Shape Of Red Blood Cells Research Articles

Scheduled dosage regimen by irreversible electroporation of loaded erythrocytes for cancer treatment.

Precise control of cargo release is essential but still a great challenge for any drug delivery system. Irreversible electroporation (IRE), utilizing short high-voltage pulsed electric fields to destabilize the biological membrane, has been recently approved as a non-thermal technique for tumor ablation without destroying the integrity of adjacent collagenous structures. Due to the electro-permeating membrane ability, IRE might also have great potential to realize the controlled drug release in response to various input IRE parameters, which were tested in a red blood cell (RBC) model in this work. According to the mathematical simulation model of a round biconcave disc-like cell based on RBC shape and dielectric characteristics, the permeability and the pore density of the RBC membrane were found to quantitatively depend on the pulse parameters. To further provide solid experimental evidence, indocyanine green (ICG) and doxorubicin (DOX) were both loaded inside RBCs (RBC@DOX&ICG) and the drug release rates were found to be tailorable by microsecond pulsed electric field (μsPEF). In addition, μsPEF could effectively modulate the tumor stroma to augment therapy efficacy by increasing micro-vessel density and permeability, softening extracellular matrix, and alleviating tumor hypoxia. Benefiting from these advantages, this IRE-responsive RBC@DOX&ICG achieved a remarkably synergistic anti-cancer effect by the combination of μsPEF and chemotherapy in the tumor-bearing mice model, with the survival time increasing above 90 days without tumor burden. Given that IRE is easily adaptable to different plasma membrane-based vehicles for delivering diverse drugs, this approach could offer a general applicability for cancer treatment.

Investigating the impact of APOE4 genotype on the association between cerebral blood flow and haematological properties in mid‐life adults

AbstractBackgroundCarriership of the apolipoprotein ε4 (APOE4) allele confers a heightened risk for the development of Alzheimer’s disease (AD). Cerebral blood flow (CBF) is decreased in prodromal and established AD, however findings in the preclinical stage are mixed, with some studies reporting increases. CBF can be impacted by many factors including the haematocrit. We investigated in a cohort at risk of developing AD how haematological variables relate to CBF and if this relationship is differentially moderated by APOE4.Method375 participants from the PREVENT‐Dementia study underwent arterial spin labelling (ASL) and structural 3Tesla MRI. ASL data were analysed using BASIL/FSL and structural scans with SPM12. CBF maps were corrected for partial volume effects. A vascular territory mask with nine territories, the middle, proximal and distal branches of the anterior, middle and posterior cerebral arteries (ACA, MCA, PCA) was used for region‐of‐interest analysis and registered to the native ASL space. Regional gray matter (GM) CBF values were harmonised using COMBAT. Linear regression was used to examine differences between APOE4 carriers and non‐carriers controlling for age, sex and years of education. Associations between haematological properties and CBF were examined with Pearson’s correlations. Differential relationships between CBF, haematocrit, and measures of red blood cell size and shape (distribution width (RDW) and mean corpuscular volume (MCV)) were investigated by including interaction terms of APOE4 and haematological variables in the models.ResultAPOE4 carriers had significantly higher CBF in the proximal MCA (t = 2.54, p = 0.01). Across all subjects, RDW and MCV were not associated with GM CBF, though several significant interactions were observed between APOE4 and RDW in predicting CBF (Figure 1). Haematocrit was associated with GM CBF (ρ = ‐0.19, p < 0.01). No significant interactions were seen between APOE4 and haematocrit or MCV in predicting CBF.ConclusionThe variability of the size and shapes of erythrocytes was differentially associated with CBF between APOE4 carriers and non‐carriers suggesting a different response to morphological erythrocyte alterations. This could further relate to underlying factors such as inflammation, which is associated with a higher RDW. Such associations should be examined in further studies.

Investigating the impact of APOE4 genotype on the association between cerebral blood flow and haematological properties in mid‐life adults

AbstractBackgroundCarriership of the apolipoprotein ε4 (APOE4) allele confers a heightened risk for the development of Alzheimer’s disease (AD). Cerebral blood flow (CBF) is decreased in prodromal and established AD, however findings in the preclinical stage are mixed, with some studies reporting increases. CBF can be impacted by many factors including the haematocrit. We investigated in a cohort at risk of developing AD how haematological variables relate to CBF and if this relationship is differentially moderated by APOE4.Method375 participants from the PREVENT‐Dementia study underwent arterial spin labelling (ASL) and structural 3Tesla MRI. ASL data were analysed using BASIL/FSL and structural scans with SPM12. CBF maps were corrected for partial volume effects. A vascular territory mask with nine territories, the middle, proximal and distal branches of the anterior, middle and posterior cerebral arteries (ACA, MCA, PCA) was used for region‐of‐interest analysis and registered to the native ASL space. Regional gray matter (GM) CBF values were harmonised using COMBAT. Linear regression was used to examine differences between APOE4 carriers and non‐carriers controlling for age, sex and years of education. Associations between haematological properties and CBF were examined with Pearson’s correlations. Differential relationships between CBF, haematocrit, and measures of red blood cell size and shape (distribution width (RDW) and mean corpuscular volume (MCV)) were investigated by including interaction terms of APOE4 and haematological variables in the models.ResultAPOE4 carriers had significantly higher CBF in the proximal MCA (t = 2.54, p = 0.01). Across all subjects, RDW and MCV were not associated with GM CBF, though several significant interactions were observed between APOE4 and RDW in predicting CBF (Figure 1). Haematocrit was associated with GM CBF (ρ = ‐0.19, p < 0.01). No significant interactions were seen between APOE4 and haematocrit or MCV in predicting CBF.ConclusionThe variability of the size and shapes of erythrocytes was differentially associated with CBF between APOE4 carriers and non‐carriers suggesting a different response to morphological erythrocyte alterations. This could further relate to underlying factors such as inflammation, which is associated with a higher RDW. Such associations should be examined in further studies.

Red Blood Cells’ Area Deformation as the Origin of the Photoplethysmography Signal

The origin of the photoplethysmography (PPG) signal is a debatable topic, despite plausible models being addressed. One concern revolves around the correlation between the mechanical waveform’s pulsatile nature and the associated biomechanism. The interface between these domains requires a clear mathematical or physical model that can explain physiological behavior. Describing the correct origin of the recorded optical waveform not only benefits the development of the next generation of biosensors but also defines novel health markers. In this study, the assumption of a pulsatile nature is based on the mechanism of blood microcirculation. At this level, two interconnected phenomena occur: variation in blood flow velocity through the capillary network and red blood cell (RBC) shape deformation. The latter effect was qualitatively investigated in synthetic capillaries to assess the experimental data needed for PPG model development. Erythrocytes passed through 10 µm and 6 µm microchannel widths with imposed velocities between 50 µm/s and 2000 µm/s, according to real scenarios. As a result, the length and area deformation of RBCs followed a logarithmic law function of the achieved traveling speeds. Applying radiometric expertise on top, mechanical-optical insights are obtained regarding PPG’s pulsatile nature. The mathematical equations derived from experimental data correlate microcirculation physiologic with waveform behavior at a high confidence level. The transfer function between the biomechanics and the optical signal is primarily influenced by the vasomotor state, capillary network orientation, concentration, and deformation performance of erythrocytes.

Radiofrequency dielectric spectroscopy study: Effects of pH, hydrogen bond donors and acceptors on the attachment of spectrin skeleton to the lipid membrane of erythrocytes.

Band 3 protein and glycophorin C are the two major integral proteins of the lipid membrane of human red blood cells (RBCs). They are attached from below to a network of elastic filamentous spectrin, the third major RBC membrane protein. The binding properties of the attachments to spectrin affect the shape and deformability of RBCs. We addressed band 3 and glycophorin C attachments to spectrin by measuring the strength of two recently discovered radiofrequency dielectric relaxations, βsp (1.4 MHz) and γ1sp (9 MHz), that are observable as changes in the complex admittance of RBCs in medium. In medium at pH 5.2, and also in media with protic substances (formamide, methylformamide, or urea), the βsp relaxation became inhibited that is attributable to detachment of glycophorin C from spectrin. In medium at pH 9.2, we observed inhibition of γ1sp relaxation attributable to detachment of band 3 from spectrin, as also was seen in media with aprotic substances difluoropyridine, dimethylsolfoxide, dimethylformamide, acetone, sodium tetrakis(4-fluorophenyl)borate), chlorpromazine, thioridazine and trifluopiperazine. The viscogenic cosolvents (glycerol, ethylene glycol, or i-erythritol) inhibited both the βsp and γ1sp relaxations and significantly lowered their characteristic frequencies. Our observations indicate that the glycophorin C attachment to spectrin has nucleophilic centers whose saturation disconnects this attachment and inhibits the βsp relaxation, whereas at band 3-spectrin attachment site, it is the saturation of electrophilic centers that weakens this attachment and inhibits the γ1sp relaxation.

Phosphoproteomics and morphology of stored human red blood cells treated by protein tyrosine phosphatases inhibitor

AbstractThe process of protein phosphorylation is involved in numerous cell functions. In particular, phosphotyrosine (pY) has been reported to play a role in red blood cell (RBC) functions, including the cytoskeleton organization. During their storage before transfusion, RBCs suffer from storage lesions that affect their energy metabolism and morphology. This study investigated the relationship between pY and the storage lesions. To do so, RBCs were treated (in the absence of calcium) with a protein tyrosine phosphatase inhibitor (orthovanadate [OV]) to stimulate phosphorylation and with 3 selective kinase inhibitors (KIs). Erythrocyte membrane proteins were studied by western blot analyses and phosphoproteomics (data are available via ProteomeXchange with identifier PXD039914) and cell morphology by digital holographic microscopy. The increase of pY triggered by OV treatment (inducing a global downregulation of pS and pT) disappeared during the storage. Phosphoproteomic analysis identified 609 phosphoproteins containing 1752 phosphosites, of which 41 pY were upregulated and 2 downregulated by OV. After these phosphorylation processes, the shape of RBCs shifted from discocytes to spherocytes, and the addition of KIs partially inhibited this transition. The KIs modulated either pY or pS and pT via diverse mechanisms related to cell shape, thereby affecting RBC morphology. The capacity of RBCs to maintain their function is central in transfusion medicine, and the presented results contribute to a better understanding of RBC biology.

Lessons Learned from Nanbar Health: Developing a Multi-System Software Suite for Predictive Algorithms and Remote Monitoring for People Living with Sickle Cell Disease

Background: Sickle cell disease (SCD) is a genetic disorder that alters the shape of red blood cells, leading to significant complications and requiring highly complex care. Efforts often focus on prevention and early diagnosis of pain to improve outcomes for those with SCD. Remote monitoring (RPM) and predictive algorithms has grown exponentially in the last decade as a support tool for managing chronic diseases like heart failure and diabetes. Implementing similar technology for SCD care could improve patient outcomes through early detection of complications and providing physicians with longitudinal data to support clinical decisions. Our team previously used mobile health (mHealth) as RPM in this population and developed a machine learning algorithm to predict pain scores with 86% accuracy. Here, we describe the development process for the Nanbar Health software alongside the lessons learned from its development. Objectives: Describe the methods necessary to build a comprehensive mHealth remote monitoring system (Nanbar Health) that facilitates SCD health management. Develop a set of lessons for other developers when building a remote monitoring software suite. Methods: Nanbar Health's development process has taken 2 years. First, our team reviewed feedback and “bug” reports from patients and providers of other mobile applications our team built at Duke University. Using the feedback collected an user-interface (UI) interface (mock-ups) was created for the Nanbar Health mobile app using Figma. These mock-ups were then shown to healthcare providers with expertise in caring for individuals with SCD for feedback. Upon approval of mock-ups, our team developed the mobile application using Swift and Apple HealthKit. The team also built a physician-facing dashboard using React, NodeJS, and Python. The backend software for this system utilized Docker containers mounted on AWS EC2 instances, a Parse server, MongoDB and PostgreSQL databases, and Nginx for deployment and load balancing. Next, the dashboard was reviewed by medical providers for feedback. The analytics portion of the dashboard processed data in Python backend scripts and interactive visualizations were built using the Plotly library in NodeJS. The analytics portion of the tool is currently being reviewed for feedback. Throughout the process of developing and piloting the Nanbar Health Software, our team identified several challenges. These challenges were collected into a comprehensive index named, “Lessons Learned”. Results: The lessons learned include: 1. Overall Gain user feedback and place yourself in the shoes of the user: At every step of your software's development ensure you are continuously getting feedback from your users. 2. Mobile Application Engagement is key to acquiring good data: Ensure your team uses a variety of methods methods to engage your users.No mobile app is one size fits all, but one app can customize to all: The development team should create re-usable, dynamic components wherever possible. 3. Provider Dashboard Testing to build: Developers should build a user interface that is easy to run and test as a “pseudo-user” while they are building it, making it easier for the developer to understand the user experience and build a user-friendly application.Building to test: Plan for beta testers from the beginning and ensure that they have access to continuously-updated and fake but realistic data. 4. Network Analysis Complex analytics are computationally demanding - Advanced analytical tools incur more complications when incorporated into a High-Usage SystemFor heavy data processing, go serverless - Isolating heavy data processing from the rest of the application saves tremendous time and money. 5. Research and Operations Don't cry over spilt code: Mistakes and bugs are part of the process when developing any software, and part of the research process.Lack of engagement is not a reason for disappointment, but rather an opportunity for growth and improvement: Our tool has continuously experienced changes and improvements to increase patient engagement. Conclusion: Our team was successfully able to create and deploy a SCD care-focused Nanbar Health. These tools show promise of improving care for people living with SCD through the usage of RPM and predictive models. Further research should be conducted to determine methods to increase user engagement, and maintain large predictive models in cloud-based systems.

Associations between Sickle Cell Disease, Pica and Enuresis

Introduction: Sickle cell disease (SCD) is a genetic disorder that impacts the shape and functional capacity of red blood cells. Beyond altered cerebral perfusion, individuals with SCD have higher rates of neurodevelopmental disorders (NDDs), including attention deficit hyperactivity disorder (ADHD), intellectual disability, and specific learning disabilities. Past research has shown that in adolescent populations with either SCD or NDDs, pica, the act of eating non-food items, and enuresis, or involuntary urination, commonly occur. Both pica and enuresis are associated with biopsychosocial issues in typically developing children. However, the etiology of both of these disorders, as well as the confluence of NDDs and SCD on their occurrence, remains unclear. Hypothesis: The objective of this study was to determine the rates of pica and enuresis in a local pediatric SCD clinic and determine if these conditions present differently and/or have different associations in SCD than in the general population. We hypothesized that NDDs would serve as risk factors for both pica and enuresis with both conditions being associated with increased sickle cell severity. Methods: To test these hypotheses, we performed a retrospective chart review on 275 SCD patients. Using Epic, patients who at point visited either Kennedy Krieger Institute or John Hopkins Medical Center for SCD and were in an existing database were queried. Patients in the database ranged from 1 to 17 years old and were predominantly Black, non-Hispanic individuals. Primary keywords searched included: “enuresis, pica, bedwetting, diurnal, nocturnal, eating, non-food, peeing, urination, incontinence.” Results: Pica was reported in 9% (Table 1), while enuresis was reported in 27% of patient charts reviewed (Table 2). Both enuresis (Chi-squared test, p = 0.0050) and pica (Chi-squared test, p = 0.0190) were significantly linked to NDD occurrence, with pica being nearly three times as likely to occur alongside NDDs and/or enuresis. Notably, SCD patients with pica most commonly ate paper or wood, different from the general population with pica primarily eating rocks or dirt. Through the Wilcoxon rank sum test, we also noted no associations between pica and median hemoglobin (p=0.9572), ferritin (p=0.6209), iron serum (p=0.9500), total iron-binding capacity (p=0.1598), iron saturation (p=0.6292), or transferrin (p=0.1765) levels. Beyond this, our data also validate prior results demonstrating that enuresis is associated with both SCD type and hydroxyurea usage. There were no significant differences in rates of enuresis between males and females, unlike what is seen in the general population. Sleep apnea was associated with enuresis, at a higher rate than in the general population (Chi-squared post-hoc residual test, p = 0.0004). Patients with SCD and enuresis had higher mean reticulocyte counts and lower mean hemoglobin levels than patients with SCD without enuresis, consistent with increased hemolysis and worsening SCD severity. Conclusion: These results suggest etiologies for pica and enuresis in SCD patients may differ from the general population. As pica and enuresis commonly occur together with NDDs, there is a clear need for increased standardized screening for these conditions in clinics. Understanding why the risk factors for these conditions in SCD differ from the general population requires further investigation into their respective mechanisms of disease.

Numerical analysis of oxygen uptake processes by red blood cells in stopped-flow measurements: Effects of cell shape, membrane permeability and unstirred layer

The transport process of oxygen and other gas species across red blood cell (RBC) membrane is of great importance for better understanding the critical biological functions of RBCs, and the stopped-flow experiments have often been employed for such investigations. In previous stopped-flow analyses, the RBC had usually been represented by a spherical capsule based on the RBC volume, and an assumed unstirred layer (USL) thickness had been used to determine the membrane permeability. In this research, unlike these previous studies, we simulate the oxygen uptake process with different RBC shapes (shperical, ellipsoidal and biconcave) and examine the effects of USL thickness and membrane permeability over broad ranges based on literature values. Our results show that the excess membrane area can greatly improve the oxygen transport efficiency, and a same uptake half-time can be obtained using different combinations of USL thickness and membrane permeability. These findings raise concerns on the reliability and uncertainty for the results and conclusions in previous studies, and also call for more complete numerical models, for example, with the fluid flow and cell deformation considered, and more in-depth investigations on the oxygen transport processes.

MRI Directed Magnevist Effective to Study Toxicity of Gd-Doped Mesoporous Carbon Nanoparticles in Mice Model.

Magnetic resonance imaging (MRI) has been a valuable and widely used examination technique in clinical diagnosis and prognostic efficacy evaluation. The introduction of MRI contrast agent (CA) improves its sensitivity obviously, particularly with the development of nano-CA, which presents higher contrast enhancement ability. However, systematical evaluation of their toxicity is still limited, hampering their further translation in clinics. In this paper, to systematically evaluate the toxicity of nano-CA, Gd-doped mesoporous carbon nanoparticles (Gd-MCNs) prepared by a one-step hard template method were introduced as a model and clinically used MRI CA, Magnevist (Gd-DTPA) as control. Their in vitro blood compatibility, cellular toxicity, DNA damage, oxidative stress, inflammation response as well as in vivo toxicity and MR imaging behaviors were studied and compared. The experimental results showed that compared with Gd-DTPA, Gd-MCNs displayed negligible influence on the red blood cell shape, aggregation, BSA structure, macrophage morphology and mitochondrial function. Meanwhile, limited ROS and inflammatory cytokine production also illustrated the cellular compatibility of Gd-MCNs. For in vivo toxicity evaluation, Gd-MCNs presented acceptable in vivo biosafety even under 12 times injection for 12 weeks. More importantly, at the same concentration of Gd, Gd-MCNs displayed better contrast enhancement of tumor than Gd-DTPA, mainly coming from its high MRI relaxation rate which is nearly 9 times that of Gd-DTPA. In this paper, we focus on the toxicity evaluation of MRI nano-CA, Gd-MCNs from different angles. With Gd-DTPA as control, Gd-MCNs appeared to be highly biocompatible and safe nanoparticles that possessed promising potentials for the use of MRI nano-CA. In the future, more research on the long-term genotoxicity and the fate of nanoparticles after being swallowed should be performed.

An Exploration of the Effects of Gene-Editing Technology on Human Identity

An Exploration of the Effects of Gene-Editing Technology on Human Identity

Production of Feline Universal Erythrocytes with Methoxy Polyethylene Glycol.

Blood group mismatch in veterinary medicine is a significant problem in blood transfusion, sometimes leading to severe transfusion reactions and even patient death. Blood groups vary from species to species and there are three known blood groups in cats: A, B and AB. While A-type cats are most common, there is a shortage of feline B-type blood groups in cats. By using methoxy polyethylene glycol (mPEG) to protect antigenic epitopes on red blood cells (RBCs), we aimed to find the optimal conditions for the production of feline universal RBCs. The surfaces of feline A-type RBCs were treated with mPEG at various molecular weights and concentrations. Agglutination tests showed that the coating of feline A-type RBCs with mPEG of 20 kDa and 2 mM blocked hemagglutination to feline anti-A alloantibodies over 8 h. While no differences in RBC size and shape between intact and mPEG-treated RBCs were seen, coating RBCs with mPEG inhibited the binding of feline anti-A alloantibodies. Furthermore, the mPEG-treated RBCs did not cause spontaneous hemolysis or osmotic fragility, compared to control RBCs. According to a monocyte monolayer assay, mPEG treatment significantly reduced feline anti-A antibody-mediated phagocystosis of RBCs. These results confirm the potential of using activated mPEG on feline A-type RBC to create universal erythrocytes for transfusion to B-type cats.

The Cytotoxic Effect of Septic Plasma on Healthy RBCs: Is Eryptosis a New Mechanism for Sepsis?

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

The Effect of Synthetic Polycation Poly-2-Dimethylaminoethylmethacrylate on Biological Activity of Mammalian Resident and Nonresident Cells

Cationic polymers are the positively charged macromolecules that have in their structure N-containing functional groups such as primary, secondary and tertiary amine groups; quaternary ammonium groups and others. The effect of synthetic polycation poly-2-dimethylaminoethylmethacrylate (PDMAEM) on biological activity of animal fibroblasts (CHL V-79 RJK) and human red blood cells (RBCs) was studied. The influence of PDMAEM on cell adhesion using fibroblast culture was analyzed. Cultural plastic treated or untreated by polycation was used as substrate. The polycation adsorption on polystyrene surface did not change the adhesive capacity of fibroblasts. Pretreatment of fibroblasts with PDMAEM did not influence at low concentrations (0.1 and 1 μg/mL) the adhesive properties of cells plated on the untreated plastic surface. At high concentrations (10 and 100 μg/mL) PDMAEM inhibited the attachment of fibroblasts to this substrate. Relationship between the inhibition of cell adhesion under PDMAEM action and the toxic effect on fibroblast viability has been found. The PDMAEM treatment of human RBCs at high doses led to the damage of cells and release of hemoglobin to incubation medium. At low doses PDMAEM practically did not influence the hemolysis of RBCs. It was shown that PDMAEM induced the change of the shape and aggregation of RBCs. The toxic effect of PDMAEM on human RBCs coincided as a whole with such effect for animal fibroblasts. Possible cell targets upon the PDMAEM effect are discussed.

Yoga Module Development and Validation for Sickle Cell Disease.

Sickle cell disease (SCD) is a genetic blood disorder that affects the shape and function of red blood cells (RBCs), which can lead to several health problems affecting the quality of life. SCD can be treated with certain expensive treatments such as RBC transfusion, hydroxyurea, stem cell transplantation, gene therapy, or bone marrow transplant. However, some of the most common symptoms such as pain, anxiety, and stress can also be alleviated with alternative therapies like yoga. In light of this, there is a need for the development of a specific yoga module (YM) for SCD that can complement the current therapies. To develop and validate a YM for SCD. Concise literature reports on yoga practices used for varied symptoms/comorbidities associated with SCD were compiled and presented to focus groups. Based on the presented report and personal experience, the focus group created a preliminary version of the module. The preliminary module was further refined based on content validity ratio (CVR) following module validation by 33 yoga experts. One hour ten minutes module developed by the focus group had in total 27 practices including, loosening exercises, asanas, pranayama, relaxation techniques, and meditation. After validation by the experts, 21 practices with a CVR ≥ 0.33 were retained. The predominant reason for excluding 12 practices was intensity, which may have some adverse effect on sickle cell comorbidities. The module developed is the first validated module for SCD.

Computational investigation of flow dynamics and mechanical retention of age-associated red blood cells in the spleen

The shape and deformability of red blood cells (RBCs) change with age, increasing their likelihood of becoming trapped in the splenic interendothelial slits (IESs) and being removed from the circulation. Existing evidence suggests that cell size and viscoelasticity vary with age, which impedes understanding of the mechanical retention of aged RBCs in the spleen. We present a computational study of the flow dynamics, shape changes, and mechanical retention of age-associated RBCs in the splenic IES. The results show that increasing RBC membrane viscosity slows the flow process early in aging, while increased sphericity due to cell size reduction eventually leads to RBC retention.

The effects of non-functionalized polystyrene nanoparticles with different diameters on human erythrocyte membrane and morphology

In this study, the potential toxicity of non-functionalized polystyrene nanoparticles (PS-NPs) in human erythrocytes has been assessed. The effect of PS-NPs with different diameters (∼30 nm, ∼45 nm, ∼70 nm) on fluidity of erythrocytes membrane, red blood cells shape, as well as haemolysis of these cells has been investigated. Erythrocytes were incubated for 24 h with non-functionalized PS-NPs in concentrations ranging from 0.001 to 200 μg/mL in order to study haemolysis and from 0.001 to 10 μg/mL to determine other parameters. Fluidity was estimated by electron paramagnetic resonance (EPR) and the fluorimetric method. It has been shown that PS-NPs induced haemolysis, caused changes in the fluidity of red blood cells membrane, and altered their shape. Non-functionalized PS-NPs increased the membrane stiffness in the hydrophobic region of hydrocarbon chains of fatty acids. The observed changes in haemolysis and morphology were dependent on the size of the nanoparticles. The smallest PS-NPs of ∼30 nm (with the smallest absolute value of the negative zeta potential −29.68 mV) induced the greatest haemolysis, while the largest PS-NPs of ∼70 nm (with the highest absolute value of the negative zeta potential −42.00 mV) caused the greatest changes in erythrocyte shape and stomatocytes formation.

Analysis of the Polyphenolic Composition of Vaccinium L. Extracts and Their Protective Effect on Red Blood Cell Membranes

The blueberry fruit of the genus Vaccinium, including high blueberry, low blueberry, and wild bilberry, is consumed for its flavor and medicinal properties. The purpose of the experiments was to investigate the protective effect and mechanism of the interaction of blueberry fruit polyphenol extracts with the erythrocytes and their membranes. The content of polyphenolic compounds in the extracts was determined using the chromatographic UPLC–ESI–MS method. The effects of the extracts on red blood cell shape changes, hemolysis and osmotic resistance were examined. Changes in the order of packing and fluidity of the erythrocyte membrane and the lipid membrane model caused by the extracts were identified using fluorimetric methods. Erythrocyte membrane oxidation was induced by two agents: AAPH compound and UVC radiation. The results show that the tested extracts are a rich source of low molecular weight polyphenols that bind to the polar groups of the erythrocyte membrane, changing the properties of its hydrophilic area. However, they practically do not penetrate the hydrophobic part of the membrane and do not damage its structure. Research results suggest that the components of the extracts can defend the organism against oxidative stress if they are delivered to the organism in the form of dietary supplements.

Effect of Cell Age and Membrane Rigidity on Red Blood Cell Shape in Capillary Flow.

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

Abstract 476: Negligible Impacts Of Anesthesia On The Morphodynamics Of Individual Red Blood Cells What Is Good News For Vessels: A Study Exploiting Holotomography

Rationale: The shape and membrane dynamics of individual red blood cells (RBCs) are known to play a significant role in their functionality. The morphodynamics of RBCs optimizes their flow properties in vessels and capillaries, which is important for the balance and optimal distribution of blood and nutrients to the tissues. It is also crucial in pathological contexts because changes can influence vascular and microvascular hemodynamics. It can dysregulate vascular function through the modulation of oxygen delivery and the scavenging and generation of nitric oxide. Therefore, the ideal conditions of RBCs are essential for healthy vascular function. Anesthetics, sedatives, analgesics, and fluids used during anesthesia can impact RBCs. The same applies to pneumoperitoneum performed in laparoscopic procedures. Objectives: Taking above we aimed to prospectively evaluate the influence of anesthesia on RBC volume (CV, fL), surface area (SA, μm2), sphericity (SI), dry mass (CH, pg), Hb concentration (CHC, g/dL) and membrane fluctuation (nm). Methods: We exanimated RBCs (n=760) from 5 female dogs undergoing laparoscopic-assisted ovariohysterectomy (OVH). The blood was collected 15 min after premedication with medetomidine and 1h after full anesthesia (isoflurane, fentanyl). Measurements of RBC parameters we performed using the non-invasive, label-free method of imaging with holotomography. Statistical significance was determined using Mann-Whitney test. Results: Morphodynamics parameter values during anesthesia were stable. We observe statistically no significant changes for RBC parameters after premedication vs. one hour of full anesthesia: CH 24.20 vs. 24,19, p=0.57; CV 59.17 vs. 59.04, p=0.89; CHC 42.33 vs. 41.53, p=0.60; SA 117.38 vs. 119.56, p=0.13; SI 0.63 vs. 0.62, p=0.31; fluctuation 68.18 vs. 65.18, p=0.95. Conclusions: Procedures related to OVH are not reflected in the parameters of RBCs and their well-being. This provides new insight into the impact and safety of the anesthetic protocol used in this study on blood cell function, which translates into the lack of risk of vascular damage.