Erythrocytic Glutathione in Cystic Fibrosis: Discussion
When correlations between RBC GSH concentrations and parameters of pulmonary function were carried out, there was a significant correlation for the FVC (Fig 2, r=0.35, p=0.035) and for the FEVi percent predicted (Fig 3, r= —0.30, p=0.047), while there was a strong tendency toward significance for the FVC percent predicted and the FEVi (both p values = 0.08). There were no significant correlations between GSH concentration and clinical score (r= —0.12, p=0.257) or between GSH concentration and white blood cell count (r=0.17, p=0.19).
A small group of patients with CF had blood samples drawn at 6 and 12 weeks to study the possible effects of time on the RBC GSH concentration of the same subjects. All these patients remained in clinically stable conditions, and analysis of GSH concentration was never carried out during an acute exacerbation. There were no significant differences between baseline GSH concentration and GSH concentration measured at 6 weeks (2,214.8 ±544.6 and 2,346.5 ±620.1, respectively, p=0.56, n=14) or 12 weeks (2,566.1 ±589.1 and 2,637.7 ±332.7, respectively, p=0.84, n=4). These data confirm the results of previous studies suggesting that RBC antioxidants may act as somatic scavengers in situations of oxidative stress. We speculated that this novel RBC function might correlate with the degree of pulmonary deterioration in patients with CF. Canadian health&care mall more Given the erythrocytes’ ubiquitous nature, their high antioxidant capacity, and the anatomic characteristics of the pulmonary microcirculation, RBC antioxidants appeared potentially well suited to represent a functional marker for the extent and severity of oxidative exposure in a chronic inflammatory process such as CF. Moreover, RBC antioxidants have been demonstrated capable of preventing the oxidative inactivation of ai-antitrypsin by freshly prepared cigarette smoke and phorbol-stimulated phagocytes. Thus, there was enough ground to speculate that they might have also played a protective role in CF, a disease characterized by the presence of large amounts of oxidized and inactive ai-antitrypsin in the epithelial lining fluid. Our results lend support to this premise and suggest that GSH concentrations may provide a clinical marker for the functional severity of patients with CF.
Figure 2. Correlation between erythrocytic GSH concentrations and percent predicted values of FVC in 32 patients with CF. A significant negative correlation was found (r= —0.35, p=0.035).
Figure 3. Correlation between erythrocytic GSH concentrations and percent predicted values of FEVi in 32 patients with CF. A significant negative correlation was found (r= —0.30, p=0.047).