title: Differential adhesion of polymorphous neutrophilic granulocytes to macro- and microvascular endothelial cells under flow conditions.
abstract: OBJECTIVE
  As one of the important active barriers in the human organism, endothelial cells (EC) play a central role in the biological reaction to a variety of stimuli, e.g. during the induction and regulation of inflammation, as well as in the reaction to transplantation and biomaterial implantation. In the study of endothelial function, the most widely used in vitro model is that of human umbilical vein EC (HUVEC), i.e. an EC type of embryonic and macrovascular origin. However, many of the important pathological processes occur at microvascular level, thus questioning the validity of the HUVEC model. Moreover, the morphological and functional heterogeneity of the endothelium in the various organs, e.g. kidney, liver and lung, must be taken into consideration. The purpose of the present study was to use a dynamic cell culture system to compare the reactions of HUVEC and human pulmonary microvascular EC (HPMEC) to pro-inflammatory stimulation.
  
  
  METHODS
  HUVEC and HPMEC in monolayer culture were stimulated by tumor necrosis factor-alpha (TNFalpha) in a parallel-plate flow chamber. Short- (4 h) and long-term (12 h) stimulation were compared. As a functional parameter, the adhesion of human peripheral blood polymorphonuclear granulocytes (PMN) to EC was quantitated both under venous and arterial flow conditions.
  
  
  RESULTS
  Short-term (4 h) TNFalpha stimulation and venous flow conditions elicited a 32% higher PMN adhesion to HPMEC compared with HUVEC, whereas under arterial flow conditions no statistically significant differences were found. Following longer-term (12 h) TNFalpha stimulation, PMN adhesion to HPMEC was 65% higher than to HUVEC under venous flow. Under arterial flow no differences were detected.
  
  
  CONCLUSIONS
  The present results provide new data on the heterogeneity of the endothelium and affect a central element in microvascular pathology, namely granulocyte-endothelial interactions. Moreover, this paper emphasizes the necessity to evaluate the in vitro models of the endothelium with respect to the extrapolation to the situation in vivo.
authors.affiliation: Institute of Pathology, Johannes Gutenberg University of Mainz, Mainz, Germany. otto@pathologie.klinik.uni-mainz.de
authors.forename: M
authors.initials: M
authors.lastname: Otto
authors.forename: F
authors.initials: F
authors.lastname: Bittinger
authors.forename: J
authors.initials: J
authors.lastname: Kriegsmann
authors.forename: C J
authors.initials: CJ
authors.lastname: Kirkpatrick
mesh_terms: D002448:Cell Adhesion / Q000502:physiology*; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology*; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D011652:Pulmonary Circulation / Q000502:physiology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology / Q000502:physiology
chemical_list: D014409:Tumor Necrosis Factor-alpha