Toxicity of oxygen and (Cu) superoxide dismutase and (Mn) superoxide dismutase in newborn infants with respiratory distress. Preliminary results

Twelve premature newborns mechanically ventilated with high FiO2 for hyaline membrane disease were tested for SOD contents during their first two weeks of life. CuSOD and MnSOD were measured in plasma, platelets and red cells using a radioimmunology method. No correlation was found between FiO2 levels neither with CuSOD and MnSOD contents. Furthermore no correlation was found between the SOD contents, at birth, and the constitution of bronchopulmonary dysplasia (BPD). Our results don't prove any relationship between lack of SOD and BPD. BPD pathogeny is certainly plurifactorial. Other protecting systems against O2 toxicity are also known to play an important role.     

Differential expression of superoxide dismutases in lung cancer

Oxidant-antioxidant balance is known to regulate growth factors and invasion of tumor cells. Manganese superoxide dismutase (MnSOD), copper zinc SOD (CuZnSOD), and extracellular SOD (ECSOD), the first-line antioxidant defenses, were studied in lung carcinomas by immunohistochemical analysis (n = 139, 56, and 37, respectively) and in 8 lung tumor specimens by Western blot analysis and SOD activity measurement. Altogether, 49% of squamous cell carcinomas and 43% of the adenocarcinomas were positive for MnSOD by immunohistochemical analysis; corresponding values for CuZnSOD were 79% and 93%, respectively. MnSOD and CuZnSOD by Western blot analysis were 27% and 22% higher, and CuZnSOD activity was 93% higher (P = .06) in carcinomas than in nonmalignant lung tissue samples. ECSOD, a mainly extracellular enzyme, showed weak positivity only in 4 of 37 carcinomas, and by Western blot analysis showed 70% lower immunoreactivity (P < .0001) than in nonmalignant lung tissue samples. It is highly likely that low expression of ECSOD might have fundamental effects on the extracellular redox state of lung tumors with potential consequences on tumor behavior.     

Activities of superoxide dismutases and NADPH oxidase in neutrophils obtained from asthmatic and normal donors

PMN obtained from asthmatic subjects demonstrate a heightened respiratory burst with increased superoxide generation compared to normals. This enhanced superoxide anion generation could be secondary to increased activity of the respiratory burst NADPH oxidase or diminished metabolism of superoxide via superoxide dismutase (SOD). The two forms of SOD expressed in PMN, CuZnSOD expressed constitutively in the cytosol and inducible mitochondrial MnSOD, were investigated in asthmatics. Resting ?MN from asthmatics (N = 9) contained significantly less MnSOD activity compared to controls (0.46 ± 0.16 vs. 0.79 ± 0.17 units/10⁷ PMN, respectively;P=0.0002). As several cytokines including interleukins (IL) -1, -4, and -6 as well as granulocyte macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor (TNF) enhance the PMN respiratory burst and are synthesized in the asthmatic lung, their effects on PMN MnSOD activity were assayed. In contrast to its effects on lymphocytes, both IL-1 and IL-6 significantly inhibited in a dosedependent fashion the induction of MnSOD in PMN from normals (0.42 ± 0.12 and 0.45 ± 0.05 units/10⁷ PMN, respectively, at 10 units/ml of each cytokine;P=0.02 compared to resting cells) but failed to further modulate MnSOD production in asthmatic PMN. IL-4 and GM-CSF had no effect on MnSOD production, and TNF effects could not be studied because of its effects on cell viability. There were no differences in the activity of CuZnSOD (N=9) or NADPH oxidase (N = 4) in the two groups. Inhibition of MnSOD activity in PMN secondary to cytokine exposure in the asthmatic lung could explain, at least in part, the increased generation of superoxide from PMN obtained from asthmatics. This would promote the presence and severity of inflammation in the asthmatic lung. These data further support a role for IL-1 and IL-6 in allergic inflammation.     

Surfactant apoprotein in nonmalignant pulmonary disorders.

Formalin-fixed, paraffin-embedded lungs exhibiting a variety of nonmalignant disorders were studied by immunoperoxidase staining using antibodies specific for surfactant apoprotein, IgG, IgM, IgA, albumin, fibrinogen, and lysozyme. Normal Type II pneumocytes showed staining for surfactant apoprotein in the perinuclear region only. The extent and intensity of staining for apoprotein was markedly increased in reactive Type II pneumocytes. This increase appeared to be a nonspecific reaction to lung injury. The intra-alveolar material in pulmonary alveolar proteinosis stained intensely for surfactant apoprotein, indicating that the accumulated proteinaceous material contained pulmonary surfactant. Type II pneumocytes in pulmonary alveolar proteinosis exhibited hyperplasia as well as hypertrophy. The few macrophages in lung affected by pulmonary alveolar proteinosis stained intensely for lysozyme. The excessive intraalveolar accumulation of proteinaceous material in pulmonary alveolar proteinosis may be the result of both an over-production as well as a deficient removal of pulmonary surfactant.     

Ontogeny of neuroendocrine cells in human fetal lung. II. An immunohistochemical study

Immunocytochemistry using horseradish peroxidase-antiperoxidase technique was performed on the lungs of 60 human fetuses and newborn infants of 8 to 40 weeks' gestation and from birth to 7 months' postnatal life. Tissue was stained for the peptide hormones, immunoreactive (IR) bombesin, IR calcitonin and IR Leu-enkephalin, as well as for IR serotonin. IR bombesin appeared in neuroendocrine cells and neuroepithelial bodies in the developing conducting airways of fetuses by 10 weeks' gestation and increased in number primarily in bronchioles as gestation progressed. They were most numerous in live-born infants with chronic respirator lung disease. In contrast, IR calcitonin-staining cells did not appear until late in the second trimester. They were present in small numbers from 20 weeks onward but were also most numerous in infants with chronic respirator lung disease. IR serotonin-staining cells were readily found in lungs of fetuses in the first trimester. By the second trimester many solitary neuroendocrine cells and neuroepithelial bodies staining for IR serotonin were present in developing terminal airways and a lesser number appeared in bronchioles and intrapulmonary bronchi. In premature infants, IR serotonin-staining cells were scarce in the presence of acute hyaline membrane disease but were numerous in lungs of infants with regenerating conducting airways associated with chronic respirator lung disease. IR Leu-enkephalin-staining cells were found only in one infant who survived 7 postnatal months of respirator care following neonatal hyaline membrane disease.     

Antioxidant gene expression in rat lung after exposure to cigarette smoke.

To investigate the effects of cigarette smoke on the expression of genes encoding intracellular antioxidant species, we exposed rats to whole cigarette smoke or air (control) daily for 1, 2, 7, or 14 days. After sacrifice, RNA was extracted from one lung and expression of mRNA for catalase (CAT), manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (CuZnSOD), glutathione peroxidase (GPX), and metallothionein (MT) was determined by Northern blots and dot blots. The anatomical distribution of expression of these genes was determined by in situ hybridization studies on sections of the contralateral lung. We found that expression of both MnSOD and MT was significantly increased (to levels 70 to 400% greater than in controls) at days 1 and 2 and returned to control levels by day 7. GPX expression was slightly but significantly increased at days 7 and 14 in smoke-exposed animals. CuZnSOD and CAT expression did not change from control levels. In control lungs, MnSOD was expressed in all cell types, with the highest expression seen in bronchial epithelial cells; a notable finding was a mosaic pattern of expression in the bronchial epithelium, with contiguous areas of bronchial epithelium composed of cells expressing MnSOD at high levels (hot spots), compared with the adjacent epithelium. In smoke-exposed lungs, the hot spots became less prominent after 1 and 2 days of exposure to smoke, but after 7 and 14 days the distribution of MnSOD expression was similar in control and smoke-exposed animals. CAT, CuZnSOD, GPX, and MT also showed widespread expression in the lung by in situ hybridization; GPX, CuZnSOD and MT were all most highly expressed in bronchial epithelium, whereas CAT expression levels were similar in all cell types. In contrast to MnSOD, expression of CAT, CuZnSOD, GPX, and MT was uniform within the bronchial epithelium, and the distribution of expression was the same in control and smoke-exposed animals at all time points. We conclude that most of these antioxidant enzymes and scavengers show prominent bronchial expression but that MnSOD shows a unique pattern, with intense hot spots in the epithelium of the small airways. This pattern is similar to the phenomenon of clonal heterogeneity described in other tissues but not previously reported in the lung. We conclude that cigarette smoke, like other forms of oxidant attack, transiently increases expression of MnSOD, and up-regulation of MnSOD expression appears to occur particularly in bronchial epithelial cells, which normally express MnSOD at relatively low levels. MT expression is also transiently increased by smoke whereas GPX expression increases after prolonged (7 to 14 days) exposure to cigarette smoke.     

Immunocytochemical localization of epidermal growth factor in the developing human respiratory system and in acute and chronic lung disease in the neonate

Cells staining for immunoreactive human epidermal growth factor were sought in the lungs and tracheas of human fetuses from 8 to 24 weeks of gestation. Lungs of liveborn infants from 25 to 40 weeks of gestation (stillborn to 7 months postnatal life), both with and without lung pathology, were also studied. In the early fetal trachea (12 to 15 weeks), many nonciliated cells immunostained for immunoreactive human epidermal growth factor in the lining epithelium. By 16 weeks of gestation this widespread staining was replaced by stained nonciliated single cells or small clusters of cells which were identifiable until 24 weeks. In the few tracheas which were available from liveborn infants who died without evidence of lung disease, stained cells were seldom identified in the lining epithelium after 24 weeks of gestation. In contrast, from 18 weeks until term, tracheal submucosal glands contained scattered cells which immunostained for immunoreactive human epidermal growth factor but which did not appear to be classical mucous cells. Beginning at 20 weeks of gestation, positively staining cells were found occasionally in bronchial lining epithelium, but more often in bronchial submucosal glands. Immunostained cells were never identified in bronchiolar epithelium in normal fetal or newborn lungs. In liveborn infants from 24 weeks onward who developed lung disease, many tracheas were severely damaged. In the presence of extensive denudation of the mucosa or the development of squamous metaplasia, immunostained cells were rarely seen in the lining epithelium. However, even under these conditions stained glandular cells could usually be identified. Stained cells were also present in the necks of those tracheal glands from which new epithelial lining cells appeared to be migrating onto denuded surfaces. Immunostained cells in the bronchial lining epithelium of infants with chronic lung disease were infrequent, just as they were in the fetus, but bronchial submucosal glands contained positively stained cells similar to those in tracheal glands. The appearance and distribution of immunostained cells were similar in the tracheal and bronchial submucosal glands in both normal subjects and those with all stages of lung disease. In contrast to the bronchioles of fetuses and infants without lung pathology, the bronchiolar epithelium of infants with chronic lung disease contained immunostained cells. Immunostained cells were found in areas of migrating dysplastic cells in relining conducting airways.(ABSTRACT TRUNCATED AT 400 WORDS)     

Induction of neutrophil chemoattractant cytokines by Mycoplasma hominis in alveolar type II cells.

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of premature infants who are mechanically ventilated due to respiratory distress. The disease consists of an initial inflammatory influx of neutrophils to the lungs, followed by long-term chronic fibrosis of the lung tissue. The antigenic repertoire that initiates the inflammatory component of BPD has not been defined. Furthermore, the repertoire of cytokines responsible for attracting neutrophils to the lung and the mediators of pathogenesis in BPD have not been characterized. Mycoplasmas such as Mycoplasma hominis and Ureaplasma urealyticum have been isolated from the lungs of infants that developed BPD and yet have not been widely recognized as potential initiators of the inflammatory component of BPD. In the studies described here, we examined the ability of both viable and heat-killed Mycoplasma hominis to elicit type II epithelial cell production of cytokines that are chemotactic for polymorphonuclear leukocytes (PMNs), particularly interleukin-8 (IL-8) and epithelial cell-derived neutrophil-activating peptide (ENA-78). The results of these studies demonstrate that M. hominis and M. hominis antigen are potent stimulators of type II epithelial cell-derived IL-8 and ENA-78. Thus, these data strongly suggest that the presence of M. hominis in the lungs of premature infants may initiate the inflammatory component of BPD by inducing epithelial cell production of cytokines chemotactic for PMNs. Furthermore, these data suggest that the onset of the inflammatory component of BPD likely precedes, and is independent of, the recruitment and activation of alveolar macrophages.     

Intracellular localization of the copper-zinc and manganese superoxide dismutases in rat liver parenchymal cells

Both the copper-zinc (CuZn) and the manganese (Mn) containing superoxide dismutases (SOD) have been immunolocalized in rat liver sections using protein A-gold labeling on ultrathin cryosections. The CuZnSOD was found to distribute uniformly throughout the nuclear and cytoplasmic matrix. The CuZn enzyme was excluded from membrane-bound compartments such as the nuclear envelope, endoplasmic reticulum, Golgi elements, secretory vesicles, and mitochondria. The primary exception was that lysosomes frequently labeled heavily for CuZnSOD. The lysosomal nature of these membrane-bound bodies was confirmed by double immunolabeling with a lysosomal enzyme, cathepsin-D. The MnSOD was located in mitochondria, particularly the matrix between the cristae. Light but distinct labeling for the MnSOD occurred in the cytoplasmic matrix.     

Surfactant-associated glycoproteins accumulate in alveolar cells and secretions during reparative stage of hyaline membrane disease

Surfactant-associated (SA) glycoproteins are lung-specific proteins produced in the human lung by alveolar type II cells and Clara cells. The distribution of these proteins was studied immunohistochemically in lung tissue obtained postmortem from 12 stillborn fetuses and 49 infants with hyaline membrane disease (HMD). By 21 weeks of gestation, SA glycoproteins were detected in the fetal alveolar epithelium and within Clara cells. The staining increased in intensity and extent with advancing gestational age. Infants with HMD who survived less than 48 hours did not generally exhibit stainable material either within type II cells or secretions, but staining was often noted in Clara cells as well as focally beneath hyaline membranes. In infants surviving more than 48 hours, intense staining of hyaline membranes, alveolar secretions, proliferating alveolar type II cells, and Clara cells was evident. Immunoreactivity was intense in hypertrophic type II cells that formed a continuous alveolar epithelial lining in lungs with bronchopulmonary dysplasia. Included in the population of infants with HMD were 15 infants with pulmonary hypoplasia. The lungs of these infants showed minimal staining for SA glycoproteins regardless of postnatal survival time. The results provide an immunomorphologic basis for defining normal and abnormal lung maturation. They also indicate that enhanced SA glycoprotein production is a sustained response of regenerating and hypertrophic type II cells in premature infants.     

Altered expression of cyclins and cdks in premature infant baboon model of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of premature infants, which results in substantial morbidity. The pathophysiology of BPD includes oxidant injury, baro/volutrauma, and disordered lung repair. As lung development, differentiation, and repair require cell division, we hypothesized dysregulation of the cell cycle in oxygen exposure of premature infants that may contribute to the evolution of BPD. In this investigation, we studied the expression of cyclins and cyclin-dependent kinases (cdks) that regulate transition from G1 and G2 phases of the cell cycle. We report here that expression of cyclin D1, cyclin E, and cyclin A is modulated in premature baboons in respiratory distress. In addition, the expression of cdk1 or cdk4 was also modulated in these premature animals. The phosphorylation of retinoblastoma protein was progressively decreased in 125-day animals and in 140-day animals exposed to 6 or 14 days of PRN oxygen. These results indicate that due to altered cyclin and cdk expression, the repair of injured epithelium may proceed in a disordered manner that is characteristic of BPD. Thus, altered cell cycle regulation may be an important factor in the evolution of BPD.     

Immunohistochemical study of human pulmonary surfactant apoproteins with monoclonal antibodies. Pathologic application for hyaline membrane disease.

Three monoclonal antibodies, PC6, PE10, and PE12, were used for immunohistochemical studies of human lungs by immunoperoxidase staining. Monoclonal antibodies PC6 and PE10 against pulmonary surfactant apoproteins stained faint granules in the cytoplasm of some alveolar wall cells in adult lung. These stained cells appeared to be alveolar Type II cells. A fetal lung of 20 weeks' gestation had no any positive staining. However, a few scattered positive cells were observed in a newborn lung of 31 weeks' gestation, and the stained cells increased progressively with increasing gestational age. The positively stained cells were very few in the lungs of newborns who died of respiratory distress syndrome (RDS), but the lungs of newborns who died of other causes after recovery from RDS showed many positively stained cells. These results suggest that the immunohistochemical demonstration of the monoclonal antibodies PC6 and PE10 could be a good pathodiagnostic indicator reflecting the localization and development of pulmonary surfactant by alveolar Type II cells. On the other hand, monoclonal antibody PE12 was found to recognize the antigen that occurs on the surfaces of the alveoli of fetal, newborn, and adult lungs as one component of the alveolar lining layer, different from pulmonary surfactant.     

Age-related changes in antioxidant enzymes and lipid peroxidation in brains of control and transgenic mice overexpressing copper-zinc superoxide dismutase

The aim of our study was first to obtain a comprehensive profile of the brain antioxidant defense potential and peroxidative damage during aging. We investigated copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD), seleno-dependent glutathione peroxidase (GSH-PX), glutathione reductase (GSSG-R) activities, endogenous and in vitro stimulated lipid perxidation in 40 brains of control mice divided into 3 age groups: 2 months (young), 12 months (middle-aged) and 28 months (old). We found a positive correlation between age and activities of CuZnSOD (r = 0.47); P < 0.01) and GSH-PX (r = 0.72; P < 0.0001). CuZnSOD and GSH-PX activities are independently regulated during brain aging since temporal changes of these two enzymes do not correlate. No modification in MnSOD activity and basal lipid peroxidation was observed as a function of age. Nevertheless, stimulated lipid peroxidation was significantly higher at 12 months (6.53 ± 0.71 μmole MDA/g tissue) thatn at 2 months (5.69 ± 0.90) and significantly lower than 28 months (5.13 ± 0.33) than at 12 months.Second, we used genetic manipulations to construct transgenic mice that specifically overexpress CuZnSOD to understand the role of CuZnSOD in neuronal aging. The human CuZnSOD transgene expression was stable during aging. The increased CuZnSOD activity in the brain (1.9-fold) of transgenic mice resulted in an enhanced rate of basal lipid peroxidation and in increased MnSOD activity in the 3 age groups. Other antioxidant enzymes did not exhibit modifications indicating the independence of the regulation between CuZnSOD and glutathione-related enzymes probably due to their different cellular localization in the brain.     

Glycogen accumulations in differentiating mesonephric ducts and tubuli in male human embryos

Human mesonephric duct epithelial cells contained empty appearing regions in the infranuclear cytoplasm when prepared for transmission electron microscopy using glutaraldehyde and osmium fixation. The same regions stained positively with PAS in Epon sections for light microscopy suggesting that glycogen was present. Incubation with saliva abolished the reaction. For electron microscopy the glycogen stained very intensely if a mixture of osmium tetroxide and potassium ferrocyanide was used instead of osmium alone. Glycogen accumulations were present between the ages of 5 to 10 weeks and absent at the age of 15 weeks. Reports by others indicate that glycogen may be present in different reactive forms in relation to its staining behaviour after various fixatives. The present results, and similar studies in other tissues, indicate that osmium tetroxide-potassium ferrocyanide fixative should be used routinely for preservation of embryos and fetuses and where indicated, for ultrastructural identification of glycogen and cytoplasmic filaments in clinical specimens.     

Immunohistochemical localization of glutathione-S-transferase and glutathione peroxidase in adult Syrian hamster tissues and during kidney development.

Tissues from adult Syrian hamsters were studied with immunoperoxidase techniques using polyclonal antibodies to glutathione-S-transferase (rat liver and human placental enzymes) and human erythrocyte glutathione peroxidase. Most tissues immunostained similarly with these antibodies. Most notable was the cytoplasmic staining of mesenchyme tissues, especially smooth muscle, by all three antibodies. Epithelial cells stained distinctively, but usually less intensely than mesenchyme. Epithelial cells from all levels of the gastrointestinal tract, respiratory epithelium, transitional epithelium, and epidermis all showed strong staining with these antibodies. Other epithelial cell types were usually positive but showed less dramatic staining. Most epithelial tissues showed both nuclear and cytoplasmic staining; some also showed cell-surface (eg, cilia) staining. The role of these enzymes in cell differentiation of a stable organ was studied by immunostaining the kidney during its development. Early stroma (13- and 15-day fetuses) of the kidney (metanephric mesenchyme) showed strong cell-surface staining for glutathione transferases and moderate staining for glutathione peroxidase; renal tubules (which are epithelial cells) at this stage were negative for these markers. As renal tubules differentiated, first cytoplasm and then nuclei stained moderately, suggesting that glutathione-S-transferases and glutathione peroxidase are markers of both mesenchymal cells, including embryonic mesenchyme, and terminal differentiation of at least some epithelial cells.     

IL-1beta disrupts postnatal lung morphogenesis in the mouse

Pulmonary inflammation and increased production of the inflammatory cytokine IL-1beta are associated with the development of bronchopulmonary dysplasia (BPD) in premature infants. To study the actions of IL-1beta in the fetal and newborn lung in vivo, we developed a bitransgenic mouse in which IL-1beta is expressed under conditional control in airway epithelial cells. Perinatal pulmonary expression of IL-1beta caused respiratory insufficiency that was associated with increased postnatal mortality. While intrauterine growth of IL-1beta-expressing mice was normal, their postnatal growth was impaired. IL-1beta disrupted alveolar septation and caused abnormalities in alpha-smooth muscle actin and elastin deposition in the septa of distal airspaces. IL-1beta disturbed capillary development and inhibited the production of vascular endothelial growth factor in the lungs of infant mice. IL-1beta induced the expression of CXC chemokines KC (CXCL1) and macrophage inflammatory protein-2 (CXCL2) and of CC chemokines monocyte chemotactic protein (MCP)-1 (CCL2) and MCP-3 (CCL7), consistent with neutrophilic and monocytic infiltration of the lungs. IL-1beta caused goblet cell metaplasia and bronchial smooth muscle hyperplasia. Perinatal expression of IL-1beta in epithelial cells of the lung caused a lung disease that was clinically and histologically similar to BPD.     

Oxidative stress and overexpression of manganese superoxide dismutase in patients with Alzheimer''s disease

Substantial evidence supports the hypothesis that oxygen free radicals are involved in various neurodegenerative disorders. To assess the presence of oxidative stress in Alzheimer's disease (AD) we examined the activity of the enzyme copper-zinc superoxide dismutase (CuZnSOD) in red blood cells, the levels of the mitochondrial inducible enzyme manganese superoxide dismutase (MnSOD) mRNA in lymphocytes, and the total radical-trapping antioxidant capacity (TRAP) in plasma of AD patients and in a group of age-matched non-demented controls. We found that CuZnSOD activity (P<0.01 vs. controls) was significantly increased as well as the MnSOD mRNA levels while the total antioxidant status (P<0.001 vs. controls) was decreased in AD patients. These findings support the role of oxidative alterations in the pathogenetic mechanism underlying AD neurodegeneration.     

Hassall's corpuscles in the thymus of fetuses, infants and children: immunological and histochemical aspects

Hassall's corpuscles (HC) were examined for immunological and histochemical markers in cryostat sections of thymus from fetuses, infants and children. HC could not be detected before 14 weeks of gestation. Receptors for the Fc part of IgG (Fc gamma R) were demonstrated by adherence of ox erythrocytes sensitized with anti-ox IgG using a closed chamber technique. Fc gamma R were also detected by immune complexes of horseradish peroxidase (HRP) and rabbit antibodies to HRP, and with an anti-Fc gamma R serum, using indirect immunofluorescence technique and indirect immunoperoxidase technique. The staining was seen along the outer cell membranes of the HC. The Fc gamma R activity was highest in early fetal life, and decreased with increasing age. Indicator cells which detect receptors for the Fc part of IgM and for the activated third component of complement did not adhere to HC. At 14 weeks of gestation, HC showed a weak alpha-naphthyl acetate esterase (ANAE) activity, while from 16 weeks the staining intensity and pattern was unchanged. In some HC, separate cells with strong ANAE activity were seen. These cells also showed endogenous peroxidase activity, and were stained by an antibody to HLA-DR antigens. Such cells were not seen until 16 weeks of gestation. HC were stained by antibodies to IgG in fetuses older than 16 weeks, and the intensity increased gradually up to 24 weeks. Antibodies to IgM weakly stained some HC in fetuses between 16 and 36 weeks of gestation, whereas antibodies to IgA stained a minority of HC in fetuses older than 24 weeks.     

Sleep Deprivation Alters Gene Expression and Antioxidant Enzyme Activity in Mice Splenocytes

Cellular defence against the formation of reactive oxygen species (ROS) involves a number of mechanisms in which antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD) play an important role. The relation between sleep deprivation and oxidative stress has not yet been completely elucidated. Although some authors did not find evidence of this relationship, others found alterations in some oxidative stress markers in response to sleep deprivation. Thus, the objective of this study was to identify changes induced by sleep deprivation in the activity and gene expression of antioxidant enzymes in mice splenocytes, ideally corroborating a better understanding of the observed effects related to sleep deprivation, which could be triggered by oxidative imbalance. Splenocytes from mice sleep deprived for 72 h showed no significant difference in CAT and CuZnSOD gene expression compared with normal sleep mice. However, sleep‐deprived mice did show higher MnSOD gene expression than the control group. Concerning enzymatic activity, CuZnSOD and MnSOD significantly increased after sleep deprivation, despite the expression in CuZnSOD remained unchanged. Moreover, CAT activity was significantly lower after sleep deprivation. The data suggest that the antioxidant system is triggered by sleep deprivation, which in turn could influence the splenocytes homoeostasis, thus interfering in physiological responses.     

Antioxidant Enzyme Expression in Clinical Isolates of Pseudomonas aeruginosa: Identification of an Atypical Form of Manganese Superoxide Dismutase

Expression of superoxide dismutases (FeSOD and MnSOD) and catalases by laboratory strains of Pseudomonas aeruginosa is modulated by exogenous factors. Whether clinical isolates behave similarly and whether antioxidant enzyme expression influences P. aeruginosa virulence remain unclear. Fifty-seven P. aeruginosa blood culture isolates, plus seven pairs of blood and local-site isolates, were examined for FeSOD, MnSOD, and catalase production in vitro. Under iron-replete growth conditions FeSOD and catalase activities were maximized. MnSOD was not detected. FeSOD and catalase activity decreased under iron-limited growth conditions, whereas MnSOD activity appeared. SOD and catalase activity did not change with site of isolation or by patient. MnSOD could not be expressed by one isolate due to a missense mutation in sodA that produced a premature stop codon. Eleven percent of the isolates expressed a novel, rapidly migrating MnSOD that was associated with missense mutations in the normal stop codon of sodA. We conclude that clinical P. aeruginosa isolates vary little in FeSOD and catalase expression. Some strains produce a newly described MnSOD variant, whereas one is deficient in MnSOD production. The absence of MnSOD expression in a P. aeruginosa strain causing invasive human disease indicates that MnSOD is probably not essential for P. aeruginosa virulence.