanowire array is successfully prepared at ambient temperature in an alkaline solution for the first time. Furthermore, the Pt-loaded Al2O3 nanowire array (0.5 gPt/L monolith) is applied to C2H4 degradation. The catalyst converts 90% C2H4 at 147 °C with a gas hourly space velocity (GHSV) of 20,000 h-1. And a little decrease (1%) is observed in catalytic activity, even in 15 vol % water vapors. The catalysts show good thermal stability and water resistance property over 36 h at 300 °C. Above all, this study presents a simple way of in situ growth of washcoat on metal-substrate monolith with potentially scaled manufacturing. And the monolith catalyst shows good catalytic performance on C2H4, which can be applied for volatile organic compound treatment.

A Novel and Open Classification Emphasizing on Osteoligamentous Complex for Distal Clavicle Fractures.

OBJECTIVE: Current X-ray-based classification methods cannot describe all distal clavicle fracture (DCF) patterns, especially the osteoligamentous injury pattern of DCFs. We aimed to develop a novel classification based on the osteoligamentous injury pattern of the DCFs and investigated its reliability. METHODS: All DCFs from January 2017 to January 2022 were respectively screened and 45 cases (mean age 20-78; male 31, female 14) met the including criteria and were enrolled. Based on their Zanca view X-ray radiograph and three-dimensional CT construction images, we analyzed the osteoligamentous injury pattern of each case, particularly the acromioclavicular (AC) and coracoclavicular ligaments and their bone attachment. Then we developed a novel classification method, five types in total, sorting all DCFs according to their lesion manifestations of osteoligamentous complex. Also, we investigated the inter- and intra-observer reliability using kappa value. RESULTS: A novel classification method for DCF was developed, manifesting the avulsion or rupture of conoid and trapezoid ligaments, and involvement of AC joint. Forty-five cases of DCFs were included in this study. Among them, 11 (24.4%) were Type 1 fracture, three (6.7%) cases were Type 2, six cases (13.3%) were Type 3, 21 (46.7%) were Type 4, four (8.9%) were Type 5. Kappa values for inter-observer agreement were 0.57 after first evaluation and 0.61 after second evaluation. Intra-observer agreement was 0.72 for experienced shoulder specialist and 0.63 for radiologist. CONCLUSION: This new classification method is reliable to use, supplementary to current classification systems, and emphasizes on the osteoligamentous complex injury when opting for the treatment.

Canceling Notch Improves the Mechanical Safety of Clavicle Locking Plate: A 3D Finite Element Study.

OBJECTIVE: Implant failure is a disastrous complication of the operative treatment of midshaft clavicle fractures, and improving the osteosynthesis plate is a strategy for preventing this. We aimed to investigate whether canceling the notch and adding screw-hole inserts enhanced the mechanical properties of the plate. METHODS: A clavicle model was generated based on the CT images of six adult volunteers (age range, 20-40 years; three males and three females; height range 160-175) using dedicated software, and a midshaft fracture model was created. The domestically made seven-hole locking plate commonly used for midshaft clavicle fractures was simulated (Model I); modifications were made to the plate (Model II). Using 3D finite element analysis, we simulated the fracture construct under three different load conditions-downward cantilever bending, axial compression, and axial torsion-and compared the stress distribution. RESULTS: We found that under axial compression, Model II experienced its maximum stress on the plate at 551.9MPa, which was less than that in Model I (790.4 MPa). Moreover, a greater stress concentration at the fracture site was observed under axial torsion, despite the maximum stress of both the models being similar. CONCLUSION: Canceling the notch and filling the screw holes near the fracture can ameliorate stress concentration on the internal fixation construct and enhance its reliability under axial compression. This improvement has substantial effects on the mechanical properties of implants and potentially prevents implant failure. Modern osteosynthesis anatomical implants need to be improved.

Low-intensity pulsed ultrasound promotes skeletal muscle regeneration via modulating the inflammatory immune microenvironment.

Background: Low-intensity pulsed ultrasound (LIPUS, a form of mechanical stimulation) can promote skeletal muscle functional repair, but a lack of mechanistic understanding of its relationship and tissue regeneration limits progress in this field. We investigated the hypothesis that specific energy levels of LIPUS mediates skeletal muscle regeneration by modulating the inflammatory microenvironment. Methods: To address these gaps, LIPUS irritation was applied in vivo for 5 min at two different intensities (30mW/cm2 and 60mW/cm2) in next 7 consecutive days, and the treatment begun at 24h after air drop-induced contusion injury. In vitro experiments, LIPUS irritation was applied at three different intensities (30mW/cm2, 45mW/cm2, and 60mW/cm2) for 2 times 24h after introduction of LPS in RAW264.7. Then, we comprehensively assessed the functional and histological parameters of skeletal muscle injury in mice and the phenotype shifting in macrophages through molecular biological methods and immunofluorescence analysis both in vivo and in vitro. Results: We reported that LIPUS therapy at intensity of 60mW/cm2 exhibited the most significant differences in functional recovery of contusion-injured muscle in mice. The comprehensive functional tests and histological analysis in vivo indirectly and directly proved the effectiveness of LIPUS for muscle recovery. Through biological methods and immunofluorescence analysis both in vivo and in vitro, we found that this improvement was attributable in part to the clearance of M1 macrophages populations and the increase in M2 subtypes with the change of macrophage-mediated factors. Depletion of macrophages in vivo eliminated the therapeutic effects of LIPUS, indicating that improvement in muscle function was the result of M2-shifted macrophage polarization. Moreover, the M2-inducing effects of LIPUS were proved partially through the WNT pathway by upregulating FZD5 expression and enhancing ß-catenin nuclear translocation in macrophages both in vitro and in vivo. The inhibition and augment of WNT pathway in vitro further verified our results. Conclusion: LIPUS at intensity of 60mW/cm2 could significantly promoted skeletal muscle regeneration through shifting macrophage phenotype from M1 to M2. The ability of LIPUS to direct macrophage polarization may be a beneficial target in the clinical treatment of many injuries and inflammatory diseases.