1. Introduction
Oxidative stress, characterized by the imbalance between pro-oxidants and anti-oxidant capacity, significantly influences the progression of inflammatory, metabolic, and other chronic liver disease (CLD). Chronic liver injury may present as fibrosis, cholestasis, necrosis, and cirrhosis [
1]. Liver cirrhosis represents the terminal phase of multiple forms of chronic liver disease, with fibrosis serving as its precursor. The global burden of liver disease is often underestimated, yet it continues to increase [
2]. Alcohol consumption and chronic infections from the hepatitis B virus (HBV) and/or the hepatitis C virus (HCV) are primary causes of liver cirrhosis. In 2018, liver cirrhosis was identified as the 11th leading cause of mortality globally [
3], with first-year mortality rates varying from 1% to 57% based on disease stage [
1,
4].
Pathological features universally observed in liver cirrhosis include hepatocyte degeneration and necrosis, the substitution of liver parenchyma with fibrotic tissue and regenerative nodules, and a decline in liver function. High exposure to alcohol induces structural and functional changes in the liver due to two interconnected processes: oxidative stress and inflammation [
5]. Alcohol has the potential to elevate the production of reactive oxygen and nitrogen species (ROS, RNS), which can subsequently induce profibrogenic cytokines, trigger the release of various inflammatory markers, and promote collagen synthesis in the context of liver fibrosis progression [
1,
6]. Reactive oxygen species are molecules containing oxygen that are generated during standard metabolic processes. The organism possesses two systems for neutralizing the detrimental effects of endogenous reactive oxygen species: enzymatic and non-enzymatic antioxidants [
7]. The liver typically maintains the equilibrium between internal antioxidants and ROS to effectively neutralize free radicals produced by viruses and various endogenous and exogenous substances processed by the organ. The oxidative to antioxidative balance can shift towards oxidative status under specific conditions, due to an increase in ROS production or a depletion of antioxidants. When the liver is subjected to persistent oxidative stress, the resultant free radical damage escalates, leading to inflammation and fibrosis [
8].
Oxidative stress induces liver injury by altering key biological molecules, including deoxyribonucleic acid (DNA), proteins, and lipids [
9]. Previous studies indicate that DNA and protein oxidation, along with lipid peroxidation products, modulate signaling pathways related to gene transcription, protein expression, apoptosis, and hepatic stellate cell activation, thereby contributing to the onset and progression of liver fibrosis [
10,
11]. Inflammation is a critical component of the immune response, characterized by the recruitment of inflammatory cells to combat diverse harmful stimuli.
The relationship between oxidative stress and inflammation in the development of liver disease has long captured researchers’ interest. Excessive inflammatory cells can generate increased levels of ROS and RNS, which in turn may enhance the expression of genes encoding proinflammatory cytokines. Oxidative stress and inflammation are closely linked, forming a vicious cycle that contributes to the progression of cirrhosis and ultimately hepatocellular carcinoma in liver diseases [
12,
13].
The present study aimed to evaluate the markers of oxidative stress, with the goal of developing new predictive tools for non-invasive paraclinical investigations of disease outcomes in patients with liver cirrhosis.
Among the most widely studied biomarkers of oxidative stress in chronic liver disease are malondialdehyde (MDA) and 8-epi-prostaglandin F2α (8-iso-PGF2α; F2-isoprostanes). MDA is a reactive end-product of lipid peroxidation that readily forms adducts with DNA and proteins, thereby modulating transcriptional regulation, apoptosis, and hepatic stellate cell activation. In patients with cirrhosis, serum MDA levels are consistently reported to be significantly elevated compared with healthy controls, and these elevations have been correlated with clinical severity indices such as Child–Pugh score, presence of ascites, and esophageal varices [
14,
15]. Furthermore, MDA has been associated with extrahepatic complications.
Nevertheless, the clinical interpretation of MDA is hampered by methodological limitations. The classical spectrophotometric TBARS assay often lacks specificity, as it can detect other aldehydes and reactive substances, thus overestimating true MDA concentrations. More advanced methods, such as high-performance liquid chromatography (HPLC) or gas chromatography–mass spectrometry (GC-MS), offer superior accuracy and reproducibility [
16,
17]. When measured by these robust approaches, MDA has shown strong associations with portal hypertension and liver decompensation, reinforcing its potential as a prognostic biomarker in cirrhosis.
In contrast, 8-iso-PGF2α is considered the gold standard marker of lipid peroxidation in vivo, due to its chemical stability, specificity for free-radical-mediated oxidation of arachidonic acid, and reliable quantification in both plasma and urine [
18,
19,
20]. Elevated concentrations of 8-iso-PGF2α have been documented in alcoholic-related liver disease (ARDL), metabolic dysfunction-associated steatotic liver disease (MASLD), and cirrhosis. Importantly, urinary excretion of 8-iso-PGF2α decreases following alcohol abstinence, indicating its responsiveness to dynamic changes in oxidative stress [
19,
20]. Additionally, 8-iso-PGF2α is mechanistically linked to the activation of NADPH oxidase (particularly NOX2), a major enzymatic source of reactive oxygen species in immune and vascular cells [
21]. Experimental studies have demonstrated that isoprostanes can stimulate collagen synthesis in activated hepatic stellate cells, directly contributing to fibrogenesis [
22].
Analytically, GC-MS or LC-MS/MS are regarded as reference techniques for accurate measurement of 8-iso-PGF2α, while immunoassays may be used in clinical or epidemiological settings but require careful validation. Notably, urinary measurements are preferable, as they are less prone to artifactual generation ex vivo and provide a more reliable index of systemic oxidative stress [
18,
20,
23].
Taken together, the combined assessment of MDA and 8-iso-PGF2α offers complementary insights: MDA reflects the systemic oxidative burden and correlates with disease severity, while 8-iso-PGF2α provides a dynamic and mechanistically relevant index of lipid peroxidation. Integrating both biomarkers may improve non-invasive risk stratification and monitoring of patients with liver cirrhosis.
Despite the widespread use of clinical scores such as Child–Pugh and MELD, there remains a clinical need for simple serum biomarkers that can support risk stratification and prediction of complications in cirrhotic patients. Oxidative stress markers, including malondialdehyde (MDA) and 8-epi-prostaglandin F2α (8-iso-PGF2α), have been proposed as potential tools, yet their clinical applicability is still uncertain due to heterogeneous results. The present study aimed to evaluate the clinical value of these biomarkers in a cohort of patients with decompensated cirrhosis, by analysing their associations with Child–Pugh class, ascites, and hepatic encephalopathy. We further explored whether integrating age with MDA levels could provide an additional tool for identifying patients at higher risk of severe disease.
Clinical relevance. Beyond their pathobiological interest, serum oxidative stress biomarkers may inform risk stratification and monitoring in cirrhosis. For example, 8-iso-PGF2α reflects ongoing lipid peroxidation and has shown dynamic responsiveness to changes such as alcohol abstinence, while MDA captures the systemic oxidative burden that plausibly contributes to complications like hepatic encephalopathy. Although these markers do not replace established scores (Child–Pugh, MELD-Na), integrating them with clinical and biochemical parameters could help flag patients at risk of worsening neurocognitive status or renal–vascular instability, thereby supporting individualized follow-up and adjunctive therapy evaluation. Accordingly, our primary objective was exploratory: to assess whether serum MDA and 8-iso-PGF2α differ across clinically defined severity strata (Child–Pugh class, West Haven HE grade, and International Ascites Club ascites grade) and to examine their simple associations with routine laboratory measures. A secondary, hypothesis-generating analysis evaluated a minimal composite (Age + MDA, median-based) purely as a signal-finding step; no clinical prediction model was proposed or validated.
2. Materials and Methods
2.1. Study Design and Analyzed Population
Between October 2024 and March 2025, we screened all consecutive admissions for decompensated liver cirrhosis at the 2nd Medical Clinic of the Craiova County Emergency Hospital. This was a retrospective cohort: patients were identified from medical records, and serum aliquots collected during routine hospitalization had been stored at −80 °C in the institutional biobank, enabling retrospective ELISA measurement of oxidative stress biomarkers. After applying the prespecified exclusion criteria (see below), the final analysis set comprised n = 90 patients. Wording such as “we measured” refers to retrospective assays on pre-existing biobank aliquots; no study-specific phlebotomy or prospective follow-up was undertaken.
Decompensated liver cirrhosis was defined by the presence of ascites, esophageal varices, or hepatic encephalopathy according to institutional protocols.
Exclusion criteria and rationale: We prespecified exclusions to reduce major sources of systemic oxidative stress confounding and HE misclassification: pregnancy; type 2 diabetes and/or metabolic syndrome; active autoimmune/inflammatory disease or ongoing systemic infection/sepsis; recent systemic corticosteroids or NSAIDs; and documented substance abuse. In addition, and specific to the biobank workflow, we excluded records with missing/invalid biobank consent or absence of a stored serum aliquot suitable for assays.
Screening log: Because this was a retrospective biobank study, a prospective screening log with per-criterion counts was not maintained. After internal audit, exact counts by exclusion category could not be reconstructed with sufficient fidelity. To avoid inaccurate reporting, we list all exclusion domains and report the final analyzed cohort (n = 90); table denominators (n/N) are provided where applicable.
Etiology and medication exposures: Cirrhosis etiology was abstracted from the discharge diagnosis and chart review and categorized as alcoholic, viral (HBV/HCV), MASLD, mixed, or other; when multiple etiologies were recorded, the primary category followed the attending physician’s attribution in the discharge summary. Medication exposures at admission were abstracted from medication orders/administration records and coded as present/absent within the first 48 h for: lactulose, rifaximin, spironolactone/other diuretics, albumin infusions, statins, and antioxidant supplements. Outpatient statin use was captured if documented as active on admission. Because documentation was partially missing in some charts, these covariates were analyzed descriptively.
2.2. Data Collection
2.2.1. Sample Collection
Venous blood was drawn under routine clinical care at admission (no study-specific phlebotomy), then processed and stored at −80 °C in the institutional biobank; oxidative stress biomarkers were measured retrospectively from single-thaw aliquots. A standard procedure was followed to separate the clot by centrifugation (Hermle AG, Gosheim, Ba-den-Württemberg, Germany) at 3000× g for 10 min, no later than 4 h after collection.
Each patient’s serum sample cryotubes were labeled, sealed to prevent contamination, and kept at a temperature below −80 °C to allow for extended sample processing. Prior to assay, frozen samples were slowly thawed and centrifuged to remove precipitates. Also, a frozen sample was used for each ELISA kit from Elabscience (Houston, TX, USA).
2.2.2. Clinical Chemistry and Hematology Platforms
Routine serum chemistry (AST/ALT, ALP, GGT, bilirubin, albumin, urea, creatinine, glucose, electrolytes, proteins, LDH, lipase, amylase, CRP) was performed on an automated clinical chemistry analyzer (e.g., Cobas c-series, Roche, Basel, Switzerland). Immunoassays, when applicable, were run on Cobas e411. Complete blood count was obtained on Abbott Alinity (5-part differential). Admission ammonia (NH3) levels were not systematically measured in routine practice and were therefore unavailable for robust analysis. A complete blood count (CBC) was performed using peripheral venous blood collected in vacutainer tubes containing ethylene-diamine-tetra-acetic acid (EDTA) as an anticoagulant. Utilizing flow cytometry and Coulter’s principle, we obtained an extended leukocyte formula of 5 diff (Alinity Abbott, Abbott Park, IL, USA) and determined the hemoleucogram markers: hemoglobin (Hb), Ht, white blood cells/leukocytes (WBCs), neutrophils (NEUs), lymphocytes (LYMs), monocytes (MONs), platelets (PLTs), the erythrocyte distribution width (RDW), and the mean corpuscular volume (MCV).
ESR was conducted by the Westergren method (ESR tubes, Becton Dickinson, Franklin Lakes, NJ, USA).
2.2.3. Immunological Assessment
We used the Enzyme-Linked Immunosorbent Assay (ELISA) method at the University of Medicine and Pharmacy of Craiova’s Immunology Laboratory to measure serum oxidative stress mediator levels.
Commercial tests for each mediator were provided by the manufacturer, Elabscience (Houston, TX, USA): 8-epi-PGF2α (Cat.: E-EL-0041; sensitivity: 9.38 pg/mL; detection range: 15.63–1000 pg/mL), MDA (Cat.: E-EL-0060; sensitivity: 18.75 ng/mL; detection range: 31.25–2000 ng/mL).
The manufacturer’s instructions and recommended procedures were followed during the dilutions and processing steps. The procedures utilized a standard optical analyzer (Asys Expert Plus UV G020 150 Microplate Reader, ASYS Hitech GmbH, Eugendorf, Austria) with a wavelength of 450 nm.
2.2.4. Pre-Analytical Handling
Venous blood was drawn under routine clinical conditions in the morning. Serum was separated within ≤4 h of collection, visually inspected, aliquoted (0.5–1.0 mL), and stored at −80 °C in the institutional biobank. For ELISA, aliquots were thawed once and cleared by brief centrifugation; samples with visible hemolysis, lipemia, or icterus were avoided. All oxidative stress assays were performed from single freeze–thaw aliquots.
2.2.5. Assays & Units
Malondialdehyde (MDA) was quantified by ELISA and is reported in μmol/L equivalents derived from kit units (ng/mL) using the molecular weight of malondialdehyde (72.06 g/mol). Raw ng/mL values are available on request. For comparability with prior literature, we also provide µmol/L equivalents using the molecular weight of malondialdehyde (72.06 g/mol): µmol/L = (ng/mL) ÷ 72.06 (since 1 ng/mL = 1 µg/L and 1 µmol/L = 72.06 µg/L). Example: 180 ng/mL ≈ 2.50 µmol/L.
2.2.6. Etiology and Medication Exposure
Etiology of cirrhosis was abstracted from the electronic medical record and hepatology notes and classified as alcoholic, viral (HBV and/or HCV), MASLD (metabolic dysfunction–associated steatotic liver disease), mixed (≥2 etiologies), or other/cryptogenic. When multiple etiologies were documented, cases were labeled mixed; when etiology could not be ascertained reliably, cases were labeled cryptogenic.
Medication exposure was captured at admission and within 48 h (or up to the time of serum sampling, if earlier) for agents known to influence oxidative stress or encephalopathy course: lactulose, rifaximin, diuretics (spironolactone and/or furosemide), intravenous albumin, statins, and antioxidants. Exposures were recorded as present/absent; denominators reflect available data where occasional missingness occurred.
Terminology and classes. Throughout the manuscript, Child–Pugh class refers to the conventional categories B and C derived from the original Child–Pugh score.
Severity definitions and operationalization: Hepatic encephalopathy (HE) was categorized as mild (West Haven 0–I; includes absent), moderate (West Haven II), and severe (West Haven III–IV). Ascites was graded as: grade 1 = mild (often detectable only by ultrasound), grade 2 = moderate, and grade 3 = severe/tense. Throughout the manuscript, both HE and ascites are treated as three-level ordinal variables and reported as mild, moderate, and severe. Where a binary sensitivity analysis is presented for ascites, it is explicitly labeled severe/tense (grade 3) vs. non-tense (grades 1–2) or present vs. absent, as appropriate.
Severity scores: In addition to Child–Pugh class, we computed the MELD-Na score using the OPTN/UNOS algorithm with standard bounds (bilirubin, INR, and creatinine values < 1.0 set to 1.0; creatinine capped at 4.0 mg/dL; serum sodium bounded to 125–137 mmol/L; natural logarithms used). Dialysis status within 7 days was not systematically captured in this retrospective extraction; therefore, the dialysis override was not applied. We did not calculate MELD 3.0 because sex was not available in the analytic spreadsheet; this is acknowledged as a study limitation.
2.3. Statistical Analysis
Statistical analyses were performed using IBM SPSS Statistics v. 26.0 (IBM Corp., Armonk, NY, USA). For descriptive analysis, continuous variables were reported both as mean ± standard deviation and median with interquartile range, depending on distribution. Categorical variables were expressed as counts and percentages. Sample size: No a priori sample-size calculation was performed; the cohort size (n = 90) was determined by the availability of eligible biobank cases in the study window. Analyses are framed as exploratory.
Sample size and power: No a priori power calculation was performed due to the retrospective design. As a reference, detecting small-to-moderate effects in χ2 comparisons typically requires substantially larger samples than available here; therefore, the present analyses are hypothesis-generating and precision is limited.
The normality of continuous variables was tested with the Shapiro–Wilk test and visual inspection. Group comparisons employed the Mann–Whitney U test for non-normal continuous data and the Chi-square test for categorical data. Associations between oxidative stress biomarkers (MDA, 8-iso-PGF2α) and both clinical severity scores (Child–Pugh, encephalopathy, ascites) and laboratory parameters (albumin, INR, bilirubin, creatinine) were examined using Spearman’s rank correlation coefficient.
A simplified composite score was developed to evaluate the joint predictive value of age and oxidative stress on cirrhosis severity. Patients older than 60 years and with MDA ≥ group median (µmol/L) were assigned two points; those meeting one or none of these criteria received 1 or 0 point(s). The association between this composite score and clinical severity (Child–Pugh B vs. C; severe encephalopathy [grade 3] vs. grades 1–2) was evaluated using the Chi-square test. This composite score was conceived as an exploratory, hypothesis-generating tool and not as a validated clinical model. Statistical significance was set at two-tailed p < 0.05, with 95% confidence intervals reported for key estimates.
2.4. Ethical Considerations
According to the European Union Guidelines (Declaration of Helsinki), the study received the approval of the Institutional Ethics Committee of the University of Medicine and Pharmacy of Craiova (registration no. 225/27 August 2024). In our institution, patients provide written broad consent at admission for biobanking and future research use of de-identified samples and clinical data; only cases with valid consent were eligible. No additional procedures were performed for the present study.
4. Discussion
The results obtained in this study highlight a severe clinical profile of liver cirrhosis among the analysed patients, characterised by a predominance of Child–Pugh B and C grades, with an increased frequency of complications such as hepatic encephalopathy and severe ascites. The age distribution of patients revealed relevant clinico-biological differences, particularly in the advanced age groups, where higher INR and bilirubin levels were observed, in parallel with a decrease in serum albumin, all indicating progressive liver damage. These findings are consistent with recent literature, which emphasises worsening of liver function with advancing age and accumulation of comorbidities [
24].
Although the values of oxidative stress markers (MDA and 8-iso-PGF2α) were elevated in most cases, direct correlations with liver severity parameters did not reach statistical significance. This finding is consistent with international evidence, where these biomarkers have shown heterogeneous and often inconsistent associations with clinical severity in decompensated cirrhosis. Reporting such negative results remains valuable, as it refines current understanding and delineates the limited prognostic utility of these markers. Previous studies have suggested possible links between MDA and parameters of liver or neurocognitive dysfunction [
25], but our results indicate that such associations could not be consistently demonstrated in this cohort. Importantly, our data showed that MDA levels increased significantly with encephalopathy severity (
p = 0.021), suggesting that systemic oxidative stress may contribute to neuropsychiatric impairment in cirrhotic patients.
The markers utilised in our analysis—malondialdehyde (MDA) and 8-iso-PGF2α—have been frequently proposed in the literature as biomarkers of lipid peroxidation and systemic inflammation associated with liver dysfunction. Zheng et al. reported an association between elevated MDA levels and reduced grey matter volume in nonalcoholic cirrhosis, suggesting a relationship between oxidative stress and neurocognitive impairment observed in hepatic encephalopathy [
14]. Experimental and clinical studies in recent years confirm that oxidative stress contributes to mitochondrial dysfunction, hepatic stellate cell activation and fibrogenesis, and is involved in the transition from steatohepatitis to cirrhosis and subsequently to hepatocellular carcinoma [
24,
26]. In an analysis of patients with metabolic liver disease, Ma et al. identified MDA as a relevant marker for the severity of liver damage in NAFLD and NASH, with a significant association between its levels and histological scores of inflammatory activity [
26]. Delli Bovi et al. have also proposed the integration of MDA into risk stratification algorithms, given its correlation with systemic proinflammatory status [
27]. 8-iso-PGF2α, although less widely used in current practice, is recognised as a specific biomarker for lipid oxidative stress, being detected in increased concentrations in patients with advanced liver damage, but with high interindividual variability [
28,
29]. A recently published prospective study showed that elevated levels of 8-iso-PGF2α in urine may predict the risk of hepatocarcinoma among patients with chronic liver disease. However, the clinical applicability of this marker remains to be validated [
30]. In our study, neither MDA nor 8-iso-PGF2α levels differed significantly between Child–Pugh classes or across categories of ascites severity. These negative findings emphasise that oxidative stress markers appear to have limited value for staging cirrhosis severity in decompensated patients.
An original contribution of this study is the formulation and testing of a simplified composite score based on the association between age > 60 years and elevated MDA values (≥2.41 μmol/L). This score was significantly associated with clinical severity, being more common in Child–Pugh class C patients. These results suggest that biological ageing, together with systemic oxidative stress, may synergistically contribute to hepatic decompensation. However, since the score was derived and tested within the same cohort, it must be regarded as exploratory. External validation in larger, prospective cohorts is required before any clinical applicability can be considered. The idea of combining these parameters is supported by well-documented pathophysiological premises [
24,
28]. The Age + MDA composite was conceived as a minimal, hypothesis-generating signal-finding tool. In our cohort, age and MDA were not correlated (Spearman ρ = −0.09;
p = 0.42;
n = 90), suggesting complementary rather than redundant information; nonetheless, effect sizes were small, no internal validation was performed, and the composite is not intended for clinical use.
The analysis performed in this study showed that patients with age > 60 years and elevated MDA values were significantly more likely to be classified in Child–Pugh score class C than those without both factors. This association suggests that the synergy between age and oxidative stress may contribute to accelerated liver decompensation, overriding the influence of each factor individually. Interestingly, neither MDA nor age alone had a robust predictive power, but the combined score showed statistical significance, which reinforces the validity of this integrative model. Although the proposed score has a simple construction, its advantage lies in its feasibility for clinical application without requiring advanced testing or complex calculations. Thus, this tool could be valuable in resource-limited clinical settings where rapid risk stratification is required. Previous studies have suggested the usefulness of composite scores based on biological and age parameters in other liver pathologies. However, most of them have focused on extended scores (e.g., MELD or complex biochemical modelling) [
27,
31]. At the same time, it should be noted that validation of the score in a small sample and a retrospective design limits general conclusions about its applicability. However, the results obtained support the utility of exploring this approach in future studies, preferably prospective, including correlations with long-term outcome, survival, and the need for liver transplantation.
Taken together, our findings provide clinically useful insights. Oxidative stress biomarkers did not add discriminatory power for prognostic stratification by Child–Pugh class or ascites, but MDA was associated with encephalopathy severity. These results highlight that oxidative stress markers should not be applied indiscriminately for staging, yet they may have a role in predicting or monitoring specific complications where conventional scores are less granular.
The present study should also be interpreted in the light of methodological limitations which, although inherent to a retrospective design, may influence the generalisability of the results. Firstly, the sample size analysed was relatively modest, which may reduce the statistical power of the tests applied, especially in the context of subgroup analyses or exploratory evaluations. This limitation is particularly relevant in the case of relationships between oxidative stress markers and clinical severity scores, where the observed differences were often suggestive but not always supported by statistical significance. It should also be noted that the patients included in the study presented with liver cirrhosis of heterogeneous aetiology, without a clear stratification according to cause (viral, alcoholic, metabolic, etc.). This lack of etiological homogeneity may be a source of variability in oxidative response and clinical severity, potentially influencing the relationships identified in the analysis. At the same time, the cross-sectional nature of the study does not allow us to assess the predictive value of MDA and 8-iso-PGF2α markers on long-term outcome, complications, or survival, but only to explore a possible correlation at the time of clinical evaluation. As for the proposed composite score, it was derived and tested in the same group of patients without an external validation step. Even if the results obtained are promising, statistical overcorrelation cannot be excluded, and the applicability of the score in other populations remains unproven. Also, the interpretation of oxidative stress marker values should be made with caution, considering the possible influences of other systemic clinical conditions or treatments administered, which could not be fully controlled in this retrospective design.
We report MELD-Na; MELD 3.0 was not computed because sex was not recorded in the analytic dataset, although albumin and other components were available. This omission is unlikely to change the main conclusions but is acknowledged as a limitation.
The results provide preliminary, hypothesis-generating support for a link between oxidative stress, age, and the severity of liver decompensation. The simplicity of the proposed score and the feasibility of its application in practice justify further research in this direction. Prospective studies in larger and homogeneous cohorts could clarify to what extent such simple but integrated scores can contribute to risk stratification and to predicting the clinical course of patients with liver cirrhosis.
The role of oxidative stress in liver diseases has been thoroughly examined, with research highlighting the influence of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the development of conditions such as ARLD, non-alcoholic fatty liver disease (NAFLD), viral hepatitis, and hepatocellular carcinoma (HCC) [
5,
9].
The liver serves as the primary location for alcohol metabolism and is among the initial sites affected by alcohol-induced injuries. In ARLD, the metabolic processing of alcohol necessitates the activation of the cytochrome P450 2E1 (CYP2E1) isoform, which is responsible for the generation of reactive oxygen species (ROS). Reactive oxygen species (ROS) can interact with fatty acids derived from lipids, leading to the formation of various peroxides. These compounds can interact with proteins and DNA, forming adducts that lead to structural and functional changes in liver cells, ultimately resulting in cell death signaling. The alternative liver processing of alcohol via the alcohol dehydrogenase reaction produces acetaldehyde, a reactive intermediate that can interact with proteins and DNA, leading to the formation of adducts that exacerbate hepatocellular damage [
22].
Alcohol consumption modifies antioxidant systems responsible for the removal of reactive oxygen species via intricate signaling pathways. Ultimately, reactive oxygen species (ROS) can result in significant liver fibrosis and cirrhosis through the activation of hepatic stellate cells, which play a role in the accumulation of extracellular matrix in the liver [
12].
The alteration of the pro-oxidant/antioxidant balance was demonstrated in liver and blood samples of patients through various techniques, including direct quantification of reactive oxygen species (ROS) and reactive nitrogen species (RNS), identification of tissue storage of oxidative and nitrosative stress markers, measurement of lipid, protein, and DNA oxidation products, as well as assessments of individual antioxidants and total antioxidant capacity.
Interpretation for discordant HE associations (MDA vs. 8-iso-PGF2α). A plausible explanation for the discrepant behavior is both analytic and biological. Serum 8-iso-PGF2α measured by immunoassay is more susceptible to pre-analytical/assay variability (matrix effects, cross-reactivity) and often performs better when assessed as urinary isoprostanes or by LC/GC-MS reference methods. In contrast, MDA reflects a broader aldehyde burden from lipid peroxidation and protein adducts, which may track neurocognitive vulnerability more closely in decompensated cirrhosis. Additionally, in advanced disease, lipid peroxidation may plateau across clinical strata (ceiling effect), while heterogeneity in inflammation, cholestasis, renal function, nutrition, and medications can differentially influence these markers. Together, these factors can yield a detectable signal for MDA but a weaker gradient for serum 8-iso-PGF2α with respect to HE.
This study has several limitations. First, the stratification into four age classes was exploratory and not based on validated clinical thresholds, so results should be interpreted with caution. Second, information on cirrhosis etiology and concomitant therapies, including alcohol consumption, albumin, and statins, was incompletely available due to the retrospective design, which may influence oxidative stress profiles. The sample size was determined by case availability in the biobank, without a priori power calculation; therefore, findings should be interpreted as hypothesis-generating. Residual confounding. Etiology and medication exposures were incompletely captured and not fully standardized in this retrospective extraction; therefore, residual confounding cannot be excluded, and adjusted models were not pursued to avoid unstable estimates. Finally, no follow-up data were available, which prevented the evaluation of short- and long-term outcomes. Multiple non-hepatic and treatment-related drivers of oxidative stress (e.g., systemic inflammation/endotoxemia, alcohol use or recent withdrawal, cholestasis-related mitochondrial dysfunction, iron overload, renal dysfunction, sarcopenia/micronutrient deficits, intercurrent infections or GI bleeding, and drug exposures such as diuretics or dehydration from lactulose) may persist despite clinical stratification, potentially diluting biomarker–phenotype contrasts in this retrospective cohort.