4-Hydroxynonenal modifies IgA in rat intestine after lipopolysaccharide injection

Increased plasma glutamate in non-smokers with vasospastic angina pectoris is associated with plasma cystine and antioxidant capacity

Objectives. Endothelial dysfunction caused by oxidative stress plays an important role in the development of vasospastic angina pectoris (VSAP). Glutamate causes endothelial dysfunction by generating oxidative stress, and it inhibits cystine import into endothelial cells via the cystine/glutamate antiporter (X_C^-), which leads to depletion of antioxidant glutathione. However, whether glutamate and cystine are implicated in the pathogenesis of VSAP remains unclear. We investigated plasma glutamate and cystine levels, oxidative stress markers and antioxidant capacity in non-smoker patients with VSAP to determine whether glutamate and cystine are associated with the development of VSAP. We assessed 49 non-smokers assigned to groups with (n = 27) and without (n = 22) VSAP, and also measured plasma glutamate, cystine, nitrotyrosine, reactive oxygen metabolites and biological antioxidant potential. Results. Plasma glutamate and cystine values were significantly higher in the group with, than without VSAP (59.8 ± 25.7 vs. 43.5 ± 18.7 µmol/L, p = .016 and 35.3 ± 14.2 vs. 25.2 ± 9.1 µmol/L, p = .0056, respectively). Plasma glutamate and cystine values were significantly and positively associated (r = 0.32, p = .027). Levels of the oxidative stress markers nitrotyrosine and reactive oxygen metabolites, and biological antioxidant potential of as a measure of antioxidant capacity, did not significantly differ between the two groups. However, glutamate and biological antioxidant potential values were significantly and negatively associated (r = -0.3, p = .036). Conclusion. Plasma glutamate levels were increased in patients with VSAP who did not smoke, and they were positively associated with plasma cystine and negatively associated with the biological antioxidant potential levels.

Lipopolysaccharide impairs mucin secretion and stimulated mucosal immune stress response in respiratory tract of neonatal chicks

The chicken immune system is immature at the time of hatching. The development of the respiratory immune system after hatching is vital to young chicks. The aim of this study was to investigate the effect of LPS on respiratory mucin and IgA production in chicks. In this study, we selected 7days old AA broilers of similar weigh randomly; LPS atomized at 1mg/kg body weigh dose in the confined space of 1 cubic meter. The chickens exposed for 2h. Then collect samples after 4h and 8h respectively. Compared to control, LPS inhibited mucus production in BALF, caused a rising trend of the concentration of IgA in serum and BALF, and increased the protein expression of IgA in lung tissue. And LPS treat induced a decreasing trend of the mRNA expression of IL-6 and TGF-β and significantly decreased the gene expression of TGF-α and EGFR after 4h. After 8h the LPS suppressed the TGF-β mRNA expression significantly. In addition, LPS treatment stimulated airway epithelial cilia sparse after 4h. Therefore, results proved: LPS can impair mucin expression and stimulated mucosal immune stress reaction of respiratory tract. This study suggested that LPS involved in respiratory tract mucosal immune response in chicks by regulating gene expression of cytokines and epithelial growth factors.

Contribution of the HNE-immunohistochemistry to modern pathological concepts of major human diseases

Excessive production of reactive oxygen species can induce peroxidation of the polyunsaturated fatty acids thus generating reactive aldehydes like 4-hydroxy-2-nonenal (HNE), denoted as "the second messenger of free radicals". Because HNE has high binding affinity for cysteine, histidine and lysine it forms relatively stable and hardly metabolized protein adducts. By changing structure and function of diverse structural and regulatory proteins, HNE achieves not only cytotoxic, but also regulatory functions in various pathophysiological processes. Numerous animal model studies and clinical trials confirmed HNE as one of the crucial factors in development and progression of many disorders, in particular of cancer, (neuro)degenerative, metabolic and inflammatory diseases. Since HNE has multiple biological effects and is in the living system usually bound to proteins and peptides, many research groups work on development of specific immunochemical methods targeting the HNE-histidine adducts as major bioactive marker of lipid peroxidation, following the research pathway initiated by Hermann Esterbauer, who discovered HNE in 60's. Such immunohistochemical studies did not only prove the high biomedical importance of HNE, but have also given new insights into major diseases of the modern man. Immunohistochemical studies have shown reversibility of formation of the HNE-protein adducts, as well as differential onset of the HNE-mediated lipid peroxidation between age- associated atherosclerosis and photoaging, revealing eventually selective anti-cancer effects of HNE produced by non-malignant cells in vicinity of cancer. This review summarizes some of the HNE-histidine immunohistochemistry findings we believe are of broad biomedical interest and could inspire new studies in the field.

HNE and cholesterol oxidation products in colorectal inflammation and carcinogenesis

Consistent experimental data suggest the importance of inflammation-associated oxidative stress in colorectal cancer (CRC) pathogenesis. Inflammatory bowel disease with chronic intestinal inflammation is now considered a precancerous condition. Oxidative stress is an essential feature of inflammation. Activation of redox-sensitive pro-inflammatory cell signals and inflammatory mediators concur to establish a pro-tumoral environment. In this frame, lipid oxidation products, namely 4-hydroxynonenal and oxysterols, can be produced in big quantity so as to be able to exert their function as inducers of cell signaling pathways of proliferation and survival. Notably, an important source of these two compounds is represented by a high fat diet, which is undoubtedly a risk factor for inflammation and CRC development. Current evidence for the emerging implication of these two oxidized lipids in inflammation and CRC development is discussed in this review.

Redox signaling in the gastrointestinal tract

Redox signaling regulates physiological self-renewal, proliferation, migration and differentiation in gastrointestinal epithelium by modulating Wnt/β-catenin and Notch signaling pathways mainly through NADPH oxidases (NOXs). In the intestine, intracellular and extracellular thiol redox status modulates the proliferative potential of epithelial cells. Furthermore, commensal bacteria contribute to intestine epithelial homeostasis through NOX1- and dual oxidase 2-derived reactive oxygen species (ROS). The loss of redox homeostasis is involved in the pathogenesis and development of a wide diversity of gastrointestinal disorders, such as Barrett's esophagus, esophageal adenocarcinoma, peptic ulcer, gastric cancer, ischemic intestinal injury, celiac disease, inflammatory bowel disease and colorectal cancer. The overproduction of superoxide anion together with inactivation of superoxide dismutase are involved in the pathogenesis of Barrett's esophagus and its transformation to adenocarcinoma. In Helicobacter pylori-induced peptic ulcer, oxidative stress derived from the leukocyte infiltrate and NOX1 aggravates mucosal damage, especially in HspB+ strains that downregulate Nrf2. In celiac disease, oxidative stress mediates most of the cytotoxic effects induced by gluten peptides and increases transglutaminase levels, whereas nitrosative stress contributes to the impairment of tight junctions. Progression of inflammatory bowel disease relies on the balance between pro-inflammatory redox-sensitive pathways, such as NLRP3 inflammasome and NF-κB, and the adaptive up-regulation of Mn superoxide dismutase and glutathione peroxidase 2. In colorectal cancer, redox signaling exhibits two Janus faces: On the one hand, NOX1 up-regulation and derived hydrogen peroxide enhance Wnt/β-catenin and Notch proliferating pathways; on the other hand, ROS may disrupt tumor progression through different pro-apoptotic mechanisms. In conclusion, redox signaling plays a critical role in the physiology and pathophysiology of gastrointestinal tract.

Inflammatory bowel disease: mechanisms, redox considerations, and therapeutic targets

Oxidative stress is thought to play a key role in the development of intestinal damage in inflammatory bowel disease (IBD), because of its primary involvement in intestinal cells' aberrant immune and inflammatory responses to dietary antigens and to the commensal bacteria. During the active disease phase, activated leukocytes generate not only a wide spectrum of pro-inflammatory cytokines, but also excess oxidative reactions, which markedly alter the redox equilibrium within the gut mucosa, and maintain inflammation by inducing redox-sensitive signaling pathways and transcription factors. Moreover, several inflammatory molecules generate further oxidation products, leading to a self-sustaining and auto-amplifying vicious circle, which eventually impairs the gut barrier. The current treatment of IBD consists of long-term conventional anti-inflammatory therapy and often leads to drug refractoriness or intolerance, limiting patients' quality of life. Immune modulators or anti-tumor necrosis factor α antibodies have recently been used, but all carry the risk of significant side effects and a poor treatment response. Recent developments in molecular medicine point to the possibility of treating the oxidative stress associated with IBD, by designing a proper supplementation of specific lipids to induce local production of anti-inflammatory derivatives, as well as by developing biological therapies that target selective molecules (i.e., nuclear factor-κB, NADPH oxidase, prohibitins, or inflammasomes) involved in redox signaling. The clinical significance of oxidative stress in IBD is now becoming clear, and may soon lead to important new therapeutic options to lessen intestinal damage in this disease.

Transient receptor potential ankyrin 1 is expressed by inhibitory motoneurons of the mouse intestine

BACKGROUND & AIMS

Transient receptor potential ankyrin (TRPA) 1, an excitatory ion channel expressed by sensory neurons, mediates somatic and visceral pain in response to direct activation or noxious mechanical stimulation. Although the intestine is routinely exposed to irritant alimentary compounds and inflammatory mediators that activate TRPA1, there is no direct evidence for functional TRPA1 receptors on enteric neurons, and the effects of TRPA1 activation on intestinal function have not been determined. We characterized expression of TRPA1 by enteric neurons and determined its involvement in the control of intestinal contractility and transit.

METHODS

TRPA1 expression was characterized by reverse-transcription polymerase chain reaction and immunofluorescence analyses. TRPA1 function was examined by Ca(2+) imaging and by assays of contractile activity and transit.

RESULTS

We detected TRPA1 messenger RNA in the mouse intestine and TRPA1 immunoreactivity in enteric neurons. The cecum and colon had immunoreactivity for neuronal TRPA1, but the duodenum did not. TRPA1 immunoreactivity was also detected in inhibitory motoneurons and descending interneurons, cholinergic neurons, and intrinsic primary afferent neurons. TRPA1 activators, including cinnamaldehyde, allyl isothiocyanate (AITC), and 4-hydroxynonenal, increased [Ca(2+)](i) in myenteric neurons. These were reduced by a TRPA1 antagonist (HC-030031) or deletion of Trpa1. TRPA1 activation inhibited contractility of the segments of colon but not stomach or small intestine of Trpa1(+/+) but not Trpa1(-/-) mice; this effect was reduced by tetrodotoxin or N(G)-nitro-l-arginine methyl ester. Administration of AITC by gavage did not alter gastric emptying or small intestinal transit, but luminal AITC inhibited colonic transit via TRPA1.

CONCLUSIONS

Functional TRPA1 is expressed by enteric neurons, and activation of neuronal TRPA1 inhibits spontaneous neurogenic contractions and transit of the colon.

Effect of endurance exercise training on oxidative stress in spontaneously hypertensive rats (SHR) after emergence of hypertension

The purpose of this study is to elucidate the effect of wheel training on oxidative stress maker levels in spontaneous hypertensive rats (SHR). 4-hydroxynonenal and 3-nitrotyrosine levels in the aorta of SHRs were allowed to run for 10 weeks from the age of 15 weeks were measured and compared with those of nonexercised SHRs. The 4-hydroxynonenal and 3-nitrotyrosine levels in the exercised group were significantly lower than those in the nonexercised group. The exercised group showed a significant increase of manganese-containing superoxide dismutase. Endurance exercise showed a possible suppressing effect on the arteriosclerosis development by reducing oxidative stress, even after emergence of hypertension.

Pursuing enigmas on ischemic heart disease and sudden cardiac death

This article reviews what our colleagues have found as to how ischemic injury or cell death develop in myocardium through Ca(2+)-dependent protease calpain and how compensatory responses evolve through activation of intracellular signaling molecules including PKC isoforms, MAP kinase family enzymes and PI3 kinase. We also addressed how restraint or other psychological stress evokes hypertension and cardiovascular responses in signaling molecules or genes. Unexpectedly, carbon monoxide protects heart and cardiogenic cells against ischemia-resperfusion injury. When I think back, the unresolved cases of autopsies provided ideas for experimental study, which then taught us how the other cases died.

Molecular fingerprints of neutrophil-dependent oxidative stress in inflammatory bowel disease

Neutrophil accumulation within epithelial crypts and in the intestinal mucosa directly correlates with clinical disease activity and epithelial injury in inflammatory bowel disease (IBD). Current advances have defined the mechanisms by which neutrophils are activated or migrate across endothelial and mucosal epithelial cells. A better understanding of this process will likely provide new insights into novel treatment strategies for IBD. Especially, activated neutrophils produce reactive oxygen and nitrogen species and myeloperoxidase within intestinal mucosa, which induce oxidative stress. Posttranslational modification of proteins generated by these reactive species serves as a "molecular fingerprint" of protein modification by lipid peroxidation-, nitric oxide-, and myeloperoxidase-derived oxidants. Measurement of these modified proteins may serve both as a quantitative index of oxidative stress and an important new biological marker of clinical relevance to IBD. We have succeeded in the clinical development of a novel granulocyte adsorptive apheresis therapy for IBD. In this review, we discuss current advances in defining the role of neutrophil-dependent oxidative stress in IBD.

Expression of peroxiredoxin I in plasma cells of oral inflammatory diseases

The participation of reactive oxygen species (ROS) in the immune response, both as pathogen killers and as mediators of signaling pathways, is well established. However, little is known about the enzymes responsible for ROS elimination in immune cells. Peroxiredoxin I (PrdxI) is a multifunctional enzyme that exhibits thioredoxin-dependent peroxidase activity. It has been described as a major hydrogen peroxide (H(2)O(2))-inducible protein in mouse peritoneal macrophages. In order to characterize its participation in the antioxidant defense of inflammatory/immune cells in greater detail, we evaluated its expression at sites of the oral cavity affected by inflammatory disorders induced by different agents (infectious, chemical, mechanical or tumor). In this study we demonstrated, by immunohistochemistry, that PrdxI is expressed in plasma cells, but not in B lymphocytes, regardless of the inflammation-inducing agent. We suggest that PrdxI induction could be considered a crucial part of the cellular adaptive response to the B-cell differentiation process to cope with the additional H(2)O(2) associated with massive disulfide bond formation during immunoglobulin folding in the endoplasmic reticulum of plasma cells. PrdxI could diminish the tissue damage that accompanies inflammation.