2-butenal and Inflammation

Crotonaldehyde is a ubiquitous hazardous pollutant, present in cigarette smoke and automobile exhaust and is endogenously generated by lipid peroxidation. Most of the current studies focus on its lung toxicity. However, there have been few investigations on the cardiac and renal toxicity caused by crotonaldehyde exposure. We hypothesized that oral intake of crotonaldehyde can cause inflammatory and oxidative/nitrosative damage to the heart and kidneys. Therefore, we treated male rats with crotonaldehyde by gavage at 0, 2.5, 4.5, and 8.5 mg/kg/day for 120 d and evaluated the alterations in histological and serological parameters, oxidative state, and inflammation responses to explore the roles of crotonaldehyde-induced oxidative/nitrosative stress and inflammation in the heart and kidney dysfunction and to explore the relationship between heart and kidney dysfunction. We found that body weight increment, as well as heart and kidney coefficients decreased with an increasing crotonaldehyde dosage. Histological examinations indicated that crotonaldehyde exposure led to focal myocardial necrosis, cardiac fibrosis, renal tubular epithelial cell edema, and renal lymphocyte infiltration. We also assessed the impact of crotonaldehyde treatment on oxidative/nitrosative stress markers, antioxidant enzymes, inflammatory biomarkers, heart/kidney functional markers, and angiotensin II-aldosterone-brain natriuretic peptide (AngII-ALD-BNP) levels. Overall, we found that proinflammatory cytokine and malondialdehyde levels increased in a dose-dependent manner. Furthermore, crotonaldehyde treatment (4.5 and 8.5 mg/kg) significantly prevented the upregulation of antioxidant enzyme activity, thereby increasing oxidative/nitrosative stress (p < 0.05). Moreover, we found that the levels of AngII and ALD increased, whereas the levels of BNP decreased, consistent with heart and kidney dysfunction. Collectively, these results suggest that long-term, low-dose crotonaldehyde exposure leads to an imbalance in AngII-ALD-BNP levels, which mediates cardiac hemodynamic changes causing internal oxidative/nitrosative stress and inflammatory reactions, leading to renal and cardiac dysfunction in male rats.

Topics: Aldehydes; Animals; Antioxidants; Cytokines; Dose-Response Relationship, Drug; Environmental Pollutants; Heart; Inflammation; Kidney; Kidney Function Tests; Male; Myocardium; Oxidative Stress; Rats, Wistar; Time Factors

Amyloidogenesis is linked to neuroinflammation. The tyrosine-fructose Maillard reaction product, 2,4-bis(p-hydroxyphenyl)-2-butenal, possesses anti-inflammatory properties in cultured macrophages, and in an arthritis animal model. Because astrocytes and microglia are responsible for amyloidogenesis and inflammatory reactions in the brain, we investigated the anti-inflammatory and anti-amyloidogenic effects of 2,4-bis(p-hydroxyphenyl)-2-butenal in lipopolysaccharide (LPS)-stimulated astrocytes and microglial BV-2 cells.. Cultured astrocytes and microglial BV-2 cells were treated with LPS (1 μg/ml) for 24 h, in the presence (1, 2, 5 μM) or absence of 2,4-bis(p-hydroxyphenyl)-2-butenal, and harvested. We performed molecular biological analyses to determine the levels of inflammatory and amyloid-related proteins and molecules, cytokines, Aβ, and secretases activity. Nuclear factor-kappa B (NF-κB) DNA binding activity was determined using gel mobility shift assays.. We found that 2,4-bis(p-hydroxyphenyl)-2-butenal (1, 2, 5 μM) suppresses the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) as well as the production of nitric oxide (NO), reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in LPS (1 μg/ml)-stimulated astrocytes and microglial BV-2 cells. Further, 2,4-bis(p-hydroxyphenyl)-2-butenal inhibited the transcriptional and DNA binding activity of NF-κB--a transcription factor that regulates genes involved in neuroinflammation and amyloidogenesis via inhibition of IκB degradation as well as nuclear translocation of p50 and p65. Consistent with the inhibitory effect on inflammatory reactions, 2,4-bis(p-hydroxyphenyl)-2-butenal inhibited LPS-elevated Aβ42 levels through attenuation of β- and γ-secretase activities. Moreover, studies using signal transducer and activator of transcription 3 (STAT3) siRNA and a pharmacological inhibitor showed that 2,4-bis(p-hydroxyphenyl)-2-butenal inhibits LPS-induced activation of STAT3.. These results indicate that 2,4-bis(p-hydroxyphenyl)-2-butenal inhibits neuroinflammatory reactions and amyloidogenesis through inhibition of NF-κB and STAT3 activation, and suggest that 2,4-bis(p-hydroxyphenyl)-2-butenal may be useful for the treatment of neuroinflammatory diseases like Alzheimer's disease.

Topics: Aldehydes; Amyloid beta-Peptides; Animals; Astrocytes; Cell Line; Cyclooxygenase 2; Fructose; Humans; Inflammation; Interleukin-1beta; Lipopolysaccharides; Maillard Reaction; Mice; Microglia; NF-kappa B; Nitric Oxide; Nitric Oxide Synthase Type II; Reactive Oxygen Species; STAT3 Transcription Factor; Tumor Necrosis Factor-alpha; Tyrosine