Abstract Body: Chronic kidney disease (CKD) is associated with a mineral imbalance that promotes osteogenic remodeling and medial arterial calcification (MAC). Although phosphate-driven vascular calcification has been extensively studied, the temporal relationship between early vascular senescence and detectable mineral deposition remains incompletely defined in vivo. In the present study, we examined whether markers of vascular senescence and inflammatory signaling arise before detectable calcification in an early-stage CKD model.
Male Sprague–Dawley rats were fed an adenine diet to induce early-stage CKD. In contrast, a separate adenine plus vitamin D3 regimen served as a benchmark condition, producing robust vascular calcification. Aortic calcification was assessed using micro-computed tomography and Alizarin Red staining. Senescence markers were evaluated using SA-β-galactosidase activity quantified by C12FDG flow cytometry in CD45-negative vascular cells and by quantitative PCR analysis of p19 and p21 expression. NLRP3 immunostaining and inflammatory cytokines (IL-1β and IL-6) were examined to assess inflammasome-associated inflammatory signaling. Expression of the phosphate transporter PiT-1 was also evaluated.
Despite the absence of detectable calcification in early-stage CKD animals, aortic tissue demonstrated increased SA-β-gal activity and elevated p19 and p21 expression. To examine whether mineral stress alone could induce similar early phenotypes in intact vascular tissue, aortic rings were cultured under high-phosphate conditions for five days. During this short-duration exposure, rings remained non-calcified but exhibited increased SA-β-gal positivity, elevated NLRP3 immunostaining, increased IL-1β and IL-6 secretion, and increased PiT-1 expression. Treatment of phosphate-primed rings with soluble EDTA reduced PiT-1 expression, suggesting that early phosphate-transporter induction may be modifiable during this priming interval.
Together, these findings define a measurable pre-calcific vascular priming state in CKD characterized by increased senescence markers and inflammasome-associated inflammatory signaling before overt mineral deposition. These observations support the concept that mineral imbalance may be associated with early vascular remodeling events that precede irreversible calcification.