tacrolimus and Brain-Infarction

The immunosuppressant drug rapamycin was reported to have an antiaging activity, which was attributed to the TORC1 inhibition that inhibits cell proliferation and increases autophagy. However, rapamycin also exhibits a number of harmful adverse effects. Whether rapamycin can be developed into an antiaging agent remains unclear.. We demonstrated that rapamycin at micro-doses (below the TORC1 inhibiting concentration) exhibits a cell-protective activity: (1) It protects cultured neurons against neurotoxin MPP(+) and H2O2. (2) It increases survival time of neuron in culture. (3) It maintains the nonproliferative state of cultured senescent human fibroblasts and prevents cell death induced by telomere dysfunction. (4) In animal models, it decreased the cerebral infarct sizes induced by acute ischemia and dramatically extended the life span of stroke prone spontaneously hypertensive rats (SHR-SPs).. We propose that rapamycin at micro-dose can be developed into an antiaging agent with a novel mechanism.

Topics: Aging; Animals; beta-Galactosidase; Brain Infarction; Brain Ischemia; Cell Death; Cell Line, Transformed; Cerebral Cortex; Disease Models, Animal; Fibroblasts; Humans; Hydrogen Peroxide; Immunosuppressive Agents; Male; Mice, Inbred C57BL; Phosphorylation; Rats; Rats, Inbred SHR; Rats, Sprague-Dawley; Signal Transduction; Sirolimus; Tacrolimus

Tropisetron is widely used to counteract chemotherapy-induced emesis. Evidence obtained from human and animal studies shows that tropisetron possesses anti-inflammatory properties. In this study, we assessed the effect of tropisetron on brain damage in a rat thromboembolic model of stroke. Stroke was rendered in rats by introduction of an autologous clot into the middle cerebral artery (MCA). Tropisetron (1 or 3mg/kg); m-chlorophenylbiguanide (mCPBG), a selective 5-HT(3) receptor agonist (15 mg/kg); tropisetron (3mg/kg) plus mCPBG (15 mg/kg); granisetron (3mg/kg); tacrolimus (1mg/kg); or tacrolimus (1mg/kg) plus tropisetron (3mg/kg) were administered intraperitoneally 1h prior to embolization. Behavioral scores and infarct volume as well as myeloperoxidase (MPO) activity and tumor necrosis factor-alpha (TNF-α) level were determined in the ipsilateral cortex 4h and 48 h following stroke induction. Forty-eight hours after embolization, tropisetron (1 or 3mg/kg), tropisetron (3mg/kg) plus mCPBG (15 mg/kg), tacrolimus (1mg/kg), or tacrolimus (1mg/kg) plus tropisetron (3mg/kg) significantly curtailed brain infarction, improved behavioral scores, diminished elevated tissue MPO activity, and reduced TNF-α levels compared to control group (n=6; P<0.05). mCPBG or granisetron had no effect on the mentioned parameters. Tropisetron attenuates brain damage after a thromboembolic event. Beneficial effects of tropisetron in this setting are receptor independent.

Topics: Analysis of Variance; Animals; Biguanides; Blood Gas Analysis; Brain Edema; Brain Infarction; Brain Injuries; Cerebral Cortex; Disease Models, Animal; Dose-Response Relationship, Drug; Immunosuppressive Agents; Indoles; Ischemia; Male; Nervous System Diseases; Peroxidase; Rats; Rats, Wistar; Seizures; Serotonin Antagonists; Stroke; Tacrolimus; Tropisetron; Tumor Necrosis Factor-alpha

Many practical therapies have been explored as clinical applications for ischemic cerebral infarction; however, most are still insufficient to treat acute stroke. We show here a potential combination therapy in a rat focal ischemic model to improve neurological symptoms as well as to reduce infarct volumes at the maximum level. We applied protein transduction technology using artificial anti-death Bcl-xl derivative with three amino acid-substitutions (Y22F, Q26N and R165K) (FNK) protein fused with a protein-transduction-domain peptide (PTD-FNK). When PTD-FNK was administrated 1 h after initiating ischemia followed by the administration of an immunosuppressant FK506 with a 30-min time lag, infarct volumes of the total brain and cortex were markedly reduced to 27% and 14%, respectively. This procedure not only reduced the infarct volume and edema, but also markedly improved neurological symptoms. The therapeutic effect continued for at least 1 week after ischemia. FK506 inhibited the transduction of PTD-FNK in vitro, which explains the requirement of a time lag for the administration of FK506. An additional in vitro experiment showed that PTD-FNK, when administered 30 min before FK506, gave the maximal protective effect by reducing the intracellular calcium concentration. We propose that this combination therapy would provide a synergistic protective effect by both drugs, reducing adverse the effects of FK506.

Topics: Animals; Apoptosis; Brain Infarction; Calcium Signaling; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Hypoxia-Ischemia, Brain; Immunosuppressive Agents; Ischemic Attack, Transient; Male; Peptide Fragments; Protein Serine-Threonine Kinases; Rats; Rats, Sprague-Dawley; Recombinant Fusion Proteins; Tacrolimus; Transduction, Genetic; Treatment Outcome

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.

Topics: Analysis of Variance; Animals; bcl-Associated Death Protein; Blotting, Western; Brain Infarction; Cytochromes c; Disease Models, Animal; Immunohistochemistry; Immunosuppressive Agents; In Situ Nick-End Labeling; Ischemic Attack, Transient; Male; Mice; Mice, Inbred C57BL; Phosphorylation; Tacrolimus; Time Factors

Ginkgo biloba exerts many pharmacological actions. It possesses antioxidant properties, the ability of neurotransmitter/receptor modulation and antiplatelet activation factor. This research is designed to investigate the neuroprotective effects of long-term treatment with EGb761 (a standard form of the extract of Ginkgo biloba leaf) in combination with MgSO(4), FK506, or MK-801 on the infarct volume of male gerbils' brain induced by unilateral middle cerebral artery occlusion (MCAO). Thirty-five gerbils fed a standard diet were intragastrically given water or EGb761 (100 mg/kg/day) for one week. Five randomized groups were established: control (n = 7), EGb761 (n = 8), EGb761 + MgSO(4) (n = 7), EGb761 + FK506 (n = 7), and EGb761 + MK-801 (n = 6). The three drug-combination groups were injected with MgSO(4) (90 mg/kg), FK506 (0.5 mg/kg), or MK-801 (1 mg/kg), respectively 30 min before MCAO. Gerbils were anesthetized and craniectomized to expose the right middle cerebral artery (MCA). The right MCA was constricted with an 8-0 suture to produce a permanent ligation for 24 hours. Postmortem infarct volumes were determined by quantitative image analysis of 2,3,5-triphenyltetrazolium chloride (TTC)-stained brain sections. Results showed that the total infarct volumes of the four treated groups either EGb761 alone or in combination with drugs were lower than the control group by 36.1% (EGb761 alone), 40.3% (EGb761 + MgSO(4)), 35.3% (EGb761 + FK506), and 56.4% (EGb761 + MK-801), respectively (p < 0.01). The main affected areas of the brain in the four treated groups were significantly focused between 4 and 6 mm from the frontal pole, when compared to the control group (p < 0.01). All animals in the five groups had infarctions in both cortex and subcortex. These results indicate that long-term pre-treatment of EGb761 administered either alone or in combination with drugs significantly effective neuroprotection on infarct volume in gerbil ischemic brains.

Topics: Animals; Brain Infarction; Brain Ischemia; Dizocilpine Maleate; Drug Therapy, Combination; Gerbillinae; Ginkgo biloba; Infarction, Middle Cerebral Artery; Magnesium Sulfate; Male; Neuroprotective Agents; Plant Extracts; Random Allocation; Tacrolimus; Treatment Outcome

It has been reported that immunosuppressant FK506 inhibited ischemic neuronal injury in forebrain ischemia or transient focal cerebral ischemia, but the mechanisms of the neuroprotective effect have not been clarified. In permanent focal cerebral ischemia, we investigated whether FK506 caused remission of brain infarction, and how mechanism was concerned. Male Balb/c mice were subjected to permanent middle cerebral artery (MCA) occlusion. They were treated with 1.0 or 3.0 mg/kg FK506 or vehicle 30 min before ischemia. Infarct volume was assessed by 2,3,5-triphenyltetrazolium chloride (TTC) method after 24 h. Cytochrome c release from mitochondria was evaluated by Western blotting and immunocytochemistry after ischemia. Simultaneously, the immunoreactivity of total and phosphorylated BAD was also studied using immunocytochemistry. We demonstrated that pretreatment with 3.0 mg/kg FK506 salvaged the tissue damage in the infarct rim and significantly reduced infarct volume to 75.5% (P<0.05), and FK506 inhibited cytochrome c release on 6 h after ischemia for Western blot analysis (P<0.05). Immunocytochemical study showed that permanent MCA occlusion increased the amount of cytochrome c and total BAD in the cytosol, but not phosphorylated BAD, in the ischemic core and the infarct rim as early as 1 h after ischemia, and FK506 inhibited the increases in the infarct rim. The results suggest that FK506 may, at least in part, ameliorate tissue damage due to permanent focal cerebral ischemia in the infarct rim through maintaining BAD turnover and inhibiting cytochrome c release from mitochondria.

Topics: Analysis of Variance; Animals; bcl-Associated Death Protein; Blotting, Western; Brain Infarction; Carrier Proteins; Cytochromes c; Dose-Response Relationship, Drug; Immunohistochemistry; Immunosuppressive Agents; Infarction, Middle Cerebral Artery; Male; Mice; Mice, Inbred BALB C; Neocortex; Phosphorylation; Tacrolimus; Tetrazolium Salts; Time Factors