Relationship between serum free fatty acid and cytokines, carotid atherosclerosis in chronic kidney disease

Abstract

To investigate the serum level of free fatty acid (FFA) and explore its relationship with cytokines and atherosclerosis (AS) in chronic kidney disease (CKD). The serum level of FFA was determined with enzymatic colorimetry. IL-1β, IL-6 and TNFα were determined with ELISA. High-sensitivity C-reactive protein (hsCRP) was measured with immunoturbidimetry. Prevalence of atherosclerosis was detected with carotid ultrasonography. We evaluated the relationship between serum levels of FFA and IL-1β, IL-6, TNFα, hsCRP as well as the renal function in 130 adult patients with CKD, stratified according to the GFR (based on the National Kidney Foundation/Kidney Dialysis Outcomes Quality Initiatives) and in 58 hemodialytic (HD) patients. The relationship between FFA level and cardiac geometry incidence in CKD patients was analyzed with logistic regression model. The serum level of FFA was significantly higher in CKD patients as compared with that in the healthy controls [(492.63±143.59) vs (302.65±142.18) µmol/L, P<0.01], even in the early stage of CKD. The level of FFA increased with the progression of renal dysfunction. In the non-dialytic CKD group, the level of FFA was negatively related to GFR and positively related to the proteinuria (P<0.05), while in the HD group, it was positively correlated with dialysis duration (P<0.05). The serum levels of FFA were higher in CKD patients with carotid artery atherosclerosis than those in patients without (P<0.05or<0.01). However, in both groups with impairment of renal function, the levels of FFA were positively correlated with hsCRP, IL-1β, IL-6, TNFα and TG (all P<0.05). A positive correlation between the level of FFA and the clinical manifestations such as carotid intimal medial thickness (IMT) and AS was also found. A negative correlation was found between the level of FFA and the serum level of albumin and GFR (P<0.05). Serum levels of FFA are significantly higher either in non-dialytic CKD or in HD patients and it is related with hsCRP, IL-1β, IL-6, TNFα as well as carotid artery atherosclerosis, indicating that FFA is an independent risk factor of AS in CKD.