Figure 1.
Typical mechanical spectra for a hydrogel formed by crosslinking of 4-arm PEG-ASG (100 mg/ml) and trilysine (1 mg/ml).
Figure 2.
Histological assessment of polymer and saline injections 7 weeks after MI. Representative slides stained with H&E: (A) PEG hydrogel (G′ = 0.5 kPa) injected in infarct region and (B) saline injected in infarct region. (C) Infarct wall thickness at 7 weeks post-MI. Wall thinning was prevented in the PEG injected group compared to the control. (*p<0.01, PEG: n = 7, saline: n = 8 ) Photomicrographs are taken at 10Х and scale bars are 1 mm. PEG area outlined with dotted line and demarcated by an asterisk (*).
Figure 3.
Comparison of cardiac function baseline (1 week post-MI, pre-injection) and post-treatment (7 weeks post-MI) in PEG (0.5 kPa) injected and saline injected groups. (A) Ejection fraction. (B) End diastolic volume. (C) End systolic volume. Statistical significance determined using paired two-tailed t-test between pre and post-injection groups. (*p<0.01 PEG compared to baseline, § p<0.01 saline compared to baseline, PEG: n = 6, saline: n = 6).
Figure 4.
Finite element representation of the LV pre and post-injection in both PEG and saline injected groups. Arrow denotes region of infarction. Infarct wall thickening is seen in the PEG injected heart while infarct wall thinning is depicted in the saline injected heart compared to baseline. Also note the dilation of LV lumen pre and post-injection in both groups.
Figure 5.
Inflammatory response in polymer and saline injected hearts 7 weeks after MI. (A) PEG injected heart (inset shows high magnification image of PEG region showing no cell infiltration in the polymer, scale bar 20 µm) (B) saline injected heart. Scale bars are 100 µm. PEG area is demarcated by an asterisk (*). CD68 stained macrophages in (C) PEG injected heart (D) saline injected heart. PEG area outlined with a dotted line. Scale bars are 20 µm.
Figure 6.
Arteriole density assessment in polymer and saline injected hearts 7 weeks after MI. (A, B) Representative slides with staining for smooth muscle actin. (A) Arterioles in infarct region of PEG injected animals. PEG area outlined with dotted line and demarcated by an asterisk (*). (B) Arterioles in infarct region of saline injected animals. Scale bars are 100 µm. (C) Arteriole density (vessel diameter between 10 µm and 100 µm) at 7 weeks post-MI. ( p = 0.80, PEG: n = 6, saline: n = 8 ).