Monocytes and macrophages in tissue repair: Implications for immunoregenerative biomaterial design.

Monocytes and macrophages play a critical role in tissue development, homeostasis, and injury repair. These innate immune cells participate in guiding vascular remodeling, stimulation of local stem and progenitor cells, and structural repair of tissues such as muscle and bone. Therefore, there is a great interest in harnessing this powerful endogenous cell source for therapeutic regeneration through immunoregenerative biomaterial engineering.

Bioactive lipid coating of bone allografts directs engraftment and fate determination of bone marrow-derived cells in rat GFP chimeras.

Bone grafting procedures are performed to treat wounds incurred during wartime trauma, accidents, and tumor resections. Endogenous mechanisms of repair are often insufficient to ensure integration between host and donor bone and subsequent restoration of function. We investigated the role that bone marrow-derived cells play in bone regeneration and sought to increase their contributions by functionalizing bone allografts with bioactive lipid coatings.

The promotion of mandibular defect healing by the targeting of S1P receptors and the recruitment of alternatively activated macrophages.

Endogenous signals originating at the site of injury are involved in the paracrine recruitment, proliferation, and differentiation of circulating progenitor and diverse inflammatory cell types. Here, we investigate a strategy to exploit endogenous cell recruitment mechanisms to regenerate injured bone by local targeting and activation of sphingosine-1-phosphate (S1P) receptors. A mandibular defect model was selected for evaluating regeneration of bone following trauma or congenital disease.

Regulation of angiogenesis and bone regeneration with natural and synthetic small molecules.

Regeneration of bone requires the coordinated processes of angiogenesis and osteogenesis. These repair mechanisms are closely linked through both direct cell-cell contact and indirect paracrine signaling among osteoblasts, endothelial cells, and other cell types. The vasculature provides a source of nutrients, oxygen, metabolic substrates, and access for circulating cells that help to support new bone formation.

Long-term culture of HL-1 cardiomyocytes in modular poly(ethylene glycol) microsphere-based scaffolds crosslinked in the phase-separated state.

Poly(ethylene glycol) (PEG) microspheres were assembled around HL-1 cardiomyocytes to produce highly porous modular scaffolds. In this study we took advantage of the immiscibility of PEG and dextran to improve upon our previously described modular scaffold fabrication methods. Phase separating the PEG microspheres in dextran solutions caused them to rapidly deswell and crosslink together, eliminating the need for serum protein-based crosslinking.