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Regulation of proliferation of peritoneal tissue repair cells by peritoneal macrophages
M Fukasawa1, J D Campeau, D L Yanagihara
1Department of Obstetrics and Gynecology, University of Southern California School of Medicine, Los Angeles 90033.
Abstract:
Macrophages produce soluble mediators which modulate fibroblast growth during tissue repair. Interaction between tissue repair fibroblasts (TRC) and regulatory proteins from surgically elicited macrophages is important for peritoneal reepithelialization. In this study, we compared the effects of an extract from postsurgical macrophage spent medium with those of known growth factors on TRC collected from injured peritoneum to evaluate certain characteristics of macrophage secretory products on peritoneal healing. Rabbits underwent a midline laparotomy followed by resection and reanastomosis of the ileum or abrasion of the abdominal wall. TRC were then collected at various times after surgery. Peritoneal macrophages recovered from nonsurgical or postsurgical rabbits were cultured for 2 days in vitro. The peak of thymidine incorporation by TRC occurred on day 5 after surgery; this gradually decreased with extended postsurgical times. Fibroblast growth factor and epidermal growth factor stimulated, whereas TGF-beta inhibited, [3H]thymidine incorporation into TRC. Maximal thymidine incorporation occurred when TRC from Postsurgical Day 5 were cultured with an extract from postsurgical macrophage spent medium. However, when TRC recovered from Postsurgical Days 2 and 10 were cultured with an extract of postsurgical macrophage spent medium, they showed greater stimulation than Day 5 TRC. These data suggest that postsurgical macrophages may produce an array of factors that stimulate fibroblast growth and differentiation and may in turn affect tissue repair throughout the wound healing process.
Insights
Postsurgical macrophages release factors that influence fibroblast growth, crucial for tissue repair. This study highlights their role in peritoneal healing by examining macrophage-derived mediators on fibroblast activity.
Area of Science:
- Cell Biology
- Immunology
- Wound Healing Research
Background:
- Macrophages are key immune cells involved in tissue repair.
- Their secreted mediators can influence fibroblast behavior.
- Understanding these interactions is vital for improving wound healing outcomes.
Purpose of the Study:
- To investigate the impact of macrophage-derived factors on fibroblast growth.
- To compare the effects of postsurgical macrophage spent medium with known growth factors.
- To evaluate the role of macrophage secretory products in peritoneal healing.
Main Methods:
- Rabbits underwent surgical procedures (laparotomy, ileum resection/reanastomosis, or abdominal wall abrasion).
- Tissue repair fibroblasts (TRC) were collected at various post-surgical times.
- Peritoneal macrophages were cultured, and their spent medium extract was applied to TRC to assess thymidine incorporation.
Main Results:
- Fibroblast growth factor and epidermal growth factor stimulated TRC proliferation, while TGF-beta inhibited it.
- Macrophage spent medium extract showed maximal TRC stimulation on post-surgical Day 5.
- Greater fibroblast stimulation was observed with TRC from post-surgical Days 2 and 10 compared to Day 5.
Conclusions:
- Postsurgical macrophages produce diverse factors that stimulate fibroblast growth and differentiation.
- These macrophage-derived factors play a significant role in the wound healing process.
- Further research into these mediators could lead to therapeutic strategies for tissue repair.