title: Prolongation of cardiac allograft survival by syngeneic hematopoietic stem/progenitor cell transplantation in mice.
abstract: BACKGROUND
  Organ transplantation is a rapidly developing field, being the only effective treatment for end-stage organ disease. However, the associated immunosuppressant therapy has numerous direct and indirect adverse effects. Hematopoietic stem cell transplantation (HSCT), via immune reconstitution, offers an alternative method of treatment. In this study, we determined the cardiac allograft survival in mice treated with syngeneic HSCT or hematopoietic progenitor cell transplantation (HPCT).
  
  
  METHODS
  BALB/c and C57BL/6 mice were randomly divided into three groups. Mice in Group A (n=7) were untreated while those in Group B (n=8) and C (n=7) were treated with HPCT and HSCT, respectively. Cervical heterotopic cardiac transplantation models were established in all groups and cardiac grafts were observed throughout. Regulatory T (Treg) cell expression in peripheral blood was analyzed by flow cytometry. We recorded the cardiac allograft survival time and constructed Kaplan-Meier survival curves.
  
  
  RESULTS
  The number of Treg cells in Group B was significantly higher than that in Group C (P<0.05). The survival time of mice from each group differed significantly according to Kaplan-Meier/log-rank analysis (P<0.01). A total of 62.5% of the grafts in Group B showed long-term survival (>100 days); all the mice in Group A died within 9 days, compared with 59 days in Group C.
  
  
  CONCLUSIONS
  We conclude that syngeneic HSCT and HPCT can prolong cardiac allograft survival in mice. These two methods could be promising ways to induce immune tolerance in future organ transplantation.
authors.affiliation: Department of Hepato-biliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Li
authors.forename: Xin
authors.initials: X
authors.lastname: Meng
authors.forename: Kaishan
authors.initials: K
authors.lastname: Tao
authors.forename: Kefeng
authors.initials: K
authors.lastname: Dou