Exploring the match between the degradation of the ECM-based composites and tissue remodeling in a full-thickness abdominal wall defect model

The repair of abdominal wall defects is currently a clinical challenge. A naturally derived extracellular matrix (ECM) such as small intestine submucosa (SIS) has received great attention in abdominal wall defect repair because of its remarkable bioactivity, biodegradability and tissue regeneration. The match between material degradation and tissue remodeling is very important for the realization of ideal repair effectiveness. In this study, a near-infrared (NIR) fluorescent dye Cy5.5 NHS ester was used to label ECM-based (ECMB) composites consisting of SIS and chitosan/elastin electrospun nanofibers for monitoring material degradation. The tissue remodeling in the ECMB composites for a full-thickness abdominal wall defect repair was systematically investigated by a series of tests including wall thickness measurement, muscle regeneration analysis and angiogenesis assessment. The main findings were: (1) real-time and noninvasive degradation monitoring of the ECMB composites until complete degradation could be realized by chemical conjugation with a Cy5.5 NHS ester. (2) In a full-thickness abdominal wall defect model, the explant thickness could be used as an intuitional indicator for evaluating the tissue remodeling efficiency in the ECMB composites, and the accuracy of this indicator was verified by various examinations including collagen deposition, angiogenesis, and muscle regeneration. The present study could provide new insight into evaluating tissue repair effectiveness of the ECMB composites.