Serum amyloid A enrichment impairs the anti-inflammatory ability of HDL from diabetic nephropathy patients

Aims: Impaired anti-inflammatory ability of high-density lipoprotein (HDL) has been demonstrated in patients with type-2 diabetes mellitus (T2DM). However, whether HDL from patients with diabetic nephropathy (DN) suffers additional damage remains unknown. This study compared the anti-inflammatory capacities of HDL from healthy controls, T2DM patients with normal renal function, and T2DM patients with DN. Materials and methods: HDL was isolated from healthy controls (n = 33) and T2DM patients with normal renal function (n = 21), chronic kidney disease (CKD) (n = 27), and end -stage renal disease (ESRD) (n = 27). Human peripheral blood mononuclear cells (PBMCs) from healthy volunteers were pretreated with HDL (100 mu g/mL) for 1 h, then incubated with lipopolysaccharide (LPS) (50 ng/mL) for 24 h. The anti-inflammatory ability of HDL was measured as the secretion of TNF-alpha in LPS-activated monocytes. Results: The anti-inflammatory ability of HDL was gradually impaired as kidney function declined. Serum amyloid A (SAA) concentration in HDLDN significantly increased and was positively correlated with the impaired anti-inflammatory ability of HDL (Pearson r = 0.315, P = 0.006). Furthermore, HDL supplemented with SAA significantly increased TNF-alpha release from PBMCs compared with that from control HDL. Conclusions: These findings identified an impaired anti-inflammatory capacity of HDL from DN patients, which might be attributable to SAA enrichment. (C) 2017 Elsevier Inc. All rights reserved.