Nanopatterned acellular valve conduits drive the commitment of blood-derived multipotent cells

Considerable progress has been made in recent years toward elucidating the correlation among nanoscale topography, mechanical properties, and biological behavior of cardiac valve substitutes. Porcine TriCol scaffolds are promising valve tissue engineering matrices with demonstrated self-repopulation potentiality. In order to define an in vitro model for investigating the influence of extracellular matrix signaling on the growth pattern of colonizing blood-derived cells, we cultured circulating multipotent cells (CMC) on acellular aortic (AVL) and pulmonary (PVL) valve conduits prepared with TriCol method and under no-flow condition. Isolated by our group from Vietnamese pigs before heart valve prosthetic implantation, porcine CMC revealed high proliferative abilities, three-lineage differentiative potential, and distinct hematopoietic/endothelial and mesenchymal properties. Their interaction with valve extracellular matrix nanostructures boosted differential messenger RNA expression pattern and morphologic features on AVL compared to PVL, while promoting on both matrices the commitment to valvular and endothelial cell-like phenotypes. Based on their origin from peripheral blood, porcine CMC are hypothesized in vivo to exert a pivotal role to homeostatically replenish valve cells and contribute to hetero- or allograft colonization. Furthermore, due to their high responsivity to extracellular matrix nanostructure signaling, porcine CMC could be useful for a preliminary evaluation of heart valve prosthetic functionality

Fine Structure of Glycosaminoglycans from Fresh and Decellularized Porcine Cardiac Valves and Pericardium

Cardiac valves are dynamic structures, exhibiting a highly specialized architecture consisting of cells and extracellular matrix with a relevant proteoglycan and glycosaminoglycan content, collagen and elastic fibers. Biological valve substitutes are obtained from xenogenic cardiac and pericardial tissues. To overcome the limits of such non viable substitutes, tissue engineering approaches emerged to create cell repopulated decellularized scaffolds. This study was performed to determine the glycosaminoglycans content, distribution, and disaccharides composition in porcine aortic and pulmonary valves and in pericardium before and after a detergent-based decellularization procedure. The fine structural characteristics of galactosaminoglycans chondroitin sulfate and dermatan sulfate were examined by FACE. Furthermore, the mechanical properties of decellularized pericardium and its propensity to be repopulated by in vitro seeded fibroblasts were investigated. Results show that galactosaminoglycans and hyaluronan are differently distributed between pericardium and valves and within heart valves themselves before and after decellularization. The distribution of glycosaminoglycans is also dependent from the vascular district and topographic localization. The decellularization protocol adopted resulted in a relevant but not selective depletion of galactosaminoglycans. As a whole, data suggest that both decellularized porcine heart valves and bovine pericardium represent promising materials bearing the potential for future development of tissue engineered heart valve scaffolds

Mechanical testing of pericardium for manufacturing prosthetic heart valves

Mammalian pericardia are currently used for the production of percutaneous prosthetic heart valves. The characteristics of biological tissues largely influence the durability of prosthetic devices used in the percutaneous approach and in traditional surgery, too. This paper reviews methodologies employed to assess and compare mechanical properties of pericardial patches from different mammalian species in order to identify the biomaterials adequate for manufacturing prosthetic heart valves

Native Bovine and Porcine Pericardia Respond to Load With Additive Recruitment of Collagen Fibers

Bovine and porcine pericardia are currently used for manufacturing prosthetic heart valves: their design has become an increasingly important area of investigation in parallel with progressively expanding indications for the transcutaneous approach to heart valves replacement. Before being cut and shaped, pericardial tissues are expected to be properly characterized. Actually, the mechanical assessment of these biomaterials lacks standardized protocols. In particular, the role of preconditioning for achieving a constant mechanical response of tissue samples is still controversial. In the present work, the mechanical response to uniaxial load of native bovine and porcine pericardia, with and without preconditioning was assessed; moreover, the mechanical behavior of pericardia was investigated and explained. It was demonstrated that: (i) pericardial tissue samples hold memory of the loading history but just within the extent of the deformation applied; (ii) the behavior of native bovine and porcine pericardia in response to load is explained by a mechanism based on the additive recruitment of collagen fibers; (iii) the current concept that plasticity is absent in pericardium has to be at least in part reconsidered

On assessing the accuracy of air pollution models exploiting a strategic sensors deployment

This paper presents a preliminary experiment done to identify potential problems and issues in setting up a testbed for air pollution measurement and modeling. Our final testbed, part of a joint research activity between the University of Bologna and the Macao Polytechnic Institute, will be composed of three lines of the air pollution sensors Canarin II and it will be used to produce spatio-temporal open data to test third-party air pollution models. Here, we present a preliminary experiment based on a single line of sensors, showing interesting insights into the actual open challenge of air pollution modeling techniques validation, taking into account the effects of air pollutant emissions sources, meteorology, atmospheric concentrations and urban vegetation

Endoplasmic reticulum/mitochondria calcium cross-talk

none9The interaction of mitochondria with the endoplasmic reticulum (ER) Ca2+ store plays a key role in allowing these organelles to rapidly and effectively respond to cellular Ca2+ signals. In this contribution, we will briefly discuss: (i) old and new concepts of mitochondrial Ca2+ homeostasis; (ii) the relationship between mitochondrial 3D structure and Ca2+ homeostasis; (iii) the modulation by cytoplasmic signalling pathways; and (iv) new data suggesting that mitochondria and ER Ca2+ channels are assembled in a macromolecular complex in which the inositol-1,4,5-trisphosphate receptor directly stimulates the mitochondrial Ca2+ uptake machinery.noneRomagnoli, Anna; Aguiari, Paola; De Stefani, Diego; Leo, Sara; Marchi, Saverio; Rimessi, Alessandro; Zecchini, Erika; Pinton, Paolo; Rizzuto, RosarioRomagnoli, Anna; Aguiari, Paola; DE STEFANI, Diego; Leo, Sara; Marchi, Saverio; Rimessi, Alessandro; Zecchini, Erika; Pinton, Paolo; Rizzuto, Rosari

Canarin II: Designing a smart e-bike eco-system

Mobility and ambient conditions are key factors in urban environments, affecting well-being and quality of life. In this context, sensors, smart mobility, networks, connectivity can play a significant and strategic role, being exploited with the aim of improving data and information available to public administration and to each citizen. In this way, they can be supported in having more sustainable and aware behaviours and in getting useful information and services, improving their daily activities. In this paper, we present a prototype of smart bike eco-system, designed with the aim of collecting, aggregating and sharing data about air pollution and about the urban environment, which can be exploited in a smart mobility context thanks to sensor and vehicular networks

Preservation strategies for decellularized pericardial scaffolds for off-the-shelf availability

Decellularized biological scaffolds hold great promise in cardiovascular surgery. In order to ensure off-the-shelf availability, routine use of decellularized scaffolds requires tissue banking. In this study, the suitability of cryopreservation, vitrification and freeze-drying for the preservation of decellularized bovine pericardial (DBP) scaffolds was evaluated. Cryopreservation was conducted using 10% DMSO and slow-rate freezing. Vitrification was performed using vitrification solution (VS83) and rapid cooling. Freeze-drying was done using a programmable freeze-dryer and sucrose as lyoprotectant. The impact of the preservation methods on the DBP extracellular matrix structure, integrity and composition was assessed using histology, biomechanical testing, spectroscopic and thermal analysis, and biochemistry. In addition, the cytocompatibility of the preserved scaffolds was also assessed. All preservation methods were found to be suitable to preserve the extracellular matrix structure and its components, with no apparent signs of collagen deterioration or denaturation, or loss of elastin and glycosaminoglycans. Biomechanical testing, however, showed that the cryopreserved DBP displayed a loss of extensibility compared to vitrified or freeze-dried scaffolds, which both displayed similar biomechanical behavior compared to non-preserved control scaffolds. In conclusion, cryopreservation altered the biomechanical behavior of the DBP scaffolds, which might lead to graft dysfunction in vivo. In contrast to cryopreservation and vitrification, freeze-drying is performed with non-toxic protective agents and does not require storage at ultra-low temperatures, thus allowing for a cost-effective and easy storage and transport. Due to these advantages, freeze-drying is a preferable method for the preservation of decellularized pericardium