Protopic
Glucose metabolism in renal transplant recipients on tacrolimus: the effect of steroid withdrawal and tacrolimus trough level reduction.

Boots JM, van Duijnhoven EM, Christiaans MH, Wolffenbuttel BH, van Hooff JP.

Department of Internal Medicine, University Hospital Maastricht, Maastricht, The Netherlands.

The relative role of steroids and tacrolimus in the development of glucose metabolic disorders and hyperlipidemia after renal transplantation has not yet been clearly established. Therefore, glucose metabolism was prospectively evaluated by intravenous glucose tolerance test, as was lipid profile, in fifteen white nondiabetic renal transplant recipients three times: before and after steroid withdrawal and after tacrolimus trough level reduction. After withdrawal of 10 mg of prednisolone, insulin resistance decreased (fasting C-peptide, 0.99 to 0.77 nmol/L [P < 0.0009]; fasting insulin, 9.5 to 8.1 mU/L [P = 0.09]; insulin/glucose ratio, 1.85 to 1.45 mU/mmol [P = 0.10]) and lipid levels decreased (total cholesterol, 5.1 to 4.2 mmol/L [P = 0.006]); HDL cholesterol, 1.4 to 1.1 mmol/L [P = 0.01]; LDL cholesterol, 3.0 to 2.5 mmol/L [P = 0.15]; triglycerides, 1.52 to 0.91 mmol/L [P = 0.02]). After tacrolimus trough level reduction from 9.5 to 6.4 ng/ml, pancreatic beta-cell secretion capacity improved (C-peptide secretion increased from 49.0 to 66.6 nmol x min/L [P = 0.04] and insulin secretion increased from 1134 to 1403 mU x min/L [P = 0.06]). HbA1c improved also, from 5.9 to 5.3% (P = 0.002). Lipids did not change. In conclusion, steroid withdrawal resulted in a decrease in insulin resistance and a reduction in lipids, and tacrolimus trough level reduction resulted in an improved pancreatic beta-cell secretion capacity. Therefore, these therapeutic measurements may contribute to the reduction of the cardiovascular morbidity and mortality in renal transplant recipients.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11752041&dopt=Abstract tacrolimus Protopic



Protopic
Higher intracerebral concentration of tacrolimus after intermittent than continuous administration to rats.

Sakamoto Y, Makuuchi M, Harihara Y, Imamura H, Sato H.

Division of Surgery, Artificial Organ and Transplantation Surgery, Graduate School of Medicine, University of Tokyo, Japan.

Neurotoxicity associated with tacrolimus after liver transplantation is a serious problem. The optimal way to administer tacrolimus to reduce neurotoxicity remains to be clarified. Three groups of rats were administered tacrolimus for 2 weeks: group C, continuous intravenous infusion (0.25, 0.5, and 1.0 mg/kg/d); group I, intermittent intravenous bolus injection twice daily (0.25, 0.5, and 1.0 mg/kg/d); and group O, oral administration twice daily (5 mg/kg/d; n = 12 each). Rats were killed either day 7 or 14 to measure whole-blood and intracerebral trough concentrations of tacrolimus. The area under the whole-blood concentration-time curve (AUC) was determined day 7. The relative risk ratio of neurotoxicity was evaluated on the basis of the brain to blood concentration ratio (Kp) and intracerebral concentration to AUC ratio (R(AUC)). The whole-blood concentration of tacrolimus and AUC value were greater in group C than group I. Conversely, the intracerebral concentration and Kp and R(AUC) values were significantly greater in group I than group C. The difference in Kp values between groups C and I significantly increased with the dose and duration of administration. Whole-blood and intracerebral concentrations in group O were similar to those at the 0.25-mg/kg/d dose in group I. In conclusion, the intracerebral concentration of tacrolimus was greater after intermittent than continuous administration of the drug. Continuous administration of tacrolimus might be more advantageous than the intermittent method to reduce the intracerebral concentration and neurotoxicity.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11753909&dopt=Abstract tacrolimus Protopic



Protopic
Factors affecting the pharmacokinetics of tacrolimus (FK506) in hematopoietic cell transplant (HCT) patients.

Jacobson P, Ng J, Ratanatharathorn V, Uberti J, Brundage RC.

Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA.

Tacrolimus is an immunosuppressant commonly used in the prevention of graft-versus-host disease (GVHD) following allogeneic HCT. Unfortunately, the use of tacrolimus is associated with variable immunosuppression and toxicity. The purpose of this study was to describe tacrolimus population pharmacokinetic parameters, to identify relationships between clinical covariates and pharmacokinetic estimates, and to develop a model to predict tacrolimus clearance in HCT patients. Steady-state whole blood tacrolimus concentrations (n = 1625) obtained during intravenous and oral therapy were analyzed in 122 patients. Population clearance (CL) was 5.22 l/h and bioavailability (F) was 0.28. The influence of clinical covariates on population estimates of CL and F of tacrolimus were tested with nonlinear mixed effects models (NONMEM). CL was significantly reduced by elevations in total bilirubin 2.0-9.9 mg/dl (CL * 0.797), bilirubin > or = 10 mg/dl (CL * 0.581), serum creatinine > or = 2 mg/dl (CL * 0.587), grade III/IV graft-versus-host disease (CL * 0.814) and veno-occlusive disease (CL 0.814). No covariates were predictive of oral F. The interindividual variabilities in CL and F were 33% and 44%, respectively. Residual variability was 27.5% and 16.8% at tacrolimus concentrations of 10 microg/l and 20 microg/l, respectively. These models may be used to predict tacrolimus clearance and doses in adult patients following HCT.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11781626&dopt=Abstract tacrolimus Protopic



Protopic
Tacrolimus, cyclosporine and plasma lipoproteins in renal transplant recipients.

Venkiteswaran K, Sgoutas DS, Santanam N, Neylan JF.

Department of Pathology and Laboratory Medicine, Emory University Hospital, Room F147, 1364 Clifton Road, N. E., Atlanta, GA 30322, USA. dsgouta emory.edu

To compare the effect of tacrolimus (FK506) and cyclosporine (CsA) on plasma lipoproteins in renal transplant recipients receiving maintainance therapy, the following prospective study was undertaken. Blood from nineteen recipients on tacrolimus (FK group) and from twenty-one on CsA (CsA group) was collected at baseline, 3-, 6-, and 10-month intervals. Plasma lipids, lipoproteins and oxidation properties of lipoproteins were determined. Plasma total cholesterol, low density lipoprotein (LDL) cholesterol, and apolipoprotein B (apoB) were substantially increased in both groups, although only the CsA group showed significant differences at all time intervals and at the baseline. High density lipoprotein cholesterol, triglycerides, and apolipoprotein A varied in both groups at time intervals from the baseline, but not significantly. The susceptibility to oxidation of LDL isolated from the FK group at all times was uninfluenced by the tacrolimus treatment, and values were comparable to those obtained from LDL isolated from healthy individuals. A significantly higher susceptibility to oxidation as indicated by the shorter time required to start the formation of conjugated dienes was observed in LDL isolated from the CsA group at 3 and at 6 months of therapy. Tacrolimus-treated patients appear to have less hyperlipidemic and have LDL less susceptible to oxidation than patients treated with CsA.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11793038&dopt=Abstract tacrolimus Protopic



Protopic
Tacrolimus rescue therapy for children with acute renal transplant rejection.

Hymes LC, Warshaw BL.

Department of Pediatrics, Emory University, Atlanta, GA 30322, USA. Lhymes emory.edu

Seventeen children with renal transplants (11 living-related, age 2-18 years) were converted from cyclosporine to tacrolimus because of acute rejection that failed to respond to high-dose corticosteroids. Resistance to corticosteroids was confirmed by renal biopsy in 14 patients, and assumed in 3 patients because of failure of serum creatinine to improve to baseline values. Four patients were also treated with OKT3, and 15 children had been receiving mycophenolate maintenance therapy prior to conversion to tacrolimus. Rejection occurred at 2-174 weeks post transplant (mean 52 weeks). Actuarial 1- and 2-year graft survival was 87% and 78%. Three children progressed to end-stage renal disease after 4, 12, and 13 months of tacrolimus. The remaining 14 children have functioning allografts after 20-168 weeks of treatment (mean 80 weeks). All 14 children exhibit stable or improved renal function: serum creatinine 1.1+/-0.7 mg/dl versus 2.0+/-0.9 mg/dl prior to tacrolimus. In conclusion, tacrolimus was effective therapy for both early and late acute rejection in children who failed to respond to high-dose corticosteroids. No significant short-term adverse effects were encountered.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11793086&dopt=Abstract tacrolimus Protopic



Protopic
Evidence for a role of nuclear factor-kappaB in acute hypovolemic hemorrhagic shock.

Altavilla D, Saitta A, Squadrito G, Galeano M, Venuti SF, Guarini S, Bazzani C, Bertolini A, Caputi AP, Squadrito F.

University of Messina, Azienda Ospedaliera Universitaria "G. Martino," Messina, Italy.

BACKGROUND: In acute hypovolemic shock, a rapid systemic release of the inflammatory cytokine tumor necrosis factor (TNF-alpha) contributes to vascular failure. Nuclear factor kappaB (NF-kappaB) is an ubiquitous rapid-response transcription factor involved in inflammatory reactions and exerts its effect by expressing cytokines, chemokines, and cell adhesion molecules. The purpose of this study was to evaluate the role of NF-kappaB in acute hypovolemic hemorrhagic shock. METHODS: Hemorrhagic shock was induced in anesthetized male rats by intermittently withdrawing blood from an iliac catheter for 20 minutes (bleeding period) until mean arterial blood pressure (MAP) decreased and stabilized within the range of 20 to 30 mm Hg. Two minutes after bleeding was discontinued the rats received tacrolimus (100 microg/kg), an inhibitor of NF-kappaB activation, or its vehicle. We then evaluated survival rate and survival time, liver NF-kappaB activation by means of electrophoretic mobility shift assay, liver IkappaBalpha protein in the cytoplasm, hepatic TNF-alpha messenger RNA expression, plasma TNF-alpha, arterial blood pressure, and the contractile response of aortic rings to phenylephrine. RESULTS: Rats that underwent hemorrhagic shock died 28+/-2 minutes after bleeding was discontinued, experienced marked hypotension (MAP, 20-30 mm Hg), and had enhanced plasma levels of TNF-alpha (218 +/- 28 pg/mL 20 minutes after bleeding was discontinued). Aortas taken 20 minutes after bleeding was discontinued in rats that underwent hemorrhagic shock showed marked hyporeactivity to phenylephrine (1 nmol/L-10 micromol/L) compared with aortas harvested from sham shocked rats. Rats that underwent hemorrhagic shock also had increased levels of TNF-alpha messenger RNA in the liver. Furthermore, electrophoretic mobility shift assay showed that liver NF-kappaB binding activity increased in the nucleus, and Western blot analysis suggested that the levels of inhibitory IkappaBalpha protein in the cytoplasm decreased. Tacrolimus (100 microg/kg, administered 2 minutes after bleeding was discontinued) inhibited the loss of IkappaBalpha protein from the cytoplasm and prevented NF-kappaB binding activity in the nucleus. Moreover, tacrolimus increased survival time (118 +/- 7 minutes; P <.01) and survival rate (vehicle = 0 and tacrolimus = 90% 240 minutes after bleeding was discontinued), reverted the marked hypotension, decreased liver messenger RNA for TNF-alpha reduced plasma TNF-alpha (35 +/- 6 pg/mL), and restored the hyporeactivity to phenylephrine to control values. CONCLUSIONS: Our results suggest that acute blood loss (50% of the estimated total blood volume during a 20-minute period) causes activation of NF-kappaB and that tacrolimus, by inhibiting this transcription factor, protects against acute hypovolemic shock.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11812963&dopt=Abstract tacrolimus Protopic



Protopic
A prospective study of rapid corticosteroid elimination in simultaneous pancreas-kidney transplantation: comparison of two maintenance immunosuppression protocols: tacrolimus/mycophenolate mofetil versus tacrolimus/sirolimus.

Kaufman DB, Leventhal JR, Koffron AJ, Gallon LG, Parker MA, Fryer JP, Abecassis MM, Stuart FP.

Department of Surgery, Division of Transplantation, Northwestern University Medical School, 675 N. St. Clair Street, Galter Pavilion, Suite 17-200, Chicago, IL 60611, USA.

BACKGROUND: We examined the feasibility of rapid corticosteroid elimination in simultaneous pancreas kidney transplantation. METHODS: Forty consecutive simultaneous pancreas-kidney (SPK) transplant recipients were enrolled in a prospective study in which antithymocyte globulin induction and 6 days of corticosteroids were administered along with tacrolimus and MMF (n=20) or tacrolimus and sirolimus (n=20). Mean+/-SD follow-up for recipients receiving tacrolimus/MMF and tacrolimus/sirolimus were 12.7+/-3.9 and 13.4+/-2.9 months, respectively. Patient and graft survival, and rejection rates were compared to an historical control group (n=86; mean follow-up 41.5+/-15.4 months) of SPK recipients that received induction and tacrolimus, MMF, and corticosteroids. RESULTS: Demographic characteristics of recipient and donor variables were similar among all groups. The 1-year actuarial patient, kidney, and pancreas survival rates in the 40 SPK transplant recipients with rapid corticosteroid elimination were 100, 100, and 100%, respectively. In the historical control group the 1-year actual patient, kidney, and pancreas survival rates were 96.5, 93.0, and 91.9%, respectively. The 1-year rejection-free survival rate recipients in the rapid steroid elimination group collectively was 97.5 vs 80.2% in the historical control group (P=0.034). At 6 and 12 months posttransplant the serum creatinine values remained stable in all groups. CONCLUSIONS: We conclude that chronic corticosteroid exposure is not required in SPK transplant recipients receiving antithymocyte globulin induction and maintenance immuno-suppression consisting of either tacrolimus and mycophenolate mofetil or tacrolimus and sirolimus.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11821726&dopt=Abstract tacrolimus Protopic