Proinflammatory CD14+CD16+ monocytes are associated with vascular stiffness in predialysis patients with chronic kidney disease

BACKGROUND Chronic inflammation is frequently noted in patients with chronic kidney disease (CKD) and contributes to the development and progression of cardiovascular diseases. Monocytes are heterogeneous populations of cells, and they can be divided into subtypes with different phenotypes and functions based on CD14 and CD16 positivity. This study examined whether the proinflammatory CD14(+)CD16(+) monocyte subset expands in predialysis CKD patients, and also whether the expansion of these cells is closely associated with systemic inflammation and cardiovascular risk factors. METHODS The percentages of proinflammatory CD14(+)CD16(+) monocytes were analyzed in 111 predialysis CKD patients using a flow cytometer, and they were compared with brachial-ankle pulse wave velocity as well as the cytokine plasma levels and other clinical parameters. RESULTS The proportion of CD14(+)CD16(+) monocytes was significantly higher in patients with advanced stages of CKD than in patients with the early stages. Interleukin-6 levels were also high in patients with advanced stages of CKD. The expansion of CD14(+)CD16(+) monocytes showed significant positive correlations with the high-sensitive C-reactive protein levels, and negative correlations with the levels of serum albumin, hemoglobin, and 25(OH)-vitamin D. In addition, the expansion of CD14(+)CD16(+) monocytes was an independent factor correlated with brachial-ankle pulse wave velocity in diabetic CKD patients. CONCLUSION Expansion of the proinflammatory CD14(+)CD16(+) monocyte subset partially accounts for chronic inflammation, malnutrition, and atherosclerosis in CKD.