Protopic
The interaction between FK778 and tacrolimus in the prevention of rat cardiac allograft rejection is dose dependent.

Deuse T, Schrepfer S, Reichenspurner H.

Department of Cardiovascular Surgery, University Hospital Hamburg-Eppendorf, Hamburg, Germany.

OBJECTIVE: The synthetic malononitrilamide FK778 inhibits T- and B-cell responsiveness, phagocyte effector function, exerts inhibitory activity against cytomegalovirus, and is thus one of the most promising new immunosuppressive drugs. The aim of this study was to evaluate the combination of FK778 and tacrolimus in a high-responder rat cardiac transplantation model. METHODS: The Brown Norway-Lewis rat strain combination was used to investigate graft survival after 10 days of posttransplant oral therapy with FK778 (5 or 20 mg/kg), tacrolimus (2 or 8 mg/kg), or combination regimens at varying doses (5+2 mg/kg, 10+1 mg/kg, or 20+8 mg/kg). Grafts were harvested after cessation of cardiac contractions. Combination indices (CI) were calculated for drug combinations. RESULTS: In untreated recipients, allograft survival was 6.2+/-0.4 days. FK778 at 20 mg/kg and tacrolimus at 2 or 8 mg/kg significantly prolonged graft survival to a mean survival time (MST) of 17.0+/-2.8, 18.5+/-2.7, and 25.0+/-2.5 days, respectively. The two low-dose drug combinations achieved a graft survival of 23.2+/-2.9 and 25.2+/-3.1 days, which was significantly longer compared with FK778 at 5 mg/kg, FK778 at 20 mg/kg, and tacrolimus at 2 mg/kg (P </=0.003) and was similar to that of high-dose tacrolimus therapy (8 mg/kg). The drugs showed synergistic interactions (CI values of 0.62 and 0.52, respectively). With the high-dose drug combination, MST was 30.0+/-4.1 days, which was significantly longer compared with all other groups (P </=0.012). However, drugs showed only additive interaction (CI=0.95), and recipients suffered enhanced toxic side effects. CONCLUSIONS: This study provides evidence that FK778 and tacrolimus show supportive interaction in their immunosuppressive potency that is synergistic in low-dose combinations and additive in higher doses.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15084926&dopt=Abstract tacrolimus Protopic



Protopic
Determination of the effect of calcineurin inhibitors on the rat's immune system after KLH immunisation.

Roman D, Ulrich P, Paul G, Court M, Vit P, Kehren J, Mahl A.

Novartis Pharma AG, Preclinical Safety, Basel, Switzerland. danielle.roman pharma.novartis.com

The calcineurin inhibitors cyclosporin A (CsA), tacrolimus (FK506) and pimecrolimus (ASM981) are on the market for the oral treatment of psoriasis and atopic dermatitis and topical treatment of atopic dermatitis, respectively. The effect of these treatments on the immune response was investigated in this study after immunisation of rats with keyhole limpet hemocyanin (KLH). Male rats (10 per group) were orally administered pimecrolimus at 10 or 30 mg/kg/day), tacrolimus at 3 mg/kg/day or CsA at 20 mg/kg/day for 4 weeks. Control animals similarly received the vehicle only. The last five animals per group were immunised and challenged with KLH on days 16 and 24, respectively. Eight days after the last injection, the immune function was investigated by detecting KLH-specific antibodies in the serum and by examination of cell infiltration at the site of the KLH-challenge. In addition, a correlation between functional and structural changes was established by quantification of lymphocyte sub-populations in the blood or residing in lymphatic tissue. In KLH-immunised rats, CsA caused complete suppression of the KLH-specific IgM and IgG production, whereas only IgG production was affected by pimecrolimus at 30 mg/kg/day and more so by tacrolimus at 3 mg/kg/day. Immunophenotyping of lymphocyte sub-populations in spleen and lymph node indicated a decrease in T lymphocytes with pimecrolimus at 30 mg/kg/day, tacrolimus and CsA, whereas these changes were marginal for pimecrolimus at 10 mg/kg/day. Immunophenotyping of peripheral white blood cells (WBC) revealed a decrease in the absolute number of T lymphocytes with all three test items. In comparison with non-immunised animals, a slight increase in absolute numbers of T lymphocytes was observed in KLH-immunised animals treated with pimecrolimus at 10 or 30 mg/kg/day. In conclusion, the ability of the immune system to respond to KLH was not affected by pimecrolimus at 10 mg/kg/day whereas a decrease in immune function was noted in the other groups as follows: pimecrolimus (30 mg/kg/day) < tacrolimus (3 mg/kg/day) < CsA (20 mg/kg/day).

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15093258&dopt=Abstract tacrolimus Protopic



Protopic
Induction of rosaceiform dermatitis during treatment of facial inflammatory dermatoses with tacrolimus ointment.

Antille C, Saurat JH, Lubbe J.

Department of Dermatology, University Hospital, Geneva, Switzerland.

BACKGROUND: Tacrolimus ointment is increasingly used for anti-inflammatory treatment of sensitive areas such as the face, and recent observations indicate that the treatment is effective in steroid-aggravated rosacea and perioral dermatitis. We report on rosaceiform dermatitis as a complication of treatment with tacrolimus ointment. OBSERVATIONS: Six adult patients with inflammatory facial dermatoses were treated with tacrolimus ointment because of the ineffectiveness of standard treatments. Within 2 to 3 weeks of initially effective and well-tolerated treatment, 3 patients with a history of rosacea and 1 with a history of acne experienced sudden worsening with pustular rosaceiform lesions. Biopsy revealed an abundance of Demodex mites in 2 of these patients. In 1 patient with eyelid eczema, rosaceiform periocular dermatitis gradually appeared after 3 weeks of treatment. In 1 patient with atopic dermatitis, telangiectatic and papular rosacea insidiously appeared after 5 months of treatment. CONCLUSIONS: Our observations suggest that the spectrum of rosaceiform dermatitis as a complication of treatment with tacrolimus ointment is heterogeneous. A variety of factors, such as vasoactive properties of tacrolimus, proliferation of Demodex due to local immunosuppression, and the occlusive properties of the ointment, may be involved in the observed phenomena. Future studies are needed to identify individual risk factors.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15096374&dopt=Abstract tacrolimus Protopic



Protopic
Effect of calcineurin inhibitors on extracellular matrix turnover in isolated human glomeruli.

Esposito C, Foschi A, Parrilla B, Cornacchia F, Fasoli G, Plati AR, De Mauri A, Mazzullo T, Scudellaro R, Dal Canton A.

Unit of Nephrology, Dialysis and Transplantation, IRCCS Policlinico San Matteo, University of Pavia, Pavia, Italy. espositociro56 hotmail.com

INTRODUCTION: Although chronic cyclosporine toxicity is mainly characterized by tubular atrophy and interstitial fibrosis, glomerular injury with expansion of mesangial matrix and sclerosis is not uncommon. Tacrolimus is a newer calcineurin inhibitor that has been used in renal transplant recipients as primary or rescue therapy. Clinical trials suggest an improved long-term graft survival among patients treated with tacrolimus. Recently we have shown that tacrolimus and cyclosporine have similar effects on extracellular matrix turnover in cultured cells. The present study was performed to investigate the effects of the calcineurin inhibitors on whole glomeruli extracellular matrix turnover. METHODS: Human glomeruli isolated from kidney biopsies just before transplantation were incubated with culture media containing either cyclosporine (200 ng/mL) or tacrolimus (10 ng/mL) for 24 hours. Glomeruli incubated only with culture medium were used as control. RESULTS: The expressions of (alpha2)IV collagen, metalloprotease 9 (MMP9), tissue inhibitors of metalloproteases 2 (TIMP-2), and TGFbeta were evaluated by in situ reverse transcription and polymerase chain reactions (RT-PCR). beta-actin was used as a control gene. Cyclosporine (but not tacrolimus) increased the expression of (alpha2)IV collagen and TIMP2 in isolated glomeruli. TGF-beta was markedly increased by cyclosporine. MMP9 expression was not affected by the calcineurin inhibitors. By light microscopy kidney biopsies did not show pathologic changes. CONCLUSION: Cyclosporine treatment modulates extracellular matrix turnover in isolated human glomeruli, inducing an imbalance between synthesis and degradation. This effect, not observed in tacrolimus-treated human glomeruli, may induce the extracellular matrix deposition and sclerosis characteristic of chronic cyclosporine toxicity.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15110634&dopt=Abstract tacrolimus Protopic



Protopic
Liquid chromatography-negative ion electrospray tandem mass spectrometry method for the quantification of tacrolimus in human plasma and its bioanalytical applications.

Ramakrishna NV, Vishwottam KN, Puran S, Manoj S, Santosh M, Wishu S, Koteshwara M, Chidambara J, Gopinadh B, Sumatha B.

Biopharmaceutical Research, Suven Life Sciences Ltd., Serene Chambers, Hyderabad 500 034, India. nvsrk suven.com

A simple, rapid, novel and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of tacrolimus (I) in human plasma, a narrow therapeutic index, potent macrolide immunosuppressive drug. The analyte and internal standard (tamsulosin (II)) were extracted by liquid-liquid extraction with t-butylmethylether using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on reverse phase Xterra ODS column with a mobile phase of 99% methanol and 1% 10mM ammonium acetate buffer. The deprotonate of analyte was quantitated in negative ionization by multiple reaction monitoring (MRM) with a mass spectrometer. The mass transitions m/z 802.5-->560.3 and m/z 407.2-->151.9 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.05-25ng/ml for tacrolimus in human plasma. The lower limit of quantitation was 50pg/ml with a relative standard deviation of less than 20%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. Run time of 2min for each sample made it possible to analyze a throughput of more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in comparative bioavailability studies. The tacrolimus plasma concentration profile could be obtained for pharmacokinetic study. The observed maximum plasma concentration (C(max)) of tacrolimus (5mg oral dose) is 440pg/ml, time to observed maximum plasma concentration (T(max)) is 2.5h and elimination half-life (T(1/2)) is 21h.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15113534&dopt=Abstract tacrolimus Protopic



Protopic
Effect of tacrolimus on the expression of macrophage scavenger and nuclear hormone receptors in THP-1-derived human macrophages.

Jin S, Mathis AS, Gioia K, Minko T, Friedman GS, Rosenblatt J, Peng F, Serur DS, Knipp GT.

Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA.

BACKGROUND: Data indicate that tacrolimus and cyclosporine A (CsA) differentially affect the risk of atherosclerosis. The results of our recent in vitro studies of clinically relevant CsA concentrations demonstrated the modulation of macrophage scavenger receptors (MSRs) involved in atherogenesis. This work evaluated the effects of clinically relevant tacrolimus concentrations on the expression of the MSR genes CD36 and CD68, SR-A and SR-BII, lectin-like oxidized low-density lipoprotein receptor-1, the nuclear hormone receptors peroxisome proliferator-activated receptor (PPAR)gamma and liver-X-receptor-alpha, and the cholesterol efflux pump ABCA1 in the in vitro human THP-1 macrophage model. METHODS: The cells were cultured and differentiated into macrophages. Macrophages were treated with the tacrolimus to assess gene expression in a time-dependent (1, 2, 4, 8, and 24 hr) and dose-dependent (concentrations [micrograms/liter] corresponding to the trough [15], peak [30], and 4 x peak [120]) manner using reverse-transcriptase polymerase chain reactions. The gene expression levels of interest were normalized to GAPDH expression in each sample to provide semiquantitative reverse-transcriptase polymerase chain reaction results. Additional immunoblotting studies demonstrated protein expression of CD36, PPARgamma, and ABCA1. RESULTS.: The gene expression of CD36, SR-BII, and lectin-like oxidized low-density lipoprotein receptor-1 were down-regulated, and ABCA1 was up-regulated. CD68, SR-AI, liver-X-receptor-alpha, and PPARgamma were regulated in a dose-dependent manner. Protein expression of CD36 was down-regulated, and PPARgamma and ABCA1 were relatively unchanged. CONCLUSIONS: Tacrolimus seems to regulate MSRs, nuclear hormone receptors, and ABCA1 in THP-1 macrophages. These results differ from previous findings with CsA and may provide insight into the mechanisms of posttransplant atherosclerosis.

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Protopic
Clinical efficacy and toxicity profile of tacrolimus and mycophenolic acid in relation to combined long-term pharmacokinetics in de novo renal allograft recipients.

Kuypers DR, Claes K, Evenepoel P, Maes B, Vanrenterghem Y.

Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Belgium. Dirk.Kuypers uz.kuleuven.ac.be

INTRODUCTION: Tacrolimus and mycophenolate mofetil are effective drugs characterized by specific toxicity profiles that may compromise their long-term use in renal transplant recipients. Clinicians, therefore, need reliable drug monitoring tools for relating efficacy and toxicity to drug exposure.Study design We conducted a prospective 12-month pharmacokinetic study of tacrolimus and mycophenolic acid in 100 de novo recipients. The aim was to examine whether tacrolimus and mycophenolic acid exposure parameters (predose trough blood concentration [C(0)], area under the concentration curve from 0 to 12 hours [AUC(0-12)], maximum blood or plasma concentration [C(max)], and dose) would reflect clinical efficacy and toxicity at different time points after transplantation (7 days, 6 weeks, and 3, 6, and 12 months). RESULTS: Initially, after grafting, the tacrolimus AUC(0-12) was higher in recipients with infection (P =.01 on day 7, P =.02 at week 6), whereas the mycophenolic acid AUC(0-12) was not different. There was no difference in tacrolimus exposure between patients who had arterial hypertension or hyperlipidemia and those who did not. Patients with tacrolimus nephrotoxicity received a higher drug dose (P =.03) and had higher drug clearance (P =.02). From 3 months, recipients with anemia or leukopenia had higher mycophenolic acid AUC(0-12) (anemia, P =.03 at month 3 and P =.01 at month 12; leukopenia, P =.01 at month 3 and P =.04 at 1 year) and C(0) (anemia, P =.001 at month 3 and P =.001 at month 12; leukopenia, P =.01 at month 3 and P =.04 at 1 year). Finally, for recipients who did not simultaneously have a target tacrolimus AUC(0-12) of 150 ng x h/mL and a mycophenolic acid AUC(0-12) of 45 mg x h/L by day 7, the incidence of acute rejection tended to be higher (26.3%) compared with patients who reached both target values (7.7%) (P =.07). CONCLUSIONS: Pharmacokinetic exposure parameters of tacrolimus and mycophenolic acid are related to specific drug-induced side effects in a time-dependent fashion. In addition, this study has provided a conceptual basis for defining a combined target therapeutic window for tacrolimus and mycophenolic acid based on sparse AUC(0-12) measurements.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15116056&dopt=Abstract tacrolimus Protopic