Transforming growth factor‐β1 in a sterilized tissue derived from the pig small intestine submucosa

Abstract

The extracellular matrices of connective tissues contain growth factors such as transforming growth factor (TGF)-beta1. The possibility arises, therefore, that animal connective tissues that have been excised and rendered acellular in the sterilization, lyophilization, and other preparative processes for human use may still retain active growth factors that could contribute to the clinical efficacy of the product. We therefore analyzed 4M guanidine HCl extracts of a sterilized, acellular matrix, Oasis Wound Matrix, for the presence of TGF-beta1 by a sandwich enzyme-linked immunosorbent assay using the soluble type II receptor for TGF-beta to capture the growth factor, and for biological activity by testing the capacity of the extracts to inhibit 3[H]thymidine incorporation into Mv1Lu cells (mink lung epithelial cells). The enzyme-linked immunosorbent assay determined that TGF-beta1 was present at a concentration of 710.9 +/- 157.7 pg/g dry weight of tissue in Oasis and 768.1 +/- 182.1 pg/g dry weight of tissue in SIS (porcine small intestinal submucosa), the disinfected precursor of Oasis. The growth inhibition assays demonstrated that the Oasis extracts inhibited the proliferation of Mv1Lu cells in culture, consistent with the TGF-beta1 in the material having biological activity. Most of the TGF-beta1 survives the sterilization and lyophilization processes in the preparation of the Oasis Wound Matrix, and is functional in its ability to bind to its receptor and, apparently, in its capacity to inhibit growth.

Macrophage Participation in the Degradation and Remodeling of Extracellular Matrix Scaffolds

“…21,37,38 Degradationdependent events such as the release of constituent growth factors, the production and release of matricryptic peptides, and the recruitment of host progenitor cells and stem cells contribute to the well-documented dynamic histomorphologic changes that characterize the host response to such scaffold materials during this early postoperative period. 3,4,6,9,12,[39][40][41][42][43] It is logical to speculate, based upon the results of the present study, that blood-derived mononuclear macrophages are at least important, if not essential, mediators of these degradation-dependent events. It is therefore reasonable to conclude that the degradation of an ECM scaffold is beneficial and necessary to tissue remodeling efforts.…”

Comparing the endothelialisation of extracellular matrix bioscaffolds with coated synthetic vascular graft materials

“…These growth factors are bound to ECM proteoglycans and glycosaminoglycans, which protect them from degradation and enhance their presentation to occupying cells [28]. Importantly these growth factors have been shown to survive the production and sterilisation steps in preparing ECM scaffolds for medical use [29,30]. In the past, researchers have struggled to integrate purified forms of growth factors into synthetic scaffolds [31].…”

Future prospects for tissue engineered lung transplantation

“…16 Such methods have been shown to eliminate all intact cells (i.e., decellularize) and degrade any nucleic acid remnants to less than 200 base pairs with less than 50 ng of dsDNA per 1 mg dry weight of the extracellular matrix scaffold while leaving intact the constituent growth factors such as fibroblast growth factor (FGF), epidermal growth factor (EGF), hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF), bone morphogenic protein (BMP) and vascular endothelial growth factor (VEGF). 17,18 ECM scaffolds are currently used for arterial grafts, heart valves, urinary tract reconstitution, skin reconstruction, dura mater grafts following intracranial surgery, and orthopedic applications. Some of the scaffolds are available commercially including: porcine heart valve (Hancock II®), bovine pericardium heart valve (PERIMOUNT Magna®), human heart valve (Synegraft®), human dermis (Alloderm®), porcine small intestinal scaffold (OaSIS ® ), and decellularized bone (Allograft c-ring ® ).…”