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)

Neonatal rats were subjected to transient cerebral hypoxic-ischemia (unilateral occlusion of the common carotid artery + 7.70% O2 for 100 min) and allowed to recover for 3 h, 24 h, 2 days or 14 days. Consecutive tissue sections were stained with antibodies against alpha-fodrin, the 150 kDa breakdown product of alpha-fodrin (FBDP, marker of calpain proteolysis) or microtubule associated protein 2 (MAP 2, marker of dendrosomatic neuronal injury). Cortical tissue pieces were subjected to Western blotting using the antibody against the FBDP. Areas with brain injury displayed a distinct loss of MAP 2 which clearly delineated the infarct. FBDP accumulated in injured and borderline regions ipsilaterally and a less conspicuous, transient increase in FBDP also occurred in the contralateral hemisphere, especially in the white matter. A reciprocal staining pattern could be seen in the cerebral cortex, i.e. loss of MAP 2 and accumulation of FBDP, most pronounced 14 days after the insult. Fodrin and MAP 2 are known calpain substrates, and degradation of these proteins preceded neuronal degeneration, indicating that these proteases may be involved in the early events triggering the cascades leading to neuronal death.
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PMID:Degradation of fodrin and MAP 2 after neonatal cerebral hypoxic-ischemia. 758 14

Neonatal rats were subjected to transient cerebral hypoxic-ischemia (HI, unilateral occlusion of the common carotid artery +7.70% O2 for 100 min) and allowed to recover for up to 14 days. Calpain caseinolytic activity was found to increase in both hemispheres for at least 20 hr. Hypoxic exposure per se increased the activity of calpains, more pronounced in a membrane-associated fraction, probably through interaction with cellular components, whereas HI introduced a loss of activity, most likely through consumption and loss of proteases. Consecutive tissue sections were stained with antibodies against calpastatin, alpha-fodrin, the 150-kDa breakdown product of alpha-fodrin (FBDP, marker of calpain proteolysis) or microtubule-associated protein 2 (MAP-2, marker of dendrosomatic neuronal injury). Areas with brain injury displayed a distinct loss of MAP-2, which clearly delineated the infarct. FBDP accumulated in injured and borderline regions ipsilaterally, and a less conspicuous, transient increase in FBDP also occurred in the contralateral hemisphere, especially in the white matter. The cytosolic fraction (CF) and the membrane and microsomal fraction (MMF) of cortical tissue were subjected to Western blotting and stained with antibodies against calpain, calpastatin and the 150-kDa breakdown product of alpha-fodrin (FBDP). Calpain immunoreactivity decreased bilaterally in the CF during the insult (62-68% of controls) and remained significantly lower during early recovery, whereas the MMF showed no significant changes. This translocation of calpains coincided with the appearance of FBDP in the ipsilateral, HI hemisphere, displaying a significantly higher level of FBDP from immediately after the insult until at least 1 day of recovery (204-292% of controls). No significant changes in FBDP were found in the contralateral, undamaged hemisphere, despite translocation of calpains in both hemispheres, a prerequisite for calpain activation. This discrepancy may be related to changes in the endogenous inhibitor, calpastatin. Calpastatin protein was found to decrease during and shortly after HI in the ipsilateral, but not the contralateral, hemisphere. The inhibitory activity of calpastatin also tended to decrease after HI, indicating that a reduction of calpastatin may be necessary for extensive calpain activation to occur. The mRNA of m-calpain increased in the HI hemisphere 48 hr after the insult (167%, p < 0.001), a time point when the protein was also increased. In summary, our findings indicate that calpains are activated during HI and in the early phase of reperfusion after HI, preceding neuronal death.
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PMID:The calpain proteolytic system in neonatal hypoxic-ischemia. 936 79

A membrane cytoskeletal protein, fodrin, is a substrate for a Ca2+-dependent protease, calpain. It remains unknown whether mu-calpain or m-calpain is involved in the proteolysis of either alpha- or beta-fodrin and in what subcellular localization during ischemia and reperfusion of the brain. To address these issues, we examined the distribution of fodrin and calpain and the activities of calpain and calpastatin (endogenous calpain inhibitor) in the same subcellular fractions. Rat forebrain was subjected to ischemia by a combination of occlusion of both carotid arteries and systemic hypotension, whereas reperfusion was induced by releasing the occlusion. Immunoblotting, activity measurement, and casein zymography did not detect the presence of mu-calpain or a significant change of m-calpain level after ischemia or reperfusion. However, casein zymography revealed a unique Ca2+-dependent protease that was eluted with both 0.18 and 0.40 M NaCl from a DEAE-cellulose column. Alpha- and beta-fodrins and m-calpain were found to be rich in the synaptosomal, nuclear, and cytosolic subfractions by immunoblotting analysis. Reperfusion (60 min) following ischemia (30 min) induced selective proteolysis of alpha-fodrin, which was inhibited by a calpain inhibitor, acetylleucylleucylnorleucinal (400 microM, 1 ml, i.v.). The mu-calpain-specific fragment of beta-fodrin was not generated during ischemia-reperfusion, supporting the possibility of the involvement of m-calpain rather than mu-calpain in the alpha-fodrin proteolysis.
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PMID:Postischemic reperfusion induces alpha-fodrin proteolysis by m-calpain in the synaptosome and nucleus in rat brain. 960 18

Reperfusion of ischemic tissue causes an immediate increase in DNA damage, including base lesions and strand breaks. Damage is reversible in surviving regions indicating that repair mechanisms are operable. DNA strand breaks are repaired by nonhomologous end joining in mammalian cells. This process requires DNA-dependent protein kinase (DNA-PK), composed of heterodimeric Ku antigen and a 460,000 Da catalytic subunit (DNA-PKcs). In this study, a rabbit spinal cord model of reversible ischemia was used to demonstrate the effect of acute CNS injury on the activity and expression of DNA-dependent protein kinase. The DNA-binding activity of Ku antigen, analyzed by an electrophoretic mobility shift assay, increased during reperfusion after a short ischemic insult (15 min of occlusion), from which the animals recover neurological function. After severe ischemic injury (60 min of occlusion) and reperfusion that results in permanent paraplegia, Ku DNA binding was reduced. Protein levels of the DNA-PK components-Ku70, Ku80, and DNA-PKcs-were monitored by immunoblotting. After 60 min of occlusion, the amount of DNA-PKcs and the enzyme poly(ADP-ribose) polymerase (PARP) decreased with the same time course during reperfusion. Concurrently 150 and 120 kDa fragments were immunostained by an anti-DNA-PKcs monoclonal antibody. This antibody was shown to cross-react with alpha-fodrin breakdown products. The 120 kDa fodrin peptide is associated with caspase-3 activation during apoptosis. Both DNA-PKcs and PARP are also substrates for caspase-3-like activities. The results are consistent with a model in which after a short ischemic insult, DNA repair proteins such as DNA-PK are activated. After severe ischemic injury, DNA damage overwhelms repair capabilities, and cell death programs are initiated.
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PMID:Changes in expression of the DNA repair protein complex DNA-dependent protein kinase after ischemia and reperfusion. 1036 6

Testicular torsion requires emergent release of the twisted spermatic cord. Ischemia/reperfusion (I/R) plays an important role in its pathogenesis, and recent data suggest that germ cells undergo apoptosis during I/R. In a model of torsion/detorsion (i.e., I/R) of the rat testis, involvement of calpain and caspase in necrotic and apoptotic cell death was examined. After 1 h of ischemia followed by 0, 0.5, 1, 6, or 24 h of reperfusion, the germ cells positively stained with in situ TUNEL, and DNA fragmentation, activation of caspase-3, and proteolysis of caspase substrates increased with time of reperfusion, demonstrating apoptosis. In addition, m-calpain activation and proteolysis of alpha-fodrin were increased during reperfusion, and its activation is thought to be involved in the necrosis. A calpain inhibitor, acety-leucyl-leucyl-norleucinal, inhibited the phenomena associated with apoptosis and necrosis induced by I/R, although a caspase inhibitor, Z-Val-Ala-Asp-fluoromethlyketone, only inhibited apoptotic changes. The inhibition of calpain but not caspase ameliorated the injury after 60 days of reperfusion following 1 h of ischemia. The calpain inhibitor injected just before reperfusion effectively suppressed alpha-fodrin proteolysis, suggesting its usefulness in the treatment of testicular torsion.
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PMID:Inhibition of calpain but not caspase protects the testis against injury after experimental testicular torsion of rat. 1105 63

The purpose of this study is to determine whether inducible nitric oxide synthase (iNOS) is involved in the pathogenesis of testicular ischemia-reperfusion (I/R) injury in association with germ cell death, through either necrosis or apoptosis. Western blot analysis showed that iNOS expression was markedly increased 1 h after ischemia, and was accompanied by a huge nitric oxide (NO) production, as measured by the Griess method, with a peak at 48 h of reperfusion. Immunohistochemistry showed that iNOS was expressed predominantly in the macrophage-like cells infiltrated in the interstitial tissues of the testis. Intraperitoneal injection of aminoguanidine (AMG) (400 mg/day), the inhibitor of iNOS, reduced NO production by 57.7% at 96 h of reperfusion. Calpain activation and proteolysis of alpha-fodrin induced by I/R were inhibited by AMG. Germ cell apoptosis was demonstrated by in situ TUNEL and DNA fragmentation on agarose gel electrophoresis. Germ cell apoptosis was maximally induced at 24 h of reperfusion, and was not inhibited by AMG. NO produced by iNOS in the delayed phase of reperfusion promoted alpha-fodrin proteolysis, which is closely associated with necrosis. Inducible NOS inhibition combined with calpain inhibition may improve impaired spermatogenesis after testicular torsion.
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PMID:Nitric oxide promotes germ cell necrosis in the delayed phase after experimental testicular torsion of rat. 1146 20

The aim of the present study was to examine the mechanisms of Ca2+ overload-induced contractile dysfunction in rat hearts independent of ischemia and acidosis. Experiments were performed on 30 excised cross-circulated rat heart preparations. After hearts were exposed to high Ca2+, there was a contractile failure associated with a parallel downward shift of the linear relation between myocardial O(2) consumption per beat and systolic pressure-volume area (index of a total mechanical energy per beat) in left ventricles from all seven hearts that underwent the protocol. This result suggested a decrease in O(2) consumption for total Ca2+ handling in excitation-contraction coupling. In the hearts that underwent the high Ca2+ protocol and had contractile failure, we found marked proteolysis of a cytoskeleton protein, alpha-fodrin, whereas other proteins were unaffected. A calpain inhibitor suppressed the contractile failure by high Ca2+, the decrease in O(2) consumption for total Ca2+ handling, and membrane alpha-fodrin degradation. We conclude that the exposure to high Ca2+ may induce contractile dysfunction possibly by suppressing total Ca2+ handling in excitation-contraction coupling and degradation of membrane alpha-fodrin via activation of calpain.
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PMID:Rat cardiac contractile dysfunction induced by Ca2+ overload: possible link to the proteolysis of alpha-fodrin. 1151 99

In the present study, we evaluated the time-course of caspase-3 activation, and the evolution of cell death following focal cerebral ischemia produced by transient middle cerebral artery occlusion in rats. Ischemia-induced active caspase-3 immunoreactivity in the striatum but not the cortex at 3 and 6 h time points post-reperfusion. Furthermore, using a novel approach to visualize enzymatic activity, deltaC-APP, a C-terminal cleavage product of APP generated by caspase-3, was found to immunolocalize to the same areas as active caspase-3. Double-labeling studies demonstrated co-localization of these two proteins at the cellular level. Further double-labeling experiments revealed that active caspase-3 was confined to neuronal cells which were still viable and thus immunoreactive for NeuN. DNA fragmentation, assessed histologically by terminal dUTP nick-end labeling (TUNEL), was observed in a small number of cells in the striatum as early as 3 h, but only began to appear in the cortex by 6 h. DNA fragmentation was progressive, and by 24 h post-reperfusion, large portions of both the striatum and cortex showed TUNEL positive cells. However, double-labeling of active caspase-3 with TUNEL showed only minimal co-localization at all time-points. Thus, caspase-3 activation is an event that appears to occur prior to DNA fragmentation. As a confirmation of the histological TUNEL data, 24 h ischemia also induced the generation of nucleosome fragments, evidenced by cell death enzyme-linked immunosorbent assay. Using a novel ischemia-induced substrate cleavage biochemical approach, spectrin P120 fragment, a caspase-specific cleavage product of alpha II spectrin, a cytoskeletal protein, was shown to be elevated by western blotting. Brain concentrations of both nucleosomes and spectrin P120 correlate with the degree of injury previously assessed by triphenyltetrazolium chloride staining and infarct volume calculation. Together, our findings suggest a possible association between caspase-3 activation and ischemic cell death following middle cerebral artery occlusion brain injury.
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PMID:Immunohistochemical and biochemical assessment of caspase-3 activation and DNA fragmentation following transient focal ischemia in the rat. 1240 27

We hypothesized that there are no differences in left ventricular (LV) mechanoenergetics between after hyperpolarized cardioplegic arrest by nicorandil (nicorandil arrest) and after depolarized one by high potassium chloride (KCl arrest). The aim of the present study was to test this hypothesis using LV curved end-systolic pressure-volume relation (ESPVR) and linear pressure-volume area (PVA)-myocardial oxygen consumption per beat (VO2) relation. All hearts underwent 30 min global ischemia (30 degrees C) after infusion of 5 ml of cardioplegia. Cardioplegia consisted of either 30 mmol/l KCl (7 hearts) or nicorandil (100 micromol/l) in Tyrode solution (6 hearts). After a 30-min blood reperfusion, ESPVR and VO2-PVA relation were assessed again. Mean end-systolic pressure (ESP(mLVV)) and mean PVA at midrange LV volume (PVA(mLVV)) significantly (P < 0.05) decreased to 79.1 +/- 13.4% and 85.4 +/- 17.1% of control after KCl arrest and to 85.3 +/- 14.8% and 86.4 +/- 16.9% of control after nicorandil arrest. There were no significant differences in both decreases of mean ESP(mLVV) and PVA(mLVV) between each arrest. The slopes of VO2-PVA relations were also unchanged after each arrest. There was a significant (P < 0.005) difference in the decreases of mean VO2 intercepts of VO2-PVA relations between post-KCl arrest (73.9 +/- 8.2% of control) and post-nicorandil arrest (99.2 +/- 10.1% of control), however. Proteolysis of alpha-fodrin due to Ca2+ overload was significantly marked after KCl arrest. The present results indicate that the total calcium handling in excitation-contraction coupling is transiently impaired after KCl arrest, whereas it is unchanged after nicorandil arrest. This suggests the possibility that nicorandil is a better cardioplegia than KCl.
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PMID:Left ventricular mechanoenergetics after hyperpolarized cardioplegic arrest by nicorandil and after depolarized cardioplegic arrest by KCl. 1510 68

We hypothesized that calpain inhibitor-1 protected left ventricular (LV) function from ischemia-reperfusion injury by inhibiting the proteolysis of alpha-fodrin. To test this hypothesis, we investigated the effect of calpain inhibitor-1 on LV mechanical work and energetics in the cross-circulated rat hearts that underwent 15-min global ischemia and 60-min reperfusion (n = 9). After ischemia-reperfusion with calpain inhibitor-1, mean end-systolic pressure at midrange LV volume and systolic pressure-volume area (PVA) at midrange LV volume (total mechanical energy per beat) were hardly changed, although they were significantly (P < 0.01) decreased after ischemia-reperfusion without calpain inhibitor-1. Mean myocardial oxygen consumption per beat (Vo(2)) intercepts (PVA-independent Vo(2); Vo(2) for the total Ca(2+) handling in excitation-contraction coupling and basal metabolism) of Vo(2)-PVA linear relations were also unchanged after ischemia-reperfusion with calpain inhibitor-1, although they were significantly (P < 0.01) decreased after ischemia-reperfusion without calpain inhibitor-1. There were no significant differences in O(2) costs of LV PVA and contractility among the hearts in control (or normal) postischemia-reperfusion and postischemia-reperfusion with calpain inhibitor-1. Western blot analysis of alpha-fodrin and the immunostaining of 150-kDa products of alpha-fodrin confirmed that calpain inhibitor-1 almost completely protected the proteolysis of alpha-fodrin. Our results indicate that calpain inhibitor-1 prevents the heart from ischemia-reperfusion injury associated with the impairment of total Ca(2+) handling by directly inhibiting the proteolysis of alpha-fodrin.
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PMID:Calpain inhibitor-1 protects the rat heart from ischemia-reperfusion injury: analysis by mechanical work and energetics. 1552 29


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