Human Red Blood Cells Research Articles

Red blood cells as potential materials for microRNA biomarker study: overcoming heparin-related challenges.

microRNAs (miRNAs) have been intensively studied as valuable biomarkers in cardiometabolic disease. Typically, miRNAs are detected in plasma or serum but the use of samples collected in heparinized tubes is problematic for miRNA studies utilizing qPCR. Heparin and its derivatives interfere with qPCR-based analysis, leading to a substantial reduction or even complete loss of detectable miRNA levels. Given that red blood cells (RBCs) express abundant miRNAs, whose expression is altered in cardiometabolic disease, RBCs could serve as an attractive alternative in biomarker studies. Here, we aim to explore the stability of miRNAs in RBCs collected from whole blood with different anticoagulants and thereby the potential of RBCs as alternative materials for miRNA biomarker studies. miRNA profiling was performed in human RBCs via RNA sequencing, followed by qPCR validation of selected miRNAs in RBCs and plasma in both heparinized and EDTA tubes. RNA sequencing revealed abundant miRNA presence in RBCs isolated from blood collected in EDTA tubes. miR-210-3p, miR-21-5p, miR-16-5p, and miR-451a were detected at comparable levels in RBCs isolated from both heparinized and EDTA tubes, but not in plasma from heparinized tubes. Of note, miR-210 levels were consistently lower in RBCs from individuals with type 2 diabetes compared to healthy controls, regardless of anticoagulant type, supporting their potential as biomarker materials. In conclusion, RBCs offer a promising alternative for miRNA biomarker studies, overcoming heparin-related challenges.

Effect of Moderate Beer Intake on the Lipid Composition of Human Red Blood Cell Membranes.

Background/Objectives: Growing evidence suggests that erythrocyte membrane lipids are subject to changes during their lifespan. Factors such as the type of dietary intake and its composition contribute to the changes in red blood cell (RBC) membranes. Due to the high antioxidant content of beer, we aimed to investigate the effect of moderate beer consumption on the lipid composition of RBCs membranes from healthy overweight individuals. Methods: We conducted a four-weeks, prospective two-arm longitudinal crossed-over study, where participants (n = 36) were randomly assigned to alcohol-free beer group or traditional beer group. The lipids of RBCs membranes were assessed at the beginning and the end of the intervention by thin-layer chromatography. Results: Four-weeks of alcohol-free beer promoted changes in fatty acids (FA), free cholesterol (FC), phosphatidylethanolamine (PE) and phosphatidylcholine (PC) (p < 0.05). Meanwhile, traditional beer intake led to changes in FA, FC, phospholipids (PL), PE and PC (p < 0.05). The observed alterations in membrane lipids were found to be independent of sex and BMI as influencing factors. Conclusions: The lipid composition of erythrocyte membranes is distinctly but mildly influenced by the consumption of both non-alcoholic and conventional beer, with no effects on RBC membrane fluidity.

On-demand imidazolidinyl urea-based tissue-like, self-healable, and antibacterial hydrogels for infectious wound care

Bacterial wound infections are a growing challenge in healthcare, posing severe risks like systemic infection, organ failure, and sepsis, with projections predicting over 10 million deaths annually by 2050. Antibacterial hydrogels, with adaptable extracellular matrix-like features, are emerging as promising solutions for treating infectious wounds. However, the antibacterial properties of most of these hydrogels are largely attributed to extrinsic agents, and their mechanisms of action remain poorly understood. Herein we introduce for the first time, modified imidazolidinyl urea (IU) as the polymeric backbone for developing tissue-like antibacterial hydrogels. As-designed hydrogels behave tissue-like mechanical features, outstanding antifreeze behavior, and rapid self-healing capabilities. Molecular dynamics (MD) simulation and density functional theory (DFT) calculation were employed to well-understand the extent of H-bonding and metal-ligand coordination to finetune hydrogels’ properties. In vitro studies suggest good biocompatibility of hydrogels against mouse fibroblasts & human skin, lung, and red blood cells, with potential wound healing capacity. Additionally, the hydrogels exhibit good 3D printability and remarkable antibacterial activity, attributed to concentration dependent ROS generation, oxidative stress induction, and subsequent disruption of bacterial membrane. On top of that, in vitro biofilm studies confirmed that developed hydrogels are effective in preventing biofilm formation. Therefore, these tissue-mimetic hydrogels present a promising and effective platform for accelerating wound healing while simultaneously controlling bacterial infections, offering hope for the future of wound care.

Comparison of Essential Oils of Schinus molle L. Leaves Growing in Different Regions of Algeria in Terms of Their Chemical Compositions and Various Biological Activities

ABSTRACTThis preliminary study investigated the chemical composition and biological properties of essential oils derived from Schinus molle L. leaves obtained from three specific regions in Algeria: Algiers (SMA), Djelfa (SMD), and Mascara (SMM). Gas chromatography (GC) and Gas chromatography–Mass Spectrometry (GC–MS) analyses confirmed the presence of 52 compounds (100.0%) in SMA essential oil, 50 compounds (100.0%) in SMD, and 72 compounds (100.0%) in SMM essential oils. The main components of SMA oil were camphene (31.82%), limonene (14.71%), and p‐cymene (9.25%). In SMD and SMM oils, α‐phellandrene (14.25% and 12.70%), limonene (13.02% and 11.90%), and germacrene D (10.62% and 10.15%) were the major components, respectively. The antioxidant characteristics were evaluated using five methods: β‐carotene‐linoleic acid, DPPH, ABTS+, CUPRAC, and Metal chelating assays. The results revealed a moderate to low anti‐oxidant effect, with SMA essential oils exhibiting the highest activity. A moderate inhibitory effect against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α‐glucosidase, α‐amylase, urease, and tyrosinase was observed, indicating anti‐enzymatic activity. Nevertheless, all samples had higher IC50 values for both antioxidant and anti‐enzymatic activities than 200 μg/mL. It was determined that regional differences in the locations where S. molle grows showed both qualitative and quantitative differences in essential oil components. This difference was also detected in the biological activities of the essential oils. The anti‐inflammatory capacities of the three samples were assessed using Human Red Blood Cell (HRBC) membrane stabilisation and egg albumin denaturation techniques. The results showed effective anti‐inflammatory activity in all three samples. The antimicrobial efficacy was evaluated using a range of tests, such as anti‐quorum sensing, violacein inhibition, anti‐swimming, and anti‐swarming assays, demonstrating moderate activity. No toxic effects were observed at the tested dosages when assessing cytotoxicity against a healthy cell line (CCD18‐Co). This thorough examination provides valuable insights into the chemical composition and bioactive properties of essential oils derived from S. molle. These findings indicate the possible use of these essential oils in the food, medicinal, and cosmetic industries.

Thermomechanical properties of bat and human red blood cells—Implications for hibernation

Hibernation is a widespread and highly efficient mechanism to save energy in mammals. However, one major challenge of hibernation is maintaining blood circulation at low body temperatures, which strongly depends on the viscoelastic properties of red blood cells (RBCs). Here, we examined at physiologically relevant timescales the thermomechanical properties of hundreds of thousands of individual RBCs from the hibernating common noctule bat (Nyctalus noctula), the nonhibernating Egyptian fruit bat (Rousettus aegyptiacus), and humans (Homo sapiens). We exposed RBCs to temperatures encountered during normothermia and hibernation and found a significant increase in elasticity and viscosity with decreasing temperatures. Our data demonstrate that temperature adjustment of RBCs is mainly driven by membrane properties and not the cytosol while viscous dissipation in the membrane of both bat species exceeds the one in humans by a factor of 15. Finally, our results show that RBCs from both bat species reveal a transition to a more viscous-like state when temperature decreases. This process on a minute timescale has an effect size that is comparable with fluctuations in RBC viscoelasticity over the course of the year, implying that environmental factors, such as diets, have a lower impact on the capability of RBCs to respond to different temperatures than general physical properties of the cell membrane. In summary, our findings suggest membrane viscoelasticity as a promising target for identifying mechanisms that could be manipulated to ensure blood circulation at low body temperatures in humans, which may be one first step toward safe synthetic torpor in medicine and space flight.

Evaluating different methods for kidney recellularization

This study explores a potential solution to the shortage of kidneys for transplantation in end-stage renal disease (ESRD). Currently, kidney transplantation stands as the optimal option, yet the scarcity of organs persists. Employing tissue engineering, researchers sought to assess the feasibility of generating kidneys for transplantation. Pig kidneys were utilized since they possess higher similarities to human kidneys. Cells were removed via decellularization, which maintains the organ’s microarchitecture. Subsequently, pig kidney cells and human red blood cells were perfused into the vacant kidney structure to reconstitute it. The methodologies employed showed promising results, suggesting a viable approach to increase the recellularization rate in whole pig kidneys. This proof-of-concept establishes a groundwork for potentially extending this technology to human kidneys, tackling the organ shortage, thus positively enhancing outcomes for ESRD patients by increasing the availability of transplantable organs.

Evaluation of the in vitro toxicity and anti-inflammatory activity of the methanolic extract of the leaves of Pistacia lentiscus L. harvested from northwestern Algeria.

Medicinal and aromatic plants have been used for thousands of years for their therapeutic properties, to treat various ailments and maintain health. This study was carried out to test the in vitro toxicity and anti-inflammatory activity of the methanolic extract of the leaves of Pistacia lentiscus L., native to the north-western region of Algeria. Toxicity was studied in vitro by the hemolysis test and anti-hemolytic activity on human red blood cells, while anti-inflammatory activity was assessed in vitro by the protein denaturation method. The study of toxicity by hemolysis of red blood cells showed a high rate of hemolysis at a dose of 200 mg/mL, with a hemolytic percentage of around 88.64%, while a high rate of anti-hemolysis was observed at a dose of 25 mg/mL, with an inhibition percentage of around 83.17%. Evaluation of anti-inflammatory activity revealed a high percentage of inhibition of ovalbumin denaturation, reaching 63.53% at the 2000 ug/mL dose, while the lowest percentage was obtained at the 3500 ug\mL concentration with 10.16%. This extract has a toxic substance but does not exceed the toxicity threshold which achieves significant anti-inflammatory activity with depandant doses.

Peripheral human red blood cell development in human immune system mouse model with heme oxygenase-1 deficiency

AbstractA challenge for human immune system (HIS) mouse models has been the lack of human red blood cell (hRBC) survival after engraftment of these immune-deficient mice with human CD34+ hematopoietic stem cells (HSCs). This limits the use of HIS models for preclinical testing of targets directed at hRBC-related diseases. Although human white blood cells can develop in the peripheral blood of mice engrafted with human HSCs, peripheral hRBCs are quickly phagocytosed by murine macrophages upon egress from the bone marrow. Genetic ablation of murine myeloid cells results in severe pathology in resulting mice, rendering such an approach to increase hRBC survival in HIS mice impractical. Heme oxygenase-1 (HMOX-1)–deficient mice have reduced macrophages due to toxic buildup of intracellular heme upon engulfment of RBCs, but do not have an overall loss of myeloid cells. We took advantage of this observation and generated HMOX-1–/– mice on a humanized M-CSF/SIRPα/CD47 Rag2–/– IL-2Rγ–/– background. These mice have reduced murine macrophages but comparable levels of murine myeloid cells to HMOX-1+/+ control mice in the same background. Injected hRBCs survive longer in HMOX-1–/– mice than in HMOX-1+/+ controls. Additionally, upon human HSC engraftment, hRBCs can be observed in the peripheral blood of HMOX-1–/– humanized M-CSF/SIRPα/CD47 Rag2–/– IL-2Rγ–/– mice, and hRBC levels can be increased by treatment with human erythropoietin. Given that hRBC are present in the peripheral blood of engrafted HMOX-1–/– mice, these mice have the potential to be used for hematologic disease modeling, and for testing therapeutic treatments for hRBC diseases in vivo.

Anti-hypertensive, anti-inflammatory, glycemic and satiety impact of cocoa flavoured soy-based powder drink mix enriched with bioactive hydrolysates from nests of Aerodramus fuciphagus

Abstract Objectives The edible bird’s nest hydrolysates (EBNH) are renowned for their health benefits. The study aimed to determine their contributory functional effect as an ingredient in the cocoa-flavoured soy-based powder drink mix (PDM). The product’s glycemic and satiety impact were also studied. Materials and Methods The product was enriched with a reasonably low amount of spray-dried EBNH. The product’s functional effect with respect to in vitro angiotensin converting enzyme (ACE) inhibitory activity and human red blood cells membrane stabilization (RBCMS) activity were evaluated, using its water extract (90 - 95 oC). The glycemic and satiety impact were evaluated using 12 and 30 subjects, respectively, who consumed 250 mL of the product, containing 25 g of available carbohydrates. Results The enriched PDM’s ACE inhibitory activity and RBCMS activity were significantly higher (p&amp;lt;0.05) than those that were devoid of EBNH. A 240 mL (12.5% w/v) of PDM (containing by weight 3.0% EBNH, 75.44% soybean powder, 20% cocoa powder, 0.5% xanthan gum, 1.0% silicon dioxide and 0.06% sucralose) provides about 3.7 kcal/g energy. Its 250 mL meal (consistency index of 14.17 Pa.sn) is high in protein and dietary fiber. The product’s glycemic index (GI) and glycemic load (GL) are low, 24 and 6.0, respectively, raising a normal level of 2 hours postprandial blood glucose (&amp;lt;6 mmol/L) and satisfies hunger for about 2.5 hours. Conclusion The EBNH, as an ingredient, enhances the PDM’s anti-hypertensive and anti-inflammatory properties. The overall findings suggest that the formulated PDM is a wellness food product capable of promoting good human health, including for dieters and individuals with diabetes.

Measurement and analysis of ionic leakage profiles in refrigerated human red blood cells using dielectrophoresis and inductively coupled mass spectroscopy.

Human red blood cells (RBCs) undergo ionic leakage through passive diffusion during refrigerated storage, affecting their quality and health. We investigated the dynamics of ionic leakage in human RBCs over a 20-day refrigerated storage period using extracellular ion quantification and dielectrophoresis (DEP). Four type O- human blood donors were examined to assess the relationship between extracellular ion concentrations (Na+, K+, Mg2+, Ca2+, and Fe2+), RBC cytoplasm conductivity, and membrane conductance. A consistent negative correlation between RBC cytoplasm conductivity and membrane conductance, termed the "ionic leakage profile" (ILP), was observed across the 20-day storage period. Specifically, we noted a gradual decline in DEP-measured RBC cytoplasm conductivity alongside an increase in membrane conductance. Further examination of the electrical origins of this ILP using inductively coupled plasma mass spectrometry revealed a relative decrease in extracellular Na+ concentration and an increase in K+ concentration over the storage period. Correlation of these extracellular ion concentrations with DEP-measured RBC electrical properties demonstrated a direct link between changes in the cytoplasmic and membrane domains and the leakage and transport of K+ and Na+ ions across the cell membrane. Our analysis suggests that the inverse correlation between RBC cytoplasm and membrane conductance is primarily driven by the passive diffusion of K+ from the cytoplasm and the concurrent diffusion of Na+ from the extracellular buffer into the membrane, resulting in a conductive reduction in the cytoplasmic domain and a subsequent increase in the membrane. The ILP's consistent negative trend across all donors suggests that it could serve as a metric for quantifying blood bank storage age, predicting the quality and health of refrigerated RBCs.

Characterization of two Plasmodium falciparum lipid transfer proteins of the Sec14/CRAL-TRIO family

Invasion of human red blood cells by the malaria parasite Plasmodium falciparum is followed by dramatic modifications of erythrocytes properties, including de novo formation of new membrane systems. Lipid transfer proteins from both the parasite and the host cell are most likely an important part of those membrane remodeling processes. Using bioinformatics and in silico structural analysis, we have identified five P. falciparum potential lipid transfer proteins containing cellular retinaldehyde binding – triple functional domain (CRAL-TRIO). Two of these proteins, C6KTD4, encoded by the PF3D7_0629900 gene and Q8II87, encoded by the PF3D7_1127600 gene, were studied in more detail. In vitro lipid transfer assays using recombinant C6KTD4 and Q8II87 confirmed that these proteins are indeed bona fide lipid transfer proteins. C6KTD4 transfers sterols, phosphatidylinositol 4,5 bisphosphate, and, to some degree, also phosphatidylcholine between two membrane compartments. Q8II87 possesses phosphatidylserine transfer activity in vitro. In the yeast model, the expression of P. falciparumQ8II87 protein partially complements the absence of Sec14p and its closest homologue, Sfh1p. C6KTD4 protein can substitute for the collective essential function of oxysterol-binding related proteins. According to published whole genome studies in P. falciparum, absence of C6KTD4 and Q8II87 proteins has severe consequences for parasite viability. Therefore, CRAL-TRIO lipid transfer proteins of P. falciparum are potential targets of novel antimalarials, in search for which the yeast model expressing these proteins could be a valuable tool.

A Convolutional Neural Network- Based Deep Learning To Detect Reticulocytes From Human Peripheral Blood

Machine learning approaches are rapidly augmenting, and in some cases, replacing the conventional methods in biomedical data analysis; to reduce time, cost, biases, and the need for sophisticated analytical platforms. Hence, significant interest has been compounded in the integration of automated image analysis for various clinical applications, such as the detection of infected or inflamed wounds, bone fractures or for the purpose of disease diagnosis – such as Plasmodium parasites or circulating tumour cells in blood. Here, we report the development of a Convolutional Neural Network (CNN)-based method on CPU to distinguish and count immature human red blood cells known as reticulocytes from blood smears. Reticulocytes represent a heterogeneous and relatively small percentage of cells in peripheral blood, and contain residual RNA in complex with proteins which generates thread-like patterns when stained with New Methylene Blue (NMB) dye. We used more than 200 NMB-stained images from leukocyte-depleted blood to train and optimize the model for immature reticulocytes (stained positive with NMB, intensity and pattern of which depends on the developmental stage of the reticulocyte) and mature RBCs (no staining with NMB). The training performance evaluation metrics demonstrated a mean average precision (mAP50) of 0.88, a precision of 0.83, a recall of 0.88, and an F1 score of 0.87. Our model was able to successfully count reticulocytes with accuracy more than 90% from unknown samples which were subsequently cross-verified through microscopy and counting. Given the importance of reticulocyte dynamics in blood and its clinical relevance, the newly developed model will find important easy to adopt biomedical applications that can be achieved on a simple PC.

Synthesis of 2-Phenoxyacetic Acid Analogs for Evaluation of the Anti-inflammatory Potential and Subsequent &lt;i&gt;In Silico&lt;/i&gt; Analysis

Several 2-phenoxyacetic acid derivatives and their isosteres were synthesized in moderate to high yield (57–96%) for searching newer and safer alternatives to these existing anti-inflammatory agents. The compounds were characterized by 1H-NMR, 13C-NMR and HRMS. The synthesized compounds have been subjected to in vitro anti-inflammatory activity using egg albumin denaturation and human red blood cell membrane stabilization methods. The compounds were also evaluated for their anti-inflammatory activity in the mice model. The synthesized compounds were subsequently subjected to docking analysis. The in vitro pharmacokinetic properties were analyzed by applying the pkCSM software and drug-likeness was checked by using Lipinski’s rule. Some synthesized esters and amides, like SM61, SM81, SM82, SM83, SM91 and SM101, were significantly more powerful as anti-inflammatory agents. The efficacies were correlated with their orientations in the binding pocket of the cyclooxygenase enzyme. The encouraging in vitro and in vivo activities, the optimum pharmacokinetic profile, and good drug-likeness indicated that these scaffolds could be considered for future discovery of newer nonsteroidal anti-inflammatory drugs (NSAIDs).

Antimicrobial and Anti-Inflammatory Potential of Euphorbia paralias (L.): a bioprospecting study with phytoconstituents analysis.

The phytochemicals in the aerial parts of Euphorbia paralias (also known as Sea Spurge) and their anti-inflammatory and antimicrobial activities were investigated. The methanolic extract was characterized using GC-MS and HPLC techniques. The anti-inflammatory feature was estimated through a Human Red Blood Cell (HRBC) membrane stabilization technique, while the antimicrobial feature was evaluated by the disc diffusion agar technique, minimum bactericidal concentration, and minimum inhibitory concentration (MIC) via micro-broth dilution method. The GC/MS results demonstrated the existence of various phytochemicals, such as n-hexadecenoic acid, cis-11-eicosenoic acid, and methyl stearate, recognized for their anti-inflammatory and antibacterial features. The similarity of the phytochemical composition with other Euphorbia species emphasizes the genus-wide similarity. The anti-inflammatory activity exhibited a noteworthy inhibitory effect comparable to the reference drug indomethacin. The extract's antimicrobial potential was tested against a range of microorganisms, demonstrating significant action against Gram-positive bacteria and Candida albicans. The quantification of total phenolics and flavonoids further supported the therapeutic potential of the extract. The methanolic extract from E. paralias emerges as a successful natural source of important active constituents with potential applications as anti-inflammatory and antimicrobial agents. This research provides a first step to valorize Euphorbia paralias insights as a source of worthwhile phytochemicals that have potential applications in the pharmaceutical industry.

Exploring the Potential of New 7‐Chloroquinoline‐benzylamine Hybrids as Antimicrobials: Synthesis, Biological Activity and MD Simulation Studies

AbstractNovel drug like chloroquinoline‐benzylamine hybrids were synthesized and subjected to comprehensive antibacterial evaluation in the present investigation. The pharmacological evaluation comprises determination of minimum inhibitory concentration (MIC), disk diffusion assay, hemolysis and combination assays against both Gram‐negative (Pseudomonas aeruginosa) and Gram‐positive (Bacillus subtilis, Enterococcus faecalis, and Staphylococcus aureus) bacterial strains. Among all, 7‐chloroquinoline‐benzylamine hybrid bearing p‐bromophenyl substituent (SA11) demonstrated significant antibacterial efficacy (MIC=128μg/mL) against the tested panel of Gram‐positive strains with no sign of toxicity towards human red blood cells (hRBCs). Furthermore, another hybrid with o‐hydroxyphenyl substitution (SA12) exhibited notable activity against the tested isolates with MIC values ranging from 64 to 256μg/mL. Molecular docking studies suggested compound SA11 binds within the active site of the biofilm causing protein (PDB: 7C7U) further supported by the molecular dynamics (MD) simulation studies at 100 ns. Compound SA11 exhibited significant efficacy in inhibiting S. aureus growth in the disk diffusion assay. Moreover, it displayed a synergistic effect when combined with ciprofloxacin (CIP), implying its potential utility in addressing antibiotic‐resistant bacterial strains through combination therapy. The pkCSM‐Pharmacokinetics assessment indicated favourable ADME profiles for SA11, supporting its potential as a viable drug candidate.

β-Citronellol: a potential anti-inflammatory and gastro-protective agent-mechanistic insights into its modulatory effects on COX-II, 5-LOX, eNOS, and ICAM-1 pathways through in vitro, in vivo, in silico, and network pharmacology studies

BackgroundThe current study aimed to evaluate the anti-inflammatory, anti-oxidant, and pronounced gastro-protective activities of β- Citronellol using in vitro, in vivo assays and in silico approaches.MethodsIn vitro assays, denaturation of bovine serum albumin, egg protein, and human Red Blood Cells (RBCs) membrane stabilization were performed, using Piroxicam as standard. For in vivo assessment, Histamine (0.1 ml from 1% w/v) and Formaldehyde (0.1 ml from 2% v/v) were used to mediate inflammation. In silico molecular docking and network pharmacology were employed to probe the possible target genes mediating gastroprotective effect of β-Citronellol at 25, 50, and 100 mg/kg, using indomethacin-induced (25 mg/kg i.p) gastric ulcer in rats. Moreover, Gastric tissues were evaluated for morphological, histopathological, and bio-chemical analysis of PGE2, COX-I, COX-II, 5-LOX, eNOS, ICAM-1, oxygen-free radical scavengers (SOD, CAT), and oxidative stress marker (MDA).Resultsβ-Citronellol prevented denaturation of proteins and RBCs membrane stabilization with maximum effect observed at 6,400 µg/mL. Citronellol decreased rat’s paw edema. Network pharmacology and docking studies revealed gastro-protective potential of Citronellol possibly mediated through arachidonic acid pathways by targeting COX-I, COX-II, PGE2, and 5-LOX. Citronellol reduced the ulcer indices, and histopathological changes. Further, β-Citronellol (50 and 100 mg/kg) increased gastric PGE2, COX-1, and eNOS; while suppressing COX-2, 5-LOX and ICAM-1. Citronellol markedly enhanced the oxidative balance in isolated rat stomach tissues.ConclusionsThe anti-inflammatory, anti-oxidant, and gastro-protective effects of β-Citronellol against indomethacin-induced gastric ulcer model in rats through mediating COX-I, COX-II, PGE2, 5-LOX, eNOS, and ICAM-1 inflammatory markers.Graphical abstract

Genetic identification of methicillin resistant Staphylococcus aureus (MRSA) isolated from diabetic foot ulcers and evaluating the inhibition activity of reuterin against this bacteria.

To genetically diagnose the isolates of methicillin-resistant staphylococcus aureus taken from patients with severe diabetic foot infections, and to test the inhibitory effect of reuterin on the growth of these bacteria. The experimental study was conducted from June to November 2021 at the Diabetes Unit of Al-Faihaa General Hospital, Basrah, Iraq, and comprised 62 foot ulcer swabs from the necrotic lesions of patients with type 2 diabetes. The swabs were cultivated first in brain heart infusion broth media, and then streaked on Mannitol salt agar and staphylococcus chromogeneic agar media for phenotypic and genetic analysis. The genetic identification of bacteria was confirmed by deoxyribonucleic acid extraction, and methicillin-resistant staphylococcus aureus was confirmed by the presence of plasmid mecA gene. The inhibition activity of reuterin towards methicillin-resistant staphylococcus aureus was determined using the minimum inhibitory concentration test. All data was analyzed with SPSS version 23. A total of 62 swabs were taken from the necrotic lesions of type 2 diabetes mellitus (T2DM) patients with diabetic foot ulcers. Of the total isolates, 9(14.5%) gave mauve to purple colour on staphylococcus chromogeneic agar, which was then genetically confirmed as methicillin-resistant staphylococcus aureus. The minimum inhibitory concentration value of these bacteria was 10μl/ml at 16mm inhibition zone diameter. There was no cytotoxicity of reuterin to human red blood cells. Reuterin was found to be a natural antimicrobial substance suitable for use to disinfect diabetic foot wounds from bacterial contamination and infection, especially those caused by methicillin-resistant staphylococcus aureus.

Numerical-experimental estimation of the deformability of human red blood cells from rheometrical data

The deformability of human red blood cells (RBCs), which comprise almost 99% of the cells in whole blood, is largely related not only to pathophysiological blood flow but also to the levels of intracellular compounds. Therefore, statistical estimates of the deformability of individual RBCs are of paramount importance in the clinical diagnosis of blood diseases. Although the microscale hydrodynamic interactions of individual RBCs lead to non-Newtonian blood rheology, there is no established method to estimate individual RBC deformability from the rheological data of RBC suspensions, and the possibility of this estimation has not been proven. To address this issue, we conducted an integrated analysis of a model of the rheology of RBC suspensions, coupled with macrorheological data of human RBCs suspended in plasma. Assuming a nonlinear curve of the relative viscosity of the suspensions as a function of the cell volume fraction, the statistical average of the membrane shear elasticity was estimated for individual intact RBCs or hardened RBCs. Both estimated values reproduced well the experimentally observed shear-thinning non-Newtonian behavior in these suspensions. We hereby conclude that our complementary approach makes it possible to estimate the statistical average of individual RBC deformability from macrorheological data obtained with usual rheometric tests.

Plasmodium RON11 triggers biogenesis of the merozoite rhoptry pair and is essential for erythrocyte invasion.

Malaria is a global and deadly human disease caused by the apicomplexan parasites of the genus Plasmodium. Parasite proliferation within human red blood cells (RBCs) is associated with the clinical manifestations of the disease. This asexual expansion within human RBCs begins with the invasion of RBCs by P. falciparum, which is mediated by the secretion of effectors from 2 specialized club-shaped secretory organelles in merozoite-stage parasites known as rhoptries. We investigated the function of the Rhoptry Neck Protein 11 (RON11), which contains 7 transmembrane domains and calcium-binding EF-hand domains. We generated conditional mutants of the P. falciparum RON11. Knockdown of RON11 inhibits parasite growth by preventing merozoite invasion. The loss of RON11 did not lead to any defects in processing of rhoptry proteins but instead led to a decrease in the amount of rhoptry proteins. We utilized ultrastructure expansion microscopy (U-ExM) to determine the effect of RON11 knockdown on rhoptry biogenesis. Surprisingly, in the absence of RON11, fully developed merozoites had only 1 rhoptry each. The single rhoptry in RON11-deficient merozoites were morphologically typical with a bulb and a neck oriented into the apical polar ring. Moreover, rhoptry proteins are trafficked accurately to the single rhoptry in RON11-deficient parasites. These data show that in the absence of RON11, the first rhoptry is generated during schizogony but upon the start of cytokinesis, the second rhoptry never forms. Interestingly, these single-rhoptry merozoites were able to attach to host RBCs but are unable to invade RBCs. Instead, RON11-deficient merozoites continue to engage with RBC for prolonged periods eventually resulting in echinocytosis, a result of secreting the contents from the single rhoptry into the RBC. Together, our data show that RON11 triggers the de novo biogenesis of the second rhoptry and functions in RBC invasion.

Highly oxygenated antiplasmodial and non-hemolytic Δ7,9(11) stigmastane-type steroids from the twigs of Vernonia amygdalina Delile

Chemical investigations of a methanolic extract of the twigs of Vernonia amygdalina Delile (Asteraceae) resulted in the isolation and identification of three previously undescribed highly oxygenated Δ7,9(11) stigmastane-type steroids namely vernonins U−W (1−3) along with six known compounds (4−9). The structural characterization of all the isolated compounds has been conducted via comprehensive 1D- and 2D-NMR spectroscopy as well as HRMS. The seven steroidal derivatives 1−7 were evaluated for their antiplasmodial activity against the chloroquine-resistant strain P. falciparum Dd2 (PfDd2) and their hemolytic effect on human red blood cells (RBCs). Vernonins U (1), A (4) and stigmasterol-3-O-β-D-glucopyranoside (7) showed the highest activity with IC50 values of (5.47 ± 0.01) μg/mL, (6.02 ± 0.13) μg/mL and (6.34 ± 0.80) μg/mL, respectively, against PfDd2, while vernonin W (3) showed moderate activity of (21.20 ± 0.40) μg/mL. None of the tested compounds displayed hemolytic effects on human RBCs up to 100 μg/mL indicating their safety. These results enrich the known chemistry of V. amygdalina and support its use in folk medicine for the treatment of malaria. This encourages further research towards new antiplasmodial drug candidates from this plant.