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Updated: Sep 17, 2026
Functional Characterization of Regulatory Macrophages That Inhibit Graft-reactive Immunity
Published on: June 7, 2017
Early Macrophage Infiltration Improves Fat Graft Survival by Inducing Angiogenesis and Hematopoietic Stem Cell
Junrong Cai1,2, Jingwei Feng1,2, Kaiyang Liu1,2
1Guangzhou, Guangdong, People's Republic of China.
Background:
Fat grafting is a popular soft-tissue filler method; however, its results are variable and technique-dependent. Macrophages are present in fat grafts and closely associated with tissue regeneration. The authors hypothesized that activation/depletion of early macrophages in transferred fat improves/impairs fat graft survival.
Methods:
Mouse inguinal fat (approximately 150 mg) was transferred autologously. Fat grafting was first performed without other manipulations to obtain baseline information. Then, liposome-encapsulated clodronate and macrophage-colony stimulating factor were used in a mouse fat grafting model for local macrophage depletion or activation. The authors examined the graft stromal vascular fraction by fluorescence-activated cell sorting at 1, 2, 4, and 12 weeks after transplantation in manipulation and control groups. Graft weight, vascularization, and secreted factors were also compared.
Results:
Early depletion of macrophages resulted in incompetent angiogenesis, feeble Sca-1/CD45 stem cell recruitment, and eventually a poor retention rate (34 ± 6 mg versus control 84 ± 15 mg; p = 0.006), whereas up-regulated macrophages allowed better angiogenesis and survival (117 ± 12 mg versus control, 84 ± 15 mg; p = 0.043).
Conclusions:
In fat grafting, macrophages and their polarization initiated changes in the levels of dominant secreted factors and influenced blood-derived stem cell infiltration, indicating that macrophages were crucial for tissue revascularization. The macrophage manipulation models described here show that graft macrophage number can profoundly influence graft survival.
