Targeting immune–hemodynamic coupling in early diabetic kidney disease: Mechanisms, biomarkers, and therapeutic opportunities

Current diagnostic criteria for diabetic kidney disease (DKD) rely on moderately increased albuminuria (formerly microalbuminuria) or a persistent decline in estimated glomerular filtration rate (eGFR), both of which appear well after disease initiation. Substantial injury accumulates earlier, during a clinically silent phase characterized by glomerular hyperfiltration, endothelial dysfunction, and subclinical inflammatory remodeling. The dominant hyperfiltration model, anchored in tubular sodium–glucose handling and tubuloglomerular feedback, accounts for many features of early DKD, yet three observations are not fully accommodated within it: disease heterogeneity is more pronounced than tubular mechanisms alone can explain, residual hyperperfusion persists under optimized therapy, and the conversion of reversible hemodynamic stress into fixed structural injury remains poorly understood. We advance immune–hemodynamic coupling as a complementary and pharmacologically tractable framework. In this view, innate and adaptive immune activation, spanning macrophage polarization, dendritic cell maturation, Th1/Th17 skewing, complement engagement, and inflammasome signaling, reciprocally engages glomerular hemodynamics. The downstream consequences are tightly interlinked, comprising endothelial dysfunction, glycocalyx injury, an unbalanced nitric oxide/endothelin axis, tubuloglomerular feedback disruption, and maladaptive arteriolar remodeling. Human, experimental, and clinical evidence linking immune remodeling to hyperfiltration is synthesized, and biomarkers are mapped across four pathway domains (inflammatory, tubular, endothelial, and hemodynamic) to facilitate earlier risk stratification. Established and emerging interventions are evaluated within this framework, including renin–angiotensin–aldosterone system (RAAS) blockade, sodium–glucose cotransporter 2 (SGLT2) inhibitors, endothelin-targeted therapies, and inflammasome- or complement-directed strategies. Recasting early DKD as a coupled immuno-vascular disorder reveals a preclinical therapeutic window in which pathway-aligned biomarkers and rational combination pharmacotherapy could enable earlier and more effective intervention.