title: Tumor necrosis factor-alpha in the placenta is not elevated in pre-eclamptic patients despite its elevation in peripheral blood.
abstract: OBJECTIVE
  Tumor necrosis factor-alpha (TNF-alpha) is present in human placental and uterine cells at the early and late stages of gestation and promotes the regulation of trophoblast growth and invasion. We evaluated whether TNF-alpha levels in the placenta and blood of pre-eclamptic women differed from those with normal pregnancies.
  
  
  METHODS
  The subjects were 39 pregnant women carrying single fetuses (21 normal-pregnant and 18 pre-eclamptic patients). Their average gestational age at entry was 38-39 weeks. Peripheral blood was collected before the onset of labor and separated serum was stored at -20 degrees C. A tissue segment of the placenta was cut and frozen in liquid nitrogen immediately after delivery at -80 degrees C. The frozen placental tissue was added to phosphate-buffered saline. The tissue was fully homogenized and centrifuged. Separated supernatant was stored at -80 degrees C. TNF-alpha levels in separated serum and TNF-alpha and total protein (TP) levels in separated supernatant were measured. The presence of TNF-alpha in the placenta was evaluated by immunohistochemistry in five pre-eclamptic and five normal-pregnant patients.
  
  
  RESULTS
  Serum TNF-alpha levels were higher in pre-eclampsia than in normal pregnancies. However, TNF-alpha/TP levels in the placenta did not differ significantly between the two groups. As for TNF-alpha immunostaining of trophoblastic cells in the placenta, it was weak in three and moderate in two of the normal pregnancies, while it was absent in two, weak in one, and moderate in two in the pre-eclampsia group.
  
  
  CONCLUSIONS
  We demonstrated no significant increase in TNF-alpha/TP levels in the placenta in pre-eclampsia despite a significant increase in serum TNF-alpha levels. There was no strong immunostaining for TNF-alpha detected by immunohistochemistry in the pre-eclampsia group. These findings suggest that TNF-alpha in the placenta is not a key cytokine to interfere with normal trophoblast invasion into the myometrium in pre-eclampsia, and that sources other than the placenta may contribute to the elevated levels of TNF-alpha found in the circulation of pre-eclamptic patients.
authors.affiliation: Department of Obstetrics and Gynecology, Koshigaya Hospital, Dokkyo University School of Medicine, Koshigaya-shi, Saitama, Japan. mhayashi@lilac.plala.or.jp
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hayashi
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Ueda
authors.forename: Takehiko
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Sohma
authors.forename: Mitsuei
authors.initials: M
authors.lastname: Shibazaki
authors.forename: Takeyoshi
authors.initials: T
authors.lastname: Ohkura
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Inaba
mesh_terms: D000328:Adult; D001724:Birth Weight; D001794:Blood Pressure; D001798:Blood Proteins / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D010920:Placenta / Q000378:metabolism*; D011225:Pre-Eclampsia / Q000378:metabolism*; D011247:Pregnancy; D012044:Regression Analysis; D044967:Serum / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D001798:Blood Proteins; D014409:Tumor Necrosis Factor-alpha