Abstract 3746: Circulating White Blood Cells Amplify Oxidative Stress in Congestive Heart Failure
A potential role for circulating white blood cells(WBC) as markers or mediators of oxidative stress in congestive heart failure(CHF) has so far not been investigated despite the ability of WBC to sense oxidative stress during a capillary passage and to react to it by increasing their free radical(FR) production. WBC were therefore isolated from arterial(A) or venous(V) blood samples of CHF patients (LVEF: 30±5%) and of controls(CON). WBC were incubated with a fluorescent CM-DCF probe, which selectively marks cytosolic FR, or with a fluorescent JC-1 probe, which is an indicator of mitochondrial membrane potential, or with a mito-ROS probe, which selectively detects mitochondrial FR production. WBC with significant fluorescence were identified by fluorescent associated cell sorter(FACS) and their number expressed as a percentage (%Fluo, Table⇓) of the total WBC number analysed. FACS analysis was confirmed by live-cell microscopy using the same probes. CHF patients had a significantly higher percentage of A-WBC or of V-WBC with evidence of cytosolic FR than CON (Table⇓). Only in CON was the percentage of A-WBC with evidence of cytosolic FR lower than the percentage of V-WBC with evidence of cytosolic FR (Table⇓). This indicates pulmonary clearance of WBC from FR to be effective in CON and to be deficient in CHF. CHF patients also had more WBC with loss of mitochondrial membrane potential (JC-1 probe) and with enhanced mitochondrial FR production (mito-ROS probe), both of which are indicative of mitochondrial dysfunction.
Conclusion: In CHF, more circulating WBC are loaded with FR. In CON, WBC are cleared from FR in the lungs but in CHF, this pulmonary clearance is deficient and FR accumulate in WBC. This accumulation induces mitochondrial dysfunction and mitochondrial production of FR in WBC. Because of absent pulmonary clearance from FR and because of mitochondrial production of FR, circulating WBC amplify oxidative stress in CHF.