Long-term comparison of tacrolimus versus cyclosporine in liver transplantation. The US FK Study Group

Targeted delivery of tacrolimus to T cells by pH-responsive aptamer-chitosan- poly(lactic-co-glycolic acid) nanocomplex

Tacrolimus (TAC) acts as an inhibitor of calcineurin, which inhibits the production of interleukin-2. In this study, we aimed to design a targeted delivery platform with poly (lactide-co-glycolide; PLGA) nanoparticles modified with chitosan (CS) and CD8AP17s aptamer (Apt). MOLT-4 cells as CD8 positive and JURKAT cells as CD negative were adopted to investigate the efficacy of the proposed delivery system in vitro. The particle size and Ζ potential of the TAC-PLGA-CS-Apt nanocomplex were 345 nm and 13.7 mV, respectively. Release study showed an efficient TAC release from complex in citrate buffer (pH 5.5). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that TAC-PLGA-CS-Apt nanocomplex was highly selective toward MOLT-4 cells. Complex increased the cellular uptake of TAC in MOLT-4 cells (target) while reducing its cytotoxicity in JURKAT cells (nontarget). Our study showed that complex nanoconjugate could efficiently deliver TAC into MOLT-4 cells as a model of cytotoxic T cell and it could be considered as a potential candidate for TAC delivery.

The adverse pharmacology of calcineurin inhibitors and their impact on hepatitis C recurrence after liver transplantation: implications for clinical practice

Calcineurin inhibitors are widely used as maintenance immunosuppressants in solid-organ transplantation to minimize the risk of allograft rejection. Although the use of these agents has transformed the outcomes for patient and graft survival, this has come at a cost, notably the well-known adverse events of nephrotoxicity and metabolic abnormalities, to name a few. Over the last decade, tremendous interest has also focused on the impact of these medications on the replication of hepatitis C virus (HCV), with cyclosporine in particular having a negative effect on viral replication in vitro. Although small retrospective studies suggested that there may be a beneficial effect with cyclosporine on the progression of recurrent HCV and response to interferon, these findings have not been validated in several well-designed randomized controlled trial studies. The authors will review the pharmacology and pharmacokinetics of these well-known drugs and discuss the impact of these medications on the natural history of HCV recurrence after liver transplantation.

Chronic rejection of the liver: the role of immunosuppression

Liver transplantation is now widely recognised as an effective treatment option for patients with advanced liver disease. Many units now achieve greater than 85% survival at 1 year, with the majority of patients having a high quality of life. The maintenance of a high quality of life requires careful clinical management to ensure that the continued maintenance of excellent liver graft function is not achieved at the expense of immunosuppressive drug complications or morbidity. Acute liver rejection will occur in between 30 to 45% of patients, although with modern immunosuppressive protocols, usually combining one of the calcineurin agents, either cyclosporin or tacrolimus, with both azathioprine and corticosteroids (prednisolone) ensures that relatively few grafts are lost from severe acute rejection. While the incidence and severity of acute rejection may be one factor in raising the risk of chronic rejection, it may not be the principal one in many patients. It is important to recognise that the frequency of rejection also varies with the primary underlying liver disease, with patients with hepatitis B or alcoholic liver disease having relatively low rejection rates, compared with patients with primary biliary cirrhosis (PBC) or primary sclerosing cholangitis (PSC), which range between 20 to 70%. Chronic rejection will account for some 5% of grafts lost in the first 3 to 5 years. Indeed, there is some evidence that the incidence of chronic rejection is actually declining over the past few years. While the reason for this apparent decline is uncertain, and it could relate to better immunosuppression management, or more likely to the growing recognition that chronic graft dysfunction may be due to recurrent liver disease, such as autoimmune hepatitis, PBC, PSC, or recurrent hepatitis C. The differentiation of recurrent primary liver disease from chronic rejection can prove to be very difficult in clinical practice. Thus, the clinician must carefully monitor liver and graft function, evaluate any biochemical changes, and try to reach a clear diagnosis before considering any modification of immunosuppressive schedules.

Impact of hepatitis C viral infection in primary cadaveric liver allograft versus primary living-donor allograft in 100 consecutive liver transplant recipients receiving tacrolimus

BACKGROUND

There has been concern that adult living-donor liver transplantation (LLTx) for hepatitis C virus (HCV) infection may lead to recurrent disease that is more severe compared with the results of cadaveric LTx (CLTx), because the smaller sized graft in LLTx regenerates and may increase viral replication. This study examines the survival outcome and HCV recurrence in CLTx versus LLTx performed at a single institution.

METHOD

A total of 100 consecutive adult recipients (75 men and 25 women; mean age 49.9+/-8.4 years) of LTx (65 CLTxs and 35 LLTxs performed July 2000-July 2002) who tested positive for HCV by polymerase chain reaction were examined retrospectively until October 2003. All patients received tacrolimus-based immunosuppression with mycophenolate mofetil and steroids.

RESULTS

The overall actual patient survival was 85% (83.1% for CLTx vs. 88.6% for LLTx). The 39-month Kaplan-Meier actuarial patient survivals were 75.1% for CLTx and 88.6% for LLTx. Of 15 deaths, 6 were the result of recurrent HCV (five CLTxs and one LLTx), and of 10 retransplants, 2 were related to recurrent HCV (one CLTx and one LLTx). The rates of recurrence were 72.3% and 77.1%, the hepatitis activity indices were 5.4 + 2.4 and 6.2 + 2.8, the fibrosis scores were 1.4+/-1.4 and 1.5+/-1.3, and the times to recurrence were 318+/-269 days and 394+/-250 days for CLTx and LLTx, respectively. None of the differences between the two groups were significant.

CONCLUSION

No detrimental effect of HCV infection was found in LLTx recipients when compared with contemporaneous CLTx recipients. Patient survival, graft survival, rate of HCV recurrence, severity of HCV recurrence, graft loss from HCV, and interval for recurrence in CLTx and LLTx were similar.

Liver transplantation in the UK

INTRODUCTION

This paper provides a review of the practice of liver transplantation with the main emphasis on UK practice and indications for transplantation.

REFERRAL AND ASSESSMENT

This section reviews the process of referral and assessment of patients with liver disease with reference to UK practice.

DONOR ORGANS

The practice of brainstem death and cadaveric organ donation is peculiar to individual countries and rates of donation and potential areas of improvement are addressed.

OPERATIVE TECHNIQUE

The technical innovations that have led to liver transplantation becoming a semi-elective procedure are reviewed. Specific emphasis is made to the role of liver reduction and splitting and living related liver transplantation and how this impacts on UK practice are reviewed. The complications of liver transplan-tation are also reviewed with reference to our own unit. Immunosuppression:The evolution of immunosuppression and its impact on liver transplantation are reviewed with some reference to future protocols.

RETRANSPLANTATION

The role of retransplantation is reviewed.

OUTCOME AND SURVIVAL

The results of liver transplantation are reviewed with specific emphasis on our own experience.

FUTURE

The future of liver transplantation is addressed.

Liver transplantation in the UK

INTRODUCTION

This paper provides a review of the practice of liver transplantation with the main emphasis on UK practice and indications for transplantation.

REFERRAL AND ASSESSMENT

This section reviews the process of referral and assessment of patients with liver disease with reference to UK practice.

DONOR ORGANS

The practice of brainstem death and cadaveric organ donation is peculiar to individual countries and rates of donation and potential areas of improvement are addressed.

OPERATIVE TECHNIQUE

The technical innovations that have led to liver transplantation becoming a semi-elective procedure are reviewed. Specific emphasis is made to the role of liver reduction and splitting and living related liver transplantation and how this impacts on UK practice are reviewed. The complications of liver transplan-tation are also reviewed with reference to our own unit. Immunosuppression:The evolution of immunosuppression and its impact on liver transplantation are reviewed with some reference to future protocols.

RETRANSPLANTATION

The role of retransplantation is reviewed.

OUTCOME AND SURVIVAL

The results of liver transplantation are reviewed with specific emphasis on our own experience.

FUTURE

The future of liver transplantation is addressed.

What have we learned about primary liver transplantation under tacrolimus immunosuppression? Long-term follow-up of the first 1000 patients

OBJECTIVE

To summarize the long-term efficacy and safety of tacrolimus in orthotopic liver transplant (OLT) recipients, as well as to examine the factors that influence long-term morbidity and mortality rates.

BACKGROUND

Tacrolimus (FK506, Prograf) was introduced as primary immunosuppression for primary liver transplantation in 1989; many subsequent trials have verified the association of tacrolimus with decreased rates of acute rejection and steroid-resistant rejection after OLT. Cumulative experience with tacrolimus has also defined its short- and intermediate-term toxicity.

METHODS

One thousand consecutive patients undergoing primary OLT at a single center from August 1989 to December 1992, under tacrolimus immunosuppression, were followed until January 1999. Patients were categorized by age. Mean follow-up was 93.4+/-11 months after OLT. Patient survival, graft survival (with corresponding causes of death and retransplantation), and rejection rates (and corresponding doses of immunosuppression) were examined as efficacy parameters. Hypertension, renal function, incidence of malignancies, incidence of diabetes, and other toxicities were examined as safety parameters.

RESULTS

Actual 6-year overall patient survival rate was 68.1% and graft survival rate was 62.5%, with significant differences in the patterns of survival among the different age groups. After the first post-OLT year, infection, recurrence of disease, de novo malignancies, and cardiovascular events were the main causes of graft loss and death during the long-term follow-up. Graft loss related to either acute or chronic rejection was rare. The rate of acute rejection beyond 2 years was approximately 3% per year, and most were steroid-responsive. Approximately 70% of the patients were receiving tacrolimus monotherapy beyond year 1; at the latest follow-up, 74.2% were maintained on tacrolimus alone. In 6.1% of the survivors, end-stage renal disease developed during the follow-up period, requiring either dialysis or kidney transplantation. Hyperkalemia and hypertension was observed in approximately one third of the patients. Insulin-dependent diabetes mellitus (including patients who had diabetes before the transplant) was observed in 14% in year 1, dropping to 11% in year 7. In 82 patients, de novo malignancies developed; in 41 patients, lymphoproliferative disorders developed during the entire follow-up period.

CONCLUSIONS

Long-term patient and graft survival rates are excellent under tacrolimus immunosuppression. Pediatric patients have a better long-term outcome than adults, in part because of the limited recurrence of the original disease, which was the most common cause of late graft loss (other than patient death, most commonly the result of late de novo malignancies and cardiovascular events). Graft loss from late rejection was rare.