Bioengineering vascularized tissue constructs using an injectable cell-laden enzymatically crosslinked collagen hydrogel derived from dermal extracellular matrix

Abstract

Tissue engineering promises to restore or replace diseased or damaged tissue by creating functional and transplantable artificial tissues. The development of artificial tissues with large dimensions that exceed the diffusion limitation will require nutrients and oxygen to be delivered via perfusion instead of diffusion alone over a short time period. One approach to perfusion is to vascularize engineered tissues, creating a de novo three-dimensional (3D) microvascular network within the tissue construct. This significantly shortens the time of in vivo anastomosis, perfusion and graft integration with the host. In this study, we aimed to develop injectable allogeneic collagen-phenolic hydroxyl (collagen-Ph) hydrogels that are capable of controlling a wide range of physicochemical properties, including stiffness, water absorption and degradability. We tested whether collagen-Ph hydrogels could support the formation of vascularized engineered tissue graft by human blood-derived endothelial colony-forming cells (ECFCs) and bone marrow-derived mesenchymal stem cells (MSC) in vivo. First, we studied the growth of adherent ECFCs and MSCs on or in the hydrogels. To examine the potential formation of functional vascular networks in vivo, a liquid pre-polymer solution of collagen-Ph containing human ECFCs and MSCs, horseradish peroxidase and hydrogen peroxide was injected into the subcutaneous space or abdominal muscle defect of an immunodeficient mouse before gelation, to form a 3D cell-laden polymerized construct. These results showed that extensive human ECFC-lined vascular networks can be generated within 7 days, the engineered vascular density inside collagen-Ph hydrogel constructs can be manipulated through refinable mechanical properties and proteolytic degradability, and these networks can form functional anastomoses with the existing vasculature to further support the survival of host muscle tissues. Finally, optimized conditions of the cell-laden collagen-Ph hydrogel resulted in not only improving the long-term differentiation of transplanted MSCs into mineralized osteoblasts, but the collagen-Ph hydrogel also improved an increased of adipocytes within the vascularized bioengineered tissue in a mouse after 1 month of implantation.

Biodegradable cell‐laden starch foams for the rapid fabrication of 3D tissue constructs and the application in neural tissue engineering

“…For tissue engineering application of large‐sized tissue‐like constructs, appropriate levels of oxygen and nutrients are needed to ensure cell survival. Otherwise, decrease in the cell viability can finally cause the failure of tissue regeneration or the necrosis of tissues . Porous 3D biomaterials for cell encapsulation have been developed to enhance the delivery of nutrients.…”

“…Cell-laden hydrogels can be assembled into constructs mimicking natural tissue structures or directly injected into injured sites to fill the tissue defect with irregular shapes. 10,11 In neural tissue engineering, researchers have developed a number of hydrogels (e.g., alginate, 12 collagen, 13 gelatin, 9 and self-assembling peptides 14 ) to encapsulate and release different types of cells (e.g., neural stem cells, 14 mesenchymal stem cells, 15 olfactory ensheathing cells, 16 and Schwann cells 17 ). Cell-laden hydrogels can be injected to the injury epicenter to fill the cavity or combined with nerve conduit to bridge the lesion gap, resulting in axon regeneration and functional recovery.…”

Therapeutic strategies for skin regeneration based on biomedical substitutes

“…Many types of cells are being administered via subcutaneous injection within different kinds of solutions composed of hyaluronic acid, PRP, collagen, chitosan, poly(ethylene glycol)‐poly( l ‐alanine), ECM or methylcellulose, among others . Moreover, cells can be applied mixed with injectable hydrogels that provide a scaffold for in situ tissue regrowth and regeneration, allowing surgeons to fill complex shapes with a minimal invasive procedure .…”

“…Many types of cells are being administered via subcutaneous injection within different kinds of solutions composed of hyaluronic acid, PRP, collagen, chitosan, poly(ethylene glycol)poly(L-alanine), ECM or methylcellulose, among others. 50,[55][56][57][58][59] Moreover, cells can be applied mixed with injectable hydrogels that provide a scaffold for in situ tissue regrowth and regeneration, allowing surgeons to fill complex shapes with a minimal invasive procedure. 60,61 Several biomaterials have been employed for developing injectable hydrogels to mimic the biological cues of native ECM, however, they cannot reproduce the complex functions of natural ECM.…”

Role of Biological Scaffolds, Hydro Gels and Stem Cells in Tissue Regeneration Therapy

“…This significantly shortens the time of in vivo anastomosis, perfusion and graft integration with the host. 59 For decellularization various combinations of physical, chemical, and enzymatic treatments are carefully given to isolate ECM scaffold. These treatments help to maintain the structural and chemical integrity of the original tissue.…”