The finding will go a long way in addressing many of thechallenges associated with targeting stem cells to specific tissues—what Karpcalls "the big unmet need of stem cell research." While conventional celltherapies that include local administration of cells can be useful, they aretypically more invasive, with limited potential for multiple doses. For example,"when treating heart attacks or heart failure, injecting the cells directlyinto the heart can be an invasive procedure, and typically this approach canonly be performed once," Karp says.
Systemic infusion is desired, says Karp, as it minimizes theinvasiveness of cell therapy and maximizes practical aspects of repeated doses.
"We're getting to a point in time where one can obtainalmost unlimited quantities of almost any cell type in the lab—but what I thinkis really the biggest limitation to moving cell therapies to the clinic isbeing able to deliver cells to targeted tissues in the body, while maintaininghigh survival and efficacy rates. We posed the question: Can we target cells tospecific tissues using a non-viral approach that is chemical in nature? To dothis, we covalently modified the cell surface using a very simple approach atambient conditions. We chemically attached to the cell surface a ligand thatcan interact with something expressed in inflammation."
The researchers concluded that, as the understanding of themechanisms of cell trafficking grows, the ability to improve homing to specifictissues through engineered approaches should significantly enhance cell therapyby reducing the invasiveness of local administration, permitting repeat dosing andpotentially reducing the number of cells required to achieve a therapeuticeffect, ultimately providing better outcomes for patients.
According to Karp, this approach can be used to systemicallytarget bone-producing cells to the bone marrow to treat osteoporosis,cardiomyocytes to the heart to treat ischemic tissue, neural stem cells to thebrain to treat Parkinson's disease or endothelial progenitor cells to sites ofperipheral vascular disease to promote formation of new blood vessels.
The approach will translate to the core technology of a newstem cell company, he adds.
"Most of the companies in this area have been focusedon obtaining the right cell type and then delivering that cell, but the problemis that there hasn't been much innovation in the delivery area of this sciencethat is critical," Karp says. "We are in the process of translating thistechnology and other cell modification approaches within a new startupcompany."
