Expression of purinergic P2X 7 receptors in subpopulations of peripheral blood mononuclear cells in early-stage of chronic kidney disease.

Chronic kidney disease (CKD) is known as a state of chronic low-grade inflammation, enhancing cardiovascular risk and immunodeficiency. Purinergic signaling has been accepted as a crucial component in the pathogenesis of various diseases, mediating a vast array of biological processes. The P2X7 receptor is one of the important cell surface regulators of several key inflammatory molecules. The aim of the study was to examine the expression of surface P2X7 receptors in subpopulations of peripheral blood mononuclear cells (PBMCs), and to evaluate the promising prognostic markers of inflammation (neutrophil/lymphocyte, Ne/Ly ratio) and cardiovascular risk (monocyte/high density lipoprotein cholesterol, Mo/HDL ratio) in early-stage CKD. The study involved 15 healthy volunteers and 15 non-diabetic patients with CKD stage 2 - 3. PBMCs were isolated from heparinized blood by Ficoll gradient centrifugation. To determine the expression of P2X7 receptors in different subpopulations (CD14+ monocytes, CD3+ T-lymphocytes and CD19+ B-lymphocytes), the cells were stained with FITC-conjugated anti-P2X7 . The monocyte, lymphocyte and neutrophil counts were measured in whole blood as a part of routine hemogram. The number of T- and B-lymphocytes was determined by flow cytometry using antibodies anti-CD3-PE and anti-CD19-PE, respectively. The expression of surface P2X7 receptors was 1.4 fold increased in PBMCs of CKD patients compared to healthy volunteers. The expression of P2X7 receptors was 2.1 fold higher in monocytes and 1.5 fold higher in the whole lymphocyte population, with significant increase only in B-cells. The monocyte count, as well as the Ne/Ly and Mo/HDL ratios were also significantly increased. In conclusion, the increased P2X7 receptors expression in monocytes, the monocyte count and the Ne/Ly ratio are manifestations of chronic inflammation already in early stages of CKD. The study also supports recent findings that the Mo/HDL ratio could be used as additional parameter for monitoring cardiovascular risk profile in these patients.