4-Hydroxynonenal in Redox Homeostasis of Gastrointestinal Mucosa: Implications for the Stomach in Health and Diseases

Machine Learning Identify Ferroptosis-Related Genes as Potential Diagnostic Biomarkers for Gastric Intestinal Metaplasia

BACKGROUND

Gastric intestinal metaplasia(GIM) is an independent risk factor for GC, however, its pathogenesis is still unclear. Ferroptosis is a new type of programmed cell death, which may be involved in the process of GIM. The purpose of this study was to analyze the expression of ferroptosis-related genes (FRGs) in GIM tissues and to explore the relationship between ferroptosis and GIM.

METHOD

The results of GIM tissue full transcriptome sequencing were downloaded from Gene Expression Omnibus(GEO) database. R software (V4.2.0) and R packages were used for screening and enrichment analysis of differentially expressed genes(DEGs). The key genes were screened by least absolute shrinkage and selection operator(LASSO) and support vector machine-recursive feature elimination(SVM-RFE) algorithm. Receiver operating characteristic(ROC) curve was used to evaluate the diagnostic efficacy of key genes in GIM. Clinical samples were used to further validate hub genes.

RESULTS

A total of 12 differentially expressed ferroptosis-related genes (DEFRGs) were identified. Using two machine learning algorithms, GOT1, ALDH3A2, ACSF2 and SESN2 were identified as key genes. The area under ROC curve (AUC) of GOT1, ALDH3A2, ACSF2 and SESN2 in the training set were 0.906, 0.955, 0.899 and 0.962 respectively, and the AUC in the verification set were 0.776, 0.676, 0.773 and 0.880, respectively. Clinical samples verified the differential expression of GOT1, ACSF2, and SESN2 in GIM.

CONCLUSION

We found that there was a significant correlation between ferroptosis and GIM. GOT1, ACSF2 and SESN2 can be used as diagnostic markers to effectively identify GIM.

Colonic expression of glutathione S-transferase alpha 4 and 4-hydroxynonenal adducts is correlated with the pathology of murine colitis-associated cancer

Chronic inflammation-induced oxidative stress is an important driving force for developing colitis-associated cancer (CAC). 4-hydroxynonenal (4-HNE) is a highly reactive aldehyde derived from lipid peroxidation of ω-6 polyunsaturated fatty acids that contributes to colorectal carcinogenesis. Glutathione S-transferase alpha 4 (Gsta4) specifically conjugates glutathione to 4-HNE and thereby detoxifies 4-HNE. The correlation of these oxidative biomarkers with the pathological changes in CAC is, however, unclear. In this study, we investigated the expression of Gsta4 and 4-HNE adducts in azoxymethane/dextran sulfate sodium (AOM/DSS)-induced murine CAC, and analyzed the correlations of 4-HNE and Gsta4 with inflammatory cytokines and the pathological scores in the colon biopsies. Real-time quantitative PCR showed that expression of IL6, TNFα, and Gsta4 sequentially increased in colon tissues for mice treated with DSS for 1, 2, and 3 cycles, respectively. Moreover, immunohistochemical staining showed remarkably increased expression of 4-HNE adducts, Gsta4, TNFα, and IL6 in the colon biopsies after 3 cycles of DSS treatment. Correlation analysis demonstrated that 4-HNE adducts in the colon biopsies were positively correlated with Gsta4 expression. Additionally, the expression of Gsta4 and 4-HNE adducts were strongly correlated with the pathological changes of colon, as well as the expression of TNFα and IL6 in colon tissues. These results provide evidence for the association of oxidative biomarkers Gsta4 and 4-HNE with the pathological changes of CAC and may help developing novel histopathological biomarkers and prevention targets for CAC.

Xiangshao Decoction alleviates gastric mucosal injury through NRF2 signaling pathway and reduces neuroinflammation in gastric ulcer rats

BACKGROUND

A type of gastric mucosal injury disease known as gastric ulcer (GU) is clearly connected to the aberrant release of gastric acid. Traditional botanicals have the potential for anti-inflammation, anti-oxidation, and other multitarget therapies, as well as being safe.

PURPOSE

The purpose of this study was to investigate the potential effects of Xiangshao Decoction (XST) on gastric mucosal injury in GU rats and to explore the possible molecular mechanisms.

METHODS

After identifying XST and its components, we established GU rats and cell models by acetic acid and H₂O₂ induction, respectively. SOD and MDA indexes in gastric tissues and GES-1 cells, and the serum levels of BDNF, ALT, and AST were detected with relevant kits, changes of the gastric mucosa were observed and recorded, and gastric tissue pathology was observed by H&E staining. The production of ROS in GES-1 cells was detected by fluorescent probes. Cell transfection techniques were used to silence or overexpress NRF2. The mRNA or protein expressions of NRF2, KEAP1, NQO1, HO-1, SOD2, IL-1β, IL-6, TNF-α, IBA1, GFAP, or γ-H2AX in the gastric tissue, hippocampus, or GES-1 cells were measured via qPCR, Western blot, immunofluorescence staining, or immunohistochemical staining.

RESULTS

The pH of gastric acid, ulcer score, and pathological damage score in GU rats could be reversed by XST administration. Expressions of IL-1β, IL-6, and TNF-α in the gastric mucosal tissues and the hippocampus of GU rats after administration of XST were down. Expressions of NRF2, NQO1, HO-1, SOD2, etc. in the gastric mucosal tissues and BDNF in the hippocampus were up-regulated. The production of ROS and MDA and the expressions of IL-1β, IL-6, TNF-α, and KEAP1 in H₂O₂-induced GES-1 cells were significantly reduced after XST intervention, while the activities of SOD and the expression of NRF2, NQO1, HO-1, and SOD2 were significantly increased, and these could be blocked by silencing NRF2 expression.

CONCLUSIONS

XST can improve oxidative stress injury and inflammatory response in GU rats and cell models, and its mechanism is mediated by the NRF2 signaling pathway.

Extra virgin olive oil inhibits Helicobacter pylori growth in vitro and the development of mice gastric mucosa lesions in vivo

Helicobacter pylori infection is widespread worldwide, with more than a half of the world population infected. H. pylori antibiotic-resistant strains and non-compliance to therapy are the major causes of H. pylori eradication failure. The search for new therapies based on plant extracts is a scientific interest field. The present study was conducted to evaluate the effect in vitro of extra virgin olive oil (EVOO), hydroxytyrosol (HT), and oleuropein (Olp) against two H. pylori strains and the effect in vivo of the oral administration of EVOO on the gastric mucosa of BALB/c mice infected with this microorganism. The broth microdilution method assayed the antibacterial in vitro activity of EVOO, HT, and Olp against H. pylori strains. For in vivo studies, male BALB/c mice were infected orally with an H. pylori suspension every 72 h. Four groups were used: (1) Control, (2) H. pylori-infected (HP), (3) EVOO, and (4) HP + EVOO. Mice were sacrificed at 7, 15, and 30 days. The stomachs were removed and observed under a microscope. Scoring of the degree of erosion was determined. Samples were processed by histological techniques for light microscopy. Macroscopic analysis showed that the presence of small erosions increased, both in number and size, in the infected group. Animals infected and treated with EVOO exhibited the presence of fewer erosions, which decreased in number as the treatment progressed. The mucosa of the control and EVOO groups showed normal histological characteristics at the three times studied. The mucosa of animals infected with H. pylori showed disruptions of the lining epithelium, damage to gastric glands, and vasodilation. The mucosa of animals infected with H. pylori and treated with EVOO showed morphological characteristics similar to those of normal and EVOO mucosa. For the first time, the current study showed the effect in vitro and in vivo of EVOO and combined administration of HT and Olp against H. pylori using an animal model. Future studies are needed to establish the mechanism of EVOO’s action at the gastric mucosa level to propose this product as a natural antimicrobial agent for the treatment of gastric H. pylori infections.

Efficacy and Safety of Zuojin Pill for the Treatment of Chronic Nonatrophic Gastritis: A Randomized Active-Controlled Clinical Trial

Objective

Zuojin pill (ZJP) is used as the classical prescription for a wide variety of digestive diseases. However, there is a lack of direct evidence for its use in the treatment of chronic nonatrophic gastritis (CNG). In particular, there is a lack of rigorous trials of randomized controlled designs. In this study, a randomized active-controlled clinical trial was performed to verify the efficacy and safety of ZJP in detail.

Methods

Patients with CNG were divided into the ZJP group and the Marzulene-S granule group. Patients were enrolled from September 2019 to February 2021 (ChiCTR2000040549). Endoscopy and histology scores were evaluated as the primary outcome measure. The Helicobacter pylori positive rate and the disappearance rate of symptoms were also measured to reflect the outcomes. Finally, adverse events were also calculated as the index of safety.

Results

A total of 68 eligible patients were enrolled in this trial and randomly divided into two groups with baseline comparability. ZJP was able to improve the red plaques as well as bile reflux scores compared with Marzulene-S granule (P=0.043 and P=0.019, respectively). Moreover, it also remarkably alleviated the active chronic inflammation score (P=0.043). However, there was no difference between the Helicobacter pylori positivity rate (P=0.752). The symptom scores of abdominal distension (P=0.004), belching (P=0.010), and loss of appetite (P=0.019) were alleviated by ZJP, but nausea and vomiting were not (P=0.616). ZJP can also be considered safe with no obvious adverse effects.

Conclusion

ZJP might decrease mucosal injury and alleviate symptoms in CNG. In addition, more large-scale clinical trials should be carried out to further confirm its clinical efficacy and safety.

Statins' Regulation of the Virulence Factors of Helicobacter pylori and the Production of ROS May Inhibit the Development of Gastric Cancer

Conventionally, statins are used to treat high cholesterol levels. They exhibit pleiotropic effects, such as the prevention of cardiovascular disease and decreased cancer mortality. Gastric cancer (GC) is one of the most common cancers, ranking as the third leading global cause of cancer-related deaths, and is mainly attributed to chronic Helicobacter pylori infection. During their co-evolution with hosts, H. pylori has developed the ability to use the cellular components of the host to evade the immune system and multiply in intracellular niches. Certain H. pylori virulence factors, including cytotoxin-associated gene A (CagA), vacuolating cytotoxin A (VacA), and cholesterol-α-glucosyltransferase (CGT), have been shown to exploit host cholesterol during pathogenesis. Therefore, using statins to antagonize cholesterol synthesis might prove to be an ideal strategy for reducing the occurrence of H. pylori-related GC. This review discusses the current understanding of the interplay of H. pylori virulence factors with cholesterol and reactive oxygen species (ROS) production, which may prove to be novel therapeutic targets for the development of effective treatment strategies against H. pylori-associated GC. We also summarize the findings of several clinical studies on the association between statin therapy and the development of GC, especially in terms of cancer risk and mortality.

Associations of Human Colorectal Adenoma with Serum Biomarkers of Body Iron Stores, Inflammation and Antioxidant Protein Thiols

Red and processed meat consumption and obesity are established risk factors for colorectal adenoma (CRA). Adverse changes in biomarkers of body iron stores (total serum iron, ferritin, transferrin and transferrin saturation), inflammation (high-sensitivity C-reactive protein [hs-CRP]) and anti-oxidative capacity (total of thiol groups (-S-H) of proteins [SHP]) might reflect underlying mechanisms that could explain the association of red/processed meat consumption and obesity with CRA. Overall, 100 CRA cases (including 71 advanced cases) and 100 CRA-free controls were frequency-matched on age and sex and were selected from a colonoscopy screening cohort. Odds ratios (OR) and 95% confidence intervals (95%CI) for comparisons of top and bottom biomarker tertiles were derived from multivariable logistic regression models. Ferritin levels were significantly positively associated with red/processed meat consumption and hs-CRP levels with obesity. SHP levels were significantly inversely associated with obesity. Transferrin saturation was strongly positively associated with overall and advanced CRA (ORs [95%CIs]: 3.05 [1.30-7.19] and 2.71 [1.03-7.13], respectively). Due to the high correlation with transferrin saturation, results for total serum iron concentration were similar (but not statistically significant). Furthermore, SHP concentration was significantly inversely associated with advanced CRA (OR [95%CI]: 0.29 [0.10-0.84]) but not with overall CRA (OR [95%CI]: 0.65 [0.27-1.56]). Ferritin, transferrin, and hs-CRP levels were not associated with CRA. High transferrin saturation as a sign of iron overload and a low SHP concentration as a sign of redox imbalance in obese patients might reflect underlying mechanisms that could in part explain the associations of iron overload and obesity with CRA.

Synthesis, Characterization and In Vitro Evaluation of Novel 5-Ene-thiazolo[3,2-b][1,2,4]triazole-6(5H)-ones as Possible Anticancer Agents

The present paper is devoted to the search for drug-like molecules with anticancer properties using the thiazolo[3,2-b][1,2,4]triazole-6-one scaffold. A series of 24 novel thiazolo-[3,2-b][1,2,4]triazole-6-ones with 5-aryl(heteryl)idene- and 5-aminomethylidene-moieties has been synthesized employing three-component and three-stage synthetic protocols. A mixture of Z/E-isomers was obtained in solution for the synthesized 5-aminomethylidene-thiazolo[3,2-b]-[1,2,4]triazole-6-ones. The compounds have been studied for their antitumor activity in the NCI 60 lines screen. Some compounds present excellent anticancer properties at 10 μM. Derivatives 2h and 2i were the most active against cancer cell lines without causing toxicity to normal somatic (HEK293) cells. A preliminary SAR study had been performed for the synthesized compounds.

Glucose as a Major Antioxidant: When, What for and Why It Fails?

A human organism depends on stable glucose blood levels in order to maintain its metabolic needs. Glucose is considered to be the most important energy source, and glycolysis is postulated as a backbone pathway. However, when the glucose supply is limited, ketone bodies and amino acids can be used to produce enough ATP. In contrast, for the functioning of the pentose phosphate pathway (PPP) glucose is essential and cannot be substituted by other metabolites. The PPP generates and maintains the levels of nicotinamide adenine dinucleotide phosphate (NADPH) needed for the reduction in oxidized glutathione and protein thiols, the synthesis of lipids and DNA as well as for xenobiotic detoxification, regulatory redox signaling and counteracting infections. The flux of glucose into a PPP—particularly under extreme oxidative and toxic challenges—is critical for survival, whereas the glycolytic pathway is primarily activated when glucose is abundant, and there is lack of NADP⁺ that is required for the activation of glucose-6 phosphate dehydrogenase. An important role of glycogen stores in resistance to oxidative challenges is discussed. Current evidences explain the disruptive metabolic effects and detrimental health consequences of chronic nutritional carbohydrate overload, and provide new insights into the positive metabolic effects of intermittent fasting, caloric restriction, exercise, and ketogenic diet through modulation of redox homeostasis.

Recent development on liquid chromatography-mass spectrometry analysis of oxidized lipids

Polyunsaturated fatty acids (PUFAs) in the cellular membrane can be oxidized by various enzymes or reactive oxygen species (ROS) to form many oxidized lipids. These metabolites are highly bioactive, participating in a variety of physiological and pathophysiological processes. Mass spectrometry (MS), coupled with Liquid Chromatography, has been increasingly recognized as an indispensable tool for the analysis of oxidized lipids due to its excellent sensitivity and selectivity. We will give an update on the understanding of the molecular mechanisms related to generation of various oxidized lipids and recent progress on the development of LC-MS in the detection of these bioactive lipids derived from fatty acids, cholesterol esters, and phospholipids. The purpose of this review is to provide an overview of the formation mechanisms and technological advances in LC-MS for the study of oxidized lipids in human diseases, and to shed new light on the potential of using oxidized lipids as biomarkers and mechanistic clues of pathogenesis related to lipid metabolism. The key technical problems associated with analysis of oxidized lipids and challenges in the field will also discussed.

An update on lipid oxidation and inflammation in cardiovascular diseases

Cardiovascular diseases (CVD), including ischemic heart diseases and cerebrovascular diseases, are the leading causes of morbidity and mortality worldwide. Atherosclerosis is the major underlying factor for most CVD. It is well-established that oxidative stress and inflammation are two major mechanisms leading to atherosclerosis. Under oxidative stress, polyunsaturated fatty acids (PUFA)-containing phospholipids and cholesterol esters in cellular membrane and lipoproteins can be readily oxidized through a free radical-induced lipid peroxidation (LPO) process to form a complex mixture of oxidation products. Overwhelming evidence demonstrates that these oxidized lipids are actively involved in the inflammatory responses in atherosclerosis by interacting with immune cells (such as macrophages) and endothelial cells. In addition to lipid lowering in the prevention and treatment of atherosclerotic CVD, targeting chronic inflammation has been entering the medical realm. Clinical trials are under way to lower the lipoprotein (a) (Lp(a)) and its associated oxidized phospholipids, which will provide clinical evidence that targeting inflammation caused by oxidized lipids is a viable approach for CVD. In this review, we aim to give an update on our understanding of the free radical oxidation of LPO, analytical technique to analyze the oxidation products, especially the oxidized phospholipids and cholesterol esters in low density lipoproteins (LDL), and focusing on the experimental and clinical evidence on the role of lipid oxidation in the inflammatory responses associated with CVD, including myocardial infarction and calcific aortic valve stenosis. The challenges and future directions in understanding the role of LPO in CVD will also be discussed.

Effects of Docosahexaenoic Acid and Its Peroxidation Product on Amyloid-β Peptide-Stimulated Microglia

Growing evidence suggests that docosahexaenoic acid (DHA) exerts neuroprotective effects, although the mechanism(s) underlying these beneficial effects are not fully understood. Here we demonstrate that DHA, but not arachidonic acid (ARA), suppressed oligomeric amyloid-β peptide (oAβ)-induced reactive oxygen species (ROS) production in primary mouse microglia and immortalized mouse microglia (BV2). Similarly, DHA but not ARA suppressed oAβ-induced increases in phosphorylated cytosolic phospholipase A₂ (p-cPLA₂), inducible nitric oxide synthase (iNOS), and tumor necrosis factor-α (TNF-α) in BV2 cells. LC-MS/MS assay indicated the ability for DHA to cause an increase in 4-hydroxyhexenal (4-HHE) and suppress oAβ-induced increase in 4-hydroxynonenal (4-HNE). Although oAβ did not alter the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, exogenous DHA, ARA as well as low concentrations of 4-HHE and 4-HNE upregulated this pathway and increased production of heme oxygenase-1 (HO-1) in microglial cells. These results suggest that DHA modulates ARA metabolism in oAβ-stimulated microglia through suppressing oxidative and inflammatory pathways and upregulating the antioxidative stress pathway involving Nrf2/HO-1. Understanding the mechanism(s) underlying the beneficial effects of DHA on microglia should shed light into nutraceutical therapy for the prevention and treatment of Alzheimer's disease (AD).