Glucose uptake variation by monocyte chemoattractant protein-1 attracted macrophages during foreign body response to microdialysis probes in vitro and in vivo

by Mou, Xiaodun; Lennartz, Michelle R.; Loegering, Daniel J.; Stenken, Julie Ann

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To successfully bioengineer the tissue surrounding an implanted sensor, it is necessary to fully understand the complex cellular events surrounding the device. The first step in this process is to understand how macrophages attach to the sensor surface. Mouse monocyte chemoattractant protein-1 (MCP-1) was employed to recruit macrophages to the implant in vitro and in vivo, and 2-deoxyglucose served as an internal std. to trace glucose uptake variation. Microdialysis probes (10 mm) with a polyethersulfone (PES) membrane were immersed in RAW 264.7 murine macrophage cells (1 million/mL) in the in vitro study. Two sep. dialysis probes were infused at 1.0 µL/min with either MCP-1, 10 ng/mL in phosphate-buffered saline (PBS), or PBS alone. Samples were collected every 30 min for 3 h. Glucose and 2-doexyglucose were quantified using anion-exchange chromatog. combined with pulsed amperometric detection. The extn. efficiencies (EEs) for 2-deoxyglucose were 52 ± 4% (n=6) and 70 ± 5% (n=6) in the MCP-1 and PBS perfused macrophages, resp. For the in vivo study, two identical microdialysis probes were implanted into the peritoneal cavity of two sep. male Sprague-Dawley rats, sep. The probes were perfused with either PBS or MCP-1 (2 ng/mL) in PBS soln. into the implantation site at 1.0 µL/min for an hour before 3-day implantation. The PES membrane surface from the MCP-1 perfused probe was seriously fouled after implantation compared with the PES membrane from the PBS perfused probe. These results suggest that attracted macrophages near the device exhibit altered glucose mass transport characteristics to the dialysis probe. Immunochem. staining or flow cytometry will be employed to further identify the cell types in the biofouling layer and how MCP-1 interacts with macrophages. We acknowledge NIH EB001441 for funding. on SciFinder(R)]