title: Stimulation of oval cell and hepatocyte proliferation by exogenous bombesin and neurotensin in partially hepatectomized rats.
abstract: OBJECTIVE
  To investigate the effect of the neuropeptides bombesin (BBS) and neurotensin (NT) on oval cell proliferation in partially hepatectomized rats not pretreated with a known hepatocyte inhibitor.
  
  
  METHODS
  Seventy male Wistar rats were randomly divided into five groups: I = controls, II = sham operated, III = partial hepatectomy 70% (PHx), IV = PHx + BBS (30 μg/kg per day), V = PHx + NT (300 μg/kg per day). Forty eight hours after liver resection, portal endotoxin levels and hepatic glutathione redox state were determined. α-fetoprotein (AFP) mRNA (in situ hybridisation), cytokeratin-19 and Ki67 antigen expression (immunohistochemistry) and apoptosis (TUNEL) were evaluated on liver tissue samples. Cells with morphological features of oval cells that were cytokeratin-19 (+) and AFP mRNA (+) were scored in morphometric analysis and their proliferation was recorded. In addition, the proliferation and apoptotic rates of hepatocytes were determined.
  
  
  RESULTS
  In the control and sham operated groups, oval cells were significantly less compared to groups III, IV and V (P < 0.001). The neuropeptides BBS and NT significantly increased the proliferation of oval cells compared to group III (P < 0.001). In addition, BBS and NT induced a significant increase of hepatocyte proliferation (P < 0.001), whereas it decreased their apoptotic activity (P < 0.001) compared to group III. BBS and NT significantly decreased portal endotoxemia (P < 0.001) and increased the hepatic GSH: GSSG ratio (P < 0.05 and P < 0.001, respectively) compared to group III.
  
  
  CONCLUSIONS
  BBS and NT stimulated oval cell proliferation in a model of liver regeneration, without use of concomitant suppression of hepatocyte proliferation as oval cell activation stimuli, and improved the hepatocyte regenerative response. This peptides-induced combined stimulation of oval cell and hepatocyte proliferation might serve as a possible treatment modality for several liver diseases.
authors.affiliation: Department of Internal Medicine, University Hospital of Patras, Patras 26504, Greece. sassim@upatras.gr
authors.forename: Stelios F
authors.initials: SF
authors.lastname: Assimakopoulos
authors.forename: Athanassios C
authors.initials: AC
authors.lastname: Tsamandas
authors.forename: Ilias H
authors.initials: IH
authors.lastname: Alexandris
authors.forename: Christos
authors.initials: C
authors.lastname: Georgiou
authors.forename: Constantine E
authors.initials: CE
authors.lastname: Vagianos
authors.forename: Chrisoula D
authors.initials: CD
authors.lastname: Scopa