title: Expression of CD34 in pulmonary endothelial cells in vivo.
abstract: OBJECTIVE
  The morphological phenotype of endothelial cells (EC) is specific for individual types of vessels. There are, however, no studies on the phenotypical diversity of EC in human lung tissue. The influences exerted by physiological factors (e.g. age, sex) or pathological factors (e.g. pulmonary hypertension) on EC have not been ascertained up to now.
  
  
  METHODS
  In order to determine the influence of pulmonary hypertension (PH), age and sex on EC, we localized the expression of the endothelial marker CD34 immunohistologically by light microscopy and laser scanning microscopy in lung tissue specimens from children and adults.
  
  
  RESULTS
  Capillary EC showed a stronger staining reaction than EC in arteries, veins, arterioles or venules. The staining intensity increased with age in veins and arteries and decreased with age in venules, arterioles and capillaries. Sex exerted no statistically significant influence. CD34 was generally more strongly expressed in specimens with PH than in those without.
  
  
  CONCLUSIONS
  The study demonstrates for the first time that (1) CD34 is heterogeneously expressed by human pulmonary EC, and (2) the physiological/pathophysiological factors age/PH influence CD34 expression. Hence a correlation between CD34 expression and its role as adhesion molecule and a link between CD34 expression and maturation are subject of discussion.
authors.affiliation: Institute of Pathology, University Clinic Bergmannsheil, Bochum, Germany. annette.mueller@ruhr-uni-bochum.de
authors.forename: Annette M
authors.initials: AM
authors.lastname: Müller
authors.forename: Maya
authors.initials: M
authors.lastname: Nesslinger
authors.forename: Guido
authors.initials: G
authors.lastname: Skipka
authors.forename: Klaus-Michael
authors.initials: KM
authors.lastname: Müller
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D018952:Antigens, CD34 / Q000378:metabolism*; D002196:Capillaries / Q000378:metabolism / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D004730:Endothelium, Vascular / Q000378:metabolism*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000378:metabolism / Q000473:pathology; D007124:Immunoenzyme Techniques; D007223:Infant; D008168:Lung / Q000098:blood supply*; D018613:Microscopy, Confocal; D008875:Middle Aged
chemical_list: D018952:Antigens, CD34