Intelligent berberine-loaded erythrocytes attenuated inflammatory cytokine productions in macrophages

Erythrocytes are impressive tools for drug delivery, especially to macrophages. Therefore, berberine was loaded into erythrocytes using both hypotonic pre-swelling and endocytosis methods to target macrophages. Physicochemical and kinetic parameters of the resulting carrier cells, such as drug loading/release kinetics, osmotic fragility, and hematological indices, were determined. Drug loading was optimized for the study using Taguchi experimental design and lab experiments. Loaded erythrocytes were targeted to macrophages using ZnCl2 and bis-sulfosuccinimidyl-suberate, and targeting was evaluated using flow cytometry and Wright-Giemsa staining. Differentiated macrophages were stimulated with lipopolysaccharide, and the inflammatory profiles of macrophages were evaluated using ELISA, western blotting, and real-time PCR. Findings indicated that the endocytosis method is preferred due to its low impact on the erythrocyte's structural integrity. Maximum loading achieved (1386.68 ± 22.43 μg/ml) at 1500 μg/ml berberine treatment at 37 °C for 2 h. Berberine successfully inhibited NF-κB translation in macrophages, and inflammatory response markers such as IL-1β, IL-8, IL-23, and TNF-α were decreased by approximately ninefold, sixfold, twofold, eightfold, and twofold, respectively, compared to the LPS-treated macrophages. It was concluded that berberine-loaded erythrocytes can effectively target macrophages and modulate the inflammatory response.

Environmental cadmium exposure perturbs systemic iron homeostasis via hemolysis and inflammation, leading to hepatic ferroptosis in common carp (Cyprinus carpio L.)

Cadmium (Cd) pollution is considered a pressing challenge to eco-environment and public health worldwide. Although it has been well-documented that Cd exhibits various adverse effects on aquatic animals, it is still largely unknown whether and how Cd at environmentally relevant concentrations affects iron metabolism. Here, we studied the effects of environmental Cd exposure (5 and 50 μg/L) on iron homeostasis and possible mechanisms in common carp. The data revealed that Cd elevated serum iron, transferrin saturation and iron deposition in livers and spleens, leading to the disruption of systemic iron homeostasis. Mechanistic investigations substantiated that Cd drove hemolysis by compromising the osmotic fragility and inducing defective morphology of erythrocytes. Cd concurrently exacerbated hepatic inflammatory responses, resulting in the activation of IL6-Stat3 signaling and subsequent hepcidin transcription. Notably, Cd elicited ferroptosis through increased iron burden and oxidative stress in livers. Taken together, our findings provide evidence and mechanistic insight that environmental Cd exposure could undermine iron homeostasis via erythrotoxicity and hepatotoxicity. Further investigation and ecological risk assessment of Cd and other pollutants on metabolism-related effects is warranted, especially under the realistic exposure scenarios.

Effect of a single immersion in cold water below 4 °C on haemorheological properties of blood in healthy men

Cold water immersion (CWI) involves rapid cooling of the body, which, in healthy individuals, triggers a defence response to an extreme stimulus, to which the body reacts with stress. The aim of the study was to determine the effect of CWI on hemorheological blood indicators. The study group consisted of 13 young males. Blood samples were collected before and after CWI. The assessed parameters included the complete blood count, fibrinogen, hs-C-reactive protein (CRP), proteinogram, and blood rheology factors, such as erythrocyte elongation index (EI), half-time of total aggregation, and aggregation index. Additionally, the effect of reduced temperature on primary human vascular endothelium was investigated in vitro. CWI resulted in the decrease of body temperature to 31.55 ± 2.87 °C. After CWI, neutrophil count and mean corpuscular volume (MCV) were significantly increased in the study group, while lymphocyte count was significantly decreased. Significantly higher levels of total blood protein and albumin concentration were detected after the immersion. Among hemorheological characteristics, erythrocyte EIs at shear stress values ranging from 2.19 to 60.30 Pa were significantly lower after CWI. No significant changes in other rheological, morphological or biochemical parameters were observed. In vitro, human umbilical vein endothelial cells responded to 3 h of temperature decrease to 25 °C with unchanged viability, but increased recruitment of THP-1 monocytic cells and changes in cell morphology were observed. This was the first study to evaluate the effect of single CWI on rheological properties of blood in healthy young men. The results indicate that a single CWI may increase blood protein concentrations and worsen erythrocyte deformability parameters.

Small-molecule α-lipoic acid targets ELK1 to balance human neutrophil and erythrocyte differentiation

BACKGROUND

Erythroid and myeloid differentiation disorders are commonly occurred in leukemia. Given that the relationship between erythroid and myeloid lineages is still unclear. To find the co-regulators in erythroid and myeloid differentiation might help to find new target for therapy of myeloid leukemia. In hematopoiesis, ALA (alpha lipoic acid) is reported to inhibit neutrophil lineage determination by targeting transcription factor ELK1 in granulocyte-monocyte progenitors via splicing factor SF3B1. However, further exploration is needed to determine whether ELK1 is a common regulatory factor for erythroid and myeloid differentiation.

METHODS

In vitro culture of isolated CD34+, CMPs (common myeloid progenitors) and CD34+ CD371- HSPCs (hematopoietic stem progenitor cells) were performed to assay the differentiation potential of monocytes, neutrophils, and erythrocytes. Overexpression lentivirus of long isoform (L-ELK1) or the short isoform (S-ELK1) of ELK1 transduced CD34+ HSPCs were transplanted into NSG mice to assay the human lymphocyte and myeloid differentiation differences 3 months after transplantation. Knocking down of SRSF11, which was high expressed in CD371+GMPs (granulocyte-monocyte progenitors), upregulated by ALA and binding to ELK1-RNA splicing site, was performed to analyze the function in erythroid differentiation derived from CD34+ CD123mid CD38+ CD371- HPCs (hematopoietic progenitor cells). RNA sequencing of L-ELK1 and S-ELK1 overexpressed CD34+ CD123mid CD38+ CD371- HPCs were performed to assay the signals changed by ELK1.

RESULTS

Here, we presented new evidence that ALA promoted erythroid differentiation by targeting the transcription factor ELK1 in CD34+ CD371- hematopoietic stem progenitor cells (HSPCs). Overexpression of either the long isoform (L-ELK1) or the short isoform (S-ELK1) of ELK1 inhibited erythroid-cell differentiation, but knockdown of ELK1 did not affect erythroid-cell differentiation. RNAseq analysis of CD34+ CD123mid CD38+ CD371- HPCs showed that L-ELK1 upregulated the expression of genes related to neutrophil activity, phosphorylation, and hypoxia signals, while S-ELK1 mainly regulated hypoxia-related signals. However, most of the genes that were upregulated by L-ELK1 were only moderately upregulated by S-ELK1, which might be due to a lack of serum response factor interaction and regulation domains in S-ELK1 compared to L-ELK1. In summary, the differentiation of neutrophils and erythrocytes might need to rely on the dose of L-ELK1 and S-ELK1 to achieve precise regulation via RNA splicing signals at early lineage commitment.

CONCLUSIONS

ALA and ELK1 are found to regulate both human granulopoiesis and erythropoiesis via RNA spliceosome, and ALA-ELK1 signal might be the target of human leukemia therapy.

Hemocompatibility studies in nanotoxicology: Hemolysis or eryptosis? (A review)

Hemocompatibility evaluation is an important step in nanotoxicological studies. It is generally accepted that nanomaterials promote lysis of erythrocytes, blood clotting, alter phagocytosis, and upregulate pro-inflammatory cytokines. However, there are no standardized guidelines for testing nanomaterials hemocompatibility despite the fact that nanomaterials enter the bloodstream and interact with blood cells. In this review, the current knowledge on the ability of nanomaterials to induce distinct cell death modalities of erythrocytes is highlighted primarily focusing on hemolysis and eryptosis. This review aims to summarize the molecular mechanisms underlying erythrotoxicity of nanomaterials and critically compare the sensitivity and efficiency of hemolysis or eryptosis assays for nanomaterials blood compatibility testing. The list of eryptosis-inducing nanomaterials is growing, but it is still difficult to generalize how physico-chemical properties of nanoparticles affect eryptosis degree and molecular mechanisms involved. Thus, another aim of this review is to raise the awareness of eryptosis as a nanotoxicological tool to encourage the corresponding studies. It is worthwhile to consider adding eryptosis to in vitro nanomaterials hemocompatibility testing protocols and guidelines.

Fatty acids characterisation by GC-MS, antiglycation effect at multiple stages and protection of erythrocytes cells from oxidative damage induced by glycation of albumin of Opuntia ficus-indica (L.) Mill seed oil cultivated in Eastern Morocco: Experimental and computational approaches

ETHNOPHARMACOLOGICAL RELEVANCE

Opuntia ficus-indica (L.) Mill is frequently observed in the Moroccan traditional medicinal system, where these approaches are employed to mitigate the onset of diabetes and the subsequent complications it may entail.

AIM OF THE STUDY

The aim of this research was to examine the effectiveness of Opuntia ficus-indica seed oil in preventing diabetic complications. Specifically, the study assessed its ability to counteract glycation at various stages, protected red blood cells from the harmful effects of glycated albumin, and inhibited pancreatic lipase digestive enzymes to understand its potential antihyperglycemic properties. Additionally, the study aimed to identify the chemical components responsible for these effects, evaluate antioxidant and anti-inflammatory properties, and conduct computational investigations such as molecular docking.

MATERIALS AND METHODS

The assessement of Opuntia ficus-indica seed oil antiglycation properties involved co-incubating the extract oil with a bovine serum albumin-glucose glycation model. The study investigated various stages of glycation, incorporating fructosamine (inceptive stage), protein carbonyls (intermediate stage), and AGEs (late stage). Additionally, measurement of β-amyloid aggregation of albumin was performed using Congo red, which is specific to amyloid structures. Additionally, the evaluation of oil's safeguarding effect on erythrocytes against toxicity induced by glycated albumin included the measurement of erythrocyte hemolysis, lipid peroxidation, reduced glutathione. The fatty acid of Opuntia ficus-indica seed oil were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). The in vitro evaluation of antihyperglycemic activity involved the use of pancreatic lipase enzyme, while the assessement of antioxidant capability was carried out through the utilization of the ABTS and FRAP methods. The in vitro assessement of the denaturation of albumin activity was also conducted. In conjunction with the experimental outcomes, computational investigations were undertaken, specifically employing ADMET (absorption, distribution, metabolism, excretion, and toxicity) analysis. Furthermore, molecular docking was utilized to predict antioxidant and antiglycation mechanisms based on protein targets.

RESULTS

In vitro glycation assays, Opuntia ficus-indica seed oil displayed targeted inhibitory effects at multiple distinct stages. Within erythrocytes, in addition to mitigating hemolysis and lipid peroxidation induced by glycated albumin. GC-MS investigation revealed a richness of fatty acids and the most abundant compounds are Linoleic acid (36.59%), Palmitic acid (20.84%) and Oleic acid (19.33%) respectively. The findings of antioxidant ability showed a remarkable activity on FRAP and ABTS radicals. This oil showed a pronounced inhibitory impact (p < 0.001) on pancreatic lipase enzyme. It also exerted a notibale inhibition of albumin denaturation, in vitro.

CONCLUSION

The identified results were supported by the abundant compounds of fatty acids unveiled through GC-MS analysis, along with the computational investigation and molecular docking.

Blackcurrant press cake by-product: Increased chemical bioaccessibility and reduced antioxidant protection after in vitro simulation of gastrointestinal digestion

This study describes the bioaccessibility in terms of total phenolic content (TPC) and antioxidant capacity before and after in vitro digestion from blackcurrant press cake extracts (BPC) and the bioactivity in cell culture, human erythrocytes as well as the in silico analysis. Chemical analysis of BPC presented an increase in TPC (270%) and anthocyanins (136%) after in vitro digestion, resulting in an improvement of antioxidant activity (DPPH 112%; FRAP: 153%). This behavior may be related to the highest activity of cyanidin-3-rutinoside, as confirmed by in silico analysis. The digested BPC did not exert cytotoxicity in cells and showed less antioxidant activity against the oxidative damage induced in endothelial cells and human erythrocytes compared to the non-digested extract. The results raise a question about the reliability we should place on results obtained only from crude samples, especially those that will be used to produce foods or nutraceuticals.

A single coelomic cell type is involved in both immune and respiratory functions of the coastal bioindicator annelid: Capitella C-Channel1 from the English Channel

The polychaete Capitella is a typical member of the 'thiobiome', and is commonly used as an eutrophication indicator species in environmental assessment studies. To deal with a sulfide-rich and poisonous surrounding, cells in close contact with the environment, and thus able to play a major role in detoxication and survival, are circulating cells. This work aimed to morpho-functionally describe the circulating coelomic cells of Capitella from the English Channel inhabiting the sulfide-rich mud in Roscoff Harbor. In general, worms have three types of circulating cells, granulocytes involved in bacterial clearance and defense against microorganisms, eleocytes with an essentially trophic role and elimination of cellular waste, and erythrocytes which play a role in detoxification and respiration via their intracellular hemoglobin. By combining diverse microscopic and cellular approaches, we provide evidence that Capitella does not possess granulocytes and eleocytes, but rather a single abundant rounded cell type with the morphological characteristics of erythrocytes i.e. small size and production of intracellular hemoglobin. Surprisingly, our data show that in addition to their respiratory function, these red cells could exert phagocytic activities, and produce an antimicrobial peptide. This latter immune role is usually supported by granulocytes. Our data highlight that the erythrocytes of Capitella from the English Channel differ in morphology and bear more functions than the erythrocytes of other annelids. The simplicity of this multi-task (or polyvalent) single-cell type makes Capitella an interesting model for studies of the impact of the environment on the immunity of this bioindicator species.

Assessment of dietary polyvinylchloride, polypropylene and polyethylene terephthalate exposure in Nile tilapia, Oreochromis niloticus: Bioaccumulation, and effects on behaviour, growth, hematology and histology

Microplastics (MPs) have been recognized as emerging aquatic pollutants receiving major concern due to their detrimental effects on aquatic life. Nile Tilapia, Oreochromis niloticus is a model species considered in toxicological studies to address the effects of pollutants in freshwater animals. However, comprehensive knowledge comparing the impacts on fish across various MPs polymers is scarce. Therefore, the overarching aim of the current study was to examine the bioconcentration of MPs polymers: polyvinylchloride (PVC), polypropylene (PP), and polyethylene terephthalate (PET), and their toxic effects on growth, and behavioral responses, hematology, and histology of gills, liver, and intestine in O. niloticus. Fishes were subjected to a 21-day dietary exposure to MPs by assigning them into six treatment groups: T1 (4% of PVC), T2 (4% of PP), T3 (4% of PET), T4 (8% of PVC), T5 (8% of PP), T6 (8% of PET), and control (0% of MPs), to assess the effects on fish across the polymers and dosage. Results showed several abnormalities in anatomical and behavioral parameters, lower growth, and high mortality in MPs-exposed fish, indicating a dose-dependent relationship. The elevated dosage of polymers raised the bioavailability of PVC, PP, and PET in gills and gut tissues. Noteworthy erythrocyte degeneration referred to cytotoxicity and stress imposed by MPs, whereas the alterations in hematological parameters were possibly due to blood cell damage, also indicating mechanisms of defense against MPs toxicity. Histopathological changes in the gills, liver, and intestine confirmed the degree of toxicity and associated dysfunctions in fish. A higher sensitivity of O. niloticus to PET-MPs compared to other polymers is likely due to its chemical properties and species-specific morphological and physiological characteristics. Overall, the present study reveals valuable insights into the emerging threat of MPs toxicity in freshwater species, which could be supportive of future toxicological research.

Differences in serum and plasma levels of microRNAs and their time-course changes after blood collection

Background

Serum and plasma are used for measurements of microRNAs (miRNAs) as biomarkers of various diseases. However, no consistent findings have been obtained regarding differences in serum and plasma levels of miRNAs. The purpose of this study was to clarify differences in serum and plasma levels of total miRNAs and their time-course changes after blood collection.

Methods

Venous blood was collected from healthy men, and samples were prepared at the time points of 0, 15, 30, 60 and 180 min after blood collection for plasma and after clot formation for serum. Levels of total miRNAs were analyzed by the hybridization method using the 3D-Gene miRNA Oligo chip.

Results

About one third of 2632 miRNAs tested showed levels high enough for comparison of serum and plasma levels and for investigation of their time-course changes. Levels of 299 miRNAs at time 0 were significantly different in serum and plasma. Levels of representative platelet-derived miRNAs including miR-185-5p, -22-3p and -320b were significantly higher in plasma than in serum, while levels of representative erythrocyte-derived miRNAs including miR-451a, -486-5p and -92a-3p were not significantly different in serum and plasma. Plasma levels of 173 miRNAs and 6 miRNAs showed significant decreasing and increasing tendencies, respectively, while there were no miRNAs in serum that showed significant time-course changes.

Conclusion

The results suggest that careful attention should be paid when comparing serum and plasma levels of miRNAs and that plasma samples should be prepared early after blood collection.

Is post-hypertonic lysis of human red blood cells caused by excessive cell volume regulation?

Human red blood cells (RBC) exposed to hypertonic media are subject to post-hypertonic lysis - an injury that only develops during resuspension to an isotonic medium. The nature of post-hypertonic lysis was previously hypothesized to be osmotic when cation leaks were observed, and salt loading was suggested as a cause of the cell swelling upon resuspension in an isotonic medium. However, it was problematic to account for the salt loading since the plasma membrane of human RBCs was considered impermeable to cations. In this study, the hypertonicity-related behavior of human RBCs is revisited within the framework of modern cell physiology, considering current knowledge on membrane ion transport mechanisms - an account still missing. It is recognized here that the hypertonic behavior of human RBCs is consistent with the acute regulatory volume increase (RVI) response - a healthy physiological reaction initiated by cells to regulate their volume by salt accumulation. It is shown by reviewing the published studies that human RBCs can increase cation conductance considerably by activating cell volume-regulated ion transport pathways inactive under normal isotonic conditions and thus facilitate salt loading. A simplified physiological model accounting for transmembrane ion fluxes and membrane voltage predicts the isotonic cell swelling associated with increased cation conductance, eventually reaching hemolytic volume. The proposed involvement of cell volume regulation mechanisms shows the potential to explain the complex nature of the osmotic response of human RBCs and other cells. Cryobiological implications, including mechanisms of cryoprotection, are discussed.

Plasmodium falciparum glutamic acid-rich protein (PfGARP)-independent polyclonal antibodies inhibit malaria parasite growth in human erythrocytes

PfGARP is a recently characterized cell surface antigen encoded by Plasmodium falciparum, the causative agent of severe human malaria pathophysiology. Previously, we reported that the human erythrocyte band 3 (SLC4A1) serves as a host receptor for PfGARP. Antibodies against PfGARP did not affect parasite invasion and growth. We surmised that PfGARP may play a role in the rosetting and adhesion of malaria. Another study reported that antibodies targeting PfGARP exhibit potent inhibition of parasite growth. This inhibition occurred without the presence of any immune or complement components, suggesting the activation of an inherent density-dependent regulatory system. Here, we used polyclonal antibodies against PfGARP and a monoclonal antibody mAb78993 to demonstrate that anti-PfGARP polyclonal antibodies, but not mAb7899, exerted potent inhibition of parasite growth in infected erythrocytes independent of PfGARP. These findings suggest that an unknown malaria protein(s) is the target of growth arrest by polyclonal antibodies raised against PfGARP.

Investigation of the cytotoxicity, genotoxicity and antioxidant prospects of JM-20 on human blood cells: A multi-target compound with potential therapeutic applications

JM-20 is a 1,5-benzodiazepine compound fused to a dihydropyridine fraction with different pharmacological properties. However, its potential toxic effects on blood cells have not yet been reported. Thus, the present study aimed to investigate, for the first time, the possible cytotoxicity of JM-20 through cell viability, cell cycle, morphology changes, reactive species (RS) to DCFH-DA, and lipid peroxidation in human leukocytes, its hemolytic effect on human erythrocytes, and its potential DNA genotoxicity using plasmid DNA in vitro. Furthermore, the compound's ability to reduce the DPPH radical was also measured. Human blood was obtained from healthy volunteers (30 ± 10 years old), and the leukocytes or erythrocytes were immediately isolated and treated with different concentrations of JM-20. A cytoprotective effect was exhibited by 10 μM JM-20 against 1 mM tert-butyl hydroperoxide (t-but-OOH) in the leukocytes. However, the highest tested concentrations of the compound (20 and 50 μM) changed the morphology and caused a significant decrease in the cell viability of leukocytes (p < 0.05, in comparison with Control). All tested concentrations of JM-20 also resulted in a significant increase in intracellular RS as measured by DCFH-DA in these cells (p < 0.05, in comparison with Control). On the other hand, the results point out a potent antioxidant effect of JM-20, which was similar to the classical antioxidant α-tocopherol. The IC50 value of JM-20 against the lipid peroxidation induced by (FeII) was 1.051 μM ± 0.21, while the IC50 value of α-tocopherol in this parameter was 1.065 μM ± 0.34. Additionally, 50 and 100 μM JM-20 reduced the DPPH radical in a statistically similar way to the 100 μM α-tocopherol (p < 0.05, in comparison with the control). No significant hemolysis in erythrocytes, no cell cycle changes in leukocytes, and no genotoxic effects in plasmid DNA were induced by JM-20 at any tested concentration. The in silico pharmacokinetic and toxicological properties of JM-20, derivatives, and nifedipine were also studied. Here, our findings demonstrate that JM-20 and its putative metabolites exhibit similar characteristics to nifedipine, and the in vitro and in silico data support the low toxicity of JM-20 to mammals.

Multielement analysis of single red blood cells by single cell - inductively coupled plasma tandem mass spectrometry

A method for the analysis of essential metals (Fe, Cu, Mg, and Zn) and non-metals (P, S) in single red blood cells was developed by single cell (SC)-ICP-MS. The use of a triple quadrupole configuration (MS/MS) enabled an effective elimination of polyatomic interferences, which affect the accuracy of ICP-MS analysis using a single quadrupole mass analyzer. Fixation with glutaraldehyde for at least 90 days was developed to improve the quantification of elements in a single red blood cell. The experimental conditions were optimized while special attention was paid to the residence time of analytes in the plasma. Addition of a surfactant (0.05% (v/v) Tween80®) improved quantification of elements in fixed red blood cells. The detection limits obtained by SC-ICP-MS/MS were lower than for ICP-MS, especially for S and P (3 fg and 1.7 fg. cell-1 instead of 163 and 6.3 fg. cell-1, respectively).

Association of initial lactate levels and red blood cell transfusion strategy with outcomes after severe trauma: a post hoc analysis of the RESTRIC trial

BACKGROUND

The appropriateness of a restrictive transfusion strategy for those with active bleeding after traumatic injury remains uncertain. Given the association between tissue hypoxia and lactate levels, we hypothesized that the optimal transfusion strategy may differ based on lactate levels. This post hoc analysis of the RESTRIC trial sought to investigate the association between transfusion strategies and patient outcomes based on initial lactate levels.

METHODS

We performed a post hoc analysis of the RESTRIC trial, a cluster-randomized, crossover, non-inferiority multicenter trials, comparing a restrictive and liberal red blood cell transfusion strategy for adult trauma patients at risk of major bleeding. This was conducted during the initial phase of trauma resuscitation; from emergency department arrival up to 7 days after hospital admission or intensive care unit (ICU) discharge. Patients were grouped by lactate levels at emergency department arrival: low (< 2.5 mmol/L), middle (≥ 2.5 and < 4.0 mmol/L), and high (≥ 4.0 mmol/L). We compared 28 days mortality and ICU-free and ventilator-free days using multiple linear regression among groups.

RESULTS

Of the 422 RESTRIC trial participants, 396 were analyzed, with low (n = 131), middle (n = 113), and high (n = 152) lactate. Across all lactate groups, 28 days mortality was similar between strategies. However, in the low lactate group, the restrictive approach correlated with more ICU-free (β coefficient 3.16; 95% CI 0.45 to 5.86) and ventilator-free days (β coefficient 2.72; 95% CI 0.18 to 5.26) compared to the liberal strategy. These findings persisted even after excluding patients with severe traumatic brain injury.

CONCLUSIONS

Our results suggest that restrictive transfusion strategy might not have a significant impact on 28-day survival rates, regardless of lactate levels. However, the liberal transfusion strategy may lead to shorter ICU- and ventilator-free days for patients with low initial blood lactate levels.

Erythrocyte-based Drug Delivery: How Far from Clinical Application?

Erythrocytes are responsible for delivering oxygen throughout the body. They have become suitable drug carriers due to outstanding advantages, such as a long lifespan in circulation, high biosafety, and low immunogenicity. Although erythrocyte-based drug delivery has good application prospects and has become a research hotspot in related fields, the application of erythrocyte-based drug delivery systems is rare in the clinic now. In this review, we discuss the characteristics of erythrocytes, diverse drug-loading approaches, and research progress of erythrocyte-based drug delivery systems. Finally, we explore the challenges of erythrocyte-based drug delivery in clinical application.

Isolation and functional identification of immune cells in hemolymph of blood clams Tegillarca granosa

Blood clam Tegillarca granosa is a type of economically cultivated bivalve mollusk with red blood, and it primarily relies on hemocytes in its hemolymph for immune defense. However, there are currently no reports on the isolation and identification of immune cells in T. granosa, which hinders our understanding of their immune defense. In this study, we employed single-cell transcriptome sequencing (scRNA-seq) to visualize the molecular profile of hemocytes in T. granosa. Based on differential expression of immune genes and hemoglobin genes, hemocytes can be molecularly classified into immune cells and erythrocytes. In addition, we separated immune cells using density gradient centrifugation and demonstrated their stronger phagocytic capacity compared to erythrocytes, as well as higher levels of ROS and NO. In summary, our experiments involved the isolation and functional identification of immune cells in hemolymph of T. granosa. This study will provide valuable insights into the innate immune system of red-blood mollusks and further deepen the immunological research of mollusks.

Haematological reference intervals for pregnant Icelandic mares on pasture

BACKGROUND

Few studies have been conducted on haematological reference intervals (RIs) in Icelandic horses. Reference intervals have been published for Icelandic horses in Austria and a preliminary study in Iceland compared haematological values in riding horses to published RIs for other breeds as well as Icelandic horses abroad. Haematological parameters can vary greatly due to factors such as breed, gender, age, reproductive status, and training, as well as feeding, prior exercise and management method. Icelandic broodmares are kept on pasture under supervision throughout the year, with haylage provided during the winter, and it is therefore of interest to establish haematological reference intervals for pregnant broodmares in Iceland. The purpose of this study was to establish haematological RIs specific to Icelandic broodmares in the first months of pregnancy, kept on pasture. Blood samples from 183 mares, stabilised in EDTA were analysed using IDEXX ProCyte Dx and total protein was analysed in serum samples from 157 of the 183 mares, using IDEXX Catalyst One analyser. The RIs were established using the guidelines of the American Society for Veterinary Clinical Pathology.

RESULTS

The RIs for red blood cell count, haematocrit and haemoglobin were higher in pasture-kept Icelandic mares in early pregnancy, most of which were lactating, than in pregnant mares of other breeds. This was also true for white blood cell count, as well as numbers of monocytes, eosinophils, and basophils, which in some instances might illustrate problems in the automated categorisation of some leukocytes.

CONCLUSIONS

As no RIs have been published for other pasture-kept Icelandic horses, future investigations should include other groups of pasture-kept Icelandic horses. Such an analysis might elucidate the effect of breed, management, and pregnancy on haematological values in pasture-kept Icelandic horses.

Cytotoxicity and immunological impact of Trypanosoma sp. infection on blood parameters of wild African catfish, Clarias gariepinus

Fish trypanosomiasis is a common blood parasitic disease transmitted by aquatic invertebrates, such as leeches. This study aims to shed light on the cytotoxicity of Trypanosoma sp. on erythrocytes and its impacts on the innate immune response (serum lysozyme activity, nitric oxide production, phagocytic activity, serum total protein, and globulin) in wild African catfish, Clarias gariepinus. One hundred catfish were examined using blood smears stained with Giemsa and confirmed with PCR. The prevalence of infection was found to be 10% by microscope detection and 15% by PCR. The morphological identification of Trypanosoma as Trypanosoma mukasai was determined. Additionally, this study included previously undescribed features of Trypanosoma, such as the width of the anterior and posterior body, the length of the posterior pale region, and the number of folds. Various alterations in erythrocytes were observed, totaling 54.57%. Nuclear abnormalities, including fragmented nuclei, eccentric nuclei, and micronuclei, were also reported. Infected fish showed a reduction in serum total protein and globulin levels, while nitric oxide production, lysozyme activity, and phagocytic activity exhibited a significant increase compared to non-infected fish. We believe that our findings will contribute valuable data to the morphological and molecular identification of Trypanosoma sp. in African catfish, as well as their cytotoxic impact.

Nickel chloride generates cytotoxic ROS that cause oxidative damage in human erythrocytes

BACKGROUND

Nickel is a heavy metal that is regarded as a possible hazard to living organisms due to its toxicity and carcinogenicity. Nickel chloride (NiCl2), an inorganic divalent Ni compound, has been shown to cause oxidative stress in cells by altering the redox equilibrium. We have investigated the effect of NiCl2 on isolated human erythrocytes under in vitro condition.

METHODS

Isolated erythrocytes were treated with different concentrations of NiCl2 (25-500 µM) for 24 h at 37 ºC. Hemolysates were prepared and several biochemical parameters were analyzed in them.

RESULTS

Treatment of erythrocytes with NiCl2 enhanced the intracellular generation of reactive oxygen species (ROS). A significant increase in hydrogen peroxide levels and oxidation of proteins and lipids was also seen. This was accompanied by a reduction in levels of nitric oxide, glutathione, free amino groups and total sulfhydryl groups. NiCl2 treatment impaired both enzymatic and non-enzymatic defense systems, resulting in lowered antioxidant capacity and diminished ability of cells to quench free radicals and reduce metal ions. NiCl2 exposure also had an inhibitory effect on the activity of enzymes involved in pathways of glucose metabolism (glycolytic and pentose phosphate shunt pathways). Increased level of methemoglobin, which is inactive in oxygen transport, was also seen. The rate of heme breakdown increased resulting in the release of free iron. Exposure to NiCl2 led to considerable cell lysis, indicating damage to the erythrocyte membrane. This was supported by the inhibition of membrane bound enzymes and increase in the osmotic fragility of NiCl2 treated cells. NiCl2 treatment caused severe morphological alterations with the conversion of normal discocytes to echinocytes. All changes were seen in a NiCl2 concentration-dependent manner.

CONCLUSION

NiCl2 generates cytotoxic ROS in human erythrocytes which cause oxidative damage that can decrease the oxygen carrying capacity of blood and also lead to anemia.

Evaluation of the Genotoxic and Histological Effects in Neotropical Fish Prochilodus Lacustris (Pisces, Prochilodontidae) in Conservation Area of the Brazilian Northeast

Human activities significantly impact the aquatic biota in lacustrine environments, leading to negative environmental consequences. Due to this, this study was carried out to evaluate the genotoxic and histological biomarkers in the gills and kidneys of Prochilodus lacustris. The collection of fish and water was conducted in three distinct stations (S1, S2, S3) in an international protected area in northeast Brazil. The histological alterations index was used to assess changes in the gills and kidneys at a histological level. In addition, micronucleus and nuclear abnormalities tests were employed to examine damage to the genetic material. According to the frequency of Micronucleus, nuclear injuries, and the histopathology of gills and kidneys, it can be inferred that station S1 had the highest impact on the fish, causing significant harm. Based on our findings, the organisms residing in Lake Açu are adversely affected by the poor environmental conditions. This raises doubts about the effectiveness of the Protection Area by Humid Zone of International Interest in Northeast Brazil.

Acquired elliptocytosis in chronic myeloid neoplasms: An enigmatic relationship to acquired red cell membrane protein and genetic abnormalities

Nineteen reports of 41 cases of acquired red cell elliptocytosis associated with a chronic myeloid neoplasm are described. Although the majority of cases have an abnormality of the long arm of chromosome 20, del(q20), several cases do not. Moreover, in one case a specific qualitative abnormality of red cell protein band 4.1(4.1R) was reported; however, several subsequent cases could find no abnormality of a red cell membrane protein or found a different abnormality, usually quantitative. Thus, this striking red cell phenotypic feature, acquired elliptocytosis, seen in myelodysplastic syndrome and other chronic myeloproliferative diseases, closely simulating the red cell phenotype of hereditary elliptocytosis, has an unexplained genetic basis, presumably as the result of an acquired mutation(s) in some chronic myeloid neoplasms.

Evidence that fish death after Vibrio vulnificus infection is due to an acute inflammatory response triggered by a toxin of the MARTX family

Vibrio vulnificus is an emerging zoonotic pathogen associated with fish farms that is capable of causing a hemorrhagic septicemia known as warm-water vibriosis. According to a recent transcriptomic and functional study, the death of fish due to vibriosis is more related to the inflammatory response of the host than to the tissue lesions caused by the pathogen. In this work, we hypothesize that the RtxA1 toxin (a V. vulnificus toxin of the MARTX (Multifunctional Autoprocessing Repeats in Toxin) family) is the key virulence factor that would directly or indirectly trigger this fatal inflammatory response. Our hypothesis was based on previous studies that showed that rtxA1-deficient mutants maintained their ability to colonize and invade, but were unable to kill fish. To demonstrate this hypothesis, we infected eels (model of fish vibriosis) by immersion with a mutant deficient in RtxA1 production and analyzed their transcriptome in blood, red blood cells and white blood cells during early vibriosis (0, 3 and 12 h post-infection). The transcriptomic results were compared with those obtained in the previous study in which eels were infected with the V. vulnificus parental strain, and were functionally validated. Overall, our results confirm that fish death after V. vulnificus infection is due to an acute, early and atypical inflammatory response triggered by RtxA1 in which red blood cells seem to play a central role. These results could be relevant to other vibriosis as the toxins of this family are widespread in the Vibrio genus.

Antimicrobial, anti-inflammatory and anti-arthritic activity of hemolymph lectin (NagLec) isolated from the freshwater crab, Oziotelphusanaga

Lectins are non-immune glycoproteins or proteins having a unique capacity to interact with carbohydrate ligands found on the surface of their host cells. In the present investigation, the lectin was purified from the hemolymph of freshwater crab, Oziotelphusa naga and its antimicrobial, anti-inflammatory and anti-arthritic activity was analysed. The preliminary characterization of the hemagglutinin was carried out to identify the erythrocyte and sugar specificity, optimum pH and temperature and cation dependency. The agglutinin was found to be highly specific to rabbit erythrocyte and inhibited by fetuin and α-lactose. Maximum hemagglutination activity was noted at pH 7.5-8 and temperature 20-40 °C. An O-acetyl sialic acid specific 75 kDa hemolymph lectin, designated as NagLec was isolated from the freshwater crab, Oziotelphusa naga by affinity chromatography on fetuin coupled Sepharose 4 B, with a purification fold of 185. The bacteria Staphylococcus aureus, Proteus mirabilis and fungus Candida albicans had the greatest zone of inhibition when treated with NagLec. The results of the Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) assays showed that the purified lectin inhibited the growth of Staphylococcus aureus at 0.031 and 0.065 μg/ml, which proved the bactericidal property of NagLec. NagLec generated alterations on the bacterial cells and led to protein leakage, which was dosage (24 and 48 μg/ml) and time dependent (10-40 min). COX and LOX enzyme was inhibited to 49.43% and 61.81% with 100 μg/ml concentration of NagLec respectively, demonstrating NagLec's ability to reduce inflammation. Furthermore, NagLec (500 μg) suppressed protein denaturation up to 77.12% whereas diclofenac sodium (a standard drug) was inhibited by 89.36%. The results indicate that NagLec, a sialic acid specific lectin isolated from the freshwater crab O. naga could be formulated as a nano drug in future owing to its antimicrobial, anti-inflammatory and anti-arthritic potential that could be targeted to specific pathogenic microbes and treat arthritis.

A novel mini-invasive finger-prick protocol for preparing blood micro-samples for morphological analysis of human erythrocytes by scanning electron microscopy

Here we describe the development and optimization of a new protocol for the preparation and surface imaging by scanning electron microscope of human erythrocytes from blood micro-samples obtained by finger prick. By testing several key pre-analytical conditions for blood sampling, erythrocyte preservation, storage and imaging, we designed a rapid new minimally-invasive reproducible method for obtaining uniform deposition of an adequate number of erythrocytes with well-preserved morphology on a substrate. The possibility of obtaining reliable reproducible high resolution morphometric data on peripheral erythrocytes makes this protocol valuable for diagnostic and basic research purposes.

Larger splenic emptying correlate with slower EPOC kinetics in healthy men and women during supine cycling

PURPOSE

The present study investigated whether larger splenic emptying augments faster excess post-exercise O2 consumption (EPOC) following aerobic exercise cessation.

METHODS

Fifteen healthy participants (age 24 ± 4, 47% women) completed 3 laboratory visits at least 48-h apart. After obtaining medical clearance and familiarizing themselves with the test, they performed a ramp-incremental test in the supine position until task failure. At their final visit, they completed three step-transition tests from 20 W to a moderate-intensity power output (PO), equivalent to [Formula: see text]O2 at 90% gas exchange threshold, where data on metabolic, cardiovascular, and splenic responses were recorded simultaneously. After step-transition test cessation, EPOCfast was recorded, and the first 10 min of the recovery period was used for further analysis. Blood samples were collected before and immediately after the end of exercise.

RESULTS

In response to moderate-intensity supine cycling ([Formula: see text]O2 = ~ 2.1 L·min-1), a decrease in spleen volume of ~ 35% (p = 0.001) was observed, resulting in a transient increase in red cell count of ~ 3-4% (p = 0.001) in mixed venous blood. In parallel, mean blood pressure, heart rate, and stroke volume increased by 30-100%, respectively. During recovery, mean τ[Formula: see text]O2 was 45 ± 18 s, the amplitude was 2.4 ± 0.5 L·min-1, and EPOCfast was 1.69 L·O2. Significant correlations were observed between the percent change in spleen volume and (i) EPOCfast (r = - 0.657, p = 0.008) and (ii) τ[Formula: see text]O2 (r = - 0.619, p = 0.008), but not between the change in spleen volume and (iii) [Formula: see text]O2 peak (r = 0.435, p = 0.105).

CONCLUSION

Apparently, during supine cycling, individuals with larger spleen emptying tend to have slower [Formula: see text] O2 recovery kinetics and a greater EPOCfast.

An erythrocyte-centric view on the MFSD2B sphingosine-1-phosphate transporter

MFSD2B has been identified as the exclusive sphingosine-1-phosphate (S1P) transporter in red blood cells (RBC) and platelets. MFSD2B-mediated S1P export from platelets is required for aggregation and thrombus formation, whereas RBC MFSD2B maintains plasma S1P levels in concert with SPNS2, the vascular and lymphatic endothelial cell S1P exporter, to control endothelial permeability and ensure normal vascular development. However, the physiological function of MFSD2B in RBC remains rather elusive despite mounting evidence that the intracellular S1P pool plays important roles in RBC glycolysis, adaptation to hypoxia and the regulation of cell shape, hydration, and cytoskeletal organisation. The large accumulation of S1P and sphingosine in MFSD2B-deficient RBC coincides with stomatocytosis and membrane abnormalities, the reasons for which have remained obscure. MFS family members transport substrates in a cation-dependent manner along electrochemical gradients, and disturbances in cation permeability are known to alter cell hydration and shape in RBC. Furthermore, the mfsd2 gene is a transcriptional target of GATA together with mylk3, the gene encoding myosin light chain kinase (MYLK). S1P is known to activate MYLK and thereby impact on myosin phosphorylation and cytoskeletal architecture. This suggests that metabolic, transcriptional and functional interactions may exist between MFSD2B-mediated S1P transport and RBC deformability. Here, we review the evidence for such interactions and the implications for RBC homeostasis.

Effect of a pescetarian and vegan diet on fatty acid composition in blood and spermatozoa in young healthy men

INTRODUCTION

There is a growing interest in vegetarian and vegan diets, but both can potentially affect tissue fatty acids (FA) composition. We aimed to evaluate the effect of vegetarian diets on plasma, erythrocytes, and sperm n-3 polyunsaturated fatty acids (n-3 PUFA) status in healthy young men.

METHODS

Four groups were studied: i) men consuming a regular omnivore diet (OMV-1, n = 35); ii) men consuming an omnivore diet but excluding fish and seafood (OMV-2, n = 34); iii) men consuming a pescetarian diet (including dairy, eggs, fish, and seafood) (PESC, n = 36); and iv) men following a strict vegan diet (VEG, n = 35). Participants in each group should follow their diet for at least the previous 12 months. Diet evaluation used a structured validated food frequency questionnaire. FA composition was measured in plasma, erythrocyte phospho-lipids, and spermatozoa by gas-liquid chromatography, expressed as a mole percentage of the total FA content.

RESULTS

Main findings showed higher alpha-linolenic fatty acid (ALA) and total n-3 PUFA dietary intake in the VEG group. In plasma, arachidonic and eicosapentaenoic acids were higher in OMV and PESC groups, whereas docosahexaenoic acid (DHA) level was lower in VEG. Higher ALA, but reduced DHA and total n-3 PUFA levels were found in erythrocytes and spermatozoa in the VEG group.

CONCLUSION

Higher dietary ALA intake was found in pescetarians and vegan men. However, the higher ALA intake was not reflected in higher DHA content in the evaluated tissues. PUFA assessment, with particular emphasis in DHA, are necessary to improve PUFA status in vegan men.

Vanillin attenuates CdCl2-induced cytotoxicity in isolated human erythrocytes

Cadmium is a toxic heavy metal with no physiological role in the human body. Cadmium has high mobility due to its widespread industrial use, with no safe and effective therapeutic management. Cadmium toxicity manifests by increasing oxidative stress in target cells. We have explored the potential role of vanillin, a plant phenolic aldehyde and antioxidant, in mitigating cadmium chloride (CdCl2) induced hemotoxicity using isolated human erythrocytes. CdCl2 was added to erythrocytes, in the absence and presence of vanillin. Incubation of erythrocytes with CdCl2 alone inhibited methemoglobin reductase and enhanced methemoglobin level. Heme degradation and release of free iron (Fe2+), along with protein and membrane lipid oxidation, were also increased. A CdCl2-induced enhancement in reactive oxygen and nitrogen species was also seen, lowering the overall antioxidant power of cells. However, pre-incubation of erythrocytes with vanillin resulted in significant decreased generation of reactive species and prevented heme degradation and heme oxidation. Vanillin augmented the erythrocyte antioxidant capacity and reinstated the activities of major antioxidant, plasma membrane-bound and glucose metabolism enzymes. Scanning electron microscopy showed that CdCl2 treatment led to the formation of echinocytes which was prevented by vanillin. In all cases, no harmful effects of vanillin alone were seen. Thus, vanillin alleviates the toxicity of cadmium and can be potentially employed as a chemoprotectant against the damaging effects of this heavy metal.

Development of an LC-MS/MS assay with automated sample preparation for phosphatidylethanol (PEth)- Not your typical clinical marker

Phosphatidylethanol (PEth) is a group of phospholipids formed exclusively in the presence of ethanol on the erythrocyte membrane, making it a direct biomarker for long-term ethanol consumption for which a clinical reference interval has been established. Here, we describe an assay for quantitation for two most abundant PEth homologues, PEth 16:0/18:1 and PEth 16:0/18:2, from human whole blood, and present challenges overcome throughout the development process. Since PEth is localized within erythrocyte membranes, a reliable sample preparation technique is an important aspect of PEth analysis. Therefore, various erythrocyte lysing agents for recovery of exogenously spiked standards and controls were evaluated to identify one that performed comparably to the recovery of endogenous analytes found in authentic samples. A supported liquid extraction (SLE) technique was employed for sample cleanup and enrichment which together with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis enabled automated sample preparation, appropriate chromatographic resolution, and minimal system carryover. This resulted in a laboratory developed test with an analytical measurement range (AMR) of 10-1000 ng/mL (slope = 0.9902-1.0138, R2 = 0.9958-0.9972), that was precise (intra-day precision: 3.4-4.1%; inter-day precision: 4.4-8.2% over the AMR), accurate when compared with an available external laboratory test (slope = 0.9943-1.0206, R2 = 0.9635-0.9678, no lower decision point interpretation changes), with effective analyte recovery (77.2-83.5%), and established stability characteristics, while chromatographically separating the analytes to ensure no additive effects due to the isotopic distribution of the opposing analyte.

Accumulation of oxysterols in the erythrocytes of COVID-19 patients as a biomarker for case severity

BACKGROUND

Due to the high risk of COVID-19 patients developing thrombosis in the circulating blood, atherosclerosis, and myocardial infarction, it is necessary to study the lipidome of erythrocytes. Specifically, we examined the pathogenic oxysterols and acylcarnitines in the erythrocyte homogenate of COVID-19 patients. These molecules can damage cells and contribute to the development of these diseases.

METHODS

This study included 30 patients and 30 healthy volunteers. The erythrocyte homogenate extract was analyzed using linear ion trap mass spectrometry combined with high-performance liquid chromatography. The concentrations of oxysterols and acylcarnitines in erythrocyte homogenates of healthy individuals and COVID-19 patients were measured. Elevated levels of toxic biomarkers in red blood cells could initiate oxidative stress, leading to a process known as Eryptosis.

RESULTS

In COVID-19 patients, the levels of five oxysterols and six acylcarnitines in erythrocyte homogenates were significantly higher than those in healthy individuals, with a p-value of less than 0.05. The mean total concentration of oxysterols in the red blood cells of COVID-19 patients was 23.36 ± 13.47 μg/mL, while in healthy volunteers, the mean total concentration was 4.92 ± 1.61 μg/mL. The 7-ketocholesterol and 4-cholestenone levels were five and ten times higher, respectively, in COVID-19 patients than in healthy individuals. The concentration of acylcarnitines in the red blood cell homogenate of COVID-19 patients was 2 to 4 times higher than that of healthy volunteers on average. This finding suggests that these toxic biomarkers may cause the red blood cell death seen in COVID-19 patients.

CONCLUSIONS

The abnormally high levels of oxysterols and acylcarnitines found in the erythrocytes of COVID-19 patients were associated with the severity of the cases, complications, and the substantial risk of thrombosis. The concentration of oxysterols in the erythrocyte homogenate could serve as a diagnostic biomarker for COVID-19 case severity.

Associations of obesity and body shape with erythrocyte and reticulocyte parameters in the UK Biobank cohort

BACKGROUND

Obesity is associated with type 2 diabetes mellitus and chronic low-grade inflammation. Although chronic inflammatory conditions and diabetes are associated with anaemia, less is known about associations of obesity and body shape, independent of each other, with erythrocyte and reticulocyte parameters.

METHODS

We investigated the associations of body mass index (BMI) and the allometric body shape index (ABSI) and hip index (HI), which are uncorrelated with BMI, with erythrocyte and reticulocyte parameters (all continuous, on a standard deviation (SD) scale) in UK Biobank participants without known metabolic, endocrine, or major inflammatory conditions (glycated haemoglobin HbA1c < 48 mmol/mol, C-reactive protein CRP < 10 mg/L). We examined erythrocyte count, total reticulocyte count and percent, immature reticulocyte count and fraction (IRF), haemoglobin, haematocrit, mean corpuscular haemoglobin mass (MCH) and concentration (MCHC), mean corpuscular and reticulocyte volumes (MCV, MRV), and red cell distribution width (RDW) in multivariable linear regression models. We additionally defined body shape phenotypes with dichotomised ABSI (≥ 73 women; ≥ 80 men) and HI (≥ 64 women; ≥ 49 men), including "pear" (small-ABSI-large-HI) and "apple" (large-ABSI-small-HI), and examined these in groups according to BMI (18.5-25 normal weight; 25-30 overweight; 30-45 kg/m² obese).

RESULTS

In 105,853 women and 100,854 men, BMI and ABSI were associated positively with haemoglobin, haematocrit, and erythrocyte count, and more strongly with total reticulocyte count and percent, immature reticulocyte count and IRF. HI was associated inversely with all, but least with IRF. Associations were comparable in women and men. In groups according to obesity and body shape, erythrocyte count was ~ 0.6 SD higher for obese-"apple" compared to normal-weight-"pear" phenotype (SD = 0.31*10¹²/L women, SD = 0.34*10¹²/L men), total reticulocyte count was ~ 1.1 SD higher (SD = 21.1*10⁹/L women, SD = 23.6*10⁹/L men), immature reticulocyte count was ~ 1.2 SD higher (SD = 7.9*10⁹/L women, SD = 8.8*10⁹/L men), total reticulocyte percent was ~ 1.0 SD higher (SD = 0.48% women and men), and IFR was over 0.7 SD higher (SD = 5.7% women and men). BMI but not ABSI or HI was associated more weakly inversely with MCV, MRV, and MCH, but positively with MCHC in men and RDW in women.

CONCLUSIONS

In obesity uncomplicated with diabetes, larger BMI and ABSI are associated with increased erythropoiesis and reticulocyte immaturity.

Micronuclei and nuclear buds in amniotic tissue of rats treated with cyclophosphamide

Fetal development can be altered by DNA damage caused by maternal exposure to chemical, physical, or biological agents during gestation. One method of assessing genotoxicity is to detect micronuclei (MNs) and/or nuclear abnormalities. This can be performed in vivo and requires only frequently dividing tissues, such as amniotic tissue (AT), which is in contact with the fetal environment and is composed of very thin layers of cells. This study evaluated the presence of MNs, nucleoplasmic bridges, and nuclear buds (NBs) in the fetal AT following maternal exposure to cyclophosphamide (CP) during pregnancy. Pregnant Wistar rats were divided into a negative control group and an experimental group that was orally administered CP (10 mg/kg). Daily blood smears were obtained from pregnant rats on days 14-19 of gestation. The rats were dissected, and fetal ATs were obtained on the 19th day of gestation. The MN and NB frequencies in AT cells were analyzed using a fluorescence microscope (100 ×). Micronucleated erythrocytes in the peripheral blood of the control rats were also assessed. Micronucleated polychromatic erythrocyte frequencies were significantly higher than those in the controls. Polychromatic erythrocyte frequencies were lower in CP-treated rats than in controls at 48-120 h. Fetuses in the CP-treated group also showed a significant increase in MNs and NBs in AT cells. In conclusion, AT could be used for analyzing MNs and NBs in rats following maternal exposure to a genotoxic agent and as a viable alternative for analyzing the integrity of fetal DNA during gestation.

Prevalence Rate of Thalassemia Carriers among Individuals with Microcytosis or Hypochromia in Portugal

INTRODUCTION

Microcytosis and hypochromia result from deficient hemoglobin synthesis in red blood cells and are easily detected in a complete blood count test. These conditions are mainly due to iron nutritional deficiency, but may also result from some genetic diseases, such as thalassemia. The aim of this study was to determine the contribution of β- and α-thalassemia to these abnormal hematological phenotypes in a representative sample of adult individuals living in Portugal who participated in the first Portuguese National Health Examination Survey (INSEF).

MATERIAL AND METHODS

Among the 4808 INSEF participants, 204 had microcytosis, hypochromia or both. The corresponding 204 DNAs were screened for changes in the β-globin gene by next-generation sequencing and Sanger sequencing. In addition, α-thalassemia deletions within the α-globin cluster were investigated by Gap-PCR and multiplex ligation-dependent probe amplification.

RESULTS

In this selected subgroup of INSEF participants, 54 had α-thalassemia (26%), predominantly caused by the -α3.7kb deletion, and 22 were β-thalassemia carriers (11%) mainly due to point mutations in the β-globin gene previously known in Portugal.

CONCLUSION

Thalassemia trait is a frequent cause of microcytosis or hypochromia in Portugal since this genetic condition was found in 37% of the investigated cases.

Interactions of ultrashort laser pulses with hemoglobin: Photophysical aspects and potential applications

Hemoglobin (Hb), a life-sustaining and highly abundant erythrocyte protein, is not readily fluorescent. A few studies have already reported Two-Photon Excited Fluorescence (TPEF) of Hb, however, the mechanisms through which Hb becomes fluorescent upon interaction with ultrashort laser pulses are not completely understood. Here, we characterized photophysically this interaction on Hb thin film and erythrocytes using fluorescence spectroscopy upon single-photon/two-photon absorption, and UV-VIS single-photon absorption spectroscopy. A gradual increase of the fluorescence intensity, ending up with saturation, is observed upon prolonged exposure of Hb thin layer and erythrocytes to ultrashort laser pulses at 730 nm. When compared to protoporphyrin IX (PpIX) and oxidized Hb by H₂O₂, TPEF spectra from a thin Hb film and erythrocytes showed good mutual agreement, broad peaking at 550 nm, supporting hemoglobin undergoes degradation and that same fluorescent specie(s) originating from the heme moiety are generated. The uniform square shaped patterns of the fluorescent photoproduct exhibited the same level of the fluorescence intensity even after 12 weeks from the formation, indicating high photoproduct stability. We finally demonstrated the full potential of the formed Hb photoproduct with TPEF scanning microscopy towards spatiotemporally controlled micropatterning in HTF and single human erythrocyte labelling and tracking in the whole blood.

Mercury Exposure in Birds of Prey from Norway: Relation to Stable Carbon and Nitrogen Isotope Signatures in Body Feathers

Mercury (Hg) and stable carbon and nitrogen isotope ratios were analysed in body feathers from nestlings of white-tailed eagles (Haliaeetus albicilla) (WTE; n = 13) and Northern goshawks (Accipiter gentilis) (NG; n = 8) and in red blood cells (RBC) from NG (n = 11) from Norway. According to linear mixed model, species factor was significant in explaining the Hg concentration in feathers (LMM; p < 0.001, estimate (WTE) = 2.51, 95% CI = 1.26, 3.76), with concentrations higher in WTE (3.01 ± 1.34 µg g^-1 dry weight) than in NG (0.51 ± 0.34 µg g^-1 dry weight). This difference and the isotopic patterns for each species, likely reflect their diet, as WTE predominantly feed on a marine and higher trophic-chain diet compared to the terrestrial NG. In addition, Hg concentrations in RBCs of NG nestlings were positively correlated with feather Hg concentrations (Rho = 0.77, p = 0.03), supporting the potential usefulness of nestling body feathers to biomonitor and estimate Hg exposure. Hg levels in both species were generally below the commonly applied toxicity threshold of 5 µg g^-1 in feathers, although exceeded in two WTE (6.08 and 5.19 µg g^-1 dry weight).

Assessing the Cytotoxicity of TiO2-x Nanoparticles with a Different Ti3+(Ti2+)/Ti4+ Ratio

Titanium dioxide (TiO₂) nanoparticles are promising biomedical agents characterized by good biocompatibility. In this study, we explored the cytotoxicity of TiO_2-x nanoparticles with a different Ti³⁺(Ti²⁺)/Ti⁴⁺ ratio and analyzed the efficiency of eryptosis indices as a tool in nanotoxicology. Two types of TiO_2-x nanoparticles (NPs) were synthesized by the hydrolysis of titanium alkoxide varying the nitric acid content in the hydrolysis mixture. Transmission electron microscopy (TEM) images show that 1-TiO_2-x and 2-TiO_2-x NPs are 5 nm in size, whereas X-ray photoelectron spectroscopy (XPS) reveals different Ti³⁺ (Ti²⁺)/Ti⁴⁺ ratios in the crystal lattices of synthesized NPs. 1-TiO_2-x nanoparticles contained 54% Ti⁴⁺, 38% Ti³⁺, and 8% Ti²⁺, while the relative amount of Ti⁴⁺ and Ti³⁺ in the crystal lattice of 2-TiO_2-x nanoparticles was 63% and 37%, respectively. Cell viability and cell motility induced by TiO_2-x nanoparticles were investigated on primary fibroblast cultures. Eryptosis modulation by the nanoparticles along with cell death mechanisms was studied on rat erythrocytes. We report that both TiO_2-x nanoparticles do not decrease the viability of fibroblasts simultaneously stimulating cell migration. Data from in vitro studies on erythrocytes indicate that TiO_2-x nanoparticles trigger eryptosis via ROS- (1-TiO_2-x) and Ca²⁺-mediated mechanisms (both TiO_2-x nanoparticles) suggesting that evaluation of eryptosis parameters is a more sensitive nanotoxicological approach for TiO_2-x nanoparticles than cultured fibroblast assays. TiO_2-x nanoparticles are characterized by low toxicity against fibroblasts, but they induce eryptosis, which is shown to be a promising tool for nanotoxicity screening. The Ti³⁺ (Ti²⁺)/Ti⁴⁺ ratio at least partly determines the cytotoxicity mechanisms for TiO_2-x nanoparticles.

Mancozeb-induced cytotoxicity in human erythrocytes: enhanced generation of reactive species, hemoglobin oxidation, diminished antioxidant power, membrane damage and morphological changes

Mancozeb is an ethylene bis-dithiocarbamate fungicide extensively used in agriculture to safeguard crops from various fungal diseases. The general population is exposed to mancozeb through consumption of contaminated food or water. Here, we have investigated the effect of mancozeb on isolated human erythrocytes under in vitro conditions. Erythrocytes were treated with different concentrations of mancozeb (0, 5, 10, 25, 50, 100 μM) and incubated for 24 h at 37 °C. Analysis of biochemical parameters and cell morphology showed dose-dependent toxicity of mancozeb in human erythrocytes. Mancozeb treatment caused hemoglobin oxidation and heme degradation. Protein and lipid oxidation were enhanced, while a significant decrease was seen in reduced glutathione and total sulfhydryl content. A significant increase in the generation of reactive oxygen and nitrogen species was detected in mancozeb-treated erythrocytes. The antioxidant capacity and the activity of key antioxidant enzymes were greatly diminished, while crucial metabolic pathways were inhibited in erythrocytes. Damage to the erythrocyte membrane on mancozeb treatment was apparent from increased cell lysis and osmotic fragility, along with the impairment of the plasma membrane redox system. Mancozeb also caused morphological alterations and transformed the normal discoid-shaped erythrocytes into echinocytes and stomatocytes. Thus, mancozeb induces oxidative stress in human erythrocytes, impairs the antioxidant defense system, oxidizes cellular components, that will adversely affect erythrocyte structure and function.

Dynamics of Human Hematopoietic Stem and Progenitor Cell Differentiation to the Erythroid Lineage

Erythropoiesis, the development of erythrocytes from hematopoietic stem cells, occurs through four phases: erythroid progenitor development, early erythropoiesis, terminal erythroid differentiation (TED), and maturation. According to the classical model that is based on immunophenotypic profiles of cell populations, each of these phases comprises multiple differentiation states that arise in a hierarchical manner. After segregation of lymphoid potential, erythroid priming begins during progenitor development and progresses through progenitor cell types that have multilineage potential. Complete separation of the erythroid lineage is achieved during early erythropoiesis with the formation of unipotent erythroid progenitors: burst forming unit-erythroid and colony forming unit-erythroid. These erythroid committed progenitors undergo TED and maturation, which involves expulsion of the nucleus and remodeling to form functional biconcave, hemoglobin-filled erythrocytes. In the last decade or so, many studies employing advanced techniques such as single cell RNA-sequencing (scRNA-seq) as well as the conventional methods, including colony forming cell assays and immunophenotyping, have revealed heterogeneity within the stem, progenitor, and erythroblast stages, and uncovered alternate paths for segregation of erythroid lineage potential. In this review, we provide an in-depth account of immunophenotypic profiles of all cell types within erythropoiesis, highlight studies that demonstrate heterogeneous erythroid stages, and describe deviations to the classical model of erythropoiesis. Overall, although scRNA-seq approaches have provided new insights, flow cytometry remains relevant and is the primary method for validation of novel immunophenotypes.

Semi-automated red blood cell core detection in blood micro-flow

In microcirculation, red blood cells (RBCs) tend to migrate toward the centre of the vessel leaving a region of a cell depleted layer or cell-free layer (CFL) at the vessel wall and a core of RBCs at the centre. This heterogenous distribution of cells has an effect on the blood apparent viscosity and the exchanges of gases and nutrients between the RBCs and the vessel. Understanding the formation of the CFL and obtaining accurate measurement of it is paramount for furthering development of devices such as drug administration. This paper presents a general semi-automatic method to quantify the thickness of the CFL for different channel geometries and image quality. It enables the use of a method based on intensity, a method using the gradient of the intensity, or a method based on spatiotemporal variation. The main features are reported, the performance is demonstrated on experimentally obtained image sets and accuracy is validated using synthetic images with known CFL thickness. A pure automatic detection is limited by the most visually correct using the spatiotemporal method, however proposed thresholding through automatic detection allows for quality controls through manual adjustments. With a semi-automatic approach RBC core variability between 3 % to 8 % was found when the test user was tasked with repeating the analysis of the same set. The presented method provides, users without programming ability with a user-friendly interface that can extract CFL automatically with quality control through manual adjustments.

Fish Erythrocyte Extracellular Traps (FEETs) are an evolutionarily conserved cellular process triggered by different stimuli

Fish erythrocytes remain nucleated, unlike mammalian erythrocytes that undergo enucleation during maturation. Besides oxygen transport, fish erythrocytes are capable of several immune defence processes and thus these cells are candidates for carrying out ETotic responses. ETosis is an evolutionarily conserved innate immune defence process found in both vertebrates and invertebrates, which involves the extrusion of DNA studded with antimicrobial effector proteins into the extracellular space that traps and kills microorganisms. In this present report, we demonstrate that erythrocytes from Danio rerio (zebrafish) produce ETotic-like responses when exposed to both chemical and physiological inducers of ETosis. Furthermore, erythrocytes from Salmo salar (Atlantic salmon) behaved in a similar way. We have termed these ET-like formations, as Fish Erythrocyte Extracellular Traps (FEETs). Several inducers of mammalian ETosis, such as the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) and the calcium ionophore ionomycin, induced FEETs. Moreover, we found that FEETs depend on the activation of PKC and generation of mitochondrial reactive oxygen species (mROS). This present report is the first demonstration that fish erythrocytes can exhibit ETotic-like responses, unveiling a previously unknown function, which sheds new light on the innate immune arsenal of these cells.

Validation of Blood Transfusion Risk Scores (TRACK and TRUST) in a Cardiac Surgery Service in Brazil

INTRODUCTION

Transfusion of red blood cells is recurrent in cardiac surgery despite the well-established deleterious effects. Identifying patients with higher chances of requiring blood transfusion is essential to apply strategic preventive measures to reduce such chances, considering the restricted availability of this product. The most used risk scores to predict blood transfusion are the Transfusion Risk and Clinical Knowledge (TRACK) and Transfusion Risk Understanding Scoring Tool (TRUST). However, these scores were not validated for the Brazilian population. The objective of this study was to assess the accuracy of TRACK and TRUST scores in estimating the need for postoperative transfusion of red blood cell concentrates (TRBCC) after cardiac surgery.

METHODS

A clinical retrospective study was conducted using the database of a Brazilian reference service composed of patients operated between November 2019 and September 2021. Scores were compared using Mann-Whitney U test. Hosmer-Lemeshow goodness of fit test assessed calibration of the scores. Accuracy was assessed using the area under the receiver operating characteristic curve (AUC). All analyses considered a level of significance of 5%. The study was approved by the research ethics committee (CAAE 55577421.4.0000.5201).

RESULTS

This study assessed 498 patients. Only the TRACK score presented good calibration (P=0.238; TRUST P=0.034). AUC of TRACK was 0.678 (95% confidence interval 0.63 to 0.73; P<0.001), showing a significant accuracy.

CONCLUSION

Between the scores analyzed, only the TRACK score showed a good calibration, but low accuracy, to predict postoperative TRBCC after cardiac surgery.

Innate immune response of rainbow trout erythrocytes to spinycterins expressing a downsized viral fragment of viral haemorrhagic septicaemia virus

Recent studies have reported on the importance of RBCs in fish responses to viral infections and DNA vaccines. Surface-displaying recombinant bacterins (spinycterins) are a safe and adaptable prototype for viral vaccination of fish and represent an alternative method of aquaculture prophylaxis, since have been reported to enhance fish immune response. We evaluated the innate immune response of rainbow trout (Oncorhynchus mykiss) red blood cells (RBCs), head kidney, and spleen to spinycterins expressing a fragment of the glycoprotein G of viral haemorrhagic septicemia virus (VHSV), one of the most devastating world-wide diseases in farmed salmonids. We first selected an immunorelevant downsized viral fragment of VHSV glycoprotein G (frg16252-450). Then, spinycterins expressing frg16252-450 fused to Nmistic anchor-motif (Nmistic+frg16252-450) were compared to spinycterins expressing frg16252-450 internally without the anchor motif. Nmistic+frg16252-450 spinycterins showed increased attachment to RBCs in vitro and modulated the expression of interferon- and antigen presentation-related genes in RBCs in vitro and in vivo, after intravenous injection. In contrast, the head kidney and spleen of fish injected with frg16252-450, but not Nmistic+frg16252-450, spinycterins demonstrated upregulation of interferon and antigen-presenting genes. Intravenous injection of Nmistic+frg16252-450 spinycterins resulted in a higher innate immune response in RBCs while frg16252-450 spinycterins increased the immune response in head kidney and spleen. Although more studies are required to evaluate the practicality of using spinycterins as fish viral vaccines, these results highlight the important contribution of RBCs to the fish innate immune response to antiviral prophylactics.

Current status of red blood cell manufacturing in 3D culture and bioreactors

Owing to donor-related issues, blood shortages and transfusion-related adverse reactions have become global issues of grave concern. In vitro manufactured red blood cells (RBCs) are promising substitutes for blood donation. In the United Kingdom, a clinical trial for allogeneic mini transfusion of cultured RBCs derived from primary hematopoietic stem cells has recently begun. However, current production quantities are limited and need improved before clinical use. New methods to enhance manufacturing efficiencies have been explored, including different cell sources, bioreactors, and 3-dimensional (3D) materials; however, further research is required. In this review, we discuss various cell sources for blood cell production, recent advances in bioreactor manufacturing processes, and the clinical applications of cultured blood.

Sex differences in cadmium and lead concentrations in different biological matrices in athletes. Relationship with iron status

PURPOSE

The present study aimed to analyse sex differences in cadmium and lead concentrations in plasma, urine, platelets and erythrocytes and to relate these concentrations to biomarkers of iron status.

METHODS

A total of 138 soccer players divided according to sex: men (n = 68) and women (n = 70) participated in the present study. All participants resided in the city of Cáceres (Spain). Erythrocyte, haemoglobin, platelet, plateletcrit, ferritin and serum iron values were determined. Cadmium and lead concentrations were quantified by inductively coupled plasma mass spectrometry.

RESULTS

The women had lower haemoglobin, erythrocyte, ferritin and serum iron values (p < 0.01). Regarding cadmium, the women showed higher concentrations in plasma, erythrocytes and platelets (p < 0.05). As for lead, they also showed higher concentrations in plasma, relative values of erythrocytes and relative values of platelets (p < 0.05). Significant correlations were observed between cadmium and lead concentrations with biomarkers of iron status.

CONCLUSIONS

Cadmium and lead concentrations are different between sexes. Biological differences between sexes and iron status could influence cadmium and lead concentrations. Lower serum iron concentrations and markers of Fe status increase Cd and Pb concentrations. Ferritin and serum iron have been directly related to increased Cd and Pb excretion.

Polo-like kinase inhibitor BI2536 induces eryptosis

BI2536 is potent inhibitor of polo-like kinases PLK1, 2, and 3. The inhibition of PLKs in nucleated cells induces apoptosis by perturbing the cell cycle with consequent engagement of mitotic catastrophe. BI2536 is being tested as chemotherapy in various phase I/II/III clinical trials. Erythrocytes do not have a nucleus; however, they may undergo programmed suicide with characteristic hallmarks including cell shrinkage and phosphatidylserine translocation to the cell surface. This particular death is baptized eryptosis. Our study explored whether BI2536 induces eryptosis. We used flow cytometry to access death in red blood cells. We analyzed the cellular volume, the intracellular calcium concentration, the cell surface phosphatidylserine exposure, and the ceramide abundance. In addition, we analyzed the effect of BI2536 on hemolysis. Our investigation showed that after 48 h of incubation with PLK inhibitor BI2536, erythrocytes lost volume and were positive for annexin‑V without any effect on hemolysis. Cells also showed an abundance of ceramide and an increase of intracellular calcium. All these finding suggest that BI2536 provokes eryptosis in red blood cells, ostensibly in part due to Ca2+ entry and ceramide accumulation.

Esculin protects human blood cells from bioallethrin-induced toxicity: An ex vivo study

Bioallethrin, a household insecticide, is a member of the pyrethroid family and is known for its adverse effects on human health. Human exposure to pyrethroids is unavoidable due to their widespread use in controlling several fatal vector-borne diseases, mostly in developing nations. Bioallethrin is known to induce oxidative stress in target cells, including erythrocytes. Here we have studied the protective effect of dietary antioxidant esculin on bioallethrin-induced damage in isolated human erythrocytes. The cells were incubated with 200 μM bioallethrin, without or with different concentrations of esculin (200, 400 and 600 μM), and the results compared to the untreated control samples. Bioallethrin-treated erythrocytes showed a significant increase in oxidative stress markers, like protein and lipid oxidation, accompanied by decrease in free amino groups and ratio of reduced to oxidized glutathione. There was enhanced generation of reactive oxygen and nitrogen species with changes in plasma membrane integrity. Bioallethrin oxidized hemoglobin to methemoglobin, which cannot transport oxygen. It altered the activities of antioxidant enzymes and lowered the electron donating and free radical quenching ability of erythrocytes. The cell morphology and redox system of erythrocyte membrane were also altered by bioallethrin. Treatment with esculin, prior to incubation with bioallethrin, led to significant restoration in all these parameters in an esculin concentration-dependent manner. Thus esculin attenuated the biolletherin-induced oxidative damage to erythrocytes. Esculin can, therefore, be an effective chemoprotectant against xenobiotic-induced toxicity in human erythrocytes.

Haemato-biochemical, mutagenic, and histopathological changes in Oreochromis niloticus exposed to BTX

The study of the DNA damage response in erythrocytes after exposure to volatile organic compounds (VOCs) can present evidence for its potential effect as genotoxic- biomarkers for environmental pollution. Although VOCs are dangerous pollutants, still little is known about hemotoxic, cytotoxic, and genotoxic effects of such pollutants on fish. We optimized an assay method for apoptosis and DNA damage in erythrocytes of adult tilapia fish after 15 days exposure to benzene (0.762 ng/L), toluene (26.614 ng/L), and xylene (89.403 ng/L). The highest level of apoptosis and DNA damage were recorded in benzene-exposed fish, as was the highest level of histopathological alterations in gills, liver, and kidney. The imbalance of the antioxidants profile explained the stress-case reported in exposed fish. These results suggest that hemotoxic, cytotoxic, genotoxic, and tissue damage were recorded after exposure to BTX in Oreochromis niloticus.