Journal of orthopaedic research : official publication of the Orthopaedic Research Society
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This study presents a novel biodegradable alginate delivery system for antibiotics and bone cells to treat infected bone defects. About 2 x 10(7) New Zealand rabbit mesenchymal stem cells (MSCs) and 5 mL vancomycin solution (50 mg/mL) were added to 5 mL of 2.5% (w/v) sodium alginate solution to form biodegradable antibiotic and MSCs alginate beads 3 mm in diameter. The alginate beads were then cultured in an osteogenic medium for 14 days. ⋯ The results of in vitro study demonstrated sustained elution of vancomycin from the alginate carrier for 14 days and good osteogenic differentiation of cultured MSCs in the alginate carrier matrix. The results of in vivo study demonstrated the implanted MSCs participating in new bone formation. Based on experimental evidence, development of a biodegradable alginate carrier system for antibiotics and bone cells is possible, providing a potential treatment procedure for infected bone defects.
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Vascular damage accompanying skeletal injury leads to an ischemic environment, and in clinical settings the extent of vascular damage is directly correlated with failure of skeletal repair. However, the exact mechanism(s) underlying ischemia-related defects in bone healing are not well understood. To better understand the mechanism and to facilitate development of novel interventions to treat ischemic fractures, a mouse model of long bone fracture healing in an ischemic environment was created. ⋯ In stabilized fractures, which healed through direct bone formation in the nonischemic controls, ischemia decreased the amount of bone formation at days 10 and 14 (n = 5/time point) but did not induce cartilage formation. These data reveal that an ischemic insult in the hind limb prior to fracture leads to a delayed union or a nonunion, but does not favor formation of cartilage over bone. This model will be useful for testing novel therapeutic regimens to stimulate fracture healing.