FP614
ALANYL-GLUTAMINE DECREASES CELLULAR INJURY AND ENHANCES CYTOPROTECTIVE RESPONSES IN ENDOTHELIAL CELLS DURING PD-FLUID EXPOSURE Free

INTRODUCTION: Vasculopathy, hypervascularization, and diabetes-like damage of vessels are important factors limiting long-term PD-therapy. The composition of all currently available PD-fluids leads to morphological and functional changes in the peritoneal membrane in adults and infants. During PD-fluid exposure, relevant cellular pathomechanisms might resemble those in hyperglycaemic diabetic conditions. This study focuses on proteomic characterization of endothelial cell injury and stress responses, with or without addition of the cytoprotective dipeptide alanyl-glutamine (AlaGln).

METHODS: Protein profiles of primary human umbilical vein endothelial cells (HUVEc) exposed to medium-diluted conventional PD-fluid with or without 8mM AlaGln were analysed by gel-based proteomics. Cell damage was assessed by quantification of lactate-dehydrogenase (LDH) release. Microdissected omental arterioles of children treated with conventional PD-fluids and age-matched controls with normal renal function were analysed with quantitative multiplex mass spectrometry (TMT-11plex LC-MS). In-vitro findings were related to PD-induced arteriolar changes based on abundance profiles of proteins identified in both proteomic analyses.

RESULTS: Marked cellular injury of HUVEc after PD-fluid exposure was associated with a molecular landscape of the enriched biological process clusters ‘glucose catabolic process’, ‘cell redox homeostasis’, ‘RNA metabolic process’, ‘protein folding’, ‘regulation of cell death’, and ‘actin cytoskeleton reorganization’ that characterize PD-fluid cytotoxicity and counteracting cellular repair process respectively. Addition of AlaGln to PD-fluid preserved endothelial cell integrity shown by significantly decreased LDH-release and by restored control levels of proteins in PD-fluid perturbed processes, especially enhancing protein folding capacity and response to stress. Comparison to human arterioles confirmed overlapping protein regulation between endothelial cells in-vitro and in-vivo, proving harmful effects of PD-fluids on endothelial cells leading to drastic changes of the cellular process landscape. Cellular damage and proteome changes in HUVEC were counteracted by AlaGln in-vitro.

CONCLUSIONS: In summary, this study shows harmful effects of PD-fluids also effecting endothelial cells and elucidates potential mechanisms by which AlaGln exerts cytoprotective effects in PD-induced endothelial cell damage, offering therapeutic targets to reduce side effects of PD.