Blood Viscosity Research Articles

A Compact and Novel Photoacoustic Sensing Technique for In Vitro Characterization of Blood Viscosity: A Phantom-Based Study

A Compact and Novel Photoacoustic Sensing Technique for In Vitro Characterization of Blood Viscosity: A Phantom-Based Study

Ginsenosides ameliorates high altitude-induced hypoxia injury in lung and kidney tissues by regulating PHD2/HIF-1α/EPO signaling pathway.

Background: The primary constituent of ginseng, known as ginsenosides (GS), has been scientifically demonstrated to possess anti-fatigue, anti-hypoxia, anti-inflammatory, and antioxidant properties. However, the effect and mechanisms of GS on tissue injury induced by high-altitude hypoxia still remain unclear. Aim of the study: This study aims to investigate the protective effect of GS on a high-altitude hypoxia model and explore its mechanism. Materials and methods: Sprague-Dawley rats were placed in a high-altitude simulation chamber for 48h (equivalent to an altitude of 6,000m) to establish a high-altitude hypoxia model. We assessed the anti-hypoxic efficacy of GS through blood gas analysis, complete blood count, and hemorheology analysis. We used H&E and hypoxia probe assays to evaluate the protective effect of GS on organ ischemia-induced injury. Further, we used ELISA and qPCR analysis to detect the levels of inflammatory factors and oxidative stress markers. Immunohistochemistry and immunofluorescence staining were performed to determinate protein expression of hypoxia inducible factor 1-alpha (HIF-1α), erythropoietin (EPO), and prolyl hydroxylase 2 (PHD2). Results: In the survival experiment of anoxic mice, 100mg/kg of GS had the best anti-anoxic effect. GS slowed down the weight loss rate of rats in hypoxic environment. In the fluorescence detection of hypoxia, GS reduced the fluorescence signal value of lung and kidney tissue and alleviated the hypoxia state of tissue. Meanwhile GS improved blood biochemical and hematological parameters. We also observed that GS treatment significantly decreased oxidative stress damage in lung and kidney tissues. Further, the levels of inflammatory factors, IL-1β, IL-6, and TNF-α were reduced by GS. Finally, GS regulated the PHD2/HIF-1α/EPO signaling pathway to improve blood viscosity and tissue hyperemia damage. Conclusion: GS could alleviate high-altitude induced lung and kidney damage by reducing the level of inflammation and oxidative stress, improving blood circulation through the PHD2/HIF-1α/EPO pathway.

A viscosity measurement technique for ultra-low sample volumes.

We describe a unique method to measure the viscosity of liquids based on the fluid mechanics of thin films. A drop of sample is spread over a substrate by contacting a blade with the drop and moving the blade across the substrate. The thickness of the film is determined by the capillary number, which measures the competition between the viscous force that smears the liquid over the glass slide and the surface tension that resists the deformation of the interface. We show that the length of the smear for a fixed sample volume is also set by capillary number and can be used as a reliable measure of fluid viscosity. The technique is especially suitable for viscosity measurements of biological fluids where viscosities are low and sample sizes are small. The technique can detect small changes in blood viscosity enabling it to be used as a non-specific, screening tool for diseases and therapeutic interventions.

Structural and thermodynamic characterization of allosteric transitions in human serum albumin with metadynamics simulations.

Human serum albumin (HSA) is the most prominent protein in blood plasma, responsible for the maintenance of blood viscosity and transport of endogenous and exogenous molecules. Fatty acids (FA) are the most common ligands of HSA and their binding can modify the protein's structure. The protein can assume two well-defined conformations, referred to as 'Neutral' and 'Basic'. The Neutral (N) state occurs at pH close to 7.0 and in the absence of bound FA. The Basic (B) state occurs at pH higher than 8.0 or when the protein is bound to long-chain FA. HSA's allosteric behaviour is dependent on the number on FA bound to the structure. However, the mechanism of this allosteric regulation is not clear. To understand how albumin changes its conformation, we compared a series of HSA structures deposited in the protein data bank to identify the minimum amount of FA bound to albumin, which is enough to drive the allosteric transition. Thereafter, non-biased molecular dynamics (MD) simulations were used to track protein's dynamics. Surprisingly, running an ensemble of relatively short MD simulations, we observed rapid transition from the B to the N state. These simulations revealed differences in the mobilities of the protein's subdomains, with one domain unable to fully complete its transition. To track the transition dynamics in full, we used these results to choose good geometrical collective variables for running metadynamics simulations. The metadynamics calculations showed that there was a low energy barrier for the transition from the B to the N state, while a higher energy barrier was observed for the N to the B transition. These calculations also offered valuable insights into the transition process.

Influence of magnetotherapy on various systems of the body and on the process of wound healing in children with cleft lip and palate

In this article we present the results of magnetic therapy on the wound healing process in children with cleft lip and palate after cheiloplasty surgery. At the same time, there is an improvement in metabolic processes in tissues, which contributes to their proper nutrition and restoration.Inflammation and associated soft tissue swelling are eliminated. Locally, blood vessels dilate and blood supply improves. The pain is relieved.Magnetotherapy is a method of physiotherapy that uses magnetic fields of varying strengths and frequencies for the treatment, rehabilitation or prevention of diseases. To carry it out, stationary and portable devices have been developed. The principle is simple: one or more electromagnetic applicators are installed on certain areas of the body, or the patient is placed in a large-diameter magnetic chamber or on a special mattress. The method is based on the fact that a magnetic field affects electrically charged particles moving in the human body. They are found in biological fluids - blood, lymph, cytoplasm of cells. Under the influence of a magnet, weak electric currents arise in these environments. They cause many responses: metabolism, blood properties, the speed of transmission of nerve impulses change, microcirculation and the delivery of oxygen and micronutrients improve. This leads to the following effects: reduction of tissue swelling, suppression of the inflammatory process, local anesthesia, reduction of blood viscosity, normalization of blood pressure, acceleration of healing and tissue restoration, stimulation of the immune system.

Comment on "Dynamics and rheology of vesicles under confined Poiseuille flow" by Z. Gou, H. Zhang, A. Nait-Ouhra, M. Abbasi, A. Farutin and C. Misbah, Soft Matter, 2023, 19, 9101.

In a recent paper, [Gou et al., Soft Matter, 2023, 19, 9101-9114] studied numerically the viscosity of a confined suspension of vesicles flowing in a channel as a function of vesicle concentration. In order to discuss the genericity of the observed behaviour, namely a nearly constant effective viscosity at low concentrations, we complement their study by a comparison with the few existing ones in the literature. In particular, we highlight that they fail to reproduce well established results for blood viscosity in microcirculation, thereby suggesting that the conclusions regarding the optimization of cell transport and oxygenation may not apply. We conclude with a quick discussion on potential improvements regarding numerical modeling, as long as physiological relevance is sought.

Hemorheology in thyroid abnormalities: old team player, new insights

Thyroid dysfunctions significantly impact various physiological processes, extending their influence on hemorheological properties and microcirculation. This comprehensive review explores the intricate relationship between thyroid disorders and hemorheology, emphasizing the substantial effects on blood flow dynamics and tissue perfusion. Examining the alterations in blood viscosity, erythrocyte behavior, and microvascular circulation in both hypothyroidism and hyperthyroidism reveals crucial insights into the pathophysiology of these conditions. Furthermore, elucidating the hemorheological changes associated with thyroid dysfunctions offers potential avenues for improved clinical management strategies. This review synthesizes current research findings, highlighting the importance of considering hemorheological aspects in understanding the complexities of thyroid-related complications and advancing patient care paradigms.

Insights into the Pathophysiology and Therapeutic Targets of Consequences Induced by Polycythemia in COPD

ABSTRACT: Polycythemia, characterized by an excess of red blood cells (RBCs), is a common occurrence in individuals with chronic obstructive pulmonary disease (COPD) due to chronic hypoxia resulting from impaired lung function. While polycythemia may have some protective effects for COPD patients on long-term oxygen therapy, it can also increase the risk of life-threatening complications such as pulmonary embolism (PE). This review explores the impact of polycythemia on COPD patients, delving into its epidemiology, risk factors, and potential consequences. The prevalence of polycythemia in COPD varies from 6% to 10.2% in outpatient settings and is associated with factors like smoking, male gender, impaired lung function, and severe hypoxemia. The elevated red blood cell count can thicken the blood, increasing the risk of blood clots and cardiovascular complications. Proper management of polycythemic COPD involves addressing increased blood viscosity, managing thromboembolic risks, and optimizing cardiovascular health. Therapeutic interventions include phlebotomy, low-dose aspirin, and oxygen therapy to reduce complications and improve outcomes. Additionally, new cytoreductive therapies may offer promising treatment options for primary polycythemia. However, further research is required to enhance our understanding and refine care for individuals with polycythemic COPD, with the ultimate goal of mitigating complications, improving quality of life, and enhancing long-term prognosis. Clinicians must remain vigilant in managing polycythemia in COPD to optimize patient outcomes and reduce the burden of associated complications.

Therapeutic efficacy and pharmacological mechanism of Yindan Xinnaotong soft capsule on acute ischemic stroke: a meta-analysis and network pharmacology analysis.

Yindan Xinnaotong soft capsule (YDXNT), a traditional Chinese medicine preparation, has shown a promising effect in the treatment of acute ischemic stroke (AIS). The goal of this study was to investigate the therapeutic effects and pharmacological mechanisms of YDXNT on AIS. Randomized controlled trials were searched and screened. Review Manager 5.4 was used for a meta-analysis. Active ingredients and targets of YDXNT were extracted from the Traditional Chinese Medicine Systems Pharmacology Database, Bioinformatics Analysis Tool for Molecular mechANism of Traditional Chinese Medicine, and Encyclopaedia of Traditional Chinese Medicine. AIS-related targets were retrieved from GeneCards, OMIM, and DrugBank databases. We constructed PPI and ingredient-target networks, performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, and conducted molecular docking. The YDXNT group had a higher total effective rate and a higher Barthel Index score. YDXNT reduced the low-density lipoprotein cholesterol and the whole blood viscosity at high and shear rates. Our study identified 313 ingredients and 1196 common targets. The key ingredients were mainly quercetin, neocryptotanshinone II, miltionone I, neotanshinone C, and tanshiquinone B, and the key targets were mainly SRC, MAPK3, AKT1, MAPK1, and JUN. GO analysis showed that the core targets mainly involved in atherosclerosis and neural apoptosis. The core pathways were lipid and atherosclerosis, PI3K-Akt, MAPK, and other pathways. Key ingredients exhibited robust binding interactions with core targets. YDXNT could effectively improve the total effective rate, ability of daily life, blood lipids, and blood viscosity. Antiatherosclerotic and neuroprotective effects are the main pharmacological mechanisms.Registration number: CRD42023400127.

Network pharmacology and experimental verification to explore the anti-superficial thrombophlebitis mechanism of Mailuo shutong pill

Ethnopharmacological relevanceMailuo shutong pill (MLST) has been widely used in clinical treatment of superficial thrombotic phlebitis (STP). Nevertheless, the major active components of MLST and the mechanism of synergistic action have not been reported. Aim of the studyThe present study aimed to evaluate the improving effects and the underlying mechanism of MLST on mannitol-induced STP in rabbits. Material and methodsIn this study, Ultrahigh-performance liquid chromatography electrospray ionization quadrupole-exactive orbitrap mass spectrometry (UHPLC-ESI-Q-Exactive-Orbitrap-MS) was used to analyze and identify the chemical composition of MLST and the prototype components absorbed into the blood. Then, according to the prototype components in serum, the targets and mechanisms of MLST were explored by applying network pharmacology. The rabbit model of STP was established by injecting 20% mannitol into bilateral auricular vein. The pathological changes of rabbit ear tissues, inflammatory factors, coagulation function and hemorheology were detected. In addition, molecular docking verified the interaction between the main active ingredient and the key target. Finally, the PI3K/AKT pathway and its regulated downstream pathways were verified by Western blot. ResultsA total of 96 MLST components and 53 prototypical components absorbed into the blood were successfully identified. Based on network pharmacology, PI3K/AKT pathway and 10 chemical components closely related to this pathway were obtained. Hematoxylin-eosin (HE) staining results indicated that MLST effectively improved of the pathological damage of ear tissues. MLST decreased levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and C-reactive protein (CRP). The expression of platelets (PLT) and fibrinogen concentration (FIB) was decreased, while prothrombin time (PT) and activated partial thromboplastin time (APTT) were prolonged. In addition, the plasma viscosity and whole blood viscosity in the MLST groups were significantly decreased. The more important discovery was that the expressions of P-PI3K, VEGF, P-AKT, P-IκB-α, P–NF-κB, NLRP3, ASC, Cleaved IL-1β and Cleaved Caspase-1 were effectively reversed after treatment with MLST. ConclusionsThis study comprehensively analyzed and characterized the chemical composition of MLST and the prototypical components absorbed into the blood. This study strongly confirmed the pharmacodynamic effect of MLST on STP. More importantly, this pharmacodynamic effect was achieved through inhibition of the PI3K/AKT pathway and its regulated NF-κB and NLRP3 pathways.

Standardized viscosity as a source of error in computational fluid dynamic simulations of cerebral aneurysms.

Computational fluid dynamics (CFD) simulations are a powerful tool for studying cerebral aneurysms, capable of evaluating hemodynamics in a way that is infeasible with imaging alone. However, the difficulty of incorporating patient-specific information and inherent obstacles of in vivo validation have limited the clinical usefulness of CFD of cerebral aneurysms. In this work we investigate the effect of using standardized blood viscosity values in CFD simulations of cerebral aneurysms when compared to simulations of the same aneurysms using patient-specific viscosity values derived from hematocrit measurements. The objective of this work is to determine the level of error, on average, that is, caused by using standardized values of viscosity in CFD simulations of cerebral aneurysms. By quantifying this error, we demonstrate the need for incorporating patient-specific viscosity in future CFD investigations of cerebral aneurysms. CFD simulations of forty-one cerebral aneurysms were conducted using patient-specific boundary conditions. For each aneurysm two simulations were conducted, one utilizing patient-specific blood viscosity derived from hematocrit measurements and another using a standardized value for blood viscosity. Hemodynamic parameters such as wall shear stress (WSS), wall shear stress gradient (WSSG), and the oscillatory shear index (OSI) were calculated for each of the simulations for each aneurysm. Paired t-tests for differences in the time-averaged maps of these hemodynamic parameters between standardized and patient-specific viscosity simulations were conducted for each aneurysm. Bland-Altman analysis was used to examine the cohort-wide changes in the hemodynamic parameters. Subjects were broken into two groups, those with higher than standard viscosity and those with lower than standard viscosity. An unpaired t-test was used to compare the percent change in WSS, WSSG, and OSI between patient-specific and standardized viscosity simulations for the two cohorts. The percent changes in hemodynamic parameters were correlated against the direction and magnitude of percent change in viscosity, aneurysm size, and aneurysm location. For all t-tests, a Bonferroni-corrected significance level of 0.0167 was used. 63.2%, 41.5%, and 48.7% of aneurysms showed statistically significant differences between patient-specific and standardized viscosity simulations for WSS, WSSG, and OSI respectively. No statistically significant difference was found in the percent changes in WSS, WSSG, and OSI between the group with higher than standard viscosity and those with lower than standard viscosity, indicating an increase in viscosity can cause either an increase or decrease in each of the hemodynamic parameters. On a study-wide level no significant bias was found in either direction for WSS, WSSG, or OSI between the simulation groups due to the bidirectional effect of changing viscosity. No correlation was found between percent change of viscosity and percent change of WSS, WSSG, or OSI, meaning an after-the-fact correction for patient-specific viscosity is not feasible. Standardizing viscosity values in CFD of cerebral aneurysms has a large and unpredictable impact on the calculated WSS, WSSG, and OSI when compared to CFD simulations of the same aneurysms using a patient-specific viscosity. We recommend implementing hematocrit-based patient-specific blood viscosity values for all CFD simulations of cerebral aneurysms.

Investigation of Blood Supply to the Macular Region of the Retina in Chronic Myeloproliferative Diseases

Chronic myeloproliferative diseases (CMPD) are tumor diseases of hematopoietic tissue with increased proliferation of one or more lines of myelopoiesis. Quite often with this pathology there are find references to damage to the organ of vision. With CMPD changes in the composition of peripheral blood are observed, leading to changes in the rheology of blood and contributing to the deterioration of microcirculation of eye tissues. In addition, abnormal proliferation of hematopoietic cells and prolonged specific therapy weaken the body’s immune system, contributing to the development of systemic inflammation. These processes can lead to deterioration of blood supply to eye tissues, in particular in the macular region. Purpose. To evaluate vessel density (VD) in the superficial and deep vascular plexuses of retina and the area of foveolar avascular zone (FAZ) using optical coherence tomography with angiography function (OCTA) in patients with CMPD. Patients and methods. The study included 25 patients with CMPD (50 eyes) and 20 volunteers (40 eyes), comparable in gender and age, without a history of hemoblastosis. All the examined patients underwent comprehensive ophthalmological diagnostics, including OCTA. Results. According to the results, patients with CMPD revealed a significant decrease in VD in all sectors (except the foveolar zone) in both studied vascular plexuses, as well as a significant increase in area of FAZ compared to the control group. Conclusion. A decrease in VD in the vascular plexuses of the retina, as well as an increase in area of FAZ, are signs of deterioration of retinal blood supply and retinal ischemia. It is possible that these changes may lead to violations of blood rheology, as well as chronic systemic inflammation observed in patients with CMPD. Deterioration of blood flow and prolonged retinal hypoxia can contribute to serious visual impairment of patients. In this regard, patients with CMPD require more detailed monitoring, possibly with correction of the main treatment.

Expedition 5300: limits of human adaptations in the highest city in the world.

Exposure to chronic hypobaric hypoxia imposes a significant physiological burden to more than 80 million humans living above 2500m throughout the world. Among them, 50000 live in the world's highest city, La Rinconada, located at 5000-5300m in southern Peru. Expedition 5300 is the first scientific and medical programme led in La Rinconada to investigate the physiological adaptations and altitude-related health issues in this unique population. Dwellers from La Rinconada have very high haemoglobin concentration (20.3±2.4g/dL; n=57) and those with chronic mountain sickness (CMS) exhibit even higher concentrations (23.1±1.7g/dL; n=150). These values are associated with large total haemoglobin mass and blood volume, without an associated iron deficit. These changes in intravascular volumes lead to a substantial increase in blood viscosity, which is even larger in CMS patients. Despite these large haematological changes, 24h blood pressure monitoring is essentially normal in La Rinconada, but some results suggest impaired vascular reactivity. Echocardiography revealed large right heart dilatation and high pulmonary arterial pressure as well as left ventricle concentric remodelling and grade I diastolic dysfunction. These changes in heart dimension and function tend to be more severe in highlanders with CMS. Polygraphy evaluations revealed a large reduction in nocturnal pulse oxygen saturation (median SpO2 =79%), which is even more severe in CMS patients who also tended to show a higher oxygen desaturation index. The population of La Rinconada offers a unique opportunity to investigate the human responses to chronic severe hypoxia, at an altitude that is probably close to the maximum altitude human beings can permanently tolerate without presenting major health issues.

Blood Rheology and Hemodynamics.

Seminars in Thrombosis and Hemostasis (STH) celebrates 50 years of publishing in 2024. To celebrate this landmark event, STH is republishing some archival material. This article represents the most highly cited paper ever published in STH. The original abstract follows.Blood is a two-phase suspension of formed elements (i.e., red blood cells [RBCs], white blood cells [WBCs], platelets) suspended in an aqueous solution of organic molecules, proteins, and salts called plasma. The apparent viscosity of blood depends on the existing shear forces (i.e., blood behaves as a non-Newtonian fluid) and is determined by hematocrit, plasma viscosity, RBC aggregation, and the mechanical properties of RBCs. RBCs are highly deformable, and this physical property significantly contributes to aiding blood flow both under bulk flow conditions and in the microcirculation. The tendency of RBCs to undergo reversible aggregation is an important determinant of apparent viscosity because the size of RBC aggregates is inversely proportional to the magnitude of shear forces; the aggregates are dispersed with increasing shear forces, then reform under low-flow or static conditions. RBC aggregation also affects the in vivo fluidity of blood, especially in the low-shear regions of the circulatory system. Blood rheology has been reported to be altered in various physiopathological processes: (1) Alterations of hematocrit significantly contribute to hemorheological variations in diseases and in certain extreme physiological conditions; (2) RBC deformability is sensitive to local and general homeostasis, with RBC deformability affected by alterations of the properties and associations of membrane skeletal proteins, the ratio of RBC membrane surface area to cell volume, cell morphology, and cytoplasmic viscosity. Such alterations may result from genetic disorders or may be induced by such factors as abnormal local tissue metabolism, oxidant stress, and activated leukocytes; and (3) RBC aggregation is mainly determined by plasma protein composition and surface properties of RBCs, with increased plasma concentrations of acute phase reactants in inflammatory disorders a common cause of increased RBC aggregation. In addition, RBC aggregation tendency can be modified by alterations of RBC surface properties because of RBC in vivo aging, oxygen-free radicals, or proteolytic enzymes. Impairment of blood fluidity may significantly affect tissue perfusion and result in functional deteriorations, especially if disease processes also disturb vascular properties.

Analysis of the Suitability of an Effective Viscosity to Represent Interactions Between Red Blood Cells in Shear Flow.

Many methods to computationally predict red blood cell damage have been introduced, and among these are Lagrangian methods that track the cells along their pathlines. Such methods typically do not explicitly include cell-cell interactions. Due to the high volume fraction of red blood cells (RBCs) in blood, these interactions could impact cell mechanics and thus the amount of damage caused by the flow. To investigate this question, cell-resolved simulations of red blood cells in shear flow were performed for multiple interacting cells, as well as for single cells in unbounded flow at an effective viscosity. Simulations run without adjusting the bulk viscosity produced larger errors unilaterally and were not considered further for comparison. We show that a periodic box containing at least 8 cells and a spherical harmonic of degree larger than 10 are necessary to produce converged higher-order statistics. The maximum difference between the single-cell and multiple-cell cases in terms of peak strain was 3.7%. To achieve this, one must use the whole blood viscosity and average over multiple cell orientations when adopting a single-cell simulation approach. The differences between the models in terms of average strain were slightly larger (maximum difference of 6.9%). However, given the accuracy of the single-cell approach in predicting the maximum strain, which is useful in hemolysis prediction, and its computational cost that is orders of magnitude less than the multiple-cell approach, one may use it as an affordable cell-resolved approach for hemolysis prediction.

Energy spectrum analysis on a red blood cell model.

It is important to understand the dynamics of red blood cells (RBCs) in blood flow. This requires the formulation of coarse-grained RBC models that reproduce the hydrodynamic properties of blood accurately. One of the models that successfully reproduces the rheology and morphology of blood has been proposed by Fedosov et al. [Comput. Methods Appl. Mech. Eng. 199, 1937-1948 (2010)]. The proposed RBC model contains several parameters whose values are determined by either various experiments or physical requirements. In this study, we developed a new method of determining parameter values precisely from the fluctuations of the RBC membrane. Specifically, we studied the relationship between the spectra of the fluctuations and model parameters. Characteristic peaks were observed in the spectra, whose peak frequencies were dependent on the parameter values. In addition, we investigated the spectra of the radius of gyration. We identified the peaks originating from the spring potential and the volume-conserving potential appearing in the spectra. These results lead to the precise experimental determination of the parameters used in the RBC model.

Hemorheology and Inflammatory Marker Changes in Patients with Acute Ischemic Stroke after Intravenous Thrombolysis with Mechanical Thrombectomy.

To investigate hemorheology and inflammatory marker changes after treatment for acute ischemic stroke (AIS) using intravenous thrombolysis (IVT) with mechanical thrombectomy (MT). We retrospectively reviewed clinical records of patients with AIS (n=83) treated in The First Affiliated Hospital of Bengbu Medical College between January 2021 and December 2022 (n=83). The control group consisted of 38 patients who underwent IVT alone and the observation group consisted of 45 patients who underwent IVT with MT. We compared differences in mean variables related to hemorheology, inflammatory markers, and total efficacy between the two groups. We found that hemorheology values (plasma viscosity [PV], whole blood viscosity [WBV], fibrinogen [FIB], and hematocrit [HCT]), and the levels of inflammatory markers (tumor necrosis factor ɑ [TNF-ɑ] and interleukin-6 [IL-6]) were higher in the control group than in the observation group after treatment (P<0.05). In addition, the total efficacy of the observation group (93.3%) was higher than that in the control group (76.3%; P=0.016). The clinical efficacy of combined IVT and MT in the treatment of AIS is superior to IVT alone, improving levels of hemorheology and inflammatory markers in patients with AIS.

Investigation of Erying–Powell fluid flow in the elliptical multi‐stenosed artery: Application of perturbation method via polynomial solutions

AbstractIn the current work, we analyzed the non‐Newtonian rheology of blood through a multi‐stenosed artery with a cross‐section of elliptical shape. The blood is regarded as Erying–Powell fluid, and flow is considered to have no slip at the stenotic wall. The mathematical model is processed to a non‐dimensional form, and conditions of mild stenosis are utilized to decrease its nonlinearity. The resulting equations are solved by applying the perturbation technique by considering the fluid characteristic parameter as the perturbation parameter. The solution is completed by using the polynomial of degree four. The solutions of mathematical equations are deeply examined by graphical analysis. The non‐Newtonian impacts are predominant in the surrounding of the stenosed wall along the minor axis of the elliptical artery. The height of stenosis affects the pressure rise and flow resistance. The shear stress at the arterial wall is very high in the stenotic region and has more potent effects in the neighboring boundary point on the minor axis. Progressive stenosis causes a reduction in the blood flow velocity surrounding the arterial wall due to higher resistance to the flow. However, the velocity improves near the center line of the artery. Further, the fluid's velocity is very high in the constricted (stenotic zone) region.

An in vivo investigation on the effects of stent implantation on hematological and hemorheological parameters.

Even though cardiovascular stenting is widely used for the treatment of coronary artery disease, information on how it can affect the hematological and hemorheological profile is scarce in the literature. Most of the work on this issue is based on theoretical or computational fluid dynamics models, lacking in-depth in vitro and in vivo experimental verification. This work investigates, in an in vivo setting, the effects of stenting and the implantation time-course on hematological and hemorheological parameters that could potentially compromise the device's functionality and longevity. Custom-made self-expanding nitinol stents were implanted in the common carotid artery of male CD1 mice. Whole blood samples were collected from control (non-stented) and stented animals at 5 and 10 weeks post-implantation. Hematological measurements and blood viscosity, red blood cell aggregation, and deformability were performed using standard techniques. Implant-induced changes were observed in some of the hematological and hemorheological indices. Blood viscosity seems to have been negatively affected by an increased hematocrit and reduced RBC deformability, at 10 weeks post-implantation, despite a slight decrease in RBC aggregation. Although the alterations observed may be the result of the peri-implant inflammatory response, the physiological consequences due to hemorheological changes need to be further investigated.

Assessing Mailuoning injection in wound healing and thrombophlebitis management: A rat model study.

Thrombophlebitis is the inflammatory condition characterized by obstruction of one or more vessels, commonly in the legs, due to the formation of blood clots. It has been reported that traditional Chinese medicine, including Mailuoning injection, is advantageous for treating inflammatory and blood disorders. This research assessed the therapeutic efficacy of Mailuoning injection in the treatment of thrombophlebitis in rodents, as well as investigated its impact on fibrinolysis, inflammation, and coagulation. An experimental setup for thrombophlebitis was established in rodents via modified ligation technique. Five groups comprised the animals: sham operation group, model group, and three Mailuoning treatment groups (low, medium, and high dosages). The pain response, edema, coagulation parameters (PT, APTT, TT, FIB), serum inflammatory markers (IL-6, TNF-α, CRP), and expression levels of endothelial markers (ICAM-1, VCAM-1, NF-κB) were evaluated. Blood flow and vascular function were further assessed by measuring hemorheological parameters and the concentrations of TXB2, ET, and 6-k-PGF1α. In contrast to the sham group, model group demonstrated statistically significant increases in endothelial expression levels, coagulation latencies, and inflammatory markers (p < 0.05). The administration of mailing, specifically at high and medium dosages, resulted in a substantial reduction in inflammatory markers, enhancement of coagulation parameters, suppression of ICAM-1 and VCAM-1 expression, and restoration of hemorheological measurements to baseline (p < 0.05). Significantly higher concentrations of 6-k-PGF1α and lower levels of TXB2 and ET were observed in high-dose group, suggesting that pro- and anti-thrombotic factors were restored to equilibrium. Utilization of Mailuoning injection in rat model of thrombophlebitis exhibited significant therapeutic impact. This effect was manifested through pain alleviation, diminished inflammation, enhanced blood viscosity and facilitation of fibrinolysis. The study indicated that Mailuoning injection may serve as a viable therapeutic option for thrombophlebitis, potentially aiding in the improvement of wound healing by virtue of its anti-inflammatory and blood flow-enhancing characteristics.