Renal function after liver transplantation: calcineurin inhibitor nephrotoxicity

Current Status of Biomarkers and Molecular Diagnostic Tools for Rejection in Liver Transplantation: Light at the End of the Tunnel?

Strategies to minimize immune-suppressive medications after liver transplantation are limited by allograft rejection. Biopsy of liver is the current standard of care in diagnosing rejection. However, it adds to physical and economic burden to the patient and has diagnostic limitations. In this review, we aim to highlight the different biomarkers to predict and diagnose acute rejection. We also aim to explore recent advances in molecular diagnostics to improve the diagnostic yield of liver biopsies.

Comparison of cystatin C, creatinine, and iohexol clearance in pediatric liver transplantation-a retrospective cohort study

Impaired renal function after pediatric (LT) is a recognized problem. Accurate monitoring of (GFR) is imperative to detect declining renal function. GFR can be estimated via s-creatinine and/or p-cystatin C or measured by inulin and or/iohexol clearances. We retrospectively compared eGFRcrea and eGFRcyst, to mGFRiohex after LT. Data from 91 children with 312 concomitant measurements of s-creatinine, p-cystatin C, and iohexol clearance, obtained between 2007 and 2015, were analyzed. eGFR was calculated by using the p-cystatin C-based CAPA and CKD-EPI formulas, and the s-creatinine-based Schwartz-LYON, FAS, revised Schwartz and MDRD formulas. Also, the arithmetic means of cystatin C-based and creatinine-based equations were used. Every calculated eGFR was compared to mGFRiohex in statistical correlation, accuracy, precision, bias, and misclassifications. Among the different equations, p-cystatin C-based formulas (CAPA and CKD-EPI) as well as the s-creatinine-based Schwartz-LYON formula showed the most correct estimates regarding accuracy (84-87.5%), bias (0.19-4.0 ml/min/1.73 m² ), and misclassification rate (24.7-25%). In patients with renal function <75 ml/min/1.73 m² , cystatin C-based formulas were significantly more accurate and less biased than creatinine-based formulas. In conclusion, S-creatinine could be used in a clinical setting on a regular basis in liver transplanted pediatric patients, with reliable results, if eGFR is calculated by the Schwartz-LYON formula. When suspected renal dysfunction, cystatin C-based eGFR should be calculated, since it gives more accurate and less biased estimates than creatinine-based eGFR, and should be confirmed by mGFR (iohexol).

Efficacy and safety of basiliximab as initial immunosuppression in liver transplantation: A single center study

INTRODUCTION AND AIM

The interleukin-2 receptor antagonist; basiliximab is used to allow delayed introduction of Calcineurin inhibitors (CNI) after liver transplantation and thus delay their renal insult. However, there is only little evidence for the safety and the efficacy of this regimen. This study aimed to evaluate the effectiveness and safety of basiliximab induction in liver transplantation.

MATERIALS AND METHODS

This study included 89 patients who were classified into two groups: standard triple immunosuppression (IS) regimen of steroid, tacrolimus (TAC) and mycophenolate mofetil (MMF) (n = 47) and induction IS regimen of basiliximab, low dose steroids and MMF with delayed introduction of CNI (n = 42). All patients were followed after liver transplantation for at least six months or until death.

RESULTS

There were no significant differences in patient survival, graft dysfunction, infection rate or type, or wound healing between both groups. The acute rejection rate was equivalent in both groups. Renal dysfunction in the first six months post-transplant was less in the basiliximab group in comparison to the other group (7.1% and 19.1% respectively).

CONCLUSION

Basiliximab-induced IS protocol is a safe regimen that reduces medium-term renal dysfunction and achieves similar survival without increasing the acute rejection or infection rate in liver transplantation recipients.

Clinical Relevance of Kidney Biopsy in Patients Qualified for Liver Transplantation and After This Procedure in the Model for End-stage Liver Disease (MELD) Era: Where Are We Today?

Chronic kidney disease (CKD) has been recognized as an increasingly common complication of liver transplantation (OLTx). Post-transplant renal dysfunction contributes to long-term morbidity and mortality following OLTx and is a very important issue in the management of liver transplant recipients. Its etiology is multifactorial and can be determined by kidney biopsy, which is too rarely done in this patient group. In the clinical context of patients with liver cirrhosis, accurate and reliable evaluation of the renal injury is crucial. We performed a review of kidney biopsies in patients with symptoms of CKD (proteinuria/hematuria/elevated creatinine) before and after liver transplantation in the published literature. Kidney biopsies were performed either before or after liver transplantation using percutaneous technique. There are few reports on transjugular kidney biopsy. Biopsy results prevented unnecessary modification of immunosuppressive therapy or selection of candidates for liver transplantation. In our opinion, kidney biopsy is a clinically relevant diagnostic approach to recognize kidney disease before and after liver transplantation, it also helps with the management of kidney disease in this population, and it is safe. Kidney biopsy should be offered more often in liver transplant patients to ensure appropriate therapy in concomitant CKD in this population. Our decisions today will impact clinical outcomes in the future.

Conversion from Standard-Release Tacrolimus to MeltDose® Tacrolimus (LCPT) Improves Renal Function after Liver Transplantation

Renal impairment is a typical side effect of tacrolimus (Tac) treatment in liver transplant (LT) recipients. One strategy to avoid renal dysfunction is to increase the concentration/dose (C/D) ratio by improving drug bioavailability. LT recipients converted from standard-release Tac to MeltDose^® Tac (LCPT), a novel technological formulation, were able to reduce the required Tac dose due to higher bioavailability. Hence, we hypothesize that such a conversion increases the C/D ratio, resulting in a preservation of renal function. In the intervention group, patients were switched from standard-release Tac to LCPT. Clinical data were collected for 12 months after conversion. Patients maintained on standard-release Tac were enrolled as a control group. Twelve months after conversion to LCPT, median C/D ratio had increased significantly by 50% (p < 0.001), with the first significant increase seen 3 months after conversion (p = 0.008). In contrast, C/D ratio in the control group was unchanged after 12 months (1.75 vs. 1.76; p = 0.847). Estimated glomerular filtration rate (eGFR) had already significantly deteriorated in the control group at 9 months (65.6 vs. 70.6 mL/min/1.73 m² at study onset; p = 0.006). Notably, patients converted to LCPT already had significant recovery of mean eGFR 6 months after conversion (67.5 vs. 65.3 mL/min/1.73 m² at study onset; p = 0.029). In summary, conversion of LT recipients to LCPT increased C/D ratio associated with renal function improvement.

Key role of renal biopsy in management of progressive chronic kidney disease in liver graft recipients

AIMS

Chronic kidney disease (CKD) is a common complication after liver transplantation (LT). The etiology of CKD is broad and may only be assessed accurately by renal histology. The current study aimed to analyze the safety of renal biopsy in daily clinical practice as well as its usefulness regarding management of CKD after LT.

METHODS

We performed a retrospective analysis of clinical data and renal biopsies obtained from patients with severe renal impairment (overt proteinuria, progressive deterioration of renal function) after LT with respect to safety, etiology of renal disease, and therapeutic consequences.

RESULTS

Renal biopsies were obtained from 14 patients at median (minimum-maximum) 3 (0.2-12) years after LT. No major complications associated with renal biopsy were observed. Histomorphological alterations were varied (nephrosclerosis, n = 5; IgA-glomerulonephritis, n = 4; tenofovir-associated nephropathy, membranoproliferative glomerulonephritis type 1, membranous glomerulonephritis, amyloid A amyloidosis, and calcineurin inhibitor nephropathy, n = 1, respectively). The diagnosis of specific renal diseases other than calcineurin-inhibitor nephrotoxicity facilitated specific treaments and avoided unnecessary modification of immunosuppression in the majority of patients.

CONCLUSIONS

Renal biopsy in patients with CKD after LT seems safe and may offer specific therapeutic options. Furthermore, unnecessary changes of immunosuppression can be avoided in a considerable number of patients.

Impaired Renal Function Should Not Be a Barrier to Transplantation in Patients With Cystic Fibrosis

BACKGROUND

Previous studies have demonstrated an association between pretransplantation renal dysfunction (PRD) and increased mortality after lung transplantation (LT). The purpose of this study was to determine whether PRD impacts survival after LT in patients with cystic fibrosis (CF).

METHODS

We queried the United Network for Organ Sharing (UNOS) database to identify all adult (≥18 years) recipients with CF who underwent isolated LT from May 4, 2005 to December 31, 2014. We separated recipients into those with and those without PRD (glomerular filtration rate [GFR] ≤60 mL/min). We excluded patients who required dialysis before transplantation. Kaplan-Meier analysis was used to assess unadjusted survival differences. Cox proportional hazards modeling was then performed across 26 variables to assess the risk-adjusted impact of PRD on 1-, 3-, and 5-year mortality.

RESULTS

Isolated LT was performed on 1,830 patients with CF; 17 patients were excluded because of pretransplantation dialysis. Eighty-two of 1,813 patients (4.5%) had PRD (GFR ≤60 mL/min). Kaplan-Meier analysis revealed no survival differences between PRD and non-PRD groups at 1 year (85.3% versus 89.5%; log-rank p = 0.23), 3 years (71.0% versus 72.5%; p = 0.57), or 5 years (63.3% versus 59.8%; p = 0.95). After risk adjustment, PRD was not independently associated with an increased hazard for mortality at 1 year (hazard ratio [HR], 1.38 [95% confidence interval [CI], 0.74-2.58]; p = 0.31), 3 years (HR, 1.44 [95% CI, 0.92-2.24]; p = 0.11), or 5 years (HR, 1.30 [95% CI, 0.86-1.94]; p = 0.29).

CONCLUSIONS

Although PRD has historically served as a relative contraindication to LT, our study is the first to suggest that among CF recipients, PRD was not associated with increased hazard for mortality out to 5 years after LT.

Interaction of pre-transplant recipient characteristics and renal function in lung transplant survival

BACKGROUND

There has been little investigation into the potential interaction of recipient characteristics with the association of pre-transplant renal functions and survival after lung transplantation. In this study we tested the hypothesis that association of pre-transplant renal function and post-transplant mortality varies among recipient subgroups.

METHODS

We queried the United Network for Organ Sharing (UNOS) database for adult patients (≥18 years of age) undergoing lung transplantation between May 2005 and March 2015. The study population (n = 15,540) was split into 3 groups (90 to 150, 60 to 89.9 and 30 to 59.9 ml/min/1.73 m2) based on the estimated glomerular filtration rate (Chronic Kidney Disease Epidemiology Collaboration equation) at the time of listing. We utilized multivariable inverse probability weighted Cox proportional hazard models to compare the association of glomerular filtration rate (GFR) groups with mortality among recipient subgroups.

RESULTS

Overall, there was an independent and graded inverse association between the estimated GFR (eGFR) and mortality, with the hazard of mortality significantly rising with listing eGFR <60 ml/min/1.73 m2. The association between low eGFR and mortality was more consistent and stronger for older (>45 years), non-African-American and non-diabetic patients as well as those with low lung allocation score (LAS <40). Among the diagnosis groups, patients with vascular diseases had the strongest association between low eGFR and poor survival. Sensitivity analyses conducted using an alternate equation to estimate the GFR (Modification of Diet in Renal Disease) supported these associations.

CONCLUSIONS

Prognostic significance of pre-transplant renal functions varies significantly among recipient subgroups. It may be appropriate to develop a customized approach toward assessing and interpreting renal function to determine transplant candidacy.

Predictors of renal recovery in patients with pre-orthotopic liver transplant (OLT) renal dysfunction

BACKGROUND

Renal dysfunction occurs commonly in patients awaiting orthotopic liver transplantation (OLT) for end-stage liver disease. The use of simultaneous liver-kidney transplantation has increased in the MELD scoring era. As patients may recover renal function after OLT, identifying factors predictive of renal recovery is a critical issue, especially given the scarcity of available organs.

METHODS

Employing the UNOS database, we sought to identify donor- and patient-related predictors of renal recovery among 1720 patients with pre-OLT renal dysfunction and transplanted from 1989 to 2005. Recovery of renal function post-OLT was defined as a composite endpoint of serum creatinine (SCr) ≤1.5 mg/dL at discharge and survival ≥29 days. Pre-OLT renal dysfunction was defined as any of the following: SCr ≥2 mg/dL at any time while awaiting OLT or need for renal replacement therapy (RRT) at the time of registration and/or OLT.

RESULTS

Independent predictors of recovery of renal function post-OLT were absence of hepatic allograft dysfunction, transplantation during MELD era, recipient female sex, decreased donor age, decreased recipient ALT at time of OLT, decreased recipient body mass index at registration, use of anti-thymocyte globulin as induction therapy, and longer wait time from registration. Contrary to popular belief, a requirement for RRT, even for prolonged periods in excess of 8 weeks, was not an independent predictor of failure to recover renal function post-OLT.

CONCLUSION

These data indicate that the duration of renal dysfunction, even among those requiring RRT, is a poor way to discriminate reversible from irreversible renal dysfunction.

Calcineurin inhibitors in liver transplantation - still champions or threatened by serious competitors?

Current strategies for immunosuppression in liver transplant (LT) recipients include the design of protocols targeting a more individualized approach to reduce risk factors such as renal failure, cardiovascular complications and malignancies. Renal injury in LT recipients may be often multifactorial and is associated with increased risk of post-transplant morbidity and mortality. The quest for low toxicity immunosuppressive regimens has been challenging and resulted in CNI minimization protocols or CNI withdrawal and conversion to mycophenolate mofetil (MMF) and/or mammalian target of rapamycin inhibitor-based immunosuppressive regimens. Use of antibody induction to delay CNI administration may be an option in particular in immunocompromized, critically ill patients with high MELD scores. Protocols including MMF introduction and concomitant CNI minimization have the potential to recover renal function even in the medium and long term after LT. We review on hot topics in the prevention and management of acute and chronic renal injury in LT patients. For this purpose, we present and critically discuss results from immunosuppressive studies published in the current literature or presented at recent LT meetings.

Long-term outcome of conversion to sirolimus monotherapy after liver transplant

OBJECTIVES

This study sought to assess the long-term efficacy and safety of conversion from a calcineurin inhibitor-based immunosuppressive regimen to sirolimus monotherapy in liver transplant recipients with renal dysfunction.

MATERIALS AND METHODS

Twenty-five liver transplant recipients with calcineurin inhibitor-based immunosuppression were included in this single-center, prospective study. Indications were renal dysfunction, avoidance of tumor recurrence, combination renal dysfunction and avoidance of tumor recurrence, and calcineurin inhibitor-related adverse effects.

RESULTS

Mean interval between liver transplant and initiation of sirolimus monotherapy was 51.7 months. The mean follow-up was 75.6 months. The mean ± SD sirolimus whole-blood trough level was 9.0 ± 2.8 ng/mL after 6 months and 6.0 ± 1.8 ng/mL after 18 months. No rejection episodes occurred. There was an improvement of the mean creatinine level: 156.1 ± 54.9 μmol/L before conversion versus 129.1 ± 34.7 μmol/L approximately 3 years after conversion (P < .05). The glomerular filtration rate, measured by technetium Tc-99m-diethylenetriamine penta-acetic aerosol scintigraphy, improved from 27.4 ± 6.8 mL/min/1.73 m(2) before conversion to 43.3 ± 6.3 mL/min/1.73 m(2) at final follow-up. Proteinuria increased after conversion to sirolimus after 6 months (P < .05) and at last follow-up. The systolic blood pressure decreased from 151.5 ± 20.2 to 132.1 ± 19.4 mm Hg, and the diastolic from 89.7 ± 11.2 to 82.1 ± 9.1 mm Hg at last follow-up. Serum cholesterol and serum triglyceride levels were nearly unchanged. However, 50% of the patients were treated with lipid-lowering agents. Four patients had sirolimus-induced adverse effects (thrombocytopenia, gingival hyperplasia, oral ulceration).

CONCLUSIONS

Conversion from calcineurin inhibitors to sirolimus monotherapy after liver transplant results in stabilization of renal function in 75% to 85% of cases and of blood pressure, without increased risk of rejection. The spectrum of adverse effects is low.

Secreted klotho and chronic kidney disease

Soluble Klotho (sKl) in the circulation can be generated directly by alterative splicing of the Klotho transcript or the extracellular domain of membrane Klotho can be released from membrane-anchored Klotho on the cell surface. Unlike membrane Klotho which functions as a coreceptor for fibroblast growth factor-23 (FGF23), sKl, acts as hormonal factor and plays important roles in anti-aging, anti-oxidation, modulation of ion transport, and Wnt signaling. Emerging evidence reveals that Klotho deficiency is an early biomarker for chronic kidney diseases as well as a pathogenic factor. Klotho deficiency is associated with progression and chronic complications in chronic kidney disease including vascular calcification, cardiac hypertrophy, and secondary hyperparathyroidism. In multiple experimental models, replacement of sKl, or manipulated up-regulation of endogenous Klotho protect the kidney from renal insults, preserve kidney function, and suppress renal fibrosis, in chronic kidney disease. Klotho is a highly promising candidate on the horizon as an early biomarker, and as a novel therapeutic agent for chronic kidney disease.

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.

Renal Function in Patients with Orthotopic Liver Transplantation

Due to multiple reasons, acute renal failure (ARF) commonly develops in the early postoperative period of orthotopic liver transplantation (OLT) recipients. The records of OLT recipients between 1999 and 2004 were evaluated. Age, gender, primary disease, history of diabetes, immunosuppressive drugs, pre- and postoperative renal function tests, serum electrolytes, dialysis, liver functions tests, and renal function tests in follow-up period were noted. We followed 16 patients with OLT in our center. ARF developed in 8 patients. Dialysis was performed in only 2 patients, and other patients with ARF were managed with conservative measures. Hypertensive crisis and cerebrovascular stroke developed in 1 diabetic hypertensive patient.

Improving long-term outcomes after liver transplantation in children

The objective was to review the current state of knowledge and recommend future research directions related to long-term outcomes for pediatric liver transplant recipients. A 1-day Clinical Research Workshop on Improving Long-Term Outcomes for Pediatric Liver Transplant Recipients was held on February 12, 2007, in Washington, DC. The speaker topics were germane to research priorities delineated in the chapters on Pediatric Liver Diseases and on Liver Transplantation in the Trans-NIH Action Plan for Liver Disease Research. Issues that compromise long-term well-being and survival but are amenable to existing and new research efforts were presented and discussed. Areas of research that further enhanced the research priorities in the Action Plan for Liver Disease Research included collection of longitudinal data to define emerging trends of clinical challenges; identification of risk factors associated with long-term immunosuppression complications; development of tolerance-inducing regimens; definition of biomarkers that reflect the level of clinical immunosuppression; development of instruments for the measurement of health wellness; identification of risk factors that impede growth and intellectual development before and after liver transplantation and identification of barriers and facilitators that impact nonadherence and transition of care for adolescents.

Calcineurin inhibitor-sparing regimens in solid organ transplantation: focus on improving renal function and nephrotoxicity

BACKGROUND

The calcineurin inhibitors (CNIs), cyclosporine and tacrolimus, have had a revolutionary effect on the overall success of renal transplantation through reduction in early immunologic injury and acute rejection rates. However, the CNIs have a significant adverse impact on renal function and cardiovascular disease, and extended long-term graft survival has not been achieved. The recognition of these effects sparked interest in CNI-sparing strategies. Strategies to limit CNI exposure include CNI minimization, avoidance, and withdrawal. We sought to review the impact of CNI-sparing strategies in kidney, liver, and heart transplantation.

MATERIALS AND METHODS

A PubMed search 1966 to August 2006 was conducted to identify relevant research articles, and the references of these articles as well as the authors' personal files were reviewed.

RESULTS

Calcineurin inhibitor minimization using mycophenolate mofetil or sirolimus may be associated with a modest increase in creatinine clearance (CrCl) and a decrease in serum creatinine (SCr) in the short term. Despite improvement in CrCl or SCr, CNI nephrotoxicity and chronic allograft nephrotoxicity are progressive over time when CNI exposure is maintained. In kidney transplantation, the tubulo-interstitial and glomerular damage are irreversible. Mycophenolate mofetil may improve renal outcomes during CNI minimization more than sirolimus, and antibody induction may be effective to limit CNI exposure, but longer-term follow-up data are required. Use of sirolimus with mycophenolate mofetil or azathioprine to avoid CNI exposure de novo has improved glomerular filtration rate for at least two yr in most studies in kidney transplantation; however, experience is limited in liver and heart transplantation, and reports of delayed graft function and wound healing with sirolimus may have dampened enthusiasm for de novo use. Late CNI withdrawal has achieved variable results, possibly because withdrawal was attempted after the kidney damage was too extensive. Early CNI withdrawal, prior to significant graft damage, has generally improved CrCl and markers of fibrosis and decreased chronic allograft lesions, a finding also observed with sirolimus in most CNI avoidance studies. Successful withdrawal appears to be more effective than CNI minimization.

CONCLUSIONS

Calcineurin inhibitors are associated with significant nephrotoxicity and chronic kidney damage. Minimization is associated with a modest increase in renal function, but persistent damage is observed on biopsies as long as the CNIs are continued. Avoidance is hampered by lack of experience and possible sirolimus-induced side effects. CNI withdrawal may be the best option by delivering CNIs during the early period of immunologic graft injury and then converting them to less nephrotoxic agents before significant renal damage occurs.

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.

Limited Sampling Strategy for the Estimation of Mycophenolic Acid Area Under the Plasma Concentration-Time Curve in Adult Patients Undergoing Liver Transplant

Mycophenolate mofetil (MMF), the oral prodrug of mycophenolic acid (MPA), is increasingly used in liver transplantation and plays a central role in the immunosuppressive regimen in liver transplantation. To study pharmacokinetic-pharmacodynamic relationships and therapeutic drug monitoring of MPA in the clinical setting, limited sampling strategies have been investigated for the estimation of MPA areas under the curves (AUCs). Thirty-eight adult patients undergoing liver transplant (31 males, seven females) receiving 1.0 g MMF twice daily and concomitant tacrolimus provided a total of 72 pharmacokinetic profiles. Multiple stepwise regression analysis was used to determine the algorithms for limited sampling strategies. Twenty-eight one-, two-, three-, and four-sampling estimation models were fitted (r = 0.288-0.964) to all the profiles using linear regression and were used to estimate MPA AUC0-12h comparing those estimates with the corresponding AUC0-12h values calculated with the linear trapezoidal rule, including all 10 timed MPA concentrations. The four-point estimates at C1h, C2h, C6h, and C8h resulted in the best correlation between estimated AUC and true AUC when using the formula AUC = 6.03 + 0.89C1h + 1.94C2h + 2.24C6h + 4.64 C8h (r = 0.911). Bland and Altman analysis revealed good agreement between estimated AUC and AUC from the full profile. This limited sampling strategy provides an effective approach for estimation of full MPA AUC0-12h in patients undergoing liver transplant receiving concomitant tacrolimus therapy.

Application of rapamycin in liver transplant patients with acute kidney malfunction

AIM: To explore the preventive effect of rapamycin on acute allograft rejection and kidney function recovery in liver transplant patients with acute kidney malfunction.

METHODS: A total of 25 liver transplant patients with acute kidney malfunction received rapamycin treatment as preventive measures for acute allograft rejection. Both the rejection rate and the change of kidney function were monitored.

RESULTS: Of the 25 cases, 23 survived till today with the longest time of 34 mo. The 3-mo acute rejection rate was 4%, and the kidney function of the 23 patients recovered to the normal range within 3 mo. It took more time to recover for the patients with impaired kidney function (45 ± 19 d) than that for the ones with normal kidney function (24 ± 15 d) before operation (P < 0.01).

CONCLUSION: Rapamycin can prevent the occurrence of acute allograft rejection for liver transplant patients with acute kidney malfunction, while not affect the recovery of kidney function.

Effect of Long-term Tacrolimus Immunosuppression on Renal Function in Liver Transplant Recipients

STUDY OBJECTIVES

To describe changes in renal function occurring after long-term treatment with tacrolimus in clinically stable liver transplant recipients, and to identify risk factors for a clinically significant decline in renal function in these patients.

DESIGN

Retrospective cohort study. Setting. University medical center. Patients. Four hundred thirty-two patients aged 18 years or older who underwent liver transplantation between January 1, 1996, and December 31, 2000, and received tacrolimus as part of their immunosuppressive treatment regimen.

MEASUREMENTS AND MAIN RESULTS

Six hundred patients were identified from an electronic records review. Those who received multiorgan transplants, were not receiving their first liver transplant, or died during the hospitalization were excluded from the study. Outcomes measured were change in mean glomerular filtration rate (GFR) up to 5 years after transplantation, and proportion of patients with a decline in GFR of 30% or greater from baseline to the last recorded serum creatinine level. Covariates that affected this decline were identified using a logistic regression model. Patients were followed for a mean +/- SD of 3.7 +/- 2.0 years. Mean GFR showed a statistically significant decline from baseline to end of follow-up (67.7 +/- 25.6 vs 58.4 +/- 26.5 ml/min/1.73 m(2), p<0.001). The GFR declined by 30% or more in 154 (35.6%) patients. Increasing age (odds ratio [OR] = 1.03, p=0.020), female sex (OR = 1.92, p=0.006), higher baseline GFR (OR = 1.03, p<0.001), and diagnosis of diabetes mellitus (OR = 1.74, p=0.059) were identified as predictors of this outcome.

CONCLUSION

After the acute posttransplantation period, liver transplant recipients given long-term treatment with tacrolimus experienced only small changes in GFR over time. Patients with diabetes and women had the highest risk of experiencing a clinically significant decline in renal function.

Long-term renal function after liver transplantation is related to calcineurin inhibitors blood levels

BACKGROUND

Renal dysfunction is common after liver transplantation (LT). The aim of our study was to assess the prevalence of renal dysfunction 5 yr after LT and to identify risk factors for the development of this complication.

PATIENTS AND METHODS

A total of 134 adult patients underwent LT from 1987 to 1998 and 74.6% of them were alive 5 yr after. Pre-LT, 1 and 5 yr post-LT renal function were calculated by Cockroft and modification of diet in renal disease (MDRD) formula. Since 1987 glomerular filtration rate (GFR) has been measured by radiolabeled tracers clearance (RTC). Risk factors for GFR < 50 mL/min were analyzed using a multivariate logistic regression model.

RESULTS

Mean pre-LT GFR was 79 and 85 mL/min with Cockroft and MDRD respectively; 11% of the patients had a GFR <or= 50 mL/min. 5 yr after LT, mean GFR was 63, 61 and 70 mL/min with MDRD, Cockroft and RTC respectively, GFR decreased by 26%, and 25% of the patients had a GFR < 50 mL/min. Independent risk factors associated with impaired renal function were: trough levels of cyclosporin A (CyA) >or= 150 microg/L or tacrolimus (FK) >or= 10 microg/L at 1 yr and CyA >or= 100 microg/L or FK >or= 8 microg/L at 5 yr.

CONCLUSION

5 yr after LT, patients have lost 26% of their initial GFR and 25% of them have a GFR < 50 mL/min. This complication is predicted by high levels of calcineurin inhibitors (CNI). Therefore CNI levels should be reduced as low as possible and use of alternative drugs should be considered.

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.

Posttransplantation chronic renal damage in nonrenal transplant recipients

BACKGROUND

The growing problem of relentless deterioration of renal function in patients who undergo transplantation of nonrenal solid organs is bound to have an increasingly important impact as it may not only worsen patient morbidity and mortality but also increase transplantation costs.

METHODS

We reviewed the literature in order to provide a sum of the most important data on the incidence, clinical picture, renal pathology pattern, damage mechanisms, and risk factors, along with strategies for prevention and treatment of chronic renal damage following nonrenal solid organ transplantation.

RESULTS

Literature data report that 10% to 80% of transplanted patients have some degree of renal dysfunction and that they share a common clinical picture characterized by relentless asymptomatic progression, frequent hypertension, mild urinary abnormalities, and pathology features of vascular, glomerular, tubular, and interstitial involvement. These changes are very similar to those reported for chronic nephrotoxicity from calcineurin inhibitors. The occurrence of end-stage renal disease (ESRD) requiring chronic dialysis has been reported in up to 20% of nonrenal transplant recipients. Although there are some organ-specific differences, a group of common risk factors has been recognized, including the use of calcineurin inhibitors as immunosuppressive agents, age, pretransplantation renal function, intraoperative/perioperative factors, concomitant use of other nephrotoxic drugs, infections, and posttransplantation acute renal failure.

CONCLUSION

Calcineurin inhibitor-induced nephrotoxicity is a growing problem and, as the age of recipients of nonrenal organs is increasing, this problem is destined to increase. It would therefore be advisable for nephrologists to share their experiences in immunomodulation with other specialties, so as to favor the cautious extension of calcineurin inhibitor-sparing protocols to the area of life-saving transplants.

Prevention of Renal Impairment by Continuous Infusion of Human Atrial Natriuretic Peptide after Liver Transplantation

BACKGROUND

Acute renal failure occurring immediately after liver transplantation and requiring hemodialysis is a major problem resulting in a poor prognosis. We investigated the efficacy of human atrial natriuretic peptide, which has potent natriuretic effects and unique protective effects for glomeruli in preventing acute renal failure after liver transplantation.

METHODS

Thirty-seven patients who underwent live donor liver transplantation with model for end-stage liver disease scores greater than 15 were the subjects of the study. Subjects were prospectively randomized into two groups: patients that received synthetic human atrial natriuretic peptide infusion (Group H: n=19) and those that received conventional diuretics, furosemide and potassium canrenoate (Group C: n=18). The peri- and postoperative changes in hemodynamic status and renal function were compared between the two groups.

RESULTS

There were no statistical differences in the changes in hemodynamic status between groups. Hemodialysis was required after liver transplantation in nine patients, two in Group H and seven in Group C (P=0.04). Postoperative creatinine clearance was higher in Group H (P=0.03). Aldosterone level was suppressed in group H (P=0.006).

CONCLUSIONS

Continuous infusion of synthetic human atrial natriuretic peptide might be effective for preventing acute renal failure requiring hemodialysis after liver transplantation.

The natural history of renal function following orthotopic heart transplant

BACKGROUND

The outcome of solid organ transplantation has dramatically improved after the introduction of the calcineurin inhibitor cyclosporine. With the increasing longevity of heart transplant recipients, the long-term effects of cyclosporine on renal function have become more evident. The natural history of kidney function following orthotopic heart transplant is not well defined and long-term follow up studies are scant.

METHODS

We conducted an observational study on patients who received a heart transplant at Saint Louis University Hospital between January 1, 1983 and December 31, 1988. Patients were followed up for 15 yr or until death whichever occurred first. In order to assess the effect of heart transplantation and cyclosporine exposure on long-term renal function we restricted the statistical analysis to patients who survived the first year post-transplantation.

RESULTS

A total of 68 patients received orthotopic heart transplants at Saint Louis University Hospital between 1983 and 1988. Forty-eight (71%) patients survived for more than 1 yr. All patients were treated with cyclosporine based triple immunosuppressive regimen, with gradual cyclosporine dose reduction over time. The mean duration of follow-up was 8 yr. The estimated GFR at 5 and 10 yr post-transplant were significantly lower than estimated GFR at baseline and 1 yr post-transplant. There was no significant difference between estimated GFR at 15 yr and estimated GFR at baseline or 1 yr post-transplant. The cumulative incidence of chronic renal failure (GFR < or = 29 mL/min/1.73 m2) at 5, 10 and 15 yr was 4.2, 10.4 and 12.5%, respectively (p < 0.05). The cumulative incidence of severe chronic renal failure (GFR < or = 15 mL/min/1.73 m2) at 5, 10 and 15 yr was 2.1, 8.3 and 8.3%, respectively. The mortality rate was 8, 37, and 52% at 5, 10, and 15 yr, respectively. The 10 and 15 yr survivors had an estimated GFR at 1 yr post-transplant that was significantly higher than the non-survivors. Age, pre-transplantation estimated GFR, pre-transplantation diabetes and pre-transplantation hypertension are risk factors associated with > or = 10 mL/min/1.73 m2 decrement in estimated GFR.

CONCLUSION

Heart transplant survivors beyond the first year post-transplant have a significant decrease in renal function and significant mortality observed over time. Age, pre-transplant GFR, pre-transplant diabetes and pre-transplant hypertension are important risk factors for decrement in renal function.

Simultaneous liver-kidney transplantation for glycogen storage disease type IA (von Gierke's disease)

INTRODUCTION

Glycogen storage disease type Ia (GSDIa) is due to the deficiency of glucose-6-phosphatase activity in the liver, kidney, and intestine. Although significant progress has been achieved in the management of patients with GSDIa, complications still emerge. The potential for development of liver adenomatosis and kidney failure makes these patients candidates for simultaneous liver-kidney transplantation (SLKT). Herein, we describe such a transplantation in a patient affected by this rare storage disease.

METHODS

A 25-year-old female patient with GSDIa developed hepatic adenoma and kidney failure despite dietary therapy. The patient underwent an SLKT from a cadaveric donor.

RESULTS

The operative time was 8 hours without hemotransfusion. Only a transitory lactic acidosis was observed. Laboratory results normalized on postoperative day 7. The patient was discharged on postoperative day 9. After 4 months, the patient is in good condition with well-functioning kidney and liver allografts.

CONCLUSION

Patients with end-stage renal disease secondary to GSDIa should be considered for SLKT, especially when the disease is in an early stage.

Future directions in immunosuppression

As liver transplantation is now being performed with an excellent 5-year survival rate of approximately 70% at selected centers, attention has been shifted to reduce long-term complications of calcineurin inhibitors including diabetes, hypertension, and hyperlipidemia, which have a major effect on morbidity and mortality within the transplant setting. Cyclosporine (CsA) monitoring has been performed traditionally by measurement of predose "trough" blood concentrations (C0). Recent development of 2 hour postdose CsA (C2) monitoring strategy has emerged as a much more sensitive approach for assessing the pharmacokinetics and providing greater precision in the optimization of Neoral dosing than C0 measurements. Furthermore, a reduction of risk factors for atherosclerotic vascular disease and in the incidence and severity of acute cellular rejection have been associated with the adoption of C2 monitoring. However, further data from multicenter trials are required to evaluate the long-term benefits of this new therapeutic monitoring strategy.