title: Effect of activators and the phosphodiesterase inhibitors pentoxifylline and enoximone on the deformability of neutrophils in neonates and adults.
abstract: BACKGROUND
  Stimulated polymorphonuclear leukocytes (PMN) are extremely rigid compared to resting PMN. They may obstruct narrow vessels and contribute to ischaemic organ injury. Deformability is a prerequisite for both active and passive movement in the microcirculation.
  
  
  OBJECTIVE
  The investigation was designed to study whether stimulators and inhibitors of stimulation show different effects on deformability of neonatal and adult PMN.
  
  
  METHODS
  Deformability of PMN was assessed by complete aspiration of a PMN into a micropipette with an internal diameter of 5 microm. Blood samples from 20 neonates and 20 adults were studied before and after stimulation with N-formyl-methionyl-leucyl-phenylalanine (fMLP), interleukin-8 (IL-8) or tumour necrosis factor-alpha (TNF-alpha). Moreover, effects of the phosphodiesterase inhibitors Pentoxifylline (PTX) and Enoximone on the deformability of stimulated PMN were investigated.
  
  
  RESULTS
  fMLP, IL-8 and TNF-alpha significantly delayed aspiration times of PMN in relation to the concentrations of the stimulators. The addition of PTX or Enoximone to stimulated PMN increased the deformability up to 60% depending on the concentration of the inhibitors. No significant differences in the aspiration times were found between neonatal and adult PMN at any of the experimental conditions after activation with the three stimulators and treatment with the two inhibitors.
  
  
  CONCLUSIONS
  Neonatal and adult PMN show similar reduction of passive deformability when stimulated with either fMLP, IL-8 or TNF-alpha compared to resting PMN and a similar improvement of deformability in response to PTX or Enoximone.
authors.affiliation: Division of Neonatology, Department of Paediatrics, University of Heidelberg, Medical School, Heidelberg, Germany. peter_ruef@med.uni-heidelberg.de
authors.forename: P
authors.initials: P
authors.lastname: Ruef
authors.forename: J M B
authors.initials: JM
authors.lastname: Poeschl
authors.forename: C
authors.initials: C
authors.lastname: Simon
authors.forename: F
authors.initials: F
authors.lastname: Altfelder
authors.forename: E
authors.initials: E
authors.lastname: Craciun
authors.forename: O
authors.initials: O
authors.lastname: Linderkamp
mesh_terms: D000328:Adult; D017335:Enoximone / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007231:Infant, Newborn; D016209:Interleukin-8 / Q000494:pharmacology*; D008297:Male; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects*; D010431:Pentoxifylline / Q000494:pharmacology*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D004791:Enzyme Inhibitors; D016209:Interleukin-8; D010726:Phosphodiesterase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D009240:N-Formylmethionine Leucyl-Phenylalanine; D017335:Enoximone; D010431:Pentoxifylline