A rat model of chronic allograft liver rejection

CXCL4 Contributes to the Pathogenesis of Chronic Liver Allograft Dysfunction

Chronic liver allograft dysfunction (CLAD) remains the most common cause of patient morbidity and allograft loss in liver transplant patients. However, the pathogenesis of CLAD has not been completely elucidated. By establishing rat CLAD models, in this study, we identified the informative CLAD-associated genes using isobaric tags for relative and absolute quantification (iTRAQ) proteomics analysis and validated these results in recipient rat liver allografts. CXCL4, CXCR3, EGFR, JAK2, STAT3, and Collagen IV were associated with CLAD pathogenesis. We validated that CXCL4 is upstream of these informative genes in the isolated hepatic stellate cells (HSC). Blocking CXCL4 protects against CLAD by reducing liver fibrosis. Therefore, our results indicated that therapeutic approaches that neutralize CXCL4, a newly identified target of fibrosis, may represent a novel strategy for preventing and treating CLAD after liver transplantation.

Cyclosporine A disposition, hepatic and renal tolerance in Wistar rat

Cyclosporine A, a potent calcineurin inhibitor, has been widely used in organ transplantation and in the treatment of autoimmune diseases. It has, however, been shown to induce serious renal and hepatic side effects. The drug is also used in preclinical studies, but with little published information on the optimal dose and route of administration in rodents. Objectives of this study were to identify efficient and safe doses of cyclosporine A in rodent and to assess its effects on hepatic and renal functions. For this purpose, we tested the effects of different doses and administration routes of cyclosporine A (5, 2.5 and 1 mg/kg) administered during 28 days intraperitoneally, or by gastric feeding on Wistar rats. Our data indicate that rats injected intraperitoneally with 5 mg/kg/2d (every two days) exhibited trough cyclosporine A levels within known therapeutic range in human, but were subject to blood cyclosporine A accumulation, whereas the 5 mg/kg/d gavage resulted in only a small cyclosporine A accumulation over time. In both cases this accumulation was not deleterious to renal and hepatic functions, as shown by transaminase, urea, creatinine and bilirubin measurements.

Cytomegalovirus infection accelerates the process of chronic rejection in rat liver transplantation

OBJECTIVE

Analysis of the pathogenesis of cytomegalovirus (CMV) infection for rat chronic liver rejection.

METHODS

Based on animal models that we previously developed, we divided control and a CMV infection group to analyze survival, histopathology and rejection activity. The level and mRNA expression of transforming growth factor-β1, platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF) were measured in peripheral blood serum and liver tissue.

RESULTS

Obliterative arteriopathy and fibrosis was significantly greater in the CMV infection versus the control group (P < .05). PDGF mRNA expression in rat liver and in peripheral blood were significantly higher in the CMV infection versus the control group (P < .05). bFGF mRNA expression in the CMV infection group was also significantly higher than among the controls (P < .05).

CONCLUSIONS

CMV infection aggravated foam cell obliterative arteriopathy and liver fibrosis in chronic liver rejection, processes that accelerate the immune response, which may correlate with early high PDGF and bFGF expression.

High incidence of biliary complications in rat liver transplantation: Can we avoid it?

AIM: To investigate how to reduce the incidence of biliary complications in rat orthotopic liver transplantation.

METHODS: A total of 165 male Wistar rats were randomly divided into three groups: Group A, orthotropic liver transplantation with modified “two-cuff” technique; Group B, bile duct was cut and reconstructed without transplantation; and Group C, only laparotomy was performed. Based on the approaches used for biliary reconstruction, Group A was divided into two sub-groups:A1 (n = 30), duct-duct reconstruction, and A2 (n = 30), duct-duodenum reconstruction. To study the influence of artery reconstruction on bile duct complication, Group B was divided into four sub-groups: B1 (n = 10), duct-duct reconstruction with hepatic artery ligation, B2 (n = 10), duct-duct reconstruction without hepatic artery ligation, B3 (n = 10), duct-duodenum reconstruction with hepatic artery ligation, and B4 (n = 10), duct-duodenum reconstruction without hepatic artery ligation. The samples were harvested 14 d after operation or at the time when significant biliary complication was found.

RESULTS: In Group A, the anhepatic phase was 13.7 ± 1.06 min, and cold ischemia time was 50.5 ± 8.6 min. There was no significant difference between A1 and A2 in the operation duration. The time for biliary reconstruction was almost the same among all groups. The success rate for transplantation was 98.3% (59/60). Significant differences were found in the incidence of biliary complications in Groups A (41.7%), B (27.5%) and C (0%). A2 was more likely to have biliary complications than A1 (50% vs 33.3%). B3 had the highest incidence of biliary complications in Group B.

CONCLUSION: Biliary complications are almost inevitable using the classical “two cuff” techniques, and duct-duodenum reconstruction is not an ideal option in rat orthotopic liver transplantation.

Animal models of chronic allograft injury: contributions and limitations to understanding the mechanism of long-term graft dysfunction

Advances in immunosuppression have reduced the incidence of acute graft loss after transplantation, but long-term allograft survival is still hindered by the development of chronic allograft injury, a multifactorial process that involves both immunologic and nonimmunologic components. Because these components become defined in the clinical setting, development of animal models enables exploration into underlying mechanisms leading to long-term graft dysfunction. This review presents animal models that have enabled investigation into chronic allograft injury and discusses pivotal models currently being used. The mechanisms uncovered by these models will ultimately lead to development of new therapeutic options to prevent long-term graft dysfunction.

Establishment of an acute graft-versus-host disease model following liver transplantation in donor-dominant one-way major histocompatibility complex matching rats

Acute graft-versus-host disease is an uncommon but devastating complication following liver transplantation (LTx-aGVHD). We investigated whether a rat model of LTx-aGVHD could be established using Lewis rat donors and (LewisXBN)F1 rats as recipients, which provides favorable conditions for studies of graft-versus-host reaction or disease. Replacement of (LewisXBN)F1 livers by Lewis livers alone was not sufficient to induce aGVHD; all recipients grew in a normal pattern as the syngeneic liver transplantation (LT) from Lewis to Lewis rat. However, when various numbers of donor splenocytes (1 x 10(8), 2 x 10(8), 3 x 10(8), 4 x 10(8)) were transferred simultaneously with the LT, the morbidities of lethal aGVHD were 16.7%, 50%, 83.3%, and 100%, respectively. The clinical courses as well as histologic analyses of skin and colon showed typical aGVHD characteristics. However, unlike transfusion-associated aGVHD, the liver graft was not involved. These clinical and histologic characteristics of aGVHD were consistent with those in humans who develop aGVHD after LT. Thus, a reproducible rat model of LTx-aGVHD was developed by performing LT from Lewis to (LewisXBN)F1 rats in combination with donor splenocyte transfusion. This model may be useful for further studies on the mechanisms and effective treatment modalities for LTx-aGVHD.