Prolonged postoperative cognitive dysfunction (POCD) is reported to occur frequently after cardiac surgery. However, it is rarely assessed in routine clinical practice and receives little attention. ...Although the cerebral consequences of cardiopulmonary bypass have been measured clinically, insights into the resulting molecular and pathologic events within the brain have only begun to be investigated. POCD is likely to impair quality of life and constitutes a large burden on society when elderly patients prematurely lose their independence. Numerous studies have reported that neurocognitive deficit is associated with heightened mortality, increased length of hospital stay, and discharge to a nursing home. This is linked with a tremendous demand for health-care resources. Because of the magnitude of the clinical problem, serious consideration must be directed toward understanding its etiology and the development of neuroprotective strategies. Clearly identifying the mechanisms of POCD is challenging. The purpose of this review is to discuss recent developments in our understanding of the pathophysiologic mechanisms, prevention, and treatments that have been designed to ameliorate brain dysfunction after cardiac surgery.
Background: In atopic dermatitis (AD) there is evidence of tissue fibrosis involving a number of structural changes, including papillary dermal fibrosis and epidermal hyperplasia. These changes are ...suggested to be the result of chronic inflammation of the skin. Several remodeling-associated cytokines, including transforming growth factor (TGF) β1, IL-11, and IL-17, have been shown to be increased in allergic diseases, including asthma. Objective: We investigated TGF-β1, IL-11, and IL-17 expression in skin biopsy specimens recovered from acute and chronic skin lesions from patients with AD, as well as from uninvolved skin of patients with AD and skin from healthy volunteers. We also examined the correlation between the expression of these cytokines and the extent of total, type I, and type III collagen deposition. Methods: We evaluated the expression of TGF-β1, IL-11, and IL-17 by means of immunohistochemistry. Collagen deposition was assessed by means of immunohistochemistry and van Gieson staining. Results: TGF-β1 expression was markedly enhanced in both acute and particularly chronic lesions (
P < .001). Although IL-11 expression was significantly increased only in chronic lesions (
P < .0001), IL-17 was preferentially associated with acute lesions (
P < .005). Although collagen type III deposition was not significantly different among the groups, type I collagen deposition was significantly increased in chronic AD lesions (
P < .0005). There was a significant correlation between IL-11 and type I collagen deposition, as well as the number of eosinophils in skin specimens from patients with AD (
r
2 = 0.527, and
r
2 = 0.622, respectively;
P < .0001). Conclusion: These results suggest that TGF-β1, IL-11, and IL-17 are involved in the remodeling of skin lesions in patients with AD. However, IL-11 and IL-17 are preferentially expressed at different stages of the disease. Type I collagen appeared to be the major subtype involved in this repair process.
Although mitochondrial dysfunction and oxidative stress are central mechanisms in various pathological conditions, they have not been extensively studied in the gastrointestinal tract, which is known ...to be constantly exposed to luminal oxidants from ingested foods. Key among these is the simultaneous consumption of iron salts and ascorbic acid, which can cause oxidative damage to biomolecules.
The objective of the present work was to evaluate how iron-ascorbate (FE/ASC)-mediated lipid peroxidation affects mitochondrion functioning in Caco-2/15 cells. Our results show that treatment of Caco-2/15 cells with FE/ASC (0.2 mM/2 mM) (1) increased malondialdehyde levels assessed by HPLC; (2) reduced ATP production noted by luminescence assay; (3) provoked dysregulation of mitochondrial calcium homeostasis as evidenced by confocal fluorescence microscopy; (4) upregulated the protein expression of cytochrome C and apoptotic inducing factor, indicating exaggerated apoptosis; (5) affected mitochondrial respiratory chain complexes I, II, III and IV; (6) elicited mtDNA lesions as illustrated by the raised levels of 8-OHdG; (7) lowered DNA glycosylase, one of the first lines of defense against 8-OHdG mutagenicity; and (8) altered the gene expression and protein mass of mitochondrial transcription factors (mtTFA, mtTFB1, mtTFB2) without any effects on RNA Polymerase. The presence of the powerful antioxidant BHT (50 microM) prevented the occurrence of oxidative stress and most of the mitochondrial abnormalities.
Collectively, our findings indicate that acute exposure of Caco-2/15 cells to FE/ASC-catalyzed peroxidation produces harmful effects on mitochondrial functions and DNA integrity, which are abrogated by the powerful exogenous BHT antioxidant. Functional derangements of mitochondria may have implications in oxidative stress-related disorders such as inflammatory bowel diseases.
Recruitment of activated T cells to mucosal surfaces, such as the airway epithelium, is important in host defense and for the development of inflammatory diseases at these sites. We therefore asked ...whether the CXC chemokines IFN-induced protein of 10 kDa (IP-10), monokine induced by IFN-gamma (Mig), and IFN-inducible T-cell alpha-chemoattractant (I-TAC), which specifically chemoattract activated T cells by signaling through the chemokine receptor CXCR3, were inducible in respiratory epithelial cells. The effects of proinflammatory cytokines, including IFN-gamma (Th1-type cytokine), Th2-type cytokines (IL-4, IL-10, and IL-13), and dexamethasone were studied in normal human bronchial epithelial cells (NHBEC) and in two human respiratory epithelial cell lines, A549 and BEAS-2B. We found that IFN-gamma, but not TNF-alpha or IL-1 beta, strongly induced IP-10, Mig, and I-TAC mRNA accumulation mainly in NHBEC and that TNF-alpha and IL-1 beta synergized with IFN-gamma induction in all three cell types. High levels of IP-10 protein (> 800 ng/ml) were detected in supernatants of IFN-gamma/TNF-alpha-stimulated NHBEC. Neither dexamethasone nor Th2 cytokines modulated IP-10, Mig, or I-TAC expression. Since IFN-gamma is up-regulated in tuberculosis (TB), using in situ hybridization we studied the expression of IP-10 in the airways of TB patients and found that IP-10 mRNA was expressed in the bronchial epithelium. In addition, IP-10-positive cells obtained by bronchoalveolar lavage were significantly increased in TB patients compared with normal controls. These results show that activated bronchial epithelium is an important source of IP-10, Mig, and I-TAC, which may, in pulmonary diseases such as TB (in which IFN-gamma is highly expressed) play an important role in the recruitment of activated T cells.
Increased extracellular matrix (ECM) deposition in the airway wall contributes to the airway wall remodeling observed in asthmatics. Although alterations in collagen have been well described, less is ...known about changes in other components of the ECM, particularly proteoglycans (PGs). Endobronchial biopsies were obtained from seven patients with mild atopic asthma and six normal control subjects. Tissues were blocked in OCT and frozen in isopentane. Sections were immunostained with antibodies for the small leucine-rich PGs, lumican, biglycan, decorin, and fibromodulin and for versican, a large chondroitin sulfate PG. We calculated the area of positive staining in the subepithelial layer, correcting for basement membrane length. Lumican, biglycan, and versican were localized predominantly in the subepithelial layer of the airway wall in all groups. PG deposition was significantly increased in asthmatics as compared with that in control subjects. Furthermore, the degree of PG immunoreactivity was significantly correlated with airway responsiveness in the asthmatics (lumican; r = -0.77, p < 0.05; biglycan: r = -0.76, p < 0.05; versican: r = -0.74, p = 0.06). Our results suggest that PGs may play a role in airway wall remodeling and thereby, airway mechanics in asthma.
Induced sputum from asthmatic patients has been recently used to assess inflammatory cells. We have previously reported an increased expression of Th-2–type cytokines in induced sputum of asthmatic ...patients. C-C chemokines, particularly eotaxin and monocyte chemotactic protein (MCP)-4, are associated with eosinophilic infiltration. Interleukin (IL)-16 is associated with chemotactic activity for CD4+ cells. Chemokine expression in BAL and bronchial biopsy specimens has been demonstrated in asthmatic airways, but not in induced sputum.
We examined whether eotaxin, MCP-4, and IL-16 expression could be detected in induced sputum of asthmatic patients (n = 10), and whether the expression was increased compared to normal control subjects (n = 9). Eotaxin, MCP-4, and IL-16 immunoreactivity were determined by immunocytochemistry. In addition, inflammatory cells were investigated using markers for T cells (CD3), eosinophils (major basic proteinMBP), macrophages (CD68), neutrophils (elastase), and epithelial cells (cytokeratin).
Our results showed that there was a significant difference in the percentages of MBP-positive and epithelial cells between asthmatic patients and normal control subjects (p < 0.05). However, there was no difference between these two groups in the percentage of CD3-, elastase-, and CD68-positive cells. Immunoreactivity for eotaxin, MCP-4, and IL-16 was expressed in the induced sputum of all asthmatic patients, and expression of these chemotactic cytokines was significantly greater than in control subjects (p < 0.001, p < 0.005, and p < 0.001, respectively).
This study showed that induced sputum could be used to detect chemokines in patients with bronchial asthma, and that the upregulation of chemotactic cytokines in the airways can be seen using noninvasive techniques.
Background: IL-15 is a TH1-related cytokine that shares many biologic activities with IL-2. Both cytokines bind a specific α subunit, and they share the same β and γ common receptor subunits for ...signal transduction. IL-15 has recently been shown to be upregulated in T cell–mediated inflammatory disorders, such as rheumatoid arthritis and inflammatory bowel diseases. However, the role and expression of IL-15 in inflammatory lung disease has not been investigated. Objective: In the present study we have evaluated the expression of IL-15 mRNA and protein in bronchial biopsy specimens obtained from patients with sarcoidosis (n = 8), tuberculosis (n = 7), chronic bronchitis (n = 10), and bronchial asthma (n = 8) and compared its expression with that seen in normal control subjects (n = 11). Methods: In situ hybridization and immunocytochemistry were used to detect the number of cells expressing IL-15 mRNA and protein, respectively, within sections of bronchial tissues from all subject groups. In addition, double immunocytochemistry was used to characterize the cellular source of IL-15. Results: The number of IL-15+ cells was significantly higher within tissue from patients with sarcoidosis, tuberculosis, and chronic bronchitis compared with that in asthmatic patients and normal control subjects. Similar results were obtained for IL-15 immunoreactivity by using immunohistochemistry. Furthermore, double immunostaining revealed that neutrophils and macrophages are the major source of IL-15. Conclusion: These results suggest that the expression of IL-15 may be associated with TH1-mediated chronic inflammatory diseases of the lung. (J Allergy Clin Immunol 2001;108:970-5.)
Cardiopulmonary bypass (CPB), a procedure often used during cardiac surgery, is associated with an inflammatory process that leads to lung injury. We hypothesized that inhaled nitric oxide (INO), ...which has anti-inflammatory properties, possesses the ability to modulate lung cell apoptosis and prevent CPB-induced inflammation.
Twenty male pigs were randomly classified into four groups: sham, sham plus INO, CPB, and CPB plus INO. INO (20 ppm) was administered for 24 h after anesthesia. CPB was performed 90 min into INO treatment. BAL fluid and blood were collected at time 0 (before CPB), at 4 h after beginning CPB, and 24 h after beginning CPB (T24).
At T24, BAL interleukin (IL)-8 levels and neutrophil percentages were elevated significantly in the CPB group. At T24, INO reduced IL-8 concentrations and attenuated the increase of neutrophil percentage in the CPB-plus-INO group. Nitrite-plus-nitrate (NOx) concentrations were decreased significantly in groups without INO. Moreover, animals treated with INO showed higher rates of pulmonary apoptosis compared to their respective control groups except for the sham-plus-INO group, in which they were diminished.
These results demonstrate that NOx production is reduced after CPB, and that INO acts as an anti-inflammatory agent by decreasing neutrophil numbers and their major chemoattractant, IL-8. INO also increases cell apoptosis in the lungs during inflammatory conditions, which may explain, in part, how it resolves pulmonary inflammation.
Background: High expression of IL-5 by T cells in the airways of asthmatic individuals is believed to play a fundamental role in the eosinophilia associated with this disease. Recently, the ...transcription factor GATA-3 was shown to be critical for IL-5 gene expression in T
H2 cells in vitro.
Objective: Our aim was to examine the expression of GATA-3 mRNA and its colocalization within the airways of asthmatic and nonasthmatic individuals.
Methods: We investigated the association between GATA-3 gene expression, airway inflammatory cells, and IL-5 gene expression in bronchoalveolar lavage fluid and bronchial biopsy specimens from atopic asthmatic subjects (n = 10) and normal control subjects (n = 10).
Results: We report that GATA-3 mRNA expression is significantly increased in the airways of asthmatic subjects compared with those of normal control subjects (
P < .001). Numbers of cells expressing GATA-3 transcripts correlated significantly with reduced airway caliber (
P < .05) and airways hyperresponsiveness (
P < .05) in asthmatic subjects. Colocalization studies showed that the majority (approximately 60% to 90%) of GATA-3 mRNA
+ cells in asthmatic airways were CD3
+ T cells, with smaller contributions from major basic protein
+ eosinophils and tryptase
+ mast cells. The density of GATA-3 mRNA
+ cells correlated significantly with the numbers of cells expressing IL-5 mRNA (
P < .001,
r = 0.879 for bronchoalveolar lavage fluid;
P < .05,
r = 0.721 for biopsy specimens). Furthermore, double in situ hybridization demonstrated that approximately 76% of GATA-3 mRNA
+ cells coexpressed IL-5 mRNA and that 91% of IL-5 mRNA
+ cells coexpressed GATA-3 mRNA.
Conclusion: The results of this study provide the first evidence of increased GATA-3 gene expression in association with IL-5 mRNA
+ cells in asthmatic airways. These findings support a causal association between augmented GATA-3 expression and dysregulated IL-5 expression in atopic asthma. (J Allergy Clin Immunol 1999;103:215-22.)
Background: It is well-known that the expression of T helper (Th) type 2 cytokines such as interleukin (IL)-4 and IL-5, and their receptors,
is up-regulated within the airways of allergic asthmatic ...patients. Furthermore, higher numbers of cells producing GATA-3,
c-MAF, and signal transducer and activator of transcription factor (STAT)-6, which are transcription factors (TFs) that are
implicated in the regulation and signaling of the Th2 cytokines, have been observed in bronchial biopsy specimens from asthmatic
patients but not in those of healthy control subjects.
Methods: We examined whether these mediators also can be detected in induced sputum. Immunoreactivity for IL-4Rα, IL-5Rα, GATA-3,
c-MAF, and STAT-6 was investigated in samples of induced sputum from asthmatic patients (n = 8) and healthy control subjects
(n = 8).
Results: Our results showed that the numbers of cells expressing IL-4 receptor α (Rα) and IL-5Rα were higher in samples from asthmatic
patients compared to those of control subjects (p < 0.01). More cells exhibiting GATA-3, c-MAF, and STAT-6 immunoreactivity
also were found in asthmatic patients vs those in control subjects (p < 0.005). Furthermore, the expression of STAT-6 and
IL-4Rα, GATA-3 and IL-5Rα, and c-MAF with both IL-4Rα and IL-5Rα was correlated (p < 0.05).
Conclusions: This study demonstrated that induced sputum provides sufficient sensitivity for examining the pathways of cytokine signaling,
cytokine receptor signaling, and intracellular signaling. Furthermore, these data show correlations between the expression
of Th2 cytokine receptors and associated TFs in the human lung, which has not been documented previously.
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