A Proposed Selenium Deficiency Staging Framework: SELENOP-Guided Clinical Staging of Selenoprotein Reserve Depletion Across High-Metabolic End-Artery Tissues — From Subclinical to Multi-Organ Vulnerability

[SUPERSEDED — This is a duplicate upload. The canonical version of this paper is available at https://doi.org/10.5281/zenodo.20563307] This paper proposes a four-stage clinical selenium deficiency framework based on SELENOP saturation kinetics and organ-specific vulnerability hierarchy: Stage 0 (Adequate: SELENOP at saturation ≥5 mg/L); Stage 1 (Subclinical insufficiency: SELENOP 3.5-5 mg/L, pulmonary and renal GPx partially reduced); Stage 2 (Functional deficiency: SELENOP 2.0-3.5 mg/L, deiodinase T4-to-T3 conversion impaired); Stage 3 (Multi-organ deficiency: SELENOP below 2.0 mg/L, all selenoprotein systems compromised). A 2025 Berlin Aging Study II analysis (n=1,568) confirmed that low SELENOP and GPx3 are associated with accelerated biological aging measured by DNA methylation clocks. The SUSTAIN CSX trial confirmed GPx3 activity predicts 6-month survival (AUC 0.73) in cardiac surgery patients. All claims are hypothesis-level.