Inhaled nitric oxide augments nitric oxide transport on sickle cell hemoglobin without affecting oxygen affinity
Mark T. Gladwin, … , Griffin P. Rodgers, Frederick P. Ognibene
Mark T. Gladwin, … , Griffin P. Rodgers, Frederick P. Ognibene
Published October 1, 1999
Citation Information: J Clin Invest. 1999;104(7):937-945. https://doi.org/10.1172/JCI7637.
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Inhaled nitric oxide augments nitric oxide transport on sickle cell hemoglobin without affecting oxygen affinity

Abstract

Nitric oxide (NO) inhalation has been reported to increase the oxygen affinity of sickle cell erythrocytes. Also, proposed allosteric mechanisms for hemoglobin, based on S-nitrosation of β-chain cysteine 93, raise the possibilty of altering the pathophysiology of sickle cell disease by inhibiting polymerization or by increasing NO delivery to the tissue. We studied the effects of a 2-hour treatment, using varying concentrations of inhaled NO. Oxygen affinity, as measured by P50, did not respond to inhaled NO, either in controls or in individuals with sickle cell disease. At baseline, the arterial and venous levels of nitrosylated hemoglobin were not significantly different, but NO inhalation led to a dose-dependent increase in mean nitrosylated hemoglobin, and at the highest dosage, a significant arterial-venous difference emerged. The levels of nitrosylated hemoglobin are too low to affect overall hemoglobin oxygen affinity, but augmented NO transport to the microvasculature seems a promising strategy for improving microvascular perfusion.

Authors

Mark T. Gladwin, Alan N. Schechter, James H. Shelhamer, Lewis K. Pannell, Deirdre A. Conway, Borys W. Hrinczenko, James S. Nichols, Margaret E. Pease-Fye, Constance T. Noguchi, Griffin P. Rodgers, Frederick P. Ognibene

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HPLC-electrospray ionization mass spectrometry of SNO-hemoglobin digeste...
HPLC-electrospray ionization mass spectrometry of SNO-hemoglobin digested with endoproteinase Glu-C confirms specificity of S-nitrosocysteine reaction with hemoglobin β-chain cysteine 93. (a) Shown is the characteristic chromatogram, after enzymatic digestion of hemoglobin, of the 11–amino acid fragment (hemoglobin β-chain amino acids 91–101) that includes cysteine 93. The molecular weight is 1,305.5, with 3 predominant charge states (+4, +3, +2) with respective m/z of 327.4, 436.2, and 653.7 (inset). (b) Digestion of SNO-hemoglobin results in an increased retention time on the column and an increase in the molecular weight of the 11–amino acid fragment to 1,334.5, consistent with the addition of 29 mass units (NO has 30 mass units minus 1 mass unit of hydrogen lost during covalent binding). The m/z values of the 3 charge states (+4, +3, +2) increase to 334.6, 445.8, and 668.2, respectively (inset).