Search Results (33)

Adenoviral vector vaccines were pivotal for COVID-19 control, but postmarketing safety surveillance has identified venous-predominant thrombotic risks not fully explained by platelet-centric mechanisms. We tested an RBC-associated hypothesis using an Ad5 vector-rAd/HA(PR8) rat model within a predefined sub-hemolytic window (<10% hemolysis). Ex vivo, we quantified RBC surface phosphatidylserine (PS) exposure, morphology remodeling by scanning electron microscopy, and microvesicle generation, all aligning with increased procoagulant activity. RBCs also exhibited dose-dependent increases in thrombin generation 4 h after intravenous exposure (10⁸–10⁹ OPU/Rat). In vivo, an inferior vena cava thrombosis model showed a pronounced, dose-responsive rise in thrombus burden, consistent with increased thrombogenic potential. Together, these integrated data provide experimental evidence consistent with RBC involvement under adenoviral exposure, supporting a biologically plausible link to the venous-predominant epidemiology observed during the COVID-19 vaccination era. Reported clinical adenoviral vaccine doses are of the same order of magnitude as the exposures tested here, supporting translational relevance while not implying inter-species or product equivalence. Incorporating RBC-focused endpoints, including PS exposure, morphology indices, microvesicle counts, and thrombin generation, into preclinical and early clinical assessments may enhance safety evaluation and inform vector design to mitigate venous thrombotic risk. Full article

Bee venom (BV) molecules, including melittin (Mlt), are known to modify the permeability of membranes. This paper assessed red blood cell (RBC) shape (by phase contrast microscopy) in relation to some of the parameters (haematology data) and calculated the RBC membranes’ water diffusional permeability (P_d) with ¹H-NMR spectroscopy. Rats were injected for 30 days with either small daily doses of BV (VST) or Mlt (MST) or with high single doses of BV (VSLT) or Mlt (MSLT). The RBCs displayed aberrant shapes, all of the analysed parameters significantly changed, and the values of P_d were higher (and increased with temperature) in all of the treated groups compared to the control group. The RBCs in the venom-treated groups had the highest mean values (expressed in cm × s⁻¹ × 10³) of P_d at 37 °C—8.95 in the VSLT group and 8.69 in the VST group—which were followed by the MST and MSLT groups and the control group. Our results demonstrated the ability of Mlt to retain the ability to interact with the RBC membrane in vivo and proved that Mlt is the most important BV molecule involved in this process. Full article

Background/Objectives: The prevalence of obesity worldwide has rapidly increased. Numerous studies showed a beneficial effect of probiotics in obese individuals, and changes in hematological parameters are observed in obesity. Therefore, the aim of this study was to investigate the effect of a novel probiotic approach on the red blood cells (RBCs) and platelets. Methods: Twenty-five obese women participated in a randomized, placebo-controlled study and were divided into the experimental group (one capsule daily containing Lactiplantibacillus plantarum 299v (DSM9843), Saccharomyces cerevisiae var. boulardii, and 40 mg octacosanol; n = 13) and the placebo group (n = 12). Blood samples were collected for light microscopic examination, morphometric analysis, and an automated hematology analyzer. A possible relationship between hematological parameters and body mass index (BMI), a common indicator of obesity, was investigated using Spearman correlation. The plasma concentration of soluble P-selectin and fibrinogen were determined using an ELISA assay. All measurements were performed before (T0) and after 12 weeks of supplementation (T1). Results: The three-month supplementation of probiotics improved hemoglobin levels, chromic status, and red blood cell morphology. The mean platelet volume (MPV), a measure of platelet size, was restored to normal levels, platelet morphology was improved, and the number of activated platelets was significantly reduced (p < 0.05). A strong negative correlation (r = −0.5904, p < 0.05) was found between BMI and platelet distribution width (PDW), a measure of variation in platelet size and shape. Conclusions: The results show that the probiotic approach improves morphology and normalizes the values of disturbed hematological parameters of RBCs and platelets in obese women. Full article

Nature equipped red blood cells (RBCs) with diverse mechanical properties, which makes it possible to examine blood with different RBC properties (size, shape, aggregability, deformability). We investigated whether the shelf life of cow blood (stiff RBCs, low aggregability) is longer compared with pig blood (deformability/aggregability comparable to human) due to a delay in RBC clustering and decomposition. Blood was drawn from conscious pigs and cows in their familiar environment to reduce stress and stored 30 days at +7 °C. RBCs remained intact in cow samples whereas pig samples became hemolytic after day 20. White blood cells and platelets decreased with similar percentages in both species. Hematocrit (HCT) decreased due to RBC shrinking in bovine samples and due to RBC decay in porcine samples. Blood viscosity increased in both species although HCT decreased. In porcine samples, shear thinning decreased progressively, indicating a gradual loss of sample cohesion with storage. Yield stress and storage modulus decreased with hemolysis. In HCT-native cow samples, shear thinning, yield stress, and storage modulus showed high intraindividual variability, but the mean values did not change over the time course. In HCT-adjusted (38%) cow samples, solidification occurred after day 7, followed by a reduction in cohesion and shear thinning until the end of storage. Full article

This study evaluates the antiproliferative potential of flavanones, chromanones and their spiro-1-pyrazoline derivatives as well as their inclusion complexes. The main goal was to determine the biological basis of molecular pro-apoptotic activities and the participation of reactive oxygen species (ROS) in shaping the cytotoxic properties of the tested conjugates. For this purpose, changes in mitochondrial potential and the necrotic/apoptotic cell fraction were analyzed. Testing with specific fluorescent probes found that ROS generation had a significant contribution to the biological anticancer activity of complexes of flavanone analogues. TT (thrombin time), PT (prothrombin time) and APTT (activated partial tromboplastin time) were used to evaluate the influence of the compounds on the extrinsic and intrinsic coagulation pathway. Hemolysis assays and microscopy studies were conducted to determine the effect of the compounds on RBCs. Full article

The deformability of red blood cells (RBCs), expressing their ability to change their shape as a function of flow-induced shear stress, allows them to optimize oxygen delivery to the tissues and minimize their resistance to flow, especially in microcirculation. During physiological aging and blood storage, or under external stimulations, RBCs undergo metabolic and structural alterations, one of which is hemoglobin (Hb) redistribution between the cytosol and the membrane. Consequently, part of the Hb may attach to the cell membrane, and although this process is reversible, the increase in membrane-bound Hb (MBHb) can affect the cell’s mechanical properties and deformability in particular. In the present study, we examined the correlation between the MBHb levels, determined by mass spectroscopy, and the cell deformability, determined by image analysis. Six hemoglobin subunits were found attached to the RBC membranes. The cell deformability was negatively correlated with the level of four subunits, with a highly significant inter-correlation between them. These data suggest that the decrease in RBC deformability results from Hb redistribution between the cytosol and the cell membrane and the respective Hb interaction with the cell membrane. Full article

Absorption spectra of red blood cell (RBC) suspensions are investigated in an osmolarity range in the medium from 200 mOsm to 900 mOsm. Three spectral parameters are used to characterize the process of swelling or shrinkage of RBC—the absorbance at 700 nm, the Soret peak height relative to the spectrum background, and the Soret peak wavelength. We show that with an increase in the osmolarity, the absorbance at 700 nm increases and the Soret peak relative height decreases. These changes are related to the changes in the RBC volume and the resulting increase in the hemoglobin intracellular concentration and index of refraction. Confocal microscopy and flow cytometry measurements supported these conclusions. The maximum wavelength of the Soret peak increases with increasing osmolarity due to changes in the oxygenation state of hemoglobin. Using these spectrum parameters, the process of osmosis in RBCs can be followed in real time, but it can also be applied to various processes, leading to changes in the volume and shape of RBCs. Therefore, we conclude that UV–Vis absorption spectrophotometry offers a convenient, easily accessible, and cost-effective method to monitor changes in RBC, which can find applications in the field of drug discovery and diagnostics of RBC and hemoglobin disorders. Full article

Adenine nucleotides play a critical role in maintaining essential functions of red blood cells (RBCs), including energy metabolism, redox status, shape fluctuations and RBC-dependent endothelial and microvascular functions. Recently, it has been shown that infection with the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) might lead to morphological and metabolic alterations in erythrocytes in both mild and severe cases of coronavirus disease (COVID-19). However, little is known about the effects of COVID-19 on the nucleotide energetics of RBCs nor about the potential contribution of nucleotide metabolism to the long COVID syndrome. This study aimed to analyze the levels of adenine nucleotides in RBCs isolated from patients 12 weeks after mild SARS-CoV-2 infection who suffered from long COVID symptoms and to relate them with the endothelial and microvascular function parameters as well as the rate of peripheral tissue oxygen supply. Although the absolute quantities of adenine nucleotides in RBCs were rather slightly changed in long COVID individuals, many parameters related to the endothelial and microcirculatory function showed significant correlations with RBC adenosine triphosphate (ATP) and total adenine nucleotide (TAN) concentration. A particularly strong relationship was observed between ATP in RBCs and the serum ratio of arginine to asymmetric dimethylarginine—an indicator of endothelial function. Consistently, a positive correlation was also observed between the ATP/ADP ratio and diminished reactive hyperemic response in long COVID patients, assessed by the flow-mediated skin fluorescence (FMSF) technique, which reflected decreased vascular nitric oxide bioavailability. In addition, we have shown that patients after COVID-19 have significantly impaired ischemic response parameters (IR max and IR index), examined by FMSF, which revealed diminished residual bioavailability of oxygen in epidermal keratinocytes after brachial artery occlusion. These ischemic response parameters revealed a strong positive correlation with the RBC ATP/ADP ratio, confirming a key role of RBC bioenergetics in peripheral tissue oxygen supply. Taken together, the outcomes of this study indicate that dysregulation of metabolic processes in erythrocytes with the co-occurring endothelial and microvascular dysfunction is associated with diminished intracellular oxygen delivery, which may partly explain long COVID-specific symptoms such as physical impairment and fatigue. Full article

A global interest in Silver Barb (Barbonymus gonionotus) cultivation has arisen because of a combination of declining wild stock and a steady increase in demand and market value. The purpose of the current investigation was to evaluate the impact of extreme water temperature changes on growth, hemato-biochemical responses, pepsin enzyme activity and gill histomorphology of B. gonionotus. Four distinct temperatures (22, 26, 30 and 34 °C) were applied in the laboratory (22, 26, 30 and 34 °C) in triplicate glass aquariums (150 L each). At 30 and 22 °C, respectively, the highest and the lowest length and weight gain, specific, daily and relative growth rates were noted. At 30 °C the lowest FCR was recorded (1.42 ± 0.04). The values related to hematology and biochemistry were found to be within normal ranges; nevertheless, there was a notable variation in the parameters when the temperature changed. Hematological results revealed that RBC, HB, PLT, HCT and PMV levels were significantly higher in groups 30 °C with respect to others. It was evident that cold and heat shock stress was present due to the decline in hematocrit levels and rise in WBC values. Regarding the biochemical responses, the level of triglycerides, cholesterol, AP, Ca⁺, HDL, and HDL/LDL ratio increased significantly higher at 30 °C. Glucose, total protein, albumin, Na⁺, K⁺, Cl⁻¹, AST, bilirubin, uric acid, and LDL levels were significantly higher at 22 °C compared to other temperatures. There was a higher pepsin activity between 26 and 30 °C while the digestive somatic index (I_DS) was disproportionate. Histological examination demonstrated the well-shaped gill tissues at 26 and 30 °C compared to distinctive pathology in other temperature treatments. As an end note, the results of the experiment indicated that B. gonionotus should be cultured at 26–30 °C to maximize the overall productivity and the health condition of this economically important fish species. Full article

(1) Background: Upconversion nanoparticles (UCNPs) are a promising tool for biological tissue structure visualization and photodynamic therapy (PDT). The luminescence of such NPs is excited in the spectrum’s near-infrared (NIR) region, while the NPs luminesce in the visible region. Conjugating such NPs with photodynamic dyes that absorb their luminescence makes it possible to increase the depth at which PDT is performed. (2) Methods: We conducted a comprehensive study on the possibility of using NaYF₄:Er:Yb UCNPs in vivo for imaging and PDT. The NPs were synthesized by a hydrothermal method. The synthesis of NPs with a size of 80 nm and hexagonal structure was demonstrated. (3) Results: The accumulation of NPs in organs after their intravenous injection into rats was studied. The effect of NPs on the shape, size, and degree of aggregation of red blood cells (RBC) was also investigated. (4) Conclusions: The possibility of luminescent visualization of NPs in histological sections and their subcutaneous distribution is demonstrated. All investigated particles showed moderate toxicity, causing mostly reversible changes. Full article

Sepsis is a life-threatening multiple-organ dysfunction induced by infection and is one of the leading causes of mortality and critical illness worldwide. The pathogenesis of sepsis involves the alteration of several biochemical pathways such as immune response, coagulation, dysfunction of endothelium and tissue damage through cellular death and/or apoptosis. Recently, in vitro and in vivo studies reported changes in the morphology and in the shape of human red blood cells (RBCs) causing erythrocyte death (eryptosis) during sepsis. Characteristics of eryptosis include cell shrinkage, membrane blebbing, and surface exposure to phosphatidylserine (PS), which attract macrophages. The aim of this study was to evaluate the in vitro induction of eryptosis on healthy RBCs exposed to septic plasma at different time points. Furthermore, we preliminary investigated the in vivo levels of eryptosis in septic patients and its relationship with Endotoxin Activity Assay (EAA), mortality and other biological markers of inflammation and oxidative stress. We enrolled 16 septic patients and 16 healthy subjects (no systemic inflammation in the last 3 months) as a control group. At diagnosis, we measured Interleukin-6 (IL-6) and Myeloperoxidase (MPO). For in vitro study, healthy RBCs were exposed to the plasma of septic patients and CTR for 15 min, 1, 2, 4 and 24 h. Morphological markers of death and eryptosis were evaluated by flow cytometric analyses. The cytotoxic effect of septic plasma on RBCs was studied in vitro at 15 min, 1, 2, 4 and 24 h. Healthy RBCs incubated with plasma from septic patients went through significant morphological changes and eryptosis compared to those exposed to plasma from the control group at all time points (all, p < 0.001). IL-6 and MPO levels were significantly higher in septic patients than in controls (both, p < 0.001). The percentage of AnnexinV-binding RBCs was significantly higher in septic patients with EAA level ≥0.60 (positive EAA: 32.4%, IQR 27.6–36.2) compared to septic patients with EAA level <0.60 (negative EAA: 14.7%, IQR 5.7–30.7) (p = 0.04). Significant correlations were observed between eryptosis and EAA levels (Spearman rho2 = 0.50, p < 0.05), IL-6 (Spearman rho2 = 0.61, p < 0.05) and MPO (Spearman rho2 = 0.70, p < 0.05). In conclusion, we observed a quick and great cytotoxic effect of septic plasma on healthy RBCs and a strong correlation with other biomarkers of severity of sepsis. Based on these results, we confirmed the pathological role of eryptosis in sepsis and we hypothesized its use as a biomarker of sepsis, potentially helping physicians to face important treatment decisions. Full article

Red blood cell (RBC) deformability, expressing their ability to change their shape, allows them to minimize their resistance to flow and optimize oxygen delivery to the tissues. RBC with reduced deformability may lead to increased vascular resistance, capillary occlusion, and impaired perfusion and oxygen delivery. A reduction in deformability, as occurs during RBC physiological aging and under blood storage, is implicated in the pathophysiology of diverse conditions with circulatory disorders and anemias. The change in RBC deformability is associated with metabolic and structural alterations, mostly uncharacterized. To bridge this gap, we analyzed the membrane protein levels, using mass spectroscopy, of RBC with varying deformability determined by image analysis. In total, 752 membrane proteins were identified. However, deformability was positively correlated with the level of only fourteen proteins, with a highly significant inter-correlation between them. These proteins are involved in membrane rafting and/or the membrane–cytoskeleton linkage. These findings suggest that the reduction of deformability is a programmed (not arbitrary) process of remodeling and shedding of membrane fragments, possibly mirroring the formation of extracellular vesicles. The highly significant inter-correlation between the deformability-expressing proteins infers that the cell deformability can be assessed by determining the level of a few, possibly one, of them. Full article

A spontaneous mutant of the duckweed Lemna gibba clone no. 7796 (known as strain G3, WT) was discovered. In this mutant clone, L. gibba clone no. 9602 (mt), the morphological parameters (frond length, frond width, root length, root diameter) indicated an enlarged size. A change in the frond shape was indicated by the decreased frond length/width ratio, which could have taxonomic consequences. Several different cell types in both the frond and the root were also enlarged. Flow cytometric measurements disclosed the genome size of the WT as 557 Mbp/1C and that of the mt strain as 1153 Mbp/1C. This represents the results of polyploidisation of a diploid clone to a tetraploid one. The mutant clone flowered under the influence of long day-treatment in half-strength Hutner’s medium in striking contrast to the diploid WT. Low concentration of salicylic acid (<1 µM) induced flowering in the tetraploid mutant but not in the diploid plants. The transcript levels of nuclear-encoded genes of the photosynthetic apparatus (CAB, RBCS) showed higher abundance in light and less dramatic decline in darkness in the mt than in WT, while this was not the case with plastid-encoded genes (RBCL, PSAA, PSBA, PSBC). Full article

Blood flow in the microcirculatory system is crucially affected by intrinsic red blood cell (RBC) properties, such as their deformability. In the smallest vessels of this network, RBCs adapt their shapes to the flow conditions. Although it is known that the age of RBCs modifies their physical properties, such as increased cytosol viscosity and altered viscoelastic membrane properties, the evolution of their shape-adapting abilities during senescence remains unclear. In this study, we investigated the effect of RBC properties on the microcapillary in vitro flow behavior and their characteristic shapes in microfluidic channels. For this, we fractioned RBCs from healthy donors according to their age. Moreover, the membranes of fresh RBCs were chemically rigidified using diamide to study the effect of isolated graded-membrane rigidity. Our results show that a fraction of stable, asymmetric, off-centered slipper-like cells at high velocities decreases with increasing age or diamide concentration. However, while old cells form an enhanced number of stable symmetric croissants at the channel centerline, this shape class is suppressed for purely rigidified cells with diamide. Our study provides further knowledge about the distinct effects of age-related changes of intrinsic cell properties on the single-cell flow behavior of RBCs in confined flows due to inter-cellular age-related cell heterogeneity. Full article

Background: To evaluate the effect of different experimental staining procedures on color stability and translucency of a nano-hybrid resin-based composite (RBC). Methods: Forty-eight cylindrical-shaped specimens (10 × 2 mm) were prepared with a nano-hybrid RBC (Clearfil Majesty ES-2) and randomly divided in four groups according to the experimental staining procedure: G1) static immersion in a staining solution (coffee) (44 ± 1 °C); G2) staining cycling between coffee (44 ± 1°C) and distilled water (37 ± 1°C) with an experimental staining machine based on Arduino, an Open Source hardware development platform; G3) staining cycles as in G2 + brushing with a low abrasive toothpaste (Relative Dentin Abrasion RDA = 30) (Elmex Sensitive Professional); G4) staining cycles as in G3, with brushing performed with a very strong abrasive toothpaste (RDA = 90) (Lacult Active). Color parameters were recorded at the baseline (T0) after staining procedures (T1) and repolishing (T2) using a spectrophotometer. Color change (∆E00) and translucency (TP, CR) were evaluated. Data were statistically analyzed (p < 0.05). Results: For ∆E00 after staining, Group 1 showed the highest color change and Group 3 the lowest. All groups were significantly different (p < 0.001) except for Group 2 vs. Group 4; after repolishing, Group 1 was significantly higher than Group 3 (p < 0.001), Group 2 (p < 0.001), and Group 4 (p = 0.003); Group 2 was higher than Group 3 (p < 0.001). For TP variable, after staining procedures, Group 2 was significantly higher than all other groups (p < 0.001), and Group 1 was significantly higher than Group 3 (p < 0.001) and Group 4 (p = 0.007). After repolishing, Group 4 was significantly lower than Group 3 (p = 0.008) and Group 2 (p = 0.027). Repolishing procedure significantly reduced color parameters. Conclusions: The investigated staining procedure induced significant differences in color stability and translucency. The use of a very strong abrasive toothpaste (RDA = 90) induced higher color change than a low abrasive one (RDA = 30). Repolishing procedures are able to partially reduce color change induced by artificial staining procedures. Full article