Studying the spatial neuroinflammatory profile and BBB disruption in a kidney injury mouse model

Abstract

Chronic Kidney Disease (CKD) is a prevalent condition characterized by progressive kidney dysfunction, leading to systemic retention of toxic metabolites called Protein-Bound Uremic Toxins (PBUTs). CKD patients face significantly higher risk of experiencing neurological complications, such as cognitive impairment and cerebrovascular disease. We hypothesize that understanding the pathological role of PBUT accumulation in neuroinflammation and Blood-Brain Barrier (BBB) dysfunction phenomena is crucial to elucidate CKD-associated neurological pathologies. In this study, we used a mouse model of kidney injury induced by renal ischemic reperfusion injury (rIRI) as a proxy for CKD, we investigated the applicability of the model, and we established a methodological framework to study the potential impact of PBUTs on neuroinflammation and BBB disruption. LC-MS analysis was used to quantify PBUT serum concentrations in control (Sham) and IRI mice. Additionally, the mouse brains were harvested and processed into formalin-fixed paraffin-embedded (FFPE) blocks and sliced for immunofluorescence experiments. We then validated methods to study microglial activation, by using different markers (i.e., IBA-1 and P2Y12) as well as computational analysis of microglial morphology. To assess the structural and functional integrity of the BBB, we stained for laminin, a crucial component of the vascular basement membrane as well as GFAP and Aquaporin 4 (AQP4), both astrocytic markers that can give us valuable information about astroglial reactivity and BBB integrity. Our study lays the groundwork for investigating the neurological effects of PBUTs in the context of kidney injury.