The metabolic effects of cyclosporin and tacrolimus

Results of an international, randomized trial comparing glucose metabolism disorders and outcome with cyclosporine versus tacrolimus

DIRECT (Diabetes Incidence after Renal Transplantation: Neoral C(2) Monitoring Versus Tacrolimus) was a 6-month, open-label, randomized, multicenter study which used American Diabetes Association/World Health Organization criteria to define glucose abnormalities. De novo renal transplant patients were randomized to cyclosporine microemulsion (CsA-ME, using C(2) monitoring) or tacrolimus, with mycophenolic acid, steroids and basiliximab. The intent-to-treat population comprised 682 patients (336 CsA-ME, 346 tacrolimus): 567 were nondiabetic at baseline. Demographics, diabetes risk factors and steroid doses were similar between treatment groups. The primary safety endpoint, new-onset diabetes after transplant (NODAT) or impaired fasting glucose (IFG) at 6 months, occurred in 73 CsA-ME patients (26.0%) and 96 tacrolimus patients (33.6%, p = 0.046). The primary efficacy endpoint, biopsy-proven acute rejection, graft loss or death at 6 months, occurred in 43 CsA-ME patients (12.8%) and 34 tacrolimus patients (9.8%, p = 0.211). Mean glomerular filtration rate (Cockcroft-Gault) was 63.6 +/- 20.7 mL/min/1.73 m(2) in the CsA-ME cohort and 65.9 +/- 23.1 mL/min/1.73 m(2) with tacrolimus (p = 0.285); mean serum creatinine was 139 +/- 58 and 133 +/- 57 mumol/L, respectively (p = 0.005). Blood pressure was similar between treatment groups at month 6, but total cholesterol, LDL-cholesterol and triglyceride levels were significantly higher with CsA than with tacrolimus (total cholesterol:HDL remained unchanged). The profile and incidence of adverse events were similar between treatments. The incidence of NODAT or IFG at 6 months post-transplant is significantly lower with CsA-ME than with tacrolimus without a significant difference in short-term outcome.

Recurrence of nonviral diseases

As long-term graft survival and mortality after liver transplantation improve, recognition that allografts may be affected by the same disease process that resulted in the failure of the liver is of both clinical and academic importance. Recipients need to be counseled about recurrence and potential impact on graft function and graft survival; clinicians need to be aware of the potential of recurrence to interpret the clinical, laboratory, radiologic, and histologic findings and alter management. Understanding which conditions recur in the allograft and factors associated with recurrence may shed light on pathogenesis. This article discusses the recurrence of nonviral diseases after liver transplantation, diagnosis, and management.

Oral health in renal transplant recipients administered cyclosporin A or tacrolimus

OBJECTIVE

The aim of this study was to determine the oral status of renal transplant recipients receiving cyclosporin A (CsA) or tacrolimus (FK-506) as immunosuppressant.

SUBJECTS AND METHODS

A total of 88 renal transplant recipients receiving CsA (63 men and 25 women, mean age 51.4 years) and 67 receiving FK-506 (57 men and 10 women, mean age 33.5 years) were included in the study. Donor type, histocompatibility, cold ischemia time and prior delayed graft function were similar between the two groups. Demographics and pharmacological data were recorded for all subjects.

RESULTS

The results demonstrated that CsA caused a greater number of oral diseases. A greater number of gingival overgrowth was present in patients treated with CsA. However, the combined use with calcium channel blockers increased the gingival overgrowth number. The occurrence of candida in saliva was observed in 80 renal recipients treated with CsA and 20 treated with FK-506. The presence of squamous oral carcinoma (n = 3) and herpes simplex (n = 10) was observed in patients treated with CsA. These alterations were not observed in renal recipients treated with FK-506.

CONCLUSIONS

Renal recipients constitute a high-risk group for oral diseases, as they are immunocompromised. However, the FK-506 regime appears to ameliorate this effect, compared with CsA. Adequate pre- and post-transplant oral health care is recommended for these subjects, irrespective of the time interval for which the drug is administered.

Nonalcoholic fatty liver disease and liver transplantation

Nonalcoholic fatty liver disease affects a substantial proportion of the general population worldwide. This high prevalence of nonalcoholic fatty liver disease has important consequences in the donor selection process for liver transplantation, and in the posttransplant period given the high recurrence rate of disease. This paper reviews the prevalence of nonalcoholic fatty liver disease, its progressive potential, and the implications of this liver condition in both the pre- and post-liver transplantation setting.

New-onset diabetes after liver transplantation: from pathogenesis to management

New-onset diabetes mellitus (NODM) develops in approximately 15% of liver transplant recipients, and a similar proportion of patients have diabetes prior to transplantation. Preexisting diabetes and probably NODM are associated with increased mortality and risk of infection. NODM occurs more frequently among patients with hepatitis C infection; additional risk factors include family history, male gender, increasing weight, and alcoholic cirrhosis. Corticosteroid therapy, particularly bolus injections, increases likelihood of NODM, and randomized clinical trials and retrospective studies have shown NODM to occur more frequently with tacrolimus compared with cyclosporine. Patients undergoing liver transplantation should be screened for diabetes risk factors, and fasting plasma glucose should be monitored regularly in all transplant recipients. Management of NODM is essentially similar to that of diabetes in the nontransplant population, and includes dietary and lifestyle modifications. In choosing oral agents and/or insulin, the individual medical profile of the patient must be considered carefully. Corticosteroid exposure should be limited as much as possible, and reduction of calcineurin inhibitor dose is prudent. Switching from tacrolimus to cyclosporine may be required in some cases to achieve improvement or resolution. In conclusion, prospective trials are necessary to properly define antidiabetic therapy and immunosuppressive strategies in this population.

Post-Transplantation Diabetes Mellitus

Post-transplantation diabetes mellitus (PTDM) is defined as sustained hyperglycemia developing in any patient without history of diabetes before transplantation, that meets the current diagnostic criteria by the American Diabetes Association or the World Health Organization. Several risk factors have been identified: age, nonwhite ethnicity, and glucocorticoid therapy for rejection and chronic immunosuppression with cyclosporine and especially tacrolimus. The pathophysiology of this condition resembles that of type 2 diabetes mellitus: pretransplantation end-stage liver/renal and heart disease are insulin-resistant states, and after transplantation, glucocorticoids induce further peripheral insulin insensitivity. The "second hit" appears to be an acquired (yet reversible) insulin secretion defect resulting from the calcineurin inhibitors cyclosporine and tacrolimus. An international panel of experts has recently published the proceeding of a Consensus Conference proposing strategies for the screening, prevention and management of PTDM. Future directions include pre- and post-transplantation glucose load testing for high-risk individuals and pharmacological agents to decrease insulin resistance and to preserve beta-cell function.

Update on liver transplantation using cyclosporine

After the introduction of cyclosporine into liver transplantation in 1983, 1-year patient survival more than doubled. Later, with the improved microemulsified formulation of cyclosporine (Neoral) more stable pharmacokinetics were achieved. Today, C(2) monitoring of cyclosporine blood levels allows a more accurate estimation of the area under the concentration-versus-time curve as the single best indicator of cyclosporine exposure. As a consequence, with better control of side effects as well as desired effects the results of cyclosporine in liver transplantation have been further improved. The introduction of mycophenolate mofetil and basiliximab/daclizumab combination therapy has provided new options for the prevention of allograft rejection. The safety profile of individual immunosuppressive regimens comes more into focus since acute allograft rejection may be controlled successfully with competing strategies. As the focus in liver transplantation is shifting toward greatly improved long-term results, late posttransplant mortality with a functioning graft is a major concern. Prevention of long-term complications associated with highly effective immunosuppressants--posttransplant lymphoproliferative disease, cytomegalovirus infection, diabetes, hypertension, and hyperlipidemia-gains importance. Technical advances in living-related and cadaveric split-liver transplantation have lead to increasing use of segmental liver transplantation with the need to consider the effects of immunosuppression on liver regeneration and metabolism. The individualized orchestration of immunosuppression taking into account the underlying liver disease as well as other individual predispositions remains a future challenge.

Non-alcoholic fatty liver disease, non-alcoholic steatohepatitis and orthotopic liver transplantation

Obesity, non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are becoming increasingly common medical problems in the developed world, often in the setting of the metabolic or insulin resistance syndrome (IRS). It is predicted that by the year 2025 > 25 million Americans may have NASH-related liver disease. NASH and NAFLD also affect the donor population. The use of steatotic donor livers for liver transplantation (LT) is associated with an increased risk of primary nonfunction (PNF) in the allograft. There is particular reluctance to use steatotic livers for living donor LT. There is indirect evidence to suggest that patients undergoing LT for cirrhosis resulting from NASH may have poorer outcome, despite careful selection of LT candidates. Indeed it is likely that many potential LT candidates with NASH are excluded from LT due to co-morbid conditions related to IRS. The post-LT patient is at risk of several components of IRS, such as diabetes mellitus, hypertension, hyperlipidaemia and obesity and there is increasing recognition of de novo and recurrent NAFLD and NASH after LT. Thus NAFLD and NASH affect all aspects of LT including donors, patients in evaluation and the LT recipient.

Prevalence of gingival overgrowth in transplant patients immunosuppressed with tacrolimus

AIMS

The study aims to determine the prevalence and severity of gingival overgrowth in a group of adult organ transplant recipients immunosuppressed with tacrolimus in comparison with ciclosporin, and to examine various risk factors for the development of gingival overgrowth.

METHODS

Forty patients taking tacrolimus were compared with 197 ciclosporin patients. Demographic, pharmacological and periodontal data were recorded for all patients. Comparison between the groups was made using independent sample t-tests, chi2 statistic or Mann-Whitney test. The effects of risk variables on overgrowth severity were examined using forward and backward stepwise regression analysis.

RESULTS

Those taking tacrolimus had a significantly lower mean gingival overgrowth score (14.1%) compared with ciclosporin (22.4%). Fifteen percent of the tacrolimus group had clinically significant gingival overgrowth compared with 30% in the ciclosporin group (p=0.053).

CONCLUSIONS

The prevalence and severity of gingival overgrowth is less in adult transplant patients taking tacrolimus compared with ciclosporin. Concomitant use of calcium channel blockers and previous medication with ciclosporin are significant risk factors for the presence and severity of gingival overgrowth. Patients who have alteration of their immunosuppressant from ciclosporin to tacrolimus may persist in demonstrating gingival overgrowth attributable to their ongoing therapy with calcium channel blockers.

Tacrolimus: a further update of its use in the management of organ transplantation

Extensive clinical use has confirmed that tacrolimus (Prograf) is a key option for immunosuppression after transplantation. In large, prospective, randomised, multicentre trials in adults and children receiving solid organ transplants, tacrolimus was at least as effective or provided better efficacy than cyclosporin microemulsion in terms of patient and graft survival, treatment failure rates and the incidence of biopsy-proven acute and corticosteroid-resistant rejection episodes. Notably, the lower incidence of rejection episodes after renal transplantation in tacrolimus recipients was reflected in improved cost effectiveness. In bone marrow transplant (BMT) recipients, the incidence of tacrolimus grade II-IV graft-versus-host disease was significantly lower with tacrolimus than cyclosporin treatment. Efficacy was maintained in renal and liver transplant recipients after total withdrawal of corticosteroid therapy from tacrolimus-based immunosuppression, with the incidence of acute rejection episodes at up to 2 years' follow-up being similar with or without corticosteroids. Tacrolimus provided effective rescue therapy in transplant recipients with persistent acute or chronic allograft rejection or drug-related toxicity associated with cyclosporin treatment. Typically, conversion to tacrolimus reversed rejection episodes and/or improved the tolerability profile, particularly in terms of reduced hyperlipidaemia. In lung transplant recipients with obliterative bronchiolitis, conversion to tacrolimus reduced the decline in and/or improved lung function in terms of forced expiratory volume in 1 second. Tolerability issues may be a factor when choosing a calcineurin inhibitor. Cyclosporin tends to be associated with a higher incidence of significant hypertension, hyperlipidaemia, hirsutism, gingivitis and gum hyperplasia, whereas the incidence of some types of neurotoxicity, disturbances in glucose metabolism, diarrhoea, pruritus and alopecia may be higher with tacrolimus treatment. Renal function, as assessed by serum creatinine levels and glomerular filtration rates, was better in tacrolimus than cyclosporin recipients at up to 5 years' follow-up.

CONCLUSION

Recent well designed trials have consolidated the place of tacrolimus as an important choice for primary immunosuppression in solid organ transplantation and in BMT. Notably, in adults and children receiving transplants, tacrolimus-based primary immunosuppression was at least as effective or provided better efficacy than cyclosporin microemulsion treatment in terms of patient and graft survival, treatment failure and the incidence of acute and corticosteroid-resistant rejection episodes. The reduced incidence of rejection episodes in renal transplant recipients receiving tacrolimus translated into a better cost effectiveness relative to cyclosporin microemulsion treatment. The optimal immunosuppression regimen is ultimately dependent on balancing such factors as the efficacy of the individual drugs, their tolerability, potential for drug interactions and pharmacoeconomic issues.

Malonyl-CoA signaling, lipid partitioning, and glucolipotoxicity: role in beta-cell adaptation and failure in the etiology of diabetes

Beta-cells possess inherent mechanisms to adapt to overnutrition and the prevailing concentrations of glucose, fatty acids, and other fuels to maintain glucose homeostasis. However, this is balanced by potentially harmful actions of the same nutrients. Both glucose and fatty acids may cause good/adaptive or evil/toxic actions on the beta-cell, depending on their concentrations and the time during which they are elevated. Chronic high glucose dramatically influences beta-cell lipid metabolism via substrate availability, changes in the activity and expression of enzymes of glucose and lipid metabolism, and modifications in the expression level of key transcription factors. We discuss here the emerging view that beta-cell "glucotoxicity" is in part indirectly caused by "lipotoxicity," and that beta-cell abnormalities will become particularly apparent when both glucose and circulating fatty acids are high. We support the concept that elevated glucose and fatty acids synergize in causing toxicity in islets and other organs, a process that may be instrumental in the pleiotropic defects associated with the metabolic syndrome and type 1 and type 2 diabetes. The mechanisms by which hyperglycemia and hyperlipidemia alter insulin secretion are discussed and a model of beta-cell "glucolipotoxicity" that implicates alterations in beta-cell malonyl-CoA concentrations; peroxisome proliferator-activated receptor-alpha and -gamma and sterol regulatory element binding protein-1c expression; and lipid partitioning is proposed.

Thiazolidinedione therapy in a patient with diabetes after cardiac transplantation

OBJECTIVE

To describe the successful use of a thiazolidinedione agent for the treatment of diabetes diagnosed after heart transplantation.

METHODS

We present a case report of a 51-year-old woman who underwent cardiac transplantation because of cardiomyopathy; diabetes developed 6 months later. Her clinical course and serial laboratory findings are documented as insulin therapy was initiated and subsequently transitioned to rosiglitazone during maintenance of the immunosuppressive regimen.

RESULTS

After rosiglitazone therapy was instituted, the patient's insulin dose was gradually tapered and eventually stopped. Target glycemic control was maintained without apparent aggravation of cardiac function or volume overload. No deleterious effects on other organ systems or interactions with the antirejection medications were noted during close follow-up.

CONCLUSION

Rosiglitazone may be safe and effective therapy for patients with posttransplantation diabetes. Rosiglitazone also helps to counteract the insulin-resistant state and reduces or eliminates the need for exogenous insulin. Further studies should attempt to confirm the usefulness of treatment with thiazolidinediones for patients with diabetes after organ transplantation.

New immunosuppressive drugs: an update

An increasing number of immunosuppressive drugs became available for clinical use over the past few decades. These include substances with recently recognized immunosuppressive properties, which needed careful evaluation in various trials before they could be approved for use in different diseases. The effectiveness of other agents was already established, but knowledge about their modes of action or the mechanisms that lead to side effects was acquired much later. This understanding also contributed to the development of new drugs that display synergistic effects or lack certain adverse effects. The greater choice afforded by such research endeavours allows us to select the best therapeutic strategy for an individual patient; however, this requires a comprehensive knowledge of the available options. The present review provides an update of current knowledge of the most important substances (including calcineurin and target of rapamycin inhibitors, regulators of gene expression, and inhibitors of purine and pyrimidine synthesis) and surveys some of the novel agents that are expected to play an important role in the future.