Superoxide: The enigmatic chemical chameleon in neutrophil biology

The Role of Vitamins in Pediatric Urinary Tract Infection: Mechanisms and Integrative Strategies

Urinary tract infections (UTI) are among the most frequent bacterial infections in children, representing a significant cause of morbidity with potential long-term complications, including renal scarring and chronic kidney disease. This review explores the multifaceted roles of vitamins A, D, E, and C in the prevention and management of pediatric UTI. Vitamin A supports mucosal barrier integrity and immune modulation, reducing pathogen adhesion and colonization. Vitamin C exhibits antioxidant and antimicrobial properties, acidifying urine to inhibit bacterial growth and enhancing the efficacy of antibiotics. Vitamin D strengthens innate immunity by promoting antimicrobial peptide production, such as cathelicidins, and improves epithelial barrier function, while vitamin E mitigates oxidative stress, reducing renal inflammation and tissue damage. The interplay between oxidative stress, immune response, and nutritional factors is emphasized, highlighting the potential of these vitamins to restore antioxidant balance and prevent renal injury. Complementary strategies, including probiotics and phytotherapeutic agents, further enhance therapeutic outcomes by addressing microbiome diversity and providing additional antimicrobial effects. While these approaches show promise in mitigating UTI recurrence and reducing dependence on antibiotics, evidence gaps remain regarding optimal dosing, long-term outcomes, and their integration into pediatric care. By adopting a holistic approach incorporating vitamin supplementation and conventional therapies, clinicians can achieve improved clinical outcomes, support antibiotic stewardship, and reduce the risk of renal complications in children with UTI.

Dioxygenation of tryptophan residues by superoxide and myeloperoxidase

When neutrophils ingest pathogens into phagosomes, they generate large amounts of the superoxide radical through the reduction of molecular oxygen. Superoxide is essential for effective antimicrobial defense, but the precise role it plays in bacterial killing is unknown. Within phagosomes, superoxide reacts with the heme enzyme myeloperoxidase (MPO) and is converted to hydrogen peroxide, then subsequently to the bactericidal oxidant hypochlorous acid. But other reactions of superoxide with MPO may also contribute to host defense. Here, we demonstrate that MPO uses superoxide to dioxygenate tryptophan residues within model peptides via two hypochlorous acid-independent pathways. Using mass spectrometry, we show that formation of N-formylkynurenine is the favored reaction. This reaction is consistent with a direct transfer of dioxygen from an intermediate of MPO, where superoxide is bound to the active site heme iron (compound III). In addition, hydroperoxides are formed when superoxide adds to tryptophan radicals, which are produced during the peroxidase cycle of MPO. Proteomic analysis revealed that tryptophan dioxygenation occurs on the abundant neutrophil protein calprotectin and lactoferrin during phagocytosis of Staphylococcus aureus, indicating that this is a physiologically relevant modification. Our study enhances the understanding of superoxide chemistry in the phagosome. It also suggests that tryptophan dioxygenation by MPO and superoxide may occur during infection and inflammation.

Exploring the application of dietary antioxidant index for disease risk assessment: a comprehensive review

Oxidative stress contributes to the development of cardiometabolic diseases and cancers. Numerous studies have highlighted the adverse effects of high reactive oxygen species (ROS) levels in the progression of chronic noncommunicable diseases and also during infections. On the other hand, antioxidants play a crucial role in preventing oxidative stress or postponing cell damage via the direct scavenging of free radicals or indirectly via the Keap1/Nrf2/ARE pathway, among others. Dietary antioxidants can be obtained from various sources, mainly through a plant-based diet, including fruits and vegetables. The dietary antioxidant index (DAI) has been developed to assess total antioxidant intake from diet. This review delineated the performance of DAI in the risk assessment of different diseases. It is suggested that a high DAI score prevents obesity-related diseases, including diabetes mellitus, hyperuricemia, dyslipidemia, and metabolic (dysfunction)-associated steatotic liver disease (MASLD). Additionally, DAI is negatively associated with Helicobacter pylori and Human papillomavirus infection, thus reducing the risk of gastric and cervical cancer. Also, a high intake of antioxidants prevents the development of osteoporosis, miscarriage, infertility, and mental illnesses. However, further prospective observations and clinical trials are warranted to confirm the application of DAI in preventing diseases that have been studied.

Performance and Health Parameters of Sows and Their Litters Using a Probiotic Supplement Composed of Bacillus subtilis 541 and Bacillus amyloliquefaciens 516

This study investigated the efficacy of using probiotics on the performance and health parameters of sows and their litters. A randomized block design was used with 584 sows and 292 replications, with two dietary treatments: the control group (basal diet without probiotics) and the probiotic group (basal diet supplemented with 400 g/ton of a probiotic composed of Bacillus subtilis (B. subtilis) 541 and Bacillus amyloliquefaciens (B. amyloliquefaciens) 516). Feed intake was evaluated throughout the experimental period. Bodyweight and backfat thickness of the sows were measured at the beginning and end of each phase. Piglets were weighed individually at birth and at weaning. Performance variables and physiological parameters were analyzed. Sows that received the probiotic supplement exhibited increased milk production (p = 0.05) and bodyweight loss, along with reduced postpartum cortisol levels (p < 0.05). The piglets from the probiotic treatment group had higher (p < 0.001) weaning weight and fewer (p < 0.05) crushing deaths, received fewer (p < 0.001) medications, and had lower (p < 0.05) excretion of pathogenic bacteria and lower (p < 0.05) excretion of fecal Lactobacillus sp. They also had higher (p < 0.05) concentration of fecal myeloperoxidase (MPO) close to weaning and improved ileal histomorphometric measures. In conclusion, supplementation with the probiotic product improves performance and promotes health parameters of the sows their litters.

Estimation of reference interval for neutrophil activity evaluation systems: a interim report

Neutrophils play an important role in innate immunity and produce reactive oxygen species, but they can also cause inflammation and oxidative stress that can damage their own tissues. We have developed neutrophil activity evaluation systems that simultaneously monitors superoxide radicals and hypochlorite ions secreted by stimulated neutrophils in a few microliters of whole blood and have conducted clinical studies in humans. Here, we report normal reference intervals with our systems based on the results of 3,082 persons who underwent comprehensive cancer screening between February 2020 and March 2022. A total of 344 were extracted as reference individuals based on the results of the cancer screening and the reference intervals of the two systems were interim estimated considering gender and age. Reference intervals can be used as a marker of sub-clinical inflam-mation, which is difficult to detect with other blood markers.

Acute exposure to fungicide fluazinam induces cell death in the midgut, oxidative stress and alters behavior of the stingless bee Partamona helleri (Hymenoptera: Apidae)

Stingless bees (Hymenoptera: Meliponini) are pollinators of both cultivated and wild crop plants in the Neotropical region. However, they are susceptible to pesticide exposure during foraging activities. The fungicide fluazinam is commonly applied in bean and sunflower cultivation during the flowering period, posing a potential risk to the stingless bee Partamona helleri, which serves as a pollinator for these crops. In this study, we investigated the impact of acute oral exposure (24 h) fluazinam on the survival, morphology and cell death signaling pathways in the midgut, oxidative stress and behavior of P. helleri worker bees. Worker bees were exposed for 24 h to fluazinam (field concentrations 0.5, 1.5 and 2.5 mg a.i. mL-1), diluted in 50 % honey aqueous solution. After oral exposure, fluazinam did not harm the survival of worker bees. However, sublethal effects were revealed using the highest concentration of fluazinam (2.5 mg a.i. mL-1), particularly a reduction in food consumption, damage in the midgut epithelium, characterized by degeneration of the brush border, an increase in the number and size of cytoplasm vacuoles, condensation of nuclear chromatin, and an increase in the release of cell fragments into the gut lumen. Bees exposed to fluazinam exhibited an increase in cells undergoing autophagy and apoptosis, indicating cell death in the midgut epithelium. Furthermore, the fungicide induced oxidative stress as evidenced by an increase in total antioxidant and catalase enzyme activities, along with a decrease in glutathione S-transferase activity. And finally, fluazinam altered the walking behavior of bees, which could potentially impede their foraging activities. In conclusion, our findings indicate that fluazinam at field concentrations is not lethal for workers P. helleri. Nevertheless, it has side effects on midgut integrity, oxidative stress and worker bee behavior, pointing to potential risks for this pollinator.

Ten "Cheat Codes" for Measuring Oxidative Stress in Humans

Formidable and often seemingly insurmountable conceptual, technical, and methodological challenges hamper the measurement of oxidative stress in humans. For instance, fraught and flawed methods, such as the thiobarbituric acid reactive substances assay kits for lipid peroxidation, rate-limit progress. To advance translational redox research, we present ten comprehensive "cheat codes" for measuring oxidative stress in humans. The cheat codes include analytical approaches to assess reactive oxygen species, antioxidants, oxidative damage, and redox regulation. They provide essential conceptual, technical, and methodological information inclusive of curated "do" and "don't" guidelines. Given the biochemical complexity of oxidative stress, we present a research question-grounded decision tree guide for selecting the most appropriate cheat code(s) to implement in a prospective human experiment. Worked examples demonstrate the benefits of the decision tree-based cheat code selection tool. The ten cheat codes define an invaluable resource for measuring oxidative stress in humans.

Classical and nonclassical effects of angiotensin-converting enzyme: How increased ACE enhances myeloid immune function

As part of the classical renin-angiotensin system, the peptidase angiotensin-converting enzyme (ACE) makes angiotensin II which has myriad effects on systemic cardiovascular function, inflammation, and cellular proliferation. Less well known is that macrophages and neutrophils make ACE in response to immune activation which has marked effects on myeloid cell function independent of angiotensin II. Here, we discuss both classical (angiotensin) and nonclassical functions of ACE and highlight mice called ACE 10/10 in which genetic manipulation increases ACE expression by macrophages and makes these mice much more resistant to models of tumors, infection, atherosclerosis, and Alzheimer's disease. In another model called NeuACE mice, neutrophils make increased ACE and these mice are much more resistant to infection. In contrast, ACE inhibitors reduce neutrophil killing of bacteria in mice and humans. Increased expression of ACE induces a marked increase in macrophage oxidative metabolism, particularly mitochondrial oxidation of lipids, secondary to increased peroxisome proliferator-activated receptor α expression, and results in increased myeloid cell ATP. ACE present in sperm has a similar metabolic effect, and the lack of ACE activity in these cells reduces both sperm motility and fertilization capacity. These nonclassical effects of ACE are not due to the actions of angiotensin II but to an unknown molecule, probably a peptide, that triggers a profound change in myeloid cell metabolism and function. Purifying and characterizing this peptide could offer a new treatment for several diseases and prove potentially lucrative.

Assessment of In Vitro Antioxidant and Anti-Inflammatory Activities of Pumpkin (Cucurbita pepo) Natural Plant

Objectives

The objective of this research was to investigate the potential anti-inflammatory properties of the Cucurbita pepo fruit. Given the adverse effects associated with long-term use or excessive doses of conventional anti-inflammatory medications, exploring herbal therapies as alternatives has become increasingly important.

Methods

Various preliminary tests and antioxidant assays, both enzymatic and non-enzymatic, were conducted on the C . pepo fruit. Bioactive substances present in the fruit, including alkaloids, carbohydrates, flavonoids, tannins, amino acids, triterpenoids, and saponin glycosides, were identified through early analysis. Different extraction solvents, such as chloroform, methanol, and water, were utilized to extract samples. The methanolic extract was subjected to further testing for its in vitro anti-inflammatory characteristics. This involved evaluating their ability to stabilize RBC membranes, inhibit protein denaturation, and suppress proteinase activity using two concentrations (150 µg/ml and 300 µg/ml) of the extract.

Results

The methanolic extract of the C. pepo fruit exhibited strong free radical scavenging activity in both DPPH and H2O2 assays. Moreover, it demonstrated the dose-dependent stabilization of RBC membranes, resulting in reduced hemolysis, protein denaturation, and proteinase activity. These findings suggest potent anti-inflammatory effects of the methanolic extract.

Conclusion

This research study has found that the C. pepo fruit methanolic extract significantly reduced inflammation. This demonstrates the promise of natural chemicals as less risky substitutes for traditional anti-inflammatory medications. Potentially safe and efficient treatments for inflammatory illnesses could be found in herbal remedies such as the C. pepo fruit. Therefore, this study highlights the significance of exploring herbal remedies as a potential treatment option for inflammation-related diseases.

Effect of fat ingestion on postprandial oxidative status in healthy young women: a pilot study

Reactive oxygen species (ROS) and highly reactive oxygen species (hROS) secreted by leukocytes are crucial to innate immunity; however, they pose a risk of oxidative stress. To monitor their balance in daily health check-ups, optical technologies for the simultaneous measurement of ROS (superoxide radicals) and hROS (hypochlorite ions) that utilize only a few microliters of whole blood have been developed. The aim of this study was to clarify whether this system could assess the effects of fat ingestion on postprandial oxidative status. Eight healthy young Japanese women ingested a beverage containing oral fat tolerance test cream. Blood samples were collected before and 0.5, 1, 2, 4, and 6 h after fat ingestion. Blood ROS and hROS levels, oxidative stress markers, and biochemical markers were monitored. Consistent with previous studies, triglyceride levels significantly increased at 4 h (p<0.01) and returned to near-baseline levels 6 h after ingestion. ROS levels peaked significantly at 2 h (p<0.05), and hROS levels peaked significantly at 1 (p<0.05) and 2 h (p<0.01) after ingestion. This study offers an insight into the acute effects of fat ingestion on leukocyte activity and provides a methodology for monitoring postprandial oxidative status.

The neutrophil oxidant hypothiocyanous acid causes a thiol-specific stress response and an oxidative shift of the bacillithiol redox potential in Staphylococcus aureus

IMPORTANCE

Staphylococcus aureus colonizes the skin and the airways but can also lead to life-threatening systemic and chronic infections. During colonization and phagocytosis by immune cells, S. aureus encounters the thiol-reactive oxidant HOSCN. The understanding of the adaptation mechanisms of S. aureus toward HOSCN stress is important to identify novel drug targets to combat multi-resistant S. aureus isolates. As a defense mechanism, S. aureus uses the flavin disulfide reductase MerA, which functions as HOSCN reductase and protects against HOSCN stress. Moreover, MerA homologs have conserved functions in HOSCN detoxification in other bacteria, including intestinal and respiratory pathogens. In this work, we studied the comprehensive thiol-reactive mode of action of HOSCN and its effect on the reversible shift of the E BSH to discover new defense mechanisms against the neutrophil oxidant. These findings provide new leads for future drug design to fight the pathogen at the sites of colonization and infections.

Reactive Oxygen Species: A Crosslink between Plant and Human Eukaryotic Cell Systems

Reactive oxygen species (ROS) are important regulating factors that play a dual role in plant and human cells. As the first messenger response in organisms, ROS coordinate signals in growth, development, and metabolic activity pathways. They also can act as an alarm mechanism, triggering cellular responses to harmful stimuli. However, excess ROS cause oxidative stress-related damage and oxidize organic substances, leading to cellular malfunctions. This review summarizes the current research status and mechanisms of ROS in plant and human eukaryotic cells, highlighting the differences and similarities between the two and elucidating their interactions with other reactive substances and ROS. Based on the similar regulatory and metabolic ROS pathways in the two kingdoms, this review proposes future developments that can provide opportunities to develop novel strategies for treating human diseases or creating greater agricultural value.