Sialic Acids in Kidney Disease: Immune Regulation, Complement Activation and Glomerular Injury.

Oxidative stress and inflammation are key drivers of kidney injury and disease progression. In this context, the role of sialic acids emerged as a critical regulatory layer linking redox imbalance, immune activation, and tissue damage. Sialic acids are terminal negatively charged residues that regulate complement activity, immune cell signaling, and the structural integrity of the glomerular filtration barrier. Alterations in sialylation, resulting from impaired biosynthesis or increased sialidase activity, disrupt immune homeostasis, enhance inflammatory responses, and promote complement-mediated injury. In the kidney, these mechanisms contribute to podocyte dysfunction, glomerular inflammation, and fibrosis and are implicated in glomerulopathies, transplantation, and plasma cell dyscrasias. Emerging evidence also highlights the therapeutic potential of targeting sialic acid metabolism through inhibition of desialylation or restoration of sialylation pathways. Overall, sialic acids represent dynamic modulators at the intersection of oxidative stress and immunity, offering novel opportunities for biomarker development and mechanism-based therapies in kidney disease.