Effect of glucose-6-phosphate dehydrogenase deficiency on some biophysical properties of human erythrocytes

Mechanisms underlying the anti-aging activity of bergamot (Citrus bergamia) extract in human red blood cells

Introduction: Aging is a process characterised by a decline in physiological functions. Reactive species play a crucial role in the aging rate. Due to the close relationship between aging and oxidative stress, functional foods rich in phytochemicals are excellent candidates to neutralise age-related changes. Aim: This investigation aims to verify the potential protective role of bergamot (Citrus bergamia, Femminello cultivar) peel and juice extract in a model of aging represented by human red blood cells (RBCs) exposed to D-Galactose (DGal). Methods: Bergamot peel and juice extracts were subjected to RP-HPLC/PDA/MS for determination of their composition in bioactive compounds. Markers of oxidative stress, including ROS production, thiobarbituric acid reactive substances (TBARS) levels -a marker of lipid peroxidation, oxidation of total protein sulfhydryl groups, as well as the expression and anion exchange capability of band 3 and glycated haemoglobin (A1c) production have been investigated in RBCs treated with D-Gal for 24 h, with or without pre-incubation for 15 min with 5 μg/mL peel or juice extract. In addition, the activity of the endogenous antioxidant system, including catalase (CAT) and superoxide dismutase (SOD), as well as the diversion of the RBC metabolism from glycolysis towards the pentose phosphate pathway shunt, as denoted by activation of glucose-6-phosphate dehydrogenase (G6PDH), have been explored. Results: Data shown here suggest that bergamot peel and juice extract i) prevented the D-Gal-induced ROS production, and consequently, oxidative stress injury to biological macromolecules including membrane lipids and proteins; ii) significantly restored D-Gal-induced alterations in the distribution and ion transport kinetics of band 3; iii) blunted A1c production; iv) effectively impeded the over-activation of the endogenous antioxidant enzymes CAT and SOD; and v) significantly prevented the activation of G6PDH. Discussion: These results further contribute to shed light on aging mechanisms in human RBCs and identify bergamot as a functional food rich in natural antioxidants useful for prevention and treatment of oxidative stress-related changes, which may lead to pathological states during aging.

Effects of lead exposure on blood electrical impedance spectroscopy of mice

Background

Lead is a nonessential heavy metal, which can inhibit heme synthesis and has significant cytotoxic effects. Nevertheless, its effect on the electrical properties of red blood cells (RBCs) remains unclear. Consequently, this study aimed to investigate the electrical properties and the electrophysiological mechanism of lead exposure in mouse blood using Electrical Impedance Spectroscopy (EIS) in 0.01–100 MHz frequency range. Data characteristic of the impedance spectrum, Bodes plot, Nyquist plot and Nichols plot, and Constant Phase Element (CPE) equivalent circuit model were used to explicitly analyze the differences in amplitude–frequency, phase–frequency, and the frequency characteristics of blood in electrical impedance properties.

Results

Compared with the healthy blood in control mice, the changes in blood exposed to lead were as follows: (i) the hematocrit decreased; (ii) the amplitude–frequency and phase–frequency characteristics of electrical impedance decreased; (iii) the characteristic frequencies (f₀) were significantly increased; (iv) the electrical impedance of plasma, erythrocyte membrane, and hemoglobin decreased, while the conductivity increased. (v) The pseudo-capacitance of cell membrane (CPE_Tm) and the intracellular pseudo-capacitance (CPE-Ti) were decreased.

Conclusions

Therefore, EIS can be used as an effective method to monitor blood and RBC abnormalities caused by lead exposure. The electrical properties of the cells can be applied as an important observation in the evaluation of the toxic effects of heavy metals.

Hemolytic jaundice induced by pharmacological dose ascorbic acid in glucose-6-phosphate dehydrogenase deficiency: A case report

RATIONALE

Hemolysis induced by high dose ascorbic acid (AA) in patients with G6PD deficiency has been reported, but is rare. To our knowledge, this is the first reported case of a male with G6PD deficiency, coexpressed with cholecystolithiasis and cholecystitis, who developed extreme hemolysis and hyperbilirubinemia after receiving pharmacological doses ascorbic acid infusion.

PATIENT CONCERNS

A 27-year-old man history with glucose-6-phosphate dehydrogenase deficiency was admitted to our hospital because of cholecystolithiasis and cholecystitis. He appeared with scleral jaundice and very deep colored urine after receiving pharmacological doses ascorbic acid infusion.

DIAGNOSES

Clinical findings when combined with his medical history and various laboratory results confirmed the diagnosis as hemolysis and hyperbilirubinemia induced by ascorbic acid.

INTERVENTIONS

The patient was treated with steroids, hepatoprotective drugs, and folic acid in addition avoidance of agents with known hemolysis risk (such as vitamin C).

OUTCOMES

As a result, the patient's symptoms from hemolytic jaundice improved, hemoglobin remained stable, and the patient was discharged 11 days later.

LESSONS

Clinicians should bear in mind the possibility that vitamin C exposure may result in hemolysis in patients with G6PD deficiency, especially in those with known severe disease.

Design and Utility of a Point-of-Care Microfluidic Platform to Assess Hematocrit and Blood Coagulation

Purpose—

To develop a small volume whole blood analyzer capable of measuring the hematocrit and coagulation kinetics of whole blood.

Methods and Results—

A co-planar microfluidic chamber designed to facilitate self-driven capillary action across an internal electrical chip was developed and used to measure the electric parameters of whole human blood that had been anticoagulated or allowed to clot. To promote blood clotting, select chip surfaces were coated with a prothrombin time (PT) reagent containing lipidated tissue factor (TF), which activates the extrinsic pathway of coagulation to promote thrombin generation and fibrin formation. Whole human blood was added to the microfluidic device, and voltage changes within the platform were measured and interpreted using basic resistor-capacitor (RC) circuit and fluid dynamics theory. Upon wetting of the sensing zone, a circuit between two co-planar electrodes within the sensing zone was closed to generate a rapid voltage drop from baseline. The voltage then rose due to sedimentation of red blood cells (RBC) in the sensing zone. For anticoagulated blood samples, the time for the voltage to return to baseline was dependent on hematocrit. In the presence of coagulation, the initiation of fibrin formation in the presence of the PT reagent prevented the return of voltage to baseline due to the reduced packing of RBCs in the sensing zone.

Conclusions—

The technology presented in this study has potential for monitoring the hematocrit and coagulation parameters of patient samples using a small volume of whole blood, suggesting it may hold clinical utility as a point-of-care test.

Individual variability in response to a single sickling event for normal, sickle cell, and sickle trait erythrocytes

Hemoglobin S (Hb-S) polymerization is the primary event in sickle cell disease causing irreversible damage to red blood cell (RBC) membranes over repeated polymerization cycles. A single polymerization triggered by a hypoxic environment was reported to result in reversibly (upon reoxygenation) decreased RBC deformability and increased mechanical fragility (MF). Individualized responses have not been reported, although RBC fragility can vary significantly even among healthy individuals. This study evaluates individual variability in response to a single hypoxia-induced sickling event, through changes in RBC MF. Blood was drawn from 10 normal (AA), 11 sickle cell (SS), and 7 sickle trait (AS) subjects-with Hb-S fraction, osmotic fragility, and medical history also collected. Mechanical stress was applied using a bead mill at 50-Hz oscillation for 0.5-30 minutes. MF profiles here give percent hemolysis upon successive durations of stressing. MF was measured for AA, SS, and AS cells-each equilibrated (1) with air, (2) with nitrogen in an anaerobic chamber, and (3) with air after the hypoxic event. While AA subjects exhibited significantly different changes in fragility upon hypoxia, in all cases there was recovery to close to the initial MF values on reoxygenation. For AS subjects, recovery at reoxygenation was observed only in about half of the cases. Fragility of SS cells increased in hypoxia and decreased with reoxygenation, with significantly variable magnitude of recovery. The variability of response for individual AS and SS subjects indicates that some are potentially at higher risk of irreversible hypoxia-induced membrane damage.

Age-dependent detection of erythrocytes glucose-6-phosphate dehydrogenase and its correlation with oxidative stress

CONTEXT

Glucose-6-phosphate dehydrogenase (G6PD) is an important enzyme of hexose monophosphate shunt, involved in the biosynthesis of reduced nicotinamide adenine dinucleotide phosphate hydrogen (NADPH).

OBJECTIVE

This study was designed to investigate age-dependent changes in human erythrocyte G6PD activity. The G6PD activity pattern was correlated with reduced glutathione (GSH) and total antioxidant potential in terms of FRAP (ferric reducing ability of plasma) value.

MATERIALS AND METHODS

We analyzed normal, healthy subjects of both sexes between the ages of 20 and 80 years. G6PD activity was determined by Burties method.

RESULTS

We observe a significant age-dependent decrease in G6PD activity (p < 0.0001). It was positively correlated with GSH (r = 0.5706) and total antioxidant potential (r = 0.7723) as a function of human age.

DISCUSSION AND CONCLUSION

Our findings on erythrocyte G6PD and their correlation with GSH and FRAP provide evidence of a higher oxidative stress in old age population.