The effects of maintenance doses of FK506 versus cyclosporin A on glucose and lipid metabolism after orthotopic liver transplantation

Posttransplantation diabetes: a systematic review of the literature

OBJECTIVES

To systematically review the incidence of posttransplantation diabetes (PTD), risk factors for its development, prognostic implications, and optimal management.

RESEARCH DESIGN AND METHODS

We searched databases (MEDLINE, EMBASE, the Cochrane Library, and others) from inception to September 2000, reviewed bibliographies in reports retrieved, contacted transplantation experts, and reviewed specialty journals. Two reviewers independently determined report inclusion (original studies, in all languages, of PTD in adults with no history of diabetes before transplantation), assessed study methods, and extracted data using a standardized form. Meta-regression was used to explain between-study differences in incidence.

RESULTS

Nineteen studies with 3,611 patients were included. The 12-month cumulative incidence of PTD is lower (<10% in most studies) than it was 3 decades ago. The type of immunosuppression explained 74% of the variability in incidence (P = 0.0004). Risk factors were patient age, nonwhite ethnicity, glucocorticoid treatment for rejection, and immunosuppression with high-dose cyclosporine and tacrolimus. PTD was associated with decreased graft and patient survival in earlier studies; later studies showed improved outcomes. Randomized trials of treatment regimens have not been conducted.

CONCLUSIONS

Physicians should consider modification of immunosuppressive regimens to decrease the risk of PTD in high-risk transplant recipients. Randomized trials are needed to evaluate the use of oral glucose-lowering agents in transplant recipients, paying particular attention to interactions with immunosuppressive drugs.

Diabetogenic effect of tacrolimus in South African patients undergoing kidney transplantation1

BACKGROUND

Diabetes mellitus (DM) is a complication of tacrolimus therapy. This prospective study evaluated the prevalence of DM in South African black and white patients receiving tacrolimus after kidney transplantation and factors that could identify patients before transplantation who may be at risk of developing DM.

METHODS

Fasting blood samples from 17 patients (11 black, 6 white) were analyzed immediately pretransplantation and at 1 and 3 months posttransplantation for glucose, HbAIC, insulin, C-peptide, free fatty acids, lipids, urea, and creatinine. Insulin resistance (IR) was calculated using the homeostasis model assessment (HOMA) and quantitative insulin sensitivity check index (QUICKI) formulas.

RESULTS

Eight patients (47%) became diabetic (six black, two white), and nine patients (five black, four white) remained nondiabetic. Mean glucose concentrations in the diabetic group were significantly higher at 1 month (P=0.03) and 3 months (P=0.01). Mean insulin level was also significantly raised at 3 months (P=0.01) as was HbAIC (P=0.001). C-peptide concentrations did not change significantly in either group. Significant correlations emerged between fasting glucose concentrations at 3 months posttransplantation and initial HOMA (r=0.486; P=0.048) and initial QUICKI (r=-0.582; P=0.014).

CONCLUSIONS

Occurrence of DM was high and somewhat greater in black patients. IR was the main mechanism involved, together with inadequate beta-cell compensation. IR pretransplantation predicts the subsequent development of DM.

Long-term management of the liver transplant patient: diabetes, hyperlipidemia, and obesity

1. As long-term survival improves after liver transplantation, cardiovascular complications are emerging as a major cause of late morbidity and mortality. It seems reasonable to correct the potentially reversible cardiovascular risk factors of diabetes, hyperlipidemia, and obesity, in addition to hypertension. 2. The results of liver transplantation in diabetics are acceptable in terms of morbidity, mortality, and prevalence of posttransplant diabetes, but the poor outcomes described in some series suggest that more extensive testing for macro- and microvascular disease may become necessary. 3. The management of diabetes in liver transplant recipients is not substantially different from its management in non-transplant patients, except that steroid reduction or withdrawal and minimizing doses of calcineurin inhibitors are beneficial. 4. Hyperlipidemia occurs in all solid-organ transplantation, with prevalence rates the lowest for liver transplant recipients. Following liver transplantation, between 15% and 40% of recipients on average have increased plasma cholesterol levels and about 40% have hypertriglyceridemia. Dietary changes, weight reduction, exercise and statins are the mainstays of therapy. 5. Retrospective studies suggest that long-term survival of obese recipients after liver transplantation does not differ from nonobese recipients. Posttransplant weight gain occurs in most recipients, and approximately two thirds become overweight. The management of posttransplant obesity is similar to that in non-transplant settings.

Diminished insulin secretory response to glucose but normal insulin and glucagon secretory responses to arginine in a family with maternally inherited diabetes and deafness caused by mitochondrial tRNA(LEU(UUR)) gene mutation

OBJECTIVE

The effects of glucose, arginine, and glucagon on beta-cell function as well as alpha-cell response to arginine were studied in a family with mitochondrial diabetes.

RESEARCH DESIGN AND METHODS

The function of alpha- and beta-cells was assessed in all five siblings carrying the mitochondrial tRNA Leu(UUR) gene mutation at position 3243 and compared with six sex-, age-, and weight-matched control subjects. Insulin and C-peptide responses were evaluated by intravenous glucagon application, intravenous arginine stimulation test, and intravenous glucose tolerance test. Glucagon secretion was assessed during the arginine stimulation test.

RESULTS

The glucose disappearance constant (K(g)) value (mean +/- SEM 0.61 +/- 0.04 vs. 1.1 +/- 0.04, P = 0.0002) as well as the acute insulin response to glucose (area under the curve [AUC] 0-10 min, 77.7 +/- 50.7 vs. 1,352.3 +/- 191.5 pmol/l, P = 0.0004) were decreased in all patients. Similarly, glucagon-stimulated C-peptide response was also impaired (728 +/- 111.4 vs. 1,526.7 +/- 157.7 pmol/l, P = 0.005), whereas the insulin response to arginine (AUC) was normal (1,346.9 +/- 710.8 vs. 1,083.2 +/- 132.5 pmol/l, P = 0.699). Acute glucagon response to arginine (AUC) was normal but tended to be higher in the patients than in the control subjects (181.7 +/- 47.5 vs. 90.0 +/- 21.1 pmol/l, P = 0.099).

CONCLUSIONS

This study shows impaired insulin and C-peptide secretion in response to a glucose challenge and to glucagon stimulation in diabetic patients with mitochondrial tRNA Leu(UUR) gene mutation, although insulin and glucagon secretory responses to arginine were normal.

Late mortality after orthotopic liver transplantation

BACKGROUND

Mortality within the first year after orthotopic liver transplantation (OLTx) is usually due to infection or allograft failure. Late complications leading to death after OLTx have not been extensively evaluated. The aim of this study was to determine the incidence of late mortality and to identify the most common causes and risk factors associated with late mortality after OLTx.

METHODS

A total of 479 OLTx were performed in 459 patients (320 males, 139 females; mean age 47 years, range 13 to 69) between September 1991 and April 2000. All patient deaths among liver transplant recipients who survived more than 1 year after transplantation (follow-up mean 3.4 years, median 3, range 1 to 8.6) were reviewed.

RESULTS

In all, 122 allografts (24%) were lost in 109 patients during the study period (24%). Seventy-five allografts were lost in 69 patients by 1 year (15%). Forty-seven allografts were lost in 40 patients who survived at least 1 year (9.6%). Actuarial survivals at 2 years, 5 years, and 9 years were 95%, 85%, and 80%, respectively (based on 100% survival at 1 year). The causes of the late mortality were malignancy (9 patients), disease recurrence (8), late infection (6), renal failure complications (5), cardiovascular complications (4), chronic rejection (3), gastrointestinal hemorrhage (2), medication noncompliance (1), and unknown (2).

CONCLUSIONS

Malignancy and disease recurrence are the major causes of late mortality among adult OLTx recipients. Pharmacologic immunosuppression is associated with many of the causes of late mortality. Advances in immunosuppression with less toxicity may improve long-term survival after OLTx.

Influence of tacrolimus on glucose metabolism before and after renal transplantation: a prospective study

Most studies concerning the influence of tacrolimus on glucose metabolism have been performed either in animals or after organ transplantation. These clinical studies have largely been transversal with patients who were using steroids. Therefore, this prospective, longitudinal study investigated the influence of tacrolimus on glucose metabolism before and after transplantation. Eighteen Caucasian dialysis patients underwent an intravenous glucose tolerance test before and 5 d after the start of tacrolimus. Insulin sensitivity index (k(G)), insulin resistance (insulin/glucose ratio and homeostasis model assessment), and C-peptide and insulin secretion were calculated. Trough levels of tacrolimus were measured. After transplantation, the occurrence of posttransplantation diabetes mellitus (PTDM) was prospectively monitored. Statistical analysis was performed using the Wilcoxon signed ranks test and Spearman's rho for correlation. Before tacrolimus, k(G) was indeterminate in three patients. During tacrolimus, k(G) decreased in 16 of 18 patients, from a median of 1.74 mmol/L per min to 1.08 mmol/L per min (P<0.0001). The correlation between C-peptide and insulin data was excellent. Insulin secretion decreased from 851.0 mU x min/L to 558.0 mU x min/L (P = 0.014), whereas insulin resistance did not change. Insulin sensitivity correlated negatively with tacrolimus trough level. After transplantation, three patients developed PTDM; before tacrolimus, two had an indeterminate and one a low normal k(G). During tacrolimus administration, k(G) decreased in almost all patients as a result of a diminished insulin secretion response to a glucose load, whereas insulin resistance did not change. Patients with an abnormal or indeterminate k(G) seem to be at risk of developing PTDM while on tacrolimus.

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

Tacrolimus (FK-506) is an immunosuppressant agent that acts by a variety of different mechanisms which include inhibition of calcineurin. It is used as a therapeutic alternative to cyclosporin, and therefore represents a cornerstone of immunosuppressive therapy in organ transplant recipients. Tacrolimus is now well established for primary immunosuppression in liver and kidney transplantation, and experience with its use in other types of solid organ transplantation, including heart, lung, pancreas and intestinal, as well as its use for the prevention of graft-versus-host disease in allogeneic bone marrow transplantation (BMT), is rapidly accumulating. Large randomised nonblind multicentre studies conducted in the US and Europe in both liver and kidney transplantation showed similar patient and graft survival rates between treatment groups (although rates were numerically higher with tacrolimus- versus cyclosporin-based immunosuppression in adults with liver transplants), and a consistent statistically significant advantage for tacrolimus with respect to acute rejection rate. Chronic rejection rates were also significantly lower with tacrolimus in a large randomised liver transplantation trial, and a trend towards a lower rate of chronic rejection was noted with tacrolimus in a large multicentre renal transplantation study. In general, a similar trend in overall efficacy has been demonstrated in a number of additional clinical trials comparing tacrolimus- with cyclosporin-based immunosuppression in various types of transplantation. One notable exception is in BMT, where a large randomised trial showed significantly better 2-year patient survival with cyclosporin over tacrolimus, which was primarily attributed to patients with advanced haematological malignancies at the time of (matched sibling donor) BMT. These survival results in BMT require further elucidation. Tacrolimus has also demonstrated efficacy in various types of transplantation as rescue therapy in patients who experience persistent acute rejection (or significant adverse effect's) with cyclosporin-based therapy, whereas cyclosporin has not demonstrated a similar capacity to reverse refractory acute rejection. A corticosteroid-sparing effect has been demonstrated in several studies with tacrolimus, which may be a particularly useful consideration in children receiving transplants. The differences in the tolerability profiles of tacrolimus and cyclosporin may well be an influential factor in selecting the optimal treatment for patients undergoing organ transplantation. Although both drugs have a similar degree of nephrotoxicity, cyclosporin has a higher incidence of significant hypertension, hypercholesterolaemia, hirsutism and gingival hyperplasia, while tacrolimus has a higher incidence of diabetes mellitus, some types of neurotoxicity (e.g. tremor, paraesthesia), diarrhoea and alopecia.

CONCLUSION

Tacrolimus is an important therapeutic option for the optimal individualisation of immunosuppressive therapy in transplant recipients.