title: Splenectomy increases the number of circulating hematopoietic stem/progenitor cells in patients with hepatitis C virus-associated liver cirrhosis.
abstract: OBJECTIVE
  The spleen is not believed to contribute to hematopoiesis in healthy adults. However, several reports have demonstrated that the spleen in adults contains a large number of hematopoietic stem/progenitor cells (HSC). Although splenectomy increases platelet and leukocyte counts, the effects of splenectomy on circulating HSC have not been elucidated. In this study, we evaluated the association between the number of circulating HSC and splenectomy in patients with hepatitis C virus (HCV)-associated liver cirrhosis (LC).
  
  
  METHODS
  In 48 patients with various stages of HCV-associated chronic liver disease and seven patients with LC who underwent splenectomy, and 10 healthy volunteers, we determined the numbers of circulating CD34+cells and colony-forming unit culture by flow cytometry and methylcellulose culture, respectively. Plasma stromal cell-derived factor-1α (SDF-1α) concentrations were measured using an enzyme-linked immunosorbent assay.
  
  
  RESULTS
  The numbers of circulating CD34+cells and colony-forming unit culture decreased but the plasma SDF-1α concentration increased with the progression of liver disease. There was an inverse correlation between the number of circulating HSC and the plasma SDF-1α concentration. The numbers of circulating HSC and platelets were determined before and after splenectomy in seven patients with LC. In these patients, the numbers of circulating HSC and platelets increased significantly after splenectomy and the enhancing effect persisted for a long time.
  
  
  CONCLUSIONS
  Our data suggest that the spleen plays an important role in modulating HSC dynamics in patients with HCV-associated chronic liver disease. Our results also imply that splenectomy may improve liver function in patients with LC.
authors.affiliation: Department of Hematology and Oncology, Mie University Graduate School of Medicine, Tsu, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Masuya
authors.forename: Katsuya
authors.initials: K
authors.lastname: Shiraki
authors.forename: Kazushi
authors.initials: K
authors.lastname: Sugimoto
authors.forename: Norihiko
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Misao
authors.initials: M
authors.lastname: Yoneda
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kanayama
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Kazuko
authors.initials: K
authors.lastname: Ino
authors.forename: Isao
authors.initials: I
authors.lastname: Tawara
authors.forename: Kohshi
authors.initials: K
authors.lastname: Ohishi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sakurai
authors.forename: Masanobu
authors.initials: M
authors.lastname: Usui
authors.forename: Taizo
authors.initials: T
authors.lastname: Shiraishi
authors.forename: Shuji
authors.initials: S
authors.lastname: Isaji
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Takei
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Katayama
keywords: hematopoietic stem/progenitor cells; hepatitis C virus; liver cirrhosis; splenectomy