Development of a New Tool for 3D Modeling for Regenerative Medicine

The effectiveness of therapeutic treatment based on regenerative medicine for degenerative diseases (i.e., neurodegenerative or cardiac diseases) requires tools allowing the visualization and analysis of the three-dimensional (3D) distribution of target drugs within the tissue. Here, we present a new computational procedure able to overcome the limitations of visual analysis emerging by the examination of a molecular signal within images of serial tissue/organ sections by using the conventional techniques. Together with the 3D anatomical reconstitution of the tissue/organ, our framework allows the detection of signals of different origins (e.g., marked generic molecules, colorimetric, or fluorimetric substrates for enzymes; microRNA; recombinant protein). Remarkably, the application does not require the employment of specific tracking reagents for the imaging analysis. We report two different representative applications: the first shows the reconstruction of a 3D model of mouse brain with the analysis of the distribution of the β-Galactosidase, the second shows the reconstruction of a 3D mouse heart with the measurement of the cardiac volume

Biomechanical behaviour of native and sutured bronchi: An in-vitro study

BACKGROUND: Biomechanical behaviour evaluation of a suture is an important information for the surgeon to choose the best technique to perform. OBJECTIVE: To assess the biomechanical behavior of the native and mechanically sutured bronchi. METHODS: Ten bronchi were harvested from slaughtered pigs and then randomly separated in two groups, a control intact group and a sutured group where specimens were cut in half and sutured, to evaluate mechanical properties during a tensile test using a loading frame machine. In addition optoelectric motion tracking system was used to evaluate suture profile motion during the test. RESULTS: Significant differences (p < 0.05) were found between the two groups for the parameters investigated. The control group showed a higher maximal stress resistance and stiffness than the suture group, while elongation at rupture was increased in the sutured group. All the sutures broke in symmetric manner, as the mean of the side difference of the sutured specimens was 0.93 ± 0.80 mm at rupture. CONCLUSIONS: Biomechanical behaviour of native and sutured bronchi was evaluated, giving highly reproducible parameters regarding mechanical properties that may help clinicians and bioengineers to rationalize the choice for a particular suture material or suture technique, increasing surgical outcomes

Biomechanical behaviour of native and sutured bronchi. An in-vitro study

BACKGROUND: Biomechanical behaviour evaluation of a suture is an important information for the surgeon to choose the best technique to perform. OBJECTIVE: To assess the biomechanical behavior of the native and mechanically sutured bronchi. METHODS: Ten bronchi were harvested from slaughtered pigs and then randomly separated in two groups, a control intact group and a sutured group where specimens were cut in half and sutured, to evaluate mechanical properties during a tensile test using a loading frame machine. In addition optoelectric motion tracking system was used to evaluate suture profile motion during the test. RESULTS: Significant differences (p < 0.05) were found between the two groups for the parameters investigated. The control group showed a higher maximal stress resistance and stiffness than the suture group, while elongation at rupture was increased in the sutured group. All the sutures broke in symmetric manner, as the mean of the side difference of the sutured specimens was 0.93 ± 0.80 mm at rupture. CONCLUSIONS: Biomechanical behaviour of native and sutured bronchi was evaluated, giving highly reproducible parameters regarding mechanical properties that may help clinicians and bioengineers to rationalize the choice for a particular suture material or suture technique, increasing surgical outcomes

www.mdpi.com/journal/jfb/ Review Mechanotransduction: Tuning Stem Cells Fate

Abstract: It is a general concern that the success of regenerative medicine-based applications is based on the ability to recapitulate the molecular events that allow stem cells to repair the damaged tissue/organ. To this end biomaterials are designed to display properties that, in a precise and physiological-like fashion, could drive stem cell fate both in vitro and in vivo. The rationale is that stem cells are highly sensitive to forces and that they may convert mechanical stimuli into a chemical response. In this review, we describe novelties on stem cells and biomaterials interactions with more focus on the implication of the mechanical stimulation named mechanotransduction

Efficient siRNA Delivery by the Cationic Liposome DOTAP in Human Hematopoietic Stem Cells Differentiating into Dendritic Cells

RNA interference technology is an ideal strategy to elucidate the mechanisms associated with human CD34+ hematopoietic stem cell differentiation into dendritic cells. Simple manipulations in vitro can unequivocally yield alloreactive or tolerogenic populations, suggesting key implications of biochemical players that might emerge as therapeutic targets for cancer or graft-versus-host disease. To knockdown proteins typically involved in the biology of dendritic cells, we employed an siRNA delivery system based on the cationic liposome DOTAP as the carrier. Freshly-isolated CD34+ cells were transfected with siRNA for cathepsin S with negligible cytotoxicity and transfection rates (>60%) comparable to the efficiency shown by lentiviral vectors. Further, cathepsin S knockdown was performed during both cell commitment and through the entire 14-day differentiation process with repeated transfection rounds that had no effect per se on cell development. Tested in parallel, other commercially-available chemical reagents failed to meet acceptable standards. In addition to safe and practical handling, a direct advantage of DOTAP over viral-mediated techniques is that transient silencing effects can be dynamically appraised through the recovery of targeted proteins. Thus, our findings identify DOTAP as an excellent reagent for gene silencing in resting and differentiating CD34+ cells, suggesting a potential for applications in related preclinical models

Mechanotransduction: Tuning Stem Cells Fate

It is a general concern that the success of regenerative medicine-based applications is based on the ability to recapitulate the molecular events that allow stem cells to repair the damaged tissue/organ. To this end biomaterials are designed to display properties that, in a precise and physiological-like fashion, could drive stem cell fate both in vitro and in vivo. The rationale is that stem cells are highly sensitive to forces and that they may convert mechanical stimuli into a chemical response. In this review, we describe novelties on stem cells and biomaterials interactions with more focus on the implication of the mechanical stimulation named mechanotransduction

A Novel Approach for Patellofemoral Tracking Using a Knee Model Reconstructed with a Three-Dimensional Printer

This study proposes a new approach to evaluate the patellofemoral tracking using a knee model composed of femur, tibia, and patella reconstructed with a three-dimensional (3D) printer. Magnetic resonance images were used to create a CAD (Computer-Aided Design) file that is subsequently used as input for a 3D printer machine. Artificial ligaments were used to mimic the stability of the knee. The quadriceps tendon was simulated using a polyvinylchloride cord attached to the tibial insertion and the patella. The model was fixed to a tensile test machine and four static tests were performed by applying 200\u2009N load in the proximal\u2013distal direction through the cord at 30\ub0, 60\ub0, and 90\ub0 of knee flexion. The position of the patella was measured using a motion-tracking system with a custom-made navigation system. The mediolateral displacement of the patella was 1.01\u2009\ub1\u20090.13\u2009mm at 30\ub0 of knee flexion and 7.99\u2009\ub1\u20090.07\u2009mm at 90\ub0 of flexion. The patella lateral tilt was 2.79\ub0\u2009\ub1\u20090.67\ub0 at 30\ub0 of flexion and 6.42\ub0\u2009\ub1\u20090.11\ub0 at 90\ub0 of flexion. In conclusion, our low-cost knee model closely simulates the patellar behavior of cadaveric specimens as the results are in agreement with literature data on similar static in vitro experiments