Sirolimus as primary immunosuppression in liver transplantation is not associated with hepatic artery or wound complications

Basics and Art of Immunosuppression in Liver Transplantation

Liver transplantation is one of the most challenging areas in the medical field. Despite that, it has already been established as a standard treatment option, especially in decompensated cirrhosis and selected cases of hepatocellular carcinoma and acute liver failure. Complications due to graft rejection, including mortality and morbidity, have greatly improved over time due to better immunosuppressive agents and management protocols. Currently, immunosuppression in liver transplant patients makes use of the best possible combinations of effective agents to achieve optimal immunosuppression for long-term graft survival. Induction agents are no longer used routinely, and the aim is to provide minimal immunosuppression in the maintenance phase. Currently available immunosuppressive agents are mainly classified as biological and pharmacological agents. Though the protocols may vary among the centers and over time, the basics of effective use usually remain similar. Most protocols use the combination of multiple agents with different mechanisms of action to reduce the dose and minimize the side effects. Along with the improvement in operative and perioperative techniques, this art of immunosuppression has contributed to the recent progress made in the outcomes of liver transplants. In this review, we will discuss the various types of immunosuppressive agents currently in use, the different protocols of immunosuppression used, and the art of optimal use for achieving maximum immunosuppression without increasing toxicity. We will also discuss the practical aspects of various immunosuppression regimens, including drug monitoring, and briefly discuss the concepts of immunosuppression minimization and withdrawal.

Asian Pacific Association for the Study of the Liver clinical practice guidelines on liver transplantation

Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.

The Role of mTOR Inhibitors after Liver Transplantation for Hepatocellular Carcinoma

Liver transplantation is a treatment option for nonresectable patients with early-stage HCC, with more significant advantages when Milan criteria are fulfilled. An immunosuppressive regimen is required to reduce the risk of graft rejection after transplantation, and CNIs represent the drugs of choice in this setting. However, their inhibitory effect on T-cell activity accounts for a higher risk of tumour regrowth. mTOR inhibitors (mTORi) have been introduced as an alternative immunosuppressive approach to conventional CNI-based regimens to address both immunosuppression and cancer control. The PI3K-AKT-mTOR signalling pathway regulates protein translation, cell growth, and metabolism, and the pathway is frequently deregulated in human tumours. Several studies have suggested the role of mTORi in reducing HCC progression after LT, accounting for a lower recurrence rate. Furthermore, mTOR immunosuppression controls the renal damage associated with CNI exposure. Conversion to mTOR inhibitors is associated with stabilizing and recovering renal dysfunction, suggesting an essential renoprotective effect. Limitations in this therapeutic approach are related to their negative impact on lipid and glucose metabolism as well as on proteinuria development and wound healing. This review aims to summarize the roles of mTORi in managing patients with HCC undergoing LT. Strategies to overcome common adverse effects are also proposed.

Postoperative negative-pressure incision therapy after liver transplant (PONILITRANS study): A randomized controlled trial

BACKGROUND

Postoperative complications of surgical incisions are frequent in liver transplantation. However, evidence justifying the use of incisional negative pressure wound therapy to improve surgical wound outcomes remains limited.

METHODS

Participating patients were randomly assigned to receive incisional negative pressure wound therapy or standard surgical dressing on the closed surgical incision of the liver transplantation. The primary endpoint was surgical site infection incidence 30 days postoperatively. The secondary endpoints included surgical site events (ie, surgical site infection, dehiscence, hematoma, and seroma) and wound quality of life.

RESULTS

Between December 2018 and September 2021, 108 patients (54 in the incisional negative pressure wound therapy group and 54 in the control group) were enrolled in this study. The incidence of surgical site infection at 30 days postoperatively was 7.4% in the treatment group and 13% in the control group (P = .34). The rate of surgical site events was similar in the treatment in the and control group (27.8% vs 29.6%, P = .83). In relation to wound quality of life, the mean score was 75.20 ± 7.27 in the incisional negative pressure wound therapy group and 72.82 ± 10.57 in the control group (P = .23).

CONCLUSION

The prophylactic use of negative pressure wound therapy on primarily closed incisions did not significantly reduce incisional surgical site infection and surgical site event rates after liver transplantation compared with standard surgical dressings.

Is there a procoagulant state long-term after lung transplantation? A prospective study

BACKGROUND

Venous thromboembolism (VTE) is a major complication after lung transplantation (LT). However, its pathophysiology remains unknown, and coagulation profiles have yet to be described.

OBJECTIVE

The aim of this study was to longitudinally assess coagulation status after LT.

METHODS

We performed a prospective study and described the coagulation profiles of 48 patients at 5 different time-points: before LT and at 24-72 h, 2 weeks, 4 months, and 1 year after LT.

RESULTS

At baseline, almost all analyzed coagulation factors were within the normal range, except for FVIII, which was above the normal range. Von Willebrand factor (vWF) and FVIII were increased after LT and remained high at 1 year after transplantation. The cumulative incidence of VTE was 22.9%. Patients who developed VTE had higher FVIII activity 2 weeks after LT.

CONCLUSIONS

This is the first study to describe coagulation profiles up to 1 year after LT. We show that most markers of a procoagulant state normalize at 2 weeks after LT, but that values of FVIII and vWF remain abnormal at 1 year. This problem has received little attention in the literature. Larger studies are necessary to confirm the results and to design appropriate prophylactic strategies.

The Role of Rapamycin in Healthspan Extension via the Delay of Organ Aging

Aging can not only shorten a healthy lifespan, but can also lead to multi-organ dysfunction and failure. Anti-aging is a complex and worldwide conundrum for eliminating the various pathologies of senility. The past decade has seen great progress in the understanding of the aging-associated signaling pathways and their application for developing anti-aging approaches. Currently, some drugs can improve quality of life. The activation of mammalian target of rapamycin (mTOR) signaling is one of the core and detrimental mechanisms related to aging; rapamycin can reduce the rate of aging, improve age-related diseases by inhibiting the mTOR pathway, and prolong lifespan and healthspan effectively. However, the current evidence for rapamycin in lifespan extension and organ aging is fragmented and scattered. In this review, we summarize the efficacy and safety of rapamycin in prolonging a healthy lifespan by systematically alleviating aging in multiple organ systems, i.e., the nervous, urinary, digestive, circulatory, motor, respiratory, endocrine, reproductive, integumentary and immune systems, to provide a theoretical basis for the future clinical application of rapamycin in anti-aging.

Immunosuppression in liver transplant

The increasing potency of immunosuppression (IS) agents resulted in significantly decreased rates of steroid resistant rejection and rejection related graft loss in liver transplantation (LT). Currently, more than two thirds of late mortality after LT is unrelated to graft function. However, the increased benefit of more potent IS drugs, coupled with the prolonged survival of transplant recipients led to longer patients exposure to these drugs and their unwanted adverse effects, creating a double-edged sword. In this article the authors describe the mechanism of action and the adverse effects of the most commonly used immunosuppressed drugs, and the most commonly used IS regimens for both induction and maintenance regimens. The balance between the ideal IS regimen to prevent rejection and the need to minimize the dose of IS drugs in order to prevent the adverse effects related to its use requires the knowledge of the science and the experience with the art of medicine. The different protocols aimed at protecting renal function and preventing the development of de novo cancer and metabolic syndrome are discussed here. The main causes of mortality late after liver transplant are associated with prolonged use of IS medications, and clear evidence exists about over-immunosuppression of recipients of liver transplant. The current status of strategies of IS minimization and withdrawal are reviewed in this article, with evaluation of its benefits and pitfalls.

Metabolic and Renal Effects of Mammalian Target of Rapamycin Inhibitors Treatment After Liver Transplantation: Real-Life Single-Center Experience

BACKGROUND

Mammalian target of rapamycin (mTOR) inhibitors following liver transplantation (LT) are used to minimize calcineurin inhibitor (CNI)-related nephrotoxicity. Data about metabolic effects of mTOR inhibitors are still limited.

AIM

This study aims to determine the renal and metabolic effects of different mTOR inhibitor-based protocols in real-life LT patients.

METHODS

This is a retrospective cohort study of patients treated with mTOR inhibitors after LT. Demographics, treatment protocols, glomerular filtration rate (GFR), and metabolic parameters were collected over a period of 4 years. Initiation of blood pressure (BP), diabetes mellitus, and lipid medications was also noted.

RESULTS

Fifty-two LT recipients received mTOR inhibitors. GFR improved significantly (by 1.96 mL/min/year), with greater improvement in patients with baseline renal dysfunction (+13.3 mL/min vs +4.5 mL/min at 3 years). Conversion to an mTOR inhibitor during the first post-transplant year resulted in a more durable improvement in GFR (for 4 years vs only 1 year for later conversion).No significant weight gain or new-onset diabetes mellitus was observed. However, there was some increase in total cholesterol (+7 mg/dL) and blood pressure (+2 mm Hg during the third year and +8 mm Hg in the fourth years), followed by initiation of lipid-lowering and BP medications in 25% and 13% of patients, respectively.

CONCLUSIONS

Treatment with an mTOR inhibitor following LT resulted in improved kidney functions without significant negative metabolic effects such as weight gain or new-onset diabetes mellitus. This makes mTOR inhibitors a valuable immunosuppressive option in the face of the growing incidence of nonalcoholic steatohepatitis as a leading cause for LT.

International Liver Transplantation Society Consensus Statement on Immunosuppression in Liver Transplant Recipients

Effective immunosupression management is central to achieving optimal outcomes in liver transplant recipients. Current immunosuppression regimens and agents are highly effective in minimizing graft loss due to acute and chronic rejection but can also produce a substantial array of toxicities. The utilization of immunosuppression varies widely, contributing to the wide disparities in posttransplant outcomes reported between transplant centers. The International Liver Transplantation Society (ILTS) convened a consensus conference, comprised of a global panel of expert hepatologists, transplant surgeons, nephrologists, and pharmacologists to review the literature and experience pertaining to immunosuppression management to develop guidelines on key aspects of immunosuppression. The consensus findings and recommendations of the ILTS Consensus guidelines on immunosuppression in liver transplant recipients are presented in this article.

Treatment with mTOR inhibitors after liver transplantation enables a sustained increase in regulatory T-cells while preserving their suppressive capacity

BACKGROUND

The mammalian targets of rapamycin (mTOR) inhibitors (sirolimus [SRL] and everolimus [EVR]) are used after transplantation for their immunosuppressive activity. Regulatory T-cells (Tregs) play a crucial role in immune tolerance. mTOR inhibitors appear to preserve Tregs, unlike Tacrolimus (Tac).

AIM

The aim of this study was to evaluate the number and function of Tregs in liver transplant recipients before and after conversion from Tac to mTOR inhibitors.

METHODS

Fifteen patients with stable graft function where converted to SRL (n=5) or EVR (n=10). Tregs (CD4⁺ CD25⁺ FoxP3⁺ CD127^low) number and activity were analysed prospectively in blood cells using flow cytometry, and functional assay.

RESULTS

Patients of both groups displayed a sustained rise in Treg levels after introduction of mTOR inhibitors (Treg levels at 3 months: 6.45±0.38% of CD4 T-cells, vs. baseline level of 3.61±0.37%, P<0.001; mean fold increase 2.04±0.73). In SRL group, 3-month Treg levels were 6.01±0.53 vs. 3.79±0.39; P=0.037, while in EVR group they were 6.63±0.67 vs. 3.54±0.51; P=0.001. By contrast, no statistical change was observed in an unconverted Tac control group. Tregs also preserved their functional ability to suppress activated T-cells.

CONCLUSION

These results suggest that mTOR inhibitors induce a significant increase in Tregs while maintaining suppressive activity after LT.

Immunosuppression in the pediatric transplant recipient

The field of pediatric solid-organ transplantation has significantly evolved since its beginnings in the early 20^th century. As advancements have led to the development of innovative surgical techniques and novel medication regimens, transplantation has now become a routine practice leading to an increase in the rates of organ recipients worldwide. The care of pediatric solid-organ transplant recipients differs from adults in several areas not only due to technically challenging surgeries, but mostly due to the complexity of their immunosuppression management. Although there is large variation of pediatric immunosuppression regimens worldwide, the use of calcineurin inhibitors, either tacrolimus or cyclosporine, still forms the backbone of immunosuppression regimens after solid-organ transplantation. Both medications are relatively well tolerated but are known to have long-term side effects, especially nephrotoxicity and neurotoxicity. The goal of care in long-term pediatric survivors of solid-organ transplant now aims to safely minimize exposure to immunosuppression and to achieve long-term graft tolerance.

Activation of Autophagy by Everolimus Confers Hepatoprotection Against Ischemia-Reperfusion Injury

As the criteria for liver donation have been extended to include marginal donors, liver grafts are becoming particularly vulnerable to hepatic ischemia-reperfusion injury (IRI). However, no specific measures have been validated to ameliorate hepatic IRI. In this article, we explored whether everolimus has protective effects against hepatic IRI in relation with autophagy. The effects of everolimus were investigated in both in vitro and in vivo hepatic IRI models. Mouse hepatocyte AML12 cells and BALB/c mice were utilized for the establishment of each model. In the IRI-induced AML12 cells, everolimus treatment increased the expressions of autophagic markers (microtubule-associated protein 1 light chain 3 and p62) and decreased pro-apoptotic proteins (cleaved caspase 3 and cleaved poly-ADP ribose polymerase). The blockage of autophagy, using either bafilomycin A1 or si-autophagy-related protein 5, abrogated these anti-apoptosis effects of everolimus. Subsequently, everolimus administration to the hepatic IRI-induced mice provided hepatoprotective effects in terms of (1) decreasing the expressions of pro-apoptotic proteins, (2) inhibiting the release of pro-inflammatory cytokines (IL-6 and tumor necrosis factor-α), (3) reducing elevated liver enzymes (aspartate transaminase, alanine transaminase, and ammonia), and (4) restoring liver histopathology. These findings suggest that everolimus protects the liver against hepatic IRI by way of activating autophagy, and thus could be a potential therapeutic agent for hepatic IRI.

New Antiproliferative Immunosuppressive Agents

Since the early 1980s, the combination of cyclosporine, azathioprine, and prednisone has been the mainstay tripledrug immunosuppressive regimen used in transplantation. However, advances in drug research, design, and development have allowed for the introduction of new agents that have greatly increased the number of immunosuppressive agents available for use in transplant recipients. Particularly, the newer antiproliferative immunosuppressive drugs (agents that directly inhibit the proliferation of T and B lymphocytes) have had an important impact on patient outcomes posttransplant. These agents are mycophenolate mofetil and sirolimus.

Delayed primary closure and the incidence of surgical complications in pediatric liver transplant recipients

PURPOSE

The purpose of this study was to analyze the general surgical complications in pediatric liver transplant recipients and the safety of delayed primary closure at a single tertiary center.

METHODS

A retrospective review of all liver transplant recipients between April 1986 and May 2014 was performed. All general and gastrointestinal complications were recorded and analyzed. The incidence and risk of these complications were compared between children who had a primary versus those who had a delayed closure, with or without the use of Surgisis®, of their abdomen.

RESULTS

242 patients underwent 281 liver transplants. The median age of the children was 31months. Whole (77), reduced size (91), split (96), and living related grafts (17) were used. General surgical complications were observed in 33 cases (11.7%). 135 cases underwent delayed primary closure (DPC) of their abdomen, 35 with Surgisis®. Patients with biliary atresia had a higher rate (4.6%) of bowel perforation (p=0.013). The majority of complications occurred within 3months of transplantation.

CONCLUSION

General surgical complications postpediatric liver transplantation were common but usually not life threatening. Delayed primary closure was safe, had no significant long-term issues, and was not associated with higher incidence of wound related complications.

The benefit of sirolimus maintenance immunosuppression and rabbit antithymocyte globulin induction in liver transplant recipients that develop acute kidney injury in the early postoperative period

Published data are limited describing renal outcomes in orthotopic liver transplant (OLT) recipients prescribed sirolimus (SRL) maintenance immunosuppression (MIS) and rabbit antithymocyte globulin (rATG) induction. We investigated whether SRL MIS and rATG induction facilitated recovery of acute kidney injury in the early postoperative period. This retrospective descriptive study screened 308 consecutive OLTs performed between 2006 and 2009. All patients received rATG induction with steroid avoidance. MIS consisted of SRL or TAC with mycophenolate mofetil. A total of 197 patients were included: 168 (85%) received TAC and 29 (15%) received SRL for a median of 365 days. Demographics were similar between groups except for a higher incidence of pretransplant renal dysfunction in the SRL recipients (SRL 59% versus TAC 21%; P < 0.05). The eGFR was significantly (P < 0.05) higher for all time points in the TAC group with the exception of month 2. However, improvement in eGFR was significantly (P < 0.05) greater in the SRL group postoperatively. Our study suggests that rATG induction and SRL maintenance immunosuppression facilitate renal recovery for liver transplant recipients that develop acute kidney injury in the early postoperative period.

A retrospective 15-year review: survival advantage after switching to sirolimus in hepatitis C virus infected liver graft recipients

BACKGROUND

The use of sirolimus-based immune suppression in liver transplantation, particularly in hepatitis C virus (HCV)-infected recipients, remains contentious. There is some evidence that sirolimus retards hepatic fibrosis, is renal sparing and may be of benefit in preventing hepatocellular carcinoma (HCC) recurrence. Sirolimus has not been adopted by many transplant centres because of persistent concerns regarding an increased risk of hepatic artery thrombosis, graft loss and death with de novo sirolimus.

AIM

To review the impact of switching to sirolimus monotherapy in HCV-infected liver recipients with respect to survival, graft loss and hepatic fibrosis.

METHODS

A retrospective review of 190 patients from a single centre undergoing first liver transplantation for HCV over 15 years. 113 patients were switched from calcineurin inhibitor (CNI)-based therapy to low-dose sirolimus monotherapy at a median of 15 months after transplantation for HCV-related fibrosis (72%), renal impairment (14%) or high-risk HCC (5%).

RESULTS

Patients switched to sirolimus had improved survival (P < 0.001) and slower progression to cirrhosis (P = 0.001). In patients with HCC (n = 91), sirolimus duration rather than strategy was an independent predictor of survival (P = 0.001) and extended time to HCC recurrence (33 vs. 16 months). Patients switched for renal dysfunction showed improvement in serum creatinine (140-108 μmol/L, P = 0.001). Those remaining on CNI-therapy were more likely to develop post-transplant diabetes (P = 0.03).

CONCLUSION

These data suggest selective switching to low-dose sirolimus monotherapy in HCV-positive liver recipients improves clinical outcome.

Everolimus immunosuppression reduces the serum expression of fibrosis markers in liver transplant recipients

AIM: To evaluate the expression of serum fibrosis markers in liver transplantation (LT) recipients on everolimus monotherapy compared to patients on an anti-calcineurin regimen.

METHODS: This cross-sectional case-control study included LT patients on everolimus monotherapy (cases) (E) (n = 30) and matched controls on an anti-calcineurin regimen (calcineurin inhibitors, CNI), paired by etiology of liver disease and time since LT (n = 30). Clinical characteristics, blood tests and elastography were collected. Serum levels of transforming growth factor-β (TGF-β), angiopoietin-1, tumor necrosis factor (TNF), platelet derived growth factor, amino-terminal propeptide of type III procollagen (PIIINP), hyaluronic acid (HA), VCM-1 (ng/mL), interleukin (IL)-10, interferon-inducible protein 10 (IP-10), vascular endothelial growth factor and hepatocyte growth factor (HGF) (pg/mL) were determined by enzyme-linked immunosorbent assay. Expression of these markers between E and CNI was compared. Stratified analysis was done according to factors that may influence liver fibrosis. Variables are described with medians (interquartillic range) or percentages.

RESULTS: A total of 60 patients [age: 59 (49-64), hepatitis C virus (HCV): n = 21 (35%), time from LT: 73 mo (16-105)] were included. Patients had been on everolimus for a median of 15 mo. No differences in inflammatory activity, APRI test or liver elastography were found between the groups. No significant differences were observed between the groups in serum levels of PIIINP, metalloproteinase type = 1, angiopoietin, HGF, IP-10, TNF-α, IL-10 and vascular cell adhesion molecule. Patients on E had a lower expression of TGF-β [E: 12.7 (3.7-133.6), CNI: 152.5 (14.4-333.2), P = 0.009] and HA [E: 702.89 (329.4-838.2), CNI: 1513.6 (691.9-1951.4), P = 0.001] than those on CNI. This difference was maintained in the stratified analysis when recipient age is more than 50 years (TFG-β1: P = 0.06; HA: P = 0.005), in patients without active neoplasia (TFG-β1, P = 0.009; HA: P = 0.01), according to time since LT (> than 5 years, TFG-β1: P = 0.001; HA: P = 0.002), related to previous history of biliary complications (HA: P = 0.01) and HCV recurrence (HA: P = 0.004). Liver transplant recipients with everolimus monotherapy had less serum expression of TGF-β y HA than matched patients with anti-calcineurins. This difference remains when classifying patients according to donor age and time since LT. Due to the small sample size, when examining patients with a prior history of biliary complications or recurrent HCV, the difference was non-significant but trends towards the lower expression of TFG-β1 in the everolimus group. Mammalian target of rapamycin (mTOR) plays a role in the transformation of quiescent hepatocellular stellate cell to their active profibrotic state, and experimental models have demonstrated the potential activity of mTOR inhibition in attenuating fibrogenesis.

CONCLUSION: This study supports a possible role of everolimus in liver fibrosis modulation after LT in a clinical setting and suggests that tailoring immunosuppression could avoid fibrosis progression in the allograft.

Liver transplantation for hepatocellular carcinoma: how far have we come and what is the future?

SUMMARY: 

Liver transplantation is the best treatment for hepatocellular carcinoma in the setting of chronic liver disease, completely removing malignancy and underlying diseased liver tissue. Technical aspects of liver transplantation have improved over the years, along with outcomes. But challenges continue in the areas of expanding existing indications for transplant with limited organ supply, calling for optimization of patient selection and the development of alternative or adjunctive treatment options. Expansion of existing transplant criteria will help identify patients most likely to have good outcomes. Locoregional and systemic treatments showing therapeutic promise are being investigated for use in achieving acceptable oncologic effect. Improvements in post-transplant treatment and continued attempts to enlarge the donor pool will continue to provide avenues for further improvements in outcomes.

Angiosarcoma successfully treated with liver transplantation and sirolimus

Malignant liver tumors represent approximately 1% of malignancies in children. HA is a high-grade tumor of endothelial cells that is even more rare in the pediatric population. HA has a limited response to chemotherapy, radiation and resection with universal tumor recurrence with LT and nearly 100% mortality by 18 months. This is the first reported successful case of hepatic angiosarcoma in a child who was treated by LT in combination with sirolimus. Sirolimus antagonizes the mTOR pathway, which regulates cell proliferation, differentiation, and migration, and is being studied as an anti-neoplastic agent for solid tumors.

The Role of mTOR Inhibitors in Liver Transplantation: Reviewing the Evidence

Despite the success of liver transplantation, long-term complications remain, including de novo malignancies, metabolic syndrome, and the recurrence of hepatitis C virus (HCV) and hepatocellular carcinoma (HCC). The current mainstay of treatment, calcineurin inhibitors (CNIs), can also worsen posttransplant renal dysfunction, neurotoxicity, and diabetes. Clearly there is a need for better immunosuppressive agents that maintain similar rates of efficacy and renal function whilst minimizing adverse effects. The mammalian target of rapamycin (mTOR) inhibitors with a mechanism of action that is different from other immunosuppressive agents has the potential to address some of these issues. In this review we surveyed the literature for reports of the use of mTOR inhibitors in adult liver transplantation with respect to renal function, efficacy, safety, neurological symptoms, de novo tumors, and the recurrence of HCC and HCV. The results of our review indicate that mTOR inhibitors are associated with efficacy comparable to CNIs while having benefits on renal function in liver transplantation. We also consider newer dosing schedules that may limit side effects. Finally, we discuss evidence that mTOR inhibitors may have benefits in the oncology setting and in relation to HCV-related allograft fibrosis, metabolic syndrome, and neurotoxicity.

De novo sirolimus and reduced-dose tacrolimus versus standard-dose tacrolimus after liver transplantation: the 2000-2003 phase II prospective randomized trial

We studied whether the use of sirolimus with reduced-dose tacrolimus, as compared to standard-dose tacrolimus, after liver transplantation is safe, tolerated and efficacious. In an international multicenter, open-label, active-controlled randomized trial (2000-2003), adult primary liver transplant recipients (n=222) were randomly assigned immediately after transplantation to conventional-dose tacrolimus (trough: 7-15 ng/mL) or sirolimus (loading dose: 15 mg, initial dose: 5 mg titrated to a trough of 4-11 ng/mL) and reduced-dose tacrolimus (trough: 3-7 ng/mL). The study was terminated after 21 months due to imbalance in adverse events. The 24-month cumulative incidence of graft loss (26.4% vs. 12.5%, p=0.009) and patient death (20% vs. 8%, p=0.010) was higher in subjects receiving sirolimus. A numerically higher rate of hepatic artery thrombosis/portal vein thrombosis was observed in the sirolimus arm (8% vs. 3%, p=0.065). The incidence of sepsis was higher in the sirolimus arm (20.4% vs. 7.2%, p=0.006). Rates of acute cellular rejection were similar between the two groups. Early use of sirolimus using a loading dose followed by maintenance doses and reduced-dose tacrolimus in de novo liver transplant recipients is associated with higher rates of graft loss, death and sepsis when compared to the use of conventional-dose tacrolimus alone.

Immunomodulating options for liver transplant patients

Much has changed since the early years of liver transplantation. Improvements in post-transplant survival are largely due to more selective and less toxic immunosuppression regimens and advances in operative and perioperative care. This has allowed liver transplantation to become an extremely successful treatment option for patients with endstage liver disease. Beginning with cyclosporine, a cyclic endecapeptide of fungal origin and the first of the calcineurin inhibitors to find widespread use, immunosuppressive regimens have evolved to include additional calcineurin inhibitors, steroids, mTOR inhibitors, antimetabolites and antibodies, mostly targeting T-cell activation. This review will present currently available immunosuppressive agents used in the perioperative period of liver transplantation, as well as maintenance treatments, tailoring therapeutic strategies for specific populations, and advances in immune monitoring and tolerance.

Transplantation for hepatocellular carcinoma: the North American experience

Liver transplantation for hepatocellular carcinoma (HCC) in North America has undergone substantial change since its inception. Transplantation for large tumors led to near universal tumor recurrence and despite its theoretical benefit, complete liver replacement for primary hepatic malignancy was all but abandoned outside of clinical trials. With the publication of the Milan criteria interest was renewed and results of transplant for HCC began to mirror those for non-malignant indications. The adoption of MELD-based allocation led to a substantial increase in the number of transplants for HCC as MELD priority points were given to patients who met the restrictive criteria. As results of transplantation improved, several groups have pushed the boundaries of Milan and found similar results. To further possibility of transplantation for patients with tumors outside of criteria, locoregional therapies have been utilized to downstage these tumors. As the number of patients awaiting a deceased donor allograft continues to increase while the number of available deceased donor organs remains relatively constant, the roles of living donor transplantation, adjuvant, and neoadjuvant therapy will continue to evolve.

Sirolimus conversion in liver transplant recipients with calcineurin inhibitor-induced complications: efficacy and safety

OBJECTIVES

To evaluate the efficacy and safety of conversion from calcineurin inhibitors to sirolimus among liver transplant recipients with calcineurin inhibitor-induced complications.

MATERIALS AND METHODS

After receiving liver transplants, 25 patients with calcineurin inhibitor-induced complications (22 renal dysfunction and 3 new-onset diabetes mellitus) were converted from sirolimus to tacrolimus. The serum creatinine, sirolimus trough level, liver function, acute rejection episodes, and drug-related adverse effects were monitored.

RESULTS

The patients were followed for 12 to 50 months (median, 25 months). The renal function of the 22 patients with renal dysfunction improved after sirolimus conversion. The serum creatinine levels were significantly lower at 3 months after conversion versus before conversion (113.2 ± 21.8 μmol/L vs 163.2 ± 45.3 μmol/L; P < .05). At the end of the follow-up, the average serum creatinine level was 101.9 ± 23.4 μmol/L among the 20 living recipients. Diabetes also was under control in 3 diabetic recipients after the conversion. Four patients experienced episodes of acute rejection, and intravenous steroid bolus therapy was administered in 2 of them. No graft was lost because of acute rejection. The adverse effects of sirolimus included hyperlipidemia (7/25), anemia (8/25), and mouth ulcers (9/25). All these adverse effects were relieved after a short-term symptomatic therapy, and no patient was withdrawn from the conversion trial.

CONCLUSIONS

Sirolimus monotherapy is effective and safe in liver transplant recipients. Conversion to sirolimus was associated with a sustained improvement in renal function and diabetes mellitus without an increased incidence of acute rejection episodes.

Novel synergistic antitumor effects of rapamycin with bortezomib on hepatocellular carcinoma cells and orthotopic tumor model

Background

Despite recent advances in the treatment of hepatocellular carcinoma (HCC), the chemotherapy efficacy against HCC is still unsatisfactory. The mammalian target of rapamycin (mTOR) has been emerged as an important cancer therapeutic target. However, HCC cells often resistant to rapamycin because of the paradoxical activation of Akt by rapamycin. In this study, we investigated whether bortezomib could enhance the antitumor effects of rapamycin.

Methods

The effects of rapamycin and bortezomib on HCC proliferation, apoptosis, migration, and invasiveness in vitro were assessed by CCK-8 analysis, flow cytometry, Hoechst 33342 staining and transwell assays, respectively. Total and phosphorylated protein levels of Akt were detected by Western blotting. The effects of rapamycin and/or bortezomib on the mRNA expression levels of p53, p27, p21 and Bcl-2 family in HCCLM3 cells were evaluated by RT-PCR. The roles of rapamycin and bortezomib on HCC growth and metastasis in xenograft models were evaluated by tumor volumes and fluorescent signals. The effects of rapamycin and bortezomib on cell proliferation and apoptosis in vivo were test by PCNA and TUNEL staining.

Results

Bortezomib synergized with rapamycin to reduce cell growth, induce apoptosis, and inhibit cell mobility in vitro. Further mechanistic studies showed that bortezomib inhibited rapamycin-induced phosphorylated Akt, which in turn enhanced apoptosis of HCC cell lines. The alteration of the mRNA expression of cell cycle inhibitors p53, p27, p21 and apoptosis associated genes Bcl-2, Bax were also involved in the synergistic antitumor effects of rapamycin and bortezomib. P53 inhibitor PFT-α significantly attenuate the effect of rapamycin and bortezomib on cell apoptosis, which indicated that the pro-apoptotic effect of rapamycin and bortezomib may be p53-dependent. Treatment of HCCLM3-R bearing nude mice with rapamycin and bortezomib significantly enhanced tumor growth inhibition (72.4%), comparing with either rapamycin- (54.7%) or bortezomib-treated mice (22.4%). In addition, the lung metastasis was significantly suppressed in mice received the combination treatment (16.6%). The combination treatment of rapamycin and bortezomib significantly inhibited tumor cell proliferation and tumor angiogenesis in vivo.

Conclusion

The combination of rapamycin with bortezomib could be a novel and promising therapeutic approach to the treatment of HCC.

Optimization of the use of Calcineurin inhibitors in liver transplantation

Calcineurin inhibitors (CNIs), such as cyclosporin A and tacrolimus, are the cornerstone of maintenance immunosuppressive regimens in liver transplantation. CNIs prevent rejection by inhibition of calcineurin, via which lymphocyte proliferation and interleukin (IL)-2 production is prevented. Tacrolimus is now the first-choice immunosuppressant after liver transplantation, since it is associated with fewer episodes of rejection than cyclosporin A. In this review we will discuss interindividual differences, which influence tacrolimus metabolism. Because of these factors and the narrow therapeutic index of tacrolimus, monitoring of drug trough levels is necessary. Furthermore, we will discuss studies concerning conversion from the tacrolimus twice daily to tacrolimus once daily formulation in stable LT patients. Due to adverse effects of CNIs, such as chronic renal failure, hypertension, de novo malignancy and new-onset diabetes mellitus, CNI minimization strategies have been developed, which will be discussed too.

Sirolimus as renal and immunological rescue agent in pediatric liver transplant recipients

CNI have improved the outcome of LT. However, their inherent potential to nephrotoxic and sometimes-inadequate immunosuppressive effect has lead to the usage of newer drugs like SRL. Aim of this study was to review children who received SRL. Thirty-seven (20 women) children post-LT, median age 10.4 yr (0.8-17.4) with a minimum follow-up of six months comprised the study group. Indications for SRL were biopsy-proven resistant acute allograft rejection (n = 12), early CR (n = 12), and CNI-induced nephropathy with MMF intolerance (n = 11). In two patients, the indication was the recurrence of BSEP disease in the allograft. In patients with acute rejection, AST normalized in 10/12 patients. In patients with CR, AST normalized in 6/12 patients. Those with renal impairment showed improvement in their creatinine levels from a mean baseline of 99-56.7 μm (p = 0.03) and their mean cystatin C was 1.02 after SRL. Side effects leading to discontinuation of SRL were seen in three patients. SRL was effective in rescuing patients with acute and chronic allograft rejection and improving renal function in CNI-induced nephropathy group.

Potent antifibrotic activity of mTOR inhibitors sirolimus and everolimus but not of cyclosporine A and tacrolimus in experimental liver fibrosis

BACKGROUND & AIMS

Recurrence of chronic hepatitis C and progressive fibrosis in liver transplants is frequent and impairs both graft and patient survival. Whether or not the choice of immunosuppression affects progression of fibrosis remains unclear. The aim of the present study was to compare the potential of the commonly used immunosuppressants to halt experimental liver fibrosis progression.

METHODS

To induce liver fibrosis, rats underwent bile duct ligation and treatment with sirolimus (2mg/kg), everolimus (3mg/kg), tacrolimus (1mg/kg), and cyclosporin A (10mg/kg) daily for 5 weeks. Fibrosis, inflammation, and portal pressure were evaluated by histology, hydroxyproline levels, morphometry, hemodynamics, and hepatic gene expression.

RESULTS

Sirolimus and everolimus decreased fibrosis up to 70%, improved portal pressure, reduced ascites, and showed potent down-regulation of pro-fibrogenic genes, paralleled by a strong increase in matrix degradation (collagenase) activity; in contrast, tacrolimus and cyclosporine A had no or even aggravating effects on liver fibrosis in rats.

CONCLUSIONS

mTOR inhibition by sirolimus and everolimus in experimental liver fibrosis associates with significantly less fibrosis progression and portal hypertension than treatment with calcineurin inhibitors tacrolimus and cyclosporine A. These data suggest that the selection of the immunosuppressant could impact the recurrence of fibrosis in liver allografts.

Indications and effectiveness of the mammalian target of rapamycin in liver transplantation

BACKGROUND

The mammalian target of rapamycin (mTOR) inhibitors are new immunosuppressive drugs for organ transplantation. They are interesting for liver transplantation because of their absence of nephrotoxicity and potential antitumor effects, because calcineurin inhibitors (CNI) are associated with renal dysfunction post-CNI and tumors. We sought to analyze the indications, safety, and efficacy of mTOR among liver transplant patients at our center.

METHODS

We retrospectively identified patients who were treated with mTOR for their indications for liver transplantation, type of immunosuppressive therapy, acute rejection episodes, and evolution of kidney function.

RESULTS

We identified 43 (19.02%) patients treated with mTOR including 35 (81.4%) males and 8 (18.6%) females of overall average age of 56.7 (range, 44-68). In 30% of patients, the drug was introduced for kidney failure, and in 23% for actual or a high risk of hepatocellular carcinoma (HCC) recurrence. The average time to introduction of the mTOR was 6.4 months (range, 1-46). The final immunosuppressive regimen was mTOR alone (73%), or mTOR plus CNI (23%), or mTOR plus mycophenolate mofetil (4%). The average values of creatinine and urea were lower after conversion to mTOR (P < .05) with a 6.9% incidence of acute rejection episodes.

CONCLUSION

The mTOR immunosuppressive drugs are safe for liver transplant patients, effectively controlling renal dysfunction. They can be used in other indications, such as neurotoxicity, de novo tumors, and high risk of HCC recurrence. More studies are needed to clarify their long-term effectiveness.

Evolving concepts in the selection of immunosuppression regimen for liver transplant recipients

The introduction of calcineurin inhibitor (CNI) based immunosuppression has revolutionized the field of liver transplantation by dramatically reducing the incidence of acute cellular rejection and prolonging patient and allograft survival. However, the introduction of CNIs has also come at the price of increased patient morbidity, particularly with regard to the well-known nephrotoxic effects of the medications. In an effort to minimize the adverse effects, immunosuppression regimen have evolved to include the use of various induction agents and purine synthesis inhibitors to limit the dose of CNI necessary to achieve low acute cellular rejection rates. Careful assessments of risks and benefits are needed as these newer agents have their own side effect profiles. In addition, the impact of newer immunosuppression regimen on hepatitis C (HCV) recurrence has not been completely elucidated. This review will provide an overview of the most common immunosuppression regimen used in liver transplantation and discuss their impact on acute cellular rejection, patient and allograft survival, and HCV recurrence.

Switching to sirolimus-based immune suppression after liver transplantation is safe and effective: a single-center experience

BACKGROUND

Sirolimus is unlicensed for use in liver transplantation because of concerns over safety, particularly in regard to hepatic artery thrombosis and excess mortality. However, sirolimus offers potential advantages over calcineurin inhibitor-based immunosuppression, relating to its renal sparing and antiproliferative properties.

METHODS

A review was undertaken of 148 liver transplant patients converted to sirolimus over 10 years at a single center.

RESULTS

The main indications for sirolimus were renal impairment and hepatitis C virus fibrosis. One hundred eleven (75%) patients remained on sirolimus after median follow-up of 1006 days. Mean (+/-standard deviation) glomerular filtration rate improved significantly from 59+/-29 mL/min preconversion to 72+/-39 mL/min at censor point (P<0.05). Improvement in glomerular filtration rate was most marked in patients converted for renal impairment. Liver function tests remained stable or improved, particularly in patients transplanted for hepatitis C virus. Side effects attributed to sirolimus occurred in 101 (68%) patients requiring withdrawal in 20 patients (14%). Moderate increases in serum lipids were observed and controlled effectively with statins. The incidence of proteinuria increased postconversion but had no deleterious impact on renal function. No episodes of hepatic artery thrombosis were observed.

CONCLUSIONS

Sirolimus was safe and may improve outcome in selected patients after liver transplantation.

A Decade of Experience Using mTor Inhibitors in Liver Transplantation

Some studies suggest that Sirolimus (SRL) is associated with an increased risk of death in liver transplant recipients compared to treatment with calcineurin inhibitors (CNIs). We compared patients who received SRL or CNI in the first year after liver transplant. Our database included 688 patients who received a liver transplant. The patients were divided into groups. (1) CNI + MPS (mycophenolate sodium) at time of discharge. (2) CNI + MPS at time of discharge; SRL was added within the first 6 months and continued through the first year. (3) CNI + MPS at time of discharge; SRL was added within the first 6 months and discontinued before the first year. (4) SRL as primary immunosuppression. (5) SRL as primary immunosuppression and discontinued before the first year. We used mortality and graft loss as the primary measures of outcome. We also quantified renal function using the change in glomerular filtration rate (GFR), the presence of biopsy proven acute cellular reject (ACR), and steroid-resistant rejection (SRR). There were no significant differences in mortality or graft loss. There was no difference in patient or graft survival. Patients that received SRL as primary immunosuppression had 50% less rejection compared to controls.

Sirolimus in liver transplant recipients: a large single-center experience

Sirolimus (SRL) is a newer immunosuppressant whose possible benefits and side effects in comparison to calcineurin inhibitors (CNIs) still have to be addressed in the liver transplantation setting. We report the results of the use of SRL in 86 liver transplant recipients, 38 of whom received SRL as the main immunosuppressant in a CNI-sparing regimen. Indications for the use of SRL were: impaired renal function (n = 32), CNI neurotoxicity (n = 16), hepatocellular carcinoma (HCC) at high risk of recurrence (n = 21), recurrence of HCC (n = 6), de novo malignancies (n = 4), cholangiocarcinoma (n = 1), and the need to reinforce immunosuppression (n = 6). Among patients on SRL-based treatment, four episodes of acute rejection were observed, three of which occurred during the first postoperative month. Renal function significantly improved when sirolimus was introduced within the third postoperative month, while no change was observed when it was introduced later. Neurological symptoms resolved completely in 14/16 patients. The 3-year recurrence-free survival of patients with HCC on SRL was 84%. Sixty-two patients developed side effects that required drug withdrawal in seven cases. There was a reduced prevalence of hypertension and new-onset diabetes among patients under SRL. In conclusion, SRL was an effective immunosuppressant even when used in a CNI-sparing regimen. It was beneficial for patients with recently developed renal dysfunction or neurological disorders.

The impact of sirolimus on hepatocyte proliferation after living donor liver transplantation

BACKGROUND

There is a lack of data on the use of sirolimus after partial liver transplantation, especially regarding its impact on post-transplant regeneration.

METHODS

We reviewed adult living donor transplantations, with de novo sirolimus (n = 7) and without sirolimus (n = 21). Liver biopsies were stained for KI-67, a proliferation marker. Controls included specimens with normal liver parenchyma (n = 13).

RESULTS

Both groups had similar demographics, graft and patient survival and complication rates. During the first six wk and over the whole first year post-transplant, the use of sirolimus was associated with lower levels of hepatocyte proliferation compared to sirolimus-free patients, (overall, 0.3 [0-7.2] vs. 3 [0-49] KI-67 positive hepatocytes per high power field, p ≤ 0.05). The levels observed in the sirolimus group were similar to those seen in non-transplanted control patients with normal parenchyma (0.2 [0-1.3], p = NS). Post-transplant hepatocyte proliferation correlated with the serum levels of sirolimus (p ≤ 0.05), but not with those of tacrolimus or with the dose of mycophenolate mofetil (p = 0.9 and 0.3, respectively).

CONCLUSIONS

These data suggest that sirolimus is associated with decreased post-transplant hepatocyte proliferation. The clinical significance of this observation remains to be fully determined.

Sirolimus-based immunosuppression is associated with increased survival after liver transplantation for hepatocellular carcinoma

Liver transplantation is an important treatment option for selected patients with nonresectable hepatocellular carcinoma (HCC). Several reports have suggested a lower risk of posttransplant tumor recurrence with the use of sirolimus and a higher one with calcineurin inhibitors, but the selection of an ideal immunosuppression protocol is still a matter of debate. The aim of this study was to define the immunosuppression associated with the best survival after liver transplantation for HCC. It was based on the Scientific Registry of Transplant Recipients and included 2,491 adult recipients of isolated liver transplantation for HCC and 12,167 for non-HCC diagnoses between March 2002 and March 2009. All patients remained on stable maintenance immunosuppression protocols for at least 6 months posttransplant. In a multivariate analysis, only anti-CD25 antibody induction and sirolimus-based maintenance therapy were associated with improved survivals after transplantation for HCC (hazard ratio [HR] 0.64, 95% confidence interval [CI]: 0.45-0.9, P < or = 0.01; HR 0.53, 95% CI: 0.31-0.92, P < or = 0.05, respectively). The other studied drugs, including calcineurin inhibitors, did not demonstrate a significant impact. In an effort to understand whether the observed effects were due to a direct impact of the drug on tumor or more on liver transplant in general, we conducted a similar analysis on non-HCC patients. Although anti-CD25 induction was again associated with a trend toward improved survival, sirolimus showed a trend toward lower rates of survival in non-HCC recipients, confirming the specificity of its beneficial impact to cancer patients.

CONCLUSION

According to these data, sirolimus-based immunosuppression has unique posttransplant effects on HCC patients that lead to improved survival.

Everolimus de novo in liver transplantation

The safety and tolerability of everolimus has been evaluated in a randomized, phase II trial, comparing 3 doses of everolimus to a placebo, in association with cyclosporine and corticosteroids, after liver transplantation. There were no significant differences between groups in the rates of the composite end point (graft failure, biopsy-proven acute rejection, graft loss, death, or loss to follow-up) or its individual components. Although there were lower rates of treated acute rejection and mortality with the higher dosages (2 and 4 mg/day), these did not reach statistical significance. Interestingly, freedom from rejection correlated with trough blood levels of everolimus: patients with levels of 3 ng/mL or less had rejection rates 3-fold higher than patients with levels exceeding 3 ng/mL. All graft losses and most deaths were associated with typical posttransplant complications, not with study medication and not due to hepatic artery thrombosis. There were no clear dose-related differences among groups for hematology parameters. After transplantation, renal function declined to a similar extent in all 4 groups. The overall incidence of infection was comparable between groups (61-77%). Although the interpretation of the results of this trial is hampered by the small sample sizes of patient groups (about 30 in each group) and the high dropout rates (about 50%), this study suggests that everolimus is an effective immunosuppressive agent with an acceptable patient tolerance and safety profile after liver transplantation.

Multicentric outcome analysis of sirolimus-based immunosuppression in 252 liver transplant recipients

SUMMARY

The use of sirolimus (SRL) in orthotopic liver transplantation (OLT) has been controversial after experimental data suggested an increased risk of hepatic artery thrombosis (HAT). To assess the safety and efficacy of SRL as de novo immunosuppression in OLT recipients. Outcomes of 252 OLT patients who received SRL were compared with outcomes of 291 OLT recipients who received calcineurin inhibitor in a retrospective study. Primary outcomes of this study were: patient- and graft survivals, vascular, biliary, wound complications and rejection rates. Secondary outcomes were: postoperative infection rate, bone marrow and renal function and changes of lipid levels. Patient- and graft survivals, rejection and infection rates were similar. In the SRL group, HAT occurred in 1.2%, biliary complications in 19.4%, and incisional hernias in 9.1%. In the control group the incidence of HAT was 5.8% (P = 0.004), biliary complications 18.5% (P = NS) and incisional hernias 7.2% (P = NS). Patients on SRL experienced significantly higher levels of serum triglycerides but fewer acute cellular rejections. Bone marrow and renal functions were similar in both the groups. Our findings would suggest that SRL is safe and effective for very selected OLT recipients. Randomized controlled trials are necessary to confirm our results.

Overview of immunosuppression in liver transplantation

Continued advances in surgical techniques and immunosuppressive therapy have allowed liver transplantation to become an extremely successful treatment option for patients with end-stage liver disease. Beginning with the revolutionary discovery of cyclosporine in the 1970s, immunosuppressive regimens have evolved greatly and current statistics confirm one-year graft survival rates in excess of 80%. Immunosuppressive regimens include calcineurin inhibitors, anti-metabolites, mTOR inhibitors, steroids and antibody-based therapies. These agents target different sites in the T cell activation cascade, usually by inhibiting T cell activation or via T cell depletion. They are used as induction therapy in the immediate peri- and post-operative period, as long-term maintenance medications to preserve graft function and as salvage therapy for acute rejection in liver transplant recipients. This review will focus on existing immunosuppressive agents for liver transplantation and consider newer medications on the horizon.

A comprehensive review of immunosuppression used for liver transplantation

Since liver transplantation was approved for the treatment of end stage liver disease, calcineurin inhibitors (CNI's) have played a critical role in the preservation of allograft function. Unfortunately, these medications cause a variety of Side effects such as diabetes, hypertension and nephrotoxicity which in turn result in significant morbidity and reduced quality of life. A variety of newer immunosuppressants have been evaluated over the last decade in an attempt to either substitute for CNI's or use with reduced dose CNI's while still preserving allograft function However, current data does not recommend complete cessation of CNI's due to unacceptably high rates of allograft rejection. As these medications have their own unique adverse effects, a careful assessment on their risks and benefits is essential, particularly when additive or synergistic effects with CNI's may occur. Furthermore, the impact of these newer medications on the risk of hepatitis C recurrence and progression remains to be elucidated. Controlled trials are urgently required to assist transplant physicians with choosing the optimum immunosuppressive regimen for their patients. This review will discuss commonly used immunosuppressants prescribed in liver transplantation, emerging therapties and where appropriate, the impact of these medications on the recurrence of hepatitis C after liver transplantation.

Natural history and therapeutic management of recurrent hepatocellular carcinoma after liver transplantation

While the natural history and appropriate diagnostic and management practices are relatively well defined for hepatocellular carcinoma (HCC), data are scarce concerning the characteristic features and treatment modalities for recurrent HCC after liver transplantation. The time of recurrence appears to impact survival more significantly than localization, but to date, guidelines for therapeutic management of recurrent HCC have not been established. Data in the literature shows that late and unifocal recurrence has a better prognosis when treated by surgery or radiofrequency. In the event of early recurrence, surgery cannot be recommended due to the lack of evidence and the high risk of advanced disease. Systemic therapy can be discussed in a situation of multifocal recurrence. Proliferative signal inhibitors exhibit both immunosuppressive and antiproliferative properties and liver transplantation teams tend to introduce such treatment despite the lack of extensive data.

Pediatric liver transplantation

In previous decades, pediatric liver transplantation has become a state-of-the-art operation with excellent success and limited mortality. Graft and patient survival have continued to improve as a result of improvements in medical, surgical and anesthetic management, organ availability, immunosuppression, and identification and treatment of postoperative complications. The utilization of split-liver grafts and living-related donors has provided more organs for pediatric patients. Newer immunosuppression regimens, including induction therapy, have had a significant impact on graft and patient survival. Future developments of pediatric liver transplantation will deal with long-term follow-up, with prevention of immunosuppression-related complications and promotion of as normal growth as possible. This review describes the state-of-the-art in pediatric liver transplantation.