Atomic force microscopy study of red blood cell membrane nanostructure during oxidation-reduction processes

Hemoglobin Derivatives in Beef Irradiated with Accelerated Electrons

The efficiency of food irradiation depends on the accuracy of the irradiation dose range that is sufficient for inhibiting microbiological growth without causing an irreversible change to the physical and chemical properties of foods. This study suggests that the concentration of hemoglobin derivatives can be used as a criterion for establishing the limit for chilled beef irradiation at which irradiation-induced oxidation becomes irreversible. The express spectrophotometry method for estimating the hemoglobin derivative concentration shows a nonlinear increase in methemoglobin concentration from 15% to 50% in beef irradiated by accelerated electrons with the doses ranging from 250 Gy to 10,000 Gy. The monitoring of the hemoglobin derivative concentration for three days after irradiation shows nonmonotonous dependencies of methemoglobin concentration in beef in the storage time since the oxidation of hemoglobin occur as a result of irradiation and biochemical processes in beef during storage. The proposed method based on the quantitative analysis of the hemoglobin derivative concentration can be used to estimate the oxidation level for irradiation of foods containing red blood cells. The study proposes a model that describes the change in hemoglobin derivative concentration in beef after irradiation considering that oxidation of hemoglobin can be triggered by the direct ionization caused by accelerated electrons, biochemical processes as a result of bacterial activity, and reactive oxygen species appearing during irradiation and storage. This research throws light on the mechanisms behind food irradiation during storage that should be taken into account for selecting the optimal parameters of irradiation.

A Proposed New Model to Explain the Role of Low Dose Non-DNA Targeted Radiation Exposure in Chronic Fatigue and Immune Dysfunction Syndrome

Chronic Fatigue and Immune Dysfunction Syndrome (CFIDS) is considered to be a multidimensional illness whose etiology is unknown. However, reports from Chernobyl, as well as those from the United States, have revealed an association between radiation exposure and the development of CFIDS. As such, we present an expanded model using a systems biology approach to explain the etiology of CFIDS as it relates to this cohort of patients. This paper proposes an integrated model with ionizing radiation as a suggested trigger for CFIDS mediated through UVA induction and biophoton generation inside the body resulting from radiation-induced bystander effects (RIBE). Evidence in support of this approach has been organized into a systems view linking CFIDS illness markers with the initiating events, in this case, low-dose radiation exposure. This results in the formation of reactive oxygen species (ROS) as well as important immunologic and other downstream effects. Furthermore, the model implicates melanoma and subsequent hematopoietic dysregulation in this underlying process. Through the identification of this association with melanoma, clinical medicine, including dermatology, hematology, and oncology, can now begin to apply its expansive knowledge base to provide new treatment options for an illness that has had few effective treatments.

Mechanochemical Synergism of Reactive Oxygen Species Influences on RBC Membrane

The influences of various factors on blood lead to the formation of extra reactive oxygen species (ROS), resulting in the disruption of morphology and functions of red blood cells (RBCs). This study considers the mechanisms of the mechanochemical synergism of OH• free radicals, which are most active in the initiation of lipid peroxidation (LPO) in RBC membranes, and H2O2 molecules, the largest typical diffusion path. Using kinetic models of differential equations describing CH2O2t and COH•t, we discuss two levels of mechanochemical synergism that occur simultaneously: (1) synergism that ensures the delivery of highly active free radicals OH• to RBC membranes and (2) a positive feedback system between H2O2 and OH•, resulting in the partial restoration of spent molecules. As a result of these ROS synergisms, the efficiency of LPO in RBC membranes sharply increases. In blood, the appearance of OH• free radicals is due to the interaction of H2O2 molecules with free iron ions (Fe2+) which arise as a result of heme degradation. We experimentally established the quantitative dependences of COH• CH2O2 using the methods of spectrophotometry and nonlinear curve fitting. This study extends the analysis of the influence of ROS mechanisms in RBC suspensions.

The Toxic Influence of Excess Free Iron on Red Blood Cells in the Biophysical Experiment: An In Vitro Study

Iron is needed for life-essential processes, but free iron overload causes dangerous clinical consequences. The study of the role of red blood cells (RBCs) in the influence of excess free iron in the blood on the pathological consequences in an organism is relevant. Here, in a direct biophysical experiment in vitro, we studied the action of free iron overload on the packed red blood cell (pRBC) characteristics. In experiments, we incubated pRBCs with the ferrous sulfate solution (Fe²⁺). Wе used free iron in a wide range of concentrations. High Fe²⁺ concentrations made us possible to establish the pattern of the toxic effect of excess iron on pRBCs during a reduced incubation time in a biophysical experiment in vitro. It was found that excess free iron causes changes in pRBC morphology, the appearance of bridges between cells, and the formation of clots, increasing the membrane stiffness and methemoglobin concentration. We created a kinetic model of changes in the hemoglobin derivatives. The complex of simultaneous distortions of pRBCs established in our experiments can be taken into account when studying the mechanism of the toxic influence of excess free iron in the blood on pathological changes in an organism.

Nanoscale Changes on RBC Membrane Induced by Storage and Ionizing Radiation: A Mini-Review

The storage lesions and the irradiation of blood cellular components for medical procedures in blood banks are events that may induce nanochanges in the membrane of red blood cells (RBCs). Alterations, such as the formation of pores and vesicles, reduce flexibility and compromise the overall erythrocyte integrity. This review discusses the alterations on erythrocytic lipid membrane bilayer through their characterization by confocal scanning microscopy, Raman, scanning electron microscopy, and atomic force microscopy techniques. The interrelated experimental results may address and shed light on the correlation of biomechanical and biochemical transformations induced in the membrane and cytoskeleton of stored and gamma-irradiated RBC. To highlight the main advantages of combining these experimental techniques simultaneously or sequentially, we discuss how those outcomes observed at micro- and nanoscale cell levels are useful as biomarkers of cell aging and storage damage.

Two-step process of cytoskeletal structural damage during long-term storage of packed red blood cells

BACKGROUND

Storage of packed red blood cells (PRBC) for 42 days causes morphological, structural, and functional changes in the red cells. To assess the quality of stored PRBC, it is important to evaluate the main components of the product. The aim of this study was to evaluate the kinetics of the structural transformations in the cytoskeleton of red cells during long-term storage (up to 42 days).

MATERIALS AND METHODS

Bags of PRBC were stored with CPD/SAGM solution at +4 °C. Cytoskeletal parameters were measured on days 3, 12, 19, 21, 24, 28, 35, and 42 of storage to determine their changes. Atomic force microscopy was used to obtain images and analyse the parameters of the cytoskeletal network. As the storage time increased, a general PRBC test was performed. Membrane fixatives were not used at any stage of the preparation of the specimens for cytoskeletal imaging.

RESULTS

When PRBC were stored for 42 days, the main changes to the cytoskeletal mesh included rupture of filaments, merger of small pores into larger ones, a decrease of the number of pores, thickening of filaments, and an increase of membrane stiffness. A process of irreversible changes to the cytoskeleton started on days 19-21. A kinetic model of changes in the parameters of the cytoskeletal mesh with time of PRBC storage was created.

DISCUSSION

Two stages of impairment in cytoskeletal elements were found: rupture of filaments and clustering of protein components. The typical time of development and specifics of these stages are discussed. The consequences of the altered configuration of the cytoskeleton are also discussed. Destruction of the red cell cytoskeleton can have a negative effect on the efficacy of blood transfusion and increase the risk of post-transfusion complications. Our findings can be used in clinical medicine to evaluate the quality of PRBC for blood transfusion as well as for studies of the molecular organisation of red cells undergoing various types of physical and chemical treatment.

Assessment of carboxyhemoglobin content in the blood with high accuracy: wavelength range optimization for nonlinear curve fitting of optical spectra

The impact of carbon monoxide (CO) gas on the human organism is very dangerous. The affinity of CO to hemoglobin is considerably higher than that of oxygen. Thus, the interaction of CO with the blood results in a higher content of carboxyhemoglobin (HbCO) in red blood cells (RBCs) and correspondingly in tissue hypoxia. The disruption in the organism depends on the HbCO content in the blood. To assess any complications in the body at a given moment due to CO exposure and predict future consequences, it is necessary to measure the dynamics of hemoglobin derivative concentrations simultaneously. However, measuring HbCO and other derivatives in RBCs without hemolysis accurately is complicated due to the strong intercollinearity between the molar absorptivities of hemoglobin derivatives and superposition of absorption and scattering spectra. In the present study, to quantitatively assess the contents of the hemoglobin derivatives in the blood after exposure to CO, improved accuracy is achieved by optimizing the wavelength range used for the nonlinear curve fitting of optical spectra. Experimental spectra were measured in the wavelength range Δλ=500−700nm. For each experimental curve, it was established the value of optimal interval Δλopt for which the correlation coefficient between experimental data and corresponding points of the theoretical fitting curve was the maximum in the wavelength range Δλtyp=535−580nm, which contains the typical absorption peaks for HbO2, Hb, and HbCO. The concentrations obtained based on such fitting curves were considered to be highly accurate. The quantitative assessment enabled the determination of theHbCO nonlinear increase with the time of CO exposure in the in vitro experiment and the study of the dynamics of hemoglobin derivative transformations during blood incubation.

Multimodal detection and analysis of a new type of advanced Heinz body-like aggregate (AHBA) and cytoskeleton deformation in human RBCs

A new type of aggregate, formed in human red blood cells (RBCs) in response to glutaraldehyde treatment, was discovered and analyzed with the classical and advanced biomolecular imaging techniques. Advanced Heinz body-like aggregates (AHBA) formed in a single human RBC are characterized by a higher level of hemoglobin (Hb) degradation compared to typical Heinz bodies, which consist of hemichromes. The complete destruction of the porphyrin structure of Hb and the aggregation of the degraded proteins in the presence of Fe³⁺ ions are observed. The presence of such aggregated, highly degraded proteins inside RBCs, without cell membrane destruction, has been never reported before. For the first time the spatial differentiation of two kinds of protein mixtures inside a single RBC, with different phenylalanine (Phe) conformations, is visualized. The non-resonant Raman spectra of altered RBCs with AHBA are characterized by the presence of a strong band located at 1037 cm^-1, which confirms that glutaraldehyde interacts strongly with Phe. The shape-shifting of RBCs from a biconcave disk to a spherical structure and sinking of AHBA to the bottom of the cell are observed. Results reveal that the presence of AHBA should be considered when fixing RBCs and indicate the analytical potential of Raman spectroscopy, atomic force microscopy and scanning near-field optical microscopy in AHBA detection and analysis.

Conformational Distortions of the Red Blood Cell Spectrin Matrix Nanostructure in Response to Temperature Changes In Vitro

The spectrin matrix is a structural element of red blood cells (RBCs). As such, it affects RBC morphology, membrane deformability, nanostructure, stiffness, and, ultimately, the rheological properties of blood. However, little is known about how temperature affects the spectrin matrix. In this study, the nanostructure of the spectrin network was recorded by atomic force microscopy. We describe how the nanostructure of the RBC spectrin matrix changes from a regular network to a chaotic pattern following an increase in temperature from 20 to 50°C. At 20-37°С, the spectrin network formed a regular structure with dimensions of typically 150 ± 60 nm. At 42-43°С, 83% of the spectrin network assumed an irregular structure. Finally, at 49-50°С the chaotic pattern was observed, and no quantitative estimates of the spectrin structure's parameters could be made. These results can be useful for biophysical studies on the destruction of the spectrin network under pathological conditions, as well as for investigating cell morphology and blood rheology in different diseases.