Predictive value of red blood cell distribution width and hematocrit for short-term outcomes and prognosis in colorectal cancer patients undergoing radical surgery

BACKGROUND Previous studies have reported that low hematocrit levels indicate poor survival in patients with ovarian cancer and cervical cancer,the prognostic value of hematocrit for colorectal cancer(CRC)patients has not been determined.The prognostic value of red blood cell distribution width(RDW)for CRC patients was controversial.AIM To investigate the impact of RDW and hematocrit on the short-term outcomes and long-term prognosis of CRC patients who underwent radical surgery.METHODS Patients who were diagnosed with CRC and underwent radical CRC resection between January 2011 and January 2020 at a single clinical center were included.The short-term outcomes,overall survival(OS)and disease-free survival(DFS)were compared among the different groups.Cox analysis was also conducted to identify independent risk factors for OS and DFS.RESULTS There were 4258 CRC patients who underwent radical surgery included in our study.A total of 1573 patients were in the lower RDW group and 2685 patients were in the higher RDW group.There were 2166 and 2092 patients in the higher hematocrit group and lower hematocrit group,respectively.Patients in the higher RDW group had more intraoperative blood loss(P<0.01)and more overall complications(P<0.01)than did those in the lower RDW group.Similarly,patients in the lower hematocrit group had more intraoperative blood loss(P=0.012),longer hospital stay(P=0.016)and overall complications(P<0.01)than did those in the higher hematocrit group.The higher RDW group had a worse OS and DFS than did the lower RDW group for tumor node metastasis(TNM)stage I(OS,P<0.05;DFS,P=0.001)and stage II(OS,P=0.004;DFS,P=0.01)than the lower RDW group;the lower hematocrit group had worse OS and DFS for TNM stage II(OS,P<0.05;DFS,P=0.001)and stage III(OS,P=0.001;DFS,P=0.001)than did the higher hematocrit group.Preoperative hematocrit was an independent risk factor for OS[P=0.017,hazard ratio(HR)=1.256,95%confidence interval(CI):1.041-1.515]and DFS(P=0.035,HR=1.194,95%CI:1.013-1.408).CONCLUSION A higher preoperative RDW and lower hematocrit were associated with more postoperative complications.However,only hematocrit was an independent risk factor for OS and DFS in CRC patients who underwent radical surgery,while RDW was not.

Effect of sodium nitroprusside on the microrheological properties of red blood cells in different media

Red blood cell(RBC)aggregation as well as their deformation significantly affects blood microrheology.These processes depend on various factors,one of which is concentration of the nitric oxide,one of the main signaling molecule in the bloodstream.The purpose of this study was to investigate the effect of nitric oxide on the microrheological properties of red blood cells(RBCs)in RBC samples of various media after the addition of nitric oxide donor sodium nitroprusside in vitro.Microrheological properties were measured using laser aggregometer and ektacytometer based on diffuse light scattering and diffraction of laser light on a suspension of RBCs,respectively.The study found that heparin-stabilized blood showed increased RBC aggregation and deformation with sodium nitroprusside concentrations of 100,and 200M,while EDTA-stabilized blood showed slightly decreased aggregation and unchanged deformation.With washed RBCs in dextran solution,the addition of sodium nitroprusside(in the concentrations of 100,and 200M)resulted in decreased aggregation and increased deformation.These-ndings aid in our understanding of nitric oxide's effect on RBC microrheological properties.

Using Optical Tweezers to Study the Friction of the Red Blood Cells

In the last two decades the study of red blood cell elasticity using optical tweezers has known a rise appearing in the scientific research with regard to the various works carried out. Despite the various work done, no study has been done so far to study the influence of friction on the red blood cell indentation response using optical tweezers. In this study, we have developed a new approach to determine the coefficient of friction as well as the frictional forces of the red blood cell. This approach therefore allowed us to simultaneously carry out the indentation and traction test, which allowed us to extract the interfacial properties of the microbead red blood cell couple, among other things, the friction coefficient. This property would be extremely important to investigate the survival and mechanical features of cells, which will be of great physiological and pathological significance. But taking into account the hypothesis of friction as defined by the isotropic Coulomb law. The experiment performed for this purpose is the Brinell Hardness Test (DB).

Application of neutrophil-lymphocyte ratio and red blood cell distribution width in diabetes mellitus complicated with heart failure

BACKGROUND Accumulating clinical evidence has shown that diabetes mellitus(DM)is a serious risk factor for cardiovascular disorders and an important factor for adverse cardiovascular events.AIM To explore the value of the combined determination of the neutrophil-lymphocyte ratio(NLR)and red blood cell distribution width(RDW)in the early diagnosis and prognosis evaluation of DM complicated with heart failure(HF).METHODS We retrospectively analyzed clinical data on 65 patients with type 2 DM(T2DM)complicated with HF(research group,Res)and 60 concurrent patients with uncomplicated T2DM(control group,Con)diagnosed at Zhejiang Provincial People’s Hospital between January 2019 and December 2021.The NLR and RDW values were determined and comparatively analyzed,and their levels in T2DM+HF patients with different cardiac function grades were recorded.The receiver operating characteristic(ROC)curves were plotted to determine the NLR and RDW values(alone and in combination)for the early diagnosis of HF.The correlation between NLR and RDW with the presence or absence of cardiac events was also investigated.RESULTS Higher NLR and RDW levels were identified in the Res vs the Con groups(P<0.05).The NLR and RDW increased gradually and synchronously with the deterioration of cardiac function in the Res group,with marked differences in their levels among patients with grade II,III,and IV HF(P<0.05).ROC curve analysis revealed that NLR combined with RDW detection had an area under the curve of 0.915,a sensitivity of 76.9%,and a specificity of 100%for the early diagnosis of HF.Furthermore,HF patients with cardiac events showed higher NLR and RDW values compared with HF patients without cardiac events.CONCLUSION NLR and RDW were useful laboratory indicators for the early diagnosis of DM complicated with HF,and their joint detection was beneficial for improving diagnostic efficiency.Additionally,NLR and RDW values were directly proportional to patient outcomes.

Development of Non-ABO Red Blood Cell Alloantibodies in Patient Undergoing Allogeneic Haematopoietic Stem Cell Transplant

Alloantibodies that are non ABO Alloimmunization to protein antigens happens only after exposure, in contrast to ABO isohaemagglutinins, which are present naturally, even in the absence of prior exposure. It is recognized that while non-ABO RBC antibodies are less common than ABO antibodies, they generate essentially the same issues that lead to unfavorable clinical results. If non-ABO alloantibodies are identified early on, these issues related complications may be avoided This call for an in-depth understanding of the recipient and donor’s ABO-Rh grouping, antibody screening, and the phenotype of certain antigens. Equally important, the temporal association time between transplantation and hemolysis can help identify the underlying mechanism of hemolysis and direct appropriate management. Therefore, for that, it is crucial to identify the etiology of post-HSCT anemia for prevention and therapy, in addition to a thorough grasp of the mechanism of anemia in non-ABO-incompatible HSCT and the temporal link between HSCT and anemia. Finding the cause of post-HSCT anemia is essential for prevention and therapy, in addition to a thorough grasp of the mechanism of anemia in non-ABO-incompatible HSCT and the temporal link between HSCT and anemia. Therefore, for that, it is crucial to identify the etiology of post-HSCT anemia. In this case report review, we would like to highlight the vital role of transfusion medicine services and stem cell clinical teams in paying particular attention to the clinical significance of non-ABO alloantibodies involved to avoid causing overt hemolysis of incompatible donor RBCs or delayed erythropoiesis. Considering the fact that some of the Haematopoietic stem cell transplant centers do not give an attention to the other non-ABO RBC antigens.

Antioxidative Effect of Schiff Bases with o-Hydroxybenzylidene Groupon Free Radical Induced Hemolysis of Human Red Blood Cell

The hemolysis of human red blood cells was initiated by a water soluble free radical initiator, 2,2′ azobis (2 amidinopropane hydrochloride)(AAPH), at 37 ℃ in phosphate buffered saline(pH=7.4). The respective addition of 1 [ N (o hydroxybenzylidene)amino]tetradecane(TDCA), 1,2 di[ N (o hydroxybenzylidene)amino]cyclohexane(DACH), 4 [ N (o hydroxybenzylidene)amino]benzoic acid(PABA), 4 nitro[ N (o hydroxybenzylidene)]aniline(APNA) or N (o hydroxybenzylidene)aniline(APA) can all prolong the inhibition period of hemolysis, indicating that the above Schiff bases play an antioxidative role in free radical induced hemolysis. It can be concluded that Schiff base with an alkyl group or a conjugated system in the molecule protect red blood cells against free radical induced hemolysis efficiently. This information may be useful for antioxidant drug design.

EFFECT OF ELECTROACUPUNCTURE ON RED BLOOD CELL IMMUNE AND T-CELL SUBGROUP IN THE RAT

In the present study, the effect of electroacupuncture (EA) on immune system was observed in the rat by using micro- whole blood direct immunofluorescence staining assay to detect changes of the peripheral blood T lymphocyte subgroup and employing red blood cell (RBC) C 3b receptor- yeast rosette test and red blood cell-IC rosette test to analyze erythrocytic immune function. Results showed that after EA of “Zusanli" (ST 36), CD+ 4, RBC-C 3bRR and RBC-ICR in the peripheral blood of the normal rats increased significantly while CD+ 8 had no any considerable changes and a positive correlation between CD+ 4 and RBC-C 3bRR was found. In immunosuppression model rats, the values of CD+ 4 and RBC-C 3bRR were obviously lower than those of the normal control group while CD+ 8 had no any striking changes; but after EA treatment, there were no evident differences between EA group and normal control group in the above-mentioned indexes. There were also no any significant differences between non-acupoint group and normal control group in those indexes. Results suggest that EA of “Zusanli" (ST 36) can raise T cell immune function and RBC adhesion function in both normal rats and immunosuppression model rats, both of which present a positive correlation.

Prognostic value of red blood cell distribution width for severe acute pancreatitis

BACKGROUND Severe acute pancreatitis(SAP)is a common condition in the intensive care unit(ICU)and has a high mortality.Early evaluation of the severity and prognosis is very important for SAP therapy.Recently,red blood cell distribution(RDW)was associated with mortality of sepsis patients and could be used as a predictor of prognosis.Similarly,RDW may be associated with the prognosis of SAP patients and be used as a prognostic indicator for SAP patients.AIM To investigate the prognostic value of RDW for SAP patients.METHODS We retrospectively enrolled SAP patients admitted to the ICU of the First Affiliated Hospital of China Medical University from June 2015 to June 2017.According to the prognosis at 90 d,SAP patients were divided into a survival group and a non-survival group.RDW was extracted from a routine blood test.Demographic parameters and RDW were recorded and compared between the two groups.The receiver operator characteristic(ROC)curve was constructed and Cox regression analysis was performed to investigate the prognostic value of RDW for SAP patients.RESULTS In this retrospective cohort study,42 SAP patients were enrolled,of whom 22 survived(survival group)and 20 died(non-survival group).The baseline parameters were comparable between the two groups.The coefficient of variation of RDW(RDW-CV),standard deviation of RDW(RDW-SD),Acute Physiology and Chronic Health Evaluation II(APACHE II)score,and Sequential Organ Failure Assessment(SOFA)score were significantly higher in the non-survival group than in the survival group(P<0.05).The RDW-CV and RDW-SD were significantly correlated with the APACHE II score and SOFA score,respectively.The areas under the ROC curves(AUCs)of RDW-CV and RDW-SD were all greater than those of the APACHE II score and SOFA score,among which,the AUC of RDW-SD was the greatest.The results demonstrated that RDW had better prognostic value for predicting the mortality of SAP patients.When the RDW-SD was greater than 45.5,the sensitivity for predicting prognosis was 77.8%and the specificity was 70.8%.Both RDW-CV and RDW-SD could be used as independent risk factors to predict the mortality of SAP patients in multivariate logistic regression analysis and univariate Cox proportional hazards regression analysis,similar to the APACHE II and SOFA scores.CONCLUSION The RDW is greater in the non-surviving SAP patients than in the surviving patients.RDW is significantly correlated with the APACHE II and SOFA scores.RDW has better prognostic value for SAP patients than the APACHE II and SOFA scores and could easily be used by clinicians for the treatment of SAP patients.

Prognostic significance of red blood cell distribution width in gastrointestinal disorders

The red blood cell distribution width(RDW) is a routinely measured and automatically reported blood parameter,which reflects the degree of anisocytosis. Recently,the baseline RDW was found to have clinical significance for assessing clinical outcome and severity of various pathological conditions including cardiovascular diseases,sepsis,cancers,leukemia,renal dysfunction and respiratory diseases. A myriad of factors,most of which ill-defined,have an impact on the red cell population dynamics(i.e.,production,maturation and turnover). A delay in the red blood cell clearance in pathological conditions represents one of the leading determinants of increased anisocytosis. Further study of RDW may reveal new insight into inflammation mechanisms. In this review,we specifically discuss the current literature about the association of RDW in various disease conditions involving the gastrointestinal and hepatobiliary systems. We also present some of the related measurements for their value in predicting clinical outcomes in such conditions. According to our data,RDW was found to be a valuable prognostic index in gastrointestinal disorders along with additional inflammatory biomarkers(i.e.,C reactive protein,erythrocyte sedimentation rate,and platelet count) and current disease severity indices used in clinical practice.

Red blood cell distribution width: A marker of anisocytosis potentially associated with atrial fibrillation

The incorporation of biomarkers in the actually used risk scores seem to be helpful for early identifying atrial fibrillation(AF)patients at higher risk.The aim of this critical review of the scientific literature is to investigate the potential clinical significance of red blood cell distribution width(RDW)in AF.A systematic electronic search was carried out to identify all articles describing an epidemiological association between RDW and AF in adult human populations.Data abstraction was conducted on a final number of 35 articles(13 crosssectional,12 prospective and 10 retrospective studies).The results of these epidemiological investigations were all virtually concordant to emphasize that an enhanced RDW value is not only a predictive factor and a marker of AF but its measurement may also be helpful for predicting the risk of developing many adverse complications in patients with AF,such as recurrence and duration of AF,hospitalization for heart failure,bleeding,left atrial thrombosis and stasis,thromboembolic events and mortality.AF patients with RDW values exceeding the local reference range may be more aggressively investigated and managed,in order to identify and attenuate the impact of possible underlying disorders causing both anisocytosis and AF.

The Popularization and Application of Cold Storage Red Blood Cells or Whole Blood at -80 ℃ of the Rh(D) Negative Patients in Surgical Operation

Summary: The efficiency of cold storage red blood cells (CSRBC) or whole blood at -80 ℃ used in 27 Rh(D) negative patients during surgical operation was reported. The Rh(D) negative patients received the transfusion of CSRBC or whole blood stored at -80 ℃ for 180 to 360 days. The changes in the indexes, such as blood TB, DB, K +, Na +, BUN, Cr, urine protein (URPO), UOB, Hb, HCT, serum total protein, relative to hemolytic reaction and blood volume before and after transfusion were observed. The results showed that after transfusion of CSRBC or whole blood 27 cases were negative for urine protein and UOB, and the levels of BUN and Cr were normal (P>0.05). Blood TB, DB, Hb, and HCT were increased, while pH, blood K + and blood Na + was normal with the difference being not significant before and after operation (P>0.05). Plasma protein was decreased, but there was no significant difference before and after operation (P>0.05). It was suggested that CSRBC or whole blood at -80 ℃ could be safely infused to the Rh(D) negative patients without side effects during the surgical operation.

Normal Reference Value of Red Blood Cell Count of Chinese Presenile Men and Geographical Factors

This paper aims at providing a scientific basis for unifying the normal reference value standards of red blood cell count of Chinese presenile men. The paper, using microscopical counting method, studies the relationship between the normal reference values of 38,061 samples of red blood cell count of presenile men and eight geographical factors in 297 units in China. It is found that the correlation of geographical factors and the normal reference value of red blood cell count of presenile men is quite significant （F=303.00, P=-0.000）. By using the method of stepwise regression analysis, one regression equation is inferred. It is concluded that if geographical data are obtained in a certain area, the normal reference value of red blood cell count of presenile men in this area can be reckoned by using the regression analysis. Furthermore, according to the geographical factors, China can be divided into eight regions： Northeast China Region, North China Region, Shanxi-Shaanxi-Irmer Mongolia Region, Middle and Lower Reaches of the Changjiang River Region, Southeast China Region, Northwest China Region, Southwest China Region and Qinghai-Tibet Plateau Region.

Study on the packed volume and the void ratio of idealized human red blood cells using a ?nite-discrete element method

Numerical simulations are performed to examine the packing behavior of human red blood cells(RBCs). A combined ?nite-discrete element method(FDEM) is utilized, in which the RBCs are modeled as no-friction and no-adhesion solid bodies. The packed volume and the void ratio of a large number of randomly packed RBCs are clari?ed,and the effects of the RBC shape, the mesh size, the cell number, and the container size are investigated. The results show that the packed human RBCs with normal shape have a void ratio of 28.45%, which is slightly higher than that of the ?at or thick cells used in this study. Such information is bene?cial to the further understanding on the geometric features of human RBCs and the research on RBC simulations.

Isolation of Fetal Nucleated Red Blood Cells from Maternal Blood

To find a simple, effective method of isolating fetal cells from maternal peripheral blood for prenatal diagnosis, 45 women were studied with their gestation being 6-14 weeks and age 21- 30 years. The fetal cells were isolated from maternal blood by using discontinuous density gradient centrifugation. Some of the isolated cells were made smear and counted under the microscope; others were used for predicting fetal sex by PCR amplification of Y chromosome specific DYZ1 gene. The major cells in the upper separation interface were lymphocytes and monocytes, with occasionally seen nucleated red blood cells (NRBC); while those in the middle separation interface were neutrocytes, with NRBC scattering. The ratio of NRBC/nucleated cells was 1. 98±0. 28× 10-5. There was no significant difference between the first and second trimester (P>0. 05). The amount of isolated fetal cells was sufficient for prenatal genetic diagnosis. Male pregnancy was correctly predicted in 10 out of 13 cases. It is concluded that the method of discontinuous density gradient centrifugation was of considerable importance in the development of non-invasive prenatal genetic diagnosis.

Enrichment of Fetal Nucleated Red Blood Cells by Multi-core Magnetic Composite Particles for Non-invasive Prenatal Diagnosis

A novel kind of multi-core magnetic composite particles, the surfaces of which were respectively mo- dified with goat-anti-mouse IgG and antitransferrin receptor（anti-CD71）, was prepared. The fetal nucleated red blood cells（FNRBCs） in the peripheral blood of a gravida were rapidly and effectively enriched and separated by the mo- dified multi-core magnetic composite particles in an external magnetic field. The obtained FNRBCs were used for the identification of the fetal sex by means of fluorescence in situ hybridization（FISH） technique. The results demonstrate that the multi-core magnetic composite particles meet the requirements for the enrichment and speration of FNRBCs with a low concentration and the accuracy of detetion for the diagnosis of fetal sex reached to 95%. Moreover, the obtained FNRBCs were applied to the non-invasive diagnosis of Down syndrome and chromosome 3p21 was de- tected. The above facts indicate that the novel multi-core magnetic composite particles-based method is simple, relia- ble and cost-effective and has opened up vast vistas for the potential application in clinic non-invasive prenatal diag- nosis.

Deformation and Motion of a Red Blood Cell in a Shear Flow Simulated by a Lattice Boltzmann Model

A lattice Boltzmann model is presented to simulate the deformation and motions of a red blood cell （RBC） in a shear flow. The curvatures of the membrane of a static RBC with different chemical potentiM drops calculated by our model agree with those computed by a shooting method very well. Our simulation results show that in a shear flow, biconcave RBC becomes highly flattened and undergoes tank-treading motion. With intrinsically parallel dynamics, this lattice Boltzmann method is expected to find wide applications to both single and multi-vesicles suspension as well as complex open membranes in various fluid flows for a wide range of Reynolds numbers.

Value of red blood cell distribution width in prediction of diastolic dysfunction in cirrhotic cardiomyopathy

BACKGROUND Clinical diagnosis of cirrhotic cardiomyopathy(CCM) often encounters challenges of lack of timeliness and disease severity, with the commonly positive indicator usually associated with advanced heart failure.AIM To explore suitable biomarkers for early CCM prediction.METHODS A total of 505 eligible patients were enrolled in this study and divided into four groups according to Child-Pugh classification: Group Ⅰ, Class A without CCM(105 cases);Group Ⅱ, Class A with CCM(175 cases);Group Ⅲ, Class B with CCM(139 cases);and Group Ⅳ, Class C with CCM(86 cases). Logistic regression and receiver operating characteristic(ROC) curve analyses were performed to determine whether red blood cell distribution width(RDW) was an independent risk factor for CCM risk. The relationships between RDW and Child-Pugh scores, Model for End-Stage Liver Disease(MELD) scores, and N-terminal pro-brain natriuretic peptide(NT-proBNP) were analyzed by Pearson correlation analysis.RESULTS A constant RDW increase was evident from Group Ⅰ to Group Ⅳ(12.54 ± 0.85, 13.29 ± 1.19, 14.30 ± 1.96, and 16.25 ± 2.13, respectively). Pearson correlation analysis showed that RDW was positively correlated with Child-Pugh scores(r = 0.642, P < 0.001), MELD scores(r = 0.592, P < 0.001), and NT-proBNP(r = 0.715, P < 0.001). Furthermore, between Group Ⅰ and Group Ⅱ, RDW was the only significant index(odds ratio: 2.175, 95% confidence interval [CI]: 1.549-3.054, P < 0.001), and it reached statistical significance when examined by ROC curve analysis(area under the curve: 0.686, 95%CI: 0.624-0.748, P < 0.001).CONCLUSION RDW can serve as an effective and accessible clinical indicator for the prediction of diastolic dysfunction in CCM, in which a numerical value of more than 13.05% may indicate an increasing CCM risk.

Evaluation of Red Blood Cell Contribution to Platelet Activation in the Bulk Applying Red Blood Cell—Platelet Thrombus as a Point Source Model

In this study, a point source mathematical model is proposed to describe the diffusion of adenosine di-phosphate (ADP) from either damaged red blood cell (RBC) or activated platelet. The convective diffusion equation is reduced to describe the suggested problem. The final differential equation is solved using Laplace transforms and ADP concentration profiles around the source are obtained. Thrombi of 5 to 20 μm3 containing platelets and a range of red blood cells (RBCs) (0%, 25%, 50%, 75%, 100%) concentrations are used to apply the model. Reported ADP concentrations in the literature are used and its dynamic release from the point source is calculated. Results suggest that RBC chemical contribution to platelet aggregation in the bulk is much less than that of platelet (almost) negligible. However, the physical effect of RBCs is dominant in the bulk through augmentation of released ADP and platelets diffusivities. Moreover, the chemical contribution reported in previous studies is suggested to be as a result of interaction of RBC with the surface under the influence of shear stresses in the boundary region.

Comparison of the conventional tube and erythrocyte-magnetized technology in titration of red blood cell alloantibodies

BACKGROUND Erythrocyte alloantibodies are mainly produced after immune stimulation,such as blood transfusion,pregnancy,and transplantation,and are the leading causes of severe hemolytic transfusion reactions and difficulty in blood grouping and matching.Therefore,antibody screening is critical to prevent and improve red cell alloantibodies.Routine tube assay is the primary detection method of antibody screening.Recently,erythrocyte-magnetized technology(EMT)has been increasingly used in clinical practice.This study intends to probe the application and efficacy of the conventional tube and EMT in red blood cell alloantibody titration to provide a reference for clinical blood transfusion.AIM To investigate the application value of conventional tube and EMT in red blood cell alloantibody titration and enhance the safety of blood transfusion practice.METHODS A total of 1298 blood samples were harvested from blood donors at the Department of Blood Transfusion of our hospital from March 2021 to December 2022.A 5 mL blood sample was collected in tubing,which was then cut,and the whole blood was put into a test tube for centrifugation to separate the serum.Different red blood cell blood group antibody titers were simultaneously detected using the tube polybrene test,tube antiglobulin test(AGT),and EMT screening irregular antibody methods to determine the best test method.RESULTS Simultaneous detection was performed through the tube polybrene test,tube AGT and EMT screening irregular antibodies.It was discovered that the EMT screening irregular antibody method could detect all immunoglobulin G(IgG)and immunoglobulin M(IgM)irregular antibodies,and the results of manual tube AGT were satisfactory,but the operation time was lengthy,and the equipment had a large footprint.The EMT screening irregular antibody assay was also conducted to determine its activity against type O Rh(D)red blood cells,and the outcomes were satisfactory.Furthermore,compared to the conventional tube method,the EMT screening irregular antibody method was more cost-effective and had significantly higher detection efficiency.CONCLUSION With a higher detection rate,the EMT screening irregular antibody method can detect both IgG and IgM irregular antibodies faster and more effectively than the conventional tube method.

The Flow Behavior of Red Blood Cell Reduced Deformability in Microchannel

Blood cells are mainly(~99%)comprised of red blood cells.The most remarkable properties of are their high deformability,which allow they flow through microcapillaries of diameter even smaller than their size.The RBC’s remarkable mechanical properties originate from the unique architecture of its membrane.To study the mechanism of RBC’s deformability,a commonly adopted approach is to localize the cytoskeleton protein by immunofluorescence,followed by exploring the changes of cytoskeleton protein during cell deformation.During this process,the fixed treatment of RBC using GA and PFA is of great importance.However,RBC’s deformability is reduced by the fixation process and skeletal protein of membrane is changed accordingly.The flow behavior of red RBCs through the microchannel also changed.Given the difficulty of observing RBC flow in vivo,in vitro simulation by virtue of microfluidic devices provides a feasible alternative.An important physiological phenomenon of the blood flow is the formation of cell free layer(CFL),with RBCs show a tendency to concentrate towards the central axis of the pipeline and move faster than the plasma layer.However,this phenomena is weaken if the stiffness of the membrane increase,which occurs in some disease,such as hereditary spherocytosis and hereditary elliptocytosis.To study the effects of GA and PFA fix treatment on RBC deformability,a microfluidic platform is employed to measuring the CFL and flow velocity of blood flow in this work.The PDMS micro flow channel used is 100 micrometers in width and 50 micrometers in deep.The RBC suspension is fed into the flow channel by the injection pump(NE-1000.USA),and the experiments are observed and recorded by the inverted microscope(IX70,Olympus,Japan)and high-speed camera(Memrecam GX-1,NAC,Japan)system.Three GA concentrations,i.e.,0.000 5,0.000 75,and 0.001 wt.%were used.Meanwhile,the effect of PFA at a concentration of 2wt.%work with GA was also investigated.Images of the flowing RBCs are processed mainly based on Memrecam GXLink.The results show that,the diameter of the RBC be treated is bigger and the shape of the RBC is became more flat after treated.Some of RBCs lost their biconcave structure.When the RBC suspension with 5%Hct flow in the microchannel,the CFL thickness decrease after being treated.And with concentrations of GA increase,the CFL thickness become thinner.The CFL thickness decrease significantly when GA and 2 wt.%PFA work combined.The velocity of RBCs decreases after treated with the GA or/and 2wt.%PFA.GA is known to relieve the dissolution of red blood cells during fluorescence labeling.On the other hand,the crosslinking of the aldehyde group(-cho)of GA with the amino group(-nh2)of RBC membrane protein will change the conformation of the membrane protein and its visco-elastic properties in turn.Then,the transparent fluidity orrheology characteristics of RBC is altered.Since GA and PFA are commonly used to immobilize red blood cells and keep the fluorescence constant,and PFA works similarly as GA,as a result,the variation of membrane protein conformation is intensified,and the membrane becomes stiffer.