Budding Uninhibited by Benzimidazole-1 Insufficiency Prevents Acute Renal Failure in Severe Sepsis by Maintaining Anticoagulant Functions of Vascular Endothelial Cells.

Severe sepsis is critical to health and can result in acute renal failure (ARF). Tissue factor (TF) and thrombomodulin (TM) play key roles in vascular endothelial functions by helping maintain microcirculation in the kidney. Budding uninhibited by benzimidazole-1 (Bub1) plays a role in Akt and JNK signaling, which control TF and TM, respectively. We hypothesized that Bub1 could control vascular endothelial function in sepsis. The aim of this study was to determine the role of Bub1 in septic ARF. We used Mouse cecum ligation and puncture (CLP) using low Bub1 expressing (Bub1) and wild-type (Bub1) mice in vivo and lipopolysaccharide (LPS) stimulation of human aortic endothelial cell (HAEC) in vitro. Bub1 mice had a higher survival rate after CLP than Bub1. Bub1 mice had more severe ARF after CLP than Bub1 with blood biochemical and pathological analyses. TF expression in Bub1 mice and control HAEC (control) significantly increased in the septic model compared with Bub1 and Bub1 silenced HAEC (siBub1). TM expression in the control significantly decreased after LPS stimulation compared with siBub1. Akt and JNK phosphorylation of siBub1 were attenuated after LPS stimulation. Associations of Bub1 with Akt or JNK after LPS stimulation of HAEC were detected using immunoprecipitation, suggesting that Bub1 is involved in the phosphorylation of Akt and JNK after LPS stimulation. Bub1 insufficiency attenuates TF expression and reduces TM suppression by blocking Akt and JNK phosphorylation, respectively, thus leading to the prevention of ARF and death caused by sepsis.

Real-time in vitro intravascular reconstruction and navigation for endovascular aortic stent grafting.

BACKGROUND: Trans-catheter endovascular stent grafting minimizes trauma and increases the benefitting patient population. However, the alignment between stent graft branches and vasculature branches remains time-consuming and challenging, and such techniques require a significant amount of contrast agent for imaging. METHODS: A new framework for intravascular reconstruction based on sensor fusion between intravascular ultrasound (IVUS) imaging and electromagnetic (EM) tracking was proposed. A new image processing method was presented to realize fully automatic processing of IVUS imaging and 3D reconstruction in real time, as well as branch detection for alignment and deployment. Complementary navigation using CT data allows for efficient catheter advancement and assistant clinical judgement. RESULTS: The reconstruction of an in vitro descending aorta phantom with branches was realized at 35 Hz, with cross-section radius average error of 0.64 mm. CONCLUSION: The proposed method demonstrates significant potential for clinical applications, enables navigation for precise alignment and placement for stent grafting to reduce surgical time, and decreases hemorrhagic collisions and the use of contrast agent. Copyright © 2016 John Wiley & Sons, Ltd.

PD-L1 Is Upregulated by Simultaneous Amplification of the PD-L1 and JAK2 Genes in Non-Small Cell Lung Cancer.

OBJECTIVES: The programmed death ligand 1(PD-L1)/programmed cell death protein 1 (PD-1) pathway is one of the most important checkpoint pathways for mediating tumor-induced immune suppression through T-cell exhaustion. Recently, targeted therapies using monoclonal antibodies against components of this pathway have been shown to reduce tumor burden in patients with non-small cell lung cancer (NSCLC). However, the prognostic significance of PD-L1 expression is controversial and the precise mechanisms of PD-L1 gene activation in lung cancer have yet to be clarified. METHODS: We investigated copy number alterations (CNAs) in the PD-L1 gene by real-time PCR in 94 surgically resected lung cancer samples to find possible associations between PD-L1 CNA and lung cancer biology. Janus kinase 2 gene (JAK2) CNA and its influence on the PD-L1/PD-1 pathway were also assessed. RESULTS: Five samples were shown to have PD-L1 gene amplification, whereas 89 samples did not. The patients with PD-L1 amplification had worse prognoses than did those without PD-L1 amplification. Genetic amplification of the PD-L1 gene was correlated with JAK2 gene amplification. The lung cancer cell line HCC4006 was found to harbor both JAK2 and PD-L1 amplification. Flow cytometry analyses revealed the level of PD-L1 protein expression to be higher in HCC4006 cells than in other NSCLC cell lines. Expression of the PD-L1 protein was significantly reduced by the JAK2 inhibitor TG-101348 and the signal transducer and activator of transcription 3 (STAT-3) inhibitor BP-1-102, but not by the STAT1 inhibitor fludarabine. CONCLUSIONS: Our data suggest that expression of PD-L1 protein is upregulated by the simultaneous amplification of the PD-L1 and JAK2 genes through JAK-STAT signaling in NCSLC.

In vitro simulator with numerical stress analysis for evaluation of stent-assisted coiling embolization in cerebral aneurysm treatments.

BACKGROUND: There are several complications associated with Stent-assisted Coil Embolization (SACE) in cerebral aneurysm treatments, due to damaging operations by surgeons and undesirable mechanical properties of stents. Therefore, it is necessary to develop an in vitro simulator that provides both training and research for evaluating the mechanical properties of stents. METHODS: A new in vitro simulator for three-dimensional digital subtraction angiography was constructed, followed by aneurysm models fabricated with new materials. Next, this platform was used to provide training and to conduct photoelastic stress analysis to evaluate the SACE technique. RESULTS: The average interaction stress increasingly varied for the two different stents. Improvements for the Maximum-Likelihood Expectation-Maximization method were developed to reconstruct cross-sections with both thickness and stress information. CONCLUSIONS: The technique presented can improve a surgeon's skills and quantify the performance of stents to improve mechanical design and classification. This method can contribute to three-dimensional stress and volume variation evaluation and assess a surgeon's skills.

Active control of microbubbles stream in multi-bifurcated flow by using 2D phased array ultrasound transducer.

We have previously reported our attempt to propel microbbles in flow by a primary Bjerknes force, which is a physical phenomenon where an acoustic wave pushes an obstacle along its direction of propagation. However, when ultrasound was emitted from surface of the body, controlling bubbles in against flow was needed. It is unpractical to use multiple transducers to produce the same number of focal points because single element transducer cannot produce more than two focal points. In this study, we introduced a complex artificial blood vessel according to a capillary model and a 2D array transducer to produce multiple focal points for active control of microbubbles in against flow. Furthermore, we investigated bubble control in viscous fluid. As the results, we confirmed clearly path selection of MBs in viscous fluid as well as in water.

In vitro strain measurements in cerebral aneurysm models for cyber-physical diagnosis.

BACKGROUND: The development of new diagnostic technologies for cerebrovascular diseases requires an understanding of the mechanism behind the growth and rupture of cerebral aneurysms. To provide a comprehensive diagnosis and prognosis of this disease, it is desirable to evaluate wall shear stress, pressure, deformation and strain in the aneurysm region, based on information provided by medical imaging technologies. METHODS: In this research, we propose a new cyber-physical system composed of in vitro dynamic strain experimental measurements and computational fluid dynamics (CFD) simulation for the diagnosis of cerebral aneurysms. A CFD simulation and a scaled-up membranous silicone model of a cerebral aneurysm were completed, based on patient-specific data recorded in August 2008. In vitro blood flow simulation was realized with the use of a specialized pump. A vision system was also developed to measure the strain at different regions on the model by way of pulsating blood flow circulating inside the model. RESULTS: Experimental results show that distance and area strain maxima were larger near the aneurysm neck (0.042 and 0.052), followed by the aneurysm dome (0.023 and 0.04) and finally the main blood vessel section (0.01 and 0.014). These results were complemented by a CFD simulation for the addition of wall shear stress, oscillatory shear index and aneurysm formation index. Diagnosis results using imaging obtained in August 2008 are consistent with the monitored aneurysm growth in 2011. CONCLUSION: The presented study demonstrates a new experimental platform for measuring dynamic strain within cerebral aneurysms. This platform is also complemented by a CFD simulation for advanced diagnosis and prediction of the growth tendency of an aneurysm in endovascular surgery.

Biodegradable porous sheet-like scaffolds for soft-tissue engineering using a combined particulate leaching of salt particles and magnetic sugar particles.

Scaffolds serving as artificial extracellular matrixes (ECMs) play a pivotal role in the process of tissue regeneration by providing optimal cellular environments for penetration, ingrowth, and vascularization. Stacks of sheet-like scaffold can be engineered to become artificial ECMs, suggesting a great potential for achieving complex 3-D tissue regeneration to support cell survival and growth. In this study, we proposed and investigated a combined particulate leaching of magnetic sugar particles (MSPs) and salt particles for the development of a sheet-like scaffold. MSPs were fabricated by encapsulating NdFeB particles inside sugar spheres and were controlled using magnetic fields as a porogen to control pore size, pore structure and pore density while fabricating the scaffold. We studied the influence of the strength of the magnetic fields in controlling the coating thickness of the unmagnetized MSPs during the fabrication of the sheet-like scaffolds. The experimental relationship between magnetic flux density and the thickness of the MSP layer was illustrated. Furthermore, we investigated the infiltration capacity of different concentrations of poly(L-lactide-co-ɛ-caprolactone) (PLCL) as a scaffold material on MSP clusters. Following polymer casting and removal of the sugar template, spherical pores were generated inside the scaffolds. Cultivation of NIH/3T3 fibroblasts on the fabricated scaffold proves that the proposed method can be applied in the cell sheet fabrication.

Technical skills measurement based on a cyber-physical system for endovascular surgery simulation.

BACKGROUND: Quantification of medical skills is a challenge, particularly simulator-based training. In the case of endovascular intervention, it is desirable that a simulator accurately recreates the morphology and mechanical characteristics of the vasculature while enabling scoring. METHODS: For this purpose, we propose a cyber-physical system composed of optical sensors for a catheter's body motion encoding, a magnetic tracker for motion capture of an operator's hands, and opto-mechatronic sensors for measuring the interaction of the catheter tip with the vasculature model wall. Two pilot studies were conducted for measuring technical skills, one for distinguishing novices from experts and the other for measuring unnecessary motion. RESULTS: The proficiency levels were measurable between expert and novice and also between individual novice users. The results enabled scoring of the user's proficiency level, using sensitivity, reaction time, time to complete a task and respect for tissue integrity as evaluation criteria. Additionally, unnecessary motion was also measurable. CONCLUSION: The development of cyber-physical simulators for other domains of medicine depend on the study of photoelastic materials for human tissue modelling, and enables quantitative evaluation of skills using surgical instruments and a realistic representation of human tissue.

Development of biodegradable scaffolds based on magnetically guided assembly of magnetic sugar particles.

Biodegradable scaffolds with controlled pore layout and porosity have great significance in tissue engineering for cell penetration, tissue ingrowth, vascularization, and nutrient delivery. Porogen leaching has been commonly used to control pore size, pore structure and porosity in the scaffold. In this paper we focus on the use/development of two magnetically guided porogen assembly methods using magnetic sugar particles (MSPs) for scaffold fabrication. First, a patterning device is utilized to align MSPs following designed templates. Then a magnetic sheet film is fabricated by mixing poly(vinyl alcohol, PVA) and NdFeB powder for steering the MSPs. After poly(l-lactide-co-ɛ-caprolactone) (PLCL) casting and removal of the sugar template, a scaffold with spherical pores is obtained. The surface and the inner structure of the scaffolds are evaluated using light and electron micrographs showing their interconnection of pores, pore wall morphology and porosity. Single layer scaffolds with the size of 8mm in width and 10mm in length were constructed with controllable pore diameters in the ranges of 105-150 µm, 250-300 µm and 425-500 µm.

In vitro three-dimensional aortic vasculature modeling based on sensor fusion between intravascular ultrasound and magnetic tracker.

BACKGROUND: It is desirable to reduce aortic stent graft installation time and the amount of contrast media used for this process. Guidance with augmented reality can achieve this by facilitating alignment of the stent graft with the renal and mesenteric arteries. METHODS: For this purpose, a sensor fusion is proposed between intravascular ultrasound (IVUS) and magnetic trackers to construct three-dimensional virtual reality models of the blood vessels, as well as improvements to the gradient vector flow snake for boundary detection in ultrasound images. In vitro vasculature imaging experiments were done with hybrid probe and silicone models of the vasculature. RESULTS: The dispersion of samples for the magnetic tracker in the hybrid probe increased less than 1 mm when the IVUS was activated. Three-dimensional models of the descending thoracic aorta, with cross-section radius average error of 0.94 mm, were built from the data fusion. CONCLUSION: The development of this technology will enable reduction in the amount of contrast media required for in vivo and real-time three-dimensional blood vessel imaging.

Observation of flow variation in capillaries of artificial blood vessel by producing microbubble aggregations.

Microbubbles form their aggregations between the neighboring microbubbles by the effect of secondary Bjerknes force under ultrasound exposure. However, because of the difficulty to reproduce a capillary-mimicking artificial blood vessel, the behavior of aggregations in a capillary has not been predicted. Thus we prepared artificial blood vessels including a capillary model, which was made of poly(vinyl alcohol) (PVA) by grayscale lithography method, with minimum diameter of the path of 0.5 mm. By using this model we investigated the possibility of artificial embolization, where the microbubble aggregations might block entire vessels not to penetrate flow in downstream. Confirming that the sizes of flown aggregation were greater than the section area of the minimum path in the capillary model, we investigated the probability of path block in it. As the results we confirmed the probability increased in proportion to sound pressure and inversely to flow velocity. We are going to investigate with more kinds of parameters to enhance the possibility of artificial embolization.

Multiscale fabrication of a transparent circulation type blood vessel simulator.

We proposed and fabricated multiscale transparent arteriole and capillary vessel models with circular cross sections of 10-500 µm using photolithography. The circularities of the fabricated 10, 50, and 500 µm diameter microchannels were 84.0%, 61.5%, and 82.3%, respectively. Next, we connected these different models to realize a circulation type blood vessel model simulating arteriole networks. We proposed a novel connection method using an intermediate connector made of wax, which we used to connect these models to make a circulation model. In flow experiments, the fabricated models showed no leakage and circulation models with seamless connections were achieved.

Development of biodegradable scaffolds based on patient-specific arterial configuration.

Biodegradable scaffolds are of great value in tissue engineering. We have developed a method for fabricating patient-specific vascular scaffolds from a biocompatible and biodegradable polymer, poly(L-lactide-co-epsilon-caprolactone). This method's usefulness is due to flexibility in the choice of materials and vascular configurations. Here, we present a way to fabricate scaffolds of human carotid artery by combining processes of rapid prototyping, lost wax, dip coating, selective dissolution, and salt leaching. The result was the successful development of porous biodegradable scaffolds, with mechanical strength covering the range of human blood vessels (1-3 MPa). Human umbilical vein endothelial cells were also cultured on the scaffolds and their biocompatibility was confirmed by cell growth. The Young's modulus of scaffolds could be controlled by changing polymer concentration and porosity. The wall thickness of the tubular scaffold was also controllable by adjusting polymer concentration and pull-up velocity during dip coating. We believe that this fabrication technique can be applied to patient-specific regeneration of blood vessels.

An in vitro patient-tailored model of human cerebral artery for simulating endovascular intervention.

An in vitro patient-tailored reproduction model of cerebral artery, a hardware platform for simulating endovascular intervention for making diagnoses and surgical trainings is presented. 3-D configuration of vessel lumen is reproduced as vessel model with 13 microm modeling resolution, using CT and MRI information. Physical characteristics of cerebral artery, such as elastic modulus and friction coefficient, are also reproduced. We also propose a novel method to visualize stress condition on vessel wall using photoelastic effect. Consequently, it should be helpful for clinical applications, academic researches and other various purposes.