Abstract:A decreased nitric oxide (NO) bioavailability and an increased oxidative stress play a pivotal role in different cardiovascular pathologies. As red blood cells (RBCs) participate in NO formation in the bloodstream, the aim of this study was to outline the metabolic profile of L-arginine (Arg)/NO pathway and of oxidative stress status in RBCs and in plasma of patients with microvascular angina (MVA), investigating similarities and differences with respect to coronary artery disease (CAD) patients or healthy con… Show more
“…Currently, there is little direct evidence for such a mechanism to be involved in coronary MVA. However, an impairment of red blood cell (RBC) capacity to produce NO has been reported 51 in patients with MVA, possibly reflecting an impaired RBC metabolic signalling. Figure 5Possible effects of compromised metabolic signalling in vascular adaptation.…”
Coronary microvascular networks play the key role in determining blood flow distribution in the heart. Matching local blood supply to tissue metabolic demand entails continuous adaptation of coronary vessels via regulation of smooth muscle tone and structural dilated vessel diameter. The importance of coronary microcirculation for relevant pathological conditions including angina in patients with normal or near-normal coronary angiograms [microvascular angina (MVA)] and heart failure with preserved ejection fraction (HFpEF) is increasingly recognized. For MVA, clinical studies have shown a prevalence of up to 40% in patients with suspected coronary artery disease and a relevant impact on adverse cardiovascular events including cardiac death, stroke, and heart failure. Despite a continuously increasing number of corresponding clinical studies, the knowledge on pathophysiological cause–effect relations involving coronary microcirculation is, however, still very limited. A number of pathophysiological hypotheses for MVA and HFpEF have been suggested but are not established to a degree, which would allow definition of nosological entities, stratification of affected patients, or development of effective therapeutic strategies. This may be related to a steep decline in experimental (animal) pathophysiological studies in this area during the last 15 years. Since technology to experimentally investigate microvascular pathophysiology in the beating heart is increasingly, in principle, available, a concerted effort to build ‘coronary microcirculatory observatories’ to close this gap and to accelerate clinical progress in this area is suggested.
“…Currently, there is little direct evidence for such a mechanism to be involved in coronary MVA. However, an impairment of red blood cell (RBC) capacity to produce NO has been reported 51 in patients with MVA, possibly reflecting an impaired RBC metabolic signalling. Figure 5Possible effects of compromised metabolic signalling in vascular adaptation.…”
Coronary microvascular networks play the key role in determining blood flow distribution in the heart. Matching local blood supply to tissue metabolic demand entails continuous adaptation of coronary vessels via regulation of smooth muscle tone and structural dilated vessel diameter. The importance of coronary microcirculation for relevant pathological conditions including angina in patients with normal or near-normal coronary angiograms [microvascular angina (MVA)] and heart failure with preserved ejection fraction (HFpEF) is increasingly recognized. For MVA, clinical studies have shown a prevalence of up to 40% in patients with suspected coronary artery disease and a relevant impact on adverse cardiovascular events including cardiac death, stroke, and heart failure. Despite a continuously increasing number of corresponding clinical studies, the knowledge on pathophysiological cause–effect relations involving coronary microcirculation is, however, still very limited. A number of pathophysiological hypotheses for MVA and HFpEF have been suggested but are not established to a degree, which would allow definition of nosological entities, stratification of affected patients, or development of effective therapeutic strategies. This may be related to a steep decline in experimental (animal) pathophysiological studies in this area during the last 15 years. Since technology to experimentally investigate microvascular pathophysiology in the beating heart is increasingly, in principle, available, a concerted effort to build ‘coronary microcirculatory observatories’ to close this gap and to accelerate clinical progress in this area is suggested.
“…Notably, RBC-NOS expression and activity are decreased in RBCs from patients with endothelial dysfunction and coronary artery disease [6,22,23]. However, along with the study just mentioned, there are only a few studies concerning NO production, RBC-NOS expression, and activation in RBCs from other pathological conditions [23][24][25].…”
Section: Introductionmentioning
confidence: 99%
“…However, along with the study just mentioned, there are only a few studies concerning NO production, RBC-NOS expression, and activation in RBCs from other pathological conditions [23][24][25]. Some of them show an increased RBC-NOS activation in RBCs from sickle cell anemia patients and a significant increase in cGMP levels within RBCs has also been found as compared to healthy subjects [25,26].…”
Red blood cells (RBCs) enzymatically produce nitric oxide (NO) by a functional RBC-nitric oxide synthase (RBC-NOS). NO is a vascular key regulatory molecule. In RBCs its generation is complex and influenced by several factors, including insulin, acetylcholine, and calcium. NO availability is reduced in end-stage renal disease (ESRD) and associated with endothelial dysfunction. We previously demonstrated that, through increased phosphatidylserine membrane exposure, ESRD-RBCs augmented their adhesion to human cultured endothelium, in which NO bioavailability decreased. Since RBC-NOS-dependent NO production in ESRD is unknown, this study aimed to investigate RBC-NOS levels/activation, NO production/bioavailability in RBCs from healthy control subjects (C, N = 18) and ESRD patients (N = 27). Although RBC-NOS expression was lower in ESRDRBCs, NO, cyclic guanosine monophosphate (cGMP), RBC-NOS Serine1177 phosphorylation level and eNOS/ Calmodulin (CaM)/Heat Shock Protein-90 (HSP90) interaction levels were higher in ESRD-RBCs, indicating increased enzyme activation. Conversely, following RBCs stimulation with insulin or ionomycin, NO and cGMP levels were significantly lower in ESRD-than in C-RBCs, suggesting that uremia might reduce the RBC-NOS response to further stimuli. Additionally, the activity of multidrug-resistance-associated protein-4 (MRP4; cGMPmembrane transporter) was significantly lower in ESRDRBCs, suggesting a possible compromised efflux of cGMP across the ESRD-RBCs membrane. This study for the first time showed highest basal RBC-NOS activation in ESRDRBCs, possibly to reduce the negative impact of decreased NOS expression. It is further conceivable that high NO production only partially affects cell function of ESRDRBCs maybe because in vivo they are unable to respond to physiologic stimuli, such as calcium and/or insulin.Keywords End-stage renal disease Á Red blood cells Á Nitric oxide Á cGMP Á Nitric oxide synthase Mario Bonomini, and Assunta Pandolfi have contributed equally to the study.Electronic supplementary material The online version of this article
“…Adiponectin coordinates monocyte-macrophage activation in endothelial cells, conversion of macrophages to foam cells, as well as proliferation and migration of smooth muscle cells, and thereby prevents the initiation and progression of atherosclerosis [26]. Oxidative stress or systemic inflammation may impair endothelial-dependent vasodilation and coronary microvascular flow reserve by reducing NO activity [27]. Adiponectin has been shown to cause vasodilation and increase in blood flow by induction of NO release with several different pathways [28].…”
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
