Tadahiro Uemura

Liver retransplantation for primary nonfunction: Analysis of a 20-year single-center experience†

Initial graft function following liver transplantation is a major determinant of postoperative survival and morbidity. Primary graft nonfunction (PNF) is uncommon; however, it is one of the most serious and life‐threatening conditions in the immediate postoperative period. The risk factors associated with PNF and short‐term outcome have been previously reported, but there are no reports of long‐term follow‐up after retransplant for PNF. At our institution, 52 liver transplants had PNF (2.22%) among 2,341 orthotopic liver transplants in 2,130 patients from 1984 to 2003. PNF occurred more often in the retransplant setting. Female donors, donor age, donor days in the intensive care unit, cold ischemia time, and operating room time were significant factors for PNF. Patient as well as graft survival of retransplant for PNF was not different compared to retransplant for other causes. However, PNF for a second or third transplant did not demonstrate long‐term survival, and hospital mortality was 57%. In conclusion, retransplant for PNF in the initial transplant can achieve relatively good long‐term survival; however, if another transplant is needed in the setting of a second PNF, the third retransplant should probably not be done due to poor expected outcome. Liver Transpl 13:227–233, 2007.

Transplantation of highly differentiated immortalized human hepatocytes to treat acute liver failure.

BACKGROUND Temporary support of a damaged liver by a bioartificial liver (BAL) devise is a promising approach for the treatment of acute liver failure. Although human primary hepatocytes are an ideal source of hepatic function in BAL, shortage of human livers available for hepatocyte isolation is the limiting factor for the use of this modality. A clonal human hepatocyte cell line that can grow economically in culture and exhibit liver-specific functions should be an attractive solution to this problem. METHODS To test this alternative, primary human fetal hepatocytes were immortalized using Simian virus 40 large T antigen. To investigate the potential of the immortalized cells for BAL, we transplanted the cells into the spleen of adult rats and performed a 90% hepatectomy 12 hr later. RESULTS One of the cloned human liver cell lines, OUMS-29, showed highly differentiated liver functions. Intrasplenic transplanting of 20x10(6) OUMS-29 cells protected the animals from hyperammonemia and the associated hepatic encephalopathy. Survival was significantly prolonged in 90% of hepatectomized rats receiving OUMS-29 cells. CONCLUSIONS A highly differentiated immortalized human hepatocyte cell line, OUMS-29, was able to provide metabolic support during acute liver failure induced by 90% hepatectomy in rats. Essentially unlimited availability of OUMS-29 cells may be clinically useful for BAL treatment.

Risk of fractures after renal transplantation in the United States.

Background. Although it is known that the incidence of fracture events is increased in renal transplantation recipients, the timing and the factors associated with risk of fractures are less well understood. The objective of this study was to estimate the time to fracture in renal transplantation recipients and to determine whether risk was associated with patient and transplantation characteristics. Methods. Using the U. S. Renal Data System, we retrospectively studied 68,814 patients, who underwent renal transplantation between 1988 and 1998. Fractures were identified from International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes in billing data. Time to first fracture was modeled during the first 5 years posttransplant using the Kaplan-Meier method and Cox proportional hazards models. Results. Of the patients who underwent transplantation, 22.5% developed a fracture within 5 years. Woman (hazard ratio [HR] 1.36, P<0.0001), patients older than 45 years of age (HR 1.14, P<0.0001) especially older than 65 years (HR 1.69, P<0.0001), and whites (HR 1.28, P<0.0001) were at increased risk of a fracture. Additionally, receipt of a deceased donor kidney (HR 1.30, P<0.0001), increased human leukocyte antigen mismatches (HR 1.09, P<0.014), diabetes (HR 1.88, P<0.0001), pretransplant dialysis (HR 1.08, P<0.0001), and an aggressive induction immunosuppression regimen (HR 1.14, P<0.0001) all significantly increased risk of fracture events during the first 5 years. Conclusions. In addition to patient demographic features, donor factors, including suboptimal organ quality and the need for more intense immunosuppression, were associated with an increased risk of fractures during the first 5 years after a renal transplant.

Late acute rejection after liver transplantation impacts patient survival.

Abstract:  Hepatic allograft rejection still remains an important problem following liver transplantation. Early acute rejection, occurring within three months of transplant, is a common event and usually of lesser significance with respect to prognosis than other non‐immune‐related post‐transplant morbidities. However, little is known about late acute rejection (LAR) including factors affecting its occurrence and long‐term outcome. In this study, we analyzed LAR including the incidence, clinical risk factors, patient survival, and graft survival. LAR was defined as acute cellular rejection later than six months after liver transplant. Adult patients who had a minimum of 24 months of graft survival were included in this study. A total of 1604 case records of consecutive adult patients (over age 18 yr) who underwent liver transplant between 1985 and 2003 were reviewed. Of the 1604 patients, 305 (19.0%) developed LAR. Patients with primary diagnoses of autoimmune hepatitis, primary biliary cirrhosis, and primary sclerosing cholangitis had higher incidences of LAR, while patients with metabolic disease and retransplant had lower incidence of LAR (p = 0.0024). The LAR group had more female and younger recipients than the no LAR group (p = 0.0026, p = 0.0131, respectively). Patient survival as well as graft survival were significantly lower in the LAR group (p = 0.0083, p = 0.0075, respectively). PTLD was the only significant independent predictor of late rejection. The careful management and treatment of PTLD, especially immunosuppressive management, is important to prevent LAR, which is related to poorer patient survival.

Normal rat hepatic stellate cells respond to endotoxin in LBP-independent manner to produce inhibitor(s) of DNA synthesis in hepatocytes†

Endotoxin is implicated in the pathology of acute liver failure. The mechanisms of its actions on quiescent hepatic stellate cells (qHSCs) and their implications in hepatocyte injury are incompletely understood. We investigated effects of endotoxin (bacterial lipopolysaccharide; LPS) on qHSCs and subsequently on hepatocytes. After overnight culture following their isolation, qHSCs were incubated with or without endotoxin for 24 h. The cells and the culture supernatant were analyzed for cytokines and nitric oxide (NO) synthesis. The effects of qHSC‐conditioned media on hepatocytes were then determined. LPS increased inducible NO synthase expression, stimulated NO synthesis, and inhibited DNA synthesis in qHSCs. qHSC‐conditioned medium inhibited DNA synthesis in hepatocytes without affecting NO synthesis, while LPS (1–1,000 ng/ml)‐conditioned qHSC medium stimulated NO synthesis and caused further inhibition of DNA synthesis and apoptosis. These effects of LPS were more pronounced when qHSCs were incubated with serum, but not with LPS‐binding protein (LBP) although CD14 (a receptor for LPS‐LBP complex) was found in qHSCs. LPS stimulated the synthesis of TNF‐α, interleukin (IL)‐6, and IL‐1β but not of TGF‐β in qHSCs. Individually or together, L‐NG‐monomethylarginine and antibodies to IL‐1β, IL‐6, and TNF‐α only partly reversed qHSC + LPS‐conditioned medium‐induced inhibition of DNA synthesis in hepatocytes. These results suggest that the effects of LPS on qHSCs are novel, occurring without the aid of LBP/CD14. They also indicate that other factors, in addition to NO, TGF‐β, TNF‐α, IL‐1β, and IL‐6 are involved in the mechanisms of the growth inhibitory effects of qHSCs on hepatocytes.

Endothelin stimulates transforming growth factor-β1 and collagen synthesis in stellate cells from control but not cirrhotic rat liver

Interactions between hepatic stellate cells and endothelin-1 are implicated in liver fibrosis. We determined endothelin-1, its receptors and its effects on the synthesis of a fibrogenic agent transforming growth factor (TGF)-beta1 and collagen in stellate cells from control and CCl(4)-induced cirrhotic rats. The basal synthesis of endothelin-1, TGF-beta1 and collagen was much higher in cirrhotic stellate cells than in control cells. Endothelin-1 stimulated TGF-beta1 and collagen synthesis via endothelin ET(A) and endothelin ET(B) receptors, respectively, in control stellate cells, but did not elicit these effects in the cirrhotic cells despite increased density of the respective receptor subtypes in them. These results indicate that the actions of endothelin-1 on stellate cells may be an important physiological mechanism in maintenance of hepatic architecture. However, inability of endothelin-1 to stimulate TGF-beta1 and collagen synthesis in cirrhotic stellate cells suggests that it does not influence fibrogenic activity by direct action on them probably because the processes are already maximally activated.

Inhibition of DNA synthesis in cultured hepatocytes by endotoxin-conditioned medium of activated stellate cells is transforming growth factor-β and nitric oxide-independent

Activated hepatic stellate cells play a major role in the pathophysiology of chronic liver disease. They can influence the metabolism of hepatocytes by producing a variety of cytokines and growth factors. Upon stimulation with endotoxin, stellate cells also synthesize nitric oxide (NO), a potent mediator of growth of several cell types including hepatocytes. We investigated the effect of serum‐free medium conditioned by activated stellate cells in the absence and presence of endotoxin on NO and DNA synthesis in hepatocytes. Stellate cells and hepatocytes were isolated by enzymatic digestion of the liver. Stellate cells were cultured for 10 days after which the majority exhibited α‐smooth muscle actin (a marker for activated cells); hepatocytes were used after overnight culture. While the medium conditioned by stellate cells in the absence of endotoxin stimulated DNA synthesis in hepatocytes, medium conditioned in its presence inhibited this process in an endotoxin concentration‐dependent manner (10–1000 ng ml−1). Endotoxin‐conditioned stellate cell medium also stimulated NO synthesis in hepatocytes; the effect was consistent with increased protein and mRNA expression of inducible NO synthase (iNOS). However, inhibition of DNA synthesis in hepatocytes caused by endotoxin‐conditioned stellate cell medium was unaffected by the NOS inhibitor, L‐NG‐monomethylarginine (L‐NMMA), guanylyl cyclase inhibitor 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one (ODQ), and neutralizing antibodies for TGF‐β, IL‐1β, IL‐6 and TNF‐α. These results indicate that factors other than these cytokines produced by activated stellate cells upon stimulation with endotoxin or by hepatocytes challenged with endotoxin‐conditioned stellate cell medium inhibit DNA synthesis in hepatocytes.

Bone Marrow-derived Endothelial Progenitor Cells and Endothelial Cells May Contribute to Endothelial Repair in the Kidney Immediately After Ischemia-Reperfusion

In ischemic acute kidney injury, renal blood flow is decreased. We have previously shown that reperfused, transplanted kidneys exhibited ischemic injury to vascular endothelium and that preservation of peritubular capillary endothelial integrity may be critical to recovery from ischemic injury. We hypothesized that bone marrow–derived (BMD) endothelial progenitor cells (EPCs) might play an important role in renal functional recovery after ischemia. We tested this hypothesis in recipients of cadaveric renal allografts before and for 2 weeks after transplantation. We found that the numbers of circulating CD34-positive EPCs and CD146-positive endothelial cells (ECs) decreased immediately after ischemia–reperfusion. In renal allograft tissues obtained 1 hr after reperfusion, CD34-positive cells were more frequently observed along the endothelial lining of peritubular capillaries compared with non-ischemic controls. Moreover, 0–17.5% of peritubular capillary ECs were of recipient origin. In contrast, only 0.1–0.7% of tubule cells were of recipient origin. Repeat graft biopsy samples obtained 35 and 73 days after transplant did not contain capillary ECs of recipient origin, whereas 1.4% and 12.1% of tubule cells, respectively, were of recipient origin. These findings suggest that BMD EPCs and ECs may contribute to en-dothelial repair immediately after ischemia–reperfusion.

Acute graft-versus-host disease after liver transplantation: Role of withdrawal of immunosuppression in therapeutic management

Graft‐versus‐host disease (GVHD) after liver transplantation is rare but associated with a very high mortality (over 85%). Most treatments focus on increasing immunosuppression, addition of antibody preparations such as OKT3 and antithymocyte globulin to eliminate the donor lymphocytes, and supporting myelopoiesis by use of cytokines. However, the results are very poor. We reasoned that a better therapeutic approach would be to reduce the immunosuppression and allow the patients immune system an opportunity to reject the allograft donor T cells. We tested this novel therapeutic approach in 3 patients diagnosed with GVHD. Two patients had rapid loss of donor T cell chimerism and resolution of their symptoms. The other patient continued to progress to severe GVHD and died. The patients who responded to withdrawal of immunosuppression had a later onset of symptoms and a lower level of donor CD3+ T cells at the start of treatment. We conclude that larger studies are needed to further evaluate these results and to determine what factors may affect the likelihood that a patient may respond to this approach. Liver Transpl 13:157–161, 2007.

Outcome of induction immunosuppression for liver transplantation comparing anti‐thymocyte globulin, daclizumab, and corticosteroid

In addition to standard corticosteroid induction, anti‐thymocyte globulin (ATG) or daclizumab as induction immunosuppression has been reported for liver transplantation. However, the effects and long‐term outcomes of antibody induction therapy are not well known, especially for hepatitis C (HCV). The United Network for Organ Sharing (UNOS) database was utilized to analyze 16 898 adult primary liver transplant patients who received ATG alone (n = 452), ATG and steroids (ATG + S) (n = 1758), daclizumab alone (n = 683), or steroid alone (n = 14 005), listed as induction immunosuppression. Graft and patient survival, and donor and recipient factors for survival were analyzed for HCV and all liver diseases. For patients with HCV, ATG + S had significantly inferior graft survival compared with daclizumab (P = 0.01) and steroids (P = 0.03). The Cox proportional hazards model also showed that ATG + S was a marginal risk factor for graft failure (P = 0.05). On the other hand, for patients with all the liver diseases, graft and patient survival were not significantly different between induction regimens. ATG induction appeared to be preferentially used in patients with renal dysfunction, with improvement in renal function after liver transplantation. Thus, ATG induction can be used for patients with renal dysfunction in non‐HCV diseases. Daclizumab induction achieved satisfactory short‐term and long‐term outcomes of liver transplantation in all the liver diseases including HCV disease.