Hemorheological disorders in diabetes mellitus

Revisiting the full blood count: Circulating blood cells and their role in coagulation

There has been an expansion in our understanding of the multifaceted roles of circulating blood cells in regulating haemostasis and contributing to thrombosis. Notably, there is greater recognition of the interplay between coagulation with inflammation and innate immune activation and the contribution of leucocytes. The full blood count (FBC) is a time-honoured test in medicine; however, its components are often viewed in isolation and without consideration of their haemostatic and thrombotic potential. Here, we review how the individual components of the FBC, that is, haemoglobin, platelets and leucocytes, engage with the haemostatic system and focus on both their quantitative and qualitative attributes. We also explore how this information can be harnessed into better management of people with multiple long-term conditions because of their higher risk of adverse clinical events.

Blood Viscosity Changes in Diabetes Mellitus: A 20-Year Bibliometric Review and Future Directions

Changes in hematological parameters due to diabetes are reflected in changes in whole blood viscosity (WBV). Understanding the impact of diabetes and its cardiovascular disease (CVD) complications can provide substantiation of how laboratory tests for WBV are useful to monitor the progression and treatment. The review examines research work done in the past 20 years to provide a framework for the present agenda. This was a narrative review that followed the standard Scale for the Assessment of Narrative Review Articles (SANRA) approach. It includes both conceptual and empirical reviews. WBV was appraised in the context of bibliographic research on diabetes and other related factors such as metabolic syndrome (MetS) and oxidative stress. The association of abnormal erythrocytes as well as the relationship between WBV and MetS is established. Changes in diabetes that contribute to the development of diabetic cardiovascular complications occur through the pathway of WBV physiology. However, longitudinal analysis is very limited. There is a dearth of longitudinal study data on WBV in diabetes management. This lack of data justifies a need for further studies, especially prospective and retrospective analysis, to investigate the prevalence of diabetes mellitus about the prevalence of cardiovascular complications indices, especially estimated WBV (eWBV) between periods and within cohorts.

Investigation of Zinc on hemorheological parameters in a rat model of diabetes

Diabetes mellitus (DM) is a complex, chronic metabolic disorder characterized by impaired regulation of blood glucose levels. Zinc (Zn) is an essential trace elements that plays a role in various physiological processes within the body, including those related to diabetes. The current study was investigated the effect of Zn supplementation on hemorheological parameters in a rat model of DM. After induction of DM, 32 male Wistar albino rats were divided into four groups: control, Zn, DM, and Zn+DM. Whole blood viscosity (WBV) was determined by using digital cone and plate viscometer and plasma viscosity (PV) was determined by a Coulter Harkness capillary viscometer. The rats in the DM Group showed a decrease in both Zn levels and body weight, as well as an increase in glucose levels when compared to the control group. Diabetic rats supplemented with Zn displayed lower blood glucose levels and higher concentrations of Zn compared to the DM Group. The higher PV and lower hematocrit level were measured in DM Group than control group and lower PV, higher hematocrit level were measured in Zn+DM group than DM Group. The WBV was measured at four different shear rates (57.6-115.2 - 172.8-230.4 s -1). A statistically significant increase was observed in the DM group compared to the control group. Additionally, a statistically significant decrease was observed in the Zn+DM Group compared to the DM Group at a shear rate of 230.4 s-1. Erythrocyte rigidity index (Tk) and oxygen delivery index (ODI) were computed under conditions of high shear rate. The rats in the DM group exhibited a reduction in ODI and an elevation in Tk in comparison to the control group. Conversely, the diabetic rats supplemented with Zn exhibited decreased Tk and increased ODI compared to the DM Group. Zn supplementation seems to have a potential beneficial effect for protecting adverse affect of diabetes on hemorheogical parameters and for maintaining vascular health.

Impact of different severity hyperglycemia on erythrocyte rheological properties1

BACKGROUND

The triad "insulin resistance, prediabetes, diabetes" is three independent neologies with characteristic features and development. In addition, each are characterized by progression and the possibility of transition from one form to other. Due to the fact that diabetes is one of the common diseases associated with high rates of disability, it is necessary to improve diagnostic methods and educational regimens for successful prevention and treatment of the disease.

OBJECTIVE

We investigated Band 3 protein (B3p) level, osmotic resistance of erythrocytes, the total antioxidant activity (TAA) of blood serum, level of HbA1 in group patients with insulin resistance (IR), prediabetes, and Type 2 Diabetes Mellitus (T2DM) and comparative with health control group.

METHODS

We used original, accurate research methods that measure the essence of the studied quantities.

RESULTS

Disruptions of glucose and insulin homeostasis ay lead to the initiation of oxidative stress (in our study demonstrated by a decrease of TAA of blood serum) increased redox-sensitive PTP activity and aberrant band 3 phosphorylation, potentially leading to reduced erythrocyte deformability. At the same time glycation of Hb during T2DM may affect its cross-link with membrane proteins, in particular with B3p, and although appears to limit its cross-linking and decrease its clusterization ability, induces alterations in the cytoskeletal matrix, and thereby decrease erythrocytes' osmotic resistance making them more susceptible to hemolysis.

CONCLUSIONS

The osmotic resistance of the erythrocytes can be used as a sensitive marker for the detection of the early stages of hyperglycemia (prediabetes). This set of clinical trials will make it possible to identify diseases that make up the triad at an early stage. Early detection of disorders and continued research in this direction will help in the development of a diagnostic scheme for the prevention of such patients. Based on our data, research into anti-oxidation drugs is very important. With the help of the array of studies described in the article and antioxidant treatment, the likelihood of successful treatment will increase.

Sialylated Glycan Bindings from SARS-CoV-2 Spike Protein to Blood and Endothelial Cells Govern the Severe Morbidities of COVID-19

Consistent with well-established biochemical properties of coronaviruses, sialylated glycan attachments between SARS-CoV-2 spike protein (SP) and host cells are key to the virus's pathology. SARS-CoV-2 SP attaches to and aggregates red blood cells (RBCs), as shown in many pre-clinical and clinical studies, causing pulmonary and extrapulmonary microthrombi and hypoxia in severe COVID-19 patients. SARS-CoV-2 SP attachments to the heavily sialylated surfaces of platelets (which, like RBCs, have no ACE2) and endothelial cells (having minimal ACE2) compound this vascular damage. Notably, experimentally induced RBC aggregation in vivo causes the same key morbidities as for severe COVID-19, including microvascular occlusion, blood clots, hypoxia and myocarditis. Key risk factors for COVID-19 morbidity, including older age, diabetes and obesity, are all characterized by markedly increased propensity to RBC clumping. For mammalian species, the degree of clinical susceptibility to COVID-19 correlates to RBC aggregability with p = 0.033. Notably, of the five human betacoronaviruses, the two common cold strains express an enzyme that releases glycan attachments, while the deadly SARS, SARS-CoV-2 and MERS do not, although viral loads for COVID-19 and the two common cold infections are similar. These biochemical insights also explain the previously puzzling clinical efficacy of certain generics against COVID-19 and may support the development of future therapeutic strategies for COVID-19 and long COVID patients.

A combined computational and experimental investigation of the filtration function of splenic macrophages in sickle cell disease

Being the largest lymphatic organ in the body, the spleen also constantly controls the quality of red blood cells (RBCs) in circulation through its two major filtration components, namely interendothelial slits (IES) and red pulp macrophages. In contrast to the extensive studies in understanding the filtration function of IES, fewer works investigate how the splenic macrophages retain the aged and diseased RBCs, i.e., RBCs in sickle cell disease (SCD). Herein, we perform a computational study informed by companion experiments to quantify the dynamics of RBCs captured and retained by the macrophages. We first calibrate the parameters in the computational model based on microfluidic experimental measurements for sickle RBCs under normoxia and hypoxia, as those parameters are not available in the literature. Next, we quantify the impact of key factors expected to dictate the RBC retention by the macrophages in the spleen, namely, blood flow conditions, RBC aggregation, hematocrit, RBC morphology, and oxygen levels. Our simulation results show that hypoxic conditions could enhance the adhesion between the sickle RBCs and macrophages. This, in turn, increases the retention of RBCs by as much as four-fold, which could be a possible cause of RBC congestion in the spleen of patients with SCD. Our study on the impact of RBC aggregation illustrates a 'clustering effect', where multiple RBCs in one aggregate can make contact and adhere to the macrophages, leading to a higher retention rate than that resulting from RBC-macrophage pair interactions. Our simulations of sickle RBCs flowing past macrophages for a range of blood flow velocities indicate that the increased blood velocity could quickly attenuate the function of the red pulp macrophages on detaining aged or diseased RBCs, thereby providing a possible rationale for the slow blood flow in the open circulation of the spleen. Furthermore, we quantify the impact of RBC morphology on their tendency to be retained by the macrophages. We find that the sickle and granular-shaped RBCs are more likely to be filtered by macrophages in the spleen. This finding is consistent with the observation of low percentages of these two forms of sickle RBCs in the blood smear of SCD patients. Taken together, our experimental and simulation results aid in our quantitative understanding of the function of splenic macrophages in retaining the diseased RBCs and provide an opportunity to combine such knowledge with the current knowledge of the interaction between IES and traversing RBCs to apprehend the complete filtration function of the spleen in SCD.

Trends in prescribing and outcomes in obese versus non-obese patients receiving rivaroxaban therapy: an observational study using real-world data

PURPOSE

To investigate real-world prescribing trends and clinical outcomes based on body mass index (BMI) categorization in patients who received rivaroxaban therapy.

METHODS

This was a retrospective cohort study involving all patients who received rivaroxaban therapy across all Hamad Medical Corporation (HMC) hospitals from 2015 to 2020.

RESULTS

The number of patients initiated on rivaroxaban therapy significantly increased from 152 (3.3%) in 2015 to 1342 (28.9%) in 2020 (p <0.001). Within BMI categories, a similar increasing trend was observed in underweight, normal, and overweight patients, while from 2018 to 2020, there was a decreasing trend in rivaroxaban prescribing in all obese classes. The prevalence rate of all-cause mortality differed significantly between the BMI groups, with the highest mortality being among morbidly obese patients (BMI ≥ 40 kg/m2) (p< 0.001). On the other hand, no significant differences were found between the BMI groups in terms of bleeding, pulmonary embolism, deep vein thrombosis and stroke incidences. Multivariate logistic regression analyses showed that the likelihood of all-cause mortality was significantly higher in overweight and all categories of obese patients compared to underweight patients: overweight (OR: 5.3, 95% CI: 2.3-11.9, p< 0.001); obese class 1 (OR: 5.4, 95% CI: 2.3 - 12.2, p< 0.001); obese class 2 (OR: 6.5, 95% CI: 2.7 - 15.6, p< 0.001); and obese class 3 (OR: 3.7, 95% CI: 1.6 - 8.7, p = 0.003).

CONCLUSIONS

Rivaroxaban prescribing has significantly increased over the years across general population, with a noticeable decline in obese population during the last few years (from 2018 onwards). Furthermore, an appreciable association was evident between all-cause mortality and BMI of these patients.

Comparative Analysis of Red Blood Cells, White Blood Cells, Platelet Count, and Indices in Type 2 Diabetes Mellitus Patients and Normal Controls: Association and Clinical Implications

Background

Diabetes mellitus (DM) is a major health burden affecting 537 million adults worldwide, characterized by chronic metabolic disorder and various complications. This case control study aimed to assess the impact of type 2 diabetes mellitus (T2DM), including hyperglycemia levels, on hematological parameters and complete blood count (CBC) derived parameters.

Methods

A total of 250 known diabetic patients from the Jazan Diabetic Center, Saudi Arabia, between January 2021 and December 2022, along with 175 healthy adult controls were recruited from Jazan Hospital's blood donation center. Demographic characteristics, medical histories, and relevant factors such as gender, age, BMI, treatment, disease duration, and comorbidities were collected with informed consent.

Results

The results of the red blood cell (RBC) count, RBC indices, and mean platelet volume showed significant differences between patients and controls, while the white cell (WBC) and platelet count were comparable between the two groups. CBC-derived parameters, especially neutrophil/lymphocyte ratio (NLR), and platelet/neutrophil ratio (PNR) exhibited significant differences.

Conclusion

CBC and derived parameters serve as inexpensive tools for T2DM patients monitoring, indicating early blood cell alterations and potential development of anemia. Further studies are needed to explore their role in predicting T2DM pathogenesis and progression, aiming to reduce severe complications, mortality and morbidity.

Biomechanical Investigation of Red Cell Sedimentation Using Blood Shear Stress and Blood Flow Image in a Capillary Chip

Blood image intensity has been used to detect erythrocyte sedimentation rate (ESR). However, it does not give information on the biophysical properties of blood samples under continuous ESR. In this study, to quantify mechanical variations of blood under continuous ESR, blood shear stress and blood image intensity were obtained by analyzing blood flows in the capillary channel. A blood sample is loaded into a driving syringe to demonstrate the proposed method. The blood flow rate is set in a periodic on-off pattern. A blood sample is then supplied into a capillary chip, and microscopic blood images are captured at specific intervals. Blood shear stress is quantified from the interface of the bloodstream in the coflowing channel. τ0 is defined as the maximum shear stress obtained at the first period. Simultaneously, ESRτ is then obtained by analyzing temporal variations of blood shear stress for every on period. AII is evaluated by analyzing the temporal variation of blood image intensity for every off period. According to the experimental results, a shorter period of T = 4 min and no air cavity contributes to the high sensitivity of the two indices (ESRτ and AII). The τ0 exhibits substantial differences with respect to hematocrits (i.e., 30-50%) as well as diluents. The ESRτ and AII showed a reciprocal relationship with each other. Three suggested properties represented substantial differences for suspended blood samples (i.e., hardened red blood cells, different concentrations of dextran solution, and fibrinogen). In conclusion, the present method can detect variations in blood samples under continuous ESR effectively.

Pathophysiology of Red Blood Cell Dysfunction in Diabetes and Its Complications

Diabetes Mellitus (DM) is a complex metabolic disorder associated with multiple microvascular complications leading to nephropathy, retinopathy, and neuropathy. Mounting evidence suggests that red blood cell (RBC) alterations are both a cause and consequence of disturbances related to DM-associated complications. Importantly, a significant proportion of DM patients develop varying degrees of anemia of confounding etiology, leading to increased morbidity. In chronic hyperglycemia, RBCs display morphological, enzymatic, and biophysical changes, which in turn prime them for swift phagocytic clearance from circulation. A multitude of endogenous factors, such as oxidative and dicarbonyl stress, uremic toxins, extracellular hypertonicity, sorbitol accumulation, and deranged nitric oxide metabolism, have been implicated in pathological RBC changes in DM. This review collates clinical laboratory findings of changes in hematology indices in DM patients and discusses recent reports on the putative mechanisms underpinning shortened RBC survival and disturbed cell membrane architecture within the diabetic milieu. Specifically, RBC cell death signaling, RBC metabolism, procoagulant RBC phenotype, RBC-triggered endothelial cell dysfunction, and changes in RBC deformability and aggregation in the context of DM are discussed. Understanding the mechanisms of RBC alterations in DM provides valuable insights into the clinical significance of the crosstalk between RBCs and microangiopathy in DM.

Association of the Red Cell Distribution Width With the Glycemic Index and Lipid Profile in Patients With Type 2 Diabetes Mellitus

Background The aim of this study was to assess the association between the red cell distribution width (RDW) and the hemoglobin A1C (HbA1c) and lipid profiles in patients with type 2 diabetes (T2DM). Materials and methods This case-control study included 130 individuals with T2DM disease who were admitted to the Diabetic Center in Taif, Saudi Arabia, between August and December 2022. The patients were divided into two groups: pre-diabetic (45 patients) and diabetic (85 patients). A total of 65 healthy people were included in the study as controls. The (HbA1c) level, lipid profile, and complete blood count (CBC) were determined for each participant, and differences in those parameters between the groups were evaluated using the one-way ANOVA test or Kruskal-Wallis test. The association between different parameters, including the RDW, was evaluated using the Pearson correlation coefficient. Results Both the pre-diabetic and diabetic patients were obese and had high concentrations of triglycerides, cholesterol, and low-density lipoprotein (LDL). None of the diabetic patients had anemia of any type. However, the RDW was higher in the diabetic group than in the healthy controls and a significant difference was detected. A positive correlation was detected between the RDW and the HbA1c levels and lipid profiles. Discussion The size of the red blood cells varied in patients with T2DM, as demonstrated by the high RDW values. The RDW showed a positive correlation with the glycemic index and with the lipid profile in patients with T2DM, suggesting that it is a useful prognostic marker for managing patients with T2DM.

Global Prevalence of Anemia Among Type 2 Diabetic Adult Patients: A Systematic Review and Meta-Analysis

Background

Anemia is a common and often overlooked hematological change observed in patients with diabetes mellitus. However, there is no global survey or health registry that estimates the pooled prevalence of anemia in patients with type 2 diabetes. Therefore, this study aimed to determine the global pooled prevalence of anemia among adult patients with type 2 diabetes.

Methods

This study was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. The study protocol was registered on PROSPERO with the reference number (CRD42022327135), and the link provided (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022327135) display the published methodology. Previously published articles were searched in PubMed/Medline, Cochrane Library, WHO Global Index Medicus, African Journals Online, ScienceDirect, Google Scholar, and Google from October 26 to November 09, 2022. The quality of the included studies was assessed using the Joanna Briggs Institute Critical Appraisal tool. Random-effects model was used to estimate the pooled prevalence of anemia. The degree of heterogeneity among the included studies was assessed using I2 statistics. Publication bias was detected using funnel plot symmetry analysis supplemented by Egger's and Begg's tests.

Results

Twenty-four studies with a total number of 19,118 participants were included in this systematic review and meta-analysis. The overall pooled prevalence of anemia among type 2 diabetic adult patients was 27.0% (95% CI: 24.0, 31.0, I2 = 96.45%; P< 0.001). Geographical and time-based subgroup analysis showed that higher prevalence of anemia was observed in Africa region 28.0% (95% CI: 17.0, 39.0) and from 2015 to 2022, 28.0% (95% CI: 24.0, 33.0), respectively.

Conclusion

Anemia is a moderate public health problem among adult patients with type 2 diabetes. Nearly one in four patients with type 2 diabetes develops anemia. Therefore, considering the negative impact of anemia, it is important to include anemia screening in the routine assessment of diabetes-related complications.

Interdependence of Rheological and Biochemical Parameters of Blood in a Group of Patients with Clinically Silent Multifocal Vascular Cerebral Lesions

BACKGROUND

Hemorheology is a field of science which often becomes interesting to researchers studying impairments related to blood flow disturbances. Clinically silent vascular cerebral lesions (CSVCLs) are considered a problem of great importance in neurology.

OBJECTIVE

This work aimed to analyze the interdependencies of the rheological and biochemical parameters of the blood.

METHODS

The group of patients included persons with clinically silent multifocal vascular cerebral lesions diagnosed using neuroimaging. The control group had no symptoms in the central nervous system (CNS). We analyzed hemorheological profiles in 69 patients with CSVCLs diagnosed via magnetic resonance imaging (MR) or 64-row computer tomography measurements. Rheological data were acquired using a rotary-oscillating rheometer, the Contraves LS-40, an instrument dedicated to blood viscosity measurements. For each sample, the hematocrit value was measured using the standard method. Analysis of erythrocytes' aggregability and deformability was performed using the rheological model of Quemada. Biochemical tests of blood were also performed.

RESULTS

The results of rheological and biochemical studies were compared with those obtained in the control group. Special attention was paid to the correlation analysis of rheological and biochemical parameters.

CONCLUSIONS

Such correlations were found, e.g., between the red cells' deformability and the fibrinogen level. The results improve our understanding of blood flow hemodynamics by analyzing the shear-dependent behavior of the aggregation and deformability of red blood cells.

A combined computational and experimental investigation of the filtration function of splenic macrophages in sickle cell disease

Being the largest lymphatic organ in the body, the spleen also constantly controls the quality of red blood cells (RBCs) in circulation through its two major filtration components, namely interendothelial slits (IES) and red pulp macrophages. In contrast to the extensive studies in understanding the filtration function of IES, there are relatively fewer works on investigating how the splenic macrophages retain the aged and diseased RBCs, i.e., RBCs in sickle cell disease (SCD). Herein, we perform a computational study informed by companion experiments to quantify the dynamics of RBCs captured and retained by the macrophages. We first calibrate the parameters in the computational model based on microfluidic experimental measurements for sickle RBCs under normoxia and hypoxia, as those parameters are not available in the literature. Next, we quantify the impact of a set of key factors that are expected to dictate the RBC retention by the macrophages in the spleen, namely, blood flow conditions, RBC aggregation, hematocrit, RBC morphology, and oxygen levels. Our simulation results show that hypoxic conditions could enhance the adhesion between the sickle RBCs and macrophages. This, in turn, increases the retention of RBCs by as much as five-fold, which could be a possible cause of RBC congestion in the spleen of patients with SCD. Our study on the impact of RBC aggregation illustrates a 'clustering effect', where multiple RBCs in one aggregate can make contact and adhere to the macrophages, leading to a higher retention rate than that resulting from RBC-macrophage pair interactions. Our simulations of sickle RBCs flowing past macrophages for a range of blood flow velocities indicate that the increased blood velocity could quickly attenuate the function of the red pulp macrophages on detaining aged or diseased RBCs, thereby providing a possible rationale for the slow blood flow in the open circulation of the spleen. Furthermore, we quantify the impact of RBC morphology on their tendency to be retained by the macrophages. We find that the sickle and granular-shaped RBCs are more likely to be filtered by macrophages in the spleen. This finding is consistent with the observation of low percentages of these two forms of sickle RBCs in the blood smear of SCD patients. Taken together, our experimental and simulation results aid in our quantitative understanding of the function of splenic macrophages in retaining the diseased RBCs and provide an opportunity to combine such knowledge with the current knowledge of the interaction between IES and traversing RBCs to apprehend the complete filtration function of the spleen in SCD.

Safety of COVID-19 Vaccines among Patients with Type 2 Diabetes Mellitus: Real-World Data Analysis

BACKGROUND

Little is known about the adverse events (AEs) associated with coronavirus disease 2019 (COVID-19) vaccination in patients with type 2 diabetes mellitus (T2DM).

METHODS

This study used vaccine AE reporting system data to investigate severe AEs among vaccinated patients with T2DM. A natural language processing algorithm was applied to identify people with and without diabetes. After 1:3 matching, we collected data for 6,829 patients with T2DM and 20,487 healthy controls. Multiple logistic regression analysis was used to calculate the odds ratio for severe AEs.

RESULTS

After COVID-19 vaccination, patients with T2DM were more likely to experience eight severe AEs than controls: cerebral venous sinus thrombosis, encephalitis myelitis encephalomyelitis, Bell's palsy, lymphadenopathy, ischemic stroke, deep vein thrombosis (DVT), thrombocytopenia (TP), and pulmonary embolism (PE). Moreover, patients with T2DM vaccinated with BNT162b2 and mRNA-1273 were more vulnerable to DVT and TP than those vaccinated with JNJ-78436735. Among patients with T2DM administered mRNA vaccines, mRNA-1273 was safer than BNT162b2 in terms of the risk of DVT and PE.

CONCLUSION

Careful monitoring of severe AEs in patients with T2DM may be necessary, especially for those related to thrombotic events and neurological dysfunctions after COVID-19 vaccination.

In silico modeling of patient-specific blood rheology in type 2 diabetes mellitus

Increased blood viscosity in type 2 diabetes mellitus (T2DM) is a risk factor for the development of insulin resistance and diabetes-related vascular complications; however, individuals with T2DM exhibit heterogeneous hemorheological properties, including cell deformation and aggregation. Using a multiscale red blood cell (RBC) model with key parameters derived from patient-specific data, we present a computational study of the rheological properties of blood from individual patients with T2DM. Specifically, one key model parameter, which determines the shear stiffness of the RBC membrane (μ) is informed by the high-shear-rate blood viscosity of patients with T2DM. At the same time, the other, which contributes to the strength of the RBC aggregation interaction (D0), is derived from the low-shear-rate blood viscosity of patients with T2DM. The T2DM RBC suspensions are simulated at different shear rates, and the predicted blood viscosity is compared with clinical laboratory-measured data. The results show that the blood viscosity obtained from clinical laboratories and computational simulations are in agreement at both low and high shear rates. These quantitative simulation results demonstrate that the patient-specific model has truly learned the rheological behavior of T2DM blood by unifying the mechanical and aggregation factors of the RBCs, which provides an effective way to extract quantitative predictions of the rheological properties of the blood of individual patients with T2DM.

Hyperbaric oxygenation improve red blood cell deformability in patients with acute or chronic inflammation

INTRODUCTION

Red blood cells (RBC) are one of the key elements of the microcirculation. Their ability to pass through capillaries and to deliver oxygen to cells is due to their large degree of deformability linked to the characteristics of the RBC membrane. Alterations in RBC deformability as a result of membrane damage, linked in part to increased synthesis of reactive oxygen species (ROS), can be observed in several diseases, such as sepsis, and may contribute to the altered microcirculation observed in these pathologies. Hyperbaric oxygen therapy (HBOT), with inhalation of 100 % oxygen, has been proposed in several acute or chronic pathologies, including carbon monoxide poisoning.

OBJECTIVE

We investigated the effects of HBOT on oxidative stress from ROS produced by myeloperoxidase (MPO) and on RBC deformability in patients with acute or chronic inflammation (n = 10), in patients with acute carbon monoxide poisoning (n = 10), and in healthy volunteers (n = 10).

METHODS

RBC deformability was evaluated before and after HBOT in the various populations using the ektacytometry technique (Laser-assisted Optical Rotational Red Cell Analyzer - LORRCA). Deformability was determined by the elongation index (EI) in relation to the shear stress (SS) over a range of 0.3 to 50 Pa. Oxidative stress was estimated through changes in proteins (chlorotyrosine and homocitrulline) induced by MPO activity measured by liquid chromatography-tandem mass spectrometry analysis.

RESULTS

Before HBOT, EI was significantly lower in patients with acute or chronic inflammation than in healthy volunteers and patients with acute carbon monoxide poisoning for the majority of SS values studied. After one session of HBOT, the EI was significantly higher than before HBOT for SS values of 1.93 Pa or higher in patients with acute or chronic inflammation. This effect remains constant after 10 sessions. There were no differences before and after HBOT in protein or amino acid oxidation due to ROS generation mediated by MPO in the three populations.

CONCLUSIONS

Our results confirm altered RBC deformability in patients with acute and chronic conditions associated with an underlying inflammatory process. HBOT improves deformability only after one session and therefore may improve microcirculation in this population. According to our results, this improvement does not seem mediated by the ROS pathway via MPO. These results need to be confirmed in a larger population.

Effects of sarpogrelate on blood viscosity

The objective of the present study was to evaluate the effects and safety of sarpogrelate hydrochloride (sarpogrelate) in patients with elevated blood viscosity (BV), after 12 and 24 weeks of twice (BID) or thrice (TID) daily administrations of sarpogrelate (100 mg). The participants received oral sarpogrelate administration for 24 weeks and visited the hospital every 12 ± 2 week for blood viscosity measurements at shear rates of 5 and 300 s^-1. The BV measured at shear rate of 5 s^-1 in male patients decreased significantly from 18.91 cP at the baseline to 16.3 cP after 24 weeks of sarpogrelate administration (13.6 % drop, p < 0.001). The BV measured at 5 s^-1 in female decreased more significantly from 17.5 cP at the baseline to 13.4 cP after 24 weeks of sarpogrelate administration (23.0 % drop, p < 0.001). In summary, sarpogrelate may be considered as a possible therapeutic option for improving BV in patients with elevated blood viscosity. In particular, the reduction of the low-shear BV with the help of a viscosity-reducing drug such as sarpogrelate may be considered as a potentially new pharmacological tool for microvascular disease.

An examination of causal associations and shared risk factors for diabetes and cardiovascular diseases in the East Asian population: A Mendelian randomization study

BACKGROUND

One of the major contributors to disability and mortality among diabetics is cardiovascular disease (CVD), with coronary artery disease (CAD) as the most prevalent type. However, previous studies have provided controversial evidence linking diabetes to other types of CVDs, such as atrial fibrillation (AF). In addition, the risk factors that predispose people to the risk of diabetes and its complications differ across ethnicities, but the disease risk profiles in the East Asian population have been less investigated.

METHODS

The causal association between type 2 diabetes (T2D) and two types of CVDs (i.e., AF and CAD) in the East Asian population was first studied using Mendelian randomization (MR) analyses. Next, we examined the causal effect of 49 traits on T2D and CAD to identify their separate and shared risk factors in East Asians. A causal mediation analysis was performed to examine the role of T2D in mediating the relationship between the identified shared risk factors and CAD.

RESULTS

T2D was causally associated with CAD, but not AF, in East Asians. A screening of the risk factors indicated that six and 11 traits were causally associated with T2D and CAD, respectively, with suggestive levels of evidence. Alkaline phosphatase (ALP) was the only trait associated with both T2D and CAD, as revealed by the univariable MR analyses. Moreover, the causal association between ALP and CAD no longer existed after adjusting T2D as a covariable in the causal mediation study.

CONCLUSION

Our study highlights the risk profiles in the East Asian population, which is important in formulating targeted therapies for T2D and CVDs in East Asians.

The Pathogenic Role of Oxidative Stress, Cytokine Expression, and Impaired Hematological Indices in Diabetic Cardiovascular Diseases

A simultaneous increase in the prevalence of diabetes mellitus (DM), a risk factor for cardiovascular diseases (CVDs), has contributed to the escalation of CVD related mortalities. To date, oxidative stress and inflammation are increasingly recognized as significant drivers of cardiovascular complications in patients with diabetes. Therefore, this study aims to explore the correlation between oxidative stress, inflammation, and hematological indices in diabetic patients with CVDs. Patients were allocated into five groups: healthy controls; nondiabetic patients with myocardial infarction; diabetic patients with myocardial infarction; nondiabetic patients with heart failure; and diabetic patients with heart failure. The results revealed that the malondialdehyde levels were increased; whereas superoxide dismutase enzyme activities were markedly reduced in all CVD groups compared with those of healthy controls. Although the mRNA expression levels of interleukin (IL)-6, IL-18, and IL-38 were significantly increased, those of the anti-inflammatory cytokine, IL-35, have been reduced in all CVD groups compared with healthy controls. Regarding hematological indices, hematocrit, red blood cell distribution width, mean platelet (PLT) volume, plateletcrit, PLT distribution width, leukocyte count, and PLT-to-lymphocyte and neutrophil-to-lymphocyte ratios were markedly increased in the diabetic and nondiabetic CVD groups compared with those of the healthy controls. Oxidative stress and cytokine biomarkers may play a significant role in the complications of diabetic cardiomyopathy. Moreover, hematological indices are particularly sensitive to systemic inflammatory changes and are novel markers for the early detection of diabetic cardiomyopathy.

Blood Rheology Alterations in Patients with Cardiovascular Diseases

Blood rheology is an important determinant of blood flow but is probably one of the most neglected areas in clinical literature and practice. Blood viscosity changes according to shear rates and depends on cellular and plasma factors. RBCs' aggregability and deformability are the main determinants of local flow characteristics in areas with lower and higher shear rates, but plasma viscosity is the main regulatory factor of flow resistance in the microcirculation. In individuals with altered blood rheology, the mechanical stress to vascular walls induces endothelial injury and vascular remodelling, and promotes atherosclerosis. Increased values of whole blood viscosity and plasma viscosity are correlated with cardiovascular risk factors and adverse cardiovascular events. The long-term effects of physical exercise can produce a hemorheological fitness that protects against cardiovascular diseases.

Red Blood Cell Parameters and Their Correlation with Glycemic Control Among Type 2 Diabetic Adult Patients in Eastern Ethiopia: A Comparative Cross-Sectional Study

Background

Diabetes has been proposed to inflict an insult on the hematopoietic milieu marked by changes in hematological indices including red blood cell parameters. Thus, this study aimed to assess the red blood cell parameters and their correlation with glycemic control in type 2 diabetic adult patients in comparison with apparently healthy individuals.

Methods

A comparative cross-sectional study was conducted at the chronic illness clinic of Hiwot Fana Comprehensive Specialized University Hospital from May 20 to July 10, 2022. A total of 220 (110 type 2 diabetic patients and 110 controls) study participants were selected by a simple random sampling technique. Five milliliters of venous blood were collected by the vacutainer blood collection technique. Red blood cell parameters and blood glucose levels were determined using UniCel DxH 800 and Biosystems A25 analyzers, respectively. Independent sample t-test and Pearson correlation test were used for the data analysis. P-value <0.05 was considered statistically significant.

Results

Statistically significant difference was observed in RBC parameters of T2DM patients and the control group. The mean RBC count, Hgb, Hct (P < 0.001), and MCHC (P = 0.002) in patients with type 2 diabetes was significantly lower than in the control group. However, the mean of RDW was significantly increased in type 2 diabetic patient groups than in the control group (P < 0.001). The mean RBC count, Hct, and Hgb in patients with good glycemic control were significantly higher than the patients with poor glycemic control. Besides, a statistically significant negative correlation was observed between glycemic control and RBC count, Hgb, and Hct level in diabetic patients.

Conclusion

In this study, a statistically significant difference was observed in red blood cell parameters of type 2 diabetic patients compared to the control group. A significant negative correlation was noted between glycemic control and RBC parameters in type 2 diabetic patients. Therefore, evaluation of RBC parameters should be considered for better management of patients with type 2 diabetes mellitus.

Monitoring and recovery of hyperglycaemia-induced endothelial dysfunction with rheopheresis in diabetic lower extremity ulceration with hyperviscosity

AIMS

Rheopheresis is an extracorporeal haematotherapy that improves haemorheological status by filtering proteins that enhance blood viscosity. It also has anti-inflammatory effects by removing inflammatory cytokines. Our study aims to examine the effects of rheopheresis on the endothelial status in diabetic lower extremity ulceration.

METHODS

In vitro experiments were performed in a HUVEC model to mimic hyperglycaemic stress. We determined the changes in gene expression levels of IL-6, IL-8, TNF-alpha, endothelin convertase enzyme, ET-1, and NO synthase, as well as the ROS and intracellular GSH levels upon hyperglycaemia. In in vivo studies, two rheopheresis procedures were performed on seven patients with diabetic lower extremity ulceration with hyperviscosity, and we measured the changes in plasma concentrations of ET-1, TXB2, SOD enzyme activity, and extracellular components of the glutathione pool depending on treatments.

RESULTS

Our results showed that hyperglycaemia increases endothelial expression of inflammatory cytokines, ET-1, and endothelin convertase enzyme, while NO synthase was decreased. As a result of rheopheresis, we observed decreased ET-1 and TXB2 concentrations in the plasma and beneficial changes in the parameters of the glutathione pool.

CONCLUSION

To summarize our results, hyperglycaemia-induced oxidative stress and endothelial inflammation can be moderated by rheopheresis in diabetic lower extremity ulceration with hyperviscosity.

Lingering Dynamics of Type 2 Diabetes Mellitus Red Blood Cells in Retinal Arteriolar Bifurcations

It has been proven that the deformability of red blood cells (RBC) is reduced owing to changes in mechanical properties, such as diabetes mellitus and hypertension. To probe the effects of RBC morphological and physical parameters on the flow field in bifurcated arterioles, three types of RBC models with various degrees of biconcave shapes were built based on the in vitro experimental data. The dynamic behaviors of the RBCs in shear flow were simulated to validate the feasibility of the finite element-Arbitrary Lagrangian-Eulerian method with a moving mesh. The influences of the shear rate and viscosity ratios on RBC motions were investigated. The motion of RBCs in arteriolar bifurcations was further simulated. Abnormal variations in the morphological and physical parameters of RBCs may lead to diminished tank-tread motion and enhanced tumbling motion in shear flow. Moreover, abnormal RBC variations can result in slower RBC motion at the bifurcation with a longer transmit time and greater flow resistance, which may further cause inadequate local oxygen supply. These findings would provide useful insights into the microvascular complications in diabetes mellitus.

Effect of Functional Electrical Stimulation on Capillary Blood Flow to Muscle

Functional electrical stimulation (FES) modifies red blood cells (RBCs) flux in blood capillaries of muscle. In this work, we aim to investigate changes in the RBC flux in small and large capillaries due to FES using zinc oxide nanowires (ZnO NWs) based electrode at different stimulation parameters. The RBC flux was significantly increased immediately after stimulation, which was evident from decreasing light intensity measured in the region of interest. Clinical Relevance- FES has numerous forms and functions. The benefit of FES is the increased blood flow to a muscle which is contracted abnormally. This work explores the use of FES to increase the blood flow and RBC flux in blood capillaries of stimulated muscle as FES generate muscle contraction and absorption.

Hemorheological and microvascular disturbances in patients with type 2 diabetes mellitus

BACKGROUND: In the blood vessels the impaired hemorheological parameters in patients with type 2 diabetes mellitus (T2DM) could lead to elevated flow resistance, increased forces at the endothelial wall and to microvascular disturbances. OBJECTIVE: The aim of the study is to investigate the hemorheological variables and the changes of the skin blood flow responses to cold stress in T2DM patients. METHODS: The basic hemorheological parameters: hematocrit (Ht), fibrinogen (Fib), whole blood viscosity (WBV) and plasma viscosity (PV) were examined in 20 patients with T2DM and a control group of 10 healthy age and sex matched controls. The mechanisms of vascular tone regulation were investigated using the wavelet analysis of the skin temperature oscillations (WAST). The degrees of the microvascular tone changes were determined during a cold test in the endothelial (0.02–0.0095 Hz), neurogenic (0.05– 0.02 Hz) and myogenic (0.05– 0.14 Hz) frequency ranges. RESULTS: Significant increase of Fib and WBV in the patients in comparison to controls was found. The mean values of the amplitudes of the skin temperature (ST) pulsations decreased significantly during the cold stress only in the endothelial frequency range for the diabetic patients. CONCLUSIONS: The results of our study reveal parallel impairment of the blood rheological parameters and the cutaneous microcirculation in T2DM patients.

Quantification and Improvement of the Dynamics of Human Serum Albumin and Glycated Human Serum Albumin with Astaxanthin/Astaxanthin-Metal Ion Complexes: Physico-Chemical and Computational Approaches

Glycated human serum albumin (gHSA) undergoes conformational changes and unfolding events caused by free radicals. The glycation process results in a reduced ability of albumin to act as an endogenous scavenger and transporter protein in diabetes mellitus type 2 (T2DM) patients. Astaxanthin (ASX) in native form and complexed with metal ions (Cu²⁺ and Zn²⁺) has been shown to prevent gHSA from experiencing unfolding events. Furthermore, it improves protein stability of gHSA and human serum albumin (HSA) as it is shown through molecular dynamics studies. In this study, the ASX/ASX-metal ion complexes were reacted with both HSA/gHSA and analyzed with electronic paramagnetic resonance (EPR) spectroscopy, rheology and zeta sizer (particle size and zeta potential) analysis, circular dichroism (CD) spectroscopy and UV-Vis spectrophotometer measurements, as well as molecular electrostatic potential (MEP) and molecular docking calculations. The addition of metal ions to ASX improves its ability to act as an antioxidant and both ASX or ASX-metal ion complexes maintain HSA and gHSA stability while performing their functions.

Critical shear stress of red blood cells as a novel integrated biomarker for screening chronic kidney diseases in cases of type 2 diabetes

BACKGROUND:

The glomerular filtration rate (GFR) and albumin-to-creatinine ratio (ACR) have been widely used to identify and manage diabetic kidney disease (DKD). However, classifications based on these two indices do not always concur in terms of DKD diagnosis; for example, cases of high ACR with normal GFR or normal ACR with low GFR may occur. A recent study suggested that critical shear stress (CSS), a hemorheological parameter to represent aggregating force of red blood cells (RBCs), is a potential screening index for DKD. In the present study, we investigated the diagnostic potential of CSS for DKD according to the KDIGO 2012 Guideline.

METHODS:

A total of 378 patients with type 2 diabetes who visited Yeungnam University Hospital between 2014 and 2017 were included. CSS was measured using a transient microfluidic hemorheometer, Rheoscan-D300® (Rheomeditech, Seoul, Republic of Korea) with whole blood. Patients who were DKD negative (green zone) were compared with patients who were DKD positive (red zone) as Model 1 and patients at risk for (orange zone) and red zones as Model 2, respectively.

RESULTS:

After exclusion criteria such as eGFR < 30 mL/min/1.73 m², alcoholism, and macrovascular complications were applied, the sensitivity and specificity were 100% and 77.8% for Model 1 and 75.0% and 72.0% for Model 2, respectively. The diagnostic accuracy measures of the CSS for Model 1 were found to be highly accurate or have the potential to alter clinical decisions. Similarly, the diagnostic accuracy measures of CSS for Model 2 were found to provide useful information, despite them expanding to the orange and red zones.

CONCLUSION:

DKD was successfully identified using a novel integrated hemorheological index of CSS that satisfied both ACR and GFR criteria. Therefore, CSS may be useful for the additive diagnosis of DKD with GFR and uACR.

Blood Viscosity in Subjects With Type 2 Diabetes Mellitus: Roles of Hyperglycemia and Elevated Plasma Fibrinogen

The viscosity of blood is an indicator in the understanding and treatment of disease. An elevated blood viscosity has been demonstrated in patients with Type 2 Diabetes Mellitus (T2DM), which might represent a risk factor for cardiovascular complications. However, the roles of glycated hemoglobin (HbA1c) and plasma fibrinogen levels on the elevated blood viscosity in subjects with T2DM at different chronic glycemic conditions are still not clear. Here, we evaluate the relationship between the blood viscosity and HbA1c as well as plasma fibrinogen levels in patients with T2DM. The experimental data show that the mean values of the T2DM blood viscosity are higher in groups with higher HbA1c levels, but the correlation between the T2DM blood viscosity and the HbA1c level is not obvious. Instead, when we investigate the influence of plasma fibrinogen level on the blood viscosity in T2DM subjects, we find that the T2DM blood viscosity is significantly and positively correlated with the plasma fibrinogen level. Further, to probe the combined effects of multiple factors (including the HbA1c and plasma fibrinogen levels) on the altered blood viscosity in T2DM, we regroup the experimental data based on the T2DM blood viscosity values at both the low and high shear rates, and our results suggest that the influence of the elevated HbA1c level on blood viscosity is quite limited, although it is an important indicator of glycemic control in T2DM patients. Instead, the elevated blood hematocrit, the enhanced red blood cell (RBC) aggregation induced by the increased plasma fibrinogen level, and the reduced RBC deformation play key roles in the determination of blood viscosity in T2DM. Together, these experimental results are helpful in identifying the key determinants for the altered T2DM blood viscosity, which can be used in future studies of the hemorheological disturbances of T2DM patients.

Normalization of Blood Viscosity According to the Hematocrit and the Shear Rate

The rheological properties of blood depend highly on the properties of its red blood cells: concentration, membrane elasticity, and aggregation. These properties affect the viscosity of blood as well as its shear thinning behavior. Using an experimental analysis of the interface advancement of blood in a microchannel, we determine the viscosity of different samples of blood. In this work, we present two methods that successfully normalize the viscosity of blood for a single and for different donors, first according to the concentration of erythrocytes and second according to the shear rate. The proposed methodology is able to predict the health conditions of the blood samples by introducing a non-dimensional coefficient that accounts for the response to shear rate of the different donors blood samples. By means of these normalization methods, we were able to determine the differences between the red blood cells of the samples and define a range where healthy blood samples can be described by a single behavior.

Microfluidics Approach to the Mechanical Properties of Red Blood Cell Membrane and Their Effect on Blood Rheology

In this article, we describe the general features of red blood cell membranes and their effect on blood flow and blood rheology. We first present a basic description of membranes and move forward to red blood cell membranes' characteristics and modeling. We later review the specific properties of red blood cells, presenting recent numerical and experimental microfluidics studies that elucidate the effect of the elastic properties of the red blood cell membrane on blood flow and hemorheology. Finally, we describe specific hemorheological pathologies directly related to the mechanical properties of red blood cells and their effect on microcirculation, reviewing microfluidic applications for the diagnosis and treatment of these diseases.

Recent Advances in Computational Modeling of Biomechanics and Biorheology of Red Blood Cells in Diabetes

Diabetes mellitus, a metabolic disease characterized by chronically elevated blood glucose levels, affects about 29 million Americans and more than 422 million adults all over the world. Particularly, type 2 diabetes mellitus (T2DM) accounts for 90-95% of the cases of vascular disease and its prevalence is increasing due to the rising obesity rates in modern societies. Although multiple factors associated with diabetes, such as reduced red blood cell (RBC) deformability, enhanced RBC aggregation and adhesion to the endothelium, as well as elevated blood viscosity are thought to contribute to the hemodynamic impairment and vascular occlusion, clinical or experimental studies cannot directly quantify the contributions of these factors to the abnormal hematology in T2DM. Recently, computational modeling has been employed to dissect the impacts of the aberrant biomechanics of diabetic RBCs and their adverse effects on microcirculation. In this review, we summarize the recent advances in the developments and applications of computational models in investigating the abnormal properties of diabetic blood from the cellular level to the vascular level. We expect that this review will motivate and steer the development of new models in this area and shift the attention of the community from conventional laboratory studies to combined experimental and computational investigations, aiming to provide new inspirations for the development of advanced tools to improve our understanding of the pathogenesis and pathology of T2DM.

Computational investigation of blood cell transport in retinal microaneurysms

Microaneurysms (MAs) are one of the earliest clinically visible signs of diabetic retinopathy (DR). MA leakage or rupture may precipitate local pathology in the surrounding neural retina that impacts visual function. Thrombosis in MAs may affect their turnover time, an indicator associated with visual and anatomic outcomes in the diabetic eyes. In this work, we perform computational modeling of blood flow in microchannels containing various MAs to investigate the pathologies of MAs in DR. The particle-based model employed in this study can explicitly represent red blood cells (RBCs) and platelets as well as their interaction in the blood flow, a process that is very difficult to observe in vivo. Our simulations illustrate that while the main blood flow from the parent vessels can perfuse the entire lumen of MAs with small body-to-neck ratio (BNR), it can only perfuse part of the lumen in MAs with large BNR, particularly at a low hematocrit level, leading to possible hypoxic conditions inside MAs. We also quantify the impacts of the size of MAs, blood flow velocity, hematocrit and RBC stiffness and adhesion on the likelihood of platelets entering MAs as well as their residence time inside, two factors that are thought to be associated with thrombus formation in MAs. Our results show that enlarged MA size, increased blood velocity and hematocrit in the parent vessel of MAs as well as the RBC-RBC adhesion promote the migration of platelets into MAs and also prolong their residence time, thereby increasing the propensity of thrombosis within MAs. Overall, our work suggests that computational simulations using particle-based models can help to understand the microvascular pathology pertaining to MAs in DR and provide insights to stimulate and steer new experimental and computational studies in this area.

Evaluation of Red Blood Cell Parameters as a Biomarker for Long-Term Glycemic Control Monitoring Among Type 2 Diabetic Patients in Southwest Ethiopia: A Cross-Sectional Study

OBJECTIVE

The main aim of this study was to assess red blood cell parameters as a biomarker for long-term glycemic monitoring among T2 DM patients.

METHODS

Facility-based cross-sectional study through a consecutive sampling technique was conducted among 124 T2 DM patients at the chronic illness follow-up clinic of Jimma Medical Center (JMC) from July 27 to August 31, 2020. A structured questionnaire was used to collect socio-demographic and clinical-related data. Five milliliters of the blood specimen were collected from each eligible T2 DM patient. Glycated hemoglobin (HbA1c) and red blood cell parameters were determined by Cobas 6000 and DxH 800 fully automated analyzers, respectively. Data were entered into EpiData software version 3.1 and exported to SPSS 25 version for analysis. Independent t-test and Pearson's correlation coefficient were used to address the research questions. A P-value <0.05 was considered statistically significant.

RESULTS

The mean age of study participants was 51.84± 11.6 years. Moreover, 60.5% of T2 DM patients were in poor glycemic control. There was a significant mean difference between good and poor glycemic controlled T2 DM patients in red blood cell count (4.79±0.5 vs 4.38±0.8), hemoglobin (14.13±1.4 vs 13.60±1.6), mean corpuscular volume (89.52±4.7 vs 92.62±7.5), mean corpuscular hemoglobin (29.63±1.6 vs 30.77±2.9), and red cell distribution width (13.68±1.1 vs 14.63±1.2) respectively. Red blood cell count was inversely correlated (r=-0.280, p=0.002) with HbA1c while mean corpuscular volume (r=0.267, p=0.003), mean corpuscular hemoglobin (r=0.231, p=0.010), and red cell distribution width (r= 0.496, p=0.000) were positively correlated with level of HbA1c.

CONCLUSION

Red cell count, mean corpuscular volume, mean corpuscular hemoglobin, and red cell distribution width could be useful indicators to monitor the glycemic status of T2 DM patients instead of HbA1c, though large prospective studies should be considered.

Hemorheological Parameters in Diabetic Patients: Role of Glucose Lowering Therapies

Diabetes mellitus influences several important hemorheological parameters including blood viscosity, erythrocyte aggregation and deformability. In the present study, 159 type-2 diabetic patients and 25 healthy controls were involved. Patient's age, body weight, body mass index (BMI), smoking habits, physical activity, history of cardiovascular diseases, current antidiabetic therapy and concomitant medication were recorded. Patients were grouped according to their antidiabetic treatment with insulin, or with one or more of the following antidiabetic drugs: metformin, sulfonylureas, acarbose, or no antidiabetic therapy. Hemorheological measurements (hematocrit, erythrocyte aggregation, plasma fibrinogen, whole blood and plasma viscosity), von Willebrand factor activity, and platelet aggregation measurements were performed. Platelet aggregation was investigated with the method of Born. Plasma viscosity and red blood cell aggregation were significatly higher in diabetes. No significant difference was found in hemorheological parameters between different antidiabetic regimens. Whole blood and plasma viscosity and red blood cell aggregation correlated with glucose levels but not with HbA1C levels. In conclusion, plasma and whole blood viscosity, as well as red blood cell aggregation appear to be associated with concurrent hyperglycemia, but not with the quality of glycemic control or the applied antidiabetic treatment. Platelet aggregation induced by ADP or epinephrine does not seem to be associated with diabetes even at subthreshold doses.

The effect of rheopheresis treatment on the cytokine profile in diabetic foot syndrome with hyperviscosity in the aspect of clinical changes: A preliminary study

BACKGROUND

Rheopheresis is a selective extracorporal double cascade filtration treatment, which can extract high molecular weight proteins being responsible for hyperviscosity. As the whole blood and plasma viscosity decrease microcirculation improves.

OBJECTIVE

In this preliminary study we aimed to analyze additional beneficial effects of rheopheresis treatment with changes of pro-inflammantory cytokine levels in diabetic foot syndrome patients.

METHODS

Two rheopheresis treatments were performed for 6 patients with diabetic foot ulcer and/or neuropathy on consecutive days. Before and after the treatments whole blood and plasma viscosity, as well as IL-6, IL-8, and TNF-alpha serum levels were determined, and complex angiological and ENG examinations were performed.

RESULTS

Rheopheresis decreased the whole blood and plasma viscosity, and the serum levels of IL-6, IL-8, and TNF-alpha were markedly reduced. The life quality of the patients improved, the ulcers healed, the pain decreased. Daily dose of analgesics decreased in the follow-up period (6 months). The ENG showed improving amplitude and/or normalizing conduction speed.

CONCLUSION

Application of rheopheresis in patients with diabetic foot syndrome has a beneficial effect, providing favorable rheological condition, normalizing cytokine profile and reducing the sensorineural symptoms.

Effect of Direct Oral Anticoagulants for Ulcer Epithelization and Laser Doppler Flowmetry Parameters In Patients with Diabetic Foot Syndrome and Atrial Fibrillation

Aim. To study changes in epithelialization of diabetic foot ulcers and parameters of laser Doppler flowmetry (LDF) in patients with diabetic foot syndrome (DFS) and atrial fibrillation (AF) during complex therapy with the addition of direct oral anticoagulants (DOAC).

Material and methods. An open-label comparative randomized study in parallel groups was performed. Patients with neuroischemic DFS and persistent FA without previous anticoagulant therapy were randomized into two groups: combination therapy for DFS and rivaroxaban (group 1; n=24) or combination therapy for DFS and dabigatran (group 2; n=22). Changes in local status in diabetic foot ulcers, coagulogram parameters and LDF were studied at 4 and 12 weeks.

Results. Complete epithelialization of diabetic foot ulcers after 12 weeks was found in 14 (58.3%) patients in group 1, and in 10 (45.4%) patients in group 2. Statistically significant improvements in LDF parameters were found in both groups in both groups: an increase in the microcirculation index by 53.5% (p=0.02), pulse wave by 124.0% (p=0.003), respiratory wave by 59.4% (p=0.007) was found in group 1. An increase in the microcirculation index by 48.5% (p=0.02), pulse wave by 73.1% (p=0.003), respiratory wave by 47.1% (p=0.03) were found in group 2.

Conclusion. Positive statistically significant changes in epithelialization of diabetic foot ulcers and LDF parameters were found in patients with DFS and AF during 12 weeks of complex therapy with the addition of DOACs (rivaroxaban and dabigatran). Further research for DOACs in DFS patients is needed.

Retinal vascular geometry detection as a biomarker in diabetes mellitus

OBJECTIVE

To compare the vessel geometry characteristics of color fundus photographs in normal control and diabetes mellitus (DM) patients and to find potential biomarkers for early diabetic retinopathy (DR) based on a neural network vessel segmentation system and automated vascular geometry parameter analysis software.

METHODS

A total of 102 consecutive patients with type 2 DM (T2DM) and 132 healthy controls were recruited. All participants underwent general ophthalmic examinations, and retinal fundus photographs were taken with a digital fundus camera without mydriasis. Color fundus photographs were input into a dense-block generative adversarial network (D-GAN)-assisted retinal vascular segmentation system (http://www.gdcerc.cn:8081/#/login) to obtain binary images. These images were then analyzed by customized software (ocular microvascular analysis system V2.9.1) for automatic processing of vessel geometry parameters, including the monofractal dimension (D_box), multifractal dimension (D₀), vessel area ratio (R), max vessel diameter (d_max), average vessel diameter (d_ave), arc-chord ratio (A/C), and tortuosity (τ_n). Geometric differences between the healthy subjects and DM patients were analyzed. Then, regression analysis and receiver operating characteristic (ROC) curve analysis were performed to evaluate the diagnostic efficiency of the vascular geometry parameters.

RESULTS

No significant differences were observed between the baseline characteristics of each group. DM patients had lower D_box and D₀ values (1.330 ± 0.041; 1.347 ± 0.038) than healthy subjects (1.343 ± 0.048, p < 0.05; 1.362 ± 0.042, p < 0.05) and showed increasing values of d_max, d_ave, A/C, and τ_n compared with normal controls, although only the differences in d_ave and τ_n between the groups were statistically significant. In the regression analysis, d_ave and τ_n showed a good correlation with diabetes (d_ave, OR 1.765, 95% CI 1.319-2.362, p < 0.001; τ_n, OR 9.323, 95% CI 1.492-58.262, p < 0.05).

CONCLUSIONS

We demonstrated the relationship between retinal vascular geometry and the process in DM patients, showing that D_box, D₀, d_ave, and τ_n may be indicators of morphological changes in retinal vessels in DM patients and can be early biomarkers of DR.

Enhanced virulence of Plasmodium falciparum in blood of diabetic patients

Rising prevalence of diabetes in sub-Saharan Africa, coupled with continued malaria transmission, has resulted more patients dealing with both communicable and non-communicable diseases. We previously reported that travelers with type 2 diabetes mellitus (T2DM) infected with Plasmodium falciparum were three times more likely to develop severe malaria than non-diabetics. Here we explore the biological basis for this by testing blood from uninfected subjects with type 1 and type 2 diabetes, ex vivo, for their effects on parasite growth and rosetting (binding of infected erythrocytes to uninfected erythrocytes). Rosetting was associated with type 2 diabetes, blood glucose and erythrocyte sedimentation rate (ESR), while parasite growth was positively associated with blood glucose, glycated hemoglobin (HbA1c), body mass index (BMI), fibrinogen and triglycerides. This study establishes a link between diabetes and malaria virulence assays, potentially explaining the protective effect of good glycemic control against severe malaria in subjects with diabetes.

Hematological parameters of type 2 diabetic adult patients at Debre Berhan Referral Hospital, Northeast Ethiopia: A comparative cross-sectional study

BACKGROUND

Diabetes is a global public health problem and associated with metabolic, cellular, and blood disturbances. Hematological changes have been reported in diabetes and play a major role in diabetes-associated complications. However, reports are contradicting and data on hematological parameters of type 2 diabetic patients in the study area are scarce. Therefore, the aim of this study was to assess the hematological parameters of type 2 diabetic adult patients at Debre Berhan Referral Hospital, Northeast Ethiopia from May 01 to June 30, 2020.

METHODS

A comparative cross-sectional study was conducted on 268 (134 type 2 diabetic patients and 134 controls) study participants selected by systematic random sampling technique. Socio-demographic, behavioral, and clinical data were collected using a structured questionnaire and checklist. Ethical approval was obtained from Jimma University. All phase of quality assurance was maintained. Hematological parameters and blood glucose levels were determined using UniCel DxH 800 (Beckman Coulter, USA) and Biosystems A25 (Costa Brava, Spain) analyzers, respectively. Independent t-test, Mann-Whitney U-test, correlation, and logistic regression were used during data analysis. P-value <0.05 was considered as statistically significant.

RESULTS

The current study found that total white blood cell count, absolute counts of neutrophil, lymphocyte, eosinophil, and basophil, red blood cell distribution width, platelet count, and mean platelet volume were significantly higher in type 2 diabetic patients as compared to the control group (P<0.05). On the other hand, the mean hemoglobin was significantly lower in type 2 diabetic patients than the control group (P = 0.007). Anemia was found in 17.9% of type 2 diabetic patients. Longer duration of diabetes (AOR = 3.05, 95% CI = 1.12-8.34) and milk consumption (AOR = 4.60, 95% CI = 1.50-14.00) were significantly associated with anemia.

CONCLUSION

This study showed a statistically significant variation in some hematological parameters of type 2 diabetic patients compared to control group. Anemia among type 2 diabetic patients was found to be a mild public health problem. Therefore, routine screening of hematological parameters should be considered for proper management of type 2 diabetic patients. Close attention should also be given to the duration of diabetes and dietary practice.

Evaluation of retrobulbar circulation in type 2 diabetic patients using color Doppler imaging

Purpose:

To investigate the retrobulbar circulatory parameters in type 2 diabetes mellitus patients with color Doppler imaging (CDI) and compare the results with nondiabetic controls.

Methods:

This prospective study included 50 type 2 diabetic patients and 50 age-matched controls. Seven field stereo fundus photography was used to diagnose and classify diabetic retinopathy (DR). Diabetic patients were further divided into two: Group 1, consisted of patients with no DR, mild and moderate non-proliferative DR (n = 36); Group 2, severe nonproliferative and proliferative DR (n = 14). CDI was performed using Philips iU22 xMATRIX ultrasound. The peak systolic velocity (PSV), end-diastolic velocity (EDV), resistivity index (RI) and pulsatile index (PI) of ophthalmic (OA), posterior ciliary artery (PCA), and central retinal artery (CRA) along with central retinal vein (CRV) were recorded.

Results:

RI in the ophthalmic artery was significantly higher in both DR groups than the control group (P = 0.000). Diabetic Group 1 had decreased blood flow velocity (PSV and EDV) in PCA compared to controls (P = 0.046 and P = 0.010, respectively). Group 2 DR had significantly reduced EDV and increased RI in CRA compared to Group 1 (P = 0.015). Binary logistic regression analysis revealed glycosylated hemoglobin and RI of OA to be independent risk factors of DR.

Conclusion:

Significant changes in resistivity index and flow velocities were observed in the retrobulbar vessels, especially in ophthalmic artery in diabetics compared to controls. CDI with results of increased resistance or decreased flow could be useful to predict individuals at higher risk for developing severe DR.

SGLT2 Inhibitor-Induced Low-Grade Ketonemia Ameliorates Retinal Hypoxia in Diabetic Retinopathy-A Novel Hypothesis

Diabetic retinopathy (DR) is a well-recognized microvascular complication of diabetes. Growing evidence suggests that, in addition to retinal vascular damage, there is significant damage to retinal neural tissue in DR. Studies reveal neuronal damage before clinically evident vascular lesions and DR is now classified as a neurovascular complication. Hyperglycemia causes retinal damage through complex metabolic pathways leading to oxidative stress, inflammation, vascular damage, capillary ischemia, and retinal tissue hypoxia. Retinal hypoxia is further worsened by high oxygen consumption in the rods. Persistent hypoxia results in increases in vascular endothelial growth factor (VEGF) and other pro-angiogenic factors leading to proliferative DR/macular edema and progressive visual impairment. Optimal glucose control has favorable effects in DR. Other treatments for DR include laser photocoagulation, which improves retinal oxygenation by destroying the high oxygen consuming rods and their replacement by low oxygen consuming glial tissue. Hypoxia is a potent stimulator of VEGF, and intravitreal anti-VEGF antibodies are effective in regressing macular edema and in some studies, retinal neovascularization. In this review, we highlight the complex pathophysiology of DR with a focus on retinal oxygen/fuel consumption and hypoxic damage to retinal neurons. We discuss potential mechanisms through which sodium-glucose cotransporter 2 (SGLT2) inhibitors improve retinal hypoxia-through ketone bodies, which are energetically as efficient as glucose and yield more ATP per molecule of oxygen consumed than fat, with less oxidative stress. Retinal benefits would occur through improved fuel energetics, less hypoxia and through the anti-inflammatory/oxidative stress effects of ketone bodies. Well-designed studies are needed to explore this hypothesis.

Susceptibility for Some Infectious Diseases in Patients With Diabetes: The Key Role of Glycemia

Uncontrolled diabetes results in several metabolic alterations including hyperglycemia. Indeed, several preclinical and clinical studies have suggested that this condition may induce susceptibility and the development of more aggressive infectious diseases, especially those caused by some bacteria (including Chlamydophila pneumoniae, Haemophilus influenzae, and Streptococcus pneumoniae, among others) and viruses [such as coronavirus 2 (CoV2), Influenza A virus, Hepatitis B, etc.]. Although the precise mechanisms that link glycemia to the exacerbated infections remain elusive, hyperglycemia is known to induce a wide array of changes in the immune system activity, including alterations in: (i) the microenvironment of immune cells (e.g., pH, blood viscosity and other biochemical parameters); (ii) the supply of energy to infectious bacteria; (iii) the inflammatory response; and (iv) oxidative stress as a result of bacterial proliferative metabolism. Consistent with this evidence, some bacterial infections are typical (and/or have a worse prognosis) in patients with hypercaloric diets and a stressful lifestyle (conditions that promote hyperglycemic episodes). On this basis, the present review is particularly focused on: (i) the role of diabetes in the development of some bacterial and viral infections by analyzing preclinical and clinical findings; (ii) discussing the possible mechanisms by which hyperglycemia may increase the susceptibility for developing infections; and (iii) further understanding the impact of hyperglycemia on the immune system.

Data-driven cardiovascular flow modelling: examples and opportunities

High-fidelity blood flow modelling is crucial for enhancing our understanding of cardiovascular disease. Despite significant advances in computational and experimental characterization of blood flow, the knowledge that we can acquire from such investigations remains limited by the presence of uncertainty in parameters, low resolution, and measurement noise. Additionally, extracting useful information from these datasets is challenging. Data-driven modelling techniques have the potential to overcome these challenges and transform cardiovascular flow modelling. Here, we review several data-driven modelling techniques, highlight the common ideas and principles that emerge across numerous such techniques, and provide illustrative examples of how they could be used in the context of cardiovascular fluid mechanics. In particular, we discuss principal component analysis (PCA), robust PCA, compressed sensing, the Kalman filter for data assimilation, low-rank data recovery, and several additional methods for reduced-order modelling of cardiovascular flows, including the dynamic mode decomposition and the sparse identification of nonlinear dynamics. All techniques are presented in the context of cardiovascular flows with simple examples. These data-driven modelling techniques have the potential to transform computational and experimental cardiovascular research, and we discuss challenges and opportunities in applying these techniques in the field, looking ultimately towards data-driven patient-specific blood flow modelling.

Acute Cycling Exercise Induces Changes in Red Blood Cell Deformability and Membrane Lipid Remodeling

Here we describe the effects of a controlled, 30 min, high-intensity cycling test on blood rheology and the metabolic profiles of red blood cells (RBCs) and plasma from well-trained males. RBCs demonstrated decreased deformability and trended toward increased generation of microparticles after the test. Meanwhile, metabolomics and lipidomics highlighted oxidative stress and activation of membrane lipid remodeling mechanisms in order to cope with altered properties of circulation resulting from physical exertion during the cycling test. Of note, intermediates from coenzyme A (CoA) synthesis for conjugation to fatty acyl chains, in parallel with reversible conversion of carnitine and acylcarnitines, emerged as metabolites that significantly correlate with RBC deformability and the generation of microparticles during exercise. Taken together, we propose that RBC membrane remodeling and repair plays an active role in the physiologic response to exercise by altering RBC properties.

Investigating the Dynamics of the Magnetic Micromotors in Human Blood

The field of micromotors has been growing exponentially with increased emphasis on biomedical applications, with various in vivo demonstrations of targeted drug delivery, biosensing, and gene delivery, among others. In parallel, these micromotors have been recently used for probing the rheological properties of both intra- and extracellular environments. Here, we demonstrate the application of magnetic micromotors for investigation of rheological properties of human blood. While there are several techniques to sense mechanical properties of blood, such as deformability of the red blood cells, this is the first experimental observation of using micromotors for these biophysical investigations. We hope that this will lead to a better understanding of the nature of interactions of micromotors with biological systems and expand the scope of micromotors for probing other related systems, such as interstitial fluids and other complex biological fluids.

Multiple autoimmune syndrome complicating the management of diabetic retinopathy

Purpose

Observations

Conclusion and Importance

Sodium-Glucose Cotransporter Type 2 (SGLT-2) Inhibitors and Ketogenesis: the Good and the Bad

PURPOSE OF REVIEW

The micro/macrovascular complications of diabetes cause considerable morbidity and premature mortality. The SGLT2 inhibitors are the first diabetes medications with significant benefits on microvascular disease (nephropathy) and macrovascular cardiovascular disease. In this review, we evaluate one of the potential mechanisms for these cardiorenal benefits-the production of ketones, their benefits, and risks.

RECENT FINDINGS

In recent cardiovascular outcome trials (CVOTs), the SGLT2 inhibitors demonstrated significant cardiorenal benefits and they are now approved to reduce CV events/death, heart failure hospitalization, and progression to end-stage renal disease. Glucosuria induced by the SGLT2 inhibitors leads to increased ketone production. Ketones are an efficient fuel source and can improve myocardial and renal function. Further, the ketone body beta-hydroxybutyrate exhibits anti-inflammatory/anti-oxidative actions, which favorably impact myocardial and renal remodeling/fibrosis. Uncontrolled ketogenesis leads to ketoacidosis, especially during conditions of acute illness and excessive insulin dose reductions. The SGLT2 inhibitors have demonstrated significant cardiorenal benefits in large CVOTs. Studies are in progress to elucidate whether SGLT2 inhibitor-induced low-grade hyperketonemia contributes to these benefits.