Acellular collagen sponge induced re-vascularization

Objectives: Evaluation the effect of extracellular matrix (ECM) derived from Human bone marrow Mesenchymal Stem Cell (hBM-MSC) on re-vascularization for bone tissue engineering applications.
Methods: Collagen sponge is a 3D spongious scaffold fabricate from cross linked type I collagen extracted and purified from porcine tendons. hBM-MSC were cultured on collagen sponge in osteogenic induction media for 21 days. The sponge was subjected to the acellularization process and lyophilized. The acellularized sponge analyzed by histology and confocal images. Scaffolds (collagen & acellularized collagen sponges) were subcutaneously transplanted for 14 days in nude mice. Perfusion and vascularization were assessed by: 1. injection of Dextran into the tail vein and analysis of the functional vessel from confocal images 2. Ultrasound determination –contrast agent (microbubles) were injected into the tail vein

Results: Acellular spnge was evaluated using histology analysis. Hematoxylin Eosin (H&E) staining revealed that acellularization protocol efficiently eliminated all living cells while leaving the ECM components intact .
Confocal microscopy images of functional vessel density derived from the acellularized sponge was higher compare to those seen in the untreated collagen sponge images. Ultrasonigraphic evaluation showed higher perfusion of acellularized scaffold,14 days postimplantation, compare to untreated collagen sponge which was expressed by number of orange pixels within the scaffold immediately after the disruption pulse of the microbubbles.

Conclusions: Using mouse subcutaneous transplantation model hBM-MSC derived ECM scaffold has demonstrated higher density of functional vessel. This increased re-vascularization potential may indicate higher potential of bone generation for tissue engineering