title: Combining experimental and mathematical modeling to reveal mechanisms of macrophage-dependent left ventricular remodeling.
abstract: BACKGROUND
  Progressive remodeling of the left ventricle (LV) following myocardial infarction (MI) can lead to congestive heart failure, but the underlying initiation factors remain poorly defined. The objective of this study, accordingly, was to determine the key factors and elucidate the regulatory mechanisms of LV remodeling using integrated computational and experimental approaches.
  
  
  RESULTS
  By examining the extracellular matrix (ECM) gene expression and plasma analyte levels in C57/BL6J mice LV post-MI and ECM gene responses to transforming growth factor (TGF-β₁) in cultured cardiac fibroblasts, we found that key factors in LV remodeling included macrophages, fibroblasts, transforming growth factor-β₁, matrix metalloproteinase-9 (MMP-9), and specific collagen subtypes. We established a mathematical model to study LV remodeling post-MI by quantifying the dynamic balance between ECM construction and destruction. The mathematical model incorporated the key factors and demonstrated that TGF-β₁ stimuli and MMP-9 interventions with different strengths and intervention times lead to different LV remodeling outcomes. The predictions of the mathematical model fell within the range of experimental measurements for these interventions, providing validation for the model.
  
  
  CONCLUSIONS
  In conclusion, our results demonstrated that the balance between ECM synthesis and degradation, controlled by interactions of specific key factors, determines the LV remodeling outcomes. Our mathematical model, based on the balance between ECM construction and destruction, provides a useful tool for studying the regulatory mechanisms and for predicting LV remodeling outcomes.
authors.affiliation: Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, USA. yufang.jin@utsa.edu
authors.forename: Yu-Fang
authors.initials: YF
authors.lastname: Jin
authors.forename: Hai-Chao
authors.initials: HC
authors.lastname: Han
authors.forename: Jamie
authors.initials: J
authors.lastname: Berger
authors.forename: Qiuxia
authors.initials: Q
authors.lastname: Dai
authors.forename: Merry L
authors.initials: ML
authors.lastname: Lindsey
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D019295:Computational Biology / Q000379:methods; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology; D006333:Heart Failure / Q000503:physiopathology; D006801:Humans; D008264:Macrophages / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D008962:Models, Theoretical; D009203:Myocardial Infarction / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D049490:Systems Biology / Q000379:methods; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D016896:Treatment Outcome; D020257:Ventricular Remodeling / Q000502:physiology*
chemical_list: D053773:Transforming Growth Factor beta1