FC 109GLUCOSE DERIVATIVE INDUCED VASCULOPATHY IN CHILDREN ON PERITONEAL DIALYSIS
Authors: Bartosova Maria , Schaefer Betti , Zhang Conghui , Herzog Rebecca , Ridinger David , Damgov Ivan , Lévai Eszter , Marinovic Iva , Eckert Christoph , Romero Philipp , Sallay Peter , Ujszaszi Akos , Unterwurzacher Markus , Wagner Anja , Hildenbrand Georg , Warady Bradley , Schaefer Franz , Zarogiannis Sotirios G , Kratochwill Klaus , Schmitt Claus 
Published: May 2021

Abstract

Background and Aims
Patients with chronic kidney disease patients (CKD) have an exceedingly high cardiovascular risk. While vasculopathy is further accelerated during peritoneal dialysis (PD), the pathophysiological role of reactive metabolites such as glucose degradation products (GDP) is uncertain.

Method
Omental and parietal peritoneal tissues from 100 non-CKD individuals, 107 children with CKD5, 60 children treated with neutral pH, low GDP, and 30 children treated with acidic pH, high GDP PD fluids underwent standardized digital histomorphometry. Omental arterioles localized within the fat tissue, protected from direct PD fluid exposure were microdissected for multi-omics analysis. Key regulated pathways were validated by quantitative immunostaining, with localization microscopy in peritoneal tissues of matched cohorts and in vitro in human umbilical vein endothelial cells.

Results
Arterioles from children with CKD5 exhibited reduced lumen to vessel ratio (L/V) and reduced endothelial telomere length compared to non-CKD individuals; gene ontology analysis identified enrichment of arteriolar genes associated with nuclear telomere cap complex and focal adhesion. Pathway analysis of arteriolar cross-omics identified top canonical pathways including telomere extension by telomerase, actin cytoskeleton, integrin and tight junction signalling.
Peritoneal vasculopathy progressed with PD vintage and was more pronounced with high versus low GDP exposure (p&lt;0.001). Compared to CKD5, low GDP-PD upregulated 145/110 and downregulated 38/34 arteriolar genes/proteins, high GDP-PD upregulated 684/137 and supressed 1560/55 genes/proteins (p&lt;0.01). High GDP milieu induced upregulation of arteriolar genes involved in cell death/apoptosis and suppressed genes related to cell viability/survival, cytoskeleton organization and immune response biofunctions. Vasculopathy associated canonical pathways concordantly regulated on arteriolar gene and protein level with high GDP exposure included cell death/proliferation, apoptosis, cytoskeleton organization, metabolism and detoxification, cell junction signalling, and immune response.
Quantitative validation in PD cohorts with similar PD vintage, dialytic glucose exposure and age (n=15 / group) verified increased proapoptotic activity and cytoskeleton disintegration with high-GDP exposure; single-molecule-localization microscopy demonstrated arteriolar endothelial zonula occludens-1 (ZO-1) disruption. Absolute and relative to endoluminal surface length, arteriolar endothelial cell counts were inversely correlated with GDP exposure, with apoptosis marker caspase-3, TGF-ß induced pSMAD2/3, interleukin-6, ZO-1 protein abundance and the degree of vasculopathy. In vitro, exposure to GDP 3,4-dideoxyglucosone-3-ene dose-dependently reduced nuclear endothelial lamin-A/C and membrane ZO-1 assembly. Transendothelial electrical resistance was decreased. ZO-1 and sealing tight junction claudin-5 protein abundance were decreased in cells after incubation with high GDP compared to low GDP PD fluid and culture media. On nanoscale level GDP reduced junction cluster formation in the membrane area.

Conclusion
Multi-omics analysis of omental arterioles from children without pre-existing vasculopathy and life-style related confounders identified key mechanisms of vascular aging in CKD5 and the major contribution of GDP to accelerated vasculopathy during PD, i.e. disruption of endothelial cell junctions and cytoskeleton and induction of apoptosis.