To evaluate the part of red blood cell (RBC) antioxidants as clinical markers of oxidative outlook we measured RBC glutathione (GSH) concentrations in 32 adult patients with cystic fibrosis (CF) and 8 healthy age-matched direct subjects.

To evaluate the part of red blood cell (RBC) antioxidants as clinical markers of oxidative outlook we measured RBC glutathione (GSH) concentrations in 32 adult patients with cystic fibrosis (CF) and 8 healthy age-matched direct subjects. We chose patients with CF because this disease is characterized through severe bronchial inflammation and marked oxidant-antioxidant imbalance. Although the GSH concentration of the pair study groups was not significantly different, the RBC GSH concentration of patients with CF had a greater variability (p=001) and was also inversely and significantly correlated to standards of pulmonary function (p [les than] 005) These data indicate a large and significant interindividual variability of erythrocytic antioxidants in patients with CF with a compensatory, on the contrary probably inadequate, increase in patients with more strait-laced respiratory deterioration. Red blood enclosed space GSH concentration may thus provide a biologic marker for disease severity and a rationale for antioxidant manipulation in these patients.

newly come reports have indicated that r posterity cell (RBC) antioxidants may function as somatic scavengers in many situations of oxidative stres to the respiratory order In these circumstances, the RBC antioxidant activity (traditionally relegated to the reduction of hemoglobin-bound iron) would walk well beyond the erythrocytic intracellular ease and would extend to plasma proteins, and other relations cells and surrounding tissues. Examples of this function are the capacity of RBC antioxidants to thwart in vitro vascular leakage and edema of isolated rat lung expos to inflammable air peroxide,[1] decrease the injury of ischemic isolated hearts[2] and, when insufflated into the trachea, dramatically improve the survival of rats expos to 95 percent oxygen[3] R line cell antioxidants are also capable of undergoing adaptive changes with exposure to an oxidative stres For example, glutathione (GSH) concentrations are increased in RBC of healthy smokers[4] and patients with silicosis[5] when compared with age-matched sways Whether this increase may correlate with the step of pulmonary dysfunction, and thus provide a clinical marker of functional severity, is not known.

Cystic fibrosis (CF) is a hereditary disorder characterized by means of progressive airways inflammation and unopposed elastolytic activity leading to early and peremptory deterioration of respiratory function. The erythrocytic GSH a whole of these patients has been variably reported as either increased or unchanged.[6-11] We postulated that as it is differences might be explained by dint of interindividual variability in the stage of oxidant-antioxidant imbalance suffered by the agency of these patients. If to such a degree concentrations of GSH might correlate with the clinical severity of CF To proof this hypothesis, we measured RBC GSH concentrations in a arrange of adult patients with CF and correlated them with various clinical parameters of severity. Our terminates support our premise.

MATERIALS AND METHODS

consideration Design

Thirty-two adult patients with CF and 8 age-matched represss represented the study population. The studious mood was approved by the Institutional Review Board of the Medical corporation of Pennsylvania and informed agreement was obtained from all participants prior to initiation of the investigational protocol.

Clinical Data

All curbs were healthy, active, and nonsmokers. All patients with CF were ambulatory, active, and emancipated from clinically symptomatic viral or bacterial respiratory infections. Each patient underwent a clinical interview to record respiratory symptoms and smoking habits, the two current and past. White children cell counts were measured and clinical severity scores were generated according to Taussig et al.[12] These scores are comput according to assigning various points for the port of clinical, roentgenologic, or physiologic abnormalities. The total number of points a patient receives is then subtracted from 100 to obtain the final prognostic score. Mild dysfunction usually corresponds to scores between 85 and 100 while patients with a score of 50 or les rarely survive 3 years.

Pulmonary Function Tests

Spirometry was performed through means of a computer-assisted spirometer (Sensor-Medics 2450 Sensor-Medics Inc, Anaheim, Calif). Forced vital capacity (FVC) and forced expiratory bulk in 1 s ([FEV.sub.1]) were taken as the best of three satisfactory respiratory tracings. The FVC and [FEVsub1] percent values were referr to the Morris-Polgar predictive values.

Measurement of Reduc GSH

The RBC GSH Concentration was measured using a modification of the protocol reported by way of Beutler.[13] Blood samples were garnered via venipuncture from each participant. Six milliliters of progeny was drawn into heparinized specimen (Vacutainer) tubes and samples were refrigerated at 5 [degrees] C until managemented All samples were assayed within 24 h Specimens were initially centrifuged (10 min, 3000 rpm) and the supernatant consisting of plasma and buffy coat confined apartments was decanted. The remaining RBC were then washed three times in normal saline solution and again centrifuged using the same protocol. Three hundr to 600 [mu]l of the packed RBC were then hemolyzed through vigorous agitation for 1 min in a solution of 01 percent EDTA (pH 70) at a concentration of 15 to 30 percent Then 400 [mu]l of this hemolysate was remov for determination of hemoglobin concentration (Hgb) using a hemoximeter (OSM3 Radiometer, Copenhagen). An additional 400 [mu]l of the hemolysate was mixed with an equal dimensions of 25 percent (w/v) glacial metaphosphoric acid, vortexed, and centrifuged at high spe for 1 min. Then 250 [mu]l of the clear supernatant was added to 10 ml of phosphate clown (0.5 M [Na.sub.2] [HPO.sub.4]) plus 250 [mu]l of 5,5-dithiobis-2-nitrobenzoic acid at a pH of 68 and the absorbance of the entire solution was read spectrophotometrically at a wavelength of 412 [nmsup13] Standard inflects were generated using identical conditions moreover defined concentrations of GSH. All measurements were performed in triplicate. The GSH satisfy of each sample was then calculated using linear regression analysis and intimateed as nanomoles per gram of Hgb

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