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Effect of Oral Arginine Supplementation on Exhaled Nitric Oxide Concentration in Sickle Cell Anemia and Acute Chest Syndrome

Introduction Decreased exhaled nitric oxide levels (FENO) have been described in patients with sickle cell disease (SCD) and a history of acute chest syndrome (ACS) when compared with non-ACS controls. Oral arginine supplementation has been shown to increase FENO in healthy participants, but its effect in SCD patients is not known. Objective To determine the effect of oral arginine intake on FENO in sickle cell patients with and without history of ACS, and in healthy controls. Hypothesis No differences in the FENO increase were seen in SCD patients with a history of ACS (ACS+) compared with healthy controls (HC) and SCD patients without history of ACS (ACS−). Materials and Methods ACS+ (n=6), ACS− (n=9), and HC (n=7) patients were studied. At baseline, and after the administration of escalating doses of oral L-arginine (0.1, 0.2, and 0.4 g/kg), serial measurements were made of the following: FENO, plasma concentrations of arginine, ornithine, citrulline, aspartate, glutamate, arginine/ornithine ratio, nitrite, nitrate, heart rate (HR), respiratory rate (RR), blood pressure (BP), oxygen saturation (SpO2), forced expiratory volume in 1 second (FEV1), and forced vital capacity (FVC). Main Results At baseline, FENO did not differ among the groups. ACS− and ACS+ groups were deficient in arginine, and had decreased FEV1, FVC, and SaO2 when compared with HC patients. After arginine supplementation, FENO, arginine, ornithine, citrulline, nitrite, and the arginine/ornithine ratio increased similarly in all groups. Changes from baseline for HR, BP, SpO2, RR, FEV1, and FVC were minimal and similar in all groups. Conclusions In contrast to our earlier study, ACS+ patients had similar FENO values when compared with ACS− and HC patients. All SCD patients were arginine deficient at baseline and showed impairment in respiratory physiology when compared with HC patients. After arginine supplementation, FENO concentration increased in all groups to a similar degree, and lung function and physiologic parameters were minimally affected. The physiologic significance of alterations in FENO in SCD patients and its relationship to ACS predilection requires further delineation.