title: Physical properties of poly(N-isopropylacrylamide) hydrogel promote its effects on cardiac protection after myocardial infarction.
abstract: OBJECTIVE
  Studies have demonstrated the protective effects of biomaterials against myocardial infarction (MI), but the relationship between their physical characteristics and their function is incompletely understood. This study investigated such relationships for a hydrogel preparation.
  
  
  METHODS
  Two types of poly(N-isopropylacrylamide) (PNIPAAm) hydrogel with different degradation times (Gel A and Gel B) were synthesized. In vivo hydrogel formation and maintenance were observed and confirmed in mice. The solutions were also injected into the infarct area immediately  after MI induction in rats.
  
  
  RESULTS
  PNIPAAm hydrogel exhibited a three-dimensional structure resembling native extracellular matrix (ECM). Compared with phosphate-buffered saline, Gel A and Gel B increased contractility of isolated infarcted myocardium, reduced collagen deposition, increased  neovascularization, inhibited left ventricle expansion and improved cardiac function. Myocardial contractility was greater with Gel B than with Gel A.
  
  
  CONCLUSIONS
  Intramyocardial injection of PNIPAAm hydrogel provides structural support and some functional repair of damaged ECM, suggesting  that it might be useful for cardiac tissue engineering.
authors: Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.
authors: S
authors: S
authors: Ren
authors: X
authors: X
authors: Jiang
authors: Z
authors: Z
authors: Li
authors: Y
authors: Y
authors: Wen
authors: D
authors: D
authors: Chen
authors: X
authors: X
authors: Li
authors: X
authors: X
authors: Zhang
authors: R
authors: R
authors: Zhuo
authors: H
authors: H
authors: Chu
mesh_terms: D000180:Acrylic Resins / Q000627:therapeutic use*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000627:therapeutic use; D002316:Cardiotonic Agents / Q000627:therapeutic use*; D005109:Extracellular Matrix; D006334:Heart Function Tests; D020100:Hydrogels / Q000737:chemistry / Q000627:therapeutic use*; D008422:Materials Testing; D051379:Mice; D009200:Myocardial Contraction / Q000187:drug effects*; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000517:prevention & control; D018919:Neovascularization, Physiologic / Q000187:drug effects; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D023822:Tissue Engineering; D020257:Ventricular Remodeling / Q000187:drug effects
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; D002316:Cardiotonic Agents; D020100:Hydrogels; C052970:poly-N-isopropylacrylamide