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VALENTINA DI FELICE

The role of biomaterials in the direction of cardiac stem cells properties, differentiation and extracellular matrix interactions in cardiac tissue engineering

  • Autori: DI FELICE, V.; Serradifalco, C.; Rizzuto, L.; DE LUCA, A.; MARINO GAMMAZZA, A.; Di Marco, P.; Cassata, G.; Puleio, R.; Verin, L.; Motta, A.; Guercio, A.; Zummo, G.
  • Anno di pubblicazione: 2011
  • Tipologia: Altro
  • Parole Chiave: cardiac stem cells, scaffolds, tissue engineering
  • OA Link: http://hdl.handle.net/10447/55520

Abstract

Introduction: One of the main problems in the rapid translation of preclinical cell‐based therapy to restore damaged myocardium is to find the best delivery route and the best time of cell injection into the myocardium. Intramyocardial injection of stem cells is by far the mostused delivery technique in preclinical studies. Three‐dimensional scaffolds may be used to deliver a limited number of stem cells in their undifferentiated state, but many biomaterials may cause a foreign body reaction on their own. We have recently demonstrated that c‐Kit positive cardiac progenitor cells are able to organize themselves into a tissue‐like cell mass in collagen I three‐dimensional cultures within 72h in 5% horse serum and that inside an Open Pore Poly‐lactic acid scaffold, commercially available, these cells can create an organized elementary myocardium. Hypothesis: We assessed the hypothesis that poly‐lactic and fibroin scaffolds, designed to deliver cardiac progenitor cells in the infarcted region of the heart, may induce a better differentiation into cardiomyocytes. Methods: For the synthesis of PDLLA scaffolds, the Poly (D,L lactic acid) (RESOMER® 207, MW = 252 kDa) polimer were used (6.7%) in Dicloromethane/Dimetilformamide (DCM/DMF) 70/30 (v/v). The three‐dimensional structure was obtained by salt‐leaching, using NaCl crystals as porosity agent (NaCl < 224 μm and <150 μm). For the synthesis of fibroin scaffolds, degummed silk fibres were dried and dissolved into 9.3 m LiBr water solution (20% w/v) at 65°C for 3h. Scaffolds with different porosities, pore size, and properties were made by freeze‐drying and salt‐leaching. Silk fibroin nets were created from silk powder after freeze‐drying. A net was made by electrospinning a solution containing 10% wt of fibroin solution in formic acid. To test the foreign body reaction scaffolds alone or embedded with collagen I and cardiac progenitor cells were implanted in the subcutaneous dorsal region of athymic Nude‐Foxn1nu mice for 45 days. Results: Cardiac progenitor cells were obtained by collagenase type II digestion of beating adult rat hearts, and tested after each preparation for the expression of c‐Kit, MDR‐1 and Sca‐1 by flow cytometry. These cells were able to partially differentiate into cardiomyocytes in vitro into all the synthesized scaffolds in a M‐199 medium supplemented with 20% FBS within 21 days. The degree of differentiation and the expression of extracellular matrix and integrin proteins depended on the type of scaffold used. In vivo, all the used scaffolds induced a foreign body reaction, apart from fibroin nets. Cells implanted within scaffolds were rapidly degraded by the foreign body reaction. Cardiac stem cells alone implanted in nude mice were also degraded by a cell‐mediated immune response. Conclusions: Scaffolds are useful devices to deliver cardiac stem cells in the site of implantation, but more research is needed to find non‐reactive biomaterials.