Approximately 500,000 bone-grafting procedures are performed each year in the United States. 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. To overcome these limitations, multipotent Mesenchymal Stem Cells (MSCs) have been added to bone graft substitutes and explored for use in tissue engineering applications, such as spinal fusions and bone defect repairs. Bone marrow derived mesenchymal stem cells (BMSCs) are well characterized in their ability to differentiate into cells and tissues of mesodermal origin;however, their frequency in the mononuclear fraction of processed bone marrow is very low. Adipose derived stem cells (ASCs) have been proposed as an alternative to BMSCs for cell therapy because the frequency of multipotent ASCs found in the stromal vascular fraction (SVF) of processed lipoaspirate can be several hundred-fold greater than the mononuclear fraction of bone marrow aspirate (BMA), depending on the donor. Currently there are only a few basic point-of-care devices to concentrate 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. In this phase 2 proposal, we will develop a point-of-care autologous ASC enrichment system for bone grafting that eliminates the need for ex vivo cell expansion prior to implantation.
Bone grafting is widely used in orthopaedic 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 that could directly isolate progenitor cells from complex biological fluids, and then be used at point-of-care in the operating room, would be of significant clinical benefit.
