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)

Over the last decade, there has been a decrease in acute graft rejection rates following renal transplantation; however, this has not corresponded with an improvement in long-term outcomes of transplantation. One of the major causes of long-term morbidity and mortality in renal transplant recipients is cardiovascular disease. Immunosuppressive regimens, especially those including steroids and calcineurin inhibitors, have a negative role in the induction of cardiovascular risk factors. The proliferation signal inhibitors (PSIs)/mammalian target of rapamycin (mTOR) inhibitors sirolimus and everolimus have shown considerable promise in reducing acute rejection in renal transplant recipients. Although PSIs are associated with an increase in hyperlipidaemia (hypercholesterolaemia and hypertriglyceridaemia), which is a major risk factor for atherosclerosis and associated cardiovascular disease, recent studies with sirolimus have demonstrated protection from atheroma progression in hyperlipidaemic apolipoprotein E-deficient mice. Here, we summarize the results of pre-clinical and clinical studies with sirolimus and everolimus, with particular emphasis on the beneficial and adverse effects that these drugs exert on the cardiovascular system, and the underlying molecular mechanisms.
Nephrol Dial Transplant 2006 Jul
PMID:Potential role of proliferation signal inhibitors on atherosclerosis in renal transplant patients. 1681 51

Everolimus is a proliferation signal inhibitor (PSI)/mammalian target of rapamycin inhibitor that is structurally similar to sirolimus, but with a number of important pharmacokinetic differences, including a shorter half-life and time to steady state. In clinical trials, the efficacy of everolimus 1.5 mg/day and 3.0 mg/day combined with ciclosporin (CsA) and steroids in de novo renal transplant recipients is similar to that of mycophenolate mofetil, with one study showing a significantly lower risk of antibody-treated acute rejection with everolimus. When combined with reduced-dose CsA, everolimus is associated with improved renal function compared with full-dose CsA, with no decrease in efficacy. Thus, everolimus may play an important role in calcineurin inhibitor (CNI)-sparing regimens for renal transplant recipients. Studies with sirolimus have shown that CNI withdrawal is associated with a significant improvement in renal function, although there may be an increase in the risk of acute rejection. however, patient and graft survival are not adversely affected by CNI withdrawal. Notably, proteinuria <800 mg/day before conversion is a strong predictor of successful response to sirolimus treatment, and hypertensive therapy and serum lactate dehydrogenase levels may also predict response. Adverse events commonly associated with the PSIs include dyslipidaemia, proteinuria and anaemia, although these can usually be managed without difficulty. Data are also available to suggest that the PSIs are associated with a lower risk of malignancy than other immunosuppressive agents. In conclusion, everolimus may permit reduced exposure to CNIs in renal transplant recipients, with the potential to improve tolerability and renal function.
Nephrol Dial Transplant 2006 Jul
PMID:Everolimus in clinical practice--renal transplantation. 1681 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.
Nephrol Dial Transplant 2006 Jul
PMID:Conversion to everolimus in maintenance patients--current clinical strategies. 1681 53

The calcineurin inhibitors (CNIs) ciclosporin (CsA) and tacrolimus are currently an important part of immunosuppressive regimens, but are associated with increased cardiovascular risk factors, including hyperlipidaemia, hypertension and diabetes mellitus. Conversion from CNI-based regimens to proliferation signal inhibitors or mammalian target of rapamycin inhibitors, such as everolimus and sirolimus, has been associated with an improvement in cardiovascular risk. This case study describes a 59-year-old renal transplant recipient who presented with angina pectoris while receiving immunosuppression with CsA, azathioprine and steroids. The patient developed angina pectoris 5 years after receiving a cadaveric renal transplant. At the time, the patient was obese, with hypertension controlled with diuretics and calcium channel blockers, and hyperlipidaemia controlled with statins. A scintigram revealed plurisegmental myocardial ischaemia, and a coronary angiogram showed the presence of occlusions in the left anterior descending artery and circumflex coronary artery. The patient also had 70% stenosis of the right coronary artery, which was corrected by angioplastic percutaneous intervention. The patient was converted from azathioprine to sirolimus 2 mg/day (trough blood level, 6-10 ng/ml), while the CsA dose was tapered and withdrawn. The angina pectoris subsequently resolved, no progression of coronary artery disease (CAD) has been observed during follow-up and stable renal function has been maintained throughout. Conversion to an immunosuppressive regimen of sirolimus with CsA withdrawal, along with angioplastic percutaneous correction of right coronary artery stenosis, therefore led to the complete resolution of angina pectoris and no progression of the CAD was noticed in this obese renal transplant patient with drug-controlled hypertension and hyperlipidaemia.
Nephrol Dial Transplant 2006 Jul
PMID:Conversion to a proliferation signal inhibitor in a patient with coronary artery disease--a case report. 1681 56

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.
Nephrol Dial Transplant 2006 Jul
PMID:Conversion to everolimus in a patient with arterial hypertension and recurrent cutaneous neoplasia--a case report. 1681 57

The proliferation signal inhibitors [PSIs; mammalian target of rapamycin (mTOR) inhibitors] are widely used for immunosuppression in transplant recipients. Alongside their immunosuppressive properties, PSIs also have substantial anti-neoplastic activity, as a result of their inhibition of cellular signalling pathways involved in critical functions such as cell division, T-cell activation, invasion and growth factor production. In vitro and in vivo studies have shown that PSIs can prevent the growth of experimentally transformed cells and tumour-derived cell lines, and can also increase the sensitivity of cells to apoptosis-inducing agents. The mechanisms of anti-tumour activities of PSIs identified in pre-clinical studies include up-regulation of adhesion molecules with reversion to less invasive phenotypes, and inhibition of angiogenesis resulting from both decreased vascular endothelial growth factor production and decreased endothelial sensitivity to such growth factors. In clinical trials of PSIs in transplant recipients, results show that the incidence of malignancies is substantially lower in patients receiving PSIs than in those receiving calcineurin inhibitor (CNI)-based immunosuppression, with significantly longer times to the development of malignancy. This protective effect of the PSIs is also present in patients receiving combination therapy with a CNI and a PSI. There is also evidence to suggest a role for PSIs in the management of post-transplantation malignancy, with reports of complete resolution of primary and metastatic tumours after conversion from a CNI to a PSI. These beneficial effects have led to the investigation of everolimus and an analogue of sirolimus as a treatment for patients with advanced solid tumours.
Nephrol Dial Transplant 2007 May
PMID:The role of proliferation signal inhibitors in post-transplant malignancies. 1736 Jul 68

Increasing success in renal transplantation and longer patient survival has meant that post-transplant malignancies are having an increasing impact on long-term graft and patient survival. Choice of the immunosuppressive agents provides one of the controllable risk factors for the development of malignancies in this population. Calcineurin inhibitors (CNIs) are associated with an increased incidence of cancers, whereas the proliferation signal inhibitors (PSIs), everolimus and sirolimus have demonstrated anti-oncogenic effects in pre-clinical models and are currently being investigated as anti-cancer agents in clinical trials. There is increasing evidence demonstrating a lower incidence of post-transplant malignancies in renal transplant recipients receiving PSI-based immunosuppression compared with those receiving CNIs. Conversion from CNIs to PSIs has been shown to lead to the regression of Kaposi's sarcoma in renal transplant recipients and is now part of accepted standard care for this tumour in this setting. The anti-cancer properties of PSI-based regimens have the potential to combine the dual benefits of immunosuppression without the use of CNIs and the direct anti-oncogenic effects through their inhibition of the mammalian target of rapamycin (mTOR) signalling pathway. In the absence of formal clinical trial evidence on the best way to use PSIs in this setting, a workshop was held to provide practical guidance on immunosuppressive strategies in the context of malignancy, given the current state of knowledge.
Nephrol Dial Transplant 2007 May
PMID:Use of proliferation signal inhibitors in the management of post-transplant malignancies--clinical guidance. 1745 17

Acute rejection episodes are now as low as 5-20% in the first year after renal transplantation; however, graft half-life has remained almost unchanged in the last decade. This statistic is mainly attributable to the side effects of immunosuppression, with loss of allografts due to the chronic allograft nephropathy that is a consequence of calcineurin inhibitor toxicity or hypertension. Patient death due to cardiovascular events, infections and malignancy also contribute to allograft loss. The introduction of the inhibitors of the mammalian target of rapamycin sirolimus and everolimus in renal transplantation has increased the repertoire of immunosuppressive protocols substantially. They have a different mode of action and a different side effect profile (i.e. lower nephrotoxicity, less hypertension and less neoplastic potential) than the calcineurin inhibitors. The inhibitors of the mammalian target of rapamycin therefore provide an especially promising alternative for the maintenance immunosuppression after renal transplantation. This overview provides a summary of the current literature on inhibitors of the mammalian target of rapamycin, with a special focus on sirolimus.
Nephrol Dial Transplant 2007 Sep
PMID:Sirolimus in renal transplantation. 1789 Feb 66

Inhibitors of mTOR (mammalian target of rapamycin) are immunosuppressants with less nephrotoxic potential than calcineurin inhibitors and antiproliferative effects, which are advantageous in the case of malignancy. However, a series of adverse events has been reported with the first-generation mTOR inhibitor sirolimus that includes hypersensitivity-like interstitial pneumonitis. To our knowledge, only one case of a pneumonitis associated with everolimus in a heart transplant patient has been reported, and it was related to elevated trough blood levels. We report herein the first case of a kidney graft recipient who developed everolimus-associated pneumonitis with normal trough blood levels that was completely reversed after drug withdrawal.
Nephrol Dial Transplant 2008 Oct
PMID:Severe everolimus-associated pneumonitis in a renal transplant recipient. 1865 77

The most serious complication of peritoneal dialysis is encapsulating peritoneal sclerosis (EPS). The prolonged inflammatory stimuli, fibrogenic cytokine overexpression, and angiogenesis that underlie EPS ultimately result in increased production of fibrous tissue, encapsulating the bowel loops. In recent years, inhibitors of mammalian target of rapamycin (mTOR) as an alternative agent for calcineurin inhibitor toxicity have been widely used in organ transplantation. These agents have also been used since the 1990s in endovascular medicine for drug-eluting stents because of antiproliferative effects on vascular smooth muscle cells and potent anti-inflammatory properties by direct action on human immune cells. Because of the shared characteristics of EPS and other fibrotic processes, we hypothesized that everolimus, an mTOR inhibitor can reverse the process responsible for the eventual development of EPS. We allocated 32 non-uremic albino Wistar rats to 4 groups: control group, 2 mL isotonic saline injected intraperitoneally (IP) daily for 3 weeks; CG group, 2 mL/200 g (0.1%) chlorhexidine gluconate (CG) injected IP daily and ethanol (15%) dissolved in saline, for 3 weeks; resting group, CG (weeks 0 - 3), plus peritoneal rest (weeks 3 - 6); and Evo-R, CG (weeks 0 - 3), plus 0.3 mg/L everolimus in drinking water (weeks 3 - 6). At the end of the study, we performed a 1-hour peritoneal equilibration test with 25 mL 3.86% PD solution, and examined the dialysate-to-plasma ratio of urea (D/P urea), dialysate white blood cell count, ultrafiltration (UF) volume, and morphologic change in the parietal peritoneum. Exposure to CG for 3 weeks resulted in alterations in peritoneal transport (increased D/P urea, decreased UF volume, p < 0.05) and morphology (increased inflammation, neovascularization, fibrosis, and peritoneal thickness, p < 0.05). Peritoneal rest has some beneficial effect only on UF failure and dialysate cell count (p < 0.05). However; everolimus was more effective than peritoneal rest with regard to vascularity and peritoneal thickness (p < 0.05). Everolimus has beneficial effects on UF failure, inflammation, and fibrosis. Everolimus may have therapeutic value in the management of EPS.
Adv Perit Dial 2008
PMID:Effects of everolimus as an antiproliferative agent on regression of encapsulating peritoneal sclerosis in a rat model. 1898 12


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