Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transient global or forebrain ischemia leads to severe brain damage following delayed neuronal cell death. We previously reported that cyclosporin A (CsA) provides near total suppression of brain damage in rat forebrain ischemia when allowed to pass the blood brain barrier, whereas Tacrolimus (FK506) is considerably less effective. We demonstrate herein that when administered prior to ischemic insult, both immunosuppressants equally block calcineurin, a type 2B Ser/Thr phosphatase, and efficiently inhibit dephosphorylation of pro-apoptotic protein Bad. CsA demonstrates more potent anti-ischemic effects than FK506, partially attributable to amelioration of mitochondrial damage as assayed in vivo and in vitro. These results suggest that pathways including calcineurin and cyclophilins, particularly mitochondrial cyclophilin D, play pivotal roles in ischemic brain damage. Since previous results have shown that CsA is efficacious also when administered after focal ischemia, the present findings give hints to clinical applications for new drugs for the treatment of ischemic damage in the brain as well as in the heart and liver.
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PMID:Differential neuroprotection by cyclosporin A and FK506 following ischemia corresponds with differing abilities to inhibit calcineurin and the mitochondrial permeability transition. 1227 Jun 85

Tacrolimus (FK506), a potent immunosuppressive drug, is effective in attenuating brain infarction after cerebral ischemia. However, there has been no report characterizing the neuroprotective action and therapeutic time window of tacrolimus systematically using different types of stroke models and extended observation periods. Therefore, we evaluated the neuroprotective effect of tacrolimus in three different animal models of cerebral ischemia: transient and permanent focal ischemia in rats and transient global ischemia in gerbils. Tacrolimus at doses higher than 0.1 mg/kg (i.v.) produced a statistically significant reduction in ischemic brain damage following permanent and transient focal ischemia in rats when administered immediately after the onset of ischemia. Tacrolimus (1 mg/kg, i.v.) demonstrated similar neuroprotective activity even after delayed administration (2 h after permanent or 1 h after transient focal ischemia). The neuroprotective effect of tacrolimus was still present 2 weeks after transient focal ischemia and 1 week after permanent focal ischemia. After transient global ischemia in gerbils, tacrolimus (1 mg/kg, i.v.) given immediately after reperfusion also produced long-lasting neuroprotective effects with a protective time-window of 1-2 h. Taken together, the results clearly indicate that tacrolimus exerts potent, long-term neuroprotective effects with a favorable therapeutic time-window, regardless of the model of cerebral ischemia. These results strengthen the notion that tacrolimus might be of clinical value for the treatment of acute stroke.
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PMID:Neuroprotective action of tacrolimus (FK506) in focal and global cerebral ischemia in rodents: dose dependency, therapeutic time window and long-term efficacy. 1259 Nov 30

Renal transplant is the treatment of choice for the patient with end stage renal disease. Spain is the country with the highest donation rate (33 ppm). However, at present this figure is stabilized. The development of non-beating heart programmes, living-donor nephrectomy (specially laparoscopic nephrectomy) programmes, and may be xenotransplantation in a non-immediate future could increase the transplantation activity. The knowledge of preservation mechanisms, specially with the use of perfusion machines allows to rescue for transplantation kidneys with a long warm-ischemia time. Furthermore, these machines are useful for analyzing viability markers. The new immunosuppressive drugs: Tacrolimus, Mycophenolate-Mophetil, Rapamycin and monoclonal antibodies against alpha chain of the interleukine-2 receptor (Basoliximab and Dazcizumab) have reduced the incidence of acute rejection in the immediate renal transplant period. However, its effect in the long-term follow-up period is still a matter of controversy. The incidence of tumour in the renal transplant recipient is increased, specially those of lymphoma, skin cancer and Kaposi sarcoma. Periodical exams for detecting the development of tumours are mandatory in this population. Finally, xenotransplantation is an attractive alternative, although immunological, infective and ethical barriers should previously be resolved.
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PMID:[Present and future of kidney transplantation]. 1264 71

The aim of this study was to demonstrate that tacrolimus (FK506) has a hepatoprotective effect by reducing ischemia-reperfusion-induced apoptosis and necrosis, both of which lead to post-surgical liver dysfunction. An ischemia-reperfusion model and primary cultured rat hepatocytes subjected to hypoxic and reoxygenation phases, mimicking the surgical process, were used. c-Jun N-terminal kinase 1/stress-activated protein kinase 1 (JNK1/SAPK1) activation leads to caspase 3 activation, a trigger of apoptosis. The activation status of JNK1/SAPK1 was evaluated by immunoprecipitation or Western-blotting experiments. Apoptosis was assessed by measuring caspase activation and by TUNEL (terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate-biotin nick-end labeling) reaction. Necrosis was assessed histologically. Tacrolimus improved the survival rate of rats subjected to ischemia-reperfusion. After FK506 pretreatment, the liver necrosis rate was reduced, and ischemia-reperfusion-induced JNK1/SAPK1 activation and apoptosis were significantly decreased. In hypoxia-reoxygenation-subjected hepatocytes, tacrolimus reduced JNK1/SAPK1 and caspase 3 activation. In the liver, tacrolimus prevented ischemia-reperfusion-induced apoptosis and necrosis.
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PMID:Rat liver ischemia-reperfusion-induced apoptosis and necrosis are decreased by FK506 pretreatment. 1289 36

Cyclosporin A (CsA) and FK506 (Tacrolimus) are short polypeptides which block the activation of lymphocytes and other immune system cells. Immunosuppressants exert neuroprotective and neurotrophic action in traumatic brain injury, sciatic nerve injury, focal and global ischemia in animals. Their neuroprotective actions are not understood and many hypotheses have been formed to explain such effects. We discuss a role of drug target--calcineurin in neuroprotective action of immunosuppressants. Protein dephosphorylation by calcineurin plays an important role in neuronal signal transduction due to its ability to regulate the activity of ion channels, glutamate release, and synaptic plasticity. In vitro FK506 protects cortex neurons from NMDA-induced death, augments NOS phosphorylation inhibiting its activity and NO synthesis. However, in vivo experiments demonstrated that FK506 in neuroprotective doses did not block excitotoxic cell death nor did it alter NO production during ischemia/reperfusion. Tissue damage in ischemia is the result of a complex pathophysiological cascade, which comprises a variety of distinct pathological events. Resident non-neuronal brain cells respond rapidly to neuronal cell death and may have both deleterious and useful role in neuronal damage. There is increasing evidence that reactive gliosis and post-ischemic inflammation involving microglia contribute to ischemic damage. We have demonstrated that FK506 modulates hypertrophic/proliferative responses and proinflammatory cytokine expression in astrocytes and microglia in vitro and in focal transient brain ischemia. Our findings suggest that astrocytes and microglia are direct targets of FK506 and modulation of glial response and inflammation is a possible mechanism of FK506-mediated neuroprotection in ischemia.
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PMID:Molecular mechanisms of neuroprotective action of immunosuppressants--facts and hypotheses. 1509 Feb 60

While the immunosuppressant tacrolimus (FK506) is known to be neuroprotective following cerebral ischemia, the mechanisms underlying its neuroprotective properties are not fully understood. To determine the mode of action by which tacrolimus ameliorates neurodegeneration after transient focal ischemia, we therefore evaluated the effect of tacrolimus on DNA damage, release of cytochrome c, activation of microglia and infiltration of neutrophils following a 60-min occlusion of the middle cerebral artery (MCA) in rats. In this model, cortical brain damage gradually expanded until 24 h after reperfusion, whereas brain damage in the caudate putamen was fully developed within 5 h. Tacrolimus (1 mg/kg) administered immediately after MCA occlusion significantly reduced ischemic damage in the cerebral cortex, but not in the caudate putamen. Tacrolimus decreased both apoptotic and necrotic cell death at 24 h and reduced the number of cytochrome c immunoreactive cells at 8 h after reperfusion in the ischemic penumbra in the cerebral cortex. In contrast, tacrolimus did not show significant neuroprotection for necrotic cell death and reduction of cytochrome c immunoreactive cells in the caudate putamen. Tacrolimus also significantly decreased microglial activation at 8 h and inflammatory markers (cytokine-induced neutrophil chemoattractant and myeloperoxidase [MPO] activity) at 24 h after reperfusion in the ischemic cortex but not in the caudate putamen. These results collectively suggest that tacrolimus ameliorates the gradually expanded brain damage by inhibiting both apoptotic and necrotic cell death, as well as suppressing inflammatory reactions.
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PMID:Multiple modes of action of tacrolimus (FK506) for neuroprotective action on ischemic damage after transient focal cerebral ischemia in rats. 1521 98

Ischemia-reperfusion (I-R) injury is poorly tolerated by fatty livers, most probably secondary to reduced cellular adenosine triphosphate (ATP) levels. We investigated the effectiveness of tacrolimus pretreatment on fatty liver I-R injury in obese Zucker rats. Tacrolimus (0.3 mg/kg, intravenously) was injected 24 hours before a 75-minute ischemic period and rats were sacrificed 6 hours later. Tacrolimus modified the response to I-R observed in obese Zucker rats, when compared to nontreated obese rats: a significant reduction in hepatocyte necrosis was associated with a significant increase in hepatocyte apoptosis. In addition, cell necrosis and apoptosis were significantly and inversely correlated in lean nontreated and treated obese Zucker rats following I-R. Tacrolimus also significantly increased the hepatic ATP levels, reduced in nontreated obese rats, toward values found in lean Zucker rat livers. This protective effect of tacrolimus was further confirmed in vivo by a significantly improved survival following pretreatment with tacrolimus, 24 hours prior to ischemia. In conclusion, in obese Zucker rat livers, tacrolimus pretreatment reversed the I-R injury toward the one found in lean Zucker rats. The correlations between ATP levels and the opposite changes in necrosis and apoptotic pathways strongly suggest a cause-effect relationship between tacrolimus and changes in ATP levels.
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PMID:Warm ischemia-reperfusion injury is decreased by tacrolimus in steatotic rat liver. 1644 2

Between April 1995-December 2003, 1,324 deceased donor kidney transplantations were performed in 139 transplant institutes in Japan. Of these, 45 transplants were from heart-beating and 1,279 transplants were from non-heart-beating deceased donors (NHBDD). Clinical outcomes for the 1,279 recipients of NHBDD kidney transplants were investigated. The overall 5-year patient and graft survival rates were 90% and 72%, respectively. A total of 112 NHBDD kidney grafts never functioned after transplantation and the recipients had to remain on dialysis. The causes of nonfunction were rejection, primary nonfunction, death, thrombosis and others in the order of the incidence. The major causes of graft loss were nonfunction, death, chronic rejection and acute rejection in that order. Major causes of recipient deaths were pneumonia, sepsis and CVA within 12 months, and heart diseases, sepsis, malignancy and pneumonia more than 12 months after transplantation. Kidneys from female donors, donors aged 15 or less or over age 60, donors with extrinsic causes of death other than head trauma, recipients over age 60 and those with diabetic nephropathy as their original disease were found to be at risk for poor graft survival. The lowest and last donor serum creatinine level did not influence the incidence of nonfunction or graft survival. However, graft survival was significantly poorer among recipients of older "expanded" donor kidneys than for recipients of younger grafts. The warm and total ischemia times should be kept shorter than 30 minutes (better 15 minutes), and 12 hours, respectively to minimize the incidence of nonfunction and early graft loss. It is especially important in cases with WIT over 30 minutes that the total ischemia should be kept within 12 hours. Cannulation before cardiac standstill was important to reduce the incidence of nonfunction and achieve high graft survival rates with NHBDD kidneys. The discontinuance of ventilator support also reduced the incidence of graft nonfunction. The combination of CsA or Tacrolimus and MMF as both the induction and maintenance regimen significantly improved graft survival. The use of either anti-T cell antibodies or basiliximab was also associated with significantly better graft survival for NHBDD kidneys. The combination of basiliximab, CsA and MMF resulted in a graft survival rate of 98% at one and 2 years.
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PMID:Outcomes of kidney transplants from non-heart-beating deceased donors as reported to the Japan Organ Transplant Network from April 1995-December 2003: a multi-center report. 1670 41

Tacrolimus (FK506) has a neuroprotective action on cerebral infarction produced by cerebral ischemia, however, detailed mechanisms underlying this action have not been fully elucidated. We examined temporal profiles of survival-and death-related signals, Bad phosphorylation, release of cytochrome c (cyt.c), activation of caspase 3 and DNA fragmentation in the brain during and after middle cerebral artery occlusion (MCAo) in mice, and then examined the effect of tacrolimus on these signals. C57BL/6J mice were subjected to transient MCAo by intraluminal suture insertion for 60 min. Tacrolimus (1 mg/kg, i.p.) was administered immediately after MCAo. There were biphasic increases in the release of cyt.c in the ischemic core and penumbra; with the first increase toward the end of the occlusion period and the second increase 3-12 h after reperfusion. Tacrolimus significantly inhibited the increase of cytosolic cyt.c during ischemia and reperfusion. Phosphorylated Bad, Ser-136 (P-Bad(136)) and Ser-155 (P-Bad(155)) were detected 30 min after MCAo and after reperfusion in the ischemic cortex, respectively. Tacrolimus increased P-Bad(136) during ischemia and prolonged P-Bad(155) expression after reperfusion. Tacrolimus also decreased caspase-3 and terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling-positive cells, and reduced the size of infarct 24 h after reperfusion. Our study provided the first evidence that the neuroprotective action of tacrolimus involved inhibition of biphasic cyt.c release from mitochondria, possibly via up-regulation of Bad phosphorylation at different sites after focal cerebral ischemia and reperfusion.
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PMID:Tacrolimus (FK506) attenuates biphasic cytochrome c release and Bad phosphorylation following transient cerebral ischemia in mice. 1693 31

Calcineurin inhibitors (CNIs) are routinely used in immunosuppressive therapy and both Cyclosporine (CsA) and Tacrolimus (FK506) show similar efficacies to prevent rejection and death within the first year after organ transplantation. However, their use is limited by side effects such as kidney damage, hypertension, onset of diabetes and hyperlipidemia. It is a consensus that compared with CsA, FK506 causes less changes in blood pressures, serum lipids and renal function. Nevertheless, FK506 use is associated with a higher incidence of post-transplant diabetes mellitus (PTDM). FTY720 is a new compound that has shown a protective effect in animal models with respect to rejection in transplantation, ischemia-reperfusion injury, autoimmune diseases and tumor development. FTY720 acts by altering lymphocytes homing from blood to peripheral lymphoid organs. In mice, FTY720 administered in combination with CsA during 21 days has prolonged skin allograft survival without causing significant renal changes. In a model of CsA-induced chronic nephropathy in rats, FTY720 administration prevented renal injury suggesting benefit from using a combination of these drugs. In a canine kidney allograft model, FTY720 in combination with low doses of CsA or FK506 showed an addictive anti-rejection effect without causing critical adverse effects. We therefore, investigated whether 21 days of FTY720 administration in association with FK506 could prevent renal damage and development of diabetes in mice. Mice receiving FK506 alone or FTY720 + FK506 during 21 days showed changes in kidney function and structure besides an increase in blood glucose and lymphopenia. The FTY720 + FK506 combination requires further investigation with an aim toward understanding the mechanisms involved with respect to side effects.
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PMID:Tacrolimus in combination with FTY720--an analysis of renal and blood parameters. 1721 91


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