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J D Crapo

Publications and source records attributed to J D Crapo.

At least 19 recordsLinked to original sources
PubMed2004

Manganese superoxide dismutase is increased in the airways of smokers' lungs.

Oxidant stress is a key mechanism for smoking-induced chronic obstructive pulmonary disease (COPD). Smoking has been shown to upregulate several antioxidant enzymes, with potential effects on the prevention of the disease and/or its progression. Superoxide dismutases (SOD)s are the only enzymes capable of consuming superoxide radicals. The purpose of the present study was to investigate SODs in the lungs of nonsmokers, smokers and COPD patients. Manganese superoxide dismutase (MnSOD), copper zinc SOD (CuZnSOD), and extracellular SOD (ECSOD), were investigated by immunohistochemistry in the airways of 13 nonsmokers, 20 smokers and 22 COPD patients with mild-to-moderate disease. Lung tissue homogenates of three nonsmokers and four smokers were used for Western blot and enzyme activity analysis. The expression of MnSOD was higher in the central bronchial epithelium of smokers with COPD and in the alveolar epithelium of smokers without or with COPD than innonsmokers. Lung MnSOD immunoreactivity, evaluated by Western blotting and specific activity, were 33% and 51% higher, respectively, in smokers than in nonsmokers. No major changes could be observed in lung CuZnSOD or ECSOD immunoreactivities. Manganese superoxide dismutase is elevated in the alveolar epithelium of cigarette smokers, probably due to the increased oxidant burden in smokers' lungs.

Aged↗
PubMed2003

Oxidative stress as an initiator of cytokine release and cell damage.

This article characterised the role of oxidative stress in mediating pathological reactions in the lung and the unique antioxidant defences that the lung possesses. The impact of redox balance in regulating inflammatory and immune reactions were discussed, and the impact of enhancing lung antioxidant capacity in animal models of asthma and chronic obstructive pulmonary disease were characterised.

Animals↗
PubMed2001

Extracellular superoxide dismutase attenuates lung injury after hemorrhage.

Reperfusion of the lung after hemorrhage generates free radicals such as superoxide (O(2)(.)) that may injure the lung; however, the relative importance of intracellular versus extracellular free radicals is unclear. The superoxide dismutases (SOD) are the primary enzymatic method to reduce superoxide. We examined whether lung-specific overexpression of extracellular superoxide dismutase (EC-SOD) would attenuate hemorrhage-induced lung injury. Wild-type mice and mice overexpressing the human EC-SOD gene with a lung-specific promoter were hemorrhaged by removing 30% of blood volume. After hemorrhage, the lung wet to dry weight ratios increased from 5.4 +/- 0.11 in unmanipulated control mice to 6.3 +/- 0.16 in wild-type mice, but to only 5.60 +/- 0.17 in the EC-SOD transgenic mice (p < 0.05 compared with hemorrhaged wild-type). Hemorrhage-induced lipid peroxidation, as assessed by lung F(2) isoprostanes, was lower in the EC-SOD transgenic mice (3.4 +/- 0.3 microg/lung) compared with wild-type mice (1.9 +/- 0.2 microg/lung; p < 0.05). Compared with wild-type, EC-SOD transgenic mice had attenuated the hemorrhage-induced increase in both pulmonary nuclear factor kappa B (NK-kappaB) activation (relative absorbance 1.1 +/- 0.2 for EC-SOD transgenic versus 2.5 +/- 0.1 for wild-type; p < 0.05) and myeloperoxidase activity (5.1 +/- 0.87 units/g for EC-SOD transgenic versus 11.3 +/- 1.8 units/g for wild-type; p < 0.01). Thus, overexpression of pulmonary EC-SOD in the mouse lung attenuates lung injury after hemorrhage.

Animals↗
PubMed2001

Neuroprotection from delayed postischemic administration of a metalloporphyrin catalytic antioxidant.

Reactive oxygen species contribute to ischemic brain injury. This study examined whether the porphyrin catalytic antioxidant manganese (III) meso-tetrakis (N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+)) reduces oxidative stress and improves outcome from experimental cerebral ischemia. Rats that were subjected to 90 min focal ischemia and 7 d recovery were given MnTE-2-PyP(5+) (or vehicle) intracerebroventricularly 60 min before ischemia, or 5 or 90 min or 6 or 12 hr after reperfusion. Biomarkers of brain oxidative stress were measured at 4 hr after postischemic treatment (5 min or 6 hr). MnTE-2-PyP(5+), given 60 min before ischemia, improved neurologic scores and reduced total infarct size by 70%. MnTE-2-PyP(5+), given 5 or 90 min after reperfusion, reduced infarct size by 70-77% and had no effect on temperature. MnTE-2-PyP(5+) treatment 6 hr after ischemia reduced total infarct volume by 54% (vehicle, 131 +/- 60 mm(3); MnTE-2-PyP(5+), 300 ng, 60 +/- 68 mm(3)). Protection was observed in both cortex and caudoputamen, and neurologic scores were improved. No MnTE-2-PyP(5+) effect was observed if it was given 12 hr after ischemia. MnTE-2-PyP(5+) prevented mitochondrial aconitase inactivation and reduced 8-hydroxy-2'-deoxyguanosine formation when it was given 5 min or 6 hr after ischemia. In mice, MnTE-2-PyP(5+) reduced infarct size and improved neurologic scores when it was given intravenously 5 min after ischemia. There was no effect of 150 or 300 ng of MnTE-2-PyP(5+) pretreatment on selective neuronal necrosis resulting from 10 min forebrain ischemia and 5 d recovery in rats. Administration of a metalloporphyrin catalytic antioxidant had marked neuroprotective effects against focal ischemic insults when it was given up to 6 hr after ischemia. This was associated with decreased postischemic superoxide-mediated oxidative stress.

Aconitate Hydratase↗
PubMed2001

Attenuation of bleomycin-induced pulmonary fibrosis by a catalytic antioxidant metalloporphyrin.

Oxidative stress plays an important role in the development of fibrotic responses in the lung. However, it is not clear whether inhibiting oxidative stress with antioxidants can attenuate fibrotic processes in the lung. The objective of these studies was to test whether the catalytic antioxidant porphyrin manganese (III) tetrakis (4-benzoic acid) porphyrin (MnTBAP) could protect mice against bleomycin-induced lung fibrosis. A 10 mg/kg intraperitoneal dose of MnTBAP was established as safe and had a serum and lung half-life of 9.5 h in mice. Based on this data, four groups of mice were given one dose of bleomycin (3.2 U/kg, intratracheal) or saline and MnTBAP (5 mg/kg, intraperitoneal) or saline twice daily for 14 d. Lung fibrosis was assessed by measuring (1) lung hydroxyproline content as an index of collagen accumulation, (2) airway dysfunction by whole body plethysmography, and (3) histopathology. Bleomycin produced a 20% loss in body weight that was only 10% in the bleomycin/MnTBAP group. Bleomycin produced a twofold increase in hydroxyproline content that was decreased 23% by MnTBAP. Bleomycin produced a twofold increase in airway dysfunction that was also attenuated 30% by MnTBAP. Histopathologic analysis of the lungs of mice treated with bleomycin demonstrated a severe fibrotic response that was attenuated 28% by MnTBAP. Future studies on the oxidant mechanisms that MnTBAP is affecting in this bleomycin model of lung fibrosis may shed light on potential new therapeutic approaches for treating interstitial lung diseases.

Animals↗
PubMed2000

Purification and characterization of extracellular superoxide dismutase in mouse lung.

Extracellular superoxide dismutase (EC-SOD) is the major isozyme of SOD in arteries, but is also abundant in lungs. In particular, mouse lungs contain large amounts of EC-SOD compared to lungs in other mammals. This suggests that EC-SOD may have an amplified function in the mouse lung. This study describes the purification and characterization of mouse EC-SOD as well as its localization in mouse lung. Mouse EC-SOD exists primarily as a homotetramer composed of a pair of dimers linked through disulfide bonds present in the heparin-binding domains of each subunit. In addition, mouse EC-SOD can exist in active multimeric forms. We developed and utilized a polyclonal antibody to mouse EC-SOD to immunolocalize EC-SOD in mouse lung. EC-SOD labeling is strongest in the matrix of vessels, airways, and alveolar septa. This localization suggests that EC-SOD may have important functions in pulmonary biology, perhaps in the modulation of nitric oxide-dependent responses.

Amino Acid Sequence↗
PubMed2000

Mice overexpressing extracellular superoxide dismutase have increased resistance to global cerebral ischemia.

Transgenic mice, which exhibit a fivefold increase in brain parenchymal extracellular superoxide dismutase (EC-SOD) activity, were used to investigate the role of EC-SOD in global ischemic brain injury. Halothane-anesthetized normothermic wild-type (n = 22) and transgenic (n = 20) mice underwent 10 min of near-complete forebrain ischemia induced by bilateral carotid artery occlusion and systemic hypotension (mean arterial pressure = 30 mm Hg). After 3 days of recovery, the brains were histologically examined. Other mice underwent autoradiographic determination of regional CBF 10 min prior to, during, and 30 min after forebrain ischemia. Histologic injury in the cortex and caudoputamen was minimal in both groups. The percentage of dead hippocampal CA1 neurons was reduced in the EC-SOD transgenic group (wild type = 44 +/- 28%; EC-SOD transgenic = 23 +/- 21%, mean +/- SD, P = 0.015). CBF was similar between groups prior to ischemia. The intraischemic blood flow was severely reduced in forebrain structures and was similar between groups. Blood flow at 30 min postischemia had recovered to 50-60% of baseline values in both groups. These results indicate that EC-SOD can play an important role in defining the magnitude of selective neuronal necrosis resulting from near-complete forebrain ischemia. This implicates involvement of extracellular superoxide anions in the pathologic response to global cerebral ischemia.

Animals↗
PubMed2000

Molecular overexpression of extracellular superoxide dismutase increases the dependency of learning and memory performance on motivational state.

Extracellular superoxide dismutase (EC-SOD) controls the availability of extracellular superoxide and appears to play a role in controlling intercellular signaling. In this role EC-SOD can have potent effects on neurobehavioral function. In previous studies, we have found that either over- or under-expression of EC-SOD in mice significantly impairs spatial learning on the radial-arm maze. In the current study, the neurobehavioral nature of the EC-SOD role in cognitive function was determined. EC-SOD overexpression altered the relationship between both learning and memory with motivational state. Mice were tested in the radial-arm maze under a high motivational state (22-24 hours of food restriction) or a low motivational state (4-6 hours of food restriction). Under a high motivational state, the EC-SOD overexpressing mice were able to learn in the radial-arm maze, albeit at a slightly lower rate than wild-type controls. This contrasts with the failure to learn by EC-SOD overexpressing mice in our previous study conducted with the low motivational state. The change in motivational state did not significantly alter the learning rate of controls. Similarly, during postacquisition memory phase of testing, the EC-SOD overexpressing mice were significantly worse than controls when tested in a low motivational state but not under a high motivation state. As with learning, motivational state did not significantly affect memory performance in controls. This study shows that mice with EC-SOD overexpression are not incapable of learning and memory in the radial-arm maze, but that the mechanisms which allow control animals to perform this task well under low motivational states are deficient in the mice with EC-SOD overexpression.

Animals↗
PubMed2000

Differential localization of placental extracellular superoxide dismutase as pregnancy progresses.

OBJECTIVE: The aim of this study was to determine placental localization and activity of extracellular superoxide dismutase, a nitric oxide modulator, during early gestation and to correlate these characteristics with fetal vascular development. STUDY DESIGN: First-trimester (n = 10) and second-trimester (n = 10) villi were obtained at elective pregnancy termination. Extracellular superoxide dismutase was localized by means of an immunoperoxidase method. Activity was measured by determining the inhibition of cytochrome c reduction at pH 10 and messenger ribonucleic acid expression by in situ hybridization. RESULTS: Extracellular superoxide dismutase was intracellular within villous trophoblasts until 17 weeks' gestation, when it relocated to the villous extracellular matrix. Activities were similar between first- and second-trimester villi. In situ hybridization confirmed extracellular superoxide dismutase messenger ribonucleic acid within trophoblasts throughout gestation. CONCLUSION: Extracellular superoxide dismutase is produced by trophoblasts early in pregnancy, but it remains intracellular until 17 weeks' gestation, which may be related to fetal vascular development.

Blotting, Western↗
PubMed1999

Extracellular superoxide dismutase deficiency worsens outcome from focal cerebral ischemia in the mouse.

The role of endogenous extracellular superoxide dismutase (EC-SOD) was examined in a murine model of transient focal cerebral ischemia. Homozygous EC-SOD deficient (EC-SOD-/-; n = 18) and wild type (EC-SOD+/+; n = 19) littermates were anesthetized with halothane and subjected to 50 min of intraluminal middle cerebral artery occlusion with pericranial temperature maintained at 37.0 degrees C. After 24 h of reperfusion, resultant hemiparesis and cerebral infarct size were measured. Total infarct volume was 81% greater (P = 0.03) and hemiparesis was more severe (P = 0.01) in EC-SOD-/- versus EC-SOD+/+ mice. The worsened ischemic outcome observed in EC-SOD-/- mice is consistent with prior work which found transgenic EC-SOD overexpressing mice to exhibit enhanced tolerance to focal ischemia. The results suggest that endogenous antioxidant activity in the extracellular compartment plays an important role in the histologic/neurologic response to focal cerebral ischemia.

Animals↗
PubMed1999

The heparin-binding domain of extracellular superoxide dismutase is proteolytically processed intracellularly during biosynthesis.

Extracellular superoxide dismutase (EC-SOD) is the only known extracellular enzyme designed to scavenge the superoxide anion. The purified enzyme exists in two forms when visualized by reduced SDS-polyacrylamide gel electrophoresis: (i) intact EC-SOD (Trp1-Ala222) containing the C-terminal heparin-binding domain and (ii) cleaved EC-SOD (Trp1-Glu209) without the C-terminal heparin-binding domain. The proteolytic event(s) leading to proteolysis at Glu209-Arg210 and removal of the heparin-binding domain are not known, but may represent an important regulatory mechanism. Removal of the heparin-binding domain affects both the affinity of EC-SOD for and its distribution to the extracellular matrix, in which it is secreted. During the purification of human EC-SOD, the intact/cleaved ratio remains constant, suggesting that proteolytic removal of the heparin-binding domain does not occur during purification (Oury, T. D., Crapo, J. D., Valnickova, Z., and Enghild, J. J. (1996) Biochem. J. 317, 51-57). This was supported by the finding that fresh mouse tissue contains both intact and cleaved EC-SOD. To study other possible mechanisms leading to the formation of cleaved EC-SOD, we examined biosynthesis in cultured rat L2 epithelial-like cells using a pulse-chase protocol. The results of these studies suggest that the heparin-binding domain is removed intracellularly just prior to secretion. In addition, the intact/cleaved EC-SOD ratio appears to be tissue-dependent, implying that the intracellular processing event is regulated in a tissue-specific manner. The existence of this intracellular processing pathway may thus represent a novel regulatory pathway for affecting the distribution and effect of EC-SOD.

Animals↗
PubMed1999

Mice overexpressing extracellular superoxide dismutase have increased resistance to focal cerebral ischemia.

Transgenic mice, which had been transfected with the human extracellular superoxide dismutase gene, causing an approximate five-fold increase in brain parenchymal extracellular superoxide dismutase activity, were used to investigate the role of extracellular superoxide dismutase in ischemic brain injury. Transgenic (n = 21) and wild-type (n = 19) mice underwent 90 min of intraluminal middle cerebral artery occlusion and 24 h of reperfusion. Severity of resultant hemiparesis and cerebral infarct size were measured. Wild-type mice had larger infarcts (cortex: wild type =37+/-14 mm3, transgenic = 27+/-13 mm3, P=0.03; subcortex: wild type = 33+/-14 mm3, transgenic = 23+/-10 mm3, P = 0.02). Neurological scores, however, were similar (P = 0.29). Other mice underwent autoradiographic determination of intra-ischemic cerebral blood flow. The volume of tissue at risk of infarction (defined as volume of tissue where blood flow was <25 ml/100g/min) was similar between groups (cortex: wild type = 51+/-15 mm3, transgenic = 47+/-9 mm3, P=0.65; subcortex: wild type = 39+/-16 mm3, transgenic= 37+/-17 mm3, P=0.81). These results indicate that antioxidant scavenging of free radicals by extracellular superoxide dismutase plays an important role in the histological response to a focal ischemic brain insult.

Animals↗
PubMed1999

Metalloporphyrins are potent inhibitors of lipid peroxidation.

The objectives of these studies were to determine whether metalloporphyrins could inhibit lipid peroxidation, characterize factors that influence their potency and compare their potency to prototypical antioxidants. Lipid peroxidation was initiated with iron and ascorbate in rat brain homogenates and the formation of thiobarbituric acid reactive species was used as an index of lipid peroxidation. Metalloporphyrins were found to be a novel and potent class of lipid peroxidation inhibitors. Inhibition of lipid peroxidation by metalloporphyrins was dependent on the transition metal ligated to the porphyrin, indicating that metal centered redox chemistry was important to the mechanism of their antioxidant activities. Manganese porphyrins with the highest superoxide dismutase (SOD) activities, MnOBTM-4-PyP and MnTM-2-PyP (charges are omitted throughout text for clarity), were the most potent inhibitors of lipid peroxidation with calculated IC50s of 1.3 and 1.0 microM, respectively. These manganese porphyrins were 2 orders of magnitude more potent than either trolox (IC50 = 204 microM) or rutin (IC50 = 112 microM). The potencies of the manganese porphyrins were related not only to their redox potentials and SOD activities, but also to other factors that may contribute to their ability to act as electron acceptors. The broad array of antioxidant activities possessed by metalloporphyrins make them attractive therapeutic agents in disease states that involve the overproduction of reactive oxygen species.

Animals↗
PubMed1999

Cellular and connective tissue changes in alveolar septal walls in emphysema.

Emphysema is commonly defined as enlargement of airspaces distal to terminal bronchioles accompanied by destruction of alveolar walls, but without obvious fibrosis. Morphometric techniques were used to correlate changes in components of the alveolar septa surrounding enlarged airspaces in human emphysema with the mean linear intercept (Lm) of those airspaces. Alveolar and capillary surface density decreased with increased Lm, but the ratio of these surface densities to each other remained close to normal for mild to moderate increases in Lm. This suggests that the decreased gas exchange observed in emphysema is initiated by a total loss of septa and not by selective pathological changes of the microvasculature. Increases in septal wall thickness directly correlated with increases in Lm. For the mild to moderate emphysema lesions included in this study, an increase of 100% in Lm correlated with a 130% increase in the relative volume of the alveolar septal interstitium. Significant increases occurred in both elastin (0.14 to 0.56 microm(3)/microm(2) basement membrane [BM]) and collagen (0.49 to 1. 63 microm(3)/microm(2) BM). The increase in elastin and collagen raises the possibility of a remodeling process in the connective matrix in alveolar walls. Whether or not the new connective tissue represents a disordered, nonfunctional regional response needs to be determined.

Aged↗
PubMed1998

Molecular manipulations of extracellular superoxide dismutase: functional importance for learning.

Extracellular superoxide dismutase (EC-SOD) controls the availability of extracellular superoxide (O2.-), which is important for a variety of physiological pathways, including the primary means of inactivating nitric oxide (NO). The role of EC-SOD in neurobehavioral function has been until now unexplored. In the current studies, the phenotypic expression of genotypic alterations of EC-SOD production in mice were characterized for spatial learning and memory. Dramatic impairments in spatial learning in the win-shift 8-arm radial maze were seen in both EC-SOD knockout mice and EC-SOD overexpressing mice. The EC-SOD overexpressing mice were further characterized as having significant deficits in a repeated acquisition task in the radial-arm maze, which permitted the dissociation of long and short-term learning. Long-term learning was significantly impared by EC-SOD overexpression, whereas short-term learning was not significantly affected by EC-SOD overexpression. No systems have been shown to be importantly involved in learning and memory. This may be important in the current studies because EC-SOD has primary control over the inactivation of NO. We found that EC-SOD overexpressing mice were resistant to the cognitive effects of L-NAME (NG-nitro-L-arginine methyl ester hydrochloride), an NO synthase inhibitor. Decreased NO catabolism in these mice may have served to counter the effects of NOS inhibition by L-NAME. The current finding that EC-SOD levels that were either higher or lower than controls impaired learning demonstrates that the proper control of brain extracellular O2.- may be more vital than merely reduction of brain extracellular O2.- in maintaining adequate learning function.

Animals↗
PubMed1998

A novel neurological phenotype in mice lacking mitochondrial manganese superoxide dismutase.

Reactive oxygen species (ROS) have been implicated in a wide range of degenerative processes including amyotrophic lateral sclerosis, ischemic heart disease, Alzheimer disease, Parkinson disease and aging. ROS are generated by mitochondria as the toxic by-products of oxidative phosphorylation, their energy generating pathway. Genetic inactivation of the mitochondrial form of superoxide dismutase in mice results in dilated cardiomyopathy, hepatic lipid accumulation and early neonatal death. We report that treatment with the superoxide dismutase (SOD) mimetic Manganese 5, 10, 15, 20-tetrakis (4-benzoic acid) porphyrin (MnTBAP) rescues these Sod2tm1Cje(-/-) mutant mice from this systemic pathology and dramatically prolongs their survival. The animals instead develop a pronounced movement disorder progressing to total debilitation by three weeks of age. Neuropathologic evaluation reveals a striking spongiform degeneration of the cortex and specific brain stem nuclei associated with gliosis and intramyelinic vacuolization similar to that observed in cytotoxic edema and disorders associated with mitochondrial abnormalities such as Leighs disease and Canavans disease. We believe that due to the failure of MnTBAP to cross the blood brain barrier progressive neuropathology is caused by excessive mitochondrial production of ROS. Consequently, MnTBAP-treated Sod2tm1Cje(-/-) mice may provide an excellent model for examining the relationship between free radicals and neurodegenerative diseases and for screening new drugs to treat these disorders.

Animals↗