Department of Clinical and Experimental Pharmacology, Faculty of Medicine, Slovak Medical University, Bratislava, Slovak Republic.
Kidney Blood Press Res. 2012;35(1):48-57. doi: 10.1159/000330349. Epub 2011 Aug 19.
P2X(7) receptors intervene with lymphocyte activation and are responsible for multiple processes, including calcium influx. Here, we studied the participation of P2X(7) receptors in disturbed intracellular calcium homeostasis regulation in early-stage chronic kidney disease (CKD).
The study involved 20 healthy volunteers and 20 CKD stage 2-3 patients. The free cytosolic calcium concentration (Ca(2+)) was measured using fluorimetry. The P2X(7) pore function was evaluated by the fluorescent dye ethidium bromide.
In peripheral blood mononuclear cells (PBMCs) of patients, Ca(2+), intracellular calcium stores and the capacitative calcium entry were increased when compared with healthy subjects. The agonist of P2X(7) receptor BzATP caused a sustained increase in Ca(2+) in both groups, but the effect was smaller in patients. The antagonist at the P2X(7) receptor KN-62 reduced Ca(2+) in patients, but had no effect in healthy subjects. In patients, the permeability of ethidium bromide through P2X(7) pores, as well as through BzATP-activated and KN-62-inhibited pores, was distinct from permeability in healthy volunteers.
These results demonstrate that the calcium signaling pathway in PBMCs of CKD patients is defective already in CKD stage 2-3, and the pore-forming P2X(7) receptors are involved in these pathophysiological processes.
P2X（7）受体参与淋巴细胞的激活，并负责多种过程，包括钙内流。在这里，我们研究了 P2X（7）受体在早期慢性肾脏病（CKD）中细胞内钙稳态调节紊乱中的作用。
本研究纳入 20 名健康志愿者和 20 名 CKD 2-3 期患者。使用荧光法测量游离细胞内钙浓度(Ca(2+))。通过溴化乙锭荧光染料评估 P2X（7）孔功能。
与健康受试者相比，患者外周血单核细胞（PBMCs）中的Ca(2+)、细胞内钙库和电容钙内流增加。P2X（7）受体激动剂 BzATP 引起两组Ca(2+)持续增加，但在患者中的作用较小。P2X（7）受体拮抗剂 KN-62 降低了患者的Ca(2+)，但对健康受试者没有影响。在患者中，溴化乙锭通过 P2X（7）孔以及通过 BzATP 激活和 KN-62 抑制的孔的通透性与健康志愿者不同。
这些结果表明，CKD 患者 PBMC 中的钙信号通路在 CKD 2-3 期就已经存在缺陷，并且形成孔的 P2X（7）受体参与这些病理生理过程。
