Increase in Red Blood Cell-Nitric Oxide Synthase Dependent Nitric Oxide Production during Red Blood Cell Aging in Health and Disease: A Study on Age Dependent Changes of Rheologic and Enzymatic Properties in Red Blood Cells

Abstract

AimTo investigate RBC-NOS dependent NO signaling during in vivo RBC aging in health and disease.MethodRBC from fifteen healthy volunteers (HC) and four patients with type 2 diabetes mellitus (DM) were separated in seven subpopulations by Percoll density gradient centrifugation.ResultsThe proportion of old RBC was significantly higher in DM compared to HC. In both groups, in vivo aging was marked by changes in RBC shape and decreased cell volume. RBC nitrite, as marker for NO, was higher in DM and increased in both HC and DM during aging. RBC deformability was lower in DM and significantly decreased in old compared to young RBC in both HC and DM. RBC-NOS Serine1177 phosphorylation, indicating enzyme activation, increased during aging in both HC and DM. Arginase I activity remained unchanged during aging in HC. In DM, arginase I activity was significantly higher in young RBC compared to HC but decreased during aging. In HC, concentration of L-arginine, the substrate of RBC-NOS and arginase I, significantly dropped from young to old RBC. In DM, L-arginine concentration was significantly higher in young RBC compared to HC and significantly decreased during aging. In blood from healthy subjects, RBC-NOS activation was additionally inhibited by N5-(1-iminoethyl)-L-Ornithine dihydrochloride which decreased RBC nitrite, and impaired RBC deformability of all but the oldest RBC subpopulation.ConclusionThis study first-time showed highest RBC-NOS activation and NO production in old RBC, possibly to counteract the negative impact of cell shrinkage on RBC deformability. This was even more pronounced in DM. It is further suggested that highly produced NO only insufficiently affects cell function of old RBC maybe because of isolated RBC-NOS in old RBC thus decreasing NO bioavailability. Thus, increasing NO availability may improve RBC function and may extend cell life span in old RBC.

Nitric oxide synthetic pathway and cGMP levels are altered in red blood cells from end-stage renal disease patients

“…As mentioned above, in our study, we found that basal RBC-NOS was significantly more activated in uremic erythrocytes than in controls. There are indeed studies indicating that, under several pathological conditions, certain mechanisms that compensate deficient NO production may be activated [25,28,45]. In particular, these mechanisms include plasma oxidative stress, a condition existing in uremia [46,47], which can cause a paradoxical increase in RBC-NOS activity [48].…”

“…Thus, the RBC pool may be a potentially compensatory intravascular compartment for endothelial dysfunction in diabetes [27]. More recently Bizjak et al [28], by a study on age-dependent changes of rheology and enzymatic properties in RBCs, showed highest RBC-NOS activation and NO production in old RBC, suggesting that this is probably required to counteract the negative impact of cell shrinkage on RBC deformability. In addition, they found this effect even more pronounced in diabetic patients.…”

Modulation of Lung Function by Increased Nitric Oxide Production

“…Among them, garlic has shown the highest NOS stimulating activity [ Table/Fig -2]. In this experimental design, the subjects of Group B were then supplemented with approximately 4 gm (2 cloves) of raw garlic per day for three months, garlic dose recommended in the study by Tattelman E [16] and the University of Maryland Medical Center [17], referred as experimental group II (Group C). At the end of three months of garlic supplementation the subjects of Group C were again subjected to pulmonary function tests.…”

Recent insights into nitrite signaling processes in blood

“…First, nitrite is formed from the oxidation of nitric oxide (NO) produced by nitric oxide synthase, found in the RBC itself and in endothelial cells (Kleinbongard et al , 2003; Kleinbongard et al , 2006; Cortese-Krott et al , 2012; Grau et al , 2013; Wood et al , 2013; Bizjak et al , 2015). The auto-oxidation of NO to nitrite proceeds slowly ( k = 2×10 6 M −2 s −1 ) compared to oxidation of nitric oxide to nitrate by hemoglobin ( k = 8×10 7 M −1 s −1 ) (Shiva, 2012).…”