3-Dimensional Bioprinting of a Tendon Stem Cell-Derived Exosomes Loaded Scaffold to Bridge the Unrepairable Massive Rotator Cuff Tear.

BACKGROUND: Unrepairable massive rotator cuff tears (UMRCTs) are challenging to surgeons owing to the severely retracted rotator cuff musculotendinous tissues and extreme defects in the rotator cuff tendinous tissues. PURPOSE: To fabricate a tendon stem cell-derived exosomes loaded scaffold (TSC-Exos-S) and investigate its effects on cellular bioactivity in vitro and repair in a rabbit UMRCT model in vivo. STUDY DESIGN: Controlled laboratory study. METHODS: TSC-Exos-S was fabricated by loading TSC-Exos and type 1 collagen (COL-I) into a 3-dimensional bioprinted and polycaprolactone (PCL)-based scaffold. The proliferation, migration, and tenogenic differentiation activities of rabbit bone marrow stem cells (BMSCs) were evaluated in vitro by culturing them in saline, PCL-based scaffold (S), COL-I loaded scaffold (COL-I-S), and TSC-Exos-S. In vivo studies were conducted on a rabbit UMRCT model, where bridging was repaired with S, COL-I-S, TSC-Exos-S, and autologous fascia lata (FL). Histological and biomechanical analyses were performed at 8 and 16 weeks postoperatively. RESULTS: TSC-Exos-S exhibited reliable mechanical strength and subcutaneous degradation, which did not occur before tissue regeneration. TSC-Exos-S significantly promoted the proliferation, migration, and tenogenic differentiation of rabbit BMSCs in vitro. In vivo studies showed that UMRCT repaired with TSC-Exos-S exhibited significant signs of tendinous tissue regeneration at the bridging site with regard to specific collagen staining. Moreover, no significant differences were observed in the histological and biomechanical properties compared with those repaired with autologous FL. CONCLUSION: TSC-Exos-S achieved tendinous tissue regeneration in UMRCT by providing mechanical support and promoting the trend toward tenogenic differentiation. CLINICAL RELEVANCE: The present study proposes a potential strategy for repairing UMRCT with severely retracted musculotendinous tissues and large tendinous tissue defects.

Multimaterial Printing of Serpentine Microarchitectures with Synergistic Mechanical/Piezoelectric Stimulation for Enhanced Cardiac-Specific Functional Regeneration.

Recreating the natural heart's mechanical and electrical environment is crucial for engineering functional cardiac tissue and repairing infarcted myocardium in vivo. In this study, multimaterial-printed serpentine microarchitectures are presented with synergistic mechanical/piezoelectric stimulation, incorporating polycaprolactone (PCL) microfibers for mechanical support, polyvinylidene fluoride (PVDF) microfibers for piezoelectric stimulation, and magnetic PCL/Fe3O4 for controlled deformation via an external magnet. Rat cardiomyocytes in piezoelectric constructs, subjected to dynamic mechanical stimulation, exhibit advanced maturation, featuring superior sarcomeric structures, improved calcium transients, and upregulated maturation genes compared to non-piezoelectric constructs. Furthermore, these engineered piezoelectric cardiac constructs demonstrate significant structural and functional repair of infarcted myocardium, as evidenced by enhanced ejection and shortening fraction, reduced fibrosis and inflammation, and increased angiogenesis. The findings underscore the therapeutic potential of piezoelectric cardiac constructs for myocardial infarction therapy.

Controlling the nutritional status score: a new tool for predicting postoperative mortality in patients with infrarenal abdominal aortic aneurysm treated with endovascular aneurysm repair.

Background: AAA is a fatal condition that commonly occurs during vascular surgery. Nutritional status exerts a significant influence on the prognosis of various pathological conditions Scores from the CONUT screening tool have been shown to predict outcomes of certain malignancies and chronic diseases. However, the ramifications of nutritional status on AAA patients undergoing EVAR have not been elucidated in prior studies. In this study, we aimed to elucidate the correlation between CONUT scores and postoperative prognostic outcomes in patients with AAA undergoing EVAR. Methods: This was a retrospective review of 177 AAA patients treated with EVAR from June 2018 to November 2019 in a single center. Patient characteristics, CONUT scores, and postoperative status were collected. These patients were stratified into groups A and B according to CONUT scores. Subsequently, a comparative analysis of the baseline characteristics between the two cohorts was conducted. Cox proportional hazards and logistic regression analyses were employed to identify the autonomous predictors of mid-term mortality and complications, respectively. Results: Compared with group A, patients in group B had higher midterm mortality (p < 0.001). Univariate analysis showed that CONUT scores; respiratory diseases; stent types; preoperative Hb, CRP, PT, and Fb levels were risk factors for death. Multivariate analysis confirmed that CONUT score [HR, 1.276; 95% CI, 1.029-1.584; p = 0.027] was an independent risk factor for mortality. Logistic regression analysis showed that prior arterial disease, smoking, and D-dimer levels were risk factors, although multivariate analysis showed smoking (OR, 3.492; 95% CI, 1.426-8.553; p = 0.006) was an independent risk factor. Kaplan-Meier curves showed that patients in group B had shorter mid-term survival than those in group A (log-rank p < 0.001). Conclusion: Malnutrition was strongly associated with mid-term mortality in patients with infrarenal AAA treated with EVAR.

MALDI-mass spectrometry imaging as a new technique for detecting non-heme iron in peripheral tissues via caudal vein injection of deferoxamine.

As one of the most common iron-chelating agents, deferoxamine (DFO) rapidly chelates iron in the body. Moreover, it does not compete for the iron characteristic of hemoglobin in the blood cells, which is common in the clinical treatment of iron poisoning. Iron is a trace element necessary to maintain organism normal life activities. Iron deficiency can lead to anemia, whereas iron overload can cause elevated levels of cellular oxidative stress and cell damage. As a consequence, detection of the iron content in tissues and blood is of great significance. The traditional techniques for detecting the iron content include inductively coupled plasma-mass spectrometry and atomic absorption spectrometry, which cannot be used for imaging purposes. Laser ablation-ICP-MS and synchrotron radiation micro-X-ray fluorescence can map the concentration and distribution of iron in tissues. However, these methods can only be used to measure the total iron levels in blood or tissues. In recent years, due to the deepening understanding of iron metabolism, diseases related to iron overload have attracted increasing attention. Therefore, we took advantage of the properties of DFO in terms of chelating iron and investigated different sampling times following DFO injection in the tail vein of mice. We used mass spectrometry imaging (MSI) technology to detect the DFO and ferrioxamine content in the blood and different tissues to indirectly characterize the non-heme iron content.

Genotoxicity and safety pharmacology of the rVSVInd(GML)-mspSGtc vaccine against SARS-CoV-2 in Sprague-Dawley rats and Beagle dogs.

The emergence of coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to a pandemic, prompting rapid vaccine development. Although vaccines are effective, the occurrence of rare adverse events following vaccination highlights the necessity of determining whether the benefits outweigh the risks posed by the infection itself. The recombinant Vesicular Stomatitis Virus (rVSV) platform is a promising vector for vaccines against emerging viruses. However, limited studies have evaluated the genotoxicity and safety pharmacology of this viral vector vaccine, which is crucial to ensure the safety of vaccines developed using this platform. Hence, the present study aimed to assess the genotoxicity and safety pharmacology of the rVSVInd(GML)-mspSGtc COVID-19 vaccine using micronucleus and comet assays, as well as neurobehavioral, body temperature, respiratory, and cardiovascular assessments in Sprague-Dawley rats and beagle dogs. The intramuscular administration of rVSVInd(GML)-mspSGtc at doses up to 1.5 × 109 PFU/animal did not increase the number of bone marrow micronucleated polychromatic erythrocytes or cause liver DNA damage. Additionally, it had no significant impact on neurobehavioral functions in rats and showed marginal temporary changes in body temperature, respiratory rate, heart rate, and electrocardiogram parameters in rats and dogs, all of which resolved within 24 h. Overall, following genotoxicity and pharmacological safety assessments, rVSVInd(GML)-mspSGtc displayed no notable systemic adverse effects in rats and dogs, suggesting its potential as a vaccine candidate for human clinical trials.

Janus Membranes Patch Achieves High-Quality Tendon Repair: Inhibiting Exogenous Healing and Promoting Endogenous Healing.

The imbalance between endogenous and exogenous healing is the fundamental reason for the poor tendon healing. In this study, a Janus patch was developed to promote endogenous healing and inhibit exogenous healing, leading to improved tendon repair. The upper layer of the patch is a poly(dl-lactide-co-glycolide)/polycaprolactone (PLGA/PCL) nanomembrane (PMCP-NM) modified with poly(2-methylacryloxyethyl phosphocholine) (PMPC), which created a lubricated and antifouling surface, preventing cell invasion and mechanical activation. The lower layer is a PLGA/PCL fiber membrane loaded with fibrin (Fb) (Fb-NM), serving as a temporary chemotactic scaffold to regulate the regenerative microenvironment. In vitro, the Janus patch effectively reduced 92.41% cell adhesion and 79.89% motion friction. In vivo, the patch inhibited tendon adhesion through the TGF-ß/Smad signaling pathway and promoted tendon maturation. This Janus patch is expected to provide a practical basis and theoretical guidance for high-quality soft tissue repair.

Healthy Tendon Stem Cell-Derived Exosomes Promote Tendon-To-Bone Healing of Aged Chronic Rotator Cuff Tears by Breaking the Positive-Feedback Cross-Talk between Senescent Tendon Stem Cells and Macrophages through the Modulation of Macrophage Polarization.

The re-tear rate of rotator cuff tears (RCT) after surgical repair is high, especially in aged patients with chronic tears. Senescent tendon stem cells (s-TSCs) generally exist in aged and chronically torn rotator cuff tendons and are closely associated with impaired tendon-to-bone healing results. The present study found a positive feedback cross-talk between s-TSCs and macrophages. The conditioned medium (CM) from s-STCs can promote macrophage polarization mainly toward the M1 phenotype, whose CM reciprocally accelerated further s-TSC senescence. Additional healthy tendon stem-cells derived exosomes (h-TSC-Exos) can break this positive feedback cross-talk by skewing macrophage polarization from the M1 phenotype to the M2 phenotype, attenuating s-TSCs senescence. S-TSC senescence acceleration or attenuation effects induced by M1 or M2 macrophages are associated with the inhibition or activation of the bone morphogenetic protein 4 signaling pathway following RNA sequencing analysis. Using an aged-chronic rotator cuff tear rat model, it is found that h-TSC-Exos can shift the microenvironment in the tendon-to-bone interface from a pro-inflammatory to an anti-inflammatory type at the acute postoperative stage and improve the tendon-to-bone healing results, which are associated with the rejuvenated s-TSCs. Therefore, this study proposed a potential strategy to improve the healing of aged chronic RCT.

Short-Chain Sulfur Confined into Nitrogen-Doped Hollow Carbon Nanospheres for High-Capacity Potassium Storage.

Carbon-based materials are one of the ideal negative electrode materials for potassium ion batteries. However, the limited active sites and sluggish diffusion ion kinetics still hinder its commercialization process. To address these problems, we design a novel carbon composite anode, by confining highly reactive short-chain sulfur molecules into nitrogen-doped hollow carbon nanospheres (termed SHC-450). The formation process involves the controlled synthesis of hollow polyaniline (PANI) nanospheres as precursors via an Ostwald ripening mechanism and subsequent sulfuration treatment. The high content of constrained short-chain sulfur molecules (20.94 wt%) and considerable N (7.15 wt%) ensure sufficient active sites for K+ storage in SHC-450. Accordingly, the SHC-450 electrode exhibits a high reversible capacity of 472.05 mAh g-1 at 0.1 A g-1 and good rate capability (172 mAh g-1 at 2 A g-1). Thermogravimetric analysis shows that SHC-450 has impressive thermal stability to withstand a high temperature of up to 640 °C. Ex situ spectroscopic characterizations reveal that the short-chain sulfur provides high capacity through reversible formation of K2S. Moreover, its special hollow structure not only provides ample space for highly active short-chain sulfur reactants but also effectively mitigates volume expansion during the sulfur conversion process. This work offers new perspectives on enhanced K+ storage performance from an interesting anode design and the space-limited domain principle.

Detection and coverage estimation of purple nutsedge in turf with image classification neural networks.

BACKGROUND: Accurate detection of weeds and estimation of their coverage is crucial for implementing precision herbicide applications. Deep learning (DL) techniques are typically used for weed detection and coverage estimation by analyzing information at the pixel or individual plant level, which requires a substantial amount of annotated data for training. This study aims to evaluate the effectiveness of using image-classification neural networks (NNs) for detecting and estimating weed coverage in bermudagrass turf. RESULTS: Weed-detection NNs, including DenseNet, GoogLeNet and ResNet, exhibited high overall accuracy and F1 scores (≥0.971) throughout the k-fold cross-validation. DenseNet outperformed GoogLeNet and ResNet with the highest overall accuracy and F1 scores (0.977). Among the evaluated NNs, DenseNet showed the highest overall accuracy and F1 scores (0.996) in the validation and testing data sets for estimating weed coverage. The inference speed of ResNet was similar to that of GoogLeNet but noticeably faster than DenseNet. ResNet was the most efficient and accurate deep convolution neural network for weed detection and coverage estimation. CONCLUSION: These results demonstrated that the developed NNs could effectively detect weeds and estimate their coverage in bermudagrass turf, allowing calculation of the herbicide requirements for variable-rate herbicide applications. The proposed method can be employed in a machine vision-based autonomous site-specific spraying system of smart sprayers. © 2024 Society of Chemical Industry.

Evaluating the toxicity of the roots of Asarum heterotropoides var. mandshuricum extracted using the decoction method: Genotoxicity, single-dose toxicity, and 13-week repeated-dose toxicity studies.

ETHNOPHARMACOLOGICAL RELEVANCE: The roots of Asarum heterotropoides F. Maekawa var. mandshuricum F. Maekawa (AR) is a traditional herbal medicine used across Asia, including Korea, China, and Japan. AR exhibits a range of biological activities, such as anti-inflammatory, anti-cancer, cold treatment, and anti-nociceptive effects. Various extraction methods, including decoction, which utilizes traditional knowledge and techniques. The AR decoction extract expected to contain fewer toxicants and have reduced toxicity due to the use of hot water in the extraction process. However, scientific evidence on the toxicity of AR decoction extracts is lacking, necessitating further studies for safe usage. AIM OF THE STUDY: This study aimed to evaluate the genotoxicity and toxicity of single and repeated administration of AR decoction extracts. MATERIALS AND METHODS: The genotoxicity was assessed using a bacterial reverse mutation (Ames test), an in vitro mammalian chromosome aberration test (CA test), and an in vivo micronucleus test (MN test) in Sprague-Dawley (SD) rats. The general toxicity was evaluated through single-dose and 13-week repeated-dose toxicity studies. In the single-dose toxicity study, 40 SD rats were orally administered AR decoction extract at doses of 1000, 2000, and 5000 mg/kg. In the 13-week repeated-dose toxicity study, 140 SD rats received daily oral doses of 0, 250, 500, 1000, 2000, and 5000 mg/kg of AR decoction extract. RESULTS: The genotoxicity tests revealed that AR decoction extract was not genotoxic. The single-dose toxicity study showed no changes in body weight, clinical pathology, or macroscopic findings, with the approximate lethal dose (ALD) exceeding 5000 mg/kg. The 13-week repeated-dose toxicity study demonstrated no treatment-related changes in body weight, general symptoms, hematology, clinical chemistry, or urinalysis. Histopathological findings revealed hyperplasia of squamous cells in the forestomach after AR decoction extract administration, a treatment-related effect that resolved during the recovery period. The no observed adverse effect level (NOAEL) for both male and female rats was estimated to be 2000 mg/kg. CONCLUSIONS: This study establishes the non-toxic dose of AR decoction extract, providing a foundation for further non-clinical and clinical evaluations AR safety.

Heart-on-a-chip systems with tissue-specific functionalities for physiological, pathological, and pharmacological studies.

Recent advances in heart-on-a-chip systems hold great promise to facilitate cardiac physiological, pathological, and pharmacological studies. This review focuses on the development of heart-on-a-chip systems with tissue-specific functionalities. For one thing, the strategies for developing cardiac microtissues on heart-on-a-chip systems that closely mimic the structures and behaviors of the native heart are analyzed, including the imitation of cardiac structural and functional characteristics. For another, the development of techniques for real-time monitoring of biophysical and biochemical signals from cardiac microtissues on heart-on-a-chip systems is introduced, incorporating cardiac electrophysiological signals, contractile activity, and biomarkers. Furthermore, the applications of heart-on-a-chip systems in intelligent cardiac studies are discussed regarding physiological/pathological research and pharmacological assessment. Finally, the future development of heart-on-a-chip toward a higher level of systematization, integration, and maturation is proposed.

Micro-nano hierarchical scaffold providing temporal-matched biological constraints for tendon reconstruction.

Due to the limitations of tendon biology, high-quality tendon repair remains a clinical and scientific challenge. Here, a micro-nano hierarchical scaffold is developed to promote orderly tendon regeneration by providing temporal-matched biological constraints. In short, fibrin (Fb), which provides biological constraints, is loaded into poly (DL-lactide-co-glycolide) nanoyarns with suitable degradation cycles (Fb-loaded nanofiber yarns (Fb-NY)). Then further combined with braiding technology, temporary chemotactic Fb scaffolds with tendon extracellular matrix-like structures are obtained to initiate the regeneration process. At the early stage of healing (2 w), the regeneration microenvironment is regulated (inducing M2 macrophages and restoring the early blood supply necessary for healing) by Fb, and the alignment of cells and collagen is induced by nanoyarn. At the late healing stage (8 w), with the degradation of Fb-NY, non-functional vascular regression occurs, and the newborn tissues gradually undergo load-bearing remodeling, restoring the anvascularous and ordered structure of the tendon. In summary, the proposed repair strategy provides temporal-matched biological constraints, offering a potential pathway to reconstruct the ordered structure and function of tendons.

Prognostic Significance of Programmed Cell Death Ligand 1 Expression in High-Grade Serous Ovarian Carcinoma: A Systematic Review and Meta-Analysis.

(1) Background: High-grade serous ovarian carcinoma (HGSOC) is an aggressive subtype of ovarian cancer. Recent advances have introduced prognostic markers and targeted therapies. Programmed cell death ligand 1 (PD-L1) has emerged as a potential biomarker for HGSOC, with implications for prognosis and targeted therapy eligibility; (2) Methods: A literature search was conducted on major databases, and extracted data were categorized and pooled. Subgroup analysis was performed for studies with high heterogeneity. (3) Results: Data from 18 eligible studies were categorized and pooled based on PD-L1 scoring methods, survival analysis types, and endpoints. The result showed an association between high PD-L1 expression and a favorable prognosis in progression-free survival (HR = 0.53, 95% CI = 0.35-0.78, p = 0.0015). Subgroup analyses showed similar associations in subgroups of neoadjuvant chemotherapy patients (HR = 0.6, 95% CI = 0.4-0.88, p = 0.009) and European studies (HR = 0.59, 95% CI = 0.42-0.82, p = 0.0017). In addition, subgroup analyses using data from studies using FDA-approved PD-L1 antibodies suggested a significant association between favorable prognosis and high PD-L1 expression in a subgroup including high and low stage data in overall survival data (HR = 0.46, 95% CI = 0.3-0.73, p = 0.0009). (4) Conclusions: This meta-analysis revealed a potential association between high PD-L1 expression and favorable prognosis. However, caution is warranted due to several limitations. Validation via large-scale studies, with mRNA analysis, whole tissue sections, and assessments using FDA-approved antibodies is needed.

Nonclinical safety assessment and immunogenicity of rVSVInd(GML)-mspSGtc vaccine for SARS-CoV-2 in rabbits.

The worldwide health, economic, and societal consequences of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic have been devastating. The primary strategy to prevent new infectious diseases is to vaccinate the majority of people worldwide. However, the significant hurdles that are faced include vaccine safety concerns and vaccine reluctance. Among the various types of vaccines, the recombinant vesicular stomatitis virus (rVSV) is a promising candidate owing to its safety and efficacy. Therefore, we investigated the toxicity, immunogenicity, and local tolerance of the rVSVInd(GML)-mspSGtc vaccine against SARS-CoV-2. New Zealand White (NZW) rabbits were administered single or three repeated intramuscular injections of rVSVInd(GML)-mspSGtc every 2 weeks, followed by a 4-week recovery period. Male and female rabbits were randomly assigned into three groups: a control group and two dose-level groups (1 × 109 and 4 × 109 PFU/mL). Treatment-related changes included a temporary increase in body temperature and local inflammation at the injection site. These findings indicated recovery or a trend toward recovery, with no overt systemic toxicity. Immunogenicity analysis results suggested that rVSVInd(GML)-mspSGtc elicited a robust dose-dependent immune response in terms of neutralizing antibodies and IgG antibodies against the SARS-CoV-2 spike protein. In addition, the immune response intensity was increased by repeated vaccine administration. In conclusion, both the approximate lethal dose and the no observed adverse effect level for rVSVInd(GML)-mspSGtc exceeded 4 × 109 PFU/mL in NZW rabbits. Overall, rVSVInd(GML)-mspSGtc induced no adverse effects at the maximum dosage tested; however, its efficacy warrants further clinical evaluation.

Increased SIRT3 combined with PARP inhibition rescues motor function of SBMA mice.

Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disease with substantial mitochondrial and metabolic dysfunctions. SBMA is caused by polyglutamine (polyQ) expansion in the androgen receptor (AR). Activating or increasing the NAD+-dependent deacetylase, SIRT3, reduced oxidative stress and death of cells modeling SBMA. However, increasing diminished SIRT3 in AR100Q mice failed to reduce acetylation of the SIRT3 target/antioxidant, SOD2, and had no effect on increased total acetylated peptides in quadriceps. Yet, overexpressing SIRT3 resulted in a trend of motor recovery, and corrected TCA cycle activity by decreasing acetylation of SIRT3 target proteins. We sought to boost blunted SIRT3 activity by replenishing diminished NAD+ with PARP inhibition. Although NAD+ was not affected, overexpressing SIRT3 with PARP inhibition fully restored hexokinase activity, correcting the glycolytic pathway in AR100Q quadriceps, and rescued motor endurance of SBMA mice. These data demonstrate that targeting metabolic anomalies can restore motor function downstream of polyQ-expanded AR.

Enhancement of Tendon-to-Bone Healing: Choose a Monophasic or Hierarchical Scaffold?

BACKGROUND: To enhance the healing of tendon to bone, various biomimetically hierarchical scaffolds have been proposed. However, the fabrication of such scaffolds is complicated. Furthermore, the most significant result after a routine repair is loss of the transition zone between the tendon and bone, whose main components are similar to fibrocartilage. PURPOSE: To compare tendon-to-bone healing results in a rabbit model using a monophasic graft (decellularized fibrocartilage graft; DFCG) and hierarchical graft (decellularized tendon-to-bone complex; DTBC) that contain the native hierarchical enthesis. STUDY DESIGN: Controlled laboratory study. METHODS: DFCG and DTBC were harvested from allogenic rabbits. A rabbit model of a chronic rotator cuff tear was established, and 3 groups were assessed: direct repair or repair with DFCG or DTBC fixed between the tendon and bone. Hierarchical evaluations of the repaired tendon-to-bone interface were performed with regard to the tendon zone, transition zone, and bone zone using histological staining and micro-computed tomography scanning. Biomechanical analysis was performed to evaluate the general healing strength. RESULTS: The healing results in the tendon zone exhibited no significant difference among the 3 groups at any time point. In the transition zone, the grade in the direct repair group was significantly lower than that in the DFCG and DTBC groups at 4 weeks, and the grade in the DFCG group was significantly lower than that in the DTBC group at this time point. However, any significant difference between the DFCG group and DTBC group could no longer be detected at 8 and 16 weeks, which was inconsistent with the results of the biomechanical analysis. Micro-computed tomography analysis showed no significant difference among the 3 groups with regard to bone mineral density at 16 weeks. CONCLUSION: A monophasic DFCG was able to achieve enhanced tendon-to-bone healing similar to that with hierarchical DTBC over the long term, with regard to both histological and biomechanical properties. CLINICAL RELEVANCE: Fabrication of a monophasic scaffold instead of a hierarchical scaffold to promote regeneration and remodeling of a transition zone, which was mainly composed of fibrocartilaginous matrix between the tendon and bone, may be sufficient to enhance tendon-to-bone healing.

Preclinical evaluation of general toxicity and safety pharmacology of a receptor-binding domain-based COVID-19 subunit vaccine in various animal models.

The coronavirus disease 2019 pandemic has resulted in the introduction of several naïve methods of vaccine development, which have been used to prepare novel viral vectors and mRNA-based vaccines. However, reluctance to receive vaccines owing to the uncertainty regarding their safety is prevalent. Therefore, rigorous safety evaluation of vaccines through preclinical toxicity studies is critical to determine the safety profiles of vaccine candidates. This study aimed to evaluate the toxicity profile of HuVac-19, a subunit vaccine of SARS-CoV-2 utilizing the receptor-binding domain as an antigen, in rats, rabbits, and dogs using single- and repeat-dose study designs. Repeat-dose toxicity studies in rats and rabbits showed transient changes in hematological and serum biochemical parameters in the adjuvant and/or vaccine groups; however, these changes were reversed or potentially reversible after the recovery period. Moreover, temporary reversible changes in absolute and relative organ weights were observed in the prostate of rats and the thymus of rabbits. Gross examination of the injection sites in rats and rabbits treated with the adjuvant- and HuVac-19 showed discoloration and foci, whereas histopathological examination showed granulomatous inflammation, inflammatory cell infiltration, and myofiber degeneration/necrosis. This inflammatory response was local, unassociated with other toxicological changes, and resolved. In a pharmacological safety study, no toxicological or physiological changes associated with HuVac-19 administration were observed. In conclusion, HuVac-19 was not associated with any major systemic adverse effects in the general toxicity and safety pharmacology evaluation, demonstrating that HuVac-19 is a vaccine candidate with sufficient capacity to be used in human clinical trials.

Three-Dimensional Bioprinting of a Structure-, Composition-, and Mechanics-Graded Biomimetic Scaffold Coated with Specific Decellularized Extracellular Matrix to Improve the Tendon-to-Bone Healing.

Healing of a damaged tendon-to-bone enthesis occurs through the formation of fibrovascular scar tissue with greatly compromised histological and biomechanical properties instead of the regeneration of a new enthesis due to the lack of graded tissue-engineering zones in the interface during the healing process. In the present study, a structure-, composition-, and mechanics-graded biomimetic scaffold (GBS) coated with specific decellularized extracellular matrix (dECM) (GBS-E) aimed to enhance its cellular differentiation inducibilities was fabricated using a three-dimensional (3-D) bioprinting technique. In vitro cellular differentiation studies showed that from the tendon-engineering zone to the bone-engineering zone in the GBS, the tenogenic differentiation inducibility decreased in correspondence with an increase in the osteogenic differentiation inducibility. The chondrogenic differentiation inducibility peaked in the middle, which was in consistent with the graded cellular phenotypes observed in a native tendon-to-bone enthesis, while specific dECM coating from the tendon-engineering zone to the bone-engineering zone (tendon-, cartilage-, and bone-derived dECM, respectively) further enhanced its cellular differentiation inducibilities (GBS-E). In a rabbit rotator cuff tear model, histological analysis showed that the GBS-E group exhibited well-graded tendon-to-bone differentiated properties in the repaired interface that was similar to a native tendon-to-bone enthesis at 16 weeks. Moreover, the biomechanical properties in the GBS-E group were also significantly higher than those in other groups at 16 weeks. Therefore, our findings suggested a promising tissue-engineering strategy for the regeneration of a complex enthesis using a three-dimensional bioprinting technique.

A malignant proliferating trichilemmal cyst arising on the elbow of a man: A case report and review of the literature.

INTRODUCTION: Trichilemmal cysts (TCs) are common benign cysts that form from the hair follicles in the skin. Proliferating trichilemmal cysts (PTCs) are rare types of TCs characterized by rapid cellular proliferation. Malignant transformation of PTC (MPTC) is a rare adnexal tumor that account for <0.1% of all skin cancers. TCs and PTCs are benign tumors; however, MPTCs grow rapidly and are prone to metastasis. CASE PRESENTATION: A 77-year-old man was referred to our hospital with a solitary pinkish mass on his left elbow. Trichilemmal carcinoma arising from a PTC was confirmed through excisional biopsy, and wide excision was performed. One month postoperatively, a cystic mass was observed and was suspected to have local recurrence; however, bursitis was confirmed after excisional biopsy. After 1 year of follow-up, the patient maintained an improvement without recurrence or any other surgical complications. CONCLUSIONS: In addition to being a very rare disease, MTPC occurred in the elbow of a man who does not fit the general etiology; therefore, it is considered an interesting case, and we report this case for academic contribution.