Background: Extracellular matrix derived from porcine small
intestinal submucosa is used for the repair of musculotendinous tissues.
Preclinical evaluation and clinical use have suggested that small intestinal
submucosa extracellular matrix degrades rapidly after implantation and can be
replaced by host tissue that is functionally and histologically similar to the
Methods: The present study analyzed the temporal degradation of a
ten-layer multilaminate device of small intestinal submucosa extracellular
matrix used for the repair of canine Achilles tendon and examined the
corresponding histological appearance of the remodeled tissue during the
course of scaffold degradation. Devices were fabricated from small intestinal
submucosa extracellular matrix labeled with 14C. The amount of
14C remaining in the remodeled graft was measured by liquid
scintillation counting at three, seven, fourteen, twenty-eight, sixty, and
ninety days after surgery. Blood, urine, feces, and other parenchymal tissues
were also harvested to determine the fate of scaffold degradation products.
Tissue specimens were prepared for routine histological analysis to examine
the morphology of the remodeled graft at each time-point.
Results: The small intestinal submucosa extracellular matrix graft
degraded rapidly, with approximately 60% of the mass lost by one month after
surgery, and the graft was completely resorbed by three months after surgery.
The graft supported rapid cellular infiltration and host tissue ingrowth. By
ninety days after surgery, the remodeled small intestinal submucosa
extracellular matrix consisted of a dense collagenous tissue with
organization, cellularity, and vascularity similar to that of normal
Conclusions: Small intestinal submucosa extracellular matrix is
rapidly degraded after implantation for the repair of a musculotendinous
tissue in this canine Achilles tendon repair model and is replaced by the
deposition and organization of host tissue that is histologically similar to
that of normal tissue.
Clinical Relevance: The present study provides insight into the
degradation and remodeling of extracellular matrix derived from porcine small
intestinal submucosa, a biologic scaffold that has been used clinically for