Approximately 500,000 bone-grafting procedures are performed each year in the United States.5 Autologous iliac crest bone graft continues to be the gold standard, because it provides essential elements for bone formation: progenitor cells, an osteoconductive matrix, and osteoinductive molecules. However, iliac crest harvest is associated with a significant number of complications and often provides an inadequate volume of graft.6 To address these limitations, much work has been done to improve alternative grafts with better osteoconductive matrices and exogenous delivery of osteoinductive agents such as the bone morphogenetic proteins (BMPs).7 Currently there are only a few basic point-of-care devices to isolate progenitor cells, which are essential elements to foster bone healing. However, these devices are limiting because they are expensive and because they either enrich a non-specific cell population potentially diluting out desired cells or they enrich a specific cell population using antibodies and consequently have safety concerns. Therefore, a safe, inexpensive device that could enrich adult stem cells from a bone marrow aspirate (BMA) or other tissue stroma at point-of-care would be of significant clinical benefit. In this phase II proposal, we will continue to develop a cell isolation device to enrich the multipotent subpopulation of cells in human bone marrow known as mesenchymal stem cells (MSCs). (*2)Furthermore, we will demonstrate versatility of the isolation device by showing that we can capture adult stem cells from adipose tissue. The advantage of adipose tissue is the availability of greater numbers of bone healing cells. We have identified and synthesized an MSC-binding peptide that can isolate adult stem cells from bone marrow and adipose tissue, and these isolated cells are multipotent. The MSC-binding peptide will be covalently attached to a solid support matrix and will form the functional core of the cell isolation device. The cells isolated will be captured and released using the prototype device, and different concentrations of cells will be tested in bone healing of a rat calvarial defect. An isolated pool of MSCs has the potential to serve key clinical functions in a range of indications including osteoarthritis, Chron's disease and soft tissue repair such as tendon, ligament or wounds. This product will provide a safe and cost-effective point-of-care isolation system for the preparation of autologous cells.
Bone grafting is widely used in orthopedic surgery to treat fractures and large bone defects and to achieve spinal fusions. However, harvesting a bone graft from patients is associated with a significant number of complications and often provides an inadequate amount of tissue. While alternatives to bone grafts have shown promise, there is still room for considerable improvement. Therefore, a device, like the one proposed in this SBIR application, that could isolate adult stem cells efficiently and quickly in the operating room would be of significant clinical benefit in a number of clinical indications.