#2897 Urinary CD44 levels in chronic kidney disease: a validation study

Abstract

Abstract Background and Aims Proteinuria is the one of the main cause of kidney failure progression. There is inadequate data about protein components in urine and CKD severity. Our recent urinary proteomics study demonstrated the higher expression of CD44 in the urine proteome of healthy participants compared to CKD patients, arguing the protective role of CD44 in kidney health. However, the validation study needed to proof those differences in CD44 levels by ELISA tests in healthy participants and CKD patients. Therefore, we aimed to investigate urinary CD44 levels in our previously studied cohort of healthy controls and CKD patients using ELISA test. Method This study included 49 healthy participants and 88 early-stage CKD patients. Along with routine laboratory tests, 24 h collected urine samples were investigated using liquid chromatography-mass spectrometry (HPLC-MS) for proteomic analysis. Exponentially Modified Protein Abundance Index (emPAI) was used to estimate peptide count of proteins. Additionally, urinary CD44 levels were measured using ELISA kit to validate findings from proteomic study. Results A brief baseline characteristics of study population presented in Table 1. CKD group represented with lower eGFR, increased creatinine and higher proteinuria compared to healthy controls. Urinary CD44 levels were significantly higher in CKD group compared to healthy controls. Both CD44 levels measured by HPLC-MS and ELISA methods significantly positively correlated with eGFR levels (Table 2). Conclusion In this validation study, we compared the levels of CD44 measured by HPLC-MS and ELISA in healthy controls and CKD patients. We demonstrated that CD44 is overexpressed in urine samples of healthy people compared to CKD patients and may play a protective role in the kidney health. Further investigations needed to explain this finding in a different cohort and large number of CKD patients.