Redox imbalance, macrocytosis, and RBC homeostasis

Erythrocyte metabolism

Our aim is to present an updated overview of the erythrocyte metabolism highlighting its richness and complexity. We have manually collected and connected the available biochemical pathways and integrated them into a functional metabolic map. The focus of this map is on the main biochemical pathways consisting of glycolysis, the pentose phosphate pathway, redox metabolism, oxygen metabolism, purine/nucleoside metabolism, and membrane transport. Other recently emerging pathways are also curated, like the methionine salvage pathway, the glyoxalase system, carnitine metabolism, and the lands cycle, as well as remnants of the carboxylic acid metabolism. An additional goal of this review is to present the dynamics of erythrocyte metabolism, providing key numbers used to perform basic quantitative analyses. By synthesizing experimental and computational data, we conclude that glycolysis, pentose phosphate pathway, and redox metabolism are the foundations of erythrocyte metabolism. Additionally, the erythrocyte can sense oxygen levels and oxidative stress adjusting its mechanics, metabolism, and function. In conclusion, fine-tuning of erythrocyte metabolism controls one of the most important biological processes, that is, oxygen loading, transport, and delivery.

Can Red Blood Cell and Platelet Parameters Be Associated With Inflammation in Children With Tic Disorder?

OBJECTIVE

Tic disorder (TD) is one of the neurodevelopmental disorders and its etiology has not been fully elucidated. Complete blood count (CBC) values have been used as indicators of a systemic inflammatory response. In our study, we aimed to assess hemogram parameters in drug-naive, comorbidity-free children with TD compared with controls.

METHODS

This retrospective study included 62 drug-naive children with TD who had undergone CBC within one month prior to the study. A control group of 48 healthy children, matched for age and gender, without any organic or psychiatric disorders, was included. Statistical analysis was performed by using IBM SPSS Statistics for Windows, Version 22.0 (Released 2013; IBM Corp., Armonk, New York, United States).  Results: Hematocrit (p = 0.044), mean corpuscular volume (p = 0.002), platelet count (p = 0.011), and plateletcrit (p = 0.031) values were significantly higher in the TD group, whereas mean corpuscular hemoglobin concentration (p = 0.00) was significantly lower in the TD group. Additionally, a significant negative correlation was observed between the duration of illness and platelet (p = 0.05, r=-0.282), plateletcrit (p = 0.038, r = -0.295), and neutrophil count (p = 0.006, r = -0.391), while a positive correlation was found between the duration of illness and eosinophil count (p = 0.018, r = 0.336).

CONCLUSION

The results revealed several significant differences in hemogram parameters between TD patients and the control group. These may suggest the role of inflammation and/or other underlying mechanisms in TD and may inspire new studies. Future studies with larger and more homogeneous samples, including comprehensive inflammatory markers, may contribute to a deeper understanding of the relationship between inflammation and TD.

Genetic Modulation of the Erythrocyte Phenotype Associated with Retinopathy of Prematurity-A Multicenter Portuguese Cohort Study

The development of retinopathy of prematurity (ROP) may be influenced by anemia or a low fetal/adult hemoglobin ratio. We aimed to analyze the association between DNA methyltransferase 3 β (DNMT3B) (rs2424913), methylenetetrahydrofolate reductase (MTHFR) (rs1801133), and lysine-specific histone demethylase 1A (KDM1A) (rs7548692) polymorphisms, erythrocyte parameters during the first week of life, and ROP. In total, 396 infants (gestational age < 32 weeks or birth weight < 1500 g) were evaluated clinically and hematologically. Genotyping was performed using a MicroChip DNA on a platform employing iPlex MassARRAY^®. Multivariate regression was performed after determining risk factors for ROP using univariate regression. In the group of infants who developed ROP red blood cell distribution width (RDW), erythroblasts, and mean corpuscular volume (MCV) were higher, while mean hemoglobin and mean corpuscular hemoglobin concentration (MCHC) were lower; higher RDW was associated with KDM1A (AA), MTHFR (CC and CC + TT), KDM1A (AA) + MTHFR (CC), and KDM1A (AA) + DNMT3B (allele C); KDM1A (AA) + MTHFR (CC) were associated with higher RDW, erythroblasts, MCV, and mean corpuscular hemoglobin (MCH); higher MCV and MCH were also associated with KDM1A (AA) + MTHFR (CC) + DNMT3B (allele C). We concluded that the polymorphisms studied may influence susceptibility to ROP by modulating erythropoiesis and gene expression of the fetal/adult hemoglobin ratio.

The Impact of the COVID-19 Pandemic on Outcomes in Acute Pancreatitis: A Propensity Score Matched Study Comparing before and during the Pandemic

We aimed to evaluate the outcomes and survival of patients with acute pancreatitis who shared the same clinical form, age, and sex before the pandemic, during the pandemic, and among those with confirmed COVID-19 infection upon hospital admission. This consideration used the sparse data in the existing literature on the influence of the pandemic and COVID-19 infection on patients with acute pancreatitis. To accomplish this, we conducted a multicentric, retrospective case-control study using propensity score matching with a 2:1 match of 28 patients with SARS-CoV-2 infection and acute pancreatitis, with 56 patients with acute pancreatitis pre-pandemic, and 56 patients with acute pancreatitis during the pandemic. The study outcome demonstrated a six-fold relative risk of death in patients with acute pancreatitis and SARS-CoV-2 infection compared to those with acute pancreatitis before the pandemic. Furthermore, restrictive measures implemented during the pandemic period led to a partial delay in the care of patients with acute pancreatitis, which likely resulted in an impairment of their immune state. This, in certain circumstances, resulted in a restriction of surgical treatment indications, leading to a three-fold relative risk of death in patients with acute pancreatitis during the pandemic compared to those with acute pancreatitis before the pandemic.

Hypoxic storage of donor red cells preserves deformability after exposure to plasma from adults with sickle cell disease

BACKGROUND

Red cell (RBC) transfusions are beneficial for patients with sickle cell disease (SCD), but ex vivo studies suggest that inflamed plasma from patients with SCD during crises may damage these RBCs, diminishing their potential efficacy. The hypoxic storage of RBCs may improve transfusion efficacy by minimizing the storage lesion. We tested the hypotheses that (1) The donor RBCs exposed to the plasma of patients in crisis would have lower deformability and higher hemolysis than those exposed to non-crisis plasma, and (2) hypoxic storage, compared to standard storage, of donor RBCs could preserve deformability and reduce hemolysis.

STUDY DESIGN AND METHODS

18 SCD plasma samples from patients who had severe acute-phase symptoms (A-plasma; n = 9) or were at a steady-state (S = plasma; n = 9) were incubated with 16 RBC samples from eight units that were stored either under conventional(CRBC) or hypoxic(HRBC) conditions. Hemolysis and microcapillary deformability assays of these RBCs were analyzed using linear mixed-effect models after each sample was incubated in patient plasma overnight at 37°C RESULTS: Relative deformability was 0.036 higher (p < 0.0001) in HRBC pairs compared to CRBC pairs regardless of plasma type. Mean donor RBC hemolysis was 0.33% higher after incubation with A-plasma compared to S-plasma either with HRBC or CRBC (p = 0.04). HRBCs incubated with steady-state patient plasma demonstrated the highest deformability and lowest hemolysis.

CONCLUSION

Hypoxic storage significantly influenced RBC deformability. Patient condition significantly influenced post-incubation hemolysis. Together, HRBCs in steady-state plasma maximized donor red cell ex vivo function and survival.

Hemoglobin is an oxygen-dependent glutathione buffer adapting the intracellular reduced glutathione levels to oxygen availability

Fast changes in environmental oxygen availability translate into shifts in mitochondrial free radical production. An increase in intraerythrocytic reduced glutathione (GSH) during deoxygenation would support the detoxification of exogenous oxidants released into the circulation from hypoxic peripheral tissues. Although reported, the mechanism behind this acute oxygen-dependent regulation of GSH in red blood cells remains unknown. This study explores the role of hemoglobin (Hb) in the oxygen-dependent modulation of GSH levels in red blood cells. We have demonstrated that a decrease in Hb O₂ saturation to 50% or less observed in healthy humans while at high altitude, or in red blood cell suspensions results in rising of the intraerythrocytic GSH level that is proportional to the reduction in Hb O₂ saturation. This effect was not caused by the stimulation of GSH de novo synthesis or its release during deglutathionylation of Hb's cysteines. Using isothermal titration calorimetry and in silico modeling, we observed the non-covalent binding of four molecules of GSH to oxy-Hb and the release of two of them upon deoxygenation. Localization of the GSH binding sites within the Hb molecule was identified. Oxygen-dependent binding of GSH to oxy-Hb and its release upon deoxygenation occurred reciprocally to the binding and release of 2,3-bisphosphoglycerate. Furthermore, noncovalent binding of GSH to Hb moderately increased Hb oxygen affinity. Taken together, our findings have identified an adaptive mechanism by which red blood cells may provide an advanced antioxidant defense to respond to oxidative challenges immediately upon deoxygenation.

Relationship between mean corpuscular volume and 30-day mortality in patients with intracerebral hemorrhage: Evidence from the MIMIC-III database

Previous studies have shown that mean corpuscular volume (MCV) levels are associated with the prognosis of patients with cardiovascular disease. However, the relationship between MCV levels and mortality in patients with intracerebral hemorrhage (ICH) remains unclear. Patients with ICH were extracted from the Medical Information Mart for Intensive Care-III database. The primary outcome measure was 30-day mortality. Multivariate Cox regression analysis was used to investigate the relationship between MCV at admission and 30-day mortality in ICH patients. We enrolled 1100 patients with ICH. After adjustment for potential confounders, we found that a 1 unit increase in MCV (fl) was associated with a 3% increase in 30-day mortality (HR = 1.03, 95% CI = 1.01-1.05, P = .0015). High MCV (MCV ≥ 92 fl) compared with the low MCV group (MCV < 87 fl) showed a 46% increase of 30-day mortality (HR = 1.46, 95% CI = 1.10-1.92 P = .008). In subgroups analysis's the results remained stable. We demonstrated that MCV at admission was positively associated with 30-day mortality. The Kaplan-Meier (KM) method was used to plot survival curves of three groups with different admission MCV levels.

Relationship between Red Blood Cell Indices (MCV, MCH, and MCHC) and Major Adverse Cardiovascular Events in Anemic and Nonanemic Patients with Acute Coronary Syndrome

BACKGROUND

Previous studies have shown that increased mean corpuscular volume (MCV) is an independent predictor for worse outcomes in coronary artery disease. However, as parameters to classify different types of anemia together with MCV, the relationship between mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and long-term outcomes in acute coronary syndrome (ACS) remains obscure. Moreover, few studies have compared the prognostic value of these red blood cell indices in anemic and nonanemic patients with ACS.

METHODS AND RESULTS

In this single-center observational cohort study, we enrolled 393 patients diagnosed with ACS, including 75 anemic and 318 nonanemic patients. The composite end points were defined as major adverse cardiovascular events (MACEs). After a median follow-up of 31.24 months, Kaplan-Meier survival analysis showed that higher MCV and MCH but not MCHC were significantly associated with increased MACEs in nonanemic ACS patients. Among the enrolled ACS patients without anemia, Cox regression analysis revealed that high MCV and MCH were correlated with increased MACEs after adjustment for cardiovascular risk factors, and receiver operating characteristic (ROC) curve analysis further confirmed the predictive value of high MCV and MCH. In bivariate correlation and linear regression analysis, plasma homocysteine was positively correlated with MCV and MCH but not MCHC in the nonanemic group even after adjusting for age, male sex, BMI, SBP, DBP, smoking, and diabetes. However, MCV, MCH, and MCHC showed no predictive value for MACEs, and no correlation was found between these red blood cell indices and homocysteine in ACS patients with anemia.

CONCLUSION

After adjusting for cardiovascular risk factors, this study showed that higher admission MCV and MCH but not MCHC were independent predictors for long-term MACEs and positively correlated with homocysteine levels in the blood among the nonanemic but not anemic patients with ACS in China.

Berberine Recovered Oxidative Stress Induced by Sodium Nitrite in Rat Erythrocytes

OBJECTIVE

Berberine, a plant derived alkaloid, present in Berberis species is well known as one of the most important antioxidants. The current research aimed to study the heamatoprotective characteristics of berberine and clarify its plausible mechanisms against sodium nitrite.

METHODS

Forty numbers of male Sprague Dawley rats were categorized into five equal groups, including group 1: control (normal saline); group 2: berberine (100 mg/kg); group 3: sodium nitrite (80 mg/kg); group 4: sodium nitrite (80 mg/kg) plus berberine (50 mg/kg) and group 5: sodium nitrite (80 mg/kg) plus berberine (100 mg/kg) groups. All animals were orally administrated for two months once daily. At the end of the 60th day, blood samples were withdrawn by cardiac puncture and collected in test vials when the animals had been anesthetized with ketamine (70 mg/kg). Then, hemolysate was prepared and the oxidative stress biomarkers, lipid peroxidation, and antioxidant capacity of erythrocytes were evaluated.

RESULTS

Feeding of rats with sodium nitrite remarkably enhanced malondialdehyde (MDA) (p=0.001) levels and considerably reduced the levels of glutathione (GSH) (p=0.001), and also reduced the enzymatic activities of glutathione peroxidase (GPx) (p=0.02), superoxide dismutase (SOD) (p=0.001), glutathione reductase (GR) (p=0.02), and catalase (CAT) (p=0.01). However, the co-administration of these animals with 100 mg/kg of berberine remarkably reverted the values to reach nearly a normal level. While 50 mg/kg berberine failed to restore significantly all of these antioxidant biomarkers at a normal level.

CONCLUSION

Our results clearly demonstrated that berberine in a dose-dependent manner led to protection against sodium nitrite-induced oxidative injury in rat erythrocytes, which possibly reflects the antioxidant ability of this alkaloid.

Redox Balance in β-Thalassemia and Sickle Cell Disease: A Love and Hate Relationship

β-thalassemia and sickle cell disease (SCD) are inherited hemoglobinopathies that result in both quantitative and qualitative variations in the β-globin chain. These in turn lead to instability in the generated hemoglobin (Hb) or to a globin chain imbalance that affects the oxidative environment both intracellularly and extracellularly. While oxidative stress is not among the primary etiologies of β-thalassemia and SCD, it plays a significant role in the pathogenesis of these diseases. Different mechanisms exist behind the development of oxidative stress; the result of which is cytotoxicity, causing the oxidation of cellular components that can eventually lead to cell death and organ damage. In this review, we summarize the mechanisms of oxidative stress development in β-thalassemia and SCD and describe the current and potential antioxidant therapeutic strategies. Finally, we discuss the role of targeted therapy in achieving an optimal redox balance.

Myostatin Knockout Limits Exercise-Induced Reduction in Bovine Erythrocyte Oxidative Stress by Enhancing the Efficiency of the Pentose Phosphate Pathway

Moderate exercise can strengthen the body, however, exhaustive exercise generates large amounts of reactive oxygen species (ROS). Although erythrocytes have antioxidant systems that quickly eliminate ROS, erythrocytes become overwhelmed by ROS when the body is under oxidative stress, such as during exhaustive exercise. Myostatin (MSTN) has important effects on muscle hair development. Individuals lacking myostatin (MSTN) exhibit increased muscle mass. The purpose of this study was to investigate the mechanism by which MSTN affects erythrocyte antioxidant changes after exhaustive exercise in cattle. Antioxidant and metabolite detection analysis, western blotting, immunofluorescence, and fatty acid methyl ester analysis were used to assess exercise-associated antioxidant changes in erythrocytes with or without MSTN. Knockdown of MSTN enhances Glucose-6-phosphate dehydrogenase (G6PD) activity after exhaustive exercise. MSTN and its receptors were present on the erythrocyte membrane, but their levels, especially that of TGF-β RI, were significantly reduced in the absence of MSTN and following exhaustive exercise. Our results suggest that knockout of MSTN accelerates the pentose phosphate pathway (PPP), thereby enhancing the antioxidant capacity of erythrocytes. These results provide important insights into the role of MSTN in erythrocyte antioxidant regulation after exhaustive exercise.

Fisetin, a potential caloric restriction mimetic, modulates ionic homeostasis in senescence induced and naturally aged rats

CONTEXT

Fisetin as a caloric restriction mimetic (CRM) exerts numerous beneficial effects on different aging model systems. The effect of fisetin on erythrocyte membrane functions against induced aging is not very clear.

OBJECTIVES

The potential role of fisetin in the modulation of erythrocytes membrane-bound transporters during natural and induced aging in rats was assessed.

MATERIALS AND METHODS

Male Wistar rats were used for natural and D-galactose (D-gal) induced aging model. After supplementation with fisetin, the activities of different membrane transporters and biomarkers of oxidative stress were evaluated.

RESULTS

Fisetin modulated membrane transporters such as calcium-ATPase, sodium potassium-ATPase and sodium hydrogen exchanger during senescence-induced as well as in natural aging. Fisetin also protected oxidative modifications in rat aging.

DISCUSSION AND CONCLUSION

Fisetin supplementation improves the ionic homeostasis, a factor that is involved in the aetiology of several age-associated diseases, in naturally old as well as D-gal induced aged rats.

The Role of RBC Oxidative Stress in Sickle Cell Disease: From the Molecular Basis to Pathologic Implications

Sickle cell disease (SCD) is an inherited monogenic disorder and the most common severe hemoglobinopathy in the world. SCD is characterized by a point mutation in the β-globin gene, which results in hemoglobin (Hb) S production, leading to a variety of mechanistic and phenotypic changes within the sickle red blood cell (RBC). In SCD, the sickle RBCs are the root cause of the disease and they are a primary source of oxidative stress since sickle RBC redox state is compromised due to an imbalance between prooxidants and antioxidants. This imbalance in redox state is a result of a continuous production of reactive oxygen species (ROS) within the sickle RBC caused by the constant endogenous Hb autoxidation and NADPH oxidase activation, as well as by a deficiency in the antioxidant defense system. Accumulation of non-neutralized ROS within the sickle RBCs affects RBC membrane structure and function, leading to membrane integrity deficiency, low deformability, phosphatidylserine exposure, and release of micro-vesicles. These oxidative stress-associated RBC phenotypic modifications consequently evoke a myriad of physiological changes involved in multi-system manifestations. Thus, RBC oxidative stress in SCD can ultimately instigate major processes involved in organ damage. The critical role of the sickle RBC ROS production and its regulation in SCD pathophysiology are discussed here.

Biochemical Evaluation of the Effects of Hydroxyurea in Vitro on Red Blood Cells

Hydroxyurea (HU) is a low-cost, low-toxicity drug that is often used in diseases, such as sickle cell anemia and different types of cancer. Its effects on the red blood cells (RBC) are still not fully understood. The in vitro effects of HU were evaluated on the biochemical parameters of the RBC from healthy individuals that were treated with 0.6 mM or 0.8 mM HU for 30 min and 1 h. After 30 min, there was a significant increase in almost all of the parameters analyzed in the two concentrations of HU, except for the pyruvate kinase (PK) activity. A treatment with 0.8 mM HU for 1 h resulted in a reduction of the levels of lipid peroxidation, Fe³⁺, and in the activities of some of the enzymes, such as glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PD), and PK. After the incubation for 1 h, the levels of H₂O₂, lipid peroxidation, reduced glutathione (GSH), enzymatic activity (hexokinase, G6PD, and superoxide dismutase (SOD) were reduced with the treatment of 0.8 mM HU when compared with 0.6 mM. The results have suggested that a treatment with HU at a concentration of 0.8 mM seemed to be more efficient in protecting against the free radicals, as well as in treating diseases, such as sickle cell anemia. HU appears to preferentially stimulate the pentose pathway over the glycolytic pathway. Although this study was carried out with the RBC from healthy individuals, the changes described in this study may help to elucidate the mechanisms of action of HU when administered for therapeutic purposes.

Nonlinear Relationship Between Macrocytic Anemia and Decompensated Hepatitis B Virus Associated Cirrhosis: A Population-Based Cross-Sectional Study

Background: Mean corpuscular volume (MCV) is major used as an indicator for the differential diagnosis of anemia. Macrocytic anemia in decompensated cirrhosis is common. However, the relationship between macrocytic anemia and decompensated hepatitis B virus (HBV) associated cirrhosis has not been fully addressed.

Methods: In this cross-sectional study, a total of 457 patients diagnosed decompensated HBV associated cirrhosis who met all inclusion criteria from 2011 to 2018 were analyzed. Association between macrocytic anemia and the liver damaged (Model for End Stage Liver Disease (MELD) score) were examined using multiple logistic regression analyses and identified using smooth curve fitting.

Results: Compared with normocytic anemia, MCV and MELD are significantly positively correlated in macrocytic anemia (p < 0.001). A non-linear relationship of MCV and MELD association was found though the piecewise linear spline models in patients with decompensated HBV associated cirrhosis. MCV positive correlated with MELD when the MCV was greater than 98.2 fl (regression coefficient = 0.008, 95% CI 0.1, 0.4).

Conclusion: Macrocytic anemia may be a reliable predictor for mortality because it is closely related to the degree of liver damage in patients with decompensated HBV associated cirrhosis.

Red Blood Cell Indices in Relation to Post-stroke Psychiatric Disorders: A Longitudinal Study in a Follow-up Stroke Clinic

BACKGROUND

Depression and anxiety after stroke are common conditions that are likely to be neglected. Abnormal red blood cell (RBC) indices may be associated with neuropsychiatric disorders. However, the association of RBC indices with post-stroke depression (PSD) and poststroke anxiety (PSA) has not been sufficiently investigated.

METHODS

We aimed to investigate the trajectory of post-stroke depression and anxiety in our follow- up stroke clinic at 1, 3, and 6 months, and the association of RBC indices with these. One hundred and sixty-two patients with a new diagnosis of ischemic stroke were followed up at 1, 3, and 6 months, and underwent Patient Health Questionnaire-9 (PHQ-9) and the general anxiety disorder 7-item (GAD-7) questionnaire for evaluation of depression and anxiety, respectively. First, we used Kaplan-Meier analysis to investigate the accumulated incidences of post-stroke depression and post-stroke anxiety. Next, to explore the association of RBC indices with psychiatric disorders after an ischemic stroke attack, we adjusted for demographic and vascular risk factors using multivariate Cox regression analysis.

RESULTS

Of the 162 patients with new-onset of ischemic stroke, we found the accumulated incidence rates of PSD (1.2%, 17.9%, and 35.8%) and PSA (1.2%, 13.6%, and 15.4%) at 1, 3, and 6 months, respectively. The incident PSD and PSA increased 3 months after a stroke attack. Multivariate Cox regression analysis indicated independent positive associations between PSD risk and higher mean corpuscular volume (MCV) (OR=1.42, 95% CI=1.16-1.76), older age (OR=2.63, 95% CI=1.16-5.93), and a negative relationship between male sex (OR=0.95, 95% CI=0.91-0.99) and PSA.

CONCLUSION

The risks of PSD and PSA increased substantially 3 months beyond stroke onset. Of the RBC indices, higher MCV, showed an independent positive association with PSD.

Metformin protects red blood cells against rotenone induced oxidative stress and cytotoxicity

CONTEXT

The anti-diabetic medicine metformin has been reported as an anti-ageing drug candidate as it mimics the benefits of caloric restriction and reduces ageing-related oxidative stress in various experimental organisms.

OBJECTIVE

We investigated the possible anti-oxidative role of metformin against rotenone-induced oxidative stress and cytotoxicity in erythrocytes of Wistar rats. Rotenone is a well-known inducer of oxidative stress which leads to a cellular redox imbalance.

MATERIALS AND METHODS

We have co-exposed the experimental rats with rotenone (2.5 mg/kg, i.p.) and metformin (300 mg/kg, orally) for 30 days to investigate the protective effects of metformin on various rotenone-induced impaired oxidative stress biomarkers in rat erythrocytes.

RESULTS

We found that a significant alleviation in the levels of rotenone-induced pro-oxidant and anti-oxidant markers following exposure of metformin.

DISCUSSION AND CONCLUSIONS

Our findings suggest that metformin supplementation shows a protective role in against rotenone-induced redox imbalance and cytotoxicity in rat erythrocytes.

Red Blood Cells and Hemoglobin in Human Atherosclerosis and Related Arterial Diseases

As the main particulate component of the circulating blood, RBCs play major roles in physiological hemodynamics and impact all arterial wall pathologies. RBCs are the main determinant of blood viscosity, defining the frictional forces exerted by the blood on the arterial wall. This function is used in phylogeny and ontogeny of the cardiovascular (CV) system, allowing the acquisition of vasomotricity adapted to local metabolic demands, and systemic arterial pressure after birth. In pathology, RBCs collide with the arterial wall, inducing both local retention of their membranous lipids and local hemolysis, releasing heme-Fe⁺⁺ with a high toxicity for arterial cells: endothelial and smooth muscle cells (SMCs) cardiomyocytes, neurons, etc. Specifically, overloading of cells by Fe⁺⁺ promotes cell death. This local hemolysis is an event associated with early and advanced stages of human atherosclerosis. Similarly, the permanent renewal of mural RBC clotting is the major support of oxidation in abdominal aortic aneurysm. In parallel, calcifications promote intramural hemorrhages, and hemorrhages promote an osteoblastic phenotypic shift of arterial wall cells. Different plasma or tissue systems are able, at least in part, to limit this injury by acting at the different levels of this system.

Mean Corpuscular Volume Predicts Adverse Outcomes Following Peripheral Angioplasty With Stenting and Is Associated With On-Treatment Platelet Reactivity

Structural aspects of red blood cells have been associated with cardiovascular disease. No data linking mean corpuscular volume (MCV) to clinical outcomes and on-treatment platelet reactivity in patients with peripheral artery disease (PAD) are available. We investigated a composite of atherothrombotic events and target vessel restenosis or reocclusion following infrainguinal stenting for stable PAD. Residual platelet reactivity was measured by light transmission aggregometry (LTA) and the VerifyNow assays. We included 104 patients receiving dual antiplatelet therapy (DAPT) with aspirin and clopidogrel. In receiver-operating characteristic analysis, MCV effectively discriminated between patients with and without adverse outcomes and identified a MCV ≤90.8 fL as optimal cutoff. Adverse outcomes occurred significantly more often in patients with low MCV (log-rank P = .002). In univariable Cox regression analysis, low MCV was associated with an increased risk of future adverse outcomes (hazard ratio [HR]: 2.662 [95%CI: 1.304-5.434]; P = .007) and remained significantly associated after adjustment (HR: 2.591 [95%CI: 1.242-5.403]; P = .011). Mean corpuscular volume was inversely correlated with arachidonic acid (AA)- and adenosine diphosphate (ADP)-inducible platelet reactivity by LTA and with the VerifyNow aspirin assay. Low MCV is associated with adverse outcomes over 2 years following infrainguinal stenting. Mean corpuscular volume correlates inversely with AA- and ADP-inducible platelet reactivity during DAPT.

Oxidative status of maternal blood in pregnancies burdened by inherited thrombophilias

Oxidative status of maternal blood represents an important parameter of pregnancy that is involved in both, regulation of physiological processes and (if significantly altered) development of different pregnancy complications. Inherited thrombophilias represent genetic disorders that increase the risk of thromboembolism in pregnancy. Little is known about the impact of thrombophilia on the oxidative status of maternal blood. In this study, we analyzed oxidative status of blood of 56 women with pregnancies burdened by inherited thrombophilias. The status was established at three different trimesters using biochemical assays and electrochemical measurements, and it was compared to 10 age- and trimester-matching controls. Activities of superoxide dismutase, catalase, and glutathione reductase in the 1st and the 2nd trimester of thrombophilic pregnancy were lower than controls. Also, there was less oxidation in the plasma, according to higher concentration of reduced thiols and lower oxidation-reduction potential. Therefore, it appears that thrombophilic mothers do not experience oxidative stress in the circulation in the first two trimesters. However, the rise in GPx, GR and SOD activities in the 3rd trimester of thrombophilic pregnancy implies that the risk of oxidative stress is increased during the late pregnancy. These results are important for developing antioxidative treatment that could tackle thrombophilia-related pregnancy complications.

Oxidative Stress and Thrombosis during Aging: The Roles of Oxidative Stress in RBCs in Venous Thrombosis

Mid-life stage adults are at higher risk of developing venous thrombosis (VT)/thromboembolism (VT/E). Aging is characterized by an overproduction of reactive oxygen species (ROS), which could evoke a series of physiological changes involved in thrombosis. Here, we focus on the critical role of ROS within the red blood cell (RBC) in initiating venous thrombosis during aging. Growing evidence has shifted our interest in the role of unjustifiably unvalued RBCs in blood coagulation. RBCs can be a major source of oxidative stress during aging, since RBC redox homeostasis is generally compromised due to the discrepancy between prooxidants and antioxidants. As a result, ROS accumulate within the RBC due to the constant endogenous hemoglobin (Hb) autoxidation and NADPH oxidase activation, and the uptake of extracellular ROS released by other cells in the circulation. The elevated RBC ROS level affects the RBC membrane structure and function, causing loss of membrane integrity, and decreased deformability. These changes impair RBC function in hemostasis and thrombosis, favoring a hypercoagulable state through enhanced RBC aggregation, RBC binding to endothelial cells affecting nitric oxide availability, RBC-induced platelet activation consequently modulating their activity, RBC interaction with and activation of coagulation factors, increased RBC phosphatidylserine exposure and release of microvesicles, accelerated aging and hemolysis. Thus, RBC oxidative stress during aging typifies an ultimate mechanism in system failure, which can affect major processes involved in the development of venous thrombosis in a variety of ways. The reevaluated concept of the critical role of RBC ROS in the activation of thrombotic events during aging will help identify potential targets for novel strategies to prevent/reduce the risk for VT/E or VT/E recurrences in mid-life stage adults.

Prognostic Factors for Cognitive Recovery Beyond Early Poststroke Cognitive Impairment (PSCI): A Prospective Cohort Study of Spontaneous Intracerebral Hemorrhage

Background: Poststroke cognitive impairment (PSCI) has been increasingly recognized in patients, but some stroke survivors appear to show cognitive improvement beyond the acute stage. The risk factors associated with cognitive recovery after spontaneous intracerebral hemorrhage (ICH) onset have not yet been sufficiently investigated in prospective studies.

Objective: We aimed to identify the trajectory of post-ICH cognitive impairment and the association of potential prognostic factors with follow-up cognitive recovery beyond early PSCI.

Methods: In this stroke center-based cohort study, 141 consecutive dementia-free patients with spontaneous ICH were included and underwent Montreal Cognitive Assessment (MoCA) evaluation for cognitive function at baseline (within 2 weeks of ICH onset) and the shortened MoCA (short-MoCA) at a 6-month follow-up. To explore the prognostic factors associated with trajectory of cognition after an ICH onset, we adjusted for demographic and vascular risk factors, using multivariate logistic regression analysis.

Results: Of the 141 ICH patients, approximately three quarters (106/141) were diagnosed with early PSCI (MoCA score <26) within 2 weeks of ICH onset. The multiple logistic regression indicated independent positive associations between risk of early PSCI and dominant-hemisphere hemorrhage [odd's ratio (OR): 8.845 (3.347–23.371); P < 0.001], mean corpuscular volume (MCV) [OR: 1.079 (1.002–1.162); P = 0.043], admission systolic blood pressure (sBP) [OR: 1.021 (1.005–1.038); P = 0.012]. Furthermore, 36% (33/90) of ICH survivors who had early PSCI exhibited cognitive recovery at the 6-month follow-up. After examining potential predictors through multiple linear regression based on stepwise, there were independent negative associations between cognitive recovery and dominant hemisphere hemorrhage [OR: 6.955 (1.604–30.162); P < 0.01], lobar ICH [OR: 8.363 (1.479–47.290); P = 0.016], years of education ≤ 9 [OR: 5.145 (1.254–21.105); P = 0.023], and MCV [OR: 1.660 (1.171–2.354); P = 0.004]. Baseline cognitive performance in the domains of visuospatial/executive function, attention, orientation, and language showed positive correlations with cognitive improvement (P < 0.05).

Conclusion: In this cohort study of dementia-free survivors of ICH, our results show that one in three early PSCI survivors exhibit cognitive recovery, in relation to dominant-hemisphere hematoma, lobar ICH, educational history, and MCV levels. Future clinical trials including ICH survivors with cognitive dysfunction should assess these factors.

Blood cell markers that can predict the long-term outcomes of patients with colorectal cancer

Objectives

To identify blood cell markers that predict the long-term outcomes of patients with colorectal cancer.

Methods

Data from 892 stage II and III colorectal cancer patients who underwent R0 resection were included. We analyzed the correlations of the preoperative blood data, previously reported prognostic indices, and clinicopathologic factors with the long-term outcomes, such as relapse-free survival and overall survival, using univariate and multivariate analyses.

Results

Multivariate analysis showed that tumor location, stage, mean corpuscular volume, neutrophil-to-lymphocyte ratio, and lymphocyte-to- monocyte ratio were significantly correlated with relapse-free survival. A mean corpuscular volume ≥80.5 fL, neutrophil-to-lymphocyte ratio ≥5.5, and lymphocyte-to- monocyte ratio <3.4 had hazard ratios for disease relapse between 1.39 and 1.93. The cumulative scores of these three factors were aggregated into a laboratory prognostic score, with a maximum score at 6. The relapse-free survival and overall survival were well stratified by a laboratory prognostic score between 0–3 and 4–6, respectively, independent of the stage.

Conclusion

The mean corpuscular volume, neutrophil-to-lymphocyte ratio, and lymphocyte-to- monocyte ratio can serve as blood cell markers to predict the long-term outcomes of patients who underwent R0 resection for stage II/III colorectal cancer.

Reduced deformability contributes to impaired deoxygenation-induced ATP release from red blood cells of older adult humans

KEY POINTS

Red blood cells (RBCs) release ATP in response to deoxygenation, which can increase blood flow to help match oxygen supply with tissue metabolic demand. This release of ATP is impaired in RBCs from older adults, but the underlying mechanisms are unknown. In this study, improving RBC deformability in older adults restored deoxygenation-induced ATP release, whereas decreasing RBC deformability in young adults reduced ATP release to the level of that of older adults. In contrast, treating RBCs with a phosphodiesterase 3 inhibitor did not affect ATP release in either age group, possibly due to intact intracellular signalling downstream of deoxygenation as indicated by preserved cAMP and ATP release responses to pharmacological G_i protein activation in RBCs from older adults. These findings are the first to demonstrate that the age-related decrease in RBC deformability is a primary mechanism of impaired deoxygenation-induced ATP release, which may have implications for treating impaired vascular control with advancing age.

ABSTRACT

In response to haemoglobin deoxygenation, red blood cells (RBCs) release ATP, which binds to endothelial purinergic receptors and stimulates vasodilatation. This ATP release is impaired in RBCs from older vs. young adults, but the underlying mechanisms are unknown. Using isolated RBCs from young (24 ± 1 years) and older (65 ± 2 years) adults, we tested the hypothesis that age-related changes in RBC deformability (Study 1) and cAMP signalling (Study 2) contribute to the impairment. RBC ATP release during normoxia ( P O 2 ∼112 mmHg) and hypoxia ( P O 2 ∼20 mmHg) was quantified with the luciferin-luciferase technique following RBC incubation with Y-27632 (Rho-kinase inhibitor to increase deformability), diamide (cell-stiffening agent), cilostazol (phosphodiesterase 3 inhibitor), or vehicle control. The mean change in RBC ATP release from normoxia to hypoxia in control conditions was significantly impaired in older vs. young (∼50% vs. ∼120%; P < 0.05). RBC deformability was also lower in older vs. young as indicated by a higher RBC transit time (RCTT) measured by blood filtrometry (RCTT: 8.541 ± 0.050 vs. 8.234 ± 0.098 a.u., respectively; P < 0.05). Y-27632 improved RBC deformability (RCTT: 8.228 ± 0.083) and ATP release (111.7 ± 17.2%) in older and diamide decreased RBC deformability (RCTT: 8.955 ± 0.114) and ATP release (67.4 ± 11.8%) in young (P < 0.05), abolishing the age group differences (P > 0.05). Cilostazol did not change ATP release in either age group (P > 0.05), and RBC cAMP and ATP release to pharmacological G_i protein activation was similar in both groups (P > 0.05). We conclude that decreased RBC deformability is a primary contributor to age-related impairments in RBC ATP release, which may have implications for impaired vascular control with advancing age.

Low dose exposure of patulin and protective effect of epicatechin on blood cells in vitro

In the present study, we aimed to assess antioxidant status in erythrocytes in vitro after patulin (PAT) and epicatechin exposure by measuring antioxidant enzymes (superoxide-dismutase - SOD, glutathione peroxidase - GPx and catalase - CAT) and parameters associated with oxidative stress (malondialdehyde - MDA and ROS). We also investigated the effect of PAT on viability and count of lymphocytes and lymphocyte subpopulations in rabbit blood in vitro. Whole blood of rabbits was used for analysis of antioxidant changes in rabbit erythrocytes after epicatechin and PAT treatment (separately or in combination, at concentrations of 0.2; 2; 20; 200 µg mL^-1 of epicatechin and 0.5; 5; 10 µg mL^-1 of PAT). Whole blood of rabbits was also used for analysis of count and viability of lymphocytes after PAT treatment at concentrations of 10; 25 and 50 µg mL^-1. Results from our experiment confirmed the ability of epicatechin to protect cells against oxidative stress and lipoperoxidation. Our findings indicate that mycotoxin PAT in low concentrations did not affect the activity of antioxidant enzymes in erythrocytes of rabbits significantly. Only slight non-significant changes in lymphocytes count after treatment with low doses of PAT in rabbit blood were observed.

Prolonged erythrocyte auto-incubation as an alternative model for oxidant generation system

This study investigated the effects of incubation period and melatonin treatment on red blood cell (RBC) metabolism in an auto-incubation model of H₂O₂-induced oxidative stress. The study was carried out on three healthy adult donors by incubating RBCs in their own plasma at 37 °C, or under the influence of 1 mM H₂O₂ with and without 100 μM melatonin at different times (0, 1, 3 and 6 h). We assessed incubation period, treatment, as well as any interaction effects between these predictors on erythrocyte osmoregulation, hemolytic rate, oxidative stress markers, and adenylate nucleotide levels. We did not find any relevant effects of both incubation period and treatments on osmotic, antioxidant and adenylate parameters. On the other hand, hemolysis degree and biomolecule oxidation levels in the plasma increased over time, 3-fold and about 25%, respectively, regardless any treatment influence. H₂O₂ treatment more than doubled protein carbonyl groups, regardless time in plasma, and in a time-depending way in erythrocyte membrane extract, effects that were neutralized by melatonin treatment. Through multivariate analyses, we could expand the understanding of energy and redox metabolisms in the maintenance of cellular integrity and metabolic homeostasis. Another interesting observation was the 65-75% contribution of the oxidative lesion markers on hemolysis. Hence, these findings suggested a new and more intuitive RBC suspension model and reinforced the beneficial use of melatonin in human disorders.

Mean Corpuscular Volume and Mortality in Incident Hemodialysis Patients

BACKGROUND/AIMS

Anemia is common in patients with advanced chronic kidney disease (CKD). A proportion of patients present with macrocytic anemia, manifested by elevated mean corpuscular volume (MCV), which has been associated with worse outcomes in CKD patients. However, it is unknown whether elevated MCV is associated with higher mortality risk in incident hemodialysis (HD) patients.

METHODS

This retrospective observational cohort study examined all-cause, cardiovascular, and infectious mortality associations with both baseline and time-varying MCV in 109,501 incident HD patients using Cox proportional hazards models with 3 levels of hierarchical multivariable adjustment. Odds ratios of high versus low baseline MCV were evaluated using logistic regression.

RESULTS

The mean age of patients was 65 ± 15 (standard deviation) years and the cohort was 44% female, 58% diabetic, and 31% African American. Higher MCV was associated with older age, female sex, non-Hispanic White race-ethnicity, alcohol consumption, and having a decreased albumin or protein intake. Patients with higher MCV levels (> 98 fL) had a higher all-cause, cardiovascular, and infectious mortality risk in both baseline and time varying models, and across all levels of adjustment. In the fully adjusted models, compared to a reference of MCV 92-< 94 fL, patients with a baseline MCV > 100+ fL had a 28% higher risk of all-cause mortality (hazard ratio [HR] 1.28, 95% CI 1.22-1.34), 27% higher risk of cardiovascular mortality (HR 1.27, 95% CI 1.18-1.36), and 18% higher risk of infectious mortality (HR 1.18, 95% CI 1.02-1.38). Associations of higher MCV with these adverse outcomes persisted across all examined subgroups of clinical characteristics.

CONCLUSIONS

Higher MCV was associated with higher all-cause, cardiovascular, and infectious mortality in HD patients. Further investigation is necessary to understand the underlying nature of the observed association.

A prospective cohort examination of haematological parameters in relation to cancer death and incidence: the Busselton Health Study

BACKGROUND

Cancer risk is associated with serum iron levels. The aim of this study was to evaluate whether haematological parameters reflect serum iron levels and may also be associated with cancer risk.

METHODS

We studied 1564 men and 1769 women who were enrolled in the Busselton Health Study, Western Australia. Haematological parameters evaluated included haemoglobin (Hb), mean cell volume (MCV), mean cell haemoglobin (MCH) and mean cell haemoglobin concentration (MCHC) and red cell distribution width (RCDW). Statistical analyses included t-tests for quantitative variables, chi-square tests for categorical variables and Cox proportional hazards regression modelling for cancer incidence and death.

RESULTS

There was marginal evidence of an association between MCV (as a continuous variable) and non-skin cancer incidence in women (HR 1.15, 95% CI 1.013, 1.302; p = 0.030) but the hazard ratio was attenuated to non-significance after adjustment for serum ferritin (SF), iron and transferrin saturation (TS) (HR 1.11, 95% CI 0.972, 1.264; p = 0.126). There was strong evidence of an association between MCHC and prostate cancer incidence in men; the estimated hazard ratio for an increase of one SD (0.5) in MCHC was 1.27 (95% CI 1.064, 1.507; p = 0.008). These results remained significant after further adjustment for SF and iron; the estimated hazard ratio for an increase of one SD (0.5) in MCHC was 1.25 (p = 0.014, 95% CI 1.05 to 1.48).

CONCLUSIONS

The MCHC and MCV were associated with cancer incidence in a Western Australian population, although only MCHC remained associated with prostate cancer after adjusting with serum iron and TS (circulating iron) and SF (storage iron). Haematological parameters are thus of limited utility in population profiling for future cancer risk.

The prognostic value of interaction between mean corpuscular volume and red cell distribution width in mortality in chronic kidney disease

Recently, both red cell distribution width (RDW) and mean corpuscular volume (MCV) have been associated with unfavorable outcomes in several medical conditions. Therefore, we conducted this retrospective study of 1075 patients with stage 3-5 chronic kidney disease to investigate whether interactions between RDW and MCV influence the risk of mortality. These patients were divided into four groups: group A (n = 415), RDW ≤ 14.9% and MCV ≤ 91.6 fL; group B (n = 232), RDW > 14.9% and MCV ≤ 91.6 fL; group C (n = 307), RDW ≤ 14.9% and MCV > 91.6 fL; and group D (n = 121), RDW > 14.9% and MCV > 91.6 fL. The adjusted hazard ratio (HR) of all-cause mortality for group B versus group A was 1.44 (95% confidence interval [CI], 1.14-2.12, p = 0.02), group C versus group A 2.14 (95% CI, 1.31-3.48, p = 0.002), and group D versus group A 5.06 (95% CI, 3.06-8.37, p < 0.001). There was a multiplicative interaction between MCV and RDW in predicting patient mortality. The use of RDW in conjunction with MCV may improve healthcare by identifying those at an increased risk for mortality compared with the use of either RDW or MCV alone.

Evaluation of lipid peroxidation and the level of some elements in rat erythrocytes during separate and combined vanadium and magnesium administration

The impact of vanadium (V) and magnesium (Mg) as sodium metavanadate (SMV, 0.125 mg V/ml) and magnesium sulfate (MS, 0.06 mg Mg/ml) on lipid peroxidation (LPO) and selected elements in the rat erythrocytes (RBCs) was investigated. Relationships between some indices determined in RBC were also studied. SMV alone (Group II) elevated the malondialdehyde level (MDA_RBC) (by 95% and 60%), compared with the control (Group I) and MS-supplemented rats (Group III), respectively, reduced the concentration of Cu_RBC (by 23.5%), in comparison with Group I, but did not change the levels of Na_RBC, K_RBC, and Ca_RBC, whereas MS alone (Group III) only reduced the Cu_RBC concentration (by 22%), compared with Group I. The SMV + MS combination (Group IV) reduced and elevated the Cu_RBC (by 24%) and Ca_RBC (by 111%) concentrations, respectively, in comparison with Groups I and III, and these changes were induced by the V-Mg antagonistic and synergistic interaction, respectively. The combined SMV + MS effect also enhanced the MDA_RBC level, compared with Groups I (by 79%) and III (by 47%) and slightly limited its concentration, compared with Group II, which, in turn, resulted from the distinct trend toward the V-Mg antagonistic interaction. We can conclude that V (as SMV) is able to stimulate LPO in rat RBCs and that V-Mg interactive effects are involved in changes in Cu_RBC, Ca_RBC, and MDA_RBC. Further studies are needed to elucidate the exact mechanisms of the V-Mg antagonistic/synergistic interactions and to provide insight into the biochemical mechanisms of changes in rats suffering from anemia [1], characterized by a disrupted antioxidant barrier in RBCs [2] and an intensified free radical process in these cells.

Rapamycin mitigates erythrocyte membrane transport functions and oxidative stress during aging in rats

Erythrocyte membrane is a suitable model to study various metabolic and physiological functions as it undergoes variety of biochemical changes during aging. An age-dependent modulatory effect of rapamycin on erythrocyte membrane functions is completely unknown. Therefore, the present study was undertaken to investigate the effect of rapamycin on age-dependent impaired activities of transporters/exchangers, altered levels of redox biomarkers, viz. protein carbonyl (PC), lipid hydroperoxides (LHs), total thiol (-SH), sialic acid (SA) and intracellular calcium ion [Ca²⁺]i, and osmotic fragility of erythrocyte membrane. A significant reduction in membrane-bound activities of Na⁺/K⁺-ATPase (NKA) and Ca²⁺-ATPase (PMCA), and levels of -SH and SA was observed along with a simultaneous induction in Na⁺/H⁺ exchanger (NHE) activity and levels of [Ca²⁺]i, PC, LH and osmotic fragility in old-aged rats. Rapamycin was found to be a promising age-delaying drug that significantly reversed the aging-induced impaired activities of membrane-bound ATPases and altered levels of redox biomarkers.

Enhancing uniformity and overall quality of red cell concentrate with anaerobic storage

BACKGROUND

Recent research focused on understanding stored red blood cell (RBC) quality has demonstrated high variability in measures of RBC function and health across units. Studies have historically linked this high variability to variations in processing, storage method, and age. More recently, a large number of studies have focused on differences in donor demographics, donor iron sufficiency, and genetic predisposition of the donor to poor storage, particularly through mechanisms of accelerated oxidative damage. A study was undertaken to evaluate a potential additional source of unit to unit variation in stored RBC: the role of variable percent oxygen saturation (%SO₂) levels on blood quality parameters during storage.

MATERIALS AND METHODS

%SO₂ data from 492 LR-RBC/AS-3 units used for internal and external collaborative research was included in the analysis. Whole blood units were processed into red blood cells, AS-3 added, leucocyte reduced, in compliance with American Association of Blood Banks guidelines. LR-RBC/AS-3 products were subsequently analysed for %SO₂ levels within 3-24 hours of phlebotomy using a co-oximeter. Separately, to evaluate the impact of pre-storage as well as increasing levels of %SO₂ during storage, a pool-and-split study was performed. Four units of LR-RBC/AS-3 were split 6 ways; "as is" (control), hyperoxygenated to more than 90%, and four levels of pre-storage %SO₂. The units were periodically sampled up to 42 days and analysed for %SO₂, pCO₂, methaemoglobin, ATP, 2,3-BPG as well as with the metabolomics workflow.

RESULTS

The measured mean %SO₂ in LR-RBC/AS-3 within 24 hours of collection was 45.9±17.5% with (32.7-61.0 IQR). %SO₂ in all products increased to approximately 95-100% in three weeks. Measured blood quality parameters including ATP, % haemolysis, methaemoglobin, oxidised lipids, and GSH/GSSG indicated suppressed cellular metabolism and increased red cell degradation in response to higher %SO₂ levels.

DISCUSSION

The surprisingly high variability in starting %SO₂ levels, coupled with negative impacts of high oxygen saturation on red blood cell quality indicates that oxygen levels may be an important and under-appreciated source of unit-to-unit variability in RBC quality.

Mean corpuscular volume levels and all-cause and liver cancer mortality

BACKGROUND

An elevated mean corpuscular volume (MCV) is associated with aging, nutrition, alcohol abuse and more, and it is known as a survival predictor in chronically ill patients. The aim of this study was to investigate the association between MCV levels and mortality from all-causes, cancer and site-specific cancer in a non-anemic healthy population.

METHODS

A total of 36,260 participants aged 40 years or older who underwent routine check-ups at Seoul National University Hospital Health Promotion Center between 1995 and 2008 were followed-up for mortality until December 31, 2008, retrospectively.

RESULTS

During an average follow-up of 8.0 years, 1107 deaths including 547 cancer deaths were observed. The adjusted hazard ratios (aHRs) of the subjects with the highest quartile of MCV ≥95.8 fL in men and MCV ≥94.2 fL in women for all-cause and cancer mortality were 1.44 [95% confidence interval (CI), 1.15-1.80] and 1.51 (95% CI, 1.10-2.07) for men and 1.55 (95% CI, 1.08-2.22) and 1.25 (95% CI, 0.74-2.11) for women, respectively, compared with those in the reference group (90.5 fL≤MC <93.0 fL in men and 89.2 fL≤MCV<91.6 fL in women). Elevated MCV level was related to an increased risk of liver cancer mortality in men (aHR, 3.55; 95% CI, 1.75-7.21).

CONCLUSIONS

This study suggests that the elevated MCV level in non-anemic cancer-free individuals was associated with increased all-cause mortality in both men and women, and with cancer mortality, in particular liver cancer mortality in men. Future prospective studies are required to consolidate our findings.

Mean Corpuscular Volume and Mortality in Patients with CKD

BACKGROUND AND OBJECTIVES

Mean corpuscular volume is the measure of the average size of the circulatory erythrocyte, and it is principally used as an index for the differential diagnosis of anemia. Recently, mean corpuscular volume has been associated with mortality in many clinical settings. However, the association of mean corpuscular volume with mortality in patients with CKD has not been fully addressed.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective observational cohort study of 1439 patients with stages 3-5 CKD and baseline mean corpuscular volume values from 2004 to 2012 in a medical center. The study cohort was divided into the high-mean corpuscular volume group and the low-mean corpuscular volume group by the median value (90.8 fl) of mean corpuscular volume. The baseline patient information included demographic data, laboratory parameters, medications, and comorbid conditions. The independent association of mean corpuscular volume with mortality was examined using multivariate Cox regression analysis.

RESULTS

Of the 1439 participants, 234 patients (16.2%) died during a median follow-up of 1.9 years (interquartile range, 1.1-3.8 years). The crude overall mortality rate was significantly higher in the high-mean corpuscular volume group (high-mean corpuscular volume group, 22.7%; low-mean corpuscular volume group, 9.7%; P<0.001). In the fully adjusted models, the high-mean corpuscular volume group was associated with higher risks of all-cause mortality (hazard ratio, 2.19; 95% confidence interval, 1.62 to 2.96; P<0.001), cardiovascular mortality (hazard ratio, 3.57; 95% confidence interval, 1.80 to 7.06; P<0.001), and infection-related mortality (hazard ratio, 2.22; 95% confidence interval, 1.41 to 3.49; P=0.001) compared with the low-mean corpuscular volume group.

CONCLUSIONS

In patients with stages 3-5 CKD, mean corpuscular volume was associated with all-cause mortality, cardiovascular disease mortality, and infection-associated mortality, independent of other factors. The underlying pathophysiologic mechanisms warrant additional investigation.

Origin, Function, and Fate of Metallothionein in Human Blood

Toxic heavy metals, toxic organic compounds, reactive oxygen species (ROS), infections, and temperature are well-known metallothionein (MT) inducers in human blood. The current review aims to summarize synthesis, function, and fate of human blood MT in response to the known MT inducers. Part of the MTs that are synthesized in different organs such as the liver, kidney, and spleen is transported and stored in different blood cells and in plasma. Cells of the circulatory system also synthesize MT. From the circulation, MT returns to the kidney where the metal-bound MTs are degraded to release the metal ion that in turn induces MT expression therein. The blood MTs play important roles in metal detoxification, transportation, and storage. By neutralizing ROS, MTs protect blood cells from oxidative stress-induced cytotoxicity and genotoxicity. Arguably, MTs are also involved in immune suppression. Given the permeating distribution of blood MT throughout the body as well as its diverse role in the protection against harmful environmental factors and in metal homeostasis, MT could be better recognized as a major public health protein.

Multiplicative interaction between mean corpuscular volume and red cell distribution width with target organ damage in hypertensive patients

BACKGROUND

Accumulating evidence suggests that increased red cell distribution width (RDW) and mean corpuscular volume (MCV) were both poor prognostic factors for patients with cardiovascular diseases. Recently, the multiplicative interaction between RDW and MCV has been observed for predicting mortality in elderly patients without anemia; however, the relationship between the product of RDW-MCV and hypertension-induced target organ damage (TOD) has not been evaluated.

METHODS

We performed a cross-sectional study in 1115 hypertensive patients. RDW and MCV were determined using automated hematology analyzers. Prevalence of TOD was evaluated by estimated glomerular filtration rate, carotid intima-media thickness, and left ventricular mass index.

RESULTS

The prevalence of TOD was observed to be increased with the RDW or product of RDW-MCV quartiles. Moreover, RDW, MCV and product of RDW-MCV were significantly higher in patients with TOD compared to those without TOD. According to two logistic regression models, the associations of RDW and MCV with TOD were lost after adjustment for other factors. However, product of RDW-MCV remains an independent predictor of TOD, with per 0.4 fL increase in the product of RDW-MCV associated with a 16% increased risk of TOD (P=.012).

CONCLUSIONS

The inclusion of MCV by calculating the product of RDW-MCV appears to enhance the association of RDW with TOD.

Antioxidant enzymes as redox-based biomarkers: a brief review

The field of redox proteomics focuses to a large extent on analyzing cysteine oxidation in proteins under different experimental conditions and states of diseases. The identification and localization of oxidized cysteines within the cellular milieu is critical for understanding the redox regulation of proteins under physiological and pathophysiological conditions, and it will in turn provide important information that are potentially useful for the development of novel strategies in the treatment and prevention of diseases associated with oxidative stress. Antioxidant enzymes that catalyze oxidation/reduction processes are able to serve as redox biomarkers in various human diseases, and they are key regulators controlling the redox state of functional proteins. Redox regulators with antioxidant properties related to active mediators, cellular organelles, and the surrounding environments are all connected within a network and are involved in diseases related to redox imbalance including cancer, ischemia/reperfusion injury, neurodegenerative diseases, as well as normal aging. In this review, we will briefly look at the selected aspects of oxidative thiol modification in antioxidant enzymes and thiol oxidation in proteins affected by redox control of antioxidant enzymes and their relation to disease. [BMB Reports 2015; 48(4): 200-208]

Anemia and Red Blood Cell Indices Predict HIV-Associated Neurocognitive Impairment in the Highly Active Antiretroviral Therapy Era

BACKGROUND

Anemia has been linked to adverse human immunodeficiency virus (HIV) outcomes, including dementia, in the era before highly active antiretroviral therapy (HAART). Milder forms of HIV-associated neurocognitive disorder (HAND) remain common in HIV-infected persons, despite HAART, but whether anemia predicts HAND in the HAART era is unknown.

METHODS

We evaluated time-dependent associations of anemia and cross-sectional associations of red blood cell indices with neurocognitive impairment in a multicenter, HAART-era HIV cohort study (N = 1261), adjusting for potential confounders, including age, nadir CD4(+) T-cell count, zidovudine use, and comorbid conditions. Subjects underwent comprehensive neuropsychiatric and neuromedical assessments.

RESULTS

HAND, defined according to standardized criteria, occurred in 595 subjects (47%) at entry. Mean corpuscular volume and mean corpuscular hemoglobin were positively associated with the global deficit score, a continuous measure of neurocognitive impairment (both P < .01), as well as with all HAND, milder forms of HAND, and HIV-associated dementia in multivariable analyses (all P < .05). Anemia independently predicted development of HAND during a median follow-up of 72 months (adjusted hazard ratio, 1.55; P < .01).

CONCLUSIONS

Anemia and red blood cell indices predict HAND in the HAART era and may contribute to risk assessment. Future studies should address whether treating anemia may help to prevent HAND or improve cognitive function in HIV-infected persons.

A thermolabile aldolase A mutant causes fever-induced recurrent rhabdomyolysis without hemolytic anemia

Aldolase A deficiency has been reported as a rare cause of hemolytic anemia occasionally associated with myopathy. We identified a deleterious homozygous mutation in the ALDOA gene in 3 siblings with episodic rhabdomyolysis without hemolytic anemia. Myoglobinuria was always triggered by febrile illnesses. We show that the underlying mechanism involves an exacerbation of aldolase A deficiency at high temperatures that affected myoblasts but not erythrocytes. The aldolase A deficiency was rescued by arginine supplementation in vitro but not by glycerol, betaine or benzylhydantoin, three other known chaperones, suggesting that arginine-mediated rescue operated by a mechanism other than protein chaperoning. Lipid droplets accumulated in patient myoblasts relative to control and this was increased by cytokines, and reduced by dexamethasone. Our results expand the clinical spectrum of aldolase A deficiency to isolated temperature-dependent rhabdomyolysis, and suggest that thermolability may be tissue specific. We also propose a treatment for this severe disease.

Impact on red blood cell immunity patterns in postoperative phase following total hip arthroplasty

Objective

In this study, we aimed to measure changes in red blood cell (RBC) immunity and cytokine levels after performing total hip replacement surgery.

Material and methods

Twenty patients receiving total hip arthroplasty were investigated by measuring presurgical and postoperative RBC natural tumor erythrocyte rosette rate (NTERR), RBC C3b receptor rosette rate (RC3bRR), RBC membrane CD35, CD58 and CD59 expression and cytokine levels [including tumor necrosis factor α (TNF-α), interleukin 2 (IL-2), interferon γ (IFN-γ), interleukin 10 (IL-10) and prostaglandin E₂ (PGE₂)]. Blood samples were collected on the day before surgery and on the first day after hip arthroplasty.

Results

Postoperative NTERR and RC3bRR were significantly lower than presurgical levels (p < 0.05). The RBC membrane CD35, CD58 and CD59 expressions were significantly decreased in the postoperative phase compared to pre-operative levels. Importantly, RBC promoting lymphocyte proliferation rates were significantly reduced after surgery. In addition, postoperative TNF-α, IL-2 and IFN-γ levels in RBC and lymphocyte culture fluid were lower than those pre-operation, whereas IL-10 and PGE₂ were significantly increased compared to presurgical levels (p < 0.05).

Conclusions

The modification of RBC immune function may be involved in the occurrence and development of the infection following hip arthroplasty, and this suggests a novel strategy to prevent such infection.

Inborn defects in the antioxidant systems of human red blood cells

Red blood cells (RBCs) contain large amounts of iron and operate in highly oxygenated tissues. As a result, these cells encounter a continuous oxidative stress. Protective mechanisms against oxidation include prevention of formation of reactive oxygen species (ROS), scavenging of various forms of ROS, and repair of oxidized cellular contents. In general, a partial defect in any of these systems can harm RBCs and promote senescence, but is without chronic hemolytic complaints. In this review we summarize the often rare inborn defects that interfere with the various protective mechanisms present in RBCs. NADPH is the main source of reduction equivalents in RBCs, used by most of the protective systems. When NADPH becomes limiting, red cells are prone to being damaged. In many of the severe RBC enzyme deficiencies, a lack of protective enzyme activity is frustrating erythropoiesis or is not restricted to RBCs. Common hereditary RBC disorders, such as thalassemia, sickle-cell trait, and unstable hemoglobins, give rise to increased oxidative stress caused by free heme and iron generated from hemoglobin. The beneficial effect of thalassemia minor, sickle-cell trait, and glucose-6-phosphate dehydrogenase deficiency on survival of malaria infection may well be due to the shared feature of enhanced oxidative stress. This may inhibit parasite growth, enhance uptake of infected RBCs by spleen macrophages, and/or cause less cytoadherence of the infected cells to capillary endothelium.

Senescence in cell oxidative status in two bird species with contrasting life expectancy

Oxidative stress occurs when the production of reactive oxygen species (ROS) by an organism exceeds its capacity to mitigate the damaging effects of the ROS. Consequently, oxidative stress hypotheses of ageing argue that a decline in fecundity and an increase in the likelihood of death with advancing age reported at the organism level are driven by gradual disruption of the oxidative balance at the cellular level. Here, we measured erythrocyte resistance to oxidative stress in the same individuals over several years in two free-living bird species with contrasting life expectancy, the great tit (known maximum life expectancy is 15.4 years) and the Alpine swift (26 years). In both species, we found evidence for senescence in cell resistance to oxidative stress, with patterns of senescence becoming apparent as subjects get older. In the Alpine swift, there was also evidence for positive selection on cell resistance to oxidative stress, the more resistant subjects being longer lived. The present findings of inter-individual selection and intra-individual deterioration in cell oxidative status at old age in free-living animals support a role for oxidative stress in the ageing of wild animals.