title: Increased infarct wall thickness by a bio-inert material is insufficient to prevent negative left ventricular remodeling after myocardial infarction.
abstract: BACKGROUND
  Several injectable materials have been shown to preserve or improve cardiac function as well as prevent or slow left ventricular (LV) remodeling post-myocardial infarction (MI). However, it is unclear as to whether it is the structural support or the bioactivity of these polymers that lead to beneficial effects. Herein, we examine how passive structural enhancement of the LV wall by an increase in wall thickness affects cardiac function post-MI using a bio-inert, non-degradable synthetic polymer in an effort to better understand the mechanisms by which injectable materials affect LV remodeling.
  
  
  RESULTS
  Poly(ethylene glycol) (PEG) gels of storage modulus G' = 0.5±0.1 kPa were injected and polymerized in situ one week after total occlusion of the left coronary artery in female Sprague Dawley rats. The animals were imaged using magnetic resonance imaging (MRI) at 7±1 day(s) post-MI as a baseline and again post-injection 49±4 days after MI. Infarct wall thickness was statistically increased in PEG gel injected vs. control animals (p<0.01). However, animals in the polymer and control groups showed decreases in cardiac function in terms of end diastolic volume, end systolic volume and ejection fraction compared to baseline (p<0.01). The cellular response to injection was also similar in both groups.
  
  
  CONCLUSIONS
  The results of this study demonstrate that passive structural reinforcement alone was insufficient to prevent post-MI remodeling, suggesting that bioactivity and/or cell infiltration due to degradation of injectable materials are likely playing a key role in the preservation of cardiac function, thus providing a deeper understanding of the influencing properties of biomaterials necessary to prevent post-MI negative remodeling.
authors: Department of Bioengineering, University of California San Diego, La Jolla, California, United States of America.
authors: Aboli A
authors: AA
authors: Rane
authors: Joyce S
authors: JS
authors: Chuang
authors: Amul
authors: A
authors: Shah
authors: Diane P
authors: DP
authors: Hu
authors: Nancy D
authors: ND
authors: Dalton
authors: Yusu
authors: Y
authors: Gu
authors: Kirk L
authors: KL
authors: Peterson
authors: Jeffrey H
authors: JH
authors: Omens
authors: Karen L
authors: KL
authors: Christman
mesh_terms: D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D001672:Biocompatible Materials / Q000494:pharmacology*; D005260:Female; D006334:Heart Function Tests; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology; D021621:Imaging, Three-Dimensional; D007249:Inflammation / Q000150:complications / Q000473:pathology; D007267:Injections; D008422:Materials Testing; D055595:Mechanical Phenomena / Q000187:drug effects; D009203:Myocardial Infarction / Q000150:complications / Q000473:pathology* / Q000503:physiopathology*; D011092:Polyethylene Glycols / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020257:Ventricular Remodeling / Q000187:drug effects*
chemical_list: D001672:Biocompatible Materials; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D011092:Polyethylene Glycols