Fundamentals of Extracellular Matrix Biomaterial Assimilation: Effect of Suture Type on Attachment Strength and Cell Repopulation

The clinical results with extracellular matrix biomaterials are confounded by expectations of material response based on years of experience with permanent or degradable synthetic polymers. However, the remodeling or assimilation of extracellular matrix biomaterials is dictated by cell-mediated processes rather than fibrous encapsulation or hydrolytic degradation. Previously, we found that tissue adherence and revascularization were dictated by proximity with de-epithelialized host tissue. We now investigate the effects of polymer and fixation type on attachment strength and rate of cell repopulation in an intra-abdominal implant model. METHODS: An intra-abdominal implant model in rats was used to probe assimilation properties at 4 weeks and 12 weeks with permanent and degradable suture types as well a combination of suture and biologic attachment (mesothelial abrasion). The mechanical strength of the attachment was measured by peel testing and the repopulation by automated cell counting of histologic sections. RESULTS: The intensity of the biologic response was greater with degradable polymers than permanent polypropylene. Tissue attachment strength ranged from 2 to 15 N but changed in elasticity with time. The magnitude and distribution of cell repopulation was highly variable by suture type but ultimately did not affect the long-term strength of the soft tissue attachment. CONCLUSIONS: The tissue approximating polymer sutures were stretchy and of similar strength regardless of degradation rate or polymer type. The strongest attachment, most rapid repopulation of the deep matrix regions, and most uniform distribution of cells were found with the addition of biologic attachment.