Multiscale embedded printing of engineered human tissue and organ equivalents.

Creating tissue and organ equivalents with intricate architectures and multiscale functional feature sizes is the first step toward the reconstruction of transplantable human tissues and organs. Existing embedded ink writing approaches are limited by achievable feature sizes ranging from hundreds of microns to tens of millimeters, which hinders their ability to accurately duplicate structures found in various human tissues and organs. In this study, a multiscale embedded printing (MSEP) strategy is developed, in which a stimuli-responsive yield-stress fluid is applied to facilitate the printing process. A dynamic layer height control method is developed to print the cornea with a smooth surface on the order of microns, which can effectively overcome the layered morphology in conventional extrusion-based three-dimensional bioprinting methods. Since the support bath is sensitive to temperature change, it can be easily removed after printing by tuning the ambient temperature, which facilitates the fabrication of human eyeballs with optic nerves and aortic heart valves with overhanging leaflets on the order of a few millimeters. The thermosensitivity of the support bath also enables the reconstruction of the full-scale human heart on the order of tens of centimeters by on-demand adding support bath materials during printing. The proposed MSEP demonstrates broader printable functional feature sizes ranging from microns to centimeters, providing a viable and reliable technical solution for tissue and organ printing in the future.

Molecular mechanisms of leukocyte ß2 integrin activation.

Integrins are transmembrane receptors that mediate cell-cell and cell-extracellular matrix adhesion. Although all integrins can undergo activation (affinity change for ligands), the degree of activation is most spectacular for integrins on blood cells. The ß2 integrins are exclusively expressed on the surface of all leukocytes including neutrophils, lymphocytes, and monocytes. They are essential for many leukocyte functions and are strictly required for neutrophil arrest from rolling. The inside-out integrin activation process receives input from chemokine receptors and adhesion molecules. The integrin activation pathway involves many cytoplasmic signaling molecules such as spleen tyrosine kinase, other kinases like Bruton's tyrosine kinase, phosphoinositide 3-kinases, phospholipases, Rap1 GTPases, and the Rap1-GTP-interacting adapter molecule. These signaling events ultimately converge on talin-1 and kindlin-3, which bind to the integrin ß cytoplasmic domain and induce integrin conformational changes: extension and high affinity for ligand. Here, we review recent structural and functional insights into how talin-1 and kindlin-3 enable integrin activation, with a focus on the distal signaling components that trigger ß2 integrin conformational changes and leukocyte adhesion under flow.

Bone Marrow Transplantation Rescues Monocyte Recruitment Defect and Improves Cystic Fibrosis in Mice.

Cystic fibrosis (CF) is an inherited life-threatening disease accompanied by repeated lung infections and multiorgan inflammation that affects tens of thousands of people worldwide. The causative gene, cystic fibrosis transmembrane conductance regulator (CFTR), is mutated in CF patients. CFTR functions in epithelial cells have traditionally been thought to cause the disease symptoms. Recent work has shown an additional defect: monocytes from CF patients show a deficiency in integrin activation and adhesion. Because monocytes play critical roles in controlling infections, defective monocyte function may contribute to CF progression. In this study, we demonstrate that monocytes from CFTRΔF508 mice (CF mice) show defective adhesion under flow. Transplanting CF mice with wild-type (WT) bone marrow after sublethal irradiation replaced most (60-80%) CF monocytes with WT monocytes, significantly improved survival, and reduced inflammation. WT/CF mixed bone marrow chimeras directly demonstrated defective CF monocyte recruitment to the bronchoalveolar lavage and the intestinal lamina propria in vivo. WT mice reconstituted with CF bone marrow also show lethality, suggesting that the CF defect in monocytes is not only necessary but also sufficient to cause disease. We also show that monocyte-specific knockout of CFTR retards weight gains and exacerbates dextran sulfate sodium-induced colitis. Our findings show that providing WT monocytes by bone marrow transfer rescues mortality in CF mice, suggesting that similar approaches may mitigate disease in CF patients.

Kindlin-3 recruitment to the plasma membrane precedes high-affinity ß2-integrin and neutrophil arrest from rolling.

Integrin-mediated neutrophil adhesion starts by arrest from rolling. Activation of integrins involves conformational changes from an inactive, bent conformation to an extended conformation (E+) with high affinity for ligand binding (H+). The cytoplasmic protein kindlin-3 is necessary for leukocyte adhesion; mutations of kindlin-3 cause leukocyte adhesion deficiency type 3. Kindlin-3 binds the ß2-integrin cytoplasmic tail at a site distinct from talin-1, but the molecular mechanism by which kindlin-3 activates ß2-integrins is unknown. In this study, we measured the spatiotemporal dynamics of kindlin-3 and ß2-integrin conformation changes during neutrophil and HL-60 cell rolling and arrest under flow. Using high-resolution quantitative dynamic footprinting microscopy and kindlin-3-fluorescent protein (FP) fusion proteins, we found that kindlin-3 was recruited to the plasma membrane in response to interleukin-8 (IL-8) before induction of the H+ ß2-integrin conformation. Intravital imaging revealed that EGFP-kindlin-3-reconstituted, kindlin-3-knockout neutrophils arrest in vivo in response to CXCL1. EGFP-kindlin-3 in primary mouse neutrophils was also recruited to the plasma membrane before arrest. Upon arrest, we found small clusters of high-affinity ß2-integrin molecules within large areas of membrane-proximal kindlin-3 FP. Deletion of kindlin-3 or its pleckstrin homology (PH) domain in neutrophil-like HL-60 cells completely abolished H+ ß2-integrin induction. IL-8 also triggered recruitment of the isolated kindlin-3 PH domain to the plasma membrane before arrest. In summary, we showed that the kindlin-3 PH domain is necessary for recruitment to the plasma membrane, where full-length kindlin-3 is indispensable for the induction of high-affinity ß2-integrin.

Imaging of the immune system - towards a subcellular and molecular understanding.

Immune responses involve many types of leukocytes that traffic to the site of injury, recognize the insult and respond appropriately. Imaging of the immune system involves a set of methods and analytical tools that are used to visualize immune responses at the cellular and molecular level as they occur in real time. We will review recent and emerging technological advances in optical imaging, and their application to understanding the molecular and cellular responses of neutrophils, macrophages and lymphocytes. Optical live-cell imaging provides deep mechanistic insights at the molecular, cellular, tissue and organism levels. Live-cell imaging can capture quantitative information in real time at subcellular resolution with minimal phototoxicity and repeatedly in the same living cells or in accessible tissues of the living organism. Advanced FRET probes allow tracking signaling events in live cells. Light-sheet microscopy allows for deeper tissue penetration in optically clear samples, enriching our understanding of the higher-level organization of the immune response. Super-resolution microscopy offers insights into compartmentalized signaling at a resolution beyond the diffraction limit, approaching single-molecule resolution. This Review provides a current perspective on live-cell imaging in vitro and in vivo with a focus on the assessment of the immune system.

Hepatic portal venous gas: A case report and analysis of 131 patients using PUBMED and MEDLINE database.

OBJECTIVE: Hepatic portal pneumatosis has a high mortality rate, and whether surgical intervention is necessary remains controversial. This experiment retrospectively analyzed the etiology, treatment methods and prognosis of adult patients with hepatoportal pneumocele to provide a theoretical basis for the treatment of this disease. METHODS: We analyzed the clinical symptoms and post-treatment of a 43-year-old male patient with HPVG admitted to hospital. We retrieved adult non-iatrogenic HPVG cases with complete clinical data in PUBMED,  and MEDLINE and other databases were retrieved for analysis, and summarized the pathogenesis, clinical symptoms, pathogenesis, pathogenesis and prognosis of different treatment schemes were summarized. RESULTS: The main etiology of HPVG are intestinal ischemia (27%), severe enteritis/intestinal perforation/intestinal fistula (16%), intestinal obstruction (7%), abdominal infection (7%), gastric diseases (11%), appendicitis and its complications (5%), acute hemorrhage or necrotizing pancreatitis (5%), Crohn's disease and its complications (4%), trauma (traffic accidents, falls) (2%), diverticulitis and perforation (6%), nephrogenic diseases (4%), spontaneous pneumohepatic portal vein (2%), other reasons (4%). And after analysis, we found that the survival rate of patients treated by surgery was 40.5% and the mortality rate was 19.1%, the difference between the two was significant. CONCLUSIONS: Etiology should be actively explored and surgical treatment is necessary.

[Exploration on origin of Simiao Yong'an Decoction].

Simiao Yong'an Decoction is composed of Lonicerae Japonicae Flos, Scrophulariae Radix, Angelicae Sinensis Radix, Glycyrrhizae Radix et Rhizome, which was chosen as one of the 100 classic prescriptions in Catalogue of Ancient Classics Prescription(the first batch). Through tracing to the source, It was found that the Simiao Yong'an Decoction(but not named) originated from the Shi Shi Mi Lu, and was later cited by books such as Ancient and Modern Book Integration-Full Record of Medical Department and New Edition of Useful Prescriptions. Literature shows that this prescription was not named until first reported in the Effect of Traditional Chinese Medicine on Arterial Embolism Gangrene in 1956 by a journalist LYU Min. This article recorded that SHIJIA Baoshan, a monk from Hebei Province, used self-named "Simiao Yong'an Decoction" to treat local arterial embolic gangrene. After comparison, there was two difference between ancient books and SHIJIA Baoshan's records. Firstly, according to ancient books, the composition and dosage of Simiao Yong'an Decoction is Lonicerae Japonicae Flos 90 g, Scrophulariae Radix 90 g, Angelicae Sinensis Radix 60 g, Glycyrrhizae Radix et Rhizome 30 g", and the ratio is 3∶3∶2∶1. By SHIJIA Baoshan's record, the composition and dosage are: Lonicerae Japonicae Flos 66 g, Scrophulariae Radix 132 g, Angelicae Sinensis Radix 99 g, Glycyrrhizae Radix et Rhizome 33 g, and the ratio changed to 2∶4∶3∶1. Secondly, ancient books show that patients can be healed after taking seven or ten days of the previous prescription, however, it would take 3 or 4 months, even 7 months in SHIJIA Baoshan's records. It can be considered that the previous prescription should be used at the beginning of gangrene, while the modified Simiao Yong'an Decoction by SHIJIA Baoshan is widely used in the middle and late stages of gangrene, even the critical condition, that is the reason for longer treatment and larger dosage. Nowadays, Simiao Yong'an Decoction is not limited to the treatment of gangrene and bulla in clinic. Relevant studies have confirmed that Simiao Yong'an Decoction has the effects such as anti-inflammatory, plaque stabilization, lipid-lowering, vascular protection, improvement of hemorheology, anticoagulation, inhibition of thrombosis and fibrinolysis, etc. In the follow-up, we should carry out the analysis of the compatibility of this four medicines, and redefine the scope of its clinical application under the theory of traditional Chinese medicine.

l-Theanine and NEP1-40 promote nerve regeneration and functional recovery after brachial plexus root avulsion.

Brachial plexus root avulsion causes severe sequelae Treatments and prognosis face many problems, including inflammatory reaction, oxidative damage, and myelin related inhibitory effect. l-Theanine has anti-inflammatory, anti-oxidative, and neuroprotective effects. NEP1-40 competitively inhibits Nogo-66 receptor (NgR1) promotes axonal regeneration. Forty-eight Sprague-Dawley rats were randomly assigned into four groups to establish an animal model of brachial plexus root avulsion. Inflammation and oxidative damage were evaluated by spectrophotometry and motor function of the upper limbs was assessed via Terzis grooming test after modeling. Immunofluorescence and hematoxylin and eosin staining were utilized to determine the content of reactive oxygen species, activation of microglial cells, neuroprotection, and nerve regeneration. Compared with the control group, the L-Theanine + NEP1-40 group had significantly decreased myeloperoxidase, malondialdehyde, interleukin-6, reactive oxygen species, and microglial cells, significantly increased score on the Terzis grooming test, increased motor neuron content, and thickened muscle fibers, increased area, and appearance of large and clear motor endplate structures. The results of this study suggest that l-Theanine combined with NEP1-40significantly promoted nerve regeneration after brachial plexus root avulsion, and may be a potential treatment for promoting nerve regeneration. Possible mechanisms underlying these results are alleviation of oxidative damage and inflammatory responses in the injured area and antagonism of myelin inhibition.

Design and biomechanical characteristics of porous meniscal implant structures using triply periodic minimal surfaces.

BACKGROUND: Artificial meniscal implants can be used to replace a severely injured meniscus after meniscectomy and restore the normal functionality of a knee joint. The aim of this paper was to design porous meniscal implants and assess their biomechanical properties. METHODS: Finite element simulations were conducted on eight different cases including intact healthy knees, knee joints with solid meniscal implants, and knee joints with meniscal implants with two types of triply periodic minimal surfaces. Compression stresses, shear stresses, and characteristics of stress concentrated areas were evaluated using an axial compressive load of 1150 N and an anterior load of 350 N. RESULTS: Compared to the solid meniscal implant, the proposed porous meniscal implant produced lower levels of compression and shear stresses on the cartilage, which facilitated the cartilage to retain a semilunar characteristic similar to the natural meniscus. Moreover, both compression and shear stresses on the artificial cartilage were found to be sensitive to the pore properties of the meniscal implant. The meniscal implants with primitive surfaces (porosity: 41%) showed a better performance in disseminating stresses within the knee joint. CONCLUSION: The present commercial meniscal implant has the problem of equivalent biomechanical properties compared to natural menisci. The main advantage of the proposed porous structure is that it can be used to prevent excessive compression and shear stresses on the articular cartilages. This structure has advantages both in terms of mechanics and printability, which can be beneficial for future clinical applications.

[Study on interaction between ginsenosides Rg_1,Rb_1 and Ro and bovine serum albumin].

Small molecules with physiological or pharmacological activities need to interact with biological macromolecules in order to function in the body. As the protein with the highest proportion of plasma protein,serum albumin is the main protein binding to various endogenous or exogenous small molecules. Serum albumin interacts with small molecules in a reversible non-covalent manner and transports small molecules to target sites. Bovine serum albumin( BSA) is an ideal target protein for drug research because of its low cost and high homology with human serum albumin. The research on the interaction between drugs and BSA has become a hotspot in the fields of pharmacy,medicine,biology and chemistry. In this research,molecular docking method was used to study the interaction between three small ginsenosides with high pharmacological value( Rg_1,Rb_1,Ro) and bovine serum albumin( BSA),and the binding mode information of three ginsenosides interacting with BSA was obtained. The results of molecular docking showed that ginsenosides and amino acid residues in the active pocket of proteins could be combined by hydrophobic action,hydrogen bonding and electrostatic action. The interaction between small ginsenosides and bovine serum albumin is not the only form,and their interaction has many forms of force. The interaction between these molecules and various weak forces is the key factor for the stability of the complex. The results of this study can provide the structural information of computer simulation for the determination of the interaction patterns between active components and proteins of ginseng.

Intercellular signaling via cyclic GMP diffusion through gap junctions restarts meiosis in mouse ovarian follicles.

Meiosis in mammalian oocytes is paused until luteinizing hormone (LH) activates receptors in the mural granulosa cells of the ovarian follicle. Prior work has established the central role of cyclic GMP (cGMP) from the granulosa cells in maintaining meiotic arrest, but it is not clear how binding of LH to receptors that are located up to 10 cell layers away from the oocyte lowers oocyte cGMP and restarts meiosis. Here, by visualizing intercellular trafficking of cGMP in real-time in live follicles from mice expressing a FRET sensor, we show that diffusion of cGMP through gap junctions is responsible not only for maintaining meiotic arrest, but also for rapid transmission of the signal that reinitiates meiosis from the follicle surface to the oocyte. Before LH exposure, the cGMP concentration throughout the follicle is at a uniformly high level of ∼2-4 µM. Then, within 1 min of LH application, cGMP begins to decrease in the peripheral granulosa cells. As a consequence, cGMP from the oocyte diffuses into the sink provided by the large granulosa cell volume, such that by 20 min the cGMP concentration in the follicle is uniformly low, ∼100 nM. The decrease in cGMP in the oocyte relieves the inhibition of the meiotic cell cycle. This direct demonstration that a physiological signal initiated by a stimulus in one region of an intact tissue can travel across many layers of cells via cyclic nucleotide diffusion through gap junctions could provide a general mechanism for diverse cellular processes.

Mesoscale Structures in the Adlayer of A-B2 Heterogeneous Catalysis.

This article explores the adsorbate distributions in the adlayer for a model A-B2 system of heterogeneous catalysis, i.e., A + 1/2B2 → AB, via kinetic Monte Carlo (KMC) simulations. In comparison with our previous work on the A-B model (Sun, F.; Huang, W.; Li, J. Structural characteristics of the adlayer in heterogeneous catalysis. Chem. Eng. Sci. 2016, 153, 87-92), species B2 here brings about significant new features due to its special site requirement during adsorption and desorption and a different stoichiometric ratio in reactions. The effects of various kinetic processes on the adsorbate distribution are found to be similar to those in the A-B system; that is, both desorption and diffusion (besides adsorption) processes contribute to the adlayer uniformity while reactions account for clustering. However, desorption exhibits a stronger role than diffusion in homogenizing the adlayer, which is opposite to the finding in the previous A-B model. Under a fixed partial pressure, different reaction and desorption rate constants can lead to steady states with different dominant species, which has not been observed in the A-B system. The regime of species B poisoning shrinks as well, leading to the spreading of the coexisting regime, in comparison with the A-B model.

Comparative density functional theory-density functional tight binding study of fullerene derivatives: effects due to fullerene size, addends, and crystallinity on band structure, charge transport and optical properties.

We present a systematic comparative density functional theory-density functional tight binding study of multiple derivatives of C60 and C70 with different addends, in molecular as well as solid state. In particular, effects due to fullerene size, type and number of addends, and of crystallinity on band structure, charge transport, and optical properties are investigated. These are important, in particular, for rational selection of fullerene derivatives as acceptor and electron transport layers in organic as well as planar inverted perovskite solar cells. We find that by the choice of type and number of addends, one can modulate the LUMO within 0.4 eV. Changes in the HOMO can reach 0.7 eV. Substituting C70 for C60 results in destabilization of the HOMO by about 0.1 eV for indene and quinodimethane addends and by a less significant amount for PCBM addends. The effect of C70-C60 substitution on the LUMO is of similar magnitude. A more significant change in HOMO-LUMO energy is seen for the aryl addends. On the other hand, all C70 based molecules have strong visible absorption. For most addends, the crystal packing leads to a stabilization of both the LUMO and HOMO by about ∼0.2 and ∼0.1 eV, respectively, vs. single molecules. When using bis-addends, it is also possible to enhance the visible absorption. Electron and hole transport rates are computed to vary vastly depending on the addends chosen; specifically, we compute that indene and quimodimethane addends can enhance charge transport rates while the aryl addend is predicted to result in substantially smaller mobilities of electrons and holes, vs. PC60BM. Furthermore, the -CH2 and bisaddend addition can significantly enhance the charge transfer rates for the PCBM addend.

Dorsal root ganglion axon bifurcation tolerates increased cyclic GMP levels: the role of phosphodiesterase 2A and scavenger receptor Npr3.

A cyclic GMP (cGMP) signaling pathway, comprising C-type natriuretic peptide (CNP), its guanylate cyclase receptor Npr2, and cGMP-dependent protein kinase I, is critical for the bifurcation of dorsal root ganglion (DRG) and cranial sensory ganglion axons when entering the mouse spinal cord and the hindbrain respectively. However, the identity and functional relevance of phosphodiesterases (PDEs) that degrade cGMP in DRG neurons are not completely understood. Here, we asked whether regulation of the intracellular cGMP concentration by PDEs modulates the branching of sensory axons. Real-time imaging of cGMP with a genetically encoded fluorescent cGMP sensor, RT-PCR screens, in situ hybridization, and immunohistology combined with the analysis of mutant mice identified PDE2A as the major enzyme for the degradation of CNP-induced cGMP in embryonic DRG neurons. Tracking of PDE2A-deficient DRG sensory axons in conjunction with cGMP measurements indicated that axon bifurcation tolerates increased cGMP concentrations. As we found that the natriuretic peptide scavenger receptor Npr3 is expressed by cells associated with dorsal roots but not in DRG neurons itself at early developmental stages, we analyzed axonal branching in the absence of Npr3. In Npr3-deficient mice, the majority of sensory axons showed normal bifurcation, but a small population of axons (13%) was unable to form T-like branches and generated turns in rostral or caudal directions only. Taken together, this study shows that sensory axon bifurcation is insensitive to increases of CNP-induced cGMP levels and Npr3 does not have an important scavenging function in this axonal system.

Transgenic mice for cGMP imaging.

RATIONALE: Cyclic GMP (cGMP) is an important intracellular signaling molecule in the cardiovascular system, but its spatiotemporal dynamics in vivo is largely unknown. OBJECTIVE: To generate and characterize transgenic mice expressing the fluorescence resonance energy transfer-based ratiometric cGMP sensor, cGMP indicator with an EC50 of 500 nmol/L (cGi500), in cardiovascular tissues. METHODS AND RESULTS: Mouse lines with smooth muscle-specific or ubiquitous expression of cGi500 were generated by random transgenesis using an SM22α promoter fragment or by targeted integration of a Cre recombinase-activatable expression cassette driven by the cytomegalovirus early enhancer/chicken ß-actin/ß-globin promoter into the Rosa26 locus, respectively. Primary smooth muscle cells isolated from aorta, bladder, and colon of cGi500 mice showed strong sensor fluorescence. Basal cGMP concentrations were < 100 nmol/L, whereas stimulation with cGMP-elevating agents such as 2-(N,N-diethylamino)-diazenolate-2-oxide diethylammonium salt (DEA/NO) or the natriuretic peptides, atrial natriuretic peptide, and C-type natriuretic peptide evoked fluorescence resonance energy transfer changes corresponding to cGMP peak concentrations of ≈ 3 µmol/L. However, different types of smooth muscle cells had different sensitivities of their cGMP responses to DEA/NO, atrial natriuretic peptide, and C-type natriuretic peptide. Robust nitric oxide-induced cGMP transients with peak concentrations of ≈ 1 to > 3 µmol/L could also be monitored in blood vessels of the isolated retina and in the cremaster microcirculation of anesthetized mice. Moreover, with the use of a dorsal skinfold chamber model and multiphoton fluorescence resonance energy transfer microscopy, nitric oxide-stimulated vascular cGMP signals associated with vasodilation were detected in vivo in an acutely untouched preparation. CONCLUSIONS: These cGi500 transgenic mice permit the visualization of cardiovascular cGMP signals in live cells, tissues, and mice under normal and pathological conditions or during pharmacotherapy with cGMP-elevating drugs.

Preoperative and postoperative analgesic techniques in the treatment of patients undergoing transabdominal hysterectomy: a preliminary randomized trial.

BACKGROUND: Although pre-emptive analgesia is commonly used for the management of postoperative pain in developed countries, no defined protocol has been carried out and widely practiced, especially in transabdominal hysterectomy. Keeping this in mind the present study aimed to investigate the effects of multimodal pre-emptive analgesia on pain management, stress response and inflammatory factors of patients undergoing transabdominal hysterectomy to find an optimized way of pre-emptive analgesia. METHODS: One hundred patients undergoing abdominal hysterectomy were randomly divided into four groups (Trial registration: ChiCTR-IPR-15005848). Group P1 was given intravenous flurbiprofen and epidural fentanyl + ketamine before surgery; Group P2 received intravenous flurbiprofen before surgery and epidural fentanyl + ketamine after surgery; Group P3 was given epidural fentanyl + ketamine before surgery and intravenous flurbiprofen after surgery; Patients in Group C received normal saline treatment. RESULTS: Compared with control group, the first time to request additional analgesics after surgery were significantly later (P < 0.05), 24 h dosage of analgesia were significantly less (P < 0.05), VAS score at all time periods after surgery were significantly lower (P < 0.05) in Group P1, P2, or P3. At 12 h or 24 h after surgery, VAS score in Group P1 was significantly lower than that in group P2 or P3 (P < 0.05, P < 0.05). No significant adverse effects were found among the groups (P > 0.05). At 1 or 2 days after surgery, the levels of cortisol, glucose, and IL-6, TNF-α in group P1, P2, and P3 were significantly lower than those in group C (P < 0.05); while, the levels in group P2, P3 were significantly lower than those in group P1 (P < 0.05). CONCLUSION: Multimodal pre-emptive analgesia could significantly lower VAS score, inhibit stress response, and reduce inflammatory response in patients undergoing transabdominal hysterectomy, which can be a rational strategy for pain control in future. TRIAL REGISTRATION: ChiCTR-IPR-15005848 on January 17, 2015.

Poliumoside protects against type 2 diabetes-related osteoporosis by suppressing ferroptosis via activation of the Nrf2/GPX4 pathway.

BACKGROUND: Type 2 diabetes is often linked with osteoporosis (T2DOP), a condition that accelerates bone degeneration and increases the risk of fractures. Unlike conventional menopausal osteoporosis, the diabetic milieu exacerbates the likelihood of fractures and osteonecrosis. In particular poliumoside (Pol), derived from Callicarpa kwangtungensis Chun, has shown promising anti-oxidant and anti-inflammatory effects. Yet, its influence on T2DOP remains to be elucidated. PURPOSE: The focus of this study was to elucidate the influence of Pol in HGHF-associated ferroptosis and its implications in T2DOP. STUDY DESIGN: A murine model of T2DOP was established using a minimal dosage of streptozotocin (STZ) through intraperitoneal infusion combined with a diet high in fat and sugar. Concurrently, to mimic the diabetic condition in a lab environment, bone mesenchymal stem cells (BMSCs) were maintained in a high-glucose and high-fat (HGHF) setting. METHODS: The impact of Pol on BMSCs in an HGHF setting was determined using methods, such as BODIPY-C11, FerroOrange staining, mitochondrial functionality evaluations, and Western blot methodologies, coupled with immunoblotting and immunofluorescence techniques. To understand the role of Pol in a murine T2DOP model, techniques including micro-CT, hematoxylin and eosin (H&E) staining, dual-labeling with calcein-alizarin red, and immunohistochemistry were employed for detailed imaging and histological insights. RESULTS: Our findings suggest that Pol acts against HGHF-induced bone degradation and ferroptosis, as evidenced by an elevation in glutathione (GSH) and a decline in malondialdehyde (MDA) levels, lipid peroxidation, and mitochondrial reactive oxygen species (ROS). Furthermore, Pol treatment led to increased bone density, enhanced GPX4 markers, and reduced ROS in the distal femur region. On investigating the underlying mechanism of action, it was observed that Pol triggers the Nrf2/GPX4 pathway, and the introduction of lentivirus-Nrf2 negates the beneficial effects of Pol in HGHF-treated BMSCs. CONCLUSION: Pol is effective in treating T2DOP by activating the Nrf2/GPX4 signaling pathway to inhibit ferroptosis.

Kindlin2 enables EphB/ephrinB bi-directional signaling to support vascular development.

Direct contact between cells expressing either ephrin ligands or Eph receptor tyrosine kinase produces diverse developmental responses. Transmembrane ephrinB ligands play active roles in transducing bi-directional signals downstream of EphB/ephrinB interaction. However, it has not been well understood how ephrinB relays transcellular signals to neighboring cells and what intracellular effectors are involved. Here, we report that kindlin2 can mediate bi-directional ephrinB signaling through binding to a highly conserved NIYY motif in the ephrinB2 cytoplasmic tail. We show this interaction is important for EphB/ephrinB-mediated integrin activation in mammalian cells and for blood vessel morphogenesis during zebrafish development. A mixed two-cell population study revealed that kindlin2 (in ephrinB2-expressing cells) modulates transcellular EphB4 activation by promoting ephrinB2 clustering. This mechanism is also operative for EphB2/ephrinB1, suggesting that kindlin2-mediated regulation is conserved for EphB/ephrinB signaling pathways. Together, these findings show that kindlin2 enables EphB4/ephrinB2 bi-directional signal transmission.

Sacrificial scaffold-assisted direct ink writing of engineered aortic valve prostheses.

Heart valve disease has become a serious global health problem, which calls for numerous implantable prosthetic valves to fulfill the broader needs of patients. Although current three-dimensional (3D) bioprinting approaches can be used to manufacture customized valve prostheses, they still have some complications, such as limited biocompatibility, constrained structural complexity, and difficulty to make heterogeneous constructs, to name a few. To overcome these challenges, a sacrificial scaffold-assisted direct ink writing approach has been explored and proposed in this work, in which a sacrificial scaffold is printed to temporarily support sinus wall and overhanging leaflets of an aortic valve prosthesis that can be removed easily and mildly without causing any potential damages to the valve prosthesis. The bioinks, composed of alginate, gelatin, and nanoclay, used to print heterogenous valve prostheses have been designed in terms of rheological/mechanical properties and filament formability. The sacrificial ink made from Pluronic F127 has been developed by evaluating rheological behavior and gel temperature. After investigating the effects of operating conditions, complex 3D structures and homogenous/heterogenous aortic valve prostheses have been successfully printed. Lastly, numerical simulation and cycling experiments have been performed to validate the function of the printed valve prostheses as one-way valves.

3D printing-based full-scale human brain for diverse applications.

Surgery is the most frequent treatment for patients with brain tumors. The construction of full-scale human brain models, which is still challenging to realize via current manufacturing techniques, can effectively train surgeons before brain tumor surgeries. This paper aims to develop a set of three-dimensional (3D) printing approaches to fabricate customized full-scale human brain models for surgery training as well as specialized brain patches for wound healing after surgery. First, a brain patch designed to fit a wound's shape and size can be easily printed in and collected from a stimuli-responsive yield-stress support bath. Then, an inverse 3D printing strategy, called "peeling-boiled-eggs," is proposed to fabricate full-scale human brain models. In this strategy, the contour layer of a brain model is printed using a sacrificial ink to envelop the target brain core within a photocurable yield-stress support bath. After crosslinking the contour layer, the as-printed model can be harvested from the bath to photo crosslink the brain core, which can be eventually released by liquefying the contour layer. Both the brain patch and full-scale human brain model are successfully printed to mimic the scenario of wound healing after removing a brain tumor, validating the effectiveness of the proposed 3D printing approaches.