Role of tacrolimus in the evolution of liver transplantation

Management of Tacrolimus-Induced Toxicity With Normal Serum Levels After Liver Transplant

Drug-induced liver injury after liver transplant occurs in 1.7% of patients. Tacrolimus is an effective immunosuppressant that is used to treat acute rejection. Although rare, it can cause toxicity, which is demonstrated by cholestatic liver injury. Here, we present a case of a young male patient who was diagnosed with Wilson disease, had penicillaminechelating therapy, and underwent living related liver transplant. Within 1 month posttransplant, he developed deranged, predominantly cholestatic pattern liver function tests. Laboratory parameters showed total bilirubin of 1.12 mg/ dL, alanine aminotransferase of 553 IU/L, gammaglutamyltransferase of 624 IU/L, and tacrolimus level of 10.2 ng/mL. After thorough evaluation, a liver biopsy was performed. Liver biopsy showed hepatocellular necrosis with centrilobular cholestasis without any evidence of graft rejection. However, with normal level of tacrolimus, the biopsy was suggestive of drug-induced liver injury. Thus, tacrolimus dose was reduced, resulting in improved liver function tests and patient discharge from the hospital. Tacrolimus is an effective immunosuppressant after liver transplant and has the ability to treat early acute rejection. The patient's liver biopsy showed hepatocellular necrosis with centrilobular cholestasis without any evidence of graft rejection. Cholestatic liver injury after tacrolimus usually resolves after dose reduction or by switching to another agent. With demonstrated tacrolimus-induced toxicity in liver transplant recipients, despite normal serum levels, transplant physicians should keep high index of suspicion regarding toxicity in the posttransplant setting.

Evaluation of Humoral Response following SARS-CoV-2 mRNA-Based Vaccination in Liver Transplant Recipients Receiving Tailored Immunosuppressive Therapy

Background: The role of tailored immunosuppression (IS) in the development of the humoral response (HR) to SARS-CoV-2 mRNA-based vaccination in liver transplant (LT) recipients is unknown. Methods: This is a single-centre prospective study of patients who underwent LT between January 2015 and December 2021 and who have received three doses of mRNA-based SARS-CoV-2 vaccination. Patients undergoing Tacrolimus-based immunosuppression (TAC-IS) were compared with those undergoing Everolimus-based immunosuppression (EVR-IS). Patients receiving the TAC-EVR combination were divided into two groups based on trough TAC concentrations, i.e., above or below 5 ng/mL. HR (analysed with ECLIA) was assessed at 30 to 135 days after vaccination. The primary outcome was the presence of a positive antibody titre (≥0.8 U/mL). Secondary outcomes were the presence of a highly protective antibody titre (≥142 U/mL), median antibody titre, and incidence of COVID-19. Results: Sixty-one participants were included. Twenty-four (40%) were receiving TAC-IS and thirty-seven (60%) were receiving EVR-IS. At the median follow-up of 116 (range: 89-154) days, there were no significant differences in positive antibody titre (95.8% vs. 94.6%; p = 0.8269), highly-protective antibody titre (83.3% vs. 81.1%; p = 0.8231), median antibody titre (2410 [IQ range 350-2500] vs. 1670 [IQ range 380-2500]; p = 0.9450), and COVID-19 incidence (0% vs. 5.4%; p = 0.5148). High serum creatinine and low estimated glomerular filtration rate were risk factors for a weak or absent HR. Conclusions: Three doses of mRNA-based SARS-CoV-2 vaccination yielded a highly protective HR in LT recipients. The use of TAC or EVR-based IS does not appear to influence HR or antibody titre, while renal disease is a risk factor for a weak or null HR.

Efficacy and Safety Evaluation After Conversion From Twice-Daily to Once-Daily Tacrolimus in Stable Liver Transplant Recipients: A Phase 4, Open-Label, Single-Center Study

BACKGROUND

Simplifying immunosuppressive therapy after liver transplant may improve patient compliance, thereby preventing acute rejection and graft loss. This phase 4, open-label, single-center study was conducted to evaluate the efficacy and safety of twice-daily to once-daily tacrolimus conversion in stable liver transplant recipients.

METHODS

Between May 2017 and January 2019, twice-daily tacrolimus was converted to once-daily tacrolimus in 101 stable recipients at least 12 months post-liver transplant in Asan Medical Center. The doses of both drugs was converted to 1:1, and the target trough level was 5 to 10 ng/mL. We prospectively analyzed graft function, drug compliance, and adverse reactions after switching regimen for 24 weeks.

RESULTS

There was no acute rejection confirmed histologically within 24 weeks, which was the primary endpoint, and there was no chronic rejection, fatal deterioration of liver function, or death in any patient during this period. After conversion, the trough level of tacrolimus decreased, and the mean ± standard deviation differences between the trough level and baseline level were 1.46 (±2.41) ng/mL, 0.43 (±2.08) ng/mL, and 0.07 (±2.73) ng/mL at 3, 12, and 24 weeks after conversion, respectively. Despite transient fluctuations of the trough level, there was no evidence of rejection or graft dysfunction. There were 37 adverse reactions after conversion; most of them were mild, and thrombocytopenia developed in 1 patient as an adverse drug response. Drug compliance improved after conversion according to questionnaire responses.

CONCLUSIONS

The conversion to once-daily tacrolimus in stable liver transplant recipients is an effective and safe therapeutic strategy improving drug compliance.

Efficacy and safety of once daily tacrolimus compared to twice daily tacrolimus after liver transplantation

BACKGROUND

Once daily tacrolimus regimen was found to exhibits similar bioavailability, safety and efficacy properties compared to twice-daily tacrolimus in kidney transplantation patients.

AIM

To compare the efficacy and safety of once-daily prolonged release tacrolimus compared to twice-daily tacrolimus in liver transplantation patients.

METHODS

MEDLINE, EMBASE, CENTRAL databases were searched for clinical trials until December 2020. Efficacy outcome measured as the rate of treatment failure indicated by biopsy-proven acute rejection, Serum creatinine, graft loss, or death. Two reviewers independently selected studies, collected data and assessed risk of bias. The results are reported as risk ratio with 95% confidence interval (CI) for dichotomous data.

RESULTS

Seven studies included with 965 patients. All the included studies were of moderate quality according to the risk of bias assessment using Cochrane Risk of Bias tool. Biopsy-proven acute rejection was reported in four studies, and pooled analysis of those studies indicated similar rejections in both twice daily and once daily tacrolimus groups (risk ratio: 1.06, 95%CI: 0.84-1.34, n = 758, I² = 0%) and also we found no significant difference between both groups for renal outcome (serum creatinine; mean difference, 0.001 mg/dL, 95%CI: -0.042 to 0.043, n = 846, I² = 18.6%). Similarly, there was similar number of adverse events such as hypertension, headache, back pain, blood related disorders, infections and nausea observed in both groups.

CONCLUSION

The analysis findings confirm that both once daily and twice daily tacrolimus formulations are comparable in terms of efficacy and safety outcomes.

Perioperative Pleural Drainage in Liver Transplantation: A Retrospective Analysis from a High-Volume Liver Transplant Center

BACKGROUND Pleural effusions represent a common complication after liver transplantation (LT) and chest drain (CD) placement is frequently necessary. MATERIAL AND METHODS In this retrospective cohort study, adult LT recipients between 2009 and 2016 were analyzed for pleural effusion formation and its treatment within the first 10 postoperative days. The aim of the study was to compare different settings of CD placement with regard to intervention-related complications. RESULTS Overall, 597 patients met the inclusion criteria, of which 361 patients (60.5%) received at least 1 CD within the study period. Patients with a MELD >25 were more frequently affected (75.7% versus 56.0%, P<0.001). Typically, CDs were placed in the intensive care unit (ICU) (66.8%) or in the operating room (14.1% during LT, 11.5% in the context of reoperations). In total, 97.0% of the patients received a right-sided CD, presumably caused by local irritations. Approximately one-third (35.4%) of ICU-patients required pre-interventional optimization of coagulation. Of the 361 patients receiving a CD, 15 patients (4.2%) suffered a post-interventional hemorrhage and 6 patients (1.4%) had a pneumothorax requiring further treatment. Less complications were observed when the CD was performed in the operating room compared to the ICU: 1 out 127 patients (0.8%) versus 20 out of 332 patients (6.0%); P=0.016. CONCLUSIONS CD placement occurring in the operating room was associated with fewer complications in contrast to placement occurring in the ICU. Planned CD placement in the course of surgery might be favorable in high-risk patients.

An update on potentials and promises of T cell co-signaling molecules in transplantation

The promising outcomes of immune-checkpoint based immunotherapies in cancer have provided a proportional perspective ahead of exploiting similar approaches in allotransplantation. Belatacept (CTLA-4-Ig) is an example of costimulation blockers successfully exploited in renal transplantation. Due to the wide range of regulatory molecules characterized in the past decades, some of these molecules might be candidates as immunomodulators in the case of tolerance induction in transplantation. Although there are numerous attempts on the apprehension of the effects of co-signaling molecules on immune response, the necessity for a better understanding is evident. By increasing the knowledge on the biology of co-signaling pathways, some pitfalls are recognized and improved approaches are proposed. The blockage of CD80/CD28 axis is an instance of evolution toward more efficacy. It is now evident that anti-CD28 antibodies are more effective than CD80 blockers in animal models of transplantation. Other co-signaling axes such as PD-1/PD-L1, CD40/CD154, 2B4/CD48, and others discussed in the present review are examples of critical immunomodulatory molecules in allogeneic transplantation. We review here the outcomes of recent experiences with co-signaling molecules in preclinical studies of solid organ transplantation.

Red blood cell exchange as an approach for treating a case of severe tacrolimus overexposure

Immunosuppressive medication dosing errors are not unfrequent and may present a number of challenges to transplant clinicians. Tacrolimus (TAC) is a widely used immunosuppressant with a narrow therapeutic index and potential severe side effects, including neurotoxicity and kidney injury. We herein report a case of 60-year-old woman who underwent deceased-donor liver transplantation at our center and due to inadvertent TAC overexposure was admitted to the Intensive Care Unit because of severe neurologic impairment, kidney injury and arterial hypotension. This case was challenging because TAC is largely bound to erythrocytes, has a high molecular weight, is highly lipophilic, has a high distribution volume and cannot be removed by hemodialysis or plasmapheresis. Based on these considerations, we decided to replace TAC-saturated erythrocytes with blood-bank red cells with the aim to accelerate its clearance. The treatment was effective in decreasing TAC whole blood trough levels within the therapeutic ranges with a significant improvement of the patient's clinical status. Red-blood cell exchange is a potentially safe and effective means of managing severe and symptomatic TAC toxicity.

Evaluating twenty-years of follow-up after orthotopic liver transplantation, best practice for donor-recipient matching: What can we learn from the past era?

AIM

To characterize major determinants of 20-year survival after liver transplantation (LT).

METHODS

This longitudinal single-institution study includes 313 consecutive patients who received a LT between 1988 and 1992. Pretransplant clinical characteristics and laboratory values were assessed and compared between 20-year survivors and non-survivors. Particular attention was paid to the Model for End-Stage Liver Disease (labMELD)-score and the Eurotransplant Donor Risk Index (ET-DRI) to unravel their impact on 20-year survival after LT.

RESULTS

Twenty-year survivors were significantly younger (44 vs 50 years, P = 0.001), more likely to be female (49% vs 36%, P = 0.03) and less likely to be obese at the time of LT (19% vs 32%, P = 0.011). Mean labMELD-score (P = 0.156), rate of high-urgency LT (P = 0.210), cold-ischemia time (P = 0.994), rate of retransplantation (P = 0.12) and average donor age (28 vs 33 years, P = 0.099) were not statistically different. The mean estimated glomerular filtration rate was higher among survivors (P = 0.007). ET-DRI > 1.4 (P = 0.020) and donor age ≥ 30 years (P < 0.022) had significant influence on 20-year survival. The overall survival was not significantly impacted by labMELD-score categories (P = 0.263).

CONCLUSION

LT offers excellent long-term results in case of optimal donor and recipient conditions. However, mainly due to the current organ shortage, these ideal circumstances are rarely given; thus algorithms for donor-recipient matching need to be refined, in order to enable a maximum benefit for the recipients of high quality as well as marginal organs.

Solid state compatibility study and characterization of a novel degradation product of tacrolimus in formulation

Tacrolimus is macrolide drug that is widely used as a potent immunosuppressant. In the present work compatibility testing was conducted on physical mixtures of tacrolimus with excipients and on compatibility mixtures prepared by the simulation of manufacturing process used for the final drug product preparation. Increase in one major degradation product was detected in the presence of magnesium stearate based upon UHPLC analysis. The degradation product was isolated by preparative HPLC and its structure was elucidated by NMR and MS studies. Mechanism of the formation of this degradation product is proposed based on complementary degradation studies in a solution and structural elucidation data. The structure was proven to be alpha-hydroxy acid which is formed from the parent tacrolimus molecule through a benzilic acid type rearrangement reaction in the presence of divalent metallic cations. Degradation is facilitated at higher pH values.

Effects of converting tacrolimus formulation from twice-daily to once-daily in liver transplantation recipients

Typically, tacrolimus is administrated twice daily. Prolonged-release tacrolimus is the once-daily formulation and may be more convenient for patients. Experience with the administration of the once-daily formulation is still limited. This study enrolled 210 liver transplant recipients who had stable liver function and converted tacrolimus from a twice-daily to once-daily formulation on a 1 mg to 1 mg basis. Among 210 patients, seven patients (3.3%) were withdrawn from the once-daily formulation due to allergy and fatigue. For the other patients, the trough concentration after converting to the once-daily formulation was lower than that of the twice-daily formulation. Liver enzymes were mildly elevated in 3 months after formulation conversion and serum creatinine and uric acid were mildly decreased. Seven patients (3.4%) had clinical suspicion of acute rejection after the formulation conversion and three of them were caused by nonadherence. 155 patients (76.4%) experienced a more convenient life with an increase of social activity. Forty-seven patients (23.2%) experienced the convenience of once-daily formulation during overseas trips. In conclusion, tacrolimus can be safely converted from the twice-daily to the once-daily formulation for most stable liver recipients. Acute rejection may occur in a minority of patients during formulation conversion and should be carefully monitored.

Impact of tobacco and alcohol consumption in patients registered on waiting list on early morbidity following liver transplantation

BACKGROUND

Liver transplantation (LT) is a high-risk surgery associated with postoperative complications. Smoking and drinking are known risk factors of long-term post-LT complications, but their role in early complications is still questioned.

PATIENTS AND METHODS

We retrieved from our medical files the data of all patients registered for LT and who had had a consultation with a physician specialized in substance abuse. Consumption of alcohol, tobacco, and drugs before and after registration for LT was assessed.

RESULTS

One hundred and five patients were included. Pre-registration smoking and drinking rates were 75.3 and 69.5%, respectively. Forty-three patients continued smoking and nine continued drinking until LT. Mortality and early morbidity rates were not impacted by smoking or drinking. Active smokers had significantly increased prevalence of bacterial cholangitis in comparison to patients who stopped smoking when registered for LT.

CONCLUSION

Persistent drinking in patients registered for LT is rare as compared to smoking; however, in our series, smoking until LT was not associated with major risk of early complication, except for cholangitis. This suggests that clinicians should take time to encourage patients to quit smoking and the intervention of a team specialized in substance abuse could be highly beneficial.

Some transformations of tacrolimus, an immunosuppressive drug

Transformations of the macrocyclic lactone tacrolimus (1), an important immunosuppressive drug produced by Streptomyces species, are described. These transformation products are primarily of interest as reference substances for drug impurity analyses. Upon action of acid (p-toluenesulfonic acid in toluene), tacrolimus is dehydrated by loss of water from the β-hydroxyketone moiety with partial inversion of configuration at C-8, resulting in formation of 5-deoxy-Δ(5,6)-tacrolimus and 5-deoxy-Δ(5,6)-8-epitacrolimus. The structure of the latter was determined by single-crystal X-ray crystallography. The same products are formed upon action of free radicals (iodine in boiling toluene), along with formation of 8-epitacrolimus. The latter is converted by p-toluenesulfonic acid to 5-deoxy-Δ(5,6)-8-epitacrolimus. Treatment of tacrolimus with weak base (1,5-diazabicyclo[4.3.0]nonene) gives, in addition to 8-epitacrolimus, the open-chain acid corresponding to 5-deoxy-Δ(5,6)-tacrolimus, a rare non-cyclic derivative of tacrolimus. Strong base (t-butoxide) causes pronounced degradation of the molecule. Thermolysis of tacrolimus leads to ring expansion by an apparent [3,3]-sigmatropic rearrangement of the allylic ester moiety with subsequent loss of water from the β-hydroxyketone moiety. ¹H and ¹³C NMR spectra of the obtained compounds, complicated by the presence of amide bond rotamers and ketal moiety tautomers, were assigned by extensive use of 2D NMR techniques.

Tacrolimus (FK506) suppresses TNF-α-induced CCL2 (MCP-1) and CXCL10 (IP-10) expression via the inhibition of p38 MAP kinase activation in human colonic myofibroblasts

In order to investigate the molecular mechanisms underlying the immunosuppressive effects of tacrolimus (FK506) on intestinal inflammation, we examined whether FK506 effects cytokine/chemokine secretion in human colonic myofibroblasts. Human colonic myofibroblasts were isolated from normal human colonic tissue. The mRNA and protein expression for human CCL2 and CXCL10 were analyzed by real-time PCR and ELISA, respectively. p38 MAP kinase activation was evaluated by western blotting. Tacrolimus (1 µM) suppressed tumor necrosis factor (TNF)-α-induced CCL2 and CXCL10 mRNA expression, but did not modulate TNF-α-induced interleukin (IL)-6 or CXCL8 mRNA expression. Dose-dependent, inhibitory effects of tacrolimus on CCL2 and CXCL10 expression were observed at the mRNA and protein levels. Significant inhibitory effects of tacrolimus were observed at concentrations as low as 0.5 µM for CCL2 and 0.1 µM for CXCL10, respectively. TNF-α-induced CCL2 and CXCL10 expression depended on p38 MAP kinase activation, and tacrolimus strongly inhibited the TNF-α-induced phosphorylation of p38 MAP kinase. Tacrolimus did not affect interferon (IFN)-γ-induced signaling transducer and activator of transcription (STAT)-1 phosphorylation, nor did it modulate CXCL10 mRNA and protein expression. In conclusion, tacrolimus suppressed CCL2 and CXCL10 expression in human colonic myofibroblasts. These inhibitory effects of tacrolimus may play key roles in the therapeutic effects of colonic inflammation in inflammatory bowel disease (IBD) patients.

Systematic review: the role of tacrolimus in the management of Crohn's disease

BACKGROUND  Several published studies have evaluated the efficacy of tacrolimus in the management of Crohn's disease with variable conclusions. AIM  To review systematically the evidence examining the efficacy and safety of tacrolimus in treating Crohn's disease. METHODS  The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (PUBMED) and EMBASE (1984 to January 2011) were searched. Also, references from selected articles were examined. Case series (five or more patients), cohort and randomised controlled trials were eligible for inclusion, incorporating oral, intravenous or topical tacrolimus therapy. The primary outcome was induction of remission of active Crohn's disease. RESULTS  Eleven studies met the inclusion criteria which included 163 patients, of which 127 received tacrolimus therapy. In patients with luminal Crohn's disease, the crude pooled remission rate for tacrolimus was 44.3% (range, 7-69%) and the crude pooled response rate was 37.1% (range, 14-57%). For patients with perianal disease using systemic tacrolimus, crude pooled remission rate was 28.6% (range, 0-64%) and crude pooled response rate was 38.8% (range, 0-57%). Combining data from two studies using topical tacrolimus, 35.7% of patients achieved remission and 28.6% partial response. Nonserious adverse effects are common, particularly tremor, paraesthesia and headache. Reversible nephrotoxity occurred in 16% of patients. CONCLUSIONS  The current evidence; although of a poor quality, appears to support the use of tacrolimus in Crohn's disease. High quality randomised controlled trials are needed.

Development of osteomalacia in a post-liver transplant patient receiving adefovir dipivoxil

We report the case of a patient treated with living donor-related liver transplantation who suffered from osteomalacia during adefovir dipivoxil (ADV)-containing antiviral therapy for lamivudine-resistant hepatitis B virus infection. The patient had generalized bone pain, with severe hypophosphatemia after 20 mo of ADV therapy. Radiographic studies demonstrated the presence of osteomalacia. The peak plasma ADV level was 38 ng/mL after administration of ADV at 10 mg/d. It was also found that ADV affected the metabolism of tacrolimus, a calcineurin-inhibitor, and caused an increase in the plasma levels of tacrolimus. The disability was reversed with the withdrawal of ADV and with mineral supplementation. ADV can cause an elevation of plasma tacrolimus levels, which may be associated with renal dysfunction. High levels of ADV and tacrolimus can cause nephrotoxicity and osteomalacia. This case highlights the importance of considering a diagnosis of osteomalacia in liver transplantation recipients treated with both ADV and tacrolimus.

Initial liver graft function is a reliable predictor of tacrolimus trough levels during the first post-transplant week

The narrow therapeutic range of tacrolimus requires careful management after liver transplantation (LT). The aim of this study was to investigate the influence of graft function on tacrolimus trough levels during the first post-transplant week. Ninety-three patients receiving deceased-donor LT were observed in a prospective observational study. Graft function was determined by the new LiMAx test (maximal liver function capacity). Significant correlations between LiMAx readouts and consecutive tacrolimus levels, up to r = -0.529 (p < 0.0001), were determined throughout the observed period of time. Patients with initially poor graft function revealed higher trough levels (n = 24; 20.1 ± 11.6ng/mL) in comparison with fair (n = 40; 13.7 ± 7.8 ng/mL) and good function (n = 29; 9.5 ± 4.4ng/mL; p < 0.0001) already at the second post-transplant day. Toxic levels could be predicted with an area under receiver operating characteristic analysis AUROC=0.751 (p = 0.001) with high sensitivity and specificity. Insufficient levels could be predicted with AUROC=0.800 (p = 0.003). In conclusion, initial graft function is a major factor influencing the pharmacokinetics of tacrolimus and can be validly determined by the LiMAx test. Thus, recipients with poor functioning grafts are prone of developing toxic levels within the first week after LT, whereas patients with good functioning grafts frequently develop insufficient levels with the current immunosuppressive protocols.

The effect of tacrolimus (FK-506) on Japanese patients with refractory Crohn's disease

BACKGROUND

Recent evidence indicates that intravenous or oral therapy with tacrolimus (FK-506) is effective in treating patients with Crohn's disease. We evaluated the usefulness of tacrolimus therapy for Japanese patients with refractory Crohn's disease.

METHODS

Fourteen adult Japanese patients with Crohn's disease that was refractory to conventional therapies, including prednisolone (n = 5), azathioprine (n = 6), and infliximab (n = 5), were enrolled. Treatment with tacrolimus was started orally or intravenously and aimed for serum trough levels of 10-15 ng/ml. After the patients achieved clinical improvement, tacrolimus maintenance therapy was administered to maintain the trough level at 5-10 ng/ml.

RESULTS

All patients achieved remission or significant improvement 40 days after starting tacrolimus treatment. By 120 days after the start of therapy, 9 (64%) patients achieved remission, 2 patients (14%) achieved significant improvement, and only 3 patients (21%) relapsed. The relapsed patients were treated with infliximab therapy and achieved remission. Steroids were discontinued by the 5 patients who had taken steroids before the study began. Adverse effects of tacrolimus included a temporary increase in serum creatinine concentration (n = 1, 7%), hyperkalemia (n = 1, 7%), and tremor (n = 1, 7%).

CONCLUSIONS

Tacrolimus therapy is effective and well tolerated in patients with Crohn's disease that is refractory to conventional therapies.

Hepatotoxicity caused by both tacrolimus and cyclosporine after living donor liver transplantation

We present a case report of a posttransplant patient who had hepatotoxicity due to both tacrolimus and cyclosporine and cholestatic jaundice due to tacrolimus. The patient did not show sustained improvement in enzyme and bilirubin abnormalities after an initial change from tacrolimus to cyclosporine or with a change back to tacrolimus, but he ultimately showed improvement when the blood concentration of tacrolimus was lowered. A 56-year-old man with subacute fulminant hepatitis induced by acarbose was admitted to our hospital for living donor liver transplantation. The liver graft consisted of the left lobe from his ABO-identical son. The early posttransplant course was uneventful. The serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin improved initially, but the ALT and AST levels later increased. A liver biopsy suggested a presumptive diagnosis of drug reaction. All drugs were discontinued, the immunosuppressive agent was changed from tacrolimus to cyclosporine. After initial improvement, the ALT and AST levels increased again. Assuming a reaction to cyclosporine, we decreased the concentration of cyclosporine in the blood. The enzyme levels improved temporarily but again began to rise. We changed the immunosuppressive agent to tacrolimus, which resulted in improvements in the ALT and AST levels; however, the total bilirubin level increased. We interpreted this increase as tacrolimus-induced cholestasis; in response, we decreased the blood concentration of tacrolimus to between 3 and 5 ng/dL and added 1,000 mg of mycophenolate mofetil to the drug regimen. The patient recovered without further complications. Repeated liver biopsies throughout the hospital course suggested that the mild mononuclear cell infiltration observed in a few triads had not been caused by acute rejection but had possibly been drug-induced.

Long-term results after liver transplantation

Liver transplantation (OLT) has become a successful surgical therapy for terminal liver failure. We here report about long-term results of OLT in a single center over a period of 15 years. Between 1988 and 2002, 1365 adult OLTs were performed. Mean follow-up was 103 +/- 56 months. Main indications for OLT were viral-induced cirrhosis (27.1%), alcoholic liver disease (21%), tumors (15.7%) and cholestatic liver disease (14.6%). Retransplantation was necessary in 120 (9.6%) patients because of initial nonfunction (26.9%), recurrence of underlying disease (20.2%), acute and chronic rejection (16.8%) or thrombosis of the hepatic artery (16.8%). 275 patients (22.1%) died. Causes of death included recurrence of disease (32.1%), infections (21.8%), de novo malignancies (13.5%) and cardiovascular disease (11.6%). Patient survival after OLT was 91.4%, 82.5%, 74.7% and 68.2% after 1, 5, 10 and 15 years, and graft survival was 85.8%, 75.3%, 67.3% and 61.7% after 1, 5, 10 and 15 years, respectively. Patient survival after retransplantation was 81.6%, 68.8% and 57.1% and 48.0% after 1, 5, 10 and 15 years. This analysis reveals excellent long-term results after OLT achieved in a single center.

Effect of various immunosuppressive monotherapies on survival and histopathology of monkey islet xenografts in rats

BACKGROUND

The isolation and testing of monkey islets after transplantation in small animal models provides basic information about their functional capacity. We describe the effect of cyclosporine A (CsA), tacrolimus (FK506) or prednisolone monotherapy on preventing monkey islet graft rejection after xenoTx in a rat model. Histopathological aspects are reported.

METHODS

Indian bonnet monkey (Macaca radiata radiata) islets were isolated by a simple stationary digestion technique using collagenase. The islets were purified with dextran density gradients and were transplanted under the renal capsule of normal or diabetic rats. The rats received a daily dose of CsA, or FK506, or prednisolone, and the grafts were removed at different intervals to determine islet survival. The effect of discontinuation of CsA on islet graft survival was also monitored. Histological examination of islets transplanted into normal or streptozotocin-induced diabetic rats was carried out. In diabetic rats, islet survival was determined by the graft's ability to achieve euglycemia.

RESULTS

Reversal of diabetes was achieved in all transplanted diabetic rats, demonstrating the efficacy of the isolated monkey islets. Histological examination indicated that monkey islets survived in the presence of continuous high-dose immunosuppressive monotherapy in rats. Various types of infiltrating cells were observed in the grafted area at varying times after transplantation, depending on the immunosuppressive treatment. After discontinuation of CsA, the grafts were protected for a short period.

CONCLUSIONS

This study provided evidence for monkey islet survival after transplantation into rats receiving immunosuppressive monotherapy. Basic information on infiltrating cell types may be important in the study of xenograft rejection.

Review of the clinical experience with a modified release form of tacrolimus [FK506E (MR4)] in transplantation

Non-compliance in solid transplantation recipients is a major factor in acute graft rejection, which influences patient survival. Nowadays, tacrolimus is one of the most widely used immunosuppressant agents together with cyclosporine following kidney and liver transplantation with a standardized twice-daily dosing regimen. To improve the patients' compliance to the prescribed immunosuppressive therapy, FK506E (MR4), a modified release (MR) oral dosage form of tacrolimus has been developed for a once-daily dosing regimen. This report reviews the most recent results of clinical trials with MR tacrolimus after kidney and liver transplantation.

Late-onset acute rejection after living donor liver transplantation

AIM: To investigate the incidence and risk factors of late-onset acute rejection (LAR) and to clarify the effectiveness of our immunosuppressive regime consisting of life-long administration of tacrolimus and steroids.

METHODS: Adult living donor liver transplantation recipients (n = 204) who survived more than 6 mo after living donor liver transplantation were enrolled. Immunosuppression was achieved using tacrolimus and methylprednisolone. When adverse effects of tacrolimus were detected, the patient was switched to cyclosporine. Six months after transplantation, tacrolimus or cyclosporine was carefully maintained at a therapeutic level. The methylprednisolone dosage was maintained at 0.05 mg/kg per day by oral administration. Acute rejections that occurred more than 6 mo after the operation were defined as late-onset. The median follow-up period was 34 mo.

RESULTS: LAR was observed in 15 cases (7%) and no chronic rejection was observed. The incidence of hyperlipidemia, chronic renal failure, new-onset post-transplantation diabetes, and deep fungal infection were 13%, 2%, 24%, and 17%, respectively. Conversion from tacrolimus to cyclosporine was required in 38 patients (19%). Multivariate analysis revealed that a cyclosporine-based regimen was significantly associated with LAR.

CONCLUSION: Both LAR and drug-induced adverse events happen at a low incidence, supporting the safety and efficacy of the present immunosuppression regimen for living donor liver transplantation.

Efficacy of mycofenolate mofetil for steroid-resistant acute rejection after living donor liver transplantation

AIM: To discuss the use of mycophenolate mofetil (MMF) as an immunosuppressant in steroid resistant rejection after liver transplantation.

METHODS: The clinical records of 260 adult patients who underwent living donor liver transplantation (LDLT) were reviewed. Tacrolimus and methylprednisolone were used for primary immunosuppression. Acute rejection was first treated with steroids. When steroid resistance occurred, the patient was treated with a combination of steroids and MMF. Anti-T-cell monoclonal antibody was administered to patients who were not responsive to steroids in combination with MMF.

RESULTS: A total of 90 (35%) patients developed acute rejection. The median interval time from transplantation to the first episode was 15 d. Fifty-four patients were steroid resistant. Forty-four patients were treated with MMF and the remaining 10 required anti-T-cell monoclonal antibody treatment. Progression to chronic rejection was observed in one patient. Bone marrow suppression and gastrointestinal symptoms were the most common side effects associated with MMF use. There was no significant increase in opportunistic infections.

CONCLUSION: Our results demonstrate that MMF is a potent and safe immunosuppressive agent for rescue therapy in patients with acute rejection after LDLT.

Tacrolimus-related neurologic and renal complications in liver transplantation: A single-center experience

Among 71 patients, 19 (26.7%) experienced tacrolimus-related complications including 15 neurologic reactions and four problems with nephrotoxicity. Seven of these patients received grafts from cadaveric donors and 12 from living donors. Nine patients were children. The cohort included 5 female and 14 male subjects of mean age 26 +/- 20 (min 6, max 65) years. The common indications for the liver transplantation were cholestatic and metabolic diseases in pediatric patients, and viral hepatitis in adult patients. Blood tacrolimus levels were within the normal range. All patients with neurologic complications received antiepileptic therapy and drug conversion to rapamycin in 4 cases and to cyclosporine (CsA) in 11 cases. Six cases with Wilson disease and all cases with tyrosinemia experienced neurologic complications, which reversed in all but one case. In four cases with nephrotoxicity, we switched to rapamycin. Renal function improved in all cases. Patients with Wilson disease and tyrosinemia were more susceptible to the neurologic side effects of tacrolimus. In these cases we recommend the use of drugs with fewer neurologic side effects. Tacrolimus also has nephrotoxic effects, which can be reversed by converting to rapamycin.

No improvement in long-term liver transplant graft survival in the last decade: an analysis of the UNOS data

We analyzed change in outcomes during two successive 5-year periods (period I = 1992-1996 vs period II = 1997-2002) among 35 186 deceased adult liver transplant recipients reported to the United Network for Organ Sharing (UNOS) Registry. The 5-year graft survival was 67.4% in the first period and 67.5% in the second, though the 1-year survival had improved from 81.0 to 83.5%. Comparison of blended survival rates during the two study periods showed decreased long-term graft survival in period II, explicable by an increased number of hepatitis C virus cirrhosis (HCV) patients and an increase in patients with HCV antibodies (HCVab) during this later period. Analysis wherein these patients with HCV were excluded revealed the same long-term graft survival during both periods. Non-HCV patients who had HCVab also had worse 5-year graft survival. We conclude that hepatitis C prevented improved outcomes during period II and that improved, more effective, treatment for hepatitis C virus would have great positive impact on overall survival of liver transplant recipients.

A synergistic effect between PG490-88 and tacrolimus prolongs renal allograft survival in monkeys

This study was undertaken to determine if PG490-88 and tacrolimus (Tac) act synergistically to prevent renal allograft rejection in monkeys and to explore possible mechanisms of synergy between these agents. MHC-mismatched renal allografts were transplanted into cynomolgus monkeys after bilateral nephrectomy. Recipients were divided into the following groups: (i) no treatment; (ii) PG490-88 (0.03 mg/kg); (iii) Tac (1 mg/kg); (iv) PG490-88 (0.01 mg/kg) + Tac (1 mg/kg) and (v) PG490-88 (0.03 mg/kg) + Tac (1 mg/kg). Through synergy PG490-88 and Tac inhibited anti-CD3/PMA-induced T-cell proliferation and IFN-gamma expression in vitro. Tac monotherapy only marginally prolonged survival (27 +/- 3.2 days), while the combination of PG490-88 and Tac significantly prolonged graft survival to a median of 99 days (PG490-88 at 0.03 mg) and 38.5 days (PG490-88 at 0.01 mg/kg). Prolonged survival correlated with inhibited IgM production as well as reduced T-cell infiltration, IL-2 protein expression and NF-AT/NF-kappaB activity. We conclude that PG490-88 and a subtherapeutic dose of Tac significantly prolong renal allograft survival in monkeys through the synergistic inhibition of T-cell activation and a decrease in IFN-gamma production and NF-AT/NF-kappaB activity.

Warm ischemia-reperfusion injury is decreased by tacrolimus in steatotic rat liver

Ischemia-reperfusion (I-R) injury is poorly tolerated by fatty livers, most probably secondary to reduced cellular adenosine triphosphate (ATP) levels. We investigated the effectiveness of tacrolimus pretreatment on fatty liver I-R injury in obese Zucker rats. Tacrolimus (0.3 mg/kg, intravenously) was injected 24 hours before a 75-minute ischemic period and rats were sacrificed 6 hours later. Tacrolimus modified the response to I-R observed in obese Zucker rats, when compared to nontreated obese rats: a significant reduction in hepatocyte necrosis was associated with a significant increase in hepatocyte apoptosis. In addition, cell necrosis and apoptosis were significantly and inversely correlated in lean nontreated and treated obese Zucker rats following I-R. Tacrolimus also significantly increased the hepatic ATP levels, reduced in nontreated obese rats, toward values found in lean Zucker rat livers. This protective effect of tacrolimus was further confirmed in vivo by a significantly improved survival following pretreatment with tacrolimus, 24 hours prior to ischemia. In conclusion, in obese Zucker rat livers, tacrolimus pretreatment reversed the I-R injury toward the one found in lean Zucker rats. The correlations between ATP levels and the opposite changes in necrosis and apoptotic pathways strongly suggest a cause-effect relationship between tacrolimus and changes in ATP levels.

Optimal Initial Dose of Orally Administered Cyclosporine Following Intravenous Cyclosporine Therapy

Conversion of the main immunosuppressive agent from tacrolimus to cyclosporine (CyA) is a valuable rescue therapy for the severe adverse effects of tacrolimus. We report our experience of the conversion in living donor liver transplantation, in which tacrolimus therapy was converted to CyA. There are few reports describing the optimal initial dose of orally administered CyA (PO CyA) after intravenously administered CyA (IV CyA). We retrospectively investigated the ratio of CyA blood concentrations at 12 hours after the initiation of PO CyA to that just before the conversion, and the ratio of the initial dose of PO CyA to the total dose of IV CyA administered during the 12 hours before the conversion. Linear regression analysis revealed a close correlation between these ratios (y = 2.7 + 5.8x, r = 0.73; P = .002). We recommend that, to maintain a similar trough level of CyA during conversion in liver transplantation, Neoral should be initiated at a ninefold greater dose than the total dose of IV CyA administered during the 12 hours before conversion.

Treating hepatitis C: can you teach old dogs new tricks?

Viruses depend on host-derived factors for their efficient genome replication. Here, we demonstrate that a cellular peptidyl-prolyl cis-trans isomerase (PPIase), cyclophilin B (CyPB), is critical for the efficient replication of the hepatitis C virus genome. CyPB interacted with the HCV RNA polymerase NS5B to directly stimulate its RNA binding activity. Both the RNA interference (RNAi)-mediated reduction of endogenous CyPB expression and the induced loss of NS5B binding to CyPB decreased the levels of HCV replication. Thus, CyPB functions as a stimulatory regulator of NS5B in HCV replication machinery. This regulation mechanism for viral replication identifies CyPB as a target for antiviral therapeutic strategies.

Conversion to cyclosporine provides valuable rescue therapy for living donor adult liver transplant patients intolerant to tacrolimus: A single-center experience at the University of Tokyo

Tacrolimus-based immunosuppression is currently accepted as mainstream therapy in many transplant centers worldwide due to its potent immunosuppressive activity compared to cyclosporine. A tacrolimus-based regimen has been successfully used for our living donor liver transplantation (LDLT) recipients. Adverse effects such as neurotoxicity, nephrotoxicity, and new-onset diabetes mellitus, however, have limited its clinical application. In deceased donor liver transplantation, cyclosporine rescue therapy is valuable for such complications, but few reports have described a strategy for conversion in LDLT. Herein, we present our experience of conversion from tacrolimus to cyclosporine therapy in adult LDLT recipients. Among 203 recipients, 37 patients (18%) required conversion, primarily for neurotoxicity (41%), diabetes mellitus (16%), hematopoietic disorder (16%), and gastrointestinal intolerance (11%). Primary adverse events resolved within 2 months after conversion in 35/37 (94%) of the patients. For LDLT recipients unable to maintain effective immunosuppression with tacrolimus, conversion to cyclosporine is an effective option.

Hepatitis C infection increases the risk of new-onset diabetes after transplantation in liver allograft recipients

BACKGROUND

Recent evidence suggests that new-onset diabetes after transplant (NODAT) adversely affects orthotopic liver transplant (OLTX) patient and graft survival. The objective of this study is to evaluate the effect of hepatitis C infection on the natural history of NODAT.

METHODS

A retrospective review of 492 OLTX recipients at a single center was conducted from January 1993 to January 2003. Patients were followed for a minimum of 12 months (range 12 months-10 years). The study population consisted of 444 OLTX recipients who were either HCV positive (n = 206) or HCV negative (n = 238). NODAT was defined by the need for antidiabetic medication for at least 7 days starting anytime after OLTX. Statistical analysis was performed by using the Student t test, Kaplan-Meier survival, and chi-square tests.

RESULTS

The overall incidence of NODAT was 33% (146/444). There was a significant difference in the development of NODAT between the HCV-positive group (82/206, 40%) and the HCV-negative group (64/238, 27%) (P < .001). Other independent risk factors for development of NODAT were male gender and age >50 years.

CONCLUSION

Hepatitis C infection contributes to the development of diabetes mellitus in OLTX recipients. The mechanisms behind HCV infection and associated NODAT in HCV-positive OLTX recipients warrant further investigation.

Tacrolimus suppresses glucose-induced insulin release from pancreatic islets by reducing glucokinase activity

Tacrolimus is widely used for immunosuppressant therapy, including various organ transplantations. One of its main side effects is hyperglycemia due to reduced insulin secretion, but the mechanism remains unknown. We have investigated the metabolic effects of tacrolimus on insulin secretion at a concentration that does not influence insulin content. Twenty-four-hour exposure to 3 nM tacrolimus reduced high glucose (16.7 mM)-induced insulin secretion (control 2.14 +/- 0.08 vs. tacrolimus 1.75 +/- 0.02 ng.islet(-1).30 min(-1), P < 0.01) without affecting insulin content. In dynamic experiments, insulin secretion and NAD(P)H fluorescence during a 20-min period after 10 min of high-glucose exposure were reduced in tacrolimus-treated islets. ATP content and glucose utilization of tacrolimus-treated islets in the presence of 16.7 mM glucose were less than in control (ATP content: control 9.69 +/- 0.99 vs. tacrolimus 6.52 +/- 0.40 pmol/islet, P < 0.01; glucose utilization: control 103.8 +/- 6.9 vs. tacrolimus 74.4 +/- 5.1 pmol.islet(-1).90 min(-1), P < 0.01). However, insulin release from tacrolimus-treated islets was similar to that from control islets in the presence of 16.7 mM alpha-ketoisocaproate, a mitochondrial fuel. Glucokinase activity, which determines glycolytic velocity, was reduced by tacrolimus treatment (control 65.3 +/- 3.4 vs. tacrolimus 49.9 +/- 2.8 pmol.islet(-1).60 min(-1), P < 0.01), whereas hexokinase activity was not affected. These results indicate that glucose-stimulated insulin release is decreased by chronic exposure to tacrolimus due to reduced ATP production and glycolysis derived from reduced glucokinase activity.