Biocompatibility and safety evaluation of a silk fibroin-doped calcium polyphosphate scaffold copolymer in vitro and in vivo

For the reconstruction of cartilage and bone defects, bone repair scaffolds with porous network structures have been extensively studied. In our previous study, CPP-type bioceramics showed higher compressive strength and enhanced degradation after silk fibroin doping, and SF/CPP could be considered a suitable bioceramic for bone tissue-engineering. The aim of this study was to evaluate the biocompatibility and safety of SF/CPP in vitro and in vivo. The cell biocompatibility was evaluated with regard to the cytotoxicity of the scaffolds using co-culture and MTT tests in vitro. The in vivo biocompatibility of SF/CPP was evaluated by implanting the scaffolds in the subcutaneous and intramuscular regions of experimental animals. We established an experimental animal model to prepare critical-sized cranial defects and evaluated the biodegradability and osteoconductivity of the scaffolds in vivo. The results indicated that the SF/CPP scaffold yielded better biocompatibility and safety performance than the CPP scaffold in vitro and in vivo. Immunohistochemistry staining in vivo for OPN and OCN also indicated that SF/CPP has potential to promote the regeneration of critical-sized cranial defects. The SF/CPP scaffold has good biocompatibility and safety for experimental animals and could also serve as a potential effective bioceramic for a range of bone regeneration applications

Limited Regeneration Potential with Minimal Epicardial Progenitor Conversions in the Neonatal Mouse Heart after Injury

The regeneration capacity of neonatal mouse heart is controversial. In addition, whether epicardial cells provide a progenitor pool for de novo heart regeneration is incompletely defined. Following apical resection of the neonatal mouse heart, we observed limited regeneration potential. Fate-mapping of Tbx18MerCreMer mice revealed that newly formed coronary vessels and a limited number of cardiomyocytes were derived from the T-box transcription factor 18 (Tbx18) lineage. However, further lineage tracing with SM-MHCCreERT2 and Nfactc1Cre mice revealed that the new smooth muscle and endothelial cells are in fact derivatives of pre-existing coronary vessels. Our data show that neonatal mouse heart can regenerate but that its potential is limited. Moreover, although epicardial cells are multipotent during embryogenesis, their contribution to heart repair through "stem" or "progenitor" cell conversion is minimal after birth. These observations suggest that early embryonic heart development and postnatal heart regeneration are distinct biological processes. Multipotency of epicardial cells is significantly decreased after birth

Cardiac Sca-1+ cells are not intrinsic stem cells for myocardial development, renewal and repair

Background: For over a decade, Sca-1+ cells within the mouse heart have been widely recognized as a stem cell population with multipotency that can give rise to cardiomyocytes, endothelial cells and smooth muscle cells in vitro and after cardiac grafting. However, the developmental origin and authentic nature of these cells remain elusive. Methods: Here, we used a series of high-fidelity genetic mouse models to characterize the identity and regenerative potential of cardiac resident Sca-1+ cells. Results: With these novel genetic mouse models, we found that Sca-1 does not label cardiac precursor cells during early embryonic heart formation. Postnatal cardiac resident Sca-1+ cells are in fact a pure endothelial cell population. They retain endothelial properties and exhibit minimal cardiomyogenic potential during development, normal aging and upon ischemic injury. Conclusions: Our study provides definitive insights into the nature of cardiac resident Sca-1+ cells. The observations challenge the current dogma that cardiac resident Sca-1+ cells are intrinsic stem cells for myocardial development, renewal and repair and suggest that the mechanisms of transplanted Sca-1+ cells in heart repair need to be reassessed

The Role of Oxidative Stress in the Process of Osteogenic Differentiation of Human Vascular Smooth Muscle Cells in Vitro

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Epinephrine Enhances the Response of Macrophages under LPS Stimulation

Trauma associated with infection may directly trigger a neuroendocrine reaction in vivo while the hormone epinephrine is known to mediate immune responses to inflammation after injury. However, the role of epinephrine during the earliest stage of trauma still remains unclear. We therefore explored the role of epinephrine on activated macrophages under LPS stimulation in vitro as well as the mechanisms underlying its effect. Dose- and time-dependent effects of epinephrine on macrophage immune function were assessed after LPS activation. We also employed CD14 siRNA interference to investigate whether CD14 played a role in the mechanism underlying the effect of epinephrine on LPS-induced macrophage responses. Our results showed that epinephrine pretreatment (10 ng/mL) significantly promoted immune responses from LPS stimulated macrophages, including phagocytic rate, phagocytic index, TNFα/IL-1β/IL-10 secretion, and CD14 expression (P < 0.05). Moreover, TNFα/IL-1β/IL-10 levels attained their peak value 1 hour after incubation with 10 ng/mL epinephrine (P < 0.05), and CD14 siRNA transfection dramatically decreased phagocytosis and cytokine secretion by LPS-activated macrophages (P < 0.05). We therefore conclude that 10 ng/mL epinephrine enhances immune responses from macrophages under LPS stimulation and that the underlying mechanism may relate to CD14 upregulation on the surface of macrophages

Why would people purchase personalized products online?:an exploratory study

Abstract Product personalization, which allows customers to tailor products according to their own preference, has become increasingly important to many companies. Although prior studies have investigated service personalization (e.g., offer personalization and web personalization), few studies have comprehensively explored why people are willing to purchase personalized products online. This study uses a qualitative approach with 71 semi-structured interviews to explore the reasons. The data was analyzed using content analysis. The results reveal that people purchase personalized products online primarily due to the following reasons: uniqueness seeking, emotional attachment, identity expression, enjoyment, vanity, innovation, ownership, and perceived control. These factors are interpreted based on uniqueness theory and the theory of planned behavior. In addition, other factors (specifically trust, price, and recommendation) pertaining to the website also explain why customers choose a particular website instead of other websites to purchase personalized products. The theoretical contributions of this study are discussed, along with practical implications and future possible research directions

Establishment of a recombinase polymerase amplification detection method for Puccinia striiformis f. sp. tritici

Abstract Wheat stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) is an airborne disease that endangers wheat during its entire growth period. In this study, the Pst134EA_003354 uncharacterized protein (GenBank: XM_047941824.1) of Pst was used as the target sequence, and the primers PS-RPA-F and PS-RPA-R, as well as the probe PS-LF-probe, were designed for recombinase polymerase amplification (RPA) technology. Flow chromatography was combined with the process to establish an RPA detection method for Pst. This method successfully established visual detection within 10 min under a constant temperature of 39 °C, and the detection results were consistent with those of ordinary PCR analysis. However, it only had high specificity for Pst, and the detection limit was 10 fg/μL. In addition, this rapid method successfully detected Pst from wheat leaves during the field incubation period, indicating substantial benefits for applied use. In summary, the RPA detection method established in this study has the favourable characteristics of high efficiency, simple functionality, and rapid and universal practicability, providing a theoretical basis for the early detection and prevention of Pst