Oxidative Stress Biomarkers in Pediatric and Early-Stage Type 1 Diabetes: Toward Redox Phenotyping.

Type 1 diabetes (T1D) is characterized by autoimmune β-cell destruction, metabolic instability, and long-term susceptibility to vascular and renal complications. Oxidative stress has been widely implicated in these processes, but it is often described as a generalized consequence of hyperglycemia, not as a measurable and heterogeneous biological state. In this review, we propose exploratory redox phenotyping as a framework for characterizing oxidative stress in pediatric and early-stage T1D. This approach integrates biomarkers of antioxidant defense, lipid peroxidation, protein oxidation, DNA oxidation, and inflammation-associated redox activity to explore potentially distinct patterns of redox dysregulation. Key biomarker domains include enzymatic antioxidant systems, lipid-peroxidation products, protein- and DNA-oxidation markers, and inflammatory mediators, which may collectively characterize the intensity, molecular compartment, and possible clinical relevance of redox dysregulation. Across pediatric presymptomatic T1D, newly diagnosed disease, partial remission, and short-duration established T1D, longitudinal redox profiling may help distinguish stage-specific or transient metabolic responses from persistent oxidative dysregulation. These clinical phases are considered separately as they differ in immune activity, residual C-peptide secretion, glycemic exposure, and biological susceptibility. Redox phenotyping may also improve the design of antioxidant, mitochondrial, anti-inflammatory, and NRF2-targeted interventions by enabling biomarker-based patient selection. By defining oxidative stress as a stratifiable biological domain, this framework may advance precision risk assessment and guide more rational, targeted redox-directed therapies for children and individuals with early-stage T1D. At present, these proposed profiles remain hypothetical and require validation in prospective cohorts using standardized assays, reproducible thresholds, and clinically meaningful outcomes.