Safety and function of a new pre-vascularized bioartificial pancreas in an allogeneic rat model.

Cell encapsulation could overcome limitations of free islets transplantation but is currently limited by inefficient cells immune protection and hypoxia. As a response to these challenges, we tested in vitro and in vivo the safety and efficacy of a new macroencapsulation device named MailPan®. Membranes of MailPan® device were tested in vitro in static conditions. Its bio-integration and level of oxygenation was assessed after implantation in non-diabetic rats. Immune protection properties were also assessed in rat with injection in the device of allogeneic islets with incompatible Major Histocompatibility Complex. Finally, function was assessed in diabetic rats with a Beta cell line injected in MailPan®. In vitro, membranes of the device showed high permeability to glucose, insulin, and rejected IgG. In rat, the device displayed good bio-integration, efficient vascularization, and satisfactory oxygenation (>5%), while positron emission tomography (PET)-scan and angiography also highlighted rapid exchanges between blood circulation and the MailPan®. The device showed its immune protection properties by preventing formation, by the rat recipient, of antibodies against encapsulated allogenic islets. Injection of a rat beta cell line into the device normalized fasting glycemia of diabetic rat with retrieval of viable cell clusters after 2 months. These data suggest that MailPan® constitutes a promising encapsulation device for widespread use of cell therapy for type 1 diabetes.

The Simulation Training in Coronary Angiography and Its Impact on Real Life Conduct in the Catheterization Laboratory.

Our study aimed to evaluate the effectiveness of mentored simulation training (ST) in coronary angiography and to assess the transferability of acquired skills from virtual reality to the real world. Twenty cardiology residents were randomized to ST or control before performing real-life cases in the catheterization laboratory. The control group underwent secondary ST and reperformed real-life cases in the catheterization laboratory. Skill metrics were compared between the ST and the control group, and within the control group between before and after ST. In real-life cases, the procedure time was shorter (p = 0.002), the radiation dose lower (p = 0.001), and the global procedure skill score was higher (p = 0.0001) in the ST group as compared with the control (before ST) group. During virtual ST procedural time (p <0.001), fluoroscopic time (p <0.001), training contrast amount (p <0.001), and global training score (p <0.001) significantly decreased. In the control group, all monitoring procedure parameters were significantly improved after ST, as well as, the global procedure flow score (p <0.0001). In conclusion, simulator-based training in coronary angiography improved operator skills compared with traditional in catheterization laboratory mentor-based training. ST should be incorporated in the curriculum of the interventionalist to improve learning in coronary angiography.

Development of a porcine beating-heart model of self-myocardial retroperfusion: evaluation of hemodynamic and cardiac responses to ischemia and clinical applications.

BACKGROUND: Retrograde perfusion into the coronary sinus is used to deliver cardioplegia. We developed an in-vivo porcine beating-heart model of self-myocardial retroperfusion (SMR) using the venous route to supply myocardial oxygenation and sought to assess hemodynamic and cardiac responses triggered by SMR before and after a prolonged occlusion of the LAD. METHODS: A bypass-line between the ascending aorta and the coronary sinus was made to perform a selective retrograde perfusion of the great cardiac vein with oxygenated blood (SMR). A Control group (N.=6) was assigned to collect baseline data, and an SMR group (N.=6) was dedicated to undergo SMR with occlusion of LAD for 240 minutes. Cardiac output (CO), maximal pressure in the LV (Pmax in-LV), stroke volume (SV), left ventricular ejection fraction (LVEF), diastolic durations, heart rate, and arterial systemic pressure were evaluated with conductance catheters for the following periods: basal (before SMR), SMR with patent LAD, and SMR with occluded LAD. In order to assess peripheral perfusion, patterns of sublingual microcirculation were analyzed. At the end of the procedures, the hearts were harvested for histology. RESULTS: Echographic LVEF evaluation was affected by sternotomy, but conductance catheter evaluation was not. Following pericardiotomy, CO decreased by 7.51% (P<0.05). SMR with patent LAD showed inotropic properties with improvements in CO, SV, Pmax in-LV and LVEF (P<0.0001). Following LAD occlusion, SMR supplied myocardial oxygenation with hemodynamic compensation and preserved the peripheral perfusion. Histology confirmed no signs of infarct. CONCLUSIONS: SMR showed capacities to produce inotropic effects and protect against ischemia, opening interesting perspectives.