Shivam, Kumar

Scattered tubular-like cells (STCs) are dedifferentiated renal tubular cells that repair other damaged kidney cells. This study shows that renovascular disease (RVD) induces site-specific 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) modifications in DNA associated with transcriptional changes and impaired proliferative capacity of swine STCs, which could be mitigated in RVD-STCs treated with an epigenetic modulator. Therefore, our observations may contribute to the development of novel approaches to preserve the reparative capacity of STCs in individuals with RVD.

Abstract Background and Aims Almost 36 million US adults (1 in 7, 14%) suffer from chronic kidney disease (CKD), which is more prevalent in the elderly, affecting up to 34% of adults ≥ over 65. CKD has limited therapeutic options, partly due to the lack of large animal models that allow the translational study of the impact of age on CKD. This work reports the first preclinical model of CKD in naturally aged swine. Method CKD was induced in naturally aged (6-9 years old) and young (3 months old) domestic pigs (bilateral renal artery stenosis + high-cholesterol/high-carbohydrate diet), followed for 14 weeks, and compared to normal controls (n = 4–5/group). Renal hemodynamics were quantified in vivo by multidetector CT. Metabolic parameters, renal microvascular (MV) architecture (3D-micro-CT), and morphometric analysis (staining) were investigated ex vivo. Results Both young and old pigs developed CKD, but the renal and metabolic phenotype was accentuated in aging animals. We found that superimposition of aging on CKD resulted in higher triglycerides, glucose levels, insulin resistance, and adipose tissue accumulation (subcutaneous, visceral, perirenal) (Fig. 1A and B), accompanied by a more severe renal dysfunction (C), cortical MV rarefaction, and reduced peritubular capillary density (D and E), and more severe structural damage disclosed by increased glomerulosclerosis, tubule-interstitial fibrosis, and tubular injury (F). Notably, the severity of renal MV rarefaction in aging CKD correlated with functional and structural abnormalities (simple linear regression analysis, G). Conclusion Our study establishes the first large animal model of aging CKD, allowing the investigation of age as a biological variable in kidney-metabolic diseases. Age exacerbates metabolic and renal abnormalities, and our data support the critical role of renal MV disease in aging CKD and suggest that its exacerbation is a potential key player in its progression. This novel translational platform could foster new studies toward the elucidation of novel mechanisms of age-related deterioration of renal function in CKD and for developing therapeutic interventions.