Chronic kidney disease (CKD) is a global health burden, with uremic toxins (UTs) playing a central role in its pathophysiology. In this review, we systematically examined the evolution of UT classification from the 2003 European Uremic Toxin Work Group (EUTox) system based on molecular weight and protein-binding properties to the 2023 multidimensional framework integrating clinical outcomes, clearance technologies, and artificial intelligence. We highlighted the toxicity mechanisms of UTs across the cardiovascular, immune, and nervous systems and evaluated traditional (e.g., low-/high-flux hemodialysis) and advanced (e.g., high-cutoff dialysis and hemoadsorption) clearance strategies. Despite progress, challenges persist in toxin detection, clearance efficiency, and personalized therapy. Future directions include multi-omics-based biomarker discovery, optimized dialysis membranes, advanced adsorption technology, and AI-driven treatment personalization. This synthesis aims to bridge translational gaps and guide precision medicine in nephrology.

Background: Vascular calcification (VC) affects up to 90% of patients with end-stage renal disease and increases cardiovascular mortality 3- to 5-fold. Once considered passive mineral deposition, VC is now recognized as an active, toxin-driven process orchestrating vascular smooth muscle cell transdifferentiation, endothelial dysfunction, and matrix remodeling. However, current uremic toxin classifications remain biochemically oriented, providing limited clinical guidance for risk stratification and therapeutic selection. Methods: This comprehensive review reframes uremic toxin-driven VC through an integrated phenotypic lens, synthesizing molecular mechanisms, clinical biomarkers, and therapeutic targets into a unified translational framework. Results: We propose five mechanistic-clinical phenotypes representing distinct biological trajectories of vascular injury. These include (1) inflammatory-oxidative (dominated by indoxyl sulfate, p-cresyl sulfate, NLRP3 inflammasome activation), (2) mineral-metabolic (hyperphosphatemia, FGF23 excess, Klotho deficiency), (3) epigenetic-senescent (histone modifications, microRNA dysregulation, cellular senescence), (4) endocrine cross-talk (vitamin D, PTH, gut-derived metabolites), and (5) integrated toxic continuum (convergence of multiple pathways in advanced disease). A comprehensive biomarker panel spanning inflammatory markers, mineral metabolism parameters, epigenetic indicators, and endocrine-gut metabolites enables phenotypic stratification and therapeutic monitoring. Emerging therapies—including tissue-nonspecific alkaline phosphatase inhibition, ectonucleotide pyrophosphatase/phosphodiesterase 1 enzyme replacement, vitamin K₂ activation, senolytic agents, and SNF472 crystal-growth blockade—are mapped to their optimal phenotypic contexts. Conclusions: This phenotype-oriented paradigm transforms VC from an inevitable complication into a targetable and potentially reversible manifestation of uremic toxicity, establishing a translational foundation for precision-based vascular medicine in chronic kidney disease. The framework enables biomarker-guided patient stratification, rational therapeutic selection, and phenotype-enriched clinical trial design.

In patients with chronic kidney disease (CKD), cardiovascular events (CVA) are the main cause of morbidity and mortality. Vascular calcification, linked to bone mineral metabolism disorders such as elevated serum phosphate, parathyroid hormone (PTH), and FGF23, well-known uremic toxins, aggravate this risk. Calcimimetics are allosteric activators of the calcium-sensing receptor (CaSR), a G protein-coupled receptor that regulates PTH secretion and synthesis in response to changes in extracellular calcium in the parathyroid glands. Through direct and indirect mechanisms, they have demonstrated their efficacy in reducing the progression of vascular, valvular, and soft tissue calcification in experimental studies. Although clinical studies in dialysis patients did not achieve statistical significance in their primary objectives, positive results in subgroup analyses suggest that the lack of significance may be attributable to the short follow-up period. This finding highlights the need to consider early treatment strategies, especially in advanced stages of chronic kidney disease, to more effectively address the progression of vascular calcification through serum uremic toxins control.

In end-stage renal disease (ESRD), the accumulation of solutes normally excreted by the kidneys contributes to multiple complications, including vascular calcification (VC), a key factor in the heightened cardiovascular risk seen in these patients. Among VC drivers, hyperphosphatemia and the uremic milieu are major contributors. Kynurenine, a tryptophan metabolite classified as a uremic toxin, may further exacerbate this process. This study investigated whether kynurenine amplifies high phosphate (Pi)-induced calcification in human aortic endothelial cells (HAEC). Cells were treated with Pi and kynurenine for up to seven days. Kynurenine increased Pi-induced calcium deposition by 36%, accompanied by enhanced endothelial-to-mesenchymal transition (EndMT) and osteoblastic differentiation. Mechanistically, kynurenine activated the aryl hydrocarbon receptor (AhR) pathway, and pharmacological inhibition of AhR partially attenuated this effect. These findings suggest that kynurenine contributes to VC in ESRD by potentiating phosphate-induced endothelial dysfunction via AhR signaling.