title: Targeted myocardial microinjections of a biocomposite material reduces infarct expansion in pigs.
abstract: BACKGROUND
  Left ventricular (LV) remodeling after myocardial infarction (MI) commonly causes infarct expansion (IE). This study sought to interrupt IE through microinjections of a biocompatible composite material into the post-MI myocardium.
  
  
  METHODS
  MI was created in 21 pigs (coronary ligation). Radiopaque markers (2-mm diameter) were placed for IE (fluoroscopy). Pigs were randomized for microinjections (25 injections; 2- x 2-cm array; 200 microL/injection) at 7 days post-MI of a fibrin-alginate composite (Fib-Alg; fibrinogen, fibronectin, factor XIII, gelatin-grafted alginate, thrombin; n = 11) or saline (n = 10).
  
  
  RESULTS
  At 7 days after injection (14 days post-MI), LV posterior wall thickness was higher in the Fib-Alg group than in the saline group (1.07 +/- 0.11 vs 0.69 +/- 0.07 cm, respectively, p = 0.002). At 28 days post-MI, the area within the markers (IE) increased from baseline (1 cm2) in the saline (1.71 +/- 0.13 cm2, p = 0.010) and Fib-Alg groups (1.44 +/- 0.23 cm2, p < 0.001). However, the change in IE at 21 and 28 days post-MI was reduced in the Fib-Alg group (p=0.043 and p=0.019). Total collagen content within the MI region was similar in the saline and Fib-Alg groups (12.8 +/- 1.7 and 11.6 +/- 1.5 microg/mg, respectively, p = NS). However, extractable collagen, indicative of solubility, was lower in the Fib-Alg group than the saline group (59.1 +/- 3.5 vs 71.0 +/- 6.1 microg/mL, p = 0.020).
  
  
  CONCLUSIONS
  Targeted myocardial microinjection of the biocomposite attenuated the post-MI decrease in LV wall thickness and infarct expansion. Thus, intraoperative microinjections of biocompatible material may provide a novel approach for interrupting post-MI LV remodeling.
authors.affiliation: Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, South Carolina 29425, USA. mukherr@musc.edu
authors.forename: Rupak
authors.initials: R
authors.lastname: Mukherjee
authors.forename: Juozas A
authors.initials: JA
authors.lastname: Zavadzkas
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Saunders
authors.forename: Julie E
authors.initials: JE
authors.lastname: McLean
authors.forename: Laura B
authors.initials: LB
authors.lastname: Jeffords
authors.forename: Christy
authors.initials: C
authors.lastname: Beck
authors.forename: Robert E
authors.initials: RE
authors.lastname: Stroud
authors.forename: Allyson M
authors.initials: AM
authors.lastname: Leone
authors.forename: Christine N
authors.initials: CN
authors.lastname: Koval
authors.forename: William T
authors.initials: WT
authors.lastname: Rivers
authors.forename: Shubhayu
authors.initials: S
authors.lastname: Basu
authors.forename: Alexander
authors.initials: A
authors.lastname: Sheehy
authors.forename: Gene
authors.initials: G
authors.lastname: Michal
authors.forename: Francis G
authors.initials: FG
authors.lastname: Spinale
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000008:administration & dosage*; D004195:Disease Models, Animal; D005260:Female; D015552:Injections, Intralesional; D008297:Male; D008845:Microinjections; D009203:Myocardial Infarction / Q000473:pathology / Q000503:physiopathology* / Q000628:therapy*; D011336:Probability; D011897:Random Allocation; D012016:Reference Values; D012680:Sensitivity and Specificity; D013552:Swine; D020257:Ventricular Remodeling / Q000502:physiology
chemical_list: D001672:Biocompatible Materials