title: Hofbauer cell activation and its increased glucose-6-phosphate dehydrogenase activity in second trimester-spontaneous abortion: an ultrastructural dual staining enzyme-cytochemical study.
abstract: OBJECTIVE
  While activated/phagocytosing phagocytes infiltrating to the chorioamnion are considered to be one of the causal agents of preterm labor onset, whether placental villous macrophages (Hofbauer cells) are activated/phagocytosing in this condition is not known.
  
  
  METHODS
  We concomitantly localized two important phagocytosis-related enzymes, acid phosphatase (ACP) and glucose-6-phosphate dehydrogenase (G6PD), in Hofbauer cells in second trimester placental villi, and compared them with those from infection-related second trimester-spontaneous abortion (miscarriage) placentas.
  
  
  RESULTS
  There were two types of Hofbauer cells. The first cells exhibited ACP stainings confined to the lysosomes, suggesting that they are dormant/non-activated cells. Approximately two-thirds of these cells showed weak G6PD labeling on the cytosolic side of endoplasmic reticula, and G6PD labeling was hardly recognizable in the remaining one-third. The second cells, possessing large phagosomes, showed marked ACP labeling in the phagosomes, suggesting that they are activated/phagocytosing cells. All these cells exhibited G6PD labeling, and in 'bursting cells' (possibly hyperactivated cells) G6PD deposits were marked. The percentage of activated cells in miscarriage placentas was significantly higher (44.8 +/- 6.0%) than that in gestational age-matched controls (17.4 +/- 5.3%).
  
  
  CONCLUSIONS
  These observations indicated that (1) G6PD activity increased in activated/phagocytosing Hofbauer cells, and (2) the percentage of phagocytosing cells increased in infection-related miscarriage placentas. Hofbauer activation and G6PD may play an role in the pathogenesis/pathophysiology of preterm labor onset.
authors.affiliation: Department of Obstetrics and Gynaecology, Jichi Medical School, Minamikawachi-machi, Kawachi-gun, Tochigi-ken, Japan. matsushi@jichi.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Matsubara
authors.forename: T
authors.initials: T
authors.lastname: Takayama
authors.forename: T
authors.initials: T
authors.lastname: Yamada
authors.forename: R
authors.initials: R
authors.lastname: Usui
authors.forename: A
authors.initials: A
authors.lastname: Izumi
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
authors.forename: A
authors.initials: A
authors.lastname: Ohkuchi
authors.forename: H
authors.initials: H
authors.lastname: Shibahara
authors.forename: I
authors.initials: I
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D000022:Abortion, Spontaneous / Q000201:enzymology* / Q000209:etiology; D000135:Acid Phosphatase / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000201:enzymology / Q000648:ultrastructure; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism*; D006801:Humans; D007239:Infections / Q000150:complications; D008262:Macrophage Activation / Q000502:physiology*; D008264:Macrophages / Q000166:cytology* / Q000201:enzymology / Q000648:ultrastructure; D008854:Microscopy, Electron; D010588:Phagosomes / Q000201:enzymology / Q000648:ultrastructure; D010920:Placenta / Q000166:cytology* / Q000201:enzymology / Q000648:ultrastructure; D011247:Pregnancy; D011262:Pregnancy Trimester, Second
chemical_list: D005954:Glucosephosphate Dehydrogenase; D000135:Acid Phosphatase