Akademik Veri Yönetim Sistemi
FREE RADICAL BIOLOGY AND MEDICINE, cilt.171, ss.143-155, 2021 (SCI-Expanded)
Sickle cell anemia (SCA) is characterized by decreased red blood cell (RBC) deformability due to polymerization of deoxygenated hemoglobin, leading to abnormal mechanical properties of RBC, increased cellular adhesion, and microcirculatory obstruction. Prior work has demonstrated that NO center dot influences RBC hydration and deformability and is produced at a basal rate that increases under shear stress in normal RBC. Nevertheless, the origin and physiological relevance of nitric oxide (NO center dot) production and scavenging in RBC remains unclear. We aimed to assess the basal and shear-mediated production of NO center dot in RBC from SCA patients and control (CTRL) subjects. RBCs loaded with a fluorescent NO center dot detector, DAF-FM (4-Amino-5-methylamino- 2 ',7 '-difluorofluorescein diacetate), were imaged in microflow channels over 30-min without shear stress, followed by a 30min period under 0.5Pa shear stress. We utilized non-specific nitric oxide synthase (NOS) blockade and carbon monoxide (CO) saturation of hemoglobin to assess the contribution of NOS and hemoglobin, respectively, to NO center dot production. Quantification of DAF-FM fluorescence intensity in individual RBC showed an increase in NO center dot in SCA RBC at the start of the basal period; however, both SCA and CTRL RBC increased NO center dot by a similar quantity under shear. A subpopulation of sickle-shaped RBC exhibited lower basal NO center dot production compared to discoid RBC from SCA group, and under shear became more circular in the direction of shear when compared to discoid RBC from SCA and CTRL, which elongated. Both CO and NOS inhibition caused a decrease in basal NO center dot production. Shear-mediated NO center dot production was decreased by CO in all RBC, but was decreased by NOS blockade only in SCA. In conclusion, total NO center dot production is increased and shear-mediated NO center dot production is preserved in SCA RBC in a NOS-dependent manner. Sickle shaped RBC with inclusions have higher NO center dot production and they become more circular rather than elongated with shear.