Modulation of micro-rheological and hematological parameters in the presence of artificial carotid-jugular fistula in rats

BACKGROUND: Arteriovenous fistula (AVF) may affect erythrocytes through many pathways (e.g., mechanical, inflammatory). However, these effects haven't been elucidated completely yet. OBJECTIVE: To follow-up the hemorheological and the hematological changes in the presence of artificial carotid-jugular fistula in rats. METHODS: Female Wistar rats were subjected to sham-operated group (SG, n = 6) and to fistula group (FG, n = 10). Under general anesthesia, the right carotid artery and jugular vein were isolated via a neck incision, and in the FG carotid-jugular fistula was performed by microsurgical techniques. Hematological variables, red blood cell (RBC) deformability and membrane (mechanical) stability parameters were determined before operation and on the 1st and 6th postoperative weeks. Density separated samples ('young' and 'old' RBCs) were also tested. RESULTS: In FG group hematocrit, RBC and platelet counts increased gradually to reach highly significant level of increment on the 6th postoperative week. RBC deformability significantly was impaired. The membrane stability test showed lower deformability values after applying mechanical shearing. No significant differences were observed between density separated RBC subpopulations. CONCLUSIONS: The presence of arteriovenous fistula may lead to an increment of RBC mass and impairment of RBC deformability. These changes could be one of the pathways through which the fistula influences the microcirculation.