Decellularized materials derived from TSP2-KO mice promote enhanced neovascularization and integration in diabetic wounds

Abstract

Decellularized biologic scaffolds are gaining popularity over synthetic biomaterials as naturally derived materials capable of promoting improved healing. Nevertheless, the most widely used biologic material - acellular dermal matrix (ADM) - exhibits slow repopulation and remodeling, which prevents integration. Additionally, engineering control of these materials is limited because they require a natural source for their production. In the current report, we demonstrate the feasibility of using genetically engineered animals to create decellularized biologic scaffolds with favorable extracellular matrix (ECM) properties. Specifically, we utilized skin from thrombospondin (TSP)-2 KO mice to derive various decellularized products. Scanning electron microscopy and mechanical testing showed that TSP-2 KO ADM exhibited an altered structure and a reduction in elastic modulus and ultimate tensile strength, respectively. When a powdered form of KO ADM was implanted subcutaneously, it was able to promote enhanced vascularization over WT. Additionally, when implanted subcutaneously, intact slabs of KO ADM were populated by higher number of host cells when compared to WT. In vitro studies confirmed the promigratory properties of KO ADM. Specifically, degradation products released by pepsin digestion of KO ADM induced greater cell migration than WT. Moreover, cell-derived ECM from TSP-2 null fibroblasts was more permissive to fibroblast migration. Finally, ADMs were implanted in a diabetic wound model to examine their ability to accelerate wound healing. KO ADM exhibited enhanced remodeling and vascular maturation, indicative of efficient integration. Overall, we demonstrate that genetic manipulation enables engineered ECM-based materials with increased regenerative potential.

Elevated Thrombospondin 2 Contributes to Delayed Wound Healing in Diabetes

“…Our work shows that overexpression of TSP2 in diabetes contributes to compromised healing through its impact on cell migration. Analysis of wound angiogenesis at day 10, when TSP2 KO wounds differ most significantly from WT wounds (6), revealed more aSMA-positive vessels in DKO wounds, indicative of enhanced blood vessel maturation and consistent with studies of db/db wounds treated with TSP2 KO decellularized skin slabs (13). Accelerated vessel maturation in DKO wounds likely results from the influence of TSP2 on migration of fibroblasts, which facilitate repair and migration of other cell types, into the wound at day 7.…”

“…Full-thickness, nonsplinted excisional wounds were generated as previously described (6,(12)(13)(14). Briefly, mice were anesthetized and depilated, and two 6-mm wounds were created with a biopsy punch (Acuderm) and left uncovered.…”

“…Healing in DKO mice was evaluated through a fullthickness excisional wound model (12,13). DKO mice exhibited improved healing, with more rapid reduction of wound size (Fig.…”

Therapeutic strategies for skin regeneration based on biomedical substitutes

“…These materials have proven to be advantageous since they are made of biomolecules similarly found in natural tissues and can be degraded and cleared by the host's native physiological processes. Moreover, complete de‐cellularization of skin tissue to create ECM based matrix scaffolds for skin regeneration has been developed . Lately, a growing body of studies has highlighted the relevance of the combination of different biomaterials to create products with enhanced properties.…”

“…Moreover, complete de-cellularization of skin tissue to create ECM based matrix scaffolds for skin regeneration has been developed. 76 Lately, a growing body of studies has highlighted the relevance of the combination of different biomaterials to create products with enhanced properties. For example, to generate a full-thickness skin substitute, fibrin and agarose were mixed with fibroblasts and subsequently seeded with keratinocytes.…”