Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42345 (mTOR)
 26,049 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Calcineurin inhibitors have dramatically improved the outcomes of pediatric liver transplantation. However, calcineurin inhibitor use is associated with a 50% reduction in glomerular filtration rate in the first year post-transplant. Nephrotoxicity can be difficult to manage, especially in the pediatric population. We hypothesized that the addition of an mTOR inhibitor with decreased calcineurin inhibitor levels might improve or prevent renal insufficiency and improve control of rejection. A retrospective chart review was performed on the patients treated with sirolimus who had undergone an orthotopic liver transplant between January 2000 and February 2003. Thirty-eight patients were identified. Mean age was 8.6 yr. Fourteen patients were male and 24 were female. Mean weight was 30.3 kg. The most common indications for starting sirolimus were rejection (42%) and renal impairment (29%). Seventy-three percent of patients begun on sirolimus remain on the medication. Those with renal impairment (11 patients) showed improvement in their creatinine levels from a mean baseline of 1.3 to 0.8 mg/dL. Their calculated creatinine clearance (Schwartz formula) improved from 63.7 to 84.8 mL/min (p = 0.03). Patients started on sirolimus for rejection showed significant improvement in hepatocellular enzymes despite a reduction in the tacrolimus level from 12.2 to 7.5 ng/mL. The mean alanine aminotransferase level improved from 221 to 100 units/L (p = 0.02), and the mean aspartate aminotransferase improved from 121 to 99 units/L (p = 0.59). Addition of sirolimus to a tacrolimus-based regimen with lower target tacrolimus levels improved liver function in patients with rejection. Addition of sirolimus significantly improved renal function as shown by creatinine level and calculated creatinine clearance in those children with renal impairment. The effect of combined immunosuppressant treatment with tacrolimus and sirolimus on long-term renal function needs to be evaluated.
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PMID:Improvement in renal function and rejection control in pediatric liver transplant recipients with the introduction of sirolimus. 1526 63

Rapamune, an inhibitor of the mammalian target of rapamycin, exhibits antiproliferative actions and is increasingly used as adjuvant therapy with calcineurin inhibitors. This study investigated the effect of Rapamune on functional and molecular markers in a rat model of calcineurin inhibitor-induced graft dysfunction. Prograf (6 mg), with or without addition of Rapamune (1 mg), was administered to salt-depleted male rats (n = 6/group). Urinary protein excretion and serum creatinine were measured. Rats were culled at 28 days, and messenger RNA expression of TGF-beta, MMP-2, MMP-9, TIMP-1, and collagen III was evaluated with reverse transcriptase polymerase chain reaction. Serum creatinine increased with Prograf (P = .01), but not Rapamune (P = .69) treatment, compared to controls at 28 days. The combination of Rapamune and Prograf produced a rise in serum creatinine at 7 (P = .007) and 14 (P = .01) days, but this was not observed at later time points. Urinary protein excretion was unaltered by any drug or combination. While confirming a synergistic effect of Rapamune and calcineurin inhibitors on renal function, these results suggest that sole therapy with Prograf produces inhibition of fibrotic gene expression. Rapamune alone has no deleterious effect on gene expression but addition of Rapamune cancels out the beneficial effects of Prograf.
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PMID:Prograf produces a molecular environment favoring antifibrosis, an effect reversed by the addition of rapamune. 1580 77

A highly selected subject group comprising pediatric recipients of liver (n = 36) and small intestine alone (n = 1) or multivisceral graft (n = 2) were converted to sirolimus maintenance therapy for tacrolimus-related side effects (n = 32) or by primary intent (n = 7). Indications were nephrotoxicity (n = 14), primary intent (n = 7), post-transplant lymphoproliferative disorder (n = 6), seizures (n = 4), recurrent acute rejection (n = 2), and cardiomyopathy (n = 1). Thirty subjects (78%) experienced successful conversion, with one subject requiring atorvastatin for hypercholesterolemia and hypertriglyceridemia. Nine subjects (22%) were converted back to tacrolimus for serious adverse events including acute rejection (n = 2), elevated liver function tests (n = 1), severe leucopenia (n = 1), non-compliance (n = 2), recurrent malignancy/death (n = 1), steatohepatitis (n = 1), and thrombocytopenic thrombotic purpura (n = 1). Among subjects with nephrotoxicity, significant benefit was seen only in those subjects with shorter time to rescue after transplantation (n = 8 of 14 subjects). Additional benefits included a significant decrease in mean serum creatinine from pretransplant values for the entire population, and elimination of antihypertensive treatment in all five subjects receiving it prior to conversion. Hemoglobin, serum cholesterol and triglycerides, white cell counts and platelets remained within normal limits for the duration of follow-up (36 month). Conversion from tacrolimus to sirolimus is successful in selected pediatric liver and intestine recipients. Chronic nephrotoxicity may be ameliorated by early conversion. Improvement in renal function and hypertension management, and absence of sirolimus-related adverse events argue for prospective evaluation of regimens in which mTOR inhibitors are used without calcineurin inhibitors in children.
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PMID:Replacing calcineurin inhibitors with mTOR inhibitors in children. 1591 Mar 98

Calcineurin inhibitors (CNI) have played an important role in improving graft survival. However, the balance between preventing immunologic allograft losses and the management of CNI-related nephrotoxicity is still an issue in renal transplantation. There are three major CNI-sparing strategies. CNI MINIMIZATION: The advent of mycophenolate mofetil (MMF) allows cyclosporine (CsA) reduction to ameliorate renal function in patients with chronic renal allograft dysfunction, without increasing acute rejection rates. In combination with mTOR inhibitors, very low CNI levels may be sufficient to prevent acute rejection. However, in this association, CNI nephrotoxicity is magnified by pharmacokinetic interaction. CNI WITHDRAWAL: CNI withdrawal has been attempted in regimens containing MMF or sirolimus (SRL). Introduction of MMF in patients with chronic allograft nephropathy (CAN) followed by CNI withdrawal resulted in stabilization or improvement of renal function and hypertension profile, although there is some risk of acute rejection. In regimes based on SRL, CNI withdrawal is a safety strategy, achieving a sustained improvement of renal function, histology, and graft survival. There is not consensus at all whether MMF should be added or not in patients converted from CNI to mTOR inhibitor. CNI AVOIDANCE: Polyclonal-based regimens with MMF and steroids have shown acceptable acute rejection rates, but high rates of cytomegalovirus (CMV) and opportunistic infections. Conversely, anti-IL-2R in combination with MMF and steroids resulted in 50% incidence of acute rejection, thus suggesting that CNI avoidance is not feasible in a regimen based on MMF. Alternatively, a protocol based on anti-IL-2R induction therapy combined with SRL, MMF, and prednisone has shown an efficient prevention of acute rejection, higher creatinine clearance and lower rate of CAN in comparison with a group treated with CNI. New strategies using costimulation blockade may help in the development of safe CNI-free regimens. In summary, in renal transplantation the new immunosuppressive medications have made feasible old aspirations such as minimization, withdrawal, or even avoidance of CNI.
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PMID:Calcineurin-inhibitor-sparing immunosuppressive protocols. 1638 20

The mTOR inhibitor sirolimus improves renal transplant function compared with the nephrotoxic calcineurin inhibitors. We evaluated retrospectively the adverse events in 119 of 134 patients getting sirolimus which seemed to be caused by sirolimus. Patients were converted to sirolimus because of malignancies (n = 47), a creeping creatinine (n = 33), or hypertension (n = 26). One cohort had started sirolimus from the time of transplantation (n = 28). A rise in serum lipids and a decrease in hemoglobin were seen relatively regularly, while arthralgia, peripheral edema, gastrointestinal complaints, skin disorders, electrolyte disturbances, and infections occurred only occasionally. Interestingly, 31% of patients developed doubling or more proteinuria. Among renal biopsies, 9/13 showed a glomerulopathy which in 6 cases was de novo and in 3 cases, a presumed recurrence of the primary kidney disease. Thus, we think that caution is required, particularly in connection with preexisting glomerular disease.
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PMID:Side effects of sirolimus. 1664 52

Calcineurin inhibitors (CNIs) are associated with important side effects, such as nephrotoxicity, and thus there is an interest in developing CNI-sparing protocols using agents such as the proliferation signal inhibitor/mammalian target of rapamycin inhibitor everolimus. In a 3-month pilot study using an abrupt conversion protocol, ciclosporin (CsA) treatment was stopped after the morning dose and everolimus was started at 3.0 mg/day. Mycophenolic acid (MPA)-based therapy was continued, or prednisolone increased to 10 mg/day until target everolimus trough blood levels (3-8 ng/ml) were achieved. To date, seven patients have been enrolled, with three having completed at least 3 months of follow-up. Overall, conversion was effective and well-tolerated. Patients consistently achieved everolimus trough blood levels >3 ng/ml, and no episodes of acute rejection or proteinuria were reported after 3 months. In patients who completed the study, there were no major changes in the leucocyte or platelet counts during everolimus treatment. Serum creatinine levels were maintained or decreased slightly. One patient experienced a transient increase in serum creatinine during an episode of pneumonia, but levels decreased again after resolution of infection and temporary everolimus dose reduction. Serum cholesterol and triglyceride levels increased, but remained within acceptable limits. One patient receiving enteric-coated mycophenolate sodium 1440 mg/day experienced increasing everolimus trough blood levels and anaemia after conversion, and was therefore likely to have been over-immunosuppressed. Abrupt conversion to everolimus from CsA was effective and well-tolerated in renal transplant recipients. A reduction in MPA dosage at the time of conversion may be necessary to prevent over-immunosuppression.
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PMID:Conversion to everolimus in maintenance patients--current clinical strategies. 1681 53

Calcineurin inhibitors (CNIs) are frequently associated with side effects such as nephrotoxicity and hypertension, so CNI withdrawal from immunosuppressive regimens is desirable in certain cases. The proliferation signal inhibitors/mammalian target of rapamycin inhibitors everolimus and sirolimus may play an important role in achieving CNI withdrawal. Studies on sirolimus have shown that conversion from CNIs is associated with improvements in renal function and hypertension. A case report is presented of a renal transplant recipient who experienced hypertension and recurrent cutaneous neoplasia while receiving a ciclosporin (CsA)-based immunosuppressive regimen. After transplantation, the patient received full-dose CsA and prednisolone. After 7 years, the patient's serum creatinine increased from 1.9 mg/dl to 2.5 mg/dl, and mycophenolate mofetil (MMF, 1000 mg/day) was introduced, enabling the CsA dose to be reduced to 100 mg b.i.d. The patient also required resection of five cutaneous neoplastic lesions; this led to the decision to stop CsA and start treatment with everolimus 1.5 mg/day, which was increased to 3.0 mg/day to achieve target trough blood levels of 3 ng/ml. To avoid over-immunosuppression, the MMF dose was reduced to 500 mg/day. After conversion, the patient experienced a substantial improvement in blood pressure, from 175/85 mmHg to 155/70 mmHg. Serum creatinine levels decreased to 1.6 mg/dl, and there has been no recurrence of cutaneous neoplasia in 9 months of follow-up. Therefore, conversion to everolimus from CsA in a renal transplant recipient led to improvements in blood pressure and resolution of recurrent cutaneous neoplasia, with no evidence of rejection or changes in renal function.
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PMID:Conversion to everolimus in a patient with arterial hypertension and recurrent cutaneous neoplasia--a case report. 1681 57

New immunosuppressive agents are being actively researched to avoid complications of chronic allograft nephropathy (CAN), calcineurin inhibitor (CNI) nephrotoxicity, and posttransplantation cancer. The family of mTOR inhibitors offers a unique immunosuppressive opportunity to avoid CNI toxicity and reduce the incidence of malignancy. Nevertheless, increasing data have demonstrated that sirolimus (SRL), the first mTOR introduced in the treatment of solid organ transplant recipients, induces proteinuria, an adverse event that could produce deterioration of long-term renal function. In this short-term study of patients followed for 1 to 16 months, we examined changes in renal function and proteinuria among renal transplant recipients converted from a CNI-based regimen to an everolimus (EVL)-based one, a recently introduced mTOR inhibitor. Our data showed that renal function can be optimized after conversion to EVL by up to 42% in recipients showing CAN grade 1 or 2, or CNI nephrotoxicity. Importantly, patients who improved their creatinine clearance did not show increased proteinuria measured in a voided specimen as the ratio of urinary protein and creatinine concentration (P/C). These results, if confirmed with long-term follow-up and a larger number of patients, would allow us to consider EVL as a promising agent for maintenance immunosuppressive regimens in kidney transplantation.
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PMID:Conversion from a calcineurin inhibitor-based immunosuppressive regimen to everolimus in renal transplant recipients: effect on renal function and proteinuria. 1744 51

Mammalian Target-of-Rapamycin inhibitors (mTOR inhibitors) can be used to replace the calcineurin inhibitors (CNIs) to prevent progression in chronic kidney disease (CKD) following organ transplantation. Discontinuation of tacrolimus in 136 recipients of kidney transplants with progressive renal dysfunction significantly decreased the rate of loss of estimated glomerular filtration rate (eGFR, mL/min/1.73 m(2)) (pre-intervention vs. post-intervention slopes, -0.013 vs. -0.002, p < 0.0001). Discontinuation of tacrolimus was associated with a sustained and significant improvement in graft function (pre-eGFR vs. post-eGFR; 26.0 +/- 1.1 vs. 47.4 +/- 2.1, p < 0.0001) in 74% of patients. This intervention was ineffective if the mean and (median) values of creatinine (mg/dL) and eGFR were 3.8 +/- 0.2 (3.4) and 18.4 +/- 1.9 (22.4), respectively, at the time of conversion therapy. During the follow-up (range, 1.5-34.6, months), a total of 13 patients had their first acute rejection following the conversion therapy, an annual incidence of less than 10% and none of these episodes resulted in graft loss. The salutary effects of sirolimus therapy following discontinuation of tacrolimus in patients with moderate to severe graft dysfunction due to allograft nephropathy even in high-risk patients improves kidney function and prevents acute rejection.
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PMID:Early withdrawal of calcineurin inhibitors and rescue immunosuppression with sirolimus-based therapy in renal transplant recipients with moderate to severe renal dysfunction. 1751 82

The inhibition of mTOR is a target for anticancer drugs in posttransplant malignancies. The influence of conversion to sirolimus after malignancy diagnosis was investigated on patient and renal allograft survivals. The 20 renal allograft recipients (4 women, 16 men) of ages 26 to 73 years (mean, 59 years) developed malignancies within 6 to 172 months (mean, 53 months) after transplantation. Three patients developed posttransplant lymphoproliferative disease (PTLD); four, Kaposi sarcoma, three, lung cancer; two, malignant melanoma; two, breast cancer; two, renal cell carcinoma; one, Merkel cell carcinoma; one, cutaneous T-cell lymphoma; one, larynx cancer; and one, gingival cancer. After tumor diagnosis, calcineurin inhibitors, azathioprine, or mycophenolate mofetil (MMF) were discontinued abruptly and sirolimus introduced (2 mg/d; target trough level, 4.0 to 8.0 ng/mL). Prednisone was maintained. The observation time of sirolimus therapy was 4 to 48 months (mean, 14 months). Two patients with PTLD (large B-cell lymphoma) and four with Kaposi sarcoma had full regressions. Eleven patients (larynx cancer, melanoma, breast cancer, T-cell lymphoma, renal cell carcinoma, Merkel cell carcinoma, and skin lymphoma) in addition to sirolimus therapy, underwent oncologic treatment, namely, surgery and/or chemotherapy. Six patients died from disseminated malignancy 4 to 9 months after conversion. One patient with T-cell lymphoma lost his graft; in the remaining patients, serum creatinine level was stable. In conclusion, Conversion to sirolimus resulted in regression of large B-cell lymphoma and Kaposi sarcoma. In patients with advanced or disseminated malignancy, the tumors progressed. Graft function was preserved after conversion to sirolimus.
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PMID:Anticancer effect of sirolimus in renal allograft recipients with de novo malignancies. 1802 73


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