ESR 12: The role of vascular rarefaction in the progression of CKD: pharmacological targets of prevention
Supervisor: Ariela Benigni
PhD Student: Rayan Mahmoud
Experimental and clinical studies have provided the evidence that chronic kidney disease (CKD) progression can be delayed by drugs targeting renin angiotensin system (RAS). Studies performed at IRFMN demonstrated that regression of renal lesions after RAS blockade in MWF rats, a model of spontaneous CKD, was associated with robustly increased volume density of kidney blood vessels suggesting a regenerative process. The analysis of the glomerular capillary ultrastructure by scanning electron microscopy of glomerular casts revealed a larger fraction of glomeruli with increased capillary volume and length in response to ACE inhibitor (ACEi). The treatment also improved the peritubular capillary density.
Kidney vascular rarefaction and capillary loss play a pivotal role in the development of fibrosis in CKD. Thus, understanding the mechanisms underlying renal vessel remodeling and regeneration is crucial to identify key targetable molecular pathways for preventing renal disesase progression in CKD.
The general aim of the project is to elucidate the mechanisms underlying kidney vascular regeneration induced by RAS blockade in CKD and to identify the molecular mediators involved in the protective effects.
Studies will be peformed in MWF rats with advanced CKD treated with ACEi in the late stage of the disease to address the following specific aims:1)To explore whether ACEi restores glomerular microvasculature in the diseased kidney through a process called intussusceptive angiogenesis known to contribute to the glomerular tuft repair after injury, 2) To characterize the molecular signature of the microvascular endothelium during the disease and in response to ACEi treatment in order to identify differentially expressed genes regulating endothelial cell remodeling and regeneration; 3) to study the impact of ACEi on capillary endothelium ultrastructure.
- Intussusceptive angiogenesis will be assessed through the morphometric analysis of the glomerular capillary ultrastructure (intussusceptive pillars) on images of glomerular casts acquired using scanning electron microscopy.
- Isolation of microvascular endothelial from kidneys of MWF rats will be set up through positive selection of endothelial cells from a single cell suspension by magnetic separation.
- Transcriptomic analysis will be performed by single cell RNA sequencing in microvascular endothelial cells isolated from kidneys of untreated or ACEi-treated MWF rats and from healthy control kidneys.
- Changes in the expression of the identified molecular targets will be confirmed in kidney specimens through in situ hybridization or immunohistochemistry at mRNA or protein levels, respectively
- Mechanistic understanding of kidney vascular rarefaction and regeneration after RAS blockade in CKD;
- Identification of new druggable molecular targets to protect kidney vasculature and slow disease progression.