Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.16 (calcineurin)
17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

While bronchiolitis obliterans organizing pneumonia (BOOP) has been associated with the use of sirolimus (SIR), the incidence in a consecutive group of patients given SIR to replace a calcineurin-inhibitor (CI) is unknown. Twenty-nine consecutive cardiac transplant recipients were switched from a CI to SIR to ameliorate CI-associated nephropathy or coronary graft atherosclerosis. Seven patients (24%) developed BOOP. The clinical characteristics and biopsy results of these patients are presented. The clinical course and response to withdrawal of SIR in all and steroids in four of seven patients suggested the diagnosis of BOOP. Chest X-rays and CT scans showed typical findings of BOOP in all seven patients. Infection was excluded in all patients. Biopsy results were characteristic of BOOP in six of seven patients. Six patients recovered and one died. BOOP is a common and potentially serious adverse event in cardiac transplant patients switched from a CI to SIR, especially when SIR is started late post-transplantation.
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PMID:BOOP is common in cardiac transplant recipients switched from a calcineurin inhibitor to sirolimus. 1588 46

The time to failure of a renal allograft is determined by the initial function achieved after transplantation, the number and severity of insults to the graft, and a number of tissue characteristics. The insults a graft usually encounters include ischaemia/reperfusion injury, acute rejection episodes, drug-related nephrotoxicity, hypertension and hyperlipidaemia. Important tissue characteristics include susceptibility to injury and the ability of the tissue to repair damage. Elderly transplant recipients are considered poor immune responders but if a single acute rejection episode occurs this is more likely to significantly shorten graft and patient survival in this age group. Two issues have been identified with the use of old (>50 years of age) donor kidneys. First, compared with kidneys from younger donors, they have an increased incidence of acute interstitial rejection. Secondly, once a rejection episode occurs, the ability to mount a tissue repair process seems impaired. An explanation for the increased loss of grafts from old donors that have experienced acute rejection episodes is that such kidneys have fewer nephrons that function adequately and that the cumulated effect of damage results in an earlier demise of the graft compared with younger donor kidneys. Alternatively, graft parenchymal cells may undergo premature senescence or aging as a result of multiple injuries and repair. If progressive loss of renal mass or senescence is the mechanism responsible for increased graft loss, then it is expected that grafts from older donors will show a progressive decrease in function over time and that the rate of decline of function will correlate with donor age. We have suggested that increased graft loss of older donor kidneys results from increased incidence of acute rejection episodes in the early post-transplantation months together with a partly impaired ability to repair the tissue. Drug pharmacokinetic parameters are generally little influenced by age. However, the degree to which drugs suppress the immune system, and the extent to which kidneys from older donors are susceptible to the nephrotoxic effects of certain drugs, are unpredictable. There appears to be a more delicate balance between adequate immunosuppression and excess nonimmune toxicity in patients receiving older kidneys. Outcome parameters in elderly renal transplant recipients are currently dominated by increased death from infectious disease and drug-related (cardiovascular) causes. Increased susceptibility to nephrotoxic drugs, and to calcineurin inhibitors in particular, may be related to the increased risk of allograft failure experienced by the elderly as a surrogate for chronic allograft nephropathy.
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PMID:The impact of age on rejection in kidney transplantation. 1590 55

Mycophenolate mofetil (MMF) introduction with concurrent reduction in calcineurin inhibitors has been shown to be beneficial in chronic allograft nephropathy (CAN) in adults. MMF was introduced to 19 children with CAN 26.3+/-5.8 (range 3.1-82.6) months after transplantation. Patients were followed up for a mean of 13.2+/-2.9 (range 1.2-51.1) months. The mean initial MMF dose was 660+/-56 mg/m2 per day, increased to 1,042+/-73 mg/m2 per day a year later. Cyclosporin was reduced from 138+/-10 mg/m2 per day at MMF introduction, to 116+/-15 mg/m2 per day at 6 months and 107+/-24 mg/m2 per day at 1 year. Six months prior to MMF introduction GFR deteriorated by -32.7+/-7.3 ml/min per 1.73 m2 per year. Six months after the introduction of MMF, GFR improved by +26.2+/-7.1 ml/min per 1.73 m2 per year (P <0.001). The introduction of MMF significantly reduced both the graft rejection rate (P=0.01) and systolic blood pressure (P=0.01), without a significant change in antihypertensive treatment. Haematological parameters did not significantly differ before and after MMF introduction. The introduction of MMF in paediatric renal transplant recipients with CAN may cause a significant improvement in GFR in both the short-term and the long-term and may well have a beneficial effect on systolic blood pressure. MMF has the potential to enable CNI-sparing protocols to be adopted.
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PMID:Chronic allograft nephropathy and mycophenolate mofetil introduction in paediatric renal recipients. 1613 52

Mycophenolate mofetil (MMF), a prodrug of mycophenolic acid (MPA), an inhibitor of inosine-5'-monophosphate dehydrogenase, has several immunosuppressant actions. MPA depletes guanosine and deoxyguanosine nucleotides preferentially in T and B lymphocytes, inhibiting proliferation and suppressing cell-mediated immune responses and antibody formation, major factors in acute and chronic rejection. MPA also can induce T-lymphocyte apoptosis. MPA suppresses dendritic cell maturation and can induce human monocyte-macrophage cell line differentiation, decreasing the expression of interleukin (IL)-1 and enhancing expression of the IL-1 receptor antagonist. In addition, MPA inhibits adhesion molecule glycosylation and expression and lymphocyte and monocyte recruitment. Activated macrophages produce nitric oxide (NO) and superoxide, which combine to generate tissue-damaging peroxynitrite. MPA depletes tetrahydrobiopterin and decreases NO production by inducible NO synthase without affecting constitutive NO synthase activity. By these mechanisms, MMF exerts anti-inflammatory activity, which could attenuate both acute and chronic rejection. Unlike calcineurin inhibitors, MMF is nonnephrotoxic and does not induce transforming growth factor-beta production, which is fibrogenic. MMF inhibits arterial smooth muscle cell proliferation, a contributor to graft proliferative arteriopathy, and does not increase blood pressure, cholesterol, or triglyceride levels. By decreasing high-density lipoprotein oxidation and macrophage recruitment, MMF also may delay onset/progression of graft atherosclerosis. Thus, MMF may prevent chronic rejection by several mechanisms. MMF activity is synergistic with that of other agents such as valganciclovir for treating cytomegalovirus infection. MMF also has synergistic activity with angiotensin-converting enzyme inhibitors or angiotensin II receptor antagonists in the treatment of some nephropathies in experimental animals. This combination may prevent progression toward end-stage renal disease in humans with chronic allograft, lupus, and diabetic nephropathies.
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PMID:Mechanisms of action of mycophenolate mofetil in preventing acute and chronic allograft rejection. 1625 60

Interstitial fibrosis is the main characteristic of chronic allograft nephropathy and long-term graft failure. Cyclosporin (CsA) is thought to be more fibrogenic than tacrolimus. In a prospective, randomized, multicenter trial using a calcineurin-sparing regimen, renal interstitial volume was compared in CsA- and tacrolimus-treated renal transplant recipients by image analysis of Sirius red (SR)-stained cortical areas in protocol biopsies obtained at 6 mo (n = 94) and 12 mo (n = 97) after transplantation. Immunosuppression consisted of CsA or tacrolimus, CD25 mAb, mycophenolate mofetil, and prednisolone. CsA therapy increased the 6-mo risk for subclinical rejection. The prevalence of subclinical rejection was 38.8% in the CsA-treated and 15.2% in the tacrolimus-treated patient group (P = 0.012). Strikingly, no difference in the degree of interstitial SR-stained area was detectable between the two treatment groups. In particular, previous subclinical rejection episodes did not influence the degree of interstitial volume. Also, no difference in GFR occurred at 1 yr, when the mean GFR mounted 63 ml/min. No significant differences in the degree of interstitial SR-stained area could be observed at 6 and 12 mo between CsA- and tacrolimus-treated renal transplant recipients. Although CsA-treated patients developed significantly more subclinical rejections at 6 mo, this did not influence the degree of SR staining or the change in renal function at 1 yr.
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PMID:No difference in degree of interstitial Sirius red-stained area in serial biopsies from area under concentration-over-time curves-guided cyclosporine versus tacrolimus-treated renal transplant recipients at one year. 1630 68

Renal function early after transplantation is associated with a large number of risk factors, including donor age and acute rejection. During the 1990s, donor age increased and the incidence of acute rejection decreased. Renal function between the third and sixth month improved slightly, while renal function deterioration between the third or sixth month and the 12th month improved significantly. This modification coincides with the introduction of mycophenolate mofetil and tacrolimus. The tendency for sustained renal improvement early after transplantation became more evident after the introduction of anti-calcineurin-free regimens. Studies of protocol biopsies have shown that there is an increase of glomerular volume after transplantation and that a larger glomerular volume at 4 months is associated with a better glomerular filtration rate. This adaptation mechanism is impaired in patients with chronic allograft nephropathy or in patients with high cyclosporin levels. Taken together, these data suggest that the steady improvement of renal allograft function may be partly explained by a better glomerular adaptation after transplantation because of the avoidance of the vasoconstrictive effect of anti-calcineurinic agents, and a significant decrease in the prevalence of chronic allograft nephropathy early after transplantation.
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PMID:Risk factors associated with the deterioration of renal function after kidney transplantation. 1633 63

Renal transplantation is the best therapeutic option for patients with end-stage renal disease. Although short-term results are excellent, long-term graft survival has not improved substantially in recent times. Chronic allograft nephropathy (CAN) and death with a functioning graft are the most important causes of graft loss. Recent evidence shows that nephrotoxicity of calcineurin inhibitors contributes to CAN, and the introduction of non-nephrotoxic drugs such as mycophenolate mofetil (MMF) and mammalian target of rapamycin inhibitors may provide new immunosuppressive strategies to improve long-term results after renal transplantation. MMF decreases the risk of developing chronic allograft failure and is useful for treating established CAN, because it has a beneficial effect on allograft fibrosis. Treatment with sirolimus (SRL), a basic immunosuppressive drug given in association with MMF, may offer better renal function, decrease the prevalence of CAN, and downregulate expression of genes responsible for the progression of CAN than treatment with cyclosporine A (CsA). SRL also permits an early elimination of CsA from SRL-CsA-steroid regimens and shows better renal function and improved renal histology without risk of rejection. Notably, this approach improves graft survival at 4 years. Further multicenter studies are needed to determine whether both approaches produce similar results by comparing immunosuppression caused by SRL-based and tacrolimus (TAC)-based treatments. Because TAC is the most commonly used anticalcineurin drug, it is important to compare the effects of steroid-TAC-SRL treatment with and without elimination of TAC. Finally, although caution is needed, the use of non-nephrotoxic immunosuppressive treatment may change the natural history of CAN.
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PMID:Immunosuppressive treatment and progression of histologic lesions in kidney allografts. 1633 65

Sirolimus (Rapamycin, Wyeth Pharmaceuticals Australia Pty Ltd, Baulkham Hills, NSW, Australia) (SRL) has received increasing attention as an immunosuppressant in renal and other solid organ transplantation. Sirolimus is the first marketed agent in a new class of drugs with a novel mechanism of action. Sirolimus binds, like tacrolimus, to a member of the FK binding protein (FKBP) family. The SRL/FKBP complex binds to the protein kinase mTOR. Binding to mTOR blocks activation of signal transduction pathways causing arrest of the cell cycle in the G1 phase. It is now known that mTOR is a central regulator of cell growth and proliferation. The immunosuppressive properties of SRL are due primarily to blockade of interleukin-2 (IL-2)-induced proliferation of T cells. There is still much to be learnt about how best to use the drug. The key advantage over the current choice of immunosuppressive agents is the ability to preserve renal function and pathology while producing excellent rejection-free, graft survival rates. Thus, SRL may find its pivotal role as a calcineurin inhibitors replacement in patients whose grafts are affected by chronic allograft nephropathy. A second major driver for use may prove to be the impact of SRL on cancer incidence and prognosis. Studies still need to be performed to evaluate the best timing for commencement of SRL and the optimal dosage to minimize side-effects.
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PMID:Sirolimus: its role in nephrology. 1635 46

Endothelial dysfunction and damage are systemic processes that are recognised to play a central role in the pathogenesis of hypertension and atherosclerotic cardiovascular disease. Renal failure is associated with impaired endothelium dependent vasodilatation that is partly a consequence of increased circulating levels of asymmetric dimethyl arginine. Endothelial dysfunction persists, although it is improved, after renal transplantation. Statins appear to improve endothelial dysfunction, as does withdrawal of calcineurin inhibitors, although there is no evidence that these strategies improve patient or graft survival. The situation in transplant recipients is complicated by the fact that endothelial dysfunction (within the graft vasculature) may be a separate process contributing to chronic allograft nephropathy and to circulating levels of endothelial cells and their components, thus limiting the utility of circulating markers of endothelial damage in this population.
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PMID:Endothelial dysfunction in renal transplant recipients. 1638 45

Conversion from calcineurin inhibitors (CNI) to sirolimus (SRL) has become an option in patients with chronic allograft nephropathy or other conditions. However, in some cases an increase of proteinuria has been reported after such therapeutic intervention. The aim of this study was to characterize the clinical course of this so far unexplained proteinuria after conversion. We performed a retrospective analysis evaluating 94 renal transplant patients from various Spanish centers. Proteinuria (629 determinations) and clinical developments were analyzed between 6 months before and 6 months after conversion. Patients were divided into three groups according to mean proteinuria before conversion (group A: <300 mg/d; group B: 300 to 2000 mg/d; and group C: >2 g/d). The mean proteinuria level was 1.69 g/24 h (n = 312 determinations) before and 2.36 g/24 h after conversion (n = 317 determinations; P = .006), which corresponds to an overall increase of 25% (1.55 to 1.69 g/24 h considering only determinations of 1 month before and 1 month after conversion; P = NS). We could not detect any clear correlation between proteinuria and serum creatinine nor between changes of proteinuria and changes of serum creatinine. A variance analysis for repeated measures showed an increase in proteinuria compared to the preconversion values (P = .003), and when the three groups of preconversion proteinuria were evaluated separately it could be observed that this change in the evolution of proteinuria was almost completely dependent of an increase in the group C (preconversion proteinuria greater than 2 g/d; P = .03), whereas in the other two groups changes were almost irrelevant. Finally, the switch to SRL in renal transplant recipients is followed by an increase in the level of proteinuria predominantly dependent of an increase in patients with high levels of preconversion proteinuria, whereas it seems to be irrelevant in patients without or with light or moderate proteinuria. These results suggest that this might not be a direct effect of SRL.
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PMID:Evolution of proteinuria after conversion from calcineurin inhibitors (CNI) to sirolimus (SRL) in renal transplant patients: a multicenter study. 1638 55


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