title: Extravasated Platelet Aggregation in Liver Zone 3 Is Associated With Thrombocytopenia and Deterioration of Graft Function After Living-Donor Liver Transplant.
abstract: OBJECTIVE
  Continuous thrombocytopenia after liver transplant is associated with a less favorable prognosis, but this pathogenesis remains unclear. We focused on the consumption of platelets in the allograft. We assessed platelet consumption in allografts, and evaluated the pathology of platelet aggregation in an allograft tissue and its involvement in clinical outcomes.
  
  
  METHODS
  We took biopsy specimens from 20 patients. To examine the localization of platelet aggregation, CD42b was assayed immunohistochemically, and its level of expression correlated with clinical data and outcomes.
  
  
  RESULTS
  Platelet aggregation in zone 3 was 70%, compared with 30% in zone 1 and 50% in zone 2. Platelets were found mainly as extravasated platelet aggregates in local microenvironments. Patients were stratified according to the extent of extravasated platelet aggregates in zone 3 into extravasated platelet aggregate-negative and -positive groups. Graft weight/recipient body weight ratio with the extravasated platelet aggregatepositive group was significantly lower than that of the extravasated platelet aggregate-negative group. Platelet count after surgery was lower, while total bilirubin and prothrombin time/international normalized ratio were higher in the extravasated platelet aggregate-positive than they were in the extravasated platelet aggregate-negative group.
  
  
  CONCLUSIONS
  Extravasated platelet aggregates in the zone 3 of allograft tissue cause the consumption of platelets and continuous thrombocytopenia after transplant, and may be the clinical marker for deterioration of graft function. Platelet activation and degranulation following the release by platelets of some negative regulators may be involved partially in liver damage.
authors.affiliation: Gastroenterologic Surgery, Division of Cancer Medicine, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Nakanuma
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Miyashita
authors.forename: Hironori
authors.initials: H
authors.lastname: Hayashi
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Tajima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takamura
authors.forename: Isamu
authors.initials: I
authors.lastname: Makino
authors.forename: Katsunobu
authors.initials: K
authors.lastname: Oyama
authors.forename: Hisatoshi
authors.initials: H
authors.lastname: Nakagawara
authors.forename: Sachio
authors.initials: S
authors.lastname: Fushida
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ohta
mesh_terms: D064591:Allografts; D001706:Biopsy; D006801:Humans; D008099:Liver / Q000473:pathology*; D016031:Liver Transplantation; D019520:Living Donors; D059035:Perioperative Period; D010974:Platelet Aggregation; D011183:Postoperative Complications; D013921:Thrombocytopenia / Q000473:pathology*; D016896:Treatment Outcome