title: Bacterial nanocellulose as a new patch material for closure of ventricular septal defects in a pig model.
abstract: OBJECTIVE
  Current materials for closure of cardiac defects such as ventricular septal defects (VSDs) are associated with compliance mismatch and a chronic inflammatory response. Bacterial nanocellulose (BNC) is a non-degradable biomaterial with promising properties such as high mechanical strength, favourable elasticity and a negligible inflammatory reaction. The aim of this study was the evaluation of a BNC patch for VSD closure and the investigation of its in vivo biocompatibility in a chronic pig model.
  
  
  METHODS
  Young's modulus and tensile strength of BNC patches were determined before and after blood exposure. Muscular VSDs were created and closed with a BNC patch on the beating heart in an in vivo pig model. Hearts were explanted after 7, 30 or 90 days. Macropathology, histology and immunohistochemistry were performed.
  
  
  RESULTS
  Young's modulus and tensile strength of the BNC patch decreased after blood contact from 6.3 ± 1.9 to 3.86 ± 2.2 MPa (P < 0.01) and 0.33 ± 0.06 to 0.26 ± 0.06 MPa (P < 0.01), respectively, indicating the development of higher elasticity. Muscular VSDs were closed with a BNC patch without residual shunting. After 90 days, a mild chronic inflammatory reaction was present. Moreover, there was reduced tissue overgrowth in comparison with polyester. Proceeding cellular organization characterized by fibromuscular cells, production of extracellular matrix, neoangiogenesis and complete neoendothelialization were found. There were no signs of thrombogenicity.
  
  
  CONCLUSIONS
  BNC patches can close VSDs with good mid-term results and its biocompatibility can be considered as satisfactory. Its elasticity increases in the presence of blood, which might be advantageous. Therefore, it has potential to be used as an alternative patch material in congenital heart disease.
authors: Department of Pediatric Cardiology and Intensive Care Medicine, Ludwig-Maximilians-University, Munich, Germany Department of Congenital Heart Defects and Pediatric Cardiology, Heart Center, University of Freiburg, Freiburg, Germany nora.lang@universitaets-herzzentrum.de nora.f.lang80@gmail.com.
authors: Nora
authors: N
authors: Lang
authors: Department of Pediatric Cardiology and Intensive Care Medicine, Ludwig-Maximilians-University, Munich, Germany.
authors: Elena
authors: E
authors: Merkel
authors: Department of Pediatric Cardiology and Intensive Care Medicine, Ludwig-Maximilians-University, Munich, Germany.
authors: Franziska
authors: F
authors: Fuchs
authors: Transfer Group Polymet e.V, Jena, Germany.
authors: Dieter
authors: D
authors: Schumann
authors: Transfer Group Polymet e.V, Jena, Germany.
authors: Dieter
authors: D
authors: Klemm
authors: Transfer Group Polymet e.V, Jena, Germany.
authors: Friederike
authors: F
authors: Kramer
authors: Department of Orthopedic Surgery, Ludwig-Maximilians-University, Munich, Germany.
authors: Susanne
authors: S
authors: Mayer-Wagner
authors: Department of Orthopedic Surgery, Ludwig-Maximilians-University, Munich, Germany.
authors: Christian
authors: C
authors: Schroeder
authors: Kardiozentrum, La Paz, Bolivia.
authors: Franz
authors: F
authors: Freudenthal
authors: Department of Pediatric Cardiology and Intensive Care Medicine, Ludwig-Maximilians-University, Munich, Germany.
authors: Heinrich
authors: H
authors: Netz
authors: Department of Pediatric Cardiology and Intensive Care Medicine, Ludwig-Maximilians-University, Munich, Germany.
authors: Rainer
authors: R
authors: Kozlik-Feldmann
authors: Department of Pediatric Cardiology and Intensive Care Medicine, Georg-August-University Göttingen, Göttingen, Germany.
authors: Matthias
authors: M
authors: Sigler
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000627:therapeutic use*; D006348:Cardiac Surgical Procedures / Q000295:instrumentation*; D002482:Cellulose / Q000096:biosynthesis / Q000737:chemistry / Q000627:therapeutic use*; D055119:Elastic Modulus; D041822:Gluconacetobacter xylinus / Q000378:metabolism; D006345:Heart Septal Defects, Ventricular / Q000601:surgery*; D008422:Materials Testing; D009206:Myocardium / Q000737:chemistry / Q000473:pathology; D013552:Swine; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D002482:Cellulose
keywords: Biocompatibility; Biomaterial; Patch material; Ventricular septal defects