A comparison of tacrolimus and cyclosporine in liver transplantation: effects on renal function and cardiovascular risk status

Diabetes mellitus after kidney transplantation: role of the impaired fasting glucose in the outcome of kidney transplantation

INTRODUCTION

Most patients suffering from chronic renal insufficiency show impaired carbohydrate metabolism. Our goals were to analyze the accumulated incidence of impaired fasting glucose (IFG) and post-transplant diabetes mellitus (PTDM) after kidney transplantation in our hospital, to assess their impacts on the survival of the graft and of the patient, and to discover the major risk factors for the development of PTDM.

MATERIALS AND METHODS

We examined alterations in carbohydrate metabolism in 920 adult patients after they received kidney transplantation. Patients were followed for a minimum period of 5 yr.

RESULTS

One year after transplantation, 12.8% of the patients had developed PTDM, and 10.3% showed an IFG level. The IFG had a negative and statistically significant influence on graft and patient survival. Host and donor age, weight, hepatitis C virus infection, and acute rejection were found to be significant risk factors.

DISCUSSION

Our study found a high incidence of PTDM, as described in previous studies, but with an emphasis on a greater role played by IFG, not only in its incidence, but also as a prognostic factor for the outcome of graft and patient survival. Identifying patients at risk of developing PTDM is important in offering them early and appropriate treatment.

Role of cytochrome P450 2C8 and 2J2 genotypes in calcineurin inhibitor-induced chronic kidney disease

OBJECTIVES

The calcineurin inhibitors (CNIs) cyclosporine A (CsA) and tacrolimus (Tac) help prevent allograft rejection but are associated with nephrotoxicity. Cytochrome P450 2C8 (CYP2C8) and CYP2J2 are polymorphic enzymes expressed in the kidney that metabolize arachidonic acid (AA) to epoxyeicosatrienoic acids, promoting kidney homeostasis. This study examined the association between CNI-induced nephrotoxicity in liver transplant patients and CYP2C8 and CYP2J2 polymorphisms.

METHODS

Liver transplantation patients receiving CNIs for at least 3 years were genotyped for CYP2C8*3, CYP2C8*4, CYP2C8 Haplotypes B and C, and CYP2J2*7 and evaluated for nephrotoxicity (serum creatinine > or = 1.6 mg/dl) 3-year post-transplantation. CYP2C8 proteins were also engineered in E. coli and their activity towards AA and inhibition by CNIs was investigated in vitro.

RESULTS

The risk of kidney disease post-transplantation was positively associated with CYP2C8*3 genotype. Odds ratios for all participants carrying at least one CYP2C8*3 allele were significant [odds ratio=2.38 (1.19-4.78)]. Stratification by CNI indicated a significant association between CYP2C8*3 and nephrotoxicity among patients receiving Tac but not CsA. The risk of renal dysfunction was not significantly influenced by CYP2C8*4, CYP2J2*7, or CYP2C8 haplotype B genotypes although inheritance of haplotype C seems to be protective. In vitro, the gene products of CYP2C8*3 and CYP2C8*4 were deficient in AA epoxidation, retaining 26 and 18% of wild-type activity, respectively. Circulating plasma concentrations of CsA and Tac inhibited CYP2C8 wild-type in vitro epoxidation of AA by 17 and 35%, respectively.

CONCLUSION

Inheritance of CYP2C8*3 is associated with a higher risk of developing renal toxicity in patients treated chronically with CNIs, and especially Tac, possibly by reducing formation of kidney protecting vasodilatory epoxyeicosatrienoic acids.

Orthotopic liver transplantation and what to do during follow-up: recommendations for the practitioner

Improvements in surgical technique and the introduction of several new immunosuppressive medications mean that outcome after orthotopic liver transplantation (OLT) has improved continuously over the past 15 years. Given the increasing longevity of patients after OLT, the recognition and prevention of long-term complications after transplantation have become ever more important. With respect to graft function, physicians responsible for the everyday care of patients following transplantation should be particularly aware of the risk of late and chronic rejection episodes and of recurrence of the underlying liver disease. The major challenge of post-transplant care is, however, how best to prevent and manage the long-term adverse effects caused by the immunosuppressive medications prescribed. Screening investigations for early diagnosis of malignancy, strict control of cardiovascular risk factors, preservation of renal function, and prevention of infections are, therefore, fundamental. This Review suggests guidelines for the management of OLT recipients to improve long-term survival, overall outcome and health-related quality of life.

Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum

Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards. Considered here are the emerging generation of new agents offering an opportunity for improving long-term graft survival, minimizing CNI-related adverse events and ensuring patient well-being.A holistic, multifaceted strategy may need to be considered - initial selection and optimized use and monitoring of immunosuppressant regimens, early recognition of indicators of patient and graft dysfunction, and, where applicable, early introduction of CNI-sparing regimens facilitating CNI withdrawal. The evidence reviewed here supports these approaches but remains far from definitive in paediatric solid organ transplantation. Because de novo immunosuppression uses CNI in more than 93% of patients, reduction of CNI-related adverse effects has focused on CNI sparing or withdrawal.A recurring theme where sirolimus and mycophenolate mofetil have been used for this purpose is the importance of their early introduction to limit CNI damage and provide long-term benefit: for example, long-term renal function critically reflects that at 1 year post-transplant. While mycophenolic acid shows advantages over sirolimus in preserving renal function because the latter is associated with proteinuria, sirolimus appears the more potent immunosuppressant but also impairs early wound healing. The use of CNI-free immunosuppressant regimens with depleting or non-depleting antibodies plus sirolimus and mycophenolic acid needs much wider investigation to achieve acceptable rejection rates and conserve renal function. The adverse effects of the alternative immunosuppressants, particularly the dyslipidaemia associated with sirolimus, needs to be minimized to avoid replacing one set of adverse effects (from CNIs) with another. While we can only conjecture that judicious combinations with the second generation of novel immunosuppressants currently in development will provide these solutions, a rationale of low-dose therapy with multiple immunosuppressants acting by complementary mechanisms seems to hold the promise for efficacy with minimal toxicity until the vision of tolerance achieves reality.

Potential influence of tacrolimus and steroid avoidance on early graft function in pediatric renal transplantation

With the increasing adoption of steroid-sparing immunosuppression protocols in renal transplantation, it is important to evaluate any adverse effects of steroid avoidance on graft function. Early graft function, measured by CrCl was retrospectively studied in 158 consecutive pediatric renal transplant recipients from 1996 to 2005, receiving either steroid-free or steroid-based immunosuppression. Patients receiving steroid-free immunosuppression vs. steroid-based immunosuppression had no difference change in CrCl (DeltaCrCl) in the first week post-transplantation (p = 0.12). When stratified by corticosteroid usage, patients with higher tacrolimus trough levels (> or =14 ng/mL) had slower graft function recovery in the first week post-transplantation than those with lower tacrolimus trough levels (p = 0.008) in the steroid-free group only. Despite initial slower graft function recovery in this subgroup, there was no negative impact on graft function in the steroid-free group; in fact steroid-free patients trended towards better CrCl at six months (p = 0.047) and 12 months (p < 0.001) post-transplant than the steroid-based group. With the improved immunological outcomes with steroid avoidance, close surveillance should be performed of tacrolimus levels to avoid levels >14 ng/mL. In patients with slow recovery of early graft function, short-term perioperative steroids may be considered.

Chronic kidney disease after nonrenal solid-organ transplantation

Chronic kidney disease (CKD) is a common complication after nonrenal solid-organ transplantation. The risk for CKD is influenced by many factors, some of which have a direct impact on how such patients are treated in the pre-, peri-, and posttransplantation settings. This review describes hazards for acute and chronic kidney injury, with particular emphasis on calcineurin inhibitor-mediated nephrotoxicity. Rather than a detailed description of management issues that are common to the general CKD population, highlighted are aspects that are more specific to nonrenal solid-organ transplant recipients with a focus on liver, heart, and lung recipients. Strategies to minimize nephrotoxic insults and retard progressive renal injury are discussed, as are issues that are pertinent to dialysis and transplantation. Finally, future approaches to prevent and treat CKD without compromising function of the transplanted organ are addressed.

Impact of tacrolimus and mycophenolate mofetil combination on cardiovascular risk profile after kidney transplantation

Cardiovascular risk factors after kidney transplantation are enhanced as a result of the chronic use of immunosuppressants. Tacrolimus with mycophenolate mofetil has become the most commonly used combination after kidney transplantation. Cardiovascular risk factors that are related to the use of this combined therapy have been analyzed in various clinical trials in comparison with other immunosuppressive therapies. This review summarizes the main results of these studies regarding arterial hypertension, lipid profile, posttransplantation diabetes, renal function, and even acute rejection rate. The aim is to characterize the cardiovascular risk profile of tacrolimus and mycophenolate mofetil association when compared with older and newer immunosuppressive associations.

Oral tacrolimus for steroid-dependent and steroid-resistant ulcerative colitis in children

PURPOSE

To evaluate tacrolimus in 3 situations: for the induction of remission in children with severe steroid-resistant ulcerative colitis (UC); for steroid sparing in children with steroid-dependent UC in whom treatment with other immunosuppressants fails; and for the maintenance of remission in children with steroid-dependent and steroid-resistant UC.

PATIENTS AND METHODS

We retrospectively evaluated 18 consecutive patients (13 with pancolitis) who were treated with oral tacrolimus at our institution from May 1999 to October 2005. Nine patients had steroid-resistant UC and 9 patients were steroid-dependent. We started patients initially on tacrolimus 0.2 mg/kg divided twice daily, with a goal plasma trough level of 10 to 15 ng/mL for the first 2 weeks, and then titrated doses to achieve plasma levels between 7 and 12 ng/mL after induction.

RESULTS

Of the 18 patients in this study, 17 showed a positive response to tacrolimus therapy (ie, cessation of diarrhea and other symptoms) and 5 showed a prolonged response to tacrolimus. The mean time from initiation of tacrolimus therapy until response was 8.5 days. The mean duration of response was 260 days. Eleven of 18 patients required colectomy, including all of the patients with steroid-resistant UC, but only 2 of 9 who were steroid-dependent. The mean time from initiation of tacrolimus until colectomy was 392 days.

CONCLUSIONS

It is possible that tacrolimus may benefit selected patients with steroid-dependent UC, including those who are intolerant of 6-mercaptopurine or azathioprine. Conversely, patients with steroid-resistant UC are unlikely to sustain a prolonged clinical response to tacrolimus and seem to require colectomy eventually. Careful considerations of risk versus benefit, as well as close monitoring for adverse effects, are essential in all patients.

Reducing the risks of cardiovascular disease in liver allograft recipients

Liver allograft recipients are at increased risk of death from cerebrovascular and cardiovascular disease. We propose the following strategy of risk-reduction, based on currently available literature. Lifestyle: standard advice should be given (avoidance of smoking, excess alcohol and obesity, adequate exercise, reduction of excess sodium intake). Hypertension: target blood pressure should be 140/90 mmHg or lower, but for those with diabetes or renal disease, 130/80 mmHg or lower. For patients without proteinuria, antihypertensive therapy should be initiated with a calcium channel blocker and for those with proteinuria, an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor blocker. If monotherapy fails to achieve adequate response, calcium channel blockers and ACE-inhibitors or angiotensin II receptor blockers should be combined. If hypertension remains uncontrolled, an alpha-blocker may be added. Consideration should be given to changing immunosuppression and avoiding use of calcineurin inhibitors. Diabetes: recipients should be regularly screened for diabetes. For patients with new-onset diabetes after transplant, stepwise therapy should be guided by HbA1c concentrations, as with type II diabetes mellitus. Hyperlipidemia: annual screening of lipid profile should be undertaken, with treatment thresholds and targets based on those advocated for the high risk general population. Dietary intervention is appropriate for all patients. A statin should be considered as the first line treatment to achieve specified targets. In patients receiving a calcineurin inhibitor, Pravastatin should be commenced at a dose of 10 mg/day. In patients receiving other forms of immunosuppression, pravastatin may be commenced at a dose of 20 mg/day. Liver tests should be monitored and patients warned to report myalgia. If monotherapy is inadequate, ezetimibe or a fibrate may be added. Consideration may be given to change in immunosuppression if combination lipid-lowering therapy proves inadequate.

Liver transplantation: an update 2007

PURPOSE OF REVIEW

Recent attention in liver transplantation has focused on equity in organ allocation and management of posttransplant complications.

RECENT FINDINGS

Adoption of the model for end-stage liver disease for liver allocation has been successful in implementing a system based on medical urgency rather than waiting time. Refinements are being studied in improving the prediction of mortality and improving transplant benefit by balancing pretransplant mortality and posttransplant survival. Emerging literature is examining expansion of the current criteria for transplantation of hepatocellular carcinoma and the role of neoadjuvant therapy. Chronic renal dysfunction after liver transplantation is a source of considerable morbidity. Nephron-sparing immunosuppression regimens are emerging with encouraging results. Hepatitis C virus infection is difficult to differentiate histologically from rejection, although newer markers are being developed. Antiviral and immunosuppressive strategies for reducing the severity of hepatitis C virus recurrence are discussed. Alcohol relapse is common after liver transplant in alcoholic liver disease patients and can lead to worse outcomes.

SUMMARY

Organ allocation tends to evolve under the model for end-stage liver disease with a focus on maximizing transplant benefit. Hepatitis C virus, hepatocellular carcinoma, chronic renal dysfunction and alcohol relapse are major challenges, and continued research in these areas will undoubtedly lead to better outcomes for transplant recipients.

Immunosuppression with calcineurin inhibitors with respect to the outcome of HCV recurrence after liver transplantation: results of a meta-analysis

A controversy exists over whether the outcome of a hepatitis C virus (HCV)-infection-related liver transplant differs based on the calcineurin inhibitor (CNI) used. We have performed a systematic review and a subsequent meta-analysis evaluating tacrolimus (Tac)-based vs. cyclosporine A-based immunosuppression in HCV-infected liver transplant recipients. Searches were conducted to locate randomized controlled trials comparing Tac vs. cyclosporine A. Data on HCV liver transplant recipients were obtained, independently of whether the study was specifically designed for patients with this disease or not. A fixed effects model was used for statistical pooling of the relative risks (RR) for the different outcomes. A total of 5 articles (366 patients) fulfilled the inclusion criteria. Statistically significant differences between Tac-based vs. cyclosporine A-based therapies were not found for mortality (P = 0.11; RR = 0.72; 95% confidence interval [CI], 0.49-1.08), graft survival (P = 0.37; RR = 0.86; 95% CI, 0.61-1.21), biopsy-proven acute rejection (P = 0.65; RR = 0.91; 95% CI, 0.61-1.36), corticoresistant acute rejection (P = 0.26; RR = 2.25; 95% CI, 0.55-9.29), and fibrosing cholestatic hepatitis (P = 0.92; RR = 0.96; 95% CI, 0.41-2.26). In 1 study, no differences were detected regarding severe fibrosis at 1 yr. In conclusion, patient and graft survivals in HCV-positive liver transplant patients are similar independently of the CNI selected as basic immunosuppressant. Unfortunately, data on the severity of recurrence and effect on viremia are scarce. Well-designed randomized prospective studies are needed to determine whether there are differences between the 2 CNIs regarding these specific variables.

Immunosuppression in pediatric solid organ transplantation: opportunities, risks, and management

The pediatric transplant community stands at a time of unprecedented choice of immunosuppressive agents - and with a legacy of morbidity from those agents used in the previous two decades. This review considers the clinical utility and side-effect profiles of immunosuppressants used widely in current practice (e.g., glucocorticoids, azathioprine, ciclosporin, tacrolimus, mycophenolate, and sirolimus) and those agents which are in increasing use or in evaluation (e.g., IL-2 receptor antibodies, everolimus, FTY720, LEA29Y, and deoxyspergualin). Further consideration is given to the wider drug interactions likely during the use of new immunosuppressant regimens and to our growing awareness of the influences of genetic heterogeneity on drug efficacy and handling. Finally, we consider the new demands being placed on the use of drug monitoring to regulate dosage of this new repertoire of immunosuppressants.

Drug insight: novel small molecules and drugs for immunosuppression

Gastrointestinal diseases can result from the inadequate or excessive response of the immune system to self or innocuous antigens. Moreover, the physiologic activation of the immune system against non-self antigens is a major clinical problem in liver organ transplantation. At present, many drugs are available that suppress the activation of the immune system, although most of the currently used immunosuppressive drugs lack specificity in terms of their molecular targets and, therefore, have the potential to generate numerous side effects. The advances that have been made in understanding the molecular events that underlie the activation of the immune system have led to the development of a new generation of 'small molecules' that are endowed with immunosuppressive properties and can serve as immunomodulatory agents. Among these new small molecules, inhibitors of Janus kinase 3, p21-Rac1 and p38 mitogen-activated protein kinase represent the most innovative approach to immunosuppression, and could be a promising alternative to current immunosuppressive therapies. Here, we report on the progress that has been made in the development of small molecules in the field of gastroenterology.

Chronic kidney disease post-liver transplantation

BACKGROUND

Renal disease is a recognized complication of orthotopic liver transplantation (OLT). We aimed to determine the incidence of all stages of chronic kidney disease (CKD), as defined in the Kidney Disease Outcomes Quality Initiative Guidelines. We also wanted to determine the risk factors for development of CKD and its impact on patient survival.

METHODS

All patients who underwent cadaveric OLT, from January 1993 until July 2004, were analysed. The glomerular filtration rate (GFR) was determined using the equation developed by the Modification of Diet in Renal Disease Study. Thirty potential risk factors were examined by univariate and multivariate ordinal logistic regression analysis. Kaplan-Meier survival analysis, the log-rank test and Cox regression analysis were performed to evaluate the survival data.

RESULTS

A total of 230 patients were included (107 males and 123 females) with a mean age of 47.7 years (4.5-70.35). Mean follow-up was 5.57 years (0.53-16.5). The following was the 10 year cumulative incidence for each stage of CKD: 0/1, 9.61%; 2, 53.71%; 3, 56.77%; 4, 6.11%; 5, 2.62%. Female gender, age, pre-OLT proteinuria, lower GFR from 1 year and higher creatinine from 6 months were associated with progression of CKD. The use of tacrolimus had a favourable impact. A GFR <30 ml/min, the need for re-transplantation and fulminant hepatic failure were all associated with reduced patient survival.

CONCLUSIONS

Moderate CKD was very prevalent. We identified the risk factors for progression of CKD and also that severe CKD was associated with reduced patient survival.

Liver transplantation: an update

PURPOSE OF REVIEW

Recent attention in liver transplantation has focused on equity in organ allocation and management of post-transplant complications.

RECENT FINDINGS

Adoption of the model for end-stage liver disease (MELD) for liver allocation has been successful in implementing a system based on medical urgency rather than waiting time. Refinements are being studied in reducing geographic disparities and improving transplant benefit by balancing pre-transplant mortality and post-transplant survival. With hepatocellular carcinoma becoming a bigger proportion of liver transplants since MELD, emerging literature is examining expansion of the current criteria for transplantation of hepatocellular carcinoma. Hepatitis C virus infection is associated with worse patient and graft survival post-transplantation than other liver diseases. The optimal timing and delivery of current antiviral therapy and immunosuppressive strategies in reducing the severity of hepatitis C virus recurrence post-transplantation are discussed. Chronic renal dysfunction after liver transplantation is a source of considerable morbidity. Nephron-sparing immunosuppression regimens are emerging with encouraging results.

SUMMARY

Organ allocation tends to evolve under MELD with a focus on reducing geographic disparities and maximizing transplant benefit. Hepatitis C virus, hepatocellular carcinoma and chronic renal dysfunction are a major challenge and continued research in these areas will undoubtedly lead to better outcomes for transplant recipients.

Impact of implementation of the MELD scoring system on the prevalence and incidence of chronic renal disease following liver transplantation

The implementation of the model for end-stage liver disease (MELD) score decreased mortality of those awaiting liver transplantation (LT); however, the impact of the MELD allocation system on the risk of chronic renal disease after LT remains unknown. We conducted a non-concurrent single-center cohort study of 174 patients undergoing LT at our center. We compared patients who underwent LT one year prior to MELD implementation (pre-MELD cohort) to those patients who underwent LT 1 year following MELD implementation (MELD cohort). All patients were followed for at least 2 years after LT. Stage 3 chronic renal disease (CRD-3) was defined by an estimated creatinine clearance (CL(Cr)) below 60 ml/min/1.73 m2, and stage 4 chronic renal disease (CRD-4) was defined by an estimated CL(Cr) below 30 mL/min/1.73 m2 according to the validated Modification of Diet and Renal Disease (MDRD) formula. Requirement of kidney transplantation and need for hemodialysis were also evaluated following LT. The pre-MELD cohort (n=97) and the MELD cohort (n=77) were comparable in baseline characteristics, prevalence of diabetes and hypertension, and immunosuppression. Mean calculated MELD score in the pre-MELD cohort was significantly lower than in the MELD cohort (16 vs. 19, P < 0.05). The estimated CL(Cr) at time of LT was lower in the MELD cohort compared with the pre-MELD cohort (75 vs. 95, P < 0.01). However, the incidence and prevalence of CRD-3 and CRD-4 at 6, 12, and 24 months after LT were comparable between the two cohorts. Need for kidney transplantation or hemodialysis after LT was comparable between the groups. In multivariate analysis, serum creatinine at LT was the only variable associated with the development of CRD-3 in the first 2 years after LT. In conclusion, the implementation of the MELD allocation system is not associated with increased mortality or occurrence of CRD-3 or CRD-4 in the first 2 years after LT.