title: Peritoneal macrophages are distinct from monocytes and adherent macrophages.
abstract: OBJECTIVE
  Peritoneal macrophages are used in many studies related to atherosclerosis. In situ, they are non-adherent and upon culturing, they adhere and function as scavengers of modified lipoproteins and dead apoptotic cells. They also produce growth factors, suggesting that they may provide life-supporting function as well. In this study, we propose that macrophage adherence plays a major role in their function and propose a novel concept that non-adherent macrophages are poor scavengers and may delay the process of apoptosis by secretion of growth factors.
  
  
  RESULTS
  We analyzed non-adherent and adherent macrophages for changes in receptor expression, growth factor production and function by microarrays, real-time PCR, and western blot analyses. Our results indicate that adherent macrophages have increased expression of scavenger receptors as compared to fresh peritoneal cells. While genes for many growth factors were expressed in both non-adherent and adherent macrophages, the milk fat globule-epidermal growth factor 8 protein (MFG-E8) that recognizes and takes up apoptotic cells was specifically enhanced in non-adherent cells. Furthermore, early apoptotic endothelial cells demonstrated signs of delayed apoptosis when incubated in the presence of peritoneal lavage fluid that was shown to contain MFG-E8. Functional arrays indicated that peritoneal non-adherent macrophages represent a class of macrophages, distinct from either blood monocytes or adherent cultured macrophages.
  
  
  CONCLUSIONS
  These results suggest that the adherence status of macrophages may play a major role in their functions.
authors: Division of Cardiothoracic Surgery, The Ohio State University Medical Center, Columbus, OH 43210, USA.
authors: Krithika
authors: K
authors: Selvarajan
authors: Leni
authors: L
authors: Moldovan
authors: Aluganti Narasimhulu
authors: AN
authors: Chandrakala
authors: Dmitry
authors: D
authors: Litvinov
authors: Sampath
authors: S
authors: Parthasarathy
mesh_terms: D000818:Animals; D017209:Apoptosis; D001202:Ascitic Fluid / Q000378:metabolism; D015153:Blotting, Western; D002448:Cell Adhesion; D002478:Cells, Cultured; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000145:classification* / Q000378:metabolism / Q000473:pathology; D017737:Macrophages, Peritoneal / Q000145:classification* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D009000:Monocytes / Q000145:classification* / Q000378:metabolism / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D010533:Peritoneal Lavage; D060888:Real-Time Polymerase Chain Reaction; D051116:Receptors, Scavenger / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D051116:Receptors, Scavenger