Histopathology:
Histology was performed on the capsular tissue of the CIED with CanGaroo ECM Envelope and CIED without envelope groups to quantify and score the tissue response. H&E and trichrome slides showed normal collagen formation and organization in the connective tissue, which was similar between the groups (Figure 3 ). The use of CanGaroo ECM Envelopes generated a lower average capsule thickness compared to CIEDs without envelopes with a mean of 349 ± 165µm (mean ± SD) versus 417 ± 152µm at 13 weeks and a mean of 427 ± 141µm versus 439 ± 91µm at 26 weeks. High standard deviation was seen in these measurements due to animal-to-animal variation in capsule formation.