title: Quantification and functional analysis of chemotaxis by laser scanning cytometry.
abstract: BACKGROUND
  Evaluation of chemotaxis assays traditionally relies on cumbersome and at times inaccurate visual counting. Moreover, many physiologic parameters that could be evaluated in conjunction with chemotactic migration, aside from morphologic changes, usually are not assessed due to the lack of a simultaneous method of analysis. We tested the suitability of laser scanning cytometry (LSC) as a convenient platform for counting migrated cells and for concurrent analysis of some features associated with their physiologic status.
  
  
  METHODS
  We induced migration of THP-1 monocytes across Nuclepore filters with monocyte chemotactic protein-1 or vascular endothelial growth factor, alone or in combination. Filters were collected, and cells were fixed on filters and stained with the nuclear stain propidium iodide. Chemotactic indices were obtained by counting representative microscopic fields and by scanning the filters in LSC mode.
  
  
  RESULTS
  We found an excellent correlation between direct counting and LSC. In addition, the software tools embodied in the LSC instrument allowed the observation of changes in nuclear compactness (increase in propidium iodide brightness) and morphology (increase in nuclear area and perimeter) that occurred in transmigrated cells. Monocyte chemotactic protein-1 and vascular endothelial growth factor acted as additive stimuli on these parameters.
  
  
  CONCLUSIONS
  LSC analysis of cells undergoing chemotaxis provides a reliable and comprehensive assessment of the numbers and distribution of migrated cells and some of their nuclear parameters. The method can be easily extended to include the assessment of coincident molecular changes in cells due to chemotactic stimulation.
authors.affiliation: Department of Internal Medicine, Division of Cardiology and Biomedical Engineering Center, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Omar I
authors.initials: OI
authors.lastname: Butt
authors.forename: Padmavathy
authors.initials: P
authors.lastname: Krishnan
authors.forename: Sumant S
authors.initials: SS
authors.lastname: Kulkarni
authors.forename: Leni
authors.initials: L
authors.lastname: Moldovan
authors.forename: Nicanor I
authors.initials: NI
authors.lastname: Moldovan
mesh_terms: D002460:Cell Line; D002634:Chemotaxis, Leukocyte; D006801:Humans; D047569:Laser Scanning Cytometry; D009000:Monocytes / Q000166:cytology / Q000502:physiology*