Coagulation Cascade Activation Causes CC Chemokine Receptor-2 Gene Expression and Mononuclear Cell Activation in Hemodialysis Patients

Abstract

Priming of the coagulation cascade during hemodialysis (HD) leads to the release of activated factor X (FXa). The binding of FXa to its specific receptors, effector protease receptor-1 (EPR-1) and protease-activated receptor-2 (PAR-2), may induce the activation of peripheral blood mononuclear cells (PBMC) and promote a chronic inflammatory state that is responsible for several HD-related morbidities. In the attempt to elucidate the mechanisms underlying the coagulation-associated inflammation in HD, 10 HD patients were randomized to be treated subsequently with a cellulose acetate membrane (CA) and Ethylen-vinyl-alcohol (EVAL), a synthetic membrane that has been shown to reduce FXa generation. At the end of each experimental period, surface FXa and thrombin receptors (EPR-1 and PAR-1, -2, and -4) and CCR2 (monocyte chemoattractant protein-1 receptor) gene expression in isolated PBMC were examined. the ability of dialytic membranes to activate proteintyrosine kinases and the stress-activated kinase JNK and to modulate the generation of terminal complement complex (TCC) was also investigated. EPR-1 and PAR-2 and -4 mRNA expression, barely detectable in normal PBMC, were significantly upregulated in HD patients, particularly in those who were treated with CA. A striking increase of tyrosine-phosphorylated proteins and JNK activation was observed at the end of HD only in CA-treated patients. Simultaneously, an increased gene expression for both splicing isoforms of CCR2, A and B, only in PBMC from CA-treated patients was demonstrated. The increased CCR-2 mRNA abundance was followed by a significant increase in its protein synthesis. The high expression of CCR2 was associated with an increased generation of plasma TCC and a significant drop in leukocyte and monocyte count. By contrast, EVAL treatment slightly lowered TCC generation and normalized leukocyte count. In vitro FXa induced CCR2 A and B expression and JNK activation in freshly isolated PBMC. FXa-induced CCR2 mRNA expression was completely abolished by JNK and tyrosine kinase inhibition. In conclusion, these data suggest that subclinical clotting activation may cause an increased CCR2 gene and protein expression on uremic PBMC, contributing to HD-related chronic microinflammation. The use of the less coagulation-activating membrane, EVAL, may reduce PBMC activation through the modulation of the stress-activated kinase JNK.

Effect of Different Dialysis Modalities on Microinflammatory Status and Endothelial Damage

“…Furthermore, we have reported that dialysis modalities with high convective transport are capable of reducing but not normalizing the percentage of CD14 ϩ CD16 ϩ monocytes (13). During the HD process, the interaction of peripheral blood mononuclear cells with the dialysis membrane may activate the former, with consequent increased synthesis and release of proinflammatory cytokines (23,24). Our results may be partially explained by the greater ability of PD to remove high-molecular weight uremic toxins (25), although the potential role played by the contact between blood and foreign surfaces in the HD procedure should not be ignored.…”

Natural products inhibit LPS-induced activation of pro-inflammatory cytokines in peripheral blood mononuclear cells

“…In vitro and in vivo data suggest that cytokine production during HD is caused by (a) direct contact of leukocytes with dialysis membrane (Panichi et al, 2000;Pertosa et al, 1991), (b) active complement fragments generated during HD (Pertosa, Tarantino, Gesualdo, Montinaro, & Schena, 1993) and (c) back transport of bacterial derived material from the dialysate into the blood compartment (Bommer, Becker, & Urbaschek, 1996;Laude-Sharp et al, 1990). Complement activation during HD stimulates the transcription of cytokine genes, and a second stimulus with bacterial product facilitates the translation and secretion of cytokine proteins (Pertosa, Gesualdo, Bottalico, & Schena, 1995;Pertosa et al, 2005;Schindler, Lonnemann, Shaldon, Koch, & Dinarello, 1990).…”

Coagulation Activation Is Associated with Nicotinamide Adenine Dinucleotide Phosphate Oxidase-Dependent Reactive Oxygen Species Generation in Hemodialysis Patients

“…Moreover, the authors stated that heparin may act as a prooxidant agent increasing oxidative stress, but the use of unfractionated heparin has not been tested in this work (23). In a previous study, we demonstrated that subclinical clotting activation caused an increased CCR2 gene expression in uremic PBMCs; the use of EVAL improved this condition by reducing specific FXa and MCP-1 cell surface receptors (27). In this study we showed that patients treated with EVAL had significantly lower plasma levels of prothrombin F1 + 2, suggesting a low blood clotting activation.…”

“…Subclinical clotting activation contributes to HD-related chronic microinflammation, and thus the use of a less thrombogenic membrane, such as ethylene-vinyl-alcohol (EVAL), may improve this condition (27). EVAL is a synthetic polymer having both hydrophilic and hydrophobic segments.…”