Oxidative stress and DNA damage in critically ill patients with sepsis

RNA-DNA Differences: Mechanisms, Oxidative Stress, Transcriptional Fidelity, and Health Implications

RNA-DNA differences (RDDs) challenge the traditional view of RNA as a faithful copy of DNA, arising through RNA editing, transcriptional errors, and oxidative damage. Reactive oxygen species (ROS) play a central role, inducing lesions like 8-oxo-guanine that compromise transcription and translation, leading to dysfunctional proteins. This review explores the biochemical basis of RDDs, their exacerbation under oxidative stress, and their dual roles in cellular adaptation and disease. RDDs contribute to genomic instability and are implicated in cancers, neurodegenerative disorders, and autoimmune diseases, while also driving phenotypic diversity. Drawing on terrestrial and spaceflight studies, we highlight the intersection of oxidative stress, RDD formation, and cellular dysfunction, proposing innovative mitigation approaches. Advancements in RDD detection and quantification, along with ROS management therapies, offer new avenues to restore cellular homeostasis and promote resilience. By positioning RDDs as a hallmark of genomic entropy, this review underscores the limits of biological adaptation. Furthermore, the prevalence of guanine-rich codons in antioxidant genes increases their susceptibility to ROS-induced oxidative lesions, linking redox stress, genomic instability, and constrained adaptation. These insights have profound implications for understanding aging, disease progression, and adaptive mechanisms in both terrestrial and space environments.

Cytosolic nucleic acid sensing as driver of critical illness: mechanisms and advances in therapy

Nucleic acids from both self- and non-self-sources act as vital danger signals that trigger immune responses. Critical illnesses such as acute respiratory distress syndrome, sepsis, trauma and ischemia lead to the aberrant cytosolic accumulation and massive release of nucleic acids that are detected by antiviral innate immune receptors in the endosome or cytosol. Activation of receptors for deoxyribonucleic acids and ribonucleic acids triggers inflammation, a major contributor to morbidity and mortality in critically ill patients. In the past decade, there has been growing recognition of the therapeutic potential of targeting nucleic acid sensing in critical care. This review summarizes current knowledge of nucleic acid sensing in acute respiratory distress syndrome, sepsis, trauma and ischemia. Given the extensive research on nucleic acid sensing in common pathological conditions like cancer, autoimmune disorders, metabolic disorders and aging, we provide a comprehensive summary of nucleic acid sensing beyond critical illness to offer insights that may inform its role in critical conditions. Additionally, we discuss potential therapeutic strategies that specifically target nucleic acid sensing. By examining nucleic acid sources, sensor activation and function, as well as the impact of regulating these pathways across various acute diseases, we highlight the driving role of nucleic acid sensing in critical illness.

TREM2 alleviates sepsis-induced acute lung injury by attenuating ferroptosis via the SHP1/STAT3 pathway

Sepsis-induced acute lung injury (ALI) is a complex and life-threatening condition characterized by excessive inflammatory responses, ferroptosis, and oxidative stress. A comprehensive investigation and effective therapeutic strategies are crucial for managing this condition. In this study, we established in vivo sepsis models using lipopolysaccharide (LPS) in wild-type (WT) mice and triggering receptor expressed on myeloid cells 2 (TREM2) knockout (TREM2-KO) mice to assess lung morphology, oxidative stress, and ferroptosis. In vitro, RAW264.7 cells with TREM2 overexpression (TREM2-OE) or knockdown (TREM2-SiRNA) were utilized to assess oxidative stress and ferroptosis. RNA sequencing of LPS-stimulated cells transfected with either vector or TREM2-OE revealed significant differences in inflammation- and ferroptosis-related pathways. LPS-induced lung injury and ferroptosis were exacerbated in TREM2-KO mice and TREM2-SiRNA cells but alleviated by the ferroptosis inhibitor ferrostatin-1 (Fer-1). Mechanistically, TREM2-KO led to SHP1 downregulation and STAT3-P upregulation, which were reversed by the SHP1 agonist SC-43. These findings highlight the role of TREM2 in the SHP1/STAT3 signaling pathway and its regulatory effects on ferroptosis. Our study demonstrates that TREM2, via the SHP1/STAT3 pathway, suppresses oxidative stress and ferroptosis, thereby significantly mitigating sepsis-induced ALI. These results underscore the pivotal role of TREM2 in modulating inflammatory responses and immunity, providing a theoretical foundation for developing therapeutic strategies.

Molecular heterogeneity in pediatric sepsis: identification of oxidative stress-related subtypes and diagnostic biomarkers through integrated bioinformatics analysis

BACKGROUND

Pediatric sepsis is a life-threatening condition characterized by a dysregulated immune response to infection, often involving heightened oxidative stress. Understanding the molecular heterogeneity of sepsis can provide insights into potential therapeutic targets and diagnostic biomarkers.

METHODS

Machine learning approaches were employed to identify diagnostic biomarkers. Unsupervised clustering was performed to identify distinct sepsis subtypes. We conducted an integrative analysis combining Gene Set Variation Analysis (GSVA), Gene Set Enrichment Analysis (GSEA), differential gene expression, and functional enrichment to study oxidative stress-related subgroups in sepsis patients. Immune cell infiltration and immune-related pathway activities were analyzed using the ssGSEA algorithm. GSVA and GSEA indicated significant enrichment of oxidative stress-related pathways in sepsis patients compared to controls.

RESULTS

Differential expression analysis identified 371 upregulated and 304 downregulated genes in sepsis, with 34 genes linked to oxidative stress. LASSO and Random Forest analyses highlighted key diagnostic genes (GBA and MGST1), validated in independent datasets (GSE13904) with high diagnostic accuracy (AUC: GBA = 0.924, MGST1 = 0.857). Unsupervised clustering revealed two distinct sepsis subtypes with differential immune cell infiltration and pathway activities: Subtype 1 showed higher T cell and TFH infiltration, while Subtype 2 exhibited increased macrophage infiltration. Functional enrichment and GSEA identified key metabolic, oxidative stress, and immune pathways that were enriched in Subtype 2.

CONCLUSION

Our comprehensive bioinformatics analysis unveils significant oxidative stress-related molecular heterogeneity in sepsis, identifying potential diagnostic biomarkers and therapeutic targets. Personalized medicine approaches targeting specific oxidative stress pathways and immune responses could enhance sepsis management and patient outcomes.

Total Antioxidant Status in Critically Ill Patients with Traumatic Brain Injury and Secondary Organ Failure-A Systematic Review

Introduction: The available literature indicates that oxidant-antioxidant imbalance plays a significant role in the pathophysiology of traumatic brain injury and the subsequent secondary organ dysfunctions. However, there is a lack of studies summarizing the knowledge in this area, and no clear guidelines exist regarding the use of biomarkers of oxidative stress as diagnostics tools. Methods: The present work aims to provide a systematic review of the literature on the use of total antioxidant capacity (TAC) assays in predicting the outcomes of traumatic brain injury (TBI). A literature search was conducted up to 1 September 2024, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines, using the PubMed and Scopus databases. Based on the inclusion criteria, 24 studies were used for the final review. Results: Promising data indicate that TAC assays are useful in predicting 30-day mortality and neurological outcomes. Moreover, they correlate with radiological findings on CT scans in brain injury and the clinical classifications of injuries, as well as the parameters of organ failure. Conclusions: Total antioxidant capacity assays can be used to assess the extent of brain damage and prognosticate general vital functions. Future experiments should include long-term randomized clinical trials on larger populations of TBI patients.

The emerging role of mtDNA release in sepsis: Current evidence and potential therapeutic targets

Sepsis is a systemic inflammatory reaction caused by infection, and severe sepsis can develop into septic shock, eventually leading to multiorgan dysfunction and even death. In recent years, studies have shown that mitochondrial damage is closely related to the occurrence and development of sepsis. Recent years have seen a surge in concern over mitochondrial DNA (mtDNA), as anomalies in this material can lead to cellular dysfunction, disruption of aerobic respiration, and even death of the cell. In this review, we discuss the latest findings on the mechanisms of mitochondrial damage and the molecular mechanisms controlling mitochondrial mtDNA release. We also explored the connection between mtDNA misplacement and inflammatory activation. Additionally, we propose potential therapeutic targets of mtDNA for sepsis treatment.

The Potential Predictive Role of Oxidative Stress and Antioxidant Parameters Regarding Mortality and the Type of Causative Agent in Sepsis

Oxidative stress represents an imbalance between oxidants and antioxidants, with a predominance of oxidants leading to cellular and tissue damage. Given the limited number of studies showing the predictive value of oxidative stress factors regarding sepsis type, the objectives of this study emerged as follows: to determine whether pro-oxidant and antioxidant values could predictively differentiate between Gram-positive (GP) and Gram-negative (GN) sepsis. Additionally, the study sought to assess whether bacterial type impacts treatment outcomes in sepsis patients. This prospective, observational cohort longitudinal study included 87 patients diagnosed with sepsis according to the Third International Consensus on Sepsis and Septic Shock (Sepsis-3) criteria. Following the sepsis diagnosis, blood, urine, bronchoalveolar lavage (BAL), and swabs/punctures were sampled and microbiologically analyzed. Sampling was repeated 24 hours after the first collection. Based on the microbiological results, four groups of subjects were formed: the GP group included septic patients in whom one or more GP bacteria were isolated by microbiological analysis; the GN group included septic patients in whom one or more GN bacteria were isolated; the GP/GN group included septic patients with both GP and GN bacteria isolated; and the negative culture (NC) group included septic patients in whom no pathogenic microorganisms were detected by microbiological analysis. Additionally, after sepsis diagnosis, oxidative stress markers, i.e., thiobarbituric acid reactive substances (TBARS), nitrite ion radical (NO₂⁻), hydrogen peroxide (H₂O₂), superoxide ion radical (O₂⁻), and antioxidants: superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) were determined from blood samples. Blood sampling was repeated 24 hours after the first collection. On comparing pro-oxidant values relative to the type of infection in septic patients, measured on the first and second days, no statistically significant differences were observed for the analyzed parameters, except for delta (Δ) O₂⁻. A statistically significant increase was noted in the GN group of septic patients (p = 0.02). On comparing antioxidant values relative to infection type in septic patients, measured on the first and second days, no statistically significant differences were found for the analyzed parameters. Based on the measured values of pro-oxidants and antioxidants in this study, it is evident that they do not have predictive significance for the final treatment outcome and the type of sepsis-causing pathogen. These results underscore the need for further research on the predictive role of oxidative stress in sepsis.