Plasma C-Terminal Agrin Fragment (CAF) as an Early Marker for Kidney Function in Patients with Chronic Kidney Disease

Abstract
Background: CKD is defined by the presence of renal damage or impaired renal function for three or more months, irrespective of the cause. The presence of the damage or impaired function for at least three months is important to distinguish CKD from AKI. C-terminal Agrin Fragment (CAF) was found in the basement membrane of the kidney and cleared from circulation by glomerular filtration.
Aim of Study: To evaluate plasma level of C-terminal agrin fragment as an early detector of renal function impairment in patients with chronic kidney disease.
Methods: The study was carried on two groups Group (I): 20 healthy persons as a control group and Group (II): 60 CKD patients. Patients were selected from Internal Medicine Department, Tanta University Hospital. We excluded patients suffered from inflammatory, autoimmune, infectious disorders and malignant diseases, also patients with acute underlying illness were excluded from the study. Informed consents were taken from all participants and the privacy of the data were greatly considered. Complete clinical examination including: Body Mass Index (BMI) calculation and routine laboratory investigations including Complete Blood Count (CBC), blood urea, serum creatinine, eGFR, 24h proteinuria, sodium and potassium, CRP and specific investigation: Plasma level of C-terminal Agrin Fragment (CAF) measurements by ELISA technique was done.
Results: Plasma CAF showed statistical significance increase in patients group than control healthy groups (p<.001) with gradual increase in its level in progressive CKD stages. There was significant positive correlation between plasma CAF, serum creatinine and blood urea (p<.001) while there was significant negative correlation between plasma CAF and eGFR (p<.001). There was significant increase in CAF in early stage 1 CKD group compared to control group (p<.001). Plasma CAF wasn't affected by age, sex and muscle mass in contrast to creatinine which was affected by them.
Conclusion: The results of this study showed that plasma CAF was increasing with the progression of CKD stages and it was more sensitive and specific than serum creatinine, blood urea and eGFR in estimation of staging CKD. Plasma CAF also can differentiate between healthy individuals and stage 1 CKD patients, so measurement of plasma level of CAF may represent a promising bio-marker of early kidney damage detection and progression to ESKD.