Hyperchloremia as a Terrain Signal: A Systems Physiology Model Linking Hydration, Bile Signaling, Taurine, and the Vertical Regulatory Axis of Chloride-Dominant Acid–Base Terrain Lantern of Sulfur, Vertical Terrain Axis, Version 12 (March 2026)

Persistent hyperchloremia accompanied by non–anion-gap metabolic acidosis (NAGMA) is commonly interpreted as a secondary electrolyte disturbance arising from renal transport behavior. However, chloride participates directly in renal sensing, vascular regulation, and circulatory signaling through macula densa pathways, RAAS activation, and tubular ion transport. This paper proposes a systems physiology framework in which chloride-dominant acid–base patterns are interpreted as signals emerging from a vertically organized regulatory architecture linking circadian timing, hydration state, bile signaling, vascular nitric oxide tone, RAAS interpretation, and renal transporter execution. Within this structure, the kidney functions primarily as an execution layer translating upstream regulatory conditions into electrolyte transport outcomes. In this model, hyperchloremia represents a terrain signal reflecting upstream regulatory interpretation rather than primary renal dysfunction. Hydration dynamics and bile signaling are examined as upstream influences capable of shifting chloride–bicarbonate balance before overt cardio-renal disease appears. Taurine is discussed as a cross-axis stabilizing molecule intersecting osmotic regulation, bile acid conjugation, vascular signaling, and renal physiology. The framework integrates chloride physiology, hydration regulation, and cardiovascular expression into a unified regulatory axis and generates testable hypotheses regarding chloride-dominant terrain states in systemic physiology. Related work in this research series Additional preprints examine mechanistic components and clinical expression of the proposed regulatory architecture, including the hydration–bile regulatory axis, buffering failure in chloride-dominant acid–base states, cross-axis stabilizing molecules such as taurine, and clinical analyses of hyperchloremia and cardio-renal physiology in heart failure. Reversible HFrEF: The Pattern Five Specialties MissedLantern of Sulfur, Concept A′ v12.4Clinical analysis of reversible heart failure patterns linked to chloride-dominant electrolyte terrain and regulatory misinterpretation.https://zenodo.org/records/18929935 Chloride–Bicarbonate Terrain Shifts in Electrolyte Regulation (KICO Model)Lantern of Sulfur, Concept A v12.1Systems hypothesis linking metabolic rhythm, RAAS activation, and chloride-dominant acid–base terrain.https://zenodo.org/records/18930064 Circadian and Metabolic Timing in Electrolyte RegulationLantern of Sulfur, Concept A v12.1A coupled clock model examining how circadian rhythm and metabolic timing influence chloride terrain signals and cardiovascular stress.https://zenodo.org/records/18930159